WorldWideScience

Sample records for stress bearing units

  1. Accuracy of Spindle Units with Hydrostatic Bearings

    Directory of Open Access Journals (Sweden)

    Fedorynenko Dmytro

    2016-06-01

    Full Text Available The work is devoted to the research of precision regularities in a spindle unit by the trajectory of the spindle installed on hydrostatic bearings. The mathematical model of trajectories spindle with lumped parameters that allows to define the position of the spindle with regard the simultaneous influence of design parameters, geometrical deviations ofform, temperature deformation bearing surfaces, the random nature of operational parameters and technical loads of hydrostatic bearings has been developed. Based on the results of numerical modeling the influence of shape errors of bearing surface of hydrostatic bearing on the statistical characteristics of the radius vector trajectories of the spindle by varying the values rotational speed of the spindle and oil pressure in front hydrostatic bearing has been developed. The obtained statistical regularities of precision spindle unit have been confirmed experimentally. It has been shown that an effective way to increase the precision of spindle units is to regulate the size of the gap in hydrostatic spindle bearings. The new design of an adjustable hydrostatic bearing, which can improve the accuracy of regulation size gap has been proposed.

  2. Stress-Softening Formulae of Polymer Bearings

    Directory of Open Access Journals (Sweden)

    M. H. B. M. Shariff

    2015-01-01

    Full Text Available The motivation for this work was the absence of closed form solutions that can reasonably describe the axial deformation behaviour of stress-softening polymer bearings. In this paper, new closed form solutions that exhibit Mullins phenomenon are developed. We show that the apparent Young modulus depends on the shape factor and the minimal infinitesimal strain. We furthermore found that, in a nonlinear deformation, the shape factor plays an important role in stress softening. The solutions are design friendly and are consistent with expected results.

  3. Contact Stress Design Parameters for Titanium Bearings, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Air-Lock's Phase I effort tested the effects of ball induced contact stresses on Titanium bearing races. The contact stress design limit that would achieve a...

  4. 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.

  5. 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.

  6. Reducing Stress-Corrosion Cracking in Bearing Alloys

    Science.gov (United States)

    Paton, N. E.; Dennies, D. P.; Lumsden, I., J.b.

    1986-01-01

    Resistance to stress-corrosion cracking in some stainless-steel alloys increased by addition of small amounts of noble metals. 0.75 to 1.00 percent by weight of palladium or platinum added to alloy melt sufficient to improve properties of certain stainless steels so they could be used in manufacture of high-speed bearings.

  7. Tilting-Pad Guide Bearing in Large Hydro-unit

    Directory of Open Access Journals (Sweden)

    Li-Feng Ma

    2000-01-01

    Full Text Available A new numerical method is proposed for predicting the nonlinearity of tilting-pad guide bearing oilfilm force in the rotor-bearing system in a large hydro-unit. Nonlinear displacement and velocity of the journal center, as well as nonlinear tilting angles and angular velocities of the pads in non-stationary Reynolds equation are taken into account. This method is also suited for other small rotor-bearing system. As an example, the response due to a momentarily created unbalance is Calculated. The nonlinear motion patterns of the pad and journal whirling orbit are obtained. Finally, the nonlinear orbit is compared to the linear one that could be calculated from linear stiffness and damping coefficients. It is shown that there are important differences between those two orbits and that the nonlinear simulation is more accurate.

  8. Uranium- and thorium-bearing pegmatites of the United States

    International Nuclear Information System (INIS)

    Adams, J.W.; Arengi, J.T.; Parrish, I.S.

    1980-04-01

    This report is part of the National Uranium Resource Evaluation (NURE) Program designed to identify criteria favorable for the occurrence of the world's significant uranium deposits. This project deals specifically with uranium- and thorium-bearing pegmatites in the United States and, in particular, their distribution and origin. From an extensive literature survey and field examination of 44 pegmatite localities in the United States and Canada, the authors have compiled an index to about 300 uranium- and thorium-bearing pegmatites in the United States, maps giving location of these deposits, and an annotated bibliography to some of the most pertinent literature on the geology of pegmatites. Pegmatites form from late-state magma differentiates rich in volatile constituents with an attendant aqueous vapor phase. It is the presence of an aqueous phase which results in the development of the variable grain size which characterizes pegmatites. All pegmatites occur in areas of tectonic mobility involving crustal material usually along plate margins. Those pegmatites containing radioactive mineral species show, essentially, a similar distribution to those without radioactive minerals. Criteria such as tectonic setting, magma composition, host rock, and elemental indicators among others, all serve to help delineate areas more favorable for uranium- and thorium-bearing pegmatites. The most useful guide remains the radioactivity exhibited by uranium- and thorium-bearing pegmatites. Although pegmatites are frequently noted as favorable hosts for radioactive minerals, the general paucity and sporadic distribution of these minerals and inherent mining and milling difficulties negate the resource potential of pegmatites for uranium and thorium

  9. Uranium- and thorium-bearing pegmatites of the United States

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.W.; Arengi, J.T.; Parrish, I.S.

    1980-04-01

    This report is part of the National Uranium Resource Evaluation (NURE) Program designed to identify criteria favorable for the occurrence of the world's significant uranium deposits. This project deals specifically with uranium- and thorium-bearing pegmatites in the United States and, in particular, their distribution and origin. From an extensive literature survey and field examination of 44 pegmatite localities in the United States and Canada, the authors have compiled an index to about 300 uranium- and thorium-bearing pegmatites in the United States, maps giving location of these deposits, and an annotated bibliography to some of the most pertinent literature on the geology of pegmatites. Pegmatites form from late-state magma differentiates rich in volatile constituents with an attendant aqueous vapor phase. It is the presence of an aqueous phase which results in the development of the variable grain size which characterizes pegmatites. All pegmatites occur in areas of tectonic mobility involving crustal material usually along plate margins. Those pegmatites containing radioactive mineral species show, essentially, a similar distribution to those without radioactive minerals. Criteria such as tectonic setting, magma composition, host rock, and elemental indicators among others, all serve to help delineate areas more favorable for uranium- and thorium-bearing pegmatites. The most useful guide remains the radioactivity exhibited by uranium- and thorium-bearing pegmatites. Although pegmatites are frequently noted as favorable hosts for radioactive minerals, the general paucity and sporadic distribution of these minerals and inherent mining and milling difficulties negate the resource potential of pegmatites for uranium and thorium.

  10. Relation Between Residual and Hoop Stresses and Rolling Bearing Fatigue Life

    Science.gov (United States)

    Oswald, Fred B.; Zaretsky, Erwin V.; Poplawski, Joseph V.

    2015-01-01

    Rolling-element bearings operated at high speed or high vibration may require a tight interference fit between the bore of the bearing and shaft to prevent rotation of the bearing bore around the shaft and fretting damage at the interfaces. Previous work showed that the hoop stresses resulting from tight interference fits can reduce bearing lives by as much as 65 percent. Where tight interference fits are required, case-carburized steel such as AISI 9310 or M50 NiL is often used because the compressive residual stresses inhibit subsurface crack formation and the ductile core inhibits inner-ring fracture. The presence of compressive residual stress and its combination with hoop stress also modifies the Hertz stress-life relation. This paper analyzes the beneficial effect of residual stresses on rolling-element bearing fatigue life in the presence of high hoop stresses for three bearing steels. These additional stresses were superimposed on Hertzian principal stresses to calculate the inner-race maximum shearing stress and the resulting fatigue life of the bearing. The load-life exponent p and Hertz stress-life exponent n increase in the presence of compressive residual stress, which yields increased life, particularly at lower stress levels. The Zaretsky life equation is described and is shown to predict longer bearing lives and greater load- and stress-life exponents, which better predicts observed life of bearings made from vacuum-processed steel.

  11. Properties of New Glass Ionomer Restorative Materials Marketed for Stress Bearing Areas

    Science.gov (United States)

    2018-03-22

    REPORT TYPE 22/03/2018 Poster 4. TITLE AND SUBTITLE Prope1iies of New Glass-Ionomer Restorative Materials Marketed for Stress -Bearing Areas 6...Adobe Professional 7 .0 INTRODUCTION Equia Forte is a new GIC which is marketed for posterior stress bearing restorations due to its newer...research on this and other newer glass ionomer systems being indicated for use in class II posterior stress - bearing preparations. OBJECTIVE The

  12. Synthesis and characterization of porous microspheres bearing pyrrolidone units

    Energy Technology Data Exchange (ETDEWEB)

    Maciejewska, M., E-mail: mmacieje@umcs.pl; Kołodyńska, D.

    2015-01-15

    Porous microspheres of glycydyl methacrylate (GMA) cross-linked with trimethylolpropane trimethacrylate (TRIM) were prepared with toluene as porogen by suspension-emulsion polymerization. With increasing molar ratio of the functional monomer to cross-linker, the epoxy group content increases significantly whereas the parameters of porous structure (specific surface area and total pore volume) decreases. In order to obtain adsorbents bearing functional groups the porous methacrylate network was modified by subsequent reaction with pyrrolidone. The materials were studied using elemental analysis, infrared spectroscopy, atomic force microscopy (AFM), attenuated total reflection (ATR) spectroscopy, Raman spectroscopy, thermal gravimetry. Additionally, polymers sorption capacity towards Cu(II) was investigated. - Highlights: • Porous microspheres with reactive epoxy group were synthesized. • Highly developed porous structure was created. • Pyrrolidone units were incorporated during ring–opening reaction. • Polymers sorption capacity towards Cu (II) was investigated.

  13. Relation Between Hertz Stress-Life Exponent, Ball-Race Conformity, and Ball Bearing Life

    Science.gov (United States)

    Zaretsky, Erwin V.; Poplawski, Joseph V.; Root, Lawrence E.

    2008-01-01

    ANSI/ABMA and ISO standards based on Lundberg-Palmgren bearing life theory are normalized for ball bearings having inner- and outerrace conformities of 52 percent (0.52) and made from pre-1940 bearing steel. The Lundberg-Palmgren theory incorporates an inverse 9th power relation between Hertz stress and fatigue life for ball bearings. The effect of race conformity on ball set life independent of race life is not incorporated into the Lundberg-Palmgren theory. In addition, post-1960 vacuum-processed bearing steel exhibits a 12th power relation between Hertz stress and life. The work reported extends the previous work of Zaretsky, Poplawski, and Root to calculate changes in bearing life--that includes the life of the ball set--caused by race conformity, Hertz stress-life exponent, ball bearing type and bearing series. The bearing fatigue life in actual application will usually be equal to or greater than that calculated using the ANSI/ABMA and ISO standards that incorporate the Lundberg-Palmgren theory. The relative fatigue life of an individual race is more sensitive to changes in race conformity for Hertz stress-life exponent n of 12 than where n = 9. However, when the effects are combined to predict actual bearing life for a specified set of conditions and bearing geometry, the predicted life of the bearing will be greater for a value of n = 12 than n = 9.

  14. Effect of Magnetohydrodynamic Couple Stresses on Dynamic Characteristics of Exponential Slider Bearing

    Directory of Open Access Journals (Sweden)

    N.B. Naduvinamani

    2017-05-01

    Full Text Available The effect of couple stresses on static and dynamic characteristics of exponential slider bearing in the presence of magnetic field considering squeeze action is theoretically analyzed in this paper. The modified magnetohydrodynamic couple stress Reynolds type equation is derived on the basis of Stokes couple stress model and closed form expressions are obtained for static and dynamic character coefficients. Comparing with bearing lubricated with non-conducting Newtonian lubricants, the magnetohydrodynamic couple stress lubrication provides the higher steady load carrying capacity, dynamic stiffness and damping coefficient. The exponential bearing shows higher efficiency for small film thickness at higher value of couple stress parameter and Hartmann number.

  15. 31 CFR 601.4 - Use of paper; interest-bearing securities of the United States.

    Science.gov (United States)

    2010-07-01

    ... PAPER FOR UNITED STATES CURRENCY AND OTHER SECURITIES § 601.4 Use of paper; interest-bearing securities of the United States. The existing distinctive papers shall be used for the printing of interest...

  16. The technology of the bearings used in the nuclear power generation system turbine generator units

    International Nuclear Information System (INIS)

    Vialettes, J.M.; Rossato, M.

    1997-01-01

    A bearing consists of all the stationary part which allow the relative motion in rotation or in translation, of a shaft line. Inside the bearing there is a journal bearing with a metallic anti-friction coating (the babbitt metal). The high power turbine generator unit rotors are supported by smooth transversal journal bearings fed with oil which fills the empty space and runs along the shaft. The technologies used for the bearings and the thrust bearings of the turbine generator units and the various shaft lines of the French CP0/CP1- and CP2/1300 MW-type nuclear power plants are described. The experience feedback is then discussed in terms of the dynamics of the shaft line, i.e. vibrational problems, the influence of the alignment and the babbitt metal incidents. (author)

  17. Evaluation of datum unit for diagnostics of journal-bearing systems

    International Nuclear Information System (INIS)

    Jeon, Byung Chul; Jung, Joon Ha; Youn, Byeng Doog; Kim, Yeon Whan; Bae, Yong Chae

    2015-01-01

    Journal bearings support rotors using fluid film between the rotor and the stator. Generally, journal bearings are used in large rotor systems such as turbines in a power plant, because even in high-speed and load conditions, journal bearing systems run in a stable condition. To enhance the reliability of journal-bearing systems, in this paper, we study health-diagnosis algorithms that are based on the supervised learning method. Specifically, this paper focused on defining the unit of features, while other previous papers have focused on defining various features of vibration signals. We evaluate the features of various lengths or units on the separable ability basis. From our results, we find that one cycle datum in the time-domain and 60 cycle datum in the frequency domain are the optimal datum units for real-time journal-bearing diagnosis systems

  18. Evaluation of datum unit for diagnostics of journal-bearing systems

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Byung Chul; Jung, Joon Ha; Youn, Byeng Doog [Dept. of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea, Republic of); Kim, Yeon Whan; Bae, Yong Chae [Power Generation Laboratory, KEPCO Research Institute, Daejeon (Korea, Republic of)

    2015-08-15

    Journal bearings support rotors using fluid film between the rotor and the stator. Generally, journal bearings are used in large rotor systems such as turbines in a power plant, because even in high-speed and load conditions, journal bearing systems run in a stable condition. To enhance the reliability of journal-bearing systems, in this paper, we study health-diagnosis algorithms that are based on the supervised learning method. Specifically, this paper focused on defining the unit of features, while other previous papers have focused on defining various features of vibration signals. We evaluate the features of various lengths or units on the separable ability basis. From our results, we find that one cycle datum in the time-domain and 60 cycle datum in the frequency domain are the optimal datum units for real-time journal-bearing diagnosis systems.

  19. Numerical Analysis of the Influence of Clearance on Stress State and Contact Pressure in Plain Bearings

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2017-12-01

    Full Text Available In the analysis of plain bearings by finite element method it is important to model as closely to real state the aspects that influence the stress and contact pressure: the loading mode, the properties of the materials, the lubrication system, the clearance between the shaft and the bearing body, the evolution in time of clearance correlated with the wear, etc. In order to study the effect of the clearance on the stress state, a plain bearing with nominal diameter d=40 mm was modeled. The contact pressure and the equivalent stress were computed for six discrete values of clearance, range from c=0 to c=0.3 mm. It has been shown that the increase of clearance generates an increase of the equivalent stress and contact pressure. The growth rate is higher for contact pressure, due to the decrease of the contact surface between the shaft and the bearing body

  20. Analysis of Nanoparticle Additive Couple Stress Fluids in Three-layered Journal Bearing

    International Nuclear Information System (INIS)

    Rao, T V V L N; Sufian, S; Mohamed, N M

    2013-01-01

    The present theoretical study investigates the load capacity and friction coefficient in a three-layered journal bearing lubricated with nanoparticle additive couple stress fluids. The couple stresses effects are analyzed based on Stokes micro-continuum theory. The nondimensional pressure and shear stress expressions are derived using modified Reynolds equation. The nondimensional load capacity increases and the coefficient of friction decreases using nanoparticle additive lubricants with couple stress effects. The three-layered journal bearing performance characteristics are improved with increase in both (i) surface adsorbent fluid film layer thickness and (ii) dynamic viscosity ratio of surface to core layer.

  1. The Influence of Pressure Distribution on the Maximum Values of Stress in FEM Analysis of Plain Bearings

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2016-12-01

    Full Text Available Several methods can be used in the FEM studies to apply the loads on a plain bearing. The paper presents a comparative analysis of maximum stress obtained for three loading scenarios: resultant force applied on the shaft – bearing assembly, variable pressure with sinusoidal distribution applied on the bearing surface, variable pressure with parabolic distribution applied on the bearing surface.

  2. Design and fabrication of gas bearings for Brayton cycle rotating unit

    Science.gov (United States)

    Frost, A.; Tessarzik, J. M.; Arwas, E. B.; Waldron, W. D. (Editor)

    1973-01-01

    Analysis, design, and testing of two types of pivoted pad journal bearings and a spiral-grooved thrust bearing suitable for direct installation into the NASA 2 to 15 KW Brayton Cycle Rotating Unit (BRU) have been accomplished. Both types of tilting pad bearing assemblies are of the preloaded type, consisting of three pads with one pad flexibly mounted. One type utilizes a non-conforming pivot, while the other replaces the conventional spherical pivot with a cruciform flexible member. The thrust bearing is flexure mounted to accommodate static machine mislinement. Test results indicate that both types of journal bearings should satisfy the requirements imposed by the BRU. Hydrostatic tests of the spiral-grooved thrust bearing showed it to be free of pneumatic hammer with as many as 24 orifices over the BRU pressure and load range.

  3. Performance of Infinitely Wide Parabolic and Inclined Slider Bearings Lubricated with Couple Stress or Magnetic Fluids

    Science.gov (United States)

    Oladeinde, Mobolaji Humphrey; Akpobi, John Ajokpaoghene

    2011-10-01

    The hydrodynamic and magnetohydrodynamic (MHD) lubrication problem of infinitely wide inclined and parabolic slider bearings is solved numerically using the finite element method. The bearing configurations are discretized into three-node isoparametric quadratic elements. Stiffness integrals obtained from the weak form of the governing equations are solved using Gauss quadrature to obtain a finite number of stiffness matrices. The global system of equations obtained from enforcing nodal continuity of pressure for the bearings are solved using the Gauss-Seidel iterative scheme with a convergence criterion of 10-10. Numerical computations reveal that, when compared for similar profile and couple stress parameters, greater pressure builds up in a parabolic slider compared to an inclined slider, indicating a greater wedge effect in the parabolic slider. The parabolic slider bearing is also shown to develop a greater load capacity when lubricated with magnetic fluids. The superior performance of parabolic slider bearing is more pronounced at greater Hartmann numbers for identical bearing structural parameters. It is also shown that when load carrying capacity is the yardstick for comparison, the parabolic slider bearings are superior to the inclined bearings when lubricated with couple stress or magnetic lubricants.

  4. Stresses in Dolos Breakwater Armour Units

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.

    1991-01-01

    Breakage of slender unreinforced armour unite is the cause of many breakwater failures. Design diagrams to ensure structural integrity of armour unite such as dolosse and tetrapods have not been available. The article presents results of an analysis of the stresses in dolosse based on model tests...

  5. On Calculation Methods and Results for Straight Cylindrical Roller Bearing Deflection, Stiffness, and Stress

    Science.gov (United States)

    Krantz, Timothy L.

    2011-01-01

    The purpose of this study was to assess some calculation methods for quantifying the relationships of bearing geometry, material properties, load, deflection, stiffness, and stress. The scope of the work was limited to two-dimensional modeling of straight cylindrical roller bearings. Preparations for studies of dynamic response of bearings with damaged surfaces motivated this work. Studies were selected to exercise and build confidence in the numerical tools. Three calculation methods were used in this work. Two of the methods were numerical solutions of the Hertz contact approach. The third method used was a combined finite element surface integral method. Example calculations were done for a single roller loaded between an inner and outer raceway for code verification. Next, a bearing with 13 rollers and all-steel construction was used as an example to do additional code verification, including an assessment of the leading order of accuracy of the finite element and surface integral method. Results from that study show that the method is at least first-order accurate. Those results also show that the contact grid refinement has a more significant influence on precision as compared to the finite element grid refinement. To explore the influence of material properties, the 13-roller bearing was modeled as made from Nitinol 60, a material with very different properties from steel and showing some potential for bearing applications. The codes were exercised to compare contact areas and stress levels for steel and Nitinol 60 bearings operating at equivalent power density. As a step toward modeling the dynamic response of bearings having surface damage, static analyses were completed to simulate a bearing with a spall or similar damage.

  6. Extirpations of grizzly bears in the contiguous United States of America, 1850-2000

    Science.gov (United States)

    Mattson, David J.; Merrill, Troy

    2002-01-01

    We investigated factors associated with the distribution of grizzly bears (Ursus arctos horribilis) in 1850 and their extirpation during 1850–1920 and 1920–1970 in the contiguous United States. We used autologistic regression to describe relations between grizzly bear range in 1850, 1920, and 1970 and potential explanatory factors specified for a comprehensive grid of cells, each 900 km2 in size. We also related persistence, 1920–1970, to range size and shape. Grizzly bear range in 1850 was positively related to occurrence in mountainous ecoregions and the ranges of oaks (Quercus spp.), piñon pines (Pinus edulis and P. monophylla), whitebark pine (P. albicaulis), and bison (Bos bison) and negatively related to occurrence in prairie and hot desert ecoregions. Relations with salmon (Oncorynchus spp.) range and human factors were complex. Persistence of grizzly bear range, 1850–1970, was positively related to occurrence in the Rocky Mountains, whitebark pine range, and local size of grizzly bear range at the beginning of each period, and negatively related to number of humans and the ranges of bison, salmon, and piñon pines. We speculate that foods affected persistence primarily by influencing the frequency of contact between humans and bears. With respect to current conservation, grizzly bears survived from 1920 to 1970 most often where ranges at the beginning of this period were either larger than 20,000 km2 or larger than 7,000 km2 but with a ratio of perimeter to area of grizzly bear range would be as extensive as it is now. Although grizzly bear range in the Yellowstone region is currently the most robust of any to potential future increases in human lethality, bears in this region are threatened by the loss of whitebark pine.

  7. Nonlinear dynamics of a flexible rotor supported by turbulent journal bearings with couple stress fluid

    International Nuclear Information System (INIS)

    Lo, C.-Y.; Chang-Jian, C.-W.

    2008-01-01

    This study presents a dynamic analysis of a rotor supported by two turbulent flow model journal bearings and lubricated with couple stress fluid under nonlinear suspension. The dynamics of the rotor center and bearing center is studied. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The results show that the values of dimensionless parameters l* strongly influence dynamic motions of bearing and rotor centre. It is found that couple stress fluid improve the stability of the system when l* > 0.4 even if the flow of this system is turbulent. We also demonstrated that the dimensionless rotational speed ratios s and the dimensionless unbalance parameter β are also significant system parameters. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided

  8. Reevaluation of the stress-life relation in rolling-element bearings

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.

    1972-01-01

    Four groups of 12.7 millimeter diameter vacuum-degassed AISI 52100 balls were tested, each at a maximum Hertz stress in the range of 4.5 times 10 to 9th power to 6.0 times 10 to 9th power N/m2. Tests were run in the five-ball fatigue tester at a contact angle of 30 deg and a shaft speed of 10,000 rpm. The 10 percent fatigue lives at the four stress levels indicated that fatigue life is inversely proportional to maximum Hertz stress raised to the power of 12. This result agrees with a survey of the literature which suggests that a stress-life exponent of approximately 12 is typical of vacuum-processed bearing steels rather than the exponent of 9 which has been generally accepted by the bearing industry.

  9. 75 FR 53661 - Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom: Final...

    Science.gov (United States)

    2010-09-01

    ... orders remain dispositive. The size or precision grade of a bearing does not influence whether the... also does not influence whether the bearing is covered by the orders. Bearings designed for highly... for individual examination of their sales of the subject merchandise to the United States during the...

  10. On the normal stress effect in grease-lubricated bearing seals

    NARCIS (Netherlands)

    Baart, P.; Lugt, Pieter Martin; Prakash, B.

    2014-01-01

    The film formation in lip seals, due to the non-Newtonian rheology of the lubricant, has been a topic of speculation. Earlier work suggests that normal stresses in grease would be favorable for the film buildup between the seal lip and shaft or bearing ring. In the current article, we evaluate this

  11. Stress Analysis and Fatigue Behaviour of PTFE-Bronze Layered Journal Bearing under Real-Time Dynamic Loading

    Science.gov (United States)

    Duman, M. S.; Kaplan, E.; Cuvalcı, O.

    2018-01-01

    The present paper is based on experimental studies and numerical simulations on the surface fatigue failure of the PTFE-bronze layered journal bearings under real-time loading. ‘Permaglide Plain Bearings P10’ type journal bearings were experimentally tested under different real time dynamic loadings by using real time journal bearing test system in our laboratory. The journal bearing consists of a PTFE-bronze layer approximately 0.32 mm thick on the steel support layer with 2.18 mm thick. Two different approaches have been considered with in experiments: (i) under real- time constant loading with varying bearing widths, (ii) under different real-time loadings at constant bearing widths. Fatigue regions, micro-crack dispersion and stress distributions occurred at the journal bearing were experimentally and theoretically investigated. The relation between fatigue region and pressure distributions were investigated by determining the circumferential pressure distribution under real-time dynamic loadings for the position of every 10° crank angles. In the theoretical part; stress and deformation distributions at the surface of the journal bearing analysed by using finite element methods to determine the relationship between stress and fatigue behaviour. As a result of this study, the maximum oil pressure and fatigue cracks were observed in the most heavily loaded regions of the bearing surface. Experimental results show that PTFE-Bronze layered journal bearings fatigue behaviour is better than the bearings include white metal alloy.

  12. Black bear population and connectivity in the Sky Islands of Mexico and the United States

    Science.gov (United States)

    N. E. Lara-Diaz; C. A. Lopez-Gonzalez; H. Coronel-Arellano; A. Gonzalez-Bernal

    2013-01-01

    The Sky Island region is a mountainous region surrounded by grasslands, deserts and intermountain valleys, located between Mexico and the United States. However, different land management and human impact can have an effect on its wildlife populations. Currently, the border wall poses an immediate threat to the survival of black bears (Ursus americanus), considered an...

  13. Studies on endoparasites of the black bear (Ursus americanus) in the southeastern United States.

    Science.gov (United States)

    Crum, J M; Nettles, V F; Davidson, W R

    1978-04-01

    Examination of 53 black bears (Ursus americanus) from six states in the southeastern United States revealed at least 17 species of endoparasites, including Sarcocystis sp., Spirometra mansonoides (spargana), Macracanthorhynchus ingens, Ancylostoma caninum, Arthrocephalus lotoris, Baylisascaris transfuga, Capillaria aerophila, Capillaria putorii, Crenosoma sp., Cyathospirura sp., Dirofilaria immitis, Gnathostoma sp., Gongylonema pulchrum, microfilariae, Molineus barbatus, Physaloptera sp. and Strongyloides sp. Twelve of these represent new host records for black bear, and two are considered to be new species. Data are presented on prevalence, intensity and geographic distribution of each species. Pathologic effects were associated with infections of spargana of S. mansonoides and adults of C. aerophilia.

  14. 40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units XIII Appendix XIII to Part 266 Protection of Environment... XIII to Part 266—Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units These...

  15. Hydrogeologic Assessment of the East Bear Creek Unit, San LuisNational Wildlife Refuge

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, Nigel W.T.

    2007-07-15

    San Luis National Wildlife Refuge Complex to meetReclamation s obligations for Level 4 water supply under the CentralValley Project Improvement Act. Hydrogeological assessment of the EastBear Creek Unit of the San Luis National Wildlife Refuge was conductedusing a combination of field investigations and a survey of availableliterature from past US Geological Survey Reports and reports by localgeological consultants. Conservative safe yield estimates made using theavailable data show that the East Bear Creek Unit may have sufficientgroundwater resources in the shallow groundwater aquifer to meet aboutbetween 25 percent and 52 percent of its current Level II and between 17percent and 35 percent of its level IV water supply needs. The rate ofsurface and lateral recharge to the Unit and the design of the well fieldand the layout and capacity of pumped wells will decide both thepercentage of annual needs that the shallow aquifer can supply andwhether this yield is sustainable without affecting long-term aquiferquality. In order to further investigate the merits of pumping the nearsurface aquifer, which appears to have reasonable water quality for usewithin the East Bear Creek Unit -- monitoring of the potential sources ofaquifer recharge and the installation of a pilot shallow well would bewarranted. Simple monitoring stations could be installed both upstreamand downstream of both the San Joaquin River and Bear Creek and beinstrumented to measureriver stage, flow and electrical conductivity.Ideally this would be done in conjunction with a shallow pilot well,pumped to supply a portion of the Unit's needs for the wetland inundationperiod.

  16. Modelling of thermal stresses in bearing steel structure generated by electrical current impulses

    Science.gov (United States)

    Birjukovs, M.; Jakovics, A.; Holweger, W.

    2018-05-01

    This work is the study of one particular candidate for white etching crack (WEC) initiation mechanism in wind turbine gearbox bearings: discharge current impulses flowing through bearing steel with associated thermal stresses and material fatigue. Using data/results from previously published works, the authors develop a series of models that are utilized to simulate these processes under various conditions/local microstructure configurations, as well as to verify the results of the previous numerical studies. Presented models show that the resulting stresses are several orders of magnitude below the fatigue limit/yield strength for the parameters used herein. Results and analysis of models provided by Scepanskis, M. et al. also indicate that certain effects predicted in their previous work resulted from a physically unfounded assumption about material thermodynamic properties and numerical model implementation issues.

  17. Possible conservation units of the sun bear (Helarctos malayanus) in Sarawak based on variation of mtDNA control region.

    Science.gov (United States)

    Onuma, Manabu; Suzuki, Masatsugu; Ohtaishi, Noriyuki

    2006-11-01

    The mitochondrial DNA control region of the sun bear (Helarctos malayanus) was sequenced using 21 DNA samples collected from confiscated sun bears to identify conservation units, such as evolutionarily significant units and management units, in Sarawak, Borneo Island. A total of 10 haplotypes were observed, indicating the presence of at least two lineages in the sun bear population in Sarawak. Presumably, these two lineages could represent evolutionarily significant units. However, the geographical distributions of the two lineages remained unknown due to the lack of information regarding the exact capture locations of the confiscated sun bears. It is essential to elucidate the geographical distributions of these lineages in order to create a proper conservation plan for the sun bears in Sarawak. Therefore, further studies examining the haplotype distributions using DNA samples from known localities are essential.

  18. LEUKOCYTE COPING CAPACITY AS A TOOL TO ASSESS CAPTURE- AND HANDLING-INDUCED STRESS IN SCANDINAVIAN BROWN BEARS (URSUS ARCTOS).

    Science.gov (United States)

    Esteruelas, Núria Fandos; Huber, Nikolaus; Evans, Alina L; Zedrosser, Andreas; Cattet, Marc; Palomares, Francisco; Angel, Martine; Swenson, Jon E; Arnemo, Jon M

    2016-04-01

    Brown bears (Ursus arctos) are often captured and handled for research and management purposes. Although the techniques used are potentially stressful for the animals and might have detrimental and long-lasting consequences, it is difficult to assess their physiological impact. Here we report the use of the leukocyte coping capacity (LCC) technique to quantify the acute stress of capture and handling in brown bears in Scandinavia. In April and May 2012 and 2013, we collected venous blood samples and recorded a range of physiological variables to evaluate the effects of capture and the added impact of surgical implantation or removal of transmitters and sensors. We studied 24 brown bears, including 19 that had abdominal surgery. We found 1) LCC values following capture were lower in solitary bears than in bears in family groups suggesting capture caused relatively more stress in solitary bears, 2) ability to cope with handling stress was better (greater LCC values) in bears with good body condition, and 3) LCC values did not appear to be influenced by surgery. Although further evaluation of this technique is required, our preliminary results support the use of the LCC technique as a quantitative measure of stress.

  19. Heat stress assessment in artistic glass units.

    Science.gov (United States)

    d'AMBROSIO Alfano, Francesca Romana; Palella, Boris Igor; Riccio, Giuseppe; Bartalini, Massimo; Strambi, Fabio; Malchaire, Jacques

    2018-04-07

    Heat stress in glass industry is mainly studied in large and highly mechanized manufacturing Units. To the contrary, few studies were carried out in small factories specialized in hand-made products. To stress the need of combined objective and medical surveys in these environments, this paper deals with a simultaneous climatic and physiological investigation of working conditions in artistic crystal glass factories in Tuscany (Italy). The microclimatic monitoring, through a continuous survey has been carried out in early spring. The main physiological parameters (metabolic rate, heart rate, tympanic temperature and water loss) were measured over the whole shifts. The results show that, despite the arduousness of the working conditions, the heat stress levels are physiologically tolerable. The predictions made using the PHS model at the Analysis level described in ISO 15265 agree closely to the observed values, validating the use of PHS model in these conditions. This model was then used to analyse what is likely to be the situation during the summer. It is concluded that the heat constraint will be very high and that some steps must be taken from the spring to monitor closely the exposed workers in the summer and take measures to prevent any heat accident.

  20. Multilayer Finite-Element Model Application to Define the Bearing Structure Element Stress State of Launch Complexes

    Directory of Open Access Journals (Sweden)

    V. A. Zverev

    2016-01-01

    Full Text Available The article objective is to justify the rationale for selecting the multilayer finite element model parameters of the bearing structure of a general-purpose launch complex unit.A typical design element of the launch complex unit, i.e. a mount of the hydraulic or pneumatic cylinder, block, etc. is under consideration. The mount represents a set of the cantilevered axis and external structural cage. The most loaded element of the cage is disk to which a moment is transferred from the cantilevered axis due to actuator effort acting on it.To calculate the stress-strain state of disk was used a finite element method. Five models of disk mount were created. The only difference in models was the number of layers of the finite elements through the thickness of disk. There were models, which had one, three, five, eight, and fourteen layers of finite elements through the thickness of disk. For each model, we calculated the equivalent stresses arising from the action of the test load. Disk models were formed and calculated using the MSC Nastran complex software.The article presents results in the table to show data of equivalent stresses in each of the multi-layered models and graphically to illustrate the changing equivalent stresses through the thickness of disk.Based on these results we have given advice on selecting the proper number of layers in the model allowing a desirable accuracy of results with the lowest run time. In addition, it is concluded that there is a need to use the multi-layer models in assessing the performance of structural elements in case the stress exceeds the allowable one in their surface layers.

  1. Spotted hyena and steppe lion predation behaviours on cave bears of Europe - ?Late Quaternary cave bear extinction as result of predator stress

    Science.gov (United States)

    Diedrich, Cajus G.

    2010-05-01

    high alpine regions the leopard Panthera pardus seem to have used the ecological niche of the absent hyenas (Diedrich 2009d, in review a). At open air sites cave bear scavenging by the largest Late Quaternary predators were proven, too (Diedrich 2006, 2009e). The predation stress caused by the three main and largest Late Quaternary predators seem to have provided cave bears to hibernate often deeply in many European caves, and here especially in larger and longer cave systems (e.g. Diedrich et al 2009, in review, Diedrich and Moldovan 2010) to protect themselves against the largest Quaternary predators. In conflicts with those large felids must have been killed by adult cave bears, which explains why those predator carcasses remained as complete skeletons or as partly disarticulated ones even deep in caves all over Europe which were finally not scavenged by the herbivorous cave bears (Diedrich in review). In such cave bear den caves the amount of lion bones generally take only 1-3% of the total bone amount being highly dominated by cave bear bones (Diedrich 2009c, in review). Lions and hyenas seem to have focussed onto the hunt of cave bears all over Europe, especially with the reduction of the biomass in the open environments at the maximum cold period during around 26.000-24.000 BP (Solutrean). The slow extinction of their largest prey was an important motor of the predation pressure onto cave bears. This might be one reason for the cave bear extinction in the final Late Quaternary (early Late Weichselian, maximum cold period) at least in northern Europe, but it seem to have happened in a combination of climatic change, and also human impact (cf. Diedrich, this volume). References Diedrich, C., 2005. Cracking and nibbling marks as indicators for the Upper Pleistocene spotted hyena as a scavenger of cave bear (Ursus spelaeus Rosenmüller, 1794) carcasses in the Perick Caves den of Northwest Germany. Abhandlungen der Naturhistorischen Gesellschaft Nürnberg, 45, 73

  2. Roller bearing geometry design

    Science.gov (United States)

    Savage, M.; Pinkston, B. H. W.

    1976-01-01

    A theory of kinematic stabilization of rolling cylinders is extended and applied to the design of cylindrical roller bearings. The kinematic stabilization mechanism puts a reverse skew into the rolling elements by changing the roller taper. Twelve basic bearing modification designs are identified amd modeled. Four have single transverse convex curvature in their rollers while eight have rollers which have compound transverse curvature made up of a central cylindrical band surrounded by symmetric bands with slope and transverse curvature. The bearing designs are modeled for restoring torque per unit axial displacement, contact stress capacity, and contact area including dynamic loading, misalignment sensitivity and roller proportion. Design programs are available which size the single transverse curvature roller designs for a series of roller slopes and load separations and which design the compound roller bearings for a series of slopes and transverse radii of curvature. The compound rollers are proportioned to have equal contact stresses and minimum size. Design examples are also given.

  3. Strength evolution of simulated carbonate-bearing faults: The role of normal stress and slip velocity

    Science.gov (United States)

    Mercuri, Marco; Scuderi, Marco Maria; Tesei, Telemaco; Carminati, Eugenio; Collettini, Cristiano

    2018-04-01

    A great number of earthquakes occur within thick carbonate sequences in the shallow crust. At the same time, carbonate fault rocks exhumed from a depth plasticity). We performed friction experiments on water-saturated simulated carbonate-bearing faults for a wide range of normal stresses (from 5 to 120 MPa) and slip velocities (from 0.3 to 100 μm/s). At high normal stresses (σn > 20 MPa) fault gouges undergo strain-weakening, that is more pronounced at slow slip velocities, and causes a significant reduction of frictional strength, from μ = 0.7 to μ = 0.47. Microstructural analysis show that fault gouge weakening is driven by deformation accommodated by cataclasis and pressure-insensitive deformation processes (pressure solution and granular plasticity) that become more efficient at slow slip velocity. The reduction in frictional strength caused by strain weakening behaviour promoted by the activation of pressure-insensitive deformation might play a significant role in carbonate-bearing faults mechanics.

  4. Dynamic Model for Hydro-Turbine Generator Units Based on a Database Method for Guide Bearings

    Directory of Open Access Journals (Sweden)

    Yong Xu

    2013-01-01

    Full Text Available A suitable dynamic model of rotor system is of great significance not only for supplying knowledge of the fault mechanism, but also for assisting in machine health monitoring research. Many techniques have been developed for properly modeling the radial vibration of large hydro-turbine generator units. However, an applicable dynamic model has not yet been reported in literature due to the complexity of the boundary conditions and exciting forces. In this paper, a finite element (FE rotor dynamic model of radial vibration taking account of operating conditions is proposed. A brief and practical database method is employed to model the guide bearing. Taking advantage of the method, rotating speed and bearing clearance can be considered in the model. A novel algorithm, which can take account of both transient and steady-state analysis, is proposed to solve the model. Dynamic response for rotor model of 125 MW hydro-turbine generator units in Gezhouba Power Station is simulated. Field data from Optimal Maintenance Information System for Hydro power plants (HOMIS are analyzed compared with the simulation. Results illustrate the application value of the model in providing knowledge of the fault mechanism and in failure diagnosis.

  5. Development and application of an antibody-based protein microarray to assess physiological stress in grizzly bears (Ursus arctos).

    Science.gov (United States)

    Carlson, Ruth I; Cattet, Marc R L; Sarauer, Bryan L; Nielsen, Scott E; Boulanger, John; Stenhouse, Gordon B; Janz, David M

    2016-01-01

    A novel antibody-based protein microarray was developed that simultaneously determines expression of 31 stress-associated proteins in skin samples collected from free-ranging grizzly bears (Ursus arctos) in Alberta, Canada. The microarray determines proteins belonging to four broad functional categories associated with stress physiology: hypothalamic-pituitary-adrenal axis proteins, apoptosis/cell cycle proteins, cellular stress/proteotoxicity proteins and oxidative stress/inflammation proteins. Small skin samples (50-100 mg) were collected from captured bears using biopsy punches. Proteins were isolated and labelled with fluorescent dyes, with labelled protein homogenates loaded onto microarrays to hybridize with antibodies. Relative protein expression was determined by comparison with a pooled standard skin sample. The assay was sensitive, requiring 80 µg of protein per sample to be run in triplicate on the microarray. Intra-array and inter-array coefficients of variation for individual proteins were generally bears. This suggests that remotely delivered biopsy darts could be used in future sampling. Using generalized linear mixed models, certain proteins within each functional category demonstrated altered expression with respect to differences in year, season, geographical sampling location within Alberta and bear biological parameters, suggesting that these general variables may influence expression of specific proteins in the microarray. Our goal is to apply the protein microarray as a conservation physiology tool that can detect, evaluate and monitor physiological stress in grizzly bears and other species at risk over time in response to environmental change.

  6. Stress distribution and pressure-bearing capacity of a high-pressure split-cylinder die with prism cavity

    Science.gov (United States)

    Zhao, Liang; Li, Mingzhe; Wang, Liyan; Qu, Erhu; Yi, Zhuo

    2018-03-01

    A novel high-pressure belt-type die with a split-type cylinder is investigated with respect to extending its lifetime and improving its pressure bearing capacity. Specifically, a tungsten carbide cylinder is split into several parts along the radial direction with a prism-type cavity. In this paper, the cylinders with different split numbers are chosen to study the stress distribution and compare them with the traditional belt-type die. The simulation results indicate that the split cylinder has much smaller stress than those in the belt-type cylinder, and the statistical analysis reveals that the split-pressure cylinder is able to bear higher pressure. Experimental tests also show that the high-pressure die with a split cylinder and prism cavity has a stronger pressure-bearing capacity than a belt-type die. The split cylinder has advantages of easy manufacturing, high pressure bearing capacity, and replaceable performance.

  7. 76 FR 35401 - Ball Bearings and Parts Thereof From Japan and the United Kingdom: Notice of Court Decision Not...

    Science.gov (United States)

    2011-06-17

    ...On June 1, 2005, the Department of Commerce (the Department) initiated and the International Trade Commission (ITC) instituted the second sunset reviews of the antidumping duty orders on ball bearings and parts thereof from Japan and the United Kingdom. On April 20, 2011, the Court of International Trade (CIT) entered its final judgment sustaining the ITC's remand redetermination that revocation of the antidumping duty orders on ball bearings and parts thereof from Japan and the United Kingdom would not be likely to lead to continuation or recurrence of material injury to an industry in the United States within a reasonably foreseeable time.

  8. Stress and reproductive hormones in grizzly bears reflect nutritional benefits and social consequences of a salmon foraging niche.

    Science.gov (United States)

    Bryan, Heather M; Darimont, Chris T; Paquet, Paul C; Wynne-Edwards, Katherine E; Smits, Judit E G

    2013-01-01

    Physiological indicators of social and nutritional stress can provide insight into the responses of species to changes in food availability. In coastal British Columbia, Canada, grizzly bears evolved with spawning salmon as an abundant but spatially and temporally constrained food source. Recent and dramatic declines in salmon might have negative consequences on bear health and ultimately fitness. To examine broadly the chronic endocrine effects of a salmon niche, we compared cortisol, progesterone, and testosterone levels in hair from salmon-eating bears from coastal BC (n = 75) with the levels in a reference population from interior BC lacking access to salmon (n = 42). As predicted, testosterone was higher in coastal bears of both sexes relative to interior bears, possibly reflecting higher social density on the coast mediated by salmon availability. We also investigated associations between the amount of salmon individual bears consumed (as measured by stable isotope analysis) and cortisol and testosterone in hair. Also as predicted, cortisol decreased with increasing dietary salmon and was higher after a year of low dietary salmon than after a year of high dietary salmon. These findings at two spatial scales suggest that coastal bears might experience nutritional or social stress in response to on-going salmon declines, providing novel insights into the effects of resource availability on fitness-related physiology.

  9. Stress and reproductive hormones in grizzly bears reflect nutritional benefits and social consequences of a salmon foraging niche.

    Directory of Open Access Journals (Sweden)

    Heather M Bryan

    Full Text Available Physiological indicators of social and nutritional stress can provide insight into the responses of species to changes in food availability. In coastal British Columbia, Canada, grizzly bears evolved with spawning salmon as an abundant but spatially and temporally constrained food source. Recent and dramatic declines in salmon might have negative consequences on bear health and ultimately fitness. To examine broadly the chronic endocrine effects of a salmon niche, we compared cortisol, progesterone, and testosterone levels in hair from salmon-eating bears from coastal BC (n = 75 with the levels in a reference population from interior BC lacking access to salmon (n = 42. As predicted, testosterone was higher in coastal bears of both sexes relative to interior bears, possibly reflecting higher social density on the coast mediated by salmon availability. We also investigated associations between the amount of salmon individual bears consumed (as measured by stable isotope analysis and cortisol and testosterone in hair. Also as predicted, cortisol decreased with increasing dietary salmon and was higher after a year of low dietary salmon than after a year of high dietary salmon. These findings at two spatial scales suggest that coastal bears might experience nutritional or social stress in response to on-going salmon declines, providing novel insights into the effects of resource availability on fitness-related physiology.

  10. Unit Reconstitutions: Combat Stress as an Indicator of Unit Effectiveness

    Science.gov (United States)

    2014-06-13

    doctrinally “Combat and Operational Stress Reactions:” A. Shell shock B. War neurosis C. Battle fatigue D. Combat exhaustion E. Combat stress F...... neurosis . The approach that evolved–proximity, immediacy, and expectancy–was a formula that incorporated some of the best practices to increase the

  11. Approximate solution of oil film load-carrying capacity of turbulent journal bearing with couple stress flow

    Science.gov (United States)

    Zhang, Yongfang; Wu, Peng; Guo, Bo; Lü, Yanjun; Liu, Fuxi; Yu, Yingtian

    2015-01-01

    The instability of the rotor dynamic system supported by oil journal bearing is encountered frequently, such as the half-speed whirl of the rotor, which is caused by oil film lubricant with nonlinearity. Currently, more attention is paid to the physical characteristics of oil film due to an oil-lubricated journal bearing being the important supporting component of the bearing-rotor systems and its nonlinear nature. In order to analyze the lubrication characteristics of journal bearings efficiently and save computational efforts, an approximate solution of nonlinear oil film forces of a finite length turbulent journal bearing with couple stress flow is proposed based on Sommerfeld and Ocvirk numbers. Reynolds equation in lubrication of a finite length turbulent journal bearing is solved based on multi-parametric principle. Load-carrying capacity of nonlinear oil film is obtained, and the results obtained by different methods are compared. The validation of the proposed method is verified, meanwhile, the relationships of load-carrying capacity versus eccentricity ratio and width-to-diameter ratio under turbulent and couple stress working conditions are analyzed. The numerical results show that both couple stress flow and eccentricity ratio have obvious influence on oil film pressure distribution, and the proposed method approximates the load-carrying capacity of turbulent journal bearings efficiently with various width-to-diameter ratios. This research proposes an approximate solution of oil film load-carrying capacity of turbulent journal bearings with different width-to-diameter ratios, which are suitable for high eccentricity ratios and heavy loads.

  12. Electrophysiological assessment of water stress in fruit-bearing woody plants.

    Science.gov (United States)

    Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

    2014-06-15

    Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a

  13. Distribution of Selenium and Oxidative Stress in Breast Tumor-Bearing Mice

    Directory of Open Access Journals (Sweden)

    Pei-Chung Chen

    2013-02-01

    Full Text Available The present study investigated the effects of breast tumors on the blood and tissue distribution of essential trace mineral selenium (Se, and oxidative stress status of mice. Female 10-week-old BALB/cByJNarl mice were randomly assigned into control (CNL and breast tumor-bearing (TB groups. TB mice were injected subcutaneously into the right hind thigh with 5 × 106 EMT6 mouse mammary tumor cells. After 22 days, we measured Se concentrations, Se-dependent glutathione peroxidase (GPx activities, and malondialdehyde (MDA products (indicator of oxidative stress in plasma, various tissues, and plasma vascular endothelial growth factor (VEGF concentrations. There were no significant differences in body weights and daily intake between both groups. Compared with the CNL group, TB mice have decreases in plasma Se concentrations and GPx activities, as well as higher plasma VEGF and MDA concentrations. Plasma Se concentrations were also negatively correlated with plasma MDA and VEGF concentrations. Furthermore, tissue Se concentrations and GPx activities in TB animals were lower; whereas the MDA concentrations higher in various tissues including liver, kidney, brain, lung, spleen, and thymic tissues. In conclusion, disruption of Se homeostasis critically reflects oxidative stress in target tissues, thus may increase the risk for progression of breast cancer and metastasis.

  14. Contact stresses, pressure and area in a fixed-bearing total ankle replacement: a finite element analysis.

    Science.gov (United States)

    Martinelli, Nicolo; Baretta, Silvia; Pagano, Jenny; Bianchi, Alberto; Villa, Tomaso; Casaroli, Gloria; Galbusera, Fabio

    2017-11-25

    Mobile-bearing ankle implants with good clinical results continued to increase the popularity of total ankle arthroplasty to address endstage ankle osteoarthritis preserving joint movement. Alternative solutions used fixed-bearing designs, which increase stability and reduce the risk of bearing dislocation, but with a theoretical increase of contact stresses leading to a higher polyethylene wear. The purpose of this study was to investigate the contact stresses, pressure and area in the polyethylene component of a new total ankle replacement with a fixed-bearing design, using 3D finite element analysis. A three-dimensional finite element model of the Zimmer Trabecular Metal Total Ankle was developed and assembled based on computed tomography images. Three different sizes of the polyethylene insert were modeled, and a finite element analysis was conducted to investigate the contact pressure, the von Mises stresses and the contact area of the polyethylene component during the stance phase of the gait cycle. The peak value of pressure was found in the anterior region of the articulating surface, where it reached 19.8 MPa at 40% of the gait cycle. The average contact pressure during the stance phase was 6.9 MPa. The maximum von Mises stress of 14.1 MPa was reached at 40% of the gait cycle in the anterior section. In the central section, the maximum von Mises stress of 10.8 MPa was reached at 37% of the gait cycle, whereas in the posterior section the maximum stress of 5.4 MPa was reached at the end of the stance phase. The new fixed-bearing total ankle replacement showed a safe mechanical behavior and many clinical advantages. However, advanced models to quantitatively estimate the wear are need. To the light of the clinical advantages, we conclude that the presented prosthesis is a good alternative to the other products present in the market.

  15. Precambrian uranium-bearing quartz-pebble conglomerates: exploration model and United States resource potential

    International Nuclear Information System (INIS)

    Houston, R.S.; Karlstrom, K.E.

    1979-11-01

    Uranium has been discovered in fluvial quartz-pebble conglomerates in most of the Precambrian shield areas of the world, including the Canadian, African, South American, Indian, Baltic, and Australian shields. Occurrences in these and other areas are shown. Two of these occurrences, the Huronian supergroup of Canada and the Witwatersrand deposit of South Africa contain 20 to 30 percent of the planet's known uranium reserves. Thus it is critical that we understand the origin of these deposits and develop exploration models that can aid in finding new deposits. Inasmuch as these uranium-bearing conglomerates are confined almost entirely to rocks of Precambrian age, Part I of this review begins with a discussion of Precambrian geology as it applies to the conglomerates. This is followed by a discussion of genetic concepts, a discussion of unresolved problems, and finally a suggested exploration model. Part II summarizes known and potential occurrences of Precambrian fossil placers in the world and evaluates them in terms of the suggested exploration model. Part III discusses the potential for important Precambrian fossil-placer uranium deposits in the United States and includes suggestions that may be helpful in establishing an exploration program in this country. Part III also brings together new (1975-1978) data on uranium occurrences in the Precambrian of the Wyoming Province. Part IV is a complete bibliography of Precambrian fossil placers, divided according to geographical areas. In total, this paper is designed to be a comprehensive review of Precambrian uranium-bearing fossil placers which will be of use to uranium explorationists and to students of Precambrian geology

  16. Precambrian uranium-bearing quartz-pebble conglomerates: exploration model and United States resource potential

    Energy Technology Data Exchange (ETDEWEB)

    Houston, R.S.; Karlstrom, K.E.

    1979-11-01

    Uranium has been discovered in fluvial quartz-pebble conglomerates in most of the Precambrian shield areas of the world, including the Canadian, African, South American, Indian, Baltic, and Australian shields. Occurrences in these and other areas are shown. Two of these occurrences, the Huronian supergroup of Canada and the Witwatersrand deposit of South Africa contain 20 to 30 percent of the planet's known uranium reserves. Thus it is critical that we understand the origin of these deposits and develop exploration models that can aid in finding new deposits. Inasmuch as these uranium-bearing conglomerates are confined almost entirely to rocks of Precambrian age, Part I of this review begins with a discussion of Precambrian geology as it applies to the conglomerates. This is followed by a discussion of genetic concepts, a discussion of unresolved problems, and finally a suggested exploration model. Part II summarizes known and potential occurrences of Precambrian fossil placers in the world and evaluates them in terms of the suggested exploration model. Part III discusses the potential for important Precambrian fossil-placer uranium deposits in the United States and includes suggestions that may be helpful in establishing an exploration program in this country. Part III also brings together new (1975-1978) data on uranium occurrences in the Precambrian of the Wyoming Province. Part IV is a complete bibliography of Precambrian fossil placers, divided according to geographical areas. In total, this paper is designed to be a comprehensive review of Precambrian uranium-bearing fossil placers which will be of use to uranium explorationists and to students of Precambrian geology.

  17. Effect of stress management interventions on job stress among nurses working in critical care units.

    Science.gov (United States)

    Light Irin, C; Bincy, R

    2012-01-01

    Stress in nurses affects their health and increases absenteeism, attrition rate, injury claims, infection rates and errors in treating patients. This in turn significantly increases the cost of employment in healthcare units. Proper management of stress ensures greater efficiency at work place and improved wellbeing of the employee. Therefore, a pre-experimental study was conducted among 30 Critical Care Unit nurses working inMedical College Hospital, Thiruvananthapuram, (Kerala) to assess the effect of stress management interventions such as Job Stress Awareness, Assertiveness Training, Time Management, andProgressive Muscle Relaxation on job stress. The results showed that caring for patients, general job requirements and workload were the major sources of stress for the nurses. The level of severe stress was reduced from 60 percent to 20 percent during post-test. The Stress Management Interventions were statistically effective in reducing the stress of nurses at p<0.001 level.

  18. Genetic Characterization of Sarcoptes scabiei from Black Bears (Ursus americanus) and Other Hosts in the Eastern United States.

    Science.gov (United States)

    Peltier, Sarah K; Brown, Justin D; Ternent, Mark; Niedringhaus, Kevin D; Schuler, Krysten; Bunting, Elizabeth M; Kirchgessner, Megan; Yabsley, Michael J

    2017-10-01

    Since the early 1990s there has been an increase in the number of cases and geographic expansion of severe mange in the black bear (Ursus americanus) population in Pennsylvania. Although there are 3 species of mites associated with mange in bears, Sarcoptes scabiei has been identified as the etiologic agent in these Pennsylvania cases. Historically, S. scabiei-associated mange in bears has been uncommon and sporadic, although it is widespread and relatively common in canid populations. To better understand this recent emergence of sarcoptic mange in bears in Pennsylvania and nearby states, we genetically characterized S. scabiei samples from black bears in the eastern United States. These sequences were compared with newly acquired S. scabiei sequences from wild canids (red fox [Vulpes vulpes] and coyote [Canis latrans]) and a porcupine (Erethizon dorsatum) from Pennsylvania and Kentucky and also existing sequences in GenBank. The internal transcribed spacer (ITS)-2 region and cytochrome c oxidase subunit 1 (cox1) gene were amplified and sequenced. Twenty-four ITS-2 sequences were obtained from mites from bears (n = 16), red fox (n = 5), coyote (n = 2), and a porcupine. The sequences from bear samples were identical to each other or differed only at polymorphic bases, whereas S. scabiei from canids were more variable, but 2 were identical to S. scabiei sequences from bears. Eighteen cox1 sequences obtained from mites from bears represented 6 novel haplotypes. Phylogenetic analysis of cox1 sequences revealed 4 clades: 2 clades of mites of human origin from Panama or Australia, a clade of mites from rabbits from China, and a large unresolved clade that included the remaining S. scabiei sequences from various hosts and regions, including sequences from the bears from the current study. Although the cox1 gene was more variable than the ITS-2, phylogenetic analyses failed to detect any clustering of S. scabiei from eastern U.S. hosts. Rather, sequences from black bears

  19. 75 FR 26920 - Ball Bearings and Parts Thereof from France, Germany, Italy, Japan, and the United Kingdom...

    Science.gov (United States)

    2010-05-13

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-427-801, A-428-801, A-475-801, A-588-804, A-412-801] Ball Bearings and Parts Thereof from France, Germany, Italy, Japan, and the United Kingdom: Preliminary Results of Antidumping Duty Administrative Reviews, Preliminary Results of Changed-Circumstances Review, Rescission of Antidumpin...

  20. 76 FR 2647 - Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom...

    Science.gov (United States)

    2011-01-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-427-801, A-428-801, A-475-801, A-588-804, A-412-801] Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom: Extension of Time Limit for Preliminary Results of Antidumping Duty Administrative Reviews AGENCY: Import Administration, International Trade...

  1. 75 FR 2108 - Ball Bearings and Parts Thereof from France, Germany, Italy, Japan, and the United Kingdom...

    Science.gov (United States)

    2010-01-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-427-801, A-428-801, A-475-801, A-588-804, A-412-801] Ball Bearings and Parts Thereof from France, Germany, Italy, Japan, and the United Kingdom: Extension of Time Limit for Preliminary Results of Antidumping Duty Administrative Reviews AGENCY: Import Administration, International Trade...

  2. 76 FR 15940 - Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom...

    Science.gov (United States)

    2011-03-22

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-427-801, A-428-801, A-475-801, A-588-804, A-412-801] Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom: Extension of Time Limit for Preliminary Results of Antidumping Duty Administrative and Changed-Circumstances Reviews AGENCY: Import...

  3. Weight bearing cone beam CT scan versus gravity stress radiography for analysis of supination external rotation injuries of the ankle.

    Science.gov (United States)

    Marzo, John M; Kluczynski, Melissa A; Clyde, Corey; Anders, Mark J; Mutty, Christopher E; Ritter, Christopher A

    2017-12-01

    For AO 44-B2 ankle fractures of uncertain stability, the current diagnostic standard is to obtain a gravity stress radiograph, but some have advocated for the use of weight-bearing radiographs. The primary aim was to compare measures of medial clear space (MCS) on weight-bearing cone beam computed tomography (CBCT) scans versus gravity stress radiographs for determining the state of stability of ankle fractures classified as AO SER 44-B2 or Weber B. The secondary aim was to evaluate the details offered by CBCT scans with respect to other findings that may be relevant to patient care. Nine patients were enrolled in this cross-sectional study between April 2016 and February 2017 if they had an AO SER 44-B2 fracture of uncertain stability, had a gravity stress radiograph, and were able to undergo CT scan within seven days. The width of the MCS was measured at the level of the talar dome on all radiographs and at the mid coronal slice on CT. Wilcoxon signed-ranks tests were used to compare MCS between initial radiographs, gravity stress radiographs and weight-bearing CBCT scans. MCS on weight-bearing CBCT scan (1.41±0.41 mm) was significantly less than standard radiographs (3.28±1.63 mm, P=0.004) and gravity stress radiographs (5.82±1.93 mm, P=0.02). There was no statistically significant difference in MCS measured on standard radiographs versus gravity stress radiographs (P=0.11). Detailed review of the multiplanar CT images revealed less than perfect anatomical reduction of the fractures, with residual fibular shortening, posterior displacement, and fracture fragments in the incisura as typical findings. Similar to weight-bearing radiographs, weight-bearing CBCT scan can predict stability of AO 44-B2 ankle fractures by showing restoration of the MCS, and might be used to indicate patients for non-operative treatment. None of the fractures imaged in this study were perfectly reduced however, and further clinical research is necessary to determine if any of the

  4. Covalent Organic Framework Material bearing Phloroglucinol Building Units as a Potent Anticancer Agent

    KAUST Repository

    Bhanja, Piyali; Mishra, Snehasis; Manna, Krishnendu; Mallick, Arijit; Das Saha, Krishna; Bhaumik, Asim

    2017-01-01

    Covalent organic frameworks (COFs) having periodicity in pores of nanoscale dimensions can be suitably designed for the organic building units bearing reactive functional groups at their surfaces. Thus, they are an attractive option as an anticancer agent to overcome the limitations of chemotherapy. Herein, we first report a new porous biodegradable nitrogen containing COF material, EDTFP-1 (ethylenedianiline-triformyl phloroglucinol), synthesized using 4,4'-ethylenedianiline and 2,4,6-triformylphloroglucinol via Schiff base condensation reaction. EDTFP-1 exhibited 3D-hexagonal porous structure with average pores of ca. 1.5 nm dimension. Here, we have explored the anti-cancer potentiality of EDTFP-1. Result demonstrated an enhanced cytotoxicity was observed against four cancer cells HCT 116, HepG2, A549, and MIA-Paca2 with significant lower IC50 on HCT116 cells. Additionally, EDTFP-1-induced cell death was associated with the characteristic apoptotic changes like cell membrane blebbing, nuclear DNA fragmentation, externalization of phosphatidylserine from the cell membrane followed by a loss of mitochondrial membrane potential as well as modulation of pro and anti-apoptotic proteins. Further, the result depicted a direct correlation between the generations of ROS with mitochondrial-dependant apoptosis through the involvement of p53 phosphorylation upon EDTFP-1 induction, suggesting this COF material is a novel chemotherapeutic agent for cancer treatment.

  5. Covalent Organic Framework Material bearing Phloroglucinol Building Units as a Potent Anticancer Agent

    KAUST Repository

    Bhanja, Piyali

    2017-08-23

    Covalent organic frameworks (COFs) having periodicity in pores of nanoscale dimensions can be suitably designed for the organic building units bearing reactive functional groups at their surfaces. Thus, they are an attractive option as an anticancer agent to overcome the limitations of chemotherapy. Herein, we first report a new porous biodegradable nitrogen containing COF material, EDTFP-1 (ethylenedianiline-triformyl phloroglucinol), synthesized using 4,4\\'-ethylenedianiline and 2,4,6-triformylphloroglucinol via Schiff base condensation reaction. EDTFP-1 exhibited 3D-hexagonal porous structure with average pores of ca. 1.5 nm dimension. Here, we have explored the anti-cancer potentiality of EDTFP-1. Result demonstrated an enhanced cytotoxicity was observed against four cancer cells HCT 116, HepG2, A549, and MIA-Paca2 with significant lower IC50 on HCT116 cells. Additionally, EDTFP-1-induced cell death was associated with the characteristic apoptotic changes like cell membrane blebbing, nuclear DNA fragmentation, externalization of phosphatidylserine from the cell membrane followed by a loss of mitochondrial membrane potential as well as modulation of pro and anti-apoptotic proteins. Further, the result depicted a direct correlation between the generations of ROS with mitochondrial-dependant apoptosis through the involvement of p53 phosphorylation upon EDTFP-1 induction, suggesting this COF material is a novel chemotherapeutic agent for cancer treatment.

  6. Bearing Stress at Failure of Double-Lap Hybrid Joints in Woven Fabric Kenaf Fiber Composite Plates under Quasi-static Loading

    Directory of Open Access Journals (Sweden)

    Lee Sim Yee

    2017-01-01

    Full Text Available The present paper is focused on the bearing stress at failure of double-lap woven fabric kenaf fiber reinforced polymer (KFRP hybrid bonded-bolted joints in experimental frameworks. The effects of different normalized plate width (plate width/hole diameter, W/d, lay-up types and bolt loads were incorporated in current study as specified in testing series. Generally, hybrid joint coupons separated within adhesive layer prior to net-tension failure or bearing/net-tension failure. The bearing stress at failure increased as W/d ratio increment, critical W/d is given as four and three in clamped and finger tight condition respectively. Lay-up types present insignificant effect to bearing stress at failure due to low volume fiber fraction in kenaf fiber composites. Combination of thicker and clamped conditions plate demonstrated greater bearing stress than equivalent finger-tight (FT conditions due to higher load transferred from friction, as expected.

  7. Stress Levels of Nurses in Oncology Outpatient Units.

    Science.gov (United States)

    Ko, Woonhwa; Kiser-Larson, Norma

    2016-04-01

    Oncology nursing is often a source of substantial stress for nurses. Many nurses, particularly novice nurses, have inadequate preparation to care for patients at the end of life and their families. Unless nurses prevent or manage work-related stress by using effective coping strategies, oncology nursing staff will continue to suffer from burnout and compassion fatigue. The purpose of this article is to identify stress levels and stressful factors of nurses working in oncology outpatient units and to explore coping behaviors for work-related stress of oncology staff nurses in outpatient units. A descriptive, cross-sectional design was used to identify stress levels and stressful factors for outpatient oncology nurses, investigate differences in stress levels among nurses' demographic characteristics, and explore coping behaviors of the nurses. Study participants (N = 40) included RNs and licensed practical nurses who completed the Nursing Stress Scale, three open-ended questions, and a demographic questionnaire. The highest sources of stress were workload and patient death and dying. Demographic variables of age and work experience in nursing showed a significant positive relationship to work-related stress scores. The three most frequently used coping behaviors were verbalizing, exercising or relaxing, and taking time for self. Continuing education programs on stress management are highly recommended. Outpatient oncology nurses should be nurtured and supported through tailored interventions at multiple levels to help them find effective coping strategies and develop self-care competencies. Although younger and less experienced nurses had lower mean stress scores than older and more experienced nurses, the continuing education programs and tailored interventions would be helpful for all oncology nursing staff.

  8. Increased stress in Asiatic black bears relates to food limitation, crop raiding, and foraging beyond nature reserve boundaries in China

    Directory of Open Access Journals (Sweden)

    Karl D. Malcolm

    2014-12-01

    Full Text Available Asiatic black bears (Ursus thibetanus are declining throughout much of their range. In China they are partially protected by a nature reserve system and rely heavily on hard mast as a food source prior to winter denning. Bears may compensate for mast shortages by raiding agricultural crops and killing livestock, mainly outside reserves where they are exposed to increased threats of poaching. We hypothesized that stress would vary with availability of high-quality refugia and fluctuations in mast abundance. We collected fecal samples from free-ranging bears in and around nature reserves in southwestern China, recorded habitat characteristics at each fecal sample location, and quantified abundance of hard mast. We used feces for genetic and endocrine analysis and identified 106 individuals. Feces collected outside reserves, or in agricultural fields within reserves, contained elevated concentrations of glucocorticoid metabolites compared to samples collected in intact, mast-producing forests within reserves. Relationships with habitat variables indicated that the hypothalamic–pituitary–adrenal (HPA axis of the Asiatic black bear is responsive to human activity, abundance of hard mast, extent of forest cover, and quality of diet. Our findings demonstrate biological reactions of a large mammal to variable forest quality, human threats, and foraging relative to boundaries of protected areas. Keywords: Agriculture, Fecal glucocorticoids, Mast, Poaching, Protected areas, Stress

  9. Creatine supplementation prevents hyperhomocysteinemia, oxidative stress and cancer-induced cachexia progression in Walker-256 tumor-bearing rats.

    Science.gov (United States)

    Deminice, Rafael; Cella, Paola Sanches; Padilha, Camila S; Borges, Fernando H; da Silva, Lilian Eslaine Costa Mendes; Campos-Ferraz, Patrícia L; Jordao, Alceu Afonso; Robinson, Jason Lorne; Bertolo, Robert F; Cecchini, Rubens; Guarnier, Flávia Alessandra

    2016-08-01

    The purpose of this study was to investigate (1) the impact of tumor growth on homocysteine (Hcy) metabolism, liver oxidative stress and cancer cachexia and, (2) the potential benefits of creatine supplementation in Walker-256 tumor-bearing rats. Three experiments were conducted. First, rats were killed on days 5 (D5), 10 (D10) and 14 (D14) after tumor implantation. In experiment 2, rats were randomly assigned to three groups designated as control (C), tumor-bearing (T) and tumor-bearing supplemented with creatine (TCr). A life span experiment was conducted as the third experiment. Creatine was supplied in drinking water for 21 days (8 g/L) in all cases. Tumor implantation consisted of a suspension of Walker-256 cells (8.0 × 10(7) cells in 0.5 mL of PBS). The progressive increase (P creatine supplementation promoted a 28 % reduction of tumor weight (P Creatine supplementation was unable to decrease Hcy concentration and to increase SAM/SAH ratio in tumor tissue. These data suggest that creatine effects on hepatic impaired Hcy metabolism promoted by tumor cell inoculation are responsible to decrease plasma Hcy in tumor-bearing rats. In conclusion, Walker-256 tumor growth is associated with progressive hyperhomocysteinemia, body weight loss and liver oxidative stress in rats. Creatine supplementation, however, prevented these tumor-associated perturbations.

  10. Performance of two-lobe hole-entry hybrid journal bearing system under the combined influence of textured surface and couple stress lubricant

    Science.gov (United States)

    Khatri, Chandra B.; Sharma, Satish C.

    2018-02-01

    Textured surface in journal bearings is becoming an important area of investigation during the last few years. Surface textures have the shapes of micro-dimple with a small diameter and depth having order of magnitude of bearing clearance. This paper presents the influence of couple stress lubricant on the circular and non-circular hole-entry hybrid journal bearing system and reports the comparative study between the textured and non-textured circular/non-circular hybrid journal bearing system. The governing Reynolds equation has been modified for the couple stress lubricant flow in the clearance of bearing and journal. The FEM technique has been applied to solve the modified Reynolds equation together with restrictor flow equation. The numerically simulated results indicate that the influence of couple stress lubricant is significantly more in textured journal bearing than that of non-textured journal bearing. Further, it has been observed that the textured two-lobe (δ = 1.1) hybrid journal bearing lubricated with couple stress lubricant provides larger values of fluid film stiffness coefficients and stability threshold speed against other bearings studied in the present paper.

  11. Influence of uneven settlements of the curved glulam frames’ bearings on the cornice node’s stress-strain state

    Directory of Open Access Journals (Sweden)

    Денис Віталійович Михайловський

    2016-07-01

    Full Text Available Comparison analysis of the cornice node’s stress of three-hinged curved glulam frames that caused by uneven settlements of bearings are shown in the article. Three-dimensional finite elements model of the building using LIRA-SAPR 2013 was developed for research. Settlements were determined by the stratified method and by calculations of the system “substructures – foundations – constructions” using physically non-linear soil massive

  12. Remedial investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1992-12-01

    The enactment of the Resource Conservation and Recovery Act (RCRA) in 1976 and the Hazardous and Solid Waste Amendments (HSWA) to RCRA in 1984 created management requirements for hazardous waste fadities. The facilities within the Oak Ridge Reservation (ORR) were in the process of meeting the RCRA requirements when ORR was placed on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCIA) National Priorities List (NPL) on November 21, 1989. Under RCRA, the actions typically follow the RCRA Facility Assessment (RIFA)/RCRA Facility Investigation (RFI)/Coffective Measures Study (CMS)/Corrective Measures Implementation process. Under CERCLA, the actions follow the Pre at sign ary Assessment/Site Investigation (PA/Sl) Remedial Investigation Feasibility Study (RI/FS)/Remedial Design/Remedial Action process. The development of this document will incorporate requirements under both RCRA and CERCIA into an RI Work Plan for the lint phase of characterization of Bear Creek Valley (BCV) Operable Unit (OU) 4

  13. Resistance exercise attenuates skeletal muscle oxidative stress, systemic pro-inflammatory state, and cachexia in Walker-256 tumor-bearing rats.

    Science.gov (United States)

    Padilha, Camila Souza; Borges, Fernando Henrique; Costa Mendes da Silva, Lilian Eslaine; Frajacomo, Fernando Tadeu Trevisan; Jordao, Alceu Afonso; Duarte, José Alberto; Cecchini, Rubens; Guarnier, Flávia Alessandra; Deminice, Rafael

    2017-09-01

    The aim of this study was to investigate the effects of resistance exercise training (RET) on oxidative stress, systemic inflammatory markers, and muscle wasting in Walker-256 tumor-bearing rats. Male (Wistar) rats were divided into 4 groups: sedentary controls (n = 9), tumor-bearing (n = 9), exercised (n = 9), and tumor-bearing exercised (n = 10). Exercised and tumor-bearing exercised rats were exposed to resistance exercise of climbing a ladder apparatus with weights tied to their tails for 6 weeks. The physical activity of control and tumor-bearing rats was confined to the space of the cage. After this period, tumor-bearing and tumor-bearing exercised animals were inoculated subcutaneously with Walker-256 tumor cells (11.0 × 10 7 cells in 0.5 mL of phosphate-buffered saline) while control and exercised rats were injected with vehicle. Following inoculation, rats maintained resistance exercise training (exercised and tumor-bearing exercised) or sedentary behavior (control and tumor-bearing) for 12 more days, after which they were euthanized. Results showed muscle wasting in the tumor-bearing group, with body weight loss, increased systemic leukocytes, and inflammatory interleukins as well as muscular oxidative stress and reduced mTOR signaling. In contrast, RET in the tumor-bearing exercised group was able to mitigate the reduced body weight and muscle wasting with the attenuation of muscle oxidative stress and systemic inflammatory markers. RET also prevented loss of muscle strength associated with tumor development. RET, however, did not prevent the muscle proteolysis signaling via FBXO32 gene messenger RNA expression in the tumor-bearing group. In conclusion, RET performed prior tumor implantation prevents cachexia development by attenuating tumor-induced systemic pro-inflammatory condition with muscle oxidative stress and muscle damage.

  14. Spatial analysis of factors influencing long-term stress in the grizzly bear (Ursus arctos population of Alberta, Canada.

    Directory of Open Access Journals (Sweden)

    Mathieu L Bourbonnais

    Full Text Available Non-invasive measures for assessing long-term stress in free ranging mammals are an increasingly important approach for understanding physiological responses to landscape conditions. Using a spatially and temporally expansive dataset of hair cortisol concentrations (HCC generated from a threatened grizzly bear (Ursus arctos population in Alberta, Canada, we quantified how variables representing habitat conditions and anthropogenic disturbance impact long-term stress in grizzly bears. We characterized spatial variability in male and female HCC point data using kernel density estimation and quantified variable influence on spatial patterns of male and female HCC stress surfaces using random forests. Separate models were developed for regions inside and outside of parks and protected areas to account for substantial differences in anthropogenic activity and disturbance within the study area. Variance explained in the random forest models ranged from 55.34% to 74.96% for males and 58.15% to 68.46% for females. Predicted HCC levels were higher for females compared to males. Generally, high spatially continuous female HCC levels were associated with parks and protected areas while low-to-moderate levels were associated with increased anthropogenic disturbance. In contrast, male HCC levels were low in parks and protected areas and low-to-moderate in areas with increased anthropogenic disturbance. Spatial variability in gender-specific HCC levels reveal that the type and intensity of external stressors are not uniform across the landscape and that male and female grizzly bears may be exposed to, or perceive, potential stressors differently. We suggest observed spatial patterns of long-term stress may be the result of the availability and distribution of foods related to disturbance features, potential sexual segregation in available habitat selection, and may not be influenced by sources of mortality which represent acute traumas. In this wildlife

  15. Spatial analysis of factors influencing long-term stress in the grizzly bear (Ursus arctos) population of Alberta, Canada.

    Science.gov (United States)

    Bourbonnais, Mathieu L; Nelson, Trisalyn A; Cattet, Marc R L; Darimont, Chris T; Stenhouse, Gordon B

    2013-01-01

    Non-invasive measures for assessing long-term stress in free ranging mammals are an increasingly important approach for understanding physiological responses to landscape conditions. Using a spatially and temporally expansive dataset of hair cortisol concentrations (HCC) generated from a threatened grizzly bear (Ursus arctos) population in Alberta, Canada, we quantified how variables representing habitat conditions and anthropogenic disturbance impact long-term stress in grizzly bears. We characterized spatial variability in male and female HCC point data using kernel density estimation and quantified variable influence on spatial patterns of male and female HCC stress surfaces using random forests. Separate models were developed for regions inside and outside of parks and protected areas to account for substantial differences in anthropogenic activity and disturbance within the study area. Variance explained in the random forest models ranged from 55.34% to 74.96% for males and 58.15% to 68.46% for females. Predicted HCC levels were higher for females compared to males. Generally, high spatially continuous female HCC levels were associated with parks and protected areas while low-to-moderate levels were associated with increased anthropogenic disturbance. In contrast, male HCC levels were low in parks and protected areas and low-to-moderate in areas with increased anthropogenic disturbance. Spatial variability in gender-specific HCC levels reveal that the type and intensity of external stressors are not uniform across the landscape and that male and female grizzly bears may be exposed to, or perceive, potential stressors differently. We suggest observed spatial patterns of long-term stress may be the result of the availability and distribution of foods related to disturbance features, potential sexual segregation in available habitat selection, and may not be influenced by sources of mortality which represent acute traumas. In this wildlife system and others

  16. American Black Bears as Hosts of Blacklegged Ticks (Acari: Ixodidae) in the Northeastern United States.

    Science.gov (United States)

    Zolnik, Christine P; Makkay, Amanda M; Falco, Richard C; Daniels, Thomas J

    2015-09-01

    Ticks and whole blood were collected from American black bears (Ursus americanus Pallas) between October 2011 and October 2012 across four counties in northwestern New Jersey, an area where blacklegged ticks (Ixodes scapularis Say) and their associated tick-borne pathogens are prevalent. Adult American dog ticks (Dermacentor variabilis Say) were the most frequently collected tick species in late spring, whereas adult and nymphal blacklegged ticks were found in both the late spring and fall months. Additionally, for blacklegged ticks, we determined the quality of bloodmeals that females acquired from black bears compared with bloodmeals from white-tailed deer (Odocoileus virginianus Zimmerman), the most important host for the adult stage of this tick species. Measures of fecundity after feeding on each host species were not significantly different, suggesting that the bloodmeal a female blacklegged tick acquires from a black bear is of similar quality to that obtained from a white-tailed deer. These results establish the American black bear as both a host and quality bloodmeal source to I. scapularis. Thus, black bears may help support blacklegged tick populations in areas where they are both present. In addition, samples of black bear blood were tested for DNA presence of three tick-borne pathogens. Anaplasma phagocytophilum Foggie and Babesia microti Franca were found in 9.2 and 32.3% of blood samples, respectively. All blood samples were quantitative polymerase chain reaction-negative for Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt, & Brenner. Although circulating pathogens were found in blood, the status of black bears as reservoirs for these pathogens remains unknown. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. On machine surface to the unit event causing residual stress

    International Nuclear Information System (INIS)

    Arunachalama, R.M.; Mannanb, M.A.; Spowageca, A.

    2005-01-01

    Integrity and reduce overall costs. Within the framework of surface integrity investigations, special emphasis is given to the measurement of residual stresses because they contribute directly to premature failure of components. Since the highest residual stresses are to be found in surface layers, these deserve special attention when dealing with dynamically, heavily loaded machine parts such as gas turbine components used in aero engines. Of the many techniques available for the measurement of residual stresses, the most highly developed and widely used non-destructive method is based on X-ray diffraction (XRD). However, it is not possible to use this technique for inspection of all the components, since it is time consuming, complicated as well as expensive. In this paper, a method is being proposed that augments the XRD method but at the same time capable of inspecting all the components. A non-destructive, visual inspection technique has been developed that can correlate the characteristic features on the surface to the unit event causing the residual stress and the type of residual stress generated on the machined surface. Pictures of the machined surfaces have been taken using a digital video microscope at a magnification of 500 and the surface feature correlated to the unit event causing the residual stress. Sharp and well defined long grooves indicate that the plastic deformation is dominated by a mechanical unit event while appearance of streaks and small areas of smeared material indicate that the plastic deformation is dominated by a thermal unit event. These trends have been confirmed by measuring the residual stresses using XRD. The proposed technique is an attempt at establishing a simple methodology that would be useful to industries manufacturing aerospace and other components that require good surface integrity. (Author)

  18. Guideline for stress ulcer prophylaxis in the intensive care unit

    DEFF Research Database (Denmark)

    Madsen, Kristian Rørbaek; Lorentzen, Kristian; Clausen, Niels

    2014-01-01

    Stress ulcer prophylaxis (SUP) is commonly used in the intensive care unit (ICU), and is recommended in the Surviving Sepsis Campaign guidelines 2012. The present guideline from the Danish Society of Intensive Care Medicine and the Danish Society of Anesthesiology and Intensive Care Medicine sums...

  19. Specifications for Supplementary Classroom Units, Stressed Skin Panel.

    Science.gov (United States)

    Waring, Robert B.; And Others

    Complete outline specifications are given for the construction of supplementary classroom units using stressed skin panels. Sections included are--(1) concrete and related work, (2) masonry, (3) structural and miscellaneous metal, (4) curtain walls and metal windows, (5) carpentry and related work, (6) roofing, sheet metal, and related work, (7)…

  20. Stress-reducing preventive maintenance model for a unit under stressful environment

    International Nuclear Information System (INIS)

    Park, J.H.; Chang, Woojin; Lie, C.H.

    2012-01-01

    We develop a preventive maintenance (PM) model for a unit operated under stressful environment. The PM model in this paper consists of a failure rate model and two cost models to determine the optimal PM scheduling which minimizes a cost rate. The assumption for the proposed model is that stressful environment accelerates the failure of the unit and periodic maintenances reduce stress from outside. The failure rate model handles the maintenance effect of PM using improvement and stress factors. The cost models are categorized into two failure recognition cases: immediate failure recognition and periodic failure detection. The optimal PM scheduling is obtained by considering the trade-off between the related cost and the lifetime of a unit in our model setting. The practical usage of our proposed model is tested through a numerical example.

  1. Post-traumatic stress disorder in intensive care unit patients.

    Science.gov (United States)

    Caiuby, Andrea Vannini Santesso; Andreoli, Paola Bruno de Araújo; Andreoli, Sergio Baxter

    2010-03-01

    Post-traumatic stress disorder has been detected in patients after treatment in intensive care unit. The main goal of this study is to review the psychological aspects and therapeutic interventions on those patients after their treatment on intensive care unit. Thirty eight articles have been included. The prevalence of post-traumatic stress disorder has varied from 17% up to 30% and the incidence from 14% to 24%. The risk factors were: previous anxiety historic, depression or panic, having delusional traumatic memories (derived from psychic formations as dreams and delirium), belief effects, depressive behavior, stressing experiences and mechanical ventilation. High doses of opiates, symptoms caused by sedation or analgesia reduction and the use of lorazepam were related with the increase of delirium and delusional memory. The disorder sintomatology can be reduced with hydrocortisone administration, with daily sedation interruption. No other effectiveness psychological intervention study was found.

  2. Role of multiaxial stress state in the hydrogen-assisted rolling-contact fatigue in bearings for wind turbines

    Directory of Open Access Journals (Sweden)

    J. Toribio

    2015-07-01

    Full Text Available Offshore wind turbines often involve important engineering challenges such as the improvement of hydrogen embrittlement resistance of the turbine bearings. These elements frequently suffer the so-called phenomenon of hydrogen-assisted rolling-contact fatigue (HA-RCF as a consequence of the synergic action of the surrounding harsh environment (the lubricant supplying hydrogen to the material and the cyclic multiaxial stress state caused by in-service mechanical loading. Thus the complex phenomenon could be classified as hydrogen-assisted rolling-contact multiaxial fatigue (HA-RC-MF. This paper analyses, from the mechanical and the chemical points of view, the so-called ball-on-rod test, widely used to evaluate the hydrogen embrittlement susceptibility of turbine bearings. Both the stress-strain states and the steady-state hydrogen concentration distribution are studied, so that a better elucidation can be obtained of the potential fracture places where the hydrogen could be more harmful and, consequently, where the turbine bearings could fail during their life in service.

  3. Development, implementation and operational experience with 900 mm R1T pocket-type bearings at Oskarshamn unit 3 nuclear steam turbine generator

    International Nuclear Information System (INIS)

    Peel, P.; Roos, A.

    2015-01-01

    The Oskarshamn unit 3 nuclear steam turbine generator in Sweden is operated by OKG and, following the extensive PULS upgrade project, delivers an increased rated output of 1450 MW making it the most powerful BWR unit worldwide. Several turbine bearing incidents occurred in 2009 and 2010, which initiated a detailed root cause analysis to determine the reasons and propose appropriate mitigation measures to ensure reliable unit operation. Together with OKG, ALSTOM Power implemented a short-term solution to operate the unit over the winter period of 2010-11. Subsequently, during the annual outage in June 2011, a permanent solution involving a R1T pocket-type bearing design was installed at three shaft-line positions. Since the 1980's, R1T bearings with diameters from 250 to 670 mm have been operating in numerous full-speed (3000/3600 rpm) steam turbine generators. However, this was the first application of a R1T bearing developed at a diameter of 900 mm and for half-speed operation. This paper presents an overview of the bearing development and details the successful operational feedback gathered to date on the three installed bearings. In comparison with the three tilting pad bearing design, which has typically been used on large half-speed ALSTOM Power steam turbine generators to date, it confirms the R1T bearing design as a viable alternative. (authors)

  4. Fathers' Stress in a Neonatal Intensive Care Unit

    DEFF Research Database (Denmark)

    Noergaard, Betty; Ammentorp, Jette; Garne, Ester

    2018-01-01

    BACKGROUND: Healthcare professionals in neonatal intensive care units (NICUs) tend to focus attention on the mothers and the newborn infants. Thus, fathers may find it difficult to establish an optimal father-child relationship and their stress may increase and persist during hospitalization...... and expect fathers to be involved, and support them to establish a father-child relationship, although they might become more stressed. IMPLICATIONS FOR RESEARCH: More adequate outcome measures are needed to determine the effect of interventions on paternal stress.This is an open-access article distributed....... PURPOSE: To investigate the impact of a more father-friendly NICU on paternal stress and their participation in childcare. METHODS: A quasiexperimental design was conducted on Danish-speaking fathers of newborn infants 28 or more weeks' gestational age. The Parental Stressor Scale: Neonatal Intensive Care...

  5. Patient stress in intensive care: comparison between a coronary care unit and a general postoperative unit

    Science.gov (United States)

    Dias, Douglas de Sá; Resende, Mariane Vanessa; Diniz, Gisele do Carmo Leite Machado

    2015-01-01

    Objective To evaluate and compare stressors identified by patients of a coronary intensive care unit with those perceived by patients of a general postoperative intensive care unit. Methods This cross-sectional and descriptive study was conducted in the coronary intensive care and general postoperative intensive care units of a private hospital. In total, 60 patients participated in the study, 30 in each intensive care unit. The stressor scale was used in the intensive care units to identify the stressors. The mean score of each item of the scale was calculated followed by the total stress score. The differences between groups were considered significant when p < 0.05. Results The mean ages of patients were 55.63 ± 13.58 years in the coronary intensive care unit and 53.60 ± 17.47 years in the general postoperative intensive care unit. For patients in the coronary intensive care unit, the main stressors were “being in pain”, “being unable to fulfill family roles” and “being bored”. For patients in the general postoperative intensive care unit, the main stressors were “being in pain”, “being unable to fulfill family roles” and “not being able to communicate”. The mean total stress scores were 104.20 ± 30.95 in the coronary intensive care unit and 116.66 ± 23.72 (p = 0.085) in the general postoperative intensive care unit. When each stressor was compared separately, significant differences were noted only between three items. “Having nurses constantly doing things around your bed” was more stressful to the patients in the general postoperative intensive care unit than to those in the coronary intensive care unit (p = 0.013). Conversely, “hearing unfamiliar sounds and noises” and “hearing people talk about you” were the most stressful items for the patients in the coronary intensive care unit (p = 0.046 and 0.005, respectively). Conclusion The perception of major stressors and the total stress score were similar between patients

  6. An updated stress map of the continental United States reveals heterogeneous intraplate stress

    Science.gov (United States)

    Levandowski, Will; Herrmann, Robert B.; Briggs, Rich; Boyd, Oliver; Gold, Ryan

    2018-06-01

    Knowledge of the state of stress in Earth's crust is key to understanding the forces and processes responsible for earthquakes. Historically, low rates of natural seismicity in the central and eastern United States have complicated efforts to understand intraplate stress, but recent improvements in seismic networks and the spread of human-induced seismicity have greatly improved data coverage. Here, we compile a nationwide stress map based on formal inversions of focal mechanisms that challenges the idea that deformation in continental interiors is driven primarily by broad, uniform stress fields derived from distant plate boundaries. Despite plate-boundary compression, extension dominates roughly half of the continent, and second-order forces related to lithospheric structure appear to control extension directions. We also show that the states of stress in several active eastern United States seismic zones differ significantly from those of surrounding areas and that these anomalies cannot be explained by transient processes, suggesting that earthquakes are focused by persistent, locally derived sources of stress. Such spatially variable intraplate stress appears to justify the current, spatially variable estimates of seismic hazard. Future work to quantify sources of stress, stressing-rate magnitudes and their relationship with strain and earthquake rates could allow prospective mapping of intraplate hazard.

  7. Profiles of Reservoir Properties of Oil-Bearing Plays for Selected Petroleum Provinces in the United States

    Science.gov (United States)

    Freeman, P.A.; Attanasi, E.D.

    2015-11-05

    Profiles of reservoir properties of oil-bearing plays for selected petroleum provinces in the United States were developed to characterize the database to be used for a potential assessment by the U.S. Geological Survey (USGS) of oil that would be technically recoverable by the application of enhanced oil recovery methods using injection of carbon dioxide (CO2-EOR). The USGS assessment methodology may require reservoir-level data for the purposes of screening conventional oil reservoirs and projecting CO2-EOR performance in terms of the incremental recoverable oil. The information used in this report is based on reservoir properties from the “Significant Oil and Gas Fields of the United States Database” prepared by Nehring Associates, Inc. (2012). As described by Nehring Associates, Inc., the database “covers all producing provinces (basins) in the United States except the Appalachian Basin and the Cincinnati Arch.”

  8. Influence of bearing pre-load coefficient on shaft vibration and pad temperature in a hydroturbine generator unit. A case study

    Energy Technology Data Exchange (ETDEWEB)

    Feng Fuzhou; Chu Fulei; Guo Dan; Lu Wenxiu [Tsinghua Univ., Beijing, BJ (China). Dept. of Precision Instruments

    2001-07-01

    From data collected by an online condition monitoring and fault diagnosis system, a higher pad temperature at the upper guide bearing in a pumped storage power generator unit installed in Guangdong province(GPSPS), China, was found. And also a relatively intensive shaft vibration occurred at the lower guide bearing. By calculating the Reynolds equation and viscosity-temperature equation of the lubricant, a curve between the pre-load coefficient and the increment of pad temperature is obtained, which shows that the larger, the pre-load coefficient, the bigger, the increment of pad temperature. For a practical unit in GPSPS, by employing Transfer matrix method and Wilson-{theta} method to analyze shaft vibration at different pre-load coefficients of the whole bearing or ''pad pair'' bearings, the results show that the larger the pre-load coefficient is, the smaller the vibration amplitude is, the shorter the time for vibration to become steady is. And an uneven pre-load coefficient of the ''pad pair'' bearings will cause shaft orbit from a circle to an ellipse whose long axes is at the direction of the ''pad pair'' with the lowest pre-load coefficient. Finally, reasons of higher pad temperature of the upper guide bearing and larger shaft vibration at the lower guide bearing are due to the inconsistent relation of bearing assembling clearance or pre-load coefficient of the upper and lower guide bearing, and also due to the too small, uneven pre-load coefficient of ''pad pair'' bearings. After a scheme for adjusting the bearing clearance is given, data measured show that the analysis and simulation methods are correct and the adjustment scheme to the assembling clearance of the upper and lower guide bearings is feasible and can be used to guide the field maintenance conveniently. (orig.)

  9. 76 FR 798 - Ball Bearings From Japan and the United Kingdom

    Science.gov (United States)

    2011-01-06

    ...The U.S. International Trade Commission (``Commission'') hereby gives notice of its fourth remand proceeding with respect to its affirmative determination in the five-year review of the antidumping duty order on ball bearings from Japan. For further information concerning the conduct of this proceeding and rules of general application, consult the Commission's Rules of Practice and Procedure, part 201, subparts A through E (19 CFR part 201), and part 207, subpart A (19 CFR part 207).

  10. Stress ulcer prophylaxis in the intensive care unit trial

    DEFF Research Database (Denmark)

    Krag, M; Perner, A; Wetterslev, J

    2017-01-01

    BACKGROUND: In this statistical analysis plan, we aim to provide details of the pre-defined statistical analyses of the Stress Ulcer Prophylaxis in the Intensive Care Unit (SUP-ICU) trial. The aim of the SUP-ICU trial is to assess benefits and harms of stress ulcer prophylaxis with a proton pump......-year mortality, and a health economic analysis. Two formal interim analyses will be performed. The statistical analyses will be conducted according to the outlined pre-defined statistical analysis plan. The primary analysis will be a logistic regression analysis adjusted for stratification variables...... comparing the two intervention groups in the intention-to-treat population. In a secondary analysis, we will additionally adjust the primary outcome for potential random differences in baseline characteristics. The conclusion will be based on the intention-to-treat population. CONCLUSION: Stress ulcer...

  11. Oxidative stress and maternal obesity: feto-placental unit interaction.

    Science.gov (United States)

    Malti, N; Merzouk, H; Merzouk, S A; Loukidi, B; Karaouzene, N; Malti, A; Narce, M

    2014-06-01

    To determine oxidative stress markers in maternal obesity during pregnancy and to evaluate feto-placental unit interaction, especially predictors of fetal metabolic alterations. 40 obese pregnant women (prepregnancy BMI > 30 kg/m²) were compared to 50 control pregnant women. Maternal, cord blood and placenta samples were collected at delivery. Biochemical parameters (total cholesterol and triglycerides) and oxidative stress markers (malondialdehyde, carbonyl proteins, superoxide anion expressed as reduced Nitroblue Tetrazolium, nitric oxide expressed as nitrite, reduced glutathione, catalase, superoxide dismutase) were assayed by biochemical methods. Maternal, fetal and placental triglyceride levels were increased in obese group compared to control. Maternal malondialdehyde, carbonyl proteins, nitric oxide and superoxide anion levels were high while reduced glutathione concentrations and superoxide dismutase activity were low in obesity. In the placenta and in newborns of these obese mothers, variations of redox balance were also observed indicating high oxidative stress. Maternal and placental interaction constituted a strong predictor of fetal redox variations in obese pregnancies. Maternal obesity compromised placental metabolism and antioxidant status which strongly impacted fetal redox balance. Oxidative stress may be one of the key downstream mediators that initiate programming of the offspring. Maternal obesity is associated with metabolic alterations and dysregulation of redox balance in the mother-placenta - fetus unit. These perturbations could lead to maternal and fetal complications and should be carefully considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Noise, stress, and annoyance in a pediatric intensive care unit.

    Science.gov (United States)

    Morrison, Wynne E; Haas, Ellen C; Shaffner, Donald H; Garrett, Elizabeth S; Fackler, James C

    2003-01-01

    To measure and describe hospital noise and determine whether noise can be correlated with nursing stress measured by questionnaire, salivary amylase, and heart rate. Cohort observational study. Tertiary care center pediatric intensive care unit. Registered nurses working in the unit. None. Eleven nurse volunteers were recruited. An audiogram, questionnaire data, salivary amylase, and heart rate were collected in a quiet room. Each nurse was observed for a 3-hr period during patient care. Heart rate and sound level were recorded continuously; saliva samples and stress/annoyance ratings were collected every 30 mins. Variables assessed as potential confounders were years of nursing experience, caffeine intake, patients' Pediatric Risk of Mortality Score, shift assignment, and room assignment. Data were analyzed by random effects multiple linear regression using Stata 6.0. The average daytime sound level was 61 dB(A), nighttime 59 dB(A). Higher average sound levels significantly predicted higher heart rates (p =.014). Other significant predictors of tachycardia were higher caffeine intake, less nursing experience, and daytime shift. Ninety percent of the variability in heart rate was explained by the regression equation. Amylase measurements showed a large variability and were not significantly affected by noise levels. Higher average sound levels were also predictive of greater subjective stress (p =.021) and annoyance (p =.016). In this small study, noise was shown to correlate with several measures of stress including tachycardia and annoyance ratings. Further studies of interventions to reduce noise are essential.

  13. Determination of the contact stresses in double-row tapered roller bearings using the finite element method, experimental analysis and analytical models

    Energy Technology Data Exchange (ETDEWEB)

    Lostado, Ruben [University of La Rioja, Logroño (Spain); Martinez, Roberto Fernandez [University of Basque Country UPV/EHU, Bilbao (Spain); MacDonald, Bryan J. [Dublin City University, Dublin (Ireland)

    2015-11-15

    Double-row Tapered roller bearings (TRBs) are mechanical devices that are designed to support high axial, radial and torque loads. This combination of loads produces high contact stresses on the bearing raceways that are difficult to predict and validate experimentally, and can cause defects like pitting and fatigue spalling. In response, theoretical models have been proposed by many researchers to calculate the approximate distribution of contact stresses over the bearing raceways. More recently, numerical methods that are based on the Finite element method (FEM) have been used to obtain the contact stresses, although this method requires that the mesh size first be adjusted. This paper shows a process for adjusting a double-row TRB Finite element (FE) model. It is based on generating successive nonlinear FE submodels to calculate the distribution of contact stresses. A theoretical model and contact pressure sensors were used to adjust and validate the Finite element (FE) model.

  14. Stressful presentations: mild cold stress in laboratory mice influences phenotype of dendritic cells in naïve and tumor-bearing mice.

    Science.gov (United States)

    Kokolus, Kathleen M; Spangler, Haley M; Povinelli, Benjamin J; Farren, Matthew R; Lee, Kelvin P; Repasky, Elizabeth A

    2014-01-01

    The ability of dendritic cells (DCs) to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to model immune responses. The goals of this report are to 1) briefly summarize previous work revealing how DCs respond to various forms of physiological stress and 2) to present new data highlighting the potential for chronic mild cold stress inherent to mice housed at the required standard ambient temperatures to influence baseline DCs properties in naïve and tumor-bearing mice. As recent data from our group shows that CD8(+) T cell function is significantly altered by chronic mild cold stress and since DC function is crucial for CD8(+) T cell activation, we wondered whether housing temperature may also be influencing DC function. Here we report that there are several significant phenotypical and functional differences among DC subsets in naïve and tumor-bearing mice housed at either standard housing temperature or at a thermoneutral ambient temperature, which significantly reduces the extent of cold stress. The new data presented here strongly suggests that, by itself, the housing temperature of mice can affect fundamental properties and functions of DCs. Therefore differences in basal levels of stress due to housing should be taken into consideration when interpreting experiments designed to evaluate the impact of additional variables, including other stressors on DC function.

  15. 78 FR 76104 - Ball Bearings and Parts Thereof From Japan and the United Kingdom: Notice of Reinstatement of...

    Science.gov (United States)

    2013-12-16

    ...On July 15, 2011, pursuant to a decision of the Court of International Trade (CIT) that affirmed the International Trade Commission's (ITC's) negative injury determinations on remand in the second sunset review of the antidumping duty orders on bearings from Japan and the United Kingdom, the Department of Commerce (the Department) revoked the Orders.\\1\\ On May 16, 2013, the United States Court of Appeals for the Federal Circuit (Federal Circuit) reversed the CIT's decision and ordered the CIT to reinstate the ITC's affirmative material injury determinations.\\2\\ Subsequently, on November 18, 2013, the CIT issued final judgment reinstating the ITC's affirmative injury determinations.\\3\\ Therefore, the Department is now reinstating the Orders. Additionally, the Department is resuming the administrative reviews of these orders for the periods May 1, 2009, through April 30, 2010, and May 1, 2010, through April 30, 2011. ---------------------------------------------------------------------------

  16. Population fragmentation and inter-ecosystem movements of grizzly bears in Western Canada and the Northern United States

    Science.gov (United States)

    Proctor, M.F.; Paetkau, David; McLellan, B.N.; Stenhouse, G.B.; Kendall, K.C.; Mace, R.D.; Kasworm, W.F.; Servheen, C.; Lausen, C.L.; Gibeau, M.L.; Wakkinen, W.L.; Haroldson, M.A.; Mowat, G.; Apps, C.D.; Ciarniello, L.M.; Barclay, R.M.R.; Boyce, M.S.; Schwartz, C.C.; Strobeck, C.

    2012-01-01

    Population fragmentation compromises population viability, reduces a species ability to respond to climate change, and ultimately may reduce biodiversity. We studied the current state and potential causes of fragmentation in grizzly bears over approximately 1,000,000 km 2 of western Canada, the northern United States (US), and southeast Alaska. We compiled much of our data from projects undertaken with a variety of research objectives including population estimation and trend, landscape fragmentation, habitat selection, vital rates, and response to human development. Our primary analytical techniques stemmed from genetic analysis of 3,134 bears, supplemented with radiotelemetry data from 792 bears. We used 15 locus microsatellite data coupled withmeasures of genetic distance, isolation-by-distance (IBD) analysis, analysis of covariance (ANCOVA), linear multiple regression, multi-factorial correspondence analysis (to identify population divisions or fractures with no a priori assumption of group membership), and population-assignment methods to detect individual migrants between immediately adjacent areas. These data corroborated observations of inter-area movements from our telemetry database. In northern areas, we found a spatial genetic pattern of IBD, although there was evidence of natural fragmentation from the rugged heavily glaciated coast mountains of British Columbia (BC) and the Yukon. These results contrasted with the spatial pattern of fragmentation in more southern parts of their distribution. Near the Canada-US border area, we found extensive fragmentation that corresponded to settled mountain valleys andmajor highways. Genetic distances across developed valleys were elevated relative to those across undeveloped valleys in central and northern BC. In disturbed areas, most inter-area movements detected were made by male bears, with few female migrants identified. North-south movements within mountain ranges (Mts) and across BC Highway 3 were more common

  17. Measuring environmental stress in East Greenland polar bears, 1892-1927 and 1988-2009: what does hair cortisol tell us?

    Science.gov (United States)

    Bechshøft, T Ø; Rigét, F F; Sonne, C; Letcher, R J; Muir, D C G; Novak, M A; Henchey, E; Meyer, J S; Eulaers, I; Jaspers, V L B; Eens, M; Covaci, A; Dietz, R

    2012-09-15

    Hair sampled from 96 East Greenland polar bears (Ursus maritimus) over the periods 1892-1927 and 1988-2009 was analyzed for cortisol as a proxy to investigate temporal patterns of environmental stress. Cortisol concentration was independent of sex and age, and was found at significantly higher (ppolar bear hair appears to be a relatively poor indicator of the animal's general POP load in adipose tissue. However, further investigations are warranted to explore the reasons for the temporal decrease found in the bears' hair cortisol levels. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. 76 FR 22372 - Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom...

    Science.gov (United States)

    2011-04-21

    ... preliminarily determined that sales have been made below normal value by certain companies subject to these... a bearing does not influence whether the bearing is covered by one of the orders. The orders cover.... The ultimate application of a bearing also does not influence whether the bearing is covered by the...

  19. Posttraumatic stress in intensive care unit survivors - a prospective study

    DEFF Research Database (Denmark)

    Ratzer, Mette; Brink, Ole; Knudsen, Linda

    2014-01-01

    Aims: This study aimed to estimate the prevalence of severe Posttraumatic Stress Disorder (PTSD) symptoms and to identify factors associated with PTSD in survivors of intensive care unit (ICU) treatment following traumatic injury. Methods: Fifty-two patients who were admitted to an ICU through...... the emergency ward following traumatic injury were prospectively followed. Information on injury severity and ICU treatment were obtained through medical records. Demographic information and measures of acute stress symptoms, experienced social support, coping style, sense of coherence (SOC) and locus...... of control were assessed within one-month post-accident (T1). At the six months follow-up (T2), PTSD was assessed with the Harvard Trauma Questionnaire (HTQ). Results: In the six months follow-up, 10 respondents (19.2%) had HTQ total scores reaching a level suggestive of PTSD (N = 52), and 11 respondents (21...

  20. Guideline for stress ulcer prophylaxis in the intensive care unit

    DEFF Research Database (Denmark)

    Madsen, Kristian Rørbaek; Lorentzen, Kristian; Clausen, Niels

    2014-01-01

    Stress ulcer prophylaxis (SUP) is commonly used in the intensive care unit (ICU), and is recommended in the Surviving Sepsis Campaign guidelines 2012. The present guideline from the Danish Society of Intensive Care Medicine and the Danish Society of Anesthesiology and Intensive Care Medicine sums...... critically ill patients in the ICU outside the context of randomized controlled trials (GRADE 1C). No robust evidence supports recommendations for subpopulations in the ICU such as septic, burn, trauma, cardiothoracic or enterally fed patients. However, if SUP is considered clinically indicated in individual...

  1. Grin and bear it: the influence of manipulated facial expression on the stress response.

    Science.gov (United States)

    Kraft, Tara L; Pressman, Sarah D

    2012-01-01

    In the study reported here, we investigated whether covertly manipulating positive facial expressions would influence cardiovascular and affective responses to stress. Participants (N = 170) naive to the purpose of the study completed two different stressful tasks while holding chopsticks in their mouths in a manner that produced a Duchenne smile, a standard smile, or a neutral expression. Awareness was manipulated by explicitly asking half of all participants in the smiling groups to smile (and giving the other half no instructions related to smiling). Findings revealed that all smiling participants, regardless of whether they were aware of smiling, had lower heart rates during stress recovery than the neutral group did, with a slight advantage for those with Duchenne smiles. Participants in the smiling groups who were not explicitly asked to smile reported less of a decrease in positive affect during a stressful task than did the neutral group. These findings show that there are both physiological and psychological benefits from maintaining positive facial expressions during stress.

  2. Residual stresses determination by neutron diffraction in a 100Cr6 chromium steel bearing ring

    Czech Academy of Sciences Publication Activity Database

    Rogante, M.; Martinat, G.; Mikula, Pavol; Vrána, Miroslav

    2013-01-01

    Roč. 51, č. 5 (2013), s. 275-281 ISSN 0023-432X R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : 100Cr6 steel * rings * martensitic hardening * tempering * residual stress es * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.546, year: 2013

  3. Chaos and bifurcation of a flexible rotor supported by porous squeeze couple stress fluid film journal bearings with non-linear suspension

    International Nuclear Information System (INIS)

    Chang-Jian, C.-W.; Chen, C.-K.

    2008-01-01

    This study presents a dynamic analysis of a flexible rotor supported by two porous squeeze couple stress fluid film journal bearings with non-linear suspension. The dynamics of the rotor center and bearing center are studied. The analysis of the rotor-bearing system is investigated under the assumptions of non-Newtonian fluid and a short bearing approximation. The spatial displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The numerical results show that the stability of the system varies with the non-dimensional speed ratios, the non-dimensional parameter l* and the permeability. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided

  4. 76 FR 41761 - Ball Bearings and Parts Thereof From Japan and the United Kingdom: Revocation of Antidumping Duty...

    Science.gov (United States)

    2011-07-15

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-588-804, A-412-801] Ball Bearings and... Commerce (the Department) is revoking the antidumping duty orders on ball bearings and parts thereof from...: Background On May 15, 1989, the Department published the antidumping duty orders on ball bearings and parts...

  5. Evaluation of the increased load bearing capacity of steel beams strengthened with pre-stressed FRP laminates

    Directory of Open Access Journals (Sweden)

    S. Bennati

    2016-10-01

    Full Text Available We analyse the problem of a simply supported steel beam subjected to uniformly distributed load, strengthened with a pre-stressed fibre-reinforced polymer (FRP laminate. We assume that the laminate is first put into tension, then bonded to the beam bottom surface, and finally fixed at both its ends by suitable connections. The beam and laminate are modelled according to classical beam theory. The adhesive is modelled as a cohesive interface with a piecewise linear constitutive law defined over three intervals (elastic response, softening response, debonding. The model is described by a set of differential equations with suitable boundary conditions. An analytical solution to the problem is determined, including explicit expressions for the internal forces and interfacial stresses. As an application, we consider the standard IPE series for the steel beam and the Sika® CarboDur® system for the adhesive and laminate. For each considered cross section, we first carry out a preliminary design of the unstrengthened steel beam. Then, we imagine to apply the FRP strengthening and calculate the loads corresponding to the elastic limit states in the steel beam, adhesive, and laminate. Lastly, we take into account the ultimate limit state corresponding to the plasticisation of the mid-span steel cross section and evaluate the increased load bearing capacity of the strengthened beam

  6. Stress ulcer prophylaxis in the intensive care unit

    DEFF Research Database (Denmark)

    Krag, M; Perner, A; Wetterslev, J

    2015-01-01

    BACKGROUND: Stress ulcer prophylaxis (SUP) may decrease the incidence of gastrointestinal bleeding in patients in the intensive care unit (ICU), but the risk of infection may be increased. In this study, we aimed to describe SUP practices in adult ICUs. We hypothesised that patient selection...... for SUP varies both within and between countries. METHODS: Adult ICUs were invited to participate in the survey. We registered country, type of hospital, type and size of ICU, preferred SUP agent, presence of local guideline, reported indications for SUP, criteria for discontinuing SUP, and concerns about...... adverse effects. Fisher's exact test was used to assess differences between groups. RESULTS: Ninety-seven adult ICUs in 11 countries participated (eight European). All but one ICU used SUP, and 64% (62/97) reported having a guideline for the use of SUP. Proton pump inhibitors were the most common SUP...

  7. Stress ulcer prophylaxis in the intensive care unit

    DEFF Research Database (Denmark)

    Krag, Morten Brøgger; Perner, A; Wetterslev, J

    2013-01-01

    Stress ulcer prophylaxis (SUP) is regarded as standard of care in the intensive care unit (ICU). However, recent randomized, clinical trials (RCTs) and meta-analyses have questioned the rationale and level of evidence for this recommendation. The aim of the present systematic review was to evaluate...... incidence of gastrointestinal (GI) bleeding varies considerably. Data on the incidence and severity of GI bleeding in general ICUs in the developed world as of today are lacking. The best intervention for SUP is yet to be settled by balancing efficacy and harm. In essence, it is unresolved if intensive care...... patients benefit overall from SUP. The following clinically research questions are unanswered: (1) What is the incidence of GI bleeding, and which interventions are used for SUP in general ICUs today?; (2) Which criteria are used to prescribe SUP?; (3) What is the best SUP intervention?; (4) Do intensive...

  8. A comparison of folate status in women of child-bearing age in Korea and in the United States

    Directory of Open Access Journals (Sweden)

    Hyun T

    2012-07-01

    Full Text Available Taisun Hyun,1 Suguna Badiga,2 Han Byul Jang,1 Young-Hee Han,1 Chandrika J Piyathilake21Department of Food and Nutrition, Chungbuk National University, Cheongju, Korea; 2Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USABackground: Even though several studies have demonstrated that periconceptional supplementation with folic acid (FA reduces the occurrence of neural tube defects, FA fortification has been a topic of intense debate due to the possible adverse effects of higher folate status on several health conditions. Several countries, including Korea, have been indecisive as to whether fortification is warranted or not. It is therefore helpful for these countries to compare folate concentrations in their populations with populations exposed to mandatory FA fortification.Purpose: To evaluate the differences in the distribution of circulating concentrations of folate in Korea and the United States (US at different time points.Methods: The Korean study populations consisted of women of child-bearing age recruited in 1999 and in 2009. The US study populations consisted of women of child-bearing age recruited in the post FA fortification era (2005 and 2009. Plasma and red blood cell (RBC folate concentrations were measured using the Lactobacillus casei microbiological assay.Results: The percentage of US women with neural tube defect-protective levels of RBC folate was significantly higher compared to Korean women in 1999 and 2009. However, in 2009, when FA supplements became readily available for Koreans, 50% of Korean women in the study achieved the neural tube defect-protective level of RBC folate; 11% of them demonstrating supraphysiologic concentrations of plasma folate. Even though FA fortification in the US resulted in more than 80of women achieving >400 ng/mL of RBC folate by 2009, nearly 50% also demonstrated having supraphysiologic concentrations of plasma folate, which prompted some researchers to

  9. Geochemical mass balance for sulfur- and nitrogen-bearing acid components: Eastern United States

    International Nuclear Information System (INIS)

    Bischoff, W.D.; Mackenzie, F.T.; Paterson, V.L.

    1984-01-01

    The impact on a geographical region of SO 2 and nitrogen oxides (NO /SUB x/ ) emissions to the atmosphere because of man's activities (e.g., burning of fossil fuels and smelting of sulfide ores) usually has not been considered in terms of a regional geochemical mass balance model. Mass balance models, however, have been employed extensively on a global scale. The models evaluate reservoir sizes, processes and fluxes associated with the transfer of a substance within a system of interest. The models may be steady- or transient-state, and include assessment of historical (geologic), present and future data and processes. In this chapter a geochemical mass balance model is applied to constituents of acid precipitation (H + , NO - 3 and SO 2- ) to evaluate the impact of acid precipitation on the eastern United States

  10. Total Hip Arthroplasty Bearing Surface Trends in the United States From 2007 to 2014: The Rise of Ceramic on Polyethylene.

    Science.gov (United States)

    Heckmann, Nathanael D; Sivasundaram, Lakshmanan; Stefl, Michael D; Kang, Hyunwoo Paco; Basler, Eric T; Lieberman, Jay R

    2018-06-01

    Wear of the bearing surface is a critical element in determining the longevity of a total hip arthroplasty (THA). Over the past decade, concerns related to modern metal-on-metal (MoM) bearings and corrosion at the femoral head-neck interface have influenced surgeon selection of bearing surfaces. The purpose of this study is to analyze trends in THA bearing surface selection from 2007 through 2014 using a large national database. The Nationwide Inpatient Sample database was used to extract bearing surface data from patients who underwent a primary THA between 2007 and 2014. Patients were grouped by bearing surface type: metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), MoM, and ceramic-on-ceramic (CoC) bearings. Descriptive statistics were employed to describe trends. Univariate and multivariate analyses were performed to identify differences between bearing surface groups. During the study period, 2,460,640 THA discharges were identified, of which 1,059,825 (43.1%) had bearing surface data. A total of 496,713 (46.9%) MoP, 307,907 (29.1%) CoP, 210,381 (19.9%) MoM, and 44,823 (4.2%) CoC cases were identified. MoM utilization peaked in 2008 representing 40.1% of THAs implanted that year and steadily declined to 4.0% in 2014. From 2007 to 2014, the use of CoP bearing surfaces increased from 11.1% of cases in 2007 to 50.8% of cases in 2014. In 2014, CoP utilization surpassed MoP which represented 42.1% of bearing surfaces that year. During the study period, MoM bearing surfaces decreased precipitously, while CoP surpassed MoP as the most popular bearing surface used in a THA. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Stress among Accounting Educators in the United States.

    Science.gov (United States)

    Seiler, Robert E.; Pearson, Della A.

    1984-01-01

    Stress among accounting educators was investigated and relationships between stress levels and work satisfaction levels, personality traits, and stress-coping techniques were examined. The most important personality charcteristics of higher stress individuals were impatience, assertiveness, workaholism, and idealism. (Author/MLW)

  12. Crystal structures of titanium–aluminium and –gallium complexes bearing two μ2-CH3 units

    Directory of Open Access Journals (Sweden)

    Tim Oswald

    2017-05-01

    Full Text Available The isotypic crystal structures of two titanocene complexes containing an EMe3 unit (E = Al, Ga; Me = methyl with two μ2-coordinating methyl groups, namely [μ-1(η5-(adamantan-1-yl-2κC1cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5-pentamethylcyclopentadienyl]aluminiumtitanium(III, [AlTi(CH33(C10H15(C15H18], and [μ-1(η5-(adamantan-1-yl-2κC1cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5-pentamethylcyclopentadienyl]galliumtitanium(III, [GaTi(CH33(C10H15(C15H18], are reported. Reacting a dinuclear nitrogen-bridged low-valent titanium(III complex with the Lewis acids AlMe3 or GaMe3 results in the loss of molecular dinitrogen and the formation of two monomeric titanocene(III fragments bearing two μ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a new E—C bond involving the pentafulvene ligand while the bridging and terminal methyl groups remain intact.

  13. Determinants of stress for staff in a neonatal intensive care unit.

    OpenAIRE

    Astbury, J; Yu, V Y

    1982-01-01

    Components of stress for 22 paediatric consultants and 29 nursing sisters working in neonatal intensive care units were studied. Ten situations were rated for their intensity of stress and their frequency of occurrence. For intensity of stress, significantly more paediatric consultants rated the competing demands of personal life versus work as highly stressful, than did nursing sisters. For frequency of stress, significantly more paediatric consultants rated 4 situations as frequently occurr...

  14. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  15. APPLICATION OF COMPUTER SIMULATION IN THE EVALUATION OF THE STRESS-STRAIN STATE OF LOAD-BEARING STRUCTURES OF BUILDINGS MASONRY

    Directory of Open Access Journals (Sweden)

    Anatoliy I. Bedov

    2017-03-01

    Full Text Available The results of studies on the analysis of the stress-strain state of the structures of bearing walls of high-hollow pottery. The way of modeling masonry finite element method. The experimental study of masonry structures produced in the Republic of Bashkortostan high-hollow pottery, set the nature of their work load, the mechanism of destruction. The results of the comparative evaluation of the calculations in the software package and the traditional “manual” calculation.

  16. Mode selectivity in the intramolecular cyclization of ketenimines bearing N-acylimino units: a computational and experimental study.

    Science.gov (United States)

    Alajarín, Mateo; Sánchez-Andrada, Pilar; Vidal, Angel; Tovar, Fulgencio

    2005-02-18

    [reaction: see text] The mode selectivity in the intramolecular cyclization of a particular class of ketenimines bearing N-acylimino units has been studied by ab initio and DFT calculations. In the model compounds the carbonyl carbon atom and the keteniminic nitrogen atom are linked either by a vinylic or an o-phenylene tether. Two cyclization modes have been analyzed: the [2+2] cycloaddition furnishing compounds with an azeto[2,1-b]pyrimidinone moiety and a 6pi-electrocyclic ring closure leading to compounds enclosing a 1,3-oxazine ring. The [2+2] cycloaddition reaction takes place via a two-step process with formation of a zwitterionic intermediate, which has been characterized as a cross-conjugated mesomeric betaine. The 6pi-electrocyclic ring closure occurs via a transition state whose pseudopericyclic character has been established on the basis of its magnetic properties, geometry, and NBO analysis. The 6pi-electrocyclic ring closure is energetically favored over the [2+2] cycloaddition, although the [2+2] cycloadducts are the thermodynamically controlled products. A quantitative kinetic analysis predicts that 1,3-oxazines would be the kinetically controlled products, but they should transform rapidly and totally into the [2+2] cycloadducts at room temperature. In the experimental study, a number of N-acylimino-ketenimines, in which both reactive functions are supported on an o-phenylene scaffold, have been successfully synthesized in three steps starting from 2-azidobenzoyl chloride. These compounds rapidly convert into azeto[2,1-b]quinazolin-8-ones in moderate to good yields as a result of a formal [2+2] cycloaddition.

  17. Lessons that Bear Repeating and Repeating that Bears Lessons: An Interdisciplinary Unit on Principles of Minimalism in Modern Music, Art, and Poetry (Grades 4-8)

    Science.gov (United States)

    Smigel, Eric; McDonald, Nan L.

    2012-01-01

    This theory-to-practice article focuses on interdisciplinary classroom activities based on principles of minimalism in modern music, art, and poetry. A lesson sequence was designed for an inner-city Grades 4 and 5 general classroom of English language learners, where the unit was taught, assessed, and documented by the authors. Included in the…

  18. Polar bear attacks on humans: Implications of a changing climate

    Science.gov (United States)

    Wilder, James; Vongraven, Dag; Atwood, Todd C.; Hansen, Bob; Jessen, Amalie; Kochnev, Anatoly A.; York, Geoff; Vallender, Rachel; Hedman, Daryll; Gibbons, Melissa

    2017-01-01

    Understanding causes of polar bear (Ursus maritimus) attacks on humans is critical to ensuring both human safety and polar bear conservation. Although considerable attention has been focused on understanding black (U. americanus) and grizzly (U. arctos) bear conflicts with humans, there have been few attempts to systematically collect, analyze, and interpret available information on human-polar bear conflicts across their range. To help fill this knowledge gap, a database was developed (Polar Bear-Human Information Management System [PBHIMS]) to facilitate the range-wide collection and analysis of human-polar bear conflict data. We populated the PBHIMS with data collected throughout the polar bear range, analyzed polar bear attacks on people, and found that reported attacks have been extremely rare. From 1870–2014, we documented 73 attacks by wild polar bears, distributed among the 5 polar bear Range States (Canada, Greenland, Norway, Russia, and United States), which resulted in 20 human fatalities and 63 human injuries. We found that nutritionally stressed adult male polar bears were the most likely to pose threats to human safety. Attacks by adult females were rare, and most were attributed to defense of cubs. We judged that bears acted as a predator in most attacks, and that nearly all attacks involved ≤2 people. Increased concern for both human and bear safety is warranted in light of predictions of increased numbers of nutritionally stressed bears spending longer amounts of time on land near people because of the loss of their sea ice habitat. Improved conflict investigation is needed to collect accurate and relevant data and communicate accurate bear safety messages and mitigation strategies to the public. With better information, people can take proactive measures in polar bear habitat to ensure their safety and prevent conflicts with polar bears. This work represents an important first step towards improving our understanding of factors influencing

  19. Remedial Investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODS) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regime`s, which are labeled as integrator OUs. This Remedial Investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the Feasibility Study to evaluate all probable or likely alternatives.

  20. Remedial investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODs) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regimes, which are labeled as integrator OUs. This remedial investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the feasibility study to evaluate all probable or likely alternatives.

  1. Remedial investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1993-07-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODs) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regimes, which are labeled as integrator OUs. This remedial investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the feasibility study to evaluate all probable or likely alternatives

  2. Remedial Investigation work plan for Bear Creek Valley Operable Unit 4 (shallow groundwater in Bear Creek Valley) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1993-09-01

    To effectively evaluate the cumulative impact of releases from multiple sources of contamination, a structured approach has been adopted for Oak Ridge Reservation (ORR) based on studies of the groundwater and surface water separate from studies of the sources. Based on the realization of the complexity of the hydrogeologic regime of the ORR, together with the fact that there are numerous sources contributing to groundwater contamination within a geographical area, it was agreed that more timely investigations, at perhaps less cost, could be achieved by separating the sources of contamination from the groundwater and surface water for investigation and remediation. The result will be more immediate attention [Records of Decision (RODS) for interim measures or removal actions] for the source Operable Units (OUs) while longer-term remediation investigations continue for the hydrogeologic regime's, which are labeled as integrator OUs. This Remedial Investigation work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. Taking advantage of the historical data base and ongoing monitoring activities and applying the observational approach to focus data gathering activities will allow the Feasibility Study to evaluate all probable or likely alternatives

  3. Groundwater-quality data in the Bear Valley and Selected Hard Rock Areas study unit, 2010: Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Belitz, Kenneth

    2013-01-01

    Groundwater quality in the 112-square-mile Bear Valley and Selected Hard Rock Areas (BEAR) study unit was investigated by the U.S. Geological Survey (USGS) from April to August 2010, as part of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program’s Priority Basin Project (PBP). The GAMA-PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001 and is being conducted in collaboration with the SWRCB and Lawrence Livermore National Laboratory (LLNL). The BEAR study unit was the thirty-first study unit to be sampled as part of the GAMA-PBP. The GAMA Bear Valley and Selected Hard Rock Areas study was designed to provide a spatially unbiased assessment of untreated-groundwater quality in the primary aquifer system and to facilitate statistically consistent comparisons of untreated groundwater quality throughout California. The primary aquifer system is defined as the zones corresponding to the perforation intervals of wells listed in the California Department of Public Health (CDPH) database for the BEAR study unit. Groundwater quality in the primary aquifer system may differ from the quality in the shallow or deep water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. In the BEAR study unit, groundwater samples were collected from two study areas (Bear Valley and Selected Hard Rock Areas) in San Bernardino County. Of the 38 sampling sites, 27 were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the primary aquifer system in the study unit (grid sites), and the remaining 11 sites were selected to aid in the understanding of the potential groundwater-quality issues associated with septic tank use and with ski areas in the study unit (understanding sites). The groundwater samples were analyzed for organic constituents (volatile organic compounds [VOCs], pesticides and

  4. Neonatal Intensive Care Unit Nurses Working in an Open Ward: Stress and Work Satisfaction.

    Science.gov (United States)

    Lavoie-Tremblay, Mélanie; Feeley, Nancy; Lavigne, Geneviève L; Genest, Christine; Robins, Stéphanie; Fréchette, Julie

    2016-01-01

    There is some research on the impact of open-ward unit design on the health of babies and the stress experienced by parents and nurses in neonatal intensive care units. However, few studies have explored the factors associated with nurse stress and work satisfaction among nurses practicing in open-ward neonatal intensive care units. The purpose of this study was to examine what factors are associated with nurse stress and work satisfaction among nurses practicing in an open-ward neonatal intensive care unit. A cross-sectional correlational design was used in this study. Participants were nurses employed in a 34-bed open-ward neonatal intensive care unit in a major university-affiliated hospital in Montréal, Quebec, Canada. A total of 94 nurses were eligible, and 86 completed questionnaires (91% response rate). Descriptive statistics were computed to describe the participants' characteristics. To identify factors associated with nurse stress and work satisfaction, correlational analysis and multiple regression analyses were performed with the Nurse Stress Scale and the Global Work Satisfaction scores as the dependent variables. Different factors predict neonatal intensive care unit nurses' stress and job satisfaction, including support, family-centered care, performance obstacles, work schedule, education, and employment status. In order to provide neonatal intensive care units nurses with a supportive environment, managers can provide direct social support to nurses and influence the culture around teamwork.

  5. The effect of stress fracture interventions in a single elite infantry training unit (1983-2015).

    Science.gov (United States)

    Milgrom, Charles; Finestone, Aharon S

    2017-10-01

    Stress fractures can be seen as an undesired byproduct of demanding physical training. The threshold value of stress that places an individual bone at high risk for stress fracture has not been identified. In a prospective study of stress fractures in 1983, a 31% incidence was found during demanding Israeli infantry basic training by bone scan criteria. Within a subgroup of these recruits, an elite infantry unit was found to have a 40% incidence. Since then and until 2015, eight additional induction companies of the same elite infantry unit were prospectively monitored for stress fractures during their basic training. In all of the studies, stress fracture surveillance and the examining orthopedist were the same. A retrospective review of all nine studies and of eight training changes was performed to look for a temporal trend in stress fracture incidence and to see if these might be related to training changes. There was a statistically significant trend for lower radiological proven stress fractures (p=0.0001) and radiological proven stress fractures plus clinical stress fractures (p=0.0013), as well as lower stress fracture severity by radiological criteria (p=0.0001) between 1983 and 2015. The only training change that was associated, by multivariate logistic regression, with a decreased incidence of stress fracture was restricting training to the authorized training protocol (odds ratio, 3874; 95% CI, 1.526 to 9.931; p=0.004). Increased recruit weight was found by multivariate analysis to be associated with lower stress fracture incidence (odds ratio 1.034; 95% CI, 1.00 to 1.070; p=0.051). Moving the training to a base with flatter terrain and reducing the formal marching distance by 1/3 was associated with a decrease in high grade stress fractures (odds ratio, 10.03; 95% CI, 3.5 to 28.4; p=0.0001). Neither the combined changes of enforcing a seven hour a night sleep regimen, training in more comfortable boots and adding a physical therapist to the unit nor

  6. Geographic distribution of selected elements in the livers of polar bears from Greenland, Canada and the United States

    International Nuclear Information System (INIS)

    Rush, Scott A.; Borga, Katrine; Dietz, Rune; Born, Erik W.; Sonne, Christian; Evans, Thomas; Muir, Derek C.G.; Letcher, Robert J.; Norstrom, Ross J.; Fisk, Aaron T.

    2008-01-01

    To assess geographic distributions of elements in the Arctic we compared essential and non-essential elements in the livers of polar bears (Ursus maritimus) collected from five regions within Canada in 2002, in Alaska between 1994 and 1999 and from the northwest and east coasts of Greenland between 1988 and 2000. As, Hg, Pb and Se varied with age, and Co and Zn with gender, which limited spatial comparisons across all populations to Cd, which was highest in Greenland bears. Collectively, geographic relationships appeared similar to past studies with little change in concentration over time in Canada and Greenland for most elements; Hg and Se were higher in some Canadian populations in 2002 as compared to 1982 and 1984. Concentrations of most elements in the polar bears did not exceed toxicity thresholds, although Cd and Hg exceeded levels correlated with the formation of hepatic lesions in laboratory animals. - Geographical trends were observed for a number of elements in livers, including mercury, of polar bears collected across Alaska, Canada and Greenland and were similar to those observed in the early 1980s

  7. Stress ulcer prophylaxis in the intensive care unit

    DEFF Research Database (Denmark)

    Krag, Mette; Perner, Anders; Møller, Morten H

    2016-01-01

    PURPOSE OF REVIEW: Stress ulcer prophylaxis (SUP) is considered standard of care in the majority of critically ill patients in the ICU. In this review, we will present the current evidence for the use of SUP in ICU patients, including data on the prevalence of gastrointestinal bleeding and the ba......PURPOSE OF REVIEW: Stress ulcer prophylaxis (SUP) is considered standard of care in the majority of critically ill patients in the ICU. In this review, we will present the current evidence for the use of SUP in ICU patients, including data on the prevalence of gastrointestinal bleeding...

  8. On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

    OpenAIRE

    Burcharth, H. F.; Howell, G.L.; Liu, Z.

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structural integrity. The paper presents a general discussion of the problems related to stress etermination and describes the results and the analyses of model tests with 200 kg and 200 g load-cell instrume...

  9. Evaluation of heat stress in dry cleaner units:A case study in Qom, Iran

    Directory of Open Access Journals (Sweden)

    Javad Malakouti

    2016-04-01

    Full Text Available Background & Aims of the Study: Nowadays, heat stress is one of the most harmful physical agents in workplaces. According to the consequences of heat stress and have no information about it in Qom dry cleaner units, Iran, this study have been designed to evaluate the heat stress among workers of dry cleaner units in Qom province of Iran, in Jul-Aug 2011. Materials & Methods: This cross-sectional study was conducted in 113 units of active dry cleaner units. WBGT (Wet Bulb Globe Temperature index was selected for heat stress evaluation. In order to measure the requisite parameters, WBGT meter made of Casella Company had been used according to ISO 7243. Data had been analyzed according to Occupational Exposure Limits (OELs with SPSS V.16, using analysis of variance, independent T and LSD tests. Results: The average of WBGT index in Qom dry cleaner units of Iran were 28.98±1.64 °C. The average of WBGT index in 66.4% of units was up to 28°C. The average of relative humidity was 42.86%, the average of wet bulb temperature and globe temperature were 25.56°C and 36.72°C, respectively. The findings showed a significant correlation between the average of WBGT index and the standard recommendation level (p<0.0001. In dry cleaner units with less than 10 m2 area, heat stress was higher than other units  significantly (p<0.05. Conclusions: Heat stress in many dry cleaner units in Qom, Iran, was more than recommended OELs. Because of wet bulb and globe temperature in units were high value, the most important measures to heat controls, are technical engineering controls such as  radiation shield, insulation on boilers and modify the cooling systems.

  10. The use of slow strain rate technique for studying stress corrosion cracking of an advanced silver-bearing aluminum-lithium alloy

    International Nuclear Information System (INIS)

    Frefer, Abdulbaset Ali; Raddad, Bashir S.; Abosdell, Alajale M.

    2013-01-01

    In the present study, stress corrosion cracking (SCC) behavior of naturally aged advanced silver-bearing Al-Li alloy in NaCl solution was investigated using slow strain rate test (SSRT) method. The SSRT’s were conducted at different strain rates and applied potentials at room temperature. The results were discussed based on percent reductions in tensile elongation in a SCC-causing environment over those in air tended to express the SCC susceptbility of the alloy under study at T3. The SCC behavior of the alloy was also discussed based on the microstructural and fractographic examinations

  11. Loss of parental role as a cause of stress in the neonatal intensive care unit.

    Science.gov (United States)

    Bouet, Kary M; Claudio, Norma; Ramirez, Verónica; García-Fragoso, Lourdes

    2012-01-01

    Having a baby in the Neonatal Intensive Care Unit (NICU) is a major source of stress for parents. The barriers to parenting and reactions to the environment may negatively influence the parent-infant relationship. To identify NICU-related parental stress and associated factors. Parents (N = 156) of newborns admitted to NICU completed the Parental Stressor Scale. Most of the parents (46%) rated the experience to be extremely stressful. The principal cause of stress was the alteration in parental role and being separated from their baby. Stress was not associated to education, marital status, infants' birth weight, gestational age, congenital anomalies or if the parents expected the baby to be in the NICU. Identification of areas associated to higher levels of stress in parents may help the NICU staff to establish strategies to help parents cope with the stress caused by being unable to start their parenting role immediately after their babies' birth.

  12. Stress drops of induced and tectonic earthquakes in the central United States are indistinguishable.

    Science.gov (United States)

    Huang, Yihe; Ellsworth, William L; Beroza, Gregory C

    2017-08-01

    Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable median stress drop to tectonic earthquakes in the central United States that are dominantly strike-slip but a lower median stress drop than that of tectonic earthquakes in the eastern North America that are dominantly reverse-faulting. This suggests that ground motion prediction equations developed for tectonic earthquakes can be applied to induced earthquakes if the effects of depth and faulting style are properly considered. Our observation leads to the notion that, similar to tectonic earthquakes, induced earthquakes are driven by tectonic stresses.

  13. Status and understanding of groundwater quality in the Bear Valley and Lake Arrowhead Watershed Study Unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Mathany, Timothy; Burton, Carmen

    2017-06-20

    Groundwater quality in the 112-square-mile Bear Valley and Lake Arrowhead Watershed (BEAR) study unit was investigated as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit comprises two study areas (Bear Valley and Lake Arrowhead Watershed) in southern California in San Bernardino County. The GAMA-PBP is conducted by the California State Water Resources Control Board (SWRCB) in cooperation with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory.The GAMA BEAR study was designed to provide a spatially balanced, robust assessment of the quality of untreated (raw) groundwater from the primary aquifer systems in the two study areas of the BEAR study unit. The assessment is based on water-quality collected by the USGS from 38 sites (27 grid and 11 understanding) during 2010 and on water-quality data from the SWRCB-Division of Drinking Water (DDW) database. The primary aquifer system is defined by springs and the perforation intervals of wells listed in the SWRCB-DDW water-quality database for the BEAR study unit.This study included two types of assessments: (1) a status assessment, which characterized the status of the quality of the groundwater resource as of 2010 by using data from samples analyzed for volatile organic compounds, pesticides, and naturally present inorganic constituents, such as major ions and trace elements, and (2) an understanding assessment, which evaluated the natural and human factors potentially affecting the groundwater quality. The assessments were intended to characterize the quality of groundwater resources in the primary aquifer system of the BEAR study unit, not the treated drinking water delivered to consumers. Bear Valley study area and the Lake Arrowhead Watershed study area were also compared statistically on the basis of water-quality results and factors potentially affecting the groundwater quality.Relative concentrations (RCs

  14. Acculturation stress among Maya in the United States.

    Science.gov (United States)

    Millender, Eugenia

    2012-01-01

    Abstract: As health care disparities become more evident in our multicultural nation, culture sensitive health research needs to be a priority in order for good health care to take place. This article will explore the literature related to acculturation stress and mental health disparities among the Mayan population. Literatures of similar but distinct groups are included due to the limited amount of research of the Mayan population. Using Leiniger's Transcultural nursing theory, these findings suggest that nurses have a large gap to fill to address the mental health disparities of specific cultural groups like the indigenous Maya, thereby satisfying their nursing obligations.

  15. Draft postclosure permit application for Bear Creek Hydrogeologic Regime at the Oak Ridge Y-12 Plant Oil Landform Hazardous Waste Disposal Unit

    International Nuclear Information System (INIS)

    1991-08-01

    The Oil Landfarm Hazardous-Waste Disposal Unit (HWDU) is located approximately one and one-half miles west of the Department of Energy's (DOE) Y-12 Plant in Oak Ridge, Tennessee. The Oil Landfarm HWDU consists of three disposal plots and along with the Bear Creek Burial Grounds and the S-3 Site comprise the Bear Creek Valley Waste Disposal Area (BCVWDA). The facility was used for the biological degradation of waste oil and machine coolants via landfarming, a process involving the application of waste oils and coolants to nutrient-adjusted soil during the dry months of the year (April to October). The Oil Landfarm HWDU has been closed as a hazardous-waste disposal unit and therefore will be subject to post-closure care. The closure plan for the Oil Landfarm HWDU is provided in Appendix A.1. A post-closure plan for the Oil Landfarm HWDU is presented in Appendix A.2. The purpose of this plan is to identify and describe the activities that will be performed during the post-closure care period. This plan will be implemented and will continue throughout the post-closure care period

  16. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  17. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

    Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

    2002-05-01

    rains also destroy the denning habitat of ringed seals, the polar bears' primary prey. Declines in the ringed seal population would mean a loss of food for polar bears. A trend toward stronger winds and increasing ice drift observed in some parts of the Arctic over the last five decades will likely increase energy expenditures and stress levels in polar bears that spend most of their lives on drifting sea ice. Polar bears face other limiting factors as well. Historically, the main threat to polar bears has been hunting. Satisfactory monitoring information has been obtained for most polar bear populations in recent years, however there is concern about hunting in areas without formal quota systems, such as Greenland. A range of toxic pollutants, including heavy metals, radioactivity, and persistent organic pollutants (POPs) are found throughout the Arctic. Of greatest concern are the effects of POPs on polar bears, which include a general weakening of the immune system, reduced reproductive success and physical deformities. The expansion of oil development in the Arctic poses additional threats; for example, disturbances to denning females in the Arctic National Wildlife Refuge in Alaska could undermine recruitment of the Beaufort Sea polar bear population. These threats, along with other effects of human activity in the Arctic, combine to pressure polar bears and their habitat. Large carnivores are sensitive indicators of ecosystem health and can be used to define the minimum area necessary to preserve intact ecosystems. WWF has identified the polar bear as a unique symbol of the complexities and interdependencies of the arctic marine ecosystem as it works toward its goal of preserving biodiversity for future generations.

  18. The effect of massage therapy on occupational stress of Intensive Care Unit nurses.

    Science.gov (United States)

    Nazari, Fateme; Mirzamohamadi, Mojtaba; Yousefi, Hojatollah

    2015-01-01

    One of the main causes of stress in the lives of people is their jobs. Occupational stress is causing a wide range of significant issues in health and community services. Nursing is the most stressful profession in the health services. Massage therapy is one way of coping with stress. This study was conducted to determine the effect of massage therapy on stress in nurses. This study was a clinical trial on 66 male and female nurses working in intensive care units (dialysis, ICU, and CCU) of Isfahan University of Medical Sciences, Iran, in 2013. Participants were selected according to the aims and inclusion criteria of the study. Then, they were randomly divided into experimental and control groups. The Occupational Stress Inventory (OSI) (Osipow and Spokane, 1987) was completed by participants of the two groups before, immediately after, and 2 weeks after the intervention. General Swedish massage was performed on participants of the experimental group for 25 min in each session, twice a week for 4 weeks. Data were analyzed by descriptive and inferential statistics [Chi-square, t-test, and repeated measures analysis of variance (ANOVA)] using SPSS software. Results showed that the difference in overall mean occupation stress scores between experimental and control groups 2 weeks after the intervention was significant (P < 0.001). According to the results, it is recommended that massage, as a valuable noninvasive method, be used for nurses in intensive care units to reduce their stress, promote mental health, and prevent the decrease in quality of nursing work life.

  19. On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Howell, G.L.; Liu, Z.

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structu......Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...... and scale effects. Moreover, some results from the Crescent City Prototype Dolosse study are presented and related to results from small-de model tests. A preliminary design diagram for Dolosse ir presented as well....

  20. Stress analysis of jacks, frame and bearing connections, and drill rod for core sampler truck No. 2

    International Nuclear Information System (INIS)

    Ziada, H.H.

    1995-01-01

    This analysis evaluates the structural design adequacy of several components and connections for the rotary mode core sampler truck (RMCST) No. 2. This analysis was requested by the Characterization Equipment Group (WHC 1994a). The components addressed in this report are listed below: front jack assembly and connection to the truck chassis; rear jack assembly and connection to the truck chassis; center outrigger jacks and connection to the truck chassis; lower frame assembly and connection to the truck chassis; bolt connections for bearing plate assembly (for path of maximum load); traverse slide brackets and mounting of the traverse jack cylinders; and drill rod (failure loads)

  1. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  2. Grizzly bear

    Science.gov (United States)

    Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

    2003-01-01

    The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

  3. Pacoma: Performance assessment of the confinement of medium-active and alpha-bearing wastes. Assessment of disposal in a clay formation in the United Kingdom

    International Nuclear Information System (INIS)

    Mobbs, S.F.; Klos, R.A.; Martin, J.S.; Laurens, J.M.; Winters, K.H.

    1991-01-01

    This report describes the PACOMA assessment of the radiological impact of disposal of intermediate level and alpha-bearing wastes in a hypothetical repository situated in the clay formations below the Harwell site in the United Kingdom. The assessment includes: best estimate calculations, uncertainty analyses, sensitivity analyses and model comparisons. Results of the radiological impact calculations are in the form of doses and risks to individuals and time-integrated doses to populations, for a normal evolution scenario and a number of altered evolution scenarios. The calculated risks to individuals are well below the limit recommended by the ICRP, and the calculated collective dose over the first 10,000 years after disposal is zero. Thus the radiological impact of the disposal intermediate level and alpha-bearing wastes in a clay formation is predicted to be small. The uncertainty analyses showed that, for the normal evolution scenario, the range of predicted risks to individuals is very wide. However, these results must be treated with caution because a formal methodology for eliciting judgments about model parameter values was only applied in the case of geosphere data. The sensitivity analyses and model comparisons indicated the need for improved models and data for water and radionuclide movement in the near-surface environment

  4. Influence of intramolecular hydrogen bonds on regioselectivity of glycosylation. Synthesis of lupane-type saponins bearing the OSW-1 saponin disaccharide unit and its isomers.

    Science.gov (United States)

    Kuczynska, Kinga; Cmoch, Piotr; Rárová, Lucie; Oklešťková, Jana; Korda, Anna; Pakulski, Zbigniew; Strnad, Miroslav

    2016-03-24

    A series of lupane-type saponins bearing OSW-1 disaccharide unit as well as its regio- and stereoisomers were prepared and used for the structure-activity relationships (SAR) study. Unexpected preference for 1→4-linked regioisomers and an unusual inversion of the conformation of the sugar rings were noted. Cytotoxic activity of new lupane compounds was evaluated in vitro and revealed that some saponins exhibited an interesting bioactivity profile against human cancer cell lines. Influence of the protecting groups on the cytotoxicity was investigated. These results open the way to the synthesis of various lupane-type triterpene and saponin derivatives as potential anticancer compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Communicating with parents in neonatal intensive care units: The impact on parental stress.

    Science.gov (United States)

    Enke, Christian; Oliva Y Hausmann, Andrés; Miedaner, Felix; Roth, Bernhard; Woopen, Christiane

    2017-04-01

    To analyse stress in parents whose infants with very low birth weight have just concluded high-level care in a Neonatal Intensive Care Unit (NICU). More specifically, we aimed 1) to identify groups of parents in the NICU who are particularly at risk of experiencing stress, and 2) to explore the effects of clinical staffś communication on parental stress. Our multi-center-study evaluated views from 1277 parents about care for 923 infants in 66 German NICUs. Answers were linked with separately evaluated medical outcomes of the infants. Separate generalised mixed models estimated the influence of personal, medical and communication-related characteristics on specific parental stress. Parents of a younger age and those of infants with severe prognoses were more likely to experience stress. While empathetic communication as one aspect of staffś communication was shown as appropriate in reducing parental stress, an initial introduction and the quantity of information were only slightly associated with lower levels of stress. Results provide evidence for the need to involve parents empathetically from the beginning of their child's stay in the NICU. Staff in the NICU should communicate empathetically and help to reduce stress in parents particularly at risk. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Computer finite element analysis of stress derived from particular units of torsionally flexible metal coupling

    Directory of Open Access Journals (Sweden)

    Mariusz KUCZAJ

    2010-01-01

    Full Text Available In this article the results of Finite Element Analysis (FEA results of stresses derived from chosen units of torsionally flexible metal coupling are presented. As model and simulation tool for particular component loads is used the Autodesk Inventor Professional 2009 program.

  7. Predictors of stress among parents in pediatric intensive care unit: a prospective observational study.

    Science.gov (United States)

    Aamir, Mohd; Mittal, Kundan; Kaushik, Jaya Shankar; Kashyap, Haripal; Kaur, Gurpreet

    2014-11-01

    To determine the sociodemographic and clinical factors leading to stress among parents whose children are admitted in pediatric intensive care unit (PICU). A prospective observational study was conducted in PICU of a tertiary care hospital of north India. Parents of children admitted to PICU for at least 48 h duration were eligible for participation. At the end of 48 h, parental stress was assessed using parental stress scale (PSS:PICU) questionnaire which was administered to the parents. Baseline demographic and clinical parameters of children admitted to PICU were recorded. The parental stress was compared with demographic and clinical characteristics of children using appropriate statistical methods. A total of 49 parents were finally eligible for participation. Mean (SD) parental stress scores was highest in domains of procedures [1.52 (0.66)] and behavior and emotional [1.32 (0.42)] subscales. Mean (SD) total parental stress score among intubated children [1.31 (0.25)] was significantly more than among non intubated children [0.97 (0.26)] (p parental stress score were comparable in terms of gender (p = 0.15) and socioeconomic status (p = 0.32). On subscale analysis, it was found that professional communication is a significant stressor in age groups 0-12 mo [0.61(0.41)] (p = 0.02). It was observed that parents of intubated children were significantly stressed by the physical appearance of their children (p parental role (p = 0.002). Total parental stress score had a positive correlation with PRISM score (r = 0.308). Indian parents are stressed maximally with environment of PICU. Factor leading to parental stress was intubation status of the child and was not affected by gender or socio demographic profile of the parents.

  8. [Stress in parents of hospitalized newborns in a neonatal intensive care unit].

    Science.gov (United States)

    Palma I, Elisa; Von Wussow K, Fernanda; Morales B, Ignacia; Cifuentes R, Javier; Ambiado T, Sergio

    2017-06-01

    The birth of a child that requires hospitalization in a Neonatal Intensive Care Unit (NICU) can be very stressful for parents. To determine the stress level of parents of newborns (NB) hospitalized in a level III NICU in Santiago, and its association with clinical and sociodemographic variables. Descriptive cross-sectional study. 373 admissions were evaluated. The sampling was non-probabilistic and included parents of RN admitted to the UPCN between 7 and 21 days of hospitalization. Only parents which have visited the RN at least three times were included. i) Questionnaire to obtain data which could not be obtained from the medical record; ii) Parental Stress Scale: Neonatal Intensive Care Unit (PSS:NICU) which measures the perception of parents about stressors from the physical and psychological environment of the UPCN. 100 parents of 59 hospitalized NB participated in the study. The average parental stress was 2.87±0.69. The subscale scores got higher was “Relationship with the baby and parental role”. Complications in pregnancy, prenatal diagnosis or prenatal hospitalization, did not affect the stress level or the presence of prematurity, respiratory diseases, congenital malformations, genopathies or requirement of mechanical ventilation. Stress levels presented in parents are unrelated to gender and to the studied clinical variables.

  9. Tektite-bearing, deep-water clastic unit at the Cretaceous-Tertiary boundary in northeastern Mexico

    Science.gov (United States)

    Smit, J.; Montanari, A.; Swinburne, N. H.; Alvarez, W.; Hildebrand, A. R.; Margolis, S. V.; Claeys, P.; Lowrie, W.; Asaro, F.

    1992-01-01

    The hypothesis of Cretaceous-Tertiary (K-T) boundary impact on Yucatan, Mexico, predicts that nearby sites should show evidence of proximal impact ejecta and disturbance by giant waves. An outcrop along the Arroyo el Mimbral in northeastern Mexico contains a layered clastic unit up to 3 m thick that interrupts a biostratigraphically complete pelagic-marl sequence deposited at more than 400 m water depth. The marls were found to be unsuitable for determining magnetostratigraphy, but foraminiferal biostratigraphy places the clastic unit precisely at the K-T boundary. We interpret this clastic unit as the deposit of a megawave or tsunami produced by an extraterrestrial impact. The clastic unit comprises three main subunits. (1) The basal "spherule bed" contains glass in the form of tektites and microtektites, glass spherules replaced by chlorite-smectite and calcite, and quartz grains showing probable shock features. This bed is interpreted as a channelized deposit of proximal ejecta. (2) A set of lenticular, massive, graded "laminated beds" contains intraclasts and abundant plant debris, and may be the result of megawave backwash that carried coarse debris from shallow parts of the continental margin into deeper water. (3) At the top, several thin "ripple beds" composed of fine sand are separated by clay drapes; they are interpreted as deposits of oscillating currents, perhaps a seiche. An iridium anomaly (921 +/- 23 pg/g) is observed at the top of the ripple beds. Our observations at the Mimbral locality support the hypothesis of a K-T impact on nearby Yucatan.

  10. Occupational stress and job satisfaction of healthcare staff in rehabilitation units.

    Science.gov (United States)

    Fiabane, Elena; Giorgi, Ines; Musian, D; Sguazzin, Cinzia; Argentero, P

    2012-01-01

    Occupational stress and job dissatisfaction are recognized risk factors for healthcare professionals and can lead to a decrease in work performance and in the quality of care offered, and to poorer health of workers. Research in the rehabilitation care setting is very limited and needs to be explored. To investigate occupational stress, job satisfaction and their relationships with organizational factors among healthcare staff in rehabilitation units. A cross-sectional study of healthcare staff working in two rehabilitation units was conducted. They were sent two self-administered questionnaires, the Occupational Stress Indicator (OSI) and the Areas of Work life Scale (AWS), in order to assess occupational stress and job satisfaction. One-way ANOVA was used to explore work stress among two groups of workers, characterized by high and low job satisfaction levels. Stepwise multiple linear regression analysis was conducted to assess the association between job satisfaction and organizational risk factors. A total of 90 questionnaires were returned (response rate 53%). The main sources of stress were unfairness, conflict between personal and organizational values, lack of reward and workload Workers with low job satisfaction significantly scored higher in work-related stress in regard to various aspects of work, and in lower job control. Regression analysis showed that the most important predictors of job satisfaction were fairness and workload. The results of this study showed that job dissatisfaction is strongly associated with work stress and certain organizational risk factors. This study suggests the importance of focusing on the psychosocial factors in the work environment and job satisfaction in order to improve the well-being of rehabilitation healthcare staff.

  11. Prospective Analysis of Risk Factors Related to Depression and Post Traumatic Stress Disorder in Deployed United States Navy Personnel

    Science.gov (United States)

    2011-03-28

    post traumatic stress disorder ( PTSD ) and depression (MDD) than...United States Several epidemiological studies have been conducted on the prevalence of post traumatic stress disorder ( PTSD ) and major depression in...forms contain the same 4-item screener for post - traumatic stress disorder ( PTSD ). This screener was developed by the National Center for PTSD and

  12. Differential antioxidative responses in transgenic peanut bear no relationship to their superior transpiration efficiency under drought stress.

    Science.gov (United States)

    Bhatnagar-Mathur, Pooja; Devi, M Jyostna; Vadez, Vincent; Sharma, Kiran K

    2009-07-15

    To counter the effects of environmental stresses, the plants must undergo detoxification that is crucial to avoid the accumulation of damaging free oxygen radicals (ROI). Here, we detail the oxidative damage, the antioxidant composition, and the osmoprotection achieved in transgenic plants of peanut overexpressing the AtDREB1A transgene, driven by a stress-inducible promoter (Atrd29A) when exposed to progressive water stress conditions. This study explored the biochemical mechanisms where (i) the antioxidants such as superoxide dismutase (SOD), ascorbate peroxidase (APOX), and glutathione reductase (GR) accumulated in the transgenic plants at comparably higher levels than their untransformed counterparts under dry soil conditions, (ii) a significant increase in the proline levels in the transgenic plants was observed in dry soils, and (iii) a dramatic increase in the lipid peroxidation in the untransformed controls in drier soils. Most of the biochemical parameters related to the antioxidative machinery in the tested peanut transgenics were triggered by the overexpression of AtDREB1A that appeared to differ from the untransformed controls. The antioxidants showed a negative correlation with the fraction of transpirable soil water (FTSW) thresholds, where the normalized transpiration rate (NTR) started decreasing in the tested plants. However, no significant relationship was observed between any of these biochemical indicators and the higher transpiration efficiency (TE) values found in the transgenic events. Our results show that changes in the antioxidative machinery in these transgenic peanut plants (overexpressing the AtDREB1A transcription factor) under water-limiting conditions played no causative role in improved TE.

  13. Sectoral contributions to surface water stress in the coterminous United States

    International Nuclear Information System (INIS)

    Averyt, K; Meldrum, J; Caldwell, P; Sun, G; McNulty, S; Huber-Lee, A; Madden, N

    2013-01-01

    Here, we assess current stress in the freshwater system based on the best available data in order to understand possible risks and vulnerabilities to regional water resources and the sectors dependent on freshwater. We present watershed-scale measures of surface water supply stress for the coterminous United States (US) using the water supply stress index (WaSSI) model which considers regional trends in both water supply and demand. A snapshot of contemporary annual water demand is compared against different water supply regimes, including current average supplies, current extreme-year supplies, and projected future average surface water flows under a changing climate. In addition, we investigate the contributions of different water demand sectors to current water stress. On average, water supplies are stressed, meaning that demands for water outstrip natural supplies in over 9% of the 2103 watersheds examined. These watersheds rely on reservoir storage, conveyance systems, and groundwater to meet current water demands. Overall, agriculture is the major demand-side driver of water stress in the US, whereas municipal stress is isolated to southern California. Water stress introduced by cooling water demands for power plants is punctuated across the US, indicating that a single power plant has the potential to stress water supplies at the watershed scale. On the supply side, watersheds in the western US are particularly sensitive to low flow events and projected long-term shifts in flow driven by climate change. The WaSSI results imply that not only are water resources in the southwest in particular at risk, but that there are also potential vulnerabilities to specific sectors, even in the ‘water-rich’ southeast. (letter)

  14. [Job satisfaction vs. occupational stress - Quantitative analysis of 3 organizational units of a public sector institution].

    Science.gov (United States)

    Rogozińska-Pawełczyk, Anna

    2018-05-22

    The influence of subjective perception of occupational stress and its individual factors on the overall level of job satisfaction was analyzed. The respondents were also asked to answer the question of the potential differences in terms of variables in managers and non-managers, and in various demographic factors. This article presents the results of a study conducted among 5930 people employed in 3 units of the examined public sector institution. The research was conducted using computer-assisted web interview method. The parameters of the polynomial model of ordered categories were estimated. The results showed a statistically significant effect between the variables and the differences between the groups of subjects. Analyzes showed slight differences between men and women. Employees with a low level of stress and high job satisfaction were noted in the oldest group, aged over 55 years, and in managers. Low levels of stress and job satisfaction were observed in young employees with the shortest period of employment. Among those least satisfied with the work and experiencing high levels of stress there were respondents with 6-15 years of employment in non-managerial positions. While the highest levels of stress and high satisfaction were found in people aged 46-55 years, with more than 20 years of work experience. The results of the estimation of the polynomial model parameters of ordered categories indicate that the level of perceived stress is related to the level of job satisfaction. The lower the level of stress and stressors in the workplace, the greater the job satisfaction in the surveyed unit. Med Pr 2018;69(3):301-315. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  15. Some genetic profiles in liver of Ehrlich ascites tumor-bearing mice under the stress of irradiation

    Directory of Open Access Journals (Sweden)

    Amal I. Hassan

    2014-04-01

    Full Text Available Radiation therapy aims to kill cancer cells with a minimum of normal tissue exposure. In an attempt to define the molecular and biochemical changes associated with exposure to radiotherapy, the objective of the present study is to explore the effect of gamma (γ irradiation on nuclear factor, erythroid 2 (NFE2, P53, stromelysin-1 (matrix metalloproteinase-3 (MMP3, BCL-2 and BAX genes expression in Ehrlich ascites carcinoma (EAC bearing mice. Various biochemical parameters such as liver function, H2O2, B% and T% lymphocytes, total antioxidants and MDA were investigated to evaluate their usefulness as possible during cancer treatment with radiotherapy. Rats were irradiated with a single whole body Cobalt 60-gamma radiation dose of 0.5 Gy. Sixty-four female mice, weighing 20–25 g were used in this study and divided into three main groups. The first group served as control group, while the second were injected intraperitoneally with EAC then was subdivided into two groups, II A and II B. The latter one (group II B, the animals were exposed to a single dose of 0.5 Gy whole body γ irradiation. The third main group, were irradiated with a single dose of 0.5 Gy whole body γ irradiation. Blood and liver tissue samples were collected at 4, 24 and 96 h post-irradiation. The gene expression levels in the livers of animals from each exposure group were compared individually with that of pooled sham-irradiated animals. MMP3 and NFE2 were overexpressed in liver samples of EAC group post 4, 24 and 96 h of γ irradiation (IIB. On the other hand, P53 and BCL-2 genes were downregulated by using RT-PCR analysis post 4, 24 and 96 h of γ irradiation (IIB. As well as, liver function and MDA were increased significantly in the γ - irradiation group (3rd group when compared to control mice (1st group. Gamma irradiation 3rd group revealed increase in the level of T% and B% lymphocytes. According to the obtained results, both γ rays and time period alter

  16. Stress, coping and burnout among Intensive Care Unit nursing staff: associated factors.

    Science.gov (United States)

    Andolhe, Rafaela; Barbosa, Ricardo Luis; Oliveira, Elaine Machado de; Costa, Ana Lúcia Siqueira; Padilha, Katia Grillo

    2015-02-01

    Objective To investigate emotional stress, coping and burnout among nursing staff and their association with biosocial factors and characteristics of work in Intensive Care Units (ICU). Method This was a cross-sectional study, conducted in eight ICUs at a teaching hospital in the city of São Paulo, Brazil, in October 2012. Biosocial data and information about the professionals' work was gathered, and they were given the Scale of Occupational Stress, Scale of Occupational Coping, List of Signs and Symptoms of Stress and the Maslach Burnout Inventory. Results The study sample consisted of 287 subjects, predominately women, with partners and children. Most professionals presented moderate stress levels and control as a coping strategy (74.47% and 79.93%, respectively), and burnout was present among 12.54%. Factors associated with stress were related to working conditions. The most prevalent protective factors were having a partner, working in the clinical ICU and liking work, while adequate amount of sleep was a protective factor for burnout. Conclusion Control of the working environment and adequate sleep are decisive and protective factors in dealing with situations of occupational stress.

  17. Bearing-Mounting Concept Accommodates Thermal Expansion

    Science.gov (United States)

    Nespodzany, Robert; Davis, Toren S.

    1995-01-01

    Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

  18. Stress, coping, and general health of nurses who work in units that assist AIDS-carriers and patients with

    OpenAIRE

    Da Silva Britto, Eliane; Pimenta Carvalho, Ana Maria

    2008-01-01

    Based on Lazarus and Folkman’s theory about stress and coping, this research aimed at answering questions related to how nurses, who work in two specialized units of a general hospital, evaluate their working environment, their health and how they manage with stressing situations. In the unit of infectious diseases, the nurses’ evaluation of their working environment did not surpass the limits of what is considered as acceptable. In the unit of hematological alterations, the results showed hi...

  19. Profiling spermatogenic failure in adult testes bearing Sox9-deficient Sertoli cells identifies genes involved in feminization, inflammation and stress

    Directory of Open Access Journals (Sweden)

    Barrionuevo Francisco

    2010-12-01

    Full Text Available Abstract Background Sox9 (Sry box containing gene 9 is a DNA-binding transcription factor involved in chondrocyte development and sex determination. The protein's absence in testicular Sertoli nurse cells has been shown to disrupt testicular function in adults but little is known at the genome-wide level about molecular events concomitant with testicular break-down. Methods To determine the genome-wide effect on mRNA concentrations triggered by the absence of Sox9 in Sertoli cells we analysed adult testicular tissue from wild-type versus mutant mice with high-density oligonucleotide microarrays and integrated the output of this experiment with regulatory motif predictions and protein-protein network data. Results We report the genome-wide mRNA signature of adult testes lacking Sox9 in Sertoli cells before and after the onset of late spermatogenic failure as compared to fertile controls. The GeneChip data integrated with evolutionarily conserved Sox9 DNA binding motifs and regulatory network data identified genes involved in feminization, stress response and inflammation. Conclusions Our results extend previous observations that genes required for female gonadogenesis are up-regulated in the absence of Sox9 in fetal Sertoli cells to the adult stage. Importantly, we identify gene networks involved in immunological processes and stress response which is reminiscent of a phenomenon occurring in a sub-group of infertile men. This suggests mice lacking Sox9 in their Sertoli cells to be a potentially useful model for adult human testicular failure.

  20. Perceived Stress and Professional Quality of Life in Neonatal Intensive Care Unit Nurses in Gujarat, India.

    Science.gov (United States)

    Amin, Amee A; Vankar, Jagdish R; Nimbalkar, Somashekhar M; Phatak, Ajay G

    2015-11-01

    To study the levels of perceived stress in Neonatal Intensive Care Unit (NICU) nurses and its association with professional quality of life domains viz. compassion satisfaction, burnout and secondary trauma. In this multicenter, cross sectional study, data was collected by surveying 129 nurses from nine NICUs across six cities of Gujarat, India using demographic questionnaire, Perceived Stress Scale (PSS14) and Professional Quality of Life Scale (ProQOL5) during July to September 2013. Descriptive statistics, correlation coefficient and multiple regression were used for analysis. The mean (SD) age of participants was 28.37 (8.20) y. Most were single, satisfied with salary benefits and reported 'good' to 'excellent' relationships at work. The mean (SD) duration of duty hours was 8.12 (0.76) h and 43.6% were attending to more than 4 patients/shift. The mean (SD) perceived stress level was 22.19 (7.17) [Range: 3 to 39]. High compassion satisfaction, high burnout, and high secondary traumatic stress were reported by 25 (19.4%), 30 (23.3%) and 30 (23.3%) nurses respectively. PSS14 was negatively correlated with compassion satisfaction (r = -0.28) and positively correlated with burnout (r = 0.43) and secondary traumatic stress (r = 0.24). Most of the nurses (91, 70.5%) were identified as perceiving moderate to high stress. Professional quality of life domains correlated with perceived stress. There is further need to study domains influencing NICU nurses' professional QOL. Identifying stress and QOL issues in NICU nurses can help formulate relevant policies.

  1. Iranian parent-staff communication and parental stress in the neonatal Intensive Care Unit.

    Science.gov (United States)

    Hasanpour, Marzieh; Alavi, Mousa; Azizi, Fatemeh; Als, Heidelise; Armanian, Amir Mohmmad

    2017-01-01

    The birth of an infant requiring hospitalization in the neonatal Intensive Care Unit (NICU) uniformly is reported to be stressful for parents and family members. This study aimed to determine parent-staff communication in the NICU and its relationship to parent stress. Two hundred and three Iranian parents with preterm infants hospitalized in the NICU participated in this descriptive-correlational study. The participants were selected by the quota sampling method. Data collected included a three-part: questionnaire, the first part covered demographic parent and infant information, the second was the Parent-Staff Communication Scale (the score of which ranged from 0 to 180), and the third was the Parental Stress Scale (the score of which ranged from 0 to 102). Descriptive and inferential statistics including the Pearson's correlation coefficient test were applied to the data, using SPSS software Version 16. This study revealed that fathers and mothers' stress and communication scores were almost comparable and both higher than expected. The total mean score of the two main variables, i.e., parent-staff communication and parental stress were, respectively, 100.72 ± 18.89 and 75.26 ± 17.6. A significant inverse correlation was found between parental stress and parent-staff communication scores ( r = -0.144, P = 0.041). Based on this study finding showed that better parent-staff communication is related to lower parent stress scores, it is recommended that nurses and physicians receive specific skill training for the establishment of effective parent-staff communication. It is anticipated that such improved staff skills will help decrease parent stress and therewith likely promote parent and infant health in the NICU.

  2. Association between burnout and cortisol secretion, perceived stress, and psychopathology in palliative care unit health professionals.

    Science.gov (United States)

    Fernández-Sánchez, José Carlos; Pérez-Mármol, José Manuel; Blásquez, Antonia; Santos-Ruiz, Ana María; Peralta-Ramírez, María Isabel

    2018-06-01

    ABSTRACTObjective:A high incidence of burnout has been reported in health professionals working in palliative care units. Our present study aims to determine whether there are differences in the secretion of salivary cortisol between palliative care unit health professionals with and without burnout, and to elucidate whether there is a relationship between burnout syndrome and perceived stress and psychopathological status in this population. A total of 69 health professionals who met the inclusion criteria participated in our study, including physicians, nurses, and nursing assistants. Some 58 were women (M = 29.65 years, SD = 8.64) and 11 men (M = 35.67 years, SD = 11.90). The level of daily cortisol was registered in six measurements taken over the course of a workday. Burnout syndrome was evaluated with the Maslach Burnout Inventory-Human Services Survey (MBI-HSS), the level of perceived stress was measured using the Perceived Stress Scale, and psychopathological status was gauged using the SCL-90-R Symptoms Inventory. There were statistically significant differences in secretion of cortisol in professionals with high scores on a single subscale of the MBI-HSS [F(3.5) = 2.48, p burnout showed higher scores on the psychopathology and stress subscales than professionals without it. A higher score in any dimension of the burnout syndrome in palliative care unit health professionals seems to be related to several physiological and psychological parameters. These findings may be relevant for further development of our understanding of the relationship between levels of burnout and cortisol secretion in the health workers in these units.

  3. Water stress and social vulnerability in the southern United States, 2010-2040

    Science.gov (United States)

    cassandra Johnson-Gaither; John Schelhas; Wayne Zipperer; Ge Sun; Peter V. Caldwell; Neelam Poudyal

    2014-01-01

    Water scarcities are striking in semiarid, subregions of the Southern United States such as Oklahoma and western Texas (Glennon 2009, Sabo et al. 2010). In Texas, water stress has been a constant concern since the 1950s when the state experienced severe drought conditions (Moore 2005). The nearly 2000-mile Rio Grande River, which forms part of the Texas–Mexico border,...

  4. Work stress, occupational burnout and depression levels: a clinical study of paediatric intensive care unit nurses in Taiwan.

    Science.gov (United States)

    Lin, Tzu-Ching; Lin, Huey-Shyan; Cheng, Su-Fen; Wu, Li-Min; Ou-Yang, Mei-Chen

    2016-04-01

    This study aimed to examine the relationship between work stress and depression; and investigate the mediating effect of occupational burnout among nurses in paediatric intensive care units. The relationships among work stress, occupational burnout and depression level have been explored, neither regarding occupational burnout as the mediating role that causes work stress to induce depression nor considering the paediatric intensive care unit context. A cross-sectional correlational design was conducted. One hundred and forty-four female paediatric intensive care unit nurses from seven teaching hospitals in southern Taiwan were recruited as the participants. Data were collected by structured questionnaires including individual demographics, the Nurse Stress Checklist, the Occupational Burnout Inventory and the Taiwan Depression Questionnaire. The results indicated that after controlling for individual demographic variables, the correlations of work stress with occupational burnout, as well as work stress and occupational burnout with depression level were all positive. Furthermore, occupational burnout may exert a partial mediating effect on the relationship between work stress and depression level. This study provides information about work stress, occupational burnout and depression level, and their correlations, as well as the mediating role of occupational burnout among paediatric intensive care unit nurses. It suggests government departments and hospital administrators when formulating interventions to prevent work stress and occupational burnout. These interventions can subsequently prevent episodes of depression in paediatric intensive care unit nurses, thereby providing patients with a safe and high-quality nursing environment. © 2016 John Wiley & Sons Ltd.

  5. Analysis of Ling'ao nuclear power station unit 1 exciter No.11 bearing white metal damage and its operating temperature abnormally high

    International Nuclear Information System (INIS)

    Jia Kaili

    2005-01-01

    On the base of analyzing the type of exciter No.11 bearing white metal damage, the root cause and its solution are found. No damage was found on bearing white metal in the later time. On the base of analyzing the structure of the generator end bracket, it is pointed out that when the generator frame is full of pressed gas, the end bracket will deform, that result in the load on No.11 bearing increase, as a result causes the bearing temperature high. A proposal to this problem is presented. (author)

  6. Geologic feasibility of selected chalk-bearing sequences within the conterminous United States with regard to siting of radioactive-waste repositories

    International Nuclear Information System (INIS)

    Gonzales, S.

    1975-11-01

    Various geologic and hydrologic parameters are evaluated in relation to assessing the potential for repository storage of high-level radioactive wastes within several stratigraphic sequences dominated by chalks and chalky limestones. The former lithology is defined as a carbonate rock consisting mainly of very fine-grained particles of micritic calcite. Although chalks also contain coarser-grained particles such as shells of fossil foraminifera and non-calcitic minerals like quartz, most contain more than 90 percent micritic material. The latter represents broken fossil coccolith plates. The chalk-dominated formations discussed are exposed and underlie two different physiographic provinces which nevertheless display a general similarity in both being regions of extensive plains. The Niobrara Formation occurs mainly within the Great Plains province, while the Austin Chalk of Texas and the Selma Group of Alabama and Mississippi are located in the western and eastern Gulf Coastal Plain, respectively. The preliminary assessment is that chalk-bearing sequences show some promise and are deserving of added consideration and evaluation. Containment for hundreds of thousands of years would seem possible given certain assumptions. The most promising units from the three studied are the Niobrara Formation and Selma Group. Regional and local conditions make the Austin more suspect

  7. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  8. Heat stress control in the TMI-2 [Three Mile Island Unit 2] defueling and decontamination activities

    International Nuclear Information System (INIS)

    Schork, J.S.; Parfitt, B.A.

    1988-01-01

    During the initial stages of the Three Mile Island Unit 2 (TMI-2) defueling and decontamination activities for the reactor building, it was realized that the high levels of loose radioactive contamination would require the use of extensive protective clothing by entry personnel. While there was no doubt that layered protective clothing protects workers from becoming contaminated, it was recognized that these same layers of clothing would impose a very significant heat stress burden. To prevent the potentially serious consequences of a severe reaction to heat stress by workers in the hostile environment of the TMI-2 reactor building and yet maintain the reasonable work productivity necessary to perform the recovery adequately, an effective program of controlling worker exposure to heat stress had to be developed. Body-cooling devices produce a flow of cool air, which is introduced close to the skin to remove body heat through convection and increased sweat evaporation. The cooling effect produced by the Vortex tube successfully protected the workers from heat stress, however, there were several logistical and operational problems that hindered extensive use of these devices. The last type of cooling garment examined was the frozen water garment (FWG) developed by Elizier Kamon at the Pennsylvania State University as part of an Electric Power Research Institute research grant. Personal protection, i.e., body cooling, engineering controls, and administrative controls, have been implemented successfully

  9. Clinical and epidemiological study of stress hyperglycemia among medical intensive care unit patients in Central India

    Directory of Open Access Journals (Sweden)

    Jitendra Sharma

    2017-01-01

    Full Text Available Background: Stress hyperglycemia is common in patients presenting at the emergency medical ward and is associated with poor prognosis and increased risk of mortality. Aims and Objective: To study and determine the prevalence and factors associated with stress hyperglycemia. Materials and Methods: A cross-sectional observational study was performed on 536 nondiabetic patients presented to the Intensive Care Unit (ICU at Gandhi Medical College and allied Hamidia Hospital, Bhopal, between March 31, 2015, and May 28, 2015. A detailed history including demographic profile, presence of chronic disease, history of hospitalization and ICU admission, surgical status, and major reason for ICU admission (i.e., predominant diagnostic category was collected. Hematological and other parameters based on profile of study population were also analyzed. Results: Out of 536 patients, 109 (20.33% had stress hyperglycemia. Out of 109 patients with stress hyperglycemia, 87 (16.23% patients had glycated hemoglobin (HbA1c <5.7% and 22 (4.10% patients had HbA1c between 5.7% and 6.4%. Mean age of the study population was 40.27 ± 1.44 years, with male dominance. Mean random blood glucose level was 181.46 ± 3.80 mg/dl. Frequency of stress hyperglycemia was 24.13% in stroke, 19.54% in multiple organ dysfunction syndrome (MODS, 17.24% in chronic kidney disease (CKD, 12.64% in central nervous system (CNS infection, 8.05% in chronic liver disease (CLD, and 8.05% in seizure patients. Association between stroke and stress hyperglycemia was significant (P = 0.036. Association between hospital stay more than 7 days and stress hyperglycemia was significant in stroke patients (P = 0.0029, CKD patients (P = 0.0036, CLD (P = 0.0099, and MODS patients (P = 0.0328. Conclusions: The factors associated with stress hyperglycemia were stroke, MODS, CKD, CNS infection, CLD, seizure patients, with prolonged hospital stay and expected proportion.

  10. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  11. Journal Bearings

    Directory of Open Access Journals (Sweden)

    Renato Brancati

    1999-01-01

    determined after acquiring and analysing the orbits described by the journal axis for assigned unbalance values in different operating conditions. Analysis of the results shows some particular operating features that were not entirely predicted by the theoretical model and which may give rise to malfunctions in the rotor-tilting pad bearings system. The tests were carried out in the rotor dynamics laboratory of the Dipartimento di Ingegneria Meccanica per l'Energetica at the University of Naples.

  12. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

  13. The Effect of Progressive Muscle Relaxation on The Occupational Stress of Nurses in Critical Care Units

    Directory of Open Access Journals (Sweden)

    Pegah Matourypour

    2012-10-01

    Full Text Available Background and objective: In the nursing profession, there are numerous factors which altogether cause occupational stress and as a result occupational exhaustion in nurses and decrease the quality of patient care. Regarding the importance of this issue which influences the health indices of the society, this study investigates the effect of progressive muscle relaxation on the occupational stress of nurses.Materials and Methods: This semi-experimental and before-after study was conducted using progressive muscle relaxation intervention on 33 nurses in special treatment (ICU and CCU and emergency units through simple sampling in Yazd in 2012. To assess occupational stress,Toft-Anderson questionnaire was used. The procedure of applying relaxation in a practical way was given to nurses in pamphlets and questionnaires were filled before and two weeks after the intervention. Analysis was done using SPSS.16 software and T-test.Results: The average total score of stress in nurses before and after the intervention was determined as – 28.12±43.74 and 52.12±04.72 respectively and this difference was not statistically significant (39.0>p. However, in the dimensions of nurses’ workload (/0>p 03 and t=2.27 and patients’ suffering and death, these scores were significantly different (0001.0>p and t=3.94.Conclusion: This study showed that applying progressive muscle relaxation technique as a method of emotion-focused coping cannot be effective in the reduction of occupational stress in nurses.

  14. Remedial investigation report on Bear Creek Valley Operable Unit 2 (rust spoil area, spoil area 1, and SY-200 yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 2. Appendixes

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    This document contains the appendices to the Remedial Investigation Report on Bear Creek Valley Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. The appendices include Current and historical soil boring and groundwater monitoring well information, well construction logs, and field change orders; Analytical data; Human health risk assessment data; and Data quality.

  15. Remedial investigation report on Bear Creek Valley Operable Unit 2 (rust spoil area, spoil area 1, and SY-200 yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 2. Appendixes

    International Nuclear Information System (INIS)

    1994-08-01

    This document contains the appendices to the Remedial Investigation Report on Bear Creek Valley Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. The appendices include Current and historical soil boring and groundwater monitoring well information, well construction logs, and field change orders; Analytical data; Human health risk assessment data; and Data quality

  16. Analyses of fecal and hair glucocorticoids to evaluate short- and long-term stress and recovery of Asiatic black bears (Ursus thibetanus) removed from bile farms in China.

    Science.gov (United States)

    Malcolm, K D; McShea, W J; Van Deelen, T R; Bacon, H J; Liu, F; Putman, S; Zhu, X; Brown, J L

    2013-05-01

    Demand for traditional Chinese medicines has given rise to the practice of maintaining Asiatic black bears (Ursus thibetanus) in captivity to harvest bile. We evaluated hypothalamic-pituitary-adrenal (HPA) activity in Asiatic black bears on a bile farm in China by measuring cortisol in hair. We also monitored hair and fecal glucocorticoid metabolites as bears acclimated to improved husbandry at the Animals Asia Foundation China Bear Rescue Center (CBRC) after removal from other bile farms. Fecal samples were collected twice weekly for ~1 year, and hair was obtained from bears upon arrival at the CBRC and again ≥163 days later. Paired hair samples showed declines in cortisol concentrations of 12-88% in 38 of 45 (84%, pbears after arrival and acclimation at the rehabilitation facility. Concentrations of cortisol in hair from bears on the bile farm were similar to initial concentrations upon arrival at the CBRC but were higher than those collected after bears had been at the CBRC for ≥163 days. Fecal glucocorticoid concentrations varied across months and were highest in April and declined through December, possibly reflecting seasonal patterns, responses to the arrival and socialization of new bears at the CBRC, and/or annual metabolic change. Data from segmental analysis of hair supports the first of these explanations. Our findings indicate that bears produced elevated concentrations of glucocorticoids on bile farms, and that activity of the HPA axis declined following relocation. Thus, hair cortisol analyses are particularly well suited to long-term, retrospective assessments of glucocorticoids in ursids. By contrast, fecal measures were not clearly associated with rehabilitation, but rather reflected more subtle endocrine changes, possibly related to seasonality. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Stress in parents of very low birth weight preterm infants hospitalized in neonatal intensive care units. A multicenter study.

    Science.gov (United States)

    Wormald, Francisca; Tapia, José L; Torres, Gabriela; Cánepa, Paula; González, María Aurelia; Rodríguez, Diana; Escobar, Marisol; Reyes, Bernardita; Capelli, Carola; Menéndez, Laura; Delgado, Patricia; Treuer, Sergio; Ramírez, Rodrigo; Borja, Norma; Domínguez, Angélica

    2015-08-01

    The birth of a premature baby is a stressful event for parents. The objective of this study was to determine early stress in parents of very low birth weight infants (VLBWIs) hospitalized in 12 neonatal intensive care units from a South American Neonatal Network, to identify associated factors, and to compare the level of parental stress in public versus private healthcare facilities. Cross-sectional study in mothers/fathers of VLBWIs (500 to 1500 g). Early parental stress was measured using the Parental Stressor Scale, with a score from 1 (low stress) to 5 (high stress). The sociodemographic characteristics of parents and newborn infants were collected and associated with levels of parental stress. The study included 273 fathers/mothers of a total of 218 VLBW preterm infants. The survey was administered at 5.9 ± 2.0 days of life. The average total parental stress was 3.1 ± 0.8, and the highest score was obtained for the parental role subscale (3.6). A lower education level, unemployment, not having held the newborn infant, and respiratory support requirement were associated with higher parental stress levels. Stress was higher among mothers than fathers, and at public facilities versus private ones. Among parents of VLBWIs, a moderate early parental stress was observed. Parental role alteration was the most relevant factor. Parental stress was higher among mothers and at public healthcare facilities. A greater sensitization, further research and interventions in this area are required.

  18. Ball Bearing Analysis with the ORBIS Tool

    Science.gov (United States)

    Halpin, Jacob D.

    2016-01-01

    Ball bearing design is critical to the success of aerospace mechanisms. Key bearing performance parameters, such as load capability, stiffness, torque, and life all depend on accurate determination of the internal load distribution. Hence, a good analytical bearing tool that provides both comprehensive capabilities and reliable results becomes a significant asset to the engineer. This paper introduces the ORBIS bearing tool. A discussion of key modeling assumptions and a technical overview is provided. Numerous validation studies and case studies using the ORBIS tool are presented. All results suggest the ORBIS code closely correlates to predictions on bearing internal load distributions, stiffness, deflection and stresses.

  19. Hospital Related Stress Among Patients Admitted to a Psychiatric In-patient Unit in India

    Directory of Open Access Journals (Sweden)

    Latha KS

    2011-04-01

    Full Text Available The psychiatric patient’s attitudes towards hospitalization have found an association between patient perceptions of the ward atmosphere and dissatisfaction. The aim of the study was to determine the aspects of stress related to hospitalization in inpatients admitted to a psychiatric facility. Fifty in-patients of both sexes admitted consecutively to a psychiatric unit in a General Hospital were asked to rate the importance of, and their satisfaction with, 38 different aspects of in-patient care and treatment. Results showed that the major sources of stress were related to having a violent patient near to his/her bed; being away from family; having to stay in closed wards; having to eat cold and tasteless food; losing income or job due to illness, being hospitalized away from home; not able to understand the jargons used by the clinical staff and not getting medication for sleep. A well-differentiated assessment of stress and satisfaction has implications for the evaluation of the quality of psychiatric care and for the improvement of in-patient psychiatric care.

  20. Posttraumatic stress disorder in children and their parents following admission to the pediatric intensive care unit: a review.

    Science.gov (United States)

    Nelson, Lara P; Gold, Jeffrey I

    2012-05-01

    To evaluate posttraumatic stress disorder in children who have been admitted to the pediatric intensive care unit and their families. Studies were identified through PubMed, MEDLINE, and Ovid. All descriptive, observational, and controlled studies with a focus on posttraumatic stress disorder and the pediatric intensive care unit were included. Posttraumatic stress disorder rates in children following admission to the pediatric intensive care unit were between 5% and 28%, while rates of posttraumatic stress disorder symptoms were significantly higher, 35% to 62%. There have been inconsistencies noted across risk factors. Objective and subjective measurements of disease severity were intermittently positively associated with development of posttraumatic stress disorder. There was a positive relationship identified between the child's symptoms of posttraumatic stress disorder and their parents' symptoms.The biological mechanisms associated with the development of posttraumatic stress disorder in children admitted to the pediatric intensive care unit have yet to be explored. Studies in children following burn or other unintentional injury demonstrate potential relationships between adrenergic hormone levels and a diagnosis of posttraumatic stress disorder. Likewise genetic studies suggest the importance of the adrenergic system in this pathway.The rates of posttraumatic stress disorder in parents following their child's admission to the pediatric intensive care unit ranged between 10.5% and 21%, with symptom rates approaching 84%. It has been suggested that mothers are at increased risk for the development of posttraumatic stress disorder compared to fathers. Objective and subjective measures of disease severity yielded mixed findings with regard to the development of posttraumatic stress disorder. Protective parental factors may include education or the opportunity to discuss the parents' feelings during the admission. Following admission to the pediatric intensive

  1. A General Discussion of Problems Related to the Determination of Concrete Armour Unit Stresses Including Specific Results related to Static and Dynamic Stresses in Dolosse

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1989-01-01

    Recent breakwater failures revealed the shortcomings of the traditional design procedures for concrete armour units. This paper deals with one of them, which can be expressed as the "lack of balance between the hydraulic stability of the armour layer and the mechanical strength or integrity...... of the units". This problem is related mainly to the slender types of armour units. The paper discusses the various types of loads, and the practical determination of the wave and gravity induced loads and stresses, especially the model test technique and its restrictions. Examples related to Dolosse...

  2. 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 ...

  3. Relationship between job stress level and coping strategies used by Hong Kong nurses working in an acute surgical unit.

    Science.gov (United States)

    Wang, Wenru; Kong, Amelia Wai Man; Chair, Sek Ying

    2011-11-01

    The aim of this study is to explore the relationship between job stress and coping strategies of Hong Kong nurses working in an acute surgical unit. This is a descriptive correlational study. Data were collected from 98 Hong Kong surgical nurses using the Nursing Stress Scale and the Jalowiec Coping Scale. Results showed that workload (M = 15.36), lack of support (M = 13.32), and inadequate preparation (M = 12.33) are the most common stressors for Hong Kong surgical nurses. The most frequent strategies used by nurses to cope with stress can be characterized as evasive (M = 19.23), confrontive (M = 17.46), and optimistic (M = 15.81), all of which are also rated as the most effective strategies in reducing stress levels. Only the confrontive, optimistic, supportant, and emotive coping strategies reveal significant correlations (p stress levels of nurses, whereas the evasive, fatalistic, palliative, and self-reliant strategies showed no significant correlation with stress levels (p > .05). Recognizing the impacts of job-related stress and making use of effective coping methods play a vital role in reducing nurse's stress. A change in leadership styles from the managerial level and reallocation of manpower may help reduce job stress. The use of confrontive and optimistic coping strategies in reducing job-related stress for surgical nurses should be advocated and promoted in their daily work. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. In-situ stress measurements in the earth's crust in the eastern United States

    International Nuclear Information System (INIS)

    Rundle, T.A.; Singh, M.M.; Baker, C.H.

    1987-04-01

    The US Nuclear Regulatory Commission requires that the design basis for vibratory ground motion should be determined through correlation of seismicity with tectonic structures or provinces (10CFR100, Appendix A). Such criteria are difficult to apply in the eastern United States, which experiences persistent low level seismicity, with occasional moderate to large earthquakes. This report presents the results of in-situ stress measurements conducted towards reducing this uncertainty at three (3) seismically active sites in the region, namely, near Moodus, Connecticut, around the Ramapo fault zone in New York and New Jersey, and in central Virginia. As far as possible, at each location one bore hole was drilled close to the ''apparent'' epicenter of the seismic activity and one outside the ''known'' seismic zone, so that the data obtained could be compared. The results obtained were very consistent both as to magnitude and direction. No attempt was made to correlate the in-situ stress measurements with the tectonic setting or seismic activity, since this was beyond the scope of this project. Extensive appendices report experimental data. 35 refs

  5. [Stress level assessment of the nursing staff in the Intensive Care Unit of a university hospital].

    Science.gov (United States)

    Carrillo-García, C; Ríos-Rísquez, M I; Martínez-Hurtado, R; Noguera-Villaescusa, P

    2016-01-01

    The objective was to determine the work stress level among nursing staff in the Intensive Care Unit of a university hospital and to analyse its relationship with the various sociodemographic and working variables of the studied sample. A study was designed using a quantitative, descriptive and cross-sectional approach. The target population of the study was the nursing staff selected by non-random sampling. The instrument used was the Job Content Questionnaire. Data analysis was performed using SPSS 20. The mean, ranges and standard deviation for each of the variables were calculated. A bivariate analysis was also performed on the social and occupational variables of the sample. The participation rate was 80.90% (N=89). The mean of the Social support dimension was 3.13±0.397, for the Psychological demands at work dimension it was 3.10±0.384, with a mean of 2.96±0.436 being obtained for the Control over the work dimension. In the analysis of sociodemographic and work variables of the sample, only the professional category was significant, with nurses recording higher values in perception of job demands and control over their work compared to nursing assistants. In conclusion, there is a moderate perception of work stress in the analysed group of professionals. Among the sources of stress in the workplace was the low control in decision-making by practitioners, as well as the need to continually learn new things. On the other hand, the support received from colleagues is valued positively by the sample. Copyright © 2016 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

  6. Symptoms of Psychological Distress and Post-Traumatic Stress Disorder in United States Air Force Drone Operators

    Science.gov (United States)

    2014-08-01

    Disorder in United States Air Force “ Drone ” Operators 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...referred to as “ drones .” Participants were assessed for self-reported sources of occupational stress, levels of clinical distress using the Outcome...providers are discussed. 15. SUBJECT TERMS Stress, drone operator, PTSD, USAF 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

  7. Pathologies in the extinct Pleistocene Eurasian steppe lion Panthera leo spelaea ()-Results of fights with hyenas, bears and lions and other ecological stresses.

    Science.gov (United States)

    Rothschild, Bruce M; Diedrich, Cajus G

    2012-12-01

    Late Pleistocene Eurasian steppe lions Panthera leo spelaea (Goldfuss, 1810) frequently (3 of 13) have skull damage attributable to bites. Such evidence is found only in lions from hyena or cave bear dens. Wounds on frontal and parietal bones appear to be the result of battles during cave bear hunts, by antagonistic conflicts with hyenas, and less often from fights with conspecifics. Skull bite damage is extremely rare in modern lions, suggesting that this Eurasian lion pathology is the result of inter-specific (with cave bears) rather than intra-specific conflicts. The sex specificity of maxillary porosity (found only in lions among modern felidae) is also documented in its close genetic relation, P. l. spelaea. The pattern of skeletal exostotic reaction reveals them to have been pursuit rather than ambush predators. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Development of a screening measure of stress for parents of children hospitalised in a Paediatric Intensive Care Unit.

    Science.gov (United States)

    Rodríguez-Rey, Rocío; Alonso-Tapia, Jesús

    2016-08-01

    Having a child admitted to intensive care is a highly stressful experience for parents; however there is a lack of screening instruments of parental stress in that context, which would be useful for both, research and clinical purposes. (1) To validate a brief measure of parental stress based on the Parental Stressor Scale: Paediatric Intensive Care Unit (PSS:PICU), (2) to study which environmental factors of the PICU are more stressful in a sample of Spanish parents, and (3) to study which variables are related to higher levels of stress among this group. 196 Spanish parents completed the Abbreviated PSS: PICU (A-PSS:PICU) and a general stress scale (the Perceived Stress Scale) upon their child's discharge to test the convergent validity of the tool. Three months later, they were assessed anxiety and depression using the Hospital Anxiety and Depression Scale, and posttraumatic stress with the Davidson Trauma Scale in order to test the predictive validity of the A-PSS:PICU. Two factors emerged from Confirmatory Factor Analyses, (1) stress due to child's condition and (2) stress related to PICU's staff. The A-PSS:PICU showed adequate reliability and convergent and predictive validity. The most stressful aspects were the behaviours and emotional responses of their child and the loss of their parental role. Age, gender, child's condition, length of admission, spiritual beliefs, and mechanical ventilation were associated to parental stress scores. The A-PSS:PICU is a reliable and valid measure. Parental stress should be screened during a child's PICU admission to identify parents at risk of post-discharge distress. Copyright © 2016 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.

  9. Measurement of Family-centered care perception and parental stress in a neonatal unit.

    Science.gov (United States)

    Balbino, Flávia Simphronio; Balieiro, Maria Magda Ferreira Gomes; Mandetta, Myriam Aparecida

    2016-08-08

    to evaluate the effects of the implementation of the Patient and Family-Centered Care Model on parents and healthcare perceptions and parental stress. a quasi-experimental study developed in a neonatal unit of a university hospital in the municipality of São Paulo, Brazil, with the implementation of this model of care. Data collection were performed by two sample groups, one using non-equivalent groups of parents, and another using equivalent groups of healthcare professionals. The instruments Perceptions of Family-Centered Care-Parent Brazilian Version, Perceptions of Family-Centered Care-Staff Brazilian Version and Parental Stress Scale: Neonatal Intensive Care Unit, were applied to 132 parents of newborns hospitalized and to 57 professionals. there was a statistically significant improvement in the perceptions of the parents in most items assessed (p ≤0,05) and for the staff in relation to the family welcome in the neonatal unit (p = 0.041) and to the comprehension of the family's experience with the infant´s hospitalization (p = 0,050). There was a reduction in the average scores of parental stress, with a greater decrease in the Alteration in Parental Role from 4,2 to 3,8 (p = 0,048). the interventions improved the perceptions of parents and healthcare team related to patient and family-centered care and contributed to reducing parental stress. avaliar os efeitos da implementação do Modelo do Cuidado Centrado no Paciente e Família na percepção de pais e profissionais de saúde e no estresse parental. Estudo quase experimental com grupos não equivalentes para avaliação dos efeitos da intervenção na percepção de pais; e com grupos equivalentes para a avaliação na percepção de profissionais de saúde, desenvolvido na unidade neonatal de um hospital universitário do município de São Paulo. Os instrumentos, Percepção do Cuidado Centrado na Família- Pais versão brasileira, Percepção do Cuidado Centrado na Família- Equipe vers

  10. Rolling Bearing Life Prediction, Theory, and Application

    Science.gov (United States)

    Zaretsky, Erwin V.

    2016-01-01

    A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable

  11. Addendum to the remedial investigation report on Bear Creek Valley Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge Y-12 Plant Oak Ridge, Tennessee. Volume 1: Main text

    International Nuclear Information System (INIS)

    1995-04-01

    This addendum to the Remedial Investigation (RI) Report on Bear Creek Valley Operable Unit (OU) 2 at the Oak Ridge Y-12 Plant was prepared in accordance with requirements under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) for reporting the results of a site characterization for public review. This addendum is a supplement to a document that was previously issued in January 1995 and that provided the Environmental Restoration Program with information about the results of the 1993 investigation performed at OU 2. The January 1995 D2 version of the RI Report on Bear Creek Valley OU 2 included information on risk assessments that have evaluated impacts to human health and the environment. Information provided in the document formed the basis for the development of the Feasibility Study Report. This addendum includes revisions to four chapters of information that were a part of the document issued in January 1995. Specifically, it includes revisions to Chaps. 2, 3, 4, and 9. Volume 1 of this document is not being reissued in its entirety as a D3 version because only the four chapters just mentioned have been affected by requested changes. Note also that Volume 2 of this RI Report on Bear Creek Valley OU 2 is not being reissued in conjunction with Volume 1 of this document because there have been no changes requested or made to the previously issued version of Volume 2 of this document.

  12. Development and validation of the Acculturative Stress Scale for Chinese College Students in the United States (ASSCS).

    Science.gov (United States)

    Bai, Jieru

    2016-04-01

    Chinese students are the biggest ethnic group of international students in the United States. This study aims to develop a reliable and valid scale to accurately measure their acculturative stress. A 72-item pool was sent online to Chinese students and a five-factor scale of 32 items was generated by exploratory factor analysis. The five factors included language insufficiency, social isolation, perceived discrimination, academic pressure, and guilt toward family. The Acculturative Stress Scale for Chinese Students demonstrated high reliability and initial validity by predicting depression and life satisfaction. It was the first Chinese scale of acculturative stress developed and validated among a Chinese student sample in the United States. In the future, the scale can be used as a diagnostic tool by mental health professionals and a self-assessment tool by Chinese students. (c) 2016 APA, all rights reserved.

  13. The Effects of Aromatherapy on Intensive Care Unit Patients’ Stress and Sleep Quality: A Nonrandomised Controlled Trial

    Directory of Open Access Journals (Sweden)

    Eun Hee Cho

    2017-01-01

    Full Text Available Background. Stress has both physiological and psychological effects and can negatively impact patients’ treatment and recovery. We examined whether the aromatherapy alleviated patients’ stress and improved their sleep quality and provided data that can be utilized in clinical settings. Methods. This was a nonrandomised controlled experimental study. Participants included lucid adult patients who were admitted to the intensive care unit and had spent more than two nights there. The experimental treatment required participants to engage in deep breathing with essential oils as part of the aromatherapy. The control group was instructed to go to sleep without receiving the lavender aroma oil. Results. The experimental group and control group showed a significant difference in perceived stress (F=60.11, p<.001, objective stress index (F=25.65, p<.001, systolic blood pressure (F=9.09, p<.001, diastolic blood pressure (F=2.47, p=.046, heart rate (F=5.71, p<.001, and sleep quality (F=109.46, p<.001. Conclusions. The results revealed that aromatherapy alleviated stress and improved sleep quality in intensive care unit patients after 2 days of the experimental treatment. These results demonstrate that aromatherapy affects stress and sleep quality, thus indicating its value in nursing interventions. This trial is registered with KCT0002344.

  14. Pain-related stress in the Neonatal Intensive Care Unit and salivary cortisol reactivity to socio-emotional stress in 3-month-old very preterm infants.

    Science.gov (United States)

    Provenzi, Livio; Giusti, Lorenzo; Fumagalli, Monica; Tasca, Hilarj; Ciceri, Francesca; Menozzi, Giorgia; Mosca, Fabio; Morandi, Francesco; Borgatti, Renato; Montirosso, Rosario

    2016-10-01

    Very preterm (VPT) infants are hospitalized in the Neonatal Intensive Care Unit (NICU) and exposed to varying levels of skin-breaking procedures (pain-related stress), even in absence of severe clinical conditions. Repeated and prolonged pain exposure may alter hypothalamic-pituitary-adrenal (HPA) axis reactivity in VPT infants. During the post-discharge period, altered HPA axis reactivity has been documented in response to non-social stressors, using salivary cortisol as a biomarker. However, little is known about the effects of NICU pain-related stress on subsequent HPA axis reactivity to socio-emotional stress in infants. We examined the relationship between pain-related stress in NICU and HPA axis reactivity (i.e., salivary cortisol reactivity) to an age-appropriate socio-emotional condition in 37 healthy VPT infants compared to 53 full-term (FT) controls. The number of skin-breaking procedures was obtained across NICU stay for VPT infants. At 3 months (corrected age for prematurity), all infants participated in the maternal Face-to-Face Still-Face (FFSF) procedure, in order to assess HPA axis reactivity to socio-emotional stress (i.e., maternal unresponsiveness). VPT infants exhibited a blunted salivary cortisol reactivity, which was associated with the amount of skin-breaking procedures during NICU: greater pain-related stress predicted lower salivary cortisol reactivity, adjusting for neonatal confounders. These findings further advance our knowledge of how early exposure to pain-related stress in NICU contributes to the programming of an altered HPA axis reactivity to socio-emotional stress in 3-month-old VPT infants, even in the absence of major perinatal complications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Integrating occupational therapy in treating combat stress reaction within a military unit: An intervention model.

    Science.gov (United States)

    Gindi, Shahar; Galili, Giora; Volovic-Shushan, Shani; Adir-Pavis, Shirly

    2016-01-01

    Combat stress reaction (CR) is a syndrome with a wide range of symptoms including changes in soldiers' behaviors, emotional and physiological responses, avoidance and a decrease in both personal and military functioning. The short-term goal in treating CR is a speedy return to healthy functioning, whereas the long-term goal is to prevent the development of PTSD. Previous research has indicated that the achievement of this short-term goal affects the achievement of the long-term goal and vice versa. Effective treatment requires intervention by trained professionals proficient in reinforcing personal and functional identity without psychiatric labelling. The present paper presents a therapeutic model integrating OT in treating CR within a military setting. The model emphasizes the importance of preventing fixation to the role of 'patient' and a rapid return to maximal functioning. Based on Kielhofner's Model of Human Occupation, which aims to promote adaptive and efficient functioning by engaging soldiers in tasks supporting their military identity, empowering functionality, and increasing their perceived competency. The model emphasizes the therapeutic milieu within a military environment. Practical application of this model focuses on interdisciplinary aspects and client-focused application. The paper describes an assessment process for each soldier entering the CR unit and a treatment model integrating OT.

  16. Effect of the clinical support nurse role on work-related stress for nurses on an inpatient pediatric oncology unit.

    Science.gov (United States)

    Chang, Ann; Kicis, Jennifer; Sangha, Gurjit

    2007-01-01

    High patient acuity, heavy workload, and patient deaths can all contribute to work-related stress for pediatric oncology nurses. A new leadership role, the clinical support nurse (CSN), was recently initiated on the oncology unit of a large Canadian pediatric hospital to support frontline staff and reduce some of the stresses related to clinical activity. The CSN assists nurses with complex patient care procedures, provides hands-on education at the bedside, and supports staff in managing challenging family situations. This study explores the effect of the CSN role on the nurses' work-related stress using the Stressor Scale for Pediatric Oncology Nurses. A total of 58 nurses participated in this study for a response rate of 86%. The results show that the intensity of work-related stress experienced by nurses in this study is significantly less (P < .001) on shifts staffed with a CSN compared with shifts without a CSN.

  17. Are students' symptoms and health complaints associated with perceived stress at university? Perspectives from the United Kingdom and Egypt.

    Science.gov (United States)

    El Ansari, Walid; Oskrochi, Reza; Haghgoo, Ghollamreza

    2014-09-26

    This cross-sectional survey assessed and compared by country, the levels and correlates of 21 self-reported symptoms/health complaints. We examined the associations between self-reported symptoms and perceived stress. Data was collected from universities in the United Kingdom and Egypt (N = 3706 and 3271 undergraduates, respectively). A self-administered questionnaire assessed a range of self-reported symptoms, perceived stress, sociodemographic (gender, age, marital status, year of study, living arrangements during semester, income sufficiency), lifestyle (tobacco smoking, illicit drug/s use, alcohol consumption frequency), and health variables (subjective health status, health awareness, BMI), along with religiosity, and quality of life. Factor analysis categorized the 21 self-reported symptoms into four components. Correlation analysis and linear regression tested the associations between the self-reported symptoms and stress. Factor analysis of the health symptoms generated four symptom groups for each of the UK and Egypt (psychological; circulatory/breathing; gastrointestinal; and, pains/aches), and factor loadings were quite similar for both countries. Whilst the two samples showed similarities as to the kind of symptoms most frequently reported by students, the Egyptian sample had significantly higher frequency than the UK for every symptom. Frequent complaints (both countries) included difficulties to concentrate, fatigue, headaches, nervousness/anxiety, and back pain (UK) and mood swings (Egypt). Significantly more Egyptian students reported ≥ 4 symptoms over the past year than the UK. For each of the UK and Egypt, across each of the four symptom groups, there was a stepladder appearance whereby the frequency of symptoms increased with increasing quartiles of perceived stress. Not controlling for other variables, for both countries, there were significant positive correlations between each of the four symptom groups and stress; the highest correlation

  18. Are Students’ Symptoms and Health Complaints Associated with Perceived Stress at University? Perspectives from the United Kingdom and Egypt

    Directory of Open Access Journals (Sweden)

    Walid El Ansari

    2014-09-01

    Full Text Available This cross-sectional survey assessed and compared by country, the levels and correlates of 21 self-reported symptoms/health complaints. We examined the associations between self-reported symptoms and perceived stress. Data was collected from universities in the United Kingdom and Egypt (N = 3706 and 3271 undergraduates, respectively. A self-administered questionnaire assessed a range of self-reported symptoms, perceived stress, sociodemographic (gender, age, marital status, year of study, living arrangements during semester, income sufficiency, lifestyle (tobacco smoking, illicit drug/s use, alcohol consumption frequency, and health variables (subjective health status, health awareness, BMI, along with religiosity, and quality of life. Factor analysis categorized the 21 self-reported symptoms into four components. Correlation analysis and linear regression tested the associations between the self-reported symptoms and stress. Factor analysis of the health symptoms generated four symptom groups for each of the UK and Egypt (psychological; circulatory/breathing; gastrointestinal; and, pains/aches, and factor loadings were quite similar for both countries. Whilst the two samples showed similarities as to the kind of symptoms most frequently reported by students, the Egyptian sample had significantly higher frequency than the UK for every symptom. Frequent complaints (both countries included difficulties to concentrate, fatigue, headaches, nervousness/anxiety, and back pain (UK and mood swings (Egypt. Significantly more Egyptian students reported ≥4 symptoms over the past year than the UK. For each of the UK and Egypt, across each of the four symptom groups, there was a stepladder appearance whereby the frequency of symptoms increased with increasing quartiles of perceived stress. Not controlling for other variables, for both countries, there were significant positive correlations between each of the four symptom groups and stress; the highest

  19. Are Students’ Symptoms and Health Complaints Associated with Perceived Stress at University? Perspectives from the United Kingdom and Egypt

    Science.gov (United States)

    El Ansari, Walid; Oskrochi, Reza; Haghgoo, Ghollamreza

    2014-01-01

    This cross-sectional survey assessed and compared by country, the levels and correlates of 21 self-reported symptoms/health complaints. We examined the associations between self-reported symptoms and perceived stress. Data was collected from universities in the United Kingdom and Egypt (N = 3706 and 3271 undergraduates, respectively). A self-administered questionnaire assessed a range of self-reported symptoms, perceived stress, sociodemographic (gender, age, marital status, year of study, living arrangements during semester, income sufficiency), lifestyle (tobacco smoking, illicit drug/s use, alcohol consumption frequency), and health variables (subjective health status, health awareness, BMI), along with religiosity, and quality of life. Factor analysis categorized the 21 self-reported symptoms into four components. Correlation analysis and linear regression tested the associations between the self-reported symptoms and stress. Factor analysis of the health symptoms generated four symptom groups for each of the UK and Egypt (psychological; circulatory/breathing; gastrointestinal; and, pains/aches), and factor loadings were quite similar for both countries. Whilst the two samples showed similarities as to the kind of symptoms most frequently reported by students, the Egyptian sample had significantly higher frequency than the UK for every symptom. Frequent complaints (both countries) included difficulties to concentrate, fatigue, headaches, nervousness/anxiety, and back pain (UK) and mood swings (Egypt). Significantly more Egyptian students reported ≥4 symptoms over the past year than the UK. For each of the UK and Egypt, across each of the four symptom groups, there was a stepladder appearance whereby the frequency of symptoms increased with increasing quartiles of perceived stress. Not controlling for other variables, for both countries, there were significant positive correlations between each of the four symptom groups and stress; the highest correlation was

  20. Development and Evaluation of Titanium Spacesuit Bearings

    Science.gov (United States)

    Rhodes, Richard; Battisti, Brian; Ytuarte, Raymond, Jr.; Schultz, Bradley

    2016-01-01

    The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an

  1. Stressful life events are associated with insulin resistance among Chinese immigrant women in the United States

    Directory of Open Access Journals (Sweden)

    Carolyn Y. Fang

    2015-01-01

    Conclusions: This is one of the first studies to examine the associations between psychosocial stress and insulin resistance in Chinese immigrant women. These findings contribute to a growing body of literature on stress and diabetes risk in an immigrant population.

  2. Relationship of perceived stress with depression: complete mediation by perceived control and anxiety in Iran and the United States.

    Science.gov (United States)

    Ghorbani, Nima; Krauss, Stephen W; Watson, P J; Lebreton, Daniel

    2008-12-01

    This study sought to clarify the importance and cross-cultural relevance of associations between generalized perceived stress and depression. Also tested was the hypothesis that perceived stress would correlate more strongly with anxiety than with depression, whereas control would be more predictive of depression than of anxiety. Relationships between perceived stress, anxiety, depression, and perceived control were examined in samples of Iranian (n = 191) and American (n = 197) undergraduates. Correlations among these variables were generally similar across the two societies. Perceived stress did predict anxiety better than depression, but perceptions of control predicted depression significantly better than anxiety only in the United States. Best fitting structural equation models revealed that anxiety and perceived control completely accounted for the linkage between perceived stress and depression in both societies. An equally acceptable and more parsimonious model described perceived stress as a consequence rather than as an antecedent of anxiety and perceived control. Structural equation models were essentially identical across the two cultures except that internal control displayed a significant negative relationship with anxiety only in Iran. This result seemed to disconfirm any possible suggestion that a supposedly individualistic process like internal control could have no noteworthy role within a presumably more collectivistic Muslim society like Iran. Overall, these data documented the importance of anxiety and perceived control in explaining the perceived stress-depression relationship cross-culturally and therefore questioned the usefulness of perceived stress in predicting depression. Whether this understanding of the stress-depression relationship deserves general acceptance will require additional studies that measure the frequency of stressful life events and that utilize a longitudinal design.

  3. 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…

  4. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

  5. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

  6. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  7. Technical Development Path for Gas Foil Bearings

    Science.gov (United States)

    Dellacorte, Christopher

    2016-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  8. The Effects of Aromatherapy on Intensive Care Unit Patients' Stress and Sleep Quality: A Nonrandomised Controlled Trial

    Science.gov (United States)

    Cho, Eun Hee; Lee, Mi-Young

    2017-01-01

    Background Stress has both physiological and psychological effects and can negatively impact patients' treatment and recovery. We examined whether the aromatherapy alleviated patients' stress and improved their sleep quality and provided data that can be utilized in clinical settings. Methods This was a nonrandomised controlled experimental study. Participants included lucid adult patients who were admitted to the intensive care unit and had spent more than two nights there. The experimental treatment required participants to engage in deep breathing with essential oils as part of the aromatherapy. The control group was instructed to go to sleep without receiving the lavender aroma oil. Results The experimental group and control group showed a significant difference in perceived stress (F = 60.11, p aromatherapy alleviated stress and improved sleep quality in intensive care unit patients after 2 days of the experimental treatment. These results demonstrate that aromatherapy affects stress and sleep quality, thus indicating its value in nursing interventions. This trial is registered with KCT0002344. PMID:29375641

  9. Fatigue life of drilling bit bearings under arbitrary random loads

    Energy Technology Data Exchange (ETDEWEB)

    Talimi, M.; Farshidi, R. [Calgary Univ., AB (Canada)

    2009-07-01

    A fatigue analysis was conducted in order to estimate the bearing life of a roller cone rock bit under arbitrary random loads. The aim of the study was to reduce bearing failures that can interrupt well operations. Fatigue was considered as the main reason for bearing failure. The expected value of cumulative fatigue damage was used to estimate bearing life. An equation was used to express the relation between bearing life and bearing load when the bearing was subjected to a steady load and constant speed. The Palmgren-Miner hypothesis was used to determine the ultimate tensile strength of the material. The rain flow counting principle was used to determine distinct amplitude cycles. Hertzian equations were used to determine maximum stress loads. Fourier series were used to obtain simple harmonic functions for estimating stress-life relations. It was concluded that the method can be used during the well planning phase to prevent bearing failures. 6 refs.

  10. Covalently linked bisporphyrins bearing tetraphenylporphyrin and ...

    Indian Academy of Sciences (India)

    Covalently linked bisporphyrins bearing tetraphenylporphyrin and perbromoporphyrin units: Synthesis and their properties. Puttaiah Bhyrappa V Krishnan ... yields of the TPP moiety. Electrochemical redox and fluorescence data seem to suggest the possible existence of intramolecular interactions in these bisporphyrins.

  11. Effect of feed rate, workpiece hardness and cutting edge on subsurface residual stress in the hard turning of bearing steel using chamfer + hone cutting edge geometry

    International Nuclear Information System (INIS)

    Hua Jiang; Shivpuri, Rajiv; Cheng Xiaomin; Bedekar, Vikram; Matsumoto, Yoichi; Hashimoto, Fukuo; Watkins, Thomas R.

    2005-01-01

    Residual stress on the machined surface and the subsurface is known to influence the service quality of a component, such as fatigue life, tribological properties, and distortion. Therefore, it is essential to predict and control it for enhanced performance. In this paper, a newly proposed hardness based flow stress model is incorporated into an elastic-viscoplastic finite element model of hard turning to analyze process variables that affect the residual stress profile of the machined surface. The effects of cutting edge geometry and workpiece hardness as well as cutting conditions, such as feed rate and cutting speed, are investigated. Numerical analysis shows that hone edge plus chamfer cutting edge and aggressive feed rate help to increase both compressive residual stress and penetration depth. These predictions are validated by face turning experiments which were conducted using a chamfer with hone cutting edge for different material hardness and cutting parameters. The residual stresses under the machined surface are measured by X-ray diffraction/electropolishing method. A maximum circumferential residual stress of about 1700 MPa at a depth of 40 μm is reached for hardness of 62 HRc and feed rate of 0.56 mm/rev. This represents a significant increase from previously reported results in literatures. It is found from this analysis that using medium hone radius (0.02-0.05 mm) plus chamfer is good for keeping tool temperature and cutting force low, while obtaining desired residual stress profile

  12. 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 ...

  13. Stress and coping among surgical unit nurses of a teaching hospital

    Directory of Open Access Journals (Sweden)

    Laura de Azevedo Guido

    2012-06-01

    Full Text Available This study aimed at identifying the stressors, the level of stress and coping strategies used by nurses in a surgical clinic of a university hospital. It is a cross-sectional study whose population consisted of nine nurses. Data were collected, between May and June 2005, through the Survey Form for Daily Activities and Coping Strategies Inventory. It was verified that activities related to personnel management were valued as the most stressful. Indicating a nurse in a state of alert for high levels of stress was valued like three medium levels and five with low level of stress. It was observed that solving problems was the most commonly used factor to face stress. Knowledge of the stressors and the ways of coping with them can help assist in the development of possible solutions to minimize their effects and become the most productive and less stressful aspect of the daily life.

  14. Job Stress in the United Kingdom: Are Small and Medium-Sized Enterprises and Large Enterprises Different?

    Science.gov (United States)

    Lai, Yanqing; Saridakis, George; Blackburn, Robert

    2015-08-01

    This paper examines the relationships between firm size and employees' experience of work stress. We used a matched employer-employee dataset (Workplace Employment Relations Survey 2011) that comprises of 7182 employees from 1210 private organizations in the United Kingdom. Initially, we find that employees in small and medium-sized enterprises experience lower level of overall job stress than those in large enterprises, although the effect disappears when we control for individual and organizational characteristics in the model. We also find that quantitative work overload, job insecurity and poor promotion opportunities, good work relationships and poor communication are strongly associated with job stress in the small and medium-sized enterprises, whereas qualitative work overload, poor job autonomy and employee engagements are more related with larger enterprises. Hence, our estimates show that the association and magnitude of estimated effects differ significantly by enterprise size. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Impact of role-, job- and organizational characteristics on Nursing Unit Managers' work related stress and well-being.

    Science.gov (United States)

    Van Bogaert, Peter; Adriaenssens, Jef; Dilles, Tinne; Martens, Daisy; Van Rompaey, Bart; Timmermans, Olaf

    2014-11-01

    To study the impact of role, job- and organizational characteristics on nurse managers' work related stress and well-being such as feelings of emotional exhaustion, work engagement, job satisfaction and turnover intention. Various studies investigated role-, job- and organizational characteristics influencing nurse-related work environments. Research on nurse managers' related work environments define influencing factors, but, a clear understanding of the impact of nurse-managers' work-environment characteristics on their work related stress and well-being is limited. A cross-sectional design with a survey. A cross-sectional survey (N = 365) was carried out between December 2011-March 2012. The questionnaire was based on various validated measurement instruments identified by expert meetings (e.g. staff nurses, nurse managers and executives and physicians). Hierarchical regression analyses were performed using emotional exhaustion, work engagement, job satisfaction and turnover intentions as outcome variables. Study results showed one out of six nursing unit managers have high to very high feelings of emotional exhaustion and two out of three respondents have high to very high work engagement. Hierarchical regression models showed that role conflict and role meaningfulness were strong predictors of nursing unit managers' work related stress and well-being, alongside with job- and organizational characteristics. Several risk factors and stimulating factors influencing nurse unit managers' work related stress and well-being were identified. Further challenges will be to develop proper interventions and strategies to support nursing unit managers and their team in daily practice to deliver the best and safest patient care. © 2014 John Wiley & Sons Ltd.

  16. Numerical modelling of forces, stresses and breakages of concrete armour units

    NARCIS (Netherlands)

    Latham, John Paul; Xiang, Jiansheng; Anastasaki, Eleni; Guo, Liwei; Karantzoulis, Nikolaos; Viré, A.C.; Pain, Christopher

    2014-01-01

    Numerical modelling has the potential to probe the complexity of the interacting physics of rubble mound armour systems. Through forward modelling of armour unit packs, stochastic variables such as unit displacement and maximum contact force per unit during an external oscillatory disturbance can

  17. Relationship between Occupational Stress and the Performance of Health Care Units in Hamadan Health Center, Iran

    Directory of Open Access Journals (Sweden)

    Yadollah Hamidi

    2017-11-01

    conclusion: Regarding the confirmation of relationship between stress level and staff performance that shown in this study, and the fact that human resources are the key factor in determining the quality, accessibility and cost of health care, it is recommended that managers take effective actions for reducing stress and increasing productivity planning.

  18. [Depression and post-traumatic stress disorder among patients in intensive care units].

    Science.gov (United States)

    Asimakopoulou, E; Madianos, M

    2014-01-01

    Recent progress in medicine and technology has produced a significant increase in the survival rate of critically ill patients who have been treated in Intensive Care Units (ICU). Consequently, researchers have become increasingly interested in the relationship between critical illness and psychiatric consequences. The experience of critical illness has been often associated with Major Depression (MD) and Post-Traumatic Stress Disorder (PTSD). There has been no similar study in Greece. The aim of the present study was to investigate the prevalence of MD and PTSD among patients after discharge from ICU in comparison with patients who discharge from pathological or surgical department. The study was conducted on five major hospitals "ATTIKON", "THRIASSIO", "KAT", "GNA GENNIMATAS", "KORGIALENIO - BENAKIO". A standardized instrument was used especially for this study and is based on "ΜΙΝΙ: Mini International Neuropsychiatric Interview" and DSM-IV. The data collection was carried out through personal interviews with the patients. It is a cross-sectional study and also a case-control study. The sample of the research was composed of 198 patients, from whom 102 were in ICU (ICU group) and 96 were not (non-ICU group). The results of the statistical processing have shown that there is a positive and statistically significant correlation between MD-PTSD and hospitalization in ICU, and particular hospitalization in ICU increases the likelihood of developing MD by 1.94 times and PTSD by 3.48 times, compared to treatment in another part of the hospital. Furthermore, the ICU group was found to suffer more than the control group from MD (32.4% vs 19.8%) and PTSD (35,3% vs 13,5%). The investigation of sociodemographic characteristics showed that being a woman discharged from ICU is nearly five times more likely to develop MD and nearly twelve times more likely to develop PTSD compared with men. Old age in ICU acts as a protective factor from PTSD. Regarding the clinical

  19. Coping behavior and risk and resilience stress factors in French regional emergency medicine unit workers: a cross-sectional survey.

    Science.gov (United States)

    Lala, A I; Sturzu, L M; Picard, J P; Druot, F; Grama, F; Bobirnac, G

    2016-01-01

    The Emergency Department (ED) has the highest workload in a hospital, offering care to patients in their most acute state of illness, as well as comforting their families and tending to stressful situations of the physical and psychological areal. Method. A cross-sectional survey of 366 Emergency Unit staff members including medical doctors, medical residents, medical nurses and ward aids, was undergone. Study participants came from four periphery hospitals in the Moselle Department of Eastern France with similar workforce and daily patient loads statistics. The instruments used were the Perceived Stress Scale PSS-10 and the Brief COPE questionnaire. Conclusions. Perceived work overload and overall stress is strongly related to work hours and tend to have a stronger influence on doctors than on the nursing staff. Substance use is a common coping method for medical interns, consistent with prior research. The regular assessment of the ED staff perception of stress and stress related factors is essential to support organizational decisions in order to promote a better work environment and better patient care.

  20. Physician discretion is safe and may lower stress test utilization in emergency department chest pain unit patients.

    Science.gov (United States)

    Napoli, Anthony M; Arrighi, James A; Siket, Matthew S; Gibbs, Frantz J

    2012-03-01

    Chest pain unit (CPU) observation with defined stress utilization protocols is a common management option for low-risk emergency department patients. We sought to evaluate the safety of a joint emergency medicine and cardiology staffed CPU. Prospective observational trial of consecutive patients admitted to an emergency department CPU was conducted. A standard 6-hour observation protocol was followed by cardiology consultation and stress utilization largely at their discretion. Included patients were at low/intermediate risk by the American Heart Association, had nondiagnostic electrocardiograms, and a normal initial troponin. Excluded patients were those with an acute comorbidity, age >75, and a history of coronary artery disease, or had a coexistent problem restricting 24-hour observation. Primary outcome was 30-day major adverse cardiovascular events-defined as death, nonfatal acute myocardial infarction, revascularization, or out-of-hospital cardiac arrest. A total of 1063 patients were enrolled over 8 months. The mean age of the patients was 52.8 ± 11.8 years, and 51% (95% confidence interval [CI], 48-54) were female. The mean thrombolysis in myocardial infarction and Diamond & Forrester scores were 0.6% (95% CI, 0.51-0.62) and 33% (95% CI, 31-35), respectively. In all, 51% (95% CI, 48-54) received stress testing (52% nuclear stress, 39% stress echocardiogram, 5% exercise, 4% other). In all, 0.9% patients (n = 10, 95% CI, 0.4-1.5) were diagnosed with a non-ST elevation myocardial infarction and 2.2% (n = 23, 95% CI, 1.3-3) with acute coronary syndrome. There was 1 (95% CI, 0%-0.3%) case of a 30-day major adverse cardiovascular events. The 51% stress test utilization rate was less than the range reported in previous CPU studies (P < 0.05). Joint emergency medicine and cardiology management of patients within a CPU protocol is safe, efficacious, and may safely reduce stress testing rates.

  1. Remedial investigation work plan for Bear Creek Valley Operable Unit 2 (Rust Spoil Area, SY-200 Yard, Spoil Area 1) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Environmental Restoration Program

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    The enactment of the Resource Conservation and Recovery Act (RCRA) in 1976 and the Hazardous and Solid Waste Amendments (HSWA) to RCRA in 1984 created management requirements for hazardous waste facilities. The facilities within the Oak Ridge Reservation (ORR) were in the process of meeting the RCRA requirements when ORR was placed on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) on November 21, 1989. Under RCRA, the actions typically follow the RCRA Facility Assessment (RFA)/RCRA Facility Investigation (RFI)/Corrective Measures Study (CMS)/Corrective Measures implementation process. Under CERCLA the actions follow the PA/SI/Remedial Investigation (RI)/Feasibility Study (FS)/Remedial Design/Remedial Action process. The development of this document will incorporate requirements under both RCRA and CERCLA into an RI work plan for the characterization of Bear Creek Valley (BCV) Operable Unit (OU) 2.

  2. Remedial investigation report on Bear Creek Valley Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 1, Main text

    International Nuclear Information System (INIS)

    1994-08-01

    The enactment of the Resource Conservation and Recovery Act (RCRA) in 1976 and the Hazardous and Solid Waste Amendments (HSWA) to RCRA in 1984 created management requirements for hazardous waste facilities. The facilities within the Oak Ridge Reservation (ORR) were in the process of meeting the RCRA requirements when the ORR was placed on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) on November 21, 1989. Under RCRA, the actions typically follow the RCRA Facility Assessment/RCRA Facility Investigation (RFI)/Corrective Measures Study (CMS)/Corrective Measures Implementation process. Under CERCLA, the actions follow the preliminary assessment/site investigation/Remedial Investigation (RI)/Feasibility Study (FS)/Remedial Design/Remedial Action process. This document incorporates requirements under both RCRA and CERCLA in the form of an RI report for the characterization of Bear Creek Valley (BCV) Operable Unit (OU) 2

  3. Remedial investigation work plan for Bear Creek Valley Operable Unit 2 (Rust Spoil Area, SY-200 Yard, Spoil Area 1) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1993-05-01

    The enactment of the Resource Conservation and Recovery Act (RCRA) in 1976 and the Hazardous and Solid Waste Amendments (HSWA) to RCRA in 1984 created management requirements for hazardous waste facilities. The facilities within the Oak Ridge Reservation (ORR) were in the process of meeting the RCRA requirements when ORR was placed on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) on November 21, 1989. Under RCRA, the actions typically follow the RCRA Facility Assessment (RFA)/RCRA Facility Investigation (RFI)/Corrective Measures Study (CMS)/Corrective Measures implementation process. Under CERCLA the actions follow the PA/SI/Remedial Investigation (RI)/Feasibility Study (FS)/Remedial Design/Remedial Action process. The development of this document will incorporate requirements under both RCRA and CERCLA into an RI work plan for the characterization of Bear Creek Valley (BCV) Operable Unit (OU) 2

  4. Evaluation of Strip Footing Bearing Capacity Built on the Anthropogenic Embankment by Random Finite Element Method

    Science.gov (United States)

    Pieczynska-Kozlowska, Joanna

    2014-05-01

    One of a geotechnical problem in the area of Wroclaw is an anthropogenic embankment layer delaying to the depth of 4-5m, arising as a result of historical incidents. In such a case an assumption of bearing capacity of strip footing might be difficult. The standard solution is to use a deep foundation or foundation soil replacement. However both methods generate significant costs. In the present paper the authors focused their attention on the influence of anthropogenic embankment variability on bearing capacity. Soil parameters were defined on the basis of CPT test and modeled as 2D anisotropic random fields and the assumption of bearing capacity were made according deterministic finite element methods. Many repeated of the different realizations of random fields lead to stable expected value of bearing capacity. The algorithm used to estimate the bearing capacity of strip footing was the random finite element method (e.g. [1]). In traditional approach of bearing capacity the formula proposed by [2] is taken into account. qf = c'Nc + qNq + 0.5γBN- γ (1) where: qf is the ultimate bearing stress, cis the cohesion, qis the overburden load due to foundation embedment, γ is the soil unit weight, Bis the footing width, and Nc, Nq and Nγ are the bearing capacity factors. The method of evaluation the bearing capacity of strip footing based on finite element method incorporate five parameters: Young's modulus (E), Poisson's ratio (ν), dilation angle (ψ), cohesion (c), and friction angle (φ). In the present study E, ν and ψ are held constant while c and φ are randomized. Although the Young's modulus does not affect the bearing capacity it governs the initial elastic response of the soil. Plastic stress redistribution is accomplished using a viscoplastic algorithm merge with an elastic perfectly plastic (Mohr - Coulomb) failure criterion. In this paper a typical finite element mesh was assumed with 8-node elements consist in 50 columns and 20 rows. Footings width B

  5. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  6. Sub-surface Fatigue Crack Growth at Alumina Inclusions in AISI 52100 Roller Bearings

    DEFF Research Database (Denmark)

    Cerullo, Michele

    2014-01-01

    Sub-surface fatigue crack growth at non metallic inclusions is studied in AISI 52100 bearing steel under typical rolling contact loads. A first 2D plane strain finite element analysis is carried out to compute the stress history in the innner race at a characteristic depth, where the Dang Van...... damage factor is highest. Subsequently the stress history is imposed as boundary conditions in a periodic unit cell model, where an alumina inclusion is embedded in a AISI 52100 matrix. Cracks are assumed to grow radially from the inclusion under cyclic loading. The growth is predicted by means...

  7. Selected Abiotic and Biotic Environmental Stress Factors Affecting Two Economically Important Sugarcane Stalk Boring Pests in the United States

    Directory of Open Access Journals (Sweden)

    Allan T. Showler

    2016-02-01

    Full Text Available Sugarcane, Saccharum spp., in the United States is attacked by a number of different arthropod pests. The most serious among those pests are two stalk boring moths in the Family Crambidae: the sugarcane borer, Diatraea saccharalis (F., and the Mexican rice borer, Eoreuma loftini (Dyar. The two species are affected by abiotic and biotic environmental stress factors. Water deficit and excessive soil nitrogen alter physical and physiochemical aspects of the sugarcane plant that make the crop increasingly vulnerable to E. loftini. Weed growth can be competitive with sugarcane but it also supports enhanced abundances and diversity of natural enemies that can suppress infestations of D. saccharalis. In an instance where the stalk borer is considered a stress factor, proximity of vulnerable crops to sugarcane can influence levels of E. loftini infestation of sugarcane. The adverse effects of each stress factor, in terms of stalk borer attack, can be reduced by adopting appropriate cultural practices, such as adequate irrigation, judicious use of nitrogen fertilizer, using noncompetitive weed growth, and not planting vulnerable crops near sugarcane fields. Understanding the relationships between stress factors and crop pests can provide valuable insights for plant breeders and tools for incorporation into integrated pest management strategies.

  8. A Structural Finite Element Model for Lamellar Unit of Aortic Media Indicates Heterogeneous Stress Field After Collagen Recruitment

    Science.gov (United States)

    Thunes, James R.; Pal, Siladitya; Fortunato, Ronald N.; Phillippi, Julie A.; Gleason, Thomas G.; Vorp, David A.; Maiti, Spandan

    2016-01-01

    Incorporation of collagen structural information into the study of biomechanical behavior of ascending thoracic aortic (ATA) wall tissue should provide better insight into the pathophysiology of ATA. Structurally motivated constitutive models that include fiber dispersion and recruitment can successfully capture overall mechanical response of the arterial wall tissue. However, these models cannot examine local microarchitectural features of the collagen network, such as the effect of fiber disruptions and interaction between fibrous and non-fibrous components, which may influence emergent biomechanical properties of the tissue. Motivated by this need, we developed a finite element based three-dimensional structural model of the lamellar units of the ATA media that directly incorporates the collagen fiber microarchitecture. The fiber architecture was computer generated utilizing network features, namely fiber orientation distribution, intersection density and areal concentration, obtained from image analysis of multiphoton microscopy images taken from human aneurysmal ascending thoracic aortic media specimens with bicuspid aortic valve (BAV) phenotype. Our model reproduces the typical J-shaped constitutive response of the aortic wall tissue. We found that the stress state in the non-fibrous matrix was homogeneous until the collagen fibers were recruited, but became highly heterogeneous after that event. The degree of heterogeneity was dependent upon local network architecture with high stresses observed near disrupted fibers. The magnitude of non-fibrous matrix stress at higher stretch levels was negatively correlated with local fiber density. The localized stress concentrations, elucidated by this model, may be a factor in the degenerative changes in aneurysmal ATA tissue. PMID:27113538

  9. Is Less Noise, Light and Parental/Caregiver Stress in the Neonatal Intensive Care Unit Better for Neonates?

    Science.gov (United States)

    Venkataraman, Rohini; Kamaluddeen, Majeeda; Amin, Harish; Lodha, Abhay

    2018-01-15

    In utero sensory stimuli and interaction with the environment strongly influence early phases of fetal and infant development. Extremely premature infants are subjected to noxious procedures and routine monitoring, in addition to exposure to excessive light and noise, which disturb the natural sleep cycle and induce stress. Non-invasive ventilation, measures to prevent sepsis, and human milk feeding improve short-term and long-term neurodevelopmental outcomes in premature infants. To preserve brain function, and to improve quality of life and long-term neurodevelopmental outcomes, the focus now is on the neonatal intensive care unit (NICU) environment and its impact on the infant during hospital stay. The objectives of this write-up are to understand the effects of environmental factors, including lighting and noise in the NICU, on sensory development of the infant, the need to decrease parental and caregiver stress, and to review existing literature, local policies and recommendations.

  10. 40Ar/39Ar stratigraphy of pyroclastic units from the Cañadas Volcanic Edifice (Tenerife, Canary Islands) and their bearing on the structural evolution

    OpenAIRE

    Huertas Coronel, María José; Arnaud, N.; Ancochea Soto, Eumenio; Cantagrel, Jean Marie; Fúster Casas, José María

    2002-01-01

    Many felsic pyroclastic units of various types are exposed in different sectors of Tenerife. New 40Ar/39Ar determinations allow them to be placed more precisely in the general volcano-stratigraphic succession. According to geographic distribution, stratigraphic position and isotopic ages, four main pyroclastic phases may be identified. The first, San Juan de la Rambla phase (2.1 Ma), is only known in the north of Tenerife in the Tigaiga massif. The second, Adeje phase (1.8–1.5 Ma), is most co...

  11. Infants born preterm, stress, and neurodevelopment in the neonatal intensive care unit: might music have an impact?

    Science.gov (United States)

    Anderson, Dane E; Patel, Aniruddh D

    2018-03-01

    The neonatal intensive care unit (NICU) provides life-saving medical care for an increasing number of newborn infants each year. NICU care, while lifesaving, does have attendant consequences which can include repeated activation of the stress response and reduced maternal interaction, with possible negative long-term impacts on brain development. Here we present a neuroscientific framework for considering the impact of music on neurodevelopment in the NICU of infants born preterm and evaluate current literature on the use of music with this population to determine what is most reliably known of the physiological effects of music interventions. Using online academic databases we collected relevant, experimental studies aimed at determining effects of music listening in infants in the NICU. These articles were evaluated for methodological rigor, ranking the 10 most experimentally stringent as a representative sample. The selected literature seems to indicate that effects are present on the cardio-pulmonary system and behavior of neonates, although the relative effect size remains unclear. These findings indicate a need for more standardized longitudinal studies aimed at determining not only whether NICU music exposure has beneficial effects on the cardio-pulmonary system, but also on the hypothalamic-pituitary-adrenal axis, brain structures, and cognitive behavioral status of these children as well. Provides a neuroscience framework for considering how music might attenuate stress in neonatal intensive care unit (NICU) infants. Considers how repeated stress may cause negative neurodevelopmental impacts in infants born preterm. Posits epigenetics can serve as a mechanistic pathway for music moderating the stress response. © 2018 Mac Keith Press.

  12. 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....

  13. 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.

  14. Water stress projections for the northeastern and Midwestern United States in 2060: anthropogenic and ecological consequences

    Science.gov (United States)

    Brian G. Tavernia; Mark D. Nelson; Peter Caldwell; Ge Sun

    2013-01-01

    Future climate and land-use changes and growing human populations may reduce the abundance of water resources relative to anthropogenic and ecological needs in the Northeast and Midwest (U.S.). We used output from WaSSI, a water accounting model, to assess potential changes between 2010 and 2060 in (1) anthropogenic water stress for watersheds throughout the Northeast...

  15. Climatic stress increases forest fire severity across the western United States

    Science.gov (United States)

    Phillip J. van Mantgem; Jonathan C.B. Nesmith; MaryBeth Keifer; Eric E. Knapp; Alan Flint; Lorriane Flint

    2013-01-01

    Pervasive warming can lead to chronic stress on forest trees, which may contribute to mortality resulting from fire-caused injuries. Longitudinal analyses of forest plots from across the western US show that high pre-fire climatic water deficit was related to increased post-fire tree mortality probabilities. This relationship between climate and fire was present after...

  16. Comments to a polar bear population model

    OpenAIRE

    Øritsland, Nils Are

    1985-01-01

    Larsen, T. & Ugland, K. I. (Polar Research 2 n.s., 117-118) note correctly that a Leslie matrix model treats cubs and females as independent units which is not the case for polar bears. Population projections using the Leslie model with hunting mortalities added are instructive first approximations in evaluations of field data, however, and are recommended as exercises also for polar bear biologists. An APL programme for such projections is available.

  17. Thermal and stress analyses of the reactor pressure vessel lower head of the Three Mile Island Unit 2

    International Nuclear Information System (INIS)

    Hashimoto, K.; Onizawa, K.; Kurihara, R.; Kawasaki, S.; Soda, K.

    1992-01-01

    Thermal and stress analyses were performed using the finite element analysis code ABAQUS to clarify the factors which caused tears in the stainless steel liner of the reactor pressure vessel lower head of the Three Mile Island Unit 2 (TMI-2) reactor pressure vessel during the accident on 28 March 1979. The present analyses covered the events which occurred after approximately 20 tons of molten core material were relocated to the lower head of the reactor pressure vessel. They showed that the tensile stress was highest in the case where the relocated core material consisting of homogeneous UO 2 debris was assumed to attack the lower head and the debris was then quenched. The peak tensile stress was in the vicinity of the welded zone of the penetration nozzle. This result agrees with the findings from the examination of the TMI-2 reactor pressure vessel that major tears in the stainless steel liner were observed around two penetration nozzles of the lower head. (author)

  18. Nonlinear Dynamical Analysis for a Plain Bearing

    Directory of Open Access Journals (Sweden)

    Ali Belhamra

    2014-03-01

    Full Text Available This paper investigates the nonlinear dynamic behavior for a plain classic bearing (fluid bearing lubricated by a non-Newtonian fluid of a turbo machine rotating with high speed; this type of fluid contains additives viscosity (couple-stress fluid film. The solution of the nonlinear dynamic problem of this type of bearing is determined with a spatial discretisation of the modified Reynolds' equation written in dynamic mode by using the optimized short bearing theory and a temporal discretisation for equations of rotor motion by the help of Euler's explicit diagram. This study analyzes the dynamic behavior of a rotor supported by two couple-stress fluid film journal lubricant enhances the dynamic stability of the rotor-bearing system considerably compared to that obtained when using a traditional Newtonian lubricant. The analysis shows that the dynamic behavior of a shaft which turns with high velocities is strongly nonlinear even for poor eccentricities of unbalance; the presence of parameters of couple stress allows strongly attenuating the will synchrony (unbalance and asynchrony (whipping amplitudes of vibrations of the shaft which supports more severe conditions (large unbalances.

  19. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  20. Impacts of multiple stresses on water demand and supply across the southeastern United States

    Science.gov (United States)

    Ge Sun; Steven G. McNulty; Jennifer A. Moore Myers; Erika C. Cohen

    2008-01-01

    Assessment of long-term impacts of projected changes in climate, population, and land use and land cover on regional water resource is critical to the sustainable development of the southeastern United States. The objective of this study was to fully budget annual water availability for water supply (precipitation ) evapotranspiration + groundwater supply + return flow...

  1. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  2. Bearing restoration by grinding

    Science.gov (United States)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  3. Plotting and Determination of Nominal Stresses in the Сrankshaft Components of V Configuration Engine with Offset Rod Bearing Journals

    Directory of Open Access Journals (Sweden)

    M. Yu. Mikhailov

    2017-01-01

    Full Text Available Currently, a great number of large vehicle engines, especially diesel ones, have a V-shaped configuration layout. For six-cylinder and eight-cylinder V-engines, to simplify a processing technology of the block-crankcases, in the section manufacturers often use the 90° angle, which is the most prevalent angle for the V8 engine. However, in this case, an even firing cycle in the cylinders is not provided for the V6 layout. This leads to significant vibrations, especially at idle and requires for a more massive flywheel.Designers face the challenge to provide the even firing cycle in the cylinders. To solve this problem are often used the crankshaft designs, which have the offset rod journals. However, it leads to the manufacturing complexity of the shaft, and also to the need to use the special methods of calculation.There are no direct calculation methods for the crankshafts of this design. The paper proposes a technique to define the nominal stresses in the crankshaft of this design. To consider the shaft is used a split-type design. The paper presents a schematic diagram of the crankshaft loading, and on its basis describes equations of the moments for each section. A special attention is drawn to the new constructive element, i.e. an intermediate cheek. For clarity, the diagrams of moments in two mutually perpendicular planes are built. It is worth noting that the paper also proposes a technique from transition from the global to the local coordinate system when considering the moments in the crankshaft elements.Further, there are the appropriate expressions to determine the nominal stresses. This is one of the main desired values in calculating the crankshaft endurance. The developed technique in the particular case allows the calculation of crankshaft engine models that can be subsumed under the advantages.In the future the proposed technique is expected to be a basis for creating a software complex. The complex objective is expected to be

  4. High-performance plain bearings for diesel engines. Hochleistungs-Gleitlager fuer Dieselmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, R.M.; Mathias, M.; Herrmann, B. (MTU, Friedrichshafen (Germany))

    1992-01-01

    The crankshaft bearings are among the most highly stressed engine components. Conventional plain bearings no longer fulfill the requirements of modern high-performance diesel engines. Introduction of the 'Sputter' technology, as a method of anti friction layer application, opened new perspectives in the field of plain bearing manufacture. In this presentation it is intended to compare various types of plain bearings and to demonstrate operation-oriented bearing testing. (orig.).

  5. 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.

  6. Grizzly bear corticosteroid binding globulin: Cloning and serum protein expression.

    Science.gov (United States)

    Chow, Brian A; Hamilton, Jason; Alsop, Derek; Cattet, Marc R L; Stenhouse, Gordon; Vijayan, Mathilakath M

    2010-06-01

    Serum corticosteroid levels are routinely measured as markers of stress in wild animals. However, corticosteroid levels rise rapidly in response to the acute stress of capture and restraint for sampling, limiting its use as an indicator of chronic stress. We hypothesized that serum corticosteroid binding globulin (CBG), the primary transport protein for corticosteroids in circulation, may be a better marker of the stress status prior to capture in grizzly bears (Ursus arctos). To test this, a full-length CBG cDNA was cloned and sequenced from grizzly bear testis and polyclonal antibodies were generated for detection of this protein in bear sera. The deduced nucleotide and protein sequences were 1218 bp and 405 amino acids, respectively. Multiple sequence alignments showed that grizzly bear CBG (gbCBG) was 90% and 83% identical to the dog CBG nucleotide and amino acid sequences, respectively. The affinity purified rabbit gbCBG antiserum detected grizzly bear but not human CBG. There were no sex differences in serum total cortisol concentration, while CBG expression was significantly higher in adult females compared to males. Serum cortisol levels were significantly higher in bears captured by leg-hold snare compared to those captured by remote drug delivery from helicopter. However, serum CBG expression between these two groups did not differ significantly. Overall, serum CBG levels may be a better marker of chronic stress, especially because this protein is not modulated by the stress of capture and restraint in grizzly bears. Copyright 2010 Elsevier Inc. All rights reserved.

  7. Association of work-related stress with mental health problems in a special police force unit.

    Science.gov (United States)

    Garbarino, Sergio; Cuomo, Giovanni; Chiorri, Carlo; Magnavita, Nicola

    2013-01-01

    Law and order enforcement tasks may expose special force police officers to significant psychosocial risk factors. The aim of this work is to investigate the relationship between job stress and the presence of mental health symptoms while controlling sociodemographical, occupational and personality variables in special force police officers. At different time points, 292 of 294 members of the 'VI Reparto Mobile', a special police force engaged exclusively in the enforcement of law and order, responded to our invitation to complete questionnaires for the assessment of personality traits, work-related stress (using the Demand-Control-Support (DCS) and the Effort-Reward-Imbalance (ERI) models) and mental health problems such as depression, anxiety and burnout. Regression analyses showed that lower levels of support and reward and higher levels of effort and overcommitment were associated with higher levels of mental health symptoms. Psychological screening revealed 21 (7.3%) likely cases of mild depression (Beck Depression Inventory, BDI≥10). Officers who had experienced a discrepancy between work effort and rewards showed a marked increase in the risk of depression (OR 7.89, 95% CI 2.32 to 26.82) when compared with their counterparts who did not perceive themselves to be in a condition of distress. The findings of this study suggest that work-related stress may play a role in the development of mental health problems in police officers. The prevalence of mental health symptoms in the cohort investigated here was low, but not negligible in the case of depression. Since special forces police officers have to perform sensitive tasks for which a healthy psychological functioning is needed, the results of this study suggest that steps should be taken to prevent distress and improve the mental well-being of these workers.

  8. Investigation of intergranular stress corrosion cracking in the fuel pool at Three Mile Island Unit 1

    International Nuclear Information System (INIS)

    Czajkowski, C.J.

    1985-01-01

    An intergranular stress corrosion cracking failure of 304 stainless steel pipe in 2000 ppM B as H 3 BO 3 + H 2 O at 100 0 C has been investigated. Constant extension rate testing has produced an intergranular type failure in material in air. Chemical analysis was performed on both the base metal and weld material, in addition to fractography, EPR testing and optical microscopy in discerning the mode of failure. Various effects of Cl - , O 2 , and MnS are discussed. The results have indicated that the cause of failure was the severe sensitization coupled with probable contamination by S and possibly by Cl ions

  9. Filipino nurses in the United States: recruitment, retention, occupational stress, and job satisfaction.

    Science.gov (United States)

    Hayne, Arlene N; Gerhardt, Clara; Davis, Jonathan

    2009-07-01

    Solutions to the nursing shortage in North America include the recruitment of international nurses. This descriptive study examines strategies to facilitate the cultural adaptation, job satisfaction, and perception of role and social support of a group of recruited Filipino nurses. Instruments used were the Nursing Work Index-Revised Edition and Occupation Stress Inventory-Revised Edition. Results indicated that the investment in promoting the well-being of recruits in both social and work contexts positively benefits job satisfaction and spills over into related areas of satisfaction and positive adaptation. The literature study also focuses on areas of cultural competence in the context of transcultural nursing.

  10. Climatic stress increases forest fire severity across the western United States

    Science.gov (United States)

    van Mantgem, Philip J.; Nesmith, Jonathan C. B.; Keifer, MaryBeth; Knapp, Eric E.; Flint, Alan; Flint, Lorriane

    2013-01-01

    Pervasive warming can lead to chronic stress on forest trees, which may contribute to mortality resulting from fire-caused injuries. Longitudinal analyses of forest plots from across the western US show that high pre-fire climatic water deficit was related to increased post-fire tree mortality probabilities. This relationship between climate and fire was present after accounting for fire defences and injuries, and appeared to influence the effects of crown and stem injuries. Climate and fire interactions did not vary substantially across geographical regions, major genera and tree sizes. Our findings support recent physiological evidence showing that both drought and heating from fire can impair xylem conductivity. Warming trends have been linked to increasing probabilities of severe fire weather and fire spread; our results suggest that warming may also increase forest fire severity (the number of trees killed) independent of fire intensity (the amount of heat released during a fire).

  11. A tailored relocation stress intervention programme for family caregivers of patients transferred from a surgical intensive care unit to a general ward.

    Science.gov (United States)

    Lee, Seul; Oh, HyunSoo; Suh, YeonOk; Seo, WhaSook

    2017-03-01

    To develop and examine a relocation stress intervention programme tailored for the family caregivers of patients scheduled for transfer from a surgical intensive care unit to a general ward. Family relocation stress syndrome has been reported to be similar to that exhibited by patients, and investigators have emphasised that nurses should make special efforts to relieve family relocation stress to maximise positive contributions to the well-being of patients by family caregivers. A nonequivalent control group, nonsynchronised pretest-post-test design was adopted. The study subjects were 60 family caregivers of patients with neurosurgical or general surgical conditions in the surgical intensive care unit of a university hospital located in Incheon, South Korea. Relocation stress and family burden were evaluated at three times, that is before intervention, immediately after transfer and four to five days after transfer. This relocation stress intervention programme was developed for the family caregivers based on disease characteristics and relocation-related needs. In the experimental group, relocation stress levels significantly and continuously decreased after intervention, whereas in the control group, a slight nonsignificant trend was observed. Family burden levels in the control group increased significantly after transfer, whereas burden levels in the experimental group increased only marginally and nonsignificantly. No significant between-group differences in relocation stress or family burden levels were observed after intervention. Relocation stress levels of family caregivers were significantly decreased after intervention in the experimental group, which indicates that the devised family relocation stress intervention programme effectively alleviated family relocation stress. The devised intervention programme, which was tailored to disease characteristics and relocation-related needs, may enhance the practicality and efficacy of relocation stress

  12. Hydrostatic radial bearing of centrifugal pump

    International Nuclear Information System (INIS)

    Skalicky, A.

    1976-01-01

    A hydrostatic radial pump is described characterized by the fact that part of the medium off-taken from delivery is used as a lubricating medium. Two additional bodies are placed alongside a hydrostatic bearing with coils in between them and the pump shaft; the coils have an opposite pitch. The feed channel for the hydrostatic bearing pocket is linked to delivery. The coil outlets are connected to the pump suction unit. Two rotating coils placed alongside the hydrostatic bearing will considerably simplify the communication channel design and reduce the dependence on the pump shaft deflections. The addition of another rotating coil in the close vicinity of the pump shaft or directly on the shaft further increases the efficiency. The bearing can be used in designing vertical circulating pumps for the cooling circuits of nuclear reactors. (J.B.)

  13. Superconducting Meissner effect bearings for cryogenic turbomachines, phase 2

    Science.gov (United States)

    Valenzuela, Javier A.; Martin, Jerry L.

    1994-02-01

    This is the final report of a Phase 2 SBIR project to develop Meissner effect bearings for miniature cryogenic turbomachines. The bearing system was designed for use in miniature cryogenic turboexpanders in reverse-Brayton-cycle cryocoolers. The cryocoolers are designed to cool sensors on satellites. Existing gas bearings for this application run in a relatively warm state. The heat loss from the bearings into the shaft and into the cold process gas imposes a penalty on the cycle efficiency. By using cold Meissner effect bearings, this heat loss could be minimized, and the input power per unit of cooling for these cryocoolers could be reduced. Two bearing concepts were explored in this project. The first used an all-magnetic passive radial suspension to position the shaft over a range of temperatures from room temperature to 77 K. This bearing concept was proven to be feasible, but impractical for the miniature high-speed turbine application since it lacked the required shaft positioning accuracy. A second bearing concept was then developed. In this concept, the Meissner effect bearings are combined with self-acting gas bearings. The Meissner effect bearing provides the additional stiffness and damping required to stabilize the shaft at low temperature, while the gas bearing provides the necessary accuracy to allow very small turbine tip clearances (5mm) and high speeds (greater than 500,000 rpm).

  14. Early transfer of mated females into the maternity unit reduces stress and increases maternal care in farm mink

    DEFF Research Database (Denmark)

    Malmkvist, Jens; Palme, Rupert

    2015-01-01

    Mated mammals on farms are typically transferred to another housing environment prior to delivery. We investigated whether the timing of this transfer – EARLY (Day −36), INTERMEDIATE (Day −18), or LATE (Day −3) relative to the expected day of birth (Day 0) – affects maternal stress, maternal care...... sized groups (n = 60): (i) ‘EARLY’, transfer to maternity unit immediately after the end of the mating period, March 23; (ii) ‘INTERMEDIATE’, transfer in the middle of the period, April 10; (iii) ‘LATE’, transfer late in the pregnancy period, April 25. Data collection included weekly determination...... of faecal cortisol metabolites (FCM) and evaluation of maternal care: nest building, in-nest temperature, plus kit-retrieval behaviour, kit mortality and growth day 0–7 postpartum. We document that mated mink females build and maintain a nest at least 1 month prior to delivery when transferred...

  15. Integral finite element analysis of turntable bearing with flexible rings

    Science.gov (United States)

    Deng, Biao; Liu, Yunfei; Guo, Yuan; Tang, Shengjin; Su, Wenbin; Lei, Zhufeng; Wang, Pengcheng

    2018-03-01

    This paper suggests a method to calculate the internal load distribution and contact stress of the thrust angular contact ball turntable bearing by FEA. The influence of the stiffness of the bearing structure and the plastic deformation of contact area on the internal load distribution and contact stress of the bearing is considered. In this method, the load-deformation relationship of the rolling elements is determined by the finite element contact analysis of a single rolling element and the raceway. Based on this, the nonlinear contact between the rolling elements and the inner and outer ring raceways is same as a nonlinear compression spring and bearing integral finite element analysis model including support structure was established. The effects of structural deformation and plastic deformation on the built-in stress distribution of slewing bearing are investigated on basis of comparing the consequences of load distribution, inner and outer ring stress, contact stress and other finite element analysis results with the traditional bearing theory, which has guiding function for improving the design of slewing bearing.

  16. Gearbox Reliability Collaborative Investigation of High-Speed-Shaft Bearing Loads

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-06-01

    The loads and contact stresses in the bearings of the high speed shaft section of the Gearbox Reliability Collaborative gearbox are examined in this paper. The loads were measured though strain gauges installed on the bearing outer races during dynamometer testing of the gearbox. Loads and stresses were also predicted with a simple analytical model and higher-fidelity commercial models. The experimental data compared favorably to each model, and bearing stresses were below thresholds for contact fatigue and axial cracking.

  17. An analysis of post-traumatic stress symptoms in United States Air Force drone operators.

    Science.gov (United States)

    Chappelle, Wayne; Goodman, Tanya; Reardon, Laura; Thompson, William

    2014-06-01

    Remotely piloted aircraft (RPA), commonly referred to as "drones," have emerged over the past decade as an innovative warfighting tool. Given there is a paucity of empirical research assessing drone operators, the purpose of this study was to assess for the prevalence of PTSD symptoms among this cohort. Of the 1084 United States Air Force (USAF) drone operators that participated, a total of 4.3% endorsed a pattern of symptoms of moderate to extreme level of severity meeting criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders-4th edition. The incidence of PTSD among USAF drone operators in this study was lower than rates of PTSD (10-18%) among military personnel returning from deployment but higher than incidence rates (less than 1%) of USAF drone operators reported in electronic medical records. Although low PTSD rates may be promising, limitations to this study are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Onset of posttraumatic stress disorder and major depression among refugees and voluntary migrants to the United States.

    Science.gov (United States)

    Rasmussen, Andrew; Crager, Mia; Baser, Ray E; Chu, Tracy; Gany, Francesca

    2012-12-01

    Although refugees are generally thought to be at increased risk for posttraumatic stress disorder (PTSD) and major depressive episode (MDE), few studies have compared onset of PTSD and MDE between refugees and voluntary migrants. Given differences in migration histories, onset should differ pre- and postmigration. The National Latino and Asian American Survey (NLAAS) is a national representative, complex dataset measuring psychiatric morbidity, mental health service use, and migration history among Latino and Asian immigrants to the United States. Of the 3,260 foreign-born participants, 660 were refugees (a weighted proportion of 9.52%). Refugees were more likely to report a history of war-related trauma, but reports of other traumatic events were similar. Premigration onset of PTSD was statistically higher for refugees than voluntary migrants, odds ratio (OR) = 4.86, 95% confidence interval (CI) [2.01, 11.76], where postmigration onset for PTSD was not, OR = 0.61, 95% CI [0.29, 1.28]; a similar pattern was found for MDE, OR = 1.98, 95% CI [1.11, 3.51]; and OR = 1.02, 95% CI [0.65, 1.62], respectively. Although refugees arrive in host countries with more pressing psychiatric needs, onset is comparable over time, suggesting that postmigration refugees and voluntary migrants may be best served by similar programs. Copyright © 2012 International Society for Traumatic Stress Studies.

  19. Maximising methane production in stressed fermentation systems for swine production units

    Energy Technology Data Exchange (ETDEWEB)

    Hill, D T

    1984-01-01

    For economic reasons, digestion systems must be designed to allow the most compact plant. This forces heavy organic loading and relatively short detention times. Consequently, the digestion system is operating in the region approaching instability. An investigation into the effects on methane productivity of the method used to load anaerobic digesters has shown that when operating in regions approaching stress the method of loading plays a major role in maximising energy output. Since the digestion system is designed for steady-state loading, while the actual operating conditions are dynamic, the loading of the system actually varies greatly and is never at steady state. In loading the digestion system, two methods are available. Either Volatile Solids (VS) loading concentration will vary and loading volume remain constant or loading volume will vary and VS loading concentration remain constant. The choice of which operational method is used in a digestion system already operating under heavy loading greatly affects methane productivity. The internal energy usage of the plant also is affected. Results indicate that gross methane production is approximately 33% higher and VS reduction is increased by 28% for the fermentation plant operating with a varying detention time when compared to operating the same plant with a varying loading concentration. (Refs. 14).

  20. Risk factors for the development of post-traumatic stress disorder and coping strategies in mothers and fathers following infant hospitalisation in the neonatal intensive care unit.

    Science.gov (United States)

    Aftyka, Anna; Rybojad, Beata; Rosa, Wojciech; Wróbel, Aleksandra; Karakuła-Juchnowicz, Hanna

    2017-12-01

    The aim of this study was to identify the potential risk factors for the development of post-traumatic stress disorder in mothers and fathers following infant hospitalisation in the neonatal intensive care unit. The development of neonatal intensive care units has increased the survival rate of infants. However, one of the major parental problems is post-traumatic stress disorder. An observational study covered 125 parents (72 mothers and 53 fathers) of infants aged 3-12 months who were hospitalised in the neonatal intensive care unit during the neonatal period. Third-referral neonatal intensive care unit. Several standardised and self-reported research tools were used to estimate the level of post-traumatic stress symptoms (Impact Event Scale-Revised), perceived stress (Perceived Stress Scale) and coping strategies (COPE Inventory). The respondents also completed a Parent and Infant Characteristic Questionnaire. The mothers and fathers did not differ in their parental and infant characteristics. Post-traumatic stress disorder was present in 60% of the mothers and 47% of the fathers. Compared to the fathers, the mothers felt greater stress (p = .020) and presented a higher severity of post-traumatic stress disorder (p stress disorder in the mothers. In the fathers, an Apgar test at 1 min after birth (p = .030) and a partner's post-traumatic stress disorder (p = .038) were related to post-traumatic stress disorder. The mothers compared to the fathers were more likely to use strategies such as: positive reinterpretation and growth, focusing on and venting of emotions, instrumental social support, religious coping and acceptance. In the fathers, the predictors included an Apgar score at 1 min after birth, a lack of congenital anomalies in the child and mental disengagement. Risk factors for post-traumatic stress disorder, as well as coping strategies, differ in women compare to men. Knowledge of risk factors for post-traumatic stress disorder, specific to

  1. 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.

  2. Ultra-precision bearings

    CERN Document Server

    Wardle, F

    2015-01-01

    Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

  3. Operational Stress Control and Readiness (OSCAR): The United States Marine Corps Initiative to Deliver Mental Health Services to Operating Forces

    National Research Council Canada - National Science Library

    Nash, William P

    2006-01-01

    Combat/operational stress control, defined as programs and policies to prevent, identify, and manage adverse combat/operational stress reactions, is the primary responsibility of military commanders...

  4. Sugar maple growth in relation to nutrition and stress in the northeastern United States.

    Science.gov (United States)

    Long, Robert P; Horsley, Stephen B; Hallett, Richard A; Bailey, Scott W

    2009-09-01

    Sugar maple, Acer saccharum, decline disease is incited by multiple disturbance factors when imbalanced calcium (Ca), magnesium (Mg), and manganese (Mn) act as predisposing stressors. Our objective in this study was to determine whether factors affecting sugar maple health also affect growth as estimated by basal area increment (BAI). We used 76 northern hardwood stands in northern Pennsylvania, New York, Vermont, and New Hampshire, USA, and found that sugar maple growth was positively related to foliar concentrations of Ca and Mg and stand level estimates of sugar maple crown health during a high stress period from 1987 to 1996. Foliar nutrient threshold values for Ca, Mg, and Mn were used to analyze long-term BAI trends from 1937 to 1996. Significant (P maples sampled in the 1990s had decreased growth in the 1970s, 10-20 years in advance of the 1980s and 1990s decline episode in Pennsylvania. Even apparently healthy stands that had no defoliation, but had below-threshold amounts of Ca or Mg and above-threshold Mn (from foliage samples taken in the mid 1990s), had decreasing growth by the 1970s. Co-occurring black cherry, Prunus serotina, in a subset of the Pennsylvania and New York stands, showed opposite growth responses with greater growth in stands with below-threshold Ca and Mg compared with above-threshold stands. Sugar maple growing on sites with the highest concentrations of foliar Ca and Mg show a general increase in growth from 1937 to 1996 while other stands with lower Ca and Mg concentrations show a stable or decreasing growth trend. We conclude that acid deposition induced changes in soil nutrient status that crossed a threshold necessary to sustain sugar maple growth during the 1970s on some sites. While nutrition of these elements has not been considered in forest management decisions, our research shows species specific responses to Ca and Mg that may reduce health and growth of sugar maple or change species composition, if not addressed.

  5. DW_BEAR

    Data.gov (United States)

    Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

  6. Rolling bearing analysis

    CERN Document Server

    Harris, Tedric A

    2001-01-01

    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  7. Gear bearing drive

    Science.gov (United States)

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

    2011-01-01

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

  8. Applicability of 1994-1995 USRADS reg-sign surveys of Bear Creek Valley flood plain and Operable Unit 1 to the radiological characterization of Y-12 grassy/wooded areas

    International Nuclear Information System (INIS)

    Bogard, J.S.; Hamm, R.N.; Brown, K.S.

    1997-03-01

    This document, provided in support of the Y-12 Site Radiological Characterization Study, analyzes the utility of data from two reports by Chemrad Tennessee Corporation in identifying radiological contamination in excess of contamination control guidelines at the surface of soils in the Bear Creek Valley Flood Plain (BCVFP) and in Y-12 Operable Unit 1 (OU1). The Chemrad reports were developed under subcontract to Science Applications International Corporation for their remedial investigation of these sites for Martin Marietta Energy Systems Environmental Restoration Division. Surveys were performed by Chemrad using the UltraSonic Ranging and Data System (USRADS reg-sign), which utilizes ultrasonic triangulation to determine the location of a survey technician at the same time that radiological monitoring data are telemetered from his instruments to a remote receiving station. Floor monitor and Geiger-Mueller pancake meter results from the USRADS reg-sign surveys are shown to be sufficiently precise to reliably detect contamination in excess of the limiting radioactivity value of 1,000 dpm/100 cm 2 for removable uranium contamination specified in 10 CFR 835 Appendix D. MicroRem meter survey results, also included as part of the USRADS reg-sign surveys, indicate that the derived limiting value of 56.8 μrem/h for penetrating dose at 1 m (corresponding to 100 mrem/γ) was not exceeded. However, both the pancake meter and floor monitor results suggest that surface contamination exceeding 1,000 dpm/100 cm 2 is not uncommon. Sites in OU1 and BCVFP were visited, and independent surveys made with hand-held instruments, to confirm conclusions about the USRADS close-quote survey results and to verify that these results are from contamination uniformly distributed on the soil surface, and not from discrete sources which are not likely transferred to shoes, vehicles, or clothing

  9. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  10. The R and D D's bearing test benches

    International Nuclear Information System (INIS)

    Vialettes, J.M.

    1997-01-01

    In power generation plants, rotating machines are involved in energy transformation processes and safety systems. The bearings supporting the rotors and the thrust bearings play a crucial role in the reliability of these machines. The phenomena encountered straddle several disciplines: hydrodynamics, tribology, thermomechanics, materials and vibrations in a specific environment, namely: thin fluid film, solid mechanical components and shaft rotation. Means of analysing the behaviour of these components (bearings and thrust bearings) have been developed and implemented. These consists of the EDYOS (Etude Dynamique des Organes de Supportage) code for dynamically studying bearing devices and several related bench tests. In reality, in order to understand the complex physical phenomena encountered in these components, it is vital to carry out analyses and experimental validations. Since these investigations cannot be carried out on actual machines, test benches have been built which can subject the sample bearings to the equivalent stresses. (author)

  11. Occupational stress and mental health among nurses in a medical intensive care unit of a general hospital in Bandar Abbas in 2013.

    Science.gov (United States)

    Tajvar, Abdolhamid; Saraji, Gebraeil Nasl; Ghanbarnejad, Amin; Omidi, Leila; Hosseini, Seyed Sodabeh Seyed; Abadi, Ali Salehi Sahl

    2015-07-01

    Many nurses have reported experiencing high levels of occupational stress in their work environment. Stress, as an outcome of stressful workplaces and tasks, affects nursing behavior in hospital wards. The objectives of this research were to determine the prevalence of occupational stress and mental health problems in nurses in the intensive care unit (ICU) at Shahid Mohammadi Hospital in Bandar Abbas in 2013 and to determine the relationship between occupational stress and mental health. This cross-sectional study was conducted in 2013 on all of the nurses working in ICU at Shahid Mohammadi Hospital located in Bandar Abbas, Iran. Seventy-two nurses were selected as the population for this study, and all of them were female. Two questionnaires were used in this study, i.e., General Health Questionnaire-28 (GHQ-28) for assessing mental health and an occupational stress test for assessing job stress. Furthermore, the relationship between occupational stress and mental health was examined. One-way analysis of variance (ANOVA), independent samples t-test, and Pearson's product-moment correlation test were used to analyze the data. High and moderate levels of occupational stress were experienced by 83.9% and 10.7% of ICU nurses, respectively. The prevalence of mental disorders, somatic symptoms, anxiety, social dysfunction, and depression were 58.9, 60.7, 62.5, 71.4, and 10.7%, respectively. The findings of the independent samples t-test showed that somatic symptoms had significant relationships with age and working experience (p = 0.01). According to the independent samples t-test, there were no significant differences between somatic symptoms and working different shifts (p > 0.05). There was a high prevalence of occupational stress among ICU nurses. There was a significant relationship between occupational stress and mental health. Future interventions are needed to codify a comprehensive health program in this field to reduce occupational stress and enhance nurses

  12. Hydrostatic bearing with a stepped duct

    International Nuclear Information System (INIS)

    Krevsun, Eh.P.; Ivanov, A.A.

    1975-01-01

    A method for calculating and experimental data from tests on a hydrostatic bearing whose operating hydraulic channel is formed by two cylincrical surfaces, are presented. Unlike currently used hydrostatic bearings, the bearing described has no capillary choke or diaphragm choke at the entrance. This simplifies the construction and increases the reliability, especially when it is operated with corrosive liquids or liquids containing solid suspensoids and causing erosion and blockage of the choke structures. In order to obtain the calculated relations, the flow of a liquid from the bearing in the axial direction to one side through a part of an aperture of unit width was examined. The effect of rotating the axle, of flow in the circumferential direction, and curvature of the aperture was not considered. Isothermal and laminar flows were considered. Because of the simplicity of the hydraulic circuit and the satisfactory properties (bearing capability and flow rate), the bearing described may be used in pumps operating with corrosive liquids, with those containing solid suspensoids and in nuclear energy establishments. (author)

  13. Foothills model forest grizzly bear study : project update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-01-01

    This report updates a five year study launched in 1999 to ensure the continued healthy existence of grizzly bears in west-central Alberta by integrating their needs into land management decisions. The objective was to gather better information and to develop computer-based maps and models regarding grizzly bear migration, habitat use and response to human activities. The study area covers 9,700 square km in west-central Alberta where 66 to 147 grizzly bears exist. During the first 3 field seasons, researchers captured and radio collared 60 bears. Researchers at the University of Calgary used remote sensing tools and satellite images to develop grizzly bear habitat maps. Collaborators at the University of Washington used trained dogs to find bear scat which was analyzed for DNA, stress levels and reproductive hormones. Resource Selection Function models are being developed by researchers at the University of Alberta to identify bear locations and to see how habitat is influenced by vegetation cover and oil, gas, forestry and mining activities. The health of the bears is being studied by researchers at the University of Saskatchewan and the Canadian Cooperative Wildlife Health Centre. The study has already advanced the scientific knowledge of grizzly bear behaviour. Preliminary results indicate that grizzlies continue to find mates, reproduce and gain weight and establish dens. These are all good indicators of a healthy population. Most bear deaths have been related to poaching. The study will continue for another two years. 1 fig.

  14. Surfing USA: How Internet Use Prior to and during Study Abroad Affects Chinese Students' Stress, Integration, and Cultural Learning While in the United States

    Science.gov (United States)

    Mikal, Jude P.; Yang, Junhong; Lewis, Amy

    2015-01-01

    Campuses across the United States continue to welcome a record number of Chinese students coming in pursuit of both academic and cultural goals. Yet, high levels of acculturative stress coupled with difficulties integrating into life abroad jeopardize accomplishing these goals. In this study, we examine Chinese students' Internet use both prior to…

  15. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  16. Watchable Wildlife: The Black Bear

    Science.gov (United States)

    Lynn L. Rogers

    1992-01-01

    Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

  17. Gearbox Reliability Collaborative Gearbox 3 Planet Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-03-24

    The Gearbox Reliability Collaborative gearbox was redesigned to improve its load-sharing characteristics and predicted fatigue life. The most important aspect of the redesign was to replace the cylindrical roller bearings with preloaded tapered roller bearings in the planetary section. Similar to previous work, the strain gages installed on the planet tapered roller bearings were calibrated in a load frame. This report describes the calibration tests and provides the factors necessary to convert the measured units from dynamometer testing to bearing loads, suitable for comparison to engineering models.

  18. Tribology of alternative bearings.

    Science.gov (United States)

    Fisher, John; Jin, Zhongmin; Tipper, Joanne; Stone, Martin; Ingham, Eileen

    2006-12-01

    The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

  19. 76 FR 77981 - Build-A-Bear Workshop, Inc., Provisional Acceptance of a Settlement Agreement and Order

    Science.gov (United States)

    2011-12-15

    ... CONSUMER PRODUCT SAFETY COMMISSION [CPSC Docket No. 12-C0004] Build-A-Bear Workshop, Inc... 1118.20(e). Published below is a provisionally-accepted Settlement Agreement with Build-A-Bear Workshop..., Build-A-Bear Workshop, Inc. (``Build-A-Bear'') and staff of the United States Consumer Product Safety...

  20. Development of new layer systems for sliding bearings under high mechanical and tribological stress. Final report; Entwicklung neuer Schichtsysteme fuer den Einsatz bei mechanisch-tribologisch hochbeanspruchten Gleitlagern. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, M.; Herrmann, B.

    1995-12-31

    The report describes the sputtering technique as a coating method for sliding bearings of high-speed diesel engines. The project aimed at the development of a heavy-duty, wear-resistant sputtered layer on a copper-lead basis for sliding bearings. (HW) [Deutsch] Es wird berichtet ueber die Einfuehrung der Sputtertechnik als Beschichtungsverfahren fuer Gleitlager fuer schnell laufende Dieselmotoren. Ziel des Projektes war die Entwicklung einer hochbelastbaren, verschleissfesten Gleitlager-Sputterschicht auf Kupfer-Blei-Basis. (HW)

  1. A Three-Dimensional Foil Bearing Performance Map Applied to Oil-Free Turbomachinery

    Science.gov (United States)

    2009-04-01

    stress brought on by excessive viscous power loss; therefore a map that graphically relates component and system-level parameters (bearing size, applied...Introduction Foil bearings are self-acting, hydrodynamic gas bearings that use air as their working fluid . Their use in rotating systems eliminates the...weight, maintenance requirements, speed, and temperature limitations associated with conventional oil-lubricated rotor supports (i.e., bearings, dampers

  2. Partial tooth gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  3. Interference-Fit Life Factors for Ball Bearings

    Science.gov (United States)

    Oswald, Fred B.; Zaretsky, Erwin V.; Poplawski, Joseph V.

    2010-01-01

    The effect of hoop stresses on the rolling-element fatigue life of angular-contact and deep-groove ball bearings was determined for common inner-ring interference fits at the ABEC-5 tolerance level. The analysis was applied to over 1150 bearing configurations and load cases. Hoop stresses were superimposed on the Hertzian principal stresses created by the applied bearing load to calculate the inner-race maximum shearing stress. The resulting fatigue life of the bearing was recalculated through a series of equations. The reduction in the fatigue life is presented as life factors that are applied to the unfactored bearing life. The life factors found in this study ranged from 1.00 (no life reduction)--where there was no net interface pressure--to a worst case of 0.38 (a 62-percent life reduction). For a given interference fit, the reduction in life is different for angular-contact and deep-groove ball bearings. Interference fits also affect the maximum Hertz stress-life relation. Experimental data of Czyzewski, showing the effect of interference fit on rolling-element fatigue life, were reanalyzed to determine the shear stress-life exponent. The Czyzewski data shear stress-life exponent c equals 8.77, compared with the assumed value of 9. Results are presented as tables and charts of life factors for angular-contact and deep-groove ball bearings with light, normal, and heavy loads and interference fits ranging from extremely light to extremely heavy.

  4. Socioeconomic Factors Affecting Local Support for Black Bear Recovery Strategies

    Science.gov (United States)

    Morzillo, Anita T.; Mertig, Angela G.; Hollister, Jeffrey W.; Garner, Nathan; Liu, Jianguo

    2010-06-01

    There is global interest in recovering locally extirpated carnivore species. Successful efforts to recover Louisiana black bear in Louisiana have prompted interest in recovery throughout the species’ historical range. We evaluated support for three potential black bear recovery strategies prior to public release of a black bear conservation and management plan for eastern Texas, United States. Data were collected from 1,006 residents living in proximity to potential recovery locations, particularly Big Thicket National Preserve. In addition to traditional logistic regression analysis, we used conditional probability analysis to statistically and visually evaluate probabilities of public support for potential black bear recovery strategies based on socioeconomic characteristics. Allowing black bears to repopulate the region on their own (i.e., without active reintroduction) was the recovery strategy with the greatest probability of acceptance. Recovery strategy acceptance was influenced by many socioeconomic factors. Older and long-time local residents were most likely to want to exclude black bears from the area. Concern about the problems that black bears may cause was the only variable significantly related to support or non-support across all strategies. Lack of personal knowledge about black bears was the most frequent reason for uncertainty about preferred strategy. In order to reduce local uncertainty about possible recovery strategies, we suggest that wildlife managers focus outreach efforts on providing local residents with general information about black bears, as well as information pertinent to minimizing the potential for human-black bear conflict.

  5. Structure Design and Performance Analysis of High-Speed Miniature Ball Bearing

    Science.gov (United States)

    Li, Songsheng; Zhang, Guoye; Chen, Bin; Shen, Yuan

    2017-07-01

    The working performances of miniature ball bearings are obviously affected by its’ geometric structure parameters. In this paper, quasi-static analysis theory is applied in the design of miniature ball bearings. Firstly, it is studied the influence of geometry structure, preload and rotating speed on the dynamic performance of bearing. Secondly, bearing dynamic characteristics are analyzed which include the bearing stiffness and Spin to roll Ratio. Lastly, the contact stress and bearing life are calculated. The results indicate that structure parameters play an importance role in bearing’s dynamic performances. Miniature ball bearings which have lager ball number, bigger ball diameter and smaller inner race groove radius can get better performances while velocity and preload have great impact on the bearing life. So that parameters of miniature bearing should be chosen cautiously.

  6. Thermal conductivity of hydrate-bearing sediments

    Science.gov (United States)

    Cortes, Douglas D.; Martin, Ana I.; Yun, Tae Sup; Francisca, Franco M.; Santamarina, J. Carlos; Ruppel, Carolyn D.

    2009-01-01

    A thorough understanding of the thermal conductivity of hydrate-bearing sediments is necessary for evaluating phase transformation processes that would accompany energy production from gas hydrate deposits and for estimating regional heat flow based on the observed depth to the base of the gas hydrate stability zone. The coexistence of multiple phases (gas hydrate, liquid and gas pore fill, and solid sediment grains) and their complex spatial arrangement hinder the a priori prediction of the thermal conductivity of hydrate-bearing sediments. Previous studies have been unable to capture the full parameter space covered by variations in grain size, specific surface, degree of saturation, nature of pore filling material, and effective stress for hydrate-bearing samples. Here we report on systematic measurements of the thermal conductivity of air dry, water- and tetrohydrofuran (THF)-saturated, and THF hydrate–saturated sand and clay samples at vertical effective stress of 0.05 to 1 MPa (corresponding to depths as great as 100 m below seafloor). Results reveal that the bulk thermal conductivity of the samples in every case reflects a complex interplay among particle size, effective stress, porosity, and fluid-versus-hydrate filled pore spaces. The thermal conductivity of THF hydrate–bearing soils increases upon hydrate formation although the thermal conductivities of THF solution and THF hydrate are almost the same. Several mechanisms can contribute to this effect including cryogenic suction during hydrate crystal growth and the ensuing porosity reduction in the surrounding sediment, increased mean effective stress due to hydrate formation under zero lateral strain conditions, and decreased interface thermal impedance as grain-liquid interfaces are transformed into grain-hydrate interfaces.

  7. Effect of Silicon Nitride Balls and Rollers on Rolling Bearing Life

    Science.gov (United States)

    Zaretsky, Erwin V.; Vlcek, Brian L.; Hendricks, Robert C.

    2005-01-01

    Three decades have passed since the introduction of silicon nitride rollers and balls into conventional rolling-element bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel bearings. Life factors were determined and reported for hybrid bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and cylindrical roller hybrid bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid bearings are predicted to have a lower fatigue life than all-steel bearings by 58 percent for deep-groove bearings, 41 percent for angular-contact bearings, and 28 percent for cylindrical roller bearings.

  8. GIS representation of coal-bearing areas in Antarctica

    Science.gov (United States)

    Merrill, Matthew D.

    2016-03-11

    Understanding the distribution of coal-bearing geologic units in Antarctica provides information that can be used in sedimentary, geomorphological, paleontological, and climatological studies. This report is a digital compilation of information on Antarctica’s coal-bearing geologic units found in the literature. It is intended to be used in small-scale spatial geographic information system (GIS) investigations and as a visual aid in the discussion of Antarctica’s coal resources or in other coal-based geologic investigations. Instead of using spatially insignificant point markers to represent large coal-bearing areas, this dataset uses polygons to represent actual coal-bearing lithologic units. Specific locations of coal deposits confirmed from the literature are provided in the attribution for the coal-bearing unit polygons. Coal-sample-location data were used to confirm some reported coal-bearing geology. The age and extent of the coal deposits indicated in the literature were checked against geologic maps ranging from local scale at 1:50,000 to Antarctic continental scale at 1:5,000,000; if satisfactory, the map boundaries were used to generate the polygons for the coal-bearing localities.

  9. Gene transcription in polar bears (Ursus maritimus) from disparate populations

    Science.gov (United States)

    Bowen, Lizabeth; Miles, A. Keith; Waters, Shannon C.; Meyerson, Randi; Rode, Karyn D.; Atwood, Todd C.

    2015-01-01

    Polar bears in the Beaufort (SB) and Chukchi (CS) Seas experience different environments due primarily to a longer history of sea ice loss in the Beaufort Sea. Ecological differences have been identified as a possible reason for the generally poorer body condition and reproduction of Beaufort polar bears compared to those from the Chukchi, but the influence of exposure to other stressors remains unknown. We use molecular technology, quantitative PCR, to identify gene transcription differences among polar bears from the Beaufort and Chukchi Seas as well as captive healthy polar bears. We identified significant transcriptional differences among a priori groups (i.e., captive bears, SB 2012, SB 2013, CS 2013) for ten of the 14 genes of interest (i.e., CaM, HSP70, CCR3, TGFβ, COX2, THRα, T-bet, Gata3, CD69, and IL17); transcription levels of DRβ, IL1β, AHR, and Mx1 did not differ among groups. Multivariate analysis also demonstrated separation among the groups of polar bears. Specifically, we detected transcript profiles consistent with immune function impairment in polar bears from the Beaufort Sea, when compared with Chukchi and captive polar bears. Although there is no strong indication of differential exposure to contaminants or pathogens between CS and SB bears, there are clearly differences in important transcriptional responses between populations. Further investigation is warranted to refine interpretation of potential effects of described stress-related conditions for the SB population.

  10. Stress, burnout, and job satisfaction in 470 health professionals in 98 apheresis units in Italy: A SIdEM collaborative study.

    Science.gov (United States)

    Tremolada, Marta; Schiavo, Simone; Tison, Tiziana; Sormano, Emilia; De Silvestro, Giustina; Marson, Piero; Pierelli, Luca

    2015-10-01

    In Italian and international background, there are no studies focusing on stress, burnout indicators, and job satisfaction in health professionals working in the apheresis units. This study aims to fill this void both for scientific and clinical reasons. The participants were 470 health professionals (220 physicians, 250 nurses), mostly female (73.4%), with an average age of 48.09 (with the 5° percentile under 32 years and the 95° percentile over 60), working in the Apheresis Units in the North (228), in the Center (131) and in the Southern-islands of Italy (111). The health professionals' years on the job were principally between one and 10 years (40.2%) or from 11 to 20 years (33.2%). The prevalent activity was therapeutic apheresis (48.5%). The self-report questionnaires were proposed electronically by a protected online site. Important stress levels were identified in the health professionals. Physicians principally showed medium (47.5%) and high (35.8%) stress levels. Stress levels of nurses were mostly low (57.7%) or medium (25.7%). Female gender in nurses [t(268) = -3.29; P = 0.001] and in physician professions [t(217) = -3.01; P = 0.03] was a risk factor for stress. Both job categories were placed at a high risk level for burnout syndrome comparing with normative scales, especially the health professionals working in the center of Italy for the scales "Emotional exhaustion" [F(2) = 4.39; P = 0.013] and "Professional inefficacy" [F(2) = 4.38; P = 0.013]. Health professionals working in the apheresis unit show high stress levels and burnout risk. New preventive programs and specific clinical interventions should be constructed. © 2015 Wiley Periodicals, Inc.

  11. Magnetically leviated superconducting bearing

    Science.gov (United States)

    Weinberger, Bernard R.; Lynds, Jr., Lahmer

    1993-01-01

    A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

  12. The five-factor model of personality, work stress and professional quality of life in neonatal intensive care unit nurses.

    Science.gov (United States)

    Barr, Peter

    2018-06-01

    The study aim was to determine the direct and indirect relations of the five-factor model of personality traits and work stress with professional quality of life in neonatal nurses. Neonatal intensive care nursing has positive and negative effects on neonatal nurses' psychological well-being. Although individual and situational factors interact to influence professional quality of life, there have been few studies of these relationships in neonatal nurses. A cross-sectional study conducted in 2016. Self-report questionnaires were used to measure professional quality of life (burnout, secondary traumatic stress and compassion satisfaction), five-factor model of personality traits (neuroticism, agreeableness, extraversion, conscientiousness and openness) and work stress (role ambiguity, role conflict and role overload). One hundred and forty (34%) of 405 eligible neonatal nurses provided the data. After controlling for work stress, neuroticism and agreeableness were related to burnout, neuroticism was related to secondary traumatic stress, and extraversion was related to compassion satisfaction. Work stress controlled for personality traits was related to burnout and secondary traumatic stress, but not to compassion satisfaction. Neuroticism moderated the effect of work stress on secondary traumatic stress and agreeableness and openness moderated the effect of work stress on compassion satisfaction. Work stress mediated the effect of neuroticism and extraversion on burnout and the effects of extraversion and conscientiousness on compassion satisfaction. Strategies to reduce work stress may not lessen burnout and secondary traumatic stress or increase compassion satisfaction in neonatal nurses who are prone to high neuroticism, low agreeableness and low extraversion. © 2018 John Wiley & Sons Ltd.

  13. Dementia care worker stress associations with unit type, resident, and work environment characteristics: a cross-sectional secondary data analysis of the Swiss Nursing Homes Human Resources Project (SHURP).

    Science.gov (United States)

    Vogel, Barbara; De Geest, Sabina; Fierz, Katharina; Beckmann, Sonja; Zúñiga, Franziska

    2017-03-01

    Although caring for residents with dementia in nursing homes is associated with various stressors for care workers, the role of the unit type, and particularly the proportion of residents with dementia, remains unclear. This study aimed to explore associations between unit type and care worker stress, taking into account additional potential stressors. This cross-sectional study was a secondary data analysis in the Swiss Nursing Homes Human Resources Project, which included data from 3,922 care workers from 156 Swiss nursing homes. Care workers' stress was measured with a shortened version of the Health Professions Stress Inventory. Generalized estimating equation models were used to assess care worker stress and its relationships with three unit types (special care units and others with high or low proportions of residents with dementia), work environment factors, and aggressive resident behavior. After including all potential stressors in the models, no significant differences between the three unit types regarding care worker stress were found. However, increased care worker stress levels were significantly related to lower ratings of staffing and resources adequacy, the experience of verbal aggression, and the observation of verbal or physical aggression among residents. Although the unit type plays only a minor role regarding care worker stress, this study confirms that work environment and aggressive behavior of residents are important factors associated with work-related stress. To prevent increases of care worker stress, interventions to improve the work environment and strengthen care workers' ability to cope with aggressive behavior are suggested.

  14. Within-unit relationship quality mediates the association between military sexual trauma and posttraumatic stress symptoms in veterans separating from military service.

    Science.gov (United States)

    Laws, Holly; Mazure, Carolyn M; McKee, Sherry A; Park, Crystal L; Hoff, Rani

    2016-09-01

    Few studies have examined the impact of military sexual trauma (MST) on social functioning during deployment. Yet consideration of unit relationships during deployment may be important, given that military unit cohesion and support can provide protective effects against the stress of combat, and reduce the likelihood of developing posttraumatic stress disorder. Although prior research has posited that depleted social resources are one pathway through which MST is associated with posttraumatic stress symptoms (PTSS), no studies have statistically tested this theory. This study examined the association of MST and PTSS and evaluated the potential mediating role of decreased unit relationship quality. Mediational analyses were conducted on a sample of veterans following discharge from military service (N = 818; 328 women, 490 men). Women were significantly more likely to experience MST than men. As hypothesized, experiences of MST during deployment were associated with higher PTSS. MST experiences were associated with less trust in and support from one's military unit, which partially mediated the association between MST and PTSS. The indirect effect of MST on PTSS through lower unit relationship quality accounted for 20.4% of the total effect of MST on PTSS. While the retrospective study design precludes tests of causality, mediational findings provided statistical evidence that lower unit relationship quality partially explains the association between MST and PTSS. This finding is consistent with interpersonal theories of trauma response suggesting that the deleterious effects of MST may be in part due to its erosion of social resources during deployment. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  15. Neuromuscular Stress.

    Science.gov (United States)

    White, Timothy P.; Kern, Marialice

    1994-01-01

    Discusses exercise-induced stress that results from motor unit recruitment, the impact of recruitment on selected systemic support systems, and some of the environmental overlays that affect the degree of physiological stress. Adaptations to sustained changes in physical activity and muscle and myotendinous injury induced by stress are examined.…

  16. Defining in-situ stress magnitude and the responses of geology to stress anisotropy in heterogeneous lithologies for the United Kingdom

    Science.gov (United States)

    Kingdon, A.; Fellgett, M. W.; Williams, J. D. O.

    2017-12-01

    Exploitation of shale gas in the USA has led to interest in similar UK deposits. After tremors at the Preese Hall well in 2011, the process of hydraulic fracturing has become contentious. In-situ stress orientation controls the direction that fractures propagate from a well. World Stress Map (WSM) data coverage for the UK has historically been sparse. Improvements to the stress orientations for the UK are vital for reducing risk levels of induced seismicity. In some offshore basins, maximum horizontal stress (SHMax) is sub-parallel to major inverted Permo-Triassic faults, episodically reactivated during the Cenozoic, indicating a degree of structural control. Understanding for UK stress magnitude has been poor. Data for Northern England has been augmented with new estimates of vertical stress (Sv), minimum horizontal stress (Shmin) and pore pressure, focussed on potentially prospective basins east and west of the Pennines. Calculated values combined with legacy hydraulic fracturing and overcoring data show vertical stress gradients vary from 23 to 26 MPa/Km-1. Cheshire and Scotland show higher Shmin values by 2 MPa/Km-1 compared to Yorkshire and South East England. SHMax values exceeds the Sv which in turn exceeds Shmin indicating a predominantly strike slip environment. Pore pressure appears to be uniformly hydrostatic across the studied regions. There is some evidence above 1200 m depth of reverse faulting in igneous rocks in Cornwall, Leicestershire and Cumbria. Analysis of borehole imaging for the lithologically heterogeneous Carboniferous Coal Measures, highlights variability failure modes over confined vertical intervals. Breakouts are disproportionately located in "seatearths", palaeosols located stratigraphically beneath coal seams. Drilling induced tensile fractures are located within close proximity in overbank silt/clay facies and relatively massive channel sands that typically over and underlie coal deposits. Strength tests show that breakouts occur in

  17. Actuators for Active Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    Eric H. Maslen

    2017-10-01

    Full Text Available The literature of active magnetic bearing (AMB technology dates back to at least 1937 when the earliest work that clearly describes an active magnetic bearing system was published by Jesse Beams [...

  18. Development of stress ulcers assessed by gastric electrical potential difference, pH of gastric juice, and endoscopy in patients in the intensive care unit

    DEFF Research Database (Denmark)

    Rubinstein, E; Gjørup, I; Schulze, S

    1992-01-01

    OBJECTIVE: To assess measurement of gastric electrical potential difference, pH of gastric mucosa, and endoscopic findings in patients in intensive care units who are at risk of developing stress ulcers. DESIGN: Open comparison with age- and sex-matched control subjects. SETTING: Herlev Hospital......, Denmark. SUBJECTS: Sixteen consecutive patients with no history of gastrointestinal haemorrhage, coagulopathy, or ulcer disease who had been admitted to the intensive care unit, and 16 age- and sex-matched outpatients with normal endoscopic findings. INTERVENTIONS: Upper gastrointestinal endoscopy, during...... which any lesions that were found were scored according to severity, the gastric potential difference, and the pH of gastric juice were measured. OUTCOME MEASURES: Correlation between the incidence of stress ulceration found at endoscopy, gastric potential difference, and gastric pH. RESULTS: Gastric...

  19. Grizzly bear density in Glacier National Park, Montana

    Science.gov (United States)

    Kendall, K.C.; Stetz, J.B.; Roon, David A.; Waits, L.P.; Boulanger, J.B.; Paetkau, David

    2008-01-01

    We present the first rigorous estimate of grizzly bear (Ursus arctos) population density and distribution in and around Glacier National Park (GNP), Montana, USA. We used genetic analysis to identify individual bears from hair samples collected via 2 concurrent sampling methods: 1) systematically distributed, baited, barbed-wire hair traps and 2) unbaited bear rub trees found along trails. We used Huggins closed mixture models in Program MARK to estimate total population size and developed a method to account for heterogeneity caused by unequal access to rub trees. We corrected our estimate for lack of geographic closure using a new method that utilizes information from radiocollared bears and the distribution of bears captured with DNA sampling. Adjusted for closure, the average number of grizzly bears in our study area was 240.7 (95% CI = 202–303) in 1998 and 240.6 (95% CI = 205–304) in 2000. Average grizzly bear density was 30 bears/1,000 km2, with 2.4 times more bears detected per hair trap inside than outside GNP. We provide baseline information important for managing one of the few remaining populations of grizzlies in the contiguous United States.

  20. Cost Analysis Of Replacement And Bearing Trailer Maintenance In Sugar Group Companies

    OpenAIRE

    Mastur, Mastur; Masyhuri, Masyhuri; Waluyati, Lestari Rahayu

    2017-01-01

    The purpose of this study are to understand (i) the costs and periods optimal of grease used for the replacement and maintenance bearing trailer in Sugar Group Companies (SGC), and (ii) the effect of a period and frequency of grease, lifetime bearing, frequency of replacement bearing in a year, unit trailer, brand bearing, and location of plant. The basic method used is descriptive and analytical. The location determined were in Workshop Division PT. ILP, PT. SIL, and PT. GPM. The analytical ...

  1. Physically elastic analysis of a cylindrical ring as a unit cell of a complete composite under applied stress in the complex plane using cubic polynomials

    Science.gov (United States)

    Monfared, Vahid

    2018-03-01

    Elastic analysis is analytically presented to predict the behaviors of the stress and displacement components in the cylindrical ring as a unit cell of a complete composite under applied stress in the complex plane using cubic polynomials. This analysis is based on the complex computation of the stress functions in the complex plane and polar coordinates. Also, suitable boundary conditions are considered and assumed to analyze along with the equilibrium equations and bi-harmonic equation. This method has some important applications in many fields of engineering such as mechanical, civil and material engineering generally. One of the applications of this research work is in composite design and designing the cylindrical devices under various loadings. Finally, it is founded that the convergence and accuracy of the results are suitable and acceptable through comparing the results.

  2. Delayed child-bearing.

    Science.gov (United States)

    Johnson, Jo-Ann; Tough, Suzanne

    2012-01-01

    To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely

  3. Government Risk-Bearing

    CERN Document Server

    1993-01-01

    The u.s. government bulks large in the nation's financial markets. The huge volume of government-issued and -sponsored debt affects the pricing and volume ofprivate debt and, consequently, resource allocation between competing alternatives. What is often not fully appreciated is the substantial influence the federal government wields overresource allocation through its provisionofcreditandrisk-bearing services to the private economy. Because peopleand firms generally seekto avoid risk, atsomeprice they are willing to pay another party to assume the risk they would otherwise face. Insurance companies are a class of private-sector firms one commonly thinks of as providing these services. As the federal government has expanded its presence in the U.S. economy during this century, it has increasingly developed programs aimed at bearing risks that the private sector either would not take on at any price, or would take on but atapricethoughtto besogreatthatmostpotentialbeneficiarieswouldnotpurchase the coverage. To...

  4. Passive magnetic bearing system

    Science.gov (United States)

    Post, Richard F.

    2014-09-02

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  5. Spatial Distribution of Black Bear Incident Reports in Michigan.

    Science.gov (United States)

    McFadden-Hiller, Jamie E; Beyer, Dean E; Belant, Jerrold L

    2016-01-01

    Interactions between humans and carnivores have existed for centuries due to competition for food and space. American black bears are increasing in abundance and populations are expanding geographically in many portions of its range, including areas that are also increasing in human density, often resulting in associated increases in human-bear conflict (hereafter, bear incidents). We used public reports of bear incidents in Michigan, USA, from 2003-2011 to assess the relative contributions of ecological and anthropogenic variables in explaining the spatial distribution of bear incidents and estimated the potential risk of bear incidents. We used weighted Normalized Difference Vegetation Index mean as an index of primary productivity, region (i.e., Upper Peninsula or Lower Peninsula), primary and secondary road densities, and percentage land cover type within 6.5-km2 circular buffers around bear incidents and random points. We developed 22 a priori models and used generalized linear models and Akaike's Information Criterion (AIC) to rank models. The global model was the best compromise between model complexity and model fit (w = 0.99), with a ΔAIC 8.99 units from the second best performing model. We found that as deciduous forest cover increased, the probability of bear incident occurrence increased. Among the measured anthropogenic variables, cultivated crops and primary roads were the most important in our AIC-best model and were both positively related to the probability of bear incident occurrence. The spatial distribution of relative bear incident risk varied markedly throughout Michigan. Forest cover fragmented with agriculture and other anthropogenic activities presents an environment that likely facilitates bear incidents. Our map can help wildlife managers identify areas of bear incident occurrence, which in turn can be used to help develop strategies aimed at reducing incidents. Researchers and wildlife managers can use similar mapping techniques to

  6. Spatial Distribution of Black Bear Incident Reports in Michigan.

    Directory of Open Access Journals (Sweden)

    Jamie E McFadden-Hiller

    Full Text Available Interactions between humans and carnivores have existed for centuries due to competition for food and space. American black bears are increasing in abundance and populations are expanding geographically in many portions of its range, including areas that are also increasing in human density, often resulting in associated increases in human-bear conflict (hereafter, bear incidents. We used public reports of bear incidents in Michigan, USA, from 2003-2011 to assess the relative contributions of ecological and anthropogenic variables in explaining the spatial distribution of bear incidents and estimated the potential risk of bear incidents. We used weighted Normalized Difference Vegetation Index mean as an index of primary productivity, region (i.e., Upper Peninsula or Lower Peninsula, primary and secondary road densities, and percentage land cover type within 6.5-km2 circular buffers around bear incidents and random points. We developed 22 a priori models and used generalized linear models and Akaike's Information Criterion (AIC to rank models. The global model was the best compromise between model complexity and model fit (w = 0.99, with a ΔAIC 8.99 units from the second best performing model. We found that as deciduous forest cover increased, the probability of bear incident occurrence increased. Among the measured anthropogenic variables, cultivated crops and primary roads were the most important in our AIC-best model and were both positively related to the probability of bear incident occurrence. The spatial distribution of relative bear incident risk varied markedly throughout Michigan. Forest cover fragmented with agriculture and other anthropogenic activities presents an environment that likely facilitates bear incidents. Our map can help wildlife managers identify areas of bear incident occurrence, which in turn can be used to help develop strategies aimed at reducing incidents. Researchers and wildlife managers can use similar mapping

  7. Stacked magnet superconducting bearing

    International Nuclear Information System (INIS)

    Rigney, T.K. II; Saville, M.P.

    1993-01-01

    A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines

  8. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  9. Magnetic translator bearings

    Science.gov (United States)

    Hockney, Richard L. (Inventor); Downer, James R. (Inventor); Eisenhaure, David B. (Inventor); Hawkey, Timothy J. (Inventor); Johnson, Bruce G. (Inventor)

    1990-01-01

    A magnetic bearing system for enabling translational motion includes a carriage and a shaft for movably supporting the carriage; a first magnetic bearing fixed to one of the carriage and shaft and slidably received in a first channel of the other of the carriage and shaft. The first channel is generally U shaped with two side walls and a back wall. The magnetic bearing includes a pair of spaced magnetic pole pieces, each pole piece having a pair of electromagnetic coils mounted on poles on opposite ends of the pole piece proximate the side walls, and a third electromagnetic coil mounted on a pole of the pole piece proximate the backwall; a motion sensor for sensing translational motion along two axes and rotationally about three axes of the carriage and shaft relative to each other; and a correction circuit responsive to the sensor for generating a correction signal to drive the coils to compensate for any misalignment sensed between the carriage and the shaft.

  10. Job Stress and Locus of Control in Teachers: Comparisons between Samples from the United States and Zimbabwe

    Science.gov (United States)

    Crothers, Laura M.; Kanyongo, Gibbs Y.; Kolbert, Jered B.; Lipinski, John; Kachmar, Steven P.; Koch, Gary D.

    2010-01-01

    This study examines the relationship between educators' locus of control and job stress using samples from the US and Zimbabwe. Multiple regression analyses are used to identify significant relationships in the US sample between teachers' external locus of control and the severity of the job stress that they experience, coupled with the perceived…

  11. Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing

    Science.gov (United States)

    Ream, L. W.

    1974-01-01

    A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.

  12. Clinical validity of a relocation stress scale for the families of patients transferred from intensive care units.

    Science.gov (United States)

    Oh, HyunSoo; Lee, Seul; Kim, JiSun; Lee, EunJu; Min, HyoNam; Cho, OkJa; Seo, WhaSook

    2015-07-01

    This study was conducted to develop a family relocation stress scale by modifying the Son's Relocation Stress Syndrome Scale, to examine its clinical validity and reliability and to confirm its suitability for measuring family relocation stress. The transfer of ICU patients to general wards is a significant anxiety-producing event for family members. However, no relocation stress scale has been developed specifically for families. A nonexperimental, correlation design was adopted. The study subjects were 95 family members of 95 ICU patients at a university hospital located in Incheon, South Korea. Face and construct validities of the devised family relocation stress scale were examined. Construct validity was examined using factor analysis and by using a nomological validity test. Reliability was also examined. Face and content validity of the scale were verified by confirming that its items adequately measured family relocation stress. Factor analysis yielded four components, and the total variance explained by these four components was 63·0%, which is acceptable. Nomological validity was well supported by significant relationships between relocation stress and degree of preparation for relocation, patient self-care ability, family burden and satisfaction with the relocation process. The devised scale was also found to have good reliability. The family relocation stress scale devised in this study was found to have good validity and reliability, and thus, is believed to offer a means of assessing family relocation stress. The findings of this study provide a reliable and valid assessment tool when nurses prepare families for patient transfer from an ICU to a ward setting, and may also provide useful information to those developing an intervention programme for family relocation stress management. © 2015 John Wiley & Sons Ltd.

  13. Food and mental health: relationship between food and perceived stress and depressive symptoms among university students in the United Kingdom.

    Science.gov (United States)

    El Ansari, Walid; Adetunji, Hamed; Oskrochi, Reza

    2014-06-01

    The current study assessed, by university and sex, the association between nutritional behaviour (twelve independent variables), and stress and depressive symptoms (dependent variables) in a sample from three UK countries. A cross-sectional survey was undertaken among undergraduates enrolled across seven universities in England, Wales and Northern Ireland (N = 3,706). Self-administered questionnaires included a 12-item food frequency questionnaire, Cohen's Perceived Stress Scale and modified Beck Depression Inventory. Sex and university comparisons were undertaken. Univariable and multivariable regression analyses were computed for each of the two outcomes--perceived stress and depressive symptoms. The frequencies of consuming of the various food groups differed by university and sex, as did depressive symptoms and perceived stress. Multivariable regression analyses indicated that consuming 'unhealthy' foods (e.g. sweets, cookies, snacks, fast food) was significantly positively associated with perceived stress (females only) and depressive symptoms (both males and females). Conversely, consuming 'healthy' foods (e.g. fresh fruits, salads, cooked vegetables) was significantly negatively associated with perceived stress and depressive symptoms scores for both sexes. There was significant negative association between consuming fish/sea food and depressive symptoms among males only. For males and for females, consuming lemonade/soft drinks, meat/sausage products, dairy/dairy products, and cereal/cereal products were not associated with either perceived stress or depressive symptoms. The associations between consuming 'unhealthy' foods and higher depressive symptoms and perceived stress among male and female students as well as the associations between consuming 'healthy' foods and lower depressive symptoms and perceived stress among male and female students in three UK countries suggest that interventions to reduce depressive symptoms and stress among students could

  14. Bearing for liquid metal pump

    International Nuclear Information System (INIS)

    Dickinson, R.J.; Pennell, W.E.; Wasko, J.

    1984-01-01

    A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

  15. Water stress from high-volume hydraulic fracturing potentially threatens aquatic biodiversity and ecosystem services in Arkansas, United States

    Science.gov (United States)

    Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly O.; Fargione, Joseph; Kiesecker, Joseph M.; Baruch-Mordo, Sharon; Konschnik, Katherine E.; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N.

    2018-01-01

    Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and “frack” ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7–51% of catchments from June–November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

  16. Water Stress from High-Volume Hydraulic Fracturing Potentially Threatens Aquatic Biodiversity and Ecosystem Services in Arkansas, United States.

    Science.gov (United States)

    Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly; Fargione, Joseph; Kiesecker, Joseph; Baruch-Mordo, Sharon; Konschnik, Katherine; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N

    2018-02-20

    Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and "frack" ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7-51% of catchments from June-November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

  17. The Energetic Value of Land-Based Foods in Western Hudson Bay and Their Potential to Alleviate Energy Deficits of Starving Adult Male Polar Bears.

    Directory of Open Access Journals (Sweden)

    Linda J Gormezano

    Full Text Available Climate change is predicted to expand the ice-free season in western Hudson Bay and when it grows to 180 days, 28-48% of adult male polar bears are projected to starve unless nutritional deficits can be offset by foods consumed on land. We updated a dynamic energy budget model developed by Molnar et al. to allow influx of additional energy from novel terrestrial foods (lesser snow geese, eggs, caribou that polar bears currently consume as part of a mixed diet while on land. We calculated the units of each prey, alone and in combination, needed to alleviate these lethal energy deficits under conditions of resting or limited movement (2 km d-1 prior to starvation. We further considered the total energy available from each sex and age class of each animal prey over the period they would overlap land-bound polar bears and calculated the maximum number of starving adult males that could be sustained on each food during the ice-free season. Our results suggest that the net energy from land-based food, after subtracting costs of limited movement to obtain it, could eliminate all projected nutritional deficits of starving adult male polar bears and likely other demographic groups as well. The hunting tactics employed, success rates as well as behavior and abundance of each prey will determine the realized energetic values for individual polar bears. Although climate change may cause a phenological mismatch between polar bears and their historical ice-based prey, it may simultaneously yield a new match with certain land-based foods. If polar bears can transition their foraging behavior to effectively exploit these resources, predictions for starvation-related mortality may be overestimated for western Hudson Bay. We also discuss potential complications with stable-carbon isotope studies to evaluate utilization of land-based foods by polar bears including metabolic effects of capture-related stress and consuming a mixed diet.

  18. The Energetic Value of Land-Based Foods in Western Hudson Bay and Their Potential to Alleviate Energy Deficits of Starving Adult Male Polar Bears.

    Science.gov (United States)

    Gormezano, Linda J; Rockwell, Robert F

    2015-01-01

    Climate change is predicted to expand the ice-free season in western Hudson Bay and when it grows to 180 days, 28-48% of adult male polar bears are projected to starve unless nutritional deficits can be offset by foods consumed on land. We updated a dynamic energy budget model developed by Molnar et al. to allow influx of additional energy from novel terrestrial foods (lesser snow geese, eggs, caribou) that polar bears currently consume as part of a mixed diet while on land. We calculated the units of each prey, alone and in combination, needed to alleviate these lethal energy deficits under conditions of resting or limited movement (2 km d-1) prior to starvation. We further considered the total energy available from each sex and age class of each animal prey over the period they would overlap land-bound polar bears and calculated the maximum number of starving adult males that could be sustained on each food during the ice-free season. Our results suggest that the net energy from land-based food, after subtracting costs of limited movement to obtain it, could eliminate all projected nutritional deficits of starving adult male polar bears and likely other demographic groups as well. The hunting tactics employed, success rates as well as behavior and abundance of each prey will determine the realized energetic values for individual polar bears. Although climate change may cause a phenological mismatch between polar bears and their historical ice-based prey, it may simultaneously yield a new match with certain land-based foods. If polar bears can transition their foraging behavior to effectively exploit these resources, predictions for starvation-related mortality may be overestimated for western Hudson Bay. We also discuss potential complications with stable-carbon isotope studies to evaluate utilization of land-based foods by polar bears including metabolic effects of capture-related stress and consuming a mixed diet.

  19. Bearing construction for refrigeration compresssor

    Science.gov (United States)

    Middleton, Marc G.; Nelson, Richard T.

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  20. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

  1. Ab initio study of symmetrical tilt grain boundaries in bcc Fe: structural units, magnetic moments, interfacial bonding, local energy and local stress

    International Nuclear Information System (INIS)

    Bhattacharya, Somesh Kr; Tanaka, Shingo; Kohyama, Masanori; Shiihara, Yoshinori

    2013-01-01

    We present first-principle calculations on symmetric tilt grain boundaries (GBs) in bcc Fe. Using density functional theory (DFT), we studied the structural, electronic and magnetic properties of Σ3(111) and Σ11(332) GBs formed by rotation around the [110] axis. The optimized structures, GB energies and GB excess free volumes are consistent with previous DFT and classical simulation studies. The GB configurations can be interpreted by the structural unit model as given by Nakashima and Takeuchi (2000 ISIJ 86 357). Both the GBs are composed of similar structural units of three- and five-membered rings with different densities at the interface according to the rotation angle. The interface atoms with larger atomic volumes reveal higher magnetic moments than the bulk value, while the interface atoms with shorter bond lengths have reduced magnetic moments in each GB. The charge density and local density of states reveal that the interface bonds with short bond lengths have more covalent nature, where minority-spin electrons play a dominant role as the typical nature of ferromagnetic Fe. In order to understand the structural stability of these GBs, we calculated the local energy and local stress for each atomic region using the scheme of Shiihara et al (2010 Phys. Rev. B 81 075441). In each GB, the interface atoms with larger atomic volumes and enhanced magnetic moments reveal larger local energy increase and tensile stress. The interface atoms constituting more covalent-like bonds with reduced magnetic moments have lower local energy increase, contributing to the stabilization, while compressive stress is generated at these atoms. The relative stability between the two GBs can be understood by the local energies at the structural units. The local energy and local stress analysis is a powerful tool to investigate the structural properties of GBs based on the behavior of valence electrons. (paper)

  2. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

  3. The Effects of Emotional Intelligence (EI Items Education on Job Related Stress in Physicians and Nurses who Work in Intensive Care Units

    Directory of Open Access Journals (Sweden)

    Kh Nooryan

    2011-12-01

    Full Text Available Background & Aim: Intensive care units (ICUs are recognized as stressful environments. The objective of this study was to determine the effects of emotional intelligence education items on job related stress on physicians and nurses who work in intensive care units at hospitals of Yerevan, Armenia. Methods: A interventional study design was implemented with 106 registered hospital physicians and nurses, who were widely distributed all the way through. Case group was taught about 15 E.I items. For data collection, the 20-question Berger situational (overt anxiety questionnaire, the 20-item personality (covert anxiety questionnaire, and the Bar-on emotional intelligence questionnaire with 133 questions were used. Statistical descriptive methods, chi-square (X2 and t-tests were used to analyze data. Results: The research achievements revealed that the average score of the case group`s situational anxiety was 46.59 before intervention, which decreased to 39.95 after the training of the items of emotional intelligence. The average score of situational anxiety of control group was 44.32 before intervention which increased to 44.76 after examination. There was a meaningful statistical difference between case and control group after education of emotional intelligence`s items (p=0.001. Conclusion: Results of the current study showed that physicians and nurses experience high level of stress. The ability to effectively deal with emotion intelligence and emotional information in the workplace assists employees in coping with occupational stress and should be developed in stress managing trainings.

  4. Operational Stress Control and Readiness (OSCAR): The United States Marine Corps Initiative to Deliver Mental Health Services to Operating Forces

    National Research Council Canada - National Science Library

    Nash, William P

    2006-01-01

    .... The role of military mental health professionals in combat/operational stress control is to adapt scientific tools for prevention, identification, and treatment for use by military leaders at all levels...

  5. Prenatal Maternal Stress and Physical Abuse among Homeless Women and Infant Health Outcomes in the United States

    OpenAIRE

    Merrill, Ray M.; Richards, Rickelle; Sloan, Arielle

    2011-01-01

    Background. This study examines whether the relationship between maternal stress or abuse situations and infant birth weight differs between homeless and non-homeless women. Methods. Analyses are based on data from the Pregnancy Risk Assessment Monitoring System (PRAMS), 2002–2007. Results. Homeless women were significantly more likely to experience stressful life events, abusive situations, and poor maternal health than non-homeless women during pregnancy. Birth weight among infant...

  6. The economics of roadside bear viewing

    Science.gov (United States)

    Richardson, Leslie; Rosen, Tatjana; Gunther, Kerry; Schwartz, Chuck

    2014-01-01

    Viewing bears along roadside habitats is a popular recreational activity in certain national parks throughout the United States. However, safely managing visitors during traffic jams that result from this activity often requires the use of limited park resources. Using unique visitor survey data, this study quantifies economic values associated with roadside bear viewing in Yellowstone National Park, monetary values that could be used to determine whether this continued use of park resources is warranted on economic grounds. Based on visitor expenditure data and results of a contingent visitation question, it is estimated that summer Park visitation would decrease if bears were no longer allowed to stay along roadside habitats, resulting in a loss of 155 jobs in the local economy. Results from a nonmarket valuation survey question indicate that on average, visitors to Yellowstone National Park are willing to pay around $41 more in Park entrance fees to ensure that bears are allowed to remain along roads within the Park. Generalizing this value to the relevant population of visitors indicates that the economic benefits of allowing this wildlife viewing opportunity to continue could outweigh the costs of using additional resources to effectively manage these traffic jams.

  7. Self lubricating fluid bearings

    International Nuclear Information System (INIS)

    Kapich, D.D.

    1980-01-01

    The invention concerns self lubricating fluid bearings, which are used in a shaft sealed system extending two regions. These regions contain fluids, which have to be isolated. A first seal is fluid tight for the first region between the carter shaft and the shaft. The second seal is fluid tight between the carter and the shaft, it communicates with the second region. The first fluid region is the environment surrounding the shaft carter. The second fluid region is a part of a nuclear reactor which contains the cooling fluid. The shaft is conceived to drive a reactor circulating and cooling fluid [fr

  8. Exploitation of pocket gophers and their food caches by grizzly bears

    Science.gov (United States)

    Mattson, D.J.

    2004-01-01

    I investigated the exploitation of pocket gophers (Thomomys talpoides) by grizzly bears (Ursus arctos horribilis) in the Yellowstone region of the United States with the use of data collected during a study of radiomarked bears in 1977-1992. My analysis focused on the importance of pocket gophers as a source of energy and nutrients, effects of weather and site features, and importance of pocket gophers to grizzly bears in the western contiguous United States prior to historical extirpations. Pocket gophers and their food caches were infrequent in grizzly bear feces, although foraging for pocket gophers accounted for about 20-25% of all grizzly bear feeding activity during April and May. Compared with roots individually excavated by bears, pocket gopher food caches were less digestible but more easily dug out. Exploitation of gopher food caches by grizzly bears was highly sensitive to site and weather conditions and peaked during and shortly after snowmelt. This peak coincided with maximum success by bears in finding pocket gopher food caches. Exploitation was most frequent and extensive on gently sloping nonforested sites with abundant spring beauty (Claytonia lanceolata) and yampah (Perdieridia gairdneri). Pocket gophers are rare in forests, and spring beauty and yampah roots are known to be important foods of both grizzly bears and burrowing rodents. Although grizzly bears commonly exploit pocket gophers only in the Yellowstone region, this behavior was probably widespread in mountainous areas of the western contiguous United States prior to extirpations of grizzly bears within the last 150 years.

  9. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    2015-01-01

    Full Text Available With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP. Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

  10. Stress concentrations at structural discontinuities in active fault zones in the western United States: Implications for permeability and fluid flow in geothermal fields

    Science.gov (United States)

    Siler, Drew; Hinz, Nicholas H.; Faulds, James E.

    2018-01-01

    Slip can induce concentration of stresses at discontinuities along fault systems. These structural discontinuities, i.e., fault terminations, fault step-overs, intersections, bends, and other fault interaction areas, are known to host fluid flow in ore deposition systems, oil and gas reservoirs, and geothermal systems. We modeled stress transfer associated with slip on faults with Holocene-to-historic slip histories at the Salt Wells and Bradys geothermal systems in western Nevada, United States. Results show discrete locations of stress perturbation within discontinuities along these fault systems. Well field data, surface geothermal manifestations, and subsurface temperature data, each a proxy for modern fluid circulation in the fields, indicate that geothermal fluid flow is focused in these same areas where stresses are most highly perturbed. These results suggest that submeter- to meter-scale slip on these fault systems generates stress perturbations that are sufficiently large to promote slip on an array of secondary structures spanning the footprint of the modern geothermal activity. Slip on these secondary faults and fractures generates permeability through kinematic deformation and allows for transmission of fluids. Still, mineralization is expected to seal permeability along faults and fractures over time scales that are generally shorter than either earthquake recurrence intervals or the estimated life span of geothermal fields. This suggests that though stress perturbations resulting from fault slip are broadly important for defining the location and spatial extent of enhanced permeability at structural discontinuities, continual generation and maintenance of flow conduits throughout these areas are probably dependent on the deformation mechanism(s) affecting individual structures.

  11. A Brief Cognitive-Behavioral Psycho-Education (B-CBE Program for Managing Stress and Anxiety of Main Family Caregivers of Patients in the Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Vico Chung Lim Chiang

    2016-09-01

    Full Text Available Having a loved one in the intensive care unit (ICU is a stressful event, which may cause a high level of anxiety to the family members. This could threaten their wellbeing and ability to support the patients in, or after discharge from, the ICU. To investigate the outcomes of a brief cognitive-behavioral psycho-education program (B-CBE to manage stress and anxiety of the main family caregivers (MFCs, a pragmatic quasi-experimental study involving 45 participants (treatment group: 24; control group: 21 was conducted in an ICU. The Depression and Anxiety Stress Scale and the Critical Care Family Need Inventory were used to evaluate the primary outcomes on stress and anxiety, and satisfaction with family needs. The treatment group reported significantly better improvement in the information satisfaction score compared to the control group (p < 0.05; η2 = 0.09. Overall main effects were observed on the stress (p < 0.01; η2 = 0.20, anxiety (p < 0.01; η2 = 0.18, depression (p < 0.05; η2 = 0.13, support satisfaction (p < 0.05; η2 = 0.13, and comfort satisfaction (p < 0.05; η2 = 0.11 scores. The experience of this study suggest that MFCs are in great need of additional support like B-CBE to manage their stress and anxiety. Given the brevity of B-CBE, it is practical for critical care nurses to deliver and MFCs to take within the industrious context of an ICU. More studies are needed to investigate these types of brief psychological interventions.

  12. Nanoprecipitation in bearing steels

    International Nuclear Information System (INIS)

    Barrow, A.T.W.; Rivera-Diaz-del-Castillo, P.E.J.

    2011-01-01

    θ-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The θ-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

  13. Superconducting bearings in flywheels

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, T.A.; Campbell, A.M.; Ganney, I.; Lo, W. [Cambridge Univ. (United Kingdom). Interdisciplinary Research Centre in Superconductivity (IRC); Twardowski, T. [International Energy Systems, Chester High Road, Neston, South Wirral (United Kingdom); Dawson, B. [British Nuclear Fuels, Capenhurst, South Wirral (United Kingdom)

    1998-05-01

    Investigations are being carried out into the use of superconducting magnetic bearings to levitate energy storage flywheels. In a planned program of work, Cambridge University are aiming to produce a practical bearing system for Pirouette(TM). The Pirouette(TM) system is designed to provide 5 kWh of recoverable energy which is currently recoverable at a rate of 5 kW (future revisions will provide up to 50 kW). IES (a British Nuclear Fuels subsidiary) the owners of the Pirouette(TM) machine have supplied Cambridge with a flywheel. This flywheel weighs >40 kg and is being levitated using an Evershed-type arrangement in which the superconductor is being used to stabilize the interaction between two magnets. To date we have demonstrated stable levitation in static and low speed tests in a rig designed for low speeds of rotation in air. A second rig which is currently under construction at BNFL will run in vacuum at speeds of up to 50 (orig.) 5 refs.

  14. Psychological stress declines rapidly from age 50 in the United States: Yet another well-being paradox.

    Science.gov (United States)

    Stone, Arthur A; Schneider, Stefan; Broderick, Joan E

    2017-12-01

    Although there is evidence that evaluative subjective well-being (e.g., life satisfaction) shows a U-shaped pattern with highest satisfaction in the youngest and oldest years and lowest in the middle years of adulthood, much less is known about experiential well-being. We explore a negative indicator of experiential well-being (perceived stress), examine its association with age, and explore possible determinants of the age pattern. Using Gallup-Healthways survey data of over 1.5 million U.S. respondents, we analyzed a question asking about stress yesterday and demographic determinants of the pattern. To confirm this pattern, data on stress was analyzed from the American Time Use Survey and data on distress was analyzed from the Health and Retirement Survey. We show that ratings of daily, perceived stressfulness yield a paradox, with high levels from the 20's through about age 50, followed by a precipitous decline through the 70's. Data from the other two surveys confirmed the age pattern for stress. Regressions with the Gallup-Healthways data statistically controlled several third-variables, yet none substantially altered the pattern. We argue that this new experiential well-being pattern informs us about aging in the US and the "paradox" calls out for explanation. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Resources predicting positive and negative affect during the experience of stress: a study of older Asian Indian immigrants in the United States.

    Science.gov (United States)

    Diwan, Sadhna; Jonnalagadda, Satya S; Balaswamy, Shantha

    2004-10-01

    Using the life stress model of psychological well-being, in this study we examined risks and resources predicting the occurrence of both positive and negative affect among older Asian Indian immigrants who experienced stressful life events. We collected data through a telephone survey of 226 respondents (aged 50 years and older) in the Southeastern United States. We used hierarchical, negative binomial regression analyses to examine correlates of positive and negative affect. Different coping resources influenced positive and negative affect when stressful life events were controlled for. Being female was a common risk factor for poorer positive and increased negative affect. Satisfaction with friendships and a cultural or ethnic identity that is either bicultural or more American were predictive of greater positive affect. Greater religiosity and increased mastery were resources predicting less negative affect. Cognitive and structural interventions that increase opportunities for social integration, increasing mastery, and addressing spiritual concerns are discussed as ways of coping with stress to improve the well-being of individuals in this immigrant community.

  16. KINEMATICS AND DYNAMICS MODELS OF CYLINDRICAL ROLLER BEARING OF RAILWAY TRANSPORT

    Directory of Open Access Journals (Sweden)

    A. V. Gaydamaka

    2014-05-01

    Full Text Available Purpose. Lack of kinematics models and imperfection of the known dynamics models of the roller bearings of railway rolling stock axle-boxes do not allow designing the optimal structure of bearing cages, providing the required service life and reliability of bearing units of wheel sets for cars and locomotives. The studies of kinematics and dynamics of roller bearings of axle boxes for cars and locomotives and modeling of their parts interaction to create the analytical method of bearing cages calculation are necessary. Methodology. This purpose has been achieved due to the modeling of kinematics of the ideal (without gaps and real (taking account the gaps, manufacturing and installation errors bearings, substantiation of the transfer mechanism of motion from the rollers to bearing cage, modeling the dynamics of rolling, research of interaction forces of the rollers with bearing cage. Findings. It is established that the kinematics of ideal bearing is determined by the contact deformations of the rollers and rings, when the kinematics of real bearing depends mainly on the side gaps in the windows of the bearing cage. On the basis of studies of the real bearing kinematics the dynamics models of the rollers and bearing cage interaction were constructed. The conducted studies of kinematics and dynamics of rolling bearings have changed our view of them as of the planetary mechanism, explained the reason of bearing cage loading, and confirmed the possibility of destruction during operation. Originality. It was first proposed a mechanism for motion transfer from the rollers to the bearing cage of roller bearings, consisting in that the side gap in the bearing cage window is reduced gradually multiple of the number of rollers of radial loading area according to the bearing cage motion. The models of roller bearing dynamics, which allow calculating the interaction forces of parts for all modes of operation, were improved. Practical value. Use of the

  17. Computational design of rolling bearings

    CERN Document Server

    Nguyen-Schäfer, Hung

    2016-01-01

    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  18. Job stress and locus of control in teachers: comparisons between samples from the United States and Zimbabwe

    Science.gov (United States)

    Crothers, Laura M.; Kanyongo, Gibbs Y.; Kolbert, Jered B.; Lipinski, John; Kachmar, Steven P.; Koch, Gary D.

    2010-12-01

    This study examines the relationship between educators' locus of control and job stress using samples from the US and Zimbabwe. Multiple regression analyses are used to identify significant relationships in the US sample between teachers' external locus of control and the severity of the job stress that they experience, coupled with the perceived degree of organisational support received. However, this relationship between the locus of control and stress indices could not be identified for the Zimbabwean sample. Significant differences between the two samples were noted in terms of educators' perceptions of the frequency of poor organisational support, with the Zimbabwean teachers reporting greater dissatisfaction. To explain these differences, a qualitative approach was utilised to illuminate the contextual stressors that educators face in Zimbabwe. The implications for teacher preparation measures are discussed.

  19. Allogenic sedimentary components of Bear Lake, Utah and Idaho

    Science.gov (United States)

    Rosenbaum, J.G.; Dean, W.E.; Reynolds, R.L.; Reheis, M.C.

    2009-01-01

    Bear Lake is a long-lived lake filling a tectonic depression between the Bear River Range to the west and the Bear River Plateau to the east, and straddling the border between Utah and Idaho. Mineralogy, elemental geochemistry, and magnetic properties provide information about variations in provenance of allogenic lithic material in last-glacial-age, quartz-rich sediment in Bear Lake. Grain-size data from the siliciclastic fraction of late-glacial to Holocene carbonate-rich sediments provide information about variations in lake level. For the quartz-rich lower unit, which was deposited while the Bear River fl owed into and out of the lake, four source areas are recognized on the basis of modern fluvial samples with contrasting properties that reflect differences in bedrock geology and in magnetite content from dust. One of these areas is underlain by hematite-rich Uinta Mountain Group rocks in the headwaters of the Bear River. Although Uinta Mountain Group rocks make up a small fraction of the catchment, hematite-rich material from this area is an important component of the lower unit. This material is interpreted to be glacial fl our. Variations in the input of glacial flour are interpreted as having caused quasi-cyclical variations in mineralogical and elemental concentrations, and in magnetic properties within the lower unit. The carbonate-rich younger unit was deposited under conditions similar to those of the modern lake, with the Bear River largely bypassing the lake. For two cores taken in more than 30 m of water, median grain sizes in this unit range from ???6 ??m to more than 30 ??m, with the coarsest grain sizes associated with beach or shallow-water deposits. Similar grain-size variations are observed as a function of water depth in the modern lake and provide the basis for interpreting the core grain-size data in terms of lake level. Copyright ?? 2009 The Geological Society of America.

  20. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  1. Recent state of stress change in the Walker Lane zone, western Basin and Range province, United States

    Science.gov (United States)

    Bellier, Olivier; Zoback, Mary Lou

    1995-06-01

    The NW to north-trending Walker Lane zone (WLZ) is located along the western boundary of the northern Basin and Range province with the Sierra Nevada. This zone is distinguished from the surrounding Basin and Range province on the basis of irregular topography and evidence for both normal and strike-slip Holocene faulting. Inversion of slip vectors from active faults, historic fault offsets, and earthquake focal mechanisms indicate two distinct Quaternary stress regimes within the WLZ, both of which are characterized by a consistent WNW σ3 axis; these are a normal faulting regime with a mean σ3 axis of N85°±9°W and a mean stress ratio (R value) (R=(σ2-σ1)/(σ3-σ1)) of 0.63-0.74 and a younger strike-slip faulting regime with a similar mean σ3 axis (N65° - 70°W) and R values ranging between ˜ 0.1 and 0.2. This younger regime is compatible with historic fault offsets and earthquake focal mechanisms. Both the extensional and strike-slip stress regimes reactivated inherited Mesozoic and Cenozoic structures and also produced new faults. The present-day strike-slip stress regime has produced strike-slip, normal oblique-slip, and normal dip-slip historic faulting. Previous workers have explained the complex interaction of active strike-slip, oblique, and normal faulting in the WLZ as a simple consequence of a single stress state with a consistent WNW σ3 axis and transitional between strike-slip and normal faulting (maximum horizontal stress approximately equal to vertical stress, or R ≈ 0 in both regimes) with minor local fluctuations. The slip data reported here support previous results from Owens Valley that suggest deformation within temporally distinct normal and strike-slip faulting stress regimes with a roughly constant WNW trending σ3 axis (Zoback, 1989). A recent change from a normal faulting to a strike-slip faulting stress regime is indicated by the crosscutting striae on faults in basalts the dominantly strike-slip earthquake focal mechanisms and

  2. Radioactivity and the French uranium bearing minerals

    International Nuclear Information System (INIS)

    Guiollard, P.Ch.; Boisson, J.M.; Leydet, J.C.; Meisser, N.

    1998-01-01

    This special issue of Regne Mineral journal is entirely devoted to the French uranium mining industry. It comprises 4 parts dealing with: the uranium mining industry in France (history, uranium rush, deposits, geologic setting, prosperity and recession, situation in 1998, ore processing); radioactivity and the uranium and its descendants (discovery, first French uranium bearing ores, discovery of radioactivity, radium and other uranium descendants, radium mines, uranium mines, atoms, elements and isotopes, uranium genesis, uranium decay, isotopes in an uranium ore, spontaneous fission, selective migration of radionuclides, radon in mines and houses, radioactivity units, radioprotection standards, new standards and controversies, natural and artificial radioactivity, hazards linked with the handling and collecting of uranium ores, conformability with radioprotection standards, radioactivity of natural uranium minerals); the French uranium bearing minerals (composition, crystal structure, reference, etymology, fluorescence). (J.S.)

  3. Hydrostatic and hybrid bearing design

    CERN Document Server

    Rowe, W B

    1983-01-01

    Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

  4. RELATIONSHIP BETWEEN ROLLING AND SLIP RESISTANCE IN ROLLING BEARINGS

    Directory of Open Access Journals (Sweden)

    L. M. Bondarenko

    2016-06-01

    Full Text Available Purpose. About one of the causes of slip rolling is known from the second half of the 19th century, it was believed that the slip resistance appears at the place of contact due to different speeds on the arc of contact. Only in the mid-20th century it was proved that this resistance is negligible in rolling resistance. However (for some unknown reason it is ignored the fact that in practice in rolling bearings may rotate both the inner ring with a stationary outer one, and vice versa almost in equal relations. It is not taken into account the fact that the ball or roller in the rolling bearings runs the different distance along the roller path of the outer and inner bearing cages in one revolution. This fact is not taken into account in determining the calculated values for the friction coefficient of a rolling bearing reduced to the shaft. Therefore, the aim of this work is to determine the influence of path length on the track riding the outer and inner race of the bearing on the determination of the calculated value of the coefficient of friction of rolling bearings is given to the shaft. Methodology. The solution technique is based on the theory of plane motion of a rigid body, the theory of Hertzian contact deformation and the analytical dependencies for determination of coefficient of rolling friction. Findings. The obtained dependences on determination of rolling resistance of the balls or rollers along the bearing tracks of inner and outer bearing cages as well as path difference metering of the rolling on them allows to analytically obtain the rolling resistance and slipping for any size of bearings and different devices of bearing units. It is also possible at the design stage of rolling nodes to handle not only the design but also the content of the node. Originality. Using the analytical dependences for determination of the rolling resistance of bodies at point and line contacts, and also account for the difference in the path of the

  5. Surgical stress response and the potential role of preoperative glucocorticoids on post-anesthesia care unit recovery

    DEFF Research Database (Denmark)

    Steinthorsdottir, Kristin J; Kehlet, Henrik; Aasvang, Eske K

    2017-01-01

    The immediate postoperative course in the post-anesthesia care unit (PACU) remains a challenge across surgical procedures. Postoperative pain, sedation/cognitive dysfunction, nausea and vomiting (PONV), circulatory and respiratory problems and orthostatic intolerance constitute the bulk of the di......-anesthesia care unit (PACU), but with a scarcity of intervention studies using glucocorticoids to control inflammation. We, therefore, suggest a future research focus on the role of inflammation and effect of glucocorticoids in the PACU setting to improve patient recovery....

  6. The legislatio policy and practice concerning the prevention of stress atwork in the Netherlands, United Kingdom, Germany and France

    NARCIS (Netherlands)

    Gier, E. de; Kompier, M.; Draaisma, D.; Smulders, P.G.W.

    1994-01-01

    Last year, at the request of the Directorate-General of Labour of the Dutch Ministry of Social Affairs and Employment, TNO Institute of Preventive Health Care (NIPG) carried out an investigative, qualitative survey of the legislation, policy and practices concerning prevention of stress at work in

  7. Strength Estimation for Hydrate-Bearing Sediments From Direct Shear Tests of Hydrate-Bearing Sand and Silt

    Science.gov (United States)

    Liu, Zhichao; Dai, Sheng; Ning, Fulong; Peng, Li; Wei, Houzhen; Wei, Changfu

    2018-01-01

    Safe and economic methane gas production, as well as the replacement of methane while sequestering carbon in natural hydrate deposits, requires enhanced geomechanical understanding of the strength and volume responses of hydrate-bearing sediments during shear. This study employs a custom-made apparatus to investigate the mechanical and volumetric behaviors of carbon dioxide hydrate-bearing sediments subjected to direct shear. The results show that both peak and residual strengths increase with increased hydrate saturation and vertical stress. Hydrate contributes mainly the cohesion and dilatancy constraint to the peak strength of hydrate-bearing sediments. The postpeak strength reduction is more evident and brittle in specimens with higher hydrate saturation and under lower stress. Significant strength reduction after shear failure is expected in silty sediments with high hydrate saturation Sh ≥ 0.65. Hydrate contribution to the residual strength is mainly by increasing cohesion at low hydrate saturation and friction at high hydrate saturation. Stress state and hydrate saturation are dominating both the stiffness and the strength of hydrate-bearing sediments; thus, a wave velocity-based peak strength prediction model is proposed and validated, which allows for precise estimation of the shear strength of hydrate-bearing sediments through acoustic logging data. This method is advantageous to geomechanical simulators, particularly when the experimental strength data of natural samples are not available.

  8. MODELLING OF THERMOELASTIC TRANSIENT CONTACT INTERACTION FOR BINARY BEARING TAKING INTO ACCOUNT CONVECTION

    Directory of Open Access Journals (Sweden)

    Igor KOLESNIKOV

    2016-12-01

    Full Text Available Serviceability of metal-polymeric "dry-friction" sliding bearings depends on many parameters, including the rotational speed, friction coefficient, thermal and mechanical properties of the bearing system and, as a result, the value of contact temperature. The objective of this study is to develop a computational model for the metallic-polymer bearing, determination on the basis of this model temperature distribution, equivalent and contact stresses for elements of the bearing arrangement and selection of the optimal parameters for the bearing system to achieve thermal balance. Static problem for the combined sliding bearing with the account of heat generation due to friction has been studied in [1]; the dynamic thermoelastic problem of the shaft rotation in a single and double layer bronze bearings were investigated in [2, 3].

  9. The Bearing Capacity of Circular Footings in Sand

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars

    2012-01-01

    dependent on the stress level and on the basis of the test results, a non linear Mohr failure criterion has been proposed. This yield criterion has been implemented in a finite element program and an analysis of the bearing capacity of a circular shaped model foundation, diameter 100mm, has been conducted...

  10. Stress revisited: A critical evaluation of the stress concept

    NARCIS (Netherlands)

    Koolhaas, J.M.; Bartolomucci, A.; Buwalda, B.; de Boer, S.F.; Flügge, G.; Korte, S.M.; Meerloo, P.; Murison, R.; Olivier, B.; Palanza, P.; Richter-Levin, G.; Sgoifo, A.; Steimer, T.; Stiedl, O.; van Dijk, G.; Wöhr, M.; Fuchs, E.

    2011-01-01

    With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely

  11. Stress revisited : a critical evaluation of the stress concept

    NARCIS (Netherlands)

    Koolhaas, J.M.; Bartolomucci, A; Buwalda, B; Flügge, G; de Boer, Sietse; Korte, S M; Meerlo, P; Murison, R; Olivier, B; Palanza, P; Richter-Levin, G; Sgoifo, A; Steimer, T; Stiedl, O; van Dijk, G; Wöhr, M; Fuchs, E

    2011-01-01

    With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely

  12. 75 FR 24545 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Polar Bear...

    Science.gov (United States)

    2010-05-05

    ... Critical Habitat for the Polar Bear in the United States AGENCY: Fish and Wildlife Service, Interior... designation of critical habitat for the polar bear (Ursus maritimus) under the Endangered Species Act of 1973... for the polar bear and on the DEA, and an amended required determinations section of the proposal. We...

  13. Bear-baiting may exacerbate wolf-hunting dog conflict.

    Directory of Open Access Journals (Sweden)

    Joseph K Bump

    Full Text Available BACKGROUND: The influence of policy on the incidence of human-wildlife conflict can be complex and not entirely anticipated. Policies for managing bear hunter success and depredation on hunting dogs by wolves represent an important case because with increasing wolves, depredations are expected to increase. This case is challenging because compensation for wolf depredation on hunting dogs as compared to livestock is less common and more likely to be opposed. Therefore, actions that minimize the likelihood of such conflicts are a conservation need. METHODOLOGY/PRINCIPAL FINDINGS: We used data from two US states with similar wolf populations but markedly different wolf/hunting dog depredation patterns to examine the influence of bear hunting regulations, bear hunter to wolf ratios, hunter method, and hunter effort on wolf depredation trends. Results indicated that the ratio of bear hunting permits sold per wolf, and hunter method are important factors affecting wolf depredation trends in the Upper Great Lakes region, but strong differences exist between Michigan and Wisconsin related in part to the timing and duration of bear-baiting (i.e., free feeding. The probability that a wolf depredated a bear-hunting dog increases with the duration of bear-baiting, resulting in a relative risk of depredation 2.12-7.22× greater in Wisconsin than Michigan. The net effect of compensation for hunting dog depredation in Wisconsin may also contribute to the difference between states. CONCLUSIONS/SIGNIFICANCE: These results identified a potential tradeoff between bear hunting success and wolf/bear-hunting dog conflict. These results indicate that management options to minimize conflict exist, such as adjusting baiting regulations. If reducing depredations is an important goal, this analysis indicates that actions aside from (or in addition to reducing wolf abundance might achieve that goal. This study also stresses the need to better understand the relationship

  14. Bear-baiting may exacerbate wolf-hunting dog conflict.

    Science.gov (United States)

    Bump, Joseph K; Murawski, Chelsea M; Kartano, Linda M; Beyer, Dean E; Roell, Brian J

    2013-01-01

    The influence of policy on the incidence of human-wildlife conflict can be complex and not entirely anticipated. Policies for managing bear hunter success and depredation on hunting dogs by wolves represent an important case because with increasing wolves, depredations are expected to increase. This case is challenging because compensation for wolf depredation on hunting dogs as compared to livestock is less common and more likely to be opposed. Therefore, actions that minimize the likelihood of such conflicts are a conservation need. We used data from two US states with similar wolf populations but markedly different wolf/hunting dog depredation patterns to examine the influence of bear hunting regulations, bear hunter to wolf ratios, hunter method, and hunter effort on wolf depredation trends. Results indicated that the ratio of bear hunting permits sold per wolf, and hunter method are important factors affecting wolf depredation trends in the Upper Great Lakes region, but strong differences exist between Michigan and Wisconsin related in part to the timing and duration of bear-baiting (i.e., free feeding). The probability that a wolf depredated a bear-hunting dog increases with the duration of bear-baiting, resulting in a relative risk of depredation 2.12-7.22× greater in Wisconsin than Michigan. The net effect of compensation for hunting dog depredation in Wisconsin may also contribute to the difference between states. These results identified a potential tradeoff between bear hunting success and wolf/bear-hunting dog conflict. These results indicate that management options to minimize conflict exist, such as adjusting baiting regulations. If reducing depredations is an important goal, this analysis indicates that actions aside from (or in addition to) reducing wolf abundance might achieve that goal. This study also stresses the need to better understand the relationship among baiting practices, the effect of compensation on hunter behavior, and depredation

  15. Superconducting bearings for flywheel applications

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamsen, Asger Bech

    2001-05-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found on the applications of superconducting bearings in flywheels. (au)

  16. Superconducting bearings for flywheel applications

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.

    2001-01-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

  17. Kinematics and early migration in single-radius mobile- and fixed-bearing total knee prostheses

    NARCIS (Netherlands)

    Wolterbeek, N.; Garling, E.H.; Mertens, B.J.; Nelissen, R.G.H.H.; Valstar, E.R.

    2012-01-01

    Background The mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component. This would reduce the contact stresses and wear which in turn may

  18. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  19. Flywheel Challenge: HTS Magnetic Bearing

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2006-01-01

    A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

  20. Early intra-intensive care unit psychological intervention promotes recovery from post traumatic stress disorders, anxiety and depression symptoms in critically ill patients.

    Science.gov (United States)

    Peris, Adriano; Bonizzoli, Manuela; Iozzelli, Dario; Migliaccio, Maria Luisa; Zagli, Giovanni; Bacchereti, Alberto; Debolini, Marta; Vannini, Elisetta; Solaro, Massimo; Balzi, Ilaria; Bendoni, Elisa; Bacchi, Ilaria; Trevisan, Monica; Giovannini, Valtere; Belloni, Laura

    2011-01-01

    Critically ill patients who require intensive care unit (ICU) treatment may experience psychological distress with increasing development of psychological disorders and related morbidity. Our aim was to determine whether intra-ICU clinical psychologist interventions decrease the prevalence of anxiety, depression and posttraumatic stress disorder (PTSD) after 12 months from ICU discharge. Our observational study included critical patients admitted before clinical psychologist intervention (control group) and patients who were involved in a clinical psychologist program (intervention group). The Hospital Anxiety and Depression Scale (HADS) and Impact of Event Scale-Revised questionnaires were used to assess the level of posttraumatic stress, anxiety and depression symptoms. The control and intervention groups showed similar demographic and clinical characteristics. Patients in the intervention group showed lower rates of anxiety (8.9% vs. 17.4%) and depression (6.5% vs. 12.8%) than the control group on the basis of HADS scores, even if the differences were not statistically significant. High risk for PTSD was significantly lower in patients receiving early clinical psychologist support than in the control group (21.1% vs. 57%; P < 0.0001). The percentage of patients who needed psychiatric medications at 12 months was significantly higher in the control group than in the patient group (41.7% vs. 8.1%; P < 0.0001). Our results suggest that that early intra-ICU clinical psychologist intervention may help critically ill trauma patients recover from this stressful experience.

  1. Journal bearing impedance descriptions for rotordynamic applications

    NARCIS (Netherlands)

    Childs, D.W.; Moes, H.; Leeuwen, van H.J.

    1977-01-01

    Bearing impedance vectors are introduced for plain journal bearings which define the bearing reaction force components as a function of the bearing motion. Impedance descriptions are developed directly for the approximate Ocvirk (short) and Sommerfeld (long) bearing solutions. The impedance vector

  2. The paradigm of grizzly bear restoration in North America

    Science.gov (United States)

    Schwartz, C. C.; Maehr, David S.; Noss, Reed F.; Larkin, J.L.

    2002-01-01

    Grizzly bear restoration and recovery is a controversial, highly politicized process. By 1959, when the Craigheads began their pioneering work on Yellowstone grizzly bears, the species had been reduced to a remnant of its historic range. Prior to the colonization of North America by Europeans, the grizzly lived in relatively pristine habitats with aboriginal Native Americans. As civilization expanded, humans changed the face of the landscape, converting grizzly bear habitat to farms and ranches. People killed grizzlies to protect livestock and eliminate a perceived threat to human safety. In concert, habitat loss and direct human-caused mortality had effectively eliminated the grizzly from 95 percent of its historic range in the conterminous United States by the 1920s (Servheen 1989). Grizzly bear numbers had been reduced nearly 98 percent by 1975 when the species was listed as threatened under the Endangered Species Act (ESA) (USFWS 1993).

  3. Diagnosis of bearing creep in wind turbine gearboxes

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Liu, Zhenyan; Hilmisson, Reynir

    2016-01-01

    One of the most wide spread gearbox topologies in the wind energy sector consists of a slow rotating planetary stage, an intermediate speed parallel stage and finally a high speed parallel stage driving the generator rotor. The shafts of the two latter stages are supported by ball or roller...... bearings where their outer races are fixed to the gearbox and their inner races rotate at the corresponding shaft speed. Bearing inner race defects are frequently encountered in gearboxes leading to either replacement of the whole unit or exchange of the shaft or bearing where feasible. The present work...... deals with the evaluation of the development of an inner race defect from surface pitting to race axial crack resulting in excessive rotational looseness, also referred to as bearing creep. It is shown that an inner race defect can be identified efficiently at an early stage by employing well known...

  4. The prevalence of post traumatic stress disorder in an army unit and its relationship with functional gastrointestinal disorders

    Directory of Open Access Journals (Sweden)

    Qian WANG

    2018-04-01

    Full Text Available Objective To determine the prevalence of post traumatic stress disorder (PTSD in the army officers and soldiers (AOSs, and identify its relationship with functional gastrointestinal disorders (FGIDs. Methods PTSD and FGIDs were diagnosed based on the PTSD checklist-civilian (PCL-C and Rome Ⅲ Modular Questionnaire respectively, the overlaps of PTSD and FGIDs and their correlation were diagnosed. The correlation of PTSD with traumatic and stressful events was investigated using Trauma History and Stressful Event Screening Questionnaire. The coexistence and relationship of PTSD and FGIDs were analyzed. Results Of 927 AOSs, 33 were diagnosed with PTSD. The prevalence of PTSD was 3.56%. FGIDs were identified in 435 subjects and the incidence of FGIDs was 46.93%. Among 33 AOSs with PTSD, 28 were diagnosed as having FGIDs and the prevalence of FGIDs was 84.85%, which was significantly higher than that of non-PTSD group (45.53%, P<0.05. Moreover, the FGIDs group had a higher prevalence of PTSD, compared with the non-FGID group (6.43% vs. 1.02%, P<0.05. Cyclic vomiting syndrome (CVS, 33.33%, unspecified functional bowel disorder (24.24%, functional bloating (18.18% and functional anorectal pain (18.18% were the four most frequent FGIDs in PTSD AOSs. Multiple regression analysis showed PTSD was the risk factor for CVS (OR=9.118, functional anorectal pain (OR=3.373, functional bloating (OR=4.772, irritable bowel syndrome (OR=3.438, rumination syndrome (OR=16.033, functional vomiting (OR=10.329, functional dysphagia (OR=9.891(P<0.05. CVS (OR=4.063, the number of traumatic (OR=1.159 and stress events (OR=1.401 were the risk factors for PTSD in AOSs (P<0.05. Conclusions PTSD and FGID interact as risk factor each other. The prevalence of PTSD differs significantly in different FGIDs. CVS is the most frequent FGID in PTSD AOSs and risk factor for PTSD, which deserves more concerns. DOI: 10.11855/j.issn.0577-7402.2018.02.14

  5. Fatigue methodology for life predictions for the wheel-rail contact area in large offshore turret bearings

    Directory of Open Access Journals (Sweden)

    T. Lassen

    2016-10-01

    Full Text Available The present report presents a fatigue life prediction method for large roller bearings applied in the turret turn table for large loading buoy units. The contact points between wheel and rail in these bearings are subjected to a multi-axial fluctuating stress situation and both surface wear and fatigue cracking may occur. A methodology based on the Dang Van fatigue criterion is adopted. The criterion is based on an equivalent stress defined as a combination of the fluctuation of the shear stress from its mean value at a critical plane and the associated hydrostatic stress at the given time. The present work is supporting the theoretical model by extensive laboratory testing. Both full scale testing of wheel on rail and small scale testing for characterizing the steel material are carried out. An experimental program was carried out with the high strength stainless steel S165M. The Dang Van stress concept is applied in combination with the Random Fatigue Limit Method (RFLM for life data analyses. This approach gives the opportunity to include both finite lives and the run-outs in a rational manner without any presumption of the existence of a fatigue limit in advance of the data. This gives a non-linear S-N curve for a log-log scale in the very high cycle regime close to the fatigue limit. It is demonstrated how the scatter in fatigue limit decreases when the Dang Van stress concept is applied and that the fatigue limit is occurring beyond 107 cycles

  6. Eastern slopes grizzly bear project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-01-01

    The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

  7. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  8. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  9. Transient Lift-Off Test Results for an Experimental Hybrid Bearing in Air

    Science.gov (United States)

    2009-12-01

    bearings. The electric motor designed to drive the rotor is a high speed integral motorized spindle unit manufactured by SKF Precision Technologies and...create pressure that supports the rotor ( shaft ) without rotation. The pressure generated by the flow through an orifice gives the hybrid bearing a...Kettering University; Chair of Advisory Committee: Dr. Dara Childs A hybrid bearing designed for use in a next generation turbo-pump is

  10. Bears, Big and Little. Young Discovery Library Series.

    Science.gov (United States)

    Pfeffer, Pierre

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

  11. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic Ball Bearings

    Science.gov (United States)

    DellaCorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2016-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  12. Water-bearing explosive compositions

    Energy Technology Data Exchange (ETDEWEB)

    Gay, G M

    1970-12-21

    An explosive water-bearing composition, with high detonation velocity, comprises a mixture of (1) an inorganic oxidizer salt; (2) nitroglycerine; (3) nitrocellulose; (4) water; and (5) a water thickening agent. (11 claims)

  13. Research on vibration properties of auxiliary bearing cage used in HTR-10 GT project

    International Nuclear Information System (INIS)

    Qin Qingquan; Yang Guojun; Shi Zhengang; Yu Suyuan

    2009-01-01

    Auxiliary Bearings (ABs) is one of the most important parts in Active Magnetic Bearing (AMB) system, which was used in HTR-10 GT project. This paper uses finite element method to analyze the centrifugal stress and free vibration properties of the cage according to its work condition. And different geometric parameters of the cage that has effects on its vibration performance are discussed. The results show that the highest centrifugal stress is in the middle of the cage side sill. The low odder vibration modes of the cage can be induced when the auxiliary bearings are working. Proper geometric parameters and ball pocket number can enhance the performance of the cage. (authors)

  14. Midterm Clinical and Radiographic Results of Mobile-Bearing Revision Total Knee Arthroplasty.

    Science.gov (United States)

    Kim, Raymond H; Martin, J Ryan; Dennis, Douglas A; Yang, Charlie C; Jennings, Jason M; Lee, Gwo-Chin

    2017-06-01

    Constrained implants are frequently required in revision total knee arthroplasty (TKA) and are associated with an increase in aseptic component loosening and damage or wear to the constraining mechanisms, compared with primary TKA. The purpose of the following study was to evaluate the midterm clinical and radiographic results including the incidence of bearing complications in a group of patients undergoing revision TKA using mobile-bearing revision TKA implants. We retrospectively reviewed 316 consecutive mobile-bearing revision TKAs performed at 2 centers between 2006 and 2010. There were 183 women and 133 men with a mean age of 66 years. The patients were evaluated clinically using the Knee Society scores. A radiographic analysis was performed. Bearing specific complications (ie, instability or dislocation) were recorded. Patients were followed-up for a minimum of 24 months and a median of 59.88 months (range 24-121.2). The average Knee Society knee score and function scores increased from 40.8 and 47.9 points preoperatively to 80 points and 70.3 points, respectively (P bearing complications were observed. Revision TKA using mobile-bearing revision components demonstrated favorable midterm clinical and radiographic results with no occurrence of bearing instability or dislocation. Longer follow-up is required to evaluate for potential advantages of mobile-bearings over fixed-bearing revision components in terms of polyethylene wear reduction, reduced stress transmission across fixation interfaces, and reduced stress on the polyethylene post. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Failure analysis of superconducting bearings

    Energy Technology Data Exchange (ETDEWEB)

    Rastogi, Amit; Campbell, A M; Coombs, T A [Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    2006-06-01

    The dynamics of superconductor bearings in a cryogenic failure scenario have been analyzed. As the superconductor warms up, the rotor goes through multiple resonance frequencies, begins to slow down and finally touches down when the superconductor goes through its transition temperature. The bearing can be modelled as a system of springs with axial, radial and cross stiffness. These springs go through various resonant modes as the temperature of the superconductor begins to rise. We have presented possible explanations for such behavio0008.

  16. Superconducting composite for magnetic bearings

    International Nuclear Information System (INIS)

    Rigney, T.K. II.

    1995-01-01

    A composite includes granules of Type II superconducting material and granules of rare-earth permanent magnets that are distributed in a binder. The composite is a two-phase structure that combines the properties of the superconductor and magnets with the flexibility and toughness of a polymeric material. A bearing made from this composite has the load capacity and stiffness of a permanent magnet bearing with added stability from a Type II superconducting material. 7 figs

  17. Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit.

    Science.gov (United States)

    Banks, William A; Gray, Alicia M; Erickson, Michelle A; Salameh, Therese S; Damodarasamy, Mamatha; Sheibani, Nader; Meabon, James S; Wing, Emily E; Morofuji, Yoichi; Cook, David G; Reed, May J

    2015-11-25

    Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain. We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using (14)C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to (14)C-sucrose and radioactive albumin. In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with (14)C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and (14)C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes. The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is

  18. A Study of Static Performance of Fixed Inclined Slider Bearings – A ...

    African Journals Online (AJOL)

    Michael Horsfall

    A Study of Static Performance of Fixed Inclined Slider Bearings – A Power Law Model. 1OLADEINDE, M H; 2EDOKPIA, R O; ... Keyword: power law, slider bearing, finite element, load capacity, pressure. Traditionally, most lubricants are .... The volumetric flow rate per unit width is computed by using the expression shown in ...

  19. Rebuttal of "Polar bear population forecasts: a public-policy forecasting audit"

    Science.gov (United States)

    Steven C. Amstrup; Hal Caswell; Eric DeWeaver; Ian Stirling; David C. Douglas; Bruce G. Marcot; Christine M. Hunter

    2009-01-01

    Observed declines in the Arctic sea ice have resulted in a variety of negative effects on polar bears (Ursus maritimus). Projections for additional future declines in sea ice resulted in a proposal to list polar bears as a threatened species under the United States Endangered Species Act. To provide information for the Department of the Interior...

  20. Experience of the air medical evacuation team of Serbian armed forces in the united nations mission in the Democratic Republic of Congo - deployment stress and psychological adaptation

    Directory of Open Access Journals (Sweden)

    Joković Danilo B.

    2016-01-01

    Full Text Available Background/Aim. Wars of the nineties in former Yugoslavia, Somalia, Rwanda imposed new tasks to the United Nations (UN forces, such as providing humanitarian aid, protection of civilians, peacekeeping, and in many instances providing armed enforcement of peace. The aim of this study was an observational analysis of Serbian participation in the UNs Mission in the Democratic Republic of Congo with the emphasis on stress and coping techniques. Methods. Serbian contribution in this mission dates back to April 2003 till the present days with a military contingent consisting of six members as a part of Air Medical Evacuation Team. The observed stressogenous factors acted before arrival to the mission area and in the mission area. In this paper we analysed ways to overcome them. Results. The productive ways of overwhelming stress used in this mission were: honesty and openness in interpersonal communications, dedication to work, maintaining discipline and order, strict following of appropriate regime of work, diet, rest and recreation; regular communication with family and organizing and participation in various social, cultural and sports manifestations. Conclusion. This analysis indicates that out of all the observed factors, the most important is appropriate selection of personnel.

  1. The Effects of Kangaroo Care in the Neonatal Intensive Care Unit on the Physiological Functions of Preterm Infants, Maternal-Infant Attachment, and Maternal Stress.

    Science.gov (United States)

    Cho, Eun-Sook; Kim, Shin-Jeong; Kwon, Myung Soon; Cho, Haeryun; Kim, Eun Hye; Jun, Eun Mi; Lee, Sunhee

    2016-01-01

    This study was conducted to identify the effects of kangaroo care on the physiological functions of preterm infants, maternal-infant attachment, and maternal stress. For this study, a quasi-experiment design was used with a nonequivalent control group, and a pre- and post-test. Data were collected from preterm infants with corrected gestational ages of ≥33weeks who were hospitalized between May and October 2011. Twenty infants were assigned to the experimental group and 20 to the control group. As an intervention, kangaroo care was provided in 30-min sessions conducted thrice a week for a total of 10 times. The collected data were analyzed by using the t test, repeated-measures ANOVA, and the ANCOVA test. After kangaroo care, the respiration rate significantly differed between the two groups (F=5.701, p=.020). The experimental group had higher maternal-infant attachment scores (F=25.881, pinfant physiological functions such as respiration rate, increasing maternal-infant attachment, and reducing maternal stress. This study suggests that kangaroo care can be used to promote emotional bonding and support between mothers and their babies, and to stabilize the physiological functions of premature babies. Kangaroo care may be one of the most effective nursing interventions in the neonatal intensive care unit for the care of preterm infants and their mothers. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Spatially explicit estimation of heat stress-related impacts of climate change on the milk production of dairy cows in the United Kingdom

    Science.gov (United States)

    Topp, Cairistiona F. E.; Moorby, Jon M.; Pásztor, László; Foyer, Christine H.

    2018-01-01

    Dairy farming is one the most important sectors of United Kingdom (UK) agriculture. It faces major challenges due to climate change, which will have direct impacts on dairy cows as a result of heat stress. In the absence of adaptations, this could potentially lead to considerable milk loss. Using an 11-member climate projection ensemble, as well as an ensemble of 18 milk loss estimation methods, temporal changes in milk production of UK dairy cows were estimated for the 21st century at a 25 km resolution in a spatially-explicit way. While increases in UK temperatures are projected to lead to relatively low average annual milk losses, even for southern UK regions (cow), the ‘hottest’ 25×25 km grid cell in the hottest year in the 2090s, showed an annual milk loss exceeding 1300 kg/cow. This figure represents approximately 17% of the potential milk production of today’s average cow. Despite the potential considerable inter-annual variability of annual milk loss, as well as the large differences between the climate projections, the variety of calculation methods is likely to introduce even greater uncertainty into milk loss estimations. To address this issue, a novel, more biologically-appropriate mechanism of estimating milk loss is proposed that provides more realistic future projections. We conclude that South West England is the region most vulnerable to climate change economically, because it is characterised by a high dairy herd density and therefore potentially high heat stress-related milk loss. In the absence of mitigation measures, estimated heat stress-related annual income loss for this region by the end of this century may reach £13.4M in average years and £33.8M in extreme years. PMID:29738581

  3. Spatially explicit estimation of heat stress-related impacts of climate change on the milk production of dairy cows in the United Kingdom.

    Directory of Open Access Journals (Sweden)

    Nándor Fodor

    Full Text Available Dairy farming is one the most important sectors of United Kingdom (UK agriculture. It faces major challenges due to climate change, which will have direct impacts on dairy cows as a result of heat stress. In the absence of adaptations, this could potentially lead to considerable milk loss. Using an 11-member climate projection ensemble, as well as an ensemble of 18 milk loss estimation methods, temporal changes in milk production of UK dairy cows were estimated for the 21st century at a 25 km resolution in a spatially-explicit way. While increases in UK temperatures are projected to lead to relatively low average annual milk losses, even for southern UK regions (<180 kg/cow, the 'hottest' 25×25 km grid cell in the hottest year in the 2090s, showed an annual milk loss exceeding 1300 kg/cow. This figure represents approximately 17% of the potential milk production of today's average cow. Despite the potential considerable inter-annual variability of annual milk loss, as well as the large differences between the climate projections, the variety of calculation methods is likely to introduce even greater uncertainty into milk loss estimations. To address this issue, a novel, more biologically-appropriate mechanism of estimating milk loss is proposed that provides more realistic future projections. We conclude that South West England is the region most vulnerable to climate change economically, because it is characterised by a high dairy herd density and therefore potentially high heat stress-related milk loss. In the absence of mitigation measures, estimated heat stress-related annual income loss for this region by the end of this century may reach £13.4M in average years and £33.8M in extreme years.

  4. Reported incidence and precipitating factors of work-related stress and mental ill-health in the United Kingdom (1996-2001).

    Science.gov (United States)

    Cherry, Nicola M; Chen, Yiqun; McDonald, J Corbett

    2006-09-01

    Work-related mental ill-health appears to be increasing. Population-based data on incidence are scarce but in the United Kingdom occupational physicians and psychiatrists report these conditions to voluntary surveillance schemes. To estimate the incidence of work-related stress and mental illness reported 1996-2001 by occupational physicians and 1999-2001 by psychiatrists. Estimated annual average incidence rates were calculated by sex, occupation and industry against appropriate populations at risk. An in-house coding scheme was used to classify and analyse data on precipitating events. An estimated annual average of 3,624 new cases were reported by psychiatrists, and 2,718 by occupational physicians; the rates were higher for men in reports based on the former and for women on the latter. Most diagnoses were of anxiety/depression or work-related stress, with post-traumatic stress accounting for approximately 10% of cases reported by psychiatrists. High rates of ill-health were seen among professional and associated workers and in those in personal and protective services. Factors (such as work overload) intrinsic to the job and issues with interpersonal relations were the most common causes overall. The steep increase in new cases of work-related mental ill-health reported by occupational physicians since 1996 may reflect a greater willingness by workers to seek help but may also signify an increasing dissonance between workers' expectations and the work environment. Greater expertise is needed to improve the workplace by adjustment of job demands, improvement of working relations, increasing workers' capacities and management of organizational change.

  5. Prediction of equibiaxial loading stress in collagen-based extracellular matrix using a three-dimensional unit cell model.

    Science.gov (United States)

    Susilo, Monica E; Bell, Brett J; Roeder, Blayne A; Voytik-Harbin, Sherry L; Kokini, Klod; Nauman, Eric A

    2013-03-01

    Mechanical signals are important factors in determining cell fate. Therefore, insights as to how mechanical signals are transferred between the cell and its surrounding three-dimensional collagen fibril network will provide a basis for designing the optimum extracellular matrix (ECM) microenvironment for tissue regeneration. Previously we described a cellular solid model to predict fibril microstructure-mechanical relationships of reconstituted collagen matrices due to unidirectional loads (Acta Biomater 2010;6:1471-86). The model consisted of representative volume elements made up of an interconnected network of flexible struts. The present study extends this work by adapting the model to account for microstructural anisotropy of the collagen fibrils and a biaxial loading environment. The model was calibrated based on uniaxial tensile data and used to predict the equibiaxial tensile stress-stretch relationship. Modifications to the model significantly improved its predictive capacity for equibiaxial loading data. With a comparable fibril length (model 5.9-8μm, measured 7.5μm) and appropriate fibril anisotropy the anisotropic model provides a better representation of the collagen fibril microstructure. Such models are important tools for tissue engineering because they facilitate prediction of microstructure-mechanical relationships for collagen matrices over a wide range of microstructures and provide a framework for predicting cell-ECM interactions. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Density of American black bears in New Mexico

    Science.gov (United States)

    Gould, Matthew J.; Cain, James W.; Roemer, Gary W.; Gould, William R.; Liley, Stewart

    2018-01-01

    Considering advances in noninvasive genetic sampling and spatially explicit capture–recapture (SECR) models, the New Mexico Department of Game and Fish sought to update their density estimates for American black bear (Ursus americanus) populations in New Mexico, USA, to aide in setting sustainable harvest limits. We estimated black bear density in the Sangre de Cristo, Sandia, and Sacramento Mountains, New Mexico, 2012–2014. We collected hair samples from black bears using hair traps and bear rubs and used a sex marker and a suite of microsatellite loci to individually genotype hair samples. We then estimated density in a SECR framework using sex, elevation, land cover type, and time to model heterogeneity in detection probability and the spatial scale over which detection probability declines. We sampled the populations using 554 hair traps and 117 bear rubs and collected 4,083 hair samples. We identified 725 (367 male, 358 female) individuals. Our density estimates varied from 16.5 bears/100 km2 (95% CI = 11.6–23.5) in the southern Sacramento Mountains to 25.7 bears/100 km2 (95% CI = 13.2–50.1) in the Sandia Mountains. Overall, detection probability at the activity center (g0) was low across all study areas and ranged from 0.00001 to 0.02. The low values of g0 were primarily a result of half of all hair samples for which genotypes were attempted failing to produce a complete genotype. We speculate that the low success we had genotyping hair samples was due to exceedingly high levels of ultraviolet (UV) radiation that degraded the DNA in the hair. Despite sampling difficulties, we were able to produce density estimates with levels of precision comparable to those estimated for black bears elsewhere in the United States.

  7. The Role of Coping in Moderating the Relationship between Racism-Related Stress and Self-Reported General Health among Asians and Latinas/os in the United States

    OpenAIRE

    Castro, Denise Carina

    2017-01-01

    Previous research has shown an association between racism-related stress and negative health outcomes among African Americans and the moderating effect of coping strategies on this relationship. Yet, scant attention has been paid to this relationship for two of the largest minority groups in the United States: Asians and Latinos/as. Using the 2009 California Health Interview Survey (CHIS) and a framework derived from stress process and biopsychosocial models, this study examines the relation...

  8. Transtorno de estresse pós-traumático em pacientes de unidade de terapia intensiva Post-traumatic stress disorder in intensive care unit patients

    Directory of Open Access Journals (Sweden)

    Andrea Vannini Santesso Caiuby

    2010-03-01

    Full Text Available O transtorno de estresse pós-traumático tem sido descrito em pacientes após tratamento em unidade de terapia intensiva. O objetivo foi revisar estudos sobre os aspectos psicológicos e as intervenções terapêuticas destes pacientes após internação em unidade de terapia intensiva. Trinta e oito artigos foram incluídos. A prevalência de transtorno de estresse pós-traumático variou de 17% a 30% e a incidência de 14% a 24%. Os fatores de risco foram: história prévia de ansiedade, depressão ou pânico, ter memórias traumáticas ilusórias (memórias derivadas de formações psíquicas como sonho e delirium, tempo de ventilação mecânica, experiências estressantes, crenças e comportamentos de característica depressiva. Doses altas de opióides, sintomas na retirada da sedação ou analgesia e o uso de lorazepam foram relacionados ao aumento de delirium e de memória ilusória. A sintomatologia do transtorno pode ser reduzida com a administração de hidrocortisona, com a interrupção diária da sedação e não foram encontrados estudos de efetividade de intervenção psicológica.Post-traumatic stress disorder has been detected in patients after treatment in intensive care unit. The main goal of this study is to review the psychological aspects and therapeutic interventions on those patients after their treatment on intensive care unit. Thirty eight articles have been included. The prevalence of post-traumatic stress disorder has varied from 17% up to 30% and the incidence from 14% to 24%. The risk factors were: previous anxiety historic, depression or panic, having delusional traumatic memories (derived from psychic formations as dreams and delirium, belief effects, depressive behavior, stressing experiences and mechanical ventilation. High doses of opiates, symptoms caused by sedation or analgesia reduction and the use of lorazepam were related with the increase of delirium and delusional memory. The disorder sintomatology

  9. Niveles de estrés en el personal de enfermería de unidades de cuidados paliativos Stress levels on nursing staff of palliative care units

    Directory of Open Access Journals (Sweden)

    Cristina Gómez Cantorna

    2012-06-01

    Full Text Available Mediante este estudio, nos gustaría saber cuál es el nivel de estrés que padecen las enfermeras, que trabajan en unidades de cuidados paliativos. Para ello hemos elegido una muestra de 94 enfermeras del SERGAS (Servicio Galego de Saúde, de las distintas unidades de cuidados paliativos, utilizando un cuestionario de datos sociodemográficos y organizacionales junto con el Maslach Burnout Inventory, como instrumentos evaluatorios. Después del análisis de los datos observamos que el personal de enfermería que trabaja en dichas unidades de cuidados paliativos, no presenta un nivel de estrés tan elevado como el que nosotros planteábamos al principio de nuestro estudio.Through this study, we would like to know what level of stress experienced by nurses working in palliative care units. We have chosen a sample of 94 nurses of SERGAS (Servicio Galego de las Saúde of the different palliative care units, using a questionnaire on demographic and organizational data with the Maslach Burnout Inventory, for assessment tools. After analyzin the dat we note that the nursing staff working in this departament of palliative care, no estres levels as high as we posed at the beginning of our study.

  10. 49 CFR 229.69 - Side bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in...

  11. Superconductor bearings, flywheels and transportation

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Rothfeld, R; Riedel, T; Goebel, B; Wippich, D; Schirrmeister, P

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS–FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN 2 . More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  12. Magnetic bearing flywheels for electric storage

    Energy Technology Data Exchange (ETDEWEB)

    Poubeau, P C

    1981-01-01

    A magnetic bearing flywheel was designed. In order to have a simple, reliable system, magnetic suspension with a single servoloop for one degree of freedom of the rotor was used, four other degrees of freedom being controlled passively and the sixth one, corresponding to the rotation axis. The motor that transfers electric energy to the rotor is of the ironless brushless dc type with electronic commutation. It is operated alternatively for accelerating the wheel and then as a generator for delivering the stored energy. The use of high stress composite materials in the rotor greatly increases the operational limits of this equipment. Key characteristics of kinetic energy storage are mentioned along with a wide range of applications. Besides energy storage for satellites, these include power smoothing for solar and wind energy systems as well as backup power supplies, e.g., for electric vehicles.

  13. Noise estimation of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2003-01-01

    Noise estimating procedures of oil lubricated journal bearings are presented. Nonlinear analysis of rotor-bearing system including unbalance mass of the rotor is performed in order to obtain acoustical properties of the bearing. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Noise estimating procedures presented in this paper could aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  14. Adaptação cultural e validação para a língua portuguesa da Parental Stress Scale: Neonatal Intensive Care Unit (PSS:NICU Adaptación cultural y validación al idioma português del Parental Stress Scale: Neonatal Intensive Care Unit (PSS:NICU Cultural adaptation and validation for the portuguese language of the Parental Stress Scale: Neonatal Intensive Care Unit (PSS:NICU

    Directory of Open Access Journals (Sweden)

    Sandra Regina de Souza

    2012-01-01

    Full Text Available OBJETIVO: Traduzir, realizar a adaptação cultural e validar a escala Parental Stress Scale:Neonatal Intensive Care Unit (PSS:NICU para a língua portuguesa. MÉTODOS: Utilizou-se o método descritivo de validação de instrumentos de medida, baseado nas etapas propostas por Guillemin et al. A análise da confiabilidade foi realizada por meio dos testes e retestes e da consistência interna. Na validação clínica, participaram 163 pais de recém-nascidos internados em Unidade de Terapia Intensiva Neonatal (UTIN. RESULTADOS: Os coeficientes de correlação intraclasse ficaram em torno de 0,70 mostrando boa estabilidade entre as duas avaliações. A análise fatorial pelo método de componentes principais utilizou os mesmos critérios da escala original, com rotação Varimax, com grau de variância adequado de 57,9%. Os maiores níveis de estresse dos pais foram obtidos na subescala "alteração do papel de pais". CONCLUSÃO: A PSS:NICU na versão em português é uma ferramenta válida e confiável para avaliação do estresse de pais com filho internado na UTIN.OBJETIVO: Traducir, realizar la adaptación cultural y validar la escala Parental Stress Scale:Neonatal Intensive Care Unit (PSS:NICU al idioma portugués. MÉTODOS: Se utilizó el método descriptivo de validación de instrumentos de medida, basado en las etapas propuestas por Guillemin et al. El análisis de la confiabilidad fue realizado por medio de los tests y retests y de la consistencia interna. En la validación clínica, participaron 163 padres de recién nacidos internados en una Unidad de Cuidados Intensivos Neonatal (UCIN. RESULTADOS: Los coeficientes de correlación intraclase quedaron alrededor de 0,70 mostrando buena estabilidad entre las dos evaluaciones El análisis factorial por el método de componentes principales utilizó los mismos criterios de la escala original, con rotación Varimax, con grado de varianza adecuado de 57,9%. Los mayores niveles de estrés de

  15. Design and Operating Characteristics of High-Speed, Small-Bore, Angular-Contact Ball Bearings

    Science.gov (United States)

    Pinel, Stanley I.; Signer, Hans R.; Zaretsky, Erwin V.

    1998-01-01

    The computer program SHABERTH was used to analyze 35-mm-bore, angular-contact ball bearings designed and manufactured for high-speed turbomachinery applications. Parametric tests of the bearings were conducted on a high-speed, high-temperature bearing tester and were compared with the computer predictions. Four bearing and cage designs were studied. The bearings were lubricated either by jet lubrication or through the split inner ring with and without outer-ring cooling. The predicted bearing life decreased with increasing speed because of increased operating contact stresses caused by changes in contact angle and centrifugal load. For thrust loads only, the difference in calculated life for the 24 deg. and 30 deg. contact-angle bearings was insignificant. However, for combined loading, the 24 deg. contact-angle bearing gave longer life. For split-inner-ring bearings, optimal operating conditions were obtained with a 24 deg. contact angle and an inner-ring, land-guided cage, using outer-ring cooling in conjunction with low lubricant flow rates. Lower temperature and power losses were obtained with a single-outer-ring, land-guided cage for the 24 deg. contact-angle bearing having a relieved inner ring and partially relieved outer ring. Inner-ring temperatures were independent of lubrication mode and cage design. In comparison with measured values, reasonably good engineering correlation was obtained using the computer program SHABERTH for predicted bearing power loss and for inner- and outer-ring temperatures. The Parker formula for XCAV (used in SHABERTH, a measure of oil volume in the bearing cavity) may need to be refined to reflect bearing lubrication mode, cage design, and location of cage-controlling land.

  16. Remedial Investigation work plan for Bear Creek Valley Operable Unit 2 (Rust Spoil Area, SY-200 Yard, Spoil Area 1) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1992-09-01

    This Remedial Investigation (RI) work plan contains summaries of geographical, historical, operational, geological, and hydrological information specific to the unit. The potential for release of contamination to receptors through the various media is addressed, and a sampling and analysis plan is presented to determine the extent of release of contamination to the surrounding environment. Proposed activities include walkover radiation surveys at all sites, soil borings at SY-200, piezometer installation and water table sampling at SA-1 and SY-200, and surface water and sediment runoff sampling at all three sites. Data from the site characterization activities will be combined with data from ongoing site-wide monitoring programs (i.e., groundwater, surface water, and biological monitoring) to provide input for a screening-level risk assessment and evaluation of altemative remedial actions

  17. Changes in plain bearing technology

    CERN Document Server

    Koring, Rolf

    2012-01-01

    A unique fusion of theoretical and practical knowledge, Changes in Plain Bearing Technology, by Rolf Koring, covers a meaningful range of expertise in this field.Drawing from years of experience in design development, materials selection, and their correlation to real-life part failure, this title, co-published by SAE International and expert Verlag (Germany), concentrates on hydrodynamic bearings lined with white metals, also known as Babbits.Written under the assumption that even the most mature body of knowledge can be revisited and improved, Changes in Plain Bearing Technology is a courageous and focused approach to questioning accepted test results and looking at alternative material compounds, and their application suitability.The process, which leads to innovative answers on how the technology is transforming itself to respond to new market requirements, shows how interdisciplinary thinking can recognize new potential in long-established industrial modus operandi.Tackling the highly complex issue of co...

  18. 'Dodo' and 'Baby Bear' Trenches

    Science.gov (United States)

    2008-01-01

    NASA's Phoenix Mars Lander's Surface Stereo Imager took this image on Sol 11 (June 5, 2008), the eleventh day after landing. It shows the trenches dug by Phoenix's Robotic Arm. The trench on the left is informally called 'Dodo' and was dug as a test. The trench on the right is informally called 'Baby Bear.' The sample dug from Baby Bear will be delivered to the Phoenix's Thermal and Evolved-Gas Analyzer, or TEGA. The Baby Bear trench is 9 centimeters (3.1 inches) wide and 4 centimeters (1.6 inches) deep. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  19. Development of design method of thick rubber bearings for three-dimensional base isolation

    International Nuclear Information System (INIS)

    Yabana, Shuichi; Matuda, Akihiro

    2000-01-01

    Thick rubber bearings as 3-dimensional base isolators have been developed to reduce both horizontal and vertical seismic loads especially for equipment in Fast Breeder Reactors. In this report, a design method of thick rubber bearings is presented. To consider nonlinearity of vertical stiffness affected by vertical stress in the design of thick rubber bearings, Lindley's evaluation method of vertical stiffness is modified as an explicit form of vertical stress. We confirm that the presented method is efficient for design of the thick rubber bearings from comparing between test results and predicted values. Furthermore, rubber bearing tests are conducted with 1/3 scale models to evaluate mechanical properties of thick rubber bearings including ultimate limits. In the tests, horizontal and vertical characteristics of 1/3 scale model are compared with those of 1/6 scale model to discuss scale effect of test specimen. Ultimate limits such as failure shear strain of thick rubber bearings are obtained under various loading conditions. From the test results, we confirm that full scale thick rubber bearing to satisfy requirements is feasible. (author)

  20. Mechatronics Applied to Fluid Film Bearings: Towards More Efficient Machinery

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier

    the machine is defined as a mechatronic system. This integrated approach comprises the usage of machine elements capable of modifying their characteristics, by using in a combined way mechanical elements, sensors, processing units and actuators. The research project entitled "Mechatronics Applied to Fluid......The current trends regarding turbomachinery design and operation demand for an expansion of the operational boundaries of these mechanical systems, regarding production rate, reliability and adaptability. In order to face the new requirements, it is necessary to migrate towards a new concept, where...... Film Bearings: Towards more Efficient Machinery" was aimed at improving the state of the art regarding the usage of fluid film bearings as "smart" machine elements. Specifically, this project dealt with a tilting pad journal bearing design that features a controllable lubrication system, capable...

  1. How to Stop the Bear: Strategy of Small States

    Science.gov (United States)

    2010-12-01

    stressing the role of international law, and abstentionism from security alliance” (George J. Stein, 1990, p. 4). At the same time, the Dutch were reluctant...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited HOW TO STOP THE BEAR...estimated to average 1 hour per response, including the time for reviewing instruction, searching existing data sources, gathering and maintaining

  2. Performance assessment of auxiliary bearing in HTR-10 AMB helium circulator on the event of rotor drop

    International Nuclear Information System (INIS)

    Xiao Zhen; Yang Guojun; Li Yue; Shi Zhengang; Yu Suyuan

    2014-01-01

    In this paper, a model for analyzing internal contact stress arid external load of ball bearing from rotor displacement was developed based on the Hertz contact theory and applied to the analysis of the rotor drop test in HTR-10 helium circulator equipped with AMB (Active Magnetic Bearing) to gain a better understanding of auxiliary bearing performance at different stages after the rotor drop. It was shown that the auxiliary bearing can well resist axial impact produced by rotor drop, avoiding of internal severe plastic deformation and damage to the performance of the auxiliary bearing. Rotor's rotary motion and the heat accumulation of the inner ring resulted from the initial acute acceleration are the main contributor of radial load during the rotor idling and may cause the failure of auxiliary bearing. This paper analyzed the influence of this load and confirmed that the auxiliary bearing can still work in its loading limits. (authors)

  3. Effect of oil around the pin boss bearing on bearing friction force; Piston pin jikuukebu kinbo no junkatsuyu ga masatsuryoku ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Takiguchi, M; Suhara, T; Ato, S; Someya, T [Musashi Institute of Technology, Tokyo (Japan)

    1997-10-01

    Piston pin bearings are engine parts placed under severe lubricating condition because of the high unit load and temperature and the low sliding speeds. Therefore, they are vulnerable to many lubrication problems such as abnormal wear, scuffs and seizures. In our recent study, the bearing friction were measured using a original measuring device and it was found out that the lubricating conditions of piston pin boss bearings are non-fluid lubrication due to the oil starvation. In this study, we have also measured the lubricating oil behavior around the pin boss bearing using a special cylinder with glass window, and analyzed the relationship between the friction force and the oil behavior at the pin boss bearings in a actual operating gasoline engine. 2 refs., 9 figs., 1 tab.

  4. The Link between Poverty, the Proliferation of Violence and the Development of Traumatic Stress among Urban Youth in the United States to School Violence: A Trauma Informed, Social Justice Approach to School Violence

    Science.gov (United States)

    Rawles, Portia D.

    2010-01-01

    This paper presents two premises regarding school violence in urban America. First, that traumatic stress among urban youth in the United States is a key factor in the development and exacerbation of school violence in urban areas. Secondly, an efficacious approach to the resolution of school violence cannot be achieved without addressing this…

  5. Development of crack growth and crack initiation test units for stress corrosion cracking examinations in high-temperature water environments under neutron irradiation (1) (Contract research)

    International Nuclear Information System (INIS)

    Izumo, Hironobu; Ishida, Takuya; Kawamata, Kazuo; Inoue, Shuichi; Ide, Hiroshi; Saito, Takashi; Ishitsuka, Etsuo; Chimi, Yasuhiro; Ise, Hideo; Miwa, Yukio; Ugachi, Hirokazu; Nakano, Junichi; Kaji, Yoshiyuki; Tsukada, Takashi

    2009-04-01

    To evaluate integrity of irradiation-assisted stress corrosion cracking (IASCC) on in-core structural materials used in light water reactors (LWRs), useful knowledge regarding IASCC has been obtained mainly by post-irradiation examinations (PIEs). In the core of commercial LWRs, however, the actual IASCC occurs under the effects of irradiation on both materials and high-temperature water environment. Therefore, it is necessary to confirm the suitability of the knowledge by PIE with comparison to IASCC behaviors during in-core SCC tests. Fundamental techniques for in-core crack growth and crack initiation tests have been developed already at the Japan Materials Testing Reactor (JMTR) of the Japan Atomic Energy Agency (JAEA). For the in-core crack growth test technique, to evaluate the effects of neutron irradiation on stainless steels irradiated to low neutron fluences, it is indispensable to develop new loading technique which is applicable to compact tension (CT) specimens with thickness of 0.5 inch (0.5T), from the viewpoint of validity based on the fracture mechanics. Based on the present technical investigation for the in-core loading technique, it is expected that a target load of 7.6 kN approximately can apply to a 0.5T-CT specimen by adopting a loading unit of a lever type instead of the previous uni-axial tension type. For the in-core crack initiation test technique, moreover, construction of a loading unit adopting linear variable differential transformers (LVDTs) has been investigated and technical issues have examined. (author)

  6. The correct "ball bearings" data.

    Science.gov (United States)

    Caroni, C

    2002-12-01

    The famous data on fatigue failure times of ball bearings have been quoted incorrectly from Lieblein and Zelen's original paper. The correct data include censored values, as well as non-fatigue failures that must be handled appropriately. They could be described by a mixture of Weibull distributions, corresponding to different modes of failure.

  7. Little Bear Fire Summary Report

    Science.gov (United States)

    Sarah McCaffrey; Melanie Stidham; Hannah. Brenkert-Smith

    2013-01-01

    In June 2012, immediately after the Little Bear Fire burned outside Ruidoso, New Mexico, a team of researchers interviewed fire managers, local personnel, and residents to understand perceptions of the event itself, communication, evacuation, and pre-fire preparedness. The intensity of fire behavior and resulting loss of 242 homes made this a complex fire with a...

  8. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  9. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

    OpenAIRE

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-01-01

    © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we...

  10. Seismic isolation of nuclear power plants using elastomeric bearings

    Science.gov (United States)

    Kumar, Manish

    Seismic isolation using low damping rubber (LDR) and lead-rubber (LR) bearings is a viable strategy for mitigating the effects of extreme earthquake shaking on safety-related nuclear structures. Although seismic isolation has been deployed in nuclear structures in France and South Africa, it has not seen widespread use because of limited new build nuclear construction in the past 30 years and a lack of guidelines, codes and standards for the analysis, design and construction of isolation systems specific to nuclear structures. The nuclear accident at Fukushima Daiichi in March 2011 has led the nuclear community to consider seismic isolation for new large light water and small modular reactors to withstand the effects of extreme earthquakes. The mechanical properties of LDR and LR bearings are not expected to change substantially in design basis shaking. However, under shaking more intense than design basis, the properties of the lead cores in lead-rubber bearings may degrade due to heating associated with energy dissipation, some bearings in an isolation system may experience net tension, and the compression and tension stiffness may be affected by the horizontal displacement of the isolation system. The effects of intra-earthquake changes in mechanical properties on the response of base-isolated nuclear power plants (NPPs) were investigated using an advanced numerical model of a lead-rubber bearing that has been verified and validated, and implemented in OpenSees and ABAQUS. A series of experiments were conducted at University at Buffalo to characterize the behavior of elastomeric bearings in tension. The test data was used to validate a phenomenological model of an elastomeric bearing in tension. The value of three times the shear modulus of rubber in elastomeric bearing was found to be a reasonable estimate of the cavitation stress of a bearing. The sequence of loading did not change the behavior of an elastomeric bearing under cyclic tension, and there was no

  11. Batch fabrication of carbon nanotube bearings

    International Nuclear Information System (INIS)

    Subramanian, A; Dong, L X; Tharian, J; Sennhauser, U; Nelson, B J

    2007-01-01

    Relative displacements between the atomically smooth, nested shells in multiwalled carbon nanotubes (MWNTs) can be used as a robust nanoscale motion enabling mechanism. Here, we report on a novel method suited for structuring large arrays of MWNTs into such nanobearings in a parallel fashion. By creating MWNT nanostructures with nearly identical electrical circuit resistance and heat transport conditions, uniform Joule heating across the array is used to simultaneously engineer the shell geometry via electric breakdown. The biasing approach used optimizes process metrics such as yield and cycle-time. We also present the parallel and piecewise shell engineering at different segments of a single nanotube to construct multiple, but independent, high density bearings. We anticipate this method for constructing electromechanical building blocks to be a fundamental unit process for manufacturing future nanoelectromechanical systems (NEMS) with sophisticated architectures and to drive several nanoscale transduction applications such as GHz-oscillators, shuttles, memories, syringes and actuators

  12. TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING

    Science.gov (United States)

    Longhurst, G.E.

    1961-07-11

    A two-direction motion bearing which is incorporated in a refueling nuclear fuel element trsnsfer tool assembly is described. A plurality of bi- directional bearing assembliesare fixed equi-distantly about the circumference of the transfer tool assembly to provide the tool assembly with a bearing surface- for both axial and rotational motion. Each bi-directional bearing assembly contains a plurality of circumferentially bulged rollers mounted in a unique arrangement which will provide a bearing surface for rotational movement of the tool assembly within a bore. The bi-direc tional bearing assembly itself is capable of rational motion and thus provides for longitudinal movement of the tool assembly.

  13. Estimating Wear Of Installed Ball Bearings

    Science.gov (United States)

    Keba, John E.; Mcvey, Scott E.

    1993-01-01

    Simple inspection and measurement technique makes possible to estimate wear of balls in ball bearing, without removing bearing from shaft on which installed. To perform measurement, one observes bearing cage while turning shaft by hand to obtain integral number of cage rotations and to measure, to nearest 2 degrees, number of shaft rotations producing cage rotations. Ratio between numbers of cages and shaft rotations depends only on internal geometry of bearing and applied load. Changes in turns ratio reflect changes in internal geometry of bearing provided measurements made with similar bearing loads. By assuming all wear occurs on balls, one computes effective value for this wear from change in turns ratio.

  14. EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

    Directory of Open Access Journals (Sweden)

    Jarosław KACZOR

    2014-06-01

    Full Text Available Durability deep groove ball bearings depends on factors (called attributes design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bearings to work three-bearing shafts, including elasticity and resilience three-bearing shafts.

  15. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  16. Study of hydrodynamic behaviour of large bearings depending on the viscosity of the lubricant

    Directory of Open Access Journals (Sweden)

    Barabas Sorin

    2017-01-01

    Full Text Available The research refers to study of hydrodynamic behavior of large bearings equipped with automatic lubrication system, where the liquid used may have a viscosity with variable values depending on the temperature or depending on the additive used. The introduction of additives with nanoparticles causes modification of viscosity and a significant reduction of friction coefficient. This study establishes a direct link between the friction, viscosity and tensions that occur in the contact area. Experimental studies confirm improving tribological properties of the contact area between the bearing rollers and raceways, through attracting nanoparticles on surfaces in contact and reducing friction coefficient. Accomplished finite element analysis showed decrease of the contact stresses, therefore decrease of the wear and increase the life of the bearing. Research has concluded that influencing viscosity and friction coefficient of lubricant can result in reducing wear of the bearing components, as well as increase the lifetime of bearing.

  17. Seismic evaluation of a large nuclear pump bearing using non-linear dynamic analysis

    International Nuclear Information System (INIS)

    Huber, K.A.; Hugins, M.S.

    1983-01-01

    Hydrostatic bearings of a large vertical pump using sodium as the lubricant were critically examined to determine their ability to withstand seismic loads. Initial linear dynamics analyses predicted journal displacements to exceed bearing clearance by a ratio of 3:1. Equivalent time-history excitations were then developed from the response spectra to determine the number, magnitude, and duration of the bearing impact loads. Predicted loads were further reduced by 50% by modeling non-linear bearing characteristics normally present but not generally included in conventional linear analyses. Results are presented of the comprehensive design evaluation performed, based on these non-linear predictions, that assess stress, wear, and fatigue to demonstrate hydrostatic bearing integrity

  18. Cortisol levels in hair of East Greenland polar bears.

    Science.gov (United States)

    Bechshøft, T Ø; Sonne, C; Dietz, R; Born, E W; Novak, M A; Henchey, E; Meyer, J S

    2011-01-15

    To demonstrate the ability to assess long-term hypothalamic-pituitary-adrenocortical (HPA) axis activity in polar bears (Ursus maritimus), a pilot study was conducted in which cortisol concentrations was analyzed in hair from 7 female (3-19 years) and 10 male (6-19 years) East Greenland polar bears sampled in 1994-2006. The hair was chosen as matrix as it is non-invasive, seasonally harmonized, and has been validated as an index of long-term changes in cortisol levels. The samples were categorized according to contamination: eight were clean (2 females, 6 males), 5 had been contaminated with bear blood (2 F, 3 M), and 4 with bear fat (3 F, 1 M). There was no significant difference in cortisol concentration between the three categories after external contamination was removed. However, contaminated hair samples should be cleaned before cortisol determination. Average hair cortisol concentration was 8.90 pg/mg (range: 5.5 to 16.4 pg/mg). There was no significant correlation between cortisol concentration and age (p=0.81) or sampling year (p=0.11). However, females had higher mean cortisol concentration than males (females mean: 11.0 pg/mg, males: 7.3 pg/mg; p=0.01). The study showed that polar bear hair contains measurable amounts of cortisol and that cortisol in hair may be used in studies of long-term stress in polar bears. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. A proposed lexicon of terms and concepts for human-bear management in North America

    Science.gov (United States)

    Hopkins, John B.; Herrero, Stephen; Shideler, Richard T.; Gunther, Kerry A.; Schwartz, Charles C.; Kalinowski, Steven T.

    2010-01-01

    We believe that communication within and among agency personnel in the United States and Canada about the successes and failures of their human–bear (Ursidae) management programs will increase the effectiveness of these programs and of bear research. To communicate more effectively, we suggest agencies clearly define terms and concepts used in human–bear management and use them in a consistent manner. We constructed a human–bear management lexicon of terms and concepts using a modified Delphi method to provide a resource that facilitates more effective communication among human–bear management agencies. Specifically, we defined 40 terms and concepts in human–bear management and suggest definitions based on discussions with 13 other professionals from the United States and Canada. Although new terms and concepts will emerge in the future and definitions will evolve as we learn more about bear behavior and ecology, our purpose is to suggest working definitions for terms and concepts to help guide human–bear management and research activities in North America. Applications or revisions of these definitions may be useful outside of North America.

  20. Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

    Science.gov (United States)

    Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

    2012-01-01

    We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

  1. Technology development for indigenous water lubricated bearings

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2010-01-01

    Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

  2. Research In Diagnosing Bearing Defects From Vibrations

    Science.gov (United States)

    Zoladz, T.; Earhart, E.; Fiorucci, T.

    1995-01-01

    Report describes research in bearing-defect signature analysis - use of vibration-signal analysis to diagnose defects in roller and ball bearings. Experiments performed on bearings in good condition and other bearings in which various parts scratched to provide known defects correlated with vibration signals. Experiments performed on highly instrumented motor-driven rotor assembly at speeds up to 10,050 r/min, using accelerometers, velocity probes, and proximity sensors mounted at various locations on assembly to measure vibrations.

  3. Dynamic characteristics of lead rubber bearings with dynamic two-dimensional test equipment

    International Nuclear Information System (INIS)

    Ohtori, Y.; Ishida, K.; Mazda, T.

    1994-01-01

    Although studies have previously been done on the static mechanical properties of lead rubber bearings, this study aims to grasp the dynamic characteristics of lead rubber bearings from experimental results, using two-dimensional dynamic test equipment which is designed to grasp in detail such dynamic characteristics as deformation capacity and proof stress. This paper describes the results from three types of tests: (1) dynamic mechanical properties tests, (2) cyclic loading tests, and (3) dynamic ultimate tests. Through these tests, it was confirmed that the dynamic characteristics of lead rubber bearings are independent of strain rate

  4. Establishing a definition of polar bear (Ursus maritimus) health: A guide to research and management activities

    Science.gov (United States)

    Patyk, Kelly A.; Duncan, Colleen G.; Nol, Pauline; Sonne, C.; Laidre, Kristin L.; Obbard, Martyn E.; Wiig, Øystein; Aars, Jon; Regehr, Eric V.; Gustafson, L.; Atwood, Todd C.

    2015-01-01

    The meaning of health for wildlife and perspectives on how to assess and measure health, are not well characterized. For wildlife at risk, such as some polar bear (Ursus maritimus) subpopulations, establishing comprehensive monitoring programs that include health status is an emerging need. Environmental changes, especially loss of sea ice habitat, have raised concern about polar bear health. Effective and consistent monitoring of polar bear health requires an unambiguous definition of health. We used the Delphi method of soliciting and interpreting expert knowledge to propose a working definition of polar bear health and to identify current concerns regarding health, challenges in measuring health, and important metrics for monitoring health. The expert opinion elicited through the exercise agreed that polar bear health is defined by characteristics and knowledge at the individual, population, and ecosystem level. The most important threats identified were in decreasing order: climate change, increased nutritional stress, chronic physiological stress, harvest management, increased exposure to contaminants, increased frequency of human interaction, diseases and parasites, and increased exposure to competitors. Fifteen metrics were identified to monitor polar bear health. Of these, indicators of body condition, disease and parasite exposure, contaminant exposure, and reproductive success were ranked as most important. We suggest that a cumulative effects approach to research and monitoring will improve the ability to assess the biological, ecological, and social determinants of polar bear health and provide measurable objectives for conservation goals and priorities and to evaluate progress.

  5. Establishing a definition of polar bear (Ursus maritimus) health: a guide to research and management activities.

    Science.gov (United States)

    Patyk, Kelly A; Duncan, Colleen; Nol, Pauline; Sonne, Christian; Laidre, Kristin; Obbard, Martyn; Wiig, Øystein; Aars, Jon; Regehr, Eric; Gustafson, Lori L; Atwood, Todd

    2015-05-01

    The meaning of health for wildlife and perspectives on how to assess and measure health, are not well characterized. For wildlife at risk, such as some polar bear (Ursus maritimus) subpopulations, establishing comprehensive monitoring programs that include health status is an emerging need. Environmental changes, especially loss of sea ice habitat, have raised concern about polar bear health. Effective and consistent monitoring of polar bear health requires an unambiguous definition of health. We used the Delphi method of soliciting and interpreting expert knowledge to propose a working definition of polar bear health and to identify current concerns regarding health, challenges in measuring health, and important metrics for monitoring health. The expert opinion elicited through the exercise agreed that polar bear health is defined by characteristics and knowledge at the individual, population, and ecosystem level. The most important threats identified were in decreasing order: climate change, increased nutritional stress, chronic physiological stress, harvest management, increased exposure to contaminants, increased frequency of human interaction, diseases and parasites, and increased exposure to competitors. Fifteen metrics were identified to monitor polar bear health. Of these, indicators of body condition, disease and parasite exposure, contaminant exposure, and reproductive success were ranked as most important. We suggest that a cumulative effects approach to research and monitoring will improve the ability to assess the biological, ecological, and social determinants of polar bear health and provide measurable objectives for conservation goals and priorities and to evaluate progress. Published by Elsevier B.V.

  6. Positive Reinforcement Training for Blood Collection in Grizzly Bears (Ursus arctos horribilis) Results in Undetectable Elevations in Serum Cortisol Levels: A Preliminary Investigation.

    Science.gov (United States)

    Joyce-Zuniga, Nicole M; Newberry, Ruth C; Robbins, Charles T; Ware, Jasmine V; Jansen, Heiko T; Nelson, O Lynne

    2016-01-01

    Training nonhuman animals in captivity for participation in routine husbandry procedures is believed to produce a lower stress environment compared with undergoing a general anesthetic event for the same procedure. This hypothesis rests largely on anecdotal evidence that the captive subjects appear more relaxed with the trained event. Blood markers of physiological stress responses were evaluated in 4 captive grizzly bears (Ursus arctos horribilis) who were clicker-trained for blood collection versus 4 bears who were chemically immobilized for blood collection. Serum cortisol and immunoglobulin A (IgA) and plasma β-endorphin were measured as indicators of responses to stress. Plasma β-endorphin was not different between the groups. Serum IgA was undetectable in all bears. Serum cortisol was undetectable in all trained bears, whereas chemically immobilized bears had marked cortisol elevations (p bears with extensive recent immobilization experience. These findings support the use of positive reinforcement training for routine health procedures to minimize anxiety.

  7. Cool Polar Bears: Dabbing on the Texture

    Science.gov (United States)

    O'Connell, Jean

    2011-01-01

    In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

  8. 49 CFR 229.64 - Plain bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plain bearings. 229.64 Section 229.64 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....64 Plain bearings. A plain bearing box shall contain visible free oil and may not be cracked to the...

  9. Bears and pipeline construction in Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Follmann, E.H.; Hechtel, J.L. (Univ. of Alaska Fairbanks, AK (USA))

    1990-06-01

    Serious problems were encountered with bears during construction of the 1274-km trans-Alaska oil pipeline between Prudhoe Bay and Valdez. This multi-billion-dollar project traversed both black bear (Ursus americanus Pallas) and grizzly bear (U. arctos L.) habitat throughtout its entire length. Plans for dealing with anticipated problems with bears were often inadequate. Most (71%) problems occurred north of the Yukon River in a previously roadless wilderness where inadequate refuse disposal and widespread animal feeding created dangerous situations. Of the 192 officially reported bear problems associated with the Trans-Alaska Pipeline System (TAPS) (1971-1979), about 65% involved the presence of bears in camps or dumps, 13% the feeding of bears on garbage or handouts, 10% property damage or economic loss, 7% bears under and in buildings, and only 5% charges by bears. Remarkably, no bear-related injuries were reported, suggesting that bears became accustomed to people and did not regard them as a threat. Following construction of the TAPS there have been proposals for pipelines to transport natural gas from Prudhoe Bay to southern and Pacific-rim markets. Based on past experience, some animal control measures were developed during the planning phase for the authorized gas pipeline route in Alaska. Fences installed around 100-person survey camps were found to be effective in deterring bears in two traditionally troublesome areas. 16 refs., 7 figs., 1 tab.

  10. Fractal analysis of polar bear hairs

    Directory of Open Access Journals (Sweden)

    Wang Qing-Li

    2015-01-01

    Full Text Available Hairs of a polar bear (Ursus maritimus are of superior properties such as the excellent thermal protection. Why do polar bears can resist such cold environment? The paper concludes that its fractal porosity plays an important role, and its fractal dimensions are very close to the golden mean, 1.618, revealing the possible optimal structure of polar bear hair.

  11. 36 CFR 13.1236 - Bear orientation.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bear orientation. 13.1236 Section 13.1236 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear...

  12. 14 CFR 29.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 29.623 Section 29.623... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.623 Bearing factors. (a... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  13. 14 CFR 27.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 27.623 Section 27.623... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  14. 14 CFR 25.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 25.623 Section 25.623... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  15. 14 CFR 23.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 23.623 Section 23.623... Bearing factors. (a) Each part that has clearance (free fit), and that is subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of normal relative motion. (b) For...

  16. The BEAR Beamline at Elettra

    International Nuclear Information System (INIS)

    Nannarone, S.; Pasquali, L.; Selvaggi, G.; Borgatti, F.; DeLuisa, A.; Doyle, B.P.; Gazzadi, G.C.; Giglia, A.; Finetti, P.; Pedio, M.; Mahne, N.; Naletto, G.; Pelizzo, M.G.; Tondello, G.

    2004-01-01

    The BEAR (Bending Magnet for Emission Absorption and Reflectivity) beamline is installed at the right exit of the 8.1 bending magnet at ELETTRA. The beamline - in operation since January 2003 - delivers linear and circularly polarized radiation in the 5 - 1600 eV energy range. The experimental station is composed of a UHV chamber for reflectivity, absorption, fluorescence and angle resolved photoemission measurements and a UHV chamber for in-situ sample preparation

  17. BEAR

    DEFF Research Database (Denmark)

    Houmøller, Sabina Storbjerg; Wolff, Anne; Hougaard, Dan Dupont

    2017-01-01

    profiling and fitting strategies. Data from 2000 patients are collected from the departments of Audiology in Odense and Aalborg University Hospital. Some of the registered variables include gender, age, and health related questions, noise exposure and whether they are suffering from tinnitus. The database...... subgroups of HA users, including experienced versus new HA users will be made. Previous noise exposure and the relation to the occurrence of tinnitus will be investigated as well....

  18. Scaling laws for radial foil bearings

    Science.gov (United States)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  19. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions.

    Science.gov (United States)

    Rode, Karyn D; Wilson, Ryan R; Regehr, Eric V; St Martin, Michelle; Douglas, David C; Olson, Jay

    2015-01-01

    Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986-1995 and 2008-2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions.

  20. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions.

    Directory of Open Access Journals (Sweden)

    Karyn D Rode

    Full Text Available Recent observations suggest that polar bears (Ursus maritimus are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986-1995 and 2008-2013 when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia, highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions.

  1. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    DEFF Research Database (Denmark)

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff...... bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas...... the liner has practically no influence on the flexure journal bearing's performance....

  2. Recent observations of intraspecific predation and cannibalism among polar bears in the southern Beaufort Sea

    Science.gov (United States)

    Amstrup, Steven C.; Stirling, I.; Smith, T.S.; Perham, C.; Thiemann, G.W.

    2006-01-01

    Intraspecific killing has been reported among polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus). Although cannibalism is one motivation for such killings, the ecological factors mediating such events are poorly understood. Between 24 January and 10 April 2004, we confirmed three instances of intraspecific predation and cannibalism in the Beaufort Sea. One of these, the first of this type ever reported for polar bears, was a parturient female killed at her maternal den. The predating bear was hunting in a known maternal denning area and apparently discovered the den by scent. A second predation event involved an adult female and cub recently emerged from their den, and the third involved a yearling male. During 24 years of research on polar bears in the southern Beaufort Sea region of northern Alaska and 34 years in northwestern Canada, we have not seen other incidents of polar bears stalking, killing, and eating other polar bears. We hypothesize that nutritional stresses related to the longer ice-free seasons that have occurred in the Beaufort Sea in recent years may have led to the cannibalism incidents we observed in 2004. ?? Springer-Verlag 2006.

  3. Mechanical analysis and optimisation of large and highly-loaded bearing rollers For the "Riesenrad" Ion Gantry

    CERN Document Server

    Reimoser, S A

    2000-01-01

    A carbon ion gantry would allow the irradiation of cancer patients with carbon ions from any direction in space best suited for therapy. Till today, such a machine has not been built due to the expected size, mass and cost. A novel design, called "Riesenrad" ion gantry, promises to provide a competitive solution. The central part of the Riesenrad, which can rotate ± 90°, is supported (statically determinate) on pendular bearing units with two rollers each. High precision requirements for the structure rule out any plastic deformations in the area of contact. The present report describes the design of the highly-loaded rollers. In order to achieve a large contact area and a uniform distribution of contact stresses, a "barrel shape" for the rollers is proposed. An analysis using the finite element method (FEM) was performed to optimise the roller design, namely to establish the required crown roll (camber radius).

  4. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic NiTi Ball Bearings

    Science.gov (United States)

    Dellacorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2017-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  5. A motor with superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Gladun, A.; Stoye, P.; Verges, P.; Gawalek, W.; Habisreuther, T.; Goernert, P.

    1993-01-01

    Superconducting bearings may be one of the most promising near term applications of HTSC. For use at liquid nitrogen temperature and below, they offer the advantage of lower energy consumption and higher reliability. Different bearing configurations have been proposed. But in order to substitute for conventional bearings a further increase in the critical current density of the superconductor and improved bearing concepts are necessary. For this it is necessary to take into account the peculiarities of the interaction between permanent magnets and bulk superconductors. As a contribution to this programme we present the model of a motor with superconducting magnetic bearings. (orig.)

  6. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  7. Valve assembly having remotely replaceable bearings

    International Nuclear Information System (INIS)

    Johnson, E.R.; Tanner, D.E.

    1980-01-01

    A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings

  8. Servo Reduces Friction In Flexure Bearing

    Science.gov (United States)

    Clingman, W. Dean

    1991-01-01

    Proposed servocontrol device reduces such resistive torques as stiction, friction, ripple, and cogging in flexure bearing described in LAR-14348, "Flexure Bearing Reduces Startup Friction". Reduces frictional "bump" torque encountered when bearing ball runs into buildup of grease on bearing race. Also used as cable follower to reduce torque caused by cable and hoses when they bend because of motion of bearing. New device includes torquer across ball race. Torquer controlled by servo striving to keep flexure at null, removing torque to outer ring. In effect, device is inner control loop reducing friction, but does not control platforms or any outer-control-loop functions.

  9. Tribology of a Combined Yaw Bearing and Brake for Wind Turbines

    DEFF Research Database (Denmark)

    Poulios, Konstantinos

    disc brake is typically included as an independent system. However, the increasing size of wind turbines makes roller element bearings an economically costly option. Moreover, the additional brake system increases complexity and consequently adds further production and maintenance costs. One...... of the innovations aiming at reducing complexity in the yaw system consists in combining a segmented sliding bearing and a brake into a single system. This thesis studies the tribological implications of such a hybrid sliding bearing and brake for the yaw system of wind turbines. Based to a large extent...... that are affected by the tendency for building larger units, is the yaw system of horizontal axis wind turbines. State of the art wind turbine yaw systems consist of either a large roller element bearing or a corresponding segmented sliding bearing that connects the wind turbine nacelle and tower. An additional...

  10. Technical specifications for the successful fabrication of laminated seismic isolation bearings

    Energy Technology Data Exchange (ETDEWEB)

    Kulak, R F [Argonne National Laboratory, Argonne, IL (United States)

    1992-07-01

    High damping steel-laminated elastomeric seismic isolation bearings are becoming a preferred device for isolating large buildings and structures. In the United States, the current reference design for the Advanced Liquid Metal Reactor uses laminated bearings for seismic isolation. These bearings are constructed from alternating layers of rubber and steel plates. They are typically designed for shear strains between 50 to 100 percent and expected to sustain two to three times these levels for beyond design basis loading considerations. The technical specifications used to procure these bearings are an important factor in assuring thatthe bearings meet the performance requirements of the design. The key aspects of the current version of the Technical Specifications are discussed in this paper. (author)

  11. Technical specifications for the successful fabrication of laminated seismic isolation bearings

    International Nuclear Information System (INIS)

    Kulak, R.F.

    1992-01-01

    High damping laminated elastomeric bearings are becoming one of the preferred devices for isolating large buildings and structures. IN the United States, the current reference design for the Advanced Liquid Metal Reactor uses laminated bearings for seismic isolation. These bearing are constructed from alternating layers of rubber and steel plates. They are typically designed for shear strains between 50 to 100 percent and expected to sustain two to three times these levels for beyond design basis loading considerations. The technical specifications used to procure these bearings are an important factor in assuring that the bearings that are installed under nuclear structures meet the performance requirements of the design. The key aspects of the current version of the Technical Specifications are discussed in this paper

  12. Technical specifications for the successful fabrication of laminated seismic isolation bearings

    International Nuclear Information System (INIS)

    Kulak, R.F.

    1992-01-01

    High damping steel-laminated elastomeric seismic isolation bearings are becoming a preferred device for isolating large buildings and structures. In the United States, the current reference design for the Advanced Liquid Metal Reactor uses laminated bearings for seismic isolation. These bearings are constructed from alternating layers of rubber and steel plates. They are typically designed for shear strains between 50 to 100 percent and expected to sustain two to three times these levels for beyond design basis loading considerations. The technical specifications used to procure these bearings are an important factor in assuring that the bearings meet the performance requirements of the design. The key aspects of the current version of the Technical Specifications are discussed in this paper. (author)

  13. Occurrence of post traumatic stress symptoms and their relationship to professional quality of life (ProQoL in nursing staff at a forensic psychiatric security unit: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Nonstad Kåre

    2009-04-01

    Full Text Available Abstract Background Violence is frequent towards nurses in forensic mental health hospitals. Implications of this high risk environment have not been systematically explored. This paper explores occurrence of symptoms on post traumatic stress and their relationship to professional quality of life. Methods Self report questionnaires assessing symptoms of post traumatic stress and professional quality of life were distributed among psychiatric nurses in a high security forensic psychiatric unit with high frequency of violent behaviour. Relationships between post traumatic stress symptoms, forensic nursing experience, type of ward and compassion satisfaction, burnout and compassion fatigue were explored. Results The prevalence of post traumatic stress symptoms was low. Low scores were found on compassion satisfaction. Length of psychiatric nursing experience and low scores on compassion satisfaction were correlated to increased post traumatic stress symptoms. Conclusion Although high violence frequency, low rate of post traumatic stress symptoms and low compassion satisfaction scores was found. High staff/patient ratio and emotional distance between staff and patients are discussed as protective factors.

  14. Occurrence of post traumatic stress symptoms and their relationship to professional quality of life (ProQoL) in nursing staff at a forensic psychiatric security unit: a cross-sectional study

    Science.gov (United States)

    Lauvrud, Christian; Nonstad, Kåre; Palmstierna, Tom

    2009-01-01

    Background Violence is frequent towards nurses in forensic mental health hospitals. Implications of this high risk environment have not been systematically explored. This paper explores occurrence of symptoms on post traumatic stress and their relationship to professional quality of life. Methods Self report questionnaires assessing symptoms of post traumatic stress and professional quality of life were distributed among psychiatric nurses in a high security forensic psychiatric unit with high frequency of violent behaviour. Relationships between post traumatic stress symptoms, forensic nursing experience, type of ward and compassion satisfaction, burnout and compassion fatigue were explored. Results The prevalence of post traumatic stress symptoms was low. Low scores were found on compassion satisfaction. Length of psychiatric nursing experience and low scores on compassion satisfaction were correlated to increased post traumatic stress symptoms. Conclusion Although high violence frequency, low rate of post traumatic stress symptoms and low compassion satisfaction scores was found. High staff/patient ratio and emotional distance between staff and patients are discussed as protective factors. PMID:19371413

  15. Identification of Bearing Failure Using Signal Vibrations

    Science.gov (United States)

    Yani, Irsyadi; Resti, Yulia; Burlian, Firmansyah

    2018-04-01

    Vibration analysis can be used to identify damage to mechanical systems such as journal bearings. Identification of failure can be done by observing the resulting vibration spectrum by measuring the vibration signal occurring in a mechanical system Bearing is one of the engine elements commonly used in mechanical systems. The main purpose of this research is to monitor the bearing condition and to identify bearing failure on a mechanical system by observing the resulting vibration. Data collection techniques based on recordings of sound caused by the vibration of the mechanical system were used in this study, then created a database system based bearing failure due to vibration signal recording sounds on a mechanical system The next step is to group the bearing damage by type based on the databases obtained. The results show the percentage of success in identifying bearing damage is 98 %.

  16. A prototype construction of bearing heater system

    International Nuclear Information System (INIS)

    Firman Silitonga

    2007-01-01

    A bearing heater system has been successfully constructed using transformer-like method of 1000 VA power, 220 V primary voltage, and 50 Hz electrical frequency. The bearing heater consists of primary coil 230 turns, U type and bar-type iron core with 36 cm 2 , 9 cm 2 ,and 3 cm 2 cross-section, and electrical isolation. The bearing heater is used to enlarge the diameter of the bearing so that it can be easily fixed on an electric motor shaft during replacement because the heating is conducted by treated the bearing as a secondary coil of a transformer. This bearing heater can be used for bearing with 3 and 6 cm of inner diameter and 12 cm of maximum outside diameter. (author)

  17. Noise of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2002-01-01

    The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  18. Seismic bearing capacity of strip footings on rock masses using the Hoek–Brown failure criterion

    Directory of Open Access Journals (Sweden)

    Amin Keshavarz

    2016-04-01

    Full Text Available In this paper, the bearing capacity of strip footings on rock masses has been studied in the seismic case. The stress characteristics or slip line method was used for analysis. The problem was analyzed in the plane strain condition using the Hoek–Brown failure criterion. First, the equilibrium equations along the stress characteristics were obtained and the rock failure criterion was applied. Then, the equations were solved using the finite difference method. A computer code has been provided for analysis. Given the footing and rock parameters, the code can calculate the stress characteristics network and obtain the stress distribution under the footing. The seismic effects have been applied as the horizontal and vertical pseudo-static coefficients. The results of this paper are very close to those of the other studies. The seismic bearing capacity of weightless rock masses can be obtained using the proposed equations and graphs without calculating the whole stress characteristics network.

  19. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.

    Science.gov (United States)

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-03-01

    Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  20. The R and D D`s bearing test benches; Les bancs d`essais de paliers de la DER

    Energy Technology Data Exchange (ETDEWEB)

    Vialettes, J.M. [Service Ensembles de Production, Departement Machines, Direction des Etudes et Recherches, Electricite de France (EDF), 92 - Clamart (France)

    1997-01-01

    In power generation plants, rotating machines are involved in energy transformation processes and safety systems. The bearings supporting the rotors and the thrust bearings play a crucial role in the reliability of these machines. The phenomena encountered straddle several disciplines: hydrodynamics, tribology, thermomechanics, materials and vibrations in a specific environment, namely: thin fluid film, solid mechanical components and shaft rotation. Means of analysing the behaviour of these components (bearings and thrust bearings) have been developed and implemented. These consists of the EDYOS (Etude Dynamique des Organes de Supportage) code for dynamically studying bearing devices and several related bench tests. In reality, in order to understand the complex physical phenomena encountered in these components, it is vital to carry out analyses and experimental validations. Since these investigations cannot be carried out on actual machines, test benches have been built which can subject the sample bearings to the equivalent stresses. (author) 14 figs.

  1. New conceptual copper alloy bearing for diesel engine to achieve longer life under higher load; Diesel engine yo komen`atsu chojumyo jikuuke no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tomikawa, T; Oshiro, H; Hashizume, K; Kamiya, S [Taiho Kogyo Co. Ltd., Aichi (Japan)

    1997-10-01

    Recently, the requirement like higher output, lower fuel consumption and cleaner exhaust gas for automotive engines has been increased. As a result, especially, higher bearing performance is required for diesel engine under a higher unit load and longer period. For this reason, we have developed the new conceptual copper alloy bearing to achieve higher performance under a higher unit load. This paper describes about the performance of this new bearing material. 3 refs., 12 figs., 5 tabs.

  2. Fixed and mobile-bearing total ankle prostheses: Effect on tibial bone strain.

    Science.gov (United States)

    Terrier, Alexandre; Fernandes, Caroline Sieger; Guillemin, Maïka; Crevoisier, Xavier

    2017-10-01

    Total ankle replacement is associated to a high revision rate. To improve implant survival, the potential advantage of prostheses with fixed bearing compared to mobile bearing is unclear. The objective of this study was to test the hypothesis that fixed and mobile bearing prostheses are associated with different biomechanical quantities typically associated to implant failure. With a validated finite element model, we compared three cases: a prosthesis with a fixed bearing, a prosthesis with a mobile bearing in a centered position, and a prosthesis with mobile bearing in an eccentric position. Both prostheses were obtained from the same manufacturer. They were tested on seven tibias with maximum axial compression force during walking. We tested the hypothesis that there was a difference of bone strain, bone-implant interfacial stress, and bone support between the three cases. We also evaluated, for the three cases, the correlations between bone support, bone strain and bone-implant interfacial stress. There were no statistically significant differences between the three cases. Overall, bone support was mainly trabecular, and less effective in the posterior side. Bone strain and bone-implant interfacial stress were strongly correlated to bone support. Even if slight differences are observed between fixed and mobile bearing, it is not enough to put forward the superiority of one of these implants regarding their reaction to axial compression. When associated to the published clinical results, our study provides no argument to warn surgeons against the use of two-components fixed bearing implants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Analysis of acoustic emission data for bearings subject to unbalance

    Directory of Open Access Journals (Sweden)

    Rapinder Sawhney

    2013-01-01

    Full Text Available Acoustic Emission (AE is an effective nondestructive method for investigating the behavior of materials under stress. In recent decades, AE applications in structural health monitoring have been extended to other areas such as rotating machineries and cutting tools. This research investigates the application of acoustic emission data for unbalance analysis and detection in rotary systems. The AE parameter of interest in this study is a discrete variable that covers the significance of count, duration and amplitude of AE signals. A statistical model based on Zero-Inflated Poisson (ZIP regression is proposed to handle over-dispersion and excess zeros of the counting data. The ZIP model indicates that faulty bearings can generate more transient wave in the AE waveform. Control charts can easily detect the faulty bearing using the parameters of the ZIP model. Categorical data analysis based on generalized linear models (GLM is also presented. The results demonstrate the significance of the couple unbalance.

  4. A retrospective study of end-stage renal disease in captive polar bears (Ursus maritimus).

    Science.gov (United States)

    LaDouceur, Elise E B; Davis, Barbara; Tseng, Flo

    2014-03-01

    This retrospective study summarizes 11 cases of end-stage renal disease (ESRD) in captive polar bears (Ursus maritimus) from eight zoologic institutions across the United States and Canada. Ten bears were female, one was male, and the mean age at the time of death was 24 yr old. The most common clinical signs were lethargy, inappetence, and polyuria-polydipsia. Biochemical findings included azotemia, anemia, hyperphosphatemia, and isosthenuria. Histologic examination commonly showed glomerulonephropathies and interstitial fibrosis. Based on submissions to a private diagnostic institution over a 16-yr period, ESRD was the most commonly diagnosed cause of death or euthanasia in captive polar bears in the United States, with an estimated prevalence of over 20%. Further research is needed to discern the etiology of this apparently common disease of captive polar bears.

  5. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    1991-01-01

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  6. Intersection of stress and gender in association with transitions in past year DSM-5 substance use disorder diagnoses in the United States.

    Science.gov (United States)

    Verplaetse, Terril L; Moore, Kelly E; Pittman, Brian P; Roberts, Walter; Oberleitner, Lindsay M; Smith, Philip H; Cosgrove, Kelly P; McKee, Sherry A

    2018-01-01

    Stress contributes to the development and maintenance of substance use disorders (SUD), with some research suggesting that the impact of stress on SUD is greater in women. However, this has yet to be evaluated in a national dataset, across major substances of abuse. Using data from the newly available U.S. National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; Wave 3; n =36,309) we evaluated relationships among past year stressful life events (0 or 1 vs. 2+ events, range 0-16) and gender, and their association with transitions (new vs. absent cases; ongoing vs. remitted cases) in Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) alcohol use disorder (AUD), tobacco use disorder (TUD), cannabis use disorder (CUD), and nonmedical prescription opioid use disorder (OUD) diagnoses. Having 2 or more stressful life events in the past year increased the odds of having a new AUD, TUD, CUD, and OUD (OR=3.14, 2.15, 5.52, and 3.06, respectively) or ongoing AUD, TUD, and CUD (OR=2.39, 2.62, and 2.95, respectively) compared to 0 or 1 stressful life event. A stress by gender interaction for new vs. absent AUD demonstrated that having 2 or more stressful life events was associated with increased odds of new AUD in men (OR=2.51) and even greater odds of new AUD in women (OR=3.94). Results highlight that stress is a robust factor in both men and women with new or ongoing substance use disorders, and that effective treatments for substance use should consider the role of stress in addiction etiology and maintenance. There was little evidence for gender differences in the role of stress on transitions in substance use disorders, except for the onset of alcohol use disorders. Given that rates of alcohol use disorders are increasing in women; the impact of stress needs to be considered.

  7. Development of a hybrid bearing using permanent magnets and piezoelectric actuators

    International Nuclear Information System (INIS)

    Park, Jung-Ho; Ham, Young-Bog; Yun, So-Nam; Lee, Hu-Seung

    2010-01-01

    In this study, a hybrid magnetic bearing with permanent magnets and piezoelectric actuators is investigated. First, in this study, a novel concept in which piezoelectric actuators are used to compensate for low stiffness and damping resulting from the unstable characteristics of a passive magnetic bearing using only permanent magnets is proposed. Secondly, the permanent magnets are optimally arranged through an electromagnetic field analysis. Then, the driving amplifier unit and a prototype radial bearing using the proposed concept are fabricated. Finally, basic characteristics, such as the results of an impact test and a rotational runout test with constant speed are investigated and discussed, and experiments using PID control method are conducted.

  8. Analysis of a spacecraft instrument ball bearing assembly lubricated by a perfluoroalkylether

    Science.gov (United States)

    Morales, W.; Jones, W. R., Jr.; Buckley, D. H.

    1986-01-01

    An analysis of a spacecraft instrument ball bearing assembly, subjected to a scanning life test, was performed to determine the possible case of rotational problems involving these units aboard several satellites. The analysis indicated an ineffective transfer of a fluorinated liquid lubricant from a phenolic retainer to the bearing balls. Part of the analysis led to a novel HPLC separation method employing a fluorinated mobile phase in conjunction with silica based size exclusion columns.

  9. METHODS OF ESTIMATION OF COMPLEX FREQUENCY DESCRIPTIONS OF LTM AND BRM BEARING KNOTS

    OpenAIRE

    A. Pohrebnyak

    2015-01-01

    The method of studying bearing units (ball bearings) of handling and construction of road machines in the low-frequency range of vibration-acoustic signal is presented. It includes: the choice of the method and place of vibration sensors installation, vibration signals registration modes, instruments, algorithms of processing and formation of diagnostic features of the signal, determination of the threshold values of the diagnostic parameter. The characteristic spectra of vibration velocities...

  10. Detection of Naturally Occurring Gear and Bearing Faults in a Helicopter Drivetrain

    Science.gov (United States)

    2014-01-01

    Detection of Naturally Occurring Gear and Bearing Faults in a Helicopter Drivetrain by Kelsen E. LaBerge, Eric C. Ames, and Brian D. Dykas...5066 ARL-TR-6795 January 2014 Detection of Naturally Occurring Gear and Bearing Faults in a Helicopter Drivetrain Kelsen E. LaBerge...ELEMENT NUMBER 6. AUTHOR(S) Kelsen E. LaBerge, Eric C. Ames, and Brian D. Dykas 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER

  11. Social Support and Parental Stress among Parents of Young Children with Autism Spectrum Disorder: An International Comparison of United States and China

    Science.gov (United States)

    Wang, Wen-Chi

    2016-01-01

    Parents of young children with autism spectrum disorder (ASD) are more likely to experience high parental stress compared to other parents, and social support has been identified in previous research as an effective buffer against stress. However, limited research has evaluated the associations between different types of social support and stress…

  12. Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

    Science.gov (United States)

    Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

    2016-01-01

    Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. A Novel Integral 5-DOFs Hybrid Magnetic Bearing with One Permanent Magnet Ring Used for Turboexpander

    Directory of Open Access Journals (Sweden)

    Bangcheng Han

    2014-01-01

    Full Text Available We propose a novel combined five-degrees-of-freedom (5-DOFs hybrid magnetic bearing (HMB with only one permanent magnet ring (PMR used for turboexpanders. It has two radial magnetic bearing (RMB units; each has four poles and one thrust magnetic bearing (TMB to control 5-DOFs. Based on one PMR, the bias flux of the two radial magnetic bearing units and the one thrust magnetic bearing unit is constructed. As a result, ultra-high-speed, lower power loss, small size, and low cost can be achieved. Furthermore, the equivalent magnetic circuit method and 3D finite element method (FEM are used to model and analyze the combined 5-DOFs HMB. The force-current, force-position, torque-coil currents, the torque-angle position, and the stiffness models of the combined 5-DOFs HMB are given. Moreover, its coupling problems between the RMB units and the AMB unit are also proposed in this paper. An example is given to clarify the mathematical models and the coupling problems, and the linearized models are proposed for the follow-up controller design.

  14. Remedial investigation work plan for Bear Creek Valley Operable Unit 1 (S-3 Ponds, Boneyard/Burnyard, Oil Landfarm, Sanitary Landfill 1, and the Burial Grounds, including Oil Retention Ponds 1 and 2) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1993-09-01

    The intent and scope of the work plan are to assemble all data necessary to facilitate selection of remediation alternatives for the sites in Bear Creek Valley Operable Unit 1 (BCV OU 1) such that the risk to human health and the environment is reduced to acceptable levels based on agreements with regulators. The ultimate goal is to develop a final Record Of Decision (ROD) for all of the OUs in BCV, including the integrator OU. However, the initial aim of the source OUs is to develop a ROD for interim measures. For source OUs such as BCV OU 1, data acquisition will not be carried out in a single event, but will be carried out in three stages that accommodate the schedule for developing a ROD for interim measures and the final site-wide ROD. The three stages are as follows: Stage 1, Assemble sufficient data to support decisions such as the need for removal actions, whether to continue with the remedial investigation (RI) process, or whether no further action is required. If the decision is made to continue the RI/FS process, then: Stage 2, Assemble sufficient data to allow for a ROD for interim measures that reduce risks to the human health and the environment. Stage 3, Provide input from the source OU that allows a final ROD to be issued for all OUs in the BCV hydrologic regime. One goal of the RI work plan will be to ensure that sampling operations required for the initial stage are not repeated at later stages. The overall goals of this RI are to define the nature and extent of contamination so that the impact of leachate, surface water runoff, and sediment from the OU I sites on the integrator OU can be evaluated, the risk to human health and the environment can be defined, and the general physical characteristics of the subsurface can be determined such that remedial alternatives can be screened

  15. Remedial investigation work plan for Bear Creek Valley Operable Unit 1 (S-3 Ponds, Boneyard/Burnyard, Oil Landfarm, Sanitary Landfill 1, and the Burial Grounds, including Oil Retention Ponds 1 and 2) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 1, Main text

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    The intent and scope of the work plan are to assemble all data necessary to facilitate selection of remediation alternatives for the sites in Bear Creek Valley Operable Unit 1 (BCV OU 1) such that the risk to human health and the environment is reduced to acceptable levels based on agreements with regulators. The ultimate goal is to develop a final Record Of Decision (ROD) for all of the OUs in BCV, including the integrator OU. However, the initial aim of the source OUs is to develop a ROD for interim measures. For source OUs such as BCV OU 1, data acquisition will not be carried out in a single event, but will be carried out in three stages that accommodate the schedule for developing a ROD for interim measures and the final site-wide ROD. The three stages are as follows: Stage 1, Assemble sufficient data to support decisions such as the need for removal actions, whether to continue with the remedial investigation (RI) process, or whether no further action is required. If the decision is made to continue the RI/FS process, then: Stage 2, Assemble sufficient data to allow for a ROD for interim measures that reduce risks to the human health and the environment. Stage 3, Provide input from the source OU that allows a final ROD to be issued for all OUs in the BCV hydrologic regime. One goal of the RI work plan will be to ensure that sampling operations required for the initial stage are not repeated at later stages. The overall goals of this RI are to define the nature and extent of contamination so that the impact of leachate, surface water runoff, and sediment from the OU I sites on the integrator OU can be evaluated, the risk to human health and the environment can be defined, and the general physical characteristics of the subsurface can be determined such that remedial alternatives can be screened.

  16. A review of bear farming and bear trade in Lao People's Democratic Republic

    Directory of Open Access Journals (Sweden)

    E. Livingstone

    2018-01-01

    Full Text Available This study reviews the bear farming industry in Lao PDR with the objective of documenting the current number of commercial bear facilities (i.e. captive bear facilities judged to be trading in bear bile and/or bears and bear parts and the number of bears contained within these facilities, noting changes since it was last examined between 2000 and 2012 by Livingstone and Shepherd (2014. We surveyed all known commercial bear facilities and searched for previously unrecorded facilities. We compared our records with Livingstone and Shepherd (2014 and corrected some duplicate records from their study. In 2017, we recorded seven commercial facilities; four dedicated bear farms, and three tiger farms that were reportedly also keeping bears. We found that between 2012 and 2017 the recorded number of dedicated bear farms reduced by two, and the recorded number of tiger farms also keeping bears increased by one. Within the same period, the total number of captive bears among all facilities in Lao PDR hardly changed (+one, but the number of bears within each facility did. The northern facilities, owned by ethnic Chinese, have expanded since 2012, and central and southern facilities have downsized or closed. While bear farming appears to be downsizing in Lao PDR overall, efforts to phase it out are undermined by the expansion of foreign owned facilities in the north, within Special and Specific Economic Zones that largely cater to a Chinese market, and where the Lao government's efforts to enforce laws and protect wildlife appear to be lacking. Closing the facilities in the north will require political will and decisive law enforcement. Keywords: Bear farms, Bear bile, Gall bladder, Urso-deoxycholic acid, Bear bile extraction facilities, Lao PDR, Ursus thibetanus

  17. Electron beam melting of bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

    1990-06-01

    This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

  18. Bearing Health Assessment Based on Chaotic Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Lu

    2013-01-01

    Full Text Available Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM. Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

  19. Trends in Controllable Oil Film Bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview about the theoretical and experimental achievements of mechatronics applied to oil film bearings, with the aim of: controlling the lateral vibration of flexible rotating shafts; modifying bearing dynamic characteristics, as stiffness and damping properties; increasing......" components and be applied to rotating machines with the goal of avoiding unexpected stops of plants, performing rotordynamic tests and identifying model parameters "on site". Emphasis is given to the controllable lubrication (active lubrication) applied to different types of oil film bearings, i...

  20. River-Based Experiential Learning: the Bear River Fellows Program

    Science.gov (United States)

    Rosenberg, D. E.; Shirley, B.; Roark, M. F.

    2012-12-01

    The Department of Civil and Environmental Engineering, Outdoor Recreation, and Parks and Recreation programs at Utah State University (USU) have partnered to offer a new, unique river-based experiential learning opportunity for undergraduates called the Bear River Fellows Program. The program allows incoming freshmen Fellows to experience a river first hand during a 5-day/4-night river trip on the nearby Bear River two weeks before the start of their first Fall semester. As part of the program, Fellows will navigate the Bear River in canoes, camp along the banks, interact with local water and environmental managers, collect channel cross section, stream flow, vegetation cover, and topological complexity data, meet other incoming freshmen, interact with faculty and graduate students, develop boating and leadership skills, problem solve, and participate as full members of the trip team. Subsequently, Fellows will get paid as undergraduate researchers during their Fall and Spring Freshman semesters to analyze, synthesize, and present the field data they collect. The program is a collaborative effort between two USU academic units and the (non-academic) division of Student Services and supports a larger National Science Foundation funded environmental modelling and management project for the lower Bear River, Utah watershed. We have advertised the program via Facebook and emails to incoming USU freshmen, received 35 applications (60% women), and accepted 5 Fellows into the program (3 female and 2 male). The river trip departs August 14, 2012. The poster will overview the Bear River Fellows Program and present qualitative and preliminary outcomes emerging from the trip and Fellows' work through the Fall semester with the field data they collect. We will also undertake more rigorous and longer longitudinal quantitative evaluation of Program outcomes (for example, in problem-solving and leadership) both in Spring 2013 and in subsequent 2013 and 2014 offerings of the

  1. Membrane Treatment of Liquid Salt Bearing Radioactive Wastes

    International Nuclear Information System (INIS)

    Dmitriev, S. A.; Adamovich, D. V.; Demkin, V. I.; Timofeev, E. M.

    2003-01-01

    The main fields of introduction and application of membrane methods for preliminary treatment and processing salt liquid radioactive waste (SLRW) can be nuclear power stations (NPP) and enterprises on atomic submarines (AS) utilization. Unlike the earlier developed technology for the liquid salt bearing radioactive waste decontamination and concentrating this report presents the new enhanced membrane technology for the liquid salt bearing radioactive waste processing based on the state-of-the-art membrane unit design, namely, the filtering units equipped with the metal-ceramic membranes of ''TruMem'' brand, as well as the electrodialysis and electroosmosis concentrators. Application of the above mentioned units in conjunction with the pulse pole changer will allow the marked increase of the radioactive waste concentrating factor and the significant reduction of the waste volume intended for conversion into monolith and disposal. Besides, the application of the electrodialysis units loaded with an ion exchange material at the end polishing stage of the radioactive waste decontamination process will allow the reagent-free radioactive waste treatment that meets the standards set for the release of the decontaminated liquid radioactive waste effluents into the natural reservoirs of fish-farming value

  2. [Contact characteristics research of acetabular weight-bearing area with different internal fixation methods after compression fracture of acetabular dome].

    Science.gov (United States)

    Xu, Bowen; Zhang, Qingsong; An, Siqi; Pei, Baorui; Wu, Xiaobo

    2017-08-01

    To establish the model of compression fracture of acetabular dome, and to measure the contact characteristics of acetabular weight-bearing area of acetabulum after 3 kinds of internal fixation. Sixteen fresh adult half pelvis specimens were randomly divided into 4 groups, 4 specimens each group. Group D was the complete acetabulum (control group), and the remaining 3 groups were prepared acetabular dome compression fracture model. The fractures were fixed with reconstruction plate in group A, antegrade raft screws in group B, and retrograde raft screws in group C. The pressure sensitive films were attached to the femoral head, and the axial compression test was carried out on the inverted single leg standing position. The weight-bearing area, average stress, and peak stress were measured in each group. Under the loading of 500 N, the acetabular weight-bearing area was significantly higher in group D than in other 3 groups ( P area were significantly higher in group B and group C than in group A, and the average stress and peak stress were significantly lower than in group A ( P 0.05). For the compression fracture of the acetabular dome, the contact characteristics of the weight-bearing area can not restore to the normal level, even if the anatomical reduction and rigid internal fixation were performed; compared with the reconstruction plate fixation, antegrade and retrograde raft screws fixations can increase the weight-bearing area, reduce the average stress and peak stress, and reduce the incidence of traumatic arthritis.

  3. Stress and Protists: No life without stress.

    Science.gov (United States)

    Slaveykova, Vera; Sonntag, Bettina; Gutiérrez, Juan Carlos

    2016-08-01

    We report a summary of the symposium "Stress and Protists: No life without stress", which was held in September 2015 on the VII European Congress of Protistology in partnership with the International Society of Protistologists (Seville, Spain). We present an overview on general comments and concepts on cellular stress which can be also applied to any protist. Generally, various environmental stressors may induce similar cell responses in very different protists. Two main topics are reported in this manuscript: (i) metallic nanoparticles as environmental pollutants and stressors for aquatic protists, and (ii) ultraviolet radiation - induced stress and photoprotective strategies in ciliates. Model protists such as Chlamydomonas reinhardtii and Tetrahymena thermophila were used to assess stress caused by nanoparticles while stress caused by ultraviolet radiation was tested with free living planktonic ciliates as well as with the symbiont-bearing model ciliate Paramecium bursaria. For future studies, we suggest more intensive analyses on protist stress responses to specific environmental abiotic and/or biotic stressors at molecular and genetic levels up to ecological consequences and food web dynamics. Copyright © 2016 Elsevier GmbH. All rights reserved.

  4. Seismic isolation of nuclear power plants using sliding isolation bearings

    Science.gov (United States)

    Kumar, Manish

    Nuclear power plants (NPP) are designed for earthquake shaking with very long return periods. Seismic isolation is a viable strategy to protect NPPs from extreme earthquake shaking because it filters a significant fraction of earthquake input energy. This study addresses the seismic isolation of NPPs using sliding bearings, with a focus on the single concave Friction Pendulum(TM) (FP) bearing. Friction at the sliding surface of an FP bearing changes continuously during an earthquake as a function of sliding velocity, axial pressure and temperature at the sliding surface. The temperature at the sliding surface, in turn, is a function of the histories of coefficient of friction, sliding velocity and axial pressure, and the travel path of the slider. A simple model to describe the complex interdependence of the coefficient of friction, axial pressure, sliding velocity and temperature at the sliding surface is proposed, and then verified and validated. Seismic hazard for a seismically isolated nuclear power plant is defined in the United States using a uniform hazard response spectrum (UHRS) at mean annual frequencies of exceedance (MAFE) of 10-4 and 10 -5. A key design parameter is the clearance to the hard stop (CHS), which is influenced substantially by the definition of the seismic hazard. Four alternate representations of seismic hazard are studied, which incorporate different variabilities and uncertainties. Response-history analyses performed on single FP-bearing isolation systems using ground motions consistent with the four representations at the two shaking levels indicate that the CHS is influenced primarily by whether the observed difference between the two horizontal components of ground motions in a given set is accounted for. The UHRS at the MAFE of 10-4 is increased by a design factor (≥ 1) for conventional (fixed base) nuclear structure to achieve a target annual frequency of unacceptable performance. Risk oriented calculations are performed for

  5. Gearbox Reliability Collaborative Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.

    2011-10-01

    NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.

  6. Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.

    Science.gov (United States)

    Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

    2012-04-20

    Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history.

  7. Treatment of alpha bearing wastes

    International Nuclear Information System (INIS)

    1988-01-01

    This report deals with the current state of the art of alpha waste treatment, which is an integral part of the overall nuclear waste management system. The International Atomic Energy Agency (IAEA) defines alpha bearing waste as 'waste containing one or more alpha emitting radionuclides, usually actinides, in quantities above acceptable limits'. The limits are established by national regulatory bodies. The limits above which wastes are considered as alpha contaminated refer to the concentrations of alpha emitters that need special consideration for occupational exposures and/or potential safety, health, or environmental impact during one or more steps from generation through disposal. Owing to the widespread use of waste segregation by source - that is, based upon the 'suspect origin' of the material - significant volumes of waste are being handled as alpha contaminated which, in fact, do not require such consideration by reason of risk or environmental concern. The quantification of de minimis concepts by national regulatory bodies could largely contribute to the safe reduction of waste volumes and associated costs. Other factors which could significantly contribute to the reduction of alpha waste arisings are an increased application of assaying and sorting, instrumentation and the use of feedback mechanisms to control or modify the processes which generate these wastes. Alpha bearing wastes are generated during fabrication and reprocessing of nuclear fuels, decommissioning of alpha contaminated facilities, and other activities. Most alpha wastes are contact handled, but a small portion may require shielding or remote handling because of high levels of neutron (n), beta (β), or gamma (γ) emissions associated with the waste material. This report describes the sources and characteristics of alpha wastes and strategies for alpha waste management. General descriptions of treatment processes for solid and liquid alpha wastes are included. 71 refs, 14 figs, 9 tabs

  8. Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

    Science.gov (United States)

    Jett, T.; Hall, P.; Thom, R.

    1991-01-01

    Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

  9. Relationships between spur- and orchard-level fruit bearing in almond (Prunus dulcis).

    Science.gov (United States)

    Tombesi, Sergio; Lampinen, Bruce D; Metcalf, Samuel; DeJong, Theodore M

    2011-12-01

    Almond is often considered to be a moderately alternate-bearing species but historical yield data typically do not exhibit clear patterns of alternate bearing at the orchard level, while research has indicated that spurs (the main fruit bearing unit in almond trees) rarely produce fruit in two subsequent years. The objective of the present work was to analyze the bearing behavior of almond trees at both the orchard level and the individual spur level over multiple years to explain this apparent paradox. The 10-year yield patterns of three almond cultivars grown at three different sites within California were analyzed for tendencies of alternate bearing at the orchard level. At the individual spur level, data on spur viability, and number of flowers and fruits per spur were collected on 2400 individually tagged spurs that were observed over 6 years to characterize bearing at that level. At the orchard level one cultivar (Nonpareil) did exhibit a tendency for alternate bearing at one site (Kern) but other cultivars and sites did not. The orchard and the individual trees in which the spur population study was conducted showed tendencies for alternate bearing but the spur population did not. Only a relatively small percentage of the total tagged spur population bore fruit in any given year and therefore while individual fruiting spurs exhibited a high level of non-bearing after fruiting the previous year the spurs that did produce fruit in any year generally did not constitute enough of the total spur population to exhibit alternate bearing at the whole population level. Our results suggest that annual bearing fluctuations in almond are probably mainly due to year-to-year variations of parameters affecting fruit set and that high rates of fruit set in a given year may involve a larger-than-normal percentage of a spur population in fruit bearing. This would limit the size of the spur population available for flowering in the subsequent year and could cause alternate

  10. Physical stream habitat dynamics in Lower Bear Creek, northern Arkansas

    Science.gov (United States)

    Reuter, Joanna M.; Jacobson, Robert B.; Elliott, Caroline M.

    2003-01-01

    We evaluated the roles of geomorphic and hydrologic dynamics in determining physical stream habitat in Bear Creek, a stream with a 239 km2 drainage basin in the Ozark Plateaus (Ozarks) in northern Arkansas. During a relatively wet 12-month monitoring period, the geomorphology of Bear Creek was altered by a series of floods, including at least four floods with peak discharges exceeding a 1-year recurrence interval and another flood with an estimated 2- to 4-year recurrence interval. These floods resulted in a net erosion of sediment from the study reach at Crane Bottom at rates far in excess of other sites previously studied in the Ozarks. The riffle-pool framework of the study reach at Crane Bottom was not substantially altered by these floods, but volumes of habitat in riffles and pools changed. The 2- to 4-year flood scoured gravel from pools and deposited it in riffles, increasing the diversity of available stream habitat. In contract, the smaller floods eroded gravel from the riffles and deposited it in pools, possibly flushing fine sediment from the substrate but also decreasing habitat diversity. Channel geometry measured at the beginning of the study was use to develop a two-dimensional, finite-element hydraulic model at assess how habitat varies with hydrologic dynamics. Distributions of depth and velocity simulated over the range of discharges observed during the study (0.1 to 556 cubic meters per second, cms) were classified into habitat units based on limiting depths and Froude number criteria. The results indicate that the areas of habitats are especially sensitive to change to low to medium flows. Races (areas of swift, relatively deep water downstream from riffles) disappear completely at the lowest flows, and riffles (areas of swift, relatively shallow water) contract substantially in area. Pools also contract in area during low flow, but deep scours associated with bedrock outcrops sustain some pool area even at the lowest modeled flows. Modeled

  11. Unbalance Response Prediction for Rotors on Ball Bearings Using Speed and Load Dependent Nonlinear Bearing Stiffness

    Science.gov (United States)

    Fleming, David P.; Poplawski, J. V.

    2003-01-01

    Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant bearing stiffness. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.

  12. Phylogeography of mitochondrial DNA variation in brown bears and polar bears

    Science.gov (United States)

    Shields, Gerald F.; Adams, Deborah; Garner, Gerald W.; Labelle, Martine; Pietsch, Jacy; Ramsay, Malcolm; Schwartz, Charles; Titus, Kimberly; Williamson, Scott

    2000-01-01

    We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

  13. Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

    Science.gov (United States)

    Shields, G F; Adams, D; Garner, G; Labelle, M; Pietsch, J; Ramsay, M; Schwartz, C; Titus, K; Williamson, S

    2000-05-01

    We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples. Copyright 2000 Academic Press.

  14. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics.

    Science.gov (United States)

    Tse, Peter W; Wang, Dong

    2017-02-14

    Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL). Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI) so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  15. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    Directory of Open Access Journals (Sweden)

    Peter W. Tse

    2017-02-01

    Full Text Available Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL. Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  16. Associations between sedation, delirium and post-traumatic stress disorder and their impact on quality of life and memories following discharge from an intensive care unit.

    Science.gov (United States)

    Svenningsen, Helle

    2013-04-01

    In the intensive care units (ICUs) sedation strategies have changed in the past decade towards less sedation and daily wake-up calls. Recent studies indicate that no sedation (after intubation) is most beneficial for patients. A smaller number of these patients have been assessed for post-traumatic stress disorder (PTSD) after ICU discharge, but none of them were assessed for delirium while in the ICU. In other studies, delirium in the ICU is described as distressing for the patients and increasing morbidity, i.e. dementia after discharge and mortality. The associations between sedation, delirium, and PTSD have not previous been described. The aim of this PhD study was to investigate: 1) how sedation is associated with delirium in the ICU, 2) the consequences of delirium in relation to PTSD, anxiety, and depression, 3) the consequences of delirium for the patients' memories from ICU and the health-related quality of life after discharge. In a prospective observation study with patients admitted a minimum of 48 hours to the ICUs in Aarhus or Hillerød, we included all patients aged > 17 years. Non-Danish-speaking, patients transferred from other ICUs and patients with brain injury that made delirium-assessment impossible were excluded. Patients were interviewed face-to-face after 1 week, and at 2 months and 6 months by telephone using six different questionnaires. Among 3,066 patients admitted to the ICUs, 942 fulfilled the inclusion criteria. Primarily due to the inability to test for delirium, 302 patients were later excluded. Of the remaining 640 patients, 65% were delirious on 1 or more days. Fluctuations in sedation levels increased the risk of delirium statistically significantly with or without adjustments for age, gender, severity of illness, surgical/medical patient, or ICU site. After 2 months vs. 6 months, 297 patients vs. 248 patients were interviewed. PTSD was found in 7% vs. 5%, anxiety in 6% vs. 4%, and depression in 10% at both interviews. Delirium

  17. Enhanced carbide precipitation during tempering of sub-zero Celsius treated AISI 52100 bearing steel

    DEFF Research Database (Denmark)

    Villa, Matteo; Pantleon, Karen; Somers, Marcel A. J.

    A 1.5%Cr, 1%C bearing steel was sub-zero Celsius treated after quenching.Transmission and reflection (synchrotron) X-Ray Diffraction were applied ex-situ at the HZBBESSY II synchrotron facility to quantify the phase fractions of martensite and austenite and determine the stress state in austenite...

  18. Friction coefficients of PTFE bearing liner

    Science.gov (United States)

    Daniels, C. M.

    1979-01-01

    Data discusses frictional characteristics of PTFE (polytetrafluoroethylene) under temperature extremes and in vacuum environment. Tests were also run on reduced scale hardware to determine effects of vacuum. Data is used as reference by designers of aircraft-control system rod-end bearings and for bearings used in polar regions.

  19. Shaft Center Orbit in Dynamically Loaded Bearings

    DEFF Research Database (Denmark)

    Klit, Peder

    2005-01-01

    The aim of this work is to demonstrate how to utilize the bearings damping coe±cients to estimate the orbit for a dynamically loaded journal bearing. The classical method for this analysis was developed by Booker in 1965 [1]and described further in 1972 [2]. Several authors have re¯ned this metho...

  20. Can polar bear hairs absorb environmental energy?

    Directory of Open Access Journals (Sweden)

    He Ji-Huan

    2011-01-01

    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.