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Sample records for contact problems current

  1. Scalable algorithms for contact problems

    Dostál, Zdeněk; Sadowská, Marie; Vondrák, Vít

    2016-01-01

    This book presents a comprehensive and self-contained treatment of the authors’ newly developed scalable algorithms for the solutions of multibody contact problems of linear elasticity. The brand new feature of these algorithms is theoretically supported numerical scalability and parallel scalability demonstrated on problems discretized by billions of degrees of freedom. The theory supports solving multibody frictionless contact problems, contact problems with possibly orthotropic Tresca’s friction, and transient contact problems. It covers BEM discretization, jumping coefficients, floating bodies, mortar non-penetration conditions, etc. The exposition is divided into four parts, the first of which reviews appropriate facets of linear algebra, optimization, and analysis. The most important algorithms and optimality results are presented in the third part of the volume. The presentation is complete, including continuous formulation, discretization, decomposition, optimality results, and numerical experimen...

  2. Quaternionic contact Einstein structures and the quaternionic contact Yamabe problem

    Ivanov, Stefan; Vassilev, Dimiter

    2014-01-01

    A partial solution of the quaternionic contact Yamabe problem on the quaternionic sphere is given. It is shown that the torsion of the Biquard connection vanishes exactly when the trace-free part of the horizontal Ricci tensor of the Biquard connection is zero and this occurs precisely on 3-Sasakian manifolds. All conformal transformations sending the standard flat torsion-free quaternionic contact structure on the quaternionic Heisenberg group to a quaternionic contact structure with vanishing torsion of the Biquard connection are explicitly described. A "3-Hamiltonian form" of infinitesimal conformal automorphisms of quaternionic contact structures is presented.

  3. Bilateral contact problem with adhesion and damage

    Adel Aissaoui

    2014-05-01

    Full Text Available We study a mathematical problem describing the frictionless adhesive contact between a viscoelastic material with damage and a foundation. The adhesion process is modeled by a bonding field on the contact surface. The contact is bilateral and the tangential shear due to the bonding field is included. We establish a variational formulation for the problem and prove the existence and uniqueness of the solution. The existence of a unique weak solution for the problem is established using arguments of nonlinear evolution equations with monotone operators, a classical existence and uniqueness result for parabolic inequalities, and Banach's fixed point theorem.

  4. Radiofrequency contact currents: sensory responses and dosimetry

    Kavet, Robert; Tell, R.A.; Olsen, R.G.

    2014-01-01

    The process of setting science-based exposure standards (or guidelines) for radiofrequency (RF) contact current exposure has been disadvantaged by a lack of relevant data. The authors first review the essential features and results of the available studies and illustrate the apparent discrepancies among them. Then, they examine the manner in which current was administered in these studies and suggest as to how the physical relationship of a contacting finger to the current electrode may play a role in affecting sensory thresholds specific to those configurations. A major factor in this analysis relates to whether current density is uniformly distributed across the contact area or whether an electrode's 'edge effects' enhance currents with a net effect of decreasing apparent thresholds, when expressed as the bulk current entering a subject. For an exposure with a clear hazard potential, thresholds of human sensory response to RF currents require further investigation. (authors)

  5. [Current problems of deontology].

    Dimov, A S

    2010-01-01

    The scope of knowledge in medical ethics continues to extend. Deontology as a science needs systematization of the accumulated data. This review may give impetus to classification of problems pertaining to this important area of medical activity.

  6. Pulsed Current Static Electrical Contact Experiment

    Jones, Harry N; Neri, Jesse M; Boyer, Craig N; Cooper, Khershed P; Meger, Robert A

    2006-01-01

    .... The voltage developed across the interface is directly related to the contact temperature and pressure, the number of a-spots, the thermophysical and mechanical properties of the contacting materials...

  7. Perspectives on setting limits for RF contact currents: a commentary.

    Tell, Richard A; Tell, Christopher A

    2018-01-15

    Limits for exposure to radiofrequency (RF) contact currents are specified in the two dominant RF safety standards and guidelines developed by the Institute of Electrical and Electronics Engineers (IEEE) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). These limits are intended to prevent RF burns when contacting RF energized objects caused by high local tissue current densities. We explain what contact currents are and review some history of the relevant limits with an emphasis on so-called "touch" contacts, i.e., contact between a person and a contact current source during touch via a very small contact area. Contact current limits were originally set on the basis of controlling the specific absorption rate resulting from the current flowing through regions of small conductive cross section within the body, such as the wrist or ankle. More recently, contact currents have been based on thresholds of perceived heating. In the latest standard from the IEEE developed for NATO, contact currents have been based on two research studies in which thresholds for perception of thermal warmth or thermal pain have been measured. Importantly, these studies maximized conductive contact between the subject and the contact current source. This factor was found to dominate the response to heating wherein high resistance contact, such as from dry skin, can result in local heating many times that from a highly conductive contact. Other factors such as electrode size and shape, frequency of the current and the physical force associated with contact are found to introduce uncertainty in threshold values when comparing data across multiple studies. Relying on studies in which the contact current is minimized for a given threshold does not result in conservative protection limits. Future efforts to develop limits on contact currents should include consideration of (1) the basis for the limits (perception, pain, tissue damage); (2) understanding of the

  8. Unilateral contact problems variational methods and existence theorems

    Eck, Christof; Krbec, Miroslav

    2005-01-01

    The mathematical analysis of contact problems, with or without friction, is an area where progress depends heavily on the integration of pure and applied mathematics. This book presents the state of the art in the mathematical analysis of unilateral contact problems with friction, along with a major part of the analysis of dynamic contact problems without friction. Much of this monograph emerged from the authors'' research activities over the past 10 years and deals with an approach proven fruitful in many situations. Starting from thin estimates of possible solutions, this approach is based on an approximation of the problem and the proof of a moderate partial regularity of the solution to the approximate problem. This in turn makes use of the shift (or translation) technique - an important yet often overlooked tool for contact problems and other nonlinear problems with limited regularity. The authors pay careful attention to quantification and precise results to get optimal bounds in sufficient conditions f...

  9. Non-contact current and voltage sensor

    Carpenter, Gary D; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C; Schappert, Michael A

    2014-03-25

    A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing that contains the current and voltage sensors, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, or alternative a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

  10. Current contact device for a superconducting magnet coil

    Hieronymus, H.

    1987-01-01

    The invention concerns a current supply device for a superconducting magnet coil to be shortcircuited, with a separating device per coil end, which contains a fixed cooled contact and a moving contact connected to a power supply device and a mechanical actuating device for closing and opening the contacts. When closing the heated contact on to the cooled contact, relatively large quantities of heat can be transferred to the cooled contact and therefore to the connected superconducting coil end and can cause normal conduction there. The invention therefore provides that the mass ratio of the cooled contact to the moving contact is at least 5:1, preferably at least 10:1, and that the cooled contact part is provided, at the end away from the contact area, with means for increasing the area, for example cooling fins and is connected to the coil end has a thermal resistance between the contact area and the coil end of at least 0.2 k/W, preferably at least 0.5 k/W per 1000 A of current to be transmitted. (orig.) [de

  11. Mathematical Modeling of Contact Problems of Elasticity Theory with Continuous Unilateral Contact

    I. V. Stankevich

    2015-01-01

    Full Text Available The work [1] presents the formulation and numerical solution of the problem concerning the unilateral discrete contact interaction of an elastic body and a rigid half-space. However, many parts and components of engineering structures have a pronounced continuous contact within a given surface [2, 3]. In this paper we consider a special case of this option of contact interaction when, the elastic body of finite size, subjected to external forces, is based on a rigid half-space. Contact occurs through a dedicated contact surface, which in general can change their sizes.Developed to solve this problem, a numerical algorithm is a further adaptation and development of the approaches described in [1]. The paper shows results of solving the model problem of the elasticity theory with and without taking friction into account. In the latter case, were additionally obtained numerical data characterizing the convergence of the solution.

  12. Mechanisms of current flow in metal-semiconductor ohmic contacts

    Blank, T. V.; Gol'dberg, Yu. A.

    2007-01-01

    Published data on the properties of metal-semiconductor ohmic contacts and mechanisms of current flow in these contacts (thermionic emission, field emission, thermal-field emission, and also current flow through metal shunts) are reviewed. Theoretical dependences of the resistance of an ohmic contact on temperature and the charge-carrier concentration in a semiconductor were compared with experimental data on ohmic contacts to II-VI semiconductors (ZnSe, ZnO), III-V semiconductors (GaN, AlN, InN, GaAs, GaP, InP), Group IV semiconductors (SiC, diamond), and alloys of these semiconductors. In ohmic contacts based on lightly doped semiconductors, the main mechanism of current flow is thermionic emission with the metal-semiconductor potential barrier height equal to 0.1-0.2 eV. In ohmic contacts based on heavily doped semiconductors, the current flow is effected owing to the field emission, while the metal-semiconductor potential barrier height is equal to 0.3-0.5 eV. In alloyed In contacts to GaP and GaN, a mechanism of current flow that is not characteristic of Schottky diodes (current flow through metal shunts formed by deposition of metal atoms onto dislocations or other imperfections in semiconductors) is observed

  13. Critical current of Josephson contacts with accidental position of vortexes

    Fistul', M.V.

    1989-01-01

    Josephson contact critical current dependence on magnetic field under different concentrations of Abrikosov vortices (AV) in superconducting shores is found. Pinned vortex concentration as well as correlation in the vortex position can be determined by Josephson current dependence on magnetic field

  14. A dynamic contact problem between elasto-viscoplastic piezoelectric bodies

    Tedjani Hadj ammar

    2014-10-01

    Full Text Available We consider a dynamic contact problem with adhesion between two elastic-viscoplastic piezoelectric bodies. The contact is frictionless and is described with the normal compliance condition. We derive variational formulation for the model which is in the form of a system involving the displacement field, the electric potential field and the adhesion field. We prove the existence of a unique weak solution to the problem. The proof is based on arguments of nonlinear evolution equations with monotone operators, a classical existence and uniqueness result on parabolic inequalities, differential equations and fixed point arguments.

  15. Current voltage characteristics of composite superconductors with high contact resistance

    Akhmetov, A.A.; Baev, V.P.

    1984-01-01

    An experimental study has been made of current-voltage characteristics of composite superconductors with contact resistance between superconducting filaments and normal metal with high electrical conductivity. It is shown that stable resistive states exist in such conductors over a wide range of currents. The presence of resistive states is interpreted in terms of the resistive domain concept. The minimum and maximum currents of resistive states are found to be dependent on the electrical resistance of normal metal and magnetic field. (author)

  16. Solution of Contact Problems for Nonlinear Gao Beam and Obstacle

    J. Machalová

    2015-01-01

    Full Text Available Contact problem for a large deformed beam with an elastic obstacle is formulated, analyzed, and numerically solved. The beam model is governed by a nonlinear fourth-order differential equation developed by Gao, while the obstacle is considered as the elastic foundation of Winkler’s type in some distance under the beam. The problem is static without a friction and modeled either using Signorini conditions or by means of normal compliance contact conditions. The problems are then reformulated as optimal control problems which is useful both for theoretical aspects and for solution methods. Discretization is based on using the mixed finite element method with independent discretization and interpolations for foundation and beam elements. Numerical examples demonstrate usefulness of the presented solution method. Results for the nonlinear Gao beam are compared with results for the classical Euler-Bernoulli beam model.

  17. Analysis of a Unilateral Contact Problem with Normal Compliance

    Touzaline Arezki

    2014-06-01

    Full Text Available The paper deals with the study of a quasistatic unilateral contact problem between a nonlinear elastic body and a foundation. The contact is modelled with a normal compliance condition associated to unilateral constraint and the Coulomb's friction law. The adhesion between contact surfaces is taken into account and is modelled with a surface variable, the bonding field, whose evolution is described by a first-order differential equation. We establish a variational formulation of the mechanical problem and prove an existence and uniqueness result in the case where the coefficient of friction is bounded by a certain constant. The technique of the proof is based on arguments of time-dependent variational inequalities, differential equations and fixed-point theorem.

  18. Periodic Contact and Crack Problems in Plane Elasticity

    Krenk, Steen

    1976-01-01

    By use of singular integral equations it is demonstrated how some periodic contact and crack problems can be solved in closed form. The integral equation in question is the same which is encountered when dealing with mixed boundary conditions on a circle. As analytical evaluation of the solution ...... may be quite complicated attention is drawn to a numerical quadrature method...

  19. Current problems of radiation hygiene

    Krotkov, F.G.; Golikov, V.Ya.

    1980-01-01

    Present status of radiation hygiene is considered and prospects of its further development are outlined in connection with the expansion of atomic energy use for peaceful purposes. Transfer to the new system of irradiation level reglamentation which is recommended by ICRP presupposes further investigations and data acquisition. Necessity of data acquisition on the frequency of stochastic effects of the doses not exceeding 100 rem, substantiations of methodical approaches to the assessment of the collective radiation doses of large human population groups at low levels of personal irradiation, obtaining of reliable information on the contribution of different sources into collective radiation doses are pointed out. Further investigations on the problems of radiation safety of patients and also prediction assessment of the existing systems of radioactive waste disposal, forecasting and insurance of radioactive wastes, forecasting and insurance of radiation accidents, connected with the injection of radionuclides into the biosphere deserve special attention. Perspective directions of scientific investigations in the field of occupational radiation hygiene are poined out

  20. Approximate stresses in 2-D flat elastic contact fretting problems

    Urban, Michael Rene

    Fatigue results from the cyclic loading of a solid body. If the body subject to fatigue is in contact with another body and relative sliding motion occurs between these two bodies, then rubbing surface damage can accelerate fatigue failure. The acceleration of fatigue failure is especially important if the relative motion between the two bodies results in surface damage without excessive surface removal via wear. The situation just described is referred to as fretting fatigue. Understanding of fretting fatigue is greatly enhanced if the stress state associated with fretting can be characterized. For Hertzian contact, this can readily be done. Unfortunately, simple stress formulae are not available for flat body contact. The primary result of the present research is the development of a new, reasonably accurate, approximate closed form expression for 2-dimensional contact stresses which has been verified using finite element modeling. This expression is also combined with fracture mechanics to provide a simple method of determining when a crack is long enough to no longer be affected by the contact stress field. Lower bounds on fatigue life can then easily be calculated using fracture mechanics. This closed form expression can also be used to calculate crack propagation within the contact stress field. The problem of determining the cycles required to generate an initial crack and what to choose as an initial crack size is unresolved as it is in non-fretting fatigue.

  1. Current-voltage curves of gold quantum point contacts revisited

    Hansen, K.; Nielsen, S K.; Brandbyge, Mads

    2000-01-01

    We present measurements of current-voltage (I-V) curves on gold quantum point contacts (QPCs) with a conductance up to 4 G(0) (G(0) = 2e(2)/h is the conductance quantum) and voltages up to 2 V. The QPCs are formed between the gold tip of a scanning tunneling microscope and a Au(110) surface under...

  2. Current problems of marine pollution. Papers

    Dethlefsen, V.

    1993-01-01

    During the lecture meeting of the working committee for waste water problems of the German Fishery Association, papers were presented on current problems of waste pollution and on the potential effects of climate changes on the fishing industry. (EF) [de

  3. Mathematical Modeling of Contact Problems of Elasticity Theory with Unilateral Discrete Contact

    I. V. Stankevich

    2015-01-01

    Full Text Available Development and operation of modern machinery and latest technology require reliable estimates of the strength characteristics of the critical elements of structures and technological equipment under the impact of high-intensity thermomechanical loading, accompanied, as a rule, by complex contact interaction. Mathematical modeling of stress-strain state of such parts and components in the contact area, based on adequate mathematical models, modern numerical methods and efficient algorithms that implement the direct determination of displacement fields, strains and stresses, is the main tool that allows fast acquisition of data required for the calculations of strength and durability. The paper considers an algorithm for constructing the numerical solution of the contact problem of elasticity theory in relation to the body, which has an obvious one-sided discrete contact interaction with an elastic half-space. The proposed algorithm is specially designed to have a correction of the tangential forces at discrete contact points, allowing us to achieve sufficiently accurate implementation of the adopted law of friction. The algorithm is embedded in a general finite element technology, with which the application code is generated. Numerical study of discrete unilateral contact interaction of an elastic plate and a rigid half-space showed a high efficiency of the developed algorithm and the application code that implements it.

  4. Testing and Modeling of Contact Problems in Resistance Welding

    Song, Quanfeng

    together two or three cylindrical parts as well as disc-ring pairs of dissimilar metals. The tests have demonstrated the effectiveness of the model. A theoretical and experimental study is performed on the contact resistance aiming at a more reliable model for numerical simulation of resistance welding......As a part of the efforts towards a professional and reliable numerical tool for resistance welding engineers, this Ph.D. project is dedicated to refining the numerical models related to the interface behavior. An FE algorithm for the contact problems in resistance welding has been developed...... for the formulation, and the interfaces are treated in a symmetric pattern. The frictional sliding contact is also solved employing the constant friction model. The algorithm is incorporated into the finite element code. Verification is carried out in some numerical tests as well as experiments such as upsetting...

  5. THE CONTROL VARIATIONAL METHOD FOR ELASTIC CONTACT PROBLEMS

    Mircea Sofonea

    2010-07-01

    Full Text Available We consider a multivalued equation of the form Ay + F(y = fin a real Hilbert space, where A is a linear operator and F represents the (Clarke subdifferential of some function. We prove existence and uniqueness results of the solution by using the control variational method. The main idea in this method is to minimize the energy functional associated to the nonlinear equation by arguments of optimal control theory. Then we consider a general mathematical model describing the contact between a linearly elastic body and an obstacle which leads to a variational formulation as above, for the displacement field. We apply the abstract existence and uniqueness results to prove the unique weak solvability of the corresponding contact problem. Finally, we present examples of contact and friction laws for which our results work.

  6. Current simulation of symmetric contacts on CdTe

    Ruzin, A.

    2011-01-01

    This article presents the calculated current-voltage characteristics of symmetric Metal-Semiconductor-Metal configurations for Schottky, Ohmic, and injecting-Ohmic contacts on high resistivity CdTe. The results clearly demonstrate that in the wide band-gap, semi-insulating semiconductors, such as high resistivity CdTe, the linearity of the I-V curves cannot be considered a proof of the ohmicity of the contacts. It is shown that the linear I-V curves are expected for a wide range of contact barriers. Furthermore, the slope of these linear curves is governed by the barrier height, rather than the bulk doping concentration. Therefore the deduction of bulk's resistivity from the I-V curves may be false.

  7. Current simulation of symmetric contacts on CdTe

    Ruzin, A., E-mail: aruzin@post.tau.ac.il [School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv (Israel)

    2011-12-01

    This article presents the calculated current-voltage characteristics of symmetric Metal-Semiconductor-Metal configurations for Schottky, Ohmic, and injecting-Ohmic contacts on high resistivity CdTe. The results clearly demonstrate that in the wide band-gap, semi-insulating semiconductors, such as high resistivity CdTe, the linearity of the I-V curves cannot be considered a proof of the ohmicity of the contacts. It is shown that the linear I-V curves are expected for a wide range of contact barriers. Furthermore, the slope of these linear curves is governed by the barrier height, rather than the bulk doping concentration. Therefore the deduction of bulk's resistivity from the I-V curves may be false.

  8. Simulation of unilateral contact problems departing from the classical boundary problems

    Frey, S.L.; Sampaio, R.; Gama, R.M.S. da.

    1989-08-01

    A numerical algorithm is proposed for simulating unilateral contact problems under the classical elasticity point of view. This simple algorithm may be employed by engineers with a minimum knowledge on classical elasticity. (A.C.A.S.) [pt

  9. On topological derivatives for contact problems in elasticity

    Giusti, S.M.; Sokolowski, S.; Stebel, Jan

    2015-01-01

    Roč. 165, č. 1 (2015), s. 279-294 ISSN 0022-3239 R&D Projects: GA ČR GA201/09/0917 Institutional support: RVO:67985840 Keywords : topological derivative * static frictionless contact problem * asymptotic analysis Subject RIV: BA - General Mathematics Impact factor: 1.160, year: 2015 http://link.springer.com/article/10.1007%2Fs10957-014-0594-7

  10. Alternative current source based Schottky contact with additional electric field

    Mamedov, R. K.; Aslanova, A. R.

    2017-07-01

    Additional electric field (AEF) in the Schottky contacts (SC) that covered the peripheral contact region wide and the complete contact region narrow (as TMBS diode) SC. Under the influence of AEF is a redistribution of free electrons produced at certain temperatures of the semiconductor, and is formed the space charge region (SCR). As a result of the superposition of the electric fields SCR and AEF occurs the resulting electric field (REF). The REF is distributed along a straight line perpendicular to the contact surface, so that its intensity (and potential) has a minimum value on the metal surface and the maximum value at a great distance from the metal surface deep into the SCR. Under the influence of AEF as a sided force the metal becomes negative pole and semiconductor - positive pole, therefore, SC with AEF becomes an alternative current source (ACS). The Ni-nSi SC with different diameters (20-1000 μm) under the influence of the AEF as sided force have become ACS with electromotive force in the order of 0.1-1.0 mV, which are generated the electric current in the range of 10-9-10-7 A, flowing through the external resistance 1000 Ohm.

  11. Numerical algorithms for contact problems in linear elastostatics

    Barbosa, H.J.C.; Feijoo, R.A.

    1984-01-01

    In this work contact problems in linear elasticity are analysed by means of Finite Elements and Mathematical Programming Techniques. The principle of virtual work leads in this case to a variational inequality which in turn is equivalent, for Hookean materials and infinitesimal strains, to the minimization of the total potential energy over the set of all admissible virtual displacements. The use of Gauss-Seidel algorithm with relaxation and projection and also Lemke's algorithm and Uzawa's algorithm for solving the minimization problem is discussed. Finally numerical examples are presented. (Author) [pt

  12. Inverse source problems for eddy current equations

    Rodríguez, Ana Alonso; Valli, Alberto; Camaño, Jessika

    2012-01-01

    We study the inverse source problem for the eddy current approximation of Maxwell equations. As for the full system of Maxwell equations, we show that a volume current source cannot be uniquely identified by knowledge of the tangential components of the electromagnetic fields on the boundary, and we characterize the space of non-radiating sources. On the other hand, we prove that the inverse source problem has a unique solution if the source is supported on the boundary of a subdomain or if it is the sum of a finite number of dipoles. We address the applicability of this result for the localization of brain activity from electroencephalography and magnetoencephalography measurements. (paper)

  13. Comparison between FEBio and Abaqus for biphasic contact problems.

    Meng, Qingen; Jin, Zhongmin; Fisher, John; Wilcox, Ruth

    2013-09-01

    Articular cartilage plays an important role in the function of diarthrodial joints. Computational methods have been used to study the biphasic mechanics of cartilage, and Abaqus has been one of the most widely used commercial software packages for this purpose. A newly developed open-source finite element solver, FEBio, has been developed specifically for biomechanical applications. The aim of this study was to undertake a direct comparison between FEBio and Abaqus for some practical contact problems involving cartilage. Three model types, representing a porous flat-ended indentation test, a spherical-ended indentation test, and a conceptual natural joint contact model, were compared. In addition, a parameter sensitivity study was also performed for the spherical-ended indentation test to investigate the effects of changes in the input material properties on the model outputs, using both FEBio and Abaqus. Excellent agreement was found between FEBio and Abaqus for all of the model types and across the range of material properties that were investigated.

  14. Computational methods in calculating superconducting current problems

    Brown, David John, II

    Various computational problems in treating superconducting currents are examined. First, field inversion in spatial Fourier transform space is reviewed to obtain both one-dimensional transport currents flowing down a long thin tape, and a localized two-dimensional current. The problems associated with spatial high-frequency noise, created by finite resolution and experimental equipment, are presented, and resolved with a smooth Gaussian cutoff in spatial frequency space. Convergence of the Green's functions for the one-dimensional transport current densities is discussed, and particular attention is devoted to the negative effects of performing discrete Fourier transforms alone on fields asymptotically dropping like 1/r. Results of imaging simulated current densities are favorably compared to the original distributions after the resulting magnetic fields undergo the imaging procedure. The behavior of high-frequency spatial noise, and the behavior of the fields with a 1/r asymptote in the imaging procedure in our simulations is analyzed, and compared to the treatment of these phenomena in the published literature. Next, we examine calculation of Mathieu and spheroidal wave functions, solutions to the wave equation in elliptical cylindrical and oblate and prolate spheroidal coordinates, respectively. These functions are also solutions to Schrodinger's equations with certain potential wells, and are useful in solving time-varying superconducting problems. The Mathieu functions are Fourier expanded, and the spheroidal functions expanded in associated Legendre polynomials to convert the defining differential equations to recursion relations. The infinite number of linear recursion equations is converted to an infinite matrix, multiplied by a vector of expansion coefficients, thus becoming an eigenvalue problem. The eigenvalue problem is solved with root solvers, and the eigenvector problem is solved using a Jacobi-type iteration method, after preconditioning the

  15. Current problems in chemical track etching

    Somogyi, G.

    1984-01-01

    A schematic survey is given on the current relevant problems of the etching (or revelation) of multi-track and single-track events in dielectric solids. Some aspects of the research trends and possible new applications of the effects observable here, are also considered. (author)

  16. Solutions of dissimilar material singularity and contact problems

    Yang, Y.

    2003-09-01

    Due to the mismatch of the material properties of joined components, after a homogeneous temperature change or under a mechanical loading, very high stresses occur near the intersection of the interface and the outer surface, or near the intersection of two interfaces. For most material combinations and joint geometries, there exists even a stress singularity. These high stresses may cause fracture of the joint. The investigation of the stress situation near the singular point, therefore, is of great interest. Especially, the relationship between the singular stress exponent, the material data and joint geometry is important for choosing a suitable material combination and joint geometry. In this work, the singular stress field is described analytically in case of the joint having a real and a complex eigenvalue. Solutions of different singularity problems are given, which are two dissimilar materials joint with free edges; dissimilar materials joint with edge tractions; joint with interface corner; joint with a given displacement at one edge; cracks in dissimilar materials joint; contact problem in dissimilar materials and logarithmic stress singularity. For an arbitrary joint geometry and material combination, the stress singular exponent, the angular function and the regular stress term can be calculated analytically. The stress intensity factors for a finite joint can be determined applying numerical methods, e.g. the finite element method (FEM). The method to determine more than one stress intensity factor is presented. The characteristics of the eigenvalues and the stress intensity factors are shown for different joint conditions. (orig.)

  17. Existence for viscoplastic contact with Coulomb friction problems

    Amina Amassad

    2002-01-01

    frictional contact between an elastic-viscoplastic body and a rigid obstacle. We model the frictional contact both by a Tresca's friction law and a regularized Coulomb's law. We assume, in a first part, that the contact is bilateral and that no separation takes place. In a second part, we consider the Signorini unilateral contact conditions. Proofs are based on a time-discretization method, Banach and Schauder fixed point theorems.

  18. Current knowledge on biomarkers for contact sensitization and allergic contact dermatitis

    Koppes, Sjors A.; Engebretsen, Kristiane A.; Agner, Tove; Angelova-Fischer, Irena; Berents, Teresa; Brandner, Johanna; Brans, Richard; Clausen, Maja-Lisa; Hummler, Edith; Jakasa, Ivone; Jurakić-Tončic, Ružica; John, Swen M.; Khnykin, Denis; Molin, Sonja; Holm, Jan O.; Suomela, Sari; Thierse, Hermann-Josef; Kezic, Sanja; Martin, Stefan F.; Thyssen, Jacob P.

    2017-01-01

    Contact sensitization is common and affects up to 20% of the general population. The clinical manifestation of contact sensitization is allergic contact dermatitis. This is a clinical expression that is sometimes difficult to distinguish from other types of dermatitis, for example irritant and

  19. AIRBORNE CONTACT DERMATITIS – CURRENT PERSPECTIVES IN ETIOPATHOGENESIS AND MANAGEMENT

    Handa, Sanjeev; De, Dipankar; Mahajan, Rahul

    2011-01-01

    The increasing recognition of occupational origin of airborne contact dermatitis has brought the focus on the variety of irritants, which can present with this typical morphological picture. At the same time, airborne allergic contact dermatitis secondary to plant antigens, especially to Compositae family, continues to be rampant in many parts of the world, especially in the Indian subcontinent. The recognition of the contactant may be difficult to ascertain and the treatment may be even more difficult. The present review focuses on the epidemiological, clinical and therapeutic issues in airborne contact dermatitis. PMID:22345774

  20. Research on the Problem of Spur Gear Teeth Contact in the Car Gear Box

    Viktor Skrickij

    2011-04-01

    Full Text Available The article presents research on the problem of two gear contact in the car gearbox. Contact stiffness is evaluated for the whole period of mesh. Also, contact stresses are evaluated in the contact place. The presented method can be used for calculating spur gear.Article in Lithuanian

  1. Current knowledge on biomarkers for contact sensitization and allergic contact dermatitis.

    Koppes, Sjors A; Engebretsen, Kristiane A; Agner, Tove; Angelova-Fischer, Irena; Berents, Teresa; Brandner, Johanna; Brans, Richard; Clausen, Maja-Lisa; Hummler, Edith; Jakasa, Ivone; Jurakić-Tončic, Ružica; John, Swen M; Khnykin, Denis; Molin, Sonja; Holm, Jan O; Suomela, Sari; Thierse, Hermann-Josef; Kezic, Sanja; Martin, Stefan F; Thyssen, Jacob P

    2017-07-01

    Contact sensitization is common and affects up to 20% of the general population. The clinical manifestation of contact sensitization is allergic contact dermatitis. This is a clinical expression that is sometimes difficult to distinguish from other types of dermatitis, for example irritant and atopic dermatitis. Several studies have examined the pathogenesis and severity of allergic contact dermatitis by measuring the absence or presence of various biomarkers. In this review, we provide a non-systematic overview of biomarkers that have been studied in allergic contact dermatitis. These include genetic variations and mutations, inflammatory mediators, alarmins, proteases, immunoproteomics, lipids, natural moisturizing factors, tight junctions, and antimicrobial peptides. We conclude that, despite the enormous amount of data, convincing specific biomarkers for allergic contact dermatitis are yet to be described. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Current knowledge on biomarkers for contact sensitization and allergic contact dermatitis

    Koppes, Sjors A.; Engebretsen, Kristiane A.; Agner, Tove

    2017-01-01

    Contact sensitization is common and affects up to 20% of the general population. The clinical manifestation of contact sensitization is allergic contact dermatitis. This is a clinical expression that is sometimes difficult to distinguish from other types of dermatitis, for example irritant...... and atopic dermatitis. Several studies have examined the pathogenesis and severity of allergic contact dermatitis by measuring the absence or presence of various biomarkers. In this review, we provide a non-systematic overview of biomarkers that have been studied in allergic contact dermatitis. These include...... genetic variations and mutations, inflammatory mediators, alarmins, proteases, immunoproteomics, lipids, natural moisturizing factors, tight junctions, and antimicrobial peptides. We conclude that, despite the enormous amount of data, convincing specific biomarkers for allergic contact dermatitis are yet...

  3. [Problems with current hypertension definition in children].

    Peco-Antić, Amira

    2008-01-01

    The Task Force data have added immeasurably to our understanding of the normal distribution of blood pressure in children. However, the manner in which arterial hypertension is defined in children is not without problems. The main problem is that the current definition of hypertension in children is not based on the end-organ damage assessment, but on the blood pressure height-related percentile distribution of healthy reference population. This could be overcome by introducing the relationship of blood pressure values with sensitive markers of hypertensive sequelae (such as carotid intimal-medial thickness, left ventricle mass index, retinal arteriolar narrowing and arteriovenous nicking as well as microalbumin urinary excretion) to define better the specific blood pressure values with outcomes. Furthermore, the current definition of hypertension based on the demographic and clinical characteristics of the reference population does not consider the normal evolution of reference population, as well as its ethnic differences. In addition, being based on the single occasion measurement in quite position it does not account for the possibility of transient, stress induced elevations in blood pressure known as white coat hypertension. Therefore, incorporation ambulatory 24 h blood pressure data into the definition of arterial hypertension in children may increase the definition reliability for clinical decision - making, although for such reliability the paediatric normative ambulatory blood pressure data should be improved.

  4. Influence of Stress Shape Function on Analysis of Contact Problem Using Hybrid Photoelasticity

    Shin, Dongchul; Hawong, Jaisug

    2013-01-01

    In this research, a study on stress shape functions was conducted to analyze the contact stress problem by using a hybrid photoelasticity. Because the contact stress problem is generally solved as a half-plane problem, the relationship between two analytical stress functions, which are compositions of the Airy stress function, was similar to one of the crack problem. However, this relationship in itself could not be used to solve the contact stress problem (especially one with singular points). Therefore, to analyze the contact stress problem more correctly, stress shape functions based on the condition of two contact end points had to be considered in the form of these two analytical stress functions. The four types of stress shape functions were related to the stress singularities at the two contact end points. Among them, the primary two types used for the analysis of an O-ring were selected, and their validities were verified in this work

  5. The steady-state tangential contact problem for a falling drop type of contact area on corrugated rail by simplified theory of rolling contact

    Piotrowski, Jerzy

    1991-10-01

    Investigation of contact mechanical nonlinearities of a mathematical model of corrugation revealed that the typical shape of contact patch resembles a falling drop of water. A contact patch of that shape was approximated with a figure composed of two parts of ellipses with different eccentricities. The contact pressure distribution was assumed as a smoothing ensemble of two paraboloidal distributions. The description of a general case of double half elliptical contact area was given but a special case of double half elliptical contact is more interesting as it possesses some Hertzian properties. It was shown how three geometrical parameters of double half elliptical contact can be chosen when actual, non-Hertzian contact is known. A linear theory was written which indicates that the lateral vibrations of the rail may be excited only due to shape variation on corrugation even if any other cause for these vibrations does not exist. For nonlinear theory a computer program, based on FASTSIM algorithm by Kalker, was written. The aim is to calculate the creep forces and frictional power density distribution over the contact area. Also, a graphic program visualizing the solution was written. Numerical results are not provided; unattended and unsolved problems relevant for this type of contact are listed.

  6. A finite-element model for moving contact line problems in immiscible two-phase flow

    Kucala, Alec

    2017-11-01

    Accurate modeling of moving contact line (MCL) problems is imperative in predicting capillary pressure vs. saturation curves, permeability, and preferential flow paths for a variety of applications, including geological carbon storage (GCS) and enhanced oil recovery (EOR). The macroscale movement of the contact line is dependent on the molecular interactions occurring at the three-phase interface, however most MCL problems require resolution at the meso- and macro-scale. A phenomenological model must be developed to account for the microscale interactions, as resolving both the macro- and micro-scale would render most problems computationally intractable. Here, a model for the moving contact line is presented as a weak forcing term in the Navier-Stokes equation and applied directly at the location of the three-phase interface point. The moving interface is tracked with the level set method and discretized using the conformal decomposition finite element method (CDFEM), allowing for the surface tension and the wetting model to be computed at the exact interface location. A variety of verification test cases for simple two- and three-dimensional geometries are presented to validate the current MCL model, which can exhibit grid independence when a proper scaling for the slip length is chosen. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.

  7. Nonsmooth Newton method for Fischer function reformulation of contact force problems for interactive rigid body simulation

    Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny

    2009-01-01

    contact response. In this paper, we present a new approach to contact force determination. We reformulate the contact force problem as a nonlinear root search problem, using a Fischer function. We solve this problem using a generalized Newton method. Our new Fischer - Newton method shows improved...... qualities for specific configurations where the most widespread alternative, the Projected Gauss-Seidel method, fails. Experiments show superior convergence properties of the exact Fischer - Newton method....

  8. Techniques for contact and contact with friction problems; Tecnicas para problemas de contacto y contacto con friccion

    Velandia Arana, Gonzalo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    Different numerical techniques are presented based in the finite element method to obtain numerical solutions to contact and contact with friction problems between solid bodies, and compared between each other. [Espanol] Se presentan diferentes tecnicas numericas basadas en el metodo de elementos finitos para la obtencion de soluciones numericas de problemas de contacto y contacto con friccion entre cuerpos solidos, y se comparan entre si.

  9. Techniques for contact and contact with friction problems; Tecnicas para problemas de contacto y contacto con friccion

    Velandia Arana, Gonzalo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    Different numerical techniques are presented based in the finite element method to obtain numerical solutions to contact and contact with friction problems between solid bodies, and compared between each other. [Espanol] Se presentan diferentes tecnicas numericas basadas en el metodo de elementos finitos para la obtencion de soluciones numericas de problemas de contacto y contacto con friccion entre cuerpos solidos, y se comparan entre si.

  10. A frictional contact problem for an electro-viscoelastic body

    Mircea Sofonea

    2007-12-01

    Full Text Available A mathematical model which describes the quasistatic frictional contact between a piezoelectric body and a deformable conductive foundation is studied. A nonlinear electro-viscoelastic constitutive law is used to model the piezoelectric material. Contact is described with the normal compliance condition, a version of Coulomb's law of dry friction, and a regularized electrical conductivity condition. A variational formulation of the model, in the form of a coupled system for the displacements and the electric potential, is derived. The existence of a unique weak solution of the model is established under a smallness assumption on the surface conductance. The proof is based on arguments of evolutionary variational inequalities and fixed points of operators.

  11. Static semicoercive normal compliance contact problem with limited interpenetration

    Jarušek, Jiří

    2015-01-01

    Roč. 66, č. 5 (2015), s. 2161-2172 ISSN 0044-2275 R&D Projects: GA ČR(CZ) GAP201/12/0671 Institutional support: RVO:67985840 Keywords : contact * limited interpenetration * friction Subject RIV: BA - General Mathematics Impact factor: 1.560, year: 2015 http://link.springer.com/article/10.1007%2Fs00033-015-0539-5

  12. Current Enhancement with Contact-Area-Limited Doping for Bottom-Gate, Bottom-Contact Organic Thin-Film Transistors

    Noda, Kei; Wakatsuki, Yusuke; Yamagishi, Yuji; Wada, Yasuo; Toyabe, Toru; Matsushige, Kazumi

    2013-02-01

    The current enhancement mechanism in contact-area-limited doping for bottom-gate, bottom-contact (BGBC) p-channel organic thin-film transistors (OTFTs) was investigated both by simulation and experiment. Simulation results suggest that carrier shortage and large potential drop occur in the source-electrode/channel interface region in a conventional BGBC OTFT during operation, which results in a decrease in the effective field-effect mobility. These phenomena are attributed to the low carrier concentration of active semiconductor layers in OTFTs and can be alleviated by contact-area-limited doping, where highly doped layers are prepared over source-drain electrodes. According to two-dimensional current distribution obtained from the device simulation, a current flow from the source electrode to the channel region via highly doped layers is generated in addition to the direct carrier injection from the source electrode to the channel, leading to the enhancement of the drain current and effective field-effect mobility. The expected current enhancement mechanism in contact-area-limited doping was experimentally confirmed in typical α-sexithiophene (α-6T) BGBC thin-film transistors.

  13. Contact allergy and allergic contact dermatitis in children - a review of current data

    Simonsen, Anne Birgitte; Deleuran, Mette; Johansen, Jeanne Duus

    2011-01-01

    Allergic contact dermatitis (ACD) in children was previously considered to be a rare occurrence. However, the growing number of case reports and cross-sectional studies through the past three decades indicate that ACD is, in fact, a highly relevant diagnosis in children. Furthermore, the frequency...... reactions. Children with atopic dermatitis are as frequently sensitized as children with no history of atopic dermatitis, and there are no differences associated with sex. Children and adults can be tested with equal concentrations of patch test allergens. Our findings may support the notion...

  14. Mixed Finite Element Method for Static and Dynamic Contact Problems with Friction and Initial Gaps

    Lanhao Zhao

    2014-01-01

    Full Text Available A novel mixed finite element method is proposed for static and dynamic contact problems with friction and initial gaps. Based on the characteristic of local nonlinearity for the problem, the system of forces acting on the contactor is divided into two parts: external forces and contact forces. The displacement of structure is chosen as the basic variable and the nodal contact force in contact region under local coordinate system is selected as the iteration variable to confine the nonlinear iteration process in the potential contact surface which is more numerically efficient. In this way, the sophisticated contact nonlinearity is revealed by the variety of the contact forces which are determined by the external load and the contact state stick, slip, or separation. Moreover, in the case of multibody contact problem, the flexibility matrix is symmetric and sparse; thus, the iterative procedure becomes easily carried out and much more economical. In the paper, both the finite element formulations and the iteration process are given in detail for static and dynamic contact problems. Four examples are included to demonstrate the accuracy and applicability of the presented method.

  15. Current-induced dynamics in carbon atomic contacts

    Lu, Jing Tao; Gunst, Tue; Brandbyge, Mads

    2011-01-01

    voltage, which can be used to explore current-induced vibrational instabilities due the NC/BP forces. Furthermore, using tight-binding and the Brenner potential we illustrate how Langevin-type molecular-dynamics calculations including the Joule heating effect for the carbon-chain systems can be performed...... be used to explore current-induced dynamics and instabilities. We find instabilities at experimentally relevant bias and gate voltages for the carbon-chain system. © 2011 Lü et al....... carbon chain connecting electrically gated graphene electrodes. This illustrates how the device stability can be predicted solely from the modes obtained from the Langevin equation, including the current-induced forces. We point out that the gate offers control of the current, independent of the bias...

  16. Contact problem for a composite material with nacre inspired microstructure

    Berinskii, Igor; Ryvkin, Michael; Aboudi, Jacob

    2017-12-01

    Bi-material composites with nacre inspired brick and mortar microstructures, characterized by stiff elements of one phase with high aspect ratio separated by thin layers of the second one, are considered. Such microstructure is proved to provide an efficient solution for the problem of a crack arrest. However, contrary to the case of a homogeneous material, an external pressure, applied to a part of the composite boundary, can cause significant tensile stresses which increase the danger of crack nucleation. Investigation of the influence of microstructure parameters on the magnitude of tensile stresses is performed by means of the classical Flamant-like problem of an orthotropic half-plane subjected to a normal external distributed loading. Adequate analysis of this problem represents a serious computational task due to the geometry of the considered layout and the high contrast between the composite constituents. This difficulty is presently circumvented by deriving a micro-to-macro analysis in the framework of which an analytical solution of the auxiliary elasticity problem, followed by the discrete Fourier transform and the higher-order theory are employed. As a result, full scale continuum modeling of both composite constituents without employing any simplifying assumptions is presented. In the framework of the present proposed modeling, the influence of stiff elements aspect ratio on the overall stress distribution is demonstrated.

  17. Current problems in the weak interactions

    Pais, A.

    1977-01-01

    Some reasons are discussed showing why the recent SU(2) x U(1) gauge theory of weak and electromagnetic interactions is not a complete theory of these interactions, Lepton theory, charm, and the CP problem are considered. 60 references

  18. Current problems of nuclear arms: some options

    Bocharov, I.F.

    1992-01-01

    Possible solutions of certain problems of the soviet nuclear weapons resulting from spontaneously changing military-political situation and social-economical living conditions on geostrategical space of the former USSR are discussed. Reliable stabilization of military-political situation on the former USSR territory is required for solving the above problems, which in its turn will possibly require active efforts of the international community. The idea on creation the Committee on non-prolifiration by the UN Security Council is proposed

  19. Current problems in (n,2n) reactions

    Cindro, N; Frehaut, J

    1975-01-01

    Two kinds of problems related to (n,2n) reactions are briefly discussed. The first one is the understanding of the reaction mechanism. The nucleus evaporation formulas overestimate the experimental values of the cross sections. This difference can be accounted for either by reestimating the relative values of GAMMA sub(..gamma..) and GAMMA sub(n) or by adding nonequilibrium process contributions. The second problem is the Csikai-Petoe effect. A more extensive analysis of the data shows that they are not in agreement with its predictions.

  20. Current problems in (n,2n) reactions

    Cindro, N.; Frehaut, J.

    1975-01-01

    Two kinds of problems related to (n,2n) reactions are briefly discussed. The first one is the understanding of the reaction mechanism. The nucleus evaporation formulas overestimate the experimental values of the cross sections. This difference can be accounted for either by reestimating the relative values of GAMMA sub(γ) and GAMMA sub(n) or by adding nonequilibrium process contributions. The second problem is the Csikai-Petoe effect. A more extensive analysis of the data shows that they are not in agreement with its predictions [fr

  1. Current problems of Bulgarian nuclear power

    Luk'yanov, A.A.; Vapirev, E.I.

    1996-01-01

    The main unsolved problems of Bulgarian nuclear power industry now are: a serious trouble that the WWER-440 units will have to be phased out before the end of their projected life since they do not meet contemporary safety requirements; heavy economic difficulties with the construction of the new NPP 'Belene'; accumulation of a considerable amount of spent fuel because of its interrupted export to Russia

  2. Current enhancement in crystalline silicon photovoltaic by low-cost nickel silicide back contact

    Bahabry, R. R.; Gumus, A.; Kutbee, A. T.; Wehbe, N.; Ahmed, S. M.; Ghoneim, M. T.; Lee, K. -T.; Rogers, J. A.; Hussain, M. M.

    2016-01-01

    We report short circuit current (Jsc) enhancement in crystalline silicon (C-Si) photovoltaic (PV) using low-cost Ohmic contact engineering by integration of Nickel mono-silicide (NiSi) for back contact metallization as an alternative to the status quo of using expensive screen printed silver (Ag). We show 2.6 mA/cm2 enhancement in the short circuit current (Jsc) and 1.2 % increment in the efficiency by improving the current collection due to the low specific contact resistance of the NiSi on the heavily Boron (B) doped Silicon (Si) interface.

  3. Current enhancement in crystalline silicon photovoltaic by low-cost nickel silicide back contact

    Bahabry, R. R.

    2016-11-30

    We report short circuit current (Jsc) enhancement in crystalline silicon (C-Si) photovoltaic (PV) using low-cost Ohmic contact engineering by integration of Nickel mono-silicide (NiSi) for back contact metallization as an alternative to the status quo of using expensive screen printed silver (Ag). We show 2.6 mA/cm2 enhancement in the short circuit current (Jsc) and 1.2 % increment in the efficiency by improving the current collection due to the low specific contact resistance of the NiSi on the heavily Boron (B) doped Silicon (Si) interface.

  4. A frictional contact problem with damage and adhesion for an electro elastic-viscoplastic body

    Adel Aissaoui

    2014-01-01

    Full Text Available We consider a quasistatic frictional contact problem for an electro elastic-viscopalastic body with damage and adhestion. The contact is modelled with normal compliance. The adhesion of the contact surfaces is taken into account and modelled by a surface variable. We derive variational formulation for the model which is in the form of a system involving the displacement field, the electric potential field, the damage field and the adhesion field. We prove the existence of a unique weak solution to the problem. The proof is based on arguments of time-dependent variational inequalities, parabolic inequalities, differential equations and fixed point.

  5. [Current quality management situation and administration countermeasure study of enterprises marketing corneal contact lens].

    Liu, Yungui; Yao, Ying; Shangguan, Shihao; Gu, Qun; Gao, Wuming; Chen, Yaoshui

    2014-05-01

    Study the current quality management situation of enterprises marketing corneal contact lens via systemic investigations and explore effective administration countermeasures in the future. The quality management indicators of sixty-two corneal contact lens marketing enterprises in Xuhui district of Shanghai were systematically investigated and enterprises of different operation models was compared and analyzed. Wholesale enterprises and retail chain enterprises are apparently better than independent enterprises almost in all facets. Facilitate market accession of corneal contact lens marketing enterprises, encourage the business model of retail chain, enhance supervision of corneal contact lens marketing enterprises, especially independent franchisors.

  6. Food irradiation: current problems and future potential

    Kilcast, D.

    1995-01-01

    Food irradiation is one of a set of processing technologies that can be used to increase the microbiological safety and shelf-life of a wide range of foods. Ionizing radiation is used to generate highly active chemical species within the food, which react with DNA. Under normal usage conditions, the food receives a pasteurizing treatment that gives a valuable reduction in common food-spoilage organisms and food pathogens. This review describes how the process is used in practice, including the benefits and limitations. The nature of changes to food components are outlined, together with the development of practical detection methods that utilize these changes. The legislative position of food irradiation is outlined, with the specific example of the introduction of the technology within the UK. The reasons for the slow uptake in the use of the technology are discussed, and the problem of consumer acceptance is addressed. (author)

  7. Neurocysticercosis: Diagnostic problems & current therapeutic strategies

    Vedantam Rajshekhar

    2016-01-01

    Full Text Available Neurocysticercosis (NCC is the most common single cause of seizures/epilepsy in India and several other endemic countries throughout the world. It is also the most common parasitic disease of the brain caused by the cestode Taenia solium or pork tapeworm. The diagnosis of NCC and the tapeworm carrier (taeniasis can be relatively inaccessible and expensive for most of the patients. In spite of the introduction of several new immunological tests, neuroimaging remains the main diagnostic test for NCC. The treatment of NCC is also mired in controversy although, there is emerging evidence that albendazole (a cysticidal drug may be beneficial for patients by reducing the number of seizures and hastening the resolution of live cysts. Currently, there are several diagnostic and management issues which remain unresolved. This review will highlight some of these issues.

  8. Neurocysticercosis: Diagnostic problems & current therapeutic strategies

    Rajshekhar, Vedantam

    2016-01-01

    Neurocysticercosis (NCC) is the most common single cause of seizures/epilepsy in India and several other endemic countries throughout the world. It is also the most common parasitic disease of the brain caused by the cestode Taenia solium or pork tapeworm. The diagnosis of NCC and the tapeworm carrier (taeniasis) can be relatively inaccessible and expensive for most of the patients. In spite of the introduction of several new immunological tests, neuroimaging remains the main diagnostic test for NCC. The treatment of NCC is also mired in controversy although, there is emerging evidence that albendazole (a cysticidal drug) may be beneficial for patients by reducing the number of seizures and hastening the resolution of live cysts. Currently, there are several diagnostic and management issues which remain unresolved. This review will highlight some of these issues. PMID:28139530

  9. Direct-Current Forced Interruption and Breaking Performance of Spiral-Type Contacts in Aero Applications

    Wenlei Huo

    2017-05-01

    Full Text Available This paper analyses the transient characteristics and breaking performance of direct-current (DC forced-interruption vacuum interrupters in 270 V power-supply systems. Three stages are identified in forced interruption: the DC-arcing stage, current-commutation stage, and voltage-recovery stage. During the current-commutation stage, the reverse peak-current coefficient k, which is a key design factor, is used to calculate the rate of current at zero-crossing (di/dt. MATLAB/Simulink simulation models are established to obtain the transient characteristics influenced by the forced-commutation branch parameters and the coefficient k. To study the breaking performance of spiral-type contacts, experiments are conducted for different contact materials and arcing times for currents less than 3.5 kA. During the DC-arcing stage, a locally intensive burning arc is observed in the CuW80 contact; however, it is not observed in the CuCr50 contact. On examining the re-ignition interruption results of the CuW80 contact, the intensive burning arc is found to be positioned within a possible re-ignition region. When the arcing time is longer than 1 ms, the intensive burning arc occurs and affects the breaking performance of the spiral-type contacts. If the DC-arcing stage is prolonged, the total arcing energy increases, which leads to a lower breaking capacity.

  10. Current problems in Russian-Latvian relations

    Mezhevich Nikolay

    2013-09-01

    Full Text Available Current relations between Russia and Latvia are still influenced by a series of mutual claims that appeared after the demise of the USSR. Latvia — as well as Estonia and Lithuania — is both an EU and NATO member state. However, unlike the above mentioned countries, its relations with Russia are developing at a more pragmatic level. Numerous political differences often result in economic losses both for Latvia and Russia. Despite the fact that Latvia has been an independent state for more than 20 years, there are still some unresolved issues in its relations with Russia. Today, relations between the two countries are often viewed through the prism of EU — Russia relations. Nonetheless, they often do not fit this context. Settling differences between Latvia and Russia will contribute to trade relations, which are increasingly important for both parties. In order to prevent and localise emerging conflicts, diplomats, politicians, and experts should interpret Russian-Latvian relations in view of the national features without referring to theoretical models based on the mythological “unity” of the three Baltic States.

  11. Existence of solutions for quasistatic problems of unilateral contact with nonlocal friction for nonlinear elastic materials

    Alain Mignot

    2005-09-01

    Full Text Available This paper shows the existence of a solution of the quasi-static unilateral contact problem with nonlocal friction law for nonlinear elastic materials. We set up a variational incremental problem which admits a solution, when the friction coefficient is small enough, and then by passing to the limit with respect to time we obtain a solution.

  12. A fast nonlinear conjugate gradient based method for 3D frictional contact problems

    Zhao, J.; Vollebregt, E.A.H.; Oosterlee, C.W.

    2014-01-01

    This paper presents a fast numerical solver for a nonlinear constrained optimization problem, arising from a 3D frictional contact problem. It incorporates an active set strategy with a nonlinear conjugate gradient method. One novelty is to consider the tractions of each slip element in a polar

  13. A fast nonlinear conjugate gradient based method for 3D concentrated frictional contact problems

    J. Zhao (Jing); E.A.H. Vollebregt (Edwin); C.W. Oosterlee (Cornelis)

    2015-01-01

    htmlabstractThis paper presents a fast numerical solver for a nonlinear constrained optimization problem, arising from 3D concentrated frictional shift and rolling contact problems with dry Coulomb friction. The solver combines an active set strategy with a nonlinear conjugate gradient method. One

  14. A Class of time-fractional hemivariational inequalities with application to frictional contact problem

    Zeng, Shengda; Migórski, Stanisław

    2018-03-01

    In this paper a class of elliptic hemivariational inequalities involving the time-fractional order integral operator is investigated. Exploiting the Rothe method and using the surjectivity of multivalued pseudomonotone operators, a result on existence of solution to the problem is established. Then, this abstract result is applied to provide a theorem on the weak solvability of a fractional viscoelastic contact problem. The process is quasistatic and the constitutive relation is modeled with the fractional Kelvin-Voigt law. The friction and contact conditions are described by the Clarke generalized gradient of nonconvex and nonsmooth functionals. The variational formulation of this problem leads to a fractional hemivariational inequality.

  15. Probing wavenumbers of current-induced excitations in point-contact experiments

    Z Wei

    2010-06-01

    Full Text Available Z Wei, M TsoiDepartment of Physics, Center for Nano and Molecular Science and Technology, and Texas Materials Institute, The University of Texas at Austin, Austin, TX, USAAbstract: We demonstrate how a mechanical point-contact technique can provide information on the wavenumber of spin waves excited by high-density electrical current in magnetic multilayers. By varying the size of point-contacts, we have been able to control the size of the excitation volume and therefore the wavelength of current-induced spin waves. This leads to a technique with in situ sensitivity to wavenumbers of current-induced excitations. Our detailed size-dependent measurements support the prediction that the excited wavelength is determined by the contact size.Keywords: spin transfer torque, giant magnetoresistance, spin waves, point contact

  16. Application of an enriched FEM technique in thermo-mechanical contact problems

    Khoei, A. R.; Bahmani, B.

    2018-02-01

    In this paper, an enriched FEM technique is employed for thermo-mechanical contact problem based on the extended finite element method. A fully coupled thermo-mechanical contact formulation is presented in the framework of X-FEM technique that takes into account the deformable continuum mechanics and the transient heat transfer analysis. The Coulomb frictional law is applied for the mechanical contact problem and a pressure dependent thermal contact model is employed through an explicit formulation in the weak form of X-FEM method. The equilibrium equations are discretized by the Newmark time splitting method and the final set of non-linear equations are solved based on the Newton-Raphson method using a staggered algorithm. Finally, in order to illustrate the capability of the proposed computational model several numerical examples are solved and the results are compared with those reported in literature.

  17. Semi-Smooth Newton Method for Solving 2D Contact Problems with Tresca and Coulomb Friction

    Kristina Motyckova

    2013-01-01

    Full Text Available The contribution deals with contact problems for two elastic bodies with friction. After the description of the problem we present its discretization based on linear or bilinear finite elements. The semi--smooth Newton method is used to find the solution, from which we derive active sets algorithms. Finally, we arrive at the globally convergent dual implementation of the algorithms in terms of the Langrange multipliers for the Tresca problem. Numerical experiments conclude the paper.

  18. On a solvability of hydro-mechanical problem based on contact problem with visco-plastic friction in Bingham rheology

    Nedoma, Jiří; Tomášek, Luboš

    2008-01-01

    Roč. 218, č. 1 (2008), s. 116-124 ISSN 0377-0427 Institutional research plan: CEZ:AV0Z10300504 Keywords : visco-plasticity * Bingham rheology * contact problems with friction * variational inequalities * FEM * geomechanics * hydromechanics Subject RIV: BA - General Mathematics Impact factor: 1.048, year: 2008

  19. Dynamic contact problem with adhesion and damage between thermo-electro-elasto-viscoplastic bodies

    Hadj ammar, Tedjani; Saïdi, Abdelkader; Azeb Ahmed, Abdelaziz

    2017-05-01

    We study of a dynamic contact problem between two thermo-electro-elasto-viscoplastic bodies with damage and adhesion. The contact is frictionless and is modeled with normal compliance condition. We derive variational formulation for the model and prove an existence and uniqueness result of the weak solution. The proof is based on arguments of evolutionary variational inequalities, parabolic inequalities, differential equations, and fixed point theorem.

  20. Frictional contact problems for electro-viscoelastic materials with long-term memory, damage, and adhesion

    Tedjani Hadj Ammar

    2014-10-01

    Full Text Available We consider a quasistatic contact problem between two electro-viscoelastic bodies with long-term memory and damage. The contact is frictional and is modelled with a version of normal compliance condition and the associated Coulomb's law of friction in which the adhesion of contact surfaces is taken into account. We derive a variational formulation for the model and prove an existence and uniqueness result of the weak solution. The proof is based on arguments of evolutionary variational inequalities, a classical existence and uniqueness result on parabolic inequalities, and Banach fixed point theorem.

  1. Short-circuit current improvement in thin cells with a gridded back contact

    Giuliano, M.; Wohlgemuth, J.

    1980-01-01

    The use of gridded back contact on thin silicon solar cells 50 micrometers was investigated. An unexpected increase in short circuit current of almost 10 percent was experienced for 2 cm x 2 cm cells. Control cells with the standard continuous contact metallization were fabricated at the same time as the gridded back cells with all processes identical up to the formation of the back contact. The gridded back contact pattern was delineated by evaporation of Ti-Pd over a photo-resist mask applied to the back of the wafer; the Ti-Pd film on the controls was applied in the standard fashion in a continuous layer over the back of the cell. The Ti-Pd contacts were similarly applied to the front of the wafer, and the grid pattern on both sides of the cell was electroplated with 8-10 micrometers of silver.

  2. History-Dependent Problems with Applications to Contact Models for Elastic Beams

    Bartosz, Krzysztof; Kalita, Piotr; Migórski, Stanisław; Ochal, Anna; Sofonea, Mircea

    2016-01-01

    We prove an existence and uniqueness result for a class of subdifferential inclusions which involve a history-dependent operator. Then we specialize this result in the study of a class of history-dependent hemivariational inequalities. Problems of such kind arise in a large number of mathematical models which describe quasistatic processes of contact. To provide an example we consider an elastic beam in contact with a reactive obstacle. The contact is modeled with a new and nonstandard condition which involves both the subdifferential of a nonconvex and nonsmooth function and a Volterra-type integral term. We derive a variational formulation of the problem which is in the form of a history-dependent hemivariational inequality for the displacement field. Then, we use our abstract result to prove its unique weak solvability. Finally, we consider a numerical approximation of the model, solve effectively the approximate problems and provide numerical simulations

  3. History-Dependent Problems with Applications to Contact Models for Elastic Beams

    Bartosz, Krzysztof; Kalita, Piotr; Migórski, Stanisław; Ochal, Anna, E-mail: ochal@ii.uj.edu.pl [Jagiellonian University, Faculty of Mathematics and Computer Science (Poland); Sofonea, Mircea [Université de Perpignan Via Domitia, Laboratoire de Mathématiques et Physique (France)

    2016-02-15

    We prove an existence and uniqueness result for a class of subdifferential inclusions which involve a history-dependent operator. Then we specialize this result in the study of a class of history-dependent hemivariational inequalities. Problems of such kind arise in a large number of mathematical models which describe quasistatic processes of contact. To provide an example we consider an elastic beam in contact with a reactive obstacle. The contact is modeled with a new and nonstandard condition which involves both the subdifferential of a nonconvex and nonsmooth function and a Volterra-type integral term. We derive a variational formulation of the problem which is in the form of a history-dependent hemivariational inequality for the displacement field. Then, we use our abstract result to prove its unique weak solvability. Finally, we consider a numerical approximation of the model, solve effectively the approximate problems and provide numerical simulations.

  4. A frictional contact problem with wear involving elastic-viscoplastic materials with damage and thermal effects

    Abdelmoumene Djabi

    2015-05-01

    Full Text Available We consider a mathematical problem for quasistatic contact between a thermo-elastic-viscoplastic body with damage and an obstacle. The contact is frictional and bilateral with a moving rigid foundation which results in the wear of the contacting surface. We employ the thermo-elasticviscoplastic with damage constitutive law for the material. The damage of the material caused by elastic deformations. The evolution of the damage is described by an inclusion of parabolic type. The problem is formulated as a coupled system of an elliptic variational inequality for the displacement, a parabolic variational inequality for the damage and the heat equation for the temperature. We establish a variational formulation for the model and we prove the existence of a unique weak solution to the problem. The proof is based on a classical existence and uniqueness result on parabolic inequalities, differential equations and fixed point arguments.

  5. Unexpected current lowering of Mg contact on SI-GaAs

    Dubecky, F.; Bohacek, F.; Sekacova, M.; Hubik, P.; Kindl, D.; Gombia, E.; Necas, V.

    2016-01-01

    Four SI-GaAs surface barrier diodes with different contact metallization and/or contact areas were prepared and characterized in terms of the I-V measurements. The possibility of tuning their performance has been demonstrated by virtue of the device engineering, involving a low work-function Mg metallization and manipulation of the contact area. A device with a remarkable current lowering, by almost two orders of magnitude with respect to the 'standard' sample, was prepared. Such a possibility opens new application choices for SI-GaAs not recognized before. We suggest its use, with appropriate metal contact/s, in devices with a low current at low-voltage requirements, such as photonic devices, photodiodes or different physical sensors. The reported data and evidence from the existing literature rule out the widely accepted mechanism of ohmic/bulk-limited and thermionic emission transport as general rules for the interpretation of the low-bias regime in SI-GaAs diodes. The strong blocking ability of the low work function Mg contact was attributed to the downwards band bending, near contact charge carriers accumulation and the corresponding lowering of the bulk SI-GaAs free carrier concentration. (authors)

  6. Rapid growth, maturity, current problems, future prospects of NAA

    Guinn, V.P.

    2000-01-01

    The early rapid growth, the attainment of maturity, current problems, and future prospects of NAA (neutron activation analysis) are discussed, each in reasonable detail. In particular, the nature and causes of its current problems are examined, and suggestions are presented for the solution of these problems. The author believes that vigorous action in suggested areas of concentration can reinvigorate the status of NAA as an important method of elemental analysis. (author)

  7. Criminal Justice Contact, Stressors, and Obesity-Related Health Problems Among Black Adults in the USA.

    Archibald, Paul C; Parker, Lauren; Thorpe, Roland

    2018-04-01

    Criminal justice contact-defined as lifetime arrest, parole, or incarceration, seems to exacerbate chronic conditions, and those who are most likely to have had contact with the criminal justice system, such as Black adults, often already have pre-existing disproportionately high rates of stress and chronic conditions due to the social determinants of health that affect underrepresented minorities. Findings from this study suggest that there is a mechanism that links the stressors among Black adults manifested by such factors as family, financial, neighborhood, and personal problems with criminal justice contact to obesity-related health status. Using the National Survey of American Life (NSAL), modified Poisson regression analyses were used to determine the association between criminal justice contact, stressors, and obesity-related health problems among a national sample of Black adults (n = 5008). In the full model, the odds of experiencing obesity-related health problems for Black adults who had criminal justice contact was reduced (PR, 1.23 to 1.14) and not statistically significant. Black adults who reported experiencing family stressors (PR, 1.21; 95% CI, 1.08, 1.36), financial stressors (PR, 1.30; 95% CI, 1.16, 1.47), and personal stressors (PR, 1.16; 95% CI, 1.02, 1.31) were statistically significant and higher than those who reported not experiencing any of these stressors; neighborhood stressors was not statistically significant. The evidence suggests a relationship between the stressors associated with criminal justice contact and obesity-related health status. These findings emphasize the need to further explore the family, financial, and personal stressors for Black adults with criminal justice contact in order to further our understanding of their obesity-related health problems.ᅟ.

  8. Efficient numerical methods for the large-scale, parallel solution of elastoplastic contact problems

    Frohne, Jörg

    2015-08-06

    © 2016 John Wiley & Sons, Ltd. Quasi-static elastoplastic contact problems are ubiquitous in many industrial processes and other contexts, and their numerical simulation is consequently of great interest in accurately describing and optimizing production processes. The key component in these simulations is the solution of a single load step of a time iteration. From a mathematical perspective, the problems to be solved in each time step are characterized by the difficulties of variational inequalities for both the plastic behavior and the contact problem. Computationally, they also often lead to very large problems. In this paper, we present and evaluate a complete set of methods that are (1) designed to work well together and (2) allow for the efficient solution of such problems. In particular, we use adaptive finite element meshes with linear and quadratic elements, a Newton linearization of the plasticity, active set methods for the contact problem, and multigrid-preconditioned linear solvers. Through a sequence of numerical experiments, we show the performance of these methods. This includes highly accurate solutions of a three-dimensional benchmark problem and scaling our methods in parallel to 1024 cores and more than a billion unknowns.

  9. Efficient numerical methods for the large-scale, parallel solution of elastoplastic contact problems

    Frohne, Jö rg; Heister, Timo; Bangerth, Wolfgang

    2015-01-01

    © 2016 John Wiley & Sons, Ltd. Quasi-static elastoplastic contact problems are ubiquitous in many industrial processes and other contexts, and their numerical simulation is consequently of great interest in accurately describing and optimizing production processes. The key component in these simulations is the solution of a single load step of a time iteration. From a mathematical perspective, the problems to be solved in each time step are characterized by the difficulties of variational inequalities for both the plastic behavior and the contact problem. Computationally, they also often lead to very large problems. In this paper, we present and evaluate a complete set of methods that are (1) designed to work well together and (2) allow for the efficient solution of such problems. In particular, we use adaptive finite element meshes with linear and quadratic elements, a Newton linearization of the plasticity, active set methods for the contact problem, and multigrid-preconditioned linear solvers. Through a sequence of numerical experiments, we show the performance of these methods. This includes highly accurate solutions of a three-dimensional benchmark problem and scaling our methods in parallel to 1024 cores and more than a billion unknowns.

  10. Non-steady state modelling of wheel-rail contact problem

    Guiral, A.; Alonso, A.; Baeza, L.; Giménez, J. G.

    2013-01-01

    Among all the algorithms to solve the wheel-rail contact problem, Kalker's FastSim has become the most useful computation tool since it combines a low computational cost and enough precision for most of the typical railway dynamics problems. However, some types of dynamic problems require the use of a non-steady state analysis. Alonso and Giménez developed a non-stationary method based on FastSim, which provides both, sufficiently accurate results and a low computational cost. However, it presents some limitations; the method is developed for one time-dependent creepage and its accuracy for varying normal forces has not been checked. This article presents the required changes in order to deal with both problems and compares its results with those given by Kalker's Variational Method for rolling contact.

  11. Electric field effect on the critical current of SNS-contact

    Rakhmanov, A.L.; Rozhkov, A.V.

    1995-01-01

    Electric field effect on the SNS-contact critical current is investigated in the Ginzburg-Landau theory approximation. It is shown that the electric field may cause a notable increase of the contact critical current especially if the sample temperature is close to the temperature of a superconducting transition of T sc normal layer. Electric field effect is increased with the reduction of film thickness, but it can strong enough for thick films as well at temperature close to T sc . 11 refs.; 4 figs

  12. Primal and Dual Penalty Methods for Contact Problems with Geometrical Non-linearities

    Vondrák, V.; Dostál, Z.; Dobiáš, Jiří; Pták, Svatopluk

    -, č. 5 (2005), s. 449-450 ISSN 1617-7061. [GAMM Annual Meeting 2005. Luxembourg, 28.03.2005-01.04.2005] R&D Projects: GA ČR(CZ) GA101/05/0423 Institutional research plan: CEZ:AV0Z20760514 Keywords : primal penalty * dual penalty * contact problem Subject RIV: BA - General Mathematics

  13. Solvability of Static Contact Problems with Coulomb Friction for Orthotropic Material

    Eck, C.; Jarušek, Jiří

    2008-01-01

    Roč. 93, č. 1 (2008), s. 93-104 ISSN 0374-3535 R&D Projects: GA AV ČR IAA1075402 Institutional research plan: CEZ:AV0Z10190503 Keywords : contact problem * Coulomb friction * orthotropic elasticity Subject RIV: BA - General Mathematics Impact factor: 1.277, year: 2008

  14. Contact Problem of Disk on Shaft Fixed by Induction Shrink Fit

    Ulrych, B.; Kotlan, V.; Doležel, Ivo

    2012-01-01

    Roč. 88, 12B (2012), s. 32-34 ISSN 0033-2097 Institutional research plan: CEZ:AV0Z20760514 Keywords : induction shrink fit * contact problem * transfer of torque Subject RIV: BA - General Mathematics Impact factor: 0.244, year: 2011

  15. On the the Contact Lens Problem: Modeling Rigid and Elastic Beams on Thin Films

    Trinh, Philippe; Wilson, Stephen; Stone, Howard

    2011-11-01

    Generally, contact lenses are prescribed by the practitioner to fit each individual patient's eye, but these fitting-philosophies are based on empirical studies and a certain degree of trial-and-error. A badly fitted lens can cause a range of afflictions, which varies from mild dry-eye-discomfort, to more serious corneal diseases. Thus, at this heart of this problem, is the question of how a rigid or elastic plate interacts with the free-surface of a thin viscous film. In this talk, we present several mathematical models for the study of these plate-and-fluid problems. Asymptotic and numerical results are described, and we explain the role of elasticity, surface tension, viscosity, and pressure in determining the equilibrium solutions. Finally, we discuss the implications of our work on the contact lens problem, as well as on other coating processes which involve elastic substrates.

  16. E-waste: Environmental Problems and Current Management

    D. Aktsoglou

    2010-01-01

    Full Text Available In this paper the environmental problems related with the discarded electronic appliances, known as e-waste, are reviewed.Moreover, the current and the future production of e-waste, the potential environmental problems associated with theirdisposal and management practices are discussed whereas the existing e-waste management schemes in Greece and othercountries (Japan, Switzerland are also quoted.

  17. Effect of the Debye screening on the tunnel current through simple electrochemical bridged contact

    Kuznetsov, A.M.; Medvedev, Oleg; Ulstrup, Jens

    2008-01-01

    General equations for tunnel current through electrochemical contact containing a redox-center in molecular bridge group are observed with allowing for potential distribution in the tunnel gap. Simple approximate expressions appropriate for the analysis of experimental data are also derived. The ...

  18. Unexpected current lowering by a low work-funkction metal contact: Mg/SI-GaAs

    Dubecký, F.; Dubecký, M.; Hubík, Pavel; Kindl, Dobroslav; Gombia, E.; Baldini, M.; Nečas, V.

    2013-01-01

    Roč. 82, APR (2013), s. 72-76 ISSN 0038-1101 Institutional support: RVO:68378271 Keywords : Schottky barrier * low-bias transport * semi-insulating GaAs * low work -function * high resistence * low leakage current * blocking contact Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.514, year: 2013

  19. Non-steady state modeling of wheel-rail contact problem

    Guiral, A.; Alonso, A.; Baeza González, Luis Miguel; Giménez, J.G.

    2013-01-01

    Among all the algorithms to solve the wheel–rail contact problem, Kalker's FastSim has become the most useful computation tool since it combines a low computational cost and enough precision for most of the typical railway dynamics problems. However, some types of dynamic problems require the use of a non-steady state analysis. Alonso and Giménez developed a non-stationary method based on FastSim, which provides both, sufficiently accurate results and a low computational cost. However, it pre...

  20. A dynamic unilateral contact problem with adhesion and friction in viscoelasticity

    Cocou, Marius; Schryve, Mathieu; Raous, Michel

    2010-08-01

    The aim of this paper is to study an interaction law coupling recoverable adhesion, friction and unilateral contact between two viscoelastic bodies of Kelvin-Voigt type. A dynamic contact problem with adhesion and nonlocal friction is considered and its variational formulation is written as the coupling between an implicit variational inequality and a parabolic variational inequality describing the evolution of the intensity of adhesion. The existence and approximation of variational solutions are analysed, based on a penalty method, some abstract results and compactness properties. Finally, some numerical examples are presented.

  1. Workshops and problems for benchmarking eddy current codes

    Turner, L.R.; Davey, K.; Ida, N.; Rodger, D.; Kameari, A.; Bossavit, A.; Emson, C.R.I.

    1988-02-01

    A series of six workshops was held to compare eddy current codes, using six benchmark problems. The problems include transient and steady-state ac magnetic fields, close and far boundary conditions, magnetic and non-magnetic materials. All the problems are based either on experiments or on geometries that can be solved analytically. The workshops and solutions to the problems are described. Results show that many different methods and formulations give satisfactory solutions, and that in many cases reduced dimensionality or coarse discretization can give acceptable results while reducing the computer time required. 13 refs., 1 tab

  2. Eddy current inspection on heat exchanger tubes - problems and limitations

    Ilham Mukriz; Zainal Abidin Mohamed; Hairul Hasmoni Khairul Anuar; Mohd Salleh; Mahmood Dollah

    2005-01-01

    This paper focus on problems associated to eddy current inspection of heat exchanger tubes. A brief review on heat exchanger design and operation is presented. Eddy current technique in identifying inhomogeneity in tested tubes is discussed, highlighting its limitation in distinguishing between real pit type defects and other mundane anomalies. The limitation of the eddy current probe and equipment pertinent to the inspection are identified and areas of improvement are discussed. (Author)

  3. A model-adaptivity method for the solution of Lennard-Jones based adhesive contact problems

    Ben Dhia, Hachmi; Du, Shuimiao

    2018-05-01

    The surface micro-interaction model of Lennard-Jones (LJ) is used for adhesive contact problems (ACP). To address theoretical and numerical pitfalls of this model, a sequence of partitions of contact models is adaptively constructed to both extend and approximate the LJ model. It is formed by a combination of the LJ model with a sequence of shifted-Signorini (or, alternatively, -Linearized-LJ) models, indexed by a shift parameter field. For each model of this sequence, a weak formulation of the associated local ACP is developed. To track critical localized adhesive areas, a two-step strategy is developed: firstly, a macroscopic frictionless (as first approach) linear-elastic contact problem is solved once to detect contact separation zones. Secondly, at each shift-adaptive iteration, a micro-macro ACP is re-formulated and solved within the multiscale Arlequin framework, with significant reduction of computational costs. Comparison of our results with available analytical and numerical solutions shows the effectiveness of our global strategy.

  4. Kalker's algorithm Fastsim solves tangential contact problems with slip-dependent friction and friction anisotropy

    Piotrowski, J.

    2010-07-01

    This paper presents two extensions of Kalker's algorithm Fastsim of the simplified theory of rolling contact. The first extension is for solving tangential contact problems with the coefficient of friction depending on slip velocity. Two friction laws have been considered: with and without recuperation of the static friction. According to the tribological hypothesis for metallic bodies shear failure, the friction law without recuperation of static friction is more suitable for wheel and rail than the other one. Sample results present local quantities inside the contact area (division to slip and adhesion, traction) as well as global ones (creep forces as functions of creepages and rolling velocity). For the coefficient of friction diminishing with slip, the creep forces decay after reaching the maximum and they depend on the rolling velocity. The second extension is for solving tangential contact problems with friction anisotropy characterised by a convex set of the permissible tangential tractions. The effect of the anisotropy has been shown on examples of rolling without spin and in the presence of pure spin for the elliptical set. The friction anisotropy influences tangential tractions and creep forces. Sample results present local and global quantities. Both extensions have been described with the same language of formulation and they may be merged into one, joint algorithm.

  5. Current Quality-of-Life Tools Available for Use in Contact Dermatitis.

    Swietlik, Jacquelyn; Reeder, Margo

    2016-01-01

    Contact dermatitis is a common dermatologic condition that can cause significant impairment in patients' overall quality of life (QoL). This impact is separate and potentially more clinically relevant than one's disease "severity" in contact dermatitis and should be consistently addressed by dermatologists. Despite this, QoL tools specific to contact dermatitis are lacking, and there is little consistency in the literature regarding the tool used to evaluate clinical response to therapies. Measurements currently available to evaluate disease-related QoL in contact dermatitis fit into 1 of the following 3 general types: generic health-related QoL measures, dermatology-related QoL measures, or specific dermatologic disease-related QoL measures. This article reviews the strengths and weaknesses of existing QoL tools used in contact dermatitis including: Short Form Survey 36, Dermatology Life Quality Index, Skindex-29, Skindex-16, Dermatology-Specific Quality of Life, and Fragrance Quality of Life Index.

  6. A parametric study of contact problem on a large size flange

    Mukherjee, A.B.; Narayanan, T.; Dhondkar, J.K.; Mehra, V.K.

    1989-01-01

    Continuous change of contact point on gasket face with the application of bolt load makes it a non-linear problem. Thus the geometric non-linearity of the structure is simulated and a stress distribution over the gasket face is presented in this paper. The paper also describes the use of taper on the gasket face to reduce the stress peaking and to optimize the gasket face separation

  7. Existence of solutions for the dynamic frictional contact problem of isotropic viscoelastic bodies

    Eck, C.; Jarušek, Jiří

    2003-01-01

    Roč. 53, č. 2 (2003), s. 157-181 ISSN 0362-546X R&D Projects: GA AV ČR IAA1075005; GA AV ČR IAA1075707 Institutional research plan: CEZ:AV0Z1019905; CEZ:AV0Z1019905 Keywords : dynamic contact problem * parabolic equation * Coulomb law of friction Subject RIV: BA - General Mathematics Impact factor: 0.354, year: 2003

  8. Shape Optimization in Three-Dimensional Contact Problems with Coulomb Friction

    Beremlijski, P.; Haslinger, J.; Kočvara, Michal; Kučera, R.; Outrata, Jiří

    2009-01-01

    Roč. 20, č. 1 (2009), s. 416-444 ISSN 1052-6234 R&D Projects: GA AV ČR IAA100750802; GA AV ČR IAA1075402 Grant - others:European Commision(XE) FP6 - 30717; GA ČR(CZ) GA201/07/0294 Institutional research plan: CEZ:AV0Z10750506 Keywords : shape optimization * contact problems * Coulomb friction Subject RIV: BA - General Mathematics Impact factor: 1.429, year: 2009

  9. Soldered Contact and Current Risetime Effects on Negative Polarity Wire Array Z-pinches

    Chalenski, D. A.; Kusse, B. R.; Greenly, J. B.; Blesener, I. C.; McBride, R. D.; Hammer, D. A.; Knapp, P. F.

    2009-01-01

    The Cornell University COBRA pulser is a nominal 1 MA machine, capable of driving up to 32 wire cylindrical Z-pinch arrays. COBRA can operate with variable current risetimes ranging from 100 ns to 200 ns (short and long pulse, respectively). Wires are typically strung with a ''press'' contact to the electrode hardware, where the wire is loosely pulled against the hardware and held there to establish electrical contact. The machine is normally negative, but a bolt-on convolute can be used to modify the current path and effectively produce positive polarity operation at the load.Previous research with single wires on a 1-5 kA pulser has shown that soldering the wire, thereby improving the wire/electrode contact, and operating in positive polarity can improve the energy deposition into the wire and enhance wire core expansion. Negative polarity showed no difference. Previous experiments on the negative polarity, 20 MA, 100 ns Z accelerator have shown that improving the contact improved the x-ray yield.Cornell data were collected on 16-wire Aluminum Z-pinch arrays in negative polarity. Experiments were conducted with both short and long current pulses with soldered and no-soldered wire/electrode contacts. The initiation, ablation, implosion and stagnation phases were compared for these four conditions. Time dependent x-ray signals were measured using diodes and diamond detectors. An inductive voltage monitor was used to infer minimum current radius achieved, as defined by a uniform shell of current moving radially inward, producing a time dependent inductance. Total energy data were collected with a metal-strip bolometer. Self-emission data were collected by an XUV 4-frame camera and an optical streak camera.In negative polarity and with short pulses, soldering appeared to produce a smaller radius pinch and decrease variations in the x-ray pulse shape. The bolometer, laser backlighter, 4-frame and streak cameras showed negligible differences in the initiation ablation

  10. Computational dosimetry for grounded and ungrounded human models due to contact current

    Chan, Kwok Hung; Hattori, Junya; Laakso, Ilkka; Hirata, Akimasa; Taki, Masao

    2013-01-01

    This study presents the computational dosimetry of contact currents for grounded and ungrounded human models. The uncertainty of the quasi-static (QS) approximation of the in situ electric field induced in a grounded/ungrounded human body due to the contact current is first estimated. Different scenarios of cylindrical and anatomical human body models are considered, and the results are compared with the full-wave analysis. In the QS analysis, the induced field in the grounded cylindrical model is calculated by the QS finite-difference time-domain (QS-FDTD) method, and compared with the analytical solution. Because no analytical solution is available for the grounded/ungrounded anatomical human body model, the results of the QS-FDTD method are then compared with those of the conventional FDTD method. The upper frequency limit for the QS approximation in the contact current dosimetry is found to be 3 MHz, with a relative local error of less than 10%. The error increases above this frequency, which can be attributed to the neglect of the displacement current. The QS or conventional FDTD method is used for the dosimetry of induced electric field and/or specific absorption rate (SAR) for a contact current injected into the index finger of a human body model in the frequency range from 10 Hz to 100 MHz. The in situ electric fields or SAR are compared with the basic restrictions in the international guidelines/standards. The maximum electric field or the 99th percentile value of the electric fields appear not only in the fat and muscle tissues of the finger, but also around the wrist, forearm, and the upper arm. Some discrepancies are observed between the basic restrictions for the electric field and SAR and the reference levels for the contact current, especially in the extremities. These discrepancies are shown by an equation that relates the current density, tissue conductivity, and induced electric field in the finger with a cross-sectional area of 1 cm 2 . (paper)

  11. THE DYNAMIC INTERACTION OF THE MOVING CONTACTING SURFACES AT THE EXAMPLE OF THE ELECTRIC ROLLING STOCK CURRENT COLLECTOR

    M. O. Babiak

    2009-07-01

    Full Text Available The process of mutual moving and contacting of surfaces of current collecting pantograph elements and contact network is considered taking into account the particularities of inf1uence of speed and acceleration parameters, determination of which will allow to forecast mathematically the wear-out degree of contacting elements.

  12. Current problems of the nuclear power - society relationship in Romania

    Constantin, Marin

    2004-01-01

    The present work tries to make an analysis of the current aspects of the interaction between the nuclear field, environment and society. One starts from the general conception of sustainable development. The analysis focusses mainly the social side of the sustainable development and the environmental protection issues. As prominent appears the sensitive problem of radioactive waste management. The papers analyses the current public perception, the mutations expected in the public opinion as well as the problems which the nuclear industry and decision makers confront to harmonize the requirements in the nuclear power sector and those imposed by society. Particularly focused is the situation in Romania

  13. Workshops and problems for benchmarking eddy current codes

    Turner, L.R.; Davey, K.; Ida, N.; Rodger, D.; Kameari, A.; Bossavit, A.; Emson, C.R.I.

    1988-08-01

    A series of six workshops was held in 1986 and 1987 to compare eddy current codes, using six benchmark problems. The problems included transient and steady-state ac magnetic fields, close and far boundary conditions, magnetic and non-magnetic materials. All the problems were based either on experiments or on geometries that can be solved analytically. The workshops and solutions to the problems are described. Results show that many different methods and formulations give satisfactory solutions, and that in many cases reduced dimensionality or coarse discretization can give acceptable results while reducing the computer time required. A second two-year series of TEAM (Testing Electromagnetic Analysis Methods) workshops, using six more problems, is underway. 12 refs., 15 figs., 4 tabs.

  14. Workshops and problems for benchmarking eddy current codes

    Turner, L.R.; Davey, K.; Ida, N.; Rodger, D.; Kameari, A.; Bossavit, A.; Emson, C.R.I.

    1988-08-01

    A series of six workshops was held in 1986 and 1987 to compare eddy current codes, using six benchmark problems. The problems included transient and steady-state ac magnetic fields, close and far boundary conditions, magnetic and non-magnetic materials. All the problems were based either on experiments or on geometries that can be solved analytically. The workshops and solutions to the problems are described. Results show that many different methods and formulations give satisfactory solutions, and that in many cases reduced dimensionality or coarse discretization can give acceptable results while reducing the computer time required. A second two-year series of TEAM (Testing Electromagnetic Analysis Methods) workshops, using six more problems, is underway. 12 refs., 15 figs., 4 tabs

  15. Analytical model development of an eddy-current-based non-contacting steel plate conveyance system

    Liu, C.-T.; Lin, S.-Y.; Yang, Y.-Y.; Hwang, C.-C.

    2008-01-01

    A concise model for analyzing and predicting the quasi-static electromagnetic characteristics of an eddy-current-based non-contacting steel plate conveyance system has been developed. Confirmed by three-dimensional (3-D) finite element analysis (FEA), adequacy of the analytical model can be demonstrated. Such an effective approach, which can be conveniently used by the potential industries for preliminary system operational performance evaluations, will be essential for designers and on-site engineers

  16. Publication analysis of the contact lens field: what are the current topics of interest?

    Cardona, Genís; Sanz, Joan P

    2015-01-01

    To determine the main current research interests of scientists working in the contact lens field. All articles published in the 2011 issues of all journals included in the Journal Citation Reports subject category Ophthalmology were inspected to expose those papers related to the contact lens field. Information regarding source journal was obtained and authorship details were recorded to determine the top most prolific authors, institutions and countries. A comprehensive list of key words was compiled to generate a two-dimensional term map in which the frequency of occurrence of a particular term is defined by label size and the distance between two terms is an indication of the relatedness of these terms, based on their co-occurrences within groups of key words. Clusters of related terms were also identified. Visual examination of all articles uncovered a total of 156 papers, published in 28 different journals. Contact Lens & Anterior Eye, Eye & Contact Lens and Optometry and Vision Science had 27 articles each. The most prolific authors and institutions revealed the predominance of countries with long research tradition in the contact lens field. Ten different word clusters or areas of interest were identified, including both traditional, yet unresolved issues (e.g., comfort or dry eye), and the latest research efforts (e.g., myopia control). These findings, which revealed contact lenses to be a fertile area of research, may be of relevance to new researchers as well as to those interested in exploring the latest research trends in this scientific discipline. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  17. AACSB Accreditation in China--Current Situation, Problems, and Solutions

    Zhang, Xinrui; Gao, Yan

    2012-01-01

    This paper first introduces the background of the AACSB (Association to Advance Collegiate Schools of Business) accreditation, and then analyzes the current status of the participation of Chinese business schools in AACSB accreditation. Based on the data analysis, the paper points out that there are two main problems in the Chinese business…

  18. Capacity Building for School Development: Current Problems and Future Challenges

    Ho, Dora; Lee, Moosung

    2016-01-01

    This article offers a theoretical discussion on the current problems and future challenges of school capacity building in early childhood education (ECE), aiming to highlight some key areas for future research. In recent years, there has been a notable policy shift from monitoring quality through inspection to improving quality through school…

  19. The Current Practices and Problems of School Based Supervision in ...

    The purpose of this study was to identify the current practice and problems of school based supervision in government primary schools of Jile Timuga Woreda of Oromia Zone. A descriptive survey design of research methodology was employed. Regarding sampling, there were 39 primary schools grouped in 10 cluster ...

  20. Shape Optimization in Contact Problems with Coulomb Friction and a Solution-Dependent Friction Coefficient

    Beremlijski, P.; Outrata, Jiří; Haslinger, Jaroslav; Pathó, R.

    2014-01-01

    Roč. 52, č. 5 (2014), s. 3371-3400 ISSN 0363-0129 R&D Projects: GA ČR(CZ) GAP201/12/0671 Grant - others:GA MŠK(CZ) CZ.1.05/1.1.00/02.0070; GA MŠK(CZ) CZ.1.07/2.3.00/20.0070 Institutional support: RVO:67985556 ; RVO:68145535 Keywords : shape optimization * contact problems * Coulomb friction * solution-dependent coefficient of friction * mathematical programs with equilibrium constraints Subject RIV: BA - General Mathematics Impact factor: 1.463, year: 2014 http://library.utia.cas.cz/separaty/2014/MTR/outrata-0434234.pdf

  1. A dynamic elastic-visco-plastic unilateral contact problem with normal damped response and Coulomb friction

    Eck, Ch.; Jarušek, Jiří; Sofonea, M.

    2010-01-01

    Roč. 21, č. 3 (2010), s. 229-251 ISSN 0956-7925 R&D Projects: GA AV ČR IAA100750802 Institutional research plan: CEZ:AV0Z10190503 Keywords : elastic-vosco plastic material * dynamic contact problem * normal damped response * unilateral constraint * Coulomb friction * weak solution * penalitazion * smoothing Subject RIV: BA - General Mathematics Impact factor: 1.480, year: 2010 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=7675484&fileId=S0956792510000045

  2. Carrier Transport of Silver Nanowire Contact to p-GaN and its Influence on Leakage Current of LEDs

    Oh, Munsik; Kang, Jae-Wook; Kim, Hyunsoo

    2018-03-01

    The authors investigated the silver nanowires (AgNWs) contact formed on p-GaN. Transmission line model applied to the AgNWs contact to p-GaN produced near ohmic contact with a specific contact resistance (ρ sc) of 10-1˜10-4 Ω·cm2. Noticeably, the contact resistance had a strong bias-voltage (or current-density) dependence associated with a local joule heating effect. Current-voltage-temperature (I-V-T) measurement revealed a strong temperature dependence with respect to ρ sc, indicating that the temperature played a key role of an enhanced carrier transport. The local joule heating at AgNW/GaN interface, however, resulted in a generation of leakage current of light-emitting diodes (LEDs) caused by degradation of AgNW contact.

  3. Modelling and solution of contact problem for infinite plate and cross-shaped embedment

    O.B. Kozin

    2016-09-01

    Full Text Available Development of efficient methods of determination of an intense-strained state of thin-walled constructional designs with inclusions, reinforcements and other stress raisers is an important problem both with theoretical, and from the practical point of view, considering their wide practical application. Aim: The aim of this research is to develop the analytical mathematical method of studying of an intense-strained state of infinite plate with cross-shaped embedment at a bend. Materials and Methods: The method of boundary elements is an efficient way of the boundary value problems solution for systems of differential equations. The methods based on boundary integral equations get wide application in many branches of science and technique, calculation of plates and shells. One of methods of solution of a numerous class of the integral equations and systems arising on the basis of a method of boundary integral equations is the analytical method of construction of these equations and systems to Riemann problems with their forthcoming decision. Results: The integral equation for the analysis of deflections and the analysis of an intense-strained state of a thin rigid plate with rigid cross-shaped embedment is received. The precise solution of this boundary value problem is received by reduction to a Riemann problem and its forthcoming solution. An asymptotical behavior of contact efforts at the ends of embedment is investigated.

  4. Contact resistance problems applying ERT on low bulk density forested stony soils. Is there a solution?

    Deraedt, Deborah; Touzé, Camille; Robert, Tanguy; Colinet, Gilles; Degré, Aurore; Garré, Sarah

    2015-04-01

    Electrical resistivity tomography (ERT) has often been put forward as a promising tool to quantify soil water and solute fluxes in a non-invasive way. In our experiment, we wanted to determine preferential flow processes along a forested hillslope using a saline tracer with ERT. The experiment was conducted in the Houille watershed, subcatchment of the Meuse located in the North of Belgian Ardennes (50° 1'52.6'N, 4° 53'22.5'E). The climate is continental but the soil under spruce (Picea abies (L.) Karst.) and Douglas fire stand (Pseudotsuga menziesii (Mirb.) Franco) remains quite dry (19% WVC in average) during the whole year. The soil is Cambisol and the parent rock is Devonian schist covered with variable thickness of silty loam soil. The soil density ranges from 1.13 to 1.87 g/cm3 on average. The stone content varies from 20 to 89% and the soil depth fluctuates between 70 and 130 cm. The ERT tests took place on June 1st 2012, April 1st, 2nd and 3rd 2014 and May 12th 2014. We used the Terrameter LS 12 channels (ABEM, Sweden) in 2012 test and the DAS-1 (Multi-Phase Technologies, United States) in 2014. Different electrode configurations and arrays were adopted for different dates (transect and grid arrays and Wenner - Schlumberger, Wenner alpha and dipole-dipole configurations). During all tests, we systematically faced technical problems, mainly related to bad electrode contact. The recorded data show values of contact resistance above 14873 Ω (our target value would be below 3000 Ω). Subsequently, we tried to improve the contact by predrilling the soil and pouring water in the electrode holes. The contact resistance improved to 14040 Ω as minimum. The same procedure with liquid mud was then tested to prevent quick percolation of the water from the electrode location. As a result, the lower contact resistance dropped to 11745 Ω. Finally, we applied about 25 litre of saline solution (CaCl2, 0.75g/L) homogeneously on the electrode grid. The minimum value of

  5. Test data on electrical contacts at high surface velocities and high current densities for homopolar generators

    Brennan, M.; Tolk, K.M.; Weldon, W.F.; Rylander, H.G.; Woodson, H.H.

    1977-01-01

    Test data is presented for one grade of copper graphite brush material, Morganite CMlS, over a wide range of surface velocities, atmospheres, and current densities that are expected for fast discharge (<100 ms) homopolar generators. The brushes were run on a copper coated 7075-T6 aluminum disk at surface speeds up to 277 m/sec. One electroplated copper and three flame sprayed copper coatings were used during the tests. Significant differences in contact voltage drops and surface mechanical properties of the copper coatings were observed

  6. The intermittent contact impact problem in piping systems of nuclear reactor

    Martin, A.; Ricard, A.; Millard, A.

    1981-09-01

    The intermittent contact problem is important in many pipe whip studies, specially as to the safety of nuclear reactors. The impact concept adopted is that of instantaneous impact, so that at the time of impact the two impacting structures instantaneously acquire the same velocity in the impact direction. Energy is dissipated by some mechanism whose spatial and temporal scale is small compared to these scales in the discrete model. This dissipation is associated with local plastic deformation. Different solutions are presented for solving this problem. The first one is a generalization of the modal superposition method, when the nonlinearities of the structure are only due to impact between structural components; the other ones are included in a step by step time history and can take in account geometrical non linearities and of behavior. Some industrial applications in nuclear technology are presented

  7. A nonlinear boundary integral equations method for the solving of quasistatic elastic contact problem with Coulomb friction

    Yurii M. Streliaiev

    2016-06-01

    Full Text Available Three-dimensional quasistatic contact problem of two linearly elastic bodies' interaction with Coulomb friction taken into account is considered. The boundary conditions of the problem have been simplified by the modification of the Coulomb's law of friction. This modification is based on the introducing of a delay in normal contact tractions that bound tangent contact tractions in the Coulomb's law of friction expressions. At this statement the problem is reduced to a sequence of similar systems of nonlinear integral equations describing bodies' interaction at each step of loading. A method for an approximate solution of the integral equations system corresponded to each step of loading is applied. This method consists of system regularization, discretization of regularized system and iterative process application for solving the discretized system. A numerical solution of a contact problem of an elastic sphere with an elastic half-space interaction under increasing and subsequently decreasing normal compressive force has been obtained.

  8. QCD analysis of neutral and charged current cross sections and search for contact interactions at HERA

    Pirumov, Hayk

    2013-11-15

    A QCD analysis of the inclusive deep inelastic ep scattering cross section measured by the H1 experiment at HERA is presented. The data correspond to a total integrated luminosity of about 0.5 fb{sup -1} and covers a kinematic range of 0.5 GeV{sup 2} - 30000 GeV{sup 2} in the negative four-momentum transfer Q{sup 2} and 3 . 10{sup -5} - 0.65 in Bjorken x. The performed QCD analysis of the double differential neutral and charged current cross sections results in a set of parton distribution functions H1PDF 2012. The precise data from HERA II period in the kinematic region of high Q{sup 2} considerably improve the accuracy of the PDFs at the high x. In addition a search for signs of new physics using single differential neutral current cross section measurements at high Q{sup 2} is performed. The observed good agreement of the analysed data with the Standard Model predictions allows to set constraints on various new physics models within the framework of contact interactions. Limits are derived on the compositeness scale for general contact interactions, on the ratio of mass to the Yukawa coupling for heavy leptoquark models, on the effective Plank-mass scale in the large extra dimension models and on the quark radius.

  9. True random bit generators based on current time series of contact glow discharge electrolysis

    Rojas, Andrea Espinel; Allagui, Anis; Elwakil, Ahmed S.; Alawadhi, Hussain

    2018-05-01

    Random bit generators (RBGs) in today's digital information and communication systems employ a high rate physical entropy sources such as electronic, photonic, or thermal time series signals. However, the proper functioning of such physical systems is bound by specific constrains that make them in some cases weak and susceptible to external attacks. In this study, we show that the electrical current time series of contact glow discharge electrolysis, which is a dc voltage-powered micro-plasma in liquids, can be used for generating random bit sequences in a wide range of high dc voltages. The current signal is quantized into a binary stream by first using a simple moving average function which makes the distribution centered around zero, and then applying logical operations which enables the binarized data to pass all tests in industry-standard randomness test suite by the National Institute of Standard Technology. Furthermore, the robustness of this RBG against power supply attacks has been examined and verified.

  10. A gradient stable scheme for a phase field model for the moving contact line problem

    Gao, Min

    2012-02-01

    In this paper, an efficient numerical scheme is designed for a phase field model for the moving contact line problem, which consists of a coupled system of the Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition [1,2,4]. The nonlinear version of the scheme is semi-implicit in time and is based on a convex splitting of the Cahn-Hilliard free energy (including the boundary energy) together with a projection method for the Navier-Stokes equations. We show, under certain conditions, the scheme has the total energy decaying property and is unconditionally stable. The linearized scheme is easy to implement and introduces only mild CFL time constraint. Numerical tests are carried out to verify the accuracy and stability of the scheme. The behavior of the solution near the contact line is examined. It is verified that, when the interface intersects with the boundary, the consistent splitting scheme [21,22] for the Navier Stokes equations has the better accuracy for pressure. © 2011 Elsevier Inc.

  11. Effect of the periphery of metal-semiconductor contacts with Schottky barriers on their static current-voltage characteristic

    Torkhov, N. A.

    2010-01-01

    Kelvin probe atomic-force microscopy of the electrostatic surface potential of gold Schottky contacts on n-GaAs showed that there is an extended transition area (halo) (tens of micrometers) around contacts in which the surface potential varies from the n-GaAs free surface potential to the gold contact surface potential. The contact potential and its distribution in the surrounding halo are controlled by the contact structure. The study of spreading currents showed that there is a high-conductance area (periphery) around the contact perimeter due to strong electric fields of the halo, which causes leakage currents. The conductivity of the main contact area is caused by 100- to 200-nm local areas with higher and lower conducting abilities. Mesa formation around contacts causes a decrease in the work function, a decrease in the halo extent and electric field strength, which is accompanied by spreading and decreasing of the peripheral area conductance. This results in disappearance of leakage currents and a decrease in the ideality index. In contrast, protection of the peripheral area by a SiO 2 insulating film 0.5 μm thick increases the work function, which is accompanied by the formation of potential lobes around the contact in two mutually perpendicular crystallographic directions. A stronger penetration of halo electric fields into the contact area results in an increase in the ideality index and disappearance of high-conductance peripheral area and leakage currents. The difference between the electrical properties of the periphery, gold grains, and their boundaries controls the contact switching mechanism when applying forward or reverse biases.

  12. FCL: A solution to fault current problems in DC networks

    Cointe, Y; Tixador, P; Villard, C

    2008-01-01

    Within the context of the electric power market liberalization, DC networks have many interests compared to AC ones. New energy landscapes open the way of a diversified production. Innovative interconnection diagrams, in particular using DC buses, are under development. In this case it is not possible to defer the fault current interruption in the AC side. DC fault current cutting remains a difficult problem. FCLs (Fault Current Limiters) enable to limit the current to a preset value, lower than the theoretical short-circuit current. For this application Coated Conductors (CC) offer an excellent opportunity. Due to these promising characteristics we build a test bench and work on the implementation of these materials. The test bench is composed by 10 power amplifiers, to reach 4 kVA in many configurations of current and voltage. We carried out limiting experiments on DyBaCuO CC from EHTS, samples are about five centimeters long and many potential measuring points are pasted on the shunt to estimate the quench homogeneity. Thermal phenomena in FCLs are essential, numerical models are important to calculate the maximum temperatures. To validate these models we measure the CC temperature by depositing thermal sensors (Cu resistance) above the shunt layer and the substrate. An electrical insulation with a low thermal resistivity between the CC and the sensors is necessary. We use a thin layer of Parylene because of its good mechanical and electrical insulation properties at low temperature. The better quench behaviour of CC for temperatures close to the critical temperature has been confirmed. The measurements are in good agreement with simulations, this validates the thermal models

  13. Inverse problems in eddy current testing using neural network

    Yusa, N.; Cheng, W.; Miya, K.

    2000-05-01

    Reconstruction of crack in conductive material is one of the most important issues in the field of eddy current testing. Although many attempts to reconstruct cracks have been made, most of them deal with only artificial cracks machined with electro-discharge. However, in the case of natural cracks like stress corrosion cracking or inter-granular attack, there must be contact region and therefore their conductivity is not necessarily zero. In this study, an attempt to reconstruct natural cracks using neural network is presented. The neural network was trained through numerical simulated data obtained by the fast forward solver that calculated unflawed potential data a priori to save computational time. The solver is based on A-φ method discretized by using FEM-BEM A natural crack was modeled as an area whose conductivity was less than that of a specimen. The distribution of conductivity in that area was reconstructed as well. It took much time to train the network, but the speed of reconstruction was extremely fast after once it was trained. Well-trained network gave good reconstruction result.

  14. PHYLLOID TUMORS OF MAMMARY GLANDS. CURRENT STATE OF THE PROBLEM

    A. D. Zikiryakhodzhaev

    2017-01-01

    Full Text Available Phylloid (leaf-shaped breast tumors are a rare disease and constitute 0.3–0.5% of all breast tumors. Due to the rare frequency of occurrence, as well as the small number of randomized studies that have been conducted on this pathology, there is currently no standardized approach to the diagnosis and treatment of phylloid tumors. The reports about these rare cases appearing in the literature are, as a rule, descriptive, which only emphasizes the difficulty of differential diagnosis, the development of the correct tactics for treating such patients. In connection with the rarity, it is very difficult to diagnose correctly this pathology, which requires a highly qualified doctor as a diagnostician in the initial contact with such a patient, and a pathologist doctor who establishes the final morphological diagnosis. Often, leaf-shaped tumors are mistaken for mammary fibroadenomas. Such difficulties in correct diagnosis in the preoperative period can lead to errors in the planning of treatment. Also, the recommendations for the treatment of patients with this diagnosis are not fully understood, since up to now there are no accepted treatment standards in both Russian and foreign recommendations. Due to the fact that this pathology of mammary glands is rare, the principles of treatment are based on small retrospective studies and clinical observations. In this review, we will discuss the results of major retrospective studies, including data on epidemiology, etiology, diagnostic approach, strategies and results of treatment of this complex group of breast pathologies.

  15. The determination of the mixing height. Current progress and problems

    Gryning, S.E.; Beyrich, F.; Batchvarova, E. [eds.

    1997-10-01

    This report contains extended abstracts of presentations given at a EURASAP Workshop on The Determination of the Mixing Height - Current Progress and Problems. The Workshop, initiated from discussions with Peter Builtjes, was held at Risoe National Laboratory 1-3 October 1997 within the framework of EURASAP (European Association for the Sciences of Air Pollution). The specific topics and chairpersons of the Workshop were: Theoretical Considerations (Sven-Erik Gryning), Mixing Height Estimation from Turbulence Measurements and In-Situ Soundings (Douw Steyn), Mixing Height Determination from NWP-Models (Han van Dop), Climatology and Global Aspects (Werner Klug), Mixing Height Determination from Remote Systems (Werner Klug), Verification of Mixing Height Parameterizations and Models (Frank Beyrich), Mixing Height over Complex Terrain (Ekaterina Batchvarova), Internal Boundary Layers: Mixing Height in Coastal Areas and Over Cities (Allen White). The discussion at the end of the Workshop was chaired by Robert Bornstein. (au)

  16. Radioactive residues. Current and prospective problems. Les residus radioactifs. Problems actuels et perspectives

    Gauvenet, A.

    1975-07-01

    After having described the principal characteristics of radioactive residues, the author examined the current problems posed by liquid and gaseous effluents and stressed that nuclear installations are definitely much less polluting, with an identical power output, than conventional power stations. Research programs have been undertaken in the face of the predictable increase in activity. The gist of the matter is to maintain the absorbed doses at their present level and to study the problem of compounds with a long lifetime, the accumulation of which would create considerable danger on a world scale. With respect to the stockpiling of wastes, the author described the various techniques currently used and cited studies in progress, some of which--such as vitrification--have already come into the first stages of application. After having noted that the waste problem undoubtedly constitutes a technical difficulty and perhaps even more so on the psychological plane, the author defined in conclusion the conditions that should be established so that this problem does not hinder the short- and long-term development of nuclear energy.

  17. Deformation of contact surfaces in a vacuum interrupter after high-current interruptions

    Wang, Haoran; Wang, Zhenxing, E-mail: zxwang@xjtu.edu.cn; Zhou, Zhipeng; Jiang, Yanjun; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-08-07

    In a high-current interruption, the contact surface in a vacuum interrupter might be severely damaged by constricted vacuum arcs causing a molten area on it. As a result, a protrusion will be initiated by a transient recovery voltage after current zero, enhancing the local electric field and making breakdowns occur easier. The objective of this paper is to simulate the deformation process on the molten area under a high electric field by adopting the finite element method. A time-dependent Electrohydrodynamic model was established, and the liquid-gas interface was tracked by the level-set method. From the results, the liquid metal can be deformed to a Taylor cone if the applied electric field is above a critical value. This value is correlated to the initial geometry of the liquid metal, which increases as the size of the liquid metal decreases. Moreover, the buildup time of a Taylor cone obeys the power law t = k × E{sup −3}, where E is the initial electric field and k is a coefficient related to the material property, indicating a temporal self-similar characteristic. In addition, the influence of temperature has little impact on the deformation but has great impact on electron emission. Finally, the possible reason to initiate a delayed breakdown is associated with the deformation. The breakdown does not occur immediately when the voltage is just applied upon the gap but is postponed to several milliseconds later when the tip is formed on the liquid metal.

  18. International Workshop on Current Problems in Condensed Matter

    Current Problems in Condensed Matter

    1998-01-01

    This volume contains the papers presented at the International Workshop on the Cur­ rent Problems in Condensed Matter: Theory and Experiment, held at Cocoyoc, More­ los, Mexico, during January 5-9, 1997. The participants had come from Argentina, Austria, Chile, England, France, Germany, Italy, Japan, Mexico, Switzerland, and the USA. The presentations at the Workshop provided state-of-art reviews of many of the most important problems, currently under study, in condensed matter. Equally important to all the participants in the workshop was the fact that we had come to honor a friend, Karl Heinz Bennemann, on his sixty-fifth birthday. This Festschrift is just a small measure of recognition of the intellectualleadership of Professor Bennemann in the field and equally important, as a sincere tribute to his qualities as an exceptional friend, college and mentor. Those who have had the privilege to work closely with Karl have been deeply touched by Karl's inquisitive scientific mind as well as by bis k...

  19. Conversion disorder: current problems and potential solutions for DSM-5.

    Stone, Jon; LaFrance, W Curt; Brown, Richard; Spiegel, David; Levenson, James L; Sharpe, Michael

    2011-12-01

    Conversion disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) describes neurological symptoms, including weakness, numbness and events resembling epilepsy or syncope, which can be positively identified as not being due to recognised neurological disease. This review combines perspectives from psychiatry, psychology and neurology to identify and discuss key problems with the current diagnostic DSM-IV criteria for conversion disorder and to make the following proposals for DSM-5: (a) abandoning the label "conversion disorder" and replacing it with an alternative term that is both theoretically neutral and potentially more acceptable to patients and practitioners; (b) relegating the requirements for "association of psychological factors" and the "exclusion of feigning" to the accompanying text; (c) adding a criterion requiring clinical findings of internal inconsistency or incongruity with recognised neurological or medical disease and altering the current 'disease exclusion' criteria to one in which the symptom must not be 'better explained' by a disease if present, (d) adding a 'cognitive symptoms' subtype. We also discuss whether conversion symptoms are better classified with other somatic symptom disorders or with dissociative disorders and how we might address the potential heterogeneity of conversion symptoms in classification. 2011 Elsevier Inc. All rights reserved.

  20. Current flow in a 3-terminal thin film contact with dissimilar materials and general geometric aspect ratios

    Zhang Peng; Hung, Derek M H; Lau, Y Y

    2013-01-01

    The current flow pattern, together with the contact resistance, is calculated analytically in a Cartesian 3-terminal thin film contact with dissimilar materials. The resistivities and the geometric dimensions in the individual contact members, as well as the terminal voltages, may assume arbitrary values. We show that the current flow patterns and the contact resistance may be conveniently decomposed into the even and odd solution. The even solution gives exclusively and totally the current flowing from the source to the gate. The odd solution gives exclusively and totally the current flowing from the source to the drain. Current crowding at the edges, and current partition in different regions are displayed. The analytic solutions are validated using a simulation code. The bounds on the variation of the contact resistance are given. This paper may be considered as the generalization of the transmission line model and the Kennedy-Murley model that were used extensively in the characterization of thin-film devices. For completeness, we include the general results for the cylindrical geometry, which are qualitatively similar to the even solution of the Cartesian geometry.

  1. Nonlinear time-series analysis of current signal in cathodic contact glow discharge electrolysis

    Allagui, Anis; Abdelkareem, Mohammad Ali; Rojas, Andrea Espinel; Bonny, Talal; Elwakil, Ahmed S.

    2016-01-01

    In the standard two-electrode configuration employed in electrolytic process, when the control dc voltage is brought to a critical value, the system undergoes a transition from conventional electrolysis to contact glow discharge electrolysis (CGDE), which has also been referred to as liquid-submerged micro-plasma, glow discharge plasma electrolysis, electrode effect, electrolytic plasma, etc. The light-emitting process is associated with the development of an irregular and erratic current time-series which has been arbitrarily labelled as “random,” and thus dissuaded further research in this direction. Here, we examine the current time-series signals measured in cathodic CGDE configuration in a concentrated KOH solution at different dc bias voltages greater than the critical voltage. We show that the signals are, in fact, not random according to the NIST SP. 800-22 test suite definition. We also demonstrate that post-processing low-pass filtered sequences requires less time than the native as-measured sequences, suggesting a superposition of low frequency chaotic fluctuations and high frequency behaviors (which may be produced by more than one possible source of entropy). Using an array of nonlinear time-series analyses for dynamical systems, i.e., the computation of largest Lyapunov exponents and correlation dimensions, and re-construction of phase portraits, we found that low-pass filtered datasets undergo a transition from quasi-periodic to chaotic to quasi-hyper-chaotic behavior, and back again to chaos when the voltage controlling-parameter is increased. The high frequency part of the signals is discussed in terms of highly nonlinear turbulent motion developed around the working electrode.

  2. INVESTIGATION OF PROPERTIES OF CURRENT COLLECTOR ELEMENTS AND THEIR EFFECT ON THE PERFORMANCE OF TRIBOSYSTEM «CONTACT WIRE - CURRENT COLLECTOR ELEMENT»

    Yu. L. Bolshakov

    2015-11-01

    Full Text Available Purpose. The paper is devoted to the detailed analysis of interrelations at the contact point of friction pair «contact wire – current collector insert». In the work it is necessary: 1 to examine quality of manufacturing of specimens of current collector elements from different manufacturers; 2 to narrow the range of hardness for carbon inserts; 3 to develop a technique of sorting carbon current collector inserts for the structural parameters. Methodology. The executed work was based on the use of the theory of reliability of technical systems and electromechanical processes. Findings. The paper studies the interrelation at the contact point of friction pair «contact wire – current col lector insert», the connection was established between the hardness and electrical resistivity. It is proposed to narrow the range of carbon inserts hardness. The method of sorting coal collector inserts in hardness was developed, and the research has revealed the discrepancy of current collector inserts with existing regulations. It was proposed to equip the pantographs slide with current collector elements using special scheme and to develop a specialized research facility, which will be possible to conduct studies of the interaction of the friction pair «contact wire – current collector insert». Originality. In the course of the study the current collector inserts the sharp structural heterogeneity and fluctuations of the density of the material along the length of the insert were established. The dependence between hardness of inserts and electrical resistivity was established. It was analyzed and concluded about the need to reduce the values of the normal range of hardness. Based on the results of the research, the experimental dependences were obtained and proposed the method for sorting carbon current collector inserts for the structural parameters. Practical value. The obtained results of coal current collector inserts define the need to use

  3. Some Current Problems in Optimisation of Radiation Protection System

    Franic, Z.; Prlic, I.

    2001-01-01

    Full text: The current system of radiation protection is generally based on recommendations promulgated in the International Commission on Radiological Protection (ICRP) publication 60. These principles and recommendations were subsequently adopted by the International Atomic Energy Agency (IAEA) in International Basic Safety Standards for Protection against Ionising Radiation and for the Safety of Radiation Sources (BSS). However, in recent years certain problems have arisen such as application of risk factors at low doses, use and interpretation of a collective dose, concept of dose commitment, optimisation of all types of occupational exposure and practices, implementation of ALARA approach in the common occupational as well as in quite complex situations etc. In this paper are presented some of the issues that have to be addressed in the development of the new ICRP Recommendations that are planned to be developed in next four or five years. As the new radiation protection philosophy shifts from society-based control of stochastic risks to an individual-based policy, consequently it will require introduction of modified approach to optimisation process and probably introduction of some new dosimetric quantities. (author)

  4. Current problems and perspectives of maintenance at NPPs

    Hevia Ruperez, F.; Garcia, R.; Manso Osuna, R.

    1994-01-01

    The highest levels of availability and efficiency for a plant in service, together with other, not less important, objectives such as improving plant safety, reliability and operability cannot be achieved if there is no adequate maintenance of plant systems and equipment. The combination of the large number of such system and equipment, diversity of their design, complexity of their interrelations and operation and maintenance requirements, make it difficult at times to obtain the right degree of technical and economic effectiveness. From the regulatory point of view, mention must be made of the Maintenance Rule (10/CFR/50.65) entitled ''Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants'' published on 10 July 1991 by the NRC. This Rule will come into force in the USA in 1996. This paper presents, on the one hand, a general view of the current status of NPP maintenance, enumerating the problems, difficulties and complications affecting its workability and, on the other, outlines new trends and methodologies (RAM, RCM, PRA, Remaining Lifetime Management, etc), for analysing and evaluating maintenance programmes, improving and optimizing them, and at the same time enhancing plant availability and lifetime. (Author)

  5. SCHOOLS AND CYBERBULLYING: PROBLEM PERCEPTION, CURRENT ACTIONS AND FUTURE NEEDS

    Heidi Vandebosch

    2014-06-01

    Full Text Available Cyberbullying is a common phenomenon amongst young people. It exhibits many similarities to traditional school bullying, with a potentially serious impact on the mental health and school functioning of victims. For this reason, action by schools is often recommended. The aim of this article is to provide a better picture of what schools are currently doing to address cyberbullying and of what schools will need to continue doing so in the future. An online survey was conducted among staff members of 309 primary and secondary schools in Flanders, which is the Dutch speaking part of Belgium. The questionnaire measured the schools’ experiences with cyberbullying and their perceived responsibility and efficacy in dealing with this issue as well as their concrete preventive, detective, and reactive actions. The results indicate that, although most schools are aware of relatively few cases of cyberbullying, they do consider cyberbullying to be a problem. Many schools consider it their duty to inform students about cyberbullying and to help find solutions to cyberbullying incidents involving students, even if they take place away from the school grounds or outside school hours. Although most schools organize concrete actions with regard to cyberbullying, they often seem uncertain about the appropriateness and effectiveness of their actions. They would welcome evidence-based intervention programmes that would appeal to their students.

  6. Electronic money in russia: current state and problems of development

    T. G. Bondarenko

    2016-01-01

    Full Text Available Article is devoted to urgent problems of non-cash methods of calculation development by using electronic money – as one of the modern economically developed state strategic tasks. On modern economic science strong influence appears informatization process. The control expansion tendency, influence and distribution of commerce due to informatization of society led to emergence of the new phenomenon – information economy. Information economy brought new economic events which owing to their novelty are insufficiently studied to life. It is possible to carry electronic money to such phenomena of modern network economy Relevance and, in our opinion, timeliness of this scientific work, consisting in novelty of this non-cash payment method, its prospects and innovation within non-cash methods of calculations. Authors set as the purpose – studying of problems and the prospects of development of electronic money in the Russian Federation. In article theoretical bases of electronic money functioning are described. Determinations and classifications dismissed non-cash a method, and also the principles of electronic money functioning are considered, the questions of their historical development are raised.Authors analyzed statistical data on development of electronic services and channels of their using. Features, benefits and shortcomings of the current state of the market of electronic money are studied. The emphasis on that fact that in modern conditions considerable number of economic actors perform the activities, both in the real environment of economy, and within the virtual environment that promotes expansion of methods of their customer interaction by means of technical devices of personal computers, mobile phones is placed. In article common problems and tendencies of payments with using an electronic money are designated, the research on assessment of the current state and the prospects of electronic money

  7. A two-dimensional finite element method for analysis of solid body contact problems in fuel rod mechanics

    Nissen, K.L.

    1988-06-01

    Two computer codes for the analysis of fuel rod behavior have been developed. Fuel rod mechanics is treated by a two-dimensional, axisymmetric finite element method. The program KONTAKT is used for detailed examinations on fuel rod sections, whereas the second program METHOD2D allows instationary calculations of whole fuel rods. The mechanical contact of fuel and cladding during heating of the fuel rod is very important for it's integrity. Both computer codes use a Newton-Raphson iteration for the solution of the nonlinear solid body contact problem. A constitutive equation is applied for the dependency of contact pressure on normal approach of the surfaces which are assumed to be rough. If friction is present on the contacting surfaces, Coulomb's friction law is used. Code validation is done by comparison with known analytical solutions for special problems. Results of the contact algorithm for an elastic ball pressing against a rigid surface are confronted with Hertzian theory. Influences of fuel-pellet geometry as well as influences of discretisation of displacements and stresses of a single fuel pellet are studied. Contact of fuel and cladding is calculated for a fuel rod section with two fuel pellets. The influence of friction forces between fuel and cladding on their axial expansion is demonstrated. By calculation of deformations and temperatures during an instationary fuel rod experiment of the CABRI-series the feasibility of two-dimensional finite element analysis of whole fuel rods is shown. (orig.) [de

  8. Effect of localized states on the current-voltage characteristics of metal-semiconductor contacts with thin interfacial layer

    Chattopadhyay, P.

    1994-10-01

    The role of discrete localized states on the current-voltage characteristics of metal-semiconductor contact is examined. It is seen that, because of these localized states, the logarithmic current vs voltage characteristics become nonlinear. Such nonlinearity is found sensitive to the temperature, and the energy and density of the localized states. The predicted temperature dependence of barrier height and the current-voltage characteristics are in agreement with the experimental results of Aboelfotoh [ Phys. Rev. B39, 5070 (1989)].

  9. Contact dermatitis is an unrecognized problem in the construction industry : Comparison of four different assessment methods

    Timmerman, Johan G; Heederik, Dick; Spee, Ton; van Rooy, Frits G; Krop, Esmeralda J M; Rustemeyer, Thomas; Smit, Lidwien A M

    2017-01-01

    BACKGROUND: A high contact dermatitis symptoms prevalence has been observed in Dutch construction workers. METHODS: Contact dermatitis was diagnosed by an expert panel using questionnaire data and photographs of 751 subjects' hands. A subset was evaluated by two occupational physicians. Their

  10. Advanced Curation: Solving Current and Future Sample Return Problems

    Fries, M.; Calaway, M.; Evans, C.; McCubbin, F.

    2015-01-01

    Advanced Curation is a wide-ranging and comprehensive research and development effort at NASA Johnson Space Center that identifies and remediates sample related issues. For current collections, Advanced Curation investigates new cleaning, verification, and analytical techniques to assess their suitability for improving curation processes. Specific needs are also assessed for future sample return missions. For each need, a written plan is drawn up to achieve the requirement. The plan draws while upon current Curation practices, input from Curators, the analytical expertise of the Astromaterials Research and Exploration Science (ARES) team, and suitable standards maintained by ISO, IEST, NIST and other institutions. Additionally, new technologies are adopted on the bases of need and availability. Implementation plans are tested using customized trial programs with statistically robust courses of measurement, and are iterated if necessary until an implementable protocol is established. Upcoming and potential NASA missions such as OSIRIS-REx, the Asteroid Retrieval Mission (ARM), sample return missions in the New Frontiers program, and Mars sample return (MSR) all feature new difficulties and specialized sample handling requirements. The Mars 2020 mission in particular poses a suite of challenges since the mission will cache martian samples for possible return to Earth. In anticipation of future MSR, the following problems are among those under investigation: What is the most efficient means to achieve the less than 1.0 ng/sq cm total organic carbon (TOC) cleanliness required for all sample handling hardware? How do we maintain and verify cleanliness at this level? The Mars 2020 Organic Contamination Panel (OCP) predicts that organic carbon, if present, will be present at the "one to tens" of ppb level in martian near-surface samples. The same samples will likely contain wt% perchlorate salts, or approximately 1,000,000x as much perchlorate oxidizer as organic carbon

  11. On a Solvability of Contact Problems with Visco-Plastic Friction in the Thermo-Visco-Plastic Bingham Rheology

    Nedoma, Jiří

    2006-01-01

    Roč. 22, č. 4 (2006), s. 484-499 ISSN 0167-739X Institutional research plan: CEZ:AV0Z10300504 Keywords : unilateral contact problem * local visco- plastic friction * thermo-visco- plastic Bingham rheology * FEM Subject RIV: BA - General Mathematics Impact factor: 0.722, year: 2006

  12. Chemical Disarmament: Current Problems in Implementing the Chemical Weapons Convention

    Matoušek, J.

    2006-03-01

    Full Text Available The Chemical Weapons Convention (CWC is briefly characterised by stressing its main pillars, such as verified destruction ofCWstockpiles and destruction/conversion ofCWproduction facilities (CWPFs, verified non-production of CW by the chemical industries, assistance and protection, and international cooperation. The CWC´s leading principle in defining theCW(protecting it generally against scientific and technological development, i. e. so called General Purpose Criterion is thoroughly elucidated showing its relation to the CWC´s sophisticated verification system. Status of implementation (as of August 2005 shows main data obligatory declared by the States Parties (SP, among them 6 possessors of CW stockpiles (Russia, USA, India, South Korea, Albania and Libya. From the declared 71 373 agent-tons, 12 889 have been destroyed, from the declared 8 679 M items of munitions (containers, 2 420 have been destroyed, which means that the anticipated 10 years deadline for CW destruction (after entry into force – EIF will be not managed. For Russia and USA the allowed extension by another 5 years has been already agreed. From the 64 CWPFs (operational after 1946, declared by 12 SPs, 53 have been certified as destroyed/converted. The Organisation for the Prohibition of Chemical Weapons (OPCW is briefly presented and main results of the First Review Conference (2003 analysed on the base of the adopted principal documents. Future problems of implementing the CWC are connected in the first line with its universality, because among 16 non-SPs, several countries (located mainly in the Near East and on the Korean peninsula are presumed to be CW-possessors. Special emphasis is laid on both, threats and benefits of the scientific and technological development for current implementing the CWC as well as of its implementation in future after all CW stockpiles have been destroyed.

  13. Contact dermatitis is an unrecognized problem in the construction industry: Comparison of four different assessment methods.

    Timmerman, Johan G; Heederik, Dick; Spee, Ton; van Rooy, Frits G; Krop, Esmeralda J M; Rustemeyer, Thomas; Smit, Lidwien A M

    2017-10-01

    A high contact dermatitis symptoms prevalence has been observed in Dutch construction workers. Contact dermatitis was diagnosed by an expert panel using questionnaire data and photographs of 751 subjects' hands. A subset was evaluated by two occupational physicians. Their diagnoses were compared to those of the expert panel. In addition, two self-reported questionnaire-based assessment methods were compared to the expert panel evaluation. Associations between contact dermatitis and determinants were assessed using log-binomial regression analysis. Contact dermatitis prevalence was high: 61.4% (expert panel's diagnosis) and 32.9% (self-reported). Agreement between occupational physicians and the expert panel was low but increased after training. Washing hands with solvents and performing job-related tasks at home were related to contact dermatitis. Contact dermatitis prevalence among construction workers is high. Recognition of contact dermatitis by occupational physicians is poor but can be improved by training. Awareness of skin disorders should be raised. © 2017 Wiley Periodicals, Inc.

  14. Current problems in applied mathematics and mathematical physics

    Samarskii, A. A.

    Papers are presented on such topics as mathematical models in immunology, mathematical problems of medical computer tomography, classical orthogonal polynomials depending on a discrete variable, and boundary layer methods for singular perturbation problems in partial derivatives. Consideration is also given to the computer simulation of supernova explosion, nonstationary internal waves in a stratified fluid, the description of turbulent flows by unsteady solutions of the Navier-Stokes equations, and the reduced Galerkin method for external diffraction problems using the spline approximation of fields.

  15. Spin currents in a normal two-dimensional electron gas in contact with a spin-orbit interaction region

    Sukhanov, Aleksei A; Sablikov, Vladimir A; Tkach, Yurii Ya

    2009-01-01

    Spin effects in a normal two-dimensional (2D) electron gas in lateral contact with a 2D region with spin-orbit interaction are studied. The peculiarity of this system is the presence of spin-dependent scattering of electrons from the interface. This results in an equilibrium edge spin current and nontrivial spin responses to a particle current. We investigate the spatial distribution of the spin currents and spin density under non-equilibrium conditions caused by a ballistic electron current flowing normal or parallel to the interface. The parallel electron current is found to generate a spin density near the interface and to change the edge spin current. The perpendicular electron current changes the edge spin current proportionally to the electron current and produces a bulk spin current penetrating deep into the normal region. This spin current has two components, one of which is directed normal to the interface and polarized parallel to it, and the second is parallel to the interface and is polarized in the plane perpendicular to the contact line. Both spin currents have a high degree of polarization (∼40-60%).

  16. Current problems of prevention diagnosis and treatment of radiation sickness

    Gus'kova, A.K.

    1986-01-01

    Causes of increasing interest to the problems of prevention, diagnosis and treatment of radiation sickness are presented. On the basis of recent publications some new aspects as quantitative criteria in radiobiology, organization problems of medical aid at radiation incidents estimation of efficiency of preventive medicine and radiation sickness therapy, theoretical development of radiotherapy of different organs et al., are characterized

  17. Problems and limitations of eddy current tube inspection

    Ilham Mukriz Zainal Abidin; Khairul Anuar Mohd Salleh; Mohamed Hairul Hasmoni

    2003-01-01

    Incomplete appreciation of eddy current limitations has contributed to both under-utilization and misapplication of the technique. A brief review on the physical principle of eddy current is presented. Eddy current technique in identifying inhomogeneity in tested tubes is discussed, highlighting its limitation in distinguishing between real pit type defects and other mundane anomalies. The variables responsible for limitation in eddy current tube inspection are discussed and alternative approaches, where they exist, are suggested. (Author)

  18. Analysis of a Dynamic Viscoelastic Contact Problem with Normal Compliance, Normal Damped Response, and Nonmonotone Slip Rate Dependent Friction

    Mikaël Barboteu

    2016-01-01

    Full Text Available We consider a mathematical model which describes the dynamic evolution of a viscoelastic body in frictional contact with an obstacle. The contact is modelled with a combination of a normal compliance and a normal damped response law associated with a slip rate-dependent version of Coulomb’s law of dry friction. We derive a variational formulation and an existence and uniqueness result of the weak solution of the problem is presented. Next, we introduce a fully discrete approximation of the variational problem based on a finite element method and on an implicit time integration scheme. We study this fully discrete approximation schemes and bound the errors of the approximate solutions. Under regularity assumptions imposed on the exact solution, optimal order error estimates are derived for the fully discrete solution. Finally, after recalling the solution of the frictional contact problem, some numerical simulations are provided in order to illustrate both the behavior of the solution related to the frictional contact conditions and the theoretical error estimate result.

  19. Current-Voltage Characteristics of the Metal / Organic Semiconductor / Metal Structures: Top and Bottom Contact Configuration Case

    Šarūnas MEŠKINIS

    2013-03-01

    Full Text Available In present study five synthesized organic semiconductor compounds have been used for fabrication of the planar metal / organic semiconductor / metal structures. Both top electrode and bottom electrode configurations were used. Current-voltage (I-V characteristics of the samples were investigated. Effect of the hysteresis of the I-V characteristics was observed for all the investigated samples. However, strength of the hysteresis was dependent on the organic semiconductor used. Study of I-V characteristics of the top contact Al/AT-RB-1/Al structures revealed, that in (0 – 500 V voltages range average current of the samples measured in air is only slightly higher than current measured in nitrogen ambient. Deposition of the ultra-thin diamond like carbon interlayer resulted in both decrease of the hysteresis of I-V characteristics of top contact Al/AT-RB-1/Al samples. However, decreased current and decreased slope of the I-V characteristics of the samples with diamond like carbon interlayer was observed as well. I-V characteristic hysteresis effect was less pronounced in the case of the bottom contact metal/organic semiconductor/metal samples. I-V characteristics of the bottom contact samples were dependent on electrode metal used.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3816

  20. Radiological protection in medicine: Current problems in Indonesia

    Hiswara, E.

    2001-01-01

    The medical applications of ionizing radiation in Indonesia have been introduced in the early 20th century. Since then it dominates the application of radiation in various fields. By several regulations, the government has tried to control these applications. However, some problems are still persisting. This paper presents the safety-related regulations that are in place in Indonesia, authorization status regarding medical applications, the existing problems and the efforts to tackle them. Even though the funds are always the scapegoat, it is believed that the real reason for all problems concerning radiation protection in Indonesia is lack of safety culture among the users. (author)

  1. Certain problems in the current theory of gravitation

    Markov, M. A.

    1984-04-01

    A number of problems (considered by the author to be the most significant) connected with the possible role of gravitation in the elementary-particle physics and cosmology are examined. Particular attention is given to the problems of self-energy, the limit mass of elementary particles, maximons and the evolution of the universe, the origin of the universe, and the physical meaning of Planck's length.

  2. The current account as a dynamic portfolio choice problem

    Didier, Tatiana; Lowenkron, Alexandre

    2009-01-01

    The current account can be understood as the outcome of investment decisions made by domestic and foreign investors. These decisions can be decomposed into a portfolio rebalancing and a portfolio growth component. This paper provides empirical evidence of the importance of portfolio rebalancing for the dynamics of the current account. The authors evaluate the predictions of a partial-equil...

  3. Current problems regarding abortion, prenatal genetic testing and managing pregnancy

    Klajn-Tatić Vesna

    2011-01-01

    Full Text Available Current ethical and legal issues with regard to abortion, prenatal genetic testing and managing pregnancy are discussed in this paper. These problems are considered from the legal theory point of view as well as from the standpoint of the Serbian Law, the European Convention for the Protection of Human Rights and Fundamental Freedoms, European Court of Human Rights, legal regulations of several EU countries, the USA, Japan, and their judicial practice. First, the pregnancy termination standards that exist in Serbia are introduced. Then the following issues are explained separately: the pro life and pro choice approaches to abortion; abortion according to the legal approach as a way of survival; the moral and legal status of the fetus; prenatal genetic testing, and finally matters regarding managing pregnancy today. Moral and legal principals of autonomy, namely freedom of choice of the individual, privacy and self-determination give women the right to terminate unwanted pregnancies. In addition, the basic question is whether the right of the woman to abortion clashes with the rights of others. Firstly, with the right of the "fetus to life". Secondly, with the right of the state to intervene in the interest of protecting "the life of the fetus". Third, with the rights of the woman’s partner. The fetus has the moral right to life, but less in relation to the same right of the woman as well as in relation to her right to control her life and her physical and moral integrity. On the other hand, the value of the life of the fetus increases morally and legally with the maturity of gestation; from the third trimester, the interest of the state prevails in the protection of the "life of the fetus" except when the life or health of the pregnant woman are at risk. As regards the rights of the woman’s partner, namely the husband’s opinion, there is no legal significance. The law does not request his participation in the decision on abortion because

  4. Obtaining macroscopic quantities for the contact line problem from Density Functional Theory using asymptotic methods

    Sibley, David; Nold, Andreas; Kalliadasis, Serafim

    2015-11-01

    Density Functional Theory (DFT), a statistical mechanics of fluids approach, captures microscopic details of the fluid density structure in the vicinity of contact lines, as seen in computations in our recent study. Contact lines describe the location where interfaces between two fluids meet solid substrates, and have stimulated a wealth of research due to both their ubiquity in nature and technological applications and also due to their rich multiscale behaviour. Whilst progress can be made computationally to capture the microscopic to mesoscopic structure from DFT, complete analytical results to fully bridge to the macroscale are lacking. In this work, we describe our efforts to bring asymptotic methods to DFT to obtain results for contact angles and other macroscopic quantities in various parameter regimes. We acknowledge financial support from European Research Council via Advanced Grant No. 247031.

  5. Automatic contact algorithm in ppercase[dyna3d] for crashworthiness and impact problems

    Whirley, Robert G.; Engelmann, Bruce E.

    1994-01-01

    This paper presents a new approach for the automatic definition and treatment of mechanical contact in explicit non-linear finite element analysis. Automatic contact offers the benefits of significantly reduced model construction time and fewer opportunities for user error, but faces significant challenges in reliability and computational costs. Key aspects of the proposed new method include automatic identification of adjacent and opposite surfaces in the global search phase, and the use of a well-defined surface normal which allows a consistent treatment of shell intersection and corner contact conditions without adhoc rules. The paper concludes with three examples which illustrate the performance of the newly proposed algorithm in the public ppercase[dyna3d] code. ((orig.))

  6. Point-contact spectroscopy of unsaturates oxides of transition metals and the problem of zero anomalies

    Tulina, N.A.

    1985-01-01

    A study was made of point-contact spectra of oxides WO 2 , ReO 3 , MoO 2 with metallic conductivity. It is shown that zero anomalies often observed in transition metal spectra are due to a higher-type oxide interlayer in the vicinity of a point contact. There are no zero anomalies in the point-contact spectra of heterocontacts Zn-MoO 2 (broken crystal) obtained directly in a helium cryostal. When studying such heterocontacts, major maxima of electron- phonon interaction in MoO 2 were determined on the energy scale hω sub(TA) approximately 28 MeV, hω sub(LA) approximately 41 MeV

  7. Modelling of contact problems involved in ensuring the safety of rail transport

    Edward Rydygier

    2013-12-01

    Full Text Available Background: Mathematical modelling aids diagnostics the track and rolling stock, as it often for technical reasons it is not possible to obtain a complete set of measurement data required to diagnose the rail and wheel deformation caused by the impact of a rail vehicle on the track. The important issue in a railway diagnostics is to study the effects of contact wheel and rail. Diagnostics investigations of track and rolling stock have a fundamental role in ensuring the safety of transport of passengers and goods. The aim of the study presented in the paper was to develop simulation methods of mathematical modelling of the wheel-rail system useful in the diagnostics of the track and a railway vehicle. Methods: In the paper two ways of modelling were presented and discussed. One of these ways is the method which consists in reducing the contact issue to field issue and solving the identification of the field source in 2-D system. Also presented a different method designed on the basis of the methods using one period energy concept. This method is adapted for modelling the dynamics of the contact wheel-rail for the normal force. It has been shown that the developed modelling methods to effectively support the study on the effects of mechanical and thermal of contact wheel-rail and contribute to the safety of operations.  Results and conclusions:  In the case of field sources identifications two specific issues were examined: the issue of rail torsion and the identification of heat sources in the rail due to exposure the rolling contact wheel-rail. In the case of the method using one period energy concept it was demonstrated the usefulness of this method to the study of energy processes in the contact wheel-rail under the normal periodic force. The future direction of research is to establish cooperation with research teams entrusted with the diagnostic measurements of track and rolling stock.  

  8. Spin-polarized currents in the tunnel contact of a normal conductor and a two-dimensional topological insulator

    Sukhanov, A. A.; Sablikov, V. A.

    2013-01-01

    The spin filtering of electrons tunneling from the edge states of a two-dimensional topological insulator into a normal conductor under a magnetic field (external or induced due to proximity to a magnetic insulator) is studied. Calculations are performed for a tunnel contact of finite length between the topological insulator and an electronic multimode quantum strip. It is shown that the flow of tunneling electrons is split in the strip, so that spin-polarized currents arise in its left and right branches. These currents can be effectively controlled by the contact voltage and the chemical potential of the system. The presence of a magnetic field, which splits the spin subbands of the electron spectrum in the strip, gives rise to switching of the spin current between the strip branches

  9. Contact Problem for an Elastic Layer on an Elastic Half Plane Loaded by Means of Three Rigid Flat Punches

    T. S. Ozsahin

    2013-01-01

    Full Text Available The frictionless contact problem for an elastic layer resting on an elastic half plane is considered. The problem is solved by using the theory of elasticity and integral transformation technique. The compressive loads P and Q (per unit thickness in direction are applied to the layer through three rigid flat punches. The elastic layer is also subjected to uniform vertical body force due to effect of gravity. The contact along the interface between elastic layer and half plane is continuous, if the value of the load factor, λ, is less than a critical value, . In this case, initial separation loads, and initial separation points, are determined. Also the required distance between the punches to avoid any separation between the punches and the elastic layer is studied and the limit distance between punches that ends interaction of punches is investigated for various dimensionless quantities. However, if tensile tractions are not allowed on the interface, for the layer separates from the interface along a certain finite region. Numerical results for distance determining the separation area, vertical displacement in the separation zone, contact stress distribution along the interface between elastic layer and half plane are given for this discontinuous contact case.

  10. Terminology of economics in Albanian: Current state, problems and tasks

    Mulaj, Isa

    2012-01-01

    The primary aim of this paper was to analyze the state of terminology of economics in Albanian language, and depending on the problems identified, to address some recommendations as tasks that are deemed necessary for future research that would contribute to its standardization. The paper begun from the hypothesis that the terminology in question is relatively rich, but finds that academic and scientific research are very limited or largely neglected, thus creating a vacuum in its broader and...

  11. Unsolved problems in biology--The state of current thinking.

    Dev, Sukhendu B

    2015-03-01

    Many outstanding problems have been solved in biology and medicine for which scientists have been awarded prestigious prizes including the Nobel Prize, Lasker Award and Breakthrough Prizes in life sciences. These have been the fruits of years of basic research. From time to time, publications have appeared listing "unsolved" problems in biology. In this article, I ask the question whether it is possible to have such a list, if not a unique one, at least one that is analogous to the Millennium Prize in mathematics. My approach to finding an answer to this question was to gather views of leading biologists. I have also included my own views. Analysis of all the responses received over several years has convinced me that it is difficult, but not impossible, to have such a prize. Biology is complex and very interdisciplinary these days at times involving large numbers of teams, unlike mathematics, where Andrew Wiles spent seven years in complete isolation and secrecy solving Fermat's last theorem. Such an approach is simply not possible in biology. Still I would like to suggest that a similar prize can be established by a panel of distinguished scientists. It would be awarded to those who solved one of the listed problems in biology that warrant a verifiable solution. Despite many different opinions, I found that there is some commonality in the responses I received - I go on to discuss what these are and how they may impact future thinking. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Shape optimization in 2D contact problems with given friction and a solution-dependent coefficient of friction

    Haslinger, J.; Outrata, Jiří; Pathó, R.

    2012-01-01

    Roč. 20, č. 1 (2012), s. 31-59 ISSN 1877-0533 R&D Projects: GA AV ČR IAA100750802 Institutional research plan: CEZ:AV0Z10750506 Institutional support: RVO:67985556 Keywords : shape optimization * Signorini problem * model with given frinction * solution-dependent coefficient of friction * mathematical probrams with equilibrium constraints Subject RIV: BA - General Mathematics Impact factor: 1.036, year: 2012 http://library.utia.cas.cz/separaty/2012/MTR/outrata-shape optimization in 2d contact problems with given friction and a solution-dependent coefficient of friction .pdf

  13. Power Quality Problems Due to Transformer Inrush Current

    Tokić, A.; Uglešić, I.

    2017-01-01

    Transformer energization can produce a large nonsinuoidal inrush current which contains both odd and higher order harmonic components that can put transformer winding under mechanical stress. Additionally, they can cause irregular tripping of harmonic protection relays. Furthermore, in relatively weak power systems, such as is the Bosnian system, the superposition of harmonic components with system resonance frequencies may produce temporary overvoltages (TOV). Transformer wind...

  14. Current problems of foreign practice-related educational psychology

    A.D. Andreeva

    2012-09-01

    Full Text Available The article regards the questions of scientific-methodological provision of psychologist’s activity in an educational settlement which are urgent for the activity of practical educational psychologist in Russia as well. The presented information concerns the psychologist’s particular strands of work which can be both developing (development of ABM and psycho-correcting (reasons and forms of school phobias, bullying displays, lying. The ethical problems of psychologist’s work with families namely in case of the parent-child conflicts is also reviewed in the article.

  15. Existence and uniqueness results for a class of dynamic elasto-plastic contact problems

    Krejčí, Pavel; Petrov, A.

    2013-01-01

    Roč. 408, č. 1 (2013), s. 125-139 ISSN 0022-247X R&D Projects: GA ČR GAP201/10/2315 Institutional support: RVO:67985840 Keywords : contact with friction * elasto-plasticity * hysteresis operators Subject RIV: BA - General Mathematics Impact factor: 1.119, year: 2013 http://www.sciencedirect.com/science/article/pii/S0022247X13004952

  16. Reliable Solution of a Unilateral Contact Problem with Friction and Uncertain Data in Thermo-Elasticity

    Hlaváček, Ivan; Nedoma, Jiří

    2005-01-01

    Roč. 67, - (2005), s. 559-580 ISSN 0378-4754 R&D Projects: GA ČR GA201/01/1200; GA MŠk OK 407 Grant - others:COPERNICUS-HIPERGEOS II(XE) KIT 977006 Institutional research plan: CEZ:AV0Z1030915 Keywords : unilateral contact * steady-state heat flow * Coulomb friction * finite element analysis * radioactive waste repositories Subject RIV: BA - General Mathematics Impact factor: 0.554, year: 2005

  17. SCHOOLS AND CYBERBULLYING: PROBLEM PERCEPTION, CURRENT ACTIONS AND FUTURE NEEDS

    Heidi Vandebosch; Karolien Poels; Gie Deboutte

    2014-01-01

    Cyberbullying is a common phenomenon amongst young people. It exhibits many similarities to traditional school bullying, with a potentially serious impact on the mental health and school functioning of victims. For this reason, action by schools is often recommended. The aim of this article is to provide a better picture of what schools are currently doing to address cyberbullying and of what schools will need to continue doing so in the future. An online survey was conducted among staff memb...

  18. Current problems of nuclear power radiation ecology and hygiene

    Vorob' ev, E I; Il' in, L A; Knizhnikov, V A; Aleksakhin, R M

    1979-10-01

    Perspectiveness of different kinds of energetics is mainly defined by their effect on environment and human health. Hygiene and ecology at present time can not give an objective characteristic of detriment because of the effluents from the fuel-energy cycle facilities, especially from facilities of the traditional energetics. The role of the radiactive effluents into environment is defined by their possible effect on the human health, but not the ecological effects. Meanwhile, the development of the principles of ecological normalization is an actual problem. It is important to carry out a quantitative stady of the dose-effect dependencies of the effluents of cancerogens of the physical and chemical nature into environment. It is advisable to estimate the possible effect of cancerogens from the positions of thresholdlessness of their action.

  19. Captive breeding of pangolins: current status, problems and future prospects

    Hua, Liushuai; Gong, Shiping; Wang, Fumin; Li, Weiye; Ge, Yan; Li, Xiaonan; Hou, Fanghui

    2015-01-01

    Abstract Pangolins are unique placental mammals with eight species existing in the world, which have adapted to a highly specialized diet of ants and termites, and are of significance in the control of forest termite disaster. Besides their ecological value, pangolins are extremely important economic animals with the value as medicine and food. At present, illegal hunting and habitat destruction have drastically decreased the wild population of pangolins, pushing them to the edge of extinction. Captive breeding is an important way to protect these species, but because of pangolin’s specialized behaviors and high dependence on natural ecosystem, there still exist many technical barriers to successful captive breeding programs. In this paper, based on the literatures and our practical experience, we reviewed the status and existing problems in captive breeding of pangolins, including four aspects, the naturalistic habitat, dietary husbandry, reproduction and disease control. Some recommendations are presented for effective captive breeding and protection of pangolins. PMID:26155072

  20. Captive breeding of pangolins: current status, problems and future prospects.

    Hua, Liushuai; Gong, Shiping; Wang, Fumin; Li, Weiye; Ge, Yan; Li, Xiaonan; Hou, Fanghui

    2015-01-01

    Pangolins are unique placental mammals with eight species existing in the world, which have adapted to a highly specialized diet of ants and termites, and are of significance in the control of forest termite disaster. Besides their ecological value, pangolins are extremely important economic animals with the value as medicine and food. At present, illegal hunting and habitat destruction have drastically decreased the wild population of pangolins, pushing them to the edge of extinction. Captive breeding is an important way to protect these species, but because of pangolin's specialized behaviors and high dependence on natural ecosystem, there still exist many technical barriers to successful captive breeding programs. In this paper, based on the literatures and our practical experience, we reviewed the status and existing problems in captive breeding of pangolins, including four aspects, the naturalistic habitat, dietary husbandry, reproduction and disease control. Some recommendations are presented for effective captive breeding and protection of pangolins.

  1. Captive breeding of pangolins: current status, problems and future prospects

    Liushuai Hua

    2015-06-01

    Full Text Available Pangolins are unique placental mammals with eight species existing in the world, which have adapted to a highly specialized diet of ants and termites, and are of significance in the control of forest termite disaster. Besides their ecological value, pangolins are extremely important economic animals with the value as medicine and food. At present, illegal hunting and habitat destruction have drastically decreased the wild population of pangolins, pushing them to the edge of extinction. Captive breeding is an important way to protect these species, but because of pangolin’s specialized behaviors and high dependence on natural ecosystem, there still exist many technical barriers to successful captive breeding programs. In this paper, based on the literatures and our practical experience, we reviewed the status and existing problems in captive breeding of pangolins, including four aspects, the naturalistic habitat, dietary husbandry, reproduction and disease control. Some recommendations are presented for effective captive breeding and protection of pangolins.

  2. Current problems of nuclear power radiation ecology and hygiene

    Vorob'ev, E.I.; Il'in, L.A.; Knizhnikov, V.A.; Aleksakhin, R.M.

    1979-01-01

    Perspectiveness of different kinds of energetics is mainly defined by their effect on environment and human health. Hygiene and ecology at present time can not give an objective characteristic of detriment because of the effluents from the fuel-energy cycle facilities, especially from facilities of the traditional energetics. The role of the radiactive effluents into environment is defined by their possible effect on the human health, but not the ecological effects. Meanwhile, the development of the principles of ecological normalization is an actual problem. It is important to carry out a quantitative stady of the dose-effect dependencies of the effluents of cancerogens of the physical and chemical nature into environment. It is advisable to estimate the possible effect of cancerogens from the positions of thresholdlessness of their action

  3. Current problems associated with nuclear plant construction contracts

    Albano, Raffaele.

    1977-01-01

    The expansion of nuclear electricity generating programmes has brought to the fore the problems associated with construction of this type of power plant. The paper analyses the contracts for such construction and describes the most common, the turnkey contract. The present tendency is to limit the scope of turnkey contracts to the nuclear system or simply to the reactor and this is especially common in advanced nuclear countries such as the US, Canada, Japan, UK and France, and this is also the case in Italy where the question of contracting nuclear plants is debated. In Germany the power utilities hold a large number of shares in the manufacturing industry and the turnkey contract is therefore more economically attractive. A detailed description of the contracting procedure is provided, including the suppliers' and purchasers' responsibilities, plant commissioning tests and handing over of the plant to the operator. (NEA) [fr

  4. Problems of the current law concerning official plan approval

    Bluemel, W.

    1986-01-01

    The booklet presents lectures held in October 1985 at the Speyer University for Administration Science, on the subject of the law concerning official plan approval. The lectures have been selected for their common interest in the requirements of nature conservation and landscape protection. These requirements and the current practice of plan approval procedure are the main issue of the lectures which discuss aspects of environmental impact statements, consideration of ecological requirements, and the role of the landscape conservation plan accompanying official project planning documents. (HSCH) [de

  5. A contact-less method to evaluate the state of charge of nickel batteries using Foucault's eddy currents

    Mancier, V.; Metrot, A.; Willmann, P.

    A nickel hydroxide electrode and a commercial battery have been studied by a new and contact-less impedance method, based on Foucault's eddy currents, with the aim of determining their state of charge. Four different current line distributions have been employed and the impedance versus time graphs obtained show a linear variation of this impedance during charge and discharge for all configurations. This new method allows the determination of the state of charge and, furthermore some "artifacts" obvious on these graphs may be useful to detect a deterioration of the studied material.

  6. [Transplantation in diabetes type 1--current problems and perspectives].

    Wasikowa, Renata; Noczyńska, Anna; Basiak, Aleksander

    2004-01-01

    Diabetes type 1 is, as we know, a chronic progressive disease, which requires a substitutional therapy with insulin for the whole life. The cause is a definite destruction of the pancreatic beta cells. For many years there have been intensive investigations on the possibility to obtain a complete, persistent withdrawal of the symptoms. Substitution of the destroyed, not active cells, could take place after transplantation of the whole pancreas, transplantation of pancreatic islets or transplantation of stem cells. This is now the only method which may cause an independence from exogenous insulin, persistent normoglycemia, normal HbA1c level, without risk of hypoglycemia. Pancreas and islets transplantations, however, are connected till now with the necessity of an immunosuppressive therapy for the whole life, with the toxicity of the drugs, incidence of frequent infections and malignancy. Pancreas transplantation is a serious surgical intervention, connected with numerous risks and complications, considerably less risk appears in islet cell transplantations. Since 2000 exclusively islet cell transplantations have been performed. One of the leading centers is Edmonton, where professor Shapiro prepared the so called. Edmonton protocol which is characterized by using corticosteroid-free immunosuppressive drugs, islet cells from two or more donors, repeated till the attainment of insulin dependence. A problem now is that the islets are obtained from cadavers. Therefore intensive research is conducted for alternative sources of beta cells. At this moment it is mostly preferred for receiving a sufficient number of insulin producing cells to develop stem cells with a subsequent differentiation to insulin producing cells. The mentioned cells have an unlimited ability of reproduction, in this case also immunosuppressive therapy is not necessary. Alternative sources of beta cells are cells achieved on the genetic engineering, embryonic or adult somatic stem cells. It is

  7. [The current state of the brain-computer interface problem].

    Shurkhay, V A; Aleksandrova, E V; Potapov, A A; Goryainov, S A

    2015-01-01

    It was only 40 years ago that the first PC appeared. Over this period, rather short in historical terms, we have witnessed the revolutionary changes in lives of individuals and the entire society. Computer technologies are tightly connected with any field, either directly or indirectly. We can currently claim that computers are manifold superior to a human mind in terms of a number of parameters; however, machines lack the key feature: they are incapable of independent thinking (like a human). However, the key to successful development of humankind is collaboration between the brain and the computer rather than competition. Such collaboration when a computer broadens, supplements, or replaces some brain functions is known as the brain-computer interface. Our review focuses on real-life implementation of this collaboration.

  8. Cosmic gamma-ray background radiation. Current understandings and problems

    Inoue, Yoshiyuki

    2015-01-01

    The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space telescope has recently measured it at 0.1-820 GeV and revealed that the cosmic GeV gamma-ray background is composed of blazars, radio galaxies, and star-forming galaxies. However, Fermi still leaves the following questions. Those are dark matter contribution, origins of the cosmic MeV gamma-ray background, and the connection to the IceCube TeV-PeV neutrino events. In this proceeding, I will review the current understandings of the cosmic gamma-ray background and discuss future prospects of cosmic gamma-ray background radiation studies. (author)

  9. The concept of electronegativity. The current state of the problem

    Cherkasov, Artem R; Galkin, Vladimir I; Zueva, Ekaterina M; Cherkasov, Rafael A

    1998-01-01

    A systematic account is given of the current ideas about atomic and group electronegativities and the trends in the development of the concept of electronegativity are analysed. Attention is concentrated on the latest approaches to the definition of electronegativity - the concept of 'orbital' electronegativities and the density functional theory. A procedure is proposed for the determination of 'inductive' electronegativities, which permits a correct theoretical calculation of the electronegativity of a substituent from the electronegativities of individual atoms and the steric structure. It is shown that the approach developed has a series of important advantages - for example, it makes it possible to calculate the group electronegativities of isomeric substituents avoiding the principle of the equalisation of electronegativities. A survey of literature data and generalisation of the method proposed by the authors have made it possible to formulate the concept of electronegativity as an unchanging fundamental immanent characteristic of a chemical element. The bibliography includes 222 references.

  10. Mixed arrays - problems with current methods and rules

    Mennerdahl, D.

    1987-01-01

    Simplified methods are used to control the criticality safety of mixed arrays (non-identical units) in storage or in transport. The basis for these methods is that the analyses of arrays of identical units are sufficient for drawing proper conclusions on mixed arrays. In a recent study of the rules for transport, two general flaws in such methods have been identified. One flaw is caused by increased neutron return rate to the central part of the array. The other flaw is caused by increased neutron coupling between two or more fissile units in an array. In both cases, replacement of fissile units with other units, which appear to be less reactive, can lead to criticality. This paper shows that the two flaws are common in also in current methods used for storage of fissile materials. (author)

  11. [Current situation and existing problems of acupuncture for primary hypertension].

    Zhang, Lili; Wei, Pengfei; Chen, Shaozong

    2018-03-12

    To analyze the present situation and existing problems of acupuncture for primary hypertension (PH) based on clinical research literature in recent 20 years. The clinical research literature regarding acupuncture for PH were searched from China National Knowledge Infrastructure (CNKI), VIP data network (VIP) and Wanfang database from 1997 through 2016; a total of 218 papers met the inclusive criteria. Microsoft Excel and Apriori algorithm of SPSS Clementine software were applied to analyze the data. The main acupoints of acupuncture for PH were Taichong (LR 3), Quchi (LI 11), Zusanli (ST 36) and Hegu (LI 4), but its support degree was only 12.21%. 127 papers were randomized controlled trials, accounting for 58.26%. 158 papers had clear diagnostic criteria, accounting for 72.48%. 138 papers had clear efficacy evaluation criteria, accounting for 63.30%. Only 5.05% of the papers were classified as high-quality literature by using Jadad scale. In recent 20 years, some rules existed in acupoint selection for PH, but the support degree was low so it could not accurately guide clinical treatment. Although the clinical literature quality of acupuncture for PH was gradually increasing, the proportion of high-quality literature was low, therefore modern medical research model and foreign similar research should be followed to design a more rigorous trial protocol. As a result, the quality of clinical research is increased to provide reference for future clinical treatment.

  12. Shift Work and Health: Current Problems and Preventive Actions

    Giovanni Costa

    2010-12-01

    Full Text Available The paper gives an overview of the problems to be tackled nowadays by occupational health with regards to shift work as well as the main guidelines at organizational and medical levels on how to protect workers’ health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general populations, all of which involve more and more people in continuous assistance and control of work processes over the 24 hours in a day. The large increase of epidemiological and clinical studies on this issue document the severity of this risk factor on human health and well being, at both social and psychophysical levels, starting from a disruption of biological circadian rhythms and sleep/wake cycle and ending in several psychosomatic troubles and disorders, likely also including cancer, and extending to impairment of performance efficiency as well as family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria and careful health surveillance and social support for shift workers are important preventive and corrective measures that allow people to keep working without significant health impairment.

  13. Non-contact current and voltage sensor having detachable housing incorporating multiple ferrite cylinder portions

    Carpenter, Gary D.; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C.; Schappert, Michael A.

    2016-04-26

    A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing formed from two portions that mechanically close around the wire and that contain the current and voltage sensors. The current sensor is a ferrite cylinder formed from at least three portions that form the cylinder when the sensor is closed around the wire with a hall effect sensor disposed in a gap between two of the ferrite portions along the circumference to measure current. A capacitive plate or wire is disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

  14. Defining the value of injection current and effective electrical contact area for EGaIn-based molecular tunneling junctions.

    Simeone, Felice C; Yoon, Hyo Jae; Thuo, Martin M; Barber, Jabulani R; Smith, Barbara; Whitesides, George M

    2013-12-04

    Analysis of rates of tunneling across self-assembled monolayers (SAMs) of n-alkanethiolates SCn (with n = number of carbon atoms) incorporated in junctions having structure Ag(TS)-SAM//Ga2O3/EGaIn leads to a value for the injection tunnel current density J0 (i.e., the current flowing through an ideal junction with n = 0) of 10(3.6±0.3) A·cm(-2) (V = +0.5 V). This estimation of J0 does not involve an extrapolation in length, because it was possible to measure current densities across SAMs over the range of lengths n = 1-18. This value of J0 is estimated under the assumption that values of the geometrical contact area equal the values of the effective electrical contact area. Detailed experimental analysis, however, indicates that the roughness of the Ga2O3 layer, and that of the Ag(TS)-SAM, determine values of the effective electrical contact area that are ~10(-4) the corresponding values of the geometrical contact area. Conversion of the values of geometrical contact area into the corresponding values of effective electrical contact area results in J0(+0.5 V) = 10(7.6±0.8) A·cm(-2), which is compatible with values reported for junctions using top-electrodes of evaporated Au, and graphene, and also comparable with values of J0 estimated from tunneling through single molecules. For these EGaIn-based junctions, the value of the tunneling decay factor β (β = 0.75 ± 0.02 Å(-1); β = 0.92 ± 0.02 nC(-1)) falls within the consensus range across different types of junctions (β = 0.73-0.89 Å(-1); β = 0.9-1.1 nC(-1)). A comparison of the characteristics of conical Ga2O3/EGaIn tips with the characteristics of other top-electrodes suggests that the EGaIn-based electrodes provide a particularly attractive technology for physical-organic studies of charge transport across SAMs.

  15. A nonsmooth nonlinear conjugate gradient method for interactive contact force problems

    Silcowitz, Morten; Abel, Sarah Maria Niebe; Erleben, Kenny

    2010-01-01

    of a nonlinear complementarity problem (NCP), which can be solved using an iterative splitting method, such as the projected Gauss–Seidel (PGS) method. We present a novel method for solving the NCP problem by applying a Fletcher–Reeves type nonlinear nonsmooth conjugate gradient (NNCG) type method. We analyze...... and present experimental convergence behavior and properties of the new method. Our results show that the NNCG method has at least the same convergence rate as PGS, and in many cases better....

  16. High efficiency algorithm for 3D transient thermo-elasto-plastic contact problem in reactor pressure vessel sealing system

    Xu Mingyu; Lin Tengjiao; Li Runfang; Du Xuesong; Li Shuian; Yang Yu

    2005-01-01

    There are some complex operating cases such as high temperature and high pressure during the operating process of nuclear reactor pressure vessel. It is necessary to carry out mechanical analysis and experimental investigation for its sealing ability. On the basis of the self-developed program for 3-D transient sealing analysis for nuclear reactor pressure vessel, some specific measures are presented to enhance the calculation efficiency in several aspects such as the non-linear solution of elasto-plastic problem, the mixed solution algorithm for contact problem as well as contract heat transfer problem and linear equation set solver. The 3-D transient sealing analysis program is amended and complemented, with which the sealing analysis result of the pressure vessel model can be obtained. The calculation results have good regularity and the calculation efficiency is twice more than before. (authors)

  17. On a free-surface problem with moving contact line: From variational principles to stable numerical approximations

    Fumagalli, Ivan; Parolini, Nicola; Verani, Marco

    2018-02-01

    We analyze a free-surface problem described by time-dependent Navier-Stokes equations. Surface tension, capillary effects and wall friction are taken into account in the evolution of the system, influencing the motion of the contact line - where the free surface hits the wall - and of the dynamics of the contact angle. The differential equations governing the phenomenon are first derived from the variational principle of minimum reduced dissipation, and then discretized by means of the ALE approach. The numerical properties of the resulting scheme are investigated, drawing a parallel with the physical properties holding at the continuous level. Some instability issues are addressed in detail, in the case of an explicit treatment of the geometry, and novel additional terms are introduced in the discrete formulation in order to damp the instabilities. Numerical tests assess the suitability of the approach, the influence of the parameters, and the effectiveness of the new stabilizing terms.

  18. Energy Consumption of Lactating Mothers: Current Situation and Problems

    Sandra Fikawati

    2014-08-01

    Full Text Available Recommendations on the adequacy of nutrient intake indicate that lactating mothers have higher nutritional needs than do pregnant mothers. High nutrient intake is necessary to help mothers recover after childbirth, produce milk, and maintain the quantity and quality of breast milk. It also prevents maternal malnutrition. Research has shown, however, that the dietary energy consumption of mothers during lactation was significantly lower than that during pregnancy. The current study explored the factors associated with decreased nutritional intake during maternal lactation. The study was conducted in March–April 2013, and the subjects were mothers with infants aged >6 months. Results revealed that the factors causing low dietary energy consumption among breastfeeding mothers were poor nutritional knowledge and attitude toward high energy intake requirements during lactation, lack of time to cook and eat because of infant care, reduced consumption of milk and supplements, dietary restrictions and prohibitions, and suboptimal advice from midwives/health personnel. Beginning from the antenatal care visit, health personnel should conduct effective counseling on the importance of nutrient intake during lactation. Advice should be provided not only to mothers, but also to their families to enable them to thoroughly support the mothers as they breastfeed their infants.

  19. Energy Security of Russia and the EU: Current Legal Problems

    Seliverstov, S.

    2009-07-01

    Security of energy supply is a cornerstone of European energy policy. It receives specific mention both in the Constitution Treaty and in the Lisbon Treaty. Of course, energy and energy-generated revenues are vital for Russia as well. It is a common understanding that Russia and the EU are extremely interdependent in terms of energy. On the one hand, Russia is the strategic energy supplier to the EU as a whole; for some member states Russian supplies represent the only source of the external energy flows. On the other hand, the revenues generated from the west-bound supplies of oil and gas constitute a significant share of the overall export income and of the budget of Russian Federation. Taking the interdependency as a point of departure the present article answers the following questions: What are the differences and the similarities in the European and the Russian approaches towards security of energy supply? Is their understanding of energy security so different? What are the current legal instruments guiding interaction in this sphere? What are the actual trends that could give some indication of how the situation may develop in the future? - While the concepts of 'security of energy supplies' or of 'energy security' are theoretical in nature, the ways the concepts are understood and the legal framework for them directly influences the way they are applied in practice. (author)

  20. Energy Security of Russia and the EU: Current Legal Problems

    Seliverstov, S.

    2009-01-01

    Security of energy supply is a cornerstone of European energy policy. It receives specific mention both in the Constitution Treaty and in the Lisbon Treaty. Of course, energy and energy-generated revenues are vital for Russia as well. It is a common understanding that Russia and the EU are extremely interdependent in terms of energy. On the one hand, Russia is the strategic energy supplier to the EU as a whole; for some member states Russian supplies represent the only source of the external energy flows. On the other hand, the revenues generated from the west-bound supplies of oil and gas constitute a significant share of the overall export income and of the budget of Russian Federation. Taking the interdependency as a point of departure the present article answers the following questions: What are the differences and the similarities in the European and the Russian approaches towards security of energy supply? Is their understanding of energy security so different? What are the current legal instruments guiding interaction in this sphere? What are the actual trends that could give some indication of how the situation may develop in the future? - While the concepts of 'security of energy supplies' or of 'energy security' are theoretical in nature, the ways the concepts are understood and the legal framework for them directly influences the way they are applied in practice. (author)

  1. Sleep medicine in Saudi Arabia: Current problems and future challenges

    BaHammam, Ahmed S.

    2011-01-01

    Sleep medicine is a relatively new specialty in the medical community. The practice of sleep medicine in Saudi Arabia (KSA) began in the mid to late nineties. Since its inception, the specialty has grown, and the number of specialists has increased. Nevertheless, sleep medicine is still underdeveloped in the KSA, particularly in the areas of clinical service, education, training and research. Based on available data, it appears that sleep disorders are prevalent among Saudis, and the demand for sleep medicine service is expected to rise significantly in the near future. A number of obstacles have been defined that hinder the progress of the specialty, including a lack of trained technicians, specialists and funding. Awareness about sleep disorders and their serious consequences is low among health care workers, health care authorities, insurance companies and the general public. A major challenge for the future is penetrating the educational system at all levels to demonstrate the high prevalence and serious consequences of sleep disorders. To attain adequate numbers of staff and facilities, the education and training of health care professionals at the level of sleep medicine specialists and sleep technologists is another important challenge that faces the specialty. This review discusses the current position of sleep medicine as a specialty in the KSA and the expected challenges of the future. In addition, it will guide clinicians interested in setting up new sleep medicine services in the KSA or other developing countries through the potential obstacles that may face them in this endeavor. PMID:21264164

  2. Sleep medicine in Saudi Arabia: Current problems and future challenges

    BaHammam Ahmed

    2011-01-01

    Full Text Available Sleep medicine is a relatively new specialty in the medical community. The practice of sleep medicine in Saudi Arabia (KSA began in the mid to late nineties. Since its inception, the specialty has grown, and the number of specialists has increased. Nevertheless, sleep medicine is still underdeveloped in the KSA, particularly in the areas of clinical service, education, training and research. Based on available data, it appears that sleep disorders are prevalent among Saudis, and the demand for sleep medicine service is expected to rise significantly in the near future. A number of obstacles have been defined that hinder the progress of the specialty, including a lack of trained technicians, specialists and funding. Awareness about sleep disorders and their serious consequences is low among health care workers, health care authorities, insurance companies and the general public. A major challenge for the future is penetrating the educational system at all levels to demonstrate the high prevalence and serious consequences of sleep disorders. To attain adequate numbers of staff and facilities, the education and training of health care professionals at the level of sleep medicine specialists and sleep technologists is another important challenge that faces the specialty. This review discusses the current position of sleep medicine as a specialty in the KSA and the expected challenges of the future. In addition, it will guide clinicians interested in setting up new sleep medicine services in the KSA or other developing countries through the potential obstacles that may face them in this endeavor.

  3. Non-contact current and voltage sensing method using a clamshell housing and a ferrite cylinder

    Carpenter, Gary D.; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C.; Schappert, Michael

    2016-04-26

    A method of measurement using a detachable current and voltage sensor provides an isolated and convenient technique for to measuring current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing that contains the current and voltage sensors, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, or alternative a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

  4. Aerial wildfire fighting: history, current situation, problems and perspectives

    A. V. Bryukhanov

    2017-10-01

    Full Text Available Nowadays aviation is among the most effective ways of early detection and suppression of wildfires. At the moment for the aerial wildfire fighting a few dozen models of aircraft are used worldwide, which are regularly modernized and renewed. In this article, authors give information about the history of fighting wildfires from the air, as well as analyze the current state of the issue with the use of aircraft and helicopter airtankers for firefighting, both at international level and in the territory of the Russian Federation. It is revealed that the most popular in the world still are the ground-based firefighting aircraft (regardless of the class of the carrying capacity. Amphibious firefighting aircraft now exist only in light (carrying capacity up to 5 tons and in medium type (capacity up to 15 tons. Among the helicopter aviation, heavy firefighting helicopters are mostly widely spread, as well as medium multipurpose helicopters, which are, apart from suppression, involved into delivery of people and goods to forest fire sites. The article is devoted to the main directions, according to which the development of aircraft tanker equipment abroad and in Russia occurs. The attention is directed to the most promising developments, and specific recommendations on how to increase the effectiveness of the fire aviation usage in Russia are given. Based on the studies carried out, a conclusion is drawn that for different countries there can be promising different types of firefighting aircraft, considering their landing field infrastructure, characteristics of forests and hydro systems, as well as the total area of the forest fund.

  5. Spin current induced by a charged tip in a quantum point contact

    Shchamkhalova, B.S., E-mail: s.bagun@gmail.com

    2017-03-15

    We show that the charged tip of the probe microscope, which is widely used in studying the electron transport in low-dimensional systems, induces a spin current. The effect is caused by the spin–orbit interaction arising due to an electric field produced by the charged tip. The tip acts as a spin-flip scatterer giving rise to the spin polarization of the net current and the occurrence of a spin density in the system.

  6. 3D Modeling and Testing of Contact Problems in Resistance Welding

    Nielsen, Chris Valentin

    A generic, electro-thermo-mechanically coupled finite element program is developed for three-dimensional simulation of resistance welding. The developed computer program has reached a level of a complete standalone software that can be utilized as a tool in the analysis of resistance welding...... of resistance welding processes, which cover a wide range of spot welding and projection welding applications. Three-dimensional simulation of spot welding enables the analysis of critical effects like electrode misalignment and shunt effects between consecutive spots. A single-sided spot welding case involving...... three-dimensional contact is also presented. This case was suggested by and discussed with a German steel manufacturer. When it comes to projection welding, a natural need for three-dimensional analysis arises in many cases because of the involved geometries. Cross-wire welding and welding of square...

  7. Current problems of VVER-1000 reactor core operation in Ukraine

    Bykov, A.

    2000-01-01

    Planned control rod drop time registration was passed two times a year per reactor unit. In 1992-1993 some control rods at almost all WWER-1000 units exceed the prescribed 4 second time limit. More than 7000 individual control rod time tests were made from the main correction measures. The following conclusions have been made from the current statistics data: (a) The main role of the vibration factor is proven in the fuel assembly (FA) bowing process. The greatest drop times and maximum of bowing values are concentrated at the vibration zone (2-4 FA rows from the reactor partition). The first FA row seems to be stable due to the interaction with the reactor partition; (b) Bowing relaxation will proceed during several fuel cycles (estimated value is 4-6), and depends on previous FA use history. It seems to be proven that previously bowed FAs effect the new FA, so previously bowed FAs are straightened until the middle of the fuel cycle. At some reactor units small drop time reduction is observed up to half of the fuel cycle from the start time values; (c) Control rod drop medium time (t) has almost linear dependence on operation time (τ) (t=k x τ + b]. Estimated by the method of least squares, values of k and b differ from unit to unit and from cycle to cycle. Values of k and b are in following ranges: b=2.0 - 2.6 seconds, k=5-50x10 -4 seconds per effective operation day; (d) Control rod drop time distribution changes through operation time. The position of maximum starts to shift after 240 effective days, and the form of the distribution start to change at the same time. Before 240 effective days, the distribution essentially does not change. To guarantee that the control rod system reliability is now within prescribed limits, we should continue testing. Additional analysis is needed. Test frequency can be reduced to avoid additional unreasonable transients. (authors)

  8. Geology and religion - historical perspective and current problems

    Kölbl-Ebert, Martina

    2010-05-01

    Today, when referring to the relationship between geology and religion, people usually at once think of Christian (and other) fundamentalists and their chronic palaeontological illiteracy leading to Creationism, to Intelligent Design, and a distrust of science in general among them most prominently geology, palaeontology and evolutionary biology. Thus the relationship of geology and religion is usually considered to be under strain. In former times things used to be quite different, and for most of human history the observation of geological phenomena and the acquisition of geological expertise was intimately connected with religious ideas. The Judeo-Christian sense of a finite Earth history prepared the ground for accepting the Earth's different strata as testimony to the development of our globe through time. It was this religious, theological framework, from which the early geology started to evolve. However, with increasing observations there was a growing mismatch between what was expected according to ancient, scriptural authorities and the actual data. The release of geology from religious connotations or associations was a development closely connected with the Enlightenment, when geology and religion started to drift apart not with a violent rupture but in a subtle and sometimes circuitous manner. However, outside the group of people with geological expertise, not all was smooth and peaceful, and some conservative clergymen as well as laypersons were rather shocked by the new ideas that came with geology: the immensity of the timescale, a dynamic Earth, not just a ruin shaped by the Deluge, and a dynamic biology too with the Darwinian theory of evolution, which was founded in part on palaeontological evidence and the assumption of a long geological time scale. Nevertheless and interestingly the Creationism we face today is a rather recent phenomenon influenced by a number of motives, most of them philosophical and theological in nature. And so, the current

  9. Direct current electric potential in an anisotropic half-space with vertical contact containing a conductive 3D body

    Li Ping

    2004-01-01

    Full Text Available Detailed studies of anomalous conductors in otherwise homogeneous media have been modelled. Vertical contacts form common geometries in galvanic studies when describing geological formations with different electrical conductivities on either side. However, previous studies of vertical discontinuities have been mainly concerned with isotropic environments. In this paper, we deal with the effect on the electric potentials, such as mise-à-la-masse anomalies, due to a conductor near a vertical contact between two anisotropic regions. We also demonstrate the interactive effects when the conductive body is placed across the vertical contact. This problem is normally very difficult to solve by the traditional numerical methods. The integral equations for the electric potential in anisotropic half-spaces are established. Green's function is obtained using the reflection and transmission image method in which five images are needed to fit the boundary conditions on the vertical interface and the air-earth surface. The effects of the anisotropy of the environments and the conductive body on the electric potential are illustrated with the aid of several numerical examples.

  10. Three-dimensional problems of the hydrodynamic interaction between bodies in a viscous fluid in the vicinity of their contact

    Petrov, A. G.; Kharlamov, Alexander A.

    2013-01-01

    Roč. 48, č. 5 (2013), s. 577-587 ISSN 0015-4628 R&D Projects: GA ČR(CZ) GA103/09/2066 Grant - others:Development of the Scientific Potential of the Higher Schoo(RU) 2.1.2/3604; Russian Foundation for Basic Research (RU) 11- 01-005355 Institutional support: RVO:67985874 Keywords : lubrication layer theory * viscous and inviscid fluids * thin layer * vicinity of a contact * three-dimensional problems Subject RIV: BK - Fluid Dynamics Impact factor: 0.320, year: 2013

  11. Current distribution effects in AC impedance spectroscopy of electroceramic point contact and thin film model electrodes

    Nielsen, Jimmi; Jacobsen, Torben

    2010-01-01

    the primary current distribution to the DC current distribution restricted to the Three-Phase-Boundary (TPB) zone introduces an error in the determination of the reaction resistance, Rreac = Z(freq. → 0) − Z(freq. → ∞). The error is estimated for different width of the effective TPB zone and a rule of thumb...... regarding its significance is provided. The associated characteristic impedance spectrum shape change is simulated and its origin discussed. Furthermore, the characteristic shape of impedance spectra of thin electroceramic film electrodes with lateral ohmic resistance is studied as a function...

  12. Automatic mesh refinement and local multigrid methods for contact problems: application to the Pellet-Cladding mechanical Interaction

    Liu, Hao

    2016-01-01

    This Ph.D. work takes place within the framework of studies on Pellet-Cladding mechanical Interaction (PCI) which occurs in the fuel rods of pressurized water reactor. This manuscript focuses on automatic mesh refinement to simulate more accurately this phenomena while maintaining acceptable computational time and memory space for industrial calculations. An automatic mesh refinement strategy based on the combination of the Local Defect Correction multigrid method (LDC) with the Zienkiewicz and Zhu a posteriori error estimator is proposed. The estimated error is used to detect the zones to be refined, where the local sub-grids of the LDC method are generated. Several stopping criteria are studied to end the refinement process when the solution is accurate enough or when the refinement does not improve the global solution accuracy anymore. Numerical results for elastic 2D test cases with pressure discontinuity show the efficiency of the proposed strategy. The automatic mesh refinement in case of unilateral contact problems is then considered. The strategy previously introduced can be easily adapted to the multi-body refinement by estimating solution error on each body separately. Post-processing is often necessary to ensure the conformity of the refined areas regarding the contact boundaries. A variety of numerical experiments with elastic contact (with or without friction, with or without an initial gap) confirms the efficiency and adaptability of the proposed strategy. (author) [fr

  13. Smooth dependence on data of solutions and contact regions for a Signorini problem

    Eisner, Jan; Kučera, Milan; Recke, L.

    2010-01-01

    Roč. 72, 3-4 (2010), s. 1358-1378 ISSN 0362-546X R&D Projects: GA AV ČR IAA100190506 Institutional research plan: CEZ:AV0Z10190503 Keywords : smooth dependence on date * Signorini problem * variational inequality Subject RIV: BA - General Mathematics Impact factor: 1.279, year: 2010 http://www.sciencedirect.com/science/article/pii/S0362546X09009808

  14. Modeling of the anode surface deformation in high-current vacuum arcs with AMF contacts

    Huang, Xiaolong; Wang, Lijun; Deng, Jie; Jia, Shenli; Qin, Kang; Shi, Zongqian

    2016-01-01

    A high-current vacuum arc subjected to an axial magnetic field is maintained in a diffuse status. With an increase in arc current, the energy carried by the arc column to the anode becomes larger and finally leads to the anode temperature exceeding the melting point of the anode material. When the anode melting pool is formed, and the rotational plasma of the arc column delivers its momentum to the melting pool, the anode melting pool starts to rotate and also flow outwards along the radial direction, which has been photographed by some researchers using high-speed cameras. In this paper, the anode temperature and melting status is calculated using the melting and solidification model. The swirl flow of the anode melting pool and deformation of the anode is calculated using the magneto-hydrodynamic (MHD) model with the volume of fraction (VOF) method. All the models are transient 2D axial-rotational symmetric models. The influence of the impaction force of the arc plasma, electromagnetic force, viscosity force, and surface tension of the liquid metal are all considered in the model. The heat flux density injected into the anode and the arc pressure are obtained from the 3D numerical simulation of the high-current vacuum arc using the MHD model, which gives more realistic parameters for the anode simulation. Simulation results show that the depth of the anode melting pool increases with an increase in the arc current. Some droplets sputter out from the anode surface, which is caused by the inertial centrifugal force of the rotational melting pool and strong plasma pressure. Compared with the previous anode melting model without consideration of anode deformation, when the deformation and swirl flow of the anode melting pool are considered, the anode temperature is relatively lower, and just a little more than the melting point of Cu. This is because of liquid droplets sputtering out of the anode surface taking much of the energy away from the anode surface. The

  15. Patch testing with markers of fragrance contact allergy. Do clinical tests correspond to patients' self-reported problems?

    Johansen, J D; Andersen, T F; Veien, N; Avnstorp, C; Andersen, K E; Menné, T

    1997-03-01

    The aim of the present study was to investigate the relationship between patients' own recognition of skin problems using consumer products and the results of patch testing with markers of fragrance sensitization. Eight hundred and eighty-four consecutive eczema patients, 18-69 years of age, filled in a questionnaire prior to patch testing with the European standard series. The questionnaire contained questions about skin symptoms from the use of scented and unscented products as well as skin reactions from contact with spices, flowers and citrus fruits that could indicate fragrance sensitivity. A highly significant association was found between reporting a history of visible skin symptoms from using scented products and a positive patch test to the fragrance mix, whereas no such relationship could be established to the Peru balsam in univariate or multivariate analysis. Our results suggest that the role of Peru balsam in detecting relevant fragrance contact allergy is limited, while most fragrance mix-positive patients are aware that the use of scented products may cause skin problems.

  16. A parallel finite element procedure for contact-impact problems using edge-based smooth triangular element and GPU

    Cai, Yong; Cui, Xiangyang; Li, Guangyao; Liu, Wenyang

    2018-04-01

    The edge-smooth finite element method (ES-FEM) can improve the computational accuracy of triangular shell elements and the mesh partition efficiency of complex models. In this paper, an approach is developed to perform explicit finite element simulations of contact-impact problems with a graphical processing unit (GPU) using a special edge-smooth triangular shell element based on ES-FEM. Of critical importance for this problem is achieving finer-grained parallelism to enable efficient data loading and to minimize communication between the device and host. Four kinds of parallel strategies are then developed to efficiently solve these ES-FEM based shell element formulas, and various optimization methods are adopted to ensure aligned memory access. Special focus is dedicated to developing an approach for the parallel construction of edge systems. A parallel hierarchy-territory contact-searching algorithm (HITA) and a parallel penalty function calculation method are embedded in this parallel explicit algorithm. Finally, the program flow is well designed, and a GPU-based simulation system is developed, using Nvidia's CUDA. Several numerical examples are presented to illustrate the high quality of the results obtained with the proposed methods. In addition, the GPU-based parallel computation is shown to significantly reduce the computing time.

  17. Current problems arising from the new law relating to franchise duties; Aktuelle Probleme des neuen Konzessionsabgabenrechts

    Becker, P.

    1996-12-31

    The contribution examines the advantages and drawbacks of the new ordinance in German law relating to payment of franchise duties. The ordinance may bring about new problems if abused as a means of bringing pressure to bear in negotiations for takeover of existing electric or gas supply systems by local governments. The author analyses the legitimation of such exploitation of the franchise duty and in this context the general legal framework. (orig./CB) [Deutsch] Der Beitrag untersucht Vor- und Nachteile der neuen Verordnung im Konzessionsabgabenrecht, die im Hinblick auf Auseinandersetzungen um die ``Ubernahme von Strom- oder Gasversorgungssystemen durch Gemeinden neue Probleme mit sich bringen koennte, wenn Konzessionsabgaben als Druckmittel eingesetzt werden. Der Autor analysiert die Zulaessigkeit eines derartigen Einsatzes und in diesem Zusammenhang auch die rechtliche Basis der Konzessionsabgaben. (orig./CB)

  18. Meshless Local Petrov-Galerkin Method for Solving Contact, Impact and Penetration Problems

    2006-11-30

    as the residual forces to the FEM domain, denoted as pFEM ≡ −pSGBEMu on SI in Fig. 2(c), re-solve the FEM problem and obtain the traction pSGBEMc on...crack surfaces SSGBEMc . 4. Repeat steps 2 and 3 until the residual load pFEM is small enough. 5. By adding the SGBEM solution to the FEM one, the...the given traction on St , we have pFEM = p and pSGBEM = 0 and get pOrg = pFEM + pSGBEM = p on St (21) ii) for the given displacement on Su, the SGBEM

  19. Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement

    Renstrom, P; Ljungqvist, A; Arendt, E

    2008-01-01

    clinicians and scientists to (1) review current evidence including data from the new Scandinavian ACL registries; (2) critically evaluate high-quality studies of injury mechanics; (3) consider the key elements of successful prevention programmes; (4) summarise clinical management including surgery...... and conservative management; and (5) identify areas for further research. Risk factors for female athletes suffering ACL injury include: (1) being in the preovulatory phase of the menstrual cycle compared with the postovulatory phase; (2) having decreased intercondylar notch width on plain radiography; and (3...

  20. Which doctors and with what problems contact a specialist service for doctors? A cross sectional investigation

    von der Tann Matthias

    2007-08-01

    Full Text Available Abstract Background In the United Kingdom, specialist treatment and intervention services for doctors are underdeveloped. The MedNet programme, created in 1997 and funded by the London Deanery, aims to fill this gap by providing a self-referral, face-to-face, psychotherapeutic assessment service for doctors in London and South-East England. MedNet was designed to be a low-threshold service, targeting doctors without formal psychiatric problems. The aim of this study was to delineate the characteristics of doctors utilising the service, to describe their psychological morbidity, and to determine if early intervention is achieved. Methods A cross-sectional study including all consecutive self-referred doctors (n = 121, 50% male presenting in 2002–2004 was conducted. Measures included standardised and bespoke questionnaires both self-report and clinician completed. The multi-dimensional evaluation included: demographics, CORE (CORE-OM, CORE-Workplace and CORE-A an instrument designed to evaluate the psychological difficulties of patients referred to outpatient services, Brief Symptom Inventory to quantify caseness and formal psychiatric illness, and Maslach Burnout Inventory. Results The most prevalent presenting problems included depression, anxiety, interpersonal, self-esteem and work-related issues. However, only 9% of the cohort were identified as severely distressed psychiatrically using this measure. In approximately 50% of the sample, problems first presented in the preceding year. About 25% were on sick leave at the time of consultation, while 50% took little or no leave in the prior 12 months. A total of 42% were considered to be at some risk of suicide, with more than 25% considered to have a moderate to severe risk. There were no significant gender differences in type of morbidity, severity or days off sick. Conclusion Doctors displayed high levels of distress as reflected in the significant proportion of those who were at some risk of

  1. 3D adaptive finite element method for a phase field model for the moving contact line problems

    Shi, Yi

    2013-08-01

    In this paper, we propose an adaptive finite element method for simulating the moving contact line problems in three dimensions. The model that we used is the coupled Cahn-Hilliard Navier-Stokes equations with the generalized Navier boundary condition(GNBC) proposed in [18]. In our algorithm, to improve the efficiency of the simulation, we use the residual type adaptive finite element algorithm. It is well known that the phase variable decays much faster away from the interface than the velocity variables. There- fore we use an adaptive strategy that will take into account of such difference. Numerical experiments show that our algorithm is both efficient and reliable. © 2013 American Institute of Mathematical Sciences.

  2. Patch testing with markers of fragrance contact allergy. Do clinical tests correspond to patients' self-reported problems?

    Johansen, J D; Andersen, T F; Veien, N

    1997-01-01

    The aim of the present study was to investigate the relationship between patients' own recognition of skin problems using consumer products and the results of patch testing with markers of fragrance sensitization. Eight hundred and eighty-four consecutive eczema patients, 18-69 years of age, filled...... in a questionnaire prior to patch testing with the European standard series. The questionnaire contained questions about skin symptoms from the use of scented and unscented products as well as skin reactions from contact with spices, flowers and citrus fruits that could indicate fragrance sensitivity. A highly...... significant association was found between reporting a history of visible skin symptoms from using scented products and a positive patch test to the fragrance mix, whereas no such relationship could be established to the Peru balsam in univariate or multivariate analysis. Our results suggest that the role...

  3. Bulk-Like Electrical Properties Induced by Contact-Limited Charge Transport in Organic Diodes: Revised Space Charge Limited Current

    Xu, Guangwei

    2018-02-22

    Charge transport governs the operation and performance of organic diodes. Illuminating the charge-transfer/transport processes across the interfaces and the bulk organic semiconductors is at the focus of intensive investigations. Traditionally, the charge transport properties of organic diodes are usually characterized by probing the current–voltage (I–V) curves of the devices. However, to unveil the landscape of the underlying potential/charge distribution, which essentially determines the I–V characteristics, still represents a major challenge. Here, the electrical potential distribution in planar organic diodes is investigated by using the scanning Kelvin probe force microscopy technique, a method that can clearly separate the contact and bulk regimes of charge transport. Interestingly, by applying to devices based on novel, high mobility organic materials, the space-charge-limited-current-like I–V curves, which are previously believed to be a result of the bulk transport, are surprisingly but unambiguously demonstrated to be caused by contact-limited conduction. A model accounting is developed for the transport properties of both the two metal/organic interfaces and the bulk. The results indicate that pure interface-dominated transport can indeed give rise to I–V curves similar to those caused by bulk transport. These findings provide a new insight into the charge injection and transport processes in organic diodes.

  4. Intermittent Contact Alternating Current Scanning Electrochemical Microscopy: A Method for Mapping Conductivities in Solid Li Ion Conducting Electrolyte Samples

    Catarelli, Samantha Raisa; Lonsdale, Daniel [Uniscan Instruments Ltd., Macclesfield (United Kingdom); Cheng, Lei [Energy Storage and Distribution Resources Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Materials Sciences and Engineering Department, University of California Berkeley, Berkeley, CA (United States); Syzdek, Jaroslaw [Bio-Logic USA LLC, Knoxville, TN (United States); Doeff, Marca, E-mail: mmdoeff@lbl.gov [Energy Storage and Distribution Resources Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2016-03-31

    Intermittent contact alternating current scanning electrochemical microscopy (ic-ac-SECM) has been used to determine the electrochemical response to an ac signal of several types of materials. A conductive gold foil and insulating Teflon sheet were first used to demonstrate that the intermittent contact function allows the topography and conductivity to be mapped simultaneously and independently in a single experiment. Then, a dense pellet of an electronically insulating but Li ion conducting garnet phase, Al-substituted Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} (LLZO), was characterized using the same technique. The polycrystalline pellet was prepared by classical ceramic sintering techniques and was comprised of large (~150 μm) grains. Critical information regarding the contributions of grain and grain boundary resistances to the total conductivity of the garnet phase was lacking due to ambiguities in the impedance data. In contrast, the use of the ic-ac-SECM technique allowed spatially resolved information regarding local conductivities to be measured directly. Impedance mapping of the pellet showed that the grain boundary resistance, while generally higher than that of grains, varied considerably, revealing the complex nature of the LLZO sample.

  5. Current-voltage characterization of Au contact on sol-gel ZnO films with and without conducting polymer

    Lin, Yow-Jon; Jheng, Mei-Jyuan; Zeng, Jian-Jhou

    2010-01-01

    This study investigates the current density-voltage (J-V) characteristics of Au/n-type ZnO and Au/polyaniline (PANI)/n-type ZnO devices. ZnO films were prepared by the sol-gel method. For Au/n-type ZnO devices, native defects and impurities resident within the ZnO depletion region contribute to barrier thinning of, carrier hopping across, and tunneling through the Schottky barrier. This leads to the formation of nonalloyed ohmic contacts. However, rectifying junctions were formed on n-type ZnO by employing the simple technique of spin-coating PANI to act as the electron-blocking layer. Our present results suggest that the ZnO depletion region at the PANI/n-type ZnO interface is not the origin of the rectifying behavior of Au/PANI/n-type ZnO contact. In addition, the presence of the built-in potential of Au/PANI/n-type ZnO devices could result in the shift of the J-V curve toward negative voltage. Excellent agreement between simulated and measured data was obtained when the built-in potential was taken into account in the J-V relationship.

  6. Theoretical investigation on current-voltage characteristics in all-carbon molecular device with different contact geometries

    Ye Fuqiu; Fan Zhiqiang; He Jun; Peng Jun; Tang Liming

    2012-01-01

    Applying nonequilibrium Green's functions in combination with the first-principles density-functional theory, we investigate electronic transport properties of an all-carbon molecular device consisting of one phenalenyl molecule and two zigzag graphene nanoribbons. The results show that the electronic transport properties are strongly dependent on the contact geometry and device's currents can drop obviously when the connect sites change from second-nearest sites from the central atom of the molecule (S site) to third-nearest sites from the central atom of the molecule (T site). More importantly, the negative differential resistance behavior is only observed on the negative bias region when the molecule connects the graphene nanoribbons through two T sites.

  7. The Case of Web-Based Course on Taxation: Current Status, Problems and Future Improvement

    Qin, Zhigang

    This paper mainly introduces the case of the web-based course on taxation developed by Xiamen University. We analyze the current status, problems and future improvement of the web-based course. The web-based course has the basic contents and modules, but it has several problems including unclear object, lacking interaction, lacking examination module, lacking study management module, and the learning materials and the navigation are too simple. According to its problems, we put forward the measures to improve it.

  8. Role of metal/silicon semiconductor contact engineering for enhanced output current in micro-sized microbial fuel cells

    Mink, Justine E.; Rojas, Jhonathan Prieto; Rader, Kelly; Hussain, Muhammad Mustafa

    2013-01-01

    contact material study. We utilized the industry standard contact material, aluminum, as well as a metal, whose silicide has recently been recognized for its improved performance in smallest scale integration requirements, cobalt. Our study shows

  9. An efficient scheme for a phase field model for the moving contact line problem with variable density and viscosity

    Gao, Min

    2014-09-01

    In this paper, we develop an efficient numerical method for the two phase moving contact line problem with variable density, viscosity, and slip length. The physical model is based on a phase field approach, which consists of a coupled system of the Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition [1,2,5]. To overcome the difficulties due to large density and viscosity ratio, the Navier-Stokes equations are solved by a splitting method based on a pressure Poisson equation [11], while the Cahn-Hilliard equation is solved by a convex splitting method. We show that the method is stable under certain conditions. The linearized schemes are easy to implement and introduce only mild CFL time constraint. Numerical tests are carried out to verify the accuracy, stability and efficiency of the schemes. The method allows us to simulate the interface problems with extremely small interface thickness. Three dimensional simulations are included to validate the efficiency of the method. © 2014 Elsevier Inc.

  10. An efficient scheme for a phase field model for the moving contact line problem with variable density and viscosity

    Gao, Min; Wang, Xiao-Ping

    2014-01-01

    In this paper, we develop an efficient numerical method for the two phase moving contact line problem with variable density, viscosity, and slip length. The physical model is based on a phase field approach, which consists of a coupled system of the Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition [1,2,5]. To overcome the difficulties due to large density and viscosity ratio, the Navier-Stokes equations are solved by a splitting method based on a pressure Poisson equation [11], while the Cahn-Hilliard equation is solved by a convex splitting method. We show that the method is stable under certain conditions. The linearized schemes are easy to implement and introduce only mild CFL time constraint. Numerical tests are carried out to verify the accuracy, stability and efficiency of the schemes. The method allows us to simulate the interface problems with extremely small interface thickness. Three dimensional simulations are included to validate the efficiency of the method. © 2014 Elsevier Inc.

  11. Solution of 3D inverse scattering problems by combined inverse equivalent current and finite element methods

    Kılıç, Emre; Eibert, Thomas F.

    2015-01-01

    An approach combining boundary integral and finite element methods is introduced for the solution of three-dimensional inverse electromagnetic medium scattering problems. Based on the equivalence principle, unknown equivalent electric and magnetic surface current densities on a closed surface are utilized to decompose the inverse medium problem into two parts: a linear radiation problem and a nonlinear cavity problem. The first problem is formulated by a boundary integral equation, the computational burden of which is reduced by employing the multilevel fast multipole method (MLFMM). Reconstructed Cauchy data on the surface allows the utilization of the Lorentz reciprocity and the Poynting's theorems. Exploiting these theorems, the noise level and an initial guess are estimated for the cavity problem. Moreover, it is possible to determine whether the material is lossy or not. In the second problem, the estimated surface currents form inhomogeneous boundary conditions of the cavity problem. The cavity problem is formulated by the finite element technique and solved iteratively by the Gauss–Newton method to reconstruct the properties of the object. Regularization for both the first and the second problems is achieved by a Krylov subspace method. The proposed method is tested against both synthetic and experimental data and promising reconstruction results are obtained

  12. Solution of 3D inverse scattering problems by combined inverse equivalent current and finite element methods

    Kılıç, Emre, E-mail: emre.kilic@tum.de; Eibert, Thomas F.

    2015-05-01

    An approach combining boundary integral and finite element methods is introduced for the solution of three-dimensional inverse electromagnetic medium scattering problems. Based on the equivalence principle, unknown equivalent electric and magnetic surface current densities on a closed surface are utilized to decompose the inverse medium problem into two parts: a linear radiation problem and a nonlinear cavity problem. The first problem is formulated by a boundary integral equation, the computational burden of which is reduced by employing the multilevel fast multipole method (MLFMM). Reconstructed Cauchy data on the surface allows the utilization of the Lorentz reciprocity and the Poynting's theorems. Exploiting these theorems, the noise level and an initial guess are estimated for the cavity problem. Moreover, it is possible to determine whether the material is lossy or not. In the second problem, the estimated surface currents form inhomogeneous boundary conditions of the cavity problem. The cavity problem is formulated by the finite element technique and solved iteratively by the Gauss–Newton method to reconstruct the properties of the object. Regularization for both the first and the second problems is achieved by a Krylov subspace method. The proposed method is tested against both synthetic and experimental data and promising reconstruction results are obtained.

  13. Current Problems of Trade Union-Party Relations in Switzerland: Reorientation Versus Inertia

    Siegenthaler, Jurg K.

    1975-01-01

    The postwar realignment of union-party relations in Switzerland severed old formal ties but left some important links undisturbed; practical and effective cooperation on legislative items supports current informal union-party alliances. Major current problems include the unions' demand for codetermination in industry and the huge numbers of…

  14. Role of metal/silicon semiconductor contact engineering for enhanced output current in micro-sized microbial fuel cells

    Mink, Justine E.

    2013-11-25

    We show that contact engineering plays an important role to extract the maximum performance from energy harvesters like microbial fuel cells (MFCs). We experimented with Schottky and Ohmic methods of fabricating contact areas on silicon in an MFC contact material study. We utilized the industry standard contact material, aluminum, as well as a metal, whose silicide has recently been recognized for its improved performance in smallest scale integration requirements, cobalt. Our study shows that improvements in contact engineering are not only important for device engineering but also for microsystems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Contact problem for a solid indenter and a viscoelastic half-space described by the spectrum of relaxation and retardation times

    Stepanov, F. I.

    2018-04-01

    The mechanical properties of a material which is modeled by an exponential creep kernel characterized by a spectrum of relaxation and retardation times are studied. The research is carried out considering a contact problem for a solid indenter sliding over a viscoelastic half-space. The contact pressure, indentation depth of the indenter, and the deformation component of the friction coefficient are analyzed with respect to the case of half-space material modeled by single relaxation and retardation times.

  16. EDDYMULT: a computing system for solving eddy current problems in a multi-torus system

    Nakamura, Yukiharu; Ozeki, Takahisa

    1989-03-01

    A new computing system EDDYMULT based on the finite element circuit method has been developed to solve actual eddy current problems in a multi-torus system, which consists of many torus-conductors and various kinds of axisymmetric poloidal field coils. The EDDYMULT computing system can deal three-dimensionally with the modal decomposition of eddy current in a multi-torus system, the transient phenomena of eddy current distributions and the resultant magnetic field. Therefore, users can apply the computing system to the solution of the eddy current problems in a tokamak fusion device, such as the design of poloidal field coil power supplies, the mechanical stress design of the intensive electromagnetic loading on device components and the control analysis of plasma position. The present report gives a detailed description of the EDDYMULT system as an user's manual: 1) theory, 2) structure of the code system, 3) input description, 4) problem restrictions, 5) description of the subroutines, etc. (author)

  17. Turkey’s Current Account Deficit Problem and Its Effects on the European Union Accession

    Osman Zekayi Orhan

    2014-06-01

    Full Text Available In developing countries, long-term current account deficits may cause serious problems in the economy. Turkey's current account deficit and the financing of this deficit is one of the most widely debated issues in recent years. There are two different views about the emergence of the current account deficit. According to the first view, the current account deficit is due to the increase in demand created by economic growth after the 2001 crisis. According to the other opinion, this deficit is a result of an overvalued domestic currency, which is created by high interest rates accelerating the flow of short-term speculative capital. Since the current account deficit is financed with debt, the increasing external debt of the country is threatening the future of the economy. In this study, firstly the current account deficit problem in Turkey and the factors affecting the current operations which play an important role in financing the short-term capital movements are explained. Secondly, the policies to ensure the current account balance are defined. Finally the effects of the current account deficit problem on the European Union accession is discussed.

  18. A non-Hertzian method for solving wheel-rail normal contact problem taking into account the effect of yaw

    Liu, Binbin; Bruni, Stefano; Vollebregt, Edwin

    2016-09-01

    A novel approach is proposed in this paper to deal with non-Hertzian normal contact in wheel-rail interface, extending the widely used Kik-Piotrowski method. The new approach is able to consider the effect of the yaw angle of the wheelset against the rail on the shape of the contact patch and on pressure distribution. Furthermore, the method considers the variation of profile curvature across the contact patch, enhancing the correspondence to CONTACT for highly non-Hertzian contact conditions. The simulation results show that the proposed method can provide more accurate estimation than the original algorithm compared to Kalker's CONTACT, and that the influence of yaw on the contact results is significant under certain circumstances.

  19. Current-voltage characteristics of quantum-point contacts in the closed-channel regime: Transforming the bias voltage into an energy scale

    Gloos, K.; Utko, P.; Aagesen, M.

    2006-01-01

    We investigate the I(V) characteristics (current versus bias voltage) of side-gated quantum-point contacts, defined in GaAs/AlxGa1-xAs heterostructures. These point contacts are operated in the closed-channel regime, that is, at fixed gate voltages below zero-bias pinch-off for conductance. Our....... Such a built-in energy-voltage calibration allows us to distinguish between the different contributions to the electron transport across the pinched-off contact due to thermal activation or quantum tunneling. The first involves the height of the barrier, and the latter also its length. In the model that we...

  20. Eddy current imaging. Simplifying the direct problem. Analysis of a 2D case with formulations

    Spineanu, A.; Zorgati, R.

    1995-01-01

    Eddy current non-destructive testing is used by EDF to detect faults affecting conductive objects such as steam generator tubes. A new technique, known as eddy current imaging, is being developed to facilitate diagnosis in this context. The first stage in this work, discussed in the present paper, consists in solving the direct problem. This entails determining the measurable quantities, on the basis of a thorough knowledge of the material considered. This was done by formulating the direct problem in terms of eddy currents in general 3D geometry context, applying distribution theory and Maxwell equations. Since no direct problem code was available we resorted to simplified situations. Taking care not to interfere with previous developments or those to be attempted in an inversion context, we studied the case of a flaw affecting a 2D structure, illuminated by a plane wave type probe. For this configuration, we studied the exact model and compared results with those of a linearized simplified model. This study emphasizes the ill-posed situation of the eddy current inverse problem related with the severe electromagnetic field attenuation. This means that regularization of the inverse problem, although absolutely necessary, will not be sufficient. Owing to the simplicity of the models available and implemented during the inversion process, processing real data would not yet be possible. We must first focus all our efforts on the direct 3 D problem, in conformity with the requirements of the inverse procedure ad describing a realistic eddy current NDT situation. At the same time, consideration should be given to the design of a specific probe customized for eddy current imaging. (authors). 9 refs., 5 figs., 3 appends

  1. Taxonomic Review of Classical and Current Literature on the Perennial American Family Forest Problem

    Thomas J. Straka

    2011-08-01

    Full Text Available One of the fundamental issues in American forest policy has been the small forest ownership problem. Early in the twentieth century, it was called the farm forestry problem, later, the nonindustrial private forest problem, and today, the family forest problem. Family forest owners are thought to manage their lands in a suboptimal manner resulting in low forest productivity relative to other ownership groups. This can lead to future timber supply problems. The exact nature of the problem, especially its social and economic basis, was a common subject of early forestry research studies. This article includes many of the major nonindustrial private forest or family forest studies, from early to current, and classifies them both by themes used by other authors and categories that relate to major research areas in the current literature. A major focus of this literature deals with promoting management on family forest holdings and possible land management incentives and disincentives. Natural trends in family forest ownership, like parcelization, also impact upon forest management opportunities. By developing a taxonomy that classifies these studies by research objective, methodology, owner motivation, and problem definition, this article serves to organize the family forest literature in a manner that provides a temporal framework for better understanding the historical motivation for and development of family forest research in the United States.

  2. Solution of magnetic field and eddy current problem induced by rotating magnetic poles (abstract)

    Liu, Z. J.; Low, T. S.

    1996-04-01

    The magnetic field and eddy current problems induced by rotating permanent magnet poles occur in electromagnetic dampers, magnetic couplings, and many other devices. Whereas numerical techniques, for example, finite element methods can be exploited to study various features of these problems, such as heat generation and drag torque development, etc., the analytical solution is always of interest to the designers since it helps them to gain the insight into the interdependence of the parameters involved and provides an efficient tool for designing. Some of the previous work showed that the solution of the eddy current problem due to the linearly moving magnet poles can give satisfactory approximation for the eddy current problem due to rotating fields. However, in many practical cases, especially when the number of magnet poles is small, there is significant effect of flux focusing due to the geometry. The above approximation can therefore lead to marked errors in the theoretical predictions of the device performance. Bernot et al. recently described an analytical solution in a polar coordinate system where the radial field is excited by a time-varying source. A discussion of an analytical solution of the magnetic field and eddy current problems induced by moving magnet poles in radial field machines will be given in this article. The theoretical predictions obtained from this method is compared with the results obtained from finite element calculations. The validity of the method is also checked by the comparison of the theoretical predictions and the measurements from a test machine. It is shown that the introduced solution leads to a significant improvement in the air gap field prediction as compared with the results obtained from the analytical solution that models the eddy current problems induced by linearly moving magnet poles.

  3. Thermal contact resistance measurement of conduction cooled binary current lead joint block in cryocooler based self field I-V characterization facility

    Kundu, Ananya, E-mail: ananya@ipr.res.in; Das, Subrat Kumar; Agarwal, Anees Bano Pooja; Pradhan, Subrata [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2016-05-23

    In the present study thermal resistance of conduction cooled current lead joint block employing two different interfacial material namely AlN sheet and Kapton Film have been studied in the temperature range 5K-35K. In each case, the performance of different interlayer materials e.g. Indium foil for moderately pressurized contacts (contact pressure <1 MPa), and Apiezon N Grease, GE varnish for low pressurized contact (contact pressure <1 MPa) is studied. The performances of AlN joint with Indium foil and with Apeizon N Grease are studied and it is observed that the contact resistance reduces more with indium foil as compared to greased contact. The contact resistance measurements of Kapton film with Apiezon N grease and with GE varnish were also carried out in the same temperature range. A comparative study of AlN joint with Indium foil and Kapton with GE varnish as filler material is carried out to demonstrate better candidate material among Kapton and AlN for a particular filler material in the same temperature range.

  4. Use of the internet in international emergency management: current problems and possible improvements

    Palsson, S.E.

    2003-01-01

    Full text: The Internet has during the last decade grown rapidly to become one of the main tools for exchanging information in a modern society. This has been in parallel with similar growth in communication technology, providing both wired and wireless high capacity communication channels. Many special applications and services have been developed making use of the new technology. International emergency management is however currently only making use of a part of the possibilities the internet can offer. This is due to lack of co-operation, harmonization and not using recent standards for information exchange. This problem can be solved simply by more co-operation and active use of modern standards. The problem for international emergency management arises from the wide variety of users and their needs. On one hand there are users in countries with nuclear power plants and sophisticated decision support systems, on the other hand there are countries without nuclear reactors within or near their boarders. The latter may not be able to justify developing or setting up complex decision support systems, but in most cases they would want to be able to make use of internationally distributed information in some efficient way. Many of the sophisticated web based applications have been excellently tailored for the needs of the owners, but are often less suitable for others. Some of the typical problems are: too large files, integration of content and layout information in one file, device and web browser specific solutions, inconsistent structure. The HTML language traditionally used for web pages has tags to identify different types of information. But modern HTML web pages are generally loaded with nonstandard device specific formatting instructions. Having two web pages that look the same does not mean that the underlying code is the same. The author conducted a test a couple of years ago where commercial software was used to transform web pages from a few emergency

  5. Fractal-Based Methods and Inverse Problems for Differential Equations: Current State of the Art

    Herb E. Kunze

    2014-01-01

    Full Text Available We illustrate, in this short survey, the current state of the art of fractal-based techniques and their application to the solution of inverse problems for ordinary and partial differential equations. We review several methods based on the Collage Theorem and its extensions. We also discuss two innovative applications: the first one is related to a vibrating string model while the second one considers a collage-based approach for solving inverse problems for partial differential equations on a perforated domain.

  6. Contact problem on indentation of an elastic half-plane with an inhomogeneous coating by a flat punch in the presence of tangential stresses on a surface

    Volkov, Sergei S.; Vasiliev, Andrey S.; Aizikovich, Sergei M.; Sadyrin, Evgeniy V.

    2018-05-01

    Indentation of an elastic half-space with functionally graded coating by a rigid flat punch is studied. The half-plane is additionally subjected to distributed tangential stresses. Tangential stresses are represented in a form of Fourier series. The problem is reduced to the solution of two dual integral equations over even and odd functions describing distribution of unknown normal contact stresses. The solutions of these dual integral equations are constructed by the bilateral asymptotic method. Approximated analytical expressions for contact normal stresses are provided.

  7. Current-voltage curves of atomic-sized transition metal contacts: An explanation of why Au is ohmic and Pt is not

    Nielsen, S.K.; Brandbyge, Mads; Hansen, K.

    2002-01-01

    We present an experimental study of current-voltage (I-V) curves on atomic-sized Au and Pt contacts formed under cryogenic vacuum (4.2 K). Whereas I-V curves for Au are almost Ohmic, the conductance G=I/V for Pt decreases with increasing voltage, resulting in distinct nonlinear I-V behavior...

  8. Crack problem in superconducting cylinder with exponential distribution of critical-current density

    Zhao, Yufeng; Xu, Chi; Shi, Liang

    2018-04-01

    The general problem of a center crack in a long cylindrical superconductor with inhomogeneous critical-current distribution is studied based on the extended Bean model for zero-field cooling (ZFC) and field cooling (FC) magnetization processes, in which the inhomogeneous parameter η is introduced for characterizing the critical-current density distribution in inhomogeneous superconductor. The effect of the inhomogeneous parameter η on both the magnetic field distribution and the variations of the normalized stress intensity factors is also obtained based on the plane strain approach and J-integral theory. The numerical results indicate that the exponential distribution of critical-current density will lead a larger trapped field inside the inhomogeneous superconductor and cause the center of the cylinder to fracture more easily. In addition, it is worth pointing out that the nonlinear field distribution is unique to the Bean model by comparing the curve shapes of the magnetization loop with homogeneous and inhomogeneous critical-current distribution.

  9. Investigation of protection problems due to geomagnetically induced currents (solar magnetic disturbances, transformers)

    1997-01-01

    The problems with geomagnetically induced currents (GIC) flowing in power systems during solar magnetic disturbances were studied. Transformers can overheat as a result of GIC because they can cause offset saturation of power system transformers. Harmonic currents can also be introduced into the system which then affect the relay and protection systems. Several studies have been conducted using simplified transformer core models to predict the transformer response to DC excitation. In this study, an accurate transformer core model was developed and validated by comparing the recorded waveforms during GIC events with simulated waveforms using the model. The new transformer core model was used to evaluate the performance of different protection schemes under GIC

  10. Analysis of critical thinking ability in direct current electrical problems solving

    Hartono; Sunarno, Widha; Sarwanto; Arya Nugraha, Dewanta

    2017-11-01

    This study concern on analyzing the ability of students in critical thinking skills on the subject matter of direct current electricity. Samples were taken using purposive random sampling consisted of 32 students of grade XI, Multimedia 1, SMK Negeri 3 Surakarta in academic year 2016/2017. This study used descriptive quantitative method. The data were collected using tests and interviews regarding the subject matter of direct current electricity. Based on the results, students are getting some difficulties in solving problem in indicator 4. The average of students’ correct answer is 62.8%.

  11. Shoe allergic contact dermatitis.

    Matthys, Erin; Zahir, Amir; Ehrlich, Alison

    2014-01-01

    Foot dermatitis is a widespread condition, affecting men and women of all ages. Because of the location, this condition may present as a debilitating problem to those who have it. Allergic contact dermatitis involving the feet is frequently due to shoes or socks. The allergens that cause shoe dermatitis can be found in any constituent of footwear, including rubber, adhesives, leather, dyes, metals, and medicaments. The goal of treatment is to identify and minimize contact with the offending allergen(s). The lack of product information released from shoe manufacturers and the continually changing trends in footwear present a challenge in treating this condition. The aim of this study is to review the current literature on allergic contact shoe dermatitis; clinical presentation, allergens, patch testing, and management will be discussed. PubMed and MEDLINE databases were used for the search, with a focus on literature updates from the last 15 years.

  12. Applications of integral equation methods for the numerical solution of magnetostatic and eddy current problems

    Trowbridge, C.W.

    1976-06-01

    Various integral equation methods are described. For magnetostatic problems three formulations are considered in detail, (a) the direct solution method for the magnetisation distribution in permeable materials, (b) a method based on a scalar potential and (c) the use of an integral equation derived from Green's Theorem, i.e. the so-called Boundary Integral Method (BIM). In the case of (a) results are given for two-and three-dimensional non-linear problems with comparisons against measurement. For methods (b) and (c) which both lead to a more economic use of the computer than (a) some preliminary results are given for simple cases. For eddy current problems various methods are discussed and some results are given from a computer program based on a vector potential formulation. (author)

  13. Applications of integral equation methods for the numerical solution of magnetostatic and eddy current problems

    Trowbridge, C W

    1976-06-01

    Various integral equation methods are described. For magnetostatic problems three formulations are considered in detail, (a) the direct solution method for the magnetisation distribution in permeable materials, (b) a method based on a scalar potential, and (c) the use of an integral equation derived from Green's Theorem, i.e. the so-called Boundary Integral Method (BIM). In the case of (a) results are given for two-and three-dimensional non-linear problems with comparisons against measurement. For methods (b) and (c), which both lead to a more economical use of the computer than (a), some preliminary results are given for simple cases. For eddy current problems various methods are discussed and some results are given from a computer program based on a vector potential formulation.

  14. A Survey on Renewable Energy Development in Malaysia: Current Status, Problems and Prospects

    Alam Syed Shah; Nor Nor Fariza Mohd; Ahmad Maisarah; Hashim Nik Hazrul Nik

    2016-01-01

    Energy demand in Malaysia is increasing over seven per cent a year, while forty per cent of the energy is supplied from conventional fossil fuel. However, a number of social barriers have mired the social acceptance of renewable energy among the users. This study investigates the current status of renewable energy, problems and future outlook of renewable energy in Malaysia. A total of 200 respondents were surveyed from Klang Valley in Malaysia. Majority of the respondents use energy to gener...

  15. Two numerical methods for the solution of two-dimensional eddy current problems

    Biddlecombe, C.S.

    1978-07-01

    A general method for the solution of eddy current problems in two dimensions - one component of current density and two of magnetic field, is reported. After examining analytical methods two numerical methods are presented. Both solve the two dimensional, low frequency limit of Maxwell's equations for transient eddy currents in conducting material, which may be permeable, in the presence of other non-conducting permeable material. Both solutions are expressed in terms of the magnetic vector potential. The first is an integral equation method, using zero order elements in the discretisation of the unknown source regions. The other is a differential equation method, using a first order finite element mesh, and the Galerkin weighted residual procedure. The resulting equations are solved as initial-value problems. Results from programs based on each method are presented showing the power and limitations of the methods and the range of problems solvable. The methods are compared and recommendations are made for choosing between them. Suggestions are made for improving both methods, involving boundary integral techniques. (author)

  16. Point-contact spectroscopy of unsaturated transition-metal oxides and the problem of zero-bias anomalies

    Tulina, N.A.

    1985-01-01

    The point-contact spectra of oxides with metallic conductivity WO 2 , ReO 3 , and MoO 2 are studied. It is shown that the zero-bias anomalies, which are often observed in the spectra of transition metals, are determined by the presence of an interlayer consisting of an oxide of the above type in the region of the point contact. Zero-bias anomalies do not occur in the point-contact spectra of Zn--MoO 2 -chip heterocontacts. In the studies of such heterocontacts the major maxima in the electron--phonon interaction of MoO 2 were determined at the energies hω/sub T/Aapprox.28 meV and hω/sub L/Aapprox.41 meV

  17. On the Inverse EEG Problem for a 1D Current Distribution

    George Dassios

    2014-01-01

    Full Text Available Albanese and Monk (2006 have shown that, it is impossible to recover the support of a three-dimensional current distribution within a conducting medium from the knowledge of the electric potential outside the conductor. On the other hand, it is possible to obtain the support of a current which lives in a subspace of dimension lower than three. In the present work, we actually demonstrate this possibility by assuming a one-dimensional current distribution supported on a small line segment having arbitrary location and orientation within a uniform spherical conductor. The immediate representation of this problem refers to the inverse problem of electroencephalography (EEG with a linear current distribution and the spherical model of the brain-head system. It is shown that the support is identified through the solution of a nonlinear algebraic system which is investigated thoroughly. Numerical tests show that this system has exactly one real solution. Exact solutions are analytically obtained for a couple of special cases.

  18. Current suicidal ideation in treatment-seeking individuals in the United Kingdom with gambling problems.

    Ronzitti, Silvia; Soldini, Emiliano; Smith, Neil; Potenza, Marc N; Clerici, Massimo; Bowden-Jones, Henrietta

    2017-11-01

    Studies show higher lifetime prevalence of suicidality in individuals with pathological gambling. However, less is known about the relationship between pathological gambling and current suicidal ideation. We investigated socio-demographic, clinical and gambling-related variables associated with suicidality in treatment-seeking individuals. Bivariate analyses and logistic regression models were generated on data from 903 individuals to identify measures associated with aspects of suicidality. Forty-six percent of patients reported current suicidal ideation. People with current suicidal thoughts were more likely to report greater problem-gambling severity (psuicidality. Logistic regression models suggested that past suicidal ideation (psuicidality. Our findings suggest that the severity of anxiety disorder, along with a lifetime history of suicidal ideation, may help to identify treatment-seeking individuals with pathological gambling with a higher risk of suicidality, highlighting the importance of assessing suicidal ideation in clinical settings. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Quasistatic normal-compliance contact problem of visco-elastic bodies with Coulomb friction implemented by QP and SGBEM

    Vodička, R.; Mantič, V.; Roubíček, Tomáš

    2017-01-01

    Roč. 315, May (2017), s. 249-272 ISSN 0377-0427 Institutional support: RVO:61388998 Keywords : contact mechanics * evolution variational inequalities * numerical approximation Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.357, year: 2016 http://www.sciencedirect.com/science/article/pii/S037704271630499X

  20. Patch testing with markers of fragrance contact allergy. Do clinical tests correspond to patients' self-reported problems?

    Johansen, J D; Andersen, T F; Veien, N

    1997-01-01

    in a questionnaire prior to patch testing with the European standard series. The questionnaire contained questions about skin symptoms from the use of scented and unscented products as well as skin reactions from contact with spices, flowers and citrus fruits that could indicate fragrance sensitivity. A highly...

  1. On the solutions of a dynamic contact problem for a thermoelastic von Kármán plate

    Bock, I.; Jarušek, Jiří; Šilhavý, Miroslav

    2016-01-01

    Roč. 32, December (2016), s. 111-135 ISSN 1468-1218 R&D Projects: GA ČR(CZ) GAP201/12/0671 Institutional support: RVO:67985840 Keywords : thermoelastic plate * unilateral dynamic contact * rigid obstacle Subject RIV: BA - General Mathematics Impact factor: 1.659, year: 2016 http://www.sciencedirect.com/science/article/pii/S146812181630013X

  2. The general practitioner as the first contacted health professional by patients with psychosocial problems: a European study.

    Boerma, W.G.W.; Verhaak, P.F.M.

    1999-01-01

    Background: there are considerable differences between and within countries in the involvement of general practitioners (GPs) in psychosocial care. This study aimed to describe the self-perceived role of GPs in 30 European countries as the first contacted professional for patients with psychosocial

  3. A finite element method for the numerical solution of the coupled Cahn-Hilliard and Navier-Stokes system for moving contact line problems

    Bao, Kai

    2012-10-01

    In this paper, a semi-implicit finite element method is presented for the coupled Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition for the moving contact line problems. In our method, the system is solved in a decoupled way. For the Cahn-Hilliard equations, a convex splitting scheme is used along with a P1-P1 finite element discretization. The scheme is unconditionally stable. A linearized semi-implicit P2-P0 mixed finite element method is employed to solve the Navier-Stokes equations. With our method, the generalized Navier boundary condition is extended to handle the moving contact line problems with complex boundary in a very natural way. The efficiency and capacity of the present method are well demonstrated with several numerical examples. © 2012 Elsevier Inc..

  4. A finite element method for the numerical solution of the coupled Cahn-Hilliard and Navier-Stokes system for moving contact line problems

    Bao, Kai; Shi, Yi; Sun, Shuyu; Wang, Xiaoping

    2012-01-01

    In this paper, a semi-implicit finite element method is presented for the coupled Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition for the moving contact line problems. In our method, the system is solved in a decoupled way. For the Cahn-Hilliard equations, a convex splitting scheme is used along with a P1-P1 finite element discretization. The scheme is unconditionally stable. A linearized semi-implicit P2-P0 mixed finite element method is employed to solve the Navier-Stokes equations. With our method, the generalized Navier boundary condition is extended to handle the moving contact line problems with complex boundary in a very natural way. The efficiency and capacity of the present method are well demonstrated with several numerical examples. © 2012 Elsevier Inc..

  5. Prevalence, putative mechanisms, and current management of sleep problems during chemotherapy for cancer

    Palesh O

    2012-12-01

    Full Text Available Oxana Palesh,1 Luke Peppone,2 Pasquale F Innominato,3–5 Michelle Janelsins,2 Monica Jeong,1 Lisa Sprod,7 Josee Savard,6 Max Rotatori,1 Shelli Kesler,1 Melinda Telli,1 Karen Mustian21Stanford University School of Medicine, Stanford, CA, USA; 2University of Rochester School of Medicine and Dentistry, Rochester, NY, USA; 3INSERM, UMRS 776, Biological Rhythms and Cancers, Villejuif, France; 4Faculty of Medicine, Universite Paris Sud, le Kremlin-Bicêtre, France; 5APHP, Chronotherapy Unit, Department of Oncology, Paul Brousse Hospital, Villejuif, France; 6Laval University, Quebec, Canada; 7University of North Carolina, Wilmington, NC, USAAbstract: Sleep problems are highly prevalent in cancer patients undergoing chemotherapy. This article reviews existing evidence on etiology, associated symptoms, and management of sleep problems associated with chemotherapy treatment during cancer. It also discusses limitations and methodological issues of current research. The existing literature suggests that subjectively and objectively measured sleep problems are the highest during the chemotherapy phase of cancer treatments. A possibly involved mechanism reviewed here includes the rise in the circulating proinflammatory cytokines and the associated disruption in circadian rhythm in the development and maintenance of sleep dysregulation in cancer patients during chemotherapy. Various approaches to the management of sleep problems during chemotherapy are discussed with behavioral intervention showing promise. Exercise, including yoga, also appear to be effective and safe at least for subclinical levels of sleep problems in cancer patients. Numerous challenges are associated with conducting research on sleep in cancer patients during chemotherapy treatments and they are discussed in this review. Dedicated intervention trials, methodologically sound and sufficiently powered, are needed to test current and novel treatments of sleep problems in cancer patients

  6. Indentation of an Elastic Half-space by a Rigid Flat Punch as a Model Problem for Analysing Contact Problems with Coulomb Friction

    Ballard, P.; Jarušek, Jiří

    2011-01-01

    Roč. 103, č. 1 (2011), s. 15-52 ISSN 0374-3535 R&D Projects: GA AV ČR IAA100750802 Institutional research plan: CEZ:AV0Z10190503 Keywords : elasticity * contact * friction * uniqueness * singularity Subject RIV: BA - General Mathematics Impact factor: 1.110, year: 2011 http://link.springer.com/article/10.1007%2Fs10659-010-9270-9

  7. [The current problems and cross-cultural perspectives of patient-doctor relation: an overview].

    Koch, Eckhardt; Turgut, Tolga

    2004-01-01

    The success of the treatment in medicine, especially in psychiatry is based on the form and the strength of the patient-doctor relation. This complex and dynamic relation is changing in accordance with the social and technological development of the society. The context of the patient-doctor relation is determined by the present day culture as well as the traditional background. An overview of current patient-doctor relation and of problems that physicians and in particular psychiatrists meet is presented. Physicians have responsibilities in building patient-doctor relation. The ethical and legal aspects of these responsibilities are presented. The former paternalistic type of patient-doctor relation is evolving into a more equal and democratic relation. New problems are being encountered continuously in the changing process. Beside the of the process itself, the effects of progress in medical technology and communication systems on patient-doctor relation and the pressure, put from the insurance companies and/or authorities on physicians, which impair the trust between the physician and his patient, are making the process more difficult. The issues of compliance, sexual harassment and unique problems of patient-doctor relations in psychiatry are the other subtopics in the article. The cross-cultural aspects of patient-doctor relations and encountered clinical problems are discussed with case examples particularly about Turkish immigrants, who live in Germany. Suggestions for psychiatrists in Germany to work out the challenges facing them are presented in the conclusion.

  8. Colored Contact Lens Dangers

    Full Text Available ... Cleveland. "This is far from the truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager ... about the members of the eye-care team . Consumer warning about the improper use of colored contact ...

  9. Colored Contact Lens Dangers

    Full Text Available ... Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Leer en Español: Peligros asociados ... truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager Blinded In One Eye By Non- ...

  10. Colored Contact Lens Dangers

    ... Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Leer en Español: Peligros asociados ... truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager Blinded In One Eye By Non- ...

  11. Colored Contact Lens Dangers

    Full Text Available ... Cleveland. "This is far from the truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager ... the lenses. Never share contact lenses with another person. Get follow up exams with your eye care ...

  12. Associations between causal attributions and personal stigmatizing attitudes in untreated persons with current mental health problems.

    Stolzenburg, Susanne; Freitag, Simone; Schmidt, Silke; Schomerus, Georg

    2018-02-01

    Past research has shown that among the general public, certain causal explanations like biomedical causes are associated with stronger desire for social distance from persons with mental illness. Aim of this study was to find out how different causal attributions of persons with untreated mental health problems regarding their own complaints are associated with stigmatizing attitudes, anticipated self-stigma when seeking help and perceived stigma-stress. Altogether, 207 untreated persons with a current depressive syndrome were interviewed. Biomedical causes, but also belief in childhood trauma or unhealthy behavior as a cause of the problem, were associated with stronger personal stigma and with more stigma-stress. Similarities and differences to findings among the general population and implications for future research are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Current problems in semiconductor detectors for high energy physics after particle irradiations

    Lazanu, Ionel

    2002-01-01

    The use of semiconductor materials as detectors in high radiation environments, as expected in future high energy accelerators or in space missions, poses severe problems in long-time operations, due to changes in the properties of the material, and consequently in the performances of detectors. This talk presents the major theoretical areas of current problems, reviews the works in this field and the stage of their understanding, including author's contributions The mechanisms of interaction of the projectile with the semiconductor, the production of primary defects, the physical quantities and the equations able to characterise and describe the radiation effects, and the equations of kinetics of defects are considered. Correlation between microscopic damage and detector performances and the possible ways to optimise the radiation hardness of materials are discussed. (author)

  14. Discretization and numerical realization of contact problems for elastic-perfectly plastic bodies. PART II - numerical realization, limit analysis

    Čermák, M.; Haslinger, Jaroslav; Kozubek, T.; Sysala, Stanislav

    2015-01-01

    Roč. 95, č. 12 (2015), s. 1348-1371 ISSN 0044-2267 R&D Projects: GA ČR GA13-18652S Institutional support: RVO:68145535 Keywords : frictionless contact * alternating direction method of multipliers * limit load analysis * elastic-perfect analplasticity Subject RIV: BA - General Mathematics Impact factor: 1.293, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/zamm.201400069/epdf

  15. Assessment of methods for computing the closest point projection, penetration, and gap functions in contact searching problems

    Kopačka, Ján; Gabriel, Dušan; Plešek, Jiří; Ulbin, M.

    2016-01-01

    Roč. 105, č. 11 (2016), s. 803-833 ISSN 0029-5981 R&D Projects: GA ČR(CZ) GAP101/12/2315; GA MŠk(CZ) ME10114 Institutional support: RVO:61388998 Keywords : closest point projection * local contact search * quadratic elements * Newtons methods * geometric iteration methods * simplex method Subject RIV: JC - Computer Hardware ; Software Impact factor: 2.162, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/nme.4994/abstract

  16. Towards a more accurate microscopic description of the moving contact line problem - incorporating nonlocal effects through a statistical mechanics framework

    Nold, Andreas; Goddard, Ben; Sibley, David; Kalliadasis, Serafim

    2014-03-01

    Multiscale effects play a predominant role in wetting phenomena such as the moving contact line. An accurate description is of paramount interest for a wide range of industrial applications, yet it is a matter of ongoing research, due to the difficulty of incorporating different physical effects in one model. Important small-scale phenomena are corrections to the attractive fluid-fluid and wall-fluid forces in inhomogeneous density distributions, which often previously have been accounted for by the disjoining pressure in an ad-hoc manner. We systematically derive a novel model for the description of a single-component liquid-vapor multiphase system which inherently incorporates these nonlocal effects. This derivation, which is inspired by statistical mechanics in the framework of colloidal density functional theory, is critically discussed with respect to its assumptions and restrictions. The model is then employed numerically to study a moving contact line of a liquid fluid displacing its vapor phase. We show how nonlocal physical effects are inherently incorporated by the model and describe how classical macroscopic results for the contact line motion are retrieved. We acknowledge financial support from ERC Advanced Grant No. 247031 and Imperial College through a DTG International Studentship.

  17. Storage and treatment of SNF of Alfa class nuclear submarines: current status and problems

    Ignatiev, Sviatoslav; Zabudko, Alexey; Pankratov, Dmitry; Somov, Ivan; Suvorov, Gennady

    2007-01-01

    Available in abstract form only. Full text of publication follows: The current status and main problems associated with storage, defueling and following treatment of spent nuclear fuel (SNF) of Nuclear Submarines (NS) with heavy liquid metal cooled reactors are considered. In the final analysis these solutions could be realized in the form of separate projects to be funded through national and bi- and multilateral funding in the framework of the international collaboration of the Russian Federation on complex utilization of NS and rehabilitation of contaminated objects allocated in the North-West region of Russia. (authors)

  18. Eddy-current testing of fatigue degradation upon contact fatigue loading of gas powder laser clad NiCrBSi-Cr3C2 composite coating

    Savrai, R. A.; Makarov, A. V.; Gorkunov, E. S.; Soboleva, N. N.; Kogan, L. Kh.; Malygina, I. Yu.; Osintseva, A. L.; Davydova, N. A.

    2017-12-01

    The possibilities of the eddy-current method for testing the fatigue degradation under contact loading of gas powder laser clad NiCrBSi-Cr3C2 composite coating with 15 wt.% of Cr3C2 additive have been investigated. It is shown that the eddy-current testing of the fatigue degradation under contact loading of the NiCrBSi-15%Cr3C2 composite coating can be performed at high excitation frequencies 72-120 kHz of the eddy-current transducer. At that, the dependences of the eddy-current instrument readings on the number of loading cycles have both downward and upward branches, with the boundary between the branches being 3×105 cycles in the given loading conditions. This is caused, on the one hand, by cracking, and, on the other hand, by cohesive spalling and compaction of the composite coating, which affect oppositely the material resistivity and, correspondingly, the eddy-current instrument readings. The downward branch can be used to monitor the processes of crack formation and growth, the upward branch - to monitor the degree of cohesive spalling, while taking into account in the testing methodology an ambiguous character of the dependences of the eddy-current instrument readings on the number of loading cycles.

  19. Field, temperature, and angle dependent critical current density Jc(H,T,θ) in coated conductors obtained via contact-free methods

    Thompson, J R; Christen, D K; Zhang Yifei; Zuev, Y L; Cantoni, C; Sinclair, J W; Chen Yimin; Selvamanickam, V

    2010-01-01

    Applications of coated conductors based on high- T c superconductors often require detailed knowledge of their critical current density J c as a function of magnetic field orientation as well as field strength and temperature. This work demonstrates experimental methods for obtaining the angularly dependent J c using contact-free magnetic measurements, and qualifies those methods using several well defined conditions. The studies complement traditional transport techniques and are readily extended to conditions of field and temperature where the current density is very large and transport methods become difficult. Results on representative materials are presented.

  20. Field, temperature, and angle dependent critical current density Jc(H,T, ) in coated conductors obtained via contact-free methods

    Thompson, James R [ORNL; Sinclair IV, John W [ORNL; Christen, David K [ORNL; Zhang, Yifei [ORNL; Zuev, Yuri L [ORNL; Cantoni, Claudia [ORNL; Chen, Y [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2010-01-01

    Applications of coated conductors based on high-Tc superconductors often require detailed knowledge of their critical current density Jc as a function of magnetic field orientation as well as field strength and temperature. This work demonstrates experimental methods to obtain the angularly dependent Jc using contact-free magnetic measurements, and qualifies those methods using several well defined conditions. The studies complement traditional transport techniques and are readily extended to conditions of field and temperature where the current density is very large and transport methods become difficult. Results on representative materials are presented.

  1. Field, temperature, and angle dependent critical current density J{sub c}(H,T,{theta}) in coated conductors obtained via contact-free methods

    Thompson, J R; Christen, D K; Zhang Yifei; Zuev, Y L; Cantoni, C [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6092 (United States); Sinclair, J W [Department of Physics, University of Tennessee, Knoxville, TN 37996-1200 (United States); Chen Yimin; Selvamanickam, V [SuperPower, Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States)

    2010-01-15

    Applications of coated conductors based on high- T{sub c} superconductors often require detailed knowledge of their critical current density J{sub c} as a function of magnetic field orientation as well as field strength and temperature. This work demonstrates experimental methods for obtaining the angularly dependent J{sub c} using contact-free magnetic measurements, and qualifies those methods using several well defined conditions. The studies complement traditional transport techniques and are readily extended to conditions of field and temperature where the current density is very large and transport methods become difficult. Results on representative materials are presented.

  2. Finite element solution of nonlinear eddy current problems with periodic excitation and its industrial applications.

    Bíró, Oszkár; Koczka, Gergely; Preis, Kurt

    2014-05-01

    An efficient finite element method to take account of the nonlinearity of the magnetic materials when analyzing three-dimensional eddy current problems is presented in this paper. The problem is formulated in terms of vector and scalar potentials approximated by edge and node based finite element basis functions. The application of Galerkin techniques leads to a large, nonlinear system of ordinary differential equations in the time domain. The excitations are assumed to be time-periodic and the steady-state periodic solution is of interest only. This is represented either in the frequency domain as a finite Fourier series or in the time domain as a set of discrete time values within one period for each finite element degree of freedom. The former approach is the (continuous) harmonic balance method and, in the latter one, discrete Fourier transformation will be shown to lead to a discrete harmonic balance method. Due to the nonlinearity, all harmonics, both continuous and discrete, are coupled to each other. The harmonics would be decoupled if the problem were linear, therefore, a special nonlinear iteration technique, the fixed-point method is used to linearize the equations by selecting a time-independent permeability distribution, the so-called fixed-point permeability in each nonlinear iteration step. This leads to uncoupled harmonics within these steps. As industrial applications, analyses of large power transformers are presented. The first example is the computation of the electromagnetic field of a single-phase transformer in the time domain with the results compared to those obtained by traditional time-stepping techniques. In the second application, an advanced model of the same transformer is analyzed in the frequency domain by the harmonic balance method with the effect of the presence of higher harmonics on the losses investigated. Finally a third example tackles the case of direct current (DC) bias in the coils of a single-phase transformer.

  3. Temperature, pressure, and density of electron, atom and ion, in the breaking arc of silver-cadmium contacts used in medium current region

    Aida, Teizo

    1979-01-01

    Wear of silver-cadmium contacts at the time of breaking was studied. The materials of the contacts were silver-cadmium alloy and silver-cadmium oxide sinter. The spectra of arc discharge generated at the time of breaking contact were analyzed with a monochromator photo multiplier. The ratio of the densities of cadmium and silver atoms in the arc can be estimated from the observed intensities of spectrum lines. The electron density is obtained from the arc current density. The proportion of the cadmium atoms in the arc was about 30 percent. The densities of silver atoms and cadmium atoms can be estimated by the principle of thermal ionization equilibrium. The ion densities were also estimated. The partial pressures of silver and cadmium atoms in the arc can be obtained from the Boyle-Charles' law. A formula which gives the number of atoms liberated from the surfaces of contacts at the time of breaking was given by Boddy et al. (Kato, T.)

  4. Current Crisis in Science Education? Women in Science and Problems for the Behavioral Scientists. Some Perspectives of a Physicist.

    Dresselhaus, Mildred S.

    A number of problems exist in society which require the cooperation of physical and social scientists. One of these problems is the current crisis in science education. There are several aspects to this problem, including the declining interest of students in math and science at a time when functioning in our society requires more, not less,…

  5. Numerical analysis of some problems related to the mechanics of pneumatic tires: Finite deformation/rolling contact of a viscoelastic cylinder and finite deformation of cord-reinforced rubber composites

    Oden, J. T.; Becker, E. B.; Lin, T. L.; Hsieh, K. T.

    1984-01-01

    The formulation and numerical analysis of several problems related to the behavior of pneumatic tires are considered. These problems include the general rolling contact problem of a rubber-like viscoelastic cylinder undergoing finite deformations and the finite deformation of cord-reinforced rubber composites. New finite element models are developed for these problems. Numerical results obtained for several representative cases are presented.

  6. Investigation of the primary plasticisers present in polyvinyl chloride (PVC) products currently authorised as food contact materials.

    Carlos, Katherine S; de Jager, Lowri S; Begley, Timothy H

    2018-03-15

    PVC is a common food contact material that is usually plasticised to increase its flexibility. Phthalates are one class of chemical compounds that are often used as plasticisers in PVC in a wide range of industries. They may be used in packaging materials for foods and can also be found in components of certain food processing equipment such as conveyor belts and tubing. Transfer of plasticisers from packaging to foods can occur. In recent years, there has been increased interest in understanding the health effects of phthalates, as well as the possible human exposure levels. However, there is limited information available about the routes of exposure to phthalates. In July 2014, the Chronic Hazard Advisory Panel (CHAP) produced a report for the U.S. Consumer Product Safety Commission detailing the potential health hazards of phthalates and phthalate alternatives. This report listed diet as one factor contributing greater than or equal to 10% of total phthalate exposure. As a result of this report, the U.S. Food and Drug Administration (FDA) is interested in determining the types of the primary plasticiser present in food packaging and processing materials as well as their concentrations. An investigation was conducted of 56 different samples of PVC food packaging and food processing materials available in the US market using a solvent extraction and GC-MS analysis. Nine different plasticisers including three phthalates, di(2-ethylhexyl) phthalate, diisononyl phthalate and diisodecyl phthalate, were identified in the products tested. The plasticiser concentrations ranged from 1 to 53% depending on the types of food contact materials and the type of plasticiser. Overall, it appears that manufacturers are switching away from phthalates as their primary plasticiser to alternate compounds such as ESBO, ATBC, DEHT, DINCH, DEHA and DINA.

  7. Current induced multi-mode propagating spin waves in a spin transfer torque nano-contact with strong perpendicular magnetic anisotropy

    Mohseni, S. Morteza; Yazdi, H. F.; Hamdi, M.; Brächer, T.; Mohseni, S. Majid

    2018-03-01

    Current induced spin wave excitations in spin transfer torque nano-contacts are known as a promising way to generate exchange-dominated spin waves at the nano-scale. It has been shown that when these systems are magnetized in the film plane, broken spatial symmetry of the field around the nano-contact induced by the Oersted field opens the possibility for spin wave mode co-existence including a non-linear self-localized spin-wave bullet and a propagating mode. By means of micromagnetic simulations, here we show that in systems with strong perpendicular magnetic anisotropy (PMA) in the free layer, two propagating spin wave modes with different frequency and spatial distribution can be excited simultaneously. Our results indicate that in-plane magnetized spin transfer nano-contacts in PMA materials do not host a solitonic self-localized spin-wave bullet, which is different from previous studies for systems with in plane magnetic anisotropy. This feature renders them interesting for nano-scale magnonic waveguides and crystals since magnon transport can be configured by tuning the applied current.

  8. Contact materials for nanoelectronics

    Alshareef, Husam N.; Quevedo-Ló pez, Manuel Angel Quevedo; Majhi, Prashant

    2011-01-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena

  9. An evaluation of quasi-Newton methods for application to FSI problems involving free surface flow and solid body contact

    Bogaers, Alfred EJ

    2016-09-01

    Full Text Available the respective outward pointing normals along Γs and Γf if the solid and fluid interfaces are non-matching, Γs 6= Γf . In this paper, the fluid operator F is solved using OpenFOAM where Calculix is used for the structural analysis. The interface load and motion... differ only on the basis of how information from multiple time steps are retained. 4 Test Problems The test problems in the sections to follow have been performed using OpenFOAM [1] for the fluid domain and Calculix [22] for the structural domain...

  10. Patch testing with markers of fragrance contact allergy. Do clinical tests correspond to patients' self-reported problems?

    Johansen, J D; Andersen, T F; Veien, Niels

    1997-01-01

    The aim of the present study was to investigate the relationship between patients' own recognition of skin problems using consumer products and the results of patch testing with markers of fragrance sensitization. Eight hundred and eighty-four consecutive eczema patients, 18-69 years of age, filled...

  11. Patch testing with markers of fragrance contact allergy. Do clinical tests correspond to patients' self-reported problems?

    Johansen, J D; Andersen, T F; Veien, Niels

    1997-01-01

    The aim of the present study was to investigate the relationship between patients' own recognition of skin problems using consumer products and the results of patch testing with markers of fragrance sensitization. Eight hundred and eighty-four consecutive eczema patients, 18-69 years of age, fill...

  12. An overview of the formulation, existence and uniqueness issues for the initial value problem raised by the dynamics of discrete systems with unilateral contact and dry friction

    Ballard, Patrick; Charles, Alexandre

    2018-03-01

    In the end of the seventies, Schatzman and Moreau undertook to revisit the venerable dynamics of rigid bodies with contact and dry friction in the light of more recent mathematics. One claimed objective was to reach, for the first time, a mathematically consistent formulation of an initial value problem associated with the dynamics. The purpose of this article is to make a review of the today state-of-art concerning not only the formulation, but also the issues of existence and uniqueness of solution. xml:lang="fr"

  13. Current situation and problems of cancer-reproductive therapy from the standpoint of male reproductive therapy

    Shin, Takeshi; Tanaka, Takashi; Nishio, Koujiro; Arai, Manabu; Okada, Horoshi; Nozaki, Miwako; Kaji, Yasushi

    2017-01-01

    This paper reviewed the current situation and problems of cancer - reproductive therapy from the standpoint of male reproductive therapy. Common causes for male infertility include spermatogenic dysfunction, seminal duct dysfunction, and sexual dysfunction. Causes of male infertility in cancer patients include the presence of cancer itself, as well as pathological conditions due to surgery, radiation therapy, or chemotherapy for cancer, namely spermatogenic dysfunction, seminal duct dysfunction, and sexual dysfunction. The American Society of Clinical Oncology (ASCO) presents the risk classification of infertility due to anti-cancer drugs or radiotherapy. Cancer treating physicians evaluate infertility risk associated with treatment according to this risk classification and provide patients with information. If a patient wishes to preserve fertility, it is recommended in ASCO's fertility preservation guidelines to introduce the facilities that can store frozen sperm. Questionnaire surveys on sperm cryopreservation to blood physician show that the description of sperm cryopreservation is made at only about two-thirds of facilities and there is a problem that the systemization of cryopreservation has not progressed. The only way to acquire a baby in a patient who has undergone cancer treatment without cryopreservation and became permanent azoospermia is microscopic testis sperm collection and microinsemination. (A.O.)

  14. Investigation of tunneling current and local contact potential difference on the TiO2(110) surface by AFM/KPFM at 78 K.

    Wen, Huan Fei; Li, Yan Jun; Arima, Eiji; Naitoh, Yoshitaka; Sugawara, Yasuhiro; Xu, Rui; Cheng, Zhi Hai

    2017-03-10

    We propose a new multi-image method for obtaining the frequency shift, tunneling current and local contact potential difference (LCPD) on a TiO 2 (110) surface with atomic resolution. The tunneling current image reveals rarely observed surface oxygen atoms contrary to the conventional results. We analyze how the surface and subsurface defects affect the distribution of the LCPD. In addition, the subsurface defects are observed clearly in the tunneling current image, in contrast to a topographic image. To clarify the origin of the atomic contrast, we perform site-dependent spectroscopy as a function of the tip-sample distance. The multi-image method is expected to be widely used to investigate the charge transfer phenomena between the nanoparticles and surface sites, and it is useful for elucidating the mechanisms of catalytic reactions.

  15. High aspect ratio problem in simulation of a fault current limiter based on superconducting tapes

    Velichko, A V; Coombs, T A

    2006-01-01

    We are offering a solution for the high-aspect-ratio problem relevant to the numerical simulation of AC loss in superconductors and metals with high aspect (width-to-thickness) ratio. This is particularly relevant to simulation of fault current limiters (FCLs) based on second generation YBCO tapes on RABiTS. By assuming a linear scaling of the electric and thermal properties with the size of the structure, we can replace the real sample with an effective sample of a reduced aspect ratio by introducing size multipliers into the equations that govern the physics of the system. The simulation is performed using both a proprietary equivalent circuit software and a commercial FEM software. The correctness of the procedure is verified by simulating temperature and current distributions for samples with all three dimensions varying within 10 -3 -10 3 of the original size. Qualitatively the distributions for the original and scaled samples are indistinguishable, whereas quantitative differences in the worst case do not exceed 10%

  16. High aspect ratio problem in simulation of a fault current limiter based on superconducting tapes

    Velichko, A V; Coombs, T A [Electrical Engineering Division, University of Cambridge (United Kingdom)

    2006-06-15

    We are offering a solution for the high-aspect-ratio problem relevant to the numerical simulation of AC loss in superconductors and metals with high aspect (width-to-thickness) ratio. This is particularly relevant to simulation of fault current limiters (FCLs) based on second generation YBCO tapes on RABiTS. By assuming a linear scaling of the electric and thermal properties with the size of the structure, we can replace the real sample with an effective sample of a reduced aspect ratio by introducing size multipliers into the equations that govern the physics of the system. The simulation is performed using both a proprietary equivalent circuit software and a commercial FEM software. The correctness of the procedure is verified by simulating temperature and current distributions for samples with all three dimensions varying within 10{sup -3}-10{sup 3} of the original size. Qualitatively the distributions for the original and scaled samples are indistinguishable, whereas quantitative differences in the worst case do not exceed 10%.

  17. A study of some political problems considering current geographical analytical parameters

    Héctor Adolfo Dupuy

    2008-01-01

    Full Text Available This paper intends to study some of the main problems presented, on different scales, by current politics, considering the spatial implications as well as various parameters offered lately by the geographical science. The proposal is supported by the theoretical bases developed from Emmanuel Wallerstein and Peter Taylor's statement about a world system structured as a world economy, based on the capitalist mode of production. Conversely, it attempts to provide a theoretical explanation for the dynamics experienced by the territories upon thee basis of such world system's mechanics. According to these assumptions, an analysis is proposed of some of the main phenomena resulting from the previous analysis and its spatial implications, such as the current power relations in the system, the subsistence of traditional power factors (Nation-states, ethnically based cultural configurations and the appearance of new ones (the forming of transnational blocs and associations, new social movements, new forms of local participation, the importance of hegemonic and counter-hegemonic discourses in the construction of symbolic representations and of the mass media in such processes or the new cultural identity and hybridization chart from population mobility.

  18. A New Method Solving Contact/Detach Problem in Fluid and Structure Interaction Simulation with Application in Modeling of a Safety Valve

    Zheng Guo

    2010-01-01

    Full Text Available A new virtual baffle methodology is implemented to solve contact/detach problem which is often encountered in fluid and structure interaction simulations while using dynamic grids technique. The algorithm is based on tetrahedral unstructured grid, and a zero thickness baffle face is generated between actually contacted two objects. In computation process, this baffle face is divided into two parts representing convective and blocked area, respectively; the area of each part is calculated according to the actual displacement between the two objects. Convective part in a baffle face is treated as inner interface between cells, and on blocked part wall boundary condition is applied; so convective and blocking effect can be achieved on a single baffle face. This methodology can simulate real detaching process starting from contact, that is, zero displacement, while it has no restriction to minimum grid cell size. The methodology is then applied in modeling of a complicated safety valve opening process, involving multidisciplinary fluid and structure interaction and dynamic grids. The results agree well with experimental data, which proves that the virtual baffle method is successful.

  19. Current identification in vacuum circuit breakers as a least squares problem*

    Ghezzi Luca

    2013-01-01

    Full Text Available In this work, a magnetostatic inverse problem is solved, in order to reconstruct the electric current distribution inside high voltage, vacuum circuit breakers from measurements of the outside magnetic field. The (rectangular final algebraic linear system is solved in the least square sense, by involving a regularized singular value decomposition of the system matrix. An approximated distribution of the electric current is thus returned, without the theoretical problem which is encountered with optical methods of matching light to temperature and finally to current density. The feasibility is justified from the computational point of view as the (industrial goal is to evaluate whether, or to what extent in terms of accuracy, a given experimental set-up (number and noise level of sensors is adequate to work as a “magnetic camera” for a given circuit breaker. Dans cet article, on résout un problème inverse magnétostatique pour déterminer la distribution du courant électrique dans le vide d’un disjoncteur à haute tension à partir des mesures du champ magnétique extérieur. Le système algébrique (rectangulaire final est résolu au sens des moindres carrés en faisant appel à une décomposition en valeurs singulières regularisée de la matrice du système. On obtient ainsi une approximation de la distribution du courant électrique sans le problème théorique propre des méthodes optiques qui est celui de relier la lumière à la température et donc à la densité du courant. La faisabilité est justifiée d’un point de vue numérique car le but (industriel est d’évaluer si, ou à quelle précision, un dispositif expérimental donné (nombre et seuil limite de bruit des senseurs peut travailler comme une “caméra magnétique” pour un certain disjoncteur.

  20. Electrochemistry of conductive polymers 39. Contacts between conducting polymers and noble metal nanoparticles studied by current-sensing atomic force microscopy.

    Cho, Shin Hyo; Park, Su-Moon

    2006-12-28

    Electrical properties of contacts formed between conducting polymers and noble metal nanoparticles have been examined using current-sensing atomic force microscopy (CS-AFM). Contacts formed between electrochemically prepared pi-conjugated polymer films such as polypyrrole (PPy), poly(3-methylthiophene) (P3MeT), as well as poly(3,4-ethylenedioxythiophene) (PEDOT) and noble metal nanoparticles including platinum (Pt), gold (Au), and silver (Ag) have been examined. The Pt nanoparticles were electrochemically deposited on a pre-coated PPy film surface by reducing a platinum precursor (PtCl62-) at a constant potential. Both current and scanning electron microscopic images of the film showed the presence of Pt islands. The Au and Ag nanoparticles were dispersed on the P3MeT and PEDOT film surfaces simply by dipping the polymer films into colloid solutions containing Au or Ag particles for specified periods (5 to approximately 10 min). The deposition of Au or Ag particles resulted from either their physical adsorption or chemical bonding between particles and the polymer surface depending on the polymer. When compared with PPy, P3MeT and PEDOT showed a stronger binding to Au or Ag nanoparticles when dipped in their colloidal solutions for the same period. This indicates that Au and Ag particles are predominantly linked with the sulfur atoms via chemical bonding. Of the two, PEDOT was more conductive at the sites where the particles are connected to the polymer. It appears that PEDOT has better aligned sulfur atoms on the surface and is strongly bonded to Au and Ag nanoparticles due to their strong affinity to gold and silver. The current-voltage curves obtained at the metal islands demonstrate that the contacts between these metal islands and polymers are ohmic.

  1. Steady sliding frictional contact problem for a 2d elastic half-space with a discontinuous friction coefficient and related stress singularities

    Ballard, Patrick

    2016-12-01

    The steady sliding frictional contact problem between a moving rigid indentor of arbitrary shape and an isotropic homogeneous elastic half-space in plane strain is extensively analysed. The case where the friction coefficient is a step function (with respect to the space variable), that is, where there are jumps in the friction coefficient, is considered. The problem is put under the form of a variational inequality which is proved to always have a solution which, in addition, is unique in some cases. The solutions exhibit different kinds of universal singularities that are explicitly given. In particular, it is shown that the nature of the universal stress singularity at a jump of the friction coefficient is different depending on the sign of the jump.

  2. Potential problems from shipment of high-curie content contact-handled transuranic (CH-TRU) waste to WIPP

    Neill, R.H.; Channell, J.K.

    1983-08-01

    There are about 1000 drums of contact-handled transuranic (CH-TRU) wastes containing more than 100 Ci/drum of Pu-238 that are stored at the Savannah River Plant and at the Los Alamos National Laboratory. Studies performed at DOE laboratories have shown that large quantities of gases are generated in stored drums containing 100 Ci of 238 Pu. Concentrations of hydrogen gas in the void space of the drums are often found to be high enough to be explosive. None of the analyses in the DOE WIPP Final Environmental Impact Statement, Safety Analysis Report, and Preliminary Transportation Analysis have considered the possibility that the generation of hydrogen gas by radiolysis may create an explosive or flammable hazard that could increase the frequency and severity of accidental releases of radionuclides during transportation or handling. These high 238 Pu concentration containers would also increase the estimated doses received by individuals and populations from transportation, WIPP site operations, and human intrusion scenarios even if the possibility of gas-enhanced releases is ignored. The WIPP Project Office has evaluated this effect on WIPP site operations and is suggesting a maximum limit of 140 239 Pu equivalent curies (P-Ci) per drum so that postulated accidental off-site doses will not be larger than those listed in the FEIS. The TRUPACT container, which is being designed for the transportation of CH-TRU wastes to WIPP, does not appear to meet the Nuclear Regulatory Commission regulations requiring double containment for the transportation of plutonium in quantities >20 Ci. A 20 alpha Ci/shipment limit would require about 200,000 shipments for the 4 million curies of alpha emitters slated for WIPP

  3. Overview of the problems related to the impact of geomagnetic induced current

    Kostić Vojin

    2017-01-01

    Full Text Available Geomagnetically induced currents (GICs can cause a range of adverse consequences related to the normal functioning of a power system, e.g. the saturation of power transformers, unusual flows of active and reactive power, voltage fluctuations, the appearance of the third harmonic, a shift of power frequency and erroneous operation of the protection relay. In the worst case, the above mentioned malfunctions may result in thermal destruction of the power transformers and heavy damage of parts or even the entire national power system. The same effect is particularly pronounced in high-voltage power facilities, whose neutral is effectively grounded, as is the case with substations rated voltage of 110 kV (owned by PE EPS, or 220 kV and 400 kV (owned by Joint Stock Company EMS. This paper gives a short overview of the problems related to the presence of GIC and possible preventive actions aimed at countering the potential adverse consequences caused by GIC.

  4. A Survey on Renewable Energy Development in Malaysia: Current Status, Problems and Prospects

    Alam Syed Shah

    2016-05-01

    Full Text Available Energy demand in Malaysia is increasing over seven per cent a year, while forty per cent of the energy is supplied from conventional fossil fuel. However, a number of social barriers have mired the social acceptance of renewable energy among the users. This study investigates the current status of renewable energy, problems and future outlook of renewable energy in Malaysia. A total of 200 respondents were surveyed from Klang Valley in Malaysia. Majority of the respondents use energy to generate electricity. Although some respondents reported using solar energy, there is lack of retail availability for solar energy. The findings show that limited information on renewable energy technologies, lack of awareness, and limited private sector engagement emerged as major barriers to sustainable renewable energy development. In addition, the respondents suggest for increasing policy support from the government to make information more accessible to mass users, provide economic incentives to investors and users, and promote small-community based renewable energy projects. The study suggests that the government begin small scale projects to build awareness on renewable energy, while academically, higher learning institutions include renewable energy syllabus in their academic curriculum. The study concluded that to have sustainable renewable energy development, government’s initiative, private sector engagement and users awareness must be given priority.

  5. A Survey on Renewable Energy Development in Malaysia: Current Status, Problems and Prospects

    Alam, Syed Shah; Nor, Nor Fariza Mohd; Ahmad, Maisarah; Hashim, Nik Hazrul Nik

    2016-05-01

    Energy demand in Malaysia is increasing over seven per cent a year, while forty per cent of the energy is supplied from conventional fossil fuel. However, a number of social barriers have mired the social acceptance of renewable energy among the users. This study investigates the current status of renewable energy, problems and future outlook of renewable energy in Malaysia. A total of 200 respondents were surveyed from Klang Valley in Malaysia. Majority of the respondents use energy to generate electricity. Although some respondents reported using solar energy, there is lack of retail availability for solar energy. The findings show that limited information on renewable energy technologies, lack of awareness, and limited private sector engagement emerged as major barriers to sustainable renewable energy development. In addition, the respondents suggest for increasing policy support from the government to make information more accessible to mass users, provide economic incentives to investors and users, and promote small-community based renewable energy projects. The study suggests that the government begin small scale projects to build awareness on renewable energy, while academically, higher learning institutions include renewable energy syllabus in their academic curriculum. The study concluded that to have sustainable renewable energy development, government's initiative, private sector engagement and users awareness must be given priority.

  6. The current situation of uranium resources exploration in East China: Problems, thought and countermeasure

    He Xiaomei; Mao Mengcai

    2014-01-01

    Based on analyzing the current situation of uranium resources and exploration effort in East China, the main existing problems, technical thought and countermeasure for the future exploration in East China are discussed in this paper. The degree of both uranium exploration and study in East China is relatively high, philosophy of scientific mineral-prospecting should be established in the new round of mineral prospecting. Under guidance of metallogenic theory of large mineralization cluster area and uranium metallogenic theory of multi-sources, previous data and research achievement should be analyzed and summarized. With the help of metallogenic model, useful methods and means should be applied to set up exploration model in order to realize news phase of model exploration, comprehensive exploration, 3D exploration and quantitative exploration. Efficiency of exploration of uranium resources should be strugglingly increased. High profitable uranium resources will be actively found with rich, shallow, near and easy features. The prospecting targets and strategy reserves of uranium resources will be increased in East China. (authors)

  7. Current standard rules of combined anteversion prevent prosthetic impingement but ignore osseous contact in total hip arthroplasty.

    Weber, Markus; Woerner, Michael; Craiovan, Benjamin; Voellner, Florian; Worlicek, Michael; Springorum, Hans-Robert; Grifka, Joachim; Renkawitz, Tobias

    2016-12-01

    In this prospective study of 135 patients undergoing cementless total hip arthroplasty (THA) we asked whether six current definitions of combined anteversion prevent impingement and increase postoperative patient individual impingement-free range-of-motion (ROM). Implant position was measured by an independent, external institute on 3D-CT performed six weeks post-operatively. Post-operative ROM was calculated using a CT-based algorithm detecting osseous and/or prosthetic impingement by virtual hip movement. Additionally, clinical ROM was evaluated pre-operatively and one-year post-operatively by a blinded observer. Combined component position of cup and stem according to the definitions of Ranawat, Widmer, Dorr, Hisatome and Yoshimine inhibited prosthetic impingement in over 90 %, while combined osseous and prosthetic impingement still occurred in over 40 % of the cases. The recommendations by Jolles, Widmer, Dorr, Yoshimine and Hisatome enabled higher flexion (p ≤ 0.001) and internal rotation (p ≤ 0.006). Clinically, anteversion rules of Widmer and Yoshimine provided one-year post-operatively statistically but not clinically relevant higher internal rotation (p ≤0.034). Standard rules of combined anteversion detect prosthetic but fail to prevent combined osseous and prosthetic impingement in THA. Future models will have to account for the patient-individual anatomic situation to ensure impingement-free ROM.

  8. Sistemas atuais de cuidados e manutenção de lentes de contato Current care and maintenance systems for contact lenses

    César Lipener

    2008-12-01

    Full Text Available A correta manutenção das lentes de contato é fundamental para se obter sucesso e manter a continuidade de seu uso. É grande o número de pacientes que abandonam o uso de suas lentes por problemas que poderiam ser solucionados com tratamentos relativamente simples ou com uma orientação mais adequada. O mau uso das lentes, associado à má adaptação, contaminação, doenças oculares prévias e fatores ambientais, podem aumentar o número de infecções corneanas através da proliferação de microorganismos. O presente artigo visa apresentar as atualizações em relação aos cuidados e manutenção com as lentes de contato.The proper maintenance of contact lenses is crucial for their success and to maintain the continuity of their use. Many patients abandon the use of their lenses due to problems that could be solved with relatively simple treatments. The misuse of lenses, coupled with poor adjustment, contamination, eye disease and environmental factors may increase the number of corneal infections through the proliferation of microorganisms. This article aims to provide contact lens care and maintenance updates.

  9. Language Contact.

    Nelde, Peter Hans

    1995-01-01

    Examines the phenomenon of language contact and recent trends in linguistic contact research, which focuses on language use, language users, and language spheres. Also discusses the role of linguistic and cultural conflicts in language contact situations. (13 references) (MDM)

  10. [POSTRESUSCITATION CICATRICIAL TRACHEAL STENOSIS. CURRENT STATE OF THE PROBLEM - THE SUCCESSES, THE HOPES AND DISAPPOINTMENTS.

    Parshin, V D; Vyzhigina, M A; Rusakov, M A; Parshin, V V; Titov, V A; Starostin, A V

    2016-09-01

    , the principle of "every patient his own version of operation" allows to minimize the risk oftreatment and to get a good lasting result. Proof of such provision may be the fact that the frequency of complications and postoperative mortality at our patients have had a tendency to decrease and currently stands at 12.9 and 0.7 %, respectively for many years. It is 2.3 and 9.6 times less, respectively, than in the periodfrom 1963 to 2000. It appears that further reduction of these indicators will be at a slower pace, afurther solution of the CTS problem will be based on the prevention of disease. Prevention of cicatricial tracheal stenosis in the departments of reanimation and intensive care is currently inadequate. It requires fundamentally new approaches, but reform still has not brought the desired results. Diagnosis of the CTS at an early stage allows early treatment and to avoid complex and risky operations. Increasingly important, apart tracheoscopy for diagnosis of tracheomalacia purchase dynamic computed tomography and magnetic resonance - tomography. Treatment ofpatients with CTS requires a multidisciplinary approach, individual selection operations for a particular patient. The general trend of the further development of tracheal surgery is associated with an increase in the number of simultaneous resections, including at the long, two-level stenosis, as well as at relapse. The patients who had refused treatment or have elected him palliative options made possible surgery. The frequency of postoperative comnlications and mortality decreased significantiv, including after extensive and traumatic operations on the trachea.

  11. Problem of construction of the operator of the electromagnetic current of a nucleus

    Korchin, A.Y.; Shebeko, A.V.

    1984-01-01

    The idea of R. G. Sachs [Phys. Rev. 74, 433 (1948)] in the phenomenological theory of exchange currents in nuclei is developed to obtain an expression for the Hamiltonian of a nucleus. An expression is obtained for the current which has the same isospin structure as the pion and seagull currents in the theory of meson exchange currents. Sachs' result follows for the case of point nucleons

  12. A current value Hamiltonian Approach for Discrete time Optimal Control Problems arising in Economic Growth

    Naz, Rehana

    2018-01-01

    Pontrygin-type maximum principle is extended for the present value Hamiltonian systems and current value Hamiltonian systems of nonlinear difference equations for uniform time step $h$. A new method termed as a discrete time current value Hamiltonian method is established for the construction of first integrals for current value Hamiltonian systems of ordinary difference equations arising in Economic growth theory.

  13. Courses for tutors in problem-based learning. Current challenges at four Swedish universities

    Helen Susan Setterud

    2015-06-01

    Full Text Available The key role of the tutor in problem-based learning (PBL is to help students become selfregulated learners. Tutors need training to acquire the necessary facilitating skills for this task. The aim of this article is to describe and discuss how PBL tutor training is currently arranged at four universities in Sweden: Linköping University, Lund Medical Faculty, Uppsala Medical School and Örebro School of Medicine. Moreover, we seek to analyse how the content and format of the tutor training courses correspond to the desired skills and competencies for PBL tutors described in the literature. We draw especially on work coming out of three pioneering universities for PBL: McMaster University, Canada; Maastricht University, The Netherlands; and Linköping University, Sweden. One aim has been to construct a framework for analysis that uses categories specifying the knowledge base, capabilities and skills to support students’ learning processes which characterise the full-fledged PBL tutor. For this framework, we have used the following categories: Knowledge of PBL and pedagogical theories, Personal traits, Student-centeredness, Ability to handle group processes, and Subject knowledge. We collected descriptions of the course design and content from the four universities, and assessed to what extent these categories were represented within the courses. Our results show that all categories inform the course content at all four universities, though the design varies between courses. In summary, we show that the four PBL tutor training courses are all designed to enable participants to experience PBL first-hand both as members of a tutorial group and as tutors. They all also include a theoretical base and offer opportunities for discussion and reflection with peers; however, there are some differences in design between the courses. According to participants, all four courses provide good preparation for the tutor role. Yet, we see a need for the

  14. Current patch test results with the European baseline series and extensions to it from the 'European Surveillance System on Contact Allergy' network, 2007-2008

    Uter, Wolfgang; Aberer, Werner; Armario-Hita, José Carlos

    2012-01-01

    The pattern of contact sensitization to the supposedly most important allergens assembled in the baseline series differs between countries, presumably at least partly because of exposure differences. Objectives. To describe the prevalence of contact sensitization to allergens tested in consecutiv...

  15. Current patch test results with the European baseline series and extensions to it from the 'European Surveillance System on Contact Allergy' network, 2007-2008

    Uter, Wolfgang; Aberer, Werner; Armario-Hita, José Carlos; Fernandez-Vozmediano, José M; Ayala, Fabio; Balato, Anna; Bauer, Andrea; Ballmer-Weber, Barbara; Beliauskiene, Aiste; Fortina, Anna Belloni; Bircher, Andreas; Brasch, Jochen; Chowdhury, Mahbub M U; Coenraads, Pieter-Jan; Schuttelaar, Marie-Louise; Cooper, Sue; Czarnecka-Operacz, Magda; Zmudzinska, Maria; Elsner, Peter; English, John S C; Frosch, Peter J; Fuchs, Thomas; García-Gavín, Juan; Fernández-Redondo, Virginia; Gawkrodger, David J; Giménez-Arnau, Ana; Green, Cathy M; Horne, Helen L; Johansen, Jeanne Duus; Jolanki, Riitta; Pesonen, Maria; King, Clodagh M; Krêcisz, Beata; Chomiczewska, Dorota; Kiec-Swierczynska, Marta; Larese, Francesca; Mahler, Vera; Ormerod, Anthony D; Peserico, Andrea; Rantanen, Tapio; Rustemeyer, Thomas; Sánchez-Pérez, Javier; Sansom, Jane E; Silvestre, Juan Fco; Simon, Dagmar; Spiewak, Radoslaw; Statham, Barry N; Stone, Natalie; Wilkinson, Mark; Schnuch, Axel

    BACKGROUND: The pattern of contact sensitization to the supposedly most important allergens assembled in the baseline series differs between countries, presumably at least partly because of exposure differences. Objectives. To describe the prevalence of contact sensitization to allergens tested in

  16. Current problems of teaching spelling in the first cycle of Primary Education

    Martha Valcárcel González

    2005-12-01

    Full Text Available This article presents from the theoretical point of view the spelling problem as one of the main difficulties that there is in Primary Education and in which teachers intensively work searching for solutions.

  17. THE POTENTIAL OF APPLYING UTILITARIANISM IN BUSINESS ETHICS: THE CURRENT STATE OF THE PROBLEM

    Ларионов, Larionov Igor, Игорь Юрьевич

    2015-01-01

    In this paper, the use of utilitarianism in contemporary business ethics is described and the conditions under which it could be applied in business ethics most effectively are identified. In order to provide the conditions for its application the scope of problems that should be taken into account and solved are identified. The types of rationality in utilitarian ethics and utilitarian approach to the role of moral subject are also analyzed. Along with that the problem of moral motivation in...

  18. A comprehensive study of charge trapping in organic field-effect devices with promising semiconductors and different contact metals by displacement current measurements

    Bisoyi, Sibani; Tiwari, Shree Prakash; Rödel, Reinhold; Zschieschang, Ute; Klauk, Hagen; Kang, Myeong Jin; Takimiya, Kazuo

    2016-01-01

    A systematic and comprehensive study on the charge-carrier injection and trapping behavior was performed using displacement current measurements in long-channel capacitors based on four promising small-molecule organic semiconductors (pentacene, DNTT, C 10 -DNTT and DPh-DNTT). In thin-film transistors, these semiconductors showed charge-carrier mobilities ranging from 1.0 to 7.8 cm 2 V −1 s −1 . The number of charges injected into and extracted from the semiconductor and the density of charges trapped in the device during each measurement were calculated from the displacement current characteristics and it was found that the density of trapped charges is very similar in all devices and of the order 10 12 cm −2 , despite the fact that the four semiconductors show significantly different charge-carrier mobilities. The choice of the contact metal (Au, Ag, Cu, Pd) was also found to have no significant effect on the trapping behavior. (paper)

  19. Petroleum industry's current progress and challenges in dealing with the year 2000 problem

    Kraus, D.I.; Radu, C.G.; McKenzie, S.; Stuart, K.

    1998-01-01

    The steps that some major oil companies in Canada have taken to prepare their computers and automated equipment for the year 2000 (Y2K) are described. It is acknowledged that with 1700 retail service stations, over 300 wholesale operations, and 26 terminals, the extent of the problem is great. In addition some 38 upstream and 65 downstream applications have been identified as mission critical, not counting the 30 mission critical control systems in the upstream field operations and approximately the same number of operations in the downstream refinery. The good news is that remediation and testing is well underway nationally and the Calgary test laboratory will be commercially available in 1999. Getting management on-side, selling the positive aspects of Y2K, making good use of reputable consulting companies, keeping employees properly informed of problems and progress, are some of the key criteria in solving Y2K problems successfully

  20. Current ethical and other problems in the practice of African traditional medicine.

    Omonzejele, Peter

    2003-01-01

    Medicine in Africa is regarded as possessing its own "life force", not just using a system of prescribing. This is because health problems are not only attributed to pathological explanations alone, but also to other "forces". Hence, traditional healers utter incantations to take care of negative forces which militate against achieving cure. Treatment in African traditional medicine (ATM) is holistic. It seeks to strike a balance between the patients' body, soul and spirit. The problems arise from the infiltration of charlatans into the field, the practice of using mystical explanations for ill-health, and inadequate knowledge of the properties and clinical use of herbal remedies. Despite its problems, ATM can work in parallel with orthodox medicine using its strengths rather than its weaknesses. ATM has to be applied within a uniform ethical system. Practitioners of ATM must follow the principles of autonomy and confidentiality.

  1. Sausage instabilities in electron current channels and the problem of fast ignition

    Das, A.

    2002-01-01

    In the fast ignition concept of laser fusion, an intense picosecond laser pulse incident on an overdense pellet is absorbed by nonlinear mechanisms and gets converted into inward propagating fast electron currents. PIC simulations show that the return shielding currents due to cold plasma interact with the incoming currents and intense Weibel, tearing and coalescence instabilities take place, which organize the current into a few current channels. The stability of these current channels is thus a topic of great interest. We have carried out linear and nonlinear studies of 2 - dimensional sausage instabilities of a slab model of the current channels in the framework of electron magnetohydrodynamic fluid approximation. The analytic calculations and numerical simulations for some simple velocity profiles show the presence of linear instability driven by velocity shear. Nonlinear studies on the saturation of instabilities and their reaction back on the relaxation of the velocity profile have also been made. A discussion of the consequences of such EMHD turbulence induced relaxation and stopping of fast electrons, for the fast ignition concept will be presented. (author)

  2. A novel finite element method for moving conductor eddy current problems

    Liu, Z.; Eastham, A.R.; Dawson, G.E. (Queen' s Univ., Kingston, Ontario (Canada). Dept. of Electrical Engineering)

    1993-11-01

    A novel finite element method, as an alternative to upwinding, is proposed based on the elimination of the factors which could cause numerical oscillation and instability by properly choosing a set of unconventional weighting functions. The proposed method is first developed and verified for a one dimensional case and then extended to two dimensional problems. The calculation results for a 2D problem, along with the exact solutions and those obtained from Galerkin's and ''optimal'' upwinding methods, show that the proposed method is superior to the other two methods in terms of accuracy and freedom from oscillation.

  3. Perturbation-polynomial expansion formulation of 3-D eddy current problems

    Yeh, H.T.

    1977-01-01

    A pulsed magnetic field is required in Tokamak fusion machines. Eddy currents produced by the pulsed field may produce undesirable effects, e.g., in the mechanical loading of the vacuum vessel, heating in the magnet and structure, and field ripple in the plasma region. A method has been developed earlier to calculate the eddy current produced in a thin object by the linear ramping of a magnetic dipole. We report here extension of the method to calculate the eddy current induced in three-dimensional objects and by pulse coils of general shape. Examples are given

  4. The current situation and related problems of percutaneous vertebroplasty in clinical treatment of osteoporosis vertebral compression fracture

    Wang Luchang; Wu Chungen; Cheng Yongde

    2011-01-01

    As an effective, safe and less-invasive technique in interventional radiology, percutaneous vertebroplasty has satisfactory therapeutic results with fewer complications in treating osteoporosis vertebral compression fracture. This paper aims to make a comprehensive review of the current situation and related problems of percutaneous vertebroplasty in clinical treatment of osteoporosis vertebral compression fracture. (authors)

  5. Bully/Victim Problems among Preschool Children: A Review of Current Research Evidence

    Vlachou, Maria; Andreou, Eleni; Botsoglou, Kafenia; Didaskalou, Eleni

    2011-01-01

    Bullying in schools has been identified as a serious and complex worldwide problem associated with negative short- and long-term effects on children's psychosocial adjustment (Smith 1999; Ttofi and Farrington, "Aggressive Behav" 34(4):352-368, 2008). Entering kindergarten is a crucial developmental step in many children's lives mainly because it…

  6. Presymplectic current and the inverse problem of the calculus of variations

    Khavkine, I.

    2013-01-01

    The inverse problem of the calculus of variations asks whether a given system of partial differential equations (PDEs) admits a variational formulation. We show that the existence of a presymplectic form in the variational bicomplex, when horizontally closed on solutions, allows us to construct a

  7. Self-Monitoring Interventions for Students with Behavior Problems: A Systematic Review of Current Research

    Bruhn, Allison; McDaniel, Sara; Kreigh, Christi

    2015-01-01

    Explicitly teaching skills associated with self-determination has been promoted to support students' independence and control over their own lives. This is especially important for students with behavior problems. One self-determination skill or behavior that has been studied widely is self-monitoring. Although multiple reviews of various…

  8. Stroke care in Central Eastern Europe: current problems and call for action.

    Lenti, Laura; Brainin, Michael; Titianova, Ekaterina; Morovic, Sandra; Demarin, Vida; Kalvach, Pavel; Skoloudik, David; Kobayashi, Adam; Czlonkowska, Anna; Muresanu, Dafin F; Shekhovtsova, Ksenia; Skvortsova, Veronica I; Sternic, Nadezda; Beslac Bumbasirevic, Ljiljana; Svigelj, Viktor; Turcani, Peter; Bereczki, Dániel; Csiba, László

    2013-07-01

    Stroke is a major medical problem and one of the leading causes of mortality and disability all over in Europe. However, there are significant East-West differences in stroke care as well as in stroke mortality and morbidity rates. Central and Eastern European countries that formerly had centralized and socialist health care systems have serious and similar problems in organizing health and stroke care 20 years after the political transition. In Central and Eastern Europe, stroke is more frequent, the mortality rate is higher, and the victims are younger than in Western Europe. High-risk patients live in worse environmental conditions, and the socioeconomic consequences of stroke further weaken the economic development of these countries. To address these issues, a round table conference was organized. The main aim of this conference was to discuss problems to be solved related to acute and chronic stroke care in Central and Eastern European countries, and also, to exchange ideas on possible solutions. In this article, the discussed problems and possible solutions will be summarized, and introduce 'The Budapest Statement of Stroke Experts of Central and Eastern European countries'. © 2012 The Authors. International Journal of Stroke © 2012 World Stroke Organization.

  9. Current Situation, Problems and Solution Proposals of Kiwi Producer Associations in Turkey

    Erdal SIRAY

    2016-03-01

    Full Text Available Producer associations have an important role in adoption and implementation of new agricultural technologies. In Turkey, associations have contributed significantly to increase of kiwi production and its consumption in recent years. The most important function of kiwi producer associations is to assist their members in marketing of products as well as to try to provide solutions to problems related to kiwi production techniques. The data of this research was obtained from the 12 kiwi producer associations. According to the research results, the most important problem of kiwi producer associations is having financial difficulties. The associations, getting 79.4% of their incomes from the subscriptions, are unable to sufficiently perform their duties due to their limited budgets. The associations have indicated that the main problems in kiwi production are lack of knowledge for production techniques and qualified technical staff. There is no marketing problem of the product due to adequate domestic demand. But, the products should be disposed immediately due to lack of cold storage facilities and they are not sold at desired price.

  10. Mutual Inductance Problem for a System Consisting of a Current Sheet and a Thin Metal Plate

    Fulton, J. P.; Wincheski, B.; Nath, S.; Namkung, M.

    1993-01-01

    Rapid inspection of aircraft structures for flaws is of vital importance to the commercial and defense aircraft industry. In particular, inspecting thin aluminum structures for flaws is the focus of a large scale R&D effort in the nondestructive evaluation (NDE) community. Traditional eddy current methods used today are effective, but require long inspection times. New electromagnetic techniques which monitor the normal component of the magnetic field above a sample due to a sheet of current as the excitation, seem to be promising. This paper is an attempt to understand and analyze the magnetic field distribution due to a current sheet above an aluminum test sample. A simple theoretical model, coupled with a two dimensional finite element model (FEM) and experimental data will be presented in the next few sections. A current sheet above a conducting sample generates eddy currents in the material, while a sensor above the current sheet or in between the two plates monitors the normal component of the magnetic field. A rivet or a surface flaw near a rivet in an aircraft aluminum skin will disturb the magnetic field, which is imaged by the sensor. Initial results showed a strong dependence of the flaw induced normal magnetic field strength on the thickness and conductivity of the current-sheet that could not be accounted for by skin depth attenuation alone. It was believed that the eddy current imaging method explained the dependence of the thickness and conductivity of the flaw induced normal magnetic field. Further investigation, suggested the complexity associated with the mutual inductance of the system needed to be studied. The next section gives an analytical model to better understand the phenomenon.

  11. SAM Technical Contacts

    These technical contacts are available to help with questions regarding method deviations, modifications, sample problems or interferences, quality control requirements, the use of alternative methods, or the need to address analytes or sample types.

  12. Colored Contact Lens Dangers

    Full Text Available ... MD, professor of ophthalmology at Case Western Reserve University in Cleveland. "This is far from the truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager Blinded In ...

  13. Current Welfare Problems Facing Horses in Great Britain as Identified by Equine Stakeholders.

    Horseman, Susan V; Buller, Henry; Mullan, Siobhan; Whay, Helen R

    2016-01-01

    Despite growing concerns about the welfare of horses in Great Britain (GB) there has been little surveillance of the welfare status of the horse population. Consequently we have limited knowledge of the range of welfare problems experienced by horses in GB and the situations in which poor welfare occurs. Thirty-one in-depth interviews were conducted with a cross -section of equine stakeholders, in order to explore their perceptions of the welfare problems faced by horses in GB. Welfare problems relating to health, management and riding and training were identified, including horses being under or over weight, stabling 24 hours a day and the inappropriate use of training aids. The interviewees also discussed broader contexts in which they perceived that welfare was compromised. The most commonly discussed context was where horses are kept in unsuitable environments, for example environments with poor grazing. The racing industry and travellers horses were identified as areas of the industry where horse welfare was particularly vulnerable to compromise. Lack of knowledge and financial constraints were perceived to be the root cause of poor welfare by many interviewees. The findings give insight into the range of welfare problems that may be faced by horses in GB, the contexts in which these may occur and their possible causes. Many of the problems identified by the interviewees have undergone limited scientific investigation pointing to areas where further research is likely to be necessary for welfare improvement. The large number of issues identified suggests that some form of prioritisation may be necessary to target research and resources effectively.

  14. Current Welfare Problems Facing Horses in Great Britain as Identified by Equine Stakeholders

    Horseman, Susan V.; Buller, Henry

    2016-01-01

    Despite growing concerns about the welfare of horses in Great Britain (GB) there has been little surveillance of the welfare status of the horse population. Consequently we have limited knowledge of the range of welfare problems experienced by horses in GB and the situations in which poor welfare occurs. Thirty-one in-depth interviews were conducted with a cross -section of equine stakeholders, in order to explore their perceptions of the welfare problems faced by horses in GB. Welfare problems relating to health, management and riding and training were identified, including horses being under or over weight, stabling 24 hours a day and the inappropriate use of training aids. The interviewees also discussed broader contexts in which they perceived that welfare was compromised. The most commonly discussed context was where horses are kept in unsuitable environments, for example environments with poor grazing. The racing industry and travellers horses were identified as areas of the industry where horse welfare was particularly vulnerable to compromise. Lack of knowledge and financial constraints were perceived to be the root cause of poor welfare by many interviewees. The findings give insight into the range of welfare problems that may be faced by horses in GB, the contexts in which these may occur and their possible causes. Many of the problems identified by the interviewees have undergone limited scientific investigation pointing to areas where further research is likely to be necessary for welfare improvement. The large number of issues identified suggests that some form of prioritisation may be necessary to target research and resources effectively. PMID:27501387

  15. Numerical Modeling of Electrical Contact Conductance of Rough Bodies

    M. V. Murashov

    2015-01-01

    Full Text Available Since the beginning of the 20th century to the present time, efforts have been made to develop a model of the electrical contact conductance. The development of micro- and nanotechnologies make contact conductance problem more essential. To conduct borrowing from a welldeveloped thermal contact conductance models on the basis of thermal and electrical conductivity analogy is often not possible due to a number of fundamental differences. While some 3Dmodels of rough bodies deformation have been developed in one way or another, a 3D-model of the electrical conductance through rough bodies contact is still not. A spatial model of electrical contact of rough bodies is proposed, allows one to calculate the electrical contact conductance as a function of the contact pressure. Representative elements of the bodies are parallelepipeds with deterministic roughness on the contacting surfaces. First the non-linear elastic-plastic deformation of rough surface under external pressure is solved using the finite element software ANSYS. Then the solution of electrostatic problem goes on the same finite element mesh. Aluminum AD1 is used as the material of the contacting bodies with properties that account for cold work hardening of the surface. The numerical model is built within the continuum mechanics and nanoscale effects are not taken into account. The electrical contact conductance was calculated on the basis of the concept of electrical resistance of the model as the sum of the electrical resistances of the contacting bodies and the contact itself. It was assumed that there is no air in the gap between the bodies. The dependence of the electrical contact conductance on the contact pressure is calculated as well as voltage and current density distributions in the contact bodies. It is determined that the multi-asperity contact mode, adequate to real roughness, is achieved at pressures higher than 3MPa, while results within the single contact spot are

  16. The Effect of Postpartum Depression and Current Mental Health Problems of the Mother on Child Behaviour at Eight Years.

    Closa-Monasterolo, R; Gispert-Llaurado, M; Canals, J; Luque, V; Zaragoza-Jordana, M; Koletzko, B; Grote, V; Weber, M; Gruszfeld, D; Szott, K; Verduci, E; ReDionigi, A; Hoyos, J; Brasselle, G; Escribano Subías, J

    2017-07-01

    Background Maternal postpartum depression (PPD) could affect children's emotional development, increasing later risk of child psychological problems. The aim of our study was to assess the association between child's emotional and behavioural problems and mother's PPD, considering maternal current mental health problems (CMP). Methods This is a secondary analysis from the EU-Childhood Obesity Project (NCT00338689). Women completed the Edinburgh Postnatal Depression Scale (EPDS) at, 2, 3 and 6 months after delivery and the General Health Questionnaire (GHQ-12) to assess CMP once the children reached the age of 8 years. EPDS scores > 10 were defined as PPD and GHQ-12 scores > 2 were defined as CMP. The psychological problems of the children at the age of eight were collected by mothers through the Child's Behaviour Checklist (CBCL). Results 473, 474 and 459 mothers filled in GHQ-12 and CBCL tests at 8 years and EPDS at 2, 3 and 6 months, respectively. Anxiety and depression was significantly increased by maternal EPDS. Children whose mothers had both PPD and CMP exhibited the highest levels of psychological problems, followed by those whose mothers who had only CMP and only PPD. PPD and CMP had a significant effect on child's total psychological problems (p = 0.033, p mothers had PPD did not differ from children whose mothers did not have any depression. Conclusions Maternal postpartum depression and current mental health problems, separately and synergistically, increase children's psychological problems at 8 years.

  17. Existing contradictions and problems in China's current economic and social development

    Wang Tongsan

    2014-01-01

    Since the 18th National Congress of Communist Party of China (CPC),China has made important achievements and headway in economic and social development.However,now more than ever the focus should be on the conflicts and problems that continue to exist in China's economy.This paper examines six of them:(1) lack of a firm foundation for sustaining steady economic growth;(2) risks and hidden dangers in the financial,banking,and real estate sectors and massive overcapacity in some industries;(3) increasing difficulty in increasing agricultural production and raising rural incomes;(4) severe air,water,and soil pollution in certain regions and the arduous task of energy conservation and emissions reduction;(5) major structural problems constraining employment;and (6) issues of people's livelihood that have been the source of dissatisfaction for many Chinese citizens.

  18. Psychoeducational Services for Children and Youth in the Orient: Current Status, Problems, and some Remedies.

    Oakland, T; Hu, S

    1989-01-01

    Utilizing information obtained through an international survey and existing literature, patterns in the practices, research, and preparation of professionals who deliver psychoeducational services to children and youth in six Oriental countries (i.e., China, Hong Kong(1), Japan, the Philippines, Taiwan, and Thailand) are described. Services are provided by many professional groups. While few formal programs exist for the preparation of psychologists to work in schools, those providing such services have at least a bachelor's degree. Services commonly provided include assessment, vocational and educational guidance, counseling, parent education, and teaching. School psychological services generally are not governed by legislation or professional standards. Research tends to be applied and directed toward the construction and translations of tests and toward the needs of the mentally retarded, learning disabled, and behaviorally disordered. Ten major problems creating barriers for the delivery of psychoeducational services are identified. Three suggestions to help resolve these problems are offered.

  19. Applications of intelligent optimization in biology and medicine current trends and open problems

    Grosan, Crina; Tolba, Mohamed

    2016-01-01

    This volume provides updated, in-depth material on the application of intelligent optimization in biology and medicine. The aim of the book is to present solutions to the challenges and problems facing biology and medicine applications. This Volume comprises of 13 chapters, including an overview chapter, providing an up-to-date and state-of-the research on the application of intelligent optimization for bioinformatics applications, DNA based Steganography, a modified Particle Swarm Optimization Algorithm for Solving Capacitated Maximal Covering Location Problem in Healthcare Systems, Optimization Methods for Medical Image Super Resolution Reconstruction and breast cancer classification. Moreover, some chapters that describe several bio-inspired approaches in MEDLINE Text Mining, DNA-Binding Proteins and Classes, Optimized Tumor Breast Cancer Classification using Combining Random Subspace and Static Classifiers Selection Paradigms, and Dental Image Registration. The book will be a useful compendium for a broad...

  20. Two-dimensional effects in the problem of tearing modes control by electron cyclotron current drive

    Comisso, L.; Lazzaro, E.

    2010-01-01

    The design of means to counteract robustly the classical and neoclassical tearing modes in a tokamak by localized injection of an external control current requires an ever growing understanding of the physical process, beyond the Rutherford-type zero-dimensional models. Here a set of extended magnetohydrodynamic nonlinear equations for four continuum fields is used to investigate the two-dimensional effects in the response of the reconnecting modes to specific inputs of the localized external current. New information is gained on the space- and time-dependent effects of the external action on the two-dimensional structure of magnetic islands, which is very important to formulate applicable control strategies.

  1. Eddy current imaging. Limits of the born approximation and advantages of an exact solution to the inverse problem

    Hamman, E.; Zorgati, R.

    1995-01-01

    Eddy current non-destructive testing is used by EDF to detect flaws affecting conductive objects such as steam generator tubes. With a view to obtaining ever more accurate information on equipment integrity, thereby facilitating diagnosis, studies aimed at using measurements to reconstruct an image of the flaw have been proceeding now for about ten years. In this context, our approach to eddy current imaging is based on inverse problem formalism. The direct problem, involving a mathematical model linking measurements provided by a probe with variables characterizing the defect, is dealt with elsewhere. Using the model results, we study the possibility of inverting it, i.e. of reconstructing an image of the flaw from the measurements. We first give an overview of the different inversion techniques, representative of the state of the art and all based on linearization of the inverse problem by means of the Born approximation. The model error resulting from an excessive Born approximation nevertheless severely limits the quantity of the images which can be obtained. In order to counteract this often critical error and extend the eddy current imaging application field, we have to del with the non-linear inverse problem. A method derived from recent research is proposed and implemented to ensure consistency with the exact model. Based on an 'optimization' type approach and provided with a convergence theorem, the method is highly efficient. (authors). 17 refs., 7 figs., 1 append

  2. Adaptation of eddy current methods to the multiple problems of reactor testing

    Stumm, W.

    1975-01-01

    In reactor testing, the eddy current method is mainly used for the testing of surface regions inside the pressure vessel, on welds and joints, and for the testing of thin-walled pipes, e.g. the heat exchanger pipes. (RW/AK) [de

  3. A Synthesis of Language Learning Strategies: Current Issues, Problems and Claims Made in Learner Strategy Research

    Barjesteh, Hamed; Mukundan, Jayakaran; Vaseghi, Reza

    2014-01-01

    The current paper presented theoretical assumptions behind language learning strategies (LLS) and an overview of methods used to identify learners' strategies, first, and then summarized what have been reported from large number of descriptive studies of strategies by language learners. Moreover, the paper tried to present the variety of…

  4. [Current situations and problem analysis of influencing factors of traditional Chinese medicine tablets on forming quality].

    Li, Yan-Nian; Wu, Zhen-Feng; Wan, Na; Li, Yuan-Hui; Li, Hui-Ting; Yang, Ming

    2018-04-01

    The compressibility of tablets is the essential operating unit during the preparation of traditional Chinese medicine tablets, as well as a complicated process. Therefore, it is of great significance to comprehensively study the influencing factors on the formation process. This paper aimed to review the evaluation methods for the tablet forming quality and highlight the effects of material powder properties, excipients and preparation technology on the quality of traditional Chinese medicine tablets on the basis of relevant literatures. Furthermore, the common problems in tablet forming process are also analyzed to provide useful references for the development of tablet forming quality of traditional Chinese medicines. Copyright© by the Chinese Pharmaceutical Association.

  5. Current challenges and problems in teaching pathophysiology in Ukraine - another reaction to Churilov's paper.

    Ataman, Oleksandr V

    2017-12-01

    Pathophysiology in Ukraine has rich traditions and achievements in the scientific areas, as well as in teaching academic discipline. Its history, the main Ukrainian scientific schools and their famous representatives are briefly described. The content of existing study program, the main approaches to teaching, and some methodological and organizational problems needed to be solved are characterized. The necessity and usefulness of developing and implementing the three separate courses of discipline (Essential, Clinical and Advanced Pathophysiology) are substantiated. The place of Pathophysiology in the training of physicians with different kinds of their future activity is discussed. Relation of teaching Pathophysiology to Translational and Personalized Medicine is tried to be shown.

  6. Current state and problems of integrated development of mineral resources base in Russia

    Filimonova, I. V.; Eder, L. V.; Mishenin, M. V.; Mamakhatov, T. M.

    2017-09-01

    The article deals with the issues of integrated development of subsoil resources taking into account the actual problems facing the Russian oil and gas complex. The key factors determining the need for integrated development of subsoil resources have been systematized and investigated. These factors are the change of the hydrocarbon resource base quality, the improvement of the depletion degree of basic (unique and major) oil fields, the increase in the number of small and smallest oil fields discovered and introduced into development, the increased capital intensity and the riskiness of geological exploration, and the territorial location of new subsoil use facilities.

  7. TREATMENT OF ULCER GASTRODUODENAL BLEEDINGS: CURRENT STATE OF THE PROBLEM (A LITERATURE REVIEW

    O. N. Antonov

    2014-01-01

    Full Text Available ABSTRACT. The problem of ulcer gastro-duodenal bleeding therapy is one of the most essential in urgent surgery. The bleeding is the most serious complication of peptic ulcer desease. It is observed in 15– 20% cases when patients have peptic ulcer diagnosis determined. In general the issues of bleeding therapy in gastroduodenal sphere are surveyed imperfectly. Some patulous endoscopic hemostasis methods don’t fully meet safety and confidence reqirements that preserves high level of general and post-operational lethality in our country and in the rest of the world. 

  8. Effects of waves and currents on the siltation problem of Damietta harbour, Nile Delta coast, Egypt

    ABO BAKER.I. ABO ZED

    2007-12-01

    Full Text Available This study evaluates the effect of prevailing dynamic factors on the sedimentation process in Damietta Harbour along the Nile delta coast of Egypt. The monitoring program spanned the period between 1978 and 1999 and included measurements of waves, currents and bathymetric profiles. The evaluation was based on determination of erosion and accretion rates, current regime, sediment transport, wave characteristics and wave refraction. Results revealed that the predominant wave direction from N-NW sector (86 % throughout the year is responsible for generation of a longshore eastward current. Less frequent waves from the N-NE sector generate an opposing longshore westward current. The refraction pattern for the prevailing wave direction indicates that the harbour and its navigation channel are located within a divergence of wave orthogonal and in an accretion sediment sink area. The annual net rate of littoral drift on the western side of the harbour is about 1.43 * 105 m3 (accretion, while the annual net rate of littoral drift on the eastern side is about 2.54 * 105 m3 (erosion. Currents fluctuate tremendously in speed and direction, especially during the winter months. Hence, sediment transport takes place in offshore, eastward, and onshore directions. Progressive vector diagrams show that the largest near bottom offshore, onshore and easterly net drift occurs during summer, spring and winter respectively. The onshore sediment transport generated during spring and summer plays an important role in the redistribution of eroded sediments during the winter. The overall study of dynamic factors indicated that the harbour site is characterized by eastern, western, offshore and onshore sediment movements. Therefore, the north-south orientation of the navigation channel, with its depth greater than the surrounding area, interrupts sediment drift from different directions and reduces the current speed. Consequently, the sediments sink within the navigation

  9. [Problems of work world and its impact on health. Current financial crisis].

    Tomasina, Fernando

    2012-06-01

    Health and work are complex processes. Besides, they are multiple considering the forms they take. These two processes are linked to each other and they are influenced by each other. According to this, it is possible to establish that work world is extremely complex and heterogeneous. In this world, "old" or traditional risks coexist with "modern risks", derived from the new models of work organization and the incorporation of new technologies. Unemployment, work relationships precariousness and work risks outsourcing are results of neoliberal strategies. Some negative results of health-sickness process derived from transformation in work world and current global economic crisis have been noticed in current work conditions. Finally, the need for reconstructing policies focusing on this situation derived from work world is suggested.

  10. Problems of software financial resources agrarian sector in the current economic conditions of management

    Grischuk Nadiya Viktorivna

    2016-12-01

    Full Text Available Research of financial science on questions providing of financial resources does not exhaust and needs a further study that acquires new descriptions and vectors of development constantly, what costing illuminations in the conditions of present time. Research of the state of provision of financial resources agrarian to the sector of economy with allocating of main segment – loan and attracted financial resources, today topically. In the article the essence funds are considered sources of agricultural enterprises financial resources and problems associated with the formation and use of financial resources in the modern world. Also the problems arising in improving the process of raising funds agricultural enterprises. Revealed that an effective tool to attract financial resources is the issue of convertible bonds and the introduction of agricultural receipts. It is well-proven that in the conditions of unstable environment forward development of the system of agrarian relations must be carried out on the basis of the government programs, and normatively-legal adjusting that take into account not only the existent state of affairs at the market of agroindustrial products but also economic provision of enterprises national agrarian to the sector.

  11. Current treatment of chronic hepatitis C in China: Dilemma and potential problems.

    Han, Qun-Ying; Liu, Zheng-Wen

    2016-05-21

    Major advances have been made in the treatment of chronic hepatitis C virus (HCV) infection with the advent of direct-acting antiviral agents (DAAs). China has the most cases of HCV infection worldwide, but none of the DAAs has been approved in mainland China so far, and interferon (IFN)-α-based treatment remains the standard of care. HCV patients without response or with contraindications to IFN-based therapy have no alternative options. However, many patients buy DAAs, especially the generic forms of sofosbuvir, from other countries or areas. Under these circumstances, the use of these drugs may cause many predictable and unpredictable problems in ethics, law and medical practice. Given the obstacles of legal accessibility to DAAs and the potential problems of obtaining and using DAAs in China, the early launching of the DAAs in China or the legalization of buying drugs from areas outside China and using these drugs in China is an urgent issue and needs to be dealt with as soon as possible, in the interest of the patients.

  12. [Current issues, problems and prospects of tension-free hernioplasty (review)].

    2014-01-01

    In the present study there are discussed modern methods of the tension free hernioplastics, the complications associated with them and technical difficulties, up-to-date views and the perspectives of the issue development in terms of avoiding infectious complications, positioning of implants and their fixation. Hernia is one of the widespread surgical pathologies as it is found in 4% of the population and its share among the inpatient surgical diseases is about 18-30%. Consequently annually up to 20-21 mln hernioplasties are carried out worldwide. Despite of many years of experience in the field of hernia surgical treatment there still exist many unsolved problems such as safe closure of defects of abdominal cavity wall. Up to 200 methods of hernioplastics, various implantations and application of synthetic materials refer to lack of the optimal surgical strategy. In modern herniology priorities are given to tension free plastics. The merge of the synthetic implants and "tension free hernioplastics" concepts enabled sharp reduction of the side effects list, making it possible to perform successful surgeries in that contingent whose treatment by the method of tissue-plasty was related with high risk of lethality. Large scale introduction of tension free hernioplastics caused intensification of the associated problems such as migration, dissection and shortening of the net.

  13. [Current situations and problems of quality control for medical imaging display systems].

    Shibutani, Takayuki; Setojima, Tsuyoshi; Ueda, Katsumi; Takada, Katsumi; Okuno, Teiichi; Onoguchi, Masahisa; Nakajima, Tadashi; Fujisawa, Ichiro

    2015-04-01

    Diagnostic imaging has been shifted rapidly from film to monitor diagnostic. Consequently, Japan medical imaging and radiological systems industries association (JIRA) have recommended methods of quality control (QC) for medical imaging display systems. However, in spite of its need by majority of people, executing rate is low. The purpose of this study was to validate the problem including check items about QC for medical imaging display systems. We performed acceptance test of medical imaging display monitors based on Japanese engineering standards of radiological apparatus (JESRA) X-0093*A-2005 to 2009, and performed constancy test based on JESRA X-0093*A-2010 from 2010 to 2012. Furthermore, we investigated the cause of trouble and repaired number. Medical imaging display monitors had 23 inappropriate monitors about visual estimation, and all these monitors were not criteria of JESRA about luminance uniformity. Max luminance was significantly lower year-by-year about measurement estimation, and the 29 monitors did not meet the criteria of JESRA about luminance deviation. Repaired number of medical imaging display monitors had 25, and the cause was failure liquid crystal panel. We suggested the problems about medical imaging display systems.

  14. Finite element circuit theory of the numerical code EDDYMULT for solving eddy current problems in a multi-torus system

    Nakamura, Yukiharu; Ozeki, Takahisa

    1986-07-01

    The finite element circuit theory is extended to the general eddy current problem in a multi-torus system, which consists of various torus conductors and axisymmetric coil systems. The numerical procedures are devised to avoid practical restrictions of computer storage and computing time, that is, the reduction technique of eddy current eigen modes to save storage and the introduction of shape function into the double area integral of mode coupling to save time. The numerical code EDDYMULT based on the theory is developed to use in designing tokamak device from the viewpoints of the evaluation of electromagnetic loading on the device components and the control analysis of tokamak equilibrium. (author)

  15. CURRENT PROBLEMS OF DIAGNOSIS AND TREATMENT OF MILD COGNITIVE IMPAIRMENTS IN CHILDREN

    G.A. Karkashadze

    2011-01-01

    Full Text Available In practical pediatrics specialists paid wrongly little attention to identification and treatment of cognitive disorders in children. At the same time it is difficult to overestimate the influence of cognitive functions on the formation of human personality and social maladjustment in this part of population. The paper is devoted to the diagnosis and treatment of cognitive impairments. In addition, the classification of this pathology, highlighting aetiopathogenetic factors, prognosis are showed. One of the important problems of early revealing of cognitive impairments and appropriate management of children with this pathology according to the authors opinion are the following: the deficiency of educational programs for training specialists in neurology, lack of knowledge concerning the possibilities of psychological-pedagogical correction, inefficient system of neurological techniques for primary care. Key words: cognitive function, mild cognitive impairment, classification, diagnosis, treatment, prognosis, social maladjustment, psychopedagogical support, children. (Pediatric Pharmacology. — 2011; 8 (5: 37–41.

  16. Presymplectic current and the inverse problem of the calculus of variations

    Khavkine, Igor

    2013-11-01

    The inverse problem of the calculus of variations asks whether a given system of partial differential equations (PDEs) admits a variational formulation. We show that the existence of a presymplectic form in the variational bicomplex, when horizontally closed on solutions, allows us to construct a variational formulation for a subsystem of the given PDE. No constraints on the differential order or number of dependent or independent variables are assumed. The proof follows a recent observation of Bridges, Hydon, and Lawson [Math. Proc. Cambridge Philos. Soc. 148(01), 159-178 (2010)] and generalizes an older result of Henneaux [Ann. Phys. 140(1), 45-64 (1982)] from ordinary differential equations (ODEs) to PDEs. Uniqueness of the variational formulation is also discussed.

  17. Presymplectic current and the inverse problem of the calculus of variations

    Khavkine, Igor, E-mail: i.khavkine@uu.nl [Institute for Theoretical Physics, Utrecht, Leuvenlaan 4, NL-3584 CE Utrecht (Netherlands)

    2013-11-15

    The inverse problem of the calculus of variations asks whether a given system of partial differential equations (PDEs) admits a variational formulation. We show that the existence of a presymplectic form in the variational bicomplex, when horizontally closed on solutions, allows us to construct a variational formulation for a subsystem of the given PDE. No constraints on the differential order or number of dependent or independent variables are assumed. The proof follows a recent observation of Bridges, Hydon, and Lawson [Math. Proc. Cambridge Philos. Soc. 148(01), 159–178 (2010)] and generalizes an older result of Henneaux [Ann. Phys. 140(1), 45–64 (1982)] from ordinary differential equations (ODEs) to PDEs. Uniqueness of the variational formulation is also discussed.

  18. Symposium on Decoherence and No-Signalling : Current Interpretational Problems of Quantum Theory

    Wüthrich, Adrian; New vistas on old problems : recent approaches to the foundations of quantum mechanics

    2017-01-01

    Quantum theory has been a subject of interpretational debates ever since its inception. The Einstein-Podolsky-Rosen paradox, the empirical violation of Bell's inequalities, and recent activities to exploit quantum entanglement for technological innovation only exacerbate a long-standing philosophical debate. Despite no-signaling theorems and theories of decoherence, deep- rooted conflicts between special relativistic principles and observed quantum correlations as well as between definite measurement outcomes and quantum theoretical superpositions persist. This collection of papers, first presented at an international symposium at the University of Bern in 2011, highlights some recent approaches to the old problems of a philosophy of quantum mechanics. The authors address the issues from a variety of perspectives, ranging from variations of causal theory and system theoretic interpretations of the observer to an empirical test of whether entanglement itself can be entangled. The essays demonstrate that the di...

  19. Single Phase Current-Source Active Rectifier for Traction: Control System Design and Practical Problems

    Jan Michalik

    2006-01-01

    Full Text Available This research has been motivated by industrial demand for single phase current-source active rectifier dedicated for reconstruction of older types of dc machine locomotives. This paper presents converters control structure design and simulations. The proposed converter control is based on the mathematical model and due to possible interaction with railway signaling and required low switching frequency employs synchronous PWM. The simulation results are verified by experimental tests performed on designed laboratory prototype of power of 7kVA

  20. Cognitive-behavior therapy for problem gambling: a critique of current treatments and proposed new unified approach.

    Tolchard, Barry

    2017-06-01

    There is evidence supporting the use of cognitive-behavioral therapy (CBT) in the treatment of problem gambling. Despite this, little is known about how CBT works and which particular approach is most effective. This paper aims to synthesize the evidence for current CBT and propose a more unified approach to treatment. A literature review and narrative synthesis of the current research evidence of CBT for the treatment of problem gambling was conducted, focusing on the underlying mechanisms within the treatment approach. Several CBT approaches were critiqued. These can be divided into forms of exposure therapy (including aversion techniques, systematic desensitization and other behavioral experiments) those focusing on cognitive restructuring techniques (such as reinforcement of nongambling activity, use of diaries, motivational enhancement and audio-playback techniques and third wave techniques including mindfulness. Findings, in relation to the treatment actions, from this synthesis are reported. The debate surrounding the treatment of problem gambling has been conducted as an either/or rather than a both/and discourse. This paper proposes a new, unified approach to the treatment of problem gambling that incorporates the best elements of both exposure and cognitive restructuring techniques, alongside the use of techniques borrowed from mindfulness and other CBT approaches.

  1. [Reimbursement of intensive care services in the German DRG system : Current problems and possible solutions].

    Riessen, R; Hermes, C; Bodmann, K-F; Janssens, U; Markewitz, A

    2018-02-01

    The reimbursement of intensive care and nursing services in the German health system is based on the diagnosis-related groups (G-DRG) system. Due to the lack of a central hospital planning, the G‑DRG system has become the most important influence on the development of the German health system. Compared to other countries, intensive care in Germany is characterized by a high number of intensive care beds, a low nurse-to-patient ratio, no official definition of the level of care, and a minimal available data set from intensive care units (ICUs). Under the given circumstances, a shortage of qualified intensive care nurses and physicians is currently the largest threat for intensive care in Germany. To address these deficiencies, we suggest the following measures: (1) Integration of ICUs into the levels of care which are currently developed for emergency centers at hospitals. (2) Mandatory collection of structured data sets from all ICUs including quality criteria. (3) A reform of intensive care and nursing reimbursement under consideration of adequate staffing in the individual ICU. (4) Actions to improve ICU staffing and qualification.

  2. US patent interferences vs. international first-to-file patent systems, and current GATT problems

    Parkhurst, R.W.; Serbinowski, P.A.

    1991-01-01

    Simultaneous superconductivity research activities by different entities have resulted in numerous US patent applications, some of which may claim identical inventions and thus likely will be involved in interference proceedings in the US Patent and Trademark Office to determine which inventors are entitled to priority of invention and the resulting US patent. The determination in an interference proceeding of what inventors were the first-to-invent a patentable invention is contrasted with the patent systems in the rest of the world where the first inventor to file his patent application automatically gains priority. This issue and other aspects of US patent law are the subjects of criticism of US patent law and practice in the current Uruguay round of talks on the General Agreement on Trade and Tariffs (GATT). Interesting aspects of each of these subjects will be discussed

  3. Characterisation of plastic packaging waste for recycling: problems related to current approaches

    Götze, Ramona; Astrup, Thomas Fruergaard

    2013-01-01

    criteria of recycling processes. A lack of information in current waste characterisation practise on polymer resin composition, black coloured material content and the influence of surface adherent material on physico-chemical characteristics of plastic packaging waste were identified. These shortcomings...... were addressed by a resin type-based sorting analysis and a washing test for plastic packaging material from Danish household waste. Preliminary results show that, for a quarter of the hand sorted material, no resin type could be identified and that Polypropylene and Polyethylene terephthalate were...... the dominating resin types in plastic packaging. The suggested washing procedure caused a decrease of 70% of the ash content of the plastic material. The analysed metals and nutrients were reduced by up to 24%...

  4. Skin, eye, and testis: current exposure problems and recent advances in radiobiology

    Charles, M.W.

    1986-01-01

    Three organs, the skin, eye and testis are potentially at risk from poorly penetrating radiations such as beta particles or low energy X-Rays. They may be preferentially irradiated in fields with steep depth - dose gradients and thereby dictate radiological protection procedures. Since there is not a wide margin of safety in the annual permissible dose limits for these organs it is important to have clearly defensible methods of dose assessment. This requires both an adequate understanding of the radiobiology of these organs and the availability of experimental techniques for measuring doses at various depths near the surface of the body. This paper reviews the current state of knowledge in this field, drawing partly on information from two recent CEC workshops on the 'Dosimetry of Beta Particles and Low Energy X-Rays' and 'Radiation Damage to the Skin'. It is concluded that protection criteria for the limitation of skin dose are in need of revision. (author)

  5. Chloramphenicol Derivatives as Antibacterial and Anticancer Agents: Historic Problems and Current Solutions

    George P. Dinos

    2016-06-01

    Full Text Available Chloramphenicol (CAM is the D-threo isomer of a small molecule, consisting of a p-nitrobenzene ring connected to a dichloroacetyl tail through a 2-amino-1,3-propanediol moiety. CAM displays a broad-spectrum bacteriostatic activity by specifically inhibiting the bacterial protein synthesis. In certain but important cases, it also exhibits bactericidal activity, namely against the three most common causes of meningitis, Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis. Resistance to CAM has been frequently reported and ascribed to a variety of mechanisms. However, the most important concerns that limit its clinical utility relate to side effects such as neurotoxicity and hematologic disorders. In this review, we present previous and current efforts to synthesize CAM derivatives with improved pharmacological properties. In addition, we highlight potentially broader roles of these derivatives in investigating the plasticity of the ribosomal catalytic center, the main target of CAM.

  6. The longitudinal space charge problem in the high current linear proton accelerators

    Lustfeld, H.

    1984-01-01

    In a linear proton accelerator peak currents of 200 mA lead to high space charge densities and the resultant space charge forces reduce the effective focussing considerably. In particular the longitudinal focussing is affected. A new concept based on linear theory is proposed that restricts the influence of the space charge forces on the longitudinal focussing by increasing a, the mean transverse bunch radius, as a proportional(βγ)sup(3/8). This concept is compared with other concepts for the Alvarez (1 MeV - 100 MeV) and for the high energy part (100 MeV - 1100 MeV) of the SNQ linear accelerator. (orig.)

  7. Roman Criminal Law. Contributions to Current Problems in Connection with “Crimes against Public Administration”

    Fabio Espitia Garzón

    2016-12-01

    Full Text Available The secular and detailed study of Roman Private Law institutions has, for centuries, diverted the attention to institutions pertaining to the Public Law sphere. Such studies were a consequence of the triumph of bourgeois ideas from the Enlightenment, which were structured on a set of principles (separation of powers, the principle of legality both considered absolute truths, even though today they seem more like myths. This understanding shifted during the second half of the twentieth century, when scholars of Roman Law began to more comprehensively analyze Rome’s constitutional institutions as well as its criminal repression. This paper begins with a review of some of the most important works and articles produced since the fifties until present day about the so called ‘general ’and ´special’ Criminal Law, and the Law of Criminal Procedure, it then focuses on how useful those texts are in order to solve actual problems, taking as an example the subject of crimes against public administration, given the actual need to pursue the assets obtained from such activities, despite the perpetrator’s death, which means going beyond the principle of the individual nature of penalties.

  8. ETHICAL REVIEW OF BIOMEDICAL RESEARCH IN BELARUS: CURRENT STATUS, PROBLEMS AND PERSPECTIVES.

    Famenka, Andrei

    2011-04-01

    The paper provides description of the system of ethical review for biomedical research in Belarus, with special emphasis on its historical background, legal and regulatory framework, structure and functioning. It concludes that the situation with research ethics in Belarus corresponds to the tendency of bureaucratic approach to establishment of systems of ethical review for biomedical research, observed in a number of countries of Central and Eastern Europe. Different social, economical and political factors of transition have major impact on capacities of the Belarusian RECs to ensure adequate protection of human subjects. Among the main problems identified are non-equivalent stringency of ethical review for different types of biomedical research; lack of independence, multidisciplinarity, pluralism and lay representation experienced by RECs; low level of research ethics education and transparency of RECs activities. Recommendations are made to raise the issue of research ethics on the national agenda in order to develop and maintain the research ethics system capable to effectively protect research participants and promote ethical conduct in research.

  9. Wetland Planning: Current Problems and Environmental Management Proposals at Supra-Municipal Scale (Spanish Mediterranean Coast

    María-Teresa Sebastiá-Frasquet

    2014-03-01

    Full Text Available The policies that define the use and management of wetlands in Spain have undergone tremendous changes in recent decades. During the period of 1950–1980, Land Reform Plans promoted filling and draining of these areas for agricultural use. In 1986, with the incorporation of Spain to the European Union (EU, there was a sudden change of direction in these policies, which, thereafter, pursued restoring and protecting these ecosystems. This change, combined with increasing urban development and infrastructure pressures (e.g., roads, golf courses, etc., creates a conflict of uses which complicates the management of these ecosystems by local governments. This study analyzes the effectiveness of policies and management tools of important coastal wetlands at the local scale in the Valencian Community (Western Mediterranean Sea using a strengths-weaknesses-opportunities-threats (SWOT methodology. A supra-municipal model of environmental planning is proposed to enable consistent management at a regional scale. This model enhances local government’s effectiveness and it can be applied in other areas with similar problems.

  10. Observations on the current status of Orobanche and Striga problems worldwide.

    Parker, Chris

    2009-05-01

    Species of Orobanche and Striga are among the most damaging parasitic weed species worldwide, but there are few reliable statistics on the full extent of the economic losses they cause. The distribution, host range and economic importance of the major species of Orobanche and Striga are briefly summarised. A review of literature over the period since 1991 suggests that many million hectares are infested and that the losses amount to $ US billions annually. Unfortunately there are almost no fully reliable figures on which to base these figures precisely. Meanwhile, there is little evidence of any significant change in intensity, range or losses caused over this period. Any reduction in the importance of these damaging weeds is sporadic, and alleviation of the problems is mostly localised. Furthermore, while the importance of Orobanche species may be broadly static, Striga species on cereals continue to become more serious in many countries owing to continued loss of soil fertility. It is suggested that new techniques may be needed for measurement of the extent of losses caused by these genera and their economic impact. There is continued urgency to develop control measures appropriate to the farming systems involved, and to reduce the risk of spread of both groups of parasite to new areas.

  11. Food safety and ecologization: practical solutions to problems at the regional level in current economic conditions

    Lysochenko Alla, A.

    2015-03-01

    Full Text Available Ensuring food security and greening both at the level of the country, and at the level of regions are main objectives of modern agroeconomic policy. The state support creates favorable conditions for dynamic development of agrarian and industrial complex, raises investment opportunities and competitiveness of agricultural producers. A realization of the actions directed on assistance to the enterprises making import-substituting production of the regional agro-industrial complex is actual in modern economic conditions. The solution of this problem consists of investment projects implementation and production expansion of the operating enterprises. Considering new economic conditions, the ensuring financial stability of agricultural producers, availability of the food to needy segments of the population, production of valeologically safe food, and also increase efficiency of use of natural resources and conditions along with preservation of quality of environment at the local, regional and global levels are particularly acute challenges. State regulation of development of an agrofood complex of Russia remains a necessary condition for its reproduction functioning, and the social and economic policy has to provide economic availability of the food to all groups of the population that causes need of standard and legal fixing of mechanisms offood security achievement at the regional level.

  12. [Mixed affective states in the juvenile age (historical aspects, current state of the problem, psychopathology)].

    Kopeĭko, G I

    2011-01-01

    The author analyzed the problem in historical, diagnostic and psychopathological aspects and presented the results of his own study. The aim was to study the structure and dynamics of endogenous juvenile mixed states in order to work out the psychopathological typology and to clarify the criteria of diagnosis, differential treatment and clinical-social prognosis. The study included 174 patients, 118 men and 56 women, aged from 17 to 25 years (mean age 20, 4 years). Depressive states were found in 65%, mania in 16% and mixed in 19% of patients. The clinical differentiation of mixed states was carried out basing on the dominating pole of affective disorders and the following types were singled out and described: mania type (dysphoria-like mania)--34%, depressive type (association-driven depression)--38%; alternating type of mixed states--28%. The preference of the formation of alternating and atypical variants of mixed states in the juvenile age demonstrated in the study may reflect the pathogenetic and pathoplastic effect of biological features characteristic of this age--lability and polymorphism of clinical presentations as well as immaturity of emotional and cognitive spheres.

  13. Current state of the effectiveness of problem-based learning in prosthodontics: a systematic review.

    Eslami, Ehsan; Bassir, Seyed Hossein; Sadr-Eshkevari, Pooyan

    2014-05-01

    The aim of this study was to systematically review the available literature on the effectiveness of problem-based learning (PBL) in prosthodontics. Both electronic and manual searches were performed by two reviewers. Of the 440 studies identified, ten met the inclusion criteria (Kappa=0.83). Various assessment tools such as standardized examinations (National Board Dental Examination and North East Regional Board of Dental Examiners exam) (22 percent), tutor evaluation (practical and examinations performance) (20 percent), curriculum time (20 percent) and number of units (10 percent), peer evaluation (10 percent), and self-evaluation (100 percent) were used in the included studies. Thirty percent of the studies adopted a control group for all measurements, 30 percent did for only some measurements, and the others lacked any control group. Although 30 percent of the studies implemented a hybrid PBL, the other studies did not mention the type of PBL. Based on the Effective Public Health Practice Project (EPHPP), all of the included studies were rated as being of weak quality. Heterogeneity across these studies in outcome variables, study designs, levels of PBL intervention, and study population limits any attempt to generalize the outcomes. The generally poor quality assessment outcomes warrant further studies on the effectiveness of PBL in prosthodontics education compared to a non-PBL curriculum.

  14. Temperature in non-equilibrium states: a review of open problems and current proposals

    Casas-Vazquez, J; Jou, D

    2003-01-01

    The conceptual problems arising in the definition and measurement of temperature in non-equilibrium states are discussed in this paper in situations where the local-equilibrium hypothesis is no longer satisfactory. This is a necessary and urgent discussion because of the increasing interest in thermodynamic theories beyond local equilibrium, in computer simulations, in non-linear statistical mechanics, in new experiments, and in technological applications of nanoscale systems and material sciences. First, we briefly review the concept of temperature from the perspectives of equilibrium thermodynamics and statistical mechanics. Afterwards, we explore which of the equilibrium concepts may be extrapolated beyond local equilibrium and which of them should be modified, then we review several attempts to define temperature in non-equilibrium situations from macroscopic and microscopic bases. A wide review of proposals is offered on effective non-equilibrium temperatures and their application to ideal and real gases, electromagnetic radiation, nuclear collisions, granular systems, glasses, sheared fluids, amorphous semiconductors and turbulent fluids. The consistency between the different relativistic transformation laws for temperature is discussed in the new light gained from this perspective. A wide bibliography is provided in order to foster further research in this field

  15. CURRENT TRENDS AND PROBLEMS OF DEVELOPMENT OF YOUTH TRAVEL IN RUSSIA ON THE EXAMPLE OF KRASNODAR REGION

    Daria V. Sidorova

    2017-01-01

    Full Text Available To consider tendencies and problems of development of youth travel in Russia in general and in Krasnodar region in particular, and also possible solutions of the revealed problems. Methods. The comparative and geographical method, statistical processing, population poll were applied. Results. Data on current trends of development of youth travel in Russia and in Krasnodar region are submitted and factors, constraining his full development are revealed. The description of the actions directed to promoting of this type of tourism in Krasnodar region is given. Recommendations about the solution of the problems existing in the sphere of youth travel of Krasnodar region are provided. Conclusions. In the modern world more and more popular is a youth travel. His popularity is caused by such qualities of youth as activity, aspiration to training and knowledge, the need for new feelings. Relevance of a research of this type of tourism is caused by the increasing youth share in tourist streams, and also insufficiency of methodical developments of a problem of complex development of system of youth travel. Krasnodar region is the most perspective from the point of view of development of all types of tourism, including youth. The region has a unique environment, modern infrastructure, the developed tourist and recreational complex. At the same time during the research a number of the problems constraining development of this type of tourism is revealed.

  16. Structural, Functional, and Metabolic Brain Markers Differentiate Collision versus Contact and Non-Contact Athletes.

    Churchill, Nathan W; Hutchison, Michael G; Di Battista, Alex P; Graham, Simon J; Schweizer, Tom A

    2017-01-01

    There is growing concern about how participation in contact sports affects the brain. Retrospective evidence suggests that contact sports are associated with long-term negative health outcomes. However, much of the research to date has focused on former athletes with significant health problems. Less is known about the health of current athletes in contact and collision sports who have not reported significant medical issues. In this cross-sectional study, advanced magnetic resonance imaging (MRI) was used to evaluate multiple aspects of brain physiology in three groups of athletes participating in non-contact sports ( N  = 20), contact sports ( N  = 22), and collision sports ( N  = 23). Diffusion tensor imaging was used to assess white matter microstructure based on measures of fractional anisotropy (FA) and mean diffusivity (MD); resting-state functional MRI was used to evaluate global functional connectivity; single-voxel spectroscopy was used to compare ratios of neural metabolites, including N -acetyl aspartate (NAA), creatine (Cr), choline, and myo-inositol. Multivariate analysis revealed structural, functional, and metabolic measures that reliably differentiated between sport groups. The collision group had significantly elevated FA and reduced MD in white matter, compared to both contact and non-contact groups. In contrast, the collision group showed significant reductions in functional connectivity and the NAA/Cr metabolite ratio, relative to only the non-contact group, while the contact group overlapped with both non-contact and collision groups. For brain regions associated with contact sport participation, athletes with a history of concussion also showed greater alterations in FA and functional connectivity, indicating a potential cumulative effect of both contact exposure and concussion history on brain physiology. These findings indicate persistent differences in brain physiology for athletes participating in contact and collision sports

  17. Current problems of raw fish material processing while manufacturing dried products

    Yashonkov A. A.

    2017-09-01

    Full Text Available The substantiation for using techniques of fish raw material canning has been presented, raw fish being caught or farmed in aquaculture. The main problems in raw fish canning have been reviewed, including significant reduction in thermolabile vitamins in the ultimate product as compared with the raw material due to the thermal processing. Promising canning technique – vacuum drying – has been proposed. This technique makes possible to reduce the temperature of thermal processing down to 50…55 °С and significantly enlarge preservation of thermolabile vitamins from the raw fish. Sampling of raw materials, semi-finished products, finished products, including preparation for analysis has been conducted by standard methods. Disadvantages of this way have been found, it is low energy efficiency of the process. The way to intensify the vacuum drying of aquatic organisms has been proposed based on the method of preliminary pore-forming due to augmenting the area of moisture evaporation. The design of the pilot plant has been proposed in order to research the process of pore forming and vacuum drying. Target species for processing have been suggested. They are as follows: Azov goby (fillet for food products and Black Sea sprat for feeds. The recipes of the feed mixture for granulated floating food for trout have been developed. The results of the first series of the pilot research have been provided. The experiments have proved that preliminary pore forming immediately before vacuum drying makes possible to enlarge the surface area of moisture evaporation by 15…25 %. By processing photomicrographs of sections by means of a special software the authors have got the results demonstrating that when manufacturing dried products by pore forming and drying under pressure 10 kPa the pore take 35...38 % of the inner volume of the product and with drying under pressure 10 kPa – only 18...21 %, and when drying under the atmospheric pressure – 11...13 %.

  18. Łagodne zaburzenia poznawcze – aktualny problem geriatryczny = Mild cognitive impairment – current geriatric issue

    Oliwia Beck

    2016-04-01

      Streszczenie Artykuł przedstawia aktualny stan wiedzy dotyczący łagodnych zaburzeń poznawczych (Mild Cognitive Impairment, MCI. Termin ten, początkowo uważany za stan przejściowy pomiędzy prawidłowym funkcjonowaniem poznawczym a objawami choroby Alzheimera (Alzheimer’s disease, AD, obecnie oznacza heterogenną grupę widocznych i obiektywnych deficytów kognitywnych u pacjentów bez rozpoznanego otępienia. Deficyty te, choć zauważalne zarówno dla osób nimi dotkniętych, jak i ich otoczenia, są na tyle nieznaczne, że nie wpływają na podstawowe czynności życia codziennego i zdolność do samodzielnej egzystencji. Rozpowszechnienie MCI szacuje się na 15 – 30% wśród osób powyżej 60 roku życia; rośnie ono wraz z wiekiem. Łagodnym zaburzeniom poznawczym – zwłaszcza ich postaci amnestycznej - przypisuje się podwyższone ryzyko rozwinięcia się otępienia, wynoszące 10 – 15% rocznie (przy 1 – 2% dla populacji ogólnej. Z tego powodu identyfikacja osób z MCI jest obecnie najważniejszą strategią opóźniania postępu otępień i zapobiegania im.   Słowa kluczowe: łagodne zaburzenia poznawcze, funkcjonowanie poznawcze, wiek podeszły, otępienie       Summary The article describes current state of knowledge on Mild Cognitive Impairment (MCI. The term, initially considered a transitional state between normal cognitive aging and mild Alzheimer’s disease (AD, currently covers heterogenous group of noticeable and objective cognitive deficits in patients without the diagnosis of dementia. These deficits, although apparent for both afflicted persons and their environment, do not interfere substantially with basic activities of daily living nor result in inability to live independently. The prevalence of MCI is estimated between 15 and 30% in individuals over 60 years old. Subjects with MCI constitute a high risk group because they develop dementia at a rate of 10% to 15% per year compared with 1% to 2% per year in the general

  19. Advanced 3-dimensional electron kinetic calculations for the current drive problem in magnetically confined thermonuclear plasmas

    Peysson, Y.; Decker, J.; Bers, A.; Ram, A.; Harvey, R.

    2004-01-01

    Accurate and fast electron kinetic calculations is a challenging issue for realistic simulations of thermonuclear tokamak plasmas. Relativistic corrections and electron trajectory effects must be fully taken into account for high temperature burning plasmas, while codes should also consistently describe wave-particle resonant interactions in presence of locally large gradients close to internal transport barrier. In that case, neoclassical effects may come into play and self-consistent evaluation of both the radio-frequency and bootstrap currents must be performed. In addition, a complex interplay between momentum and radial electron dynamics may take place, in presence of a possible energy dependent radial transport. Besides the physics needs, there are considerable numerical issues to solve, in order to reduce computer time consumption and memory requirements at an acceptable level, so that kinetic calculations may be valuably incorporated in a chain of codes which determines plasma equilibrium and wave propagation. So far, fully implicit 3-dimensional calculations based on a finite difference scheme and an incomplete L and U matrices factorization have been found to be so most effective method to reach this goal. A review of the present status in this active field of physics is presented, with an emphasis on possible future improvements. (authors)

  20. Some current problems in atmospheric ozone chemistry; role of chemical kinetics

    Cox, R.A.

    1987-03-01

    A review is given on selected aspects of the reaction mechanisms of current interest in the chemistry of atmospheric ozone. Atmospheric ozone is produced and removed by a complex series of elementary gas-phase photochemical reactions involving O/sub x/, HO/sub x/, NO/sub x/, CIO/sub x/ and hydrocarbon species. At the present time there is a good knowledge of the basic processes involved in ozone chemistry in the stratosphere and the troposphere and the kinetics of most of the key reactions are well defined. There are a number of difficulties in the theoretical descriptions of observed ozone behaviour which may be due to uncertainties in the chemistry. Examples are the failure to predict present day ozone in the photochemically controlled region above 35 Km altitude and the large reductions in the ozone column in the Antartic Spring which has been observed in recent years. In the troposphere there is growing evidence that ozone and other trace gases have changed appreciably from pre-industrial concentrations, due to chemical reactions involving man-made pollutants. Quantitative investigation of the mechanisms by which these changes may occur requires a sound laboratory kinetics data base.

  1. Allergic Contact Dermatitis

    Meltem Önder

    2009-03-01

    Full Text Available Allergic contact dermatitis is the delayed type hypersensitivity reaction to exogenous agents. Allergic contact dermatitis may clinically present acutely after allergen exposure and initial sensitization in a previously sensitized individual. Acute phase is characterized by erythematous, scaly plaques. In severe cases vesiculation and bullae in exposed areas are very characteristic. Repeated or continuous exposure of sensitized individual with allergen result in chronic dermatitis. Lichenification, erythematous plaques, hyperkeratosis and fissuring may develop in chronic patients. Allergic contact dermatitis is very common dermatologic problem in dermatology daily practice. A diagnosis of contact dermatitis requires the careful consideration of patient history, physical examination and patch testing. The knowledge of the clinical features of the skin reactions to various contactans is important to make a correct diagnosis of contact dermatitis. It can be seen in every age, in children textile product, accessories and touch products are common allergens, while in adults allergic contact dermatitis may be related with topical medicaments. The contact pattern of contact dermatitis depends on fashion and local traditions as well. The localization of allergic reaction should be evaluated and patients’ occupation and hobbies should be asked. The purpose of this review is to introduce to our collaques up dated allergic contact dermatitis literatures both in Turkey and in the World.

  2. Öğretmenlerin Güncel Sorunları Teachers In The Current Problems

    İbrahim HABACI

    2013-07-01

    Full Text Available Education has a significant role in the development of a country.As it is widely accepted , Countries investing in education have been developing fast in all aspects of life . There are many factors affecting education, but they are not effective as much as a teacher . Without teacher , other factors can’t be significant enough as much as they are supposed to be . He is the teacher who trains doctor , scientist , politician , architect , worker , officer and so on . Teachers are not only the insructors working in school to make students be the future’s professionals but also they are the pedagogues who are trying to be the best real role models for their students with their thoughts , life styles and attitudes and above all they have a crucial role in the formation and development of their student’s characters during their school lives . As teachers are devoloping and forming the members of the population ,they are also developing and forming the population they are living in . The better new generations are trained , the wealthier and happier population we will have . To be able to do all these things mentioned above , of course , there are some conditions to be done completely . In return a teacher should have strong self - confidence , good field information , good pedagogical formation and in addition to these s/he should be aware of the importance of the profession s/he will do . If the teachers are trained well and their working conditions are developed in accordance with the today’s needs , quality of the education can be increased . This also opens the ways taking us to a developed , peaceful and wealthy country .The aim of this study is to determine the teachers’ problems and put them forward .This study has a great significance as it can be helpful and make a contribution to solution of teachers’ problems . Bir ülkenin gelişmesinde eğitimin payı büyüktür. Eğitime yatırım yapan ülkeler her açıdan geli

  3. The current status and problems confronted in delivering precision medicine in Japan and Europe.

    Bando, Hideaki

    Precision medicine has been defined as "a predictive, preventive, personalized, and participatory health care service delivery model." Today, developments in next-generation sequencing and information technology have made precision medicine possible, with massive amounts of genetic, "omics," clinical, environmental, and lifestyle data now available. Unfortunately, differences in governmental support and health care regulations have resulted in heterogeneous progress among countries. In Japan, for example, precision cancer screening and treatments are increasingly being promoted, with collaboration among research, governmental, and pharmaceutical agencies taking place in the nationwide SCRUM-Japan cancer genome screening project. The missions of SCRUM-Japan are to deliver the most appropriate therapeutic agents to the most suitable patients, and to play key roles in the development of multiplex diagnostic products and new indications for targeted therapy. Starting in February 2015 and ending in March 2017, the aim is to enroll 4750 patients with cancer (2350 patients with lung cancer and 2400 patients with gastrointestinal tract cancer). Compared with other developed countries, investments in scientific innovation for biomedical and omics research are matched or even surpassed in Europe, but regulatory differences in each countries are a major hurdle to rapid implementation. Although market approval for pharmaceuticals is centralized through the European Medicines Agency, access to health care is heterogeneously regulated at national levels, which undermines the consistency, comparability, and quality of precision medicine for cancer patients in Europe. In this review, we focus on the current progress of precision medicine in Japan and Europe, and clarify the differences in progress and the hurdles faced moving forward. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Case studies: Application of SEA in provincial level expressway infrastructure network planning in China - Current existing problems

    Zhou Kaiyi; Sheate, William R.

    2011-01-01

    Since the Law of the People's Republic of China on Environmental Impact Assessment was enacted in 2003 and Huanfa 2004 No. 98 was released in 2004, Strategic Environmental Assessment (SEA) has been officially being implemented in the expressway infrastructure planning field in China. Through scrutinizing two SEA application cases of China's provincial level expressway infrastructure (PLEI) network plans, it is found that current SEA practice in expressway infrastructure planning field has a number of problems including: SEA practitioners do not fully understand the objective of SEA; its potential contributions to strategic planning and decision-making is extremely limited; the employed application procedure and prediction and assessment techniques are too simple to bring objective, unbiased and scientific results; and no alternative options are considered. All these problems directly lead to poor quality SEA and consequently weaken SEA's effectiveness.

  5. Contact materials for nanoelectronics

    Alshareef, Husam N.

    2011-02-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena that modify the expected device performance. These reactions have become more challenging and more difficult to control as new materials have been introduced and as device sizes have entered the deep nanoscale. To provide an overview of this field of inquiry, this issue of MRS Bulletin includes articles on gate and contact materials for Si-based devices, junction contact materials for Si-based devices, and contact materials for alternate channel substrates (Ge and III-V), nanodevices. © 2011 Materials Research Society.

  6. An analytic solution to the homogeneous EIT problem on the 2D disk and its application to estimation of electrode contact impedances

    Demidenko, Eugene

    2011-01-01

    An analytic solution of the potential distribution on a 2D homogeneous disk for electrical impedance tomography under the complete electrode model is expressed via an infinite system of linear equations. For the shunt electrode model with two electrodes, our solution coincides with the previously derived solution expressed via elliptic integral (Pidcock et al 1995 Physiol. Meas. 16 77–90). The Dirichlet-to-Neumann map is derived for statistical estimation via nonlinear least squares. The solution is validated in phantom experiments and applied for breast contact impedance estimation in vivo. Statistical hypothesis testing is used to test whether the contact impedances are the same across electrodes or all equal zero. Our solution can be especially useful for a rapid real-time test for bad surface contact in clinical setting

  7. Current Problems in Schooling

    Andrej Adam

    2014-06-01

    Full Text Available In this article, we try to analyze two things: (1 the characteristics of the neoliberal attack on school in general, in the age of “human capital”, and (2 what form this attack has acquired in our society. Today, one can see the subjugation of the school to economy in all developed capitalist countries, but if this subjugation is going on in some of the most developed countries, with unabated investment in education, then this attack is much more direct and raw in our society where government expects the subjugation of the school to the market while minimizing input into it. In both cases, it is a fact that this attack, which subordinates school to capital, could not have happened, or at least would have been less likely to occur, if it had not been accompanied by a new school discourse, to which teachers themselves contribute, either by remaining passive or by misunderstanding the contemporary school reality. The article mainly relies on the work of Christian Laval – L'École n'est pas une entreprise: Le néo-libéralisme à l'assaut de l'enseignement public.

  8. Allergic contact dermatitis: epidemiology, molecular mechanisms, in vitro methods and regulatory aspects : Current knowledge assembled at an international workshop at BfR, Germany

    Peiser, M; Tralau, T; Heidler, J

    2012-01-01

    potential contact allergens. However, the local lymph node assay (LLNA) presently remains the validated method of choice for hazard identification and characterisation. At the workshop the use of the LLNA for regulatory purposes and for quantitative risk assessment was also discussed....

  9. An elastic-plastic contact model for line contact structures

    Zhu, Haibin; Zhao, Yingtao; He, Zhifeng; Zhang, Ruinan; Ma, Shaopeng

    2018-06-01

    Although numerical simulation tools are now very powerful, the development of analytical models is very important for the prediction of the mechanical behaviour of line contact structures for deeply understanding contact problems and engineering applications. For the line contact structures widely used in the engineering field, few analytical models are available for predicting the mechanical behaviour when the structures deform plastically, as the classic Hertz's theory would be invalid. Thus, the present study proposed an elastic-plastic model for line contact structures based on the understanding of the yield mechanism. A mathematical expression describing the global relationship between load history and contact width evolution of line contact structures was obtained. The proposed model was verified through an actual line contact test and a corresponding numerical simulation. The results confirmed that this model can be used to accurately predict the elastic-plastic mechanical behaviour of a line contact structure.

  10. Analyzing the problems with the current adoption of IFRS in the companies among India, China, Germany, Russia and Kenya

    Robert Mosomi Ombati

    2018-01-01

    Full Text Available Accounting information provides past and current financial information of an economic unit for business managers, potential investors, and other interested parties. Internally generated accounting information helps business managers with planning, controlling, and making decisions referred to as managerial accounting information. However, if the companies, which have adopted International Financial Reporting Standards (IFRS globally, cannot generate the same information then the accounting practices need to be improved. For this purpose, the current study was performed with the objectives of measuring relationship between profitability and market capitalization and to analyze the challenges faced by listed firms of various countries in association with the implementation of IFRS. For this purpose, 15 companies were selected from 5 countries including India, China, Germany, Russia and Kenya. The secondary data regarding the correlation between profitability and market capitalization were analyzed to calculate the correlations. The primary data regarding the managers perception were analyzed with multiple regression method using SPSS-19 software to find out the company related variables, investors’ related variables and government agency related variables responsible for problems in the current adoption of IFRS.

  11. Impact of radioactivity on the environment: problems, state of current knowledge and approaches for identification of radioprotection criteria

    Brechignac, F.

    2001-01-01

    There is currently a revitalized concern about the potential impact of ionizing radiation on the environment that calls for the construction of a system ensuring an adequate radioprotection of the non-human biota and their associated biotopes. This paper first sets the context of the problem both, with respect to the general philosophy of environmental protection as a whole, but also with respect to the consideration of the environment achieved so far in the purpose of human radioprotection. The current accumulated knowledge on the effects of ionizing radiation to biota (fauna and flora) is then briefly reviewed, encompassing effects at individual and community/ecosystem level, situations of acute and chronic exposure to high and low doses, finally leading to the identification of the most critical gaps in scientific knowledge: effects of mixed low dose rates in chronic exposure to communities and ecosystems. The most significant current international efforts towards the identification of environmental radioprotection criteria and standards are finally presented along with some relevant national examples. (author)

  12. Efficient solution of 3D electromagnetic eddy-current problems within the finite volume framework of OpenFOAM

    Beckstein, Pascal; Galindo, Vladimir; Vukčević, Vuko

    2017-09-01

    Eddy-current problems occur in a wide range of industrial and metallurgical applications where conducting material is processed inductively. Motivated by realising coupled multi-physics simulations, we present a new method for the solution of such problems in the finite volume framework of foam-extend, an extended version of the very popular OpenFOAM software. The numerical procedure involves a semi-coupled multi-mesh approach to solve Maxwell's equations for non-magnetic materials by means of the Coulomb gauged magnetic vector potential A and the electric scalar potential ϕ. The concept is further extended on the basis of the impressed and reduced magnetic vector potential and its usage in accordance with Biot-Savart's law to achieve a very efficient overall modelling even for complex three-dimensional geometries. Moreover, we present a special discretisation scheme to account for possible discontinuities in the electrical conductivity. To complement our numerical method, an extensive validation is completing the paper, which provides insight into the behaviour and the potential of our approach.

  13. Current problems of the Bulgarian energy industry against the background of global short-term energy demand

    Batov, S.

    1999-01-01

    The energy demand during the next century due first of all to the expected growth of population necessitates more efficient technologies and huge investments. The production of nuclear energy requires higher safety as well as reduction of costs. A new form of partnership between the developed and developing countries is needed for transferring capital and technologies at special framework terms in order to avoid errors in the process of transition. The Energy Forum'99 highlights the current problems of Bulgarian energy branch and the projects for its future including better utilization of the existing energy resources, for development of new or renewable energy sources, not well utilized at present, and to harmonize the sector with better environmental protection. The most important problems discussed are: 1. Structure and restructuring strategy of the energy sector. Prices and tariffs. Privatization aspects. Construction of new replacement generating capacities; 2. Thermal power plants; 3. Nuclear power plants; 4. District heating and natural gas supply; 5. Efficient energy utilization; 6. Renewable energy sources; 7. Environmental protection and 8. Education

  14. NRC Information No. 88-98: Electrical relay degradation caused by oxidation of contact surfaces

    Rossi, C.E.

    1992-01-01

    The NRC staff was recently informed by Clinton Power Station that a reactor scram on June 24, 1988, was caused by an electrical relay failure from oxide buildup on relay contact surfaces. Other information on relay failure from contact oxidation indicates that this problem may be more prevalent than previously thought. For example, a July 17, 1988, 10 CFR Part 21 report from Palo Verde, Unit 2, reported relay failures from contact oxidation that were due to the low current application of the relays. The relay contact surfaces in both of these examples are silver-nickel alloys, and both applications were for low current (i.e., milli-ampere current). Electrical relay contacts made of silver-nickel or silver-cadmium alloys will oxidize (tarnish) when used in low current applications because of the absence of contact surface sparking from the typical relay contact ''making and breaking'' functions. The sparking in the contact surfaces promotes a self-cleaning mechanism that reduces the tarnish buildup on the silver-nickel or silver-cadmium contacts. Discussions with one relay manufacturer revealed that the normal industry practice for low current circuit applications is either to use a contact surface material that will not oxidize or to compensate for the oxidation by increased maintenance activities to ensure reliability. The applied voltage may also influence contact oxidation

  15. LANL Contacts

    : (505) 665-3664 ethics@lanl.gov Journalist queries Communications Office (505) 667-7000 Media contacts programs and employee resources. General Employee directory Emergency communication Communications Office (505) 667-7000 Ethics & Audits Internal Audit: (505) 665-3104 Ethics Office: (505) 667-7506 Fax

  16. Jet Fuel-Associated Occupational Contact Dermatitis.

    Contestable, James J

    2017-03-01

    Occupational contact dermatitis is a ubiquitous problem. Sailors onboard U.S. Navy vessels are at high risk given the multitude of potential workplace exposures. Solvents, petrochemicals, and fuels are abundant and can cause irritant or allergic contact dermatitis. Symptoms of contact dermatitis can cause inability to work and, if chronic, may require a change in rating or job. Prevention of this issue requires patient education about the risks and correct personnel protective equipment. Even with preventative strategies in place, exposures and cases of contact dermatitis will occur. Treatment consists of topical steroids and immunomodulators, as well as barrier creams and emollients. The goal of treatment is to fully restore the skin's natural barrier and prevent further exposure. A classic case of jet fuel-associated contact dermatitis is reviewed. A literature review utilizing PubMed, Google Scholar, and Google Search was conducted to elucidate our understanding of this issue, current occupational health guidelines, preventative approaches, and treatments. This case report provides guidance and recommendations for providers who encounter contact dermatitis related to petrochemicals, such as jet fuel. The literature review revealed limited knowledge surrounding in vivo human skin effects of jet fuel, specifically JP-5. Even larger gaps were found in our understanding of, and guidelines for, protective modalities against jet fuel exposure and dermatitis. A case is presented to facilitate recognition of jet fuel contact dermatitis and guidance for treatment and prevention. Given our current limited knowledge and guidelines concerning protective equipment and skin protectants, multiple proposals for future studies are suggested. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

  17. Optimal contact definition for reconstruction of Contact Maps

    Stehr Henning

    2010-05-01

    Full Text Available Abstract Background Contact maps have been extensively used as a simplified representation of protein structures. They capture most important features of a protein's fold, being preferred by a number of researchers for the description and study of protein structures. Inspired by the model's simplicity many groups have dedicated a considerable amount of effort towards contact prediction as a proxy for protein structure prediction. However a contact map's biological interest is subject to the availability of reliable methods for the 3-dimensional reconstruction of the structure. Results We use an implementation of the well-known distance geometry protocol to build realistic protein 3-dimensional models from contact maps, performing an extensive exploration of many of the parameters involved in the reconstruction process. We try to address the questions: a to what accuracy does a contact map represent its corresponding 3D structure, b what is the best contact map representation with regard to reconstructability and c what is the effect of partial or inaccurate contact information on the 3D structure recovery. Our results suggest that contact maps derived from the application of a distance cutoff of 9 to 11Å around the Cβ atoms constitute the most accurate representation of the 3D structure. The reconstruction process does not provide a single solution to the problem but rather an ensemble of conformations that are within 2Å RMSD of the crystal structure and with lower values for the pairwise average ensemble RMSD. Interestingly it is still possible to recover a structure with partial contact information, although wrong contacts can lead to dramatic loss in reconstruction fidelity. Conclusions Thus contact maps represent a valid approximation to the structures with an accuracy comparable to that of experimental methods. The optimal contact definitions constitute key guidelines for methods based on contact maps such as structure prediction through

  18. The formulation of dynamical contact problems with friction in the case of systems of rigid bodies and general discrete mechanical systems—Painlevé and Kane paradoxes revisited

    Charles, Alexandre; Ballard, Patrick

    2016-08-01

    The dynamics of mechanical systems with a finite number of degrees of freedom (discrete mechanical systems) is governed by the Lagrange equation which is a second-order differential equation on a Riemannian manifold (the configuration manifold). The handling of perfect (frictionless) unilateral constraints in this framework (that of Lagrange's analytical dynamics) was undertaken by Schatzman and Moreau at the beginning of the 1980s. A mathematically sound and consistent evolution problem was obtained, paving the road for many subsequent theoretical investigations. In this general evolution problem, the only reaction force which is involved is a generalized reaction force, consistently with the virtual power philosophy of Lagrange. Surprisingly, such a general formulation was never derived in the case of frictional unilateral multibody dynamics. Instead, the paradigm of the Coulomb law applying to reaction forces in the real world is generally invoked. So far, this paradigm has only enabled to obtain a consistent evolution problem in only some very few specific examples and to suggest numerical algorithms to produce computational examples (numerical modeling). In particular, it is not clear what is the evolution problem underlying the computational examples. Moreover, some of the few specific cases in which this paradigm enables to write down a precise evolution problem are known to show paradoxes: the Painlevé paradox (indeterminacy) and the Kane paradox (increase in kinetic energy due to friction). In this paper, we follow Lagrange's philosophy and formulate the frictional unilateral multibody dynamics in terms of the generalized reaction force and not in terms of the real-world reaction force. A general evolution problem that governs the dynamics is obtained for the first time. We prove that all the solutions are dissipative; that is, this new formulation is free of Kane paradox. We also prove that some indeterminacy of the Painlevé paradox is fixed in this

  19. [Current status of the standardization of air impulse tonometers and their evaluation--as an example: the Non-Contact Tonometer II].

    Jessen, K; Hoffmann, F

    1983-10-01

    The standard values and tolerances used in the assessment of the clinical efficiency of different types of tonometers are once again demonstrated. Investigations carried out in accordance with the existing test plan for comparative clinical measurements using two non-contact tonometers II (NCT II) and a calibrated applanation tonometer as a reference instrument in 155 patient eyes showed that both the regression equation and the scattering of the individual values around the regression curve satisfy the conditions of clinical assessment criteria. Of the individual values, 2.6% are outside the 95% limits. Following a brief illustration of the measuring principle of the NCT II, a test procedure is described for this type of tonometer. It consists of a torsion balance mounted on a cross-sliding carriage with a small mirror 2.5 mm in diameter and a control balance. A lens equipped with a centering cross is used for adjustment to the nominal distances of 11 mm between the nozzle and the cornea. This test procedure makes it possible to determine whether the digital display of any particular NTC II deviates from the nominal value by not more than +/- 1 digit in the range between "12" and "30" and by not more than +/- 2 digits between "31" and "50".

  20. A case against bio markers as they are currently used in radioecological risk analyses: a problem of linkage

    Hinton, T.G.; Brechignac, F.

    2005-01-01

    Bio-markers are successfully used in human risk analyses as early indicators of contaminant exposure and predictors of deleterious effects. This has boosted the search for bio-markers in determining ecological risks to non-human biota, and particularly for assessments related to radioactive contaminants. There are difficulties, however, that prevent an easy transfer of the bio-marker concept from humans to non-human biota, as there are significant differences in endpoints of concern, units of observation and dose response relationships between human and ecological risk analyses. The use of bio-markers in ecological risk analyses currently lacks a linkage between molecular-level effects and quantifiable impacts observed in individuals and populations. This is important because ecological risk analyses generally target the population level of biological organisation. We highlight various examples that demonstrate the difficulties of linking individual responses to population-level impacts, such as indirect effects and compensatory interactions. Eco-toxicologists cope with such difficulties through the use of uncertainty or extrapolation factors. Extrapolation factors (EF) typically range from 1 to 1000 when linking effects observed in individuals to those predicted to occur in populations. We question what magnitude of EF will be required when going from a molecular level effect, measured by a bio-marker, all the way up to the population level of biological organisation. Particularly, we stress that a successful application of bio-markers to radioecological risk assessment can only be achieved once the connection has been made between changes in individual resource allocation-based life histories and population dynamics. This clearly emphasises the need to quantify the propagation of molecular and cellular level effects to higher levels of biological organisation, especially in the long-term via several generations of exposure. Finally, we identify pertinent research

  1. Prioritized Contact Transport Stream

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  2. A non-contacting thermal wave technique for NDT of coatings and other applications in the CEGB: current status (July 1987)

    Corbett, J.; Quigley, M.B.C.; Smith, B.L.; Hart, B.

    1988-10-01

    This report describes the current status of the photothermal non-destructive testing (NDT) of sprayed coatings on components in conventional and nuclear power plant. Thickness measurements of sprayed coatings have been performed and the thickness resolution capability has been shown to be, in principle, of the order of 1 micrometre. Sub-surface defects down to 0.5mm is size have been detected, using a tightly focused laser beam. The ability to distinguish between penetrated and non-penetrated welds has been illustrated. A portable diode-laser based system is being designed for on-line manufacturing quality assurance and in-situ inspection of coatings. Finally, the potential cost benefit and current research programme are outlined. (author)

  3. ALLERGIC CONTACT DERMATITIS

    Trisna Yuliharti Tersinanda

    2013-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Allergic contact dermatitis is an immunologic reaction that tends to involve the surrounding skin and may even spread beyond affected sites. This skin disease is one of the more frequent, and costly dermatologic problems. Recent data from United Kingdom and United States suggest that the percentage of occupational contact dermatitis due to allergy may be much higher, thus raising the economic impact of occupational allergic contact dermatitis. There is not enough data about the epidemiology of allergic contact dermatitis in Indonesia, however based on research that include beautician in Denpasar, about 27,6 percent had side effect of cosmetics, which is 25,4 percent of it manifested as allergic contact dermatitis. Diagnosis of allergic contact dermatitis is based on anamnesis, physical examination, patch test, and this disease should be distinguished from other eczematous skin disease. The management is prevention of allergen exposure, symptomatic treatment, and physicochemical barrier /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  4. Report on the second Congress of the Russian nuclear medicine society and on International conference Current problems of nuclear medicine and radiopharmaceuticals

    Lishmanov, Yu.B.; Chernov, V.I.

    2001-01-01

    Information on the work of Second Congress of Russian Nuclear Medicine Society and International Conference - Current problems of nuclear medicine and radiopharmaceuticals, - held in Obninsk in October, 2000, is adduced. Reports presented in the conference are dedicated to various aspects of application of radionuclide methods to cardiology, angiology, oncology, surgery, hematology, endocrinology, pediatrics and neurology. Problems in the development of radiopharmaceutical, training and skill advancement of experts, dosimetry and radiation safety in nuclear medicine were discussed. Congress considered the organizational problems in Russian nuclear medicine [ru

  5. Contact: Releasing the news

    Pinotti, Roberto

    The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

  6. The influence of stabilizers on the production of gold nanoparticles by direct current atmospheric pressure glow microdischarge generated in contact with liquid flowing cathode

    Dzimitrowicz, Anna; Jamroz, Piotr, E-mail: piotr.jamroz@pwr.edu.pl; Greda, Krzysztof; Nowak, Piotr; Nyk, Marcin; Pohl, Pawel [Wroclaw University of Technology, Faculty of Chemistry (Poland)

    2015-04-15

    Gold nanoparticles (Au NPs) were prepared by direct current atmospheric pressure glow microdischarge (dc-μAPGD) generated between a miniature argon flow microjet and a flowing liquid cathode. The applied discharge system was operated in a continuous flow liquid mode. The influence of various stabilizers added to the solution of the liquid cathode, i.e., gelatin (GEL), polyvinylpyrrolidone (PVP), or polyvinyl alcohol (PVA), as well as the concentration of the Au precursor (chloroauric acid, HAuCl{sub 4}) in the solution on the production growth of Au NPs was investigated. Changes in the intensity of the localized surface plasmon resonance (LSPR) band in UV/Vis absorption spectra of solutions treated by dc-μAPGD and their color were observed. The position and the intensity of the LSPR band indicated that relatively small nanoparticles were formed in solutions containing GEL as a capping agent. In these conditions, the maximum of the absorption LSPR band was at 531, 534, and 535 nm, respectively, for 50, 100, and 200 mg L{sup −1} of Au. Additionally, scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to analyze the structure and the morphology of obtained Au NPs. The shape of Au NPs was spherical and uniform. Their mean size was ca. 27, 73, and 92 nm, while the polydispersity index was 0.296, 0.348, and 0.456 for Au present in the solution of the flowing liquid cathode at a concentration of 50, 100, and 200 mg L{sup −1}, respectively. The production rate of synthesized Au NPs depended on the precursor concentration with mean values of 2.9, 3.5, and 5.7 mg h{sup −1}, respectively.

  7. The influence of stabilizers on the production of gold nanoparticles by direct current atmospheric pressure glow microdischarge generated in contact with liquid flowing cathode

    Dzimitrowicz, Anna; Jamroz, Piotr; Greda, Krzysztof; Nowak, Piotr; Nyk, Marcin; Pohl, Pawel

    2015-04-01

    Gold nanoparticles (Au NPs) were prepared by direct current atmospheric pressure glow microdischarge (dc-μAPGD) generated between a miniature argon flow microjet and a flowing liquid cathode. The applied discharge system was operated in a continuous flow liquid mode. The influence of various stabilizers added to the solution of the liquid cathode, i.e., gelatin (GEL), polyvinylpyrrolidone (PVP), or polyvinyl alcohol (PVA), as well as the concentration of the Au precursor (chloroauric acid, HAuCl4) in the solution on the production growth of Au NPs was investigated. Changes in the intensity of the localized surface plasmon resonance (LSPR) band in UV/Vis absorption spectra of solutions treated by dc-μAPGD and their color were observed. The position and the intensity of the LSPR band indicated that relatively small nanoparticles were formed in solutions containing GEL as a capping agent. In these conditions, the maximum of the absorption LSPR band was at 531, 534, and 535 nm, respectively, for 50, 100, and 200 mg L-1 of Au. Additionally, scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to analyze the structure and the morphology of obtained Au NPs. The shape of Au NPs was spherical and uniform. Their mean size was ca. 27, 73, and 92 nm, while the polydispersity index was 0.296, 0.348, and 0.456 for Au present in the solution of the flowing liquid cathode at a concentration of 50, 100, and 200 mg L-1, respectively. The production rate of synthesized Au NPs depended on the precursor concentration with mean values of 2.9, 3.5, and 5.7 mg h-1, respectively.

  8. Application of Direct Current Atmospheric Pressure Glow Microdischarge Generated in Contact with a Flowing Liquid Solution for Synthesis of Au-Ag Core-Shell Nanoparticles.

    Dzimitrowicz, Anna; Jamroz, Piotr; Nyk, Marcin; Pohl, Pawel

    2016-04-06

    A direct current atmospheric pressure glow microdischarge (dc-μAPGD) generated between an Ar nozzle microjet and a flowing liquid was applied to produce Au-Ag core-shell nanoparticles (Au@AgCSNPs) in a continuous flow system. Firstly, operating dc-μAPGD with the flowing solution of the Au(III) ions as the cathode, the Au nanoparticles (AuNPs) core was produced. Next, to produce the core-shell nanostructures, the collected AuNPs solution was immediately mixed with an AgNO₃ solution and passed through the system with the reversed polarity to fabricate the Ag nanoshell on the AuNPs core. The formation of Au@AgCSNPs was confirmed using ultraviolet-visible (UV-Vis) absorbance spectrophotometry, transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Three localized surface plasmon resonance absorption bands with wavelengths centered at 372, 546, and 675 nm were observed in the UV-Vis spectrum of Au@AgCSNPs, confirming the reduction of both the Au(III) and Ag(I) ions. The right configuration of metals in Au@AgCSNPs was evidenced by TEM. The Au core diameter was 10.2 ± 2.0 nm, while the thickness of the Ag nanoshell was 5.8 ± 1.8 nm. The elemental composition of the bimetallic nanoparticles was also confirmed by EDS. It is possible to obtain 90 mL of a solution containing Au@AgCSNPs per hour using the applied microdischarge system.

  9. Contact Lens Care

    ... Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More sharing ... www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative Contact ...

  10. International Conference 'Current Problems in Nuclear Physics and Atomic Energy'. May 29 - Jun 03 2006. Book of Abstracts

    Vyshnevskyi, I.M.

    2006-01-01

    The collective processes in atomic nuclei, nuclear reactions and processes with exotic nuclei, rare nuclear processes, relativistic nuclear physics, neutron physics, physics of nuclear reactors, problems of atomic energy and reactors of the future, applied nuclear physics and technique of experiments was discussed in this conference

  11. Current Problems of Improving the Environmental Certification and Output Compliance Verification in the Context of Environmental Management in Kazakhstan

    Zhambaev, Yerzhan S.; Sagieva, Galia K.; Bazarbek, Bakhytzhan Zh.; Akkulov, Rustem T.

    2016-01-01

    The article discusses the issues of improving the activity of subjects of environmental management in accordance with international environmental standards and national environmental legislation. The article deals with the problem of ensuring the implementation of international environmental standards, the introduction of eco-management, and the…

  12. Contact Allergy in Danish Healthcare Workers

    Schwensen, Jakob F; Menné, Torkil; Sommerlund, Mette

    2016-01-01

    Contact dermatitis in healthcare workers is a pan-European problem. We conducted a retrospective observational study of the patch-test results of 1402 healthcare workers and 1402 matched controls with contact dermatitis who were treated at 3 hospitals departments in Denmark between 2007 and 2014....... The primary objective was to determine whether healthcare work was associated with contact allergy to thiuram mix. Unadjusted univariate analyses revealed that healthcare work was significantly associated with occupational contact dermatitis and hand dermatitis. Contact allergy to thiuram mix was more common...... in healthcare workers was significantly associated with having occupational contact dermatitis, hand dermatitis and older age. In conclusion, we report here a potential problem of contact allergy to thiurams in healthcare workers with contact dermatitis. Legislative authorities may in the future focus...

  13. Review of prediction for thermal contact resistance

    2010-01-01

    Theoretical prediction research on thermal contact resistance is reviewed in this paper. In general, modeling or simulating the thermal contact resistance involves several aspects, including the descriptions of surface topography, the analysis of micro mechanical deformation, and the thermal models. Some key problems are proposed for accurately predicting the thermal resistance of two solid contact surfaces. We provide a perspective on further promising research, which would be beneficial to understanding mechanisms and engineering applications of the thermal contact resistance in heat transport phenomena.

  14. Magnetic diagnostics: General principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

    Pustovitov, V.D.

    2001-01-01

    Restrictions on magnetic diagnostics are discussed. Being related to the integral nature of the measurable quantities, these follow from the fundamental laws of electromagnetism. A series of examples demonstrating the strength of these restrictions is analysed. The general rule is emphasized that information obtained from external magnetic measurements is insufficient for reliable evaluation of plasma current and pressure profiles in tokamaks and in stellarators. The underlying reason is that outside the plasma the self-field of the equilibrium plasma currents is determined by the boundary conditions on the plasma surface alone. (author)

  15. Magnetic diagnostics: general principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

    Pustovitov, V.D.

    2000-04-01

    The restrictions of the magnetic diagnostics are discussed. Being related to the integral nature of the measurable quantities, they follow from the fundamental laws of electromagnetism. A series of particular examples demonstrating the strength of these restrictions is given and analyzed. A general rule is emphasized that the information obtained from external magnetic measurements is obviously insufficient for the reliable evaluation of plasma current and pressure profiles in tokamaks or in stellarators. The underlying reason is that outside the plasma the own field of the equilibrium plasma currents is determined by the boundary conditions on the plasma surface only. (author)

  16. Analyzing the problems with the current adoption of IFRS in the companies among India, China, Germany, Russia and Kenya

    Robert Mosomi Ombati; Anita Shukla

    2018-01-01

    Accounting information provides past and current financial information of an economic unit for business managers, potential investors, and other interested parties. Internally generated accounting information helps business managers with planning, controlling, and making decisions referred to as managerial accounting information. However, if the companies, which have adopted International Financial Reporting Standards (IFRS) globally, cannot generate the same information then the accounting p...

  17. Several problems of algorithmization in integrated computation programs on third generation computers for short circuit currents in complex power networks

    Krylov, V.A.; Pisarenko, V.P.

    1982-01-01

    Methods of modeling complex power networks with short circuits in the networks are described. The methods are implemented in integrated computation programs for short circuit currents and equivalents in electrical networks with a large number of branch points (up to 1000) on a computer with a limited on line memory capacity (M equals 4030 for the computer).

  18. Identifying criteria for multimodel software process improvement solutions : based on a review of current problems and initiatives

    Kelemen, Z.D.; Kusters, R.J.; Trienekens, J.J.M.

    2012-01-01

    In this article, we analyze current initiatives in multimodel software process improvement and identify criteria for multimodel solutions. With multimodel, we mean the simultaneous usage of more than one quality approach (e.g. standards, methods, techniques to improve software processes). This paper

  19. A Socio-Cultural Reframing of Science and Dis/ability in Education: Past Problems, Current Concerns, and Future Possibilities

    Connor, David J.; Valle, Jan W.

    2015-01-01

    In this article we assert the value of a socio-cultural reframing of science and dis/ability in education. We begin by problematizing current issues in education pertaining to the often-unquestioned concept of dis/ability and the impact that has upon research, theory, practice, and policy. As our topic is broad, we have chosen to focus upon four…

  20. Depression and Associated Suicidal Behaviour in Children and Adolescents: Current Views and the Problem State Part 2

    S.V. Rymsha

    2014-10-01

    Full Text Available There has been performed the analytical analysis of the world literature dedicated to the epidemiology, etiology, current approaches to the pathogenesis, clinical picture and diagnosis criteria for the depressive disorders in children and adolescents as well as the associated suicidal behavior and the social significance of this disease with its consequences. Key recommendations on the treatment and prophylaxis of depression in children and adolescents according to the last evidence-base European and American guidelines are considered.

  1. Current and future prospects for the application of systematic theoretical methods to the study of problems in physical oceanography

    Constantin, A., E-mail: adrian.constantin@kcl.ac.uk [Department of Mathematics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Faculty of Mathematics, University of Vienna, Oskar-Morgenstern-Platz 1, 1090 Vienna (Austria); Johnson, R.S., E-mail: r.s.johnson@ncl.ac.uk [School of Mathematics & Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2016-09-07

    Highlights: • Systematic theoretical methods in studies of equatorial ocean dynamics. • Linear wave-current interactions in stratified flows. • Exact solutions – Kelvin waves, azimuthal non-uniform currents. • Three-dimensional nonlinear currents. • Hamiltonian formulation for the governing equations and for structure-preserving/enhancing approximations. - Abstract: This essay is a commentary on the pivotal role of systematic theoretical methods in physical oceanography. At some level, there will always be a conflict between theory and experiment/data collection: Which is pre-eminent? Which should come first? This issue appears to be particularly marked in physical oceanography, to the extreme detriment of the development of the subject. It is our contention that the classical theory of fluids, coupled with methods from the theory of differential equations, can play a significant role in carrying the subject, and our understanding, forward. We outline the philosophy behind a systematic theoretical approach, highlighting some aspects of equatorial ocean dynamics where these methods have already been successful, paving the way for much more in the future and leading, we expect, to the better understanding of this and many other types of ocean flow. We believe that the ideas described here promise to reveal a rich and beautiful dynamical structure.

  2. Current Economic and Financial Crisis – New Issues or Returning to the Old Problems? Paradigms, Causes, Effects and Solutions Adopted

    Felix TOTIR

    2011-01-01

    Full Text Available At the ideological level, the current crisis, as the others in history, has triggered an intellectual debate among several applicable ideas: ultra-liberal theory of the "invisible hand" of Adam Smith, Keynes's theory of state interventionism and even neo-Marxist theories. Globalization, with all its core components, generates a chain reaction when the phenomenon occurs, either positive or negative. The origin of the current financial crisis should be sought in the effects of massive cross-border capital flows and the use of more complex derivatives. Reaching the saturation of the three engines of economic growth worldwide in the period after the collapse of the socialist bloc is another important cause of all the failures that currently exist worldwide. Acquisition of toxic assets from bank balance sheets, their recapitalization and takeover by the state, but also the reinforcement of the prudential supervision of capitalization, liquidity and risk management system, improved transparency and speed the process of evaluating or reinforcing authorities' response to risk, can be considered short or long term anti-crisis measures, as appropriate.

  3. Contact Zones, Problem Posing and Critical Consciousness

    Patel, Lisa

    2012-01-01

    In this article, I share the shape and findings of a participatory action research project with newcomer youths on the contours of status in society. This project was nested in a professional internship experience for newcomer youth, and this experience provided the context in which we explored how privilege and status are afforded in American…

  4. Occupational contact urticaria and protein contact dermatitis.

    Doutre, Marie-Sylvie

    2005-01-01

    Irritant dermatitis and eczema are the most prevalent occupational skin diseases. Less common are immediate contact reactions such as contact urticaria and protein contact dermatitis. Occupational contact urticaria can be subdivided into two categories, immunological and non immunological. However, some agents can induce these two types of reactions. Contact urticaria to natural rubber latex is particularly frequent among health care personnel, but contact urticaria to a wide variety of other substances occurs in many other occupations. Among those at risk are cooks, bakers, butchers, restaurant personnel, veterinarians, hairdressers, florists, gardeners, and forestry workers. Protein contact dermatitis in some of these occupations is caused principally by proteins of animal or plant origin, especially among individuals with a history of atopic dermatitis. Diagnosis requires careful interrogation, clinical examination and skin tests (open tests and prick tests with immediate lecture) to identify a particular contact allergen.

  5. Solar Cels With Reduced Contact Areas

    Daud, T.; Crotty, G. T.; Kachare, A. H.; Lewis, J. T.

    1987-01-01

    Efficiency of silicon solar cells increased about 20 percent using smaller metal-contact area on silicon at front and back of each cell. Reduction in contact area reduces surface recombination velocity under contact and thus reduces reverse saturation current and increases opencircuit voltage..

  6. Reliability growth of thin film resistors contact

    Lugin A. N.

    2010-10-01

    Full Text Available Necessity of resistive layer growth under the contact and in the contact zone of resistive element is shown in order to reduce peak values of current flow and power dissipation in the contact of thin film resistor, thereby to increase the resistor stability to parametric and catastrophic failures.

  7. Research advances in contact model and mechanism configuration for nut shelling manipulation based on metamorphic method

    Xiulan BAO

    2017-04-01

    Full Text Available Nuts are the important economic forest tree species of China. De-shell is the key operation of nut deep processing. There are some problems in the current nut cracking devices such as the low decorticating rate, the high nuts losses rate and nutmeat integrity problems, etc.. The foundation of force analysis is to establish contact model for nut and mechanical. The nut surface is rough and irregular, so the contact area cannot be modeled as regular shape. How to set up contact constraint model is the key problem to accomplish non-loss shelling. In order to study the shell-breaking mechanism and structural design of the nut shelling manipulation, a multi-fingered metamorphic manipulator is presented. An overview of the nut shelling technology and the contact manipulator modeling are proposed. The origin and application of metamorphic mechanisms are introduced. Then the research contents and development prospects of nut shelling manipulator are described.

  8. Monitoring of radioactive ferrous scarp and products, current practices and regulatory problems in North-Eastern Italy

    Barbina, V.; Bianco, L.

    1997-01-01

    Radioactive scrap metal is a major source of concern among the steel industries of northeastern Italy, since most of the scrap supply comes from east-European countries and may originate from dismantled nuclear installations or dismissed radioactive devices. In this respect reliable monitoring procedures and consistent regulations are essential to face the many economic, legal and safety problems involved in the control and management of radioactive scrap and products. The authors describe the monitoring methods developed in more than two years practice at the steel works Ferriere Nord, Osoppo UD, Italy, as a realistic compromise between reliability, radiation protection and cost. They also discuss the drawbacks sometimes due to the lack of coherent monitoring protocols and exemption levels in Italian regulations, which leave some ways out for the uncontrolled recycling of radioactive metal scrap. (author)

  9. 4. International Conference on Current Problems in Nuclear Physics and Atomic Energy (NPAE-Kyiv2012). Proceedings. Part I and Part II

    Vyshnevskyi, Ivan M.

    2012-01-01

    Such wide area of topics, discussed during the Conference, is closely connected with the interests of our country to develop the fundamental research in the field of nuclear physics, which is the base of nuclear energy. The purpose of the Conference was to bring together scientists to share their knowledge in the current problems in nuclear physics and atomic energy. consideration of the spherical ground-state proton emitters, while nuclear deformations are supposed to be further included by standard way

  10. Non-conformal contact mechanical characteristic analysis on spherical components

    Zhen-zhi, G.; Bin, H.; Zheng-ming, G.; Feng-mei, Y.; Jin, Q [The 2. Artillery Engineering Univ., Xi' an (China)

    2017-03-15

    Non-conformal spherical-contact mechanical problems is a three-dimensional coordination or similar to the coordination spherical contact. Due to the complexity of the problem of spherical-contact and difficulties of solving higher-order partial differential equations, problems of three-dimensional coordination or similar to the coordination spherical-contact is still no exact analytical method for solving. It is based on three-dimensional taper model is proposed a model based on the contour surface of the spherical contact and concluded of the formula of the contact pressure and constructed of finite element model by contact pressure distribution under the non-conformal spherical. The results shows spherical contact model can reflect non-conformal spherical-contacting mechanical problems more than taper-contacting model, and apply for the actual project.

  11. Currents and the energy-momentum tensor in classical field theory: a fresh look at an old problem

    Forger, Michael; Roemer, Hartmann

    2004-01-01

    We give a comprehensive review of various methods to define currents and the energy-momentum tensor in classical field theory, with emphasis on a geometric point of view. The necessity of 'improving' the expressions provided by the canonical Noether procedure is addressed and given an adequate geometric framework. The main new ingredient is the explicit formulation of a principle of 'ultralocality' with respect to the symmetry generators, which is shown to fix the ambiguity inherent in the procedure of improvement and guide it towards a unique answer: when combined with the appropriate splitting of the fields into sectors, it leads to the well-known expressions for the current as the variational derivative of the matter field Lagrangian with respect to the gauge field and for the energy-momentum tensor as the variational derivative of the matter field Lagrangian with respect to the metric tensor. In the second case, the procedure is shown to work even when the matter field Lagrangian depends explicitly on the curvature, thus establishing the correct relation between scale invariance, in the form of local Weyl invariance 'on shell', and tracelessness of the energy-momentum tensor, required for a consistent definition of the concept of a conformal field theory

  12. Current approaches to improve the anticancer chemotherapy with alkylating agents: state of the problem in world and Ukraine.

    Iatsyshyna A. P.

    2012-01-01

    Full Text Available Alkylating agents are frequently used in many established anticancer chemotherapies. They alkylate the genomic DNA at various sites. Alkylation of the guanine at the O6-position is cytotoxic, it has the strongest mutagenic potential, as well as can cause the tumor development. Alkyl groups at the O6-position of guanine are removed by the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT. The effectiveness of alkylating chemotherapy is limited by MGMT in cancer cells and adverse toxic side effects in normal cells. Different approaches consisting in the modulation of the MGMT expression and activity are under development now to improve the cancer chemotherapy. They include two main directions, in particular, the increase in chemosensitivity of cancer cells to alkylating drugs and the protection of normal cells from the toxic side effects of chemotherapy. This review is focused on current attempts to improve the alkylating chemotherapy of malignant tumours worldwide and state of the issue in Ukraine

  13. Colored Contact Lens Dangers

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

  14. Colored Contact Lens Dangers

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  15. [Current status and problems of regional maternal and child health education in the curriculum of midwifery education].

    Murayama, I

    1989-01-01

    According to the evaluations made by medical Technical Junior Colleges in Japan, general objectives in midwifery education are met, but their curriculum does not cater to each region's health care needs sufficiently. Japanese midwifery students can either attend a 6 month training program offered at 80 different locations, or enroll in a 1 year special-major program at one of the 10 Medical Technical Junior Colleges affiliated with National Universities. According to the curriculum revised in 1971, midwifery students are required to take the following courses and hours in 6 months. Intro. to Maternal and Child Health (15 hours), Maternal and Child Health Medicine (60 hours), Lecture on Midwifery (105 hrs), Practice in Midwifery (135 hrs), Midwifery Business Administration (60 hrs), Maternal and Child Health Administration including internship (225 hrs), Regional Maternal and Child Health including internship (105 hrs) and Family Sociology (15 hours). Regional Maternal and Child Health course (RMCH) is effectively taught only if all the maternal and child health courses and lecture on midwifery are taken beforehand. Objectives for RMCH course are becoming able to assess the state of maternal and child health care in the region and give constructive criticism and suggestions for improvement including legal aspects, acquiring positive attitudes and necessary skills for advancing and having understanding of regional health care and that of midwives' role of it. While the curriculum prepares the students for meeting the patients' physical needs, the students are not ready to cope with their psychological and socio-physiological problems surrounding individuals, families and communities. Changes and diversification of regional communities should be taken into consideration also in the curriculum. Increase in nuclear families, increase in working wives, isolation and/or over-crowding of high rise apartment living are some of the examples. Midwifery activity is also

  16. How artificial intelligence tools can be used to assess individual patient risk in cardiovascular disease: problems with the current methods

    Grossi Enzo

    2006-05-01

    Full Text Available Abstract Background In recent years a number of algorithms for cardiovascular risk assessment has been proposed to the medical community. These algorithms consider a number of variables and express their results as the percentage risk of developing a major fatal or non-fatal cardiovascular event in the following 10 to 20 years Discussion The author has identified three major pitfalls of these algorithms, linked to the limitation of the classical statistical approach in dealing with this kind of non linear and complex information. The pitfalls are the inability to capture the disease complexity, the inability to capture process dynamics, and the wide confidence interval of individual risk assessment. Artificial Intelligence tools can provide potential advantage in trying to overcome these limitations. The theoretical background and some application examples related to artificial neural networks and fuzzy logic have been reviewed and discussed. Summary The use of predictive algorithms to assess individual absolute risk of cardiovascular future events is currently hampered by methodological and mathematical flaws. The use of newer approaches, such as fuzzy logic and artificial neural networks, linked to artificial intelligence, seems to better address both the challenge of increasing complexity resulting from a correlation between predisposing factors, data on the occurrence of cardiovascular events, and the prediction of future events on an individual level.

  17. Computer-aided detection in computed tomography colonography. Current status and problems with detection of early colorectal cancer

    Morimoto, Tsuyoshi; Nakijima, Yasuo; Iinuma, Gen; Arai, Yasuaki; Shiraishi, Junji; Moriyama, Noriyuki; Beddoe, G.

    2008-01-01

    The aim of this study was to evaluate the usefulness of computer-aided detection (CAD) in diagnosing early colorectal cancer using computed tomography colonography (CTC). A total of 30 CTC data sets for 30 early colorectal cancers in 30 patients were retrospectively reviewed by three radiologists. After primary evaluation, a second reading was performed using CAD findings. The readers evaluated each colorectal segment for the presence or absence of colorectal cancer using five confidence rating levels. To compare the assessment results, the sensitivity and specificity with and without CAD were calculated on the basis of the confidence rating, and differences in these variables were analyzed by receiver operating characteristic (ROC) analysis. The average sensitivities for the detection without and with CAD for the three readers were 81.6% and 75.6%, respectively. Among the three readers, only one reader improved sensitivity with CAD compared to that without. CAD decreased specificity in all three readers. CAD detected 100% of protruding lesions but only 69.2% of flat lesions. On ROC analysis, the diagnostic performance of all three readers was decreased by use of CAD. Currently available CAD with CTC does not improve diagnostic performance for detecting early colorectal cancer. An improved CAD algorithm is required for detecting fiat lesions and reducing the false-positive rate. (author)

  18. Elevated vaginal pH in the absence of current vaginal infection, still a challenging obstetrical problem.

    Hantoushzadeh, Sedigheh; Sheikh, Mahdi; Javadian, Pouya; Shariat, Mamak; Amini, Elaheh; Abdollahi, Alireza; Kashanian, Maryam

    2014-04-01

    To assess the association of vaginal pH ≥ 5 in the absence of vaginal infection with systemic inflammation and adverse pregnancy outcome. Four-hundred sixty pregnant women completed the study, upon enrollment Vaginal pH was measured for all women, maternal and umbilical sera were obtained for determining C-reactive protein (CRP) and uric acid levels. Umbilical blood was tested for gas parameters, 1 and 5 min Apgar scores, the need for neonatal resuscitation and neonatal intensive care unit (NICU) admission were recorded. Elevated vaginal pH was significantly associated with preterm birth (odds ratio (OR), 2.23; 95% confidence interval (CI), 1.04-4.76), emergency cesarean section (OR 2.57; 95% CI 1.32-5), neonatal resuscitation in the delivery room (OR 2.85; 95% CI 1.1-7.38), elevated cord base deficit (OR 8.01; 95% CI 1.61-39.81), low cord bicarbonate (OR 4.16, 95% CI 1.33-12.92) and NICU admission (OR 2.02; 95% CI 1.12-3.66). Increased vaginal pH was also significantly associated with maternal leukocytosis, hyperuricemia and elevated CRP levels in maternal and umbilical sera. Elevated vaginal pH in the absence of current vaginal infection still constitutes a risk for adverse pregnancy outcome which is mediated by systemic inflammatory response.

  19. A socio-cultural reframing of science and dis/ability in education: past problems, current concerns, and future possibilities

    Connor, David J.; Valle, Jan W.

    2015-12-01

    In this article we assert the value of a socio-cultural reframing of science and dis/ability in education. We begin by problematizing current issues in education pertaining to the often-unquestioned concept of dis/ability and the impact that has upon research, theory, practice, and policy. As our topic is broad, we have chosen to focus upon four interconnected areas: (1) the historical mistrust of science and pseudo-science by people with dis/abilities; (2) the pervasive use of pseudo-science within the contemporary field of special education; (3) the use of dis/ability studies in education (DSE) to provide a contrast between a traditional positivist framing and a socio-cultural framing of dis/ability, and; (4) a brief exploration of what a DSE/socio-cultural grounding looks like for both schools and classroom teachers. In sum, our intention is to engage science educators to reject deficit-notions of dis/ability in favor of understanding it as part of human variation, and consider the personal and professional benefits of this shift.

  20. How artificial intelligence tools can be used to assess individual patient risk in cardiovascular disease: problems with the current methods.

    Grossi, Enzo

    2006-05-03

    In recent years a number of algorithms for cardiovascular risk assessment has been proposed to the medical community. These algorithms consider a number of variables and express their results as the percentage risk of developing a major fatal or non-fatal cardiovascular event in the following 10 to 20 years The author has identified three major pitfalls of these algorithms, linked to the limitation of the classical statistical approach in dealing with this kind of non linear and complex information. The pitfalls are the inability to capture the disease complexity, the inability to capture process dynamics, and the wide confidence interval of individual risk assessment. Artificial Intelligence tools can provide potential advantage in trying to overcome these limitations. The theoretical background and some application examples related to artificial neural networks and fuzzy logic have been reviewed and discussed. The use of predictive algorithms to assess individual absolute risk of cardiovascular future events is currently hampered by methodological and mathematical flaws. The use of newer approaches, such as fuzzy logic and artificial neural networks, linked to artificial intelligence, seems to better address both the challenge of increasing complexity resulting from a correlation between predisposing factors, data on the occurrence of cardiovascular events, and the prediction of future events on an individual level.

  1. Karl Rahner, Walter Kasper and Hans Kung on the Current State, Problems and Dimensions of Contemporary theology

    Pilipenko Evgenii

    2017-06-01

    Full Text Available Political history, philosophy, culture and science of the 19th century came to be very important factors in the development of Christian theology, primarily in Western Europe. Major issues of correlation between modern science, philosophical concepts of the modern period, secular ethics and Christianity led to a revision of many traditional theological concepts. There were suggested new methods of solving urgent theological, pastoral and missionary problems. The Second Vatican Ecumenical Council of Roman Catholic Church represented a vivid and constructive response to contemporary challenges. German theologians were among those who contributed significantly to the dialogue between the Church and modern world. The central fi gure among them was Karl Rahner. Using achievements of modern European thought, especially transcendental and existential philosophy, Rahner made Christian theology tenable for modern historical criticism and placed the person and the experience of faith as a crucial object of theological investigation. It may seem a paradox, but the unity of Catholic dogma in the 20th century came to be established not on the unity of the formal scholastic doctrine, proclaimed straightforwardly by Church magisterium, but on theological pluralism and historical dynamism, as well as on hermeneutical analysis of the dogma and inexpressible mystical experience of Revelation proclaimed by Rahner. Walter Kasper used Rahner’s ideas when he pointed to scientific rigour, ecclesiasticism and willingness to be opened to the world as main features of modern theology. At the same time, he considers it impossible to reject metaphysics and to reduce theology to a number of disparate academic studies. He sees the Holy Scriptures and church tradition as the essential foundation for systematic theology and argues that it is necessary to restore the balance between the freedom of theological investigation and the hierarchical control of Church magisterium

  2. Experimental Investigations on Microshock Waves and Contact Surfaces

    Kai, Yun; Garen, Walter; Teubner, Ulrich

    2018-02-01

    The present work reports on progress in the research of a microshock wave. Because of the lack of a good understanding of the propagation mechanism of the microshock flow system (shock wave, contact surface, and boundary layer), the current work concentrates on measuring microshock flows with special attention paid to the contact surface. A novel setup involving a glass capillary (with a 200 or 300 μ m hydraulic diameter D ) and a high-speed magnetic valve is applied to generate a shock wave with a maximum initial Mach number of 1.3. The current work applies a laser differential interferometer to perform noncontact measurements of the microshock flow's trajectory, velocity, and density. The current work presents microscale measurements of the shock-contact distance L that solves the problem of calculating the scaling factor Sc =Re ×D /(4 L ) (introduced by Brouillette), which is a parameter characterizing the scaling effects of shock waves. The results show that in contrast to macroscopic shock waves, shock waves at the microscale have a different propagation or attenuation mechanism (key issue of this Letter) which cannot be described by the conventional "leaky piston" model. The main attenuation mechanism of microshock flow may be the ever slower moving contact surface, which drives the shock wave. Different from other measurements using pressure transducers, the current setup for density measurements resolves the whole microshock flow system.

  3. Fragrance contact allergy

    Johansen, Jeanne D

    2003-01-01

    in the same products. This means that it is difficult to avoid exposure, as products labelled as 'fragrance free' have also been shown to contain fragrance ingredients, either because of the use of fragrance ingredients as preservatives or masking perfumes, or the use of botanicals. About 2500 different...... fragrance ingredients are currently used in the composition of perfumes and at least 100 of these are known contact allergens. Therefore, it is advisable to supplement standard patch testing with the patient's own stay-on cosmetic products, as well as the fragrance chemical hydroxyisohexyl-3-cyclohexane...... carboxaldehyde, which on its own gives responses in 1-3% of tested patients. The focus in recent years on the ingredients of the fragrance mix will probably result in the fragrance industry changing the composition of perfumes, and thus make the current diagnostic test less useful. New diagnostic tests are under...

  4. A mechanical-electrical finite element method model for predicting contact resistance between bipolar plate and gas diffusion layer in PEM fuel cells

    Lai, Xinmin; Liu, Dong' an; Peng, Linfa [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Ni, Jun [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)

    2008-07-15

    Contact resistance between the bipolar plate (BPP) and the gas diffusion layer (GDL) plays a significant role on the power loss in a proton exchange membrane (PEM) fuel cell. There are two types of contact behavior at the interface of the BPP and GDL, which are the mechanical one and the electrical one. Furthermore, the electrical contact behavior is dependent on the mechanical one. Thus, prediction of the contact resistance is a coupled mechanical-electrical problem. The current FEM models for contact resistance estimation can only simulate the mechanical contact behavior and moreover they are based on the assumption that the contact surface is equipotential, which is not the case in a real BPP/GDL assembly due to the round corner and margin of the BPP. In this study, a mechanical-electrical FEM model was developed to predict the contact resistance between the BPP and GDL based on the experimental interfacial contact resistivity. At first, the interfacial contact resistivity was obtained by experimentally measuring the contact resistance between the GDL and a flat graphite plate of the same material and processing conditions as the BPP. Then, with the interfacial contact resistivity, the mechanical and electrical contact behaviors were defined and the potential distribution of the BPP/GDL assembly was analyzed using the mechanical-electrical FEM model. At last, the contact resistance was calculated according to the potential drop and the current of the contact surface. The numerical results were validated by comparing with those of the model reported previously. The influence of the round corner of the BPP on the contact resistance was also studied and it is found that there exists an optimal round corner that can minimize the contact resistance. This model is beneficial in understanding the mechanical and electrical contact behaviors between the BPP and GDL, and can be used to predict the contact resistance in a new BPP/GDL assembly. (author)

  5. [Current state of training in pharmacy education using a problem-based learning/tutorial model with simulated patients and standardized patients at National University Corporation].

    Irie, Tetsumi; Nitta, Atsumi; Akaike, Akinori

    2012-01-01

    Simulated/standardized patient-based (SP) education and problem-based learning (PBL) tutorial education become a powerful tool to heighten the pharmacy students' will to learn in order to cultivate the responsibility to contribute to public health and welfare as a clinical professional and to facilitate students' competences to solve problems by themselves. What this program is trying to do is: 1) to establish the system to train, educate and supply SP who are effective in the training and education of pharmacy students in close cooperation with the medical schools and their affiliated hospitals; 2) to improve the quality of the current PBL tutorial education and thereby establish it as an advanced education program in the education of senior students. We carried out the questionnaire to National University Corporation which establishes a school of pharmacy, as to the training and education of SP. The analysis of the answers to the questionnaire revealed the present status of SP in the Pharmaceutical Objective Structured Clinical Examination (OSCE) in the Pharmaceutical Common Achievement Test, and the existence of the problems on how to standardize SP as well as how to cover such expenses. Furthermore, the activity of the first year consisted of the exchange and sharing of information regarding the existing method of training and education of SP and PBL tutorial education and the identification of the problems to be solved in order to improve the quality of the educational program.

  6. Contact Dermatitis in Pediatrics.

    Pelletier, Janice L; Perez, Caroline; Jacob, Sharon E

    2016-08-01

    Contact dermatitis is an umbrella term that describes the skin's reaction to contacted noxious or allergenic substances. The two main categories of contact dermatitis are irritant type and allergic type. This review discusses the signs, symptoms, causes, and complications of contact dermatitis. It addresses the testing, treatment, and prevention of contact dermatitis. Proper management of contact dermatitis includes avoidance measures for susceptible children. Implementation of a nickel directive (regulating the use of nickel in jewelry and other products that come into contact with the skin) could further reduce exposure to the most common allergens in the pediatric population. [Pediatr Ann. 2016;45(8):e287-e292.]. Copyright 2016, SLACK Incorporated.

  7. The contact sport of rough surfaces

    Carpick, Robert W.

    2018-01-01

    Describing the way two surfaces touch and make contact may seem simple, but it is not. Fully describing the elastic deformation of ideally smooth contacting bodies, under even low applied pressure, involves second-order partial differential equations and fourth-rank elastic constant tensors. For more realistic rough surfaces, the problem becomes a multiscale exercise in surface-height statistics, even before including complex phenomena such as adhesion, plasticity, and fracture. A recent research competition, the “Contact Mechanics Challenge” (1), was designed to test various approximate methods for solving this problem. A hypothetical rough surface was generated, and the community was invited to model contact with this surface with competing theories for the calculation of properties, including contact area and pressure. A supercomputer-generated numerical solution was kept secret until competition entries were received. The comparison of results (2) provides insights into the relative merits of competing models and even experimental approaches to the problem.

  8. Children with atopic dermatitis may have unacknowledged contact allergies contributing to their skin symptoms

    Simonsen, A B; Johansen, J D; Deleuran, M

    2017-01-01

    BACKGROUND: Whether children with atopic dermatitis have an altered risk of contact allergy than children without atopic dermatitis is frequently debated and studies have been conflicting. Theoretically, the impaired skin barrier in AD facilitates the penetration of potential allergens and several...... authors have highlighted the risk of underestimating and overlooking contact allergy in children with atopic dermatitis. OBJECTIVE: To determine the prevalence of contact allergy in Danish children with atopic dermatitis and explore the problem of unacknowledged allergies maintaining or aggravating...... one contact allergy that was relevant to the current skin symptoms. The risk of contact allergy was significantly correlated to the severity of atopic dermatitis. Metals and components of topical skin care products were the most frequent sensitizers. CONCLUSION: Patch testing is relevant...

  9. Current Titles

    Various

    2006-06-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Jane Cavlina, Administrator, at 510/486-6036.

  10. Basic technology of high-Tc superconductors. Project: Preparation, microstructure, contacts

    Arlt, G.; Bonnenberg, D.; Kliem, H.

    1991-01-01

    By conventional mixed oxide sintering technique some hundred samples of polycrystalline BYaCuO were prepared. Their physical properties were measured here and in some other research organizations. We investigated mainly: The origin of domain configuration, the contact resistances metal-superconductor, the critical current. All problems were solved satisfactorily. (orig.) With 30 refs [de

  11. American Contact Dermatitis Society Contact Allergy Management Program: An Epidemiologic Tool to Determine Relative Prevalence of Contact Allergens.

    Scheman, Andrew; Severson, David

    2016-01-01

    Data on the prevalence of contact allergy in North America are currently reported by groups of academic contact allergy specialists at select academic centers. Sampling of data from numerous centers across North America, including practices performing more limited patch testing, would provide a broader perspective of contact allergen prevalence in North America. The American Contact Dermatitis Society Contact Allergy Management Program is an ideal tool for collection of epidemiologic data regarding contact allergy prevalence in North America. The aim of the study was to identify the relative prevalence of contact allergy to common contact allergens in North America. Mapping of Contact Allergy Management Program (CAMP) data was performed to allow analysis of how frequently searches were performed for various contact allergens. The number of searches performed for specific allergens provides a measure of the relative prevalence of contact allergy to these allergens. The top 35 allergens for the period from November 18, 2012 to November 18, 2013 are reported. Although these data are useful, specific recommendations for minor alterations to CAMP are discussed, which will allow future CAMP data to be stratified and more powerful. With minor modifications, CAMP can provide a quantum leap in the reporting of contact allergy epidemiologic data in North America.

  12. Coordinate transformation in the model of long Josephson contacts: geometrically equivalent contacts

    Semerdzhieva, E.G.; Boyadzhiev, T.L.; ); Shukrinov, Yu.M.; Physical Technical Institute Dushanbe, 734063

    2005-01-01

    The transition from model of long Josephson variable-width contact to the contact model with coordinate-dependent Josephson current amplitude is realized by transforming the coordinates. This sets up a correspondence between Josephson contacts of variable width and quasi-one-dimensional contacts of variable thickness barrier layer. It is shown, that for contacts of exponentially varying width the barrier layer of the corresponding quasi-one-dimensional contact contains the distributed resistive inhomogeneity which is an attractor to magnetic flux vortices. With numerical experiments, a 'critical current-magnetic field' dependence for a resistive microinhomogeneity Josephson contact was plotted, and its comparison with the critical curve for a contact of exponentially varying width was made. Thus, this demonstrates that the distributed inhomogeneity may be replaced by a local one at the JC end what technologically, may offer definite advantages

  13. Contact mechanics: contact area and interfacial separation from small contact to full contact

    Yang, C; Persson, B N J

    2008-01-01

    We present a molecular dynamics study of the contact between a rigid solid with a randomly rough surface and an elastic block with a flat surface. The numerical calculations mainly focus on the contact area and the interfacial separation from small contact (low load) to full contact (high load). For a small load the contact area varies linearly with the load and the interfacial separation depends logarithmically on the load. For a high load the contact area approaches the nominal contact area (i.e. complete contact), and the interfacial separation approaches zero. The numerical results have been compared with analytical theory and experimental results. They are in good agreement with each other. The present findings may be very important for soft solids, e.g. rubber, or for very smooth surfaces, where complete contact can be reached at moderately high loads without plastic deformation of the solids

  14. Direct contact condensation in packed beds

    Li, Yi; Klausner, James F.; Mei, Renwei; Knight, Jessica [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2006-12-15

    A diffusion driven desalination process was recently described where a very effective direct contact condenser with a packed bed is used to condense water vapor out of an air/vapor mixture. A laboratory scale direct contact condenser has been fabricated as a twin tower structure with two stages, co-current and countercurrent. Experiments have been operated in each stage with respective saturated air inlet temperatures of 36, 40 and 43{sup o}C. The temperature and humidity data have been collected at the inlet and exit of the packed bed for different water to air mass flow ratios that vary between 0 and 2.5. A one-dimensional model based on conservation principles has been developed, which predicts the variation of temperature, humidity, and condensation rate through the condenser stages. Agreement between the model and experiments is very good. It is observed that the countercurrent flow stage condensation effectiveness is significantly higher than that for the co-current stage. The condensation heat and mass transfer rates were found to decrease when water blockages occur within the packed bed. Using high-speed digital cinematography, it was observed that this problem can occur at any operating condition, and is dependent on the packing surface wetting characteristics. This observation is used to explain the requirement for two different empirical constants, depending on packing diameter, suggested by Onda for the air side mass transfer coefficient correlation. (author)

  15. A survey of wheel-rail contact models for rail vehicles

    Meymand, Sajjad Z.; Keylin, Alexander; Ahmadian, Mehdi

    2016-03-01

    Accurate and efficient contact models for wheel-rail interaction are essential for the study of the dynamic behaviour of a railway vehicle. Assessment of the contact forces and moments, as well as contact geometry provide a fundamental foundation for such tasks as design of braking and traction control systems, prediction of wheel and rail wear, and evaluation of ride safety and comfort. This paper discusses the evolution and the current state of the theories for solving the wheel-rail contact problem for rolling stock. The well-known theories for modelling both normal contact (Hertzian and non-Hertzian) and tangential contact (Kalker's linear theory, FASTSIM, CONTACT, Polach's theory, etc.) are reviewed. The paper discusses the simplifying assumptions for developing these models and compares their functionality. The experimental studies for evaluation of contact models are also reviewed. This paper concludes with discussing open areas in contact mechanics that require further research for developing better models to represent the wheel-rail interaction.

  16. Keep Contacts Clean (A Cup of Health with CDC)

    Contact lenses can be a comfortable and convenient alternative to traditional eye glasses, but without proper care, they can cause severe eye problems. In this podcast, Sarah Collier discusses the importance of proper maintenance of contact lenses.

  17. Colored Contact Lens Dangers

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... new application of artificial intelligence shows whether a patient’s eyes point to high blood pressure or risk ...

  18. Colored Contact Lens Dangers

    Full Text Available ... Costume Contacts May Contain Chemicals Harmful to Eyes Four Ways Over-the-Counter Costume Contact Lenses Can ... was in severe pain and on medication for four weeks, and couldn't see well enough to ...

  19. Colored Contact Lens Dangers

    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  20. Contact Angle Goniometer

    Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

  1. Colored Contact Lens Dangers

    Full Text Available ... like a suction cup." Halloween is a popular time for people to use colored contact lenses to ... wear costume contact lenses for Halloween or any time of year, follow these guidelines: Get an eye ...

  2. Colored Contact Lens Dangers

    Full Text Available ... glow-in-the-dark lizard lenses, costume contacts can certainly add a spooky, eye-popping touch. But ... consideration as a standard contact lens because they can be purchased over-the-counter or on the ...

  3. Colored Contact Lens Dangers

    Full Text Available ... contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are considering ... Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at ...

  4. Colored Contact Lens Dangers

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  5. Dermatitis, contact (image)

    This picture shows a skin inflammation (dermatitis) caused by contact with a material that causes an allergic reaction in this person. Contact dermatitis is a relatively common condition, and can be caused ...

  6. Colored Contact Lens Dangers

    Full Text Available ... the United States. All contact lenses are medical devices that require a prescription and proper fitting by an eye-care professional. Retailers that sell contacts without a ...

  7. Colored Contact Lens Dangers

    Full Text Available ... prescription. Follow the contact lens care directions for cleaning, disinfecting, and wearing the lenses. Never share contact ... with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  8. Sand Particles Impact on the Tribological Behavior of Sliding Contact

    Aldajah Saud

    2016-01-01

    Full Text Available Lubricant contaminants cause severe problems to machines. Substantial research has been conducted to study the impact of such contaminates on the tribological performance of lubricated contacts. The primary goal of such studies is to find solutions to avoid the dirtiest cause of damaging machines’ parts and to reduce energy consumption and maintenance costs. The current study investigates the tribological behavior of contaminated lubricated contacts; the contaminants considered in this research are sand particles. The effect of the sand particles concentration levels on friction and wear of a tribological system under sliding contact was studied. Three different concentration levels were tested; 5%, 10% and 15%.The experimental program was carried out using an in-house built ball on disc machine at room temperature, constant normal load, constant speed, constant running time and constant travelling distance. Results showed that both friction coefficient and wear volume of the contacting surfaces are dependent on the concentration level of the sand particles. Both friction coefficient and wear volume increased by increasing the sand particles concentration. SEM was utilized to study the wear mechanisms of the contacting surfaces, it was found that the dominant wear mechanism in all cases was abrasive wear.

  9. Contact Lens Risks

    ... There is a risk of eye infection from bacteria in swimming pool water, hot tubs, lakes and the ocean Replace your contact lens storage case every 3 months or as directed by your eye care professional. Other Risks of Contact Lenses Other risks of contact lenses include pink eye ( ...

  10. Hydrogenation of passivated contacts

    Nemeth, William; Yuan, Hao-Chih; LaSalvia, Vincenzo; Stradins, Pauls; Page, Matthew R.

    2018-03-06

    Methods of hydrogenation of passivated contacts using materials having hydrogen impurities are provided. An example method includes applying, to a passivated contact, a layer of a material, the material containing hydrogen impurities. The method further includes subsequently annealing the material and subsequently removing the material from the passivated contact.

  11. Mixed Lubricated Line Contacts

    Faraon, I.C.

    2005-01-01

    The present work deals with friction in mixed lubricated line contacts. Components in systems are becoming smaller and due to, for instance power transmitted, partial contact may occur. In industrial applications, friction between the moving contacting surfaces cannot be avoided, therefore it is

  12. New Cosmetic Contact Allergens

    An Goossens

    2015-02-01

    Full Text Available Allergic and photo-allergic contact dermatitis, and immunologic contact urticaria are potential immune-mediated adverse effects from cosmetics. Fragrance components and preservatives are certainly the most frequently observed allergens; however, all ingredients must be considered when investigating for contact allergy.

  13. A case of pneumonia and sepsis in cirrhosis as paradigm of the problems in the management of bacterial infections in cirrhosis and of the limitations of current knowledge

    Manuel Tufoni

    2013-09-01

    Full Text Available Bacterial infections are a major problem in the management of liver cirrhosis. They represent the first precipitating cause of death since patients with cirrhosis carry an increased risk of sepsis, sepsis-induced organ failure and death. Although the clinical presentation is often misleading, the presence of bacterial infection should always be actively searched and ruled out with certainty whenever a cirrhotic patient is admitted to the hospital with an acute clinical deterioration. Major changes in the epidemiology of bacterial infections have also occurred in the last decade making the choice of empirical antibiotic therapy a challenge. We report a paradigmatic case of a 54-year old man with hepatitis C-related cirrhosis admitted to the hospital for worsening of his ascites and onset of hepatic encephalopathy, an excellent example for the difficulties of management of sepsis in cirrhosis and the limits of current knowledge.

  14. Continuum model of tensile fracture of metal melts and its application to a problem of high-current electron irradiation of metals

    Mayer, Alexander E.; Mayer, Polina N.

    2015-01-01

    A continuum model of the metal melt fracture is formulated on the basis of the continuum mechanics and theory of metastable liquid. A character of temperature and strain rate dependences of the tensile strength that is predicted by the continuum model is verified, and parameters of the model are fitted with the use of the results of the molecular dynamics simulations for ultra-high strain rates (≥1–10/ns). A comparison with experimental data from literature is also presented for Al and Ni melts. Using the continuum model, the dynamic tensile strength of initially uniform melts of Al, Cu, Ni, Fe, Ti, and Pb within a wide range of strain rates (from 1–10/ms to 100/ns) and temperatures (from melting temperature up to 70–80% of critical temperature) is calculated. The model is applied to numerical investigation of a problem of the high-current electron irradiation of Al, Cu, and Fe targets

  15. Contact Lenses for Color Blindness.

    Badawy, Abdel-Rahman; Hassan, Muhammad Umair; Elsherif, Mohamed; Ahmed, Zubair; Yetisen, Ali K; Butt, Haider

    2018-06-01

    Color vision deficiency (color blindness) is an inherited genetic ocular disorder. While no cure for this disorder currently exists, several methods can be used to increase the color perception of those affected. One such method is the use of color filtering glasses which are based on Bragg filters. While these glasses are effective, they are high cost, bulky, and incompatible with other vision correction eyeglasses. In this work, a rhodamine derivative is incorporated in commercial contact lenses to filter out the specific wavelength bands (≈545-575 nm) to correct color vision blindness. The biocompatibility assessment of the dyed contact lenses in human corneal fibroblasts and human corneal epithelial cells shows no toxicity and cell viability remains at 99% after 72 h. This study demonstrates the potential of the dyed contact lenses in wavelength filtering and color vision deficiency management. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Effect of Contact Pressure on the Resistance Contact Value and Temperature Changes in Copper Busbar Connection

    Agus Risdiyanto

    2012-12-01

    Full Text Available This paper discussed the influence of tightness or contacts pressure on copper busbar joints to determine changes in the value of the initial contact resistance and the maximum temperature at the joint due to high current load. The test sample was copper busbar 3 x 30 mm with configuration of bolted overlapping joint. Increasing contact pressure at the joint was measured to find out its effect on the value of contact resistance. The applied pressure was 6 to 36 MPa. Procedure of contact resistance measurement refer to the ASTM B539 standard using four-wire method. The sample subsequently loaded with the current of 350 A for 60 minutes and the maximum temperature at the joint was measured. The result showed that increasing contact pressure at the busbar joint will reduce the contact resistance and maximum temperature. The increase of contact pressure from 6 to 30 MPa causes decreasing contact resistance from 16 μΩ to 11 μΩ. Further increasing of contact pressure more than 30 MPa did not affect the contact resistance significantly. The lowest temperatur of busbar joint of 54°C was reached at a contact pressure of 36 Mpa.

  17. Mechanoluminescent Contact Type Sensor

    A. K. Yefremov

    2017-01-01

    Full Text Available Mechanoluminescent sensing elements convert mechanical stress into optical radiation. Advantages of such sensors are the ability to generate an optical signal, solid-state, simple structure, and resistance to electromagnetic interference. Mechanoluminescent sensor implementations can possess the concentrated and distributed sensitivity, thereby allowing us to detect the field of mechanical stresses distributed across the area and in volume. Most modern semiconductor photo-detectors can detect mechanoluminescent radiation, so there are no difficulties to provide its detection when designing the mechanoluminescent sensing devices. Mechanoluminescent substances have especial sensitivity to shock loads, and this effect can be used to create a fuse the structure of which includes a target contact type sensor with a photosensitive actuator. The paper briefly describes the theoretical basics of mechanoluminiscence: a light signal emerges from the interaction of crystalline phosphor luminescence centers with electrically charged dislocations, moving due to the deformation of the crystal. A mathematical model of the mechanoluminescent conversion is represented as a functional interaction between parameters of the mechanical shock excitation and the sensor light emission. Examples of computing the optical mechanoluminescent output signal depending on the duration and peak level of impulse load are given. It is shown that the luminous flux, generated by mechanoluminescent sensing element when there is an ammunition-target collision causes the current emerging in photo-detector (photodiode that is sufficient for a typical actuator of the fuse train to operate. The potential possibility to create a contact target type sensor based on the light-sensitive mechanoluminescent sensor was proved by the calculation and simulation results.

  18. CONTACT RESISTANCE MODELING

    S. V. LOSKUTOV

    2018-05-01

    Full Text Available Purpose. To determine the contribution of the real contact spots distribution in the total conductivity of the conductors contact. Methodology. The electrical contact resistance research was carried out on models. The experimental part of this work was done on paper with a graphite layer with membranes (the first type and conductive liquids with discrete partitions (the second type. Findings. It is shown that the contact electrical resistance is mainly determined by the real area of metal contact. The experimental dependence of the electrical resistance of the second type model on the distance between the electrodes and the potential distribution along the sample surface for the first type model were obtained. The theoretical model based on the principle of electric field superposition was considered. The dependences obtained experimentally and calculated by using the theoretical model are in good agreement. Originality. The regularity of the electrical contact resistance formation on a large number of membranes was researched for the first time. A new model of discrete electrical contact based on the liquid as the conducting environment with nuclear membrane partitions was developed. The conclusions of the additivity of contact and bulk electrical resistance were done. Practical value. Based on these researches, a new experimental method of kinetic macroidentation that as a parameter of the metal surface layer deformation uses the real contact area was developed. This method allows to determine the value of average contact stresses, yield point, change of the stress on the depth of deformation depending on the surface treatment.

  19. [Contact glass tonometer].

    Dekker, P W; Kanngiesser, H; Robert, Y C

    1996-05-01

    This paper presents a tonometer built into a contactlens, which allows to measure the eye-pressure and to perform ophthalmoscopy at the same time. Artificially induced changes of the eye-pressure and their influence on the visible fundus can now be checked simultaneously. The contactlens-tonometer (CGT) also is able to record continuously the pulse-curve, which can indicate any circulatory problem. So, the device is expected to give us additional diagnostic criteria of early glaucoma. Each ophthalmologyst in the field will be able to perform with this device a oculodynamometry in an easy way. By this it is possible to estimate the pressure-tolerance of the optic disk from glaucoma-patients. There have been taken some measurements on enucleated human eyes, comparing our device with a Statham-transducer in the vitreous. We found a good correlation. In a second step, we made measurements (65) on healthy volunteers, comparing the device with Perkins-Tonometry. We found a correlation (R = 0.58). The error of the measurements was about +/- 3 mm Hg. Considering both, the deviation of the Perkins-Tonometer with which our results were compared, and the fact of a good correlation (R = 0.999) in the study with the enucleated human eyes, we found that the contact-lens-tonometer measures the intraocular pressure exactly. In future studies, we want to analyze the dynamic component of the measurements.

  20. Contact and symplectic topology

    Colin, Vincent; Stipsicz, András

    2014-01-01

    Symplectic and contact geometry naturally emerged from the mathematical description of classical physics. The discovery of new rigidity phenomena and properties satisfied by these geometric structures launched a new research field worldwide. The intense activity of many European research groups in this field is reflected by the ESF Research Networking Programme "Contact And Symplectic Topology" (CAST). The lectures of the Summer School in Nantes (June 2011) and of the CAST Summer School in Budapest (July 2012) provide a nice panorama of many aspects of the present status of contact and symplectic topology. The notes of the minicourses offer a gentle introduction to topics which have developed in an amazing speed in the recent past. These topics include 3-dimensional and higher dimensional contact topology, Fukaya categories, asymptotically holomorphic methods in contact topology, bordered Floer homology, embedded contact homology, and flexibility results for Stein manifolds.

  1. European Surveillance System on Contact Allergies (ESSCA)

    Uter, W; Amario-Hita, J C; Balato, A

    2017-01-01

    BACKGROUND: Contact allergy is a common condition and can severely interfere with daily life or professional activities. Due to changes in exposures, such as introduction of new substances, new products or formulations and regulatory intervention, the spectrum of contact sensitization changes....... OBJECTIVE: To evaluate the current spectrum of contact allergy to allergens present in the European baseline series (EBS) across Europe. METHODS: Retrospective analysis of data collected by the European Surveillance System on Contact Allergies (ESSCA, www.essca-dc.org) in consecutively patch-tested patients......, 2013/14, in 46 departments in 12 European countries. RESULTS: Altogether, 31 689 patients were included in the analysis. Compared to a similar analysis in 2004, the prevalence of contact allergy to methylisothiazolinone went up to around 20% in several departments. In comparison, contact allergy...

  2. Introduction to contact mechanics

    Fischer-Cripps, Anthony C

    2000-01-01

    Contact mechanics deals with the elastic or plastic contact between two solid objects, and is thus intimately connected with such topics as fracture, hardness, and elasticity.This text, intended for advanced undergraduates, begins with an introduction to the mechanical properties of materials, general fracture mechanics, and fractures in brittle solids.This is followed by a detailed discussion of stresses and the nature of elastic and elastic-plastic contact.

  3. Colored Contact Lens Dangers

    Full Text Available ... also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial ...

  4. Colors and contact dermatitis.

    Bonamonte, Domenico; Foti, Caterina; Romita, Paolo; Vestita, Michelangelo; Angelini, Gianni

    2014-01-01

    The diagnosis of skin diseases relies on several clinical signs, among which color is of paramount importance. In this review, we consider certain clinical presentations of both eczematous and noneczematous contact dermatitis in which color plays a peculiar role orientating toward the right diagnosis. The conditions that will be discussed include specific clinical-morphologic subtypes of eczematous contact dermatitis, primary melanocytic, and nonmelanocytic contact hyperchromia, black dermographism, contact chemical leukoderma, and others. Based on the physical, chemical, and biologic factors underlying a healthy skin color, the various skin shades drawing a disease picture are thoroughly debated, stressing their etiopathogenic origins and histopathologic aspects.

  5. Current srate and problems in Japanese petroleum development. ; International trends in petroleum development and problems in Japanese devepment business. Waga kuni sekiyu kaihatsu no genjyo to mondai ten. ; Sekiyu kaihatsu no kokusai doko to waga kuni kaihatsu jigyo no kasai

    1991-11-05

    Petroleum production and its supply and demand require ever closer coordinations among the countries involved. On the other hand, however, there a large number of difficult questions as the problems of global environmental pollution and greenhouse effects increase their seriousness and the economic resources in the petroleum business become scarcer. This paper describes the current state of the Japanese petroleum development, the necessity of spontaneous petroleum development, the international trends in the petroleum development business, and the tasks for Japan in the petroleum development business. Japan is a late comer in the petroleum development business. There are such difficulties as sizes of oil fields being discoverd are becoming smaller, the natural conditions in development target areas are getting severer, and the economic effects are inferior. Japan, whose petroleum self-supply rate is about 0.3%, whose petroleum dependency is heightening as a result of increase in nuclear power generation, and who is the third largest petroleum consuming country next to the U.S.A and Soviet, must use efficiently her financial and technical powers to vitalize her spontaneous petroleum development. Japan has a duty to contribute to the world {prime}s future stabilized supply of oil. The Japanese Government has launched the five-year fund development plan to perform basic surveys for ail in the north-east part of the Japan Sea and the pacific Ocean.

  6. Computational contact and impact mechanics fundamentals of modeling interfacial phenomena in nonlinear finite element analysis

    Laursen, Tod A

    2003-01-01

    This book comprehensively treats the formulation and finite element approximation of contact and impact problems in nonlinear mechanics. Intended for students, researchers and practitioners interested in numerical solid and structural analysis, as well as for engineers and scientists dealing with technologies in which tribological response must be characterized, the book includes an introductory but detailed overview of nonlinear finite element formulations before dealing with contact and impact specifically. Topics encompassed include the continuum mechanics, mathematical structure, variational framework, and finite element implementations associated with contact/impact interaction. Additionally, important and currently emerging research topics in computational contact mechanics are introduced, encompassing such topics as tribological complexity, conservative treatment of inelastic impact interaction, and novel spatial discretization strategies.

  7. Colored Contact Lens Dangers

    Full Text Available ... eye-care professional. Retailers that sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. "Many of the lenses found online or in beauty salons, novelty shops or in pop-up ... contact lenses from a retailer that does not ask for a prescription. ...

  8. Electric contact arcing

    Cuthrell, R.E.

    1976-01-01

    Electrical contacts must function properly in many types of components used in nuclear weapon systems. Design, application, and testing of these components require detailed knowledge of chemical and physical phenomena associated with stockpile storage, stockpile testing, and operation. In the past, investigation of these phenomena has led to significant discoveries on the effects of surface contaminants, friction and wear, and the mechanics of closure on contact performance. A recent investigation of contact arcing phenomena which revealed that, preceding contact closure, arcs may occur at voltages lower than had been previously known is described. This discovery is important, since arcing may damage contacts, and repetitive testing of contacts performed as part of a quality assurance program might produce cumulative damage that would yield misleading life-test data and could prevent proper operation of the contacts at some time in the future. This damage can be avoided by determining the conditions under which arcing occurs, and ensuring that these conditions are avoided in contact testing

  9. Colored Contact Lens Dangers

    Full Text Available ... Get follow up exams with your eye care provider. If you notice redness, swelling, excessive discharge, pain or discomfort from wearing contact lenses, remove the lenses and seek immediate medical attention from an ophthalmologist. Related resources: Learn how to properly care for contact lenses . ...

  10. Sciences & Nature: Contact

    Principal Contact. Ehouan Etienne Ehile Professor University of Abobo-Adjamé 02 BP 801 Abidjan 02. Phone: (+225) 2030 4201. Fax: (+225) 2030 4203. Email: eh_ehile@yahoo.fr. Support Contact. Irie Zoro Bi Email: banhiakalou@yahoo.fr. ISSN: 1812-0741. AJOL African Journals Online. HOW TO USE AJOL.

  11. Contact Us | DOepatents

    advance. Your help is appreciated. Contact us by email Email doepatentscomments@osti.gov NOTE: Email us by phone Phone Phone (865) 241-5275 Contact us in writing Mail U.S. Department of Energy Office of non-federal websites. Their policies may differ from this site. Javascript Not Enabled Email Link

  12. Colored Contact Lens Dangers

    Full Text Available ... eye-care team . Consumer warning about the improper use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are considering buying approved by the FDA? Check the FDA's database of approved contact lenses . Related Stories Prevent Infection ...

  13. Contact dermatitis. A review

    Andersen, Klaus Ejner; Benezra, C; Burrows, D

    1987-01-01

    In recent years, there has been a dramatic rise in our understanding of contact dermatitis. This paper is a review of our knowledge of the mechanisms involved in contact dermatitis and related phenomena, the investigation of these events and the emergence of significant new allergens during...

  14. Contact Hamiltonian mechanics

    Bravetti, Alessandro, E-mail: alessandro.bravetti@iimas.unam.mx [Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, A. P. 70543, México, DF 04510 (Mexico); Cruz, Hans, E-mail: hans@ciencias.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A. P. 70543, México, DF 04510 (Mexico); Tapias, Diego, E-mail: diego.tapias@nucleares.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, A.P. 70543, México, DF 04510 (Mexico)

    2017-01-15

    In this work we introduce contact Hamiltonian mechanics, an extension of symplectic Hamiltonian mechanics, and show that it is a natural candidate for a geometric description of non-dissipative and dissipative systems. For this purpose we review in detail the major features of standard symplectic Hamiltonian dynamics and show that all of them can be generalized to the contact case.

  15. Contact Quality in Participation

    Simonsen, Jesper; Jensen, Olav Storm

    2016-01-01

    We investigate the concept of participation from the perspective of quality of the contact in the communicative interactions between participants. We argue for the need for an academic-personal competence that qualifies the human contact central in all Participatory Design (PD) activities as a way...

  16. Nigerian Food Journal: Contact

    Nigerian Food Journal. ... Nigerian Food Journal: Contact. Journal Home > About the Journal > Nigerian Food Journal: Contact. Log in or Register to get access to full text downloads. ... Mailing Address. Department of Food Science and Technology University of Agriculture, Makurdi, Nigeria ...

  17. Colored Contact Lens Dangers

    Full Text Available ... like a suction cup." Halloween is a popular time for people to use colored contact lenses to enhance their costumes. From ... MD, professor of ophthalmology at Case Western Reserve University in Cleveland. "This is far ... Use Facts About Colored Contacts and Halloween Safety Colored ...

  18. Noneczematous Contact Dermatitis

    Foti, Caterina; Vestita, Michelangelo; Angelini, Gianni

    2013-01-01

    Irritant or allergic contact dermatitis usually presents as an eczematous process, clinically characterized by erythematoedematovesicous lesions with intense itching in the acute phase. Such manifestations become erythematous-scaly as the condition progresses to the subacute phase and papular-hyperkeratotic in the chronic phase. Not infrequently, however, contact dermatitis presents with noneczematous features. The reasons underlying this clinical polymorphism lie in the different noxae and contact modalities, as well as in the individual susceptibility and the various targeted cutaneous structures. The most represented forms of non-eczematous contact dermatitis include the erythema multiforme-like, the purpuric, the lichenoid, and the pigmented kinds. These clinical entities must obviously be discerned from the corresponding “pure” dermatitis, which are not associated with contact with exogenous agents. PMID:24109520

  19. Anomalous Temperature Dependence in Metal-Black Phosphorus Contact.

    Li, Xuefei; Grassi, Roberto; Li, Sichao; Li, Tiaoyang; Xiong, Xiong; Low, Tony; Wu, Yanqing

    2018-01-10

    Metal-semiconductor contact has been the performance limiting problem for electronic devices and also dictates the scaling potential for future generation devices based on novel channel materials. Two-dimensional semiconductors beyond graphene, particularly few layer black phosphorus, have attracted much attention due to their exceptional electronic properties such as anisotropy and high mobility. However, due to its ultrathin body nature, few layer black phosphorus-metal contact behaves differently than conventional Schottky barrier (SB) junctions, and the mechanisms of its carrier transport across such a barrier remain elusive. In this work, we examine the transport characteristic of metal-black phosphorus contact under varying temperature. We elucidated the origin of apparent negative SB heights extracted from classical thermionic emission model and also the phenomenon of metal-insulator transition observed in the current-temperature transistor characteristic. In essence, we found that the SB height can be modulated by the back-gate voltage, which beyond a certain critical point becomes so low that the injected carrier can no longer be described by the conventional thermionic emission theory. The transition from transport dominated by a Maxwell-Boltzmann distribution for the high energy tail states, to that of a Fermi distribution by low energy Fermi sea electrons, is the physical origin of the observed metal-insulator transition. We identified two distinctive tunneling limited transport regimes in the contact: vertical and longitudinal tunneling.

  20. Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

    de Groot, Anton C; Flyvholm, Mari-Ann; Lensen, Gerda

    2009-01-01

    in the literature as formaldehyde-releasers, data are inadequate to consider them as such beyond doubt. Several (nomenclature) mistakes and outdated information are discussed. Formaldehyde and formaldehyde allergy are reviewed: applications, exposure scenarios, legislation, patch testing problems, frequency....... The frequency of contact allergy to formaldehyde is consistently higher in the USA (8-9%) than in Europe (2-3%). Patch testing with formaldehyde is problematic; the currently used 1% solution may result in both false-positive and false-negative (up to 40%) reactions. Determining the relevance of patch test...