WorldWideScience

Sample records for internal stresses due

  1. Axial contraction in etched optical fiber due to internal stress reduction.

    Science.gov (United States)

    Lim, Kok-Sing; Yang, Hang-Zhou; Chong, Wu-Yi; Cheong, Yew-Ken; Lim, Chin-Hong; Ali, Norfizah M; Ahmad, Harith

    2013-02-11

    When an optical fiber is dipped in an etching solution, the internal stress profile in the fiber varies with the fiber diameter. We observed a physical contraction as much as 0.2% in the fiber axial dimension when the fiber was reduced from its original diameter to ~6 µm through analysis using high resolution microscope images of the grating period of an etched FBG at different fiber diameters. This axial contraction is related to the varying axial stress profile in the fiber when the fiber diameter is reduced. On top of that, the refractive index of fiber core increases with reducing fiber diameter due to stress-optic effect. The calculated index increment is as much as 1.8 × 10(-3) at the center of fiber core after the diameter is reduced down to ~6 µm. In comparison with the conventional model that assumes constant grating period and neglects the variation in stress-induced index change in fiber core, our proposed model indicates a discrepancy as much as 3nm in Bragg wavelength at a fiber diameter of ~6 µm.

  2. Method to estimate the internal stresses due to moisture in wood using transmission properties of microwaves

    International Nuclear Information System (INIS)

    Takemura, T.; Taniguchi, T.

    2004-01-01

    The purpose of this paper is to offer a new method for detecting stress in wood due to moisture along the lines of a theory reported previously. According to the theory, the stress in wood could be estimated from the moisture content of the wood and the power voltage of a microwave moisture meter (i.e., attenuation of the projected microwave). This seems to suggest a possibility of utilizing microwaves in the field of stress detection. To develop such an idea, the stress formulas were initially modified to the form of an uni-variable function of power voltage, and the application method of the formulas to detection was tried. Finally, these results were applied to the data of sugi (Cryptomeria japonica) lumber in the previous experiment. The estimated strains showed fairly good agreement with those observed. It could be concluded from this study that the proposed method might be available for detecting stress in wood due to moisture

  3. Evaluation on ultrasonic examination methods applied to Ni-base alloy weld including cracks due to stress corrosion cracking found in BWR reactor internal

    International Nuclear Information System (INIS)

    Aoki, Takayuki; Kobayashi, Hiroyuki; Higuchi, Shinichi; Shimizu, Sadato

    2005-01-01

    A Ni-base alloy weld, including cracks due to stress corrosion cracking found in the reactor internal of the oldest BWR in Japan, Tsuruga unit 1, in 1999, was examined by three (3) types of UT method. After this examination, a depth of each crack was confirmed by carrying out a little excavation with a grinder and PT examination by turns until each crack disappeared. Then, the depth measured by the former method was compared with the one measured by the latter method. In this fashion, performances of the UT methods were verified. As a result, a combination of the three types of UT method was found to meet the acceptance criteria given by ASME Sec.XI Appendix VIII, Performance Demonstration for Ultrasonic Examination Systems-Supplement 6. In this paper, the results of the UT examination described above and their evaluation are discussed. (author)

  4. Internal dosimetric evaluation due to uranium aerosols

    International Nuclear Information System (INIS)

    Garcia Aguilar Juan; Delgado Avila Gustavo

    1991-01-01

    The present work has like object to carry out the internal dosimetric evaluation to the occupationally exposed personnel, due to the inhalation of aerosols of natural uranium and enriched in the pilot plant of nuclear fuel production of the National Institute of Nuclear Research

  5. T-stresses for internally cracked components

    International Nuclear Information System (INIS)

    Fett, T.

    1997-12-01

    The failure of cracked components is governed by the stresses in the vicinity of the crack tip. The singular stress contribution is characterised by the stress intensity factor K, the first regular stress term is represented by the so-called T-stress. T-stress solutions for components containing an internal crack were computed by application of the Bundary Collocation Method (BCM). The results are compiled in form of tables or approximative relations. In addition a Green's function of T-stresses is proposed for internal cracks which enables to compute T-stress terms for any given stress distribution in the uncracked body. (orig.) [de

  6. Pipe cracking due to thermal stresses produced by valve opening

    International Nuclear Information System (INIS)

    Sanchez Sarmiento, G.

    1982-01-01

    The thermal stresses produced in a tube whose internal surface is abrupt cooled during a valve opening so that the water volume increases linearly with time are studied. A general solution for these stresses and its stress intensity factors in terms of non-dimensional parameters is presented. (E.G.) [pt

  7. Increase of internal energy due to measurement

    International Nuclear Information System (INIS)

    Daboul, J.

    1991-01-01

    We argue that the internal energy E=(H) of a macroscopic system in thermal equilibrium must increase, if we measure an observable A which does not commute with the Hamiltonian H. We derive an expression for calculating a lower bound for this increase in E. We then generalize the above result, and show that under certain conditions the expectation value (C) of an observable C should increase by the measurement of another observable A, if A and C do not commute. (author)

  8. Isothermal martensitic transformation as an internal-stress-increasing process

    International Nuclear Information System (INIS)

    Liu, Y.; Xie, Z.L.; Haenninen, H.; Humbeeck, J. van; Pietikaeinen, J.

    1995-01-01

    Based on the results that the magnitude of the stabilization of retained austenite increases with increasing the amount of martensite transformed, it has been assumed that the martensitic transformation is accompanied with an increase in internal resisting stress which subsequently results in the stabilization of retained austenite. By simplifying this internal resisting stress to be a type of hydrostatic compressive stress acting on retained austenite due to surrounding martensite plates, a thermodynamical analysis for an isothermal martensitic transformation under applied hydrostatic pressure has been performed. The calculated results, to some extent, show a good agreement with the experimental data. (orig.)

  9. Internal stress control of boron thin film

    International Nuclear Information System (INIS)

    Satomi, N.; Kitamura, M.; Sasaki, T.; Nishikawa, M.

    1998-01-01

    The occurrence of stress in thin films has led to serious stability problems in practical use. We have investigated the stress in the boron films to find the deposition condition of the boron films with less stress. It was found that the stress in the boron film varies sufficiently from compressive to tensile stress, that is from -1.0 to 1.4 GPa, depending on the evaporation conditions, such as deposition rate and the substrate temperature. Hydrogen ion bombardment resulted in the enhancement of the compressive stress, possibly due to ion peening effect, while under helium ion bombardment, stress relief was observed. The boron film with nearly zero stress was obtained by the evaporation at a deposition rate of 0.5 nm s -1 and substrate temperature of 300 C. (orig.)

  10. Internal stress control of boron thin film

    Energy Technology Data Exchange (ETDEWEB)

    Satomi, N.; Kitamura, M.; Sasaki, T.; Nishikawa, M. [Osaka Univ., Suita (Japan). Graduate Sch. of Eng.

    1998-09-01

    The occurrence of stress in thin films has led to serious stability problems in practical use. We have investigated the stress in the boron films to find the deposition condition of the boron films with less stress. It was found that the stress in the boron film varies sufficiently from compressive to tensile stress, that is from -1.0 to 1.4 GPa, depending on the evaporation conditions, such as deposition rate and the substrate temperature. Hydrogen ion bombardment resulted in the enhancement of the compressive stress, possibly due to ion peening effect, while under helium ion bombardment, stress relief was observed. The boron film with nearly zero stress was obtained by the evaporation at a deposition rate of 0.5 nm s{sup -1} and substrate temperature of 300 C. (orig.) 12 refs.

  11. Evaluation of stress intensity factors due to welding residual stresses for circumferential cracked pipes

    International Nuclear Information System (INIS)

    Oh, Chang-Young; Kim, Yun-Jae; Oh, Young-Jin; Kim, Jong-Sung; Song, Tae-Kwang; Kim, Yong-Beum

    2013-01-01

    To investigate the applicability of existing methods to estimate stress intensity factors due to welding residual stresses, comparisons with finite element (FE) solutions are made for two types of generic welding residual stress profiles, generated by simulating repair welds. It is found that fitting residual stresses over the crack depth using third-order polynomials gives good estimates of stress intensity factors but fitting over the entire thickness can result in inaccurate estimates even with fourth-order polynomials. Noting that welding residual stresses are often determined from FE analyses, linearization of residual stresses to estimate stress intensity factors is proposed. Comparison with FE solutions shows good agreements. -- Highlights: ► Applicability of K estimation methods is investigated for welding residual stresses. ► Two types of generic residual stress profiles with repair welds are considered. ► Fitting residual stresses over the crack depth gives good estimates of K. ► A method to estimate K by linearising residual stress profiles is proposed

  12. Internal Stress in a Model Elasto-Plastic Fluid

    OpenAIRE

    Ooshida, Takeshi; Sekimoto, Ken

    2004-01-01

    Plastic materials can carry memory of past mechanical treatment in the form of internal stress. We introduce a natural definition of the vorticity of internal stress in a simple two-dimensional model of elasto-plastic fluids, which generates the internal stress. We demonstrate how the internal stress is induced under external loading, and how the presence of the internal stress modifies the plastic behavior.

  13. Internal stress analysis by acoustic polarimetry

    International Nuclear Information System (INIS)

    Rouge, Jean; Robert, Andre

    The associated improvements of acoustics and electronics allow the field of applications relative to the ultrasonic methods to be extended to the non destructive control of materials and structures. Thus, the acoustical polarimetry is a new method allowing the measurement in orientation and intensity of residual or induced internal stresses in metals or other materials [fr

  14. Studies of internal stress in diamond films prepared by DC plasma chemical vapour deposition

    International Nuclear Information System (INIS)

    Wang Wanlu; Gao Jinying; Liao Kejun; Liu Anmin

    1992-01-01

    The internal stress in diamond thin films deposited by DC plasma CVD was studied as a function of methane concentration and deposited temperature. Experimental results have shown that total stress in diamond thin films is sensitive to the deposition conditions. The results also indicate that the compressive stress can be explained in terms of amorphous state carbon and hydrogen, and tensile stress is ascribed to the grain boundary relaxation model due to high internal surface area and microstructure with voids

  15. A solar cycle of spacecraft anomalies due to internal charging

    Directory of Open Access Journals (Sweden)

    G. L. Wrenn

    Full Text Available It is important to appreciate how the morphology of internal charging of spacecraft systems, due to penetrating electrons, differs from that of the more common surface charging, due to electrons with lower energy. A specific and recurrent anomaly on a geostationary communication satellite has been tracked for ten years so that solar cycle and seasonal dependencies can be clearly established. Concurrent measurements of sunspot number, solar wind speed and 2-day >2 MeV electron fluence are presented to highlight pertinent space weather relationships, and the importance of understanding the complex particle interaction processes involved.

    Key words. Magnetospheric physics (energetic particles; trapped; solar wind – magnetosphere interactions – space plasma physics (spacecraft sheaths, wakes, charging

  16. A solar cycle of spacecraft anomalies due to internal charging

    Directory of Open Access Journals (Sweden)

    G. L. Wrenn

    2002-07-01

    Full Text Available It is important to appreciate how the morphology of internal charging of spacecraft systems, due to penetrating electrons, differs from that of the more common surface charging, due to electrons with lower energy. A specific and recurrent anomaly on a geostationary communication satellite has been tracked for ten years so that solar cycle and seasonal dependencies can be clearly established. Concurrent measurements of sunspot number, solar wind speed and 2-day >2 MeV electron fluence are presented to highlight pertinent space weather relationships, and the importance of understanding the complex particle interaction processes involved.Key words. Magnetospheric physics (energetic particles; trapped; solar wind – magnetosphere interactions – space plasma physics (spacecraft sheaths, wakes, charging

  17. Transient thermal stresses in composite hollow circular cylinder due to partial heat generation

    International Nuclear Information System (INIS)

    Goshima, Takahito; Miyao, Kaju

    1979-01-01

    Clad materials are adopted for the machines and structures used in contact with high temperature, corrosive atmosphere in view of their strength and economy. Large thermal stress sometimes arises in clad cylinders due to uneaven temperature field and the difference in linear thermal expansion. Vessels are often heated uneavenly, and shearing stress occurs, which is not observed in uniform heating. In this study, infinitely long, concentric cylinders of two layers were analyzed, when the internal heat changing in stepped state is generated in cylindrical form. The unsteady thermal stress occurred was determined, using thermo-elastic potential and stress functions, and assuming the thermal properties and elastic modulus of materials as constant regardless of the temperature. Laplace transformation was used, and the basic equations for thermo-elastic displacement were employed as the basis of calculation. The analysis of the temperature distribution and stress is explained. Numerical calculation was carried out on the example of an internal cylinder of SUS 304 stainless steel and an external cylinder of mild steel. The maximum shearing stress occurred in the direction of 40 deg from the heat source, and was affected largely by the position of heat generation. The effect became remarkable as time elapsed. (Kako, I.)

  18. Heat exchanger nozzle stresses due to pipe vibration

    International Nuclear Information System (INIS)

    Wolgemuth, G.A.

    1983-01-01

    A large diameter pipe in a heavy water production plant was excited into a low frequency vibration due to void collapse of the pipe contents at a sharp vertical drop in the pipe run. Fears that this vibration would fatigue the inlet nozzle to the heat exchanger prompted the introduction of a flow of cold water into the pipe to prevent the two-phase flow from developing but at the cost of reduced heat exchanger efficiency. An investigation was carried out to determine the stress levels in the nozzle with the quenching flow off and suggest means of reducing them if excessive. A finite element dynamic simulation of the pipe run was performed to determine the likely mode shapes. This information was used to optimize the placement of velocity probes on the pipe. Field measurements of vibration were taken for several operating conditions. This data was analyzed and the results used to refine the support stiffness used in the finite element simulation. The finite element model was then used to predict the nozzle forces and moments. In turn this data was used to determine the local stresses in the nozzle. The ASME Section III code was used to determine the allowable fully reversing stresses for the unit in question. It was found that the endurance limit of 83 MPa was exceeded in the analysis only when using the most conservative estimates for each uncertainty. It was recommended that if the safety factor was not deemed high enough, the nozzle should be built up with a reinforcing pad no thicker than 12 mm

  19. Stress distributions due to hydrogen concentrations in electrochemically charged and aged austenitic stainless steel

    International Nuclear Information System (INIS)

    Rozenak, P.; Loew, A.

    2008-01-01

    As a result of hydrogen concentration gradients in type austenitic stainless steels, formed during electrochemical charging and followed by hydrogen loss during aging, at room temperature, surface stresses were developed. These stresses were measured by X-ray technique and the crack formation thus induced could be studied using equilibrium stress equations. After various electrochemical charging and aging times, X-ray diffraction patterns obtained from samples indicated that the reflected and broadened diffraction peaks are the result of the formation of a non-uniform but continuous solid solution in the austenitic matrix. Since both hydrogen penetrations during charging and hydrogen release during aging are diffusion controlled processes and huge hydrogen concentration gradients in the thin surface layer, at depths comparable with the depth of X-ray penetration, are observed. The non-uniform hydrogen concentration in the austenitic matrix, results to the non-uniform expansion of the atomic microstructure and latter inevitably leads to the development of internal stresses. The internal stresses development formulae's are very similar to those relating to non-uniform heating of the materials, where thermal stresses appear due to non-uniform expansion or contraction. The relevant well developed theory is applicable in our case of non-uniform hydrogen concentrations in a solid solution of electrochemically charged and aged austenitic matrix. A few cracks were present on the surface after some minutes of electrochemical charging and the severity of cracking increased as hydrogen was lost during subsequent aging. This is consistent with the expectation of high compressive stresses in the bulk of the specimen during charging and high tensile surface stresses (at the level of 1 x 10 11 Pa) during the aging process. These stresses can induce the formation of surface cracks during the aging process after electrochemical charging in the AISI 316 stainless steel

  20. Rotation of principal axes and changes of stress due to mine-induced stresses

    Czech Academy of Sciences Publication Activity Database

    Ptáček, Jiří; Koníček, Petr; Staš, Lubomír; Waclawik, Petr; Kukutsch, Radovan

    2015-01-01

    Roč. 52, č. 10 (2015), s. 1440-1447 ISSN 0008-3674. [International Colloquium on Geomechanics and Geophysics /5./. Karolinka, 25.06.2014-27.06.2014] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : mining * principal stress * stress distribution * modified overcoring Subject RIV: DH - Mining , incl. Coal Mining Impact factor: 1.877, year: 2015 http://www.nrcresearchpress.com/doi/full/10.1139/cgj-2014-0364#.VgqDPpc70mt

  1. Stress analysis in curved composites due to thermal loading

    Science.gov (United States)

    Polk, Jared Cornelius

    Many structures in aircraft, cars, trucks, ships, machines, tools, bridges, and buildings, consist of curved sections. These sections vary from straight line segments that have curvature at either one or both ends, segments with compound curvatures, segments with two mutually perpendicular curvatures or Gaussian curvatures, and segments with a simple curvature. With the advancements made in multi-purpose composites over the past 60 years, composites slowly but steadily have been appearing in these various vehicles, compound structures, and buildings. These composite sections provide added benefits over isotropic, polymeric, and ceramic materials by generally having a higher specific strength, higher specific stiffnesses, longer fatigue life, lower density, possibilities in reduction of life cycle and/or acquisition cost, and greater adaptability to intended function of structure via material composition and geometry. To be able to design and manufacture a safe composite laminate or structure, it is imperative that the stress distributions, their causes, and effects are thoroughly understood in order to successfully accomplish mission objectives and manufacture a safe and reliable composite. The objective of the thesis work is to expand upon the knowledge of simply curved composite structures by exploring and ascertaining all pertinent parameters, phenomenon, and trends in stress variations in curved laminates due to thermal loading. The simply curved composites consist of composites with one radius of curvature throughout the span of the specimen about only one axis. Analytical beam theory, classical lamination theory, and finite element analysis were used to ascertain stress variations in a flat, isotropic beam. An analytical method was developed to ascertain the stress variations in an isotropic, simply curved beam under thermal loading that is under both free-free and fixed-fixed constraint conditions. This is the first such solution to Author's best knowledge

  2. Photoelastic stress analysis in mitred bend under internal pressure

    International Nuclear Information System (INIS)

    Sawa, Yoshiaki

    1987-01-01

    The stress analysis and stress relaxation in mitred bend subjected to internal pressure have been studied by means of the photoelastic stress freezing method. The experimental results show that stress concentration occurs in the wedge tip of the intersectional plane and it is considerably influenced by the bent angle. Then, the stress relaxation was obtained by planing the wedge tip. (author)

  3. Effect of internal stress on the strength of PZT ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Tai, Weon Pil; Yun, Yeo Bum; Kim, Song Hee [Kangwon National Univ., Chunchon (Korea, Republic of)

    1996-01-01

    The aim of this study is to investigate the change of bending strength and fatigue strength in the unpolled and poled Pb(Zr, Ti)O ferroelectrics of tetragonal, morphotropic phase boundary (MPB) and rhombohedral composition in terms of internal stress which is measured by XRD method. Before poling treatment the highest bending strength was found in rhombohedral composition. After poling treatment, the bending strength decreased in all compositions but it decreased most remarkably in tetragonal composition. The most prominent decrease of bending strength after poling treatment in tetragonal was attributed to the occurrence of microcracks due to high anisotropic internal stress around grain boundary which was induced by domain alignment toward electric field direction in the microstructure having tetragonality. The decrease of bending strength after poling in MPB and rhombohedral composition was not due to the occurrence of microcracks but to the increase in tensile internal stress perpendicular to the direction of crack propagation by domain alignment. Fatigue strength was higher before poling treatment than after poling treatment for various compositions. 13 refs., 2 tabs., 5 figs.

  4. Internal stresses in α-plutonium during deformation

    International Nuclear Information System (INIS)

    Merz, M.D.

    1976-01-01

    Internal stresses were measured in fine grained (2 μm) and coarse grained (20 μm) α-plutonium. In the fine grained metal the internal stress sigmasub(i), which was interpreted as the stress driving recovery processes near grain boundaries, was weakly dependent on applied stress, sigmasub(a). The effective stress, sigmasub(e) = sigma sub(a) - sigmasub(i), which is the stress to move dislocations, increased nearly 1:1 with applied stress, especially at high applied stresses. The strain rate obeyed the relation epsilon=K(T)sigmasub(e)sup(n) where K(T) is a temperature dependent term and n approximately = 3. The recovery rate in fine grained α-plutonium during creep was concluded to be very sensitive to internal stress. The internal stress in α-plutonium with 20 μm grain size was much higher than in the finer grain metal. (Auth.)

  5. Plain bearing stresses due to forming and oil film pressure

    Energy Technology Data Exchange (ETDEWEB)

    Burke-Veliz, A; Reed, P A S; Syngellakis, S [University of Southampton, School of Engineering Sciences, Southampton SO17 1BJ (United Kingdom); Wang, D; Wahdy, N; Merritt, D, E-mail: allan.burke@itesm.m [MAHLE Engine Systems UK Ltd, 2 Central park Drive, Rugby CV23 0WE (United Kingdom)

    2009-08-01

    This paper describes a methodology for assessing critical stress ranges arising in automotive plain bearings during engine operations. An industry-produced and run simulation program provides information on oil film pressure and overall bearing deformation during accelerated performance tests. This code performs an elasto-hydrodynamic lubrication analysis accounting for the compliance of the housing and journal. Finite element analyses of a multilayer bearing are performed to assess the conditions responsible for possible fatigue damage over the bearing lining. The residual stresses arising from the forming and fitting process are first assessed. The stress analyses over the engine cycle show the intensity and distribution of cyclic tensile and compressive stresses in the bearing. The location of maximum stress range is found to be consistent with the damage observed in accelerated fatigue tests. Critical zones are identified in the lining for possible fatigue crack initiation and growth studies.

  6. Plain bearing stresses due to forming and oil film pressure

    International Nuclear Information System (INIS)

    Burke-Veliz, A; Reed, P A S; Syngellakis, S; Wang, D; Wahdy, N; Merritt, D

    2009-01-01

    This paper describes a methodology for assessing critical stress ranges arising in automotive plain bearings during engine operations. An industry-produced and run simulation program provides information on oil film pressure and overall bearing deformation during accelerated performance tests. This code performs an elasto-hydrodynamic lubrication analysis accounting for the compliance of the housing and journal. Finite element analyses of a multilayer bearing are performed to assess the conditions responsible for possible fatigue damage over the bearing lining. The residual stresses arising from the forming and fitting process are first assessed. The stress analyses over the engine cycle show the intensity and distribution of cyclic tensile and compressive stresses in the bearing. The location of maximum stress range is found to be consistent with the damage observed in accelerated fatigue tests. Critical zones are identified in the lining for possible fatigue crack initiation and growth studies.

  7. Post-traumatic stress disorder due to childbirth: the aftermath.

    Science.gov (United States)

    Beck, Cheryl Tatano

    2004-01-01

    Childbirth qualifies as an extreme traumatic stressor that can result in post-traumatic stress disorder. The reported prevalence of post-traumatic stress disorder after childbirth ranges from 1.5% to 6%. The aim of this phenomenologic study was to describe the essence of mothers' experiences of post-traumatic stress disorder after childbirth. The qualitative research design used for this study was descriptive phenomenology. The main recruitment approach was via the Internet through the help of Trauma and Birth Stress, a charitable trust in New Zealand. Purposive sampling was used and resulted in 38 mothers participating from the countries of New Zealand, the United States, Australia, and the United Kingdom. The participants were asked to describe their experiences with post-traumatic stress disorder after childbirth. Their stories were analyzed using Colaizzi's method of data analysis. Mothers with post-traumatic stress disorder attributable to childbirth struggle to survive each day while battling terrifying nightmares and flashbacks of the birth, anger, anxiety, depression, and painful isolation from the world of motherhood. This glimpse into the lives of mothers with post-traumatic stress disorder attributable to childbirth provides an impetus to increase research efforts in this neglected area.

  8. Magnetostriction of a sphere: stress development during magnetization and residual stresses due to the remanent field

    Science.gov (United States)

    Reich, Felix A.; Rickert, Wilhelm; Stahn, Oliver; Müller, Wolfgang H.

    2017-03-01

    Based on the principles of rational continuum mechanics and electrodynamics (see Truesdell and Toupin in Handbuch der Physik, Springer, Berlin, 1960 or Kovetz in Electromagnetic theory, Oxford University Press, Oxford, 2000), we present closed-form solutions for the mechanical displacements and stresses of two different magnets. Both magnets are initially of spherical shape. The first (hard) magnet is uniformly magnetized and deforms due to the field induced by the magnetization. In the second problem of a (soft) linear-magnetic sphere, the deformation is caused by an applied external field, giving rise to magnetization. Both problems can be used for modeling parts of general magnetization processes. We will address the similarities between both settings in context with the solutions for the stresses and displacements. In both problems, the volumetric Lorentz force density vanishes. However, a Lorentz surface traction is present. This traction is determined from the magnetic flux density. Since the obtained displacements and stresses are small in magnitude, we may use Hooke's law with a small-strain approximation, resulting in the Lamé- Navier equations of linear elasticity theory. If gravity is neglected and azimuthal symmetry is assumed, these equations can be solved in terms of a series. This has been done by Hiramatsu and Oka (Int J Rock Mech Min Sci Geomech Abstr 3(2):89-90, 1966) before. We make use of their series solution for the displacements and the stresses and expand the Lorentz tractions of the analyzed problems suitably in order to find the expansion coefficients. The resulting algebraic system yields finite numbers of nonvanishing coefficients. Finally, the resulting stresses, displacements, principal strains and the Lorentz tractions are illustrated and discussed.

  9. Neutron depolarization study of internal stresses in amorphous Fe40Ni40B20

    International Nuclear Information System (INIS)

    de Jong, M.; Sietsma, J.; Rekveldt, M.T.; van den Beukel, A.

    1997-01-01

    The magnetic domain structure of amorphous ferromagnets with nonzero magnetostriction is mainly determined by the internal stress state because of the magneto-elastic coupling. The stress and field dependence of the domain structure contains important information on the internal stresses in the material. The three-dimensional neutron depolarization technique has been used to study the stress- and field-dependence of the bulk domain structures in both as-quenched and annealed ribbons of the metallic glass Fe 40 Ni 40 B 20 . A three-layer domain structure model corresponding to compressive and tensile internal stresses is presented to explain the measured data. The influence of surface roughness on the interpretation of neutron depolarization measurements in amorphous ribbons is discussed. Finally, the internal stress relaxation due to the annealing is explained in terms of the viscous behaviour of the glass. copyright 1997 American Institute of Physics

  10. Internal stresses in α-plutonium during deformation

    International Nuclear Information System (INIS)

    Merz, M.D.

    1975-01-01

    Internal stresses were measured in fine-grained (2 μm) and coarse-grained (20 μm) α-plutonium. A stress drop technique (strain transient dip test) was used and the measurements were made for applied creep stresses, sigma/sub a/, from 45 MPa (6250 psi) to 207 MPa (30000 psi) and temperatures from 60 to 113 0 C. The internal stress sigma/sub i/ varied from 17 to 84 MPa and had a weak dependence on applied stress. The effective stress, given by sigma/sub e/ = sigma/sub a/-sigma/sub i/, which is associated with the stress to move dislocations, increased nearly one to one with applied stress, especially at high stresses. The strain rate obeyed the relation epsilon = K(T)sigma/sub e//sup n/ where K(T) is a temperature-dependent term given approximately by Kexp (-104 KJ/mol/RT) and n approximately equal to 3. In fine-grained α-plutonium, the internal stress was interpreted as the stress driving recovery processes near grain boundaries. Measurements of internal stress in α- plutonium with 20-μm grain size indicated a much higher internal stress than for the 2-μm grain size. (5 fig) (auth)

  11. Towards a Stress Free Education: International Perspective

    Science.gov (United States)

    Sedere, Upali M.

    2010-01-01

    Stress is simply the body's response to changes that create taxing demands. When one cannot cope with it, these cause distresses. Stress is not always bad. The manageable stress motivates individuals to achieve what he/she wishes to achieve. When one can cope with stress it is called "eustress" which is good. Education in many countries…

  12. L5 radiculopathy due to sacral stress fracture

    International Nuclear Information System (INIS)

    Aylwin, Anthony; Saifuddin, Asif; Tucker, Stuart

    2003-01-01

    We report the case of a 70-year-old man who presented with a history of left buttock pain with radiation into the left leg in an L5 distribution. MRI of the lumbar spine revealed a left sacral stress fracture with periosteal reaction involving the left L5 nerve root anterior to the sacral ala. With spontaneous healing of the fracture, the patient's symptoms resolved completely. (orig.)

  13. Internal stresses in an austeno-ferritic duplex stainless steel

    International Nuclear Information System (INIS)

    Verhaeghe, B.; Brechet, Y.; Louchet, F.; Massoud, J.P.; Touzeau, D.

    1996-04-01

    Austeno-ferritic duplex steels possess microstructures containing comparable volume fractions of hard and soft phases which are bi-percolated. They are therefore liable to develop large internal stresses during straining. The evolution and the relaxation of these stresses and the occurrence of damage are characterized using Bauschinger tests. Thermally aged and non-aged material behaviour are compared. Plastic flow in the hard phase is shown to be significantly efficient in releasing these internal stresses. (authors). 15 refs., 8 figs

  14. International outbreak of Salmonella Oranienburg due to German chocolate

    Directory of Open Access Journals (Sweden)

    Weise Ekkehard

    2005-02-01

    Full Text Available Abstract Background This report describes a large international chocolate-associated Salmonella outbreak originating from Germany. Methods We conducted epidemiologic investigations including a case-control study, and food safety investigations. Salmonella (S. Oranienburg isolates were subtyped by the use of pulsed-field gel electrophoresis (PFGE. Results From 1 October 2001 through 24 March 2002, an estimated excess of 439 S. Oranienburg notifications was registered in Germany. Simultaneously, an increase in S. Oranienburg infections was noted in other European countries in the Enter-net surveillance network. In a multistate matched case-control study in Germany, daily consumption of chocolate (matched odds ratio [MOR]: 4.8; 95% confidence interval [CI]: 1.3–26.5, having shopped at a large chain of discount grocery stores (MOR: 4.2; CI: 1.2–23.0, and consumption of chocolate purchased there (MOR: 5.0; CI: 1.1–47.0 were associated with illness. Subsequently, two brands from the same company, one exclusively produced for that chain, tested positive for S. Oranienburg. In two other European countries and in Canada chocolate from company A was ascertained that also contained S. Oranienburg. Isolates from humans and from chocolates had indistinguishable PFGE profiles. No source or point of contamination was identified. Epidemiological identification of chocolate as a vehicle of infections required two months, and was facilitated by proxy measures. Conclusions Despite the use of improved production technologies, the chocolate industry continues to carry a small risk of manufacturing Salmonella-containing products. Particularly in diffuse outbreak-settings, clear associations with surrogates of exposure should suffice to trigger public health action. Networks such as Enter-net have become invaluable for facilitating rapid and appropriate management of international outbreaks.

  15. Internal Casting Stresses and Dimensional Stability

    DEFF Research Database (Denmark)

    Andriollo, Tito; Vedel-Smith, Nikolaj Kjelgaard; Thorborg, Jesper

    2017-01-01

    , accelerated stress corrosion, decreased fatigue resistance, and so on. In addition, they can also be responsible for undesirable shape distortions, which may compromise the fulfillment of geometrical tolerance requirements. As a consequence, a good understanding of what residual stresses are, how they form......It is common knowledge that cast iron components may be affected by the presence of residual stresses. This often represents a serious threat, because residual stresses almost invariably cause a significant degradation of the most important material properties, such as reduced fracture toughness...

  16. 38 CFR 4.129 - Mental disorders due to traumatic stress.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Mental disorders due to... SCHEDULE FOR RATING DISABILITIES Disability Ratings Mental Disorders § 4.129 Mental disorders due to traumatic stress. When a mental disorder that develops in service as a result of a highly stressful event is...

  17. Analytical model of cracking due to rebar corrosion expansion in concrete considering the structure internal force

    Science.gov (United States)

    Lin, Xiangyue; Peng, Minli; Lei, Fengming; Tan, Jiangxian; Shi, Huacheng

    2017-12-01

    Based on the assumptions of uniform corrosion and linear elastic expansion, an analytical model of cracking due to rebar corrosion expansion in concrete was established, which is able to consider the structure internal force. And then, by means of the complex variable function theory and series expansion technology established by Muskhelishvili, the corresponding stress component functions of concrete around the reinforcement were obtained. Also, a comparative analysis was conducted between the numerical simulation model and present model in this paper. The results show that the calculation results of both methods were consistent with each other, and the numerical deviation was less than 10%, proving that the analytical model established in this paper is reliable.

  18. Prediction of residual stress distributions due to surface machining and welding and crack growth simulation under residual stress distribution

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Katsuyama, JInya; Onizawa, Kunio; Hashimoto, Tadafumi; Mikami, Yoshiki; Mochizuki, Masahito

    2011-01-01

    Research highlights: → Residual stress distributions due to welding and machining are evaluated by XRD and FEM. → Residual stress due to machining shows higher tensile stress than welding near the surface. → Crack growth analysis is performed using calculated residual stress. → Crack growth result is affected machining rather than welding. → Machining is an important factor for crack growth. - Abstract: In nuclear power plants, stress corrosion cracking (SCC) has been observed near the weld zone of the core shroud and primary loop recirculation (PLR) pipes made of low-carbon austenitic stainless steel Type 316L. The joining process of pipes usually includes surface machining and welding. Both processes induce residual stresses, and residual stresses are thus important factors in the occurrence and propagation of SCC. In this study, the finite element method (FEM) was used to estimate residual stress distributions generated by butt welding and surface machining. The thermoelastic-plastic analysis was performed for the welding simulation, and the thermo-mechanical coupled analysis based on the Johnson-Cook material model was performed for the surface machining simulation. In addition, a crack growth analysis based on the stress intensity factor (SIF) calculation was performed using the calculated residual stress distributions that are generated by welding and surface machining. The surface machining analysis showed that tensile residual stress due to surface machining only exists approximately 0.2 mm from the machined surface, and the surface residual stress increases with cutting speed. The crack growth analysis showed that the crack depth is affected by both surface machining and welding, and the crack length is more affected by surface machining than by welding.

  19. Transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations

    International Nuclear Information System (INIS)

    Sugano, Y.

    1980-01-01

    The transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations on two edges are studied by means of the Airy stress function. The purposes of this paper are to present a method of determing the transient thermal stresses in an orthographic rectangular plate with four edges of distinct thermal boundary condition of the third kind which exactly satisfy the traction-free conditions of shear stress over all boundaries including four corners of the plate, and to consider the effects of the anisotropies of material properties and the convective heat transfer on the upper and lower surfaces on the thermal stress distribution. (orig.)

  20. Social Support and Acculturative Stress among Korean International Students

    Science.gov (United States)

    Ra, Young-An

    2016-01-01

    Previous studies have reported that international students in the US experience unique difficulties and acculturative stress related to cultural differences, language barriers, academic pressure, and interpersonal relationships (Mallinckrodt & Leong, 1992). Berry, Kim, Minde, and Mok (1987) defined this "acculturative stress" as…

  1. Needs and Acculturative Stress of International Students in CACREP Programs

    Science.gov (United States)

    Behl, Malvika; Laux, John M.; Roseman, Christopher P.; Tiamiyu, Mojisola; Spann, Sammy

    2017-01-01

    International students enrolled in programs accredited by the Council for Accreditation of Counseling and Related Educational Programs provided acculturative stress and needs data. Acculturative stress was correlated with academic, social, language, and cultural needs. Furthermore, relationships were found between students' types of needs.…

  2. Coping Strategies for Managing Acculturative Stress among Asian International Students

    Science.gov (United States)

    Ra, Young-An; Trusty, Jerry

    2015-01-01

    This article examines the effects of specific coping strategies on managing acculturative stress and acculturation of Asian international students, based on a sample of 220 Asian international students in the U.S. The data were analyzed with hierarchical multiple regression using Baron and Kenny's (1986) mediation procedure. The results supported…

  3. Internal Stresses in Wires for High Field Magnets

    International Nuclear Information System (INIS)

    Han, K.; Embury, J.D.; Lawson, A.C.; Von Dreele, R.B.; Wood, J.T.; Richardson, J.W. Jr.

    1998-01-01

    The codeformation of Cu-Ag or Cu-Nb composite wires used for high field magnets has a number of important microstructural consequences, including the production of very fine scale structures, the development of very high internal surface area to volume ratios during the drawing and the storage of defects at interphase interfaces. In addition, the fabrication and codeformation of phases which differ in crystal structure, thermal expansion, elastic modulus and lattice parameter lead to the development of short wavelength internal stresses. These internal stresses are measured by neutron diffraction and transmission electron microscopy as a function of the imposed drawing strain. The internal stresses lead to important changes in elastic plastic response which can be related to both magnet design and service life and these aspects will be described in detail

  4. Analysis of Mechanical Stresses Due to Voltage Dips in Fixed-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Veluri, Badrinath; Santos-Martin, David; Jensen, Henrik Myhre

    2011-01-01

    stresses transients that may have a detrimental effect on the fatigue life of drivetrain system due to voltage dips. A rainflow cycle counting method for the stress history during the voltage dip event, analyses mean and amplitudes of the counted cycles, their occurrence moment and time of duration.......Voltage dips due to electrical grid faults generate transients of the generator electromagnetic torque which result in significant high stresses and noticeable vibrations for the wind turbine mechanical system. These events may also have a detrimental effect on the fatigue life of important...

  5. Risk factors for psychological stress among international business travellers.

    Science.gov (United States)

    Striker, J; Luippold, R S; Nagy, L; Liese, B; Bigelow, C; Mundt, K A

    1999-04-01

    This study investigated sources of self reported psychological stress among international business travellers at the World Bank, following up on a previous study showing that travellers submitted more insurance claims for psychological disorders. Hypotheses were that work, personal, family, and health concerns, as well as time zone travel, contribute to travel stress. A travel survey was developed from focus groups and consisted of questions about these potential sources of travel stress. Surveys were sent to a random sample of staff, stratified by number of travel missions, age range, and sex. Canonical correlation analyses estimated the association between key survey items on sources of stress and two measures of travel stress. 498 staff completed the survey. More than a third reported high to very high travel stress. Correlations between predictors and travel stress showed that social and emotional concerns (such as impact of travel on family and sense of isolation) contributed the most to such stress, followed by health concerns, and workload upon return from travel. Surprisingly, time zone travel did not contribute to the self reported stress of these travellers. There were few modifiers of stress, although respondents suggested that a day of rest after travel and reduced workloads would help. The current study confirms clinical impressions about several correlates of travel stress. Similar research with travellers in other organisations could help to determine whether the findings from this study are valid and what measures can be taken to reduce the psychological health risks to travellers.

  6. Risk factors for psychological stress among international business travellers

    Science.gov (United States)

    Striker, J.; Luippold, R. S.; Nagy, L.; Liese, B.; Bigelow, C.; Mundt, K. A.

    1999-01-01

    OBJECTIVES: This study investigated sources of self reported psychological stress among international business travellers at the World Bank, following up on a previous study showing that travellers submitted more insurance claims for psychological disorders. Hypotheses were that work, personal, family, and health concerns, as well as time zone travel, contribute to travel stress. METHODS: A travel survey was developed from focus groups and consisted of questions about these potential sources of travel stress. Surveys were sent to a random sample of staff, stratified by number of travel missions, age range, and sex. Canonical correlation analyses estimated the association between key survey items on sources of stress and two measures of travel stress. RESULTS: 498 staff completed the survey. More than a third reported high to very high travel stress. Correlations between predictors and travel stress showed that social and emotional concerns (such as impact of travel on family and sense of isolation) contributed the most to such stress, followed by health concerns, and workload upon return from travel. Surprisingly, time zone travel did not contribute to the self reported stress of these travellers. There were few modifiers of stress, although respondents suggested that a day of rest after travel and reduced workloads would help. CONCLUSIONS: The current study confirms clinical impressions about several correlates of travel stress. Similar research with travellers in other organisations could help to determine whether the findings from this study are valid and what measures can be taken to reduce the psychological health risks to travellers.   PMID:10450241

  7. Stresses and strains in pavement structures due to the effect of temperatures

    Directory of Open Access Journals (Sweden)

    Svilar Mila

    2016-01-01

    Full Text Available At its absolute amount, stresses due to the effect of temperature in the pavement structures, especially those rigid, are often of the same order of magnitude as those resulting from vehicles' load, but it happens that due to such impact many slabs become cracked before the road is handed over into operation. The temperature stresses which occur in pavement structures include stresses due to bending and buckling, stresses due to friction and hidden stresses. Stresses caused by the influence of temperature in the pavement structure during the day are generally below the strength of the component materials so they do not cause the consequences for structure. However, appearance of residual stresses and their accumulation after a sufficiently long period of time may lead to failure in structure, i.e. thermal fatigue. The paper presents the effects of temperature changes on the pavement structures in the physical and mechanical terms, and the manner in which the temperature is taken into account during the design of pavement structures.

  8. Asymmetric magnetoimpedance in amorphous microwires due to bias current: Effect of torsional stress

    International Nuclear Information System (INIS)

    Buznikov, N.A.; Antonov, A.S.; Granovsky, A.B.

    2014-01-01

    The influence of torsional stress on the asymmetric magnetoimpedance in a glass-coated negative magnetostrictive amorphous microwire due to bias current is studied theoretically. The longitudinal and off-diagonal impedance components are found assuming a simplified spatial distribution of the magnetoelastic anisotropy induced by the torsional stress. The asymmetry in the field dependence of the impedance components is attributed to the combination of the circular magnetic field produced by the bias current and a helical anisotropy induced by the torsional stress. The asymmetry in the magnetoimpedance and the low-field hysteresis are analyzed as a function of the bias current and torsional stress. It is shown that the application of torsional stress significantly changes the value of the bias current required to suppress the hysteresis effect. The results obtained may be useful for applications in magnetic-field and stress sensors. - Highlights: • Effects of torsional stress on magnetoimpedance in amorphous microwire are studied. • Asymmetry in magnetoimpedance is analyzed as a function of bias current and stress. • Torsional stress changes the anisotropy and effects on the microwire impedance. • Field-dependence of impedance is anhysteretic when bias current exceeds threshold value. • Threshold bias current can be tuned by the application of torsional stress

  9. Asymmetric magnetoimpedance in amorphous microwires due to bias current: Effect of torsional stress

    Energy Technology Data Exchange (ETDEWEB)

    Buznikov, N.A., E-mail: n_buznikov@mail.ru [Scientific-Research Institute of Natural Gases and Gas Technologies – GAZPROM VNIIGAZ, Razvilka, Leninsky District, Moscow Region 142717 (Russian Federation); Antonov, A.S. [Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Granovsky, A.B. [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation)

    2014-04-15

    The influence of torsional stress on the asymmetric magnetoimpedance in a glass-coated negative magnetostrictive amorphous microwire due to bias current is studied theoretically. The longitudinal and off-diagonal impedance components are found assuming a simplified spatial distribution of the magnetoelastic anisotropy induced by the torsional stress. The asymmetry in the field dependence of the impedance components is attributed to the combination of the circular magnetic field produced by the bias current and a helical anisotropy induced by the torsional stress. The asymmetry in the magnetoimpedance and the low-field hysteresis are analyzed as a function of the bias current and torsional stress. It is shown that the application of torsional stress significantly changes the value of the bias current required to suppress the hysteresis effect. The results obtained may be useful for applications in magnetic-field and stress sensors. - Highlights: • Effects of torsional stress on magnetoimpedance in amorphous microwire are studied. • Asymmetry in magnetoimpedance is analyzed as a function of bias current and stress. • Torsional stress changes the anisotropy and effects on the microwire impedance. • Field-dependence of impedance is anhysteretic when bias current exceeds threshold value. • Threshold bias current can be tuned by the application of torsional stress.

  10. Average thermal stress in the Al+SiC composite due to its manufacturing process

    International Nuclear Information System (INIS)

    Miranda, Carlos A.J.; Libardi, Rosani M.P.; Marcelino, Sergio; Boari, Zoroastro M.

    2013-01-01

    The numerical analyses framework to obtain the average thermal stress in the Al+SiC Composite due to its manufacturing process is presented along with the obtained results. The mixing of Aluminum and SiC powders is done at elevated temperature and the usage is at room temperature. A thermal stress state arises in the composite due to the different thermal expansion coefficients of the materials. Due to the particles size and randomness in the SiC distribution, some sets of models were analyzed and a statistical procedure used to evaluate the average stress state in the composite. In each model the particles position, form and size are randomly generated considering a volumetric ratio (VR) between 20% and 25%, close to an actual composite. The obtained stress field is represented by a certain number of iso stress curves, each one weighted by the area it represents. Systematically it was investigated the influence of: (a) the material behavior: linear x non-linear; (b) the carbide particles form: circular x quadrilateral; (c) the number of iso stress curves considered in each analysis; and (e) the model size (the number of particles). Each of above analyzed condition produced conclusions to guide the next step. Considering a confidence level of 95%, the average thermal stress value in the studied composite (20% ≤ VR ≤ 25%) is 175 MPa with a standard deviation of 10 MPa. Depending on its usage, this value should be taken into account when evaluating the material strength. (author)

  11. Experimental observation of strong mixing due to internal wave focusing over sloping terrain

    NARCIS (Netherlands)

    Swart, A.; Manders, A.; Harlander, U.; Maas, L.R.M.

    2010-01-01

    This paper reports on experimental observation of internal waves that are focused due to a sloping topography. A remarkable mixing of the density field was observed. This result is of importance for the deep ocean, where internal waves are believed to play a role in mixing. The experiments were

  12. Frustration-induced internal stresses are responsible for quasilocalized modes in structural glasses

    Science.gov (United States)

    Lerner, Edan; Bouchbinder, Eran

    2018-03-01

    It has been recently shown [E. Lerner, G. Düring, and E. Bouchbinder, Phys. Rev. Lett. 117, 035501 (2016), 10.1103/PhysRevLett.117.035501] that the nonphononic vibrational modes of structural glasses at low frequencies ω are quasilocalized and follow a universal density of states D (ω ) ˜ω4 . Here we show that the gapless nature of the observed density of states depends on the existence of internal stresses that generically emerge in glasses due to frustration, thus elucidating a basic element underlying this universal behavior. Similarly to jammed particulate packings, low-frequency modes in structural glasses emerge from a balance between a local elasticity term and an internal stress term in the dynamical matrix, where the difference between them is orders of magnitude smaller than their typical magnitude. By artificially reducing the magnitude of internal stresses in a computer glass former in three dimensions, we show that a gap is formed in the density of states below which no vibrational modes exist, thus demonstrating the crucial importance of internal stresses. Finally, we show that while better annealing the glass upon cooling from the liquid state significantly reduces its internal stresses, the self-organizational processes during cooling render the gapless D (ω ) ˜ω4 density of state unaffected.

  13. Acculturative Stress and Adjustment Experiences of Greek International Students

    Science.gov (United States)

    Poulakis, Mixalis; Dike, Craig A.; Massa, Amber C.

    2017-01-01

    This study investigated eight Greek international college students' experiences of acculturation and acculturative stress at a mid-western university in the United States. Semi-structured interviews were conducted with participants and Consensual Qualitative Research methodology was utilized for data analysis to identify contextual themes and…

  14. Market risk stress testing for internationally active financial institutions

    Directory of Open Access Journals (Sweden)

    Marković Petar

    2011-01-01

    Full Text Available The paper develops a comprehensive framework for market risk stress testing in internationally active financial institutions. We begin by defining the scope and type of the stress test and explaining how to select risk factors and the stress time horizon. We then address challenges related to data gathering, followed by in-depth discussion of techniques for developing realistic shock scenarios. Next the process of shock application to a particular portfolio is described, followed by determination of portfolio profit and loss. We conclude by briefly discussing the issue of assigning probability to stress scenarios. We illustrate the framework by considering the development of a ‘worst case’ scenario using global financial market data from Thomson Reuters Datastream.

  15. Multiaxial Stress-Strain Modeling and Effect of Additional Hardening due to Nonproportional Loading

    International Nuclear Information System (INIS)

    Rashed, G.; Ghajar, R.; Farrahi, G.

    2007-01-01

    Most engineering components are subjected to multiaxial rather than uniaxial cyclic loading, which causes multiaxial fatigue. The pre-requisite to predict the fatigue life of such components is to determine the multiaxial stress strain relationship. In this paper the multiaxial cyclic stress-strain model under proportional loading is derived using the modified power law stress-strain relationship. The equivalent strain amplitude consisted of the normal strain excursion and maximum shear strain amplitude is used in the proportional model to include the additional hardening effect due to nonproportional loading. Therefore a new multiaxial cyclic stress-strain relationship is devised for out of phase nonproportional loading. The model is applied to the nonproportional loading case and the results are compared with the other researchers' experimental data published in the literature, which are in a reasonable agreement with the experimental data. The relationship presented here is convenient for the engineering applications

  16. Nonlinear Heart Rate Variability features for real-life stress detection. Case study: students under stress due to university examination.

    Science.gov (United States)

    Melillo, Paolo; Bracale, Marcello; Pecchia, Leandro

    2011-11-07

    This study investigates the variations of Heart Rate Variability (HRV) due to a real-life stressor and proposes a classifier based on nonlinear features of HRV for automatic stress detection. 42 students volunteered to participate to the study about HRV and stress. For each student, two recordings were performed: one during an on-going university examination, assumed as a real-life stressor, and one after holidays. Nonlinear analysis of HRV was performed by using Poincaré Plot, Approximate Entropy, Correlation dimension, Detrended Fluctuation Analysis, Recurrence Plot. For statistical comparison, we adopted the Wilcoxon Signed Rank test and for development of a classifier we adopted the Linear Discriminant Analysis (LDA). Almost all HRV features measuring heart rate complexity were significantly decreased in the stress session. LDA generated a simple classifier based on the two Poincaré Plot parameters and Approximate Entropy, which enables stress detection with a total classification accuracy, a sensitivity and a specificity rate of 90%, 86%, and 95% respectively. The results of the current study suggest that nonlinear HRV analysis using short term ECG recording could be effective in automatically detecting real-life stress condition, such as a university examination.

  17. Stress analysis on passenger deck due to modification from passenger ship to vehicle-carrying ship

    Science.gov (United States)

    Zubaydi, A.; Sujiatanti, S. H.; Hariyanto, T. R.

    2018-03-01

    Stress is a basic concept in learning about material mechanism. The main focus that needs to be brought to attention in analyzing stress is strength, which is the structural capacity to carry or distribute loads. The structural capacity not only measured by comparing the maximum stress with the material’s yield strength but also with the permissible stress required by the Indonesian Classification Bureau (BKI), which certainly makes it much safer. This final project analyzes stress in passenger deck that experiences modification due to load changes, from passenger load to vehicle one, carrying: 6-wheels truck with maximum weight of 14 tons, a passenger car with maximum weight of 3.5 tons, and a motorcycle with maximum weight of 0.4 tons. The deck structure is modelled using finite element software. The boundary conditions given to the structural model are fix and simple constraint. The load that works on this deck is the deck load which comes from the vehicles on deck with three vehicles’ arrangement plans. After that, software modelling is conducted for analysis purpose. Analysis result shows a variation of maximum stress that occurs i.e. 135 N/mm2, 133 N/mm2, and 152 N/mm2. Those maximum stresses will not affect the structure of passenger deck’s because the maximum stress that occurs indicates smaller value compared to the Indonesian Classification Bureau’s permissible stress (175 N/mm2) as well as the material’s yield strength (235 N/mm2). Thus, the structural strength of passenger deck is shown to be capable of carrying the weight of vehicles in accordance with the three vehicles’ arrangement plans.

  18. Degradation of austenitic stainless steel (SS) light water ractor (LWR) core internals due to neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Appajosula S., E-mail: Appajosula.Rao@nrc.gov

    2014-04-01

    Austenitic stainless steels (SSs) are extensively being used in the fabrication of light water reactor (LWR) core internal components. It is because these steels have relatively high ductility, fracture toughness and moderate strength. However, the LWR internal components exposure to neutron irradiation over an extended period of plant operation degrades the materials mechanical properties such as the fracture toughness. This paper summarizes some of the results of the existing open literature data on irradiation assisted stress corrosion cracking (IASCC) of 316 CW steels that have been published by the United States Nuclear Regulatory Commission (USNRC), industry, academia, and other research agencies.

  19. Residual stress relief due to fatigue in tetragonal lead zirconate titanate ceramics

    International Nuclear Information System (INIS)

    Hall, D. A.; Mori, T.; Comyn, T. P.; Ringgaard, E.; Wright, J. P.

    2013-01-01

    High energy synchrotron XRD was employed to determine the lattice strain ε{111}and diffraction peak intensity ratio R{200}in tetragonal PZT ceramics, both in the virgin poled state and after a bipolar fatigue experiment. It was shown that the occurrence of microstructural damage during fatigue was accompanied by a reduction in the gradient of the ε{111}–cos 2 ψ plot, indicating a reduction in the level of residual stress due to poling. In contrast, the fraction of oriented 90° ferroelectric domains, quantified in terms of R{200}, was not affected significantly by fatigue. The change in residual stress due to fatigue is interpreted in terms of a change in the average elastic stiffness of the polycrystalline matrix due to the presence of inter-granular microcracks

  20. Residual stress relief due to fatigue in tetragonal lead zirconate titanate ceramics

    Science.gov (United States)

    Hall, D. A.; Mori, T.; Comyn, T. P.; Ringgaard, E.; Wright, J. P.

    2013-07-01

    High energy synchrotron XRD was employed to determine the lattice strain ɛ{111} and diffraction peak intensity ratio R{200} in tetragonal PZT ceramics, both in the virgin poled state and after a bipolar fatigue experiment. It was shown that the occurrence of microstructural damage during fatigue was accompanied by a reduction in the gradient of the ɛ{111}-cos2 ψ plot, indicating a reduction in the level of residual stress due to poling. In contrast, the fraction of oriented 90° ferroelectric domains, quantified in terms of R{200}, was not affected significantly by fatigue. The change in residual stress due to fatigue is interpreted in terms of a change in the average elastic stiffness of the polycrystalline matrix due to the presence of inter-granular microcracks.

  1. EGFRvIII escapes down-regulation due to impaired internalization and sorting to lysosomes

    DEFF Research Database (Denmark)

    Grandal, Michael V; Zandi, Roza; Pedersen, Mikkel W

    2007-01-01

    . Moreover, internalized EGFRvIII is recycled rather than delivered to lysosomes. EGFRvIII binds the ubiquitin ligase c-Cbl via Grb2, whereas binding via phosphorylated tyrosine residue 1045 seems to be limited. Despite c-Cbl binding, the receptor fails to become effectively ubiquitinylated. Thus, our...... results suggest that the long lifetime of EGFRvIII is caused by inefficient internalization and impaired sorting to lysosomes due to lack of effective ubiquitinylation....

  2. Differences in response to heat stress due to production level and breed of dairy cows

    Science.gov (United States)

    Gantner, Vesna; Bobic, Tina; Gantner, Ranko; Gregic, Maja; Kuterovac, Kresimir; Novakovic, Jurica; Potocnik, Klemen

    2017-09-01

    The climatic conditions in Croatia are deteriorating which significantly increases the frequency of heat stress. This creates a need for an adequate dairy farming strategy. The impact of heat stress can be reduced in many ways, but the best long-term solution includes the genetic evaluation and selection for heat stress resistance. In order to create the basis for genetic evaluation, this research determined the variation in daily milk yield (DMY) and somatic cell count (SCC) as well as the differences in resistance to heat stress due to production level (high, low) and breed (Holstein, Simmental) of dairy cattle breed in Croatia. For statistical analysis, 1,070,554 test-day records from 70,135 Holsteins reared on 5679 farms and 1,300,683 test-day records from 86,013 Simmentals reared on 8827 farms in Croatia provided by the Croatian Agricultural Agency were used. The results of this research indicate that the high-producing cows are much more susceptible to heat stress than low-producing especially Holsteins. Also, the results of this research indicate that Simmental breed, in terms of daily milk production and somatic cell count, could be more resistant to heat stress than Holstein. The following research should determine whether Simmentals are genetically more appropriate for the challenges that are in store for the future milk production in this region. Furthermore, could an adequate production level be achieved with Simmentals by maintaining the heat resistance?

  3. Numerical Methods for the Analysis of Power Transformer Tank Deformation and Rupture Due to Internal Arcing Faults.

    Science.gov (United States)

    Yan, Chenguang; Hao, Zhiguo; Zhang, Song; Zhang, Baohui; Zheng, Tao

    2015-01-01

    Power transformer rupture and fire resulting from an arcing fault inside the tank usually leads to significant security risks and serious economic loss. In order to reveal the essence of tank deformation or explosion, this paper presents a 3-D numerical computational tool to simulate the structural dynamic behavior due to overpressure inside transformer tank. To illustrate the effectiveness of the proposed method, a 17.3 MJ and a 6.3 MJ arcing fault were simulated on a real full-scale 360MVA/220kV oil-immersed transformer model, respectively. By employing the finite element method, the transformer internal overpressure distribution, wave propagation and von-Mises stress were solved. The numerical results indicate that the increase of pressure and mechanical stress distribution are non-uniform and the stress tends to concentrate on connecting parts of the tank as the fault time evolves. Given this feature, it becomes possible to reduce the risk of transformer tank rupture through limiting the fault energy and enhancing the mechanical strength of the local stress concentrative areas. The theoretical model and numerical simulation method proposed in this paper can be used as a substitute for risky and costly field tests in fault overpressure analysis and tank mitigation design of transformers.

  4. Numerical Methods for the Analysis of Power Transformer Tank Deformation and Rupture Due to Internal Arcing Faults

    Science.gov (United States)

    Yan, Chenguang; Hao, Zhiguo; Zhang, Song; Zhang, Baohui; Zheng, Tao

    2015-01-01

    Power transformer rupture and fire resulting from an arcing fault inside the tank usually leads to significant security risks and serious economic loss. In order to reveal the essence of tank deformation or explosion, this paper presents a 3-D numerical computational tool to simulate the structural dynamic behavior due to overpressure inside transformer tank. To illustrate the effectiveness of the proposed method, a 17.3MJ and a 6.3MJ arcing fault were simulated on a real full-scale 360MVA/220kV oil-immersed transformer model, respectively. By employing the finite element method, the transformer internal overpressure distribution, wave propagation and von-Mises stress were solved. The numerical results indicate that the increase of pressure and mechanical stress distribution are non-uniform and the stress tends to concentrate on connecting parts of the tank as the fault time evolves. Given this feature, it becomes possible to reduce the risk of transformer tank rupture through limiting the fault energy and enhancing the mechanical strength of the local stress concentrative areas. The theoretical model and numerical simulation method proposed in this paper can be used as a substitute for risky and costly field tests in fault overpressure analysis and tank mitigation design of transformers. PMID:26230392

  5. Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix

    Energy Technology Data Exchange (ETDEWEB)

    Tummala, Hareesh [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Capolungo, Laurent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tome, Carlos N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-19

    This report is a preliminary study on δ-hydride precipitate in zirconium alloy performed using 3D discrete dislocation dynamics simulations. The ability of dislocations in modifying the largely anisotropic stress fields developed by the hydride particle in a matrix phase is addressed for a specific dimension of the hydride. The influential role of probable dislocation nucleation at the hydride-matrix interface is reported. Dislocation nucleation around a hydride was found to decrease the shear stress (S13) and also increase the normal stresses inside the hydride. We derive conclusions on the formation of stacks of hydrides in zirconium alloys. The contribution of mechanical fields due to dislocations was found to have a non-negligible effect on such process.

  6. Stress triggering of earthquakes and subsidence in the Louisiana coastal zone due to hydrocarbon production

    Science.gov (United States)

    Mallman, Ellen P.

    This thesis presents contributions towards better understanding of the interaction between earthquakes through elastic stress triggering and the role of hydrocarbon production on subsidence and land loss in southern Louisiana. The first issue addressed in this thesis is that of the role of static stress changes on earthquake triggering. The first study investigated whether observed changes in seismicity rate following the 1992 Landers, California and 1995 Kobe, Japan earthquakes are accurately predicted by elastic Coulomb stress transfer models. The analyses found that for all the tested DeltaCFS models wherever seismicity rate changes could be resolved the rate increased regardless of whether the DeltaCFS theoretically promoted or inhibited failure. The second study the common definition of a stress shadow was extended to independently test the stress shadow hypothesis using a global catalog of seismicity. The analyses indicated that while stress shadows are subtle, they are present in the global catalog. It also explains why "classical" stress shadows, similar to what was observed following the 1906 San Francisco earthquake are rarely observed for individual main shocks. The second issue addressed in this thesis is the role of hydrocarbon production on subsidence and land loss in the Louisiana Coastal Zone. The two studies in this thesis extend previous work by modeling the effect of oil and gas production in the region in two ways. First, multiple producing oil and gas fields and multiple epochs of leveling data are considered to provide constraints on predicted subsidence. Second, the role of compaction of the reservoir bounding shales on the regional subsidence signal is included. The results of the two studies on the role of hydrocarbon production on subsidence in the Louisiana Coastal Zone indicate that regional models of subsidence must include the effects of production-induced subsidence due to both sands and shales, but that this can not account for the

  7. Atmosferic pollution due to sea traffic. An overview on international legislation

    International Nuclear Information System (INIS)

    Landri, G.; Prati, M.V.

    1999-01-01

    Only recently the attention for the injuries to human and environmental health due to vehicular pollutant emission has been enlarged to the sea traffic. Consequently, technologies and local and international actions has been developed to control the phenomenon. In this paper the activities undertaken in the marine field, comparing the two types of traffic with references to the relevant legislations, are shown [it

  8. Internal dosimetric evaluation due to uranium aerosols; Evaluacion dosimetrica interna debido a aerosoles de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Juan, Garcia Aguilar; Gustavo, Delgado Avila [Instituto Nacional de Investigaciones Nucleares, Salazar (Mexico)

    1991-07-01

    The present work has like object to carry out the internal dosimetric evaluation to the occupationally exposed personnel, due to the inhalation of aerosols of natural uranium and enriched in the pilot plant of nuclear fuel production of the National Institute of Nuclear Research.

  9. Surface and Internal Waves due to a Moving Load on a Very Large Floating Structure

    Directory of Open Access Journals (Sweden)

    Taro Kakinuma

    2012-01-01

    Full Text Available Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic thin plate floating on the water surface. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one-layer water with a floating thin plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the velocity of moving point load is equal to the surface- or internal-mode celerity, respectively.

  10. Scattering factor evaluation for internal dose assessment due to 60Co

    International Nuclear Information System (INIS)

    Gautam, Y.P.; Kumar, A.; Sharma, S.; Sharma, A.K.; Dube, B.; Hegde, A.G.

    2008-01-01

    Guidelines for the assessment of internal doses from monitoring suggest default measurement of uncertainties (i.e. lognormal scattering factor, SF) to be used for different types of monitoring data. In this paper, SF values have been evaluated for internal contamination due to 60 Co in two cases using whole body counting data. SF values of 1.04 and 1.03 were obtained for case I and II respectively while SF value of 1.03 was obtained using bioassay data for case I. SF evaluated is in good agreement with the default values given by IDEAS guidelines. (author)

  11. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    Science.gov (United States)

    Bandriyana, B.; Utaja

    2010-06-01

    Thermal stratification introduces thermal shock effect which results in local stress and fatique problems that must be considered in the design of nuclear power plant components. Local stress and fatique calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343° C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  12. Psychometric characteristics of the Eating and Appraisal Due to Emotions and Stress Questionnaire and obesity in Mexican university students.

    Science.gov (United States)

    Lazarevich, Irina; Irigoyen-Camacho, María Esther; Velazquez-Alva, María del Consuelo; Salinas-Ávila, Jaqueline

    2015-06-01

    Emotional eating has been defined as eating in a response to negative emotions and it is associated with weight gain. The English version of Eating Appraisal Due to Emotions and Stress Questionnaire (EADES) was developed to assess how individuals use food in order to cope with stress and emotions. To analyze psychometric characteristics of Spanish version of EADES and to identify whether the constructs of EADES were associated with obesity in university students. The EADES (Spanish version) was administered to 232 Mexican university students from 18 to 29 years old. Body Mass Index (BMI) was calculated. A test-retest evaluation was conducted with 75 participants. Cronbach's alpha of EADES was 0.92; the interclass correlation coefficient was 0.88. Regarding BMI and EADES results, the subscale Emotion and Stress Related Eating was significantly associated with obesity (p = 0.026). Through factor analysis of the instrument, three factors were extracted and items that showed factor loading obesity and the 40-items version of the instrument, a statistically significance association was found for the total score (OR = 0.973, p = 0.020) and for the factor Self-confidence related to Emotional Eating component (OR = 0.940, p = 0.026). A good internal consistency and temporal stability of the Spanish version of the instrument were found; the 40-item EADES version was positively associated with obesity. This instrument could be useful in assessing emotional eating. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  13. Mapping residual and internal stress in materials by neutron diffraction

    International Nuclear Information System (INIS)

    Withers, Ph.J.

    2007-01-01

    Neutron diffraction provides one of the few means of mapping residual stresses deep within the bulk of materials and components. This article reviews the basic scientific methodology by which internal strains and stresses are inferred from recorded diffraction peaks. Both conventional angular scans and time-of-flight measurements are reviewed and compared. Their complementarity with analogous synchrotron X-ray methods is also highlighted. For measurements to be exploited in structural integrity calculations underpinning the safe operation of engineering components, measurement standards have been defined and the major findings are summarised. Examples are used to highlight the unique capabilities of the method showing how it can provide insights ranging from the basic physics of slip mechanisms in hexagonal polycrystalline materials, through the materials optimisation of stress induced transformations in smart nano-materials, to the industrial introduction of novel friction welding processes exploiting stress residual measurements transferred from prototype sub-scale tests to the joining of full-scale aero-engine assemblies. (author)

  14. Relationship between occupational stress and depressive mood among interns and residents in a tertiary hospital, Seoul, Korea.

    Science.gov (United States)

    Kim, Keon; Lee, Sunhwa; Choi, Yoon Hee

    2015-06-01

    Occupational stress can have a harmful effect on the individual both physically and psychologically. In Korea, occupational stress of physician is rarely demonstrated. Although it is well reported that physicians tend to have a high incidence of minor psychiatric disorders, the magnitude of the problem remains unclear. Interns and residents are thought to be under substantial amount of stress, and tend to have psychiatric disorder. In this paper, we aimed to evaluate the relationship between the occupational stress and depression of residents. The participants of this study were surgical and medical residents in a tertiary hospital in Korea. For measurement of occupational stress, we used an occupational stress scale. In addition, to evaluate the prevalence of depression, we used the Beck Depression Inventory. Female doctors showed higher degree of occupational stress than the males. The interns and chief residents showed higher degree of occupational stress than the other residents. Interestingly, in this study, most of the participants experienced a depressive mood. Compared with the general population, job demand and culture of workplace were high. Occupational stress was the only significant predictor of a depressive mood. Hospital residents experience a high degree of occupational stress leading to a depressed mood due to various risk factors. Therefore, it is essential to recognize the occupational stress of residents early, to encourage positive competition and peer and social support, and to help improve the residents' ability to cope with stress.

  15. Grain boundary cavity growth under applied stress and internal pressure

    International Nuclear Information System (INIS)

    Mancuso, J.F.

    1977-08-01

    The growth of grain boundary cavities under applied stress and internal gas pressure was investigated. Methane gas filled cavities were produced by the C + 4H reversible CH4 reaction in the grain boundaries of type 270 nickel by hydrogen charging in an autoclave at 500 0 C with a hydrogen pressure of either 3.4 or 14.5 MPa. Intergranular fracture of nickel was achieved at a charging temperature of 300 0 C and 10.3 MPa hydrogen pressure. Cavities on the grain boundaries were observed in the scanning electron microscope after fracture. Photomicrographs of the cavities were produced in stereo pairs which were analyzed so as to correct for perspective distortion and also to determine the orientational dependence of cavity growth under an applied tensile stress

  16. Initial stresses in two-layer metal domes due to imperfections of their production and assemblage

    Directory of Open Access Journals (Sweden)

    Lebed Evgeniy Vasil’evich

    2015-04-01

    Full Text Available The process of construction of two-layer metal domes is analyzed to illustrate the causes of initial stresses in the bars of their frames. It has been noticed that it is impossible to build such structures with ideal geometric parameters because of imperfections caused by objective reasons. These imperfections cause difficulties in the process of connection of the elements in the joints. The paper demonstrates the necessity of fitting operations during assemblage that involve force fitting and yield initial stresses due to imperfections. The authors propose a special method of computer modeling of enforced elimination of possible imperfections caused by assemblage process and further confirm the method by an analysis of a concrete metal dome.

  17. Assessment of stress due to hot ambience in donkeys from arid tracts in India

    Directory of Open Access Journals (Sweden)

    Kataria N.

    2010-11-01

    Full Text Available To assess the stress due to hot ambience in donkeys from arid tracts in Rajasthan state, India, serum prolactin and cortisol levels were determined by radioimmunoassay. The blood samples to harvest the serum were collected from the same animals during moderate (maximum temperature of 28 C - 29 C and hot (maximum temperature of 45 C- 46 C ambiences. During hot ambience the animals showed significantly (p0.05 higher levels of serum prolactin and cortisol when compared to the moderate ambience. The mean rise in prolactin was 4.42 times whereas cortisol levels were 4.22 times higher. Further a multiple fold rise in serum prolactin clearly suggested that it can also be used as an indicator of stress in donkeys along with the cortisol.

  18. INTERNAL STRUCTURE OF ASTEROIDS HAVING SURFACE SHEDDING DUE TO ROTATIONAL INSTABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Hirabayashi, Masatoshi [Research Associate, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States); Sánchez, Diego Paul [Senior Research Associate, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States); Scheeres, Daniel J., E-mail: masatoshi.hirabayashi@colorado.edu [Richard Seebass Chair, Professor, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States)

    2015-07-20

    Surface shedding of an asteroid is a failure mode where surface materials fly off due to strong centrifugal forces beyond the critical spin period, while the internal structure does not deform significantly. This paper proposes a possible structure of an asteroid interior that leads to surface shedding due to rapid rotation rates. A rubble pile asteroid is modeled as a spheroid composed of a surface shell and a concentric internal core, the entire assembly called the test body. The test body is assumed to be uniformly rotating around a constant rotation axis. We also assume that while the bulk density and the friction angle are constant, the cohesion of the surface shell is different from that of the internal core. First, developing an analytical model based on limit analysis, we provide the upper and lower bounds for the actual surface shedding condition. Second, we use a Soft-sphere Discrete Element Method (SSDEM) to study dynamical deformation of the test body due to a quasi-static spin-up. In this paper we show the consistency of both approaches. Additionally, the SSDEM simulations show that the initial failure always occurs locally and not globally. In addition, as the core becomes larger, the size of lofted components becomes smaller. These results imply that if there is a strong core in a progenitor body, surface shedding is the most likely failure mode.

  19. INTERNAL STRUCTURE OF ASTEROIDS HAVING SURFACE SHEDDING DUE TO ROTATIONAL INSTABILITY

    International Nuclear Information System (INIS)

    Hirabayashi, Masatoshi; Sánchez, Diego Paul; Scheeres, Daniel J.

    2015-01-01

    Surface shedding of an asteroid is a failure mode where surface materials fly off due to strong centrifugal forces beyond the critical spin period, while the internal structure does not deform significantly. This paper proposes a possible structure of an asteroid interior that leads to surface shedding due to rapid rotation rates. A rubble pile asteroid is modeled as a spheroid composed of a surface shell and a concentric internal core, the entire assembly called the test body. The test body is assumed to be uniformly rotating around a constant rotation axis. We also assume that while the bulk density and the friction angle are constant, the cohesion of the surface shell is different from that of the internal core. First, developing an analytical model based on limit analysis, we provide the upper and lower bounds for the actual surface shedding condition. Second, we use a Soft-sphere Discrete Element Method (SSDEM) to study dynamical deformation of the test body due to a quasi-static spin-up. In this paper we show the consistency of both approaches. Additionally, the SSDEM simulations show that the initial failure always occurs locally and not globally. In addition, as the core becomes larger, the size of lofted components becomes smaller. These results imply that if there is a strong core in a progenitor body, surface shedding is the most likely failure mode

  20. Differential relations between youth internalizing/externalizing problems and cortisol responses to performance vs. interpersonal stress.

    Science.gov (United States)

    Laurent, Heidemarie; Vergara-Lopez, Chrystal; Stroud, Laura R

    2016-09-01

    Efforts to define hypothalamic-pituitary-adrenal (HPA) axis profiles conferring risk for psychopathology have yielded inconclusive results, perhaps in part due to limited assessment of the stress response. In particular, research has typically focused on HPA responses to performance tasks, while neglecting the interpersonal stressors that become salient during adolescence. In this study we investigated links between psychosocial adjustment - youth internalizing and externalizing problems, as well as competence - and HPA responses to both performance and interpersonal stressors in a normative sample of children and adolescents. Participants (n = 59) completed a set of performance (public speaking, mental arithmetic, mirror tracing) and/or interpersonal (peer rejection) tasks and gave nine saliva samples, which were assayed for cortisol. Hierarchical linear models of cortisol response trajectories in relation to child behavior checklist (CBCL) scores revealed stressor- and sex-specific associations. Whereas internalizing problems related to earlier peaking, less dynamic cortisol responses to interpersonal stress (across males and females), externalizing problems related to lower, earlier peaking and less dynamic cortisol responses to performance stress for males only, and competence-related to later peaking cortisol responses to interpersonal stress for females only. Implications for understanding contextual stress profiles underlying different forms of psychopathology are discussed.

  1. Finite element simulations of internal stresses generated during the ferroelastic deformation of NiTi bodies

    International Nuclear Information System (INIS)

    Manach, P.Y.; Favier, D.; Rio, G.

    1996-01-01

    The aim of this paper is to analyse the generation of internal stresses during the predeformation of NiTi shape memory alloys in the martensitic state. This allows to determine the initial stress state in which the material will transform during the shape memory effect due to heating consecutively to this prestrain. In that way a three-dimensional finite element model of the deformation of shape memory alloys has been developed, the constitutive law being defined using an elastohysteresis tensor model. The influence of behavioural and geometrical factors are illustrated considering the numerical simulation of different cases of practical importance for industrial applications : the study of the bending behaviour of a NiTi cantilever beam as well as the study of the swelling of a pipe connection under both uniform and non uniform internal displacement fields. (orig.)

  2. Lithosphere stress changes due to groundwater unloading in North China Plain

    Science.gov (United States)

    Pang, Yajin; Zhang, Huai; Shi, Yaolin

    2015-04-01

    During the past 50 years, excessive groundwater pumping has led to the continuous decline of groundwater table in North China Plain, which becomes one of the global hotspots of groundwater depletion. Over most of the rural areas of the plain, the shallow aquifer has experienced a water-table decline of more than 15m, with greater declines up to 50m in most urban centres, such as Beijing, Tangshan, Shijiangzhuang and so forth in 1960-2000. The entire groundwater depletion area covers a total area of approximately 56,273 km2 , more than 40% of the North China Plain. The vast area of enormous groundwater exploitation in North China Plain will definitely unload the lithosphere and create stress perturbations, the problem is if the stresses change large enough to affect tectonic activities. In this essay, we set up a 3 dimensional numerical visco-elastic model to discuss the effect of groundwater over-pumping on the lithosphere deformation and stress state in North China Plain. Based on the records of total groundwater-table decline during 1960-2010 in North China Plain, we estimate the accumulated deformation and lithosphere stress due to unloading of human-induced groundwater depletion. The area in the model ranges from 34° To 42°N, and 112° To 119°E, including the major groundwater depression cones in North China Plain. According to the simulating result, the maximum surface vertical uplift caused by groundwater unloading is 8cm. Meanwhile cumulative horizontal crustal stress changes near the surface goes up to 100kPa, and up to 40kPa at 15km depth where most earthquakes occurred in this area. The tectonic compressive stress rate is about 0.25kPa per year. Therefore, the stress changes due to groundwater pumping is significant compared with the tectonic driven stress changes. As China developed rapidly since 1978, the groundwater table mainly declined after 1978. Taking the earthquake catalog in the vicinity of groundwater depression zone into consideration, we

  3. Internal stress model for pre-primary stage of low-stress creep

    International Nuclear Information System (INIS)

    Kloc, L

    2010-01-01

    Initial transient stage in low-stress creep experiments was observed in all such experiments. Recently, evidences were presented that this stage cannot be considered as a normal creep primary stage, though the shape of the creep curve is similar. The strain reached during this so called pre-primary stage is fully recoverable upon unloading; the internal stresses must play important role in the effect. Model of standard linear anelastic solid was modified by introduction of creeping body instead of viscous dashpot. Both power law and hyperbolic sine creep law were used to fit observed creep curves of model and structural materials. Mainly the model using hyeprbolic sine creep law provides good fit to individual creep curves and sets of creep curves at different stresses.

  4. Emotion regulation's relationships with depression, anxiety and stress due to imagined smartphone and social media loss.

    Science.gov (United States)

    Elhai, Jon D; Hall, Brian J; Erwin, Meredith Claycomb

    2018-03-01

    A sample of 359 students participated in a web survey, administered the Emotion Regulation Questionnaire, and Depression Anxiety Stress Scale-21 (DASS-21) as a pre-test. We subsequently randomly assigned subjects to either 1) a smart phone loss group or 2) social media accounts loss group. We asked them to imagine losing two days' access to the technology in their respective group, and rate associated symptoms using the DASS-21. Compared to subjects in the smartphone loss group, social media loss subjects evidenced stronger relations between suppressive emotion regulation with depression, anxiety and stress from imagined loss. Controlling for age and gender, social media loss subjects' increased use of suppression, and decreased use of cognitive reappraisal in emotion regulation, were related to depression, stress and (for suppression only) anxiety due to imagined lost social media. Emotion regulation was not related to psychopathology for subjects in the smartphone loss scenario. Results suggest that emotion dysregulation may be associated with psychopathology from social media loss. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Prenatal Stress due to a Natural Disaster Predicts Adiposity in Childhood: The Iowa Flood Study

    Directory of Open Access Journals (Sweden)

    Kelsey N. Dancause

    2015-01-01

    Full Text Available Prenatal stress can affect lifelong physical growth, including increased obesity risk. However, human studies remain limited. Natural disasters provide models of independent stressors unrelated to confounding maternal characteristics. We assessed degree of objective hardship and subjective distress in women pregnant during severe flooding. At ages 2.5 and 4 years we assessed body mass index (BMI, subscapular plus triceps skinfolds (SS + TR, an index of total adiposity, and SS : TR ratio (an index of central adiposity in their children (n=106. Hierarchical regressions controlled first for several potential confounds. Controlling for these, flood exposure during early gestation predicted greater BMI increase from age 2.5 to 4, as well as total adiposity at 2.5. Greater maternal hardship and distress due to the floods, as well as other nonflood life events during pregnancy, independently predicted greater increase in total adiposity between 2.5 and 4 years. These results support the hypothesis that prenatal stress increases adiposity beginning in childhood and suggest that early gestation is a sensitive period. Results further highlight the additive effects of maternal objective and subjective stress, life events, and depression, emphasizing the importance of continued studies on multiple, detailed measures of maternal mental health and experience in pregnancy and child growth.

  6. Quantifying Cyclic Thermal Stresses Due to Solar Exposure in Rock Fragments in Gale Crater, Mars

    Science.gov (United States)

    Hallet, B.; Mackenzie-Helnwein, P.; Sletten, R. S.

    2017-12-01

    Curiosity and earlier rovers on Mars have revealed in detail rocky landscapes with decaying outcrops, rubble, stone-littered regolith, and bedrock exposures that reflect the weathering processes operating on rock exposed to Mars' cold and hyperarid environment. Evidence from diverse sources points to the importance of thermal stresses driven by cyclic solar exposure in contributing to the mechanical weathering of exposed rock and generation of regolith in various settings on Earth [1,2,3], and even more so on extraterrestrial bodies where large, rapid cyclic temperature variations are frequent (e.g. Mars [4], as well as comets [5], asteroids [6] and other airless bodies [7]). To study these thermal stresses, we use a 3d finite element (FE) model constrained by ground-based surface temperature measurements from Curiosity's Environmental Monitoring Station (REMS). The numerical model couples radiation and conduction with elastic response to determine the temperature and stress fields in individual rocks on the surface of Mars based on rock size and thermo-mechanical properties. We provide specific quantitative results for boulder-size basalt rocks resting on the ground using a realistic thermal forcing that closely matches the REMS temperature observations, and related thermal inertia data. Moreover, we introduce analytical studies showing that these numerical results can readily be generalized. They are quite universal, informing us about thermal stresses due to cyclic solar exposure in general, for rock fragments of different sizes, lithologies, and fracture- thermal- and mechanical-properties. Using Earth-analogue studies to gain insight, we also consider how the shapes, fractures, and surface details of rock fragments imaged by Curiosity likely reflect the importance of rock breakdown due to thermal stresses relative to wind-driven rock erosion and other surface processes on Mars. References:[1] McFadden L et al. (2005) Geol. Soc.Am. Bull. 117(1-2): 161-173 [2

  7. Internal friction due to domain-wall motion in martensitically transformed A15 compounds

    International Nuclear Information System (INIS)

    Snead, C.L. Jr.; Welch, D.O.

    1985-01-01

    A lattice instability in A15 materials in some cases leads to a cubic-to-tetragonal martensitic transformation at low temperatures. The transformed material orients in lamellae with c axes alternately aligned along the directions producing domain walls between the lamellae. An internal-friction (delta) feature below T/sub m/ is attributed to stress-induced domain-wall motion. The magnitude of the friction increases as temperature is lowered below T/sub m/ as (1-c/a) increases, and behaves as (1-c/a) 2 from T/sub m/ down to the superconducting critical temperature where the increasing tetragonality is inhibited. The effect of strain in the lattice is to decrease the domain-wall internal friction, but not affect T/sub m/. Neutron-induced disorder and the addition of some third-elements in alloying decrease both delta and T/sub m/, with some elements reducing only the former. Less than 1 at. % H is seen to completely suppress both delta and T/sub m. Martensitically transformed V 2 Zr demonstrates low-temperature internal-friction and modulus behavior consists with easy β/m wall motion relative to the easy m/m motion of the A15's. For the V 2 Zr, a peak in delta is observed, qualitatively in agreement with expected β/m wall motion

  8. Pipeline's natural frequency response due to internal pressure effect

    Energy Technology Data Exchange (ETDEWEB)

    Massa, Andre L.L.; Guevara Junior, Nestor O. [Suporte - Consultoria e Projetos Ltda., Rio de Janeiro, RJ (Brazil); Galgoul, Nelson S. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Fernandes, Antonio C.; Coelho, Fabio M. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Coordenacao de Programas de Pos-graduacao de Engenharia

    2009-12-19

    A few years ago, a discussion about how internal pressure is treated in submarine pipelines has taken place. Galgoul et al (2004) have pointed out the conservatism of the latest recommendations for pipeline free-span evaluations associated to the way the axial force is considered in the determination of the pipeline natural frequency. Fyrileiv and Collberg (2005) have also discussed this point in defense of the effective axial force concept and its use in the natural frequency determination. In order to contribute to this aspect, an experimental test has been performed with a fully embedded pipeline which was pressurized. The main object consists in showing that the pipe is under tension (and not under compression) and, as a consequence, it is the authors' intention to prove that the natural frequency increases instead of reducing when the internal pressure is incremented. In addition to the test, a finite element model has been presented where this internal pressure effect is taken into account as it actually is (and not as an axial force) in order to show the real behavior of the wall stresses. Static analyses, as well as modal and transient analysis have been performed in order to compare theoretical results with the experimental test conducted. (author)

  9. Mechanistic modeling of the loss of protein sieving due to internal and external fouling of microfilters.

    Science.gov (United States)

    Bolton, Glen R; Apostolidis, Alex J

    2017-09-01

    Fed-batch and perfusion cell culture processes used to produce therapeutic proteins can use microfilters for product harvest. In this study, new explicit mathematical models of sieving loss due to internal membrane fouling, external membrane fouling, or a combination of the two were generated. The models accounted for membrane and cake structures and hindered solute transport. Internal membrane fouling was assumed to occur due to the accumulation of foulant on either membrane pore walls (pore-retention model) or membrane fibers (fiber-retention model). External cake fouling was assumed to occur either by the growth of a single incompressible cake layer (cake-growth) or by the accumulation of a number of independent cake layers (cake-series). The pore-retention model was combined with either the cake-series or cake-growth models to obtain models that describe internal and external fouling occurring either simultaneously or sequentially. The models were tested using well-documented sieving decline data available in the literature. The sequential pore-retention followed by cake-growth model provided a good fit of sieving decline data during beer microfiltration. The cake-series and cake-growth models provided good fits of sieving decline data during the microfiltration of a perfusion cell culture. The new models provide insights into the mechanisms of fouling that result in the loss of product sieving. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1323-1333, 2017. © 2017 American Institute of Chemical Engineers.

  10. Effect of combined loading due to bending and internal pressure on pipe flaw evaluation criteria

    International Nuclear Information System (INIS)

    Miura, Naoki; Sakai, Shinsuke

    2006-01-01

    Considering a rational maintenance rule of Light Water Reactor piping, reliable flaw evaluation criteria are essential to determine how a detected flaw is detrimental to continuous plant operation. Ductile fracture is one of the dominant failure modes to be considered for carbon steel piping, and can be analyzed by the elastic-plastic fracture mechanics. Some analytical efforts have been provided as flaw evaluation criteria using load correction factors such like the Z-factors in the JSME codes on fitness-for-service for nuclear power plants or the ASME boiler and pressure vessel code section XI. The present correction factors were conventionally determined taken conservatism and simplicity into account, however, the effect of internal pressure which would be an important factor under an actual plant condition was not adequately considered. Recently, a J-estimation scheme, 'LBB. ENGC' for ductile fracture analysis of circumferentially through-wall-cracked pipes subjected combined loading was newly developed to have a better prediction with more realistic manner. This method is explicitly incorporated the contribution of both bending and tension due to internal pressure by means of the scheme compatible with an arbitrary combined loading history. In this paper, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. A correction factor based on the new J-estimation scheme was compared with the present correction factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of internal pressure. (author)

  11. Response of ENSO amplitude to global warming in CESM large ensemble: uncertainty due to internal variability

    Science.gov (United States)

    Zheng, Xiao-Tong; Hui, Chang; Yeh, Sang-Wook

    2018-06-01

    El Niño-Southern Oscillation (ENSO) is the dominant mode of variability in the coupled ocean-atmospheric system. Future projections of ENSO change under global warming are highly uncertain among models. In this study, the effect of internal variability on ENSO amplitude change in future climate projections is investigated based on a 40-member ensemble from the Community Earth System Model Large Ensemble (CESM-LE) project. A large uncertainty is identified among ensemble members due to internal variability. The inter-member diversity is associated with a zonal dipole pattern of sea surface temperature (SST) change in the mean along the equator, which is similar to the second empirical orthogonal function (EOF) mode of tropical Pacific decadal variability (TPDV) in the unforced control simulation. The uncertainty in CESM-LE is comparable in magnitude to that among models of the Coupled Model Intercomparison Project phase 5 (CMIP5), suggesting the contribution of internal variability to the intermodel uncertainty in ENSO amplitude change. However, the causations between changes in ENSO amplitude and the mean state are distinct between CESM-LE and CMIP5 ensemble. The CESM-LE results indicate that a large ensemble of 15 members is needed to separate the relative contributions to ENSO amplitude change over the twenty-first century between forced response and internal variability.

  12. Association between Independent Reports of Maternal Parenting Stress and Children's Internalizing Symptomatology

    Science.gov (United States)

    Rodriguez, Christina M.

    2011-01-01

    Although considerable research has investigated parenting stress and children's externalizing behavior problems, comparatively less has considered parenting stress in relation to children's internalizing difficulties. Even less research on parenting stress has incorporated children's report of their internalizing symptoms or the potential…

  13. The effect of internal and external stress on two-way shape-memory behaviour in Co49Ni21.6Ga29.4 single crystals

    International Nuclear Information System (INIS)

    Liu, G D; Dai, X F; Luo, H Z; Liu, H Y; Meng, F B; Li, Y; Yu, X; Chen, J L; Wu, G H

    2011-01-01

    The effect of the internal stress on the two-way shape memory in Co 49 Ni 21.6 Ga 29.4 single crystals has been investigated. We found that the internal stress generated natively by the solidifying process works as a tensile force along the growth direction. Applying different compressive pre-stresses along the [0 0 1] direction, the shape-memory strain can be continuously changed from +1.0% to -2.3%. In the [1 1 0] direction, the strain monotonically increases from -2.0% to -4.0% due to a strong detwinning produced by the consistent effect of the external and internal stresses.

  14. Internal dose assessment due to large area contamination: Main lessons drawn from the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Andrasi, A [KFKI Atomic Energy Research Inst., Budapest (Hungary)

    1997-03-01

    The reactor accident at Chernobyl in 1986 beside its serious and tragic consequences provided also an excellent opportunity to check, test and validate all kind of environmental models and calculation tools which were available in the emergency preparedness systems of different countries. Assessment of internal and external doses due to the accident has been carried out for the population all over Europe using different methods. Dose predictions based on environmental model calculation considering various pathways have been compared with those obtained by more direct monitoring methods. One study from Hungary and one from the TAEA is presented shortly. (orig./DG)

  15. Internal dose assessment due to large area contamination: Main lessons drawn from the Chernobyl accident

    International Nuclear Information System (INIS)

    Andrasi, A.

    1997-01-01

    The reactor accident at Chernobyl in 1986 beside its serious and tragic consequences provided also an excellent opportunity to check, test and validate all kind of environmental models and calculation tools which were available in the emergency preparedness systems of different countries. Assessment of internal and external doses due to the accident has been carried out for the population all over Europe using different methods. Dose predictions based on environmental model calculation considering various pathways have been compared with those obtained by more direct monitoring methods. One study from Hungary and one from the TAEA is presented shortly. (orig./DG)

  16. Adolescent internalizing symptoms and negative life events: the sensitizing effects of earlier life stress and cortisol.

    Science.gov (United States)

    Ruttle, Paula L; Armstrong, Jeffrey M; Klein, Marjorie H; Essex, Marilyn J

    2014-11-01

    Although adolescence is marked by increased negative life events and internalizing problems, few studies investigate this association as an ongoing longitudinal process. Moreover, while there are considerable individual differences in the degree to which these phenomena are linked, little is known about the origins of these differences. The present study examines early life stress (ELS) exposure and early-adolescent longitudinal afternoon cortisol level as predictors of the covariation between internalizing symptoms and negative life events across high school. ELS was assessed by maternal report during infancy, and the measure of cortisol was derived from assessments at ages 11, 13, and 15 years. Life events and internalizing symptoms were assessed at ages 15, 17, and 18 years. A two-level hierarchical linear model revealed that ELS and cortisol were independent predictors of the covariation of internalizing symptoms and negative life events. Compared to those with lower levels of ELS, ELS-exposed adolescents displayed tighter covariation between internalizing symptoms and negative life events. Adolescents with lower longitudinal afternoon cortisol displayed tighter covariation between negative life events and internalizing symptoms, while those with higher cortisol demonstrated weaker covariation, partially due to increased levels of internalizing symptoms when faced with fewer negative life events.

  17. Analysis of internal stress and anelasticity in the shock-compressed state from unloading wave data

    International Nuclear Information System (INIS)

    Johnson, J.N.; Lomdahl, P.S.; Wills, J.M.

    1991-01-01

    This paper reports on time resolved shock-wave measurements have often been used to infer microstructural behavior in crystalline solids. The authors apply this approach to an interpretation of the release-wave response of an aluminum alloy (6061-T6) as it is dynamically unloaded from a shock-compressed state of 20.7 GPa. The anelastic behavior in the initial portion of the unloading wave is attributed to the accumulation of internal stresses created by the shock process. Specific internal-stress models which are investigated are the double pile-up, the single pile-up, and single dislocation loops between pinning points. It is found that the essential characteristics of double and single pile-ups can be represented by a single dislocation between two pinned dislocations of like sing. Calculations of anelastic wave speeds at constant unloading strain rate are then compared with experimental data. The results suggest that the residual internal stress is due to pinned loops of density 10 15 M - 2 , and the viscous drag coefficient in the shock-compressed state is on the order of 10 - 7 MPa s (approximately two orders of magnitude greater than expected under ambient conditions)

  18. The Relationships among Perfectionism, Acculturation, and Stress in Asian International Students

    Science.gov (United States)

    Nilsson, Johanna E.; Butler, Jenay; Shouse, Sarah; Joshi, Chetan

    2008-01-01

    This study examined relationships among perfectionism, acculturation, and stress in 76 Asian international students. Results showed that perfectionism and acculturation predicted stress, together accounting for 50% of the variance in stress. Furthermore, acculturation explained students' experience of stress above and beyond perfectionism, and 1…

  19. Event terms in the response spectra prediction equation and their deviation due to stress drop variations

    Science.gov (United States)

    Kawase, H.; Nakano, K.

    2015-12-01

    We investigated the characteristics of strong ground motions separated from acceleration Fourier spectra and acceleration response spectra of 5% damping calculated from weak and moderate ground motions observed by K-NET, KiK-net, and the JMA Shindokei Network in Japan using the generalized spectral inversion method. The separation method used the outcrop motions at YMGH01 as reference where we extracted site responses due to shallow weathered layers. We include events with JMA magnitude equal to or larger than 4.5 observed from 1996 to 2011. We find that our frequency-dependent Q values are comparable to those of previous studies. From the corner frequencies of Fourier source spectra, we calculate Brune's stress parameters and found a clear magnitude dependence, in which smaller events tend to spread over a wider range while maintaining the same maximum value. We confirm that this is exactly the case for several mainshock-aftershock sequences. The average stress parameters for crustal earthquakes are much smaller than those of subduction zone, which can be explained by their depth dependence. We then compared the strong motion characteristics based on the acceleration response spectra and found that the separated characteristics of strong ground motions are different, especially in the lower frequency range less than 1Hz. These differences comes from the difference between Fourier spectra and response spectra found in the observed data; that is, predominant components in high frequency range of Fourier spectra contribute to increase the response in lower frequency range with small Fourier amplitude because strong high frequency component acts as an impulse to a Single-Degree-of-Freedom system. After the separation of the source terms for 5% damping response spectra we can obtain regression coefficients with respect to the magnitude, which lead to a new GMPE as shown in Fig.1 on the left. Although stress drops for inland earthquakes are 1/7 of the subduction

  20. Influence of anisotropy effect and internal stresses upon the superconductive critical temperature of plastically deformed tin

    International Nuclear Information System (INIS)

    Wagner, D.; Stangler, F.

    1976-01-01

    The influence of plastic deformation on the superconductive critical temperature of tin single crystals has been investigated experimentally. It was shown by measurements that the lattice defects produced by plastic deformation lead to an anisotropy effect (according to the theory of Markowitz and Kadanoff), as do impurities in alloyed material. The decrease in T/sub c/ due to this effect can be measured, however, only with samples of certain special orientations. Samples with other orientations show an increase in T/sub c/, which can be explained by the assumption of internal stresses from dislocation pileups. A model is discussed which accounts for the measured rise in T/sub c/

  1. Residual stresses due to weld repairs, cladding and electron beam welds and effect of residual stresses on fracture behavior. Annual report, September 1, 1977--November 30, 1978

    International Nuclear Information System (INIS)

    Rybicki, E.F.

    1978-11-01

    The study is divided into three tasks. Task I is concerned with predicting and understanding the effects of residual stresses due to weld repairs of pressure vessels. Task II examines residual stresses due to an electron beam weld. Task III addresses the problem of residual stresses produced by weld cladding at a nozzle vessel intersection. The objective of Task I is to develop a computational model for predicting residual stress states due to a weld repair of pressure vessel and thereby gain an understanding of the mechanisms involved in the creation of the residual stresses. Experimental data from the Heavy Section Steel Technology (HSST) program at Oak Ridge National Laboratories (ORNL) is used to validate the computational model. In Task II, the residual stress model is applied to the case of an electron beam weld of a compact tension freacture specimen. The results in the form of residual stresses near the weld are then used to explain unexpected fracture behavior which is observed in the testing of the specimen. For Task III, the residual stress model is applied to the cladding process used in nozzle regions of nuclear pressure vessels. The residual stresses obtained from this analysis are evaluated to determine their effect on the phenomena of under-clad cracking

  2. Effect of combined loading due to bending and internal pressure on pipe flaw evaluation criteria

    International Nuclear Information System (INIS)

    Miura, Naoki; Sakai, Shinsuke

    2008-01-01

    Considering a rule for the rationalization of maintenance of Light Water Reactor piping, reliable flaw evaluation criteria are essential for determining how a detected flaw will be detrimental to continuous plant operation. Ductile fracture is one of the dominant failure modes that must be considered for carbon steel piping and can be analyzed by elastic-plastic fracture mechanics. Some analytical efforts have provided various flaw evaluation criteria using load correction factors, such as the Z-factors in the JSME codes on fitness-for-service for nuclear power plants and the section XI of the ASME boiler and pressure vessel code. The present Z-factors were conventionally determined, taking conservativity and simplicity into account; however, the effect of internal pressure, which is an important factor under actual plant conditions, was not adequately considered. Recently, a J-estimation scheme, LBB.ENGC for the ductile fracture analysis of circumferentially through-wall-cracked pipes subjected to combined loading was developed for more accurate prediction under more realistic conditions. This method explicitly incorporates the contributions of both bending and tension due to internal pressure by means of a scheme that is compatible with an arbitrary combined-loading history. In this study, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. The Z-factor obtained in this study was compared with the presently used Z-factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of the internal pressure. (author)

  3. Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

    Science.gov (United States)

    Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

    2016-01-01

    The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to

  4. Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming.

    Science.gov (United States)

    Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

    2016-02-26

    The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to

  5. Internal stress distribution for generating closure domains in laser-irradiated Fe–3%Si(110) steels

    International Nuclear Information System (INIS)

    Iwata, Keiji; Imafuku, Muneyuki; Orihara, Hideto; Sakai, Yusuke; Ohya, Shin-Ichi; Suzuki, Tamaki; Shobu, Takahisa; Akita, Koichi; Ishiyama, Kazushi

    2015-01-01

    Internal stress distribution for generating closure domains occurring in laser-irradiated Fe–3%Si(110) steels was investigated using high-energy X-ray analysis and domain theory based on the variational principle. The measured triaxial stresses inside the specimen were compressive and the stress in the rolling direction became more dominant than stresses in the other directions. The calculations based on the variational principle of magnetic energy for closure domains showed that the measured triaxial stresses made the closure domains more stable than the basic domain without closure domains. The experimental and calculation results reveal that the laser-introduced internal stresses result in the occurrence of the closure domains

  6. False indications of 95Zr-95Nb internal contamination due to contaminated sacred thread

    International Nuclear Information System (INIS)

    Garg, S.P.; Singh, I.S.; Sharma, R.C.

    2000-01-01

    Whole body monitoring of a worker showed an apparent internal contamination with a considerable amount of 95 Zr- 95 Nb. Inhalation exposure was suspected to have taken place about a week earlier when he had last worked in the radioactive area. Unexpected fast clearance indicated by the third periodical weekly follow up monitoring was considered to be an abnormal behaviour. Investigations revealed an external contamination on a sacred thread, which the worker was putting on across his thorax and not removing it at the time of bath due to religious considerations. These studies have underscored that short term follow up measurements data should be critically scrutinized and a caution should be exercised in the interpretation such data particularly in case of such relatively short lived radionuclides. (author)

  7. Epistaxis and pituitary apoplexy due to ruptured internal carotid artery aneurysm embedded within pituitary adenoma.

    Science.gov (United States)

    Peng, Zesheng; Tian, Daofeng; Wang, Hongliu; Kong, Derek Kai; Zhang, Shenqi; Liu, Baohui; Deng, Gang; Xu, Zhou; Wu, Liquan; Ji, Baowei; Wang, Long; Cai, Qiang; Li, Mingchang; Wang, Junmin; Zhang, Aimin; Chen, Qianxue

    2015-01-01

    Epistaxis due to ruptured internal carotid artery (ICA) aneurysm embedded within a pituitary adenoma (PA) has seldom been reported in the literature. Here we want to elaborate the incidence, mechanisms, clinical manifestations, and treatment strategy for this condition. The first survived case of a patient with epistaxis and pituitary apoplexy due to ruptured aneurysm embedded within PA was reported and the literature was reviewed. A 53-year-old male patient presented to our institution with sudden onset epistaxis and progressive vision loss. Neurological examination revealed bilateral ptosis and dilated unresponsive pupils. A CT scan showed a large mass in the pituitary fossa with bony erosion. MRI revealed a large pituitary tumor and abnormal signal intensity in the tumor. No aneurysm was noted during the pre-operative MR angiography. Abundant arterial bleeding suddenly occurred during urgent transsphenoidal surgery. Digital subtraction angiography confirmed the presence of a 14 mm unexpected saccular aneurysm of right ICA in the cavernous sinus with the dome protruding into the sella turcica. Balloon test occlusion of the right ICA was undertaken and permanent occlusion was performed. The patient recovered well and received bromocriptine and thyroid hormone replacement therapy during the follow-up period. At 14-month followup, the patient had no neurological deficits, no features of ischaemia relating to the right ICA therapeutic occlusion. Our case indicated that epistaxis and pituitary apoplexy could be due to the rupture of an ICA aneurysm embedded in a PA. Clinical suspicion should remain high when evaluating any case of epistaxis and pituitary apoplexy. Optimal treatment should take into consideration individual features of the tumor, aneurysm, and patient. Making the correct diagnosis as well as identifying an appropriate management strategy is critical in the care of such patients.

  8. Transient thermal stresses in a transversely isotropic finite hollow circular cylinder due to arbitrary surface heat generations

    International Nuclear Information System (INIS)

    Sugano, Yoshihiro; Nakanishi, Takanori.

    1980-01-01

    The materials macroscopically regarded as anisotropic materials such as fiber-reinforced composite materials have become to be used for the structural elements at elevated temperature, and the studies on the problem of thermal stress in anisotropic bodies are carried out actively. The unsteady thermal stress in anisotropic finite circular cylinders has not been analyzed so far. In this study, the problem of unsteady thermal stress in an anisotropic finite circular cylinder having arbitrary surface heat generation in axial direction on the internal and external surfaces, and emitting heat from both ends and the internal and external surfaces, was analyzed. For the analysis of temperature distribution, generalized finite Fourier transformation and finite Hankel transformation were used, and thermal stress and thermal displacement were analyzed by the use of the stress function of Singh. By adopting the function used for the transformation nucleus in generalized finite Fourier transformation as the stress function, the analysis was made without separating symmetric and opposite symmetric problems. Numerical calculation was carried out on the basis of the analytical results, and the effects of the anisotropy in thermal conductivity, Young's modulus and linear expansion on unsteady temperature distribution, thermal stress and thermal displacement were quantitatively examined. (Kako, I.)

  9. Interstitial relaxations due to hydrostatic stress in niobium--oxygen alloys

    International Nuclear Information System (INIS)

    Tewari, S.N.

    1974-01-01

    Experimental investigations of the anelastic relaxation induced by hydrostatic stress in the range from ambient to 81 ksi were made for niobium--oxygen alloys. The anelastic responses, both for the pressurization and the pressure release experiments, were followed by measuring the relative length change between the oxygenated niobium sample and a pure niobium frame with a precision of about 2 A. The relaxation spectrum observed was shown to be made up of three distinct relaxations with unique relaxation times and strengths. The pressure dependence of the relaxation times gave the apparent activation volume for these relaxations of the order of 4 cm 3 /mole. The relaxations were observed to have relaxation strengths of the order of 10 -4 which were found to be independent of pressure up to 81 ksi. The relaxation times for these relaxations were found to occur in the same general temperature range as those for the Snoek relaxations of oxygen clusters in niobium. The temperature dependence of the relaxation times, however, gave activation energies of about 11 to 15 kcal/mole, as compared with roughly 27 to 29 kcal/mole for the Snoek relaxation of oxygen clusters in niobium. Several possible models for these relaxations were developed, however, none could predict the observed temperature dependence. The best interpretation of the data is that due to some anomalous competing relaxation the actual temperature dependence of these relaxations could not be observed. A completely self-consistent analysis is found which is based upon this assumption. (U.S.)

  10. Relaxation of Si-SiO2 interfacial stress in bipolar screen oxides due to ionizing radiation

    International Nuclear Information System (INIS)

    Witczak, S.C.; Galloway, K.F.; Schrimpf, R.D.; Suehle, J.S.

    1995-01-01

    Current gain degradation due to ionizing radiation in complementary single-crystalline emitter bipolar transistors was found to grow progressively worse upon subjecting the transistors to repeated cycles of radiation exposure and high-temperature anneal. The increase in radiation sensitivity is independent of the emitter polarity or geometry and is most dramatic between the first and second radiation and anneal cycles. In parallel with the current gain measurements, samples from a monitor wafer simulating the screen oxide region above the extrinsic base in the npn transistors were measured for mechanical stress while undergoing similar cycles of irradiation and anneal. The oxide on the monitor wafer consisted of a 45 nm thermal layer and a 640 nm deposited layer. The results indicate that ionizing radiation helped relieve compressive stress at the Si surface. The magnitude of the stress change due to radiation is smaller than the stress induced by the emitter contact metallization followed by a post-metallization anneal. Correlation of radiation sensitivity in the bipolar transistors and mechanical stress in the monitor wafer suggests that mechanical stress may be influential in determining the radiation hardness of bipolar transistors and lends validation to previously reported observations that Si-SiO 2 interfaces are increasingly more susceptible to radiation damage with decreasing Si compressive stress. Possible mechanisms for the observed changes in stress and their effect on the radiation sensitivity of the bipolar transistors are discussed

  11. Assessing Acculturative Stress of International Students at a U.S. Community College

    Science.gov (United States)

    Hansen, Hardaye R.; Shneyderman, Yuliya; McNamara, Gloria S.; Grace, Lisa

    2018-01-01

    Research shows that international college students experience high levels of acculturative stress, which can adversely impact their health and college success. The levels of immersion in one's native culture and the culture of the U.S. may impact levels of acculturative stress in international students. This cross-sectional study examined…

  12. Analysis of Acculturative Stress and Sociocultural Adaptation among International Students at a Non-Metropolitan University

    Science.gov (United States)

    Mahmood, Hajara; Burke, Monica Galloway

    2018-01-01

    This quantitative descriptive study analyzed levels of acculturative stress and sociocultural adaptation among international students at a non-metropolitan university in the United States related to certain demographic characteristics. Surveys were used to measure international students' levels of acculturative stress and sociocultural adaptation,…

  13. Acculturative Stress, Poor Mental Health and Condom-Use Intention among International Students in China

    Science.gov (United States)

    Yang, Ningxi; Xu, Yayun; Chen, Xinguang; Yu, Bin; Yan, Hong; Li, Shiyue

    2018-01-01

    Objectives: Engaging in sexual risk behaviour can be a maladaptive strategy for international students to deal with stress. This study examined the role of poor mental health in mediating the relationship between acculturative stress and condom-use intention among international students in Beijing, China. Methods: The study used a cross-sectional…

  14. Simulation of stresses, residual stresses, and distortion in stepped cylinders of AISI 4140 due to martensitical hardening by immersion cooling

    Energy Technology Data Exchange (ETDEWEB)

    Ehlers, M.; Mueller, H.; Loehe, D. [Karlsruhe Univ. (Germany). Inst. for Materials Science and Engineering I

    1999-09-01

    Heat treatment improves mechanical properties of steel parts, but also causes residual stresses and distortion. Stresses and deformation occurring during heat treatment can not be measured in-situ with appropriate temporal and spatial resolution. In order to evaluate the processes occurring in the workpiece during quenching as well as the residual stresses and distortions, numerical methods have to be used. Heat conduction, phase transformations, and mechanical behaviour of the material as well as the couplings between the processes such as transformation plasticity have to be modeled for the simulation of steel hardening. Temperature and phase dependent properties (including TTT-data) have to incorporated into calculations. One of the major factors determining the evolution of stress and deformation is the heat-transfer coefficient between component and quenching medium. For vapourizing liquids, heat transfer depends on temperature and location. But heat transfer is not only influenced by the quenchant but also by part geometry and size. Stepped cylinders of AISI 4140 steel were quenched in water and oil. Both experimental measurements and numerical calculations were carried out. The variation of dive-in direction strongly influences the rewetting of the specimen surface and therefore the cooling behaviour, stress and deformation evolution, and resultant residual stresses and distortion. Excellent agreement is obtained between calculated and experimental results. (orig.)

  15. Aspects of acculturation stress among international students attending a university in the USA.

    Science.gov (United States)

    Chavajay, Pablo; Skowronek, Jeffrey

    2008-12-01

    Acculturation stress reported by 130 international students attending a university in Utah for about 2 yr. was examined. On the Acculturative Stress Scale for International Students, few students reported experiencing acculturation stress, but responses to four open-ended questions indicated many students perceived experience of acculturation stresses related to discrimination, feelings of loneliness, and academic concerns. The contrast of findings for the scale scores and the open-ended questions indicate the complexity of assessing international students' acculturation experiences of living and studying in the USA and suggest the usefulness of complementary methodologies for assessing such experience.

  16. Pulsating Tonsil Due to Medial Displacement of the Internal Carotid Artery.

    Science.gov (United States)

    Alsini, Albaraa Y; Ibrahim, Alsheikhi

    2017-05-06

    BACKGROUND The internal carotid artery (ICA) is about 2.5 cm away from the tonsils. It has no branches in the cervical portion. ICA anomalies of the neck zone may result in a massive arterial bleeding during pharynx and neck surgery. Due to these anomalies, the surgeon must be aware of this risk during tonsillectomy, adenoidectomy, and pharyngeal operations.  CASE REPORT A 23-year-old woman who was discovered to have an acute S curling-type anomaly of the ICA in contact with the lateral border of the right tonsil during a work-up for a tonsillectomy. This anomaly was incidentally discovered via computed tomography (CT) with contrast. In re-evaluating the course of treatment, we found a severe S-shape kink on the right side, bringing it close to the right tonsil by approximately 2 mm, and putting it at severe risk of injury during a simple tonsillectomy, possibly exposing the patient to serious bleeding. Partial tonsillectomy was performed for this patient with the aim to preserve and not expose the internal carotid artery. Pulsation of right tonsil was recorded. The patient made an uneventful postoperative recovery. CONCLUSIONS Undetected ICA anomaly variation can lead to fatal bleeding during a simple procedure, like tonsillectomy. We recommend vigilance during tonsillectomy if one is using a hot dissection method versus a cold dissection method, which may allow for detection of a perioperative ICA anomaly. Tonsillectomy performed by a junior resident should be under direct supervision, particularly if the hot dissection method is used.

  17. Doses and risk estimates to the human conceptus due to internal prenatal exposure to radioactive caesium

    International Nuclear Information System (INIS)

    Kalef-Ezra, J.A.

    1997-01-01

    The 1986 nuclear reactor accident at Chernobyl resulted in widespread internal contamination by radioactive caesium. The aim of the present study was to estimate the doses to embryos/fetus in Greece attributed to maternal 134 Cs and 137 Cs intake and the consequent health risks to their offspring. In pregnant women the concentration of total-body caesium (TBCs) was lower than in age-matched non-pregnant women measured during the same month. A detailed study of intake and retention in the members of one family carried out during the three years that followed the accident indicated that the biological half-time of caesium in the women decreased by a factor of two shortly after conception. Then at partus, there was an increase in the biological half-time, reaching a value similar to that before conception. The total-body potassium concentration was constant over the entire period. Doses to the embryo/fetus due to maternal intake was estimated to be about 150 μGy maximally in those conceived between November 1986 and March 1987. When conception took place later, the prenatal dose followed an exponential reduction with a half-time of about 170 d. These prenatal doses do not exceed the doses from either the natural internal potassium, or from the usual external background sources. The risks attributed to maternal 134 Cs and 137 Cs intake were considerably lower than levels that would justify consideration of termination of a pregnancy. In the absence of these data however, 2500 otherwise wanted pregnancies in Greece were terminated following the Chernobyl accident. (author)

  18. Perceived Support as a Predictor of Acculturative Stress among International Students in the United States

    Science.gov (United States)

    Bai, Jieru

    2016-01-01

    A quantitative study was conducted to measure the acculturative stress of international students and investigate the predictors of acculturative stress. A total of 186 students participated in the survey. Results showed that 22.4% of the students in this study exceeded the normal stress level and might need counseling or psychological…

  19. Effects of Assertiveness Training and Expressive Writing on Acculturative Stress in International Students: A Randomized Trial

    Science.gov (United States)

    Tavakoli, Shedeh; Lumley, Mark A.; Hijazi, Alaa M.; Slavin-Spenny, Olga M.; Parris, George P.

    2009-01-01

    International university students often experience acculturative stress, and culturally appropriate techniques to manage stress are needed. This randomized trial tested the effects of group assertiveness training, private expressive writing, their combination, and a wait-list control on the acculturative stress, affect, and health of 118…

  20. Self-Critical Perfectionism, Acculturative Stress, and Depression among International Students

    Science.gov (United States)

    Rice, Kenneth G.; Choi, Chun-Chung; Zhang, Yanmei; Morero, Yanina Ines; Anderson, Debra

    2012-01-01

    The authors tested a classic diathesis-stress, stress-enhancement model of perfectionism with subgroups of Chinese (N = 129) and Asian Indian (N = 166) international graduate students attending a major U.S. university. More specifically, the authors tested whether self-critical perfectionism, acculturative stress, and their interaction accounted…

  1. Structural transformations in Mn2NiGa due to residual stress

    International Nuclear Information System (INIS)

    Singh, Sanjay; Maniraj, M.; D'Souza, S. W.; Barman, S. R.; Ranjan, R.

    2010-01-01

    Powder x-ray diffraction study of Mn 2 NiGa ferromagnetic shape memory alloy shows the existence of a 7M monoclinic modulated structure at room temperature (RT). The structure of Mn 2 NiGa is found to be highly dependent on residual stress. For higher stress, the structure is tetragonal at RT, and for intermediate stress it is 7M monoclinic. However, only when the stress is considerably relaxed, the structure is cubic, as is expected at RT since the martensitic transition temperature is 230 K.

  2. Transient thermal stresses due to a zonal heat source moving back and forth over the surface on an infinite plate

    International Nuclear Information System (INIS)

    Sumi, N.; Hetnarski, R.B.

    1989-01-01

    A solution is given for the transient thermal stresses due to a zonal heat source moving back and forth with a constant angular frequency over the surface of an infinite elastic plate. The transient temperature distribution is obtained by using the complex Fourier and Laplace transforms, and the associated thermal stresses are obtained by means of the thermoelastic displacement potential and the Galerkin function. Graphical representations for the solution in dimensionless terms are included in this paper. (orig.)

  3. Evidence for shear stress-mediated dilation of the internal carotid artery in humans

    DEFF Research Database (Denmark)

    Carter, Howard Henry; Atkinson, Ceri L; Heinonen, Ilkka H A

    2016-01-01

    -mediated dilation of larger conduit arteries in humans. There was a strong association between change in shear and diameter of the internal carotid (r=0.68; Ptime in humans, that shear stress is an important stimulus for hypercapnic vasodilation of the internal carotid...... increases carotid shear stress, a known stimulus to vasodilation in other conduit arteries. To explore the hypothesis that shear stress contributes to hypercapnic internal carotid dilation in humans, temporal changes in internal and common carotid shear rate and diameter, along with changes in middle.......01) carotids. Diameter also increased (Ptime course is associated with shear...

  4. Lithospheric stresses due to radiogenic heating of an ice-silicate planetary body - Implications for Ganymede's tectonic evolution

    Science.gov (United States)

    Zuber, M. T.; Parmentier, E. M.

    1984-01-01

    Thermal evolution models of differentiated and undifferentiated ice-silicate bodies containing long-lived radiogenic heat sources are examined. Lithospheric sresses arise due to volume change of the interior and temperature change in the lithosphere. For an undifferentiated body, the surface stress peaks early in the evolution, while in the differentiated case, stresses peak later and continue to accumulate for longer periods of time. The variation of near-surface stress with depth shows that stresses for the undifferentiated body initially penetrate to great depths, but rapidly concentrate within a few kilometers of the surface. For the differentiated body, elastic stresses never accumulate at a depth greater than a few kilometers. These models are applied to consider long-term rdioactive heating as a possible mechanism of tectonic activity and bright terrain formation on Ganymede.

  5. Program of assessment of mechanical and corrosion mechanical properties of reactor internals materials due to operation conditions in WWERs

    International Nuclear Information System (INIS)

    Ruscak, M.; Zamboch, M.

    1998-01-01

    Reactor internals are subject to three principle operation influences: neutron and gamma irradiation, mechanical stresses, both static and dynamic, and coolant chemistry. Several cases of damage have been reported in previous years in both boiling and pressure water reactors. They are linked with the term of irradiation assisted stress corrosion cracking as a possible damage mechanism. In WWERs, the principal material used for reactor internals is austenitic titanium stabilized stainless steel 08Kh18N10T, however high strength steels are used as well. To assess the changes of mechanical properties and to determine whether sensitivity to intergranular cracking can be increased by high neutron fluences, the experimental program has been started. The goal is to assure safe operation of the internals as well as life management for all planned operation period. The program consists of tests of material properties, both mechanical and corrosion-mechanical. Detailed neutron fluxes calculation as well as stress and deformation calculations are part of the assessment. Model of change will be proposed in order to plan inspections of the facility. In situ measurements of internals will be used to monitor exact status of structure during operation. Tensile specimens manufactured from both base metal and model weld joint have been irradiated to the total fluences of 3-20 dpa. Changes of mechanical properties are tested by the tensile test, stress corrosion cracking tests are performed in the autoclave with water loop and active loading. Operation temperature, pressure and water chemistry are chosen for the tests. (author)

  6. Work stress and emotional exhaustion in nurses: the mediating role of internal locus of control.

    Science.gov (United States)

    Partlak Günüşen, Neslihan; Ustün, Besti; Erdem, Sabri

    2014-01-01

    Burnout is a major problem for nursing. There is a strong relationship between work stress and emotional exhaustion. Although studies report a negative correlation between the internal locus of control and emotional exhaustion and work stress, the number of studies available on the subject is limited. This study intends to examine the extent to which the relationship between work stress and emotional exhaustion is mediated by nurses' internal locus of control. The study adopted a cross-sectional survey design. The data were analyzed using structural equation modeling techniques. The study sample consisted of 347 nurses who worked in a university hospital in Izmir, Turkey and who agreed to participate in the study. The Work-Related Strain Inventory was used to evaluate the nurses' work stress level, Maslach Burnout Inventory was used to evaluate their emotional exhaustion levels, and the Locus of Control Scale was used to evaluate the internal locus of control. The variables of the study were based on the Neuman Systems Model. Work stress was positively related to internal locus of control (β3 = .21, p 0.1). Internal locus of control was negatively related to emotional exhaustion (β = -.14, p Work stress is directly (β = .87, p Work stress is directly (β = .87, p work stress was mediated, the impact of internal locus of control was limited. It is recommended that different variables be included in future studies so that they can mediate the relationship between work stress and emotional exhaustion.

  7. Quantifying uncertainty due to internal variability using high-resolution regional climate model simulations

    Science.gov (United States)

    Gutmann, E. D.; Ikeda, K.; Deser, C.; Rasmussen, R.; Clark, M. P.; Arnold, J. R.

    2015-12-01

    The uncertainty in future climate predictions is as large or larger than the mean climate change signal. As such, any predictions of future climate need to incorporate and quantify the sources of this uncertainty. One of the largest sources comes from the internal, chaotic, variability within the climate system itself. This variability has been approximated using the 30 ensemble members of the Community Earth System Model (CESM) large ensemble. Here we examine the wet and dry end members of this ensemble for cool-season precipitation in the Colorado Rocky Mountains with a set of high-resolution regional climate model simulations. We have used the Weather Research and Forecasting model (WRF) to simulate the periods 1990-2000, 2025-2035, and 2070-2080 on a 4km grid. These simulations show that the broad patterns of change depicted in CESM are inherited by the high-resolution simulations; however, the differences in the height and location of the mountains in the WRF simulation, relative to the CESM simulation, means that the location and magnitude of the precipitation changes are very different. We further show that high-resolution simulations with the Intermediate Complexity Atmospheric Research model (ICAR) predict a similar spatial pattern in the change signal as WRF for these ensemble members. We then use ICAR to examine the rest of the CESM Large Ensemble as well as the uncertainty in the regional climate model due to the choice of physics parameterizations.

  8. Stress in film/substrate system due to diffusion and thermal misfit effects

    International Nuclear Information System (INIS)

    Shao Shanshan; Xuan Fuzhen; Wang Zhengdong; Tu Shantung

    2009-01-01

    The stress in film/substrate systems has been analysed taking into consideration the coupling effects of diffusion and thermal misfit within the framework of Fick's second law. The solution of diffusion-induced stress in a film/substrate system involving the thermal misfit stress feedback is developed. The effects of modulus ratios, diffusivity ratios, thickness ratios of the substrate and the film and the partial molar volume of the diffusing component on the stress distribution in the film/substrate system are then discussed with the help of the finite difference method. Results indicate that the stresses in the film/substrate system vary with diffusion time. Diffusion enhances the magnitudes of film stress when the thermal misfit stress is compressive in the film. Furthermore, the absolute values of stress in the film increase with the increasing modulus ratios of the substrate and film, while they reduce with the increasing partial molar volume of the diffusing component and the diffusivity ratio of the substrate and the film.

  9. Coping, perceived stress, and job satisfaction among medical interns: The mediating effect of mindfulness

    Directory of Open Access Journals (Sweden)

    M Vinothkumar

    2016-01-01

    Full Text Available Background: Past research studies on the exploration of attributes to the stress of doctors/medical interns were reported more often than the types of coping strategies, healthy practices to strengthen their internal resources to deal effectively with the stressful situations. Objectives: The present study was conducted to find such internal resource – “mindfulness” as a mediator of coping, perceived stress, and job satisfaction among medical interns. Methods: A cross-sectional descriptive study comprised 120 medical interns forms from various medical colleges in Mangalore were recruited and completed the assessment on mindfulness, cognitive-emotive regulation, coping strategies, perceived stress, and job satisfaction from doctoral interns were collected. Results: Initial correlation analysis results indicate that adaptive coping strategies significantly associate with greater mindfulness and less perceived stress. In turn, mindfulness is negatively correlated with nonadaptive coping strategies and perceived. Job satisfaction showed no significant relationship with any of the other variables. Mediational models indicate that the relationship between adaptive coping strategies and perceived stress was significantly mediated by mindfulness. Furthermore, partial mediation between nonadaptive strategies and perceived stress through mindfulness indicates that respondents reported a high level of nonadaptive strategy experience and a lower level of mindfulness can be counterproductive as they encourage the ineffective way to deal with the stresses. Conclusion: The implication of the results were discussed with suggesting a possible intervention to improve the adaptive strategies and mindfulness among the medical interns.

  10. Coping, perceived stress, and job satisfaction among medical interns: The mediating effect of mindfulness.

    Science.gov (United States)

    Vinothkumar, M; Arathi, A; Joseph, Merin; Nayana, Prasad; Jishma, E Joshy; Sahana, U

    2016-01-01

    Past research studies on the exploration of attributes to the stress of doctors/medical interns were reported more often than the types of coping strategies, healthy practices to strengthen their internal resources to deal effectively with the stressful situations. The present study was conducted to find such internal resource - "mindfulness" as a mediator of coping, perceived stress, and job satisfaction among medical interns. A cross-sectional descriptive study comprised 120 medical interns forms from various medical colleges in Mangalore were recruited and completed the assessment on mindfulness, cognitive-emotive regulation, coping strategies, perceived stress, and job satisfaction from doctoral interns were collected. Initial correlation analysis results indicate that adaptive coping strategies significantly associate with greater mindfulness and less perceived stress. In turn, mindfulness is negatively correlated with nonadaptive coping strategies and perceived. Job satisfaction showed no significant relationship with any of the other variables. Mediational models indicate that the relationship between adaptive coping strategies and perceived stress was significantly mediated by mindfulness. Furthermore, partial mediation between nonadaptive strategies and perceived stress through mindfulness indicates that respondents reported a high level of nonadaptive strategy experience and a lower level of mindfulness can be counterproductive as they encourage the ineffective way to deal with the stresses. The implication of the results were discussed with suggesting a possible intervention to improve the adaptive strategies and mindfulness among the medical interns.

  11. A finite element elastic-plastic analysis of residual stresses due to clad welding in reactor vessels

    International Nuclear Information System (INIS)

    Buchalet, C.; Riccardella, P.C.

    1972-01-01

    Residual stresses due to weld deposited cladding on the inside of a typical Westinghouse pressurized water reactor vessel are investigated using an axisymmetric finite element elastic-plastic analysis. At the beginning of the analysis, one head of the weld cladding is assumed to lie on the reactor vessel wall at melting temperature (2600degF), but in the solid phase, while the vessel remains at 300degF (preheat temperature). All material properties used in the calculations are taken as temperature-dependent. Temperature profiles are obtained in the cladding and base metal at several discrete time intervals. These temperatures profiles are used to obtain the stress distribution for the same time intervals. Residual hoop tensile stresses of approximately 25 ksi were found to exist in the cladding. Peak tensile stresses in the hoop direction occur in the base metal near the cladding interface and reach a value of 60 ksi at the end of the transient. The tensile stress decreases very rapidly through the thickness of the base metal and becomes insignificant at about two inches from the inside surface. In order to lower residual stresses, a post-weld heat treatment is performed by uniformly heating the vessel to 1100degF, holding at that temperature for a specified period of time and then cooling slowly. The analysis shows that after this treatment, the peak stresses in the base metal decrease from 60 ksi to 32 ksi, while the stress in the cladding does not change significantly. (author)

  12. Dynamic stress relaxation due to cyclic variation of strain at elevated temperature

    International Nuclear Information System (INIS)

    Suzuki, F.

    1975-01-01

    The relaxation of stress which occurs when low amplitude alternating strains are superimposed on constant mean total strains is studied in this paper. Experiments were carried out on a 0.16 per cent carbon steel and an AISI 347 stainless steel at 450 0 C and 650 0 C respectively in which the decrease of axial mean stress was measured as a function of time. When even a low amplitude alternating strain was applied, the rate of stress relaxation was observed to increase. Analytical predictions based on creep and static relaxation data show fairly good agreement with experiments in the period corresponding to transient creep. (author)

  13. Potential of future seismogenesis in Hebei Province (NE China) due to stress interactions between strong earthquakes

    Science.gov (United States)

    Karakostas, Vassilios; Papadimitriou, Eleftheria; Jin, Xueshen; Liu, Zhihui; Paradisopoulou, Parthena; He, Zhang

    2013-10-01

    Northeast China, a densely populated area, is affected by intense seismic activity, which includes large events that caused extensive disaster and tremendous loss of life. For contributing to the continuous efforts for seismic hazard assessment, the earthquake potential from the active faults near the cities of Zhangjiakou and Langfang in Hebei Province is examined. We estimate the effect of the coseismic stress changes of strong (M ⩾ 5.0) earthquakes on the major regional active faults, and mapped Coulomb stress change onto these target faults. More importantly our calculations reveal that positive stress changes caused by the largest events of the 1976 Tangshan sequence make the Xiadian and part of Daxing fault, thus considered the most likely sites of the next strong earthquake in the study area. The accumulated static stress changes that reached a value of up to 0.4 bar onto these faults, were subsequently incorporated in earthquake probability estimates for the next 30 years.

  14. Acute pulmonary edema due to stress cardiomyopathy in a patient with aortic stenosis: a case report

    OpenAIRE

    Bayer, Monika F

    2009-01-01

    Introduction Stress cardiomyopathy is a condition of chest pain, breathlessness, abnormal heart rhythms and sometimes congestive heart failure or shock precipitated by intense mental or physical stress. Case presentation A 64-year-old male with a known diagnosis of moderate-to-severe aortic stenosis and advised that valve replacement was not urgent, presented with acute pulmonary edema following extraordinary mental distress. The patient was misdiagnosed as having a "massive heart attack" and...

  15. Physical work load and psychological stress of daily activities as predictors of disability pension due to musculoskeletal disorders.

    Science.gov (United States)

    Ropponen, Annina; Svedberg, Pia; Koskenvuo, Markku; Silventoinen, Karri; Kaprio, Jaakko

    2014-06-01

    Physical work loading and psychological stress commonly co-occur in working life, hence potentially having an interrelationship that may affect work incapacity. This prospective cohort study aimed to investigate the effect of stability and change in physical work loading and stress on the risk of disability pension (DP) due to musculoskeletal diagnoses (MSD), while accounting for familial confounding in these associations. Data on 12,455 twins born before 1958 were surveyed of their physical work loading and psychological stress of daily activities in 1975 and 1981. The follow-up data was collected from pension registers until 2004. Cox proportional hazards regression models were used. During the follow up, 893 participants were granted DP due to MSD. Stable high (hazard ratio, HR, 2.21), but also increased physical work loading (HR 2.05) and high psychological stress (HR 2.22) were associated with increased risk for DP, and had significant interaction (p=0.032). The associations were confirmed when accounting for several confounding factors. Stable high but also increased physical work loading and psychological stress of daily activities between two timepoints with 6 years apart confirms their predictive role for an increased risk of DP. Both physical work loading and psychological stress seem to be independent from various confounding factors hence suggesting direct effect on risk for DP providing potential for occupational health care to early identification of persons at risk. © 2014 the Nordic Societies of Public Health.

  16. Residual and working stresses in pipe joints in heterogeneous metals, due to common action of welding and service loads

    International Nuclear Information System (INIS)

    Kiselev, S.N.; Voronin, N.N.; Roshchin, V.V.

    1978-01-01

    The stresses in the welded joints of cylindrical shells are studied, which are caused by the total effect of the thermal deformation welding cycles, by the preheats connected with the thermal treatment or operation, and by power loads. Studied were the shell joints made of the steels Kh18N10T and St.3, as well as the joints of three shells made of different metals, St.3+18N1aT steel+copper. The schematic diagram showing the residual stresses set up under effect of different factors are presented. The following has been shown by the study: the preheating of the welded joints of the shells made of diverse metals up to the operational temperatures does not result in obviating the residual stresses. If the welded shells are loaded by the internal pressure up to the stresses of (0.8-O.9) sigmasub(T), in certain cases an essential (up to 60-70%) reduction in the residual welding stresses may be obtained. The effectiveness of a variation in the residual stresses is reduced in the joints that have been thermally treated after welding. The working stresses set up in the welded joints of the shells made of different metals under the operational loading may be essentially reduced through initial preheating with the application of a pressure or without it. The preheating temperature and the pressures applied may be chosen so that to create the residual strains and the stresses of inverse sign as compared with the working stresses

  17. Stress and coping strategies among nursing students: an international study.

    Science.gov (United States)

    Labrague, Leodoro J; McEnroe-Petitte, Denise M; Papathanasiou, Ioanna V; Edet, Olaide B; Tsaras, Konstantinos; Leocadio, Michael C; Colet, Paolo; Kleisiaris, Christos F; Fradelos, Evangelos C; Rosales, Rheajane A; Vera Santos-Lucas, Katherine; Velacaria, Pearl Irish T

    2017-12-20

    Mounting literature on stress and coping in nursing students are available; however, most of the findings are confined to a single cultural group. This study was conducted to determine the level of stress, its sources and coping strategies among nursing students from three countries: Greece, the Philippines and Nigeria. Using a descriptive, comparative research design, 547 nursing students (161 Greek nursing students, 153 Filipino nursing students, 233 Nigerian nursing students) participated in the study from August 2015 to April 2016. Two standardized instruments were used, the Perceived Stress Scale (PSS) and the Coping Behavior Inventory (CBI). Findings revealed that the degree of stress and the type of stressors and coping styles utilized by nursing students differ according to the country of origin. The year of study predicted overall stress (β = -0.149, p stress and lessen its impact such as stress management counseling, counseling programs, establishing peer and family support systems, and formulating hospital policies that will support nursing students.

  18. Coupling analysis of the target temperature and thermal stress due to pulsed ion beam

    International Nuclear Information System (INIS)

    Yan Jie; Liu Meng; Lin Jufang; An Li; Long Xinggui

    2013-01-01

    Background: Target temperature has an important effect on the target life for the sealed neutron generator without cooling system. Purpose: To carry out the thermal-mechanical coupling analysis of the film-substrate target bombarded by the pulsed ion beam. Methods: The indirect coupling Finite Element Method (FEM) with a 2-dimensional time-space Gaussian axisymmetric power density as heat source was used to simulate the target temperature and thermal stress fields. Results: The effects of the target temperature and thermal stress fields under difference pulse widths and beam sizes were analyzed in terms of the FEM results. Conclusions: Combining with the temperature requirement and the thermal stress inducing film thermal mechanical destruction effect of the sealed neutron generator film-substrate targets, an optimized pulsed ion beam work status was proposed. (authors)

  19. Measurement of probability distributions for internal stresses in dislocated crystals

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, Angus J.; Tarleton, Edmund; Vilalta-Clemente, Arantxa; Collins, David M. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Jiang, Jun; Britton, T. Benjamin [Department of Materials, Imperial College London, Royal School of Mines, Exhibition Road, London SW7 2AZ (United Kingdom)

    2014-11-03

    Here, we analyse residual stress distributions obtained from various crystal systems using high resolution electron backscatter diffraction (EBSD) measurements. Histograms showing stress probability distributions exhibit tails extending to very high stress levels. We demonstrate that these extreme stress values are consistent with the functional form that should be expected for dislocated crystals. Analysis initially developed by Groma and co-workers for X-ray line profile analysis and based on the so-called “restricted second moment of the probability distribution” can be used to estimate the total dislocation density. The generality of the results are illustrated by application to three quite different systems, namely, face centred cubic Cu deformed in uniaxial tension, a body centred cubic steel deformed to larger strain by cold rolling, and hexagonal InAlN layers grown on misfitting sapphire and silicon carbide substrates.

  20. Job stress, satisfaction, and coping strategies among medical interns in a South Indian tertiary hospital.

    Science.gov (United States)

    Chandramouleeswaran, Susmita; Edwin, Natasha C; Braganza, Deepa

    2014-07-01

    It has previously been demonstrated that there is a significant drop in all domains of quality of life among interns during internship. A modified version of the health consultant's job stress and satisfaction questionnaire (HCJSSQ) was used to assess and quantify aspects of internship that were perceived as stressful and satisfying. Methods used to cope with work place stress were explored. A prospective cohort study was undertaken among 93 medical interns doing a rotating internship at the Christian Medical College and Hospital, a tertiary-care hospital in southern India. After completion of 6 months of internship, the modified version of the HCJSSQ was administered to all participants. The data were entered into Statistical Package for the Social Sciences (SPSS) Version 9 by double data entry technique. Percentages of interns reporting high levels of stress, satisfaction were calculated. While 63.4% of interns reported high levels of satisfaction, 45.2% of the interns experienced high levels of stress, 17.6% coped with work stress by using alcohol and nicotine, and 37% coped through unhealthy eating habits. More people found internship satisfying than stressful. However, a high proportion found it stressful, and many reported unhealthy coping mechanisms.

  1. The Co-Development of Parenting Stress and Childhood Internalizing and Externalizing Problems.

    Science.gov (United States)

    Stone, Lisanne L; Mares, Suzanne H W; Otten, Roy; Engels, Rutger C M E; Janssens, Jan M A M

    Although the detrimental influence of parenting stress on child problem behavior is well established, it remains unknown how these constructs affect each other over time. In accordance with a transactional model, this study investigates how the development of internalizing and externalizing problems is related to the development of parenting stress in children aged 4-9. Mothers of 1582 children participated in three one-year interval data waves. Internalizing and externalizing problems as well as parenting stress were assessed by maternal self-report. Interrelated development of parenting with internalizing and externalizing problems was examined using Latent Growth Modeling. Directionality of effects was further investigated by using cross-lagged models. Parenting stress and externalizing problems showed a decrease over time, whereas internalizing problems remained stable. Initial levels of parenting stress were related to initial levels of both internalizing and externalizing problems. Decreases in parenting stress were related to larger decreases in externalizing problems and to the (stable) course of internalizing problems. Some evidence for reciprocity was found such that externalizing problems were associated with parenting stress and vice versa over time, specifically for boys. Our findings support the transactional model in explaining psychopathology.

  2. The Role of Stress Exposure and Family Functioning in Internalizing Outcomes of Urban Families.

    Science.gov (United States)

    Sheidow, Ashli J; Henry, David B; Tolan, Patrick H; Strachan, Martha K

    2014-11-01

    Although research suggests that stress exposure and family functioning are associated with internalizing problems in adolescents and caregivers, surprisingly few studies have investigated the mechanisms that underlie this association. To determine whether family functioning buffers the development of internalizing problems in stress-exposed families, we assessed the relation between stress exposure, family functioning, and internalizing symptoms among a large sample of inner-city male youth and their caregivers living in poverty across five waves of data collection. We hypothesized that stress exposure and family functioning would predict development of subsequent youth and caregiver internalizing problems and that family functioning would moderate this relation, with higher functioning families demonstrating greater resiliency to stress exposure. We used a longitudinal, prospective design to evaluate whether family functioning (assessed at waves one through four) activated or buffered the effects of stress exposure (assessed at wave one) on subsequent internalizing symptoms (assessed at waves four and five). Stress from Developmental Transitions and family functioning were significant predictors of depressive symptoms and anxiety in youth; however, family functioning did not moderate the relation. Family functioning mediated the relation between stress from Daily Hassles and internalizing outcomes suggesting that poor parenting practices, low structure, and low emotional cohesion activate depression and anxiety in youth exposed to chronic and frequent everyday stressors. Surprisingly, only family functioning predicted depressive symptoms in caregivers. Results validate the use of a comprehensive, multi-informant assessment of stress when investigating internalizing outcomes in youth and support using family-based interventions in the treatment and prevention of internalizing.

  3. Flow effects due to pulsation in an internal combustion engine exhaust port

    International Nuclear Information System (INIS)

    Semlitsch, Bernhard; Wang, Yue; Mihăescu, Mihai

    2014-01-01

    Highlights: • Using POD analysis to identify large coherent flow structures in a complex geometry. • Flow field alters significant for constant and pulsating boundary conditions. • The discharge coefficient of the exhaust port decreases 2% with flow pulsation. • Pulsation causes a pumping mechanism due to a phase shift of pressure and momentum. - Abstract: In an internal combustion engine, the residual energy remaining after combustion in the exhaust gasses can be partially recovered by a downstream arranged device. The exhaust port represents the passage guiding the exhaust gasses from the combustion chamber to the energy recovering device, e.g. a turbocharger. Thus, energy losses in the course of transmission shall be reduced as much as possible. However, in one-dimensional engine models used for engine design, the exhaust port is reduced to its discharge coefficient, which is commonly measured under constant inflow conditions neglecting engine-like flow pulsation. In this present study, the influence of different boundary conditions on the energy losses and flow development during the exhaust stroke are analyzed numerically regarding two cases, i.e. using simple constant and pulsating boundary conditions. The compressible flow in an exhaust port geometry of a truck engine is investigated using three-dimensional Large Eddy Simulations (LES). The results contrast the importance of applying engine-like boundary conditions in order to estimate accurately the flow induced losses and the discharge coefficient of the exhaust port. The instantaneous flow field alters significantly when pulsating boundary conditions are applied. Thus, the induced losses by the unsteady flow motion and the secondary flow motion are increased with inflow pulsations. The discharge coefficient decreased about 2% with flow pulsation. A modal flow decomposition method, i.e. Proper Orthogonal Decomposition (POD), is used to analyze the coherent structures induced with the particular

  4. On the Internal Structure of Mobile Barchan Sand Dunes due to Granular Processes

    Science.gov (United States)

    Vriend, N. M.; Arran, M.; Louge, M. Y.; Hay, A. G.; Valance, A.

    2017-12-01

    In this work, we visualize the internal structure of mobile barchan desert dunes at the avalanche scale. We reveal an intriguing history of dune building using a novel combination of local sand sampling and advanced geophysical techniques resulting in high resolution measurements of individual avalanche events. Due to progressive rebuilding, granular avalanching, erosional and depositional processes, these marching barchan dunes are reworked every few years and a characteristic zebra-pattern (figure 1a), orientated parallel to the slipface at the angle of repose, appears at regular intervals. We present scientific data on the structure obtained from several mobile barchan dunes of different sizes during recent desert field campaigns (2014, 2015, 2017) in a mobile barchan dune field in Qatar (25.01°N, 51.34°E in the AlWakrah municipality). The site has been equipped with a weather station and has been regularly visited by a multidisciplinary research team in recent years (e.g. [1]). By applying high-frequency (1200 MHz) ground penetrating radar (GPR) transects across the midline (figure 1b) we map the continuous evolution of this cross-bedding at high resolution deep within the dune. The GPR reveals a slope reduction of the slipface near the base of the dune; evidence of irregular wind reversals; and the presence of a harder aeolian cap around the crest and extending to the brink. The data is supplemented with granulometry from layers stabilized by dyed water injection and uncovered by excavating vertical walls perpendicular to old buried avalanches. We attribute visible differences in water penetration between adjacent layers to fine particle segregation processes in granular avalanches. This work was made possible by the support of NPRP grant 6-059-2-023 from the Qatar National Research Fund to MYL and AGH, and a Royal Society Dorothy Hodgkin Research Fellowship to NMV. We thank Jean-Luc Métayer for performing detailed particle size distribution measurements

  5. internal radiation dose assessment due to ionizing radio contaminants in some local foodstuffs

    International Nuclear Information System (INIS)

    AbdElKader, F.M.

    1996-01-01

    Over the last 30 years, radioactivity has been monitored in foodstuffs in Egypt. The present work deals with the radioactivity monitored during two years (1990 - 1992) at eight major Egyptian governorates. Sampled food items were selected to cover most foodstuffs eaten by egyptian population according to their habits. The daily food consumption by egyptian population and the constituents of such consumption were estimated according to published international data and knowledge of the different feeding habits of the egyptians. About 1200 samples were collected from the markets of the main city of each governorate and prepared for counting according to the egyptian kitchen habits. The counting systems used in determination and indentification of radionuclides were : a 3 inch HPGe detector attached to 800 channel MCA and PC and a 3 inch phoswich detector attached to an anticoincidence circuit for low beta / gamma counting. The gamma spectroscopy system was calibrated using isotopic solution mixture while the low beta counting system was calibrated using H CI. Counting time for the first system was 20 - 72 hours and for the second system was half to one hour. The main radionuclides identified in foodstuffs were Cs - 137 and K - 40 . The radioactivity concentration of Cs - 137 was found to be in the range between 1.0 Bq / Kg for macaroni and 3.5 Bq / Kg for nile beans. The K - 40 concentration range between 19 Bq / Kg for macaroni to 363 Bq / Kg for nile beans. The population weighted values in case of Cs - 137 was found as 3.56 Bq /d and for K - 40 was 188 Bq /d. The resulted effective dose due to food intake was found be 16 . 4 U Sv /a for Cs-137 and 354 μSv / a for K -40 . This value for Cs - 137 is found in the exemption limit while that of K -40 is twice the published value. This may depend on the egyptian feeding habit which depends mainly on wheat (bread) and nile beans which are very rich in potassium.The resulted collective dose was found to be : 21323 person

  6. Honey bee (Apis mellifera) drones survive oxidative stress due to increased tolerance instead of avoidance or repair of oxidative damage.

    Science.gov (United States)

    Li-Byarlay, Hongmei; Huang, Ming Hua; Simone-Finstrom, Michael; Strand, Micheline K; Tarpy, David R; Rueppell, Olav

    2016-10-01

    Oxidative stress can lead to premature aging symptoms and cause acute mortality at higher doses in a range of organisms. Oxidative stress resistance and longevity are mechanistically and phenotypically linked; considerable variation in oxidative stress resistance exists among and within species and typically covaries with life expectancy. However, it is unclear whether stress-resistant, long-lived individuals avoid, repair, or tolerate molecular damage to survive longer than others. The honey bee (Apis mellifera L.) is an emerging model system that is well-suited to address this question. Furthermore, this species is the most economically important pollinator, whose health may be compromised by pesticide exposure, including oxidative stressors. Here, we develop a protocol for inducing oxidative stress in honey bee males (drones) via Paraquat injection. After injection, individuals from different colony sources were kept in common social conditions to monitor their survival compared to saline-injected controls. Oxidative stress was measured in susceptible and resistant individuals. Paraquat drastically reduced survival but individuals varied in their resistance to treatment within and among colony sources. Longer-lived individuals exhibited higher levels of lipid peroxidation than individuals dying early. In contrast, the level of protein carbonylation was not significantly different between the two groups. This first study of oxidative stress in male honey bees suggests that survival of an acute oxidative stressor is due to tolerance, not prevention or repair, of oxidative damage to lipids. It also demonstrates colony differences in oxidative stress resistance that might be useful for breeding stress-resistant honey bees. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Measurement of lattice rotations and internal stresses in over one hundred individual grains during a stress-induced martensitic transformation

    Directory of Open Access Journals (Sweden)

    Hachi Younes El

    2015-01-01

    Full Text Available To better understand the properties of polycrystals at a microscopic scale during cyclic mechanical loading we have measured the relationship between grain orientations, their positions inside the sample and their internal stresses. In this work, in-situ 3DXRD technique was performed on over hundred grains during the stress-induced martensitic transformation in a Cu-Al-Be shape memory alloy. Information about the position, orientation, and stress field was obtained for each austenitic grain. These results have been used to develop a procedure that allows automatic processing for a large number of grains, matching them during loading and leads to a quantitative stress field. A strong heterogeneity of stress state between the grains at the surface and in the volume is evident.

  8. Initialization shock in decadal hindcasts due to errors in wind stress over the tropical Pacific

    Science.gov (United States)

    Pohlmann, Holger; Kröger, Jürgen; Greatbatch, Richard J.; Müller, Wolfgang A.

    2017-10-01

    Low prediction skill in the tropical Pacific is a common problem in decadal prediction systems, especially for lead years 2-5 which, in many systems, is lower than in uninitialized experiments. On the other hand, the tropical Pacific is of almost worldwide climate relevance through its teleconnections with other tropical and extratropical regions and also of importance for global mean temperature. Understanding the causes of the reduced prediction skill is thus of major interest for decadal climate predictions. We look into the problem of reduced prediction skill by analyzing the Max Planck Institute Earth System Model (MPI-ESM) decadal hindcasts for the fifth phase of the Climate Model Intercomparison Project and performing a sensitivity experiment in which hindcasts are initialized from a model run forced only by surface wind stress. In both systems, sea surface temperature variability in the tropical Pacific is successfully initialized, but most skill is lost at lead years 2-5. Utilizing the sensitivity experiment enables us to pin down the reason for the reduced prediction skill in MPI-ESM to errors in wind stress used for the initialization. A spurious trend in the wind stress forcing displaces the equatorial thermocline in MPI-ESM unrealistically. When the climate model is then switched into its forecast mode, the recovery process triggers artificial El Niño and La Niña events at the surface. Our results demonstrate the importance of realistic wind stress products for the initialization of decadal predictions.

  9. Oxidative Stress in the Developing Rat Brain due to Production of Reactive Oxygen and Nitrogen Species

    Czech Academy of Sciences Publication Activity Database

    Wilhelm, Jiří; Vytášek, Richard; Uhlík, Jiří; Vajner, Luděk

    2016-01-01

    Roč. 2016, č. 2016 (2016), č. článku 5057610. ISSN 1942-0900 R&D Projects: GA ČR(CZ) GAP303/11/0298 Institutional support: RVO:67985823 Keywords : oxidative stress * developing rat brain * lipid peroxidation Subject RIV: ED - Physiology Impact factor: 4.593, year: 2016

  10. Genome-wide association of changes in swine feeding behaviour due to heat stress

    Science.gov (United States)

    Background: Heat stress has a negative impact on pork production, particularly during the grow-finish phase. As temperature increases, feeding behaviour changes in order for pigs to decrease heat production. The objective of this study was to identify genetic markers associated with changes in feedi...

  11. Impact of phytopathogen infection and extreme weather stress on internalization of Salmonella Typhimurium in lettuce.

    Science.gov (United States)

    Ge, Chongtao; Lee, Cheonghoon; Nangle, Ed; Li, Jianrong; Gardner, David; Kleinhenz, Matthew; Lee, Jiyoung

    2014-01-03

    Internalization of human pathogens, common in many types of fresh produce, is a threat to human health since the internalized pathogens cannot be fully inactivated/removed by washing with water or sanitizers. Given that pathogen internalization can be affected by many environmental factors, this study was conducted to investigate the influence of two types of plant stress on the internalization of Salmonella Typhimurium in iceberg lettuce during pre-harvest. The stresses were: abiotic (water stress induced by extreme weather events) and biotic (phytopathogen infection by lettuce mosaic virus [LMV]). Lettuce with and without LMV infection were purposefully contaminated with green fluorescence protein-labeled S. Typhimurium on the leaf surfaces. Lettuce was also subjected to water stress conditions (drought and storm) which were simulated by irrigating with different amounts of water. The internalized S. Typhimurium in the different parts of the lettuce were quantified by plate count and real-time quantitative PCR and confirmed with a laser scanning confocal microscope. Salmonella internalization occurred under the conditions outlined above; however internalization levels were not significantly affected by water stress alone. In contrast, the extent of culturable S. Typhimurium internalized in the leafy part of the lettuce decreased when infected with LMV under water stress conditions and contaminated with high levels of S. Typhimurium. On the other hand, LMV-infected lettuce showed a significant increase in the levels of culturable bacteria in the roots. In conclusion, internalization was observed under all experimental conditions when the lettuce surface was contaminated with S. Typhimurium. However, the extent of internalization was only affected by water stress when lettuce was infected with LMV. © 2013.

  12. Heavy Metal Stress, Signaling, and Tolerance Due to Plant-Associated Microbes: An Overview

    Science.gov (United States)

    Tiwari, Shalini; Lata, Charu

    2018-01-01

    Several anthropogenic activities including mining, modern agricultural practices, and industrialization have long-term detrimental effect on our environment. All these factors lead to increase in heavy metal concentration in soil, water, and air. Soil contamination with heavy metals cause several environmental problems and imparts toxic effect on plant as well as animals. In response to these adverse conditions, plants evolve complex molecular and physiological mechanisms for better adaptability, tolerance, and survival. Nowadays conventional breeding and transgenic technology are being used for development of metal stress resistant varieties which, however, are time consuming and labor intensive. Interestingly the use of microbes as an alternate technology for improving metal tolerance of plants is gaining momentum recently. The use of these beneficial microorganisms is considered as one of the most promising methods for safe crop-management practices. Interaction of plants with soil microorganisms can play a vital role in acclimatizing plants to metalliferous environments, and can thus be explored to improve microbe-assisted metal tolerance. Plant-associated microbes decrease metal accumulation in plant tissues and also help to reduce metal bioavailability in soil through various mechanisms. Nowadays, a novel phytobacterial strategy, i.e., genetically transformed bacteria has been used to increase remediation of heavy metals and stress tolerance in plants. This review takes into account our current state of knowledge of the harmful effects of heavy metal stress, the signaling responses to metal stress, and the role of plant-associated microbes in metal stress tolerance. The review also highlights the challenges and opportunities in this continued area of research on plant–microbe–metal interaction. PMID:29681916

  13. Heavy Metal Stress, Signaling, and Tolerance Due to Plant-Associated Microbes: An Overview

    Directory of Open Access Journals (Sweden)

    Shalini Tiwari

    2018-04-01

    Full Text Available Several anthropogenic activities including mining, modern agricultural practices, and industrialization have long-term detrimental effect on our environment. All these factors lead to increase in heavy metal concentration in soil, water, and air. Soil contamination with heavy metals cause several environmental problems and imparts toxic effect on plant as well as animals. In response to these adverse conditions, plants evolve complex molecular and physiological mechanisms for better adaptability, tolerance, and survival. Nowadays conventional breeding and transgenic technology are being used for development of metal stress resistant varieties which, however, are time consuming and labor intensive. Interestingly the use of microbes as an alternate technology for improving metal tolerance of plants is gaining momentum recently. The use of these beneficial microorganisms is considered as one of the most promising methods for safe crop-management practices. Interaction of plants with soil microorganisms can play a vital role in acclimatizing plants to metalliferous environments, and can thus be explored to improve microbe-assisted metal tolerance. Plant-associated microbes decrease metal accumulation in plant tissues and also help to reduce metal bioavailability in soil through various mechanisms. Nowadays, a novel phytobacterial strategy, i.e., genetically transformed bacteria has been used to increase remediation of heavy metals and stress tolerance in plants. This review takes into account our current state of knowledge of the harmful effects of heavy metal stress, the signaling responses to metal stress, and the role of plant-associated microbes in metal stress tolerance. The review also highlights the challenges and opportunities in this continued area of research on plant–microbe–metal interaction.

  14. Behavior of surface residual stress in explosion hardened high manganese austenitic cast steel due to repeated impact loads

    International Nuclear Information System (INIS)

    Oda, Akira; Miyagawa, Hideaki

    1985-01-01

    Explosion hardened high manganese austenitic cast steel is being tried for rail crossing recently. From the previous studies, it became clear that high tensile residual stress was generated in the hardened surface layer by explosion and microcracks were observed. In this study, therefore, the behavior of surface residual stress in explosion hardened steel due to repeated impact loads was examined and compared with those of the original and shot peened steels. The results obtained are summarized as follows: (1) In the initial stage of the repetition of impact, high tensile surface residual stress in explosion hardened steel decreased rapidly with the repetition of impact, while those of the original and shot peened steels increased rapidly. This difference was attributed to the difference in depth of the work hardened layer in three testing materials. (2) Beyond 20 impacts the residual stress of three test specimens decreased gradually, and at more than 2000 impacts the compressive stress of about 500 MPa was produced regardless of the histories of working of testing materials. (3) The linear law in the second stage of residual stress fading was applicable to this case, and the range of the linear relationship was related to the depth of the work hardened layer of testing material. (4) From the changes in half-value breadth and peak intensity of diffraction X-ray, it was supposed that a peculiar microscopic strain exists in explosion hardened steel. (author)

  15. The Co-Development of Parenting Stress and Childhood Internalizing and Externalizing Problems

    OpenAIRE

    Stone, Lisanne L.; Mares, Suzanne H. W.; Otten, Roy; Engels, Rutger C. M. E.; Janssens, Jan M. A. M.

    2015-01-01

    Although the detrimental influence of parenting stress on child problem behavior is well established, it remains unknown how these constructs affect each other over time. In accordance with a transactional model, this study investigates how the development of internalizing and externalizing problems is related to the development of parenting stress in children aged 4-9. Mothers of 1582 children participated in three one-year interval data waves. Internalizing and externalizing problems as wel...

  16. Application of x-ray method for measuring internal stress in the gear teeth surface layer

    International Nuclear Information System (INIS)

    Zaborowski, T.

    1996-01-01

    This paper presents the methodics of the internal stress measurements concerning cylindrical gear teeth of involute profile. There are the method selected, relation between stress and strain presented and conditions of investigation discussed in the study, including preparation of samples for investigation and conditions of the strain measurement. Exemplifying results of stress measurements for teeth of gears made of 4OH steel are shown. Suitability of the developed investigation method is indicated

  17. Acculturative Stress, Parental and Professor Attachment, and College Adjustment in Asian International Students

    Science.gov (United States)

    Han, Suejung; Pistole, M. Carole; Caldwell, Jarred M.

    2017-01-01

    This study examined parental and professor attachment as buffers against acculturative stress and as predictors of college adjustment of 210 Asian international students (AISs). Moderated hierarchical regression analyses revealed that acculturative stress negatively and secure parental and professor attachment positively predicted academic…

  18. Multi-Dimensionality of Acculturative Stress among Chinese International Students: What Lies behind Their Struggles?

    Science.gov (United States)

    Zhang, Yue; Jung, Eunjoo

    2017-01-01

    This study aimed to identify the underlying dimensions of acculturative stress that Chinese international students may encounter in the U.S. In addition, we re-examined students' background characteristics and perceived social support from family, friends, and their school as predictors of students' different dimensions of acculturative stress. In…

  19. Stress and Damage in Polymer Matrix Composite Materials Due to Material Degradation at High Temperatures

    Science.gov (United States)

    McManus, Hugh L.; Chamis, Christos C.

    1996-01-01

    This report describes analytical methods for calculating stresses and damage caused by degradation of the matrix constituent in polymer matrix composite materials. Laminate geometry, material properties, and matrix degradation states are specified as functions of position and time. Matrix shrinkage and property changes are modeled as functions of the degradation states. The model is incorporated into an existing composite mechanics computer code. Stresses, strains, and deformations at the laminate, ply, and micro levels are calculated, and from these calculations it is determined if there is failure of any kind. The rationale for the model (based on published experimental work) is presented, its integration into the laminate analysis code is outlined, and example results are given, with comparisons to existing material and structural data. The mechanisms behind the changes in properties and in surface cracking during long-term aging of polyimide matrix composites are clarified. High-temperature-material test methods are also evaluated.

  20. Inhomogeneous Relaxation of a Molecular Layer on an Insulator due to Compressive Stress

    Science.gov (United States)

    Bocquet, F.; Nony, L.; Mannsfeld, S. C. B.; Oison, V.; Pawlak, R.; Porte, L.; Loppacher, Ch.

    2012-05-01

    We discuss the inhomogeneous stress relaxation of a monolayer of hexahydroxytriphenylene (HHTP) which adopts the rare line-on-line (LOL) coincidence on KCl(001) and forms moiré patterns. The fact that the hexagonal HHTP layer is uniaxially compressed along the LOL makes this system an ideal candidate to discuss the influence of inhomogeneous stress relaxation. Our work is a combination of noncontact atomic force microscopy experiments, density functional theory and potential energy calculations, and a thorough interpretation by means of the Frenkel-Kontorova model. We show that the assumption of a homogeneous molecular layer is not valid for this organic-inorganic heteroepitaxial system since the best calculated energy configuration correlates with the experimental data only if inhomogeneous relaxations of the layer are taken into account.

  1. Morphological Changes of Yeast Cells due to Oxidative Stress by Mercury and Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Su Hyoun; Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    The yeast Saccharomyces cerevisiae is one of the most important microorganisms employed in industry. Growth rate, mutation, and environmental conditions affect yeast size and shape distributions but, in general, the influence of spatial variations in large-scale bioreactors is not considered. Ionizing radiation induces DNA double strand breaks in the nucleus, In addition, it causes lipid peroxidation, ceramide generation, and protein oxidation in the membrane, cytoplasm, and nucleus. Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. As a metal ion, it induces an oxidative stress or predisposes cells to an oxidative stress, with considerable damage to proteins, lipids and DNA. In this work, we investigated to effect of ionizing radiation (IR) and mercury chloride (II) on cell morphology.

  2. Service Life Of Main Piping Component Due To Low Thermal Stresses.Fatigue

    International Nuclear Information System (INIS)

    Miroshnik, R.; Jeager, A.; Ben Haim, H.

    1998-01-01

    The paper deals with estimating the service life of the power station Main piping component and describing the repair process for extending of its service life. After a long period of service, several circular fatigue cracks have been discovered at the bottom of the Main piping component chamber. Finite element analyses of transient thermal stresses, caused by power station startup, are carried out in the paper. The calculation results show good agreement between the theoretical locations of the maximum stresses and the actual locations of the cracks. There is a good agreement between theoretical evaluation and actual service life, as well. The possibility of machining out the cracks in order to prevent their growing is examined here. The machining enables us to extend the power station component's life service

  3. Storage of spent fuels: implementation of a research program on the risk of waste container rupture due to stress corrosion induced by fission products

    International Nuclear Information System (INIS)

    Parise, M.; Walle, E.; Foct, J.

    2001-01-01

    The following topics were dealt with: research programm on stress corrosion of spent fuel casks materials due to fission products, such as iodine, chemical interactions with zirconium, chemical aspects of stress corrosion, rupture risk assessment

  4. Ferroelectric behavior of a lead titanate nanosphere due to depolarization fields and mechanical stresses

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Landeta, J.; Lascano, I.

    2017-07-01

    A theorical model has been developed based on the theory of Ginzburg-Landau-Devonshire to study and predict the effects the decreasing of size particle in a nanosphere of PbTiO3 subjected to the action of depolarization fields and mechanical stress. It was considered that the nanosphere is surrounded by a layer of space charges on its surface, and containing 180° domains generated by minimizing free energy of depolarization. Energy density of depolarization, wall domain and electro-elastic energy have been incorporated into the free energy of the theory Ginzburg-Landau-Devonshire. Free energy minimization was performed to determine the spontaneous polarization and transition temperature system. These results show that the transition temperature for nanosphere is substantially smaller than the corresponding bulk material. Also, it has been obtained that the stability of the ferroelectric phase of nanosphere is favored for configurations with a large number of 180° domains, with the decreasing of thickness space charge layer, and the application of tensile stress and decreases with compressive stress. (Author)

  5. Update in the methodology of the chronic stress paradigm: internal control matters

    Directory of Open Access Journals (Sweden)

    Boyks Marco

    2011-04-01

    Full Text Available Abstract To date, the reliability of induction of a depressive-like state using chronic stress models is confronted by many methodological limitations. We believe that the modifications to the stress paradigm in mice proposed herein allow some of these limitations to be overcome. Here, we discuss a variant of the standard stress paradigm, which results in anhedonia. This anhedonic state was defined by a decrease in sucrose preference that was not exhibited by all animals. As such, we propose the use of non-anhedonic, stressed mice as an internal control in experimental mouse models of depression. The application of an internal control for the effects of stress, along with optimized behavioural testing, can enable the analysis of biological correlates of stress-induced anhedonia versus the consequences of stress alone in a chronic-stress depression model. This is illustrated, for instance, by distinct physiological and molecular profiles in anhedonic and non-anhedonic groups subjected to stress. These results argue for the use of a subgroup of individuals who are negative for the induction of a depressive phenotype during experimental paradigms of depression as an internal control, for more refined modeling of this disorder in animals.

  6. Update in the methodology of the chronic stress paradigm: internal control matters.

    Science.gov (United States)

    Strekalova, Tatyana; Couch, Yvonne; Kholod, Natalia; Boyks, Marco; Malin, Dmitry; Leprince, Pierre; Steinbusch, Harry Mw

    2011-04-27

    To date, the reliability of induction of a depressive-like state using chronic stress models is confronted by many methodological limitations. We believe that the modifications to the stress paradigm in mice proposed herein allow some of these limitations to be overcome. Here, we discuss a variant of the standard stress paradigm, which results in anhedonia. This anhedonic state was defined by a decrease in sucrose preference that was not exhibited by all animals. As such, we propose the use of non-anhedonic, stressed mice as an internal control in experimental mouse models of depression. The application of an internal control for the effects of stress, along with optimized behavioural testing, can enable the analysis of biological correlates of stress-induced anhedonia versus the consequences of stress alone in a chronic-stress depression model. This is illustrated, for instance, by distinct physiological and molecular profiles in anhedonic and non-anhedonic groups subjected to stress. These results argue for the use of a subgroup of individuals who are negative for the induction of a depressive phenotype during experimental paradigms of depression as an internal control, for more refined modeling of this disorder in animals.

  7. A database to evaluate stress intensity factors of elbows with throughwall flaws under combined internal pressure and bending moment

    International Nuclear Information System (INIS)

    Chattopadhyay, J.; Dutta, B.K.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1993-01-01

    The advent of Leak-Before-Break (LBB) concept has replaced the traditional design basis event of Double Ended Guillotine Break (DEGB) in the design of primary heat transport (PHT) piping. The use of LBB concept requires postulation of largest credible cracks at highly stressed locations and demonstration of its stability under the maximum credible loading conditions. Stress analysis of PHT piping in nuclear power plants shows that the highly stressed piping components are normally elbows and branch tees. This necessitates detailed fracture mechanics evaluation of piping connections by computing Stress Intensity Factor (SIF) and/or J-integral. Simple analytical solutions for evaluation of SIF and J-integral for cracks in straight pipes are readily available in literature. However, the same type of solutions for elbows and tees are limited in open literature. In the present work, a database is generated to evaluate SIF for throughwall circumferential and longitudinal cracks under combined internal pressure and bending moment. Different parameters to characterise a cracked elbow are pipe factor (h), pipe bore radius to thickness ratio (r/t) and crack length. Another parameter (σ) is used to consider the relative magnitude of stresses due to internal pressure and remote bending moment. The database has been used to derive closed form expressions to evaluate SIF for elbow with cracks in terms of the aforementioned parameters. (author). 8 refs., 12 figs., 3 tabs

  8. Internal stresses in steel plate generated by shape memory alloy inserts

    International Nuclear Information System (INIS)

    Malard, B.; Pilch, J.; Sittner, P.; Davydov, V.; Sedlák, P.; Konstantinidis, K.; Hughes, D.J.

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Thermoresponsive internal stresses introduced into steel by embedding SMA inclusions. ► Neutron strain scanning on steel plate coupons with NiTi inserts at 21 °C and 130 °C. ► Internal stress field in steel evaluated directly from strains and by FE simulation. ► Internal stress generation by SMA insert resistant to thermal and mechanical fatigue. - Abstract: Neutron strain scanning was employed to investigate the internal stress fields in steel plate coupons with embedded prestrained superelastic NiTi shape memory alloy inserts. Strain fields in steel were evaluated at T = 21 °C and 130 °C on virgin coupons as well as on mechanically and thermally fatigued coupons. Internal stress fields were evaluated by direct calculation of principal stress components from the experimentally measured lattice strains as well as by employing an inverse finite element modeling approach. It is shown that if the NiTi inserts are embedded into the elastic steel matrix following a carefully designed technological procedure, the internal stress fields vary with temperature in a reproducible and predictable way. It is estimated that this mechanism of internal stress generation can be safely applied in the temperature range from −20 °C to 150 °C and is relatively resistant to thermal and mechanical fatigue. The predictability and fatigue endurance of the mechanism are of essential importance for the development of future smart metal matrix composites or smart structures with embedded shape memory alloy components.

  9. Modelling loading and break-up of RC structure due to internal explosion of fragmenting shells

    NARCIS (Netherlands)

    Weerheijm, J.; Stolz, A.; Riedel, W.; Mediavilla Varas, J.

    2012-01-01

    The Klotz Group (KG), an international group of experts on explosion safety, investigates the debris throw hazard associated with the accidental detonation of ammunition in reinforced concrete (RC-) structures. Experiments are combined with engineering models but also with results of advanced

  10. Absence of internal tidal beams due to non-uniform stratification

    NARCIS (Netherlands)

    Gerkema, T.; van Haren, H.

    2012-01-01

    A linear internal-tide generation model is applied to the Faeroe–Shetland Channel, using observed profiles of stratification. Several degrees of simplification are considered: 1) uniform, i.e. constant N; 2) vertically varying N (z); 3) the full N(x, z) and associated geostrophic background flows.

  11. ELASTIC-PLASTIC AND RESIDUAL STRESS ANALYSIS OF AN ALUMINUM DISC UNDER INTERNAL PRESSURES

    Directory of Open Access Journals (Sweden)

    Numan Behlül BEKTAŞ

    2004-02-01

    Full Text Available This paper deals with elastic-plastic stress analysis of a thin aluminum disc under internal pressures. An analytical solution is performed for satisfying elastic-plastic stress-strain relations and boundary conditions for small plastic deformations. The Von-Mises Criterion is used as a yield criterion, and elastic perfectly plastic material is assumed. Elastic-plastic and residual stress distributions are obtained from inner radius to outer radius, and they are presented in tables and figures. All radial stress components, ?r, are compressive, and they are highest at the inner radius. All tangential stress components, ??, are tensile, and they are highest where the plastic deformation begins. Magnitude of the tangential residual stresses is higher than those the radial residual stresses.

  12. Simulation of inter- and transgranular crack propagation in polycrystalline aggregates due to stress corrosion cracking

    International Nuclear Information System (INIS)

    Musienko, Andrey; Cailletaud, Georges

    2009-01-01

    The motivation of the study is the development of a coupled approach able to account for the interaction between environment and plasticity in a polycrystalline material. The paper recalls first the constitutive equations used to describe the behavior of the grain core and of the grain boundary (GB). The procedure that is applied to generate synthetic polycrystalline aggregates with an explicit representation of the grain boundary area by 2D or 3D finite elements is then described. The approach is applied to the modeling of iodine-assisted stress corrosion cracking (IASCC) in Zircaloy tubes used in nuclear power plants.

  13. Advanced LMFBR fuel cladding susceptability to stress corrosion due to reprocessing impurities

    International Nuclear Information System (INIS)

    Henslee, S.P.

    1987-03-01

    The potential degradation of LMFBR fuel cladding alloys by chlorides, when used in metallic fuel systems, was evaluated. The alloys tested were D-9 and HT-9 stainless steels, austenitic and ferritic alloys respectively. These two alloys were tested in parallel with and their performance compared to the austenitic stainless steel Type 316. All alloys were tested for 7400 hours in a stress rupture environment with chloride exposure at either 550/degree/C 650/degree/C. None of the alloys tested were found to exhibit any degradation in time-to-rupture by the presence of chlorides under the conditions imposed during testing. 8 refs., 4 figs., 2 tabs

  14. «We were shocked»: Soviet captivity and internment as acculturation stress

    Directory of Open Access Journals (Sweden)

    Наталья Викторовна Суржикова

    2009-09-01

    Full Text Available N.V. Surzhikova's article based at the specific source type - memories - covers social and cultural issues of the Soviet captivity and internment. The author analyses manifestation of cultural shock or a stress of acculturation that proceeded from the direct contact of the prisoners and interned persons with another cultural conditions as well as mechanisms and limits of their adaptation.

  15. Factors Related to the Acculturation Stress of International Students in a Faith-Based Institution

    Science.gov (United States)

    de Souza, Liane Videres

    2012-01-01

    The number of international students attending American educational institutions is increasing annually. Based upon Maslow theory of needs, it was hypothesized that the acculturation process contributes to stress and anxiety among international students; therefore, it is important to understand some of the variables that influence this process for…

  16. Impact of Social Support and Coping on Acculturation and Acculturative Stress of East Asian International Students

    Science.gov (United States)

    Ra, Young-An; Trusty, Jerry

    2017-01-01

    The purpose of this study was to investigate the effects of social support and coping on acculturation and acculturative stress of international students. The authors used hierarchical multiple regression analysis to study a sample of 232 East Asian international students. The results indicate that social support and coping were partial mediators…

  17. The Interplay of International Students' Acculturative Stress, Social Support, and Acculturation Modes

    Science.gov (United States)

    Sullivan, Christopher; Kashubeck-West, Susan

    2015-01-01

    This study examined the relationship between acculturation modes (assimilation, integration, separation and marginalization), social support, and acculturative stress in undergraduate and graduate international students (N=104) at a medium-sized public university in the Midwestern United States. The study found that international students with…

  18. The Relationship Between Second Language Anxiety and International Nursing Students Stress

    Science.gov (United States)

    Khawaja, Nigar G.; Chan, Sabrina; Stein, Georgia

    2017-01-01

    We examined the relationship between second language anxiety and international nursing student stress after taking into account the demographic, cognitive, and acculturative factors. International nursing students (N = 152) completed an online questionnaire battery. Hierarchical regression analysis revealed that spoken second language anxiety and…

  19. Laser-induced cracks in ice due to temperature gradient and thermal stress

    Science.gov (United States)

    Yang, Song; Yang, Ying-Ying; Zhang, Jing-Yuan; Zhang, Zhi-Yan; Zhang, Ling; Lin, Xue-Chun

    2018-06-01

    This work presents the experimental and theoretical investigations on the mechanism of laser-induce cracks in ice. The laser-induced thermal gradient would generate significant thermal stress and lead to the cracking without thermal melting in the ice. The crack density induced by a pulsed laser in the ice critically depends on the laser scanning speed and the size of the laser spot on the surface, which determines the laser power density on the surface. A maximum of 16 cracks within an area of 17 cm × 10 cm can be generated when the laser scanning speed is at 10 mm/s and the focal point of the laser is right on the surface of the ice with a laser intensity of ∼4.6 × 107 W/cm2. By comparing the infrared images of the ice generated at various experimental conditions, it was found that a larger temperature gradient would result in more laser-induced cracks, while there is no visible melting of the ice by the laser beam. The data confirm that the laser-induced thermal stress is the main cause of the cracks created in the ice.

  20. Intragenic origins due to short G1 phases underlie oncogene-induced DNA replication stress.

    Science.gov (United States)

    Macheret, Morgane; Halazonetis, Thanos D

    2018-03-01

    Oncogene-induced DNA replication stress contributes critically to the genomic instability that is present in cancer. However, elucidating how oncogenes deregulate DNA replication has been impeded by difficulty in mapping replication initiation sites on the human genome. Here, using a sensitive assay to monitor nascent DNA synthesis in early S phase, we identified thousands of replication initiation sites in cells before and after induction of the oncogenes CCNE1 and MYC. Remarkably, both oncogenes induced firing of a novel set of DNA replication origins that mapped within highly transcribed genes. These ectopic origins were normally suppressed by transcription during G1, but precocious entry into S phase, before all genic regions had been transcribed, allowed firing of origins within genes in cells with activated oncogenes. Forks from oncogene-induced origins were prone to collapse, as a result of conflicts between replication and transcription, and were associated with DNA double-stranded break formation and chromosomal rearrangement breakpoints both in our experimental system and in a large cohort of human cancers. Thus, firing of intragenic origins caused by premature S phase entry represents a mechanism of oncogene-induced DNA replication stress that is relevant for genomic instability in human cancer.

  1. Thermoelastic stress due to an instantaneous finite line heat source in an infinite medium

    International Nuclear Information System (INIS)

    Claesson, J.; Hellstroem, G.

    1995-09-01

    The problem originates from studies of nuclear waste repositories in rock. The problem is by superposition reduced to the case of a single, infinite, antisymmetric, instantaneous line heat source. The dimensionless problem turns out to depend on the dimensionless radial and axial coordinates only, although the original time-dependent problem contains several parameters. An exact analytical solution is derived. The solution is surprisingly handy, considering the complexity of the original problem. The stress and strain field are readily obtained from derivatives of the displacement components. These fields are studied and presented in detail. Asymptotic behaviour, field of principal stresses, regions of compression and tension, and largest values of compression and tension of the components are given as exact formulas. The solution may be used to test numerical models for coupled thermoelastic processes. It may also be used in more detailed numerical simulations of the process near the heat sources as boundary conditions to account for the three-dimensional global process. 7 refs

  2. Cholesterol-producing transgenic Caenorhabditis elegans lives longer due to newly acquired enhanced stress resistance

    International Nuclear Information System (INIS)

    Lee, Eun-Young; Shim, Yhong-Hee; Chitwood, David J.; Hwang, Soon Baek; Lee, Junho; Paik, Young-Ki

    2005-01-01

    Because Caenorhabditis elegans lacks several components of the de novo sterol biosynthetic pathway, it requires sterol as an essential nutrient. Supplemented cholesterol undergoes extensive enzymatic modification in C. elegans to form other sterols of unknown function. 7-Dehydrocholesterol reductase (DHCR) catalyzes the reduction of the Δ 7 double bond of sterols and is suspected to be defective in C. elegans, in which the major endogenous sterol is 7-dehydrocholesterol (7DHC). We microinjected a human DHCR expression vector into C. elegans, which was then incorporated into chromosome by γ-radiation. This transgenic C. elegans was named cholegans, i.e., cholesterol-producing C. elegans, because it was able to convert 7DHC into cholesterol. We investigated the effects of changes in sterol composition on longevity and stress resistance by examining brood size, mean life span, UV resistance, and thermotolerance. Cholegans contained 80% more cholesterol than the wild-type control. The brood size of cholegans was reduced by 40% compared to the wild-type control, although the growth rate was not significantly changed. The mean life span of cholegans was increased up to 131% in sterol-deficient medium as compared to wild-type. The biochemical basis for life span extension of cholegans appears to partly result from its acquired resistance against both UV irradiation and thermal stress

  3. Life prediction of steam generator tubing due to stress corrosion crack using Monte Carlo Simulation

    International Nuclear Information System (INIS)

    Hu Jun; Liu Fei; Cheng Guangxu; Zhang Zaoxiao

    2011-01-01

    Highlights: → A life prediction model for SG tubing was proposed. → The initial crack length for SCC was determined. → Two failure modes called rupture mode and leak mode were considered. → A probabilistic life prediction code based on Monte Carlo method was developed. - Abstract: The failure of steam generator tubing is one of the main accidents that seriously affects the availability and safety of a nuclear power plant. In order to estimate the probability of the failure, a probabilistic model was established to predict the whole life-span and residual life of steam generator (SG) tubing. The failure investigated was stress corrosion cracking (SCC) after the generation of one through-wall axial crack. Two failure modes called rupture mode and leak mode based on probabilistic fracture mechanics were considered in this proposed model. It took into account the variance in tube geometry and material properties, and the variance in residual stresses and operating conditions, all of which govern the propagations of cracks. The proposed model was numerically calculated by using Monte Carlo Simulation (MCS). The plugging criteria were first verified and then the whole life-span and residual life of the SG tubing were obtained. Finally, important sensitivity analysis was also carried out to identify the most important parameters affecting the life of SG tubing. The results will be useful in developing optimum strategies for life-cycle management of the feedwater system in nuclear power plants.

  4. Acoustic multipath arrivals in the horizontal plane due to approaching nonlinear internal waves.

    Science.gov (United States)

    Badiey, Mohsen; Katsnelson, Boris G; Lin, Ying-Tsong; Lynch, James F

    2011-04-01

    Simultaneous measurements of acoustic wave transmissions and a nonlinear internal wave packet approaching an along-shelf acoustic path during the Shallow Water 2006 experiment are reported. The incoming internal wave packet acts as a moving frontal layer reflecting (or refracting) sound in the horizontal plane. Received acoustic signals are filtered into acoustic normal mode arrivals. It is shown that a horizontal multipath interference is produced. This has previously been called a horizontal Lloyd's mirror. The interference between the direct path and the refracted path depends on the mode number and frequency of the acoustic signal. A mechanism for the multipath interference is shown. Preliminary modeling results of this dynamic interaction using vertical modes and horizontal parabolic equation models are in good agreement with the observed data.

  5. Internal pressure changes of liquid filled shipping casks due to thermal environment

    International Nuclear Information System (INIS)

    Jackson, J.E.

    1978-01-01

    A discussion of the significance of internal pressure calculations in liquid filled shipping casks subjected to a high temperature thermal environment is presented. Some basic thermodynamic relationships are introduced and discussed as they apply to the two-phase mixture problem encountered with liquid filled casks. A model of the liquid filled cask is developed and the assumptions and limitations of the mathematical model are discussed. A relationship is derived which can be used to determine internal cask pressures as a function of initial thermodynamic loading conditions, initial fluid volume ratio and final mixture temperature. The results for water/air filled casks are presented graphically in a parametric form. The curves presented are particularly useful for preliminary design verification purposes. A qualitative discussion of the use of the results from an error analysis aspect is presented. Some pressure calculation problems frequently seen by NRC for liquid filled cask designs are discussed

  6. Missed Total Occlusion Due to the Occipital Artery Arising from the Internal Carotid Artery

    International Nuclear Information System (INIS)

    Ustunsoz, Bahri; Gumus, Burcak; Koksal, Ali; Koroglu, Mert; Akhan, Okan

    2007-01-01

    A 56-year-old man was referred for digital subtraction angiography (DSA) with an ultrasound diagnosis of right proximal internal carotid artery (ICA) stenosis for possible carotid artery stenting. DSA revealed total occlusion of the ICA and an occipital artery arising from the stump and simulating continuation of the ICA. An ascending pharyngeal artery also arose from the same occipital artery. This case is of interest because this is a rare variation besides being a cause of misdiagnosis at carotid ultrasound

  7. Finite Element Simulation and Experimental Verification of Internal Stress of Quenched AISI 4140 Cylinders

    Science.gov (United States)

    Liu, Yu; Qin, Shengwei; Hao, Qingguo; Chen, Nailu; Zuo, Xunwei; Rong, Yonghua

    2017-03-01

    The study of internal stress in quenched AISI 4140 medium carbon steel is of importance in engineering. In this work, the finite element simulation (FES) was employed to predict the distribution of internal stress in quenched AISI 4140 cylinders with two sizes of diameter based on exponent-modified (Ex-Modified) normalized function. The results indicate that the FES based on Ex-Modified normalized function proposed is better consistent with X-ray diffraction measurements of the stress distribution than FES based on normalized function proposed by Abrassart, Desalos and Leblond, respectively, which is attributed that Ex-Modified normalized function better describes transformation plasticity. Effect of temperature distribution on the phase formation, the origin of residual stress distribution and effect of transformation plasticity function on the residual stress distribution were further discussed.

  8. Ratios between effective doses for tomographic and mathematician models due to internal exposure of photons

    International Nuclear Information System (INIS)

    Lima, F.R.A.; Kramer, R.; Khoury, H.J.; Santos, A.M.; Loureiro, E.C.M.

    2005-01-01

    The development of new and sophisticated Monte Carlo codes and tomographic human phantoms or voxels motivated the International Commission on Radiological Protection (ICRP) to revise the traditional models of exposure, which have been used to calculate effective dose coefficients for organs and tissues based on mathematician phantoms known as MIRD5. This paper shows the results of calculations using tomographic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel), recently developed by the authors as well as with the phantoms ADAM and EVA, of specific genres, type MIRD5, coupled to the EGS4 Monte Carlo and MCNP4C codes, for internal exposure with photons of energies between 10 keV and 4 MeV to several organs sources. Effective Doses for both models, tomographic and mathematician, will be compared separately as a function of the Monte Carlo code replacement, of compositions of human tissues and the anatomy reproduced through tomographs. The results indicate that for photon internal exposure, the use of models of exposure based in voxel, increases the values of effective doses up to 70% for some organs sources considered in this study, when compared with the corresponding results obtained with phantoms of MIRD-5 type

  9. Settlement behavior of municipal solid waste due to internal and external environmental factors in a lysimeter.

    Science.gov (United States)

    Melo, Márcio C; Caribé, Rômulo M; Ribeiro, Libânia S; Sousa, Raul B A; Monteiro, Veruschka E D; de Paiva, William

    2016-12-05

    Long-term settlement magnitude is influenced by changes in external and internal factors that control the microbiological activity in the landfill waste body. To improve the understanding of settlement phenomena, it is instructive to study lysimeters filled with MSW. This paper aims to understand the settlement behavior of MSW by correlating internal and external factors that influence waste biodegradation in a lysimeter. Thus, a lysimeter was built, instrumented and filled with MSW from the city of Campina Grande, the state of Paraíba, Brazil. Physicochemical analysis of the waste (from three levels of depth of the lysimeter) was carried out along with MSW settlement measurements. Statistical tools such as descriptive analysis and principal component analysis (PCA) were also performed. The settlement/compression, coefficient of variation and PCA results indicated the most intense rate of biodegradation in the top layer. The PCA results of intermediate and bottom levels presented fewer physicochemical and meteorological variables correlated with compression data in contrast with the top layer. It is possible to conclude that environmental conditions may influence internal indicators of MSW biodegradation, such as the settlement.

  10. Photoelastic Studies of Internal Stress Distributions of Unidirectional Composites.

    Science.gov (United States)

    1980-12-01

    34 verre a, If t nece, e.ry and Identify by block number) ..... ’Io-dimensional phutoelastli, models were used to determine internal taading-. and...Secretary of Defense for Research and Engineering, le Pe, ,tagon,, Uashington, D.C. 10301 ]2 Commandr, T)efens. lecn, ical Information Center, Cameron

  11. Days out of role due to mental and physical illness in the South African stress and health study.

    Science.gov (United States)

    Mall, Sumaya; Lund, Crick; Vilagut, Gemma; Alonso, Jordi; Williams, David R; Stein, Dan J

    2015-03-01

    Both mental and physical disorders can result in role limitation, such as 'days out of role', which have an important impact on national productivity losses. This paper analyses data from the South African Stress and Health Study (SASH) on the association of both mental and physical disorders with days out of role. Face-to-face interviews were conducted with a representative sample of 4,351 adult South Africans. The World Health Organization's Composite International Diagnostic Interview (WHO-CIDI) was used to assess the presence of 21 mental and physical disorders that were grouped into 10 disorder categories for the analysis: major depressive disorder, any anxiety disorders, any substance abuse disorders, headaches or migraine, arthritis, chronic pain, cardiovascular, respiratory, diabetes and digestive disorders. Multiple regression techniques were used to explore associations between individual disorders, comorbid conditions, and annual days spent out of role. The estimated societal effects of the disorders [population attributable risk proportion (PARP)] were obtained. The majority of respondents who reported a mental or physical disorder also reported another disorder (62.98 %). The average number of disorders reported by respondents who had at least one disorder was 2.3. Overall 12.4 % of respondents reported any days out of role due to mental or physical disorder. Anxiety disorders and depression were associated with highest days out of role (28.2 and 27.2, respectively) followed closely by arthritis and pain (24.7 and 21.7, respectively). Any mental disorder was associated with 23.6 days out of role, while any physical disorder was associated with 15.5 days out of role. Of the mental disorders, anxiety disorders had the highest PARP in relation to days out of role (9.0 %) followed by depression (4.8 %) and substance disorder (3.3. %). More than one-third (37.6 %) of days out of role are attributable to physical disorders and 16.1 % to mental

  12. Fractures in high-strength bolts due to hydrogen induced stress corrosion. Causes and corrective actions

    International Nuclear Information System (INIS)

    Hoche, Holger; Oechsner, Matthias

    2017-01-01

    Delayed brittle fractures of high-strength bolts of the strength class 10.9 are presented, taking the example of three damage cases. The respective damage mechanisms could be attributed to hydrogen induced stress corrosion which was caused, in turn, by hydrogen absorption during operation. The examples were chosen with a particular focus on the material condition's susceptibility which explains the cause for the occurrence of the damage mechanism. However, in only one of the three cases the susceptibility was evident and could be explained by violations of normative specifications and an unfavorable material choice. Whereas in the two other examples, only slight or no deviations from the standards and/or regulations could be found. The influencing parameters that caused the damage, those that further promoted the damage, as well as possible corrective actions are discussed taking into account the three exemplary damage cases.

  13. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    DEFF Research Database (Denmark)

    Chen, Jun; Shen, Jing; Solem, Christian

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed...... riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced into L. lactis and revealed a more oxidized cytoplasm at 37°C than at 30°C....... These results indicate that L. lactis suffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller...

  14. Estimation of internal exposure dose due to Fukushima Daiichi nuclear power plant accidents

    International Nuclear Information System (INIS)

    Morita, Naoko; Takamura, Noboru; Kudo, Takashi; Yamashita, Shunichi; Miura, Miwa; Yoshida, Masahiro; Matsuda, Naoki; Ohtsuru, Akira

    2012-01-01

    Detailed analysis of internal exposure dose in 173 people sent for dealing with the Accident and stayed nearby during the period Mar 11-Apr 10, 2011, was reported. They were 156 men and 17 women, 42.2 years old in average and stayed for average 4.8 days. Analysis was done for following 4 groups of people: in group 1, 45 people had stayed during the period of Mar 11-18 for average 4.3 days; group 2, 66 people during Mar 14-22 for 2.0 days; group 3, 31 people during Mar 28-31 for 5.8 days; and group 4, 31 people during Mar 22-Apr 10 for 10.6 days. Internal radioactivity was measured for 20 min in the whole body counter placed in a low-background, iron-surrounded room in Nagasaki University. The detector was a pair of NaI (Tl) scintillator of 8 in. (diameter) x 4 in. (thickness) equipped at upper and lower portions. Nuclides measured were I-131 (at 0.364 MeV and others), Cs-134 (0.605, 0.796 MeV), Cs-137 (0.662 MeV), of which lowest detection limits were 68 Bq for I, and 28 Bq for Cs. Overall average detection rates of the respective nuclide above were found to be 31.8% (55/173 people), 37.6% (65) and 32.4% (56). In group 1, >800 Bq of the nuclides were found in the body, but in later groups, radioactivity was lower. Detection rate and internal radioactivity were thus found to be highest in those stayed immediately after the Accident. (T.T.)

  15. Estimation of inelastic behavior for a tapered nozzle in vessel due to thermal transient load using stress redistribution locus method

    International Nuclear Information System (INIS)

    Kobayashi, Ken-ichi; Yamada, Jun-ichi

    2010-01-01

    Simplified inelastic design procedures for elevated temperature components have been required to reduce simulation cost and to shorten a period of time for developing new projects. Stress redistribution locus (SRL) method has been proposed to provide a reasonable estimate employing both the elastic FEM analysis and a unique hyperbolic curve: ε tilde={1/σ tilde + (κ - 1)σ tilde}/κ, where ε tilde and σ tilde show dimensionless strain and stress normalized by corresponding elastic ones, respectively. This method is based on a fact that stress distribution in well deformed or high temperature components would change with deformation or time, and that the relation between the dimensionless stress and strain traces a kind of the elastic follow-up locus in spite of the constitutive equation of material and loading modes. In this paper, FEM analyses incorporating plasticity and creep in were performed for a tapered nozzle in reactor vessel under some thermal transient loads through the nozzle thickness. The normalized stress and strain was compared with the proposed SRL curve. Calculation results revealed that a critical point in the tapered nozzle due to the thermal transient load depended on a descending rate of temperature from the higher temperature in the operation cycle. Since the inelastic behavior in the nozzle resulted in a restricted area, the relationship between the normalized stress and strain was depicted inside the proposed SRL curve: Coefficient κ of the SRL in analyses is greater than the proposed one, and the present criterion guarantees robust structures for complicated components involving inelastic deformation. (author)

  16. Synchronization of two Hodgkin-Huxley neurons due to internal noise

    International Nuclear Information System (INIS)

    Casado, Jose Manuel

    2003-01-01

    It is well known that a strong coupling can synchronize a population of nonlinear oscillators. This fact has deep implications for the current understanding of information processing by the brain. The focus of this Letter is on the role of conductance noise on a system of two coupled Hodgkin-Huxley neurons in the so-called excitable region, where both neurons are at rest in the absence of noise. It is shown that, in this region, conductance noise allows the neurons to achieve both frequency and phase synchronization. This suggests that internal noise could play a role in the emergence of synchronous neural activity in populations of weakly coupled neurons

  17. Welding residual stress improvement in internal components by water jet peening

    International Nuclear Information System (INIS)

    Enomoto, K.; Hirano, K.; Hayashi, M.; Hayashi, E.

    1996-01-01

    Cavitations are generated when highly pressurized water is jetted in water. Surface residual stress is improved remarkably due to the peening effect of extremely high pressure caused by the collapse of cavitation bubbles. This technique is called water jet peening (WJP). WJP is expected to be an effective maintenance technique for the prevention of stress corrosion cracking caused by residual stress in various components of power generating plants. Various kinds of specimens were water jet peened to evaluate the fundamental characteristics of WJP and to select the most appropriate conditions for the residual stress improvement. Test results showed that WJP markedly improved the tensile residual stress caused by welding and grinding to the high compressive residual stress and seems to prevent the stress corrosion cracking

  18. Methods for reducing internal collective doses due to contamination of agricultural lands

    International Nuclear Information System (INIS)

    Prister, B.S.; Novikova, N.K.; Tkachenko, N.V.; Nagovisyna, L.I.; Berezhnaya, T.I.; Semenyuk, N.D.; Rudoj, V.M.

    1990-01-01

    Radioactive contamination of agricultural lands in 30 km vicinity of Chernobyl NPP asw well as agricultural products involved in food chains is considered. Attention is paid to population collective doses due to intake of contaminated food. It is shown that target optimization of agricultural production structure in territories where food contamination does not result in increase of population dose limit lies in achievement of minimal inclusion of radionuclides in human diet

  19. Influence of ion irradiation on internal residual stress in DLC films

    Energy Technology Data Exchange (ETDEWEB)

    Karaseov, Platon A., E-mail: platon.karaseov@rphf.spbstu.r [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation); Podsvirov, Oleg A.; Karabeshkin, Konstantin V. [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation); Vinogradov, Andrei Ya. [Ioffe Physicotechnical Institute RAS, Polytechnicheskaya 26, 195252 St. Petersburg (Russian Federation); Azarov, Alexander Yu. [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation); Karasev, Nikita N. [State University of Information Technologies, Mechanics and Optics, Sablinskaya Str. 14, 197101 St. Petersburg (Russian Federation); Titov, Andrei I.; Smirnov, Alexander S. [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation)

    2010-10-01

    The dependence of internal residual stress in thin diamond-like carbon films grown on Si substrate by PECVD technique on most important growth parameters, namely RF-power, DC bias voltage and substrate temperature, is described. Results show that compressive stress reaches the highest value of 2.7 GPa at low RF-power and DC bias. Increase of substrate temperature from 250 to 350 {sup o}C leads to nonlinear increase of stress value. Inhomogeneity of residual stress along the film surface disappears when film is deposited at temperatures above 275 {sup o}C. Post-growth film irradiation by P{sup +} and In{sup +} ions cause decrease of compressive stress followed by its inversion to tensile. For all ion energy combinations used residual stress changes linearly with normalized fluence up to 0.2 DPA with slope (8.7 {+-} 1.3) GPa/DPA.

  20. Mechanical and thermal stresses in a functionally graded rotating disk with variable thickness due to radially symmetry loads

    International Nuclear Information System (INIS)

    Bayat, Mehdi; Saleem, M.; Sahari, B.B.; Hamouda, A.M.S.; Mahdi, E.

    2009-01-01

    Rotating disks have many applications in the aerospace industry such as gas turbines and gears. These disks normally work under thermo mechanical loads. Minimizing the weight of such components can help reduce the overall payload in aerospace industry. For this purpose, a rotating functionally graded (FG) disk with variable thickness under a steady temperature field is considered in this paper. Thermo elastic solutions and the weight of the disk are related to the material grading index and the geometry of the disk. It is found that a disk with parabolic or hyperbolic convergent thickness profile has smaller stresses and displacements compared to a uniform thickness disk. Maximum radial stress due to centrifugal load in the solid disk with parabolic thickness profile may not be at the center unlike uniform thickness disk. Functionally graded disk with variable thickness has smaller stresses due to thermal load compared to those with uniform thickness. It is seen that for a given value of grading index, the FG disk having concave thickness profile is the lightest in weight whereas the FG disk with uniform thickness profile is the heaviest. Also for any given thickness profile, the weight of the FG disk lies in between the weights of the all-metal and the all-ceramic disks.

  1. Quantification of nanoparticle release from polymer nanocomposite coatings due to environmental stressing.

    Science.gov (United States)

    Kim, Yeon Seok; Davis, Rick; Uddin, Nasir; Nyden, Marc; Rabb, Savelas A

    2016-01-01

    Certain engineered nanoparticles (ENP) reduce the flammability of components used in soft furnishings (mattresses and upholstered furniture). However, because of the ENP's small size and ability to interact with biological molecules, these fire retardant ENPs may pose a health and environmental risks, if they are released sometime during the life cycle of the soft furnishing. Quantifying the released amount of these ENPs under normal end-use circumstances provides a basis for assessing their potential health and environmental impact. In this article, we report on efforts to identify suitable methodologies for quantifying the release of carbon nanofibers, carbon nanotubes, and sodium montmorillonites from coatings applied to the surfaces of barrier fabric and polyurethane foam. The ENPs released in simulated chewing and mechanical stressing experiments were collected in aqueous solution and quantified using Ultraviolet-Visible and inductively coupled plasma-optical emission spectroscopy. The microstructures of the released ENPs were characterized using scanning electron microscopy. The reported methodology and results provide important milestones to estimate the impact and toxicity of the ENP release during the life cycle of the nanocomposites. To our knowledge, this is the first study of ENP release from the soft furnishing coating, something that can be important application area for fire safety.

  2. Immunoelectron microscopic studies on metallothionein induction in Nile cichlid due to heavy metal stress

    International Nuclear Information System (INIS)

    Chatterjee, S.; Singh, L.; Das, T.K.; Mukhopadhyay, S.K.

    2010-01-01

    Heavy metals are important environmental pollutants and many of them are toxic even in low concentrations. The uncontrolled input of such elements in milieu is undesirable because once accumulated, are hard to remove. The release of toxic metals in biologically available forms by human activity may damage or alter both natural and man-made ecosystems. The cellular adaptation to toxicity of metals is one of the important factors for organisms living in the stressful conditions. The major type of cellular effect at the cytoplasmic level involves binding of metals through specific metal binding proteins. One of these metalloproteins is metallothionein (MT), MT is a low-molecular-weight (6-7 kDa) cysteine rich protein ubiquitous in the animal kingdom and can bind with essential (Cu + and Zn 2+ ) and nonessential (Cd 2+ , Hg 2+ and Ag + ) metals with a high thermodynamic and low kinetic stability. Again, the induction of MT by other heavy metals such as Cr, Mn and Pb was also reported by several workers

  3. Intrapartum sacral stress fracture due to pregnancy-related osteoporosis: a case report.

    Science.gov (United States)

    Oztürk, Gülcan; Külcü, Duygu Geler; Aydoğ, Ece

    2013-01-01

    Low back pain (LBP) and hip pain frequently occur during pregnancy and postpartum period. Although pelvic and mechanic lesions of the soft tissues are most responsible for the etiology, sacral fracture is also one of the rare causes. A 32-year-old primigravid patient presented with LBP and right hip pain which started 3 days after vaginal delivery. Although direct radiographic examination was normal, magnetic resonance imaging of the sacrum revealed sacral stress fracture. Lumbar spine and femoral bone mineral density showed osteoporosis as a risk factor. There were no other risk factors such as trauma, excessive weight gain, and strenuous physical activity. It is considered that the patient had sacral fatigue and insufficiency fracture in intrapartum period. The patient's symptoms subsided in 3 months after physical therapy and rest. In conclusion, sacral fractures during pregnancy and postpartum period, especially resulting from childbirth, are very rare. To date, there are two cases in the literature. In cases who even do not have risk factors related to vaginal delivery such as high birth weight infant and the use of forceps, exc., sacral fracture should be considered in the differential diagnosis of LBP and hip pain started soon after child birth. Pregnancy-related osteoporosis may lead to fracture during vaginal delivery.

  4. [STRESS DUE TO THE WORK-LIFE CONFLICT: ADVICES FROM APPLIED RESEARCH FOR COPING IT].

    Science.gov (United States)

    Poerio, Vincenzo

    2015-01-01

    Unlike most of the work-related stress research, which emphasizes how to manage stressors and maximize the psychological well-being, the present article focuses on one particular kind of stressor: the experience of conflict or interference between demands at work and responsibilities and commitments outside of the work setting, especially in respect offamily life and one's personal life. Referred to as "work-family conflict" or (more recently) "work-life conflict", this stressor has been demonstrated in research since the 1990s to exert a considerable impact on individuals' well-being along with other areas such as family functioning and even performance on the job. In contrast to the intra-role conflict, which refers to interference between roles within a single domain (e.g., the work context), work-family (or work-life) conflict is a form of inter-role interference which occurs when there is conflict across domains. In the 1980s and 1990s, research and writing in this area focused predominantly on work versus family, but in recent years the "non-work" component has been expanded to include other aspects of people's lives. For simplicity, we will refer to the two major spheres as the "work domain" (i.e., a person's paid employment) and the "life domain" (which comprises all other dimensions of life, including family, recreation, community activities and personal life). Although this classification is not entirely appropriate, it enables differentiation between the two spheres.

  5. Path Analysis of Acculturative Stress Components and Their Relationship with Depression Among International Students in China.

    Science.gov (United States)

    Liu, Yang; Chen, Xinguang; Li, Shiyue; Yu, Bin; Wang, Yan; Yan, Hong

    2016-12-01

    Acculturative stress prevents international students from adapting to the host culture, increasing their risk for depression. International students in China are a growing and at-risk population for acculturative stress and depression. With data from the International Student Health and Behaviour Survey (Yu et al., ) in China, seven acculturative stress components were detected in a previous study (Yu et al., ), including a central component (self-confidence), three distal components (value conflict, identity threat and rejection) and three proximal components (poor cultural competence, opportunity deprivation and homesickness). The current study extended the previous study to investigate the relationship between these components and depression with data also from International Student Health and Behaviour Survey. Participants were 567 students (59% male, 40.4% African, mean age = 22.75, SD = 4.11) recruited in Wuhan, China. The sample scored high on the Acculturative Stress Scale for International Students (M = 92.81, SD = 23.93) and Center for Epidemiologic Studies Short Depression Scale (M = 0.97, SD = 0.53). Acculturative stress was positively associated with depression; the association between the three distal stress components and depression was fully mediated through self-confidence, while the three proximal components had a direct effect and a self-confidence-mediated indirect effect. These findings extended the value of the previous study, highlighted the central role of self-confidence in understanding acculturative stress and depression and provided new data supporting more effective counselling for international students in China. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Oscillation of a rigid catenary riser due to the internal two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Bordalo, Sergio N.; Morooka, Celso K.; Cavalcante, Cesar C.P. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Matt, Cyntia G.C.; Franciss, Ricardo [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2008-07-01

    Production of petroleum reservoirs from deep and ultra-deep waters is of paramount importance in Brazil, and several researches are necessary to develop appropriated equipment and risers for those operational conditions. Risers are suspended pipes used to transport the petroleum fluids between the seabed and the floating production unit. The structural flexibility of riser's lines is conferred by its length when compared with the diameter, characterizing it as a slender body. The risers are submitted to large static and dynamic loads originated from its own weight, waves, currents, platform motions and the internal flow. These loadings may threaten, by fatigue, the structural integrity of the system, compromising its useful life, and so they must be considered in the riser's project. There is a large amount of knowledge in the literature about the effects of external loadings on these systems, but the effect of the internal flow remains vastly unexplored. The variation of the flow mass and momentum inside the riser causes a dynamic loading on this system, originating an oscillatory motion. Furthermore, the gas-liquid two-phase flow may assume several flow patterns (bubble, slug, intermittent or annular), each one possessing completely different characteristics. In this work, the influence of the internal flow on the oscillatory motion (whipping motion) of catenary risers is analyzed. To provide a better understanding of this physical phenomenon, a scaled apparatus was designed and built. The material used to manufacture the riser's model was a flexible silicone tube, and air and water were used to simulate the two-phase flow. The instrumentation used to measure the fluids flow rates and the sustaining force at the top of the model was installed in the apparatus. A video acquisition system was used to determine the displacements, and frequency spectrum, of color targets positioned throughout the model, under several flow conditions. The flow patterns

  7. Development of methodologies for internal exposure assessment due to the radiopharmaceutical 18FDG

    International Nuclear Information System (INIS)

    Lacerda, Isabelle Viviane Batista de

    2013-01-01

    The production of 18 F has increased in the last decade. It is produced basically for the synthesis of 18 F- fluorodeoxyglucose ( 18 FDG), the main radiopharmaceutical used in PET (Positron Emission Tomography) scans. The growth in the frequency of these tests resulted in rise of the number of occupationally exposed individuals (OEI) to the radionuclide 18 F as 18 FDG, increasing thereby the probability of its accidental incorporation. This study aimed to implement optimized techniques for assessing internal exposures of individuals occupationally exposed through both in vivo and in vitro bioassay methods during production and handling of 18 FDG at the Divisao de Producao de Radiofarmacos (DIPRA), Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN). The in vivo monitoring was conducted at the Laboratorio de Dosimetria Interna, Divisao de Laboratorios Tecnico-Cientificos (DILAB). For this bioassay method, measurements were done with a 3x3' NaI(Tl) scintillation detector coupled to Genie 2000 software. The calibration of the system was performed with a brain phantom containing a standard liquid source of 22 Na to simulate a contaminated individual. The calibration of the HPGe coaxial detector for in vitro monitoring was performed at the Laboratorio de Medidas de Atividade de Radionuclideos (DIPRA/CRCN-NE/CNEN) with a standard source of 22 Na. Base on the calibration factors, it was possible to determine the minimum detectable activities (MDA) for the systems by using direct measurements and simulation of uncontaminated urine. Then, through the biokinetic models published by ICRP 106 and edited by the AIDE software (version 6.0), it was possible to estimate the minimum detectable effective dose (MDED), which evaluates the detection sensitivity of the techniques developed. The MDED was estimated for in vivo and in vitro measurements performed 2.4 hours after the occurrence of incorporation by ingestion, since this is the period of higher retention fraction

  8. Health risks in international container and bulk cargo transport due to volatile toxic compounds

    DEFF Research Database (Denmark)

    Baur, Xaver; Budnik, Lygia T; Zhao, Zhiwei

    2015-01-01

    To ensure the preservation and quality of the goods, physical (i.e. radiation) or chemical pest control is needed. The dark side of such consents may bear health risks in international transport and production sharing. In fact, between 10% and 20% of all containers arriving European harbors were...... with lethal outcome, occur not only during the fumigation, but also during freight transport (on bulk carriers and other transport vessels), as well as in the logistic lines during loading and unloading. Risk occupations include dock-workers, seafarers, inspectors, as well as the usually uninformed workers...... of importing enterprises that unload the products. Bystanders as well as vulnerable consumers may also be at risk. Ongoing studies focus on the release of these toxic volatile substances from various goods. It was shown that the half-lives of the off-gassing process range between minutes and months, depending...

  9. Internal Exposure of a Seoul Subway Passenger due to Radon Inhalation: Before and After PSD Installation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji-Yong; Kim, Eun-Hee [Seoul National University, Seoul (Korea, Republic of)

    2015-05-15

    Radon is the major source of public exposure to natural radiation and is also known to cause lung cancer. Platform screen doors (PSD) were installed primarily for passenger's safety purposes. Radon concentration and aerosol distribution have been changed since PSD installation. In this study, we have assessed the annual effective dose of regular subway passengers, before and after PSD installation, by employing current available data on air concentration of radon in Seoul subways with aerosol size distributions taken into account. ICRP recommends that the reference value for internal dose from radon be between 1.0 and 20.0 mSv. Korean Ministry of Environment enacted the indoor radon regulation, which requires the indoor radon level should not exceed 148 Bq/m{sup 3}. Radon concentrations in Seoul subways and annual dose estimates meet the requirements.

  10. Internal Exposure of a Seoul Subway Passenger due to Radon Inhalation: Before and After PSD Installation

    International Nuclear Information System (INIS)

    Shin, Ji-Yong; Kim, Eun-Hee

    2015-01-01

    Radon is the major source of public exposure to natural radiation and is also known to cause lung cancer. Platform screen doors (PSD) were installed primarily for passenger's safety purposes. Radon concentration and aerosol distribution have been changed since PSD installation. In this study, we have assessed the annual effective dose of regular subway passengers, before and after PSD installation, by employing current available data on air concentration of radon in Seoul subways with aerosol size distributions taken into account. ICRP recommends that the reference value for internal dose from radon be between 1.0 and 20.0 mSv. Korean Ministry of Environment enacted the indoor radon regulation, which requires the indoor radon level should not exceed 148 Bq/m 3 . Radon concentrations in Seoul subways and annual dose estimates meet the requirements

  11. Flow effects due to valve and piston motion in an internal combustion engine exhaust port

    International Nuclear Information System (INIS)

    Semlitsch, Bernhard; Wang, Yue; Mihăescu, Mihai

    2015-01-01

    Highlights: • Flow regime identification depending on the valve lift during the exhaust stroke. • Analysis of the valve motion effect onto the flow development in the exhaust port. • Physical interpretation of commonly used discharge and flow coefficient formulations. • Illustration of flow effects in junction regions with pulsatile flow. - Abstract: Performance optimization regarding e.g. exhaust valve strategies in an internal combustion engine is often performed based on one-dimensional simulation investigation. Commonly, a discharge coefficient is used to describe the flow behavior in complex geometries, such as the exhaust port. This discharge coefficient for an exhaust port is obtained by laboratory experiments at fixed valve lifts, room temperatures, and low total pressure drops. The present study investigates the consequences of the valve and piston motion onto the energy losses and the discharge coefficient. Therefore, Large Eddy Simulations are performed in a realistic internal combustion geometry using three different modeling strategies, i.e. fixed valve lift and fixed piston, moving piston and fixed valve lift, and moving piston and moving valve, to estimate the energy losses. The differences in the flow field development with the different modeling approaches is delineated and the dynamic effects onto the primary quantities, e.g. discharge coefficient, are quantified. Considering the motion of piston and valves leads to negative total pressure losses during the exhaust cycle, which cannot be observed at fixed valve lifts. Additionally, the induced flow structures develop differently when valve motion is taken into consideration, which leads to a significant disparity of mass flow rates evolving through the two individual valve ports. However, accounting for piston motion and limited valve motion, leads to a minor discharge coefficient alteration of about one to two percent

  12. Understanding Stress-Related Behavioral Phenotypes: Report from the 1st International Neuroscience Summer School and the 11th InternationalStress and Behavior” Conference

    Directory of Open Access Journals (Sweden)

    J. L. LaPorte

    2008-01-01

    Full Text Available The 1st International Neuroscience Summer School and the 11th International Multidisciplinary Neuroscience and Biopsychiatry Conference on Stress and Behavior were held in St. Petersburg, Russia, during May 9–20, 2008. The summer school gathered 30 talented young scientists from 15 countries worldwide, and was dedicated to different topics of behavioral neuroscience. Many interactive courses were provided on neuropharmacology, animal phenotyping, and biopsychology. The conference's excellent scientific and social program attracted almost 500 delegates from 40 countries from many areas of stress research. The eclectic interaction between medical doctors, basic scientists, psychologists, and students made for a productive and collaborative environment, which contributed greatly to the success of the school and conference.

  13. Flight diversions due to onboard medical emergencies on an international commercial airline.

    Science.gov (United States)

    Valani, Rahim; Cornacchia, Marisa; Kube, Douglas

    2010-11-01

    Each year, close to 2 billion passengers travel on commercial airlines. In-flight medical events result in suboptimal care due to a variety of factors. Flight diversions due to medical emergencies carry a significant financial and legal cost. The purpose of this study was to determine the causes of in-flight medical diversions from Air Canada. This was a review of in-flight medical emergencies from 2004-2008. Both telemedicine and Air Canada databases were crossreferenced to capture all incidents. Presenting complaints were categorized by systems. Descriptive statistics were used to analyze the data. Over the 5 yr, there were 220 diversions, of which 91 (41.4%) of the decisions were made by pilots or onboard medical personnel. During this period there were 5386 telemedicine contacts with ground support providers, who on average recommended 2.4 diversions per 100 calls. The rate for diversions almost doubled from 2006 to 2007, with a sharp drop in telemedicine contacts during the same period. The four most common categories resulting in diversions were cardiac (58 diversions, 26.4%), neurological (43 diversions, 19.5%), gastrointestinal (GI) (25 diversions, 11.4%), and syncope (22 diversions, 10.0%). Only 6.8% of all diversions were due to cardiac arrest. Medical conditions most commonly leading to diversions were cardiac, neurological, gastrointestinal, and syncope. Our study showed that a decrease in telemedicine contact during this period was accompanied by an increase in diversions, while increased pre-screening of passengers did not prove effective in decreasing diversion rates.

  14. Effect of constraint condition and internal medium on residual stress under overlay welding for dissimilar metal welding

    International Nuclear Information System (INIS)

    Song, Tae Kwang; Kim, Yun Jae; Lee, Kyoung Soo; Park, Chi Yong; Kim, Jong Sung; Kim, Jin Weon

    2007-01-01

    In nuclear power plants, residual stress of dissimilar metal weld propagates cracks in the weld metal which is susceptible to stress corrosion cracking. Overlay welding is a process widely used to mitigate residual stress replacing inside tensile stress by compression stress. However, according to the result of this study the effect of overlay welding on residual stress depends on both internal medium and constraint condition. The purpose of this study is to maximize the positive effect of overlay welding by finite element analyses

  15. Usefulness of dipyridamole stress myocardial imaging in patients who have exercise limitations due to various orthopedic disorders

    International Nuclear Information System (INIS)

    Tagawa, Hirofumi; Ashihara, Toshiaki; Fukuyama, Takaya; Matsui, Kanji; Yamamoto, Sumiki; Yamamoto, Susumu

    1994-01-01

    To evaluate the presence of coronary artery disease in patients unable to exercise adequately because of chronic rheumatoid arthritis, osteoarthritis, hip bone fractures or disk herniation, we performed dipyridamole-stress thallium-201 myocardial imaging in thirty-three patients. Twelve of the 33 patients showed perfusion defect and redistribution by thallium imaging. Coronary angiography was performed in 9 patients out of these 12 dipyridamole-positive patients and significant coronary artery stenosis was detected in 7 of them (78%). Due to these results of dipyridamole-imaging and coronary angiograms, surgical intervention for the underlying bone or joint disorder was performed under cardioprotective strategy in 15 patients, in which no cardiovascular events occurred. Thus, dipyridamole-stress myocardial imaging is a satisfactory alternative to the exercise test for detecting coronary artery disease in patients with bone or joint disorders. (author)

  16. On the mechanical stress of Zr, Zry, and other materials due to the formation of oxide layers

    International Nuclear Information System (INIS)

    Hofmann, P.

    1977-06-01

    Several mechanisms are indicated which during oxidation of sheets, tubes, and cylinders of pure metals and alloys might lead to plastic deformation of the remaining uncorroded cross section. Some experimental methods are described which allow evaluation of stresses occurring in oxide layers. The main reason for the creep deformation of flat and tubular specimens made of Zr and Zr alloys lies in the stresses that arise from volume increase due to the growth of oxide layers. Plastic deformations of the sheet metal specimens can be up to 100% and are anisotropic. In tubular specimens the changes in geometry (axial, radial) are much smaller in the course of oxidation and attain 2% at the maximum for Zr- or Zry-tubes and go up to 10% for Ta-tubes when no differential pressure is applied simultaneously. (orig.) [de

  17. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    Science.gov (United States)

    Chen, Jun; Shen, Jing

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed quickly. Raising the temperature to 37°C resulted in severe growth inhibition and only slow removal of dissolved oxygen. Under these conditions, an abnormally low intracellular ratio of [ATP] to [ADP] (1.4) was found (normally around 5), which indicates that the cells are energy limited. By adding riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced into L. lactis and revealed a more oxidized cytoplasm at 37°C than at 30°C. These results indicate that L. lactis suffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller. The drop was accompanied by a decrease in NADH oxidase and pyruvate dehydrogenase activities, both of which depend on FAD as a cofactor. By overexpressing the riboflavin transporter, it was possible to improve FAD biosynthesis, which resulted in increased NADH oxidase and pyruvate dehydrogenase activities and improved fitness at high temperatures in the presence of oxygen. PMID:23913422

  18. Proline accumulation in lemongrass (Cymbopogon flexuosus Stapf.) due to heavy metal stress.

    Science.gov (United States)

    Handique, G K; Handique, A K

    2009-03-01

    Toxic heavy metals viz. lead, mercury and cadmium induced differential accumulation of proline in lemongrass (Cymbopogon flexuosus Stapf.) grown in soil amended with 50, 100, 200, 350 and 500 mg kg(-1) of the metals have been studied. Proline accumulation was found to be metal specific, organ specific and linear dose dependant. Further, proline accumulation following short term exposure (two months after transplantation) was higher than long term exposure (nine months after transplantation). Proline accumulation following short term exposure was 2.032 to 3.839 micro moles g(-1) for cadmium (50-200 mg kg(-1)); the corresponding range for mercury was 1.968 to 5.670 micro moles g(-1) and 0.830 to 4.567 micro moles g(-1) for lead (50-500 mg kg(-1) for mercury and lead). Proline accumulation was consistently higher in young tender leaf than old leaf, irrespective of the metal or duration of exposure. For cadmium treatment proline level was 2.032 to 3.839 micro moles g(-1) for young leaves while the corresponding value for old leaf was 1.728 to 2.396 micro moles g(-1) following short term exposure. The same trend was observed for the other two metals and duration of exposure. For control set proline accumulation in root was 0.425 micro moles g(-1) as against 0.805 and 0.533 micro moles g(-1) in young and old leaves respectively indicating that proline accumulation in root are lower than leaves, under both normal and stressed condition.

  19. The water avoidance stress induces bladder pain due to a prolonged alpha1A adrenoceptor stimulation.

    Science.gov (United States)

    Matos, Rita; Serrão, Paula; Rodriguez, Larissa; Birder, Lori Ann; Cruz, Francisco; Charrua, Ana

    2017-08-01

    Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) remains an elusive disease with the cause for the pain unclear. BPS/IC patients present increased sympathetic activity and high levels of urinary noradrenaline. At the experimental level, it has been shown that chronic adrenergic stimulation produces pain and bladder changes through an alpha 1A adrenoceptor mediated mechanism. Water avoidance stress (WAS) in rodents reproduces signs of nociception and bladder changes seen in BPS/IC patients. In this study, we explore the possible role of alpha 1A adrenoceptor in bladder pain and morphological changes. WAS was induced in a group of female Wistar rats. A separate WAS group received 0.2 mg/kg day silodosin (WAS + S). Lower abdominal pain was determined by performing sensitivity to Von Frey filaments. Bladder reflex activity was determined by cystometry in anaesthetised animals. Urine was collected for noradrenaline quantification by HPLC. Bladders were harvested and stained with Haematoxylin-eosin (to analyse urothelial morphology and to determine the disruption of surface umbrella cells) or with Toluidine Blue 0.1% to analyse mast cell infiltration. WAS increased urinary noradrenaline level and bladder frequency and decreased mechanical pain threshold, which was reversed by silodosin. WAS induced lymphocytic and mast cells infiltration in the mucosa and mild urothelial disruption, which was absent in WAS + S group. Alpha 1A adrenoceptor stimulation has an important role in the appearance of bladder pain in rats. Since BPS/IC patients present high levels of noradrenaline, alpha 1A stimulation may be an additional trigger for bladder dysfunction presented by these patients. Further studies will determine the clinical relevance of this finding in the treatment of BPS/IC patients.

  20. Stresses and displacements in vessels due to loads imposed by single and multiple piping attachments

    International Nuclear Information System (INIS)

    Wong, F.M.G.; Craft, W.J.; East, G.H.

    1985-01-01

    The Fourier solution for thin shell equations models pressure vessels as continuous simply connected surfaces with local loads. The technique allows placement of tractions with combinations of radial, shear, and axial components. Unlike Bijlaard, the solution in this paper includes loads placed at any position along the cylinder. Stiffness and the enhanced load-carrying capacity that internal pressure gives to thin vessels can be simulated. Numerical convergence problems are reduced by an improved displacement-load algorithm, and by use of load sites that allow the circular functions to be compactly grouped. A variety of loading distributions may be analyzed including large and small nozzles near and away from centerlines. Both rectangular and circular attachments are simulated. Through superposition, multiple attachments with their own loads may be examined. The attachments to the vessel may be either rigid or soft. A comparison to analytical results from Bijlaard shows excellent agreement. Comparisons with experimental tests on an API-650 nozzle on a storage tank are in good agreement. Variations between experimental and calculated results are primarily caused by assuming a simply supported base in the calculation, whereas in the experimental test, the base is more nearly fixed

  1. Health risks in international container and bulk cargo transport due to volatile toxic compounds.

    Science.gov (United States)

    Baur, Xaver; Budnik, Lygia Therese; Zhao, Zhiwei; Bratveit, Magne; Djurhuus, Rune; Verschoor, Louis; Rubino, Federico Maria; Colosio, Claudio; Jepsen, Jorgen R

    2015-01-01

    To ensure the preservation and quality of the goods, physical (i.e. radiation) or chemical pest control is needed. The dark side of such consents may bear health risks in international transport and production sharing. In fact, between 10% and 20% of all containers arriving European harbors were shown to contain volatile toxic substances above the exposure limit values. Possible exposure to these toxic chemicals may occur not only for the applicators but also the receiver by off gassing from products, packing materials or transport units like containers. A number of intoxications, some with lethal outcome, occur not only during the fumigation, but also during freight transport (on bulk carriers and other transport vessels), as well as in the logistic lines during loading and unloading. Risk occupations include dock-workers, seafarers, inspectors, as well as the usually uninformed workers of importing enterprises that unload the products. Bystanders as well as vulnerable consumers may also be at risk. Ongoing studies focus on the release of these toxic volatile substances from various goods. It was shown that the half-lives of the off-gassing process range between minutes and months, depending on the toxic substance, its chemical reactivity, concentration, the temperature, the contaminated matrix (goods and packing materials), and the packing density in the transport units. Regulations on declaration and handling dangerous goods are mostly not followed. It is obvious that this hazardous situation in freight transport urgently requires preventive steps. In order to improve awareness and relevant knowledge there is a need for more comprehensive information on chemical hazards and a broader implementation of the already existing regulations and guidelines, such as those from ILO, IMO, and national authorities. It is also necessary to have regular controls by the authorities on a worldwide scale, which should be followed by sanctions in case of disregarding regulations

  2. Asynchronous partial contact motion due to internal resonance in multiple degree-of-freedom rotordynamics.

    Science.gov (United States)

    Shaw, A D; Champneys, A R; Friswell, M I

    2016-08-01

    Sudden onset of violent chattering or whirling rotor-stator contact motion in rotational machines can cause significant damage in many industrial applications. It is shown that internal resonance can lead to the onset of bouncing-type partial contact motion away from primary resonances. These partial contact limit cycles can involve any two modes of an arbitrarily high degree-of-freedom system, and can be seen as an extension of a synchronization condition previously reported for a single disc system. The synchronization formula predicts multiple drivespeeds, corresponding to different forms of mode-locked bouncing orbits. These results are backed up by a brute-force bifurcation analysis which reveals numerical existence of the corresponding family of bouncing orbits at supercritical drivespeeds, provided the damping is sufficiently low. The numerics reveal many overlapping families of solutions, which leads to significant multi-stability of the response at given drive speeds. Further, secondary bifurcations can also occur within each family, altering the nature of the response and ultimately leading to chaos. It is illustrated how stiffness and damping of the stator have a large effect on the number and nature of the partial contact solutions, illustrating the extreme sensitivity that would be observed in practice.

  3. Internal hernia due to adjustable gastric band tubing: review of the literature and illustrative case video.

    Science.gov (United States)

    Hamed, Osama H; Simpson, Lashondria; Lomenzo, Emanuele; Kligman, Mark D

    2013-11-01

    Laparoscopic adjustable gastric banding (LAGB) is a commonly performed bariatric procedure. Device-related morbidity is typically associated with the subcutaneous port or the band itself. Complications related to band tubing are unusual. Small bowel obstruction (SBO) after LAGB is a unique and serious complication; there is the potential of delayed diagnosis and the risk of closed-loop bowel obstruction. SBO secondary to internal hernia caused by band tubing is very rare, with only five cases reported in the literature. In this article, we describe our experience and provide an illustrative video of a case of SBO related to band tubing. We also provide a detailed review of the few previously published case reports. Based on the common features of our case and other published case reports, we hypothesize some risk factors that might lead to this unique morbidity of adjustable gastric band tubing and provide potential solutions to prevent this problem. Tubing-related SBO is a serious complication with the risk of closed-loop bowel obstruction. Urgent operative exploration is required to avoid bowel strangulation. To prevent recurrence we advise functionally shortening the tubing by tucking it to the right upper quadrant above the liver and also provide some omental coverage between the bowel and band tubing if possible.

  4. Estimating the Need for Medical Intervention due to Sleep Disruption on the International Space Station

    Science.gov (United States)

    Myers, Jerry G.; Lewandowski, Beth E.; Brooker, John E.; Hurst, S. R.; Mallis, Melissa M.; Caldwell, J. Lynn

    2008-01-01

    During ISS and shuttle missions, difficulties with sleep affect more than half of all US crews. Mitigation strategies to help astronauts cope with the challenges of disrupted sleep patterns can negatively impact both mission planning and vehicle design. The methods for addressing known detrimental impacts for some mission scenarios may have a substantial impact on vehicle specific consumable mass or volume or on the mission timeline. As part of the Integrated Medical Model (IMM) task, NASA Glenn Research Center is leading the development of a Monte Carlo based forecasting tool designed to determine the consumables required to address risks related to sleep disruption. The model currently focuses on the International Space Station and uses an algorithm that assembles representative mission schedules and feeds this into a well validated model that predicts relative levels of performance, and need for sleep (SAFTE Model, IBR Inc). Correlation of the resulting output to self-diagnosed needs for hypnotics, stimulants, and other pharmaceutical countermeasures, allows prediction of pharmaceutical use and the uncertainty of the specified prediction. This paper outlines a conceptual model for determining a rate of pharmaceutical utilization that can be used in the IMM model for comparison and optimization of mitigation methods with respect to all other significant medical needs and interventions.

  5. Determination of internal radiation dose due to intake of polonium 210 and lead 210 via smoking

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Kharita, M.H.; Nashawati, A.; Amin, Y.; Al-Akel, B.

    2004-12-01

    In this study, 18 kind of cigarettes and five kinds of molasses consumed by Syrians were collected and analyzed for radioactivity in order to estimate the internal radiation dose caused by 210 Po and 210 Pb intake. Polonium 210 and lead 210 concentrations varied between 4 and 16.4 m Bq/cigarette, while 210 Po distribution ratios in different parts of consumed cigarette were %12, %73, %1.6 in ash, smoke and filter, respectively. In addition, annual intake of 210 Po by a main smoker was varied between 4.4 and 18 Bq/year assuming that the main smoker breathes about 15% of the total 210 Po present in tobacco. Using the values of the annual intake, annual equivalent radiation dose caused by smoking has reached 178 μSv/year. Moreover, mean concentration of 210 Po in nonsmokers and smokers bloods has reached 130 and 97 mBq/l, respectively, while the mean value of 210 Po concentration was relatively higher and reached 176 and 155 mBq/l in smokers and non smoker bloods, respectively (Authors)

  6. Phase-matched light amplification by three-wave mixing process in a birefringent fiber due to externally applied stress

    International Nuclear Information System (INIS)

    Ohashi, M.; Kitayama, K.; Ishida, Y.; Uchida, N.

    1982-01-01

    A novel method to achieve phase-matched light amplification in a birefringent fiber via the three-wave mixing is proposed by using frequency shift change due to the stress applied to the fiber. It is confirmed that the signal power from a cw laser diode at lambda = 1.292 μm is amplified by 6.1 x 10 3 times in the birefringent fiber pumped with a Q-switched Nd: yttrium aluminum garnet laser at lambda = 1.064 μm. This will provide a new fiber-optic light signal amplifier having a good tolerance for variation of signal wavelengths

  7. Posttraumatic Stress Disorder After Bereavement: Early Psychological Sequelae of Losing a Close Relative Due to Terminal Cancer

    DEFF Research Database (Denmark)

    Kristensen, T. E.; Elklit, A.; Karstoft, K. I.

    2012-01-01

    Very few studies have investigated posttraumatic stress disorder (PTSD) as a consequence of bereavement from terminal illness. Therefore, knowledge on the traumatizing effects of bereavement and risk factors for traumatization from bereavement is rather sparse. This study investigated prevalence...... and predictors of PTSD in a group of people who had recently lost a close relative due to incurable cancer. The participants were 132 persons who were assessed with the Harvard Trauma Questionnaire, the Trauma Symptom Checklist, and the Crisis Support Scale. One month after the loss, 29.5% of the subjects had...

  8. Search for stress dependence in the internal friction of fused silica

    International Nuclear Information System (INIS)

    Willems, Phil; Lamb, Corinne; Heptonstall, Alastair; Hough, Jim

    2003-01-01

    The quality factor (Q) of the vertical bounce mode of a fused silica fiber pendulum is measured at high and low stresses. The internal friction of fused silica fibers is found to be independent of stress from 12.8 to 213 MPa at a level of 1.6x10 -8 . Comparison with Q's of fiber bending modes is consistent with losses concentrated in the surface of the fiber

  9. Predicting developmental changes in internalizing symptoms: examining the interplay between parenting and neuroendocrine stress reactivity.

    Science.gov (United States)

    Kuhlman, Kate R; Olson, Sheryl L; Lopez-Duran, Nestor L

    2014-07-01

    In this study, we examined whether parenting and HPA-axis reactivity during middle childhood predicted increases in internalizing symptoms during the transition to adolescence, and whether HPA-axis reactivity mediated the impact of parenting on internalizing symptoms. The study included 65 children (35 boys) who were assessed at age 5, 7, and 11. Parenting behaviors were assessed via parent report at age 5 and 11. The child's HPA-axis reactivity was measured at age 7 via a stress task. Internalizing symptoms were measured via teacher reports at age 5 and 11. High maternal warmth at age 5 predicted lower internalizing symptoms at age 11. Also, high reported maternal warmth and induction predicted lower HPA-axis reactivity. Additionally, greater HPA-axis reactivity at age 7 was associated with greater increases in internalizing symptoms from age 5 to 11. Finally, the association between age 5 maternal warmth and age 11 internalizing symptoms was partially mediated by lower cortisol in response to the stress task. Thus, parenting behaviors in early development may influence the physiological stress response system and therefore buffer the development of internalizing symptoms during preadolescence when risk for disorder onset is high. © 2013 Wiley Periodicals, Inc.

  10. Low Vagal Tone Magnifies the Association Between Psychosocial Stress Exposure and Internalizing Psychopathology in Adolescents

    Science.gov (United States)

    McLaughlin, Katie A.; Rith-Najarian, Leslie; Dirks, Melanie A.; Sheridan, Margaret A.

    2014-01-01

    Vagal tone is a measure of cardiovascular function that facilitates adaptive responses to environmental challenge. Low vagal tone is associated with poor emotional and attentional regulation in children and has been conceptualized as a marker of sensitivity to stress. We investigated whether the associations of a wide range of psychosocial stressors with internalizing and externalizing psychopathology were magnified in adolescents with low vagal tone. Resting heart period data were collected from a diverse community sample of adolescents (ages 13–17; N =168). Adolescents completed measures assessing internalizing and externalizing psychopathology and exposure to stressors occurring in family, peer, and community contexts. Respiratory sinus arrhythmia (RSA) was calculated from the interbeat interval time series. We estimated interactions between RSA and stress exposure in predicting internalizing and externalizing symptoms and evaluated whether interactions differed by gender. Exposure to psychosocial stressors was associated strongly with psychopathology. RSA was unrelated to internalizing or externalizing problems. Significant interactions were observed between RSA and child abuse, community violence, peer victimization, and traumatic events in predicting internalizing but not externalizing symptoms. Stressors were positively associated with internalizing symptoms in adolescents with low RSA but not in those with high RSA. Similar patterns were observed for anxiety and depression. These interactions were more consistently observed for male than female individuals. Low vagal tone is associated with internalizing psychopathology in adolescents exposed to high levels of stressors. Measurement of vagal tone in clinical settings might provide useful information about sensitivity to stress in child and adolescent clients. PMID:24156380

  11. Do hospital shift charge nurses from different cultures experience similar stress? An international cross sectional study.

    Science.gov (United States)

    Admi, Hanna; Eilon-Moshe, Yael

    2016-11-01

    prerequisite educational program should be mandatory for nurses prior to their nomination as shift charge nurses. Programs should be tailored to address the stress experienced by shift charge nurses. Ongoing mentorship and workshops are recommended to develop and maintain leadership abilities to cope with role stress. Future research should explore internationally the unique nature and stress of the shift charge nurse's role and replicate this study by using the Charge Nurse Stress Questionnaire in other countries. Further international comparative studies are recommended to evaluate stress perceptions of nurses in other roles and in different practice areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Burnout and stress amongst interns in Irish hospitals: contributing factors and potential solutions.

    Science.gov (United States)

    Hannan, E; Breslin, N; Doherty, E; McGreal, M; Moneley, D; Offiah, G

    2018-05-01

    The transition from medical school to internship can be daunting for newly qualified doctors. High rates of stress and burnout have been reported, with negative impacts on patient care and physician wellbeing. We surveyed interns in our hospital group to evaluate rates of stress and burnout, as well as identify the causative factors and propose potential solutions to these. A hundred and one interns working in four different hospitals over a 2-year period were invited to participate in an anonymous survey. The survey collected basic demographic details and surveyed aspects of mental health using the burnout scale, Maslach Burnout Inventory (MBI) and the stress scale and 12-item General Health Questionnaire (GHQ-12). Interns were also asked to rate a variety of workplace factors on a Likert scale based on the degree of stress caused. Finally, they were surveyed on their awareness of support services available to them. Our results showed that 37% of interns met the criteria for psychological distress, high levels of emotional exhaustion, high depersonalisation and a low sense of personal accomplishment were reported in 55.4, 51.5 and 41.6%, respectively. Inadequate preparation for practice, financial worries, poor role definition and sleep deprivation were reported as significant stressors. Most were unaware of available support services and expressed interest in leaving Ireland after internship. Burnout and stress are significant problems amongst doctors in Irish hospitals. Ensuring better preparation for clinical practice and awareness of support services is vital to tackle this issue.

  13. Experimental Study of the Effect of Internal Defects on Stress Waves during Automated Fiber Placement

    Directory of Open Access Journals (Sweden)

    Zhenyu Han

    2018-04-01

    Full Text Available The detection technique of component defects is currently only realized to detect offline defects and online surface defects during automated fiber placement (AFP. The characteristics of stress waves can be effectively applied to identify and detect internal defects in material structure. However, the correlation mechanism between stress waves and internal defects remains unclear during the AFP process. This paper proposes a novel experimental method to test stress waves, where continuous loading induced by process itself is used as an excitation source without other external excitation. Twenty-seven groups of thermosetting prepreg laminates under different processing parameters are manufactured to obtain different void content. In order to quantitatively estimate the void content in the prepreg structure, the relation model between the void content and ultrasonic attenuation coefficient is revealed using an A-scan ultrasonic flaw detector and photographic methods by optical microscope. Furthermore, the high-frequency noises of stress waves are removed using Haar wavelet transform. The peaks, the Manhattan distance and mean stress during the laying process are analyzed and evaluated. Partial conclusions in this paper could provide theoretical support for online real-time detection of internal defects based on stress wave characteristics.

  14. Stress concentration factors for an internally pressurized circular vessel containing a radial U-notch

    International Nuclear Information System (INIS)

    Carvalho, E.A. de

    2005-01-01

    This paper evaluates the stress concentration factors for an internally pressurized cylinder containing a radial U-notch along its length. This work studies the cases where the external to internal radius ratio (Ψ) is equal to 1.26, 1.52, 2.00, and 3.00 and the notch radius to internal radius ratio (Φ) is fixed and equal to 0.026. The U-notch depth varies from 0.1 to 0.6 of the wall thickness. Results are also presented for a fixed size semi-circular notch. Hoop stresses at the external wall are presented, showing regions where the stress matches the nominal one and the favourable places to install strain sensors. The finite element method is used to determine the stress concentration factors (K t ) for the above described situations and for a special case where a varying semi-circular notch is present with Ψ=3.00. This notch depth varies from 0.013 to 0.3 of the wall thickness. It is pointed out that even relatively small notches introduce large stress concentrations and disrupt the hoop stress distribution all over the cross section. Results are also compared to an example found in the literature for semi-circular notches and K t curves for both cases present the same shape

  15. Internal electron transport barrier due to neoclassical ambipolarity in the Helically Symmetric Experiment

    International Nuclear Information System (INIS)

    Lore, J.; Briesemeister, A.; Anderson, D. T.; Anderson, F. S. B.; Likin, K. M.; Talmadge, J. N.; Zhai, K.; Guttenfelder, W.; Deng, C. B.; Spong, D. A.

    2010-01-01

    Electron cyclotron heated plasmas in the Helically Symmetric Experiment (HSX) feature strongly peaked electron temperature profiles; central temperatures are 2.5 keV with 100 kW injected power. These measurements, coupled with neoclassical predictions of large 'electron root' radial electric fields with strong radial shear, are evidence of a neoclassically driven thermal transport barrier. Neoclassical transport quantities are calculated using the PENTA code [D. A. Spong, Phys. Plasmas 12, 056114 (2005)], in which momentum is conserved and parallel flow is included. Unlike a conventional stellarator, which exhibits strong flow damping in all directions on a flux surface, quasisymmetric stellarators are free to rotate in the direction of symmetry, and the effect of momentum conservation in neoclassical calculations may therefore be significant. Momentum conservation is shown to modify the neoclassical ion flux and ambipolar ion root radial electric fields in the quasisymmetric configuration. The effect is much smaller in a HSX configuration where the symmetry is spoiled. In addition to neoclassical transport, a model of trapped electron mode turbulence is used to calculate the turbulent-driven electron thermal diffusivity. Turbulent transport quenching due to the neoclassically predicted radial electric field profile is needed in predictive transport simulations to reproduce the peaking of the measured electron temperature profile [Guttenfelder et al., Phys. Rev. Lett. 101, 215002 (2008)].

  16. Oxidative stress due to radiation in CD34+ hematopoietic progenitor cells. Protection by IGF-1

    International Nuclear Information System (INIS)

    Floratou, K.; Karakantza, M.; Giannopoulou, E.; Antonacopoulou, A.; Adonakis, G.; Kardamakis, D.; Matsouka, P.

    2012-01-01

    Radiation exerts direct as well as indirect effects on DNA through the generation of reactive oxygen species (ROS). Irradiated hematopoietic progenitor cells (HPCs) experience DNA strand breaks, favoring genetic instability, due to ROS generation. Our aim was to study the effect of a range of radiation doses in HPCs and the possible protective mechanisms activated by insulin-like growth factor-1 (IGF-1). ROS generation was evaluated, in the presence or absence of IGF-1 in liquid cultures of human HPCs-CD34 + irradiated with 1-, 2- and 5-Gy X-rays, using a flow cytometry assay. Manganese superoxide dismutase (MnSOD) expression was studied by western blot analysis and visualized by an immunofluorescence assay. Apoptosis was estimated using the following assays: Annexin-V assay, DNA degradation assay, BCL-2/BAX mRNA and protein levels and caspase-9 protein immunofluorescence visualization. Viability and clonogenic potential were studied in irradiated HPCs. The generation of superoxide anion radicals at an early and a late time point was increased, while the hydrogen peroxide generation at a late time point was stable. IGF-1 presence further enhanced the radiation-induced increase of MnSOD at 24 h post irradiation. IGF-1 inhibited the mitochondria-mediated pathway of apoptosis by regulating the m-RNA and protein expression of BAX, BCL-2 and the BCL-2/BAX ratio and by decreasing caspase-9 protein expression. IGF-1 presence in culture media of irradiated cells restored the clonogenic capacity and the viability of HPCs as well. In conclusion, IGF-1 protects HPCs-CD34 + from radiation effects, by eliminating the oxidative microenvironment through the enhancement of MnSOD activation and by regulating the mitochondria-mediated pathway of apoptosis. (author)

  17. The measurement of internal stress fields in weldments and around cracks using high resolution neutron diffraction

    International Nuclear Information System (INIS)

    Allen, A.J.; Hutchings, M.T.; Windsor, C.G.

    1987-01-01

    The paper describes and illustrates the capability of neutron diffraction to measure the complete internal lattice macrostrain field, and hence the stress field, within steel components and weldments arising from their fabrication. A brief outline is given of the theory of the neutron method. The experimental considerations are discussed. The method is illustrated by its application to the measurement of the stress distribution in a:- uniaxially stressed mild steel rod, a double - V test weld, a tube-plate weld, and a cracked fatigue test specimen. (U.K.)

  18. Transient Stress Intensity Factors of Functionally Graded Hollow Cylinders with Internal Circumferential Cracks

    Directory of Open Access Journals (Sweden)

    Iman Eshraghi

    Full Text Available Abstract In this paper, transient thermomechanical stress intensity factors for functionally graded cylinders with complete internal circumferential cracks are obtained using the weight function method. The finite difference method is used to calculate the time dependent temperature distribution and thermal stresses along the cylinder thickness. Furthermore, finite element analysis is performed to determine the weight function coefficients and to investigate the accuracy of the predicted stress intensity factors from the weight functions. Variation of the stress intensity factors with time and effects of the material gradation on the results are investigated, as well. It is shown that the proposed technique can be used to accurately predict transient thermomechanical stress intensity factors for functionally graded cylinders with arbitrary material gradation.

  19. Two different mechanisms of fatigue damage due to cyclic stress loading at 77 K for MOCVD-YBCO-coated conductors

    International Nuclear Information System (INIS)

    Sugano, M; Yoshida, Y; Hojo, M; Shikimachi, K; Hirano, N; Nagaya, S

    2008-01-01

    Tensile fatigue tests were carried out at 77 K for YBCO-coated conductors fabricated by metal-organic chemical vapor deposition (MOCVD). The S-N relationship, variation of critical current (I c ) during cyclic loading and microscopic fatigue damage were investigated. Fatigue strength at 10 6 cycles was evaluated to be σ max = 1300 MPa and 890 MPa under the stress ratios of 0.5 and 0.1. Two different mechanisms of fatigue damage, depending on the number of stress cycles to failure, were observed. In one of the fracture mechanisms, fatigue behavior is characterized by overall fracture which occurs at 10 4 -10 5 cycles. For these specimens, I c after unloading does not degrade before overall fracture. Although only shallow slip bands were found at the Ag surface, fatigue cracks were found on the Hastelloy C-276 surface of the fractured specimen. These results suggest that overall fracture due to cyclic stress was caused by fatigue of the Hastelloy substrate. In the other fracture mechanism, even though overall fracture did not occur at 10 6 cycles, a slight decrease of I c was detected after 10 5 cycles. No fatigue crack was found on the Hastelloy surface, while deep slip bands corresponding to the initial stage of fatigue crack were observed on the Ag surface. From these results, we concluded that I c degradation at a high cycle number is attributed to the fatigue of the Ag stabilizing layer

  20. Internal Stress Monitoring of In-Service Structural Steel Members with Ultrasonic Method

    Science.gov (United States)

    Li, Zuohua; He, Jingbo; Teng, Jun; Wang, Ying

    2016-01-01

    Internal stress in structural steel members is an important parameter for steel structures in their design, construction, and service stages. However, it is hard to measure via traditional approaches. Among the existing non-destructive testing (NDT) methods, the ultrasonic method has received the most research attention. Longitudinal critically refracted (Lcr) waves, which propagate parallel to the surface of the material within an effective depth, have shown great potential as an effective stress measurement approach. This paper presents a systematic non-destructive evaluation method to determine the internal stress in in-service structural steel members using Lcr waves. Based on theory of acoustoelasticity, a stress evaluation formula is derived. Factor of stress to acoustic time difference is used to describe the relationship between stress and measurable acoustic results. A testing facility is developed and used to demonstrate the performance of the proposed method. Two steel members are measured by using the proposed method and the traditional strain gauge method for verification. Parametric studies are performed on three steel members and the aluminum plate to investigate the factors that influence the testing results. The results show that the proposed method is effective and accurate for determining stress in in-service structural steel members. PMID:28773347

  1. Internal Stress Monitoring of In-Service Structural Steel Members with Ultrasonic Method.

    Science.gov (United States)

    Li, Zuohua; He, Jingbo; Teng, Jun; Wang, Ying

    2016-03-23

    Internal stress in structural steel members is an important parameter for steel structures in their design, construction, and service stages. However, it is hard to measure via traditional approaches. Among the existing non-destructive testing (NDT) methods, the ultrasonic method has received the most research attention. Longitudinal critically refracted (Lcr) waves, which propagate parallel to the surface of the material within an effective depth, have shown great potential as an effective stress measurement approach. This paper presents a systematic non-destructive evaluation method to determine the internal stress in in-service structural steel members using Lcr waves. Based on theory of acoustoelasticity, a stress evaluation formula is derived. Factor of stress to acoustic time difference is used to describe the relationship between stress and measurable acoustic results. A testing facility is developed and used to demonstrate the performance of the proposed method. Two steel members are measured by using the proposed method and the traditional strain gauge method for verification. Parametric studies are performed on three steel members and the aluminum plate to investigate the factors that influence the testing results. The results show that the proposed method is effective and accurate for determining stress in in-service structural steel members.

  2. Stress and turnover intent in international organizations: social support and work life balance as resources

    OpenAIRE

    Giauque, David; Anderfuhren-Biget, Simon; Varone, Frédéric

    2016-01-01

    This study investigates whether work opportunities have an impact on stress and the related turnover intentions of employees working in intergovernmental international organizations. It contextualizes the job resources and demands model within international organizations’ specific work conditions. The empirical test is based on original data from a survey administered in four major organizations of the United Nations system. Results demonstrate that social work opportunities and work-life bal...

  3. Show what you know and deal with stress yourself: a qualitative interview study of medical interns' perceptions of stress and gender.

    Science.gov (United States)

    Verdonk, Petra; Räntzsch, Viktoria; de Vries, Remko; Houkes, Inge

    2014-05-17

    Medical students report high stress levels and in particular, the clinical phase is a demanding one. The field of medicine is still described as having a patriarchal culture which favors aspects like a physicians' perceived certainty and rationalism. Also, the Effort-Recovery Model explains stress as coming from a discrepancy between job demands, job control, and perceived work potential. Gendered differences in stress are reported, but not much is known about medical interns' perceptions of how gender plays in relation to stress. The aim of this study is to explore how medical interns experience and cope with stress, as well as how they reflect on the gendered aspects of stress. In order to do this, we have performed a qualitative study. In 2010-2011, semi-structured qualitative interviews were conducted with seventeen medical interns across all three years of the Masters programme (6 male, 11 female) at a Dutch medical school. The interview guide is based on gender theory, the Effort-Recovery Model, and empirical literature. Transcribed interviews have been analyzed thematically. First, stress mainly evolves from having to prove one's self and show off competencies and motivation ("Show What You Know…"). Second, interns seek own solutions for handling stress because it is not open for discussion (… "And Deal With Stress Yourself"). Patient encounters are a source of pride and satisfaction rather than a source of stress. But interns report having to present themselves as 'professional and self-confident', remaining silent about experiencing stress. Female students are perceived to have more stress and to study harder in order to live up to expectations. The implicit message interns hear is to remain silent about insecurities and stress, and, in particular, female students might face disadvantages. Students who feel less able to manifest the 'masculine protest' may benefit from a culture that embraces more collaborative styles, such as having open conversation

  4. Exploring valid internal-control genes in Porphyra yezoensis (Bangiaceae) during stress response conditions

    Science.gov (United States)

    Wang, Wenlei; Wu, Xiaojie; Wang, Chao; Jia, Zhaojun; He, Linwen; Wei, Yifan; Niu, Jianfeng; Wang, Guangce

    2014-07-01

    To screen the stable expression genes related to the stress (strong light, dehydration and temperature shock) we applied Absolute real-time PCR technology to determine the transcription numbers of the selected test genes in P orphyra yezoensis, which has been regarded as a potential model species responding the stress conditions in the intertidal. Absolute real-time PCR technology was applied to determine the transcription numbers of the selected test genes in P orphyra yezoensis, which has been regarded as a potential model species in stress responding. According to the results of photosynthesis parameters, we observed that Y(II) and F v/ F m were significantly affected when stress was imposed on the thalli of P orphyra yezoensis, but underwent almost completely recovered under normal conditions, which were collected for the following experiments. Then three samples, which were treated with different grade stresses combined with salinity, irradiation and temperature, were collected. The transcription numbers of seven constitutive expression genes in above samples were determined after RNA extraction and cDNA synthesis. Finally, a general insight into the selection of internal control genes during stress response was obtained. We found that there were no obvious effects in terms of salinity stress (at salinity 90) on transcription of most genes used in the study. The 18S ribosomal RNA gene had the highest expression level, varying remarkably among different tested groups. RPS8 expression showed a high irregular variance between samples. GAPDH presented comparatively stable expression and could thus be selected as the internal control. EF-1α showed stable expression during the series of multiple-stress tests. Our research provided available references for the selection of internal control genes for transcripts determination of P. yezoensis.

  5. Development of a Method to Assess the Radiation Dose due to Internal Exposure to Short-lived Radioactive Materials

    International Nuclear Information System (INIS)

    Benmaman, D.; Koch, J.; Ribak, J.

    2014-01-01

    Work with radioactive materials requires monitoring of the employees' exposure to ionizing radiation. Employees may be exposed to radiation from internal and/or external exposure. Control of external exposure is mostly conducted through personal radiation dosimeters provided to employees. Control of internal exposure can be performed by measuring the concentration of radioactive substances excreted in urine or through whole-body counting in which the entire body or target organs are scanned with a sensitive detector system (1). According to the regulations in Israel an employee that may be internally exposed must undergo an exposure control at least once every three months. The idea lying behind the control of internal exposure by urine testing is that if radioactive material has penetrated into the employee body, it can be detected even if the test is performed once every three months. A model was fitted for each element describing its dispersion in the body and its excretion therefrom (2). By means of this model, one can estimate the activity that entered the body and calculate the resulting radiation dose to which the worker was exposed. There is a problem to implement this method when it comes to short-lived radioactive materials, for which it is very likely that the material that penetrated into the body has decayed and cannot be detected by testing once every three months. As a result, workers with short-lived radioactive materials are presently not monitored for internal exposure, in contradiction to the requirements of the Safety at Work Regulations. The purpose of the study is to develop an alternative method to assess the amount of radioactive material absorbed in the body and the resulting radiation dose due to internal exposure of workers to short-lived radioactive materials

  6. Comorbidity in illness-induced posttraumatic stress disorder versus posttraumatic stress disorder due to external events in a nationally representative study.

    Science.gov (United States)

    Sommer, Jordana L; Mota, Natalie; Edmondson, Donald; El-Gabalawy, Renée

    2018-05-10

    The current study compared physical and mental health characteristics and quality of life of illness-induced posttraumatic stress disorder (PTSD) versus those with PTSD due to external traumatic events in a population-based sample. PTSD was assessed with the Alcohol Use Disorder and Associated Disabilities Interview Schedule (AUDADIS-5) using DSM-5 criteria in the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions. Participants with past-year PTSD (n = 1779) were categorized into two groups: illness-induced (6.5%) and other trauma-induced PTSD (92.9%) based on index trauma. Group differences in physical health, mental health, and quality of life were estimated using multiple logistic and linear regressions with adjustment for demographics and medical morbidity. Compared to PTSD due to external events, illness-induced PTSD had higher rates of life-threatening illness in the past year. Illness-induced PTSD compared to PTSD due to external events was associated with reduced odds of depressive/bipolar disorders and antisocial personality disorder, but increased odds of cannabis use disorder. The groups did not differ on quality of life after accounting for medical morbidity. Illness-induced PTSD is common among American adults and has a similar impact on quality of life as PTSD due to external events, but may have distinct mental health correlates. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. A numerical study of internal brick stresses in AGR moderator bricks

    Energy Technology Data Exchange (ETDEWEB)

    McNally, K., E-mail: kevin.mcnally@hsl.gsi.gov.uk [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Fahad, M. [NGRG, School of MACE, University of Manchester, Manchester M13 9PL (United Kingdom); Tan, E.; Warren, N. [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Hall, G.N.; Marsden, B.J. [NGRG, School of MACE, University of Manchester, Manchester M13 9PL (United Kingdom)

    2016-12-01

    Highlights: • A methodology for studying the uncertainty in internal brick stresses was developed. • A computationally efficient methodology based upon a surrogate model was utilised. • Uncertainty in material relationships, particularly those related to secondary creep was the dominant source of uncertainty. - Abstract: Physically-based models are often used to model changes in geometry and the associated stress fields of graphite moderator bricks within an advanced gas-cooled reactor (AGR). These models require inputs that describe the loading conditions, and coded relationships describing the behaviour of material properties. Material relationships are primarily based upon data obtained from inspection campaigns at operating reactors. However, the data from trepanning campaigns do not provide information on some of the key relationships and parameters that affect the internal stresses generated within the moderator bricks. In this work we explore how uncertain material property relationships affect the internal brick stresses in early- and late-life. We describe two computer experiments designed to study early- and late-life brick stresses and report the results from global sensitivity analysis of the models. The work makes use of an emulator, a surrogate for the FE model, in order to make the sensitivity analyses computationally feasible.

  8. A numerical study of internal brick stresses in AGR moderator bricks

    International Nuclear Information System (INIS)

    McNally, K.; Fahad, M.; Tan, E.; Warren, N.; Hall, G.N.; Marsden, B.J.

    2016-01-01

    Highlights: • A methodology for studying the uncertainty in internal brick stresses was developed. • A computationally efficient methodology based upon a surrogate model was utilised. • Uncertainty in material relationships, particularly those related to secondary creep was the dominant source of uncertainty. - Abstract: Physically-based models are often used to model changes in geometry and the associated stress fields of graphite moderator bricks within an advanced gas-cooled reactor (AGR). These models require inputs that describe the loading conditions, and coded relationships describing the behaviour of material properties. Material relationships are primarily based upon data obtained from inspection campaigns at operating reactors. However, the data from trepanning campaigns do not provide information on some of the key relationships and parameters that affect the internal stresses generated within the moderator bricks. In this work we explore how uncertain material property relationships affect the internal brick stresses in early- and late-life. We describe two computer experiments designed to study early- and late-life brick stresses and report the results from global sensitivity analysis of the models. The work makes use of an emulator, a surrogate for the FE model, in order to make the sensitivity analyses computationally feasible.

  9. Association of Acculturative Stress, Islamic Practices, and Internalizing Symptoms among Arab American Adolescents

    Science.gov (United States)

    Goforth, Anisa N.; Pham, Andy V.; Chun, Heejung; Castro-Olivo, Sara M.; Yosai, Erin R.

    2016-01-01

    Although the numbers of Arab American immigrant youth in schools is increasing, there is little understanding of their mental health and the sociocultural factors that might influence it. This study examined the relationship between 2 sociocultural factors (i.e., acculturative stress and religious practices) and internalizing symptoms in first-…

  10. Correlates and Predictors of Parenting Stress among Internationally Adopting Mothers: A Longitudinal Investigation

    Science.gov (United States)

    Viana, Andres G.; Welsh, Janet A.

    2010-01-01

    This study examined correlates and predictors of parenting stress among internationally adopting (IA) mothers with the goal of expanding the knowledge base on the experiences of adoptive parents. One hundred and forty-three IA mothers completed pre-adoption (Time 0) and six months post-adoption (Time 1) surveys with questions regarding child-,…

  11. The co-development of parenting stress and childhood internalizing and externalizing problems

    NARCIS (Netherlands)

    Stone, L.L.; Mares, S.H.W.; Otten, R.; Engels, R.C.M.E.; Janssens, J.M.A.M.

    2016-01-01

    Although the detrimental influence of parenting stress on child problem behavior is well established, it remains unknown how these constructs affect each other over time. In accordance with a transactional model, this study investigates how the development of internalizing and externalizing problems

  12. Evaluation of stress intensity factor for craks in surface of tubes with internal pressure

    International Nuclear Information System (INIS)

    Cesari, F.; Hellen, T.K.

    1977-01-01

    In this report the authors have examined the different methods for calculation of the stress intensity factor in tubes subject at internal pressure with surface cracks. The analysis includes cracks in 2-D axialsymmetric and 3-D. Moreover the authors have clarified the difference between the ASME Sec.11 and the procedure more rigorous

  13. Managing the Role Stress of Public Relations Practitioners in International Schools

    Science.gov (United States)

    Bunnell, Tristan

    2006-01-01

    This article examines the diverse role and work of public relations practitioners in the growing body of international schools. It examines evidence of "role stress" in the form of the subsets of role overload, role ambiguity, role conflict and role preparedness. Three particular aspects were identified. The role seems prone to change alongside…

  14. Monitoring stress among internal medicine residents: an experience-driven, practical and short measure.

    Science.gov (United States)

    Myszkowski, Nils; Villoing, Barbara; Zenasni, Franck; Jaury, Philippe; Boujut, Emilie

    2017-07-01

    Residents experience severely high levels of stress, depression and burnout, leading to perceived medical errors, as well as to symptoms of impairment, such as chronic anger, cognitive impairment, suicidal behavior and substance abuse. Because research has not yet provided a psychometrically robust population-specific tool to measure the level of stress of medicine residents, we aimed at building and validating such a measure. Using an inductive scale development approach, a short, pragmatic measure was built, based on the interviews of 17 medicine residents. The Internal Medicine Residency Stress Scale (IMRSS) was then administered in a sample of 259 internal medicine residents (199 females, 60 males, M Age  = 25.6) along with the Hospital Anxiety and Depression Scale, Maslach Burnout Inventory, Satisfaction With Life Scale and Ways of Coping Checklist. The IMRSS showed satisfactory internal reliability (Cronbach's α = .86), adequate structural validity - studied through Confirmatory Factor Analysis (χ 2 /df = 2.51, CFI = .94; SRMR = .037, RMSEA = .076) - and good criterion validity - the IMRSS was notably strongly correlated with emotional exhaustion (r = .64; p is recommended to quickly and frequently assess and monitor stress among internal medicine residents.

  15. XML Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

    Directory of Open Access Journals (Sweden)

    M. R. Monazzam Esmaielpou

    2015-09-01

    Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is reduced

  16. Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

    Directory of Open Access Journals (Sweden)

    M. R. Monazzam Esmaielpour

    2015-09-01

    Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. . Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. .Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. .Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is

  17. Deformation of a geo-medium with considering for internal self-balancing stresses

    Science.gov (United States)

    Lavrikov, S. V.; Revuzhenko, A. F.

    2016-11-01

    Based on the general concept of rock as a medium with inner sources and sinks of energy, the authors consider an approach to mathematical modeling of a geo-medium with account for internal self-balancing stresses. The description of stresses and strains at the level of microstructural elements and macrovolume of the medium uses methods of non-Archimedean analysis. The model allows describing the accumulation of elastic energy in the form of internal self-balancing stresses. A finite element algorithm and a software program for solving plane boundary-value problems have been developed. The calculated data on rock specimen compression are given. It is shown that the behavior of plastic deformation zones depends on the pre-assigned initial microstresses.

  18. Monitoring Changes in Croplands Due to Water Stress in the Krishna River Basin Using Temporal Satellite Imagery

    Directory of Open Access Journals (Sweden)

    Venkata Ramana Murthy Reddi

    2017-10-01

    Full Text Available Remote sensing-based assessments of large river basins such as the Krishna, which supplies water to many states in India, are useful for operationally monitoring agriculture, especially basins that are affected by abiotic stress. Moderate-Resolution Imaging Spectroradiometer (MODIS time series products can be used to understand cropland changes at the basin level due to abiotic stresses, especially water scarcity. Spectral matching techniques were used to identify land use/land cover (LULC areas for two crop years: 2013–2014, which was a normal year, and 2015–2016, which was a water stress year. Water stress-affected crop areas were categorized into three classes—severe, moderate and mild—based on the normalized difference vegetation index (NDVI and intensity of damage assessed through field sampling. Furthermore, ground survey data were used to assess the accuracy of MODIS-derived classification individual products. Water inflows into and outflows from the Krishna river basin during the study period were used as direct indicators of water scarcity/availability in the Krishna Basin. Furthermore, ground survey data were used to assess the accuracy of MODIS-derived LULC classification of individual year products. Rainfall data from the tropical rainfall monitoring mission (TRMM was used to support the water stress analysis. The nine LULC classes derived using the MODIS temporal imagery provided overall accuracies of 82% for the cropping year 2013–2014 and 85% for the year 2015–2016. Kappa values are 0.78 for 2013–2014 and 0.82 for 2015–2016. MODIS-derived cropland areas were compared with national statistics for the cropping year 2013–2014 with a R2 value of 0.87. Results show that both rainfed and irrigated areas in 2015–2016 saw significant changes that will have significant impacts on food security. It has been also observed that the farmers in the basin tend to use lower inputs and labour per ha during drought years. Among

  19. Extracranial internal carotid artery dissection caused by compression from a giant osteophyte due to atlantoaxial osteoarthritis: case report.

    Science.gov (United States)

    Ikedo, Taichi; Nakamura, Kazuhito; Sano, Noritaka; Nagata, Manabu; Okada, Yumiko; Kawakami, Taichiro; Murata, Takaho

    2017-10-01

    Deformed osseous structures have been reported as rare causes of extracranial internal carotid artery (ICA) dissection, including the styloid process and the hyoid bone. Here, the authors describe the first known case of symptomatic ICA dissection caused by a giant osteophyte due to atlantoaxial osteoarthritis. The left ICA was fixed at the skull base and at the ICA portion compressed by the osteophyte, and it was highly stretched and injured between the two portions during neck rotation. The patient was successfully treated with ligation of the affected ICA following balloon test occlusion. Atlantoaxial osteoarthritis should be considered in the differential diagnosis of ICA dissection in patients with a severely deformed cervical spine.

  20. A simplified method of evaluating the stress wave environment of internal equipment

    Science.gov (United States)

    Colton, J. D.; Desmond, T. P.

    1979-01-01

    A simplified method called the transfer function technique (TFT) was devised for evaluating the stress wave environment in a structure containing internal equipment. The TFT consists of following the initial in-plane stress wave that propagates through a structure subjected to a dynamic load and characterizing how the wave is altered as it is transmitted through intersections of structural members. As a basis for evaluating the TFT, impact experiments and detailed stress wave analyses were performed for structures with two or three, or more members. Transfer functions that relate the wave transmitted through an intersection to the incident wave were deduced from the predicted wave response. By sequentially applying these transfer functions to a structure with several intersections, it was found that the environment produced by the initial stress wave propagating through the structure can be approximated well. The TFT can be used as a design tool or as an analytical tool to determine whether a more detailed wave analysis is warranted.

  1. Chronic stress enhances synaptic plasticity due to disinhibition in the anterior cingulate cortex and induces hyper-locomotion in mice.

    Science.gov (United States)

    Ito, Hiroshi; Nagano, Masatoshi; Suzuki, Hidenori; Murakoshi, Takayuki

    2010-01-01

    The anterior cingulate cortex (ACC) is involved in the pathophysiology of a variety of mental disorders, many of which are exacerbated by stress. There are few studies, however, of stress-induced modification of synaptic function in the ACC that is relevant to emotional behavior. We investigated the effects of chronic restraint stress (CRS) on behavior and synaptic function in layers II/III of the ACC in mice. The duration of field excitatory postsynaptic potentials (fEPSPs) was longer in CRS mice than in control mice. The frequency of miniature inhibitory postsynaptic currents (mIPSCs) recorded by whole-cell patch-clamping was reduced in CRS mice, while miniature excitatory postsynaptic currents (mEPSCs) remained unchanged. Paired-pulse ratios (PPRs) of the fEPSP and evoked EPSC were larger in CRS. There was no difference in NMDA component of evoked EPSCs between the groups. Both long-term potentiation (LTP) and long-term depression of fEPSP were larger in CRS mice than in control mice. The differences between the groups in fEPSP duration, PPRs and LTP level were not observed when the GABA(A) receptor was blocked by bicuculline. Compared to control mice, CRS mice exhibited hyper-locomotive activity in an open field test, while no difference was observed between the groups in anxiety-like behavior in a light/dark choice test. CRS mice displayed decreased freezing behavior in fear conditioning tests compared to control mice. These findings suggest that CRS facilitates synaptic plasticity in the ACC via increased excitability due to disinhibition of GABA(A) receptor signalling, which may underlie induction of behavioral hyper-locomotive activity after CRS. Copyright 2009 Elsevier Ltd. All rights reserved.

  2. Finite Element Modeling of Perturbation Fields due to Colonies of Stress Corrosion Cracks(SCCs) in a Gas Transmission Pipeline

    International Nuclear Information System (INIS)

    Yang, Sun Ho

    2001-01-01

    The detection of axial cracks using conventional MFL pig is a significant challenge in the gas pipeline inspection. In this study, a technique using interaction of circumferentially induced torrents with axial stress corrosion crack is presented. The feasibility of this technique is investigated using finite element modeling. Finite element analysis of such interaction is a difficult problem in terms of both computation time and memory requirements. The challenges arise due to the nonlinearity of material properties, the small sire of tight cracks relative to that of the magnetizer, and also time stepping involved in modeling velocity effects. This paper presents an approach based on perturbation methods. The overall analysis procedure is divided into 4 simple steps that can be performed sequentially. Modeling results show that this technique can effectively detect colonies of SCC as well as single SCC

  3. Il problema dei debiti internazionali nel periodo tra le due guerre mondiali. (The international debt problem in the interwar period

    Directory of Open Access Journals (Sweden)

    M. DE CECCO

    2013-12-01

    Full Text Available Grande attenzione è stata recentemente dedicata al problema attuale del debito del terzo mondo e le sue implicazioni per il sistema bancario internazionale . Una rassegna di eventi simili a volte precedenti in passato dimostra che gli operatori dei mercati finanziari internazionali hanno la memoria corta , poiché la maggior parte degli aspetti della crisi si sono verificati in passato. Questo è confermato dal considerare il problema del debito internazionale tra la prima e la seconda guerra mondiale . La principale differenza tra allora e adesso è che il periodo tra le due guerre fu un periodo di transizione da un sistema di commercio dominato daòòa sterlina ad uno dominato  dal dollaro statunitense . Molti dei problemi di oggi derivano da questa continua dominazione dollaroConsiderable attention has recently been paid to the current problem of third world debt and its implications for the international banking system. A review of similar events at previous times in the past shows that operators in international financial markets have very short memories, since most of the aspects of the current crisis have occurred in the past. This is borne out by considering the international debt problem between the first and second world wars. The major difference between then and now is that the interwar period was a time of transition from a sterling-dominated trading system to one dominated by the US dollar. Many of today's problems stem from this continuing dollar domination.JEL: N24

  4. A thin rivulet or ridge subject to a uniform transverse shear stress at its free surface due to an external airflow

    KAUST Repository

    Sullivan, J. M.; Paterson, C.; Wilson, S. K.; Duffy, B. R.

    2012-01-01

    We use the lubrication approximation to analyze three closely related problems involving a thin rivulet or ridge (i.e., a two-dimensional droplet) of fluid subject to a prescribed uniform transverse shear stress at its free surface due

  5. Propagation of internal stresses in composite materials during heating and cooling according to thermal cycles of welding

    International Nuclear Information System (INIS)

    Gukasyan, L.E.; Belov, V.V.

    1977-01-01

    Investigations of free thermal expansion of a composite material, of fibre and matrix during welding thermal cycle make it possible to estimate mean internal strain and stress in the composite components, as well as the residual internal stress and strain present in the composite material after manufacturing. The samples investigated consisted of nickel-chromium EhI445 alloy, reinforced by tungsten-rhenium alloy fibres. As the composite material was cooled and heated in course of welding, the stress and strain changed their sign twice, the first time upon heating, the second time upon cooling. After complete cooling of the composite material residual stresses in the fibre stay at the proportionality level, while those in the matrix are lower. Experimental evidence of internal stress and strain appearing in the composite material during heating are fairly consistent with calculations in the elastic region, if account is taken of the temperature of internal residual stress relaxation upon heating

  6. An Analysis of 19 International Case Studies of Stress Prevention Through Work Reorganization Using the Demand/Control Model

    Science.gov (United States)

    Karasek, Robert A.

    2004-01-01

    Nineteen international case studies of workplace stress prevention initiatives are analyzed. The focus of these cases, which span a variety of workplaces and locations, is on preventing stress through work reorganization rather than remedial approaches for stress relief. It is found that the majority of the occupations represented in the case…

  7. Stress intensity factors for complete internal and external cracks in spherical shells

    International Nuclear Information System (INIS)

    Chao, Y.J.; Chen, H.

    1989-01-01

    Cracks or flows found in the nuclear structure must be fully evaluated to assure the safety of the plant. The weight function method has been widely used in the determination of stress intensity factors for cracks under stress gradient e.g. for thermal shock loading. The unique features of the weight function method is that once the weight function for a particular cracked geometry is determined the stress intensity factors at the crack tip for any loading applied to the flawed structure can be calculated by a simple integration. In this paper the stress intensity factors of the complete, part-through internal and external cracks in a spherical shell are determined. The finite element method was used to develop the weight functions for the flawed geometry. The approximate crack surface profile was used to derive the weight functions. The stress intensity factors associated with the cracks in spherical shells under internal pressure are determined by both the weight functions and the direct finite element method

  8. TEMP-STRESS analysis of a reinforced concrete vessel under internal pressure

    International Nuclear Information System (INIS)

    Marchertas, A.H.; Kennedy, J.M.; Pfeiffer, P.A.

    1987-01-01

    Prediction of the response of the Sandia National laboratory 1/6-scale reinforced concrete containment model test was obtained by Argonne National Laboratory (ANL) employing a computer program developed by ANL. The test model was internally pressurized to failure. The two-dimensional code TEMP-STRESS [1-5] has been developed at ANL for stress analysis of plane and axisymmetric 2-D reinforced structures under various thermal conditions. The program is applicable to a wide variety of nonlinear problems, and is utilized in the present study. The comparison of these pretest computations with test data on the containment model should be a good indication of the state of the code

  9. Stress Corrosion Evaluation of Various Metallic Materials for the International Space Station Water Recycling System

    Science.gov (United States)

    Torres, P. D.

    2015-01-01

    A stress corrosion evaluation was performed on Inconel 625, Hastelloy C276, titanium commercially pure (TiCP), Ti-6Al-4V, Ti-6Al-4V extra low interstitial, and Cronidur 30 steel as a consequence of a change in formulation of the pretreatment for processing the urine in the International Space Station Environmental Control and Life Support System Urine Processing Assembly from a sulfuric acid-based to a phosphoric acid-based solution. The first five listed were found resistant to stress corrosion in the pretreatment and brine. However, some of the Cronidur 30 specimens experienced reduction in load-carrying ability.

  10. Role of Reynolds stress and toroidal momentum transport in the dynamics of internal transport barriers

    International Nuclear Information System (INIS)

    Kim, S. S.; Jhang, Hogun; Diamond, P. H.

    2012-01-01

    We study the interplay between intrinsic rotation and internal transport barrier (ITB) dynamics through the dynamic change of the parallel Reynolds stress. Global flux-driven gyrofluid simulations are used for this study. In particular, we investigate the role of parallel velocity gradient instability (PVGI) in the ITB formation and the back transition. It is found that the excitation of PVGI is followed by a change in the Reynolds stress which drives a momentum redistribution. This significantly influences E×B shear evolution and subsequent ITB dynamics. Nonlocal interactions among fluctuations are also observed during the PVGI excitation, resulting in turbulence suppression at the ITB.

  11. Only-Child Status in Relation to Perceived Stress and Studying-Related Life Satisfaction among University Students in China: A Comparison with International Students.

    Science.gov (United States)

    Chu, Janet Junqing; Khan, Mobarak Hossain; Jahn, Heiko J; Kraemer, Alexander

    2015-01-01

    University students in general face multiple challenges, which may affect their levels of perceived stress and life satisfaction. Chinese students currently face specific strains due to the One-Child Policy (OCP). The aim of this study was to assess (1) whether the levels of perceived stress and studying-related life satisfaction are associated with only-child (OC) status after controlling for demographic and socio-economic characteristics and (2) whether these associations differ between Chinese and international students. A cross-sectional health survey based on a self-administrated standardised questionnaire was conducted among 1,843 (1,543 Chinese, 300 international) students at two Chinese universities in 2010-2011. Cohen's Perceived Stress Scale (PSS-14) and Stock and Kraemer's Studying-related Life Satisfaction Scale were used to measure perceived stress and studying-related life satisfaction respectively. Multivariable logistic regression analyses were used to examine the associations of OC status with perceived stress and studying-related life satisfaction by sex for Chinese students and international students separately. The Chinese non-only-children (NOCs) were more likely to come from small cities. Multivariable regression models indicate that the Chinese NOCs were more stressed than OCs (OR = 1.39, 1.11-1.74) with a stronger association in men (OR = 1.48, 1.08-2.02) than women (OR = 1.26, 0.89-1.77). NOCs were also more dissatisfied than their OC fellows in the Chinese subsample (OR = 1.37, 1.09-1.73). Among international students, no associations between OC status and perceived stress or studying-related life satisfaction were found. To promote equality between OCs and NOCs at Chinese universities, the causes of more stress and less studying-related life satisfaction among NOCs compared to OCs need further exploration.

  12. Only-Child Status in Relation to Perceived Stress and Studying-Related Life Satisfaction among University Students in China: A Comparison with International Students.

    Directory of Open Access Journals (Sweden)

    Janet Junqing Chu

    Full Text Available University students in general face multiple challenges, which may affect their levels of perceived stress and life satisfaction. Chinese students currently face specific strains due to the One-Child Policy (OCP. The aim of this study was to assess (1 whether the levels of perceived stress and studying-related life satisfaction are associated with only-child (OC status after controlling for demographic and socio-economic characteristics and (2 whether these associations differ between Chinese and international students.A cross-sectional health survey based on a self-administrated standardised questionnaire was conducted among 1,843 (1,543 Chinese, 300 international students at two Chinese universities in 2010-2011. Cohen's Perceived Stress Scale (PSS-14 and Stock and Kraemer's Studying-related Life Satisfaction Scale were used to measure perceived stress and studying-related life satisfaction respectively. Multivariable logistic regression analyses were used to examine the associations of OC status with perceived stress and studying-related life satisfaction by sex for Chinese students and international students separately.The Chinese non-only-children (NOCs were more likely to come from small cities. Multivariable regression models indicate that the Chinese NOCs were more stressed than OCs (OR = 1.39, 1.11-1.74 with a stronger association in men (OR = 1.48, 1.08-2.02 than women (OR = 1.26, 0.89-1.77. NOCs were also more dissatisfied than their OC fellows in the Chinese subsample (OR = 1.37, 1.09-1.73. Among international students, no associations between OC status and perceived stress or studying-related life satisfaction were found.To promote equality between OCs and NOCs at Chinese universities, the causes of more stress and less studying-related life satisfaction among NOCs compared to OCs need further exploration.

  13. Only-Child Status in Relation to Perceived Stress and Studying-Related Life Satisfaction among University Students in China: A Comparison with International Students

    Science.gov (United States)

    Chu, Janet Junqing; Khan, Mobarak Hossain; Jahn, Heiko J.; Kraemer, Alexander

    2015-01-01

    Objectives University students in general face multiple challenges, which may affect their levels of perceived stress and life satisfaction. Chinese students currently face specific strains due to the One-Child Policy (OCP). The aim of this study was to assess (1) whether the levels of perceived stress and studying-related life satisfaction are associated with only-child (OC) status after controlling for demographic and socio-economic characteristics and (2) whether these associations differ between Chinese and international students. Materials and Methods A cross-sectional health survey based on a self-administrated standardised questionnaire was conducted among 1,843 (1,543 Chinese, 300 international) students at two Chinese universities in 2010–2011. Cohen’s Perceived Stress Scale (PSS-14) and Stock and Kraemer’s Studying-related Life Satisfaction Scale were used to measure perceived stress and studying-related life satisfaction respectively. Multivariable logistic regression analyses were used to examine the associations of OC status with perceived stress and studying-related life satisfaction by sex for Chinese students and international students separately. Results The Chinese non-only-children (NOCs) were more likely to come from small cities. Multivariable regression models indicate that the Chinese NOCs were more stressed than OCs (OR = 1.39, 1.11–1.74) with a stronger association in men (OR = 1.48, 1.08–2.02) than women (OR = 1.26, 0.89–1.77). NOCs were also more dissatisfied than their OC fellows in the Chinese subsample (OR = 1.37, 1.09–1.73). Among international students, no associations between OC status and perceived stress or studying-related life satisfaction were found. Conclusions To promote equality between OCs and NOCs at Chinese universities, the causes of more stress and less studying-related life satisfaction among NOCs compared to OCs need further exploration. PMID:26675032

  14. Forbearance coping, identification with heritage culture, acculturative stress, and psychological distress among Chinese international students.

    Science.gov (United States)

    Wei, Meifen; Liao, Kelly Yu-Hsin; Heppner, Puncky Paul; Chao, Ruth Chu-Lien; Ku, Tsun-Yao

    2012-01-01

    Based on Berry's (1997) theoretical framework for acculturation, our goal in this study was to examine whether the use of a culturally relevant coping strategy (i.e., forbearance coping, a predictor) would be associated with a lower level of psychological distress (a psychological outcome), for whom (i.e., those with weaker vs. stronger identification with heritage culture, a moderator), and under what situations (i.e., lower vs. higher acculturative stress, a moderator). A total of 188 Chinese international students completed an online survey. Results from a hierarchical regression indicated a significant 3-way interaction of forbearance coping, identification with heritage culture, and acculturative stress on psychological distress. For those with a weaker identification with their heritage culture, when acculturative stress was higher, the use of forbearance coping was positively associated with psychological distress. However, this was not the case when acculturative stress was lower. In other words, the use of forbearance coping was not significantly associated with psychological distress when acculturative stress was lower. Moreover, for those with a stronger cultural heritage identification, the use of forbearance coping was not significantly associated with psychological distress regardless of whether acculturative stress was high or low. Future research and implications are discussed. (c) 2012 APA, all rights reserved.

  15. A randomized controlled trial of mindfulness to reduce stress and burnout among intern medical practitioners.

    Science.gov (United States)

    Ireland, Michael J; Clough, Bonnie; Gill, Kim; Langan, Fleur; O'Connor, Angela; Spencer, Lyndall

    2017-04-01

    Stress and burnout are highly prevalent among medical doctors, and are associated with negative consequences for doctors, patients, and organizations. The purpose of the current study was to examine the effectiveness of a mindfulness training intervention in reducing stress and burnout among medical practitioners, by means of a Randomised Controlled Trial design. Participants were 44 intern doctors completing an emergency department rotation in a major Australian hospital. Participants were randomly assigned to either an active control (one hour extra break per week) or the 10-week mindfulness training intervention. Measures of stress and burnout were taken pre-, mid- and post intervention. Participants undergoing the 10-week mindfulness training program reported greater improvements in stress and burnout relative to participants in the control condition. Significant reduction in stress and burnout was observed for participants in the mindfulness condition. No such reductions were observed for participants in the control condition. Mindfulness interventions may provide medical practitioners with skills to effectively manage stress and burnout, thereby reducing their experience of these symptoms. It is likely that doctors would benefit from the inclusion of such a training program as a part of their general medical education.

  16. Evaluation of creep damage due to stress relaxation in SA533 grade B class 1 and SA508 class 3 pressure vessel steels

    International Nuclear Information System (INIS)

    Hoffmann, C.L.; Urko, W.

    1993-01-01

    Creep damage can result from stress relaxation of residual stresses in components when exposed to high temperature thermal cycles. Pressure vessels, such as the reactor vessel of the modular high-temperature gas reactor (MHTGR), which normally operate at temperatures well below the creep range can develop relatively high residual stresses in high stress locations. During short term excursions to elevated-temperatures, creep damage can be produced by the loadings on the vessel. In addition, residual stresses will relax out, causing greater creep damage in the pressure vessel material than might otherwise be calculated. The evaluation described in this paper assesses the magnitude of the creep damage due to relaxation of residual stresses resulting from short term exposure of the pressure vessel material to temperatures in the creep range. Creep relaxation curves were generated for SA533 Grade B, Class 1 and SA508 Class 3 pressure vessel steels using finite element analysis of a simple uniaxial truss loaded under constant strain conditions to produce an initial axial stress equal to 1.25 times the material yield strength at temperature. The strain is held constant for 1000 hours at prescribed temperatures from 700 F to 1000 F. The material creep law is used to calculate the relaxed stress for each time increment. The calculated stress relaxation versus time curves are compared with stress relaxation test data. Creep damage fractions are calculated by integrating the stress relaxation versus time curves and performing a linear creep damage summation using the minimum stress to rupture curves at the respective relaxation temperatures. Cumulative creep damage due to stress relaxation as a function of time and temperature is derived from the linear damage summation

  17. Internal stress distribution of X-ring using photoelastic experimental hybrid method

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Alunda Ouma [Dedan Kimathi University of Technology, Nyeri (Kenya); Hawong, Jai Sug; Lim, Hyun Seok [Yeungnam University, Gyeongsan (Korea, Republic of); Shin, Dong Chul [Koje College, Geoje (Korea, Republic of)

    2014-05-15

    Sealing elements are essential parts of many machines, and are used to prevent the loss of a fluid or gas. When such fluids are not properly sealed, catastrophic failures may result. Many different types of rings have been developed to suit various industrial needs. Considerable research has been done on the O-ring. We analyze the internal stresses developed in an X-ring under a uniform squeeze rate of 20%, which is suitable for static applications, using a photoelastic experimental hybrid method. The internal pressures applied were 0.98, 1.96, 2.94, 3.92, 4.90, and 5.88 MPa. We show that sealing rings with X geometry have considerably higher internal stresses than O-ring seals. In addition, we demonstrate that after extrusion, for an internal pressure of 5.88 MPa, the two lobes on the upper contact surface merge, thereby increasing the contact length of the upper side significantly. Extrusion in the X-ring occurred when the internal pressure was 4.90 MPa.

  18. Prediction of residual stresses and distortions due to laser beam welding of butt joints in pressure vessels

    International Nuclear Information System (INIS)

    Moraitis, G.A.; Labeas, G.N.

    2009-01-01

    A two-level three-dimensional Finite Element (FE) model has been developed to predict keyhole formation and thermo-mechanical response during Laser Beam Welding (LBW) of steel and aluminium pressure vessel or pipe butt-joints. A very detailed and localized (level-1) non-linear three-dimensional transient thermal model is initially developed, which simulates the mechanisms of keyhole formation, calculates the temperature distribution in the local weld area and predicts the keyhole size and shape. Subsequently, using a laser beam heat source model based on keyhole assumptions, a global (level-2) thermo-mechanical analysis of the LBW butt-joint is performed, from which the joint residual stresses and distortions are calculated. All the major physical phenomena associated to LBW, such as laser heat input via radiation, heat losses through convection and radiation, as well as latent heat are accounted for in the numerical model. Material properties and particularly enthalpy, which is very important due to significant material phase changes, are introduced as temperature-dependent functions. The main advantages of the developed model are its efficiency, flexibility and applicability to a wide range of LBW problems (e.g. welding for pressure vessel or pipework construction, welding of automotive, marine or aircraft components, etc). The model efficiency arises from the two-scale approach applied. Minimal or no experimental data are required for the keyhole size and shape computation by the level-1 model, while the thermo-mechanical response calculation by the level-2 model requires only process and material data. Therefore, it becomes possible to efficiently apply the developed simulation model to different material types and varying welding parameters (i.e. welding speed, heat source power, joint geometry, etc.) in order to control residual stresses and distortions within the welded structure

  19. False indications of {sup 95}Zr-{sup 95}Nb internal contamination due to contaminated sacred thread

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S P; Singh, I S; Sharma, R C [Internal Dosimetry Division, Bhabha Atomic Research Centre, BARC Hospital, Mumbai (India)

    2000-05-01

    Whole body monitoring of a worker showed an apparent internal contamination with a considerable amount of {sup 95}Zr-{sup 95}Nb. Inhalation exposure was suspected to have taken place about a week earlier when he had last worked in the radioactive area. Unexpected fast clearance indicated by the third periodical weekly follow up monitoring was considered to be an abnormal behaviour. Investigations revealed an external contamination on a sacred thread, which the worker was putting on across his thorax and not removing it at the time of bath due to religious considerations. These studies have underscored that short term follow up measurements data should be critically scrutinized and a caution should be exercised in the interpretation such data particularly in case of such relatively short lived radionuclides. (author)

  20. Dependence of ΔE effect on internal stresses in nickel: Experimental results by laser interferometry

    International Nuclear Information System (INIS)

    Chicharro, J.M.; Bayon, A.; Salazar, F.

    2006-01-01

    The speckle heterodyne interferometry is applied to the study of the dependence of Young's modulus on both the magnetic field and the internal stresses in a soft ferromagnetic material. Young's modulus is determined from the first natural longitudinal frequency of a slender magnetic rod positioned within a solenoid. Vibration of the sample is detected by an optical heterodyne system with a wide bandwidth. The samples are heated to above the Curie point and then cooled at several rates in order to induce different internal stresses. The study refers to nickel rods 10mm in diameter and 110mm in length. The grain sizes of the samples are also determined and related to changes in ΔE

  1. Dependence of {delta}E effect on internal stresses in nickel: Experimental results by laser interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Chicharro, J.M. [Dept. de Mecanica Aplicada e Ingenieria de Proyectos, E.T.S.I. Industriales, Universidad de Castilla-La Mancha, Avd. Camilo Jose Cela s/n, 13071 Ciudad Real (Spain)]. E-mail: josemanuel.chicharro@uclm.es; Bayon, A. [Dept. de Fisica Aplicada a los Recursos Naturales, E.T.S.I. Minas, Universidad Politecnica de Madrid, c/Rios Rosas, 21, 28003 Madrid (Spain); Salazar, F. [Dept. de Fisica Aplicada a los Recursos Naturales, E.T.S.I. Minas, Universidad Politecnica de Madrid, c/Rios Rosas, 21, 28003 Madrid (Spain)

    2006-02-15

    The speckle heterodyne interferometry is applied to the study of the dependence of Young's modulus on both the magnetic field and the internal stresses in a soft ferromagnetic material. Young's modulus is determined from the first natural longitudinal frequency of a slender magnetic rod positioned within a solenoid. Vibration of the sample is detected by an optical heterodyne system with a wide bandwidth. The samples are heated to above the Curie point and then cooled at several rates in order to induce different internal stresses. The study refers to nickel rods 10mm in diameter and 110mm in length. The grain sizes of the samples are also determined and related to changes in {delta}E.

  2. Stress Corrosion Evaluation of Nitinol 60 for the International Space Station Water Recycling System

    Science.gov (United States)

    Torres, P. D.

    2016-01-01

    A stress corrosion cracking (SCC) evaluation of Nitinol 60 was performed because this alloy is considered a candidate bearing material for the Environmental Control and Life Support System (ECLSS), specifically in the Urine Processing Assembly of the International Space Station. An SCC evaluation that preceded this one during the 2013-2014 timeframe included various alloys: Inconel 625, Hastelloy C-276, titanium (Ti) commercially pure (CP), Ti 6Al-4V, extra-low interstitial (ELI) Ti 6Al-4V, and Cronidur 30. In that evaluation, most specimens were exposed for a year. The results of that evaluation were published in NASA/TM-2015-218206, entitled "Stress Corrosion Evaluation of Various Metallic Materials for the International Space Station Water Recycling System,"1 available at the NASA Scientific and Technical Information program web page: http://www.sti.nasa.gov. Nitinol 60 was added to the test program in 2014.

  3. Influence of Transformation Plasticity on the Distribution of Internal Stress in Three Water-Quenched Cylinders

    Science.gov (United States)

    Liu, Yu; Qin, Shengwei; Zhang, Jiazhi; Wang, Ying; Rong, Yonghua; Zuo, Xunwei; Chen, Nailu

    2017-10-01

    Based on the hardenability of three medium carbon steels, cylinders with the same 60-mm diameter and 240-mm length were designed for quenching in water to obtain microstructures, including a pearlite matrix (Chinese steel mark: 45), a bainite matrix (42CrMo), and a martensite matrix (40CrNiMo). Through the combination of normalized functions describing transformation plasticity (TP), the thermo-elasto-plastic constitutive equation was deduced. The results indicate that the finite element simulation (FES) of the internal stress distribution in the three kinds of hardenable steel cylinders based on the proposed exponent-modified (Ex-Modified) normalized function is more consistent with the X-ray diffraction (XRD) measurements than those based on the normalized functions proposed by Abrassart, Desalos, and Leblond, which is attributed to the fact that the Ex-Modified normalized function better describes the TP kinetics. In addition, there was no significant difference between the calculated and measured stress distributions, even though TP was taken into account for the 45 carbon steel; that is, TP can be ignored in FES. In contrast, in the 42CrMo and 40CrNiMo alloyed steels, the significant effect of TP on the residual stress distributions was demonstrated, meaning that TP must be included in the FES. The rationality of the preceding conclusions was analyzed. The complex quenching stress is a consequence of interactions between the thermal and phase transformation stresses. The separated calculations indicate that the three steels exhibit similar thermal stress distributions for the same water-quenching condition, but different phase transformation stresses between 45 carbon steel and alloyed steels, leading to different distributions of their axial and tangential stresses.

  4. 1st International Symposium on Stress-Associated RNA Granules in Human Disease and Viral Infection

    Directory of Open Access Journals (Sweden)

    Bruce W. Banfield

    2014-09-01

    Full Text Available In recent years, important linkages have been made between RNA granules and human disease processes. On June 8-10 of this year, we hosted a new symposium, dubbed the 1st International Symposium on Stress-Associated RNA Granules in Human Disease and Viral Infection. This symposium brought together experts from diverse research disciplines ranging from cancer and neuroscience to infectious disease. This report summarizes speaker presentations and highlights current challenges in the field.

  5. Analysis of Effective and Internal Cyclic Stress Components in the Inconel Superalloy Fatigued at Elevated Temperature

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Miroslav; Petrenec, Martin; Polák, Jaroslav; Obrtlík, Karel; Chlupová, Alice

    2011-01-01

    Roč. 278, 4 July (2011), s. 393-398 ISSN 1022-6680. [European Symposium on Superalloys and their Application. Wildbad Kreuth, 25.5.2010-28.5.2010] R&D Projects: GA ČR GA106/08/1631 Institutional research plan: CEZ:AV0Z20410507 Keywords : low cycle fatigue * superalloys * high temperature * hysteresis loop * effective and internal stresses Subject RIV: JL - Materials Fatigue, Friction Mechanics; JL - Materials Fatigue, Friction Mechanics (UFM-A)

  6. Dip-Test Internal Stress and the Composite Model of Creep Deformation

    Czech Academy of Sciences Publication Activity Database

    Dobeš, Ferdinand; Orlová, Alena

    2005-01-01

    Roč. 482, - (2005), s. 291-294 ISSN 0255-5476. [Materials Structure & Micromechanics of Fracture /4./. Brno, 23.06.2004-25.06.2004] R&D Pro jects: GA AV ČR(CZ) IAA2041202 Institutional research plan: CEZ:AV0Z20410507 Keywords : creep * internal stress * subgrain Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.399, year: 2005

  7. Tungsten heavy metal alloys relations between the crystallographic texture and the internal stress distribution

    International Nuclear Information System (INIS)

    Nicolas, G.; Voltz, M.

    2001-01-01

    Quite often the W-Ni-Fe-Co heavy alloys are subjected to a thermomechanical processing of swaging and aging in order to obtain the highest possible level of resistance. Within the framework of this plastic deformation on cylindrical parts, the swaging leads to the distribution of morphological and crystallographic texture as well as specific internal stresses. The resulting mechanical characteristics are correlated to structural and sub-structural variations. (author)

  8. Honey bee (Apis mellifera) drones survive oxidative stress due to increased tolerance instead of avoidance or repair of oxidative damage

    Science.gov (United States)

    Oxidative stress can lead to premature aging symptoms and cause acute mortality at higher doses in a range of organisms. Oxidative stress resistance and longevity are mechanistically and phenotypically linked: considerable variation in oxidative stress resistance exists among and within species and ...

  9. Deformation path effects on the internal stress development in cold worked austenitic steel deformed in tension

    International Nuclear Information System (INIS)

    Ahmed, I.I.; Grant, B.; Sherry, A.H.; Quinta da Fonseca, J.

    2014-01-01

    The effects of cold work level and strain paths on the flow stress of austenitic stainless steels, including Bauschinger effect and associated internal stresses were investigated with both mechanical testing and neutron diffraction techniques. The main objective was to assess the effects of cold rolling: to 5%, 10%, 20% and 40% reduction and uniaxial straining on the evolution of the internal strains during the re-straining to 5% tensile strain in-situ, which is relevant for stress corrosion cracking (SCC) studies. The results of mechanical testing showed that the yield strength of material increased when it was reloaded in the forward direction and decreased well below the flow stress when the loading direction was reversed, showing a strong Bauschinger effect. The magnitude of Bauschinger effect is independent on whether tensile or compressive prestraining comes first but rather on the amount of prestrain. The assessment of the effect of prestraining methods showed that the magnitude of yield asymmetry was higher in the material prestrained by uniaxial deformation than those prestrained by cold rolling. Neutron diffraction test results showed that the elastic lattice strain difference between the maximum and minimum strain values increased consistently with the applied stress during the re-straining to 5% tensile strain in-situ along the 3 orthogonal directions of the rolled plate. It also emerged that, following the in-situ loading of cold rolled materials to 5% tensile strain, the largest strain difference occurred in the material prestrained to 20% reduction. In cold rolled samples, the peak width increased with cold work levels and during re-straining to 5% along rolling, transverse to rolling and normal directions which simulated reversed condition. In contrast to the cold rolled samples, there was neither increase nor decrease in the peak width of samples prestrained by uniaxial deformation on re-straining in reverse direction. This was rationalised in

  10. TEMP-STRESS analysis of a reinforced concrete vessel under internal pressure

    International Nuclear Information System (INIS)

    Marchertas, A.H.; Kennedy, J.M.; Pfeiffer, P.A.

    1987-01-01

    The TEMP-STRESS FEM represents an axisymmetric simulation of the reinforced concrete vessel to internal pressurization. The information shows the global deformation, the state of strain/stress within the containment vessel with respect to the imposed pressures. Thus, the location and progress of concrete cracking, the stretching of the liner and the reinforcing bars and final failure are indicated through the entire loading range. Equilibrium of the entire system is assured at definite loading increments. With the progress of concrete cracking, the resisting load is continuously transferred to the reinforcing bars and the liner. Thus, after the tensile strength is exceeded and the concrete stress is set to zero, the internal pressures are entirely resisted by the liner and the reserve strength of the reinforcing bars. The reinforcing bars are mechanically connected to each other by splices, the ultimate strength of which is less than that of the rebars themselves. The corresponding strain at this limiting stress is lower than the ultimate strain of the liner. Therefore, the specified ultimate strength of the splices limits the pressurization of the vessel. Furthermore, once any of the splices fail, then load is transferred to the adjacent members, causing their failure and general failure of the vessel. (orig./HP)

  11. Elevated temperature design of KALIMER reactor internals accounting for creep and stress-rupture effects

    International Nuclear Information System (INIS)

    Koo, Gyeong Hoi; Yoo, Bong

    2000-01-01

    In most LMFBR (Liquid Metal Fast Breed Reactor) design, the operating temperature is very high and the time-dependent creep and stress-rupture effects become so important in reactor structural design. Therefore, unlike with conventional PWR, the normal operating conditions can be basically dominant design loading because the hold time at elevated temperature condition is so long and enough to result in severe total creep ratcheting strains during total service lifetime. In this paper, elevated temperature design of the conceptually designed baffle annulus regions of KALIMER (Korea Advanced Liquid Metal Reactor) reactor internal structures is carried out for normal operating conditions which have the operating temperature 530 deg. C and the total service lifetime of 30 years. For the elevated temperature design of reactor internal structures, the ASME Code Case N-201-4 is used. Using this code, the time-dependent stress limits, the accumulated total inelastic strain during service lifetime, and the creep-fatigue damages are evaluated with the calculation results by the elastic analysis under conservative assumptions. The application procedures of elevated temperature design of the reactor internal structures using ASME code case N-201-4 with the elastic analysis method are described step by step in detail. This paper will be useful guide for actual application of elevated temperature design of various reactor types accounting for creep and stress-rupture effects. (author)

  12. Marital Processes, Neuroticism, and Stress as Risk Factors for Internalizing Symptoms.

    Science.gov (United States)

    Brock, Rebecca L; Lawrence, Erika

    2014-03-01

    Marital discord has a robust association with depression, yet it is rarely considered within broader etiological frameworks of psychopathology. Further, little is known about the particular aspects of relationships that have the greatest impact on psychopathology. The purpose of the present study was to test a novel conceptual framework including neuroticism, specific relationship processes (conflict management, partner support, emotional intimacy, and distribution of power and control), and stress as predictors of internalizing symptoms (depression and anxiety). Questionnaire and interview data were collected from 103 husbands and wives 5 times over the first 7 years of marriage. Results suggest that neuroticism (an expression of the underlying vulnerability for internalizing disorders) contributes to symptoms primarily through high levels of non-marital stress, an imbalance of power/control in one's marriage, and poor partner support for husbands, and through greater emotional disengagement for wives. Marital processes, neuroticism, and stress work together to significantly predict internalizing symptoms, demonstrating the need to routinely consider dyadic processes in etiological models of individual psychopathology. Specific recommendations for adapting and implementing couple interventions to prevent and treat individual psychopathology are discussed.

  13. Fabrication of Ni-Mn Microprobe Structure with Low Internal Stress and High Hardness by Employing DC Electrodeposition

    Directory of Open Access Journals (Sweden)

    Kuan-Hui Cheng

    2014-01-01

    Full Text Available Due to its widely tunable mechanical property and incompatibility with most solders, Ni-Mn alloy can become a viable candidate in the fabrication of testing probe for microelectronic devices. In this study, the electrodeposition of Ni-Mn alloy in nickel sulphamate electrolyte with the addition of manganese sulphate was investigated under direct current (DC power source. The effects of current density and Mn2+ concentration in the electrolyte on the coating composition, cathodic efficiency, microstructure and mechanical properties were explored. The results showed that the raise of the Mn2+ concentration in the electrolyte alone did not effectively increase the Mn content in the coating but reduce the cathodic efficiency. On the other hand, increasing the current density facilitated the codeposition of the Mn and rendered the crystallite from coarse columnar grain to the refined one. Thus, both hardness and internal stress of the coating increased. The fabrication of testing probes at 1 A/dm2 was shown to satisfy the high hardness, low internal stress, reasonable fatigue life, and nonsticking requirements for this microelectronic application.

  14. Determination of internal exposure doses of the personnel of uranium-mining company due to radon isotopes decay products

    International Nuclear Information System (INIS)

    Sevostyanov, V.N.

    2004-01-01

    This work carries out a determination of individual doses of internal exposure of the staff of the uranium-mining company in Kazakhstan due to radon decay products. The company extracts uranium by in-situ leaching. After leaching, uranium is sorbed from a solution in facilities where the staff is located. The state of three uranium mines was analyzed. The dose determination was conducted in tune with the proposed method by using integral alpha-tracking detectors to identify the content of 222 Rn and express appliances to identify the content of radio-active aerosols in air of the working area for determination the equilibrium coefficient. The measurements were performed within one year. The work produced the results in average annual values of radon and thoron decay products activity concentration and variation, equilibrium coefficient variation, and so-called expressive-to-integral value conversion factor. The obtained personnel's individual radiation doses due to radon exposure for this period lie within the range of < 1 mSv/year. (author)

  15. Parametric Assessment of Stress Development and Cracking in Internally Cured Restrained Mortars Experiencing Autogenous Deformations and Thermal Loading

    Directory of Open Access Journals (Sweden)

    Kambiz Raoufi

    2011-01-01

    Full Text Available A finite element model is used to examine how the properties of cementitious mortar are related to the stress development in the dual ring test. The results of this investigation are used to explain the thermal cracking behavior of mixtures containing prewetted lightweight aggregates (LWA by quantifying the contribution of several material properties individually. In addition to the beneficial effects of using the LWA as an internal curing agent to reduce the autogenous shrinkage of concrete, the LWA also helps to reduce the potential for thermal cracking due to a lower elastic modulus and increased stress relaxation. The rate of stress development, age of cracking, and magnitude of the temperature drop necessary to induce cracking in a dual ring specimen are dependent on a variety of factors, including the coefficient of thermal expansion of both the cementitious mortar and the restraining rings, elastic modulus of the mortar, creep effect of the mortar, and rate of thermal loading. Depending on the rate of cooling, cracking may or may not occur. The slowest rate of cooling (2.5∘C/h minimizes the effects of creep while cooling rates faster than 8∘C/h can produce a thermal gradient through the mortar cross-section that needs to be considered.

  16. Everyday hassles and uplifts among women on long-term sick-leave due to stress-related disorders.

    Science.gov (United States)

    Johansson, Gun; Eklund, Mona; Erlandsson, Lena-Karin

    2012-05-01

    A balance between different experiences of occupations in everyday life is important for well-being. The study aim was to describe hassles and uplifts in everyday occupations among women on long-term sick-leave due to stress-related disorders. The sample consisted of 77 women and experiences were collected by the THU-5 instrument. The statements were analysed using quantitative content analysis. Data were categorized into three domains of hassles concerning oneself, doings, and social and physical context. The same domains occurred among the uplifts. Hassles were mostly generated by disturbing people around the women and by their limited body functions. The women were uplifted by supportive social relationships and by performing relaxing and calming occupations. The study illuminates the strong need for social support among women on sick-leave, as well as their low level of energy, which was an obvious obstacle for performing occupations. It is suggested that, in order to increase well-being in the target group, the occupational therapist should meet their need for occupations that match their current level of energy. The challenge for the client is to avoid remaining in a pattern of low-demand occupations without exceeding her/his capacity and returning to an unhealthy pattern of occupations.

  17. Correlates and predictors of parenting stress among internationally adopting mothers: A longitudinal investigation.

    Science.gov (United States)

    Viana, Andres G; Welsh, Janet A

    2010-07-01

    This study examined correlates and predictors of parenting stress among internationally adopting (IA) mothers with the goal of expanding the knowledge base on the experiences of adoptive parents. One hundred and forty-three IA mothers completed pre-adoption (Time 0) and six months post-adoption (Time 1) surveys with questions regarding child-, parent-, and family-related characteristics. Mother reports of higher depression symptoms, higher expectations of child developmental and behavioral/emotional problems, and a greater number of children in the family at pre-adoption were significantly related to higher parenting stress six months post-adoption. In contrast, mother reports of higher expectations for child acceptance and higher perceived social support at pre-adoption were significantly related to lower parenting stress six months post-adoption. Higher maternal depression symptoms, higher expectations of child behavior/emotional problems, and a greater number of children in the family at pre-adoption together accounted for 22% of the variance in parenting stress six months post-adoption. Concurrent higher maternal depression symptoms and higher reports of child behavioral/emotional problems predicted higher parenting stress six months post-adoption over and above pre-adoption predictors, and accounted for an additional 33% of the variance. Results and directions for future research are discussed from a transactional perspective, with particular emphasis on the importance of pre-adoptive information for adoption research and practice.

  18. Joining U.S. NRC international round robin for weld residual stress analysis. Stress analysis and validation in PWSCC mitigation program

    International Nuclear Information System (INIS)

    Maekawa, Akira; Serizawa, Hisashi; Murakawa, Hidekazu

    2012-01-01

    It is necessary to establish properly reliable weld residual stress analysis methods for accurate crack initiation and growth assessment of primary water stress corrosion cracking (PWSCC), which may occur in nickel-based dissimilar metal welds in pressurized water reactors. The U.S. Nuclear Regulatory Commission conducted an international round robin for weld residual stress analysis to improve stress analysis methods and to examine the uncertainties involved in the calculated stress values. In this paper, the results from the authors' participation in the round robin were reported. In the round robin, the weld residual stress in a nickel-based dissimilar metal weld of a pressurizer surge nozzle mock-up was computed under various analysis conditions. Based on these residual stress analysis results, a welding simulation code currently being developed that uses the iterative substructure method was validated and affecting factors on the analysis results were identified. (author)

  19. On the calculation of internal forces in mechanically stressed polyatomic molecules

    International Nuclear Information System (INIS)

    Avdoshenko, Stanislav M.; Konda, Sai Sriharsha M.; Makarov, Dmitrii E.

    2014-01-01

    We discuss how to define and to compute internal forces in a molecule subjected to mechanical stress. Because of the inherently many-body character of intramolecular interactions, internal forces cannot be uniquely defined without specifying a set of internal coordinates used to describe the molecular structure. When such a set is comprised of 3N − 6 interactomic distances (N being the number of atoms) and includes the bond lengths of interest, we show that the associated forces, while satisfying the equation F = ∂V/∂R (where R is the bond length, F is the internal force in this bond, and V is the potential energy of the molecule), can be determined from the molecular geometry alone. We illustrate these ideas using several toy models ranging from small molecules to a graphene sheet and show that the magnitude of the internal force in a bond is not necessarily a good predictor of its strength in response to mechanical loading. At the same time, analysis of internal forces reveals interesting phenomena such as the force multiplication effect, where weak external forces may, e.g., be used to break strong bonds, and offers insight into the catch-bond phenomenon where chemical reactivity is suppressed through application of a force

  20. Hardening of particle/oil/water suspensions due to capillary bridges: Experimental yield stress and theoretical interpretation.

    Science.gov (United States)

    Danov, Krassimir D; Georgiev, Mihail T; Kralchevsky, Peter A; Radulova, Gergana M; Gurkov, Theodor D; Stoyanov, Simeon D; Pelan, Eddie G

    2018-01-01

    Suspensions of colloid particles possess the remarkable property to solidify upon the addition of minimal amount of a second liquid that preferentially wets the particles. The hardening is due to the formation of capillary bridges (pendular rings), which connect the particles. Here, we review works on the mechanical properties of such suspensions and related works on the capillary-bridge force, and present new rheological data for the weakly studied concentration range 30-55 vol% particles. The mechanical strength of the solidified capillary suspensions, characterized by the yield stress Y, is measured at the elastic limit for various volume fractions of the particles and the preferentially wetting liquid. A quantitative theoretical model is developed, which relates Y with the maximum of the capillary-bridge force, projected on the shear plane. A semi-empirical expression for the mean number of capillary bridges per particle is proposed. The model agrees very well with the experimental data and gives a quantitative description of the yield stress, which increases with the rise of interfacial tension and with the volume fractions of particles and capillary bridges, but decreases with the rise of particle radius and contact angle. The quantitative description of capillary force is based on the exact theory and numerical calculation of the capillary bridge profile at various bridge volumes and contact angles. An analytical formula for Y is also derived. The comparison of the theoretical and experimental strain at the elastic limit reveals that the fluidization of the capillary suspension takes place only in a deformation zone of thickness up to several hundred particle diameters, which is adjacent to the rheometer's mobile plate. The reported experimental results refer to water-continuous suspension with hydrophobic particles and oily capillary bridges. The comparison of data for bridges from soybean oil and hexadecane surprisingly indicate that the yield strength is

  1. The secondary stress analyses in the fuel pin cladding due to the swelling gradient across the wall thickness

    International Nuclear Information System (INIS)

    Uwaba, Tomoyuki; Ukai, Shigeharu

    2002-01-01

    Irradiation deformation analyses of FBR fuel cladding were made by using the finite element method. In these analyses the history of the stress occurred in the cladding was evaluated paying attention to the secondary stress induced by the swelling difference across the wall thickness. It was revealed that the difference of the swelling incubation dose in the direction of the thickness and the irradiation creep deformation play an important role in the history of the secondary stress. The effect of the stress-enhanced swelling was also analyzed in this study

  2. Predictors of suicidal behaviour in 36,304 individuals sickness absent due to stress-related mental disorders -- a Swedish register linkage cohort study

    DEFF Research Database (Denmark)

    Ishtiak-Ahmed, Kazi; Perski, Aleksander; Mittendorfer-Rutz, Ellenor

    2013-01-01

    BACKGROUND: Stress-related mental disorders (SRMD), which correspond to the diagnostic code F43 in the International Classification of Diseases, version 10, rank among the leading causes of sickness absence in several European countries. Despite the size of this health problem, research on risk...

  3. Stress Distribution in the Dissimilar Metal Butt Weld of Nuclear Reactor Piping due to the Simulation Technique for the Repair Welding

    International Nuclear Information System (INIS)

    Lee, Hweeseung; Huh, Namsu; Kim, Jinsu; Lee, Jinho

    2013-01-01

    During welding, the dissimilar metal butt welds of nuclear piping are typically subjected to repair welding in order to eliminate defects that are found during post-weld inspection. It has been found that the repair weld can significantly increase the tensile residual stress in the weldment, and therefore, accurate estimation of the weld residual stress due to repair weld, especially for dissimilar metal welds using Ni-based alloy 82/182 in nuclear components, is of great importance in order to assess susceptibility to primary water stress corrosion cracking. In the present study, the stress distributions of dissimilar metal butt welds in nuclear reactor piping subjected to repair weld were investigated based on detailed nonlinear finite element analyses. Particular emphasis was placed on the variation of the stress distribution in the dissimilar metal butt weld according to the finite element welding analysis sequence for the repair welding process

  4. Barotropic Eulerian residual circulation in the Gulf of California due to the M{sub 2} tide and wind stress

    Energy Technology Data Exchange (ETDEWEB)

    Argote, M. L.; Lavin, M. F.; Amador, A. [Departamento de Oceanografia Fisica, CICESE, Ensenada, Baja California (Mexico)

    1998-07-01

    A vertically integrated, non-linear numerical model in finite differences is used to analyze two forcing mechanisms of the mean barotropic circulation in the Gulf of California: topographic rectification due to tidal currents (M{sub 2}) and wind stress. Under tidal forcing the nonlinearities of the momentum equations induce unorganized strong tidal induced residual currents (u{sub e} > 5 cm s{sup -}1) in the channels between the islands, and along-isobath anticyclonic circulation in the Northern Gulf, with speeds u{sub 3} < 2.5 cm s{sup -}1 over the edge of Delfin Basin. These numerical results are in agreement with analytical results, which indicate that the tidal-induced currents are mostly due to the advective terms, and that continuity and the Coriolis term (but regulated by bottom friction) are responsible for the along-isobath flow. The quadratic bottom friction plays a role in generating mean currents only in the very shallow area off the Colorado River Delta. The effect of wind stress was modeled by imposing upon the running M{sub 2} model a constant surface stress ( r = 0.016 Pa), from the NW for winter conditions and from the SE for summer conditions. The wind-induced circulation was obtained by averaging over a tidal cycle and then subtracting the tidal residuals. The two wind directions produce almost identical circulation patterns, but with opposite directions. For the NW wind stress, the main features of the predicted circulation are: (a) In the Northern Gulf an anticyclonic circulation pattern, with the strongest currents (up to {approx} 10 cm s-1) following the bathymetry of the rim of Delfin Basin, Wagner Basin and the mainland coast off Bahia Adair and Bahia San Jorge. There is also a southward flow along the peninsula coast, from the Colorado River to Bahia San Luis Gonzaga. (b) In the Southern Gulf, there is a strong flow ({approx} 10 to 15 cm s{sup -}1) to the SE over the continental shelf along the mainland coast. A somewhat less well

  5. Growth recovery in newly arrived international adoptees in Italy: relation to parenting stress.

    Science.gov (United States)

    Canzi, Elena; Rosnati, Rosa; Miller, Laurie C

    2018-04-12

    Following initial adversities, most internationally adopted children arrive with significant growth delays. Post-placement recovery has been widely documented, but research about risk or protective factors is still limited. Even less is known about the relationship between growth recovery and the quality of the family environment. 28 children in 26 adoptive families were involved in this longitudinal study. A comprehensive evaluation (including anthropometry, cognitive assessment [using the Leiter International Performance Scale-Revised], and completion by both parents of the Parenting Stress Index - Short Form) was done at arrival of the child, and 1 year later. Results evidenced that on arrival nearly half of children had growth measurements in the normal range. All the children showed a significant recovery in height and weight at 6 and 12 months post-placement. Initial and follow up growth measurements correlated strongly. Growth recovery was related to the age of the child at adoption, the proportion of time the child had resided in institutional care, as well as parenting stress. Results suggested that the higher the parenting stress experienced the less improvements occurred in children: for mothers for height and weight, for fathers for all the growth indicators. Results suggested the critical importance of family factor in influencing children's growth recovery.

  6. Consensus statement update on posttraumatic stress disorder from the international consensus group on depression and anxiety.

    Science.gov (United States)

    Ballenger, James C; Davidson, Jonathan R T; Lecrubier, Yves; Nutt, David J; Marshall, Randall D; Nemeroff, Charles B; Shalev, Arieh Y; Yehuda, Rachel

    2004-01-01

    To provide an update to the "Consensus Statement on Posttraumatic Stress Disorder From the International Consensus Group on Depression and Anxiety" that was published in a supplement to The Journal of Clinical Psychiatry (2000) by presenting important developments in the field, the latest recommendations for patient care, and suggestions for future research. The 4 members of the International Consensus Group on Depression and Anxiety were James C. Ballenger (chair), Jonathan R. T. Davidson, Yves Lecrubier, and David J. Nutt. Other faculty who were invited by the chair were Randall D. Marshall, Charles B. Nemeroff, Arieh Y. Shalev, and Rachel Yehuda. The consensus statement is based on the 7 review articles in this supplement and the related scientific literature. Group meetings were held over a 2-day period. On day 1, the group discussed topics to be represented by the 7 review articles in this supplement, and the chair identified key issues for further debate. On day 2, the group discussed these issues to arrive at a consensus view. After the group meetings, the consensus statement was drafted by the chair and approved by all faculty. There have been advancements in the science and treatment of posttraumatic stress disorder. Attention to this disorder has increased with recent world events; however, continued efforts are needed to improve diagnosis, treatment, and prevention of posttraumatic stress disorder.

  7. An international comparison of occupational health guidelines for the management of mental disorders and stress-related psychological symptoms.

    Science.gov (United States)

    Joosen, Margot C W; Brouwers, Evelien P M; van Beurden, Karlijn M; Terluin, Berend; Ruotsalainen, Jani H; Woo, Jong-Min; Choi, Kyeong-Sook; Eguchi, Hisashi; Moriguchi, Jiro; van der Klink, Jac J L; van Weeghel, Jaap

    2015-05-01

    We compared available guidelines on the management of mental disorders and stress-related psychological symptoms in an occupational healthcare setting and determined their development and reporting quality. To identify eligible guidelines, we systematically searched National Guideline Clearinghouse, Guidelines International Network Library and PubMed. Members of the International Commission on Occupational Health (ICOH), were also consulted. Guidelines recommendations were compared and reporting quality was assessed using the AGREE II instrument. Of 2126 titles retrieved, 14 guidelines were included: 1 Japanese, 2 Finnish, 2 Korean, 2 British and 7 Dutch. Four guidelines were of high-reporting quality. Best described was the Scope and Purpose, and the poorest described were competing interests (Editorial independence) and barriers and facilitators for implementation (Applicability). Key recommendations were often difficult to identify. Most guidelines recommend employing an inventory of symptoms, diagnostic classification, performance problems and workplace factors. All guidelines recommend specific return-to-work interventions, and most agreed on psychological treatment and communication between involved stakeholders. Practice guidelines to address work disability due to mental disorders and stress-related symptoms are available in various countries around the world, however, these guidelines are difficult to find. To promote sharing, national guidelines should be accessible via established international databases. The quality of the guideline's developmental process varied considerably. To increase quality and applicability, guideline developers should adopt a common structure for the development and reporting of their guidelines, for example Appraisal of Guidelines for Research and Evaluation (AGREE) criteria. Owing to differences in social systems, developers can learn from each other through reviews of this kind. Published by the BMJ Publishing Group Limited

  8. Improved tolerance to drought stress after anthesis due to priming before anthesis in wheat (Triticum aestivum L.) var. Vinjett

    DEFF Research Database (Denmark)

    Wang, Xiao; Vignjevic, Marija; Jiang, Dong

    2014-01-01

    Drought stress occurring during the reproductive growth stage leads to considerable reductions in crop production and has become an important limiting factor for food security globally. In order to explore the possible role of drought priming (pre-exposure of the plants to mild drought stress...

  9. Copper induces hepatocyte injury due to the endoplasmic reticulum stress in cultured cells and patients with Wilson disease

    International Nuclear Information System (INIS)

    Oe, Shinji; Miyagawa, Koichiro; Honma, Yuichi; Harada, Masaru

    2016-01-01

    Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.

  10. Copper induces hepatocyte injury due to the endoplasmic reticulum stress in cultured cells and patients with Wilson disease

    Energy Technology Data Exchange (ETDEWEB)

    Oe, Shinji, E-mail: ooes@med.uoeh-u.ac.jp; Miyagawa, Koichiro, E-mail: koichiro@med.uoeh-u.ac.jp; Honma, Yuichi, E-mail: y-homma@med.uoeh-u.ac.jp; Harada, Masaru, E-mail: msrharada@med.uoeh-u.ac.jp

    2016-09-10

    Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.

  11. Reproductive function in the sons of women who experienced stress due to bereavement before and during pregnancy

    DEFF Research Database (Denmark)

    Plana-Ripoll, Oleguer; Li, Jiong; Kesmodel, Ulrik Schiøler

    2017-01-01

    OBJECTIVE: To estimate the association between prenatal exposure to maternal stress and reproductive disorders in Danish men, where prenatal stress exposure was defined as the mother's loss of a close relative during pregnancy or in the 12 months before conception. DESIGN: Population-based cohort...

  12. Stress on Cold Mass Due to the Supporting System of the CMS Coil in the Vacuum Tank

    CERN Document Server

    Farinon, S

    2000-01-01

    This report contains a verification analysis of the stress on cold mass coming from the supporting system of the CMS coil in the vacuum tank. The need to carry out this analysis is related to the high mechanical requirements for $9 Al-alloy mandrels (218 MPa yield at cryogenic temperature), demanding accurate analysis of the impact of supporting system on cylinder stress.

  13. The internal stress measurement the neutron diffraction bring happiness to your country

    Energy Technology Data Exchange (ETDEWEB)

    Minakawa, Nobuaki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The neutron was discovered by Chadwick in 1932. The first reactor was constructed by the USA in 1942. After that, the research and development of reactors advanced. Numbers of reactors were constructed in Europe and in the US. The researches, which use the neutron, were performed actively and excellent results were obtained in wide fields. The penetrating power of the neutron and the neutron diffraction method began to attract attention for the application to the internal stress measurement, too. In Japan, the neutron diffractometer for the residual stress measurement exclusive was installed in the JRR-3M research reactor of JAERI in 1992, and the research was started. At present, we are using it for the stress measurements of the parts of aircrafts, railways, automobiles, buildings, machines, home electronics products and so on including nuclear reactors. Reliable science must be introduced in order to support safety and long life operation and to supply them at reasonable cost. Among the various scientific probes to find faults in materials, diffraction technique is used to measure the strain distribution in materials by observing the local changes of the distance between crystallographic planes and the stress distribution is computed to improve manufacturing processes. It is only neutron diffraction that can be used to measure the strain inside the materials. Here, I present an overview of the utilization of neutron scattering research for the industrial uses and the history of the neutron scattering research in JAERI briefly. (J.P.N.)

  14. A new coal-permeability model: Internal swelling stress and fracture-matrix interaction

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.H.; Rutqvist, J.

    2009-10-01

    We have developed a new coal-permeability model for uniaxial strain and constant confining stress conditions. The model is unique in that it explicitly considers fracture-matrix interaction during coal deformation processes and is based on a newly proposed internal-swelling stress concept. This concept is used to account for the impact of matrix swelling (or shrinkage) on fracture-aperture changes resulting from partial separation of matrix blocks by fractures that do not completely cut through the whole matrix. The proposed permeability model is evaluated with data from three Valencia Canyon coalbed wells in the San Juan Basin, where increased permeability has been observed during CH{sub 4} gas production, as well as with published data from laboratory tests. Model results are generally in good agreement with observed permeability changes. The importance of fracture-matrix interaction in determining coal permeability, demonstrated in this work using relatively simple stress conditions, underscores the need for a dual-continuum (fracture and matrix) mechanical approach to rigorously capture coal-deformation processes under complex stress conditions, as well as the coupled flow and transport processes in coal seams.

  15. Initial Characterization of Internal Medicine Resident Resilience and Association with Stress and Burnout

    Directory of Open Access Journals (Sweden)

    Amber-Nicole Bird

    2016-01-01

    Full Text Available Introduction. Burnout is prevalent in medical trainees. Little data exists on resident resilience. Methods. Anonymous surveys were provided to a convenience sample of internal medicine residents. Resilience was assessed using the Connor-Davidson resilience scale. Responses were categorized into low (<70, intermediate (70–79, and high (80–100 resilience. Results. 77 residents from six institutions completed surveys. 26% of residents had high resilience, 43% intermediate, and 31% low. The mean resilience score was 73.6±9.6 and lower than the general population (mean 80.4±12.5, p<0.001. Trainees with high resilience were more likely to never have stress interfere with their relationships outside of work (high: 40%; low: 0%; p<0.001. High resilience residents were more likely to have the skills to manage stress and burnout (high: 80%; low: 46%; p=0.02 and less likely to feel inferior to peers (high: 20.0%; low: 70.8%; p<0.001. There was a trend towards those with high resilience reporting less burnout (high: 40.0%; intermediate: 27%; low: 16.7%; p=0.08. Only 60% report a program outlet to discuss burnout. Conclusions. There is a wide range of resilience among IM residents and scores were lower than the general population. Low resilience is associated with more stress interfering with relationships, feeling inferior to peers, and fewer skills to manage stress and burnout.

  16. The internal stress measurement the neutron diffraction will bring happiness to your country

    International Nuclear Information System (INIS)

    Minakawa, Nobuaki

    2003-01-01

    The neutron was discovered by Chadwick in 1932. The first reactor was constructed by the USA in 1942. After that, the research and development of reactors advanced. Numbers of reactors were constructed in Europe and in the US. The researches, which use the neutron, were performed actively and excellent results were obtained in wide fields. The penetrating power of the neutron and the neutron diffraction method began to attract attention for the application to the internal stress measurement, too. In Japan, the neutron diffractometer for the residual stress measurement exclusive was installed in the JRR-3M research reactor of JAERI in 1992, and the research was started. At present, we are using it for the stress measurements of the parts of air crafts, railways, automobiles, buildings, machines, home electronics products and so on including nuclear reactors. Reliable science must be introduced in order to support safety and long life operation and to supply them at reasonable cost. Among the various scientific probes to find faults in materials, diffraction technique is used to measure the strain distribution in materials by observing the local changes of the distance between crystallographic planes and the stress distribution is computed to improve manufacturing processes. It is only neutron diffraction that can be used to measure the strain inside the materials. Here, I present an overview of the utilization of neutron scattering research for the industrial uses and the history of the neutron scattering research in JAERI briefly. (J.P.N.)

  17. Effects of Abiotic and Biotic Stresses on the Internalization and Dissemination of Human Norovirus Surrogates in Growing Romaine Lettuce.

    Science.gov (United States)

    DiCaprio, Erin; Purgianto, Anastasia; Li, Jianrong

    2015-07-01

    Human norovirus (NoV) is the major causative agent of fresh-produce-related outbreaks of gastroenteritis; however, the ecology and persistence of human NoV in produce systems are poorly understood. In this study, the effects of abiotic and biotic stresses on the internalization and dissemination of two human NoV surrogates (murine norovirus 1 [MNV-1] and Tulane virus [TV]) in romaine lettuce were determined. To induce abiotic stress, romaine lettuce was grown under drought and flood conditions that mimic extreme weather events, followed by inoculation of soil with MNV-1 or TV. Independently, lettuce plants were infected with lettuce mosaic virus (LMV) to induce biotic stress, followed by inoculation with TV. Plants were grown for 14 days, and viral titers in harvested tissues were determined by plaque assays. It was found that drought stress significantly decreased the rates of both MNV-1 and TV internalization and dissemination. In contrast, neither flood stress nor biotic stress significantly impacted viral internalization or dissemination. Additionally, the rates of TV internalization and dissemination in soil-grown lettuce were significantly higher than those for MNV-1. Collectively, these results demonstrated that (i) human NoV surrogates can be internalized via roots and disseminated to shoots and leaves of romaine lettuce grown in soil, (ii) abiotic stress (drought) but not biotic stress (LMV infection) affects the rates of viral internalization and dissemination, and (iii) the type of virus affects the efficiency of internalization and dissemination. This study also highlights the need to develop effective measures to eliminate internalized viruses in fresh produce. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  18. Analysis of neutron diffraction peak broadening caused by internal stresses in composite materials

    International Nuclear Information System (INIS)

    Todd, R.I.; Borsa, C.; Derby, B.

    1994-01-01

    Neutron diffraction is an essential tool in the study of internal stresses in composite materials. In most work only the peak shifts caused by the related elastic strains are considered, but other valuable information exists in the form of peak shape changes. The conditions under which the pure diffraction profile of the composite (i.e. the profile when all sources of broadening not caused by the residual stresses are removed) represents the probability distribution of the peak shifts corresponding to the strains are examined. It is shown that in these conditions, the pure diffraction profile has no attributes of particle size broadening (and vice versa), thereby providing a test for the validity of results interpreted in this way. The experimental derivation of measured strain distributions in Al 2 O 3 /SiCp composites using neutron diffraction is described. No apparent particle size broadening was detected, demonstrating the validity of the results, which also satisfied other tests for consistency

  19. The Effect of Perfectionism and Acculturative Stress on Levels of Depression Experienced by East Asian International Students

    Science.gov (United States)

    Hamamura, Toshitaka; Laird, Philip G.

    2014-01-01

    This study examined relationships among acculturative stress, grade point average satisfaction, maladaptive perfectionism, and depression in 52 East Asian international students and 126 North American students. Results indicated that a combined effect of perfectionism and acculturative stress accounted for more than 30% of the variance related to…

  20. Constraints on Stress Components at the Internal Singular Point of an Elastic Compound Structure

    Science.gov (United States)

    Pestrenin, V. M.; Pestrenina, I. V.

    2017-03-01

    The classical analytical and numerical methods for investigating the stress-strain state (SSS) in the vicinity of a singular point consider the point as a mathematical one (having no linear dimensions). The reliability of the solution obtained by such methods is valid only outside a small vicinity of the singular point, because the macroscopic equations become incorrect and microscopic ones have to be used to describe the SSS in this vicinity. Also, it is impossible to set constraint or to formulate solutions in stress-strain terms for a mathematical point. These problems do not arise if the singular point is identified with the representative volume of material of the structure studied. In authors' opinion, this approach is consistent with the postulates of continuum mechanics. In this case, the formulation of constraints at a singular point and their investigation becomes an independent problem of mechanics for bodies with singularities. This method was used to explore constraints at an internal singular point (representative volume) of a compound wedge and a compound rib. It is shown that, in addition to the constraints given in the classical approach, there are also constraints depending on the macroscopic parameters of constituent materials. These constraints turn the problems of deformable bodies with an internal singular point into nonclassical ones. Combinations of material parameters determine the number of additional constraints and the critical stress state at the singular point. Results of this research can be used in the mechanics of composite materials and fracture mechanics and in studying stress concentrations in composite structural elements.

  1. PREFACE: 7th International Conference on Modern Practice in Stress and Vibration Analysis

    Science.gov (United States)

    Dulieu-Barton, J. M.

    2009-07-01

    The proceedings contain the papers presented at the 7th International Conference on Modern Practice in Stress and Vibration Analysis. The collection of papers represents the range of activities that are carried out to understand the functionality of engineering systems and structures through stress/strain based evaluation and dynamic response. The scope is broad and covers theoretical studies, modelling and experimental evaluations. Many of the papers cover integration techniques and approaches to better understanding of system performance and failure. All of the papers have been peer reviewed by at least two experts and represent the state of the art of research in this area. The conference is the seventh in the series, following on from previous conferences in Bath, Glasgow, Nottingham, Dublin, Sheffield and Liverpool. Although based in the British Isles the conference has a truly international flavour with offerings from 22 countries. The conference is organised by the Institute of Physics Applied Mechanics Group (formerly the Stress and Vibration Group). It incorporates activities associated with the British Society for Strain Measurement including the Measurements Lecture, the EMex Exhibition and the Young Stress Analyst Competition. The organising committee is grateful for the support of all of the authors, the scientific committee and keynote speakers who played a significant role in the review process, to John Edwards who was instrumental in managing the paper review and submission process, Dawn Stewart and Claire Garland of the Institute of Physics for organising the conference, social programme and registration and Biana Gale of the British Society for Strain Measurement for organising the Exhibition. The organising committee is also grateful to the sponsors of the conference for their kind support and to the co-sponsors for distributing information on the conference. Professor Janice M Dulieu-Barton Professor of Experimental Mechanics University of

  2. MRI Shows that Exhaustion Syndrome Due to Chronic Occupational Stress is Associated with Partially Reversible Cerebral Changes.

    Science.gov (United States)

    Savic, I; Perski, A; Osika, W

    2018-03-01

    The present study investigates the cerebral effects of chronic occupational stress and its possible reversibility. Forty-eight patients with occupational exhaustion syndrome (29 women) and 80 controls (47 women) underwent structural magnetic resonance imaging (MRI) and neuropsychological testing. Forty-four participants (25 patients, 19 controls) also completed a second MRI scan after 1-2 years. Only patients received cognitive therapy. The stressed group at intake had reduced thickness in the right prefrontal cortex (PFC) and left superior temporal gyrus (STG), enlarged amygdala volumes, and reduced caudate volumes. Except for the caudate volume, these abnormalities were more pronounced in females. They were all related to perceived stress, which was similar for both genders. Thickness of the PFC also correlated with an impaired ability to down-modulate negative emotions. Thinning of PFC and reduction of caudate volume normalized in the follow-up. The amygdala enlargement and the left STG thinning remained. Longitudinal changes were not detected among controls. Chronic occupational stress was associated with partially reversible structural abnormalities in key regions for stress processing. These changes were dynamically correlated with the degree of perceived stress, highlighting a possible causal link. They seem more pronounced in women, and could be a substrate for an increased cerebral vulnerability to stress-related psychiatric disorders. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Random regression models to account for the effect of genotype by environment interaction due to heat stress on the milk yield of Holstein cows under tropical conditions.

    Science.gov (United States)

    Santana, Mário L; Bignardi, Annaiza Braga; Pereira, Rodrigo Junqueira; Menéndez-Buxadera, Alberto; El Faro, Lenira

    2016-02-01

    The present study had the following objectives: to compare random regression models (RRM) considering the time-dependent (days in milk, DIM) and/or temperature × humidity-dependent (THI) covariate for genetic evaluation; to identify the effect of genotype by environment interaction (G×E) due to heat stress on milk yield; and to quantify the loss of milk yield due to heat stress across lactation of cows under tropical conditions. A total of 937,771 test-day records from 3603 first lactations of Brazilian Holstein cows obtained between 2007 and 2013 were analyzed. An important reduction in milk yield due to heat stress was observed for THI values above 66 (-0.23 kg/day/THI). Three phases of milk yield loss were identified during lactation, the most damaging one at the end of lactation (-0.27 kg/day/THI). Using the most complex RRM, the additive genetic variance could be altered simultaneously as a function of both DIM and THI values. This model could be recommended for the genetic evaluation taking into account the effect of G×E. The response to selection in the comfort zone (THI ≤ 66) is expected to be higher than that obtained in the heat stress zone (THI > 66) of the animals. The genetic correlations between milk yield in the comfort and heat stress zones were less than unity at opposite extremes of the environmental gradient. Thus, the best animals for milk yield in the comfort zone are not necessarily the best in the zone of heat stress and, therefore, G×E due to heat stress should not be neglected in the genetic evaluation.

  4. Residual stress relaxation due to fretting fatigue in shot peened surfaces of Ti-6Al-4V

    International Nuclear Information System (INIS)

    Martinez, S.A.; Blodgett, M.P.; Mall, S.; Sathish, S.; Namjoshi, S.

    2003-01-01

    Fretting fatigue occurs at locations where the materials are sliding against each other under load. In order to enhance the fatigue life under fretting conditions the surface of the component is shot peened. In general, the shot peening process produces a compressive stress on the surface of the material, thereby increasing the resistance of the material to crack initiation. This paper presents the relaxation of residual stress caused during fretting fatigue. X-ray diffraction has been utilized as the method to measure residual stress in fretting fatigued samples of Ti-6Al-4V

  5. FLANGE-ORNL, Flanged Pipe Joint Stress Analysis, Internal Pressure, Moment Loads, Temperature

    International Nuclear Information System (INIS)

    Rodabaugh, E.C.; Moore, S.E.

    1979-01-01

    1 - Description of problem or function: FLANGE-ORNL calculates appropriate loads, stresses, and displacements for the flanges, bolts, and gaskets that comprise a flanged piping joint for internal pressure or moment loading on the pipe, temperature difference between the flange hub and ring, and variations in bolt load that result from pressure, hub-ring temperature gradient and/or bolt-ring temperature differences. Flanges considered may be tapered-hub, straight or blind. 2 - Method of solution: The solution is based on discontinuity analysis and the theory of plates and shells

  6. β-cell dysfunction due to increased ER stress in a stem cell model of Wolfram syndrome.

    Science.gov (United States)

    Shang, Linshan; Hua, Haiqing; Foo, Kylie; Martinez, Hector; Watanabe, Kazuhisa; Zimmer, Matthew; Kahler, David J; Freeby, Matthew; Chung, Wendy; LeDuc, Charles; Goland, Robin; Leibel, Rudolph L; Egli, Dieter

    2014-03-01

    Wolfram syndrome is an autosomal recessive disorder caused by mutations in WFS1 and is characterized by insulin-dependent diabetes mellitus, optic atrophy, and deafness. To investigate the cause of β-cell failure, we used induced pluripotent stem cells to create insulin-producing cells from individuals with Wolfram syndrome. WFS1-deficient β-cells showed increased levels of endoplasmic reticulum (ER) stress molecules and decreased insulin content. Upon exposure to experimental ER stress, Wolfram β-cells showed impaired insulin processing and failed to increase insulin secretion in response to glucose and other secretagogues. Importantly, 4-phenyl butyric acid, a chemical protein folding and trafficking chaperone, restored normal insulin synthesis and the ability to upregulate insulin secretion. These studies show that ER stress plays a central role in β-cell failure in Wolfram syndrome and indicate that chemical chaperones might have therapeutic relevance under conditions of ER stress in Wolfram syndrome and other forms of diabetes.

  7. [Medication reconciliation: an innovative experience in an internal medicine unit to decrease errors due to inacurrate medication histories].

    Science.gov (United States)

    Pérennes, Maud; Carde, Axel; Nicolas, Xavier; Dolz, Manuel; Bihannic, René; Grimont, Pauline; Chapot, Thierry; Granier, Hervé

    2012-03-01

    An inaccurate medication history may prevent the discovery of a pre-admission iatrogenic event or lead to interrupted drug therapy during hospitalization. Medication reconciliation is a process that ensures the transfer of medication information at admission to the hospital. The aims of this prospective study were to evaluate the interest in clinical practice of this concept and the resources needed for its implementation. We chose to include patients aged 65 years or over admitted in the internal medicine unit between June and October 2010. We obtained an accurate list of each patient's home medications. This list was then compared with medication orders. All medication variances were classified as intended or unintended. An internist and a pharmacist classified the clinical importance of each unintended variance. Sixty-one patients (mean age: 78 ± 7.4 years) were included in our study. We identified 38 unintended discrepancies. The average number of unintended discrepancies was 0.62 per patient. Twenty-five patients (41%) had one or more unintended discrepancies at admission. The contact with the community pharmacist permitted us to identify 21 (55%) unintended discrepancies. The most common errors were the omission of a regularly used medication (76%) and an incorrect dosage (16%). Our intervention resulted in order changes by the physician for 30 (79%) unintended discrepancies. Fifty percent of the unintended variances were judged by the internist and 76% by the pharmacist to be clinically significant. The admission to the hospital is a critical transition point for the continuity of care in medication management. Medication reconciliation can identify and resolve errors due to inaccurate medication histories. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  8. Reduced coupling of oxidative phosphorylation in vivo precedes electron transport chain defects due to mild oxidative stress in mice.

    Directory of Open Access Journals (Sweden)

    Michael P Siegel

    Full Text Available Oxidative stress and mitochondrial function are at the core of many degenerative conditions. However, the interaction between oxidative stress and in vivo mitochondrial function is unclear. We used both pharmacological (2 week paraquat (PQ treatment of wild type mice and transgenic (mice lacking Cu, Zn-superoxide dismutase (SOD1(-/- models to test the effect of oxidative stress on in vivo mitochondrial function in skeletal muscle. Magnetic resonance and optical spectroscopy were used to measure mitochondrial ATP and oxygen fluxes and cell energetic state. In both models of oxidative stress, coupling of oxidative phosphorylation was significantly lower (lower P/O at rest in vivo in skeletal muscle and was dose-dependent in the PQ model. Despite this reduction in efficiency, in vivo mitochondrial phosphorylation capacity (ATPmax was maintained in both models, and ex vivo mitochondrial respiration in permeabilized muscle fibers was unchanged following PQ treatment. In association with the reduced P/O, PQ treatment led to a dose-dependent reduction in PCr/ATP ratio and increased phosphorylation of AMPK. These results indicate that oxidative stress uncouples oxidative phosphorylation in vivo and results in energetic stress in the absence of defects in the mitochondrial electron transport chain.

  9. The Role of Attachment, Travel Experiences and English Proficiency in International Students' Acculturative Stress and Depressive Symptoms

    Science.gov (United States)

    Smiljanic, Iskra

    2017-01-01

    This study examined the relationship between attachment, travel experiences, and English proficiency and international students' acculturative stress and depressive symptoms. A total of 91 graduate international students completed online surveys. Pearson correlations showed that both attachment anxiety and avoidance were positively correlated with…

  10. Relationship between Religious Orientation (Internal-External) With Methods of Overcoming Stress in Students of Islamic Azad University of Abhar

    Science.gov (United States)

    Jafari, Alireza

    2011-01-01

    This study explored the relationship between religious orientation (internal-external) and the ways of coping stress (problem-based and emotion-based) in the students of IAU (Islamic Azad University), Abhar Branch. Religion with internal origin is comprehensive and has well-organized principles. However, religion with external origin is a device…

  11. Work-focused cognitive behavioral intervention for psychological complaints in patients on sick leave due to work-related stress: Results from a randomized controlled trial.

    Science.gov (United States)

    Dalgaard, Vita Ligaya; Andersen, Lars Peter Sønderbo; Andersen, Johan Hviid; Willert, Morten Vejs; Carstensen, Ole; Glasscock, David John

    2017-08-22

    Work-related stress is a global problem with negative implications for individuals and society. The purpose of the current study was to evaluate a stress management intervention for patients on sick leave due to work-related stress complaints using a three-armed randomized controlled design. Participants were patients referred from three municipalities to the regional Department of Occupational Medicine. Inclusion criteria were: 1) sick leave due to work-related stress complaints, 2) a diagnosis of adjustment disorder or reactions to severe stress (ICD 10 code: F43,2 - F 43,9 not PTSD) or mild depressive episode (F 32.0). Through a double randomization procedure patients (n = 163) were randomized to either an intervention group (n = 58), a 'control group A' receiving a clinical examination (n = 56), or 'control group B' (n = 49) receiving no offers at the department. The intervention comprised six sessions of individual cognitive behavioral therapy and the offer of a small workplace intervention. Questionnaire data were analyzed with multivariate repeated measurements analysis. Primary outcomes assessed were perceived stress and general mental health. Secondary outcomes were sleep quality and cognitive failures. Follow-up was at four and 10 months after baseline. Complaints were significantly reduced in all groups over time. No group effects were observed between the intervention group and control group A that was clinically assessed. Significant group effects were found for perceived stress and memory when comparing the intervention group to group B, but most likely not due to an intervention effect. Psychological complaints improved substantially over time in all groups, but there was no significant treatment effect on any outcomes when the intervention group was compared to control group A that received a clinical assessment. ISRCTN ISRCTN91404229. Registered 03 August 2012 (retrospectively registered).

  12. Worsening of Heat Stress Due To Global Warming in South Korea Based on Multi-RCM Ensemble Projections

    Science.gov (United States)

    Im, Eun-Soon; Choi, Yeon-Woo; Ahn, Joong-Bae

    2017-11-01

    This study assesses the future changes in summer (June-July-August; JJA) heat stress over South Korea under global warming. To better resolve the region-specific changes in terms of geographical patterns and severity of heat stress in the Korean peninsula, four regional climate models (RCMs) are used for dynamical downscaling of Hadley Centre Global Environmental Model version 2—Atmosphere and Ocean global projections forced by two Representative Concentration Pathway (RCP4.5 and RCP8.5) scenarios. Dynamically downscaled simulations (horizontal resolution of 12.5 km and output interval of 3 h) facilitate in-depth analysis of diurnal variation and extremes over South Korea, as well as focusing on the particular location, Daegu, that is characterized by high vulnerability to rising temperature. Both maximum temperature and heat stress indices such as wet bulb globe temperature and apparent temperature, which include the effect of humidity, are examined in order to comprehensively interpret the behaviors of heat stress in response to anthropogenic climate change. Ensemble projections reveal robust patterns of temperature and resultant humidity increases that are roughly constrained by the approximate 7%/K increase in the moisture holding capacity. The changes in temperature and humidity are directly transmitted to the heat stress indices, showing a significant increase. The heat stress is exacerbated in a differentiated way, with more intensification in diurnal variation at nighttime and in regional variation at low-elevation basins. Both RCP4.5 and RCP8.5 scenarios project the statistical likelihood of a notable increase of extreme heat stress indices, much stronger and more extended heat waves, and the emergence of a long period of consecutive tropical nights.

  13. Hypoxic stress induces, but cannot sustain trophoblast stem cell differentiation to labyrinthine placenta due to mitochondrial insufficiency

    Directory of Open Access Journals (Sweden)

    Yufen Xie

    2014-11-01

    Full Text Available Dysfunctional stem cell differentiation into placental lineages is associated with gestational diseases. Of the differentiated lineages available to trophoblast stem cells (TSC, elevated O2 and mitochondrial function are necessary to placental lineages at the maternal–placental surface and important in the etiology of preeclampsia. TSC lineage imbalance leads to embryonic failure during uterine implantation. Stress at implantation exacerbates stem cell depletion by decreasing proliferation and increasing differentiation. In an implantation site O2 is normally ~2%. In culture, exposure to 2% O2 and fibroblast growth factor 4 (FGF4 enabled the highest mouse TSC multipotency and proliferation. In contrast, hypoxic stress (0.5% O2 initiated the most TSC differentiation after 24 h despite exposure to FGF4. However, hypoxic stress supported differentiation poorly after 4–7 days, despite FGF4 removal. At all tested O2 levels, FGF4 maintained Warburg metabolism; mitochondrial inactivity and aerobic glycolysis. However, hypoxic stress suppressed mitochondrial membrane potential and maintained low mitochondrial cytochrome c oxidase (oxidative phosphorylation/OxPhos, and high pyruvate kinase M2 (glycolysis despite FGF4 removal. Inhibiting OxPhos inhibited optimum differentiation at 20% O2. Moreover, adding differentiation-inducing hyperosmolar stress failed to induce differentiation during hypoxia. Thus, differentiation depended on OxPhos at 20% O2; hypoxic and hyperosmolar stresses did not induce differentiation at 0.5% O2. Hypoxia-limited differentiation and mitochondrial inhibition and activation suggest that differentiation into two lineages of the labyrinthine placenta requires O2 > 0.5–2% and mitochondrial function. Stress-activated protein kinase increases an early lineage and suppresses later lineages in proportion to the deviation from optimal O2 for multipotency, thus it is the first enzyme reported to prioritize differentiation.

  14. Quality of life among post-menopausal women due to oxidative stress boosted by dysthymia and anxiety.

    Science.gov (United States)

    Sánchez-Rodríguez, Martha A; Castrejón-Delgado, Lizett; Zacarías-Flores, Mariano; Arronte-Rosales, Alicia; Mendoza-Núñez, Víctor Manuel

    2017-01-03

    Menopause is the onset of aging in women. During this process, some women experience physical changes that may impact upon their psychological and social status, also affecting their quality of life. Furthermore, several psychological changes following menopause have been shown to act as pro-oxidant, but the association between the psychological status that modify the quality of life and oxidative stress in postmenopausal women is still unclear. The aim of this study was to determinate the relationship between oxidative stress with psychological disturbances, low self-esteem, depressive mood and anxiety, and quality of life in the postmenopausal women. We carried out a cross-sectional study with101 premenopausal and 101 postmenopausal women from Mexico City. As markers of oxidative stress we measured plasma lipoperoxide levels, erythrocyte superoxide dismutase and glutathione peroxidase activities, and total antioxidant status. We calculate a stress score as global oxidative stress status, with cut-off values for each parameter; this score range from 0 to 6, representing the severity of markers modifications. All the women were rated using the Coopersmith Self-Esteem Inventory, the Zung Self-Rating Anxiety and the Zung Self-Rating Depression Scales, and the WHO Quality of Life-brief. The postmenopausal women with low quality of life in the WHO Quality of Life-brief and their subscales had higher stress score compared with premenopausal women with high quality of life (p Life-brief scores (r = -0.266, p Life-brief, after adjusted for pro-oxidant factors. Zung Self-Rating Anxiety and Zung Self-Rating Depression Scales scores also contribute to increase lipoperoxides levels, but not significant. Our findings suggest that oxidative stress is increased in postmenopausal women with psychological disturbances and low quality of life.

  15. Associations among mothers' representations of their relationship with their toddlers, maternal parenting stress, and toddlers' internalizing and externalizing behaviors.

    Science.gov (United States)

    Sher-Censor, Efrat; Shulman, Cory; Cohen, Esther

    2018-02-01

    This study examined the array of associations among the emotional valence and the coherence of mothers' representations of their relationship with their toddlers, mothers' reported parenting stress, and toddlers' internalizing and externalizing behaviors. To evaluate maternal representations, 55 mothers were interviewed using the Five Minute Speech Sample procedure (FMSS; Magaña et al., 1986), which was coded for criticism and positive comments (Magaňa-Amato, 1993), as well as coherence (Sher-Censor & Yates, 2015). Mothers also completed the Parenting Stress Index - Short Form (PSI; Abidin, 1997) to evaluate their parenting stress and the Child Behavior Checklist (CBCL/1.5-5; Achenbach & Rescorla, 2000) to assess their toddlers' internalizing and externalizing behaviors. Results indicated that parenting stress was associated with maternal criticism and fewer positive comments in the FMSS, but not with the coherence of mothers' FMSS. Parenting stress, criticism, and lower coherence in the FMSS were associated with maternal reports of externalizing behaviors. Only parenting stress and lower coherence in the FMSS were related to mothers' reports of internalizing behaviors of the child. Thus, the emotional valence and the coherence of mothers' representations of their relationship with their child and parenting stress may each constitute a distinct aspect of parenting and contribute to the understanding of individual differences in toddlers' internalizing and externalizing behaviors. Implications for research and practice with families of toddlers are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Stress

    Science.gov (United States)

    ... can be life-saving. But chronic stress can cause both physical and mental harm. There are at least three different types of stress: Routine stress related to the pressures of work, family, and other daily responsibilities Stress brought about ...

  17. The Interactive Effects of Stressful Family Life Events and Cortisol Reactivity on Adolescent Externalizing and Internalizing Behaviors

    Science.gov (United States)

    Steeger, Christine M.; Cook, Emily C.; Connell, Christian M.

    2016-01-01

    This study investigated the associations between stressful family life events and adolescent externalizing and internalizing behaviors, and the interactive effects of family life events and cortisol reactivity on problem behaviors. In a sample of 100 mothers and their adolescents (M age = 15.09; SD age = 0.98; 68% girls), adolescent cortisol reactivity was measured in response to a mother-adolescent conflict interaction task designed to elicit a stress response. Mothers reported on measures of family life events and adolescent problem behaviors. Results indicated that a heightened adolescent cortisol response moderated the relations between stressful family life events and both externalizing and internalizing behaviors. Results support context-dependent theoretical models, suggesting that for adolescents with higher cortisol reactivity (compared to those with lower cortisol reactivity), higher levels of stressful family life events were associated with greater problem behaviors, whereas lower levels of stressful family life events were related to fewer problem behaviors. PMID:26961703

  18. Spectroscopic, microscopic, and internal stress analysis in cadmium telluride grown by close-space sublimation

    International Nuclear Information System (INIS)

    Manciu, Felicia S.; Salazar, Jessica G.; Diaz, Aryzbe; Quinones, Stella A.

    2015-01-01

    High quality materials with excellent ordered structure are needed for developing photovoltaic and infrared devices. With this end in mind, the results of our research prove the importance of a detailed, comprehensive spectroscopic and microscopic analysis in assessing cadmium telluride (CdTe) characteristics. The goal of this work is to examine not only material crystallinity and morphology, but also induced stress in the deposit material. A uniform, selective growth of polycrystalline CdTe by close-space sublimation on patterned Si(111) and Si(211) substrates is demonstrated by scanning electron microscopy images. Besides good crystallinity of the samples, as revealed by both Raman scattering and Fourier transform infrared absorption investigations, the far-infrared transmission data also show the presence of surface optical phonon modes, which is direct evidence of confinement in such a material. The qualitative identification of the induced stress was achieved by performing confocal Raman mapping microscopy on sample surfaces and by monitoring the existence of the rock-salt and zinc-blende structural phases of CdTe, which were associated with strained and unstrained morphologies, respectively. Although the induced stress in the material is still largely due to the high lattice mismatch between CdTe and the Si substrate, the current results provide a direct visualization of its partial release through the relaxation effect at crystallite boundaries and of preferential growth directions of less strain. Our study, thus offers significant value for improvement of material properties, by targeting the needed adjustments in the growth processes. - Highlights: • Assessing the characteristics of CdTe deposited on patterned Si substrates • Proving the utility of confocal Raman microscopy in monitoring the induced stress • Confirming the partial stress release through the grain boundary relaxation effect • Demonstrating the phonon confinement effect in low

  19. Carbon emission offsets for aviation-generated emissions due to international travel to and from New Zealand

    International Nuclear Information System (INIS)

    Smith, Inga J.; Rodger, Craig J.

    2009-01-01

    International air transport emissions are not subject to liability under the Kyoto Protocol. However, pressure is mounting globally for international aviation to be included in post-Kyoto arrangements. In the absence of international collective action, a number of so-called carbon offsetting schemes have emerged that allow individual travellers and companies to compensate for their international air travel emissions. These schemes offer technological solutions, such as planting sink forests to sequester emissions. To consider the implications of future collective action, this paper presents a case study assessment of the physical feasibility of five schemes for all short duration journeys to and from New Zealand. This is the first comprehensive national-level case study assessment of competing offsetting options for international aviation emissions in the peer-reviewed literature. The CO 2 -e emissions produced by the air travel of international visitors to New Zealand, and for New Zealand residents travelling overseas, is calculated in this paper to be 7893 and 3948 Gg, respectively, in 2005. It is then shown that no single offsetting scheme targeted inside the country appears physically and/or politically realistic. This indicates the sheer size of these emissions, and the challenge that the international community faces for collective action on this matter. (author)

  20. A simplified method to calculate the stresses in straight pipes due to laminar flow of a stratified medium with two different temperatures

    International Nuclear Information System (INIS)

    Cutrim, J.H.; Kizivat, V.

    1984-01-01

    A simplified method to calculate the stresses in straight pipes due to laminar flow of a stratified medium with two different temperatures is presented. It is based on the equilibrium equations and conservative assumptions as usual in practice. Numerical results are obtained for the 'banana' and 'pera' modes of deformation due to thermal stratification; the former case appears to be most important. In order to be able to perform such a fatigue damage analysis in practice under several complex load conditions, an existing program for fatigue damage analysis was provided with more substantial details. All the assumptions crucial for the use of ASME code were retained. The inclusion of stresses due to stratifications in the fatigue damage analysis is completed through extension of ASME NB 3650. (Author) [pt

  1. Status report: Intergranular stress corrosion cracking of BWR core shrouds and other internal components

    International Nuclear Information System (INIS)

    1996-03-01

    On July 25, 1994, the US Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 94-03 to obtain information needed to assess compliance with regulatory requirements regarding the structural integrity of core shrouds in domestic boiling water reactors (BWRs). This report begins with a brief description of the safety significance of intergranular stress corrosion cracking (IGSCC) as it relates to the design and function of BWR core shrouds and other internal components. It then presents a brief history of shroud cracking events both in the US and abroad, followed by an indepth summary of the industry actions to address the issue of IGSCC in BWR core shrouds and other internal components. This report summarizes the staff's basis for issuing GL 94-03, as well as the staff's assessment of plant-specific responses to GL 94-03. The staff is continually evaluating the licensee inspection programs and the results from examinations of BWR core shrouds and other internal components. This report is representative of submittals to and evaluations by the staff as of September 30, 1995. An update of this report will be issued at a later date

  2. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    International Nuclear Information System (INIS)

    Yoshida, Go J.; Saya, Hideyuki

    2014-01-01

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 high / Fbw7 high / c-Myc low and proliferative cancer stem-like cells with CD44v8-10 high / Fbw7 low / c-Myc high

  3. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Go J., E-mail: medical21go@yahoo.co.jp; Saya, Hideyuki

    2014-01-10

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup high}/ c-Myc {sup low} and proliferative cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup low}/ c-Myc {sup high}.

  4. Stress-induced grey matter loss determined by MRI is primarily due to loss of dendrites and their synapses.

    Science.gov (United States)

    Kassem, Mustafa S; Lagopoulos, Jim; Stait-Gardner, Tim; Price, William S; Chohan, Tariq W; Arnold, Jonathon C; Hatton, Sean N; Bennett, Maxwell R

    2013-04-01

    Stress, unaccompanied by signs of post-traumatic stress disorder, is known to decrease grey matter volume (GMV) in the anterior cingulate cortex (ACC) and hippocampus but not the amygdala in humans. We sought to determine if this was the case in stressed mice using high-resolution magnetic resonance imaging (MRI) and to identify the cellular constituents of the grey matter that quantitatively give rise to such changes. Stressed mice showed grey matter losses of 10 and 15 % in the ACC and hippocampus, respectively but not in the amygdala or the retrosplenial granular area (RSG). Concurrently, no changes in the number or volumes of the somas of neurons, astrocytes or oligodendrocytes were detected. A loss of synaptic spine density of up to 60 % occurred on different-order dendrites in the ACC and hippocampus (CA1) but not in the amygdala or RSG. The loss of spines was accompanied by decreases in cumulative dendritic length of neurons of over 40 % in the ACC and hippocampus (CA1) giving rise to decreases in volume of dendrites of 2.6 mm(3) for the former and 0.6 mm(3) for the latter, with no change in the amygdala or RSG. These values are similar to the MRI-determined loss of GMV following stress of 3.0 and 0.8 mm(3) in ACC and hippocampus, respectively, with no changes in the amygdala or RSG. This quantitative study is the first to relate GMV changes in the cortex measured with MRI to volume changes in cellular constituents of the grey matter.

  5. Early identification in primary health care of people at risk for sick leave due to work-related stress - study protocol of a randomized controlled trial (RCT).

    Science.gov (United States)

    Holmgren, Kristina; Sandheimer, Christine; Mårdby, Ann-Charlotte; Larsson, Maria E H; Bültmann, Ute; Hange, Dominique; Hensing, Gunnel

    2016-11-25

    Early identification of persons at risk of sickness absence due to work-related stress is a crucial problem for society in general, and primary health care in particular. Tho date, no established method to do this exists. This project's aim is to evaluate whether systematic early identification of work-related stress can prevent sickness absence. This paper presents the study design, procedure and outcome measurements, as well as allocation and baseline characteristics of the study population. The study is a two-armed randomized controlled trial with follow-up at 3, 6 and 12 months. Non-sick-listed employed women and men, aged 18 to 64 years, who had mental and physical health complaints and sought care at primary health care centers (PHCC) were eligible to participate. At baseline work-related stress was measured by the Work Stress Questionnaire (WSQ), combined with feedback at consultation, at PHCC. The preventive intervention included early identification of work-related stress by the WSQ, GP training in the use of WSQ, GP feedback at consultation and finding suitable preventive measures. A process evaluation was used to explore how to facilitate future implementation and structural use of the WSQ at the PHCC. The primary outcome to compare the preventive sick leave intervention by the general practitioner (GP) versus treatment as usual is sick leave data obtained from the Swedish Social Insurance Agency register. Early screening for sick leave due to work-related stress makes it possible not only to identify those at risk for sick leave, but also to put focus on the patient's specific work-related stress problems, which can be helpful in finding suitable preventive measures. This study investigates if use of the WSQ by GPs at PHCCs, combined with feedback at consultation, prevents future sickness absence. ClinicalTrials.gov. Identifier: NCT02480855 . Registered 20 May 2015.

  6. Chronic restraint stress promotes learning and memory impairment due to enhanced neuronal endoplasmic reticulum stress in the frontal cortex and hippocampus in male mice.

    Science.gov (United States)

    Huang, Rong-Rong; Hu, Wen; Yin, Yan-Yan; Wang, Yu-Chan; Li, Wei-Ping; Li, Wei-Zu

    2015-02-01

    Chronic stress has been implicated in many types of neurodegenerative diseases, such as Alzheimer's disease (AD). In our previous study, we demonstrated that chronic restraint stress (CRS) induced reactive oxygen species (ROS) overproduction and oxidative damage in the frontal cortex and hippocampus in mice. In the present study, we investigated the effects of CRS (over a period of 8 weeks) on learning and memory impairment and endoplasmic reticulum (ER) stress in the frontal cortex and hippocampus in male mice. The Morris water maze was used to investigate the effects of CRS on learning and memory impairment. Immunohistochemistry and immunoblot analysis were also used to determine the expression levels of protein kinase C α (PKCα), 78 kDa glucose-regulated protein (GRP78), C/EBP-homologous protein (CHOP) and mesencephalic astrocyte-derived neurotrophic factor (MANF). The results revealed that CRS significantly accelerated learning and memory impairment, and induced neuronal damage in the frontal cortex and hippocampus CA1 region. Moreover, CRS significantly increased the expression of PKCα, CHOP and MANF, and decreased that of GRP78 in the frontal cortex and hippocampus. Our data suggest that exposure to CRS (for 8 weeks) significantly accelerates learning and memory impairment, and the mechanisms involved may be related to ER stress in the frontal cortex and hippocampus.

  7. Guide for the putting int practice the control of internal contamination due to I-131 in hospitals

    International Nuclear Information System (INIS)

    1988-01-01

    The generalized use of radioactive installations in different branches of the Economy and Medicine makes essential the existence of a radiological surveillance systems that guarantees that exposure are kept within the limits established. Nuclear medicine workers in hospitals that handle I-131 constitutes a professional group that can be internally contaminated the aim of this guide is to give the entity the general instructions and the necessary methodology to fulfill the control of the internal contamination by this radionuclide

  8. Gentilly-2 NPP - Concrete aging effects on long term pre-stress losses and propagation of concrete cracking due to pressure testing

    International Nuclear Information System (INIS)

    Gocevski, V.

    2011-01-01

    This paper presents the results of the study intended to evaluate the post-tension long term losses and propagation of cracks in the envelope of Gentilly-2 Nuclear Power Plant reactor building. The numerical simulation of concrete, that takes into account elastic as well as inelastic strains due to loading, shrinkage strains due to drying or cooling and inelastic strains from alkali-aggregate reaction (AAR) related swelling, is explained. The simultaneous contribution of AAR, shrinkage and creep, are simulated using an enhanced elastic-plastic constitutive relation. The nonlinear relations are validated by comparing the numerically calculated strains with strain measurements from the extensometers placed in the concrete during the construction of the envelope. The post-tension losses/gains are evaluated for the vertical as well as horizontal cables. Also included is the result of pull-out test conducted on sample beam cast at the time of the reactor building construction with the same concrete mix, post-tension cable and force. Structural behaviour of the beam is simulated over the same period of time as the reactor building envelope. The test results are used also to calibrate the numerical model. The paper also includes discussion of the results obtained from the simulation of a standard internal high pressure test (145 kPa). The behavior of the reactor building envelope, prior to applied pressure, during the test and for the period of several months after the testing was simulated using an advanced numerical model and the results (strains) were compared with measured values. It was found that this method may be used as an approximate procedure for evaluation of post-tension losses/gains and assessment of propagation of cracking visible on the outside surfaces of the confinement building. In addition, a discussion of the negative effect of high post-tension on the air tightness of the confinement building of Gentilly-2. The comparison is made between the post

  9. Gentilly-2 NPP - Concrete aging effects on long term pre-stress losses and propagation of concrete cracking due to pressure testing

    Energy Technology Data Exchange (ETDEWEB)

    Gocevski, V. [Hydro-Quebe (Canada)

    2011-07-01

    This paper presents the results of the study intended to evaluate the post-tension long term losses and propagation of cracks in the envelope of Gentilly-2 Nuclear Power Plant reactor building. The numerical simulation of concrete, that takes into account elastic as well as inelastic strains due to loading, shrinkage strains due to drying or cooling and inelastic strains from alkali-aggregate reaction (AAR) related swelling, is explained. The simultaneous contribution of AAR, shrinkage and creep, are simulated using an enhanced elastic-plastic constitutive relation. The nonlinear relations are validated by comparing the numerically calculated strains with strain measurements from the extensometers placed in the concrete during the construction of the envelope. The post-tension losses/gains are evaluated for the vertical as well as horizontal cables. Also included is the result of pull-out test conducted on sample beam cast at the time of the reactor building construction with the same concrete mix, post-tension cable and force. Structural behaviour of the beam is simulated over the same period of time as the reactor building envelope. The test results are used also to calibrate the numerical model. The paper also includes discussion of the results obtained from the simulation of a standard internal high pressure test (145 kPa). The behavior of the reactor building envelope, prior to applied pressure, during the test and for the period of several months after the testing was simulated using an advanced numerical model and the results (strains) were compared with measured values. It was found that this method may be used as an approximate procedure for evaluation of post-tension losses/gains and assessment of propagation of cracking visible on the outside surfaces of the confinement building. In addition, a discussion of the negative effect of high post-tension on the air tightness of the confinement building of Gentilly-2. The comparison is made between the post

  10. Identification of potential internal control genes for real-time PCR analysis during stress response in Pyropia haitanensis

    Science.gov (United States)

    Wang, Xia; Feng, Jianhua; Huang, Aiyou; He, Linwen; Niu, Jianfeng; Wang, Guangce

    2017-11-01

    Pyropia haitanensis has prominent stress-resistance characteristics and is endemic to China. Studies into the stress responses in these algae could provide valuable information on the stress-response mechanisms in the intertidal Rhodophyta. Here, the effects of salinity and light intensity on the quantum yield of photosystem II in Py. haitanensis were investigated using pulse-amplitude-modulation fluorometry. Total RNA and genomic DNA of the samples under different stress conditions were isolated. By normalizing to the genomic DNA quantity, the RNA content in each sample was evaluated. The cDNA was synthesized and the expression levels of seven potential internal control genes were evaluated using qRT-PCR method. Then, we used geNorm, a common statistical algorithm, to analyze the qRT-PCR data of seven reference genes. Potential genes that may constantly be expressed under different conditions were selected, and these genes showed stable expression levels in samples under a salinity treatment, while tubulin, glyceraldehyde-3-phosphate dehydrogenase and actin showed stability in samples stressed by strong light. Based on the results of the pulse amplitude-modulation fluorometry, an absolute quantification was performed to obtain gene copy numbers in certain stress-treated samples. The stably expressed genes as determined by the absolute quantification in certain samples conformed to the results of the geNorm screening. Based on the results of the software analysis and absolute quantification, we proposed that elongation factor 3 and 18S ribosomal RNA could be used as internal control genes when the Py. haitanensis blades were subjected to salinity stress, and that α-tubulin and 18S ribosomal RNA could be used as the internal control genes when the stress was from strong light. In general, our findings provide a convenient reference for the selection of internal control genes when designing experiments related to stress responses in Py. haitanensis.

  11. Cross-shelf transport into nearshore waters due to shoaling internal tides in San Pedro Bay, CA

    Science.gov (United States)

    Noble, Marlene A.; Burt Jones,; Peter Hamilton,; Xu, Jingping; George Robertson,; Rosenfeld, Leslie; John Largier,

    2009-01-01

    In the summer of 2001, a coastal ocean measurement program in the southeastern portion of San Pedro Bay, CA, was designed and carried out. One aim of the program was to determine the strength and effectiveness of local cross-shelf transport processes. A particular objective was to assess the ability of semidiurnal internal tidal currents to move suspended material a net distance across the shelf. Hence, a dense array of moorings was deployed across the shelf to monitor the transport patterns associated with fluctuations in currents, temperature and salinity. An associated hydrographic program periodically monitored synoptic changes in the spatial patterns of temperature, salinity, nutrients and bacteria. This set of measurements show that a series of energetic internal tides can, but do not always, transport subthermocline water, dissolved and suspended material from the middle of the shelf into the surfzone. Effective cross-shelf transport occurs only when (1) internal tides at the shelf break are strong and (2) subtidal currents flow strongly downcoast. The subtidal downcoast flow causes isotherms to tilt upward toward the coast, which allows energetic, nonlinear internal tidal currents to carry subthermocline waters into the surfzone. During these events, which may last for several days, the transported water remains in the surfzone until the internal tidal current pulses and/or the downcoast subtidal currents disappear. This nonlinear internal tide cross-shelf transport process was capable of carrying water and the associated suspended or dissolved material from the mid-shelf into the surfzone, but there were no observation of transport from the shelf break into the surfzone. Dissolved nutrients and suspended particulates (such as phytoplankton) transported from the mid-shelf into the nearshore region by nonlinear internal tides may contribute to nearshore algal blooms, including harmful algal blooms that occur off local beaches.

  12. Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Samira Abdulai-Saiku

    2018-01-01

    Full Text Available Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change.  Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasma gondii -induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma gondii infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma gondii are dependent on variables in the environment that often go unreported in the published literature.

  13. Control superstructure of rigid polyelectrolytes in oppositely charged hydrogels via programmed internal stress

    Science.gov (United States)

    Takahashi, Riku; Wu, Zi Liang; Arifuzzaman, Md; Nonoyama, Takayuki; Nakajima, Tasuku; Kurokawa, Takayuki; Gong, Jian Ping

    2014-08-01

    Biomacromolecules usually form complex superstructures in natural biotissues, such as different alignments of collagen fibres in articular cartilages, for multifunctionalities. Inspired by nature, there are efforts towards developing multiscale ordered structures in hydrogels (recognized as one of the best candidates of soft biotissues). However, creating complex superstructures in gels are hardly realized because of the absence of effective approaches to control the localized molecular orientation. Here we introduce a method to create various superstructures of rigid polyanions in polycationic hydrogels. The control of localized orientation of rigid molecules, which are sensitive to the internal stress field of the gel, is achieved by tuning the swelling mismatch between masked and unmasked regions of the photolithographic patterned gel. Furthermore, we develop a double network structure to toughen the hydrogels with programmed superstructures, which deform reversibly under large strain. This work presents a promising pathway to develop superstructures in hydrogels and should shed light on designing biomimetic materials with intricate molecular alignments.

  14. Results of the Argentinian intercomparison on internal dosimetry – 2014. Interpretation of monitoring data for effective dose assessment due to internal exposure

    International Nuclear Information System (INIS)

    Rojo, A.M.; Puerta, N.; Gossio, S.; Gómez Parada, I.

    2015-01-01

    Internal dosimetry intercomparisons are essential for the verification of the models applied and the results consistency. To that aim, in 2014 the National Intercomparison Exercise was organized and coordinated by the Internal Dosimetry Laboratory of the Nuclear Regulatory Authority (ARN) of Argentina. Four simulated cases covering intakes of “1”3”1I, “1”3”7Cs and tritium were proposed. The exercise counted with the participation of four internal dosimetry services from the nuclear power plants (NA-SA CNA and NA-SA CNE) and the CNEA Atomic Centres: Bariloche (CAB) and Ezeiza (CAE). This report shows a complete analysis of the participant’s results in this exercise. (authors) [es

  15. Flow through internal elastic lamina affects shear stress on smooth muscle cells (3D simulations).

    Science.gov (United States)

    Tada, Shigeru; Tarbell, John M

    2002-02-01

    We describe a three-dimensional numerical simulation of interstitial flow through the medial layer of an artery accounting for the complex entrance condition associated with fenestral pores in the internal elastic lamina (IEL) to investigate the fluid mechanical environment around the smooth muscle cells (SMCs) right beneath the IEL. The IEL was modeled as an impermeable barrier to water flow except for the fenestral pores, which were assumed to be uniformly distributed over the IEL. The medial layer was modeled as a heterogeneous medium composed of a periodic array of cylindrical SMCs embedded in a continuous porous medium representing the interstitial proteoglycan and collagen matrix. Depending on the distance between the IEL bottom surface and the upstream end of the proximal layer of SMCs, the local shear stress on SMCs right beneath the fenestral pore could be more than 10 times higher than that on the cells far removed from the IEL under the conditions that the fenestral pore diameter and area fraction of pores were kept constant at 1.4 microm and 0.05, respectively. Thus these proximal SMCs may experience shear stress levels that are even higher than endothelial cells exposed to normal blood flow (order of 10 dyn/cm(2)). Furthermore, entrance flow through fenestral pores alters considerably the interstitial flow field in the medial layer over a spatial length scale of the order of the fenestral pore diameter. Thus the spatial gradient of shear stress on the most superficial SMC is noticeably higher than computed for endothelial cell surfaces.

  16. Determination of internal controls for quantitative gene expression of Isochrysis zhangjiangensis at nitrogen stress condition

    Science.gov (United States)

    Wu, Shuang; Zhou, Jiannan; Cao, Xupeng; Xue, Song

    2016-02-01

    Isochrysis zhangjiangensis is a potential marine microalga for biodiesel production, which accumulates lipid under nitrogen limitation conditions, but the mechanism on molecular level is veiled. Quantitative real-time polymerase chain reaction (qPCR) provides the possibility to investigate the gene expression levels, and a valid reference for data normalization is an essential prerequisite for firing up the analysis. In this study, five housekeeping genes, actin (ACT), α-tubulin (TUA), ß-tubulin (TUB), ubiquitin (UBI), 18S rRNA (18S) and one target gene, diacylglycerol acyltransferase (DGAT), were used for determining the reference. By analyzing the stabilities based on calculation of the stability index and on operating the two types of software, geNorm and bestkeeper, it showed that the reference genes widely used in higher plant and microalgae, such as UBI, TUA and 18S, were not the most stable ones in nitrogen-stressed I. zhangjiangensis, and thus are not suitable for exploring the mRNA expression levels under these experimental conditions. Our results show that ACT together with TUB is the most feasible internal control for investigating gene expression under nitrogen-stressed conditions. Our findings will contribute not only to future qPCR studies of I. zhangjiangensis, but also to verification of comparative transcriptomics studies of the microalgae under similar conditions.

  17. Study on the stress changes due to the regional groundwater exploitation based on a 3-D fully coupled poroelastic model: An example of the North China Plain

    Science.gov (United States)

    Cheng, H.; Zhang, H.; Pang, Y. J.; Shi, Y.

    2017-12-01

    With the quick urban development, over-exploitation of groundwater resources becomes more and more intense, which leads to not only widespread groundwater depression cones but also a series of harsh environmental and geological hazards. Among which, the most intuitive phenomenon is the ground subsidence in loose sediments. However, another direct consequence triggered by the groundwater depletion is the substantial crustal deformation and potential modulation of crustal stress underneath the groundwater over-pumping zones. In our previous 3-D viscoelastic finite element model, we found that continuous over-exploitation of groundwater resources in North China Plain during the past 60 years give rise to crustal-scale uplift reaching 4.9cm, with the Coulomb failure stress decreasing by up to 12 kPa, which may inhibit the nucleation of possible big earthquake events. Furthermore, according to the effective pressure principle and lab experiments, the pore pressure may also have changed due to the reduced water level. In order to quantitatively analyze the stress changes due to the regional groundwater exploitation in North China Plain, a three-dimensional fully coupled poroelastic finite element model is developed in this study. The high resolution topography, grounwater level fluctuation, fault parameters and etc, are taken into consideration. Further, the changes of Coulomb Failure Stress, in correspondence to elastic stress and pore pressure changes induced by fluid diffusion are calculated. Meanwhile, the elastic strain energy accumulation in region due to the regional groundwater exploitation is obtained. Finally, we try to analyze the seismic risk of major faults within North China Plain to further discuss the regional seismic activities.

  18. Factorial Validity and Internal Consistency of Malaysian Adapted Depression Anxiety Stress Scale - 21 in an Adolescent Sample

    OpenAIRE

    Hairul Anuar Hashim; Freddy Golok; Rosmatunisah Ali

    2011-01-01

    Background: Psychometrically sound measurement instrument is a fundamental requirement across broad range of research areas. In negative affect research, Depression Anxiety Stress Scale (DASS) has been identified as a psychometrically sound instrument to measure depression, anxiety and stress, especially the 21-item version. However, its psychometric properties in adolescents have been less consistent. Objectives: Thus, the present study sought to examine the factorial validity and internal c...

  19. Maxwell-Cattaneo Heat Convection and Thermal Stresses Responses of a Semi-Infinite Medium to High-Speed Laser Heating due to High Speed Laser Heating

    Directory of Open Access Journals (Sweden)

    Abdallah I. A.

    2009-07-01

    Full Text Available Based on Maxwell-Cattaneo convection equation, the thermoelasticity problem is in- vestigated in this paper. The analytic solution of a boundary value problem for a semi- infinite medium with traction free surface heated by a high-speed laser-pulses have Dirac temporal profile is solved. The temperature, the displacement and the stresses distributions are obtained analytically using the Laplace transformation, and discussed at small time duration of the laser pulses. A numerical study for Cu as a target is performed. The results are presented graphically. The obtained results indicate that the small time duration of the laser pulses has no e ect on the finite velocity of the heat con- ductivity, but the behavior of the stress and the displacement distribution are affected due to the pulsed heating process and due to the structure of the governing equations.

  20. Age and educational inequalities in smoking cessation due to three population-level tobacco control interventions: findings from the International Tobacco Control (ITC) Netherlands Survey

    NARCIS (Netherlands)

    Nagelhout, G.E.; Crone, M.R.; van den Putte, B.; Willemsen, M.C.; Fong, G.T.; de Vries, H.

    2013-01-01

    This study aimed to examine age and educational inequalities in smoking cessation due to the implementation of a tobacco tax increase, smoke-free legislation and a cessation campaign. Longitudinal data from 962 smokers aged 15 years and older were used from three survey waves of the International

  1. Age and Educational Inequalities in Smoking Cessation Due to Three Population-Level Tobacco Control Interventions: Findings from the International Tobacco Control (ITC) Netherlands Survey

    Science.gov (United States)

    Nagelhout, Gera E.; Crone, Matty R.; van den Putte, Bas; Willemsen, Marc C.; Fong, Geoffrey T.; de Vries, Hein

    2013-01-01

    This study aimed to examine age and educational inequalities in smoking cessation due to the implementation of a tobacco tax increase, smoke-free legislation and a cessation campaign. Longitudinal data from 962 smokers aged 15 years and older were used from three survey waves of the International Tobacco Control (ITC) Netherlands Survey. The 2008…

  2. Measurements of internal stresses in bond coating using high energy x-rays from synchrotron radiation source

    CERN Document Server

    Suzuki, K; Akiniwa, Y; Nishio, K; Kawamura, M; Okado, H

    2002-01-01

    Thermal barrier coating (TBC) techniques enable high temperature combustion of turbines made of Ni-base alloy. TBC is made of zirconia top coating on NiCoCrAlY bond coating. The internal stresses in the bond coating play essential role in the delamination or fracture of TBC in service. With the X-rays from laboratory equipments, it is impossible to measure nondestructively the internal stress in the bond coating under the top coating. synchrotron radiations with a high energy and high brightness have a large penetration depth as compared with laboratory X-rays. Using the high energy X-rays from the synchrotron radiation, it is possible to measure the internal stress in the bond coating through the top coating. In this study, the furnace, which can heat a specimen to 1473 K, was developed for the stress measurement of the thermal barrier coatings. The internal stresses in the bond coating were measured at the room temperature, 773 K, 1073 K and 1373 K by using the 311 diffraction from Ni sub 3 Al with about 73...

  3. Psychological well-being of interns in Hong Kong: what causes them stress and what helps them.

    Science.gov (United States)

    Lam, T P; Wong, J G W S; Ip, Mary S M; Lam, K F; Pang, S L

    2010-01-01

    Many doctors experience psychological ill health. Interns are known to be particularly vulnerable. To examine the level of depression, anxiety and stress in interns in Hong Kong, as well as the causes and how they cope. A questionnaire was designed based on the themes identified in three focus groups of medical graduates of Year 2004 of the University of Hong Kong. The 21-item Depression, Anxiety and Stress Scale (DASS 21) was also administered. All 155 graduates of the same year were invited to participate with a response rate of 63%. Percentages of respondents with abnormal levels of depression, anxiety and stress were 35.8%, 35.4% and 29.2%, respectively. Frequent calls during night shift, long working hours and heavy workload constituted the most significant stressors. Factor analysis of the stressors showed that seven factors could explain 68% of the total variance: multidisciplinary team working issues, clinical difficulties, job seeking and employment, workload issues, ethical and interpersonal issues, adjustment to job rotation and performance appraisal. Holidays, peers and sleep offered the most significant relief. Interns experience considerable depression, anxiety and stress. The source of stress is multi-faceted, but workload is the most significant stressor. Peer support groups may relief stress.

  4. Stress-intensity factors for a thick-walled cylinder containing an annular imbedded or external or internal surface crack

    Science.gov (United States)

    Erdol, R.; Erdogan, F.

    1976-01-01

    The elastostatic axisymmetric problem for a long thick-walled cylinder containing a ring-shaped internal or edge crack is considered. Using the standard transform technique the problem is formulated in terms of an integral equation which has a simple Cauchy kernel for the internal crack and a generalized Cauchy kernel for the edge crack as the dominant part. As examples the uniform axial load and the steady-state thermal stress problems have been solved and the related stress intensity factors have been calculated. Among other findings the results show that in the cylinder under uniform axial stress containing an internal crack the stress intensity factor at the inner tip is always greater than that at the outer tip for equal net ligament thicknesses and in the cylinder with an edge crack which is under a state of thermal stress the stress intensity factor is a decreasing function of the crack depth, tending to zero as the crack depth approaches the wall thickness.

  5. Validation of post-traumatic stress disorder (PTSD) and complex PTSD using the International Trauma Questionnaire.

    Science.gov (United States)

    Hyland, P; Shevlin, M; Brewin, C R; Cloitre, M; Downes, A J; Jumbe, S; Karatzias, T; Bisson, J I; Roberts, N P

    2017-09-01

    The 11th version of the International Classification of Diseases (ICD-11) has proposed two related trauma diagnoses: Post-traumatic stress disorder (PTSD) and Complex PTSD (CPTSD). Using a newly developed, disorder-specific measure of PTSD and CPTSD called the International Trauma Questionnaire (ITQ) the current study will (i) assess the factorial validity of ICD-11 PTSD and CPTSD; (ii) provide the first test of the discriminant validity of these constructs; and (iii) provide the first comparison of ICD-11, and Diagnostic and Statistical Manual, Fifth Edition (DSM-5), PTSD diagnostic rates using disorder-specific measures. ICD-11 and DSM-5 PTSD-specific measures were completed by a British clinical sample of trauma-exposed patients (N = 171). The structure and validity of ICD-11 PTSD and CPTSD were assessed by means of factor analysis and assessing relationships with criterion variables. Diagnostic rates under ICD-11 were significantly lower than those under DSM-5. A two-factor second-order model reflecting the distinction between PTSD and CPTSD best represented the data from the ITQ; and the PTSD and CPTSD factors differentially predicted multiple psychological variables. The factorial and discriminant validity of ICD-11 PTSD and CPTSD was supported, and ICD-11 produces fewer diagnostic cases than DSM-5. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. A thin rivulet or ridge subject to a uniform transverse shear stress at its free surface due to an external airflow

    KAUST Repository

    Sullivan, J. M.

    2012-01-01

    We use the lubrication approximation to analyze three closely related problems involving a thin rivulet or ridge (i.e., a two-dimensional droplet) of fluid subject to a prescribed uniform transverse shear stress at its free surface due to an external airflow, namely a rivulet draining under gravity down a vertical substrate, a rivulet driven by a longitudinal shear stress at its free surface, and a ridge on a horizontal substrate, and find qualitatively similar behaviour for all three problems. We show that, in agreement with previous numerical studies, the free surface profile of an equilibrium rivulet/ridge with pinned contact lines is skewed as the shear stress is increased from zero, and that there is a maximum value of the shear stress beyond which no solution with prescribed semi-width is possible. In practice, one or both of the contact lines will de-pin before this maximum value of the shear stress is reached, and so we consider situations in which the rivulet/ridge de-pins at one or both contact lines. In the case of de-pinning only at the advancing contact line, the rivulet/ridge is flattened and widened as the shear stress is increased from its critical value, and there is a second maximum value of the shear stress beyond which no solution with a prescribed advancing contact angle is possible. In contrast, in the case of de-pinning only at the receding contact line, the rivulet/ridge is thickened and narrowed as the shear stress is increased from its critical value, and there is a solution with a prescribed receding contact angle for all values of the shear stress. In general, in the case of de-pinning at both contact lines there is a critical "yield" value of the shear stress beyond which no equilibrium solution is possible and the rivulet/ridge will evolve unsteadily. In the Appendix, we show that an equilibrium rivulet/ridge with prescribed flux/area is quasi-statically stable to two-dimensional perturbations. © 2012 American Institute of Physics.

  7. Does increased Nitric Oxide production and oxidative stress due to high fat diet affect cardiac function after myocardial infarction?

    Directory of Open Access Journals (Sweden)

    Marjan Aghajani

    2017-01-01

    Full Text Available Background &Objectives: High fat (HF diet by affecting the oxidative stress and nitric oxide (NO production may lead to different effects on function of the heart after myocardial infarction (MI. In the present study we aimed to address the hypothesis that high release of NO by activated macrophages affects LV function after MI.Methods: The animals were randomly divided into four groups comprising each of 10 rats: 1 Sham; 2 MI; 3 Sham+ HF diet; 4 MI+ HF diet. Animals fed with HF diet 30 days before sham and MI surgery. MI was induced by permanent ligation of left anterior descending coronary artery (LAD. Nitric oxide (NO production of peritoneal macrophages, the concentrations of MDA in the heart and the infarct size were measured.Results: Our study indicated that HF has adverse effects on myocardium and it may increase NO production as well as oxidative stress, resulting in augmentation of infarct size.Conclusion: Our results add to our knowledge that HF diet was associated with overproduction of NO by peritoneal macrophages and ROS that lead to development of infarct size and adverse remodeling.

  8. Tolerance of spermatogonia to oxidative stress is due to high levels of Zn and Cu/Zn superoxide dismutase.

    Directory of Open Access Journals (Sweden)

    Fritzie T Celino

    Full Text Available BACKGROUND: Spermatogonia are highly tolerant to reactive oxygen species (ROS attack while advanced-stage germ cells such as spermatozoa are much more susceptible, but the precise reason for this variation in ROS tolerance remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using the Japanese eel testicular culture system that enables a complete spermatogenesis in vitro, we report that advanced-stage germ cells undergo intense apoptosis and exhibit strong signal for 8-hydroxy-2'-deoxyguanosine, an oxidative DNA damage marker, upon exposure to hypoxanthine-generated ROS while spermatogonia remain unaltered. Activity assay of antioxidant enzyme, superoxide dismutase (SOD and Western blot analysis using an anti-Copper/Zinc (Cu/Zn SOD antibody showed a high SOD activity and Cu/Zn SOD protein concentration during early spermatogenesis. Immunohistochemistry showed a strong expression for Cu/Zn SOD in spermatogonia but weak expression in advanced-stage germ cells. Zn deficiency reduced activity of the recombinant eel Cu/Zn SOD protein. Cu/Zn SOD siRNA decreased Cu/Zn SOD expression in spermatogonia and led to increased oxidative damage. CONCLUSIONS/SIGNIFICANCE: These data indicate that the presence of high levels of Cu/Zn SOD and Zn render spermatogonia resistant to ROS, and consequently protected from oxidative stress. These findings provide the biochemical basis for the high tolerance of spermatogonia to oxidative stress.

  9. Attenuation of Microbial Stress Due to Nano-Ag and Nano-TiO2 Interactions under Dark Conditions.

    Science.gov (United States)

    Wilke, Carolyn M; Tong, Tiezheng; Gaillard, Jean-François; Gray, Kimberly A

    2016-10-04

    Engineered nanomaterials (ENMs) are incorporated into thousands of commercial products, and their release into environmental systems creates complex mixtures with unknown toxicological outcomes. To explore this scenario, we probe the chemical and toxicological interactions of nanosilver (n-Ag) and nanotitania (n-TiO 2 ) in Lake Michigan water, a natural aqueous medium, under dark conditions. We find that the presence of n-Ag induces a stress response in Escherichia coli, as indicated by a decrease in ATP production observed at low concentrations (in the μg L -1 range), with levels that are environmentally relevant. However, when n-Ag and n-TiO 2 are present together in a mixture, n-TiO 2 attenuates the toxicity of n-Ag at and below 20 μg L -1 by adsorbing Ag + (aq) . We observe, however, that toxic stress cannot be explained by dissolved silver concentrations alone and, therefore, must also depend on silver associated with the nanoscale fraction. Although the attenuating effect of n-TiO 2 on n-Ag's toxicity is limited, this study emphasizes the importance of probing the toxicity of ENM mixtures under environmental conditions to assess how chemical interactions between nanoparticles change the toxicological effects of single ENMs in unexpected ways.

  10. Photoelastic investigation of the stresses in a stepped cylinder under internal pressure

    International Nuclear Information System (INIS)

    Sawa, Yoshiaki; Nishida, Masataka

    1985-01-01

    The states of stress distribution of the stepped cylinder under inner-pressure are studied by means of stress freezing photoelastic method. The experimental results reveal that fiber stress concentration occurs on the circular arc and hoop stress concentration occurs at the jointing point of the straight line and the arc and that each maximum value of fiver stress and hoop stress depends very greatly on the diameter of a small cylinder and the radius of curvature. And the relationship between the stress concentration factors and these shape factors are given. Effects of wall thickness on the stress concentration factors are also determined. (author)

  11. Personality assessment inventory internalizing and externalizing structure in veterans with posttraumatic stress disorder: associations with aggression.

    Science.gov (United States)

    Van Voorhees, Elizabeth E; Dennis, Paul A; Elbogen, Eric B; Clancy, Carolina P; Hertzberg, Michael A; Beckham, Jean C; Calhoun, Patrick S

    2014-01-01

    Posttraumatic stress disorder (PTSD) is associated with aggressive behavior in veterans, and difficulty controlling aggressive urges has been identified as a primary postdeployment readjustment concern. Yet only a fraction of veterans with PTSD commit violent acts. The goals of this study were to (1) examine the higher-order factor structure of Personality Assessment Inventory (PAI) scales in a sample of U.S. military veterans seeking treatment for PTSD; and (2) to evaluate the incremental validity of higher-order latent factors of the PAI over PTSD symptom severity in modeling aggression. The study sample included male U.S. Vietnam (n = 433) and Iraq/Afghanistan (n = 165) veterans who were seeking treatment for PTSD at an outpatient Veterans Affairs (VA) clinic. Measures included the Clinician Administered PTSD Scale, the PAI, and the Conflict Tactics Scale. The sample was randomly split into two equal subsamples (n's = 299) to allow for cross-validation of statistically derived factors. Parallel analysis, variable clustering analysis, and confirmatory factor analyses were used to evaluate the factor structure, and regression was used to examine the association of factor scores with self-reports of aggression over the past year. Three factors were identified: internalizing, externalizing, and substance abuse. Externalizing explained unique variance in aggression beyond PTSD symptom severity and demographic factors, while internalizing and substance abuse did not. Service era was unrelated to reports of aggression. The constructs of internalizing versus externalizing dimensions of PTSD may have utility in identifying characteristics of combat veterans in the greatest need of treatment to help manage aggressive urges. Published 2014 Wiley Periodicals, Inc.

  12. Late-Onset Massive Epistaxis due to a Ruptured Traumatic Internal Carotid Artery Aneurysm: A Case Report

    OpenAIRE

    Arai, Nobuhiko; Nakamura, Akiyoshi; Tabuse, Masanao; Miyazaki, Hiromichi

    2016-01-01

    A traumatic internal carotid artery (ICA) aneurysm is rare and difficult to treat. Trapping of ICA is commonly performed owing to the difficulty of directly approaching ICA aneurysms. Recently, coiling the aneurysm itself was recommended if possible. However, it is controversial which of methods are best to completely treat aneurysm. We present the case of a 74-year-old man, who had experienced a head injury 8 years previously, with recurrent severe epistaxis. An ICA aneurysm was detected on ...

  13. Small-bowel volvulus in late pregnancy due to internal hernia after laparoscopic Roux-en-Y gastric bypass.

    Science.gov (United States)

    Naef, Markus; Mouton, Wolfgang G; Wagner, Hans E

    2010-12-01

    Internal hernias are a specific cause of acute abdominal pain and are a well-known complication after laparoscopic Roux-en-Y gastric bypass for morbid obesity. Although internal hernias are a rare cause of intestinal obstruction, they may evolve towards serious complications, such as extensive bowel ischemia and gangrene, with the need for bowel resection and sometimes for a challenging reconstruction of intestinal continuity. The antecolic position of the Roux limb is associated with a decrease in the incidence of small-bowel obstruction and internal hernias. The best prevention of the formation of these hernias is probably by closure of potential mesenteric defects at the initial operation with a non-absorbable running suture. We present a patient in late pregnancy with a small-bowel volvulus following laparoscopic Roux-en-Y gastric bypass for morbid obesity and discuss the available literature. For a favorable obstetric and neonatal outcome, it is crucial not to delay surgical exploration and an emergency operation usually is mandatory.

  14. Analysis of residual stresses due to roll-expansion process: Finite element computation and validation by experimental tests

    International Nuclear Information System (INIS)

    Aufaure, M.; Boudot, R.; Zacharie, G.; Proix, J.M.

    1987-01-01

    The steam generator heat exchangers of pressurized water reactors are made of U-shaped tubes, both ends of them being fixed to a plate by roll-expansion. This process consists in increasing the tube section by means of a rotating tool in order to apply its outer side to the surface of the hole through the plate. As reported by de Keroulas (1986), in service cracks appeared on these tubes in the transition from expanded to nonexpanded portions. So we developed a program to compute residual stresses at the surface of the tubes, which caused their cracking, and to endeavour to lower their level by acting on some parameters. This program was validated by experimental tests. (orig.)

  15. OCO-2 chlorophyll fluorescence tracks late-summer photosynthesis decrease due to water stress at Missouri Ozark site

    Science.gov (United States)

    He, L.; Frankenberg, C.; Wood, J. D.; Sun, Y.

    2017-12-01

    Accurate estimate of the photosynthetic uptake of CO2, denoted gross primary productivity (GPP), is important to understand and quantify the carbon cycles at regional to global scales, and has implications in crop and forest management. Solar-induced chlorophyll fluorescence (SIF) retrieved from space was found to be strongly correlated with GPP and is now being used as a potential new technique to estimate photosynthetic rates at large scale. We selected the Missouri Ozark Site as a test bed, a well-characterized Eddy Covariance site in deciduous broadleaf forests, to explore the relationships of vegetation indices (VIs) and SIF with GPP and their response to environmental conditions. We find that both GPP fluxes and OCO-2 SIF decreased in late summer at the Ozark Site, directly related to water stress, evidenced by a progressive decrease in soil moisture and concomitant changer in leaf water potential. However, VIs (both NDVI and EVI) stayed stable during the same period. With a focus on this wet-dry transition period, we analyze driving factors of changes in GPP and SIF, which appear to be linearly related even in this period with little reflectance changes. We also used the Soil Canopy Observation, Photochemistry and Energy fluxes (SCOPE) model to compare observations of SIF and GPP against measurement. The primary motivation is not only to quantify the expected correlations between the GPP and SIF but also to validate performance of SCOPE in reproducing such correlations, which have not been tested against independent observations. This study clearly underlines the potential of SIF measurements to study moderate water stress and its impact on photosynthesis.

  16. Blubber cortisol: a potential tool for assessing stress response in free-ranging dolphins without effects due to sampling.

    Directory of Open Access Journals (Sweden)

    Nicholas M Kellar

    Full Text Available When paired with dart biopsying, quantifying cortisol in blubber tissue may provide an index of relative stress levels (i.e., activation of the hypothalamus-pituitary-adrenal axis in free-ranging cetacean populations while minimizing the effects of the act of sampling. To validate this approach, cortisol was extracted from blubber samples collected from beach-stranded and bycaught short-beaked common dolphins using a modified blubber steroid isolation technique and measured via commercially available enzyme immunoassays. The measurements exhibited appropriate quality characteristics when analyzed via a bootstraped stepwise parallelism analysis (observed/expected = 1.03, 95%CI: 99.6 - 1.08 and showed no evidence of matrix interference with increasing sample size across typical biopsy tissue masses (75-150 mg; r(2 = 0.012, p = 0.78, slope = 0.022 ng(cortisol deviation/ul(tissue extract added. The relationships between blubber cortisol and eight potential cofactors namely, 1 fatality type (e.g., stranded or bycaught, 2 specimen condition (state of decomposition, 3 total body length, 4 sex, 5 sexual maturity state, 6 pregnancy status, 7 lactation state, and 8 adrenal mass, were assessed using a Bayesian generalized linear model averaging technique. Fatality type was the only factor correlated with blubber cortisol, and the magnitude of the effect size was substantial: beach-stranded individuals had on average 6.1-fold higher cortisol levels than those of bycaught individuals. Because of the difference in conditions surrounding these two fatality types, we interpret this relationship as evidence that blubber cortisol is indicative of stress response. We found no evidence of seasonal variation or a relationship between cortisol and the remaining cofactors.

  17. Induction of apoptosis by zerumbone isolated from Zingiber zerumbet (L.) Smith in protozoan parasite Leishmania donovani due to oxidative stress

    OpenAIRE

    Mukherjee, Debarati; Singh, Chingakham Brajakishor; Dey, Somaditya; Mandal, Supratim; Ghosh, Joydip; Mallick, Suvadip; Hussain, Aabid; Swapana, Ningombam; Ross, Samir Anis; Pal, Chiranjib

    2016-01-01

    Abstract In the present context of emergence of resistance aligned with the conventional anti-leishmanial drugs and occasional treatment failure compelled us to continue the search for replaceable therapeutic leads against Leishmaniainfection. Various ginger spices of the Zingiberaceae family are widely used as spices, flavouring agents, and medicines in Southeast Asia because of their unique flavour as well as due to their medicinal properties. Zerumbone, a natural component of Zingiber zeru...

  18. Health problems associated with international travel: a case of cutaneous myiasis in China due to Cordylobia anthropophaga imported from Uganda.

    Science.gov (United States)

    Ruan, Wei; Feng, Yan; Zhang, Lingling; Sun, Jimin; Yao, Linong

    2014-12-01

    More affordable international travel, global trade and commerce, and the exporting of labor have all contributed to international population mobility. Furthermore, population migration leads to the incidence or recurrence of once-controlled diseases. Evidence shows that the popularity of travel can impact health through imported infections and illness. Imported cutaneous myiasis, a type of skin lesion, has attracted the attention of the current authors. This condition often occurs among travelers and it has been reported in several non-endemic countries. However, diagnosis of myiasis and identification of the larvae are difficult. Advances in molecular detection techniques could provide a new way to identify larvae. This study used sequencing of the 28S rRNA gene and morphology to identify the larva infesting the upper arm of a Chinese woman returning from Uganda. The larva was identified as Cordylobia anthropophaga (C. anthropophaga) and the sequences were submitted to GenBank (accession number: KM506761). As foreign interaction increases, imported health problems may become more common in China. Knowledge about various pathogens needs to be increased and molecular methods need to be used to accurately identify those pathogens.

  19. Adiabatic decay of internal solitons due to Earth's rotation within the framework of the Gardner-Ostrovsky equation

    Science.gov (United States)

    Obregon, Maria; Raj, Nawin; Stepanyants, Yury

    2018-03-01

    The adiabatic decay of different types of internal wave solitons caused by the Earth's rotation is studied within the framework of the Gardner-Ostrovsky equation. The governing equation describing such processes includes quadratic and cubic nonlinear terms, as well as the Boussinesq and Coriolis dispersions: (ut + c ux + α u ux + α1 u2 ux + β uxxx)x = γ u. It is shown that at the early stage of evolution solitons gradually decay under the influence of weak Earth's rotation described by the parameter γ. The characteristic decay time is derived for different types of solitons for positive and negative coefficients of cubic nonlinearity α1 (both signs of that parameter may occur in the oceans). The coefficient of quadratic nonlinearity α determines only a polarity of solitary wave when α1 0. It is found that the adiabatic theory describes well the decay of solitons having bell-shaped profiles. In contrast to that, large amplitude table-top solitons, which can exist when α1 is negative, are structurally unstable. Under the influence of Earth's rotation, they transfer first to the bell-shaped solitons, which decay then adiabatically. Estimates of the characteristic decay time of internal solitons are presented for the real oceanographic conditions.

  20. Bimodal effect of oxidative stress in internal anal sphincter smooth muscle

    Science.gov (United States)

    Singh, Jagmohan; Kumar, Sumit

    2015-01-01

    Changes in oxidative stress may affect basal tone and relaxation of the internal anal sphincter (IAS) smooth muscle in aging. We examined this issue by investigating the effects of the oxidative stress inducer 6-anilino-5,8-quinolinedione (LY-83583) in basal as well as U-46619-stimulated tone, and nonadrenergic, noncholinergic (NANC) relaxation in rat IAS. LY-83583, which works via generation of reactive oxygen species in living cells, produced a bimodal effect in IAS tone: lower concentrations (0.1 nM to 10 μM) produced a concentration-dependent increase, while higher concentrations (50–100 μM) produced a decrease in IAS tone. An increase in IAS tone by lower concentrations was associated with an increase in RhoA/Rho kinase (ROCK) activity. This was evident by the increase in RhoA/ROCK in the particulate fractions, in ROCK activity, and in the levels of phosphorylated (p) Thr696-myosin phosphatase target subunit 1 and pThr18/Ser19-20-kDa myosin light chain. Conversely, higher concentrations of LY-83583 produced inhibitory effects on RhoA/ROCK. Interestingly, both the excitatory and inhibitory effects of LY-83583 in the IAS were reversed by superoxide dismutase. The excitatory effects of LY-83583 were found to resemble those with neuronal nitric oxide synthase (nNOS) inhibition by l-NNA, since it produced a significant increase in the IAS tone and attenuated NANC relaxation. These effects of LY-83583 and l-NNA were reversible by l-arginine. This suggests the role of nNOS inhibition and RhoA/ROCK activation in the increase in IAS tone by LY-83583. These data have important implications in the pathophysiology and therapeutic targeting of rectoanal disorders, especially associated with IAS dysfunction. PMID:26138467

  1. Using X-ray microbeam diffraction to study the long-range internal stresses in aluminum processed by ECAP

    International Nuclear Information System (INIS)

    Lee, I-Fang; Phan, Thien Q.; Levine, Lyle E.; Tischler, Jonathan Z.; Geantil, Peter T.; Huang, Yi; Langdon, Terence G.; Kassner, Michael E.

    2013-01-01

    Aluminum alloy 1050 was processed by equal-channel angular pressing (ECAP) using a single pass (equivalent uniaxial strain of about 0.88). Long-range internal stresses (LRISs) were assessed in the grain/subgrain interiors using X-ray microbeam diffraction to measure the spacing of {5 3 1} planes, with normals oriented approximately +27.3°, +4.9° and −17.5° off the pressing (axial) direction. The results are consistent with mechanical analysis that suggests the maximum tensile plastic-strain after one pass is expected for +22.5°, roughly zero along the pressing axis, and maximum compressive strain for the −67.5° direction. The magnitude of the measured maximum compressive long-range internal stress is about 0.13σ a (applied stress) in low-dislocation regions within the grain/subgrain interiors. This work is placed in the context of earlier work where convergent beam electron diffraction was used to analyze LRISs in close proximity to the deformation-induced boundaries. The results are complementary and the measured stresses are consistent with a composite model for long-range internal stresses

  2. Three-Dimensional Finite Element Analysis of the Stress Distribution at the Internal Implant-Abutment Connection.

    Science.gov (United States)

    Cho, Sung-Yong; Huh, Yoon-Hyuk; Park, Chan-Jin; Cho, Lee-Ra

    2016-01-01

    This study investigated stress distribution in four different implant-abutment interface conditions in the internal tapered connection implant system. Four different implant diameters (3.5 mm, 4.0 mm, 4.5 mm, and 5.0 mm) and two abutment types (hexagonal and conical) were simulated. Four unique implant-abutment interface conditions were assumed based on wall thickness, mating surface length, distance to the vertical stop, and abutment shape. Axial and oblique loading was applied during abutment screw preload, and the Von Mises stresses were measured at the implant-abutment and abutment-screw interfaces. The implant-abutment interface stress decreased as the wall thickness increased. As the mating surface increased, the stress distribution trended downward, and when the distance to the implant vertical stop was 0 μm, the Von Mises stress was extremely high at the vertical stop. Despite their different shapes, the abutments showed similar stress distributions. However, the maximum Von Mises stress was higher in the conical connection than in the hexagonal connection, particularly at the contralateral side to loading. To decrease the stress distribution at the implant-abutment interface, the implant wall thickness, mating surface contact length, distance to the vertical stop, and abutment shape should be carefully considered.

  3. The Role of Distal Minority Stress and Internalized Transnegativity in Suicidal Ideation and Nonsuicidal Self-Injury Among Transgender Adults.

    Science.gov (United States)

    Staples, Jennifer M; Neilson, Elizabeth C; Bryan, Amanda E B; George, William H

    Transgender people are at elevated risk for nonsuicidal self-injury (NSSI) and suicidal ideation compared to the general population. Transgender (trans) refers to a diverse group of people who experience incongruence between their gender identity and sex assigned at birth. The present study is guided by the minority stress model and the psychological mediation framework, which postulate that sexual minority groups experience elevated stress as a result of anti-minority prejudice, contributing to negative mental health outcomes. This study utilized these theories to investigate the role of internalized transnegativity-internalization of negative societal attitudes about one's trans identity-in the relationships of distal trans stress to suicidal ideation and NSSI. A U.S. national sample of trans adults (N = 237) completed a battery of online measures. Structural equation modeling (SEM) was used to compare models with mediation and moderation effects. Results suggested that internalized transnegativity acts as both a mediator and a moderator in the relationship between distal trans stress and suicidal ideation. Log likelihood comparisons suggested moderation models had the superior fit for these data. Results suggest that clinical interventions should directly target individuals' internalized transnegativity as well as societal-level transnegativity.

  4. Early Pubertal Maturation and Internalizing Problems in Adolescence: Sex Differences in the Role of Cortisol Reactivity to Interpersonal Stress

    Science.gov (United States)

    Natsuaki, Misaki N.; Klimes-Dougan, Bonnie; Ge, Xiaojia; Shirtcliff, Elizabeth A.; Hastings, Paul D.; Zahn-Waxler, Carolyn

    2009-01-01

    An accumulating body of literature has shown a link between early pubertal maturation and internalizing problems, particularly among girls. Our knowledge is, however, limited with regard to what accounts for this association. Based on a hypothesis that early maturing girls have heightened stress sensitivity that increases the risk of internalizing…

  5. Quality of life among adolescents with sickle cell disease: Mediation of pain by internalizing symptoms and parenting stress

    Directory of Open Access Journals (Sweden)

    Daniel Lauren C

    2008-08-01

    Full Text Available Abstract Background This study aimed to clarify associations between pain, psychological adjustment, and family functioning with health-related quality of life (HRQOL in a sample of adolescents with sickle cell disease (SCD utilizing teen- and parent-report. Methods Forty-two adolescents (between the ages of 12 and 18 with SCD and their primary caregivers completed paper-and-pencil measures of pain, teen's psychological adjustment, and HRQOL. In addition, primary caregivers completed a measure of disease-related parenting stress. Medical file review established disease severity. Results Pearson correlations identified significant inverse associations of pain frequency with physical and psychosocial domains of HRQOL as rated by the teen and primary caregiver. Generally, internalizing symptoms (i.e. anxiety and depression and disease-related parenting stress were also significantly correlated with lower HRQOL. Examination of possible mediator models via a series of regression analyses confirmed that disease-related parenting stress served as a mediator between pain frequency and physical and psychosocial HRQOL. Less consistent were findings for mediation models involving internalizing symptoms. For these, parent-rated teen depression and teen anxiety served as mediators of the association of pain frequency and HRQOL. Conclusion Results are consistent with extant literature that suggests the association of pain and HRQOL and identify concomitant pain variables of internalizing symptoms and family variables as mediators. Efforts to improve HRQOL should aim to address internalizing symptoms associated with pain as well as parenting stress in the context of SCD management.

  6. Contributions to Internal Stress from Free Dislocations and from Substructure Boundaries in Dislocation Structure Formed in High Temperature Creep

    Czech Academy of Sciences Publication Activity Database

    Orlová, Alena; Dobeš, Ferdinand

    2008-01-01

    Roč. 567-568, - (2008), s. 173-176 ISSN 0255-5476. [MSMF /5./. Brno, 27.06.2007-29.06.2007] R&D Projects: GA AV ČR 1QS200410502 Institutional research plan: CEZ:AV0Z20410507 Keywords : creep * internal stress * subgrain * dislocation density Subject RIV: BM - Solid Matter Physics ; Magnetism

  7. Investigation of an Axial Fan—Blade Stress and Vibration Due to Aerodynamic Pressure Field and Centrifugal Effects

    Science.gov (United States)

    Xu, Cheng; Amano, Ryoichi Samuel; Lee, Eng Kwong

    A 1.829m (6ft) diameter industrial large flow-rate axial fan operated at 1770rpm was studied experimentally in laboratory conditions. The flow characteristics on the fan blade surfaces were investigated by measuring the pressure distributions on the blade suction and pressure surfaces and the results were discussed by comparing with analytical formulations and CFD. Flow visualizations were also performed to validate the flow characteristics near the blade surface and it was demonstrated that the flow characteristics near the fan blade surface were dominated by the centrifugal force of the fan rotation which resulted in strong three-dimensional flows. The time-dependent pressure measurement showed that the pressure oscillations on the fan blade were significantly dominated by vortex shedding from the fan blades. It was further demonstrated that the pressure distributions during the fan start-up were highly unsteady, and the main frequency variation of the static pressure was much smaller than the fan rotational frequency. The time-dependent pressure measurement when the fan operated at a constant speed showed that the magnitude of the blade pressure variation with time and the main variation frequency was much smaller than the fan rotational frequency. The pressure variations that were related to the vortex shedding were slightly smaller than the fan rotational frequency. The strain gages were used to measure the blade stress and the results were compared with FEA results.

  8. Escalating heat-stress mortality risk due to global warming in the Middle East and North Africa (MENA).

    Science.gov (United States)

    Ahmadalipour, Ali; Moradkhani, Hamid

    2018-08-01

    Climate change will substantially exacerbate extreme temperature and heatwaves. The impacts will be more intense across the Middle East and North Africa (MENA), a region mostly characterized by hot and arid climate, already intolerable for human beings in many parts. In this study, daily climate data from 17 fine-resolution Regional Climate Models (RCMs) are acquired to calculate wet-bulb temperature and investigate the mortality risk for people aged over 65 years caused by excessive heat stress across the MENA region. Spatially adaptive temperature thresholds are implemented for quantifying the mortality risk, and the analysis is conducted for the historical period of 1951-2005 and two future scenarios of RCP4.5 and RCP8.5 during the 2006-2100 period. Results show that the mortality risk will increase in distant future to 8-20 times higher than that of the historical period if no climate change mitigation is implemented. The coastal regions of the Red sea, Persian Gulf, and Mediterranean Sea indicate substantial increase in mortality risk. Nonetheless, the risk ratio will be limited to 3-7 times if global warming is limited to 2 °C. Climate change planning and adaptation is imperative for mitigating heat-related mortality risk across the region. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Treatment of stress fracture of the olecranon in throwing athletes with internal fixation through a small incision

    Directory of Open Access Journals (Sweden)

    Fujioka Hiroyuki

    2012-12-01

    Full Text Available Abstract The present study is a report of retrospective case series of stress fracture of the olecranon. Six patients presented posterior elbow pain in throwing in baseball and softball, but fracture was not diagnosed in radiographs. We detected stress fracture of the olecranon using computed tomographic (CT scan and treated the patient with internal fixation with a headless cannulated double threaded screw through a small skin incision. All patients returned to competitive level without elbow complaints after the operation. When throwing athletes present with unusual posterior elbow pain and no significant findings on radiographs, a CT scan examination should be performed. We recommend surgical treatment of internal fixation with a screw through a small skin incision, as a good option for stress fracture of the olecranon in order to allow early return to sports activity in competitive athletes.

  10. Cuticular characteristics in the detection of plant stress due to air pollution - new problems in the use of these cuticular characteristics

    International Nuclear Information System (INIS)

    Garrec, J.P.

    1994-01-01

    The foliar surface, and particularly the cuticle, is the first zone of impact of air pollutants on leaves. At the level of the cuticle, it is mainly studies on the modifications of the physico-chemical properties of the waxes that allow us to detect and estimate plant stress. However, during recent years, with modifications in the nature and level of air pollution (decrease of primary pollutants: SO 2 , HF; increase of secondary pollutants: O 2 , acid deposits; increase of nitrogen deposits; increase of organic micropollutants; appearence of global environmental problems: CO 2 , climatic change), the physiological impact on plants and in particular on the cuticle is different. For this reason, new problems have appeared and use of cuticular characteristics in the detection of plant stress due to air pollutants has recently evolved. Some examples are given, but much remains to be done to understand the effects on the cuticle of these new modifications of the atmospheric environment of plants. (orig.)

  11. Results of the regional intercomparison on internal dosimetry – 2013: Interpretation of monitoring data for effective dose assessment due to internal exposure

    International Nuclear Information System (INIS)

    Rojo, A.M.; Puerta, N.; Gossio, S.; Gómez Parada, I.

    2015-01-01

    Internal dosimetry intercomparisons are essential for the verification of the models applied and the results consistency. To that aim, the 1. Regional Intercomparison Exercise was organized in 2005 in the frame of the RLA 9/049. The results of this exercise led to the 2. Regional Intercomparison Exercise in 2013, which was organized in the frame of the RLA 9/066 and coordinated by Autoridad Regulatoria Nuclear (ARN) of Argentina. Four simulated cases covering intakes of “1”3”1I, “1”3”7Cs and Tritium were proposed. The exercise counted with the participation of 19 centres from 13 countries. This report shows a complete analysis of the participant’s results in this 2nd. exercise, useful to test their skills and acquired knowledge, particularly in applying the IDEAS guidelines. It is important to highlight the improvement in the general performance of the participants. (authors) [es

  12. Starting solutions for the flow of second grade fluids in a rectangular channel due to an oscillating shear stress

    Science.gov (United States)

    Vieru, Dumitru; Fetecau, Corina; Rana, Mehwish

    2012-05-01

    The unsteady motion of a second grade fluid between two parallel side walls perpendicular to a plate is studied by means of the Fourier sine and cosine transforms. Initially, the fluid is at rest and at time t = 0+, the plate applies an oscillating shear to the fluid. The solutions that have been obtained, presented under integral and series form and written as a sum between steady time-periodic and transient solutions can be easily reduced to the similar solutions for Newtonian fluids performing the same motion. They describe the motion of the fluid some time after its initiation. After that time, when the transient solutions disappear, the motion of the fluid is described by the steady time-periodic solutions that are independent of the initial conditions. In the absence of side walls, more exactly when the distance between walls tends to infinity, all solutions reduce to those corresponding to the motion over an infinite plate. As it was to be expected, the steady time-periodic solutions corresponding to sine and cosine oscillations of the shear stress on the boundary differ by a phase shift. Finally, the influence of side walls on the fluid motion, the required time to reach the steady periodic flow, as well as the distance between walls for which the velocity of the fluid in the middle of the channel is unaffected by their presence are established by numerical calculus and graphical illustrations. As expected, the time needed to reach the steady periodic flows is lower in the presence of side walls. It is lower for Newtonian fluids in comparison with second grade fluids and greater for sine oscillations in comparison to the cosine oscillations of the boundary shear.

  13. Induction of apoptosis by zerumbone isolated from Zingiber zerumbet (L. Smith in protozoan parasite Leishmania donovani due to oxidative stress

    Directory of Open Access Journals (Sweden)

    Debarati Mukherjee

    2016-01-01

    Full Text Available In the present context of emergence of resistance aligned with the conventional anti-leishmanial drugs and occasional treatment failure compelled us to continue the search for replaceable therapeutic leads against Leishmania infection. Various ginger spices of the Zingiberaceae family are widely used as spices, flavouring agents, and medicines in Southeast Asia because of their unique flavour as well as due to their medicinal properties. Zerumbone, a natural component of Zingiber zerumbet (L. Smith, has been studied for its pharmacological potential as antiulcer, antioxidant, anticancer, and antimicrobial. In this study, we have shown that zerumbone could induce ROS mediated apoptosis in Leishmania donovani promastigotes and also found effective in reducing intracellular amastigotes in infected-macrophages. We emphasized the potential of zerumbone to be employed in the development of new therapeutic drugs against L. donovani infection and provided the basis for future research on the application of transitional medicinal plants.

  14. Acculturation, Acculturative Stress, and Depressive Symptoms in International Migrants: A Study with Vietnamese Women in South Korea.

    Science.gov (United States)

    Cho, Yong Ju; Jang, Yuri; Ko, Jung Eun; Lee, Sun Hae; Moon, Soo Kyung

    2017-10-10

    Globally, there have been increasing numbers of migrant women; these women are at an increased risk for depressive symptoms. The purpose of this study was to examine the associations among acculturation, acculturative stress and depressive symptoms in Vietnamese women who migrated to South Korea through marriages. We hypothesized that acculturative stress would serve as a mediator in the relationship between acculturation and depressive symptoms. Our findings from surveys with 217 Vietnamese immigrant women showed that the indirect effect of acculturation on depressive symptoms, mediated through acculturative stress [- .15 (.04)], was significant (bias corrected 95% confidence interval for the indirect effect = - .25, - .08). Low levels of acculturation increased acculturative stress, which in turn led to the elevated symptoms of depression. Our findings not only illuminate the adaptation processes of international, female migrants but also suggest avenues to protect and promote their mental well-being.

  15. Preschoolers’ Genetic, Physiological, and Behavioral Sensitivity Factors Moderate Links Between Parenting Stress and Child Internalizing, Externalizing, and Sleep Problems

    Science.gov (United States)

    Davis, Molly; Thomassin, Kristel; Bilms, Joanie; Suveg, Cynthia; Shaffer, Anne; Beach, Steven R. H.

    2017-01-01

    This study examined three potential moderators of the relations between maternal parenting stress and preschoolers’ adjustment problems: a genetic polymorphism - the short allele of the serotonin transporter (5-HTTLPR, ss/sl allele) gene, a physiological indicator - children’s baseline respiratory sinus arrhythmia (RSA), and a behavioral indicator - mothers’ reports of children’s negative emotionality. A total of 108 mothers (Mage = 30.68 years, SDage = 6.06) reported on their parenting stress as well as their preschoolers’ (Mage = 3.50 years, SDage = .51, 61% boys) negative emotionality and internalizing, externalizing, and sleep problems. Results indicated that the genetic sensitivity variable functioned according to a differential susceptibility model; however, the results involving physiological and behavioral sensitivity factors were most consistent with a diathesis-stress framework. Implications for prevention and intervention efforts to counter the effects of parenting stress are discussed. PMID:28295263

  16. Finite element based stress analysis of BWR internals exposed to accident loads

    Energy Technology Data Exchange (ETDEWEB)

    Altstadt, E; Weiss, F P; Werner, M; Willschuetz, H G

    1998-10-01

    During a hypothetical accident the reactor pressure vessel internals of boiling water reactors can be exposed to considerable loads resulting from temperature gradients and pressure waves. Three dimensional FE models were developed for the core shroud, the upper and the lower core supporting structure, the steam separator pipes and the feed water distributor. The models of core shroud, upper core structure and lower core structure were coupled by means of the substructure technique. All FE models can be used for thermal and for structural mechanical analyses. As an example the FE analysis for the case of a station black-out scenario (loss of power supply for the main circulating pumps) with subsequent emergency core cooling is demonstrated. The transient temperature distributions within the core shroud and within the steam dryer pipes as well were calculated based on the fluid temperatures and the heat transfer coefficients provided by thermo-hydraulic codes. At the maximum temperature gradients in the core shroud, the mechanical stress distribution was computed in a static analysis with the actual temperature field being the load. (orig.)

  17. Consensus statement on posttraumatic stress disorder from the International Consensus Group on Depression and Anxiety.

    Science.gov (United States)

    Ballenger, J C; Davidson, J R; Lecrubier, Y; Nutt, D J; Foa, E B; Kessler, R C; McFarlane, A C; Shalev, A Y

    2000-01-01

    To provide primary care clinicians with a better understanding of management issues in posttraumatic stress disorder (PTSD) and guide clinical practice with recommendations on the appropriate management strategy. The 4 members of the International Consensus Group on Depression and Anxiety were James C. Ballenger (chair), Jonathan R. T. Davidson, Yves Lecrubier, and David J. Nutt. Other faculty invited by the chair were Edna B. Foa, Ronald C. Kessler, Alexander C. McFarlane, and Arieh Y. Shalev. The consensus statement is based on the 6 review articles that are published in this supplement and the scientific literature relevant to the issues reviewed in these articles. Group meetings were held over a 2-day period. On day 1, the group discussed the review articles and the chair identified key issues for further debate. On day 2, the group discussed these issues to arrive at a consensus view. After the group meetings, the consensus statement was drafted by the chair and approved by all attendees. PTSD is often a chronic and recurring condition associated with an increased risk of developing secondary comorbid disorders, such as depression. Selective serotonin reuptake inhibitors are generally the most appropriate choice of first-line medication for PTSD, and effective therapy should be continued for 12 months or longer. The most appropriate psychotherapy is exposure therapy, and it should be continued for 6 months, with follow-up therapy as needed.

  18. Stress

    Science.gov (United States)

    ... taking care of an aging parent. With mental stress, the body pumps out hormones to no avail. Neither fighting ... with type 1 diabetes. This difference makes sense. Stress blocks the body from releasing insulin in people with type 2 ...

  19. Simulation of the spatial stresses due to territorial land development on Yellow River Delta Nature Reserve using a GIS-based assessment model.

    Science.gov (United States)

    Zhang, Baolei; Zhang, Qiaoyun; Feng, Qingyu; Cui, Bohao; Zhang, Shumin

    2017-07-01

    This study aimed at assessing the stresses from land development in or around Yellow River Delta Nature Reserve (YRDNR) and identifying the impacted areas. Major land development types (reservoirs, pond, aquafarm, salt pan, road, residential land, industry land, farming land, and fishing land) in or around the YRDNR from 1995 to 2014 were identified using spatial data sets derived from remote sensing imageries. The spatial stresses were simulated by considering disturbance due to land development activities and accessibility of disturbance using a geographic information system based model. The stresses were then used to identify the impacted area by land development (IALD). The results indicated that main increasing land development types in the study area from 1995 to 2014 were salt pan and construction land. The 98.2% of expanded land development area and 93.7% of increased pump number showed a good control of reserve function zone on land development spread. The spatial stress values and percentages of IALD increased from 1995 to 2014, and IALD percentage exceeded 50% for both parts of YRDNR in 2014. The results of this study also provided the information that detailed planning of the YRDNR (2014-2020) could decrease the spatial stress and IALD percentage of the whole YRDNR on the condition that the area of land development activities increased by 24.4 km 2 from 2014 to 2020. Effective measures should be taken to protect such areas from being further disturbed in order to achieve the goal of a more effective conservation of the YRDNR, and attention should be paid to the disordered land development activities in or around the natural reserves.

  20. Health crises due to infectious and communicable diseases : European preparedness and response tools in an international context.

    Science.gov (United States)

    Mahy, Patrick; Collard, Jean-Marc; Gala, Jean-Luc; Herman, Philippe; Groof, Dirk De; Quoilin, Sophie; Sneyers, Myriam

    2017-06-01

    The combination of changes in eating habits, ways of living, globalisation, extensive travelling and the migration of millions of people around the world may be contributing to increased health risks. Certainly, health crises today are proving highly complex. More and more people are travelling and may carry with them unexpected virus vectors such as mosquitoes. Preparedness is challenging and there is a need for action plans to safeguard the growing at-risk population. Health crises can potentially affect a large proportion of the population and may lead to a significant increase in mortality or to an abnormally high death rate. This should be integrated into the general concept of national and international surveillance in order to provide a prepared response in the event of crisis. This paper provides an inventory of the relevant laws, guidelines and tools in Europe (and to a lesser degree, beyond), and proposes answers to the health crisis problems associated with infectious and communicable diseases. In crisis management, communication is an important factor to consider. This paper can serve as a tool for people involved in crisis preparedness.

  1. Late-Onset Massive Epistaxis due to a Ruptured Traumatic Internal Carotid Artery Aneurysm: A Case Report.

    Science.gov (United States)

    Arai, Nobuhiko; Nakamura, Akiyoshi; Tabuse, Masanao; Miyazaki, Hiromichi

    2017-01-01

    A traumatic internal carotid artery (ICA) aneurysm is rare and difficult to treat. Trapping of ICA is commonly performed owing to the difficulty of directly approaching ICA aneurysms. Recently, coiling the aneurysm itself was recommended if possible. However, it is controversial which of methods are best to completely treat aneurysm. We present the case of a 74-year-old man, who had experienced a head injury 8 years previously, with recurrent severe epistaxis. An ICA aneurysm was detected on computed tomography. The trapping and bypass was planned. However, sudden epistaxis occurred, we performed trapping to stop the bleeding and save his life. After the operation, no right ICA or aneurysm was detected. However, severe epistaxis recurred two months after the operation. In the second operation, a ligation of the common -/- external carotid artery and a severance of an ICA portion between the ophthalmic artery and the aneurysm were insufficient to stop the bleeding. This case indicates ICA trapping, even if a trapping portion is below an ophthalmic artery, is insufficient to treat an ICA aneurysm. ICA aneurysms should be suspected when a patient present with recurrent -/- massive epistaxis, who has a head injury history, even if it is far past.

  2. Risk markers of all-cause and diagnosis-specific disability pension--a prospective cohort study of individuals sickness absent due to stress-related mental disorders.

    Science.gov (United States)

    Ishtiak-Ahmed, Kazi; Perski, Aleksander; Mittendorfer-Rutz, Ellenor

    2014-08-07

    Stress-related mental disorders rank among the leading causes of sickness absence in several European countries. The aim of this study was to investigate predictors of all-cause and diagnosis-specific disability pension in sickness absentees with stress-related mental disorders. A cohort of 36304 non-retired individuals aged 16-64 years at 31.12.2004 with at-least one sickness absence spell due to stress-related mental disorders (SRMD) initiated in 2005 in Sweden was followed-up with regard to disability pension (2006-2010) by linkage of registers. Uni- and multivariate Hazard ratios (HR) with 95% Confidence Intervals, CI, were estimated using Cox regression for several risk markers. During the follow-up period, 2735 individuals (7.5%) were granted a disability pension, predominantly due to mental diagnoses (n = 2004, 73.3%). In the multivariate analyses, female sex, age exceeding 35 years, low educational level, being born in a country outside EU25 and Northern Europe, residing outside big cities, living alone, having had a long duration of the first spell due to SRMD (>90 days); mental disorders necessitating frequent specialised health care as well as comorbid somatic disorders were found to be predictive of granting disability pension. Some different patterns emerged for risk factors related to diagnosis-specific disability pension and for younger and older individuals. Several predictors could be identified as risk markers for disability pension. The variation in the effect of risk markers with regard to age and diagnosis of disability pension speaks in favour of the importance of a person-centered approach in treatment and rehabilitation.

  3. Evaluation of stress distribution due to shearing in non-oriented electrical steel by using synchrotron radiation

    Directory of Open Access Journals (Sweden)

    Yoshiaki Zaizen

    2016-05-01

    Full Text Available The influence of the shearing process on the iron loss of non-oriented electrical steels with grain sizes of 10 μm-150 μm was investigated. The deterioration ratio of iron loss was clearly smaller in sample with small grain sizes. The droop height, reflecting the amount of plastic deformation, displayed a good relationship with the deterioration of iron loss under the effect of the material grain size. To clarify the strain distribution around the sheared edge, the elastic strain in a sheet sample with the thickness of 0.30 mm and grain size of 10 μm was evaluated by using synchrotron radiation. The width of the region of elastic strain due to shearing was two or three times of the material thickness. The results of the plastic strain distribution obtained by the measurements were then used to estimate the iron loss deterioration rate in 5 mm width sheared samples. The estimated loss deteriotation coincided with the actual measured iron loss.

  4. Evaluation of stress distribution due to shearing in non-oriented electrical steel by using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Zaizen, Yoshiaki, E-mail: y-zaizen@jfe-steel.co.jp; Omura, Takeshi; Senda, Kunihiro [Steel Research Laboratory, JFE Steel Corporation, Kawasakidori 1,Mizushima, Kurashiki,712-8511 (Japan); Fukumura, Masaru [Steel Research Laboratory, JFE Steel Corporation, Kawasaki, Kanagawa 210-0855 (Japan); Toda, Hiroaki [Steel Business Planning Dept, JFE Steel Corporation, Tokyo 100-0011 (Japan)

    2016-05-15

    The influence of the shearing process on the iron loss of non-oriented electrical steels with grain sizes of 10 μm-150 μm was investigated. The deterioration ratio of iron loss was clearly smaller in sample with small grain sizes. The droop height, reflecting the amount of plastic deformation, displayed a good relationship with the deterioration of iron loss under the effect of the material grain size. To clarify the strain distribution around the sheared edge, the elastic strain in a sheet sample with the thickness of 0.30 mm and grain size of 10 μm was evaluated by using synchrotron radiation. The width of the region of elastic strain due to shearing was two or three times of the material thickness. The results of the plastic strain distribution obtained by the measurements were then used to estimate the iron loss deterioration rate in 5 mm width sheared samples. The estimated loss deteriotation coincided with the actual measured iron loss.

  5. Surgical management of morbidity due to lymphatic filariasis: the usefulness of a standardized international clinical classification of hydroceles.

    Science.gov (United States)

    Capuano, G P; Capuano, C

    2012-03-01

    The objective of this work is to evaluate the usefulness of a standardized clinical classification of hydroceles in lymphatic filariasis endemic countries to guide their surgical management. 64 patients with hydroceles were operated in 2009-2010, in Level II hospitals (WHO classification), during two visits to Fiji, by the same mobile surgical team. The number of hydroceles treated was 83. We developed and evaluated a much needed clinical classification of hydroceles based on four criteria: Type (uni/bilateral); Side (left/right); Stage of enlargement of the scrotum rated from I to VI; Grade of burial of the penis rated from 0 to 4. It lead to the conclusion that 1) A Stage I or II hydrocele, associated with Grade 0 or 1 penis burial could be considered a "Simple Hydrocele". The surgical treatment is simple with no anticipated early complication. WHO Level II of health care structure seems adapted. 2) A Stage III or IV hydrocele associated with Grade 2, 3 or 4 penis burial could be considered a "Complicated Hydrocele". The operation is longer, more complicated and the possibility of occurrence of complications seems greater. A level III health care facility would be more adapted under the normal functioning of the health system. We conclude that a standardized clinical classification of hydroceles based on the Stage of enlargement of the scrotum and the Grade of burial of the penis appears to be a useful tool to guide the decision about the level of care and the surgical technique required. We use the same classification for penoscrotal lymphoedema. A decision tree is presented for the management of hydroceles in lymphatic filariasis endemic countries which could usefully complement the "Algorithm for management of scrotal swelling" proposed by WHO in 2002. An international classification system of hydroceles would also allow standardization and facilitate study design and comparisons of their results.

  6. Internal radiation dose to the public from polonium-210 due to consumption of seafood from Bombay-harbour bay

    International Nuclear Information System (INIS)

    Bangera, V.S.; Rudran, Kamala

    1995-01-01

    Marine organisms such as fishes, molluscs and crustaceans are known to accumulate 210 Po. Distribution of 210 Po in coastal marine organisms mainly fishes and shell fishes is studied. Concentration of 210 Po obtained in muscle of common fishes (edible portion) varied from 2.10 ± 0.11 to 21.90 ± 5.00 Bq kg -1 dry muscle (for fishes like Pampus argenteus (Pomfret), Cynoglossus elongatus (sole), Rastrelliger kanagurta (mackerel), Harpodon nehereus (Bombay duck) etc. Concentration factors for 210 Po in edible portion of fish from sea water works out to 10 3 to 10 4 . Radiation dose to the public has been evaluated on the basis of daily intake of 40 g of fish (15 kg y -1 ). Committed effective dose (CED) to 210 Po due to consumption of sea food is calculated, CED varied from 2.05 x 10 -3 to 4 x 10 -2 mSv y -1 . (author). 7 refs., 3 figs., 3 tabs

  7. The VIII International Congress on Stress Proteins in Biology and Medicine: täynnä henkeä.

    Science.gov (United States)

    Bonorino, Cristina; Sistonen, Lea; Eriksson, John; Mezger, Valérie; Santoro, Gabriella; Hightower, Lawrence E

    2018-03-01

    About 150 international scientists gathered in Turku, Finland, in August of 2017 for the eighth in a series of international congresses about the roles of stress proteins in biology and medicine. The scientific theme and title of the 2017 Congress was "Stress Management Mechanisms and Pathways." The meeting covered a broad range of topics, reflecting the wide scope of the Cell Stress Society International (CSSI) and highlighting the numerous recent breakthroughs in stress response biology and medicine. The keynote lecturers included Marja Jäättelä, Richard Morimoto, Anne Bertolotti, and Peter Walter. The Executive Council of the CSSI elected new Fellows and Senior Fellows. The Spirit of Budapest Award was presented to Peter Csermely, Wolfgang Schumann, and Subhash Lakhotia in recognition of pioneering service contributions to the CSSI. The CSSI Medallion for Career Achievement was awarded to Larry Hightower and CSSI president Gabriella Santoro proclaimed Tuesday, August 15, 2017, Robert M. Tanguay Day at the congress in recognition of Robert's many years of scientific accomplishment and work on behalf of the CSSI. Additional special events were the awarding of the Ferruccio Ritossa Early Career Award to Serena Carra and the Alfred Tissières Young Investigator Award to Ayesha Murshid. As is the tradition at CSSI congresses, there were social events that included an exciting piano performance by a trio of young Finnish pianists, at the Sibelius Museum.

  8. Academic stress and positive affect: Asian value and self-worth contingency as moderators among Chinese international students.

    Science.gov (United States)

    Liao, Kelly Yu-Hsin; Wei, Meifen

    2014-01-01

    The theoretical model proposed by Berry and colleagues (Berry, 1997; Berry, Kim, Minde, & Mok, 1987) highlights the importance of identifying moderators in the acculturation process. Accordingly, the current study examined the Asian cultural value of family recognition through achievement (FRTA) and contingency of self-worth on academic competence (CSW-AC) as moderators in the association between academic stress and positive affect among Chinese international students. A total of 370 Chinese international students completed online surveys. Results from a hierarchical regression indicated that while academic stress was negatively associated with positive affect, FRTA was positively associated with positive affect. In other words, those with high academic stress reported a lower level of positive affect. However, individuals who endorsed high levels of FRTA reported a higher level of positive affect. In addition, results also revealed a significant interaction between academic stress and CSW-AC on positive affect. Thus, the study's finding supported the moderator role of CSW-AC. Simple effect analyses were conducted to examine the significant interaction. The results showed that higher levels of CSW-AC strengthened the negative association between academic stress and positive affect but lower levels of CSW-AC did not. Future research directions and implications are discussed.

  9. Relationship between parenting stress and informant discrepancies on symptoms of ADHD/ODD and internalizing behaviors in preschool children

    Science.gov (United States)

    Ni, Hsing-Chang; Liang, Sophie Hsin-Yi; Lin, Hsiang-Yuan; Lin, Chiao-Fan; Tseng, Yu-Han

    2017-01-01

    Parent and teacher ratings of child behaviors are often discrepant, and these discrepancies may be correlated with parenting stress. The present study explored whether various parenting stress factors are associated with discrepancies between parent and teacher ratings of attention-deficit/hyperactivity disorder and oppositional defiant disorder (ODD) as well as internalizing symptoms in preschool children. We recruited 299 Taiwanese preschool children (aged 4–6 years) from the community or via clinical referrals. A structural equation modeling was used to analyze the relationships among three factors derived from the Parenting Stress Index-Short Form and informant discrepancies on symptoms of inattention, hyperactivity/impulsivity, ODD, and internalizing behaviors. Scores reported by parents were higher for each of the symptoms examined than those reported by teachers, and the degree of agreement between informants ranged from low to moderate. The parental distress factor of parenting stress was associated only with parent ratings, whereas other factors of parenting stress—parent-child dysfunctional interaction and parents’ stress resulted from their child’s temperament—were correlated with both parent and teacher ratings. Only parental distress factor predicted informant discrepancies for all behavioral symptoms assessed. Our findings suggest that parental distress should be considered when parent rating scores show significant discrepancies from that of teacher rating scores. PMID:29016602

  10. Antioxidant-enzyme reaction to the oxidative stress due to alpha-cypermethrin, chlorpyriphos, and pirimicarb in tomato (Lycopersicon esculentum Mill.).

    Science.gov (United States)

    Chahid, Karim; Laglaoui, Amin; Zantar, Said; Ennabili, Abdeslam

    2015-11-01

    Tomato (Lycopersicon esculentum Mill.) becomes one of the world's foremost vegetables, and its world production and consumption have increased fairly quickly. The capacity to induce oxidative stress in tomato plant, exposed to three xenobiotics such as alpha-cypermethrin, chlorpyriphos, and pirimicarb, was investigated by the evaluation of lipid peroxidation by measuring malondialdehyde (MDA) rate; also, we studied the response of tomato to this stress by assessing the response of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione-s-transferase (GST), and glutathione reductase (GR). The effect of the insecticides was observed using four concentrations (25, 50, 75, and 100%) for germinating seeds and only the recommended concentration in agriculture (100%) for growing plants. Our results show an important accumulation of MDA, demonstrating the increase of lipid peroxidation in consequence of the excessive reactive oxygen species (ROS) production due to insecticide treatment. In response to this oxidative stress in tomato seedlings and plants, the activities of antioxidant-enzyme system were generally enhanced. The electrophoretic analysis showed also the apparition of new isoenzymes as the case for CAT and POD.

  11. Stress at the Korean Mountains: meeting report of the 8th International Workshop on the Molecular Biology of Stress Responses

    OpenAIRE

    De Maio, Antonio; Tanguay, Robert M.; Kampinga, Harm; Lee, Eunil; Kim, Chang Duck; Hightower, Lawrence

    2010-01-01

    South Korea is a country exemplified by a combination of upscale new technology and ancient mysticism. The busy streets of Seoul hustle and bustle like any large, active metropolis, yet the city's inhabitants radiate an intrinsic sense of peace, creating a timeless atmosphere. The combination of emerging technology and profound respect for the Korean culture and heritage makes this country a unique environment in which to organize a successful scientific meeting. Cell Stress Society Internati...

  12. Oxidative stress and respiratory symptoms due to human exposure to polycyclic aromatic hydrocarbons (PAHs) in Kumasi, Ghana

    International Nuclear Information System (INIS)

    Bortey-Sam, Nesta; Ikenaka, Yoshinori; Akoto, Osei; Nakayama, Shouta M.M.; Asante, Kwadwo A.; Baidoo, Elvis; Obirikorang, Christian; Saengtienchai, Aksorn; Isoda, Norikazu; Nimako, Collins

    2017-01-01

    showed a significant sex difference with higher levels of urinary OH-PAHs in females than males. - Highlights: • Human urine was collected from Kumasi to assess the risks due to PAHs exposure. • 2-OHNaphthalene (2-OHNap) was most abundant OH-PAH and higher in females than males. • Naphthalene-containing mothballs contributed significantly to urinary 2-OHNap. • Exposure to 2-OHNap significantly increased occurrence of respiratory diseases. • PAHs exposure was significantly associated lipid peroxidation or cell damage. - In addition to lipid peroxidation/cell damage, PAHs exposure increased occurrence of respiratory diseases in residents of Kumasi, Ghana.

  13. Overall bolt stress optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut......, which results in a more evenly distribution of load along the engaged thread, has a limited influence on the maximum stress due to the stress concentration at the first thread root. To further reduce the maximum stress, the transition from bolt shank to the thread must be optimized. Stress reduction...

  14. Boundary element analysis of stress due to thermal shock loading or reactor pressure vessel nozzle; Napetostna analiza pri nestacionarni termicni obremenitvi cevnega prikljucka reaktorske tlacne posode z metodo robnih elementov

    Energy Technology Data Exchange (ETDEWEB)

    Kramberger, J; Potrc, I [Tehniska fakulteta, Maribor (Yugoslavia)

    1989-07-01

    Apart from being exposed to the primary loading of internal pressure and steady temperature field, the reactor pressure vessel is also subject to various thermal transients (thermal shocks). Theoretical and experimental stress analyses show that severe material stresses occur in the nozzle area of the pressure vessel which may lead to defects (cracks). It has been our aim to evaluate these stresses by the use of the Boundary Element method. (author)

  15. Iodine stress corrosion cracking (SCC) of unirradiated Zircaloy-4 tubing by means of internal gas pressurization, (1)

    International Nuclear Information System (INIS)

    Onchi, Takeo; Inoue, Tadashi

    1982-01-01

    The internal gas pressurization tests were conducted at 360 0 C, to examine the influence of iodine concentration on the iodine stress corrosion cracking (SCC) susceptibility of Zircaloy-4 tubing of 17 x 17 type PWR design. The iodine contents studied were ranging of 0.06 to 6 mg/cm 2 , corresponding to 30 from 0.3 mg/cm 3 . Applied hoop stress vs. time-to-failure relationships were obtained in argon gas with iodine, as well as without iodine, from the tests of maximum holding times up to 72 hrs. The relationships obtained were insensitive to iodine contents. The applied stress lowering in iodine atmosphere approached a threshold stress below which SCC failure did not occur within the holding time, but not in argon gas alone. The threshold stresses were approximately 25.5 kg/mm 2 (250 Mpa), independent on iodine concentrations. Based on fracture mechanics approach and fractographic analysis, an interpretation was made of those applied stress and time-to-failure relationships. (author)

  16. Estimate of the internal doses received by the population of Bucharest due to 137 Cs and 90 Sr intake in the first five years after the Chernobyl accident

    International Nuclear Information System (INIS)

    Toader, Maria; Vasilache, R. A.

    1995-01-01

    The evolution of the 137 Cs and 90 Sr daily intake between April 1986 and March 1991 as well as the internal doses resulting from ingestion of contaminated food is presented for a group of adults living in Bucharest. The results indicate that the effective doses due to 137 Cs and 90 Sr dietary intake had the highest values in the first year after the Chernobyl accident, namely, 796 μSv as a result of 137 Cs dietary intake and 23 μSv as a result of the 90 Sr dietary intake. The effective doses committed annually due to the Caesium-137 dietary intake decreased very fast from 796 μSv committed in the first year after the accident to 7.3 μSv committed in the fifth year after the accident. Although the effective dose committed in the first year after the accident due to the Strontium-90 dietary intake was much smaller than the dose due to the Caesium-137 (23 μSv), the decrease was slower so that the effective dose committed in the fifth year after the accident due to the Strontium-90 dietary intake was 7.5 μSv. (authors)

  17. Internal electric fields due to piezoelectric and spontaneous polarizations in CdZnO/MgZnO quantum well with various applied electric field effects

    International Nuclear Information System (INIS)

    Jeon, H.C.; Lee, S.J.; Kang, T.W.; Park, S.H.

    2012-01-01

    The strain-induced piezoelectric polarization and the spontaneous polarization can be reduced effectively using the applied electric field in the CdZnO/ZnMgO quantum well (QW) structure with high Cd composition. That is, optical properties as a function of internal and external fields in the CdZnO/ZnMgO QW with various applied electric field result in the increased optical gain due to the fact that the QW potential profile is flattened as a result of the compensation of the internal field by the reverse field as confirmed. These results demonstrate that a high-performance optical device operation can be realized in CdZnO/MgZnO QW structures by reducing the droop phenomenon.

  18. Assessment of the current internal dose due to 137Cs and 90Sr for people living within the Semipalatinsk Test Site, Kazakhstan.

    Science.gov (United States)

    Semiochkina, N; Voigt, G; Mukusheva, M; Bruk, G; Travnikova, I; Strand, P

    2004-02-01

    The Semipalatinsk Test Site in Kazakhstan was one of the major sites used by the USSR for testing nuclear weapons for more than 40 y. Since the early 1990's, responsibility for the site has passed to the Kazakh authorities. There has been a gradual re-establishment of agricultural use such as horse and sheep farming. Therefore, it has become important to evaluate the current and future risk to people living on and using the contaminated area. Internal dose assessment is one of the main components of the total dose when deriving risk factors for population living within the test site. Internal doses based on food monitoring and whole body measurements were calculated for adults and are in the range of 13-500 microSv y(-1) due to radiocesium and radiostrontium.

  19. Internal electric fields due to piezoelectric and spontaneous polarizations in CdZnO/MgZnO quantum well with various applied electric field effects

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, H.C. [Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715 (Korea, Republic of); Lee, S.J., E-mail: leesj@dongguk.edu [Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715 (Korea, Republic of); Kang, T.W. [Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715 (Korea, Republic of); Park, S.H. [Department of Electronics Engineering, Catholic University of Daegu, Kyeongbuk 712-702 (Korea, Republic of)

    2012-05-15

    The strain-induced piezoelectric polarization and the spontaneous polarization can be reduced effectively using the applied electric field in the CdZnO/ZnMgO quantum well (QW) structure with high Cd composition. That is, optical properties as a function of internal and external fields in the CdZnO/ZnMgO QW with various applied electric field result in the increased optical gain due to the fact that the QW potential profile is flattened as a result of the compensation of the internal field by the reverse field as confirmed. These results demonstrate that a high-performance optical device operation can be realized in CdZnO/MgZnO QW structures by reducing the droop phenomenon.

  20. Diffusion of knowledge and urban legends: the case of internments due to sanitation conditions - DOI: 10.3395/reciis.v2i2.152en

    Directory of Open Access Journals (Sweden)

    Christovam Barcellos

    2009-03-01

    Full Text Available The statement that in Brazil “68% of the internments are due to the lack of sanitation” is diffused on the Web pages. The weight of the diseases related with water in the internment is clearly overestimated. If one considers just the hydric transmission diseases, this proportion falls to 4.8%. 204 websites of environment defense organizations and institutions, professional associations, universities and research centers quoting this statement were found upon a search on the Internet. The transmission standards of false information characterize this as one additional urban legend among those that impair the establishment of priorities. As the public policies are established from an accumulation of knowledge, the transmission of information in reports, scientific papers and texts on the Internet may represent the longing of pressure groups to alter priorities of the sanitation area.

  1. Neutron diffraction study of internal stresses in brazed CFC/Mo divertor structures for NET/ITER

    Energy Technology Data Exchange (ETDEWEB)

    Ceretti, M [Laboratoire Leon-Brillouin, CEA/CE Saclay, F-91191, Gif-sur-Yvette (France); Coppola, R [ENEA/Casaccia, INN-FIS, C.P. 2400, I-00100 Rome (Italy); Di Pietro, E [ENEA/Frascati, Dip. FUS, C.P. 2400, I-00100 Rome (Italy); Lodini, A [Laboratoire Leon-Brillouin, CEA/CE Saclay, F-91191, Gif-sur-Yvette (France) Universite de Champagne-Ardennes, Reims (France); Perrin, M [Laboratoire Leon-Brillouin, CEA/CE Saclay, F-91191, Gif-sur-Yvette (France); Piant, A [Laboratoire Leon-Brillouin, CEA/CE Saclay, F-91191, Gif-sur-Yvette (France); Rustichelli, F [Istituto di Scienze Fisiche, Universita di Ancona (Italy)

    1994-09-01

    This contribution presents the first results of a study, performed by neutron diffraction, on the internal stresses remaining after brazing at 860 C in graphite/molybdenum samples developed for NET/ITER. Samples of polycrystalline graphite and a carbon-fiber composite are considered. The deformation field is characterized close to the brazing interface, within a linear spatial resolution of approximately 2 mm. The results are discussed with reference to those obtainable by other methods and to theoretical considerations. ((orig.))

  2. Computing the stresses and deformations of the human eye components due to a high explosive detonation using fluid-structure interaction model.

    Science.gov (United States)

    Karimi, Alireza; Razaghi, Reza; Navidbakhsh, Mahdi; Sera, Toshihiro; Kudo, Susumu

    2016-05-01

    In spite the fact that a very small human body surface area is comprised by the eye, its wounds due to detonation have recently been dramatically amplified. Although many efforts have been devoted to measure injury of the globe, there is still a lack of knowledge on the injury mechanism due to Primary Blast Wave (PBW). The goal of this study was to determine the stresses and deformations of the human eye components, including the cornea, aqueous, iris, ciliary body, lens, vitreous, retina, sclera, optic nerve, and muscles, attributed to PBW induced by trinitrotoluene (TNT) explosion via a Lagrangian-Eulerian computational coupling model. Magnetic Resonance Imaging (MRI) was employed to establish a Finite Element (FE) model of the human eye according to a normal human eye. The solid components of the eye were modelled as Lagrangian mesh, while an explosive TNT, air domain, and aqueous were modelled using Arbitrary Lagrangian-Eulerian (ALE) mesh. Nonlinear dynamic FE simulations were accomplished using the explicit FE code, namely LS-DYNA. In order to simulate the blast wave generation, propagation, and interaction with the eye, the ALE formulation with Jones-Wilkins-Lee (JWL) equation defining the explosive material were employed. The results revealed a peak stress of 135.70kPa brought about by detonation upsurge on the cornea at the distance of 25cm. The highest von Mises stresses were observed on the sclera (267.3kPa), whereas the lowest one was seen on the vitreous body (0.002kPa). The results also showed a relatively high resultant displacement for the macula as well as a high variation for the radius of curvature for the cornea and lens, which can result in both macular holes, optic nerve damage and, consequently, vision loss. These results may have implications not only for understanding the value of stresses and strains in the human eye components but also giving an outlook about the process of PBW triggers damage to the eye. Copyright © 2016 Elsevier Ltd

  3. Male Asian international students' perceived racial discrimination, masculine identity, and subjective masculinity stress: a moderated mediation model.

    Science.gov (United States)

    Wong, Y Joel; Tsai, Pei-Chun; Liu, Tao; Zhu, Qingqing; Wei, Meifen

    2014-10-01

    This study examined male Asian international college students' perceptions of racial discrimination, subjective masculinity stress, centrality of masculine identity, and psychological distress by testing a moderated mediation model. Participants were 160 male Asian international college students from 2 large public universities. Participants' perceived racial discrimination was positively related to their subjective masculinity stress only at high (but not low) levels of masculine identity centrality. Additionally, subjective masculinity stress was positively related to psychological distress, although this association was stronger among those who reported high levels of masculine identity centrality. The authors also detected a moderated mediation effect in which subjective masculinity stress mediated the relationship between perceived racial discrimination and psychological distress only at high (but not low) levels of masculine identity centrality. These findings contribute to the counseling psychology literature by highlighting the connections between race- and gender-related stressors as well as the relevance of masculine identity to an understanding of men's mental health. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  4. Disordered long-range internal stresses in deformed copper and the mechanisms underlying plastic deformation

    International Nuclear Information System (INIS)

    Levine, Lyle E.; Geantil, Peter; Larson, Bennett C.; Tischler, Jonathan Z.; Kassner, Michael E.; Liu, Wenjun; Stoudt, Mark R.; Tavazza, Francesca

    2011-01-01

    Highlights: → Axial elastic strains were measured from numerous individual, contiguous dislocation cell walls and cell interiors. → The mean stresses for the cell walls and cell interiors were of opposite sign, in agreement with theoretical predictions. → The separation between the mean cell wall and cell interior stresses was about 20% of the flow stress. → Broad distributions of dipolar stresses were observed that are consistent with a simple size-scaling model. - Abstract: The strength of wavy glide metals increases dramatically during deformation as dislocations multiply and entangle, forming dense dislocation wall structures. Numerous competing models have been proposed for this process but experimental validation and guidance for further model development require new experimental approaches capable of resolving local stresses within the dislocation microstructure. We use three-dimensional X-ray microscopy combining submicrometer spatial resolution with diffracted-beam masking to make direct measurements of axial elastic strain (and thus stress) in individual dislocation cell walls and their adjacent cell interiors in heavily deformed copper. These spatially resolved measurements show broad, asymmetric distributions of dipolar stresses that directly discriminate between long-standing deformation models and demonstrate that the distribution of local stresses is statistically connected to the global behavior through simple rules.

  5. Internal stress evolution in Fe laths deformed at low temperature analysed by dislocation dynamics simulations

    International Nuclear Information System (INIS)

    Chaussidon, Julien; Fivel, Marc; Robertson, Christian; Marini, Bernard

    2010-01-01

    Stress evolution in Fe laths undergoing plastic deformation is investigated using three-dimensional dislocation dynamics simulations adapted to body centred cubic crystals, in the ductile to brittle transition temperature range. The selected boundary conditions, applied stress tensor and initial dislocation structures account for the realistic microstructure observed in bainitic steels. The effective stress field projected in the three different {1 0 0}cleavage planes is calculated for two different temperatures (50 and 200 K) and presented quantitatively, in the form of stress/frequency diagrams. It is shown that plastic activity tends to relax the stress acting in certain cleavage planes (the (0 1 0) and (0 0 1) planes) while, at the same time, amplifying the stress acting in other cleavage planes (the (1 0 0) planes). The selective stress amplification in the latter planes depends on the applied load direction, in combination with the limited set of available slip systems and the lath geometry. In the examined configuration, this selection effect is more pronounced with decreasing temperature, emphasizing the role of thermally activated plasticity on deformation-induced stress concentrations

  6. Clinical Comparison of Outcomes of Early versus Delayed Carotid Artery Stenting for Symptomatic Cerebral Watershed Infarction due to Stenosis of the Proximal Internal Carotid Artery

    Directory of Open Access Journals (Sweden)

    Huakun Liu

    2016-01-01

    Full Text Available The aim of this study was to compare the clinical outcomes of early versus delayed carotid artery stenting (CAS for symptomatic cerebral watershed infarction (sCWI patients due to stenosis of the proximal internal carotid artery. We retrospectively collected clinical data of those who underwent early or delayed CAS from March 2011 to April 2014. The time of early CAS and delayed CAS was within a week of symptom onset and after four weeks from symptom onset. Clinical data such as second stroke, the National Institutes of Health Stroke Scale (NHISS score, and modified Rankin Scale (mRS score and periprocedural complications were collected. The rate of second stroke in early CAS group is lower when compared to that of delayed CAS group. There was no significant difference regarding periprocedural complications in both groups. There was a significant difference regarding mean NHISS score 90 days after CAS in two groups. Early CAS group had a significant better good outcome (mRS score ≤ 2 than delayed CAS group. We suggest early CAS for sCWI due to severe proximal internal carotid artery stenosis as it provides lower rate of second stroke, comparable periprocedural complications, and better functional outcomes compared to that of delayed CAS.

  7. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  8. Stress !!!

    OpenAIRE

    Fledderus, M.

    2012-01-01

    Twee op de vijf UT-studenten hebben last van ernstige studiestress, zo erg zelfs dat het ze in hun privéleven belemmert. Die cijfers komen overeen met het landelijk beeld van stress onder studenten. Samen met 14 andere universiteits- en hogeschoolbladen enquêteerde UT Nieuws bijna 5500 studenten. Opvallend is dat mannelijke studenten uit Twente zich veel minder druk lijken te maken over hun studie. Onder vrouwen ligt de stress juist erg hoog ten opzichte van het landelijk gemiddelde.

  9. Using single-step genomic best linear unbiased predictor to enhance the mitigation of seasonal losses due to heat stress in pigs.

    Science.gov (United States)

    Fragomeni, B O; Lourenco, D A L; Tsuruta, S; Bradford, H L; Gray, K A; Huang, Y; Misztal, I

    2016-12-01

    The purposes of this study were to analyze the impact of seasonal losses due to heat stress in pigs from different breeds raised in different environments and to evaluate the accuracy improvement from adding genomic information to genetic evaluations. Data were available for 2 different swine populations: purebred Duroc animals raised in Texas and North Carolina and commercial crosses of Duroc and F females (Landrace × Large White) raised in Missouri and North Carolina; pedigrees provided links for animals from different states. Pedigree information was available for 553,442 animals, of which 8,232 pure breeds were genotyped. Traits were BW at 170 d for purebred animals and HCW for crossbred animals. Analyses were done with an animal model as either single- or 2-trait models using phenotypes measured in different states as separate traits. Additionally, reaction norm models were fitted for 1 or 2 traits using heat load index as a covariable. Heat load was calculated as temperature-humidity index greater than 70 and was averaged over 30 d prior to data collection. Variance components were estimated with average information REML, and EBV and genomic EBV (GEBV) with BLUP or single-step genomic BLUP (ssGBLUP). Validation was assessed for 146 genotyped sires with progeny in the last generation. Accuracy was calculated as a correlation between EBV and GEBV using reduced data (all animals, except the last generation) and using complete data. Heritability estimates for purebred animals were similar across states (varying from 0.23 to 0.26), and reaction norm models did not show evidence of a heat stress effect. Genetic correlations between states for heat loads were always strong (>0.91). For crossbred animals, no differences in heritability were found in single- or 2-trait analysis (from 0.17 to 0.18), and genetic correlations between states were moderate (0.43). In the reaction norm for crossbreeds, heritabilities ranged from 0.15 to 0.30 and genetic correlations

  10. Latin America multidisciplinary research on heat shock proteins and cell stress: proceedings of the first conference of the Latin America Chapter of the Cell Stress Society International.

    Science.gov (United States)

    Bausero, María A

    2015-09-01

    The First Conference of the Latin America Chapter of the Cell Stress Society International (CSSI) organized by CSSI was held in Montevideo, Uruguay, on March 11-14, 2014. The Latin America Chapter of the CSSI (LAC-CSSI) was established at the Workshop on the Molecular Biology of the Stress Response, Porto Alegre, Brazil, May 2012. The chapter's first meeting took place in the beautiful city of Montevideo and was chaired by the first (LAC-CSSI) elected president Professor María Bausero. Forty-two invited speakers presented their work to more than 100 scientists. The first day of the conference was dedicated to an introductory program for students, young investigators, and participants new to the field of molecular chaperones and the stress response. These seminars were held in the Pasteur Institute of Montevideo and the Faculty of Sciences of the University of the Republic. These institutions were carefully selected to give foreign participants a broad view of the diversity of students and institutions doing research in Uruguay, as well as an opportunity for direct interaction with our scientists and students. Invited speakers for the seminar series were Dr. Wolfgang Schumann, Dr. Cristina Bonorino, Dr. Antonio De Maio, Dr. Ian Brown, Dr. Rafael Radi, Dr. Daniel Ciocca, and Dr. Celia Quijano. The remaining days of the conference took place at the Sheraton Hotel in Montevideo, and the scientific sessions are discussed below.

  11. Effects of neutron radiation and residual stresses on the corrosion of welds in light water reactor internals

    International Nuclear Information System (INIS)

    Schaaf, Bob van der; Gavillet, Didier; Lapena, Jesus; Ohms, Carsten; Roth, Armin; Dyck, Steven van

    2006-01-01

    After many years of operation in Light Water Reactors (LWR) Irradiation Assisted Stress Corrosion Cracking (IASCC) of internals has been observed. In particular the heat-affected zone (HAZ) has been associated with IASCC attack. The welding process induces residual stresses and micro-structural modifications. Neutron irradiation affects the materials response to mechanical loading. IASCC susceptibility of base materials is widely studied, but the specific conditions of irradiated welds are rarely assessed. Core component relevant welds of Type 304 and 347 steels have been fabricated and were irradiated in the High Flux Reactor (HFR) in Petten to 0.3 and 1 dpa (displacement per atom). In-service welds were cut from the thermal shield of the decommissioned BR-3 reactor. Residual stresses, measured using neutron diffraction, ring core tests and X-ray showed residual stress levels up to 400 MPa. Micro-structural characterization showed higher dislocation densities in the weld and HAZ. Neutron radiation increased the dislocation density, resulting in hardening and reduced fracture toughness. The sensitization degree of the welds, measured with the electrochemical potentio-dynamic reactivation method, was negligible. The Slow Strain Rate Tensile (SSRT) tests, performed at 290 deg. C in water with 200 ppb dissolved oxygen, (DO), did not reveal inter-granular cracking. Inter-granular attack of in-service steel is observed in water with 8 ppm (DO), attributed not only to IASCC, but also to IGSCC from thermal sensitization during fabrication. Stress-relieve annealing has caused Cr-grain boundary precipitation, indicating the sensitization. The simulated internal welds, irradiated up to 1.0 dpa, did not show inter-granular cracking with 8 ppm DO. (authors)

  12. Discrete element simulation of internal stress in SiCp/aluminum ...

    African Journals Online (AJOL)

    2002-07-22

    Jul 22, 2002 ... microcosmic two-dimensional numerical model of SiCp / Al matrix composites was established and the simulation of the size ... In the metal matrix composite ... stress and strain distribution, strengthen mechanisms and overall ...

  13. Lithospheric flexure under the Hawaiian volcanic load: Internal stresses and a broken plate revealed by earthquakes

    Science.gov (United States)

    Klein, Fred W.

    2016-01-01

    Several lines of earthquake evidence indicate that the lithospheric plate is broken under the load of the island of Hawai`i, where the geometry of the lithosphere is circular with a central depression. The plate bends concave downward surrounding a stress-free hole, rather than bending concave upward as with past assumptions. Earthquake focal mechanisms show that the center of load stress and the weak hole is between the summits of Mauna Loa and Mauna Kea where the load is greatest. The earthquake gap at 21 km depth coincides with the predicted neutral plane of flexure where horizontal stress changes sign. Focal mechanism P axes below the neutral plane display a striking radial pattern pointing to the stress center. Earthquakes above the neutral plane in the north part of the island have opposite stress patterns; T axes tend to be radial. The M6.2 Honomu and M6.7 Kiholo main shocks (both at 39 km depth) are below the neutral plane and show radial compression, and the M6.0 Kiholo aftershock above the neutral plane has tangential compression. Earthquakes deeper than 20 km define a donut of seismicity around the stress center where flexural bending is a maximum. The hole is interpreted as the soft center where the lithospheric plate is broken. Kilauea's deep conduit is seismically active because it is in the ring of maximum bending. A simplified two-dimensional stress model for a bending slab with a load at one end yields stress orientations that agree with earthquake stress axes and radial P axes below the neutral plane. A previous inversion of deep Hawaiian focal mechanisms found a circular solution around the stress center that agrees with the model. For horizontal faults, the shear stress within the bending slab matches the slip in the deep Kilauea seismic zone and enhances outward slip of active flanks.

  14. Prevalence of Post-Traumatic Stress Disorder Due to Community Violence Among University Students in the World's Most Dangerous Megacity: A Cross-Sectional Study From Pakistan.

    Science.gov (United States)

    Khan, Abdul Ahad; Haider, Ghani; Sheikh, Maryam Rahim; Ali, Ambreen Fatima; Khalid, Zain; Tahir, Muhammad Munaim; Malik, Tayyaba Maqbool; Salick, Muhammad Musa; Lakhani, Laila Saleem; Yousuf, Fatimah Sireen; Khan, Muhammad Babar; Saleem, Sarah

    2016-08-01

    Community violence among the youth can lead to a number of adverse psychiatric outcomes including post-traumatic stress disorder (PTSD). However, little research has been conducted in non-Western countries to assess this problem. This study aims to fill the void by assessing the lifetime exposure to traumatic events and burden of probable PTSD among university students in Karachi, Pakistan. A cross-sectional study was conducted at four private institutions in Karachi. Self-administered questionnaires were filled out by 320 students. Lifetime exposure and symptoms of PTSD were assessed using modified Composite International Diagnostic Interview (CIDI) and Post-Traumatic Stress Disorder Checklist-Civilian Version (PCL-C) questionnaires, respectively. A PCL-C score of 44 or above was used as cutoff for probable PTSD. Pearson chi-square test was used to assess the association between PTSD and different variables at a level of significance of 5%. Ninety-three percent of the respondents reported having lifetime exposure to at least one traumatic event with sudden unexpected death of a loved one (n = 187) and assaultive violence (n = 169) being the commonest reported traumatic events. Positive association for PTSD was seen with enduring physical attacks and motor vehicle accidents. Over a quarter of the students screened positive for probable PTSD, among them almost one third were male and 17% were female. Our results indicate a high exposure to violent events and elevated rates of lifetime PTSD among urban youth. Reduction in violence and better access to mental health facilities is warranted to decrease the health burden of PTSD in Pakistan. © The Author(s) 2015.

  15. Cerebrovascular/cardiovascular diseases and mental disorders due to overwork and work-related stress among local public employees in Japan.

    Science.gov (United States)

    Yamauchi, Takashi; Yoshikawa, Toru; Sasaki, Takeshi; Matsumoto, Shun; Takahashi, Masaya; Suka, Machi; Yanagisawa, Hiroyuki

    2018-02-07

    In Japan, overwork-related disorders occur among local public employees as well as those in private businesses. However, to date, there are no studies reporting the state of compensation for cerebrovascular/cardiovascular diseases (CCVD) and mental disorders due to overwork or work-related stress among local public employees in Japan over multiple years. This report examined the recent trend of overwork-related CCVD and mental disorders, including the incidence rates of these disorders, among local public employees in Japan from the perspective of compensation for public accidents, using data from the Japanese Government and relevant organizations. Since 2000, compared to CCVD, there has been an overall increase in the number of claims and cases of compensation for mental disorders. Over half of the individuals receiving compensation for mental disorders were either in their 30s or younger. About 47% of cases of mental disorders were compensated due to work-related factors other than long working hours. The incidence rate by job type was highest among "police officials" and "fire department officials" for compensated CCVD and mental disorders cases, respectively. Changes in the trend of overwork-related disorders among local public employees in Japan under a legal foundation should be closely monitored.

  16. Three-Dimensional Finite Element Analysis on Stress Distribution of Internal Implant-Abutment Engagement Features.

    Science.gov (United States)

    Cho, Sung-Yong; Huh, Yun-Hyuk; Park, Chan-Jin; Cho, Lee-Ra

    To investigate the stress distribution in an implant-abutment complex with a preloaded abutment screw by comparing implant-abutment engagement features using three-dimensional finite element analysis (FEA). For FEA modeling, two implants-one with a single (S) engagement system and the other with a double (D) engagement system-were placed in the human mandibular molar region. Two types of abutments (hexagonal, conical) were connected to the implants. Different implant models (a single implant, two parallel implants, and mesial and tilted distal implants with 1-mm bone loss) were assumed. A static axial force and a 45-degree oblique force of 200 N were applied as the sum of vectors to the top of the prosthetic occlusal surface with a preload of 30 Ncm in the abutment screw. The von Mises stresses at the implant-abutment and abutment-screw interfaces were measured. In the single implant model, the S-conical abutment type exhibited broader stress distribution than the S-hexagonal abutment. In the double engagement system, the stress concentration was high in the lower contact area of the implant-abutment engagement. In the tilted implant model, the stress concentration point was different from that in the parallel implant model because of the difference in the bone level. The double engagement system demonstrated a high stress concentration at the lower contact area of the implant-abutment interface. To decrease the stress concentration, the type of engagement features of the implant-abutment connection should be carefully considered.

  17. Pars plana vitrectomy combined with internal limiting membrane peeling for recurrent macular edema due to branch retinal vein occlusion after antivascular endothelial growth factor treatments

    Directory of Open Access Journals (Sweden)

    Shirakata Y

    2016-02-01

    Full Text Available Yukari Shirakata,1 Kouki Fukuda,1 Tomoyoshi Fujita,1 Yuki Nakano,1 Hiroyuki Nomoto,2 Hidetaka Yamaji,3 Fumio Shiraga,4 Akitaka Tsujikawa1 1Department of Ophthalmology, Faculty of Medicine, Kagawa University, Miki-cho, 2Nomoto Eye Clinic, Himeji, 3Department of Ophthalmology, Shirai Eye Hospital, Mitoyo, 4Department of Ophthalmology, Okayama University, Okayama, Japan Purpose: To evaluate the anatomic and functional outcomes of pars plana vitrectomy combined with internal limiting membrane peeling for recurrent macular edema (ME due to branch retinal vein occlusion (BRVO after intravitreal injections of antivascular endothelial growth factor (anti-VEGF agents. Methods: Twenty-four eyes of 24 patients with treatment-naive ME from BRVO were treated with intravitreal injections of anti-VEGF agents. Recurred ME was treated with pars plana vitrectomy combined with internal limiting membrane peeling. Results: After the surgery, ME was significantly reduced at 1 month (P=0.031 and the reduction increased with time (P=0.007 at the final visit. With the reduction in ME, treated eyes showed a slow improvement in visual acuity (VA. At the final visit, improvement in VA was statistically significant compared with baseline (P=0.048. The initial presence of cystoid spaces, serous retinal detachment, or subretinal hemorrhage under the fovea, as well as retinal perfusion status, showed no association with VA improvement. However, the presence of epiretinal membrane showed a significant association with the visual recovery. Although eyes without epiretinal membrane showed visual improvement (-0.10±0.32 in logarithm of the minimum angle of resolution [logMAR], eyes with epiretinal membrane showed greater visual improvement (-0.38±0.12 in logMAR, P=0.012. Conclusion: For recurrent ME due to BRVO after anti-VEGF treatment, particularly when accompanied by epiretinal membrane, pars plana vitrectomy combined with internal limiting membrane peeling might be a

  18. Measurement of the internal stress and electric field in a resonating piezoelectric transformer for high-voltage applications using the electro-optic and photoelastic effects.

    Science.gov (United States)

    VanGordon, James A; Kovaleski, Scott D; Norgard, Peter; Gall, Brady B; Dale, Gregory E

    2014-02-01

    The high output voltages from piezoelectric transformers are currently being used to accelerate charged particle beams for x-ray and neutron production. Traditional methods of characterizing piezoelectric transformers (PTs) using electrical probes can decrease the voltage transformation ratio of the device due to the introduction of load impedances on the order of hundreds of kiloohms to hundreds of megaohms. Consequently, an optical diagnostic was developed that used the photoelastic and electro-optic effects present in piezoelectric materials that are transparent to a given optical wavelength to determine the internal stress and electric field. The combined effects of the piezoelectric, photoelastic, and electro-optic effects result in a time-dependent change the refractive indices of the material and produce an artificially induced, time-dependent birefringence in the piezoelectric material. This induced time-dependent birefringence results in a change in the relative phase difference between the ordinary and extraordinary wave components of a helium-neon laser beam. The change in phase difference between the wave components was measured using a set of linear polarizers. The measured change in phase difference was used to calculate the stress and electric field based on the nonlinear optical properties, the piezoelectric constitutive equations, and the boundary conditions of the PT. Maximum stresses of approximately 10 MPa and electric fields of as high as 6 kV/cm were measured with the optical diagnostic. Measured results were compared to results from both a simple one-dimensional (1D) model of the piezoelectric transformer and a three-dimensional (3D) finite element model. Measured stresses and electric fields along the length of an operating length-extensional PT for two different electrical loads were within at least 50 % of 3D finite element simulated results. Additionally, the 3D finite element results were more accurate than the results from the 1D model

  19. Measurement of the internal stress and electric field in a resonating piezoelectric transformer for high-voltage applications using the electro-optic and photoelastic effects

    Energy Technology Data Exchange (ETDEWEB)

    VanGordon, James A.; Kovaleski, Scott D., E-mail: kovaleskis@missouri.edu; Norgard, Peter; Gall, Brady B. [Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211 (United States); Dale, Gregory E. [High Power Electrodynamics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-02-15

    The high output voltages from piezoelectric transformers are currently being used to accelerate charged particle beams for x-ray and neutron production. Traditional methods of characterizing piezoelectric transformers (PTs) using electrical probes can decrease the voltage transformation ratio of the device due to the introduction of load impedances on the order of hundreds of kiloohms to hundreds of megaohms. Consequently, an optical diagnostic was developed that used the photoelastic and electro-optic effects present in piezoelectric materials that are transparent to a given optical wavelength to determine the internal stress and electric field. The combined effects of the piezoelectric, photoelastic, and electro-optic effects result in a time-dependent change the refractive indices of the material and produce an artificially induced, time-dependent birefringence in the piezoelectric material. This induced time-dependent birefringence results in a change in the relative phase difference between the ordinary and extraordinary wave components of a helium-neon laser beam. The change in phase difference between the wave components was measured using a set of linear polarizers. The measured change in phase difference was used to calculate the stress and electric field based on the nonlinear optical properties, the piezoelectric constitutive equations, and the boundary conditions of the PT. Maximum stresses of approximately 10 MPa and electric fields of as high as 6 kV/cm were measured with the optical diagnostic. Measured results were compared to results from both a simple one-dimensional (1D) model of the piezoelectric transformer and a three-dimensional (3D) finite element model. Measured stresses and electric fields along the length of an operating length-extensional PT for two different electrical loads were within at least 50 % of 3D finite element simulated results. Additionally, the 3D finite element results were more accurate than the results from the 1D model

  20. Acculturative Stress and Disengagement: Learning from the Adjustment Challenges Faced by East Asian International Graduate Students

    Science.gov (United States)

    Lyken-Segosebe, D. E.

    2017-01-01

    International graduate students meet TOEFL, GPA, and other admissions criteria to gain entry into US colleges and universities. During their stay in the USA, they provide educational and economic contributions for their host country. In contrast to their educational and economic potential, international students often demonstrate poor academic and…

  1. Validation of Weld Residual Stress Modeling in the NRC International Round Robin Study

    International Nuclear Information System (INIS)

    Mullins, Jonathan; Gunnars, Jens

    2013-01-01

    Weld residual stresses (WRS) have a large influence on the behavior of cracks growing under normal operation loads and on the leakage flow from a through-wall crack. Accurate prediction on weld residual stresses is important to make proper decisions when cracks in weld joints are detected. During the latest years, there has been a strong development in both analytical procedures to numerically determine WRS and experimental measurements of WRS. The USNRC (United States Nuclear Regulatory Commission) has formed a program for validation of WRS predictions through comparison of numerically calculated residual stress fields in dissimilar welds measured by different methods. The present report describes the results of the project with special focus on the contribution from Inspecta Technology. Objectives: The principal objective of the project is to compare different WRS predictions for a dissimilar pipe weld with careful measurements on a mock-up weld. The results of the project will make it possible to make recommendations on computational procedures for WRS in dissimilar metal welds. Results: It is concluded that numerical analysis of weld residual stresses using the finite element method is very useful for the estimation of weld residual stresses in complex geometries and dissimilar metal welds. The validation study increases the understanding of uncertainties associated with different modeling approaches and helps to identify the most sensitive parameters

  2. Internal Stress Distribution Measurement of TIG Welded SUS304 Samples Using Neutron Diffraction Technique

    Science.gov (United States)

    Muslih, M. Refai; Sumirat, I.; Sairun; Purwanta

    2008-03-01

    The distribution of residual stress of SUS304 samples that were undergone TIG welding process with four different electric currents has been measured. The welding has been done in the middle part of the samples that was previously grooved by milling machine. Before they were welded the samples were annealed at 650 degree Celsius for one hour. The annealing process was done to eliminate residual stress generated by grooving process so that the residual stress within the samples was merely produced from welding process. The calculation of distribution of residual stress was carried out by measuring the strains within crystal planes of Fe(220) SUS304. Strain, Young modulus, and Poisson ratio of Fe(220) SUS304 were measured using DN1-M neutron diffractometer. Young modulus and Poisson ratio of Fe(220) SUS304 sample were measured in-situ. The result of calculations showed that distribution of residual stress of SUS304 in the vicinity of welded area is influenced both by treatments given at the samples-making process and by the electric current used during welding process.

  3. Comparison in stress of caring mothers of children with developmental, external and internal disorders and normal children

    Directory of Open Access Journals (Sweden)

    Narges Zamani

    2017-06-01

    Full Text Available However, having a baby brings positive emotions such as happiness, sense of maturity and proud, parenting's issue could cause high level of stress and child's characteristics was a detrimental factor which can effect on parent's stress, so the aim of this research was comparison of stress of caring in mothers of children with developmental, external, and internal disorders and normal children. The study population included all mothers of children with developmental, emotional, and disruptive behavior disorders, and mothers with normal children in Hamadan (a city in Iran. 240 mothers (4 groups include 60 mothers were chosen based on simple random sampling. Family inventory of life events and changes Mc Cubbin, Patterson & Wilson was used for assessing participants. The results showed that maternal stress in mothers with children who have diagnosis of disruptive behavior disorders were significantly more than of mothers of children with developmental disorders, emotional and mothers of normal children. The present study showed that disruptive behavior disorders in children have a greater impact on their mothers. So, we suggest approved psychological interventions for helping mothers of children with psychological problems, particularly children with external disorders.

  4. Preschoolers' genetic, physiological, and behavioral sensitivity factors moderate links between parenting stress and child internalizing, externalizing, and sleep problems.

    Science.gov (United States)

    Davis, Molly; Thomassin, Kristel; Bilms, Joanie; Suveg, Cynthia; Shaffer, Anne; Beach, Steven R H

    2017-05-01

    This study examined three potential moderators of the relations between maternal parenting stress and preschoolers' adjustment problems: a genetic polymorphism-the short allele of the serotonin transporter (5-HTTLPR, ss/sl allele) gene, a physiological indicator-children's baseline respiratory sinus arrhythmia (RSA), and a behavioral indicator-mothers' reports of children's negative emotionality. A total of 108 mothers (M age  = 30.68 years, SD age  = 6.06) reported on their parenting stress as well as their preschoolers' (M age  = 3.50 years, SD age  = 0.51, 61% boys) negative emotionality and internalizing, externalizing, and sleep problems. Results indicated that the genetic sensitivity variable functioned according to a differential susceptibility model; however, the results involving physiological and behavioral sensitivity factors were most consistent with a diathesis-stress framework. Implications for prevention and intervention efforts to counter the effects of parenting stress are discussed. © 2017 Wiley Periodicals, Inc.

  5. Internal stress relaxation and load redistribution during the twinning-detwinning-dominated cyclic deformation of a wrought magnesium alloy, ZK60A

    International Nuclear Information System (INIS)

    Wu, L.; Agnew, S.R.; Brown, D.W.; Stoica, G.M.; Clausen, B.; Jain, A.; Fielden, D.E.; Liaw, P.K.

    2008-01-01

    A study of the internal strain (stress) evolution during cyclic deformation dominated by {101-bar2} twinning and detwinning mechanisms within a magnesium alloy, ZK60A, was conducted using in situ neutron diffraction. It is shown that once the matrix grains twin, the (00.2) matrix and twin grains are relaxed relative to the neighbors. This load redistribution between the soft- and hard-grain orientations is a result of plastic anisotropy. The twins which formed during the initial compression sustain a tensile stress along the c-axis, when the applied compressive stress is less than ∼80 MPa upon unloading. This local (intergranular) tensile stress is hypothesized to be effective for driving the detwinning event under a macroscopic compressive field along the c-axis. The activation stresses, 15 and 6 MPa, respectively, for the {101-bar2} extension twinning and detwinning, are approximated, based on the relaxation of the internal stresses in the matrix and twin grains

  6. Stress analysis in pipelines submitted to internal pressure - and temperature transients

    International Nuclear Information System (INIS)

    Mansur, T.R.

    1981-08-01

    Experimental determination of the structural behaviour of a thermal-hydraulic loop, when submitted to simultaneous fast change of pressure and temperature, was performed. For this, electrical strain-gages were positioned at some critical points in order to measure the deformation conditions of the structure. The study of the kinetics of the deformation revealed the presence of important transient stresses, mainly from thermal origin. After this transient behaviour, the structure is submitted to a thermal stress, which is shown to be strongly dependent on the degree of restraint of the structure. (Author) [pt

  7. Internal damping due to dislocation movements induced by thermal expansion mismatch between matrix and particles in metal matrix composites. [Al/SiC

    Energy Technology Data Exchange (ETDEWEB)

    Girand, C.; Lormand, G.; Fougeres, R.; Vincent, A. (GEMPPM, Villeurbanne (France))

    1993-05-01

    In metal matrix composites (MMCs), the mechanical 1 of the reinforcement-matrix interface is an important parameter because it governs the load transfer from matrix to particles, from which the mechanical properties of these materials are derived. Therefore, it would be useful to set out an experimental method able to characterize the interface and the adjacent matrix behaviors. Thus, a study has been undertaken by means of internal damping (I.D.) measurements, which are well known to be very sensitive for studying irreversible displacements at the atomic scale. More especially, this investigation is based on the fact that, during cooling of MMC's, stress concentrations originating from differences in coefficients of thermal expansion (C.T.E.) of matrix and particles should induce dislocation movements in the matrix surrounding the reinforcement; that is, local microplastic strains occur. Therefore, during I.D. measurements vs temperature these movements should contribute to MMCs I.D. in a process similar to those involved around first order phase transitions in solids. The aim of this paper is to present, in the case of Al/SiC particulate composites, new developments of this approach that has previously led to promising results in the case of Al-Si alloys.

  8. X-ray microbeam measurements of long-range internal stresses in commercial-purity aluminum processed by multiple passes of equal-channel angular pressing

    International Nuclear Information System (INIS)

    Phan, Thien Q.; Lee, I-Fang; Levine, Lyle E.; Tischler, Jonathan Z.; Huang, Yi; Fox, Alan G.; Langdon, Terence G.; Kassner, Michael E.

    2014-01-01

    X-ray microbeam diffraction was used to measure long-range internal stresses (LRISs) in the grain/subgrain interiors of commercial-purity aluminum processed by equal-channel angular pressing for up to eight passes. The LRIS values at +4.9° off the axial (pressing) direction show only a slight increase with increasing numbers of passes. The normalized stress remains approximately constant at ∼0.10 of the flow stress

  9. The Effectiveness of Mentoring Youth with Externalizing and Internalizing Behavioral Problems on Youth Outcomes and Parenting Stress: A Meta-Analysis

    Science.gov (United States)

    La Valle, Chelsea

    2015-01-01

    Parents of children with significant externalizing and internalizing behavioral problems habitually report greater parenting stress compared to parents of children without these challenges. One avenue to alleviate parenting stress and ameliorate youth outcomes is youth mentoring, which includes a supportive adult paired with a child with the…

  10. Stress !!!

    NARCIS (Netherlands)

    Fledderus, M.

    2012-01-01

    Twee op de vijf UT-studenten hebben last van ernstige studiestress, zo erg zelfs dat het ze in hun privéleven belemmert. Die cijfers komen overeen met het landelijk beeld van stress onder studenten. Samen met 14 andere universiteits- en hogeschoolbladen enquêteerde UT Nieuws bijna 5500 studenten.

  11. Getting under the skin: Report from the International Psoriasis Council workshop on the role of stress in psoriasis

    Directory of Open Access Journals (Sweden)

    Julia eSchwartz

    2016-02-01

    Full Text Available Psoriasis is a chronic inflammatory skin condition with significant physical and psychosocial comorbidity. A workshop of leading experts in dermatology and psychology with the purpose of better understanding the current role of psychological comorbidities in psoriasis was held by the International Psoriasis Council in November 2013. The role of stress reactivity with a focus on the hypothalamic-pituitary-adrenal axis was emphasized. While cognitive behavioral therapy remains the most extensively studied and successful treatment strategy in patients with psoriasis and various psychological comorbidities, new and innovative interventions such as online-based therapies have recently emerged. Strategies and recommendations towards approaching psychological comorbidities are discussed.

  12. The Internal Stress Evaluation of Pultruded Blades for a Darrieus Wind Turbine

    DEFF Research Database (Denmark)

    Baran, Ismet; Tutum, Cem Celal; Hattel, Jesper Henri

    2013-01-01

    This paper investigates the integrated modeling of a pultruded NACA0018 blade profile which is a part of the FP7 EU project DeepWind. The pultrusion process simulation is combined with the preliminary subsequent in-service load scenario. In particular, the process induced residual stresses...

  13. The Internal Stress Evaluation of Pultruded Blades for a Darrieus Wind Turbine

    NARCIS (Netherlands)

    Baran, Ismet; Tutum, Cem C.; Hattel, Jesper Henri

    2013-01-01

    This paper investigates the integrated modeling of a pultruded NACA0018 blade profile which is a part of the FP7 EU project DeepWind. The pultrusion process simulation is combined with the preliminary subsequent in-service load scenario. In particular, the process induced residual stresses and

  14. Dislocation structures, effective and internal stresses of cyclic stained ferritic stainless steel

    Czech Academy of Sciences Publication Activity Database

    Petrenec, Martin; Polák, Jaroslav

    2001-01-01

    Roč. 72, č. 279 (2001), s. 129-133 ISSN 1429-6055. [Medzynarodowe Sympozjum - Metody oceny struktury oraz wlasnosci materialów i wyrobów /16./. Komorní Lhotka, 11.12.2001-13.12.2001] Institutional research plan: CEZ:AV0Z2041904 Keywords : dislocation * cyclicling * stresses Subject RIV: JL - Materials Fatigue, Friction Mechanics

  15. Raman Microscopic Analysis of Internal Stress in Boron-Doped Diamond

    Directory of Open Access Journals (Sweden)

    Kevin E. Bennet

    2015-05-01

    Full Text Available Analysis of the induced stress on undoped and boron-doped diamond (BDD thin films by confocal Raman microscopy is performed in this study to investigate its correlation with sample chemical composition and the substrate used during fabrication. Knowledge of this nature is very important to the issue of long-term stability of BDD coated neurosurgical electrodes that will be used in fast-scan cyclic voltammetry, as potential occurrence of film delaminations and dislocations during their surgical implantation can have unwanted consequences for the reliability of BDD-based biosensing electrodes. To achieve a more uniform deposition of the films on cylindrically-shaped tungsten rods, substrate rotation was employed in a custom-built chemical vapor deposition reactor. In addition to visibly preferential boron incorporation into the diamond lattice and columnar growth, the results also reveal a direct correlation between regions of pure diamond and enhanced stress. Definite stress release throughout entire film thicknesses was found in the current Raman mapping images for higher amounts of boron addition. There is also a possible contribution to the high values of compressive stress from sp2 type carbon impurities, besides that of the expected lattice mismatch between film and substrate.

  16. Soldiers Working Internationally: Impacts of Masculinity, Military Culture, and Operational Stress on Cross-Cultural Adaptation

    Science.gov (United States)

    Keats, Patrice A.

    2010-01-01

    This paper explores the ramifications of masculinized military culture and operational stress on cross-cultural adaptation. The author examines how characteristics of military culture may obstruct effective cross-cultural adaptation by promoting a hypermasculinity that tends to oppose effective management of trauma, and thereby suppresses skills…

  17. Transgenic mice overexpressing glia maturation factor-β, an oxidative stress inducible gene, show premature aging due to Zmpste24 down-regulation.

    Science.gov (United States)

    Imai, Rika; Asai, Kanae; Hanai, Jun-ichi; Takenaka, Masaru

    2015-07-01

    Glia Maturation Factor-β (GMF), a brain specific protein, is induced by proteinuria in renal tubules. Ectopic GMF overexpression causes apoptosisin vitro via cellular vulnerability to oxidative stress. In order to examine the roles of GMF in non-brain tissue, we constructed transgenic mice overexpressing GMF (GMF-TG). The GMF-TG mice exhibited appearance phenotypes associated with premature aging. The GMF-TG mice also demonstrated short lifespans and reduced hair regrowth, suggesting an accelerated aging process. The production of an abnormal lamin A, a nuclear envelope protein, plays a causal role in both normal aging and accelerated aging diseases, known as laminopathies. Importantly, we identified the abnormal lamin A (prelamin A), accompanied by a down-regulation of a lamin A processing enzyme (Zmpste24) in the kidney of the GMF-TG mice. The GMF-TG mice showed accelerated aging in the kidney, compared with wild-type mice, showing increased TGF-β1, CTGF gene and serum creatinine. The gene expression of p21/waf1 was increased at an earlier stage of life, at 10 weeks, which was in turn down-regulated at a later stage, at 60 weeks. In conclusion, we propose that GMF-TG mice might be a novel mouse model of accelerated aging, due to the abnormal lamin A.

  18. Post-traumatic stress disorder among asylum seekers and refugees in Istanbul may be predicted by torture and loss due to violence.

    Science.gov (United States)

    Tufan, Ali Evren; Alkin, Melis; Bosgelmez, Sukriye

    2013-06-01

    Turkey is both a source and target for asylum seekers seeking refugee status in countries of European Union. There is a scarcity of research on the mental health issues of asylum seekers and refugees residing in Turkey. This study aimed: 1) to provide clinical and demographic information on asylum seekers and refugees receiving mental health services from a non-governmental refugee support program in Istanbul between 2005 and 2007, and 2) to evaluate the differences between patients diagnosed with post-traumatic stress disorder (PTSD) with those who did not meet criteria. The study was conducted at the Mental Health Division of the Refugee Advocacy Support Group. Between July 2005 and February 2007, 1209 asylum seekers applied to the support group; 75 of these individuals (6.2%) were referred for psychiatric evaluation while 57 were diagnosed as having a psychopathology. The number of analyzed subjects was 57. PTSD and major depressive disorder were the most common diagnoses (55.2% for both). The most common criteria of PTSD reported were problems in concentration and social isolation (97.3% for both). Suffering torture and losing a significant other due to violence were found to be associated with a diagnosis of PTSD. This study is the first of its kind to be conducted on a mixed refugee population residing in Turkey and focusing on their mental health problems. Our results should be tested within larger samples of refugees residing in different cities of Turkey.

  19. Days out of role due to common physical and mental conditions: results from the Northern Ireland study of health and stress.

    Science.gov (United States)

    Ennis, Edel; O'Neill, S; Murphy, S; Bunting, B

    2016-11-01

    Days out of role due to health problems are a major source of lost human capital. We examined the relative importance of common physical and mental disorders in accounting for days out of role in Northern Ireland using the Northern Ireland Study of Health and Stress (NISHS) WHO World Mental Health (WMH) Survey. Face-to-face interviews were carried out with 4340 respondents (68.4 % response rate). Multiple regression analysis estimated associations of specific chronic physical disorders and mental disorders conditions and comorbidities with days out of role controlling for basic socio-demographics. Overall, 16.8 % of respondents had at least one day totally out of role in the previous year. The strongest population-level effect was associated with arthritis, which accounted for 23.5 % of all days out of role. The strongest individual-level effects (days out of role per year) were associated with any anxiety disorder (32.3) arthritis (26.1) and pain (22.0). The 11 conditions accounted for 93 % of all days out of role, as measured by population attributable risk proportions (PARPs). Common health conditions, including mental disorders, make up a large proportion of the number of days out of role and should be addressed to substantially increase overall productivity.

  20. Work stress and burnout among physicians and nurses in Internal and Emergency Departments

    Directory of Open Access Journals (Sweden)

    Paola Gnerre

    2017-06-01

    Full Text Available Burnout has been defined as loss of enthusiasm for work, feelings of cynicism, and a low sense of personal accomplishment. Work environment and working conditions exposes the individual to numerous factors of stress. Stress-related diseases are defined as burnout. The increased workload, the repeated reorganizations in the hospital with iterative downsizing suggestions and budget cuts, without any perspective of career progression, with a social culture of bureaucracy and blame, resulting both in subtracting direct care time with patients and in the fear by healthcare professionals from the burden of their responsibility, are the backgrounds on which more and more frequent cases of burnout may develop. We need to establish homogenous standards all over the national territory on workload and about the procedures that have to be implemented for the prevention of burnout in our wards.

  1. Shakedown and stress range of torispherical heads under cyclic internal pressure

    International Nuclear Information System (INIS)

    Kalnins, A.; Updike, D.P.

    1996-01-01

    Two effects on shakedown of torispherical heads are addressed in this paper: (1) changing geometry, and (2) initial pressurization, such as by a hydro (or proof) test. Shakedown and the cycled stress intensity range are calculated for two head geometries, having diameter-to-thickness ratios of 238 and 192. The calculations are carried out following two approaches: (1) using a nonlinear, elastic-plastic algorithm that accounts for changes in geometry, and (2) using elastic stresses in the undeformed geometry, which is the commonly used approach. The results show that, when the two geometries are subjected to the same initial and cyclic pressures, shakedown is achieved by the first approach but not by the second. Since real heads do benefit from geometry changes, and since most design codes require hydro (or proof) tests before operation, the first approach is recommended for the design of torispherical heads

  2. The Mediating Roles of Rejection Sensitivity and Proximal Stress in the Association Between Discrimination and Internalizing Symptoms Among Sexual Minority Women.

    Science.gov (United States)

    Dyar, Christina; Feinstein, Brian A; Eaton, Nicholas R; London, Bonita

    2018-01-01

    The negative impact of discrimination on mental health among lesbian, gay, and bisexual populations has been well documented. However, the possible mediating roles of sexual orientation rejection sensitivity and rejection-based proximal stress in the association between discrimination and internalizing symptoms remain unclear. Rejection-based proximal stress is a subset of proximal stressors that are theorized to arise from concerns about and expectations of sexual orientation-based rejection and discrimination. Drawing on minority stress theory, we tested potential mediating effects using indirect effects structural equation modeling in a sample of 300 sexual minority women. Results indicated that the indirect effect of discrimination on internalizing symptoms (a latent variable indicated by depression and anxiety symptoms) through sexual orientation rejection sensitivity and rejection-based proximal stress (a latent variable indicated by preoccupation with stigma, concealment motivation, and difficulty developing a positive sexual identity) was significant. Additionally, the indirect effects of discrimination on rejection-based proximal stress through sexual orientation rejection sensitivity and of sexual orientation rejection sensitivity on internalizing symptoms through rejection-based proximal stress were also significant. These findings indicate that sexual orientation rejection sensitivity plays an important role in contributing to rejection-based proximal stress and internalizing symptoms among sexual minority women.

  3. The Migration, Mental Stress, and Tobacco use of Internal Migrants in China: The Moderating Effect of the Social Context of the Host Society.

    Science.gov (United States)

    Xie, Shenghua

    2017-11-10

    Previous studies on the relationship between mental stress and the tobacco use of internal migrants have not fully considered the social context of the host society. This study aims to examine how mental stress influences cigarette smoking in internal migrants in China by considering the social context of the host society. We used the RUMiC data that were collected in 15 cities distributed throughout 9 provinces of China. A total of 8,446 and 5,426 migrant workers were interviewed in 2008 and 2009, respectively. We selected individuals based on the criteria of age, salary, and hukou status. A total of 8,880 observations are valid for this study. This research used the logistic regression method to test the association between mental stress and the tobacco use of internal migrants. The results show that mental stress is not necessarily associated with the tobacco use of internal migrants. However, the effects of mental stress on tobacco use are moderated by the social context of the host society. This article calls for more attention to be paid to the moderate effect of social context in the host society on the association between mental stress and cigarette smoking of internal migrants. Moreover, this article underscores the importance of factors related to local societies in making and enacting tobacco control policies for migrants in developing countries.

  4. Reduction of residual stresses in internal skin of transient zones of PWR steam generator expanded tubes: tests with a ''rotating brush''

    International Nuclear Information System (INIS)

    Vidal, P.

    1984-04-01

    A process aiming at preventing or suppressing cracks under stress corrosion on the primary side in the expanded zones of PWR steam generator tubes has been studied; it consists in hammering the internal skin of tubes in these zones what reduces the level of residual expanding stresses to lower values around 100-150 MPa without modifying the stress level in external skin. Tests in magnesium chloride to estimate the residual stresses of tubes in low carbon stainless austenitic steel 18% Cr-12% Ni with molybdene [fr

  5. Pre-Adoption Adversity, Maternal Stress, and Behavior Problems at School-Age in International Adoptees

    Science.gov (United States)

    Gagnon-Oosterwaal, Noemi; Cossette, Louise; Smolla, Nicole; Pomerleau, Andree; Malcuit, Gerard; Chicoine, Jean-Francois; Belhumeur, Celine; Jeliu, Gloria; Begin, Jean; Seguin, Renee

    2012-01-01

    Internationally adopted children present more behavior problems than non-adopted children and are overrepresented in mental health services. These problems are related to children's pre-adoption environment, but adoptive families' functioning and characteristics may also affect the development of behavior problems in adopted children. The aim of…

  6. Internal stresses in steel plate generated by shape memory alloy inserts

    Czech Academy of Sciences Publication Activity Database

    Malard, B.; Pilch, Jan; Šittner, Petr; Davydov, V.; Sedlák, Petr; Konstantinidis, K.; Hughes, D. J.

    2012-01-01

    Roč. 60, č. 3 (2012), s. 1378-1394 ISSN 1359-6454 R&D Projects: GA ČR GAP108/10/1296 Grant - others:SMARTNETS(XE) FP7-NMP2-2011-262806 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z20760514 Keywords : shape memory alloy * NiTi * residual stress * neutron diffraction * strain scanning Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.941, year: 2012 http://www.sciencedirect.com/science/article/pii/S1359645411007294

  7. How do line managers experience and handle the return to work of employees on sick leave due to work-related stress? A one-year follow-up study.

    Science.gov (United States)

    Ladegaard, Yun; Skakon, Janne; Elrond, Andreas Friis; Netterstrøm, Bo

    2017-08-28

    To examine how line managers experience and manage the return to work process of employees on sick leave due to work-related stress and to identify supportive and inhibiting factors. Semi-structured interviews with 15 line managers who have had employees on sick leave due to work-related stress. The grounded theory approach was employed. Even though managers may accept the overall concept of work-related stress, they focus on personality and individual circumstances when an employee is sick-listed due to work-related stress. The lack of a common understanding of stress creates room for this focus. Line managers experience cross-pressure, discrepancies between strategic and human-relationship perspectives and a lack of organizational support in the return to work process. Organizations should aim to provide support for line managers. Research-based knowledge and guidelines on work-related stress and return to work process are essential, as is the involvement of coworkers. A commonly accepted definition of stress and a systematic risk assessment is also important. Cross-pressure on line managers should be minimized and room for adequate preventive actions should be provided as such an approach could support both the return to work process and the implementation of important interventions in the work environment. Implication for rehabilitation Organizations should aim to provide support for line managers handling the return to work process. Cross-pressure on line managers should be minimized and adequate preventive actions should be provided in relation to the return to work process. Research-based knowledge and guidelines on work-related stress and return to work are essential. A common and formal definition of stress should be emphasized in the workplace.

  8. Repeated short-term stress synergizes the ROS signalling through up regulation of NFkB and iNOS expression induced due to combined exposure of trichloroethylene and UVB rays.

    Science.gov (United States)

    Ali, Farrah; Sultana, Sarwat

    2012-01-01

    Restraint stress is known to catalyse the pathogenesis of the variety of chronic inflammatory disorders. The present study was designed to evaluate the effect of repeated short-term stress (RRS) on cellular transduction apart from oxidative burden and early tumour promotional biomarkers induced due to combined exposure of trichloroethylene (TCE) and Ultra-violet radiation (UVB). RRS leads to the increase in the expression of the stress responsive cellular transduction elements NFkB-p65 and activity of iNOS in the epidermal tissues of mice after toxicant exposure. RRS augments the steep depletion of the cellular antioxidant machinery which was evidenced by the marked depletion in GSH (Glutathione and GSH dependant enzymes), superoxide dismutase and catalase activity that were observed at significance level of P stressed animals and down regulation of DT-diaphorase activity (P short-term stress in the toxic response of TCE and UVB radiation.

  9. Stress.

    Science.gov (United States)

    Chambers, David W

    2008-01-01

    We all experience stress as a regular, and sometimes damaging and sometimes useful, part of our daily lives. In our normal ups and downs, we have our share of exhaustion, despondency, and outrage--matched with their corresponding positive moods. But burnout and workaholism are different. They are chronic, dysfunctional, self-reinforcing, life-shortening habits. Dentists, nurses, teachers, ministers, social workers, and entertainers are especially susceptible to burnout; not because they are hard-working professionals (they tend to be), but because they are caring perfectionists who share control for the success of what they do with others and perform under the scrutiny of their colleagues (they tend to). Workaholics are also trapped in self-sealing cycles, but the elements are ever-receding visions of control and using constant activity as a barrier against facing reality. This essay explores the symptoms, mechanisms, causes, and successful coping strategies for burnout and workaholism. It also takes a look at the general stress response on the physiological level and at some of the damage American society inflicts on itself.

  10. Suppression of Human T Cell Proliferation Mediated by the Cathepsin B Inhibitor, z-FA-FMK Is Due to Oxidative Stress.

    Directory of Open Access Journals (Sweden)

    Tanuja Rajah

    Full Text Available The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-fluoromethyl ketone (z-FA-FMK readily inhibits anti-CD3-induced human T cell proliferation, whereas the analogue benzyloxycarbonyl-phenylalanine-alanine-diazomethyl ketone (z-FA-DMK had no effect. In contrast, benzyloxycarbonyl-phenylalanine-alanine-chloromethyl ketone (z-FA-CMK was toxic. The inhibition of T cell proliferation mediated by z-FA-FMK requires not only the FMK moiety, but also the benzyloxycarbonyl group at the N-terminal, suggesting some degree of specificity in z-FA-FMK-induced inhibition of primary T cell proliferation. We showed that z-FA-FMK treatment leads to a decrease in intracellular glutathione (GSH with a concomitant increase in reactive oxygen species (ROS levels in activated T cells. The inhibition of anti-CD3-induced T cell proliferation mediated by z-FA-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC and L-cysteine, whereas D-cysteine which cannot be metabolised to GSH has no effect. The inhibition of anti-CD3-induced up-regulation of CD25 and CD69 expression mediated by z-FA-FMK was also attenuated in the presence of exogenous GSH. Similar to cell proliferation, GSH, NAC and L-cysteine but not D-cysteine, completely restored the processing of caspase-8 and caspase-3 to their respective subunits in z-FA-FMK-treated activated T cells. Our collective results demonstrated that the inhibition of T cell activation and proliferation mediated by z-FA-FMK is due to oxidative stress via the depletion of GSH.

  11. Decadal Variations of the Western Subarctic Gyre and Main Pycnocline Depth due to Wind Stress Change in the Northern North Pacific

    Science.gov (United States)

    Nagano, A.; Wakita, M.

    2017-12-01

    From the late 1990s to the early 2000s, the western subarctic gyre of the North Pacific, a cyclonic circulation in the western subarctic region, shrank northward associated with a decadal increase of sea surface height (SSH). This gyre change displaced the main pycnocline (halocline) downward and is expected to contribute to the deepening of the overlying temperature minimum layer. This is considered to affect the biogeochemical conditions in the western subarctic region, where is known as substantially slow ocean acidification region. In this study, on the basis of wind stress field data in the subpolar region (40˚N—54˚N, 160˚E—135˚W) during 1979—2014 provided by U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis, we estimated the variation in SSH, solving the vorticity gradient equation on the beta plane. Decadal increase in SSH at Station K2 (47˚N, 160˚E), representative point of the western subarctic region, was well produced by the calculation, and the correlation coefficient with altimetric SSH exceeds 0.6. The calculated SSH variation consists of the variations due to the barotropic and baroclinic Rossby wave modes. The gyre shrinkage is found to be caused primarily by the barotropic response to the wind change in the whole subpolar region and secondary by the first baroclinic response. Meanwhile, the decadal deepening of the main pycnocline at K2 is attributed to the baroclinic responses of the higher (second, third, and fourth) vertical modes to the local wind change.

  12. Market stresses and readjustment: politics and pragmatism in the international uranium market

    International Nuclear Information System (INIS)

    Neff, T.L.

    1983-01-01

    Historically, the United States uranium market was isolated from international markets; therefore, United States consumers had little incentive to look abroad. Later, the government imposed an embargo on imports of uranium for domestic use. The phase-out of the embargo and recent discovery of high-grade deposits in Australia and Western Canada, as well as large intermediate-cost deposits in Africa, assure that the United States market will be affected by international developments more than in the past. Projected uranium-consumer supply arrangements are compared with enrichment commitments to reactor requirements for several key countries. For all areas, both uranium supply and enrichment commitments exceed reactor needs until at least 1985. Inventory buildup will depend upon what adjustments are made. Uranium prices have never been set by market forces alone and governmental policies and political struggles may have a significant impact on price. 8 figures

  13. Estimation of the internal radiation dose received by the adult population of Graz due to the contamination with radioactive iodine and cesium

    International Nuclear Information System (INIS)

    Rabitsch, H.; Kahr, G.

    1991-07-01

    During the first months following the fallout we have measured the activities of J-131 in some human thyroids. To study the long-term variation of radiocesium with time, we have observed the activity level of Cs-134 and Cs-137 in human muscle tissues over a period of 4 years. Simultaneously we have determined the activities of the naturally occuring potassium-40 in all samples, which were taken at forensic autopsies of persons deceased in the area of Graz. Comparisons of iodine and radiocesium activities measured in the samples with data obtained by other studies after nuclear weapon tests are given. Average individual thyroid dose was calculated to be 556.1 μSv. The main part of this thyroid dose is caused by the inhalation pathway. Effective individual dose equivalents originated by the radiocesium body content were calculated by means of time-integrated activities and the method of absorbed fractions. Dose estimations based on data of the Standard Man and a distribution factor of 0.7 was assumed with regards to the amount of radiocesium and K-40 in muscle mass. From the measurements, we have estimated a mean individual effective dose equivalent of 252.2 μSv due to internal exposure to radiocesium during the 4 years following the fallout. Estimated dose values are compared with predictions and the exposure caused by K-40. (Authors, shortened by Quittner)

  14. Reversible Modulation of DNA-Based Hydrogel Shapes by Internal Stress Interactions.

    Science.gov (United States)

    Hu, Yuwei; Kahn, Jason S; Guo, Weiwei; Huang, Fujian; Fadeev, Michael; Harries, Daniel; Willner, Itamar

    2016-12-14

    We present the assembly of asymmetric two-layer hybrid DNA-based hydrogels revealing stimuli-triggered reversibly modulated shape transitions. Asymmetric, linear hydrogels that include layer-selective switchable stimuli-responsive elements that control the hydrogel stiffness are designed. Trigger-induced stress in one of the layers results in the bending of the linear hybrid structure, thereby minimizing the elastic free energy of the systems. The removal of the stress by a counter-trigger restores the original linear bilayer hydrogel. The stiffness of the DNA hydrogel layers is controlled by thermal, pH (i-motif), K + ion/crown ether (G-quadruplexes), chemical (pH-doped polyaniline), or biocatalytic (glucose oxidase/urease) triggers. A theoretical model relating the experimental bending radius of curvatures of the hydrogels with the Young's moduli and geometrical parameters of the hydrogels is provided. Promising applications of shape-regulated stimuli-responsive asymmetric hydrogels include their use as valves, actuators, sensors, and drug delivery devices.

  15. A PVDF-Based Sensor for Internal Stress Monitoring of a Concrete-Filled Steel Tubular (CFST) Column Subject to Impact Loads.

    Science.gov (United States)

    Du, Guofeng; Li, Zhao; Song, Gangbing

    2018-05-23

    Impact loads can have major adverse effects on the safety of civil engineering structures, such as concrete-filled steel tubular (CFST) columns. The study of mechanical behavior and stress analysis of CFST columns under impact loads is very important to ensure their safety against such loads. At present, the internal stress monitoring of the concrete cores CFST columns under impact loads is still a very challenging subject. In this paper, a PVDF (Polyvinylidene Fluoride) piezoelectric smart sensor was developed and successfully applied to the monitoring of the internal stress of the concrete core of a CFST column under impact loads. The smart sensor consists of a PVDF piezoelectric film sandwiched between two thin steel plates through epoxy. The protection not only prevents the PVDF film from impact damages but also ensures insulation and waterproofing. The smart sensors were embedded into the circular concrete-filled steel tube specimen during concrete pouring. The specimen was tested against impact loads, and testing data were collected. The time history of the stress obtained from the PVDF smart sensor revealed the evolution of core concrete internal stress under impact loads when compared with the impact force⁻time curve of the hammer. Nonlinear finite element simulations of the impact process were also carried out. The results of FEM simulations had good agreement with the test results. The results showed that the proposed PVDF piezoelectric smart sensors can effectively monitor the internal stress of concrete-filled steel tubular columns under impact loads.

  16. Differential determination of perceived stress in medical students and high-school graduates due to private and training-related stressors

    Science.gov (United States)

    Herrmann–Werner, Anne; Keifenheim, Katharina Eva; Loda, Teresa; Bugaj, Till Johannes; Nikendei, Christoph; Lammerding–Köppel, Maria; Zipfel, Stephan; Junne, Florian

    2018-01-01

    Objective Numerous studies from diverse contexts have confirmed high stress levels and stress-associated health impairment in medical students. This study aimed to explore the differential association of perceived stress with private and training-related stressors in medical students according to their stage of medical education. Methods Participants were high-school graduates who plan to study medicine and students in their first, third, sixth, or ninth semester of medical school or in practical medical training. The self-administered questionnaire included items addressing demographic information, the Perceived Stress Questionnaire, and items addressing potential private and training-related stressors. Results Results confirmed a substantial burden of perceived stress in students at different stages of their medical education. In particular, 10–28% of students in their third or ninth semesters of medical school showed the highest values for perceived stress. Training-related stressors were most strongly associated with perceived stress, although specific stressors that determined perceived stress varied across different stages of students’ medical education. High-school graduates highly interested in pursuing medical education showed specific stressors similar to those of medical students in their third, sixth, or ninth semesters of medical school, as well as stress structures with heights of general stress rates similar to those of medical students at the beginning of practical medical training. Conclusions High-school graduates offer new, interesting information about students’ fears and needs before they begin medical school. Medical students and high-school graduates need open, comprehensive information about possible stressors at the outset of and during medical education. Programmes geared toward improving resilience behaviour and teaching new, functional coping strategies are recommended. PMID:29385180

  17. Differential determination of perceived stress in medical students and high-school graduates due to private and training-related stressors.

    Science.gov (United States)

    Erschens, Rebecca; Herrmann-Werner, Anne; Keifenheim, Katharina Eva; Loda, Teresa; Bugaj, Till Johannes; Nikendei, Christoph; Lammerding-Köppel, Maria; Zipfel, Stephan; Junne, Florian

    2018-01-01

    Numerous studies from diverse contexts have confirmed high stress levels and stress-associated health impairment in medical students. This study aimed to explore the differential association of perceived stress with private and training-related stressors in medical students according to their stage of medical education. Participants were high-school graduates who plan to study medicine and students in their first, third, sixth, or ninth semester of medical school or in practical medical training. The self-administered questionnaire included items addressing demographic information, the Perceived Stress Questionnaire, and items addressing potential private and training-related stressors. Results confirmed a substantial burden of perceived stress in students at different stages of their medical education. In particular, 10-28% of students in their third or ninth semesters of medical school showed the highest values for perceived stress. Training-related stressors were most strongly associated with perceived stress, although specific stressors that determined perceived stress varied across different stages of students' medical education. High-school graduates highly interested in pursuing medical education showed specific stressors similar to those of medical students in their third, sixth, or ninth semesters of medical school, as well as stress structures with heights of general stress rates similar to those of medical students at the beginning of practical medical training. High-school graduates offer new, interesting information about students' fears and needs before they begin medical school. Medical students and high-school graduates need open, comprehensive information about possible stressors at the outset of and during medical education. Programmes geared toward improving resilience behaviour and teaching new, functional coping strategies are recommended.

  18. Role of internal stresses in the transient of irradiation growth of zircaloy-2

    International Nuclear Information System (INIS)

    Tome, C.N.; Christodoulou, N.; Turner, P.A.; Miller, M.A.; Woo, C.H.; Root, J.; Holden, T.M.

    1995-07-01

    A 'self-consistent' polycrystalline model is used to simulate irradiation growth of Zircaloy-2 samples irradiated at about 330 K. The predictions of the model are compared with experimental measurements obtained from specimens irradiated in the Advanced Test Reactor (ATR) at Idaho Falls. Three types of material are studied here: annealed, cold worked in tension and cold worked by rolling. In general, the growth rate attains a steady-state value after it goes through a transient that depends on the initial state of the material. The transient growth behaviour is explained in terms of the evolution of intergranular residual stresses that are present in the sample, and in terms of the dislocation structure. From this study, information regarding irradiation creep and growth mechanisms occurring at the single crystal level is obtained. (author). 28 refs., 1 tab., 4 figs

  19. Phase Identification and Internal Stress Analysis of Steamside Oxides on Plant Exposed Superheater Tubes

    DEFF Research Database (Denmark)

    Pantleon, Karen; Montgomery, Melanie

    2012-01-01

    During long-term, high-temperature exposure of superheater tubes in thermal power plants, various oxides are formed on the inner side (steamside) of the tubes, and oxide spallation is a serious problem for the power plant industry. Most often, oxidation in a steam atmosphere is investigated...... in laboratory experiments just mimicking the actual conditions in the power plant for simplified samples. On real plant-exposed superheater tubes, the steamside oxides are solely investigated microscopically. The feasibility of X-ray diffraction for the characterization of steamside oxidation on real plant......-exposed superheater tubes was proven in the current work; the challenges for depth-resolved phase analysis and phase-specific residual stress analysis at the inner side of the tubes with concave surface curvature are discussed. Essential differences between the steamside oxides formed on two different steels...

  20. Oxidative stress increases internal calcium stores and reduces a key mitochondrial enzyme.

    Science.gov (United States)

    Gibson, Gary E; Zhang, Hui; Xu, Hui; Park, Larry C H; Jeitner, Thomas M

    2002-03-16

    Fibroblasts from patients with genetic and non-genetic forms of Alzheimer's disease (AD) show many abnormalities including increased bombesin-releasable calcium stores (BRCS), diminished activities of the mitochondrial alpha-ketoglutarate dehydrogenase complex (KGDHC), and an altered ability to handle oxidative stress. The link between genetic mutations (and the unknown primary event in non-genetic forms) and these other cellular abnormalities is unknown. To determine whether oxidative stress could be a convergence point that produces the other AD-related changes, these experiments tested in fibroblasts the effects of H(2)O(2), in the presence or absence of select antioxidants, on BRCS and KGDHC. H(2)O(2) concentrations that elevated carboxy-dichlorofluorescein (c-H(2)DCF)-detectable ROS increased BRCS and decreased KGDHC activity. These changes are in the same direction as those in fibroblasts from AD patients. Acute treatments with the antioxidants Trolox, or DMSO decreased c-H(2)DCF-detectable ROS by about 90%, but exaggerated the H(2)O(2)-induced increases in BRCS by about 4-fold and did not alter the reduction in KGDHC. Chronic pretreatments with Trolox more than doubled the BRCS, tripled KGDHC activities, and reduced the effects of H(2)O(2). Pretreatment with DMSO or N-acetyl cysteine diminished the BRCS and either had no effect, or exaggerated the H(2)O(2)-induced changes in these variables. The results demonstrate that BRCS and KGDHC are more sensitive to H(2)O(2) derived species than c-H(2)DCF, and that oxidized derivatives of the antioxidants exaggerate the actions of H(2)O(2). The findings support the hypothesis that select abnormalities in oxidative processes are a critical part of a cascade that leads to the cellular abnormalities in cells from AD patients.

  1. Numerical and experimental evaluation of the residual stress relaxation and the influence zone due to application of the crack compliance method

    International Nuclear Information System (INIS)

    Sandoval-Pineda, J M; Garcia-Lira, J; Urriolagoitia-Sosa, G; Urriolagoitia-Calderon, G; Hernandez-Gomez, L H; Beltran-Fernandez, J A; RodrIguez-Martinez, R

    2009-01-01

    This paper presents the results concerning an evaluation of the crack compliance method. The research was focused on the relaxation caused by a cut induced to obtain the data required to calculate the residual stress field. The main objective in this research is to establish the optimum place to cut in a specimen that has suffered a failure and how extended is the zone of relaxed stresses. It has been recognized that a crack vanishes the beneficial or detrimental effects of the residual stress fields. This research has been performed in a numerical and experimental way, so results can be compared and FEM on this topic can be assessed.

  2. Numerical and experimental evaluation of the residual stress relaxation and the influence zone due to application of the crack compliance method

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval-Pineda, J M; Garcia-Lira, J [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de IngenierIa Mecanica y Electrica (ESIME), Unidad profesional, Azcapotzalco, Av. de las Granjas No. 682, Col. Sta. Catarina Azcapotzalco, C.P. 02550, Mexico D.F. Mexico (Mexico); Urriolagoitia-Sosa, G; Urriolagoitia-Calderon, G; Hernandez-Gomez, L H; Beltran-Fernandez, J A; RodrIguez-Martinez, R, E-mail: jsandovalp@ipn.m, E-mail: guiurri@hotmail.co [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion (SEPI), Escuela Superior de IngenierIa Mecanica y Electrica (ESIME). Edificio 5. 2do Piso, Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, C.P. 07738, Mexico, D.F. Mexico (Mexico)

    2009-08-01

    This paper presents the results concerning an evaluation of the crack compliance method. The research was focused on the relaxation caused by a cut induced to obtain the data required to calculate the residual stress field. The main objective in this research is to establish the optimum place to cut in a specimen that has suffered a failure and how extended is the zone of relaxed stresses. It has been recognized that a crack vanishes the beneficial or detrimental effects of the residual stress fields. This research has been performed in a numerical and experimental way, so results can be compared and FEM on this topic can be assessed.

  3. Transient thermal stresses in a transversely isotropic finite composite hollow circular cylinder due to arbitrary surface heat-generations and surrounding temperatures

    International Nuclear Information System (INIS)

    Sugano, Y.

    1981-01-01

    An exact solution is given for the temperature distribution, the thermal stresses and displacements in a transversely isotropic finite composite hollow circular cylinder composed of two distinct cylindrical laminae. The temperature field is determined by using of the Laplace transform and the finite Fourier-cosine transform, respectively, with respect to time and axial coordinate included in the governing equation and the associated thermal stresses and displacements are analvsed by the use of a set of stress functions closely related to the Love's function valid for the axisymmetric isothermal problem of isotropic bodies. (orig.)

  4. Differences in the cyclic deformation behaviour of quenched and tempered steel 42 CrMo 4 (AISI 4140) due to stress- and strain-control

    International Nuclear Information System (INIS)

    Schulze, V.; Lang, K.-H.; Voehringer, O.; Macherauch, E.

    1998-01-01

    Cyclic stress-strain-curves and Manson-Coffin-plots of quenched and tempered steel 42 CrMo 4 (AISI 4140) strongly depend on whether they are determined under stress- or total-strain-control. At total-strain-controlled experiments, this is caused on the one hand by comparatively high initial stress-amplitudes which lead to distinctive cyclic work softening. On the other hand, the occuring differences in the evolution of inhomogeneous deformation patterns at both types of loading, which can be recorded by means of photoelasticity and microscopy, lead to differently distributed plastic deformations and to different integral values of plastic strain. (orig.)

  5. Metallic materials for heat exchanger components and highly stressed internal of HTR reactors for nuclear process heat generation

    International Nuclear Information System (INIS)

    1982-01-01

    The programme was aimed at the development and improvement of materials for the high-temperature heat exchanger components of a process steam HTR. The materials must have high resistance to corrosion, i.e. carburisation and internal oxidation, and high long-term toughness over a wide range of temperatures. They must also meet the requirements set in the nuclear licensing procedure, i.e. resistance to cyclic stress and irradiation, non-destructive testing, etc. Initially, it was only intended to improve and qualify commercial alloys. Later on an alloy development programme was initiated in which new, non-commercial alloys were produced and modified for use in a nuclear process heat facility. Separate abstracts were prepared for 19 pays of this volume. (orig./IHOE) [de

  6. BWR internals life assurance

    International Nuclear Information System (INIS)

    Herrera, M.L.; Stancavage, P.P.

    1988-01-01

    Boiling water reactor (BWR) internal components play an important role in power plant life extension. Many important internals were not designed for easy removal and changes in material properties and local environmental effects due to high radiation makes stress corrosion cracking more likely and more difficult to correct. Over the past several years, operating experience has shown that inspection, monitoring and refurbishment can be accomplished for internal structures with existing technology. In addition, mitigation techniques which address the causes of degradation are available to assure that life extension targets can be met. This paper describes the many considerations and aspects when evaluating life extension for reactor vessel internals

  7. Role of internal marketing, organizational commitment, and job stress in discerning the turnover intention of Korean nurses.

    Science.gov (United States)

    Lee, Haejung; Kim, Myoung-Soo; Yoon, Jung-A

    2011-06-01

    The purpose of this study was to examine the discriminating factors of Korean nurses' turnover intention (TI) among internal marketing (IM), organizational commitment (OC), and job stress (JS). Nurses (n = 185) who had worked for 1-10 years were surveyed from six general hospitals in South Korea. The data were collected by using questionnaires and were analyzed with descriptive statistics and discriminant analysis. The participants were grouped into three groups, depending on the level of their TI: "low TI group" (n = 58), "moderate TI group" (n = 96), and "high TI group" (n = 31). One function significantly discriminated between the high TI and low TI groups. The function correctly classified 84.3% of the participants into the two groups and 75.3% were correctly classified in the cross-validation. Organizational commitment was the most important factor. Job stress and the IM components of staffing-promotion, reward, management philosophy, working environment, and segmentation were significant discriminant factors of TI. Based on the findings of this study, we could conclude that OC, JS, and IM play important roles in the TI of nurses. Implying a career development system as an OC management strategy, an innovative promotion policy to change conservative organizational climates and a balance of effort-reward can be considered as managerial interventions to reduce nurses' TI. © 2010 The Authors. Japan Journal of Nursing Science © 2010 Japan Academy of Nursing Science.

  8. Assessment of external and internal doses due to farming in high background radiation areas in old tin mining localities in Jos-plateau, Nigeria

    International Nuclear Information System (INIS)

    Jibiri, N.N.; Farai, I.P.; Alausa, S.K.

    2009-01-01

    Farming on soils situated in high background radiation areas can result to enhanced radiation exposure scenarios and pathways to humans. To assess the likely levels of exposures, farm soil samples were collected from different farmlands in three old tin mining localities (Bitsichi, Bukuru and Ropp) in Jos Plateau Nigeria, known for high radiations. The soil samples were analyzed for the activity concentrations of 226 Ra, 232 Th and 40 K, using gamma-ray spectroscopy. The outdoor annual effective dose rates were calculated using the activity concentrations of the radionuclides and were found to vary from 0.07 mSv to 2.02 mSv across the three localities. Considering dust generation from soil tillage and inadvertent ingestion of soil particles, the likely internal radiation hazards were estimated using conservative dust and soil loading factors. The total average annual effective dose rates due to 226 Ra and 232 Th that could result from dust inhalation and ingestion of soil particles were 16.9 μSv, 8.1 μSv and 8.8 μSv, respectively for Bitsichi, Bukuru and Ropp. Though these values are about 5% the outdoor exposures to the farmers in those farms and greater than 1 μSv y-1, from the point of view of radiation protection and risk, they are significant. It suffices to say, therefore, that the results of this study will create the possibility of the importance to evaluate the health risk among the farming population and workplace environments which often is not covered by regulations concerning health protection. (author)

  9. Risk markers of all-cause and diagnosis-specific disability pension--a prospective cohort study of individuals sickness absent due to stress-related mental disorders

    DEFF Research Database (Denmark)

    Ishtiak-Ahmed, Kazi; Perski, Aleksander; Mittendorfer-Rutz, Ellenor

    2014-01-01

    BACKGROUND: Stress-related mental disorders rank among the leading causes of sickness absence in several European countries. The aim of this study was to investigate predictors of all-cause and diagnosis-specific disability pension in sickness absentees with stress-related mental disorders. METHO....... The variation in the effect of risk markers with regard to age and diagnosis of disability pension speaks in favour of the importance of a person-centered approach in treatment and rehabilitation....

  10. The effects of progressive muscular relaxation as a nursing procedure used for those who suffer from stress due to multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Paolla Gabrielle Nascimento Novais

    Full Text Available ABSTRACT Objective: to evaluate the effect of progressive muscle relaxation as a nursing procedure on the levels of stress for sufferers of multiple sclerosis. Method: random clinical trials conducted at the Neurology outpatients unit at a University Hospital. The sample consisted of 40 patients who were being monitored as outpatients (20 in a control group and 20 in an experimental group. The Progressive Muscle Relaxation technique was used. The control variables were collected through interviews that were recorded on forms and on the Perceived Stress Scale that we used. Five meetings were held every fortnight covering a period of eight weeks. The experimental group was advised to carry out daily progressive muscle relaxation activities. After eight weeks of these activities, they were evaluated again to measure their levels of stress. In order to analyze the data used, the software package Statistics for Social Sciences version 19.0 was used. Results: the application of the t test showed a significant reduction in the Perceived Stress Scale scores in the experimental group (p<0.001, which in turn proved that there was a reduction in the levels of stress after the application of the relaxation practic-es. Conclusion: the progressive muscle relaxation activities contributed to the reduction in stress levels for multiple sclerosis suffers and thus can be used in nursing for patients. Clinical Trials Identifier: NCT 02673827.

  11. The responsiveness of the International Prostate Symptom Score, Incontinence Impact Questionnaire-7 and Depression, Anxiety and Stress Scale-21 in patients with lower urinary tract symptoms.

    Science.gov (United States)

    Choi, Edmond P H; Chin, Weng Yee; Lam, Cindy L K; Wan, Eric Y F

    2015-08-01

    To examine the responsiveness of a combined symptom severity and health-related quality of life measure, condition-specific health-related quality of life measure and mental health measure in patients with lower urinary tract symptoms. To establish the responsiveness of measures that accurately capture the change in health status of patients is crucial before any longitudinal studies can be appropriately planned and evaluated. Prospective longitudinal observational study. 402 patients were surveyed at baseline and 1-year using the International Prostate Symptom Score, the Incontinence Impact Questionnaire-7 and Depression, Anxiety and Stress Scales-21. The internal and external responsiveness were assessed. Surveys were conducted from March 2013-July 2014. In participants with improvements, the internal responsiveness for detecting positive changes was satisfactory in males and females for all scales, expect for the Depression subscale. The health-related quality of life question of the International Prostate Symptom Score was more externally responsive than the Incontinence Impact Questionnaire-7. The International Prostate Symptom Score and Anxiety and Stress subscales were more responsive in males than in females. The symptom questions of the International Prostate Symptom Score and Anxiety and Stress subscales were not externally responsive in females. The health-related quality of life question of the International Prostate Symptom Score outperformed the Incontinence Impact Questionnaire-7 in both males and females, in terms of external responsiveness. © 2015 John Wiley & Sons Ltd.

  12. Three-dimensional shape transformations of hydrogel sheets induced by small-scale modulation of internal stresses

    Science.gov (United States)

    Wu, Zi Liang; Moshe, Michael; Greener, Jesse; Therien-Aubin, Heloise; Nie, Zhihong; Sharon, Eran; Kumacheva, Eugenia

    2013-03-01

    Although Nature has always been a common source of inspiration in the development of artificial materials, only recently has the ability of man-made materials to produce complex three-dimensional (3D) structures from two-dimensional sheets been explored. Here we present a new approach to the self-shaping of soft matter that mimics fibrous plant tissues by exploiting small-scale variations in the internal stresses to form three-dimensional morphologies. We design single-layer hydrogel sheets with chemically distinct, fibre-like regions that exhibit differential shrinkage and elastic moduli under the application of external stimulus. Using a planar-to-helical three-dimensional shape transformation as an example, we explore the relation between the internal architecture of the sheets and their transition to cylindrical and conical helices with specific structural characteristics. The ability to engineer multiple three-dimensional shape transformations determined by small-scale patterns in a hydrogel sheet represents a promising step in the development of programmable soft matter.

  13. Interaction of TiO2 nanoparticles with the marine microalga Nitzschia closterium: Growth inhibition, oxidative stress and internalization

    International Nuclear Information System (INIS)

    Xia, Bin; Chen, Bijuan; Sun, Xuemei; Qu, Keming; Ma, Feifei; Du, Meirong

    2015-01-01

    The toxicity of TiO 2 engineered nanoparticles (NPs) to the marine microalga Nitzschia closterium was investigated by examining growth inhibition, oxidative stress and uptake. The results indicated that the toxicity of TiO 2 particles to algal cells significantly increased with decreasing nominal particle size, which was evidenced by the 96 EC 50 values of 88.78, 118.80 and 179.05 mg/L for 21 nm, 60 nm and 400 nm TiO 2 particles, respectively. The growth rate was significantly inhibited when the alga was exposed to 5 mg/L TiO 2 NPs (21 nm). Measurements of antioxidant enzyme activities showed that superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities were first induced and subsequently inhibited following exposure to 5 mg/L TiO 2 NPs. The depletion of antioxidant enzymes with a concomitant increase in malondialdehyde (MDA) levels and reactive oxygen species (ROS) posed a hazard to membrane integrity. A combination of flow cytometry analysis, transmission electron microscopy and Ti content measurement indicated that TiO 2 NPs were internalized in N. closterium cells. The level of extracellular ROS, which was induced by TiO 2 NPs under visible light, was negligible when compared with the intracellular ROS level (accounting for less than 6.0% of the total ROS level). These findings suggest that elevated TiO 2 nanotoxicity in marine environments is related to increased ROS levels caused by internalization of TiO 2 NPs. - Highlights: • Inhibition of marine microalgae by TiO 2 NPs and bulk particles was evaluated. • Aggregation of TiO 2 NPs and bulk particles was observed in marine algal test medium. • TiO 2 NPs induced damage to algal cell membranes as detected by flow cytometry. • Increased TiO 2 nanotoxicity to algal cells was caused by internalization of NPs

  14. Relationship between screw sagittal angle and stress on endplate of adjacent segments after anterior cervical corpectomy and fusion with internal fixation: a Chinese finite element study.

    Science.gov (United States)

    Zhang, Yu; Tang, Yibo; Shen, Hongxing

    2017-12-01

    In order to reduce the incidence of adjacent segment disease (ASD), the current study was designed to establish Chinese finite element models of normal 3rd~7th cervical vertebrae (C3-C7) and anterior cervical corpectomy and fusion (ACCF) with internal fixation , and analyze the influence of screw sagittal angle (SSA) on stress on endplate of adjacent cervical segments. Mimics 8.1 and Abaqus/CAE 6.10 softwares were adopted to establish finite element models. For C4 superior endplate and C6 inferior endplate, their anterior areas had the maximum stress in anteflexion position, and their posterior areas had the maximum stress in posterior extension position. As SSA increased, the stress reduced. With an increase of 10° in SSA, the stress on anterior areas of C4 superior endplate and C6 inferior endplate reduced by 12.67% and 7.99% in anteflexion position, respectively. With an increase of 10° in SSA, the stress on posterior areas of C4 superior endplate and C6 inferior endplate reduced by 9.68% and 10.22% in posterior extension position, respectively. The current study established Chinese finite element models of normal C3-C7 and ACCF with internal fixation , and demonstrated that as SSA increased, the stress on endplate of adjacent cervical segments decreased. In clinical surgery, increased SSA is able to play important role in protecting the adjacent cervical segments and reducing the incidence of ASD.

  15. Improvement in accuracy of the measurements of residual stresses due to circumferential welds in thin-walled pipe using Rayleigh wave method

    International Nuclear Information System (INIS)

    Akhshik, Siamak; Moharrami, Rasool

    2009-01-01

    To achieve an acceptable safety in many industrial applications such as nuclear power plants and power generation, it is extremely important to gain an understanding of the magnitudes and distributions of the residual stresses in a pipe formed by joining two sections with a girth butt weld. Most of the methods for high-accuracy measurement of residual stress are destructive. These destructive measurement methods cannot be applied to engineering systems and structures during actual operation. In this paper, we present a method based on the measurement of ultrasonic Rayleigh wave velocity variations versus the stress state for nondestructive evaluation of residual stress in dissimilar pipe welded joint. We show some residual stress profile obtained by this method. These are then compared with other profiles determined using a semi-destructive technique (hole-drilling) that makes it possible to check our results. According to the results, we also present a new method for adjusting the ultrasonic measurements to improve the agreement with the results obtained from other techniques.

  16. Revisiting the Humanisation of International Law: Limits and Potential : Obligations Erga Omnes, Hierarchy of Rules and the Principle of Due Diligence as the Basis for Further Humanisation

    NARCIS (Netherlands)

    V.P. Tzevelekos (Vassilis)

    2013-01-01

    textabstractThe article critically evaluates the theory of the humanisation of international law. First, it argues that despite human rights having impact on (other areas of) international law, this trend has in the past been somewhat inflated. A number of examples are given where human rights have

  17. International

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    This rubric reports on 10 short notes about international economical facts about nuclear power: Electricite de France (EdF) and its assistance and management contracts with Eastern Europe countries (Poland, Hungary, Bulgaria); Transnuclear Inc. company (a 100% Cogema daughter company) acquired the US Vectra Technologies company; the construction of the Khumo nuclear power plant in Northern Korea plays in favour of the reconciliation between Northern and Southern Korea; the delivery of two VVER 1000 Russian reactors to China; the enforcement of the cooperation agreement between Euratom and Argentina; Japan requested for the financing of a Russian fast breeder reactor; Russia has planned to sell a floating barge-type nuclear power plant to Indonesia; the control of the Swedish reactor vessels of Sydkraft AB company committed to Tractebel (Belgium); the renewal of the nuclear cooperation agreement between Swiss and USA; the call for bids from the Turkish TEAS electric power company for the building of the Akkuyu nuclear power plant answered by three candidates: Atomic Energy of Canada Limited (AECL), Westinghouse (US) and the French-German NPI company. (J.S.)

  18. Sublethal effects of a metal contamination due to uranium mine tailings in the three-spined stickleback (Gasterosteus aculeatus L.). Implication in the susceptibility to a biological stress

    International Nuclear Information System (INIS)

    Le Guernic, Antoine

    2015-01-01

    Uranium extraction has resulted in a remobilization of this actinide into mine surrounding ecosystems. Uses of metal salts during mining site rehabilitation, and the natural presence of metals have increased the metal contamination in hydro systems submitted to mine tailings. In situ experiments were conducted in two former French uranium mining sites. Three-spined stickleback caging was used to determine the sublethal effects of this metal mixture on this freshwater fish, as well as its effects on fish susceptibility to a sudden biological stress. This pollution, characterised by higher metal concentrations (especially for uranium), has led to an oxidative stress in sticklebacks visible through several bio-markers, and other effects dependent on the study site. The polymetallic contamination has modified the stickleback responses to the biological stress, by preventing their phagocytic and antioxidant responses. This work has reinforced the interest of the caging technique during environmental studies and that of immuno-markers in a multi-bio-marker approach. (author)

  19. Calorimetric features of release of plastic deformation induced internal stresses, and approach to equilibrium state on annealing of crystals and glasses

    Energy Technology Data Exchange (ETDEWEB)

    Johari, G.P., E-mail: joharig@mcmaster.ca

    2014-04-01

    Highlights: • Stress release in a glass occurs at a faster rate than structural relaxation. • Plastically-deformed glass would show two exothermic minima, and no glass transition. • Enthalpy matching procedure would yield an inaccurate fictive temperature. • Complex heat capacity may distinguish plastically-deformed from quench-formed glass. - Abstract: Plastic deformation of crystals and glasses produces internal strains (stresses), which change their energy and other thermodynamic properties. On annealing, these stresses decrease at a rate faster than the structure relaxes toward the equilibrium state. Mechanism of such relaxations in crystals differs from that in glasses and it also differs for glasses of different types. In all cases, the energy related properties decrease with time isothermally and on heating, resembling the structure relaxation of a stress-free glass. We consider these features and argue that kinetics of enthalpy loss with time yields the rate constants of the stress release and of the structure change, and not the viscosity determining α-relaxation time. Since thermal cycling does not recover the enthalpy from internal stresses, a glass with stresses has neither a glass-softening temperature, T{sub g}, nor a fictive temperature, T{sub f}. Plastic deformation would not rejuvenate a physically aged glass to the properties of its un-aged state. The Prigogine–Defay ratio can be extended to all T{sub f}s, and used to investigate the effect of distribution of relaxation times on its value, but it can not be defined for an internally stressed glass. After discussing the effects of annealing on the heat capacity and DSC scans, we conclude that on slow heating, glass with deformation-induced stresses would show two exothermic minima, and normal glass would show only one such minimum. Temperature-modulated scanning calorimetry would also distinguish an internally stressed glass from an equally high-enthalpy, stress-free glass. Enthalpy

  20. Work-Home Interference, Perceived Total Workload, and the Risk of Future Sickness Absence Due to Stress-Related Mental Diagnoses Among Women and Men: a Prospective Twin Study.

    Science.gov (United States)

    Svedberg, Pia; Mather, Lisa; Bergström, Gunnar; Lindfors, Petra; Blom, Victoria

    2018-02-01

    Work-home interference has been proposed as an important explanation for sickness absence (SA). Previous studies show mixed results, have not accounted for familial factors (genetics and shared everyday environment), or investigated diagnosis specific SA. The aim was to study whether work-home interference and perceived total workload predict SA due to stress-related mental diagnoses, or SA due to other mental diagnoses, among women and men, when adjusting for various confounders and familial factors. This study included 11,916 twins, 19-47 years (49% women). Data on work-to-home and home-to-work conflicts, perceived total workload, and relevant confounders were derived from a 2005 survey, and national register data on SA spells until 2013 were obtained. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Discordant twin pair design was applied to adjust for familial factors. Each one unit increase in work-to-home and home-to-work conflicts, and perceived total workload was associated with higher odds for SA due to stress-related mental diagnoses and to SA due to other mental diagnoses among women, when adjusting for sociodemographic factors (ORs 1.15-1.31). Including health or familial factors, no associations remained. For men, each one unit increase in work-to-home conflicts was associated with higher odds for SA due to stress-related diagnoses (ORs 1.23-1.35), independently of confounders. Work-to-home conflict was independently associated with future SA due to stress-related diagnoses among men only. Health- and work-related factors seem to be important confounders when researching work-home interference, perceived total workload, and SA. Not including such confounders involves risking drawing incorrect conclusions. Further studies are needed to confirm sex differences and whether genetic factors are important for the associations studied.