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Sample records for boundary cohesive strength

  1. Determination of mode-I cohesive strength for interfaces

    DEFF Research Database (Denmark)

    Jørgensen, J. B.; Thouless, M. D.; Sørensen, Bent F.

    2016-01-01

    The cohesive strength is one of the governing parameters controlling crack deflection at interfaces, but measuring its magnitude is challenging. In this paper, we demonstrate a novel approach to determine the mode-I cohesive strength of an interface by using a 4-point single-edge-notch beam...... in response to this stress, before the main crack starts to grow. Observations using 2D digital-image correlation showed that an ''apparent" strain across the interface initially increases linearly with the applied load, but becomes nonlinear upon the initiation of the interface crack. The cohesive strength...

  2. Grain boundary embrittlement and cohesion enhancement in copper

    Energy Technology Data Exchange (ETDEWEB)

    Paxton, Anthony; Lozovoi, Alexander [Atomistic Simulation Centre, Queen' s University Belfast, BT7 1NN (United Kingdom); Schweinfest, Rainer [Science+Computing ag, Hagellocher Weg 71-5, 720270 T ubingen (Germany); Finnis, Michael [Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

    2008-07-01

    There has been a long standing debate surrounding the mechanism of grain boundary embrittlement and cohesion enhancement in metals. Embrittlement can lead to catastrophic failure such as happened in the Hinkley Point disaster, or indeed in the case of the Titanic. This kind of embrittlement is caused by segregation of low solubility impurities to grain boundaries. While the accepted wisdom is that this is a phenomenon driven by electronic or chemical factors, using language such as charge transfer and electronegativity difference; we believe that in copper, at least, both cohesion enhancement and reduction are caused by a simple size effect. We have developed a theory that allows us to separate unambiguously, if not uniquely, chemical and structural factors. We have studied a large number of solutes in copper using first principles atomistic simulation to support this argument, and the results of these calculations are presented here.

  3. COHESIVE STRENGTH OF DENTIN RESISTÊNCIA COESIVA DA DENTINA

    Directory of Open Access Journals (Sweden)

    Flávio Fernando DEMARCO

    1997-07-01

    Full Text Available The bond strength of dentin adhesives to dentin has increased after each generation. Although dentin substratum is part of the bonding process, little importance has been given to measure dentin cohesive strength. The aim of this study was to evaluate the cohesive strength of dentin in human canines. Seventeen non carious canines were selected. All of them had been extracted for more than one year. The teeth were ground until dentin square samples with approximately 2 X 2 mm were obtained. They were embedded in acrylic resin and subjected to shear stress, in a Wolpert Machine, at a crosshead speed of 0.5 mm/min. The mean cohesive strength of dentin in shear mode was 33.95 (+-9.72 MPa. The fracture surfaces were observed under a X40 magnification. A finite element analysis was performed to observe the stress distribution as related to the shear test. The failure pattern was compatible with the shear test and also with the stress distribution in the finite element analysisA resistência de união dos adesivos dentinários tem sido aumentada com o desenvolvimento de cada nova geração. Pouca importância tem sido dada à resistência coesiva da dentina. A proposta deste estudo foi avaliar a resistência coesiva da dentina. Dezessete caninos humanos hígidos, os quais tinham sido extraídos há mais de um ano, foram usados. Os dentes foram desgastados até a obtenção de corpos-de-prova em dentina, de formato quadrangular, com tamanho aproximado de 2 X 2 mm. Os dentes foram incluídos em resina acrílica e, então, submetidos ao teste de cisalhamento em uma máquina de ensaios universais Wolpert, com uma velocidade de 0,5 mm/min. A resistência coesiva média da dentina no teste de cisalhamento foi de 33,95 (+- 9,72 MPa. O tipo de fratura foi analisado com um aumento de 40X. Foi realizada uma análise com elemento finito, para observar a distribuição do estresse relacionada com o teste de cisalhamento. O padrão de fratura encontrado foi compat

  4. A boundary integral method for a dynamic, transient mode I crack problem with viscoelastic cohesive zone

    KAUST Repository

    Leise, Tanya L.; Walton, Jay R.; Gorb, Yuliya

    2009-01-01

    interpenetration, in contrast to the usual mode I boundary conditions that assume all unloaded crack faces are stress-free. The nonlinear viscoelastic cohesive zone behavior is motivated by dynamic fracture in brittle polymers in which crack propagation

  5. Rotational Failure of Rubble-pile Bodies: Influences of Shear and Cohesive Strengths

    Science.gov (United States)

    Zhang, Yun; Richardson, Derek C.; Barnouin, Olivier S.; Michel, Patrick; Schwartz, Stephen R.; Ballouz, Ronald-Louis

    2018-04-01

    The shear and cohesive strengths of a rubble-pile asteroid could influence the critical spin at which the body fails and its subsequent evolution. We present results using a soft-sphere discrete element method to explore the mechanical properties and dynamical behaviors of self-gravitating rubble piles experiencing increasing rotational centrifugal forces. A comprehensive contact model incorporating translational and rotational friction and van der Waals cohesive interactions is developed to simulate rubble-pile asteroids. It is observed that the critical spin depends strongly on both the frictional and cohesive forces between particles in contact; however, the failure behaviors only show dependence on the cohesive force. As cohesion increases, the deformation of the simulated body prior to disruption is diminished, the disruption process is more abrupt, and the component size of the fissioned material is increased. When the cohesive strength is high enough, the body can disaggregate into similar-size fragments, which could be a plausible mechanism to form asteroid pairs or active asteroids. The size distribution and velocity dispersion of the fragments in high-cohesion simulations show similarities to the disintegrating asteroid P/2013 R3, indicating that this asteroid may possess comparable cohesion in its structure and experience rotational fission in a similar manner. Additionally, we propose a method for estimating a rubble pile’s friction angle and bulk cohesion from spin-up numerical experiments, which provides the opportunity for making quantitative comparisons with continuum theory. The results show that the present technique has great potential for predicting the behaviors and estimating the material strengths of cohesive rubble-pile asteroids.

  6. Impurity effects on the grain boundary cohesion in copper

    Science.gov (United States)

    Li, Yunguo; Korzhavyi, Pavel A.; Sandström, Rolf; Lilja, Christina

    2017-12-01

    Segregated impurities at grain boundaries can dramatically change the mechanical behavior of metals, while the mechanism is still obscure in some cases. Here, we suggest a unified approach to investigate segregation and its effects on the mechanical properties of polycrystalline alloys using the example of 3 s p impurities (Mg, Al, Si, P, or S) at a special type Σ 5 (310 )[001 ] tilt grain boundary in Cu. We show that for these impurities segregating to the grain boundary, the strain contribution to the work of grain boundary decohesion is small and that the chemical contribution correlates with the electronegativity difference between Cu and the impurity. The strain contribution to the work of dislocation emission is calculated to be negative, while the chemical contribution is calculated to be always positive. Both the strain and chemical contributions to the work of dislocation emission generally become weaker with the increasing electronegativity from Mg to S. By combining these contributions together, we find, in agreement with experimental observations, that a strong segregation of S can reduce the work of grain boundary separation below the work of dislocation emission, thus embrittling Cu, while such an embrittlement cannot be produced by a P segregation because it lowers the energy barrier for dislocation emission relatively more than for work separation.

  7. A boundary integral method for a dynamic, transient mode I crack problem with viscoelastic cohesive zone

    KAUST Repository

    Leise, Tanya L.

    2009-08-19

    We consider the problem of the dynamic, transient propagation of a semi-infinite, mode I crack in an infinite elastic body with a nonlinear, viscoelastic cohesize zone. Our problem formulation includes boundary conditions that preclude crack face interpenetration, in contrast to the usual mode I boundary conditions that assume all unloaded crack faces are stress-free. The nonlinear viscoelastic cohesive zone behavior is motivated by dynamic fracture in brittle polymers in which crack propagation is preceeded by significant crazing in a thin region surrounding the crack tip. We present a combined analytical/numerical solution method that involves reducing the problem to a Dirichlet-to-Neumann map along the crack face plane, resulting in a differo-integral equation relating the displacement and stress along the crack faces and within the cohesive zone. © 2009 Springer Science+Business Media B.V.

  8. Effects of interface roughness on cohesive strength of self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chen [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Awasthi, Amnaya P. [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, 32611 (United States); Geubelle, Philippe H., E-mail: geubelle@illinois.edu [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Grady, Martha E.; Sottos, Nancy R. [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States)

    2017-03-01

    Highlights: • Self-assembled monolayer/transfer-printed gold interface modeled using continuum-level simulation. • Initial deformed film profile analyzed and instability assessed. • Effective cohesive response of SAM-enhanced interface extracted from spallation model. • Reduction of up to 70% cohesive strength of the interface from incorporation of roughness demonstrated. - Abstract: Self-assembled monolayers (SAMs) are aggregates of small molecular chains that have the property to form highly ordered assemblies. The choice of terminal groups on the chains makes them excellent contenders of molecular-level tailoring. Molecular dynamics (MD) simulations and experimental observations of spallation of two SAM-enhanced gold-film/silicon-substrate interfaces have shown that the cohesive strength of SAM-enriched transfer-printed interfaces is strongly dependent on the choice of terminal groups. Though the MD results of perfectly ordered atomistic surfaces show the same qualitative trend as the experiments, they over-predict the interfacial cohesive strengths by a factor of about 50. Results from AFM studies have revealed that the roughness of these interfaces is of the same order (∼1 nm) as the range of atomistic interactions. Hence, surface roughness is a key contributor in significantly reducing interfacial cohesive strength in these systems. In this manuscript, a continuum-level study is performed to investigate the influence of surface roughness on the cohesive strength of the interface between a Si/SAM substrate and a transfer-printed gold film. We approximate the film as a deformable continuum interacting with a rough substrate of SAMs represented by a harmonic function. Using a cohesive law derived from MD, spallation is simulated to evaluate the effective traction-separation characteristics for the rough SAM–gold interface. Our analysis shows that incorporating roughness may reduce the interfacial cohesive strength by an order of magnitude depending

  9. The influence of the grain boundary strength on the macroscopic properties of a polycrystalline aggregate

    International Nuclear Information System (INIS)

    Simonovski, Igor; Cizelj, Leon; Garrido, Oriol Costa

    2013-01-01

    Highlights: ► Grain boundary stiffness should be at least 1.5× higher that the stiffness of bulk grains. ► The ratio δ n pl /δ n el should be at least 400. ► Simultaneous increase of δ n el and δ n pl at constant grain boundary strength increases numerical stability but results in high percentage of damage grain boundary area. ► Shear contributes significantly to damage initialization. -- Abstract: In this work a model, based on a X-ray diffraction contrast tomography data of a stainless steel wire with a diameter of 0.4 mm is presented. As measured 3D grain geometry and crystallographic orientation of individual grains are directly transferred into a finite element model. Anisotropic elasticity and crystal plasticity constitutive laws are used for the bulk grain material while the grain boundaries are explicitly modeled using the cohesive zone approach. A parametric study on the effects of the grain boundary strength and other cohesive zone parameters on the macroscopic response and damaged grain boundary area of a polycrystalline aggregate is presented. Recommendations for the cohesive zone parameters values aimed at achieving low damaged grain boundary area during numerical tensile tests are given while at the same time taking into account the numerical stability of the simulations

  10. The influence of the grain boundary strength on the macroscopic properties of a polycrystalline aggregate

    Energy Technology Data Exchange (ETDEWEB)

    Simonovski, Igor, E-mail: Igor.Simonovski@ec.europa.eu [European Commission, DG-JRC, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Cizelj, Leon, E-mail: Leon.Cizelj@ijs.si [Jožef Stefan Institute, Reactor Engineering Division, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Garrido, Oriol Costa, E-mail: Oriol.Costa@ijs.si [Jožef Stefan Institute, Reactor Engineering Division, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia)

    2013-08-15

    Highlights: ► Grain boundary stiffness should be at least 1.5× higher that the stiffness of bulk grains. ► The ratio δ{sub n}{sup pl}/δ{sub n}{sup el} should be at least 400. ► Simultaneous increase of δ{sub n}{sup el} and δ{sub n}{sup pl} at constant grain boundary strength increases numerical stability but results in high percentage of damage grain boundary area. ► Shear contributes significantly to damage initialization. -- Abstract: In this work a model, based on a X-ray diffraction contrast tomography data of a stainless steel wire with a diameter of 0.4 mm is presented. As measured 3D grain geometry and crystallographic orientation of individual grains are directly transferred into a finite element model. Anisotropic elasticity and crystal plasticity constitutive laws are used for the bulk grain material while the grain boundaries are explicitly modeled using the cohesive zone approach. A parametric study on the effects of the grain boundary strength and other cohesive zone parameters on the macroscopic response and damaged grain boundary area of a polycrystalline aggregate is presented. Recommendations for the cohesive zone parameters values aimed at achieving low damaged grain boundary area during numerical tensile tests are given while at the same time taking into account the numerical stability of the simulations.

  11. An acoustic method for predicting relative strengths of cohesive sediment deposits

    Science.gov (United States)

    Reed, A. H.; Sanders, W. M.

    2017-12-01

    Cohesive sediment dynamics are fundamentally determined by sediment mineralogy, organic matter composition, ionic strength of water, and currents. These factors work to bind the cohesive sediments and to determine depositional rates. Once deposited the sediments exhibit a nonlinear response to stress and they develop increases in shear strength. Shear strength is critically important in resuspension, transport, creep, and failure predictions. Typically, shear strength is determined by point measurements, both indirectly from free-fall penetrometers or directly on cores with a shear vane. These values are then used to interpolate over larger areas. However, the remote determination of these properties would provide continuos coverage, yet it has proven difficult with sonar systems. Recently, findings from an acoustic study on cohesive sediments in a laboratory setting suggests that cohesive sediments may be differentiated using parametric acoustics; this method pulses two primary frequencies into the sediment and the resultant difference frequency is used to determine the degree of acoustic nonlinearity within the sediment. In this study, two marine clay species, kaolinite and montmorillonite, and two biopolymers, guar gum and xanthan gum were mixed to make nine different samples. The samples were evaluated in a parametric acoustic measurement tank. From the parametric acoustic measurements, the quadratic nonlinearity coefficient (beta) was determined. beta was correlated with the cation exchange capacity (CEC), an indicator of shear strength. The results indicate that increased acoustic nonlinearity correlates with increased CEC. From this work, laboratory measurements indicate that this correlation may be used evaluate geotechnical properties of cohesive sediments and may provide a means to predict sediment weakness in subaqueous environments.

  12. Modeling grain boundaries in polycrystals using cohesive elements: Qualitative and quantitative analysis

    Energy Technology Data Exchange (ETDEWEB)

    El Shawish, Samir, E-mail: Samir.ElShawish@ijs.si [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Cizelj, Leon [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Simonovski, Igor [European Commission, DG-JRC, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands)

    2013-08-15

    Highlights: ► We estimate the performance of cohesive elements for modeling grain boundaries. ► We compare the computed stresses in ABAQUS finite element solver. ► Tests are performed in analytical and realistic models of polycrystals. ► Most severe issue is found within the plastic grain response. ► Other identified issues are related to topological constraints in modeling space. -- Abstract: We propose and demonstrate several tests to estimate the performance of the cohesive elements in ABAQUS for modeling grain boundaries in complex spatial structures such as polycrystalline aggregates. The performance of the cohesive elements is checked by comparing the computed stresses with the theoretically predicted values for a homogeneous material under uniaxial tensile loading. Statistical analyses are performed under different loading conditions for two elasto-plastic models of the grains: isotropic elasticity with isotropic hardening plasticity and anisotropic elasticity with crystal plasticity. Tests are conducted on an analytical finite element model generated from Voronoi tessellation as well as on a realistic finite element model of a stainless steel wire. The results of the analyses highlight several issues related to the computation of normal and shear stresses. The most severe issue is found within the plastic grain response where the computed normal stresses on a particularly oriented cohesive elements are significantly underestimated. Other issues are found to be related to topological constraints in the modeling space and result in the increased scatter of the computed stresses.

  13. NON-COHESIVE SOIL DIRECT SHEAR STRENGTH AFFECTED WITH HYDROSTATIC PRESSURE

    Directory of Open Access Journals (Sweden)

    Tadas Tamošiūnas

    2017-12-01

    Full Text Available This paper presents first results of non­cohesive soil direct shear tests with hydrostatic pressure. To reach this aim, it was chosen the Baltic Sea Klaipėda sand, due to granulometry composition and particles shape. According to this, investigated Baltic Sea sand can be called Lithuanian standard sand for scientific testing. Analysis of results revealed, that when it is increased hydrostatic pressure, the shearing strength is also increasing. Comparing air­ dry sand results with fully saturated sand and affected with 100 kPa of hydrostatic pressure, the angle of internal friction increased for 21,24%. Meanwhile, the cohesion was not changing so dramatically according to hydrostatic pressure change. Obtained results allows to proceed this research work more detailed with different loading types, testing procedures and hydrostatic pressures.

  14. An Atomistic Modeling Study of Alloying Element Impurity Element, and Transmutation Products on the cohesion of A Nickel E5 {001} Twist Grain Boundary

    International Nuclear Information System (INIS)

    Young, G.A. Jr.; Najafabadi, R.; Strohmayer, W.; Baldrey, D.G.; Hamm, B.; Harris, J.; Sticht, J.; Wimmer, E.

    2003-01-01

    Atomistic modeling methods were employed to investigate the effects of impurity elements on the metallurgy, irradiation embrittlement, and environmentally assisted cracking of nickel-base alloys exposed to nuclear environments. Calculations were performed via ab initio atomistic modeling methods to ensure the accuracy and reliability of the results. A Griffith-type fracture criterion was used to quantitatively assess the effect of elements or element pairs on the grain boundary cohesive strength. In order of most embrittling to most strengthening, the elements are ranked as: He, Li, S, H, C, Zr, P, Fe, Mn, Nb, Cr, and B. Helium is strongly embrittling (-2.04 eV/atom lowering of the Griffith energy), phosphorus has little effect on the grain boundary (0.1 eV/atom), and boron offers appreciable strengthening (1.03 eV/atom increase in the Griffith energy). Calculations for pairs of elements (H-Li, H-B, H-C, H-P, and H-S) show little interaction on the grain boundary cohesive energy, so that for the conditions studied, linear superposition of elemental effects is a good approximation. These calculations help explain metallurgical effects (e.g. why boron can strengthen grain boundaries), irradiation embrittlement (e.g. how boron transmutation results in grain boundary embrittlement), as well as how grain boundary impurity elements can affect environmentally assisted cracking (i.e. low temperature crack propagation and stress corrosion cracking) of nickel-base alloys

  15. Multiple-Approach Evaluation of WSP Coatings Adhesion/Cohesion Strength

    Czech Academy of Sciences Publication Activity Database

    Mušálek, Radek; Pejchal, V.; Vilémová, Monika; Matějíček, Jiří

    2013-01-01

    Roč. 22, 2-3 (2013), s. 221-232 ISSN 1059-9630. [International Thermal Spray Conference (ITSC). Houston, 21.05.2012-24.05.2012] R&D Projects: GA ČR(CZ) GPP108/12/P552 Institutional research plan: CEZ:AV0Z20430508 Keywords : adhesion testing * adhesive strength * alumina * cohesion * stainless steel * water-stabilized plasma Subject RIV: JI - Composite Materials Impact factor: 1.491, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs11666-012-9850-2.pdf

  16. A cohesive zone model to simulate the hydrogen embrittlement effect on a high-strength steel

    Directory of Open Access Journals (Sweden)

    G. Gobbi

    2016-01-01

    Full Text Available The present work aims to model the fracture mechanical behavior of a high-strength low carbon steel, AISI 4130 operating in hydrogen contaminated environment. The study deals with the development of 2D finite element cohesive zone model (CZM reproducing a toughness test. Along the symmetry plane over the crack path of a C(T specimen a zero thickness layer of cohesive elements are implemented in order to simulate the crack propagation. The main feature of this kind of model is the definition of a traction-separation law (TSL that reproduces the constitutive response of the material inside to the cohesive elements. Starting from a TSL calibrated on hydrogen non-contaminated material, the embrittlement effect is simulated by reducing the cohesive energy according to the total hydrogen content including the lattice sites (NILS and the trapped amount. In this perspective, the proposed model consists of three steps of simulations. First step evaluates the hydrostatic pressure. It drives the initial hydrogen concentration assigned in the second step, a mass diffusion analysis, defining in this way the contribution of hydrogen moving across the interstitial lattice sites. The final stress analysis, allows getting the total hydrogen content, including the trapped amount, and evaluating the new crack initiation and propagation due to the hydrogen presence. The model is implemented in both plane strain and plane stress configurations; results are compared in the discussion. From the analyses, it resulted that hydrogen is located only into lattice sites and not in traps, and that the considered steel experiences a high hydrogen susceptibility. By the proposed procedure, the developed numerical model seems a reliable and quick tool able to estimate the mechanical behavior of steels in presence of hydrogen.

  17. Adhesive and Cohesive Strength in FeB/Fe2B Systems

    Science.gov (United States)

    Meneses-Amador, A.; Blancas-Pérez, D.; Corpus-Mejía, R.; Rodríguez-Castro, G. A.; Martínez-Trinidad, J.; Jiménez-Tinoco, L. F.

    2018-05-01

    In this work, FeB/Fe2B systems were evaluated by the scratch test. The powder-pack boriding process was performed on the surface of AISI M2 steel. The mechanical parameters, such as yield stress and Young's modulus of the boride layer, were obtained by the instrumented indentation technique. Residual stresses produced on the boride layer were estimated by using the x-ray diffraction (XRD) technique. The scratch test was performed in order to evaluate the cohesive/adhesive strength of the FeB/Fe2B coating. In addition, a numerical evaluation of the scratch test on boride layers was performed by the finite element method. Maximum principal stresses were related to the failure mechanisms observed by the experimental scratch test. Shear stresses at the interfaces of the FeB/Fe2B/substrate system were also evaluated. Finally, the results obtained provide essential information about the effect of the layer thickness, the residual stresses, and the resilience modulus on the cohesive/adhesive strength in FeB/Fe2B systems.

  18. Effect of transition metal impurities on the strength of grain boundaries in vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xuebang; Kong, Xiang-Shan; You, Yu-Wei; Liu, Wei; Liu, C. S., E-mail: csliu@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Chen, Jun-Ling; Luo, G.-N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2016-09-07

    Effects of 3d (Ti-Ni), 4d (Zr-Pd), and 5d (Hf-Pt) transition metal impurities on strength of two representative vanadium grain boundaries (GBs), symmetric Σ3(111) and asymmetric Σ5(210), were studied by first-principles calculations within the framework of the Rice-Wang thermodynamic model and within the computational tensile test. The desirable elements to increase the GB cohesion were predicted based on their segregation and strengthening behaviors across the different GB sites. It reveals that the elements Ti, Zr, Hf, Nb, and Ta are good choices for the GB cohesion enhancers. In addition, the GB strengthening by solutes is sensitive to the GB structures. The elements Cr, Mn, Fe, Co, and Ni decrease the GB strength of the Σ3(111) GB but they can increase the cohesion of the Σ5(210) GB. Furthermore, the origin of Ti-induced change of the GB strength was uncovered by analyzing the atomic bonds and electronic structures as well as the tensile strength. This work provides a theoretical guidance to screen promising alloying elements in V-based materials with improved resistance to GB decohesion and also helps us to understand the formation mechanism of Ti-rich precipitates in the V-Cr-Ti alloys under neutron or ion irradiation environments.

  19. Numerical model of glulam beam delamination in dependence on cohesive strength

    Science.gov (United States)

    Kawecki, Bartosz; Podgórski, Jerzy

    2018-01-01

    This paper presents an attempt of using a finite element method for predicting delamination of a glue laminated timber beam through a cohesive layer. There were used cohesive finite elements, quadratic stress damage initiation criterion and mixed mode energy release rate failure model. Finite element damage was equal to its complete stiffness degradation. Timber material was considered to be an orthotropic with plastic behaviour after reaching bending limit.

  20. Income Inequality, Cohesiveness and Commonality in the Euro Area: A Semi-Parametric Boundary-Free Analysis

    Directory of Open Access Journals (Sweden)

    Gordon Anderson

    2018-03-01

    Full Text Available The cohesiveness of constituent nations in a confederation such as the Eurozone depends on their equally shared experiences. In terms of household incomes, commonality of distribution across those constituent nations with that of the Eurozone as an entity in itself is of the essence. Generally, income classification has proceeded by employing “hard”, somewhat arbitrary and contentious boundaries. Here, in an analysis of Eurozone household income distributions over the period 2006–2015, mixture distribution techniques are used to determine the number and size of groups or classes endogenously without resort to such hard boundaries. In so doing, some new indices of polarization, segmentation and commonality of distribution are developed in the context of a decomposition of the Gini coefficient and the roles of, and relationships between, these groups in societal income inequality, poverty, polarization and societal segmentation are examined. What emerges for the Eurozone as an entity is a four-class, increasingly unequal polarizing structure with income growth in all four classes. With regard to individual constituent nation class membership, some advanced, some fell back, with most exhibiting significant polarizing behaviour. However, in the face of increasing overall Eurozone inequality, constituent nations were becoming increasingly similar in distribution, which can be construed as characteristic of a more cohesive society.

  1. Improving the de-agglomeration and dissolution of a poorly water soluble drug by decreasing the agglomerate strength of the cohesive powder.

    Science.gov (United States)

    Allahham, Ayman; Stewart, Peter J; Das, Shyamal C

    2013-11-30

    Influence of ternary, poorly water-soluble components on the agglomerate strength of cohesive indomethacin mixtures during dissolution was studied to explore the relationship between agglomerate strength and extent of de-agglomeration and dissolution of indomethacin (Ind). Dissolution profiles of Ind from 20% Ind-lactose binary mixtures, and ternary mixtures containing additional dibasic calcium phosphate (1% or 10%; DCP), calcium sulphate (10%) and talc (10%) were determined. Agglomerate strength distributions were estimated by Monte Carlo simulation of particle size, work of cohesion and packing fraction distributions. The agglomerate strength of Ind decreased from 1.19 MPa for the binary Ind mixture to 0.84 MPa for 1DCP:20Ind mixture and to 0.42 MPa for 1DCP:2Ind mixture. Both extent of de-agglomeration, demonstrated by the concentration of the dispersed indomethacin distribution, and extent of dispersion, demonstrated by the particle size of the dispersed indomethacin, were in descending order of 1DCP:2Ind>1DCP:20Ind>binary Ind. The addition of calcium sulphate dihydrate and talc also reduced the agglomerate strength and improved de-agglomeration and dispersion of indomethacin. While not definitively causal, the improved de-agglomeration and dispersion of a poorly water soluble drug by poorly water soluble components was related to the agglomerate strength of the cohesive matrix during dissolution. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Cohesion strength and atomic structure of W-Cu graded interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liang, C.P.; Fan, J.L.; Gong, H.R., E-mail: gonghr@csu.edu.cn

    2017-04-15

    W-Cu graded interface is a solution to big differences of properties between W and Cu, while the number and composition of graded layers in the literature are quite different. The present first principles calculation reveals that W-rich graded interfaces possess higher strength and lower interface energy than Cu-rich counterparts. It shows that the differences of thermal expansion and Young’s modulus between overlayer and substrate are decisive factors in the design of Cu-rich and W-rich graded interfaces, respectively. A graded structure of W{sub 8}Cu{sub 1}/W{sub 7}Cu{sub 2}/W{sub 6}Cu{sub 3}/Cu{sub 6}W{sub 3}/Cu{sub 8}W{sub 1} is therefore suggested theoretically.

  3. Adsorption induced losses in interfacial cohesion

    International Nuclear Information System (INIS)

    Asaro, R.J.

    1977-07-01

    A model for interfacial cohesion is developed which describes the loss in the strength of an interface due to the segregation and adsorption of impurities on it. Distinctions are made between interface separations that occur too rapidly for any significant redistribution of adsorbing matter to take place and separations that are slow enough to allow full adsorption equilibrium. Expressions for the total work of complete decohesion are presented for both cases. The results are applied to well-known model adsorption isotherms and some experimental data for grain boundary adsorption of phosphorus in iron is analyzed with respect to the losses in intergranular cohesion

  4. Network cohesion

    OpenAIRE

    Cavalcanti, Tiago Vanderlei; Giannitsarou, Chrysi; Johnson, CR

    2017-01-01

    We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and define a network aggregator that preserves network cohesion.

  5. Development of experimental concepts for investigating the strength behavior of fine-grained cohesive soil in the Spacelab/space shuttle zero-g environment

    Science.gov (United States)

    Bonaparte, R.; Mitchell, J. K.

    1981-01-01

    Three different sets of tests are proposed for the NASA Spacelab experimental program. The first of tests, designed to measure the true cohesion of several different soils, would be carried out in space through use of a specially prepared direct shear apparatus. As part of this first series of tests, it is recommended that a set of drained unconfined compression tests be performed terrestrially on the same soils as tested in space. A form of the direct tension test is planned to measure the true tensile strength of the same types of soils used in the first series of tests. The direct tension tests could be performed terrestrially. The combined results of the direct shear tests, direct tension tests, and unconfined compression tests can be used to construct approximate failure envelopes for the soils tested in the region of the stress origin. Relationships between true cohesion and true tensile strength can also be investigated. In addition, the role of physio-chemical variables should be studied. The third set of tests involves using a multiaxial cubical or true triaxial test apparatus to investigate the influence of gravity induced fabric anisotropy and stress nonhomogeneities on the stress strain behavior of cohesive soils at low effective stress levels. These tests would involve both in space and terrestrial laboratory testing.

  6. Network cohesion

    OpenAIRE

    Cavalcanti, Tiago V. V.; Giannitsarou, Chryssi; Johnson, Charles R.

    2016-01-01

    This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00199-016-0992-1 We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and d...

  7. Development of micro tensile testing method in an FIB system for evaluating grain boundary strength

    International Nuclear Information System (INIS)

    Fujii, Katsuhiko; Fukuya, Koji

    2010-01-01

    A micro tensile testing method for evaluating grain boundary strength was developed. Specimens of 2 x 2 x 10μm having one grain boundary were made by focused ion beam (FIB) micro-processing and tensioned in an FIB system in situ. The load was measured from the deflection of the silicon cantilever. The method was applied to aged and unaged Fe-Mn-P alloy specimens with different level of grain boundary phosphorus segregation. The load at intergranular fracture decreased with increasing phosphorus segregation. (author)

  8. Grain boundary segregation of elements of groups 14 and 15 and its consequences for intergranular cohesion of ferritic iron

    Czech Academy of Sciences Publication Activity Database

    Lejček, Pavel; Šandera, P.; Horníková, J.; Řehák, Petr; Pokluda, J.

    2017-01-01

    Roč. 52, č. 10 (2017), s. 5822-5834 ISSN 0022-2461 R&D Projects: GA ČR GAP108/12/0144; GA MŠk(CZ) LQ1601 Institutional support: RVO:68378271 ; RVO:68081723 Keywords : grain boundary segregation * segregation enthalpy * intergranular fracture * strengthening/embrittling energy Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.599, year: 2016

  9. Effect of grain-boundary crystallization on the high-temperature strength of silicon nitride

    Science.gov (United States)

    Pierce, L. A.; Mieskowski, D. M.; Sanders, W. A.

    1986-01-01

    Si3N4 specimens having the composition 88.7 wt pct Si3N4-4.9 wt pct SiO2-6.4 wt pct Y2O3 were sintered at 2140 C under 25 atm N2 for 1 h and then subjected to a 5 h anneal at 1500 C. Crystallization of an amorphous grain-boundary phase resulted in the formation of Y2Si2O7. The short-time 1370 C strength of this material was compared with that of material of the same composition having no annealing treatment. No change in strength was noted. This is attributed to the refractory nature of the yttrium-rich grain-boundary phase (apparently identical in both glassy and crystalline phases) and the subsequent domination of the failure process by common processing flaws.

  10. Cohesive granular media modelization with non-convex particles shape: Application to UO2 powder compaction

    International Nuclear Information System (INIS)

    Saint-Cyr, B.

    2011-01-01

    We model in this work granular materials composed of non-convex and cohesive aggregates, in view of application to the rheology of UO 2 powders. The effect of non convexity is analyzed in terms of bulk quantities (Coulomb internal friction and cohesion) and micromechanical parameters such as texture anisotropy and force transmission. In particular, we find that the packing fraction evolves in a complex manner with the shape non convexity and the shear strength increases but saturates due to interlocking between the aggregates. We introduce simple models to describe these features in terms of micro-mechanical parameters. Furthermore, a systematic investigation of shearing, uniaxial compaction and simple compression of cohesive packings show that bulk cohesion increases with non-convexity but is strongly influenced by the boundary conditions and shear bands or stress concentration. (author) [fr

  11. Towards a Cohesive Theory of Cohesion

    Directory of Open Access Journals (Sweden)

    Janet McLeod

    2013-12-01

    Full Text Available Conventional wisdom suggests that group cohesion is strongly related to performance. This may be based on the notion that better cohesion leads to the sharing of group goals. However, empirical and meta-analytic studies have been unable to consistently demonstrate a relationship between cohesion and performance. Partially, this problem could be attributed to the disagreement on the precise definition of cohesion and its components. Further, when the cohesion construct is evaluated under Cohen’s Cumulative Research Program (CRP, it is surprisingly found to belong to the category of early-to-intermediate stage of theory development. Therefore, a thorough re-examination of the cohesion construct is essential to advance our understanding of the cohesion-productivity relationship. We propose a qualitative approach because it will help establish the definitions, enable us to better test our theories about cohesion and its moderators, and provide insights into how best to enlist cohesion to improve team performance.

  12. Work and personal life boundary management: boundary strength, work/personal life balance, and the segmentation-integration continuum.

    Science.gov (United States)

    Bulger, Carrie A; Matthews, Russell A; Hoffman, Mark E

    2007-10-01

    While researchers are increasingly interested in understanding the boundaries surrounding the work and personal life domains, few have tested the propositions set forth by theory. Boundary theory proposes that individuals manage the boundaries between work and personal life through processes of segmenting and/or integrating the domains. The authors investigated boundary management profiles of 332 workers in an investigation of the segmentation-integration continuum. Cluster analysis indicated consistent clusters of boundary management practices related to varying segmentation and integration of the work and personal life domains. But, the authors suggest that the segmentation-integration continuum may be more complicated. Results also indicated relationships between boundary management practices and work-personal life interference and work-personal life enhancement. Less flexible and more permeable boundaries were related to more interference, while more flexible and more permeable boundaries were related to more enhancement.

  13. A Study on the Effect of Cohesive Laws on Finite Element Analysis of Crack Propagation Using Cohesive Elements

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyeongseok; Baek, Hyungchan; Kim, Hyungyu [Seoul Nat' l Univ. of Sci. and Tech., Seoul (Korea, Republic of)

    2014-04-15

    In this paper, the effect of cohesive laws on the finite element analysis of crack propagation using cohesive elements is investigated through three-point bending and double cantilever beam problems. The cohesive elements are implemented into ABAQUS/Standard user subroutines(UEL), and the shape of cohesive law is varied by changing parameters in polynomial functions of cohesive traction-separation relations. In particular, crack propagation behaviors are studied by comparing load-displacement curves of the analysis models which have different shapes of cohesive laws with the same values of fracture energy and cohesive strength. Furthermore, the influence of the element size on crack propagation is discussed in this study.

  14. A cohesive zone framework for environmentally assisted fatigue

    DEFF Research Database (Denmark)

    del Busto, Susana; Betegón, Covadonga; Martínez Pañeda, Emilio

    2017-01-01

    We present a compelling finite element framework to model hydrogen assisted fatigue by means of a hydrogen- and cycle-dependent cohesive zone formulation. The model builds upon: (i) appropriate environmental boundary conditions, (ii) a coupled mechanical and hydrogen diffusion response, driven...... by chemical potential gradients, (iii) a mechanical behavior characterized by finite deformation J2 plasticity, (iv) a phenomenological trapping model, (v) an irreversible cohesive zone formulation for fatigue, grounded on continuum damage mechanics, and (vi) a traction-separation law dependent on hydrogen...... coverage calculated from first principles. The computations show that the present scheme appropriately captures the main experimental trends; namely, the sensitivity of fatigue crack growth rates to the loading frequency and the environment. The role of yield strength, work hardening, and constraint...

  15. Assessing Software Quality Through Visualised Cohesion Metrics

    Directory of Open Access Journals (Sweden)

    Timothy Shih

    2001-05-01

    Full Text Available Cohesion is one of the most important factors for software quality as well as maintainability, reliability and reusability. Module cohesion is defined as a quality attribute that seeks for measuring the singleness of the purpose of a module. The module of poor quality can be a serious obstacle to the system quality. In order to design a good software quality, software managers and engineers need to introduce cohesion metrics to measure and produce desirable software. A highly cohesion software is thought to be a desirable constructing. In this paper, we propose a function-oriented cohesion metrics based on the analysis of live variables, live span and the visualization of processing element dependency graph. We give six typical cohesion examples to be measured as our experiments and justification. Therefore, a well-defined, well-normalized, well-visualized and well-experimented cohesion metrics is proposed to indicate and thus enhance software cohesion strength. Furthermore, this cohesion metrics can be easily incorporated with software CASE tool to help software engineers to improve software quality.

  16. Physical properties and strength of cohesive strata from a hazardous area at the Western long-term slope of the Turow surface mine

    Energy Technology Data Exchange (ETDEWEB)

    Konderla, H; Suchnicka, H [Politechnika Wroclawska (Poland)

    1991-01-01

    Evaluates landslide hazards in the Turow brown coal mine in the area of a safety pillar of the Neisse river. Physical and mechanical properties of the following types of rocks from the pillar were investigated under laboratory conditions: cohesive Quaternary strata, clay layers adjacent to the coal seams and separating the seams, weathered and disintegrated granite, basalt and tuff (detritus). Rock samples were tested under conditions of tri-axial stresses, with natural water pore pressure, samples with a natural structure without artificial consolidation. The tests showed intensive fluctuations of rock properties. Nonhomogeneity of the samples and structural disturbances were determined. The tests showed the existence of landslide hazards in the Neisse river area. Recommendations for further investigations are made. 3 refs.

  17. Scour in cohesive soils

    Science.gov (United States)

    2015-05-01

    This study of scour in cohesive soils had two objectives. The first was to introduce and demonstrate a new ex situ erosion testing device (ESTD) that can mimic the near-bed flow of open channels to erode cohesive soils within a specified range of she...

  18. Dynamics of Cohesive Sediments

    DEFF Research Database (Denmark)

    Johansen, Claus

    The present thesis considers the transport processes of cohesive sediments. The cohesive sediment used in the laboratory experiments was kaolinite, a clay mineral, in order to be able to reproduce the individual experiments. In the first part of the thesis, the theoretical considerations regarding...

  19. Strength and Deformation Rate of Plate Boundaries: The Rheological Effects of Grain Size Reduction, Structure, and Serpentinization.

    Science.gov (United States)

    Montesi, L.; Gueydan, F.

    2016-12-01

    Global strain rate maps reveal 1000-fold contrasts between plate interiors, oceanic or continental diffuse plate boundaries and narrow plate boundaries. Here, we show that rheological models based on the concepts of shear zone localization and the evolution of rock structure upon strain can explain these strain rate contrasts. Ductile shear zones constitute a mechanical paradox in the lithosphere. As every plastic deformation mechanism is strain-rate-hardening, ductile rocks are expected to deform at low strain rate and low stress (broad zone of deformation). Localized ductile shear zones require either a localized forcing (locally high stress) or a thermal or structural anomaly in the shear zone; either can be inherited or develop progressively as rocks deform. We previously identified the most effective process at each depth level of the lithosphere. In the upper crust and middle crust, rocks fabric controls localization. Grain size reduction is the most efficient mechanism in the uppermost mantle. This analysis can be generalized to consider a complete lithospheric section. We assume strain rate does not vary with depth and that the depth-integrated strength of the lithospheric does not change over time, as the total force is controlled by external process such as mantle convection and plate and slab buoyancy. Reducing grain size from a coarse value typical of undeformed peridotite to a value in agreement with the stress level (piezometer) while letting that stress vary from depth to depth (the integrated stress remains the same) increases the lithospheric strain rate by about a factor of 1000. This can explain the development of diffuse plate boundaries. The slightly higher strain rate of continental plate boundary may reflect development of a layered rock fabric in the middle crust. Narrow plate boundaries require additional weakening process. The high heat flux near mid-ocean ridge implies a thin lithosphere, which enhances stress (for constant integrated

  20. The Structure of Group Cohesion.

    Science.gov (United States)

    Cota, Albert A.; And Others

    1995-01-01

    Reviews the literature on unidimensional and multidimensional models of cohesion and describes cohesion as a multidimensional construct with primary and secondary dimensions. Found that primary dimensions described the cohesiveness of all or most types of groups, whereas secondary dimensions only described the cohesiveness of specific types of…

  1. Strength Reduction Method for Stability Analysis of Local Discontinuous Rock Mass with Iterative Method of Partitioned Finite Element and Interface Boundary Element

    Directory of Open Access Journals (Sweden)

    Tongchun Li

    2015-01-01

    element is proposed to solve the safety factor of local discontinuous rock mass. Slope system is divided into several continuous bodies and local discontinuous interface boundaries. Each block is treated as a partition of the system and contacted by discontinuous joints. The displacements of blocks are chosen as basic variables and the rigid displacements in the centroid of blocks are chosen as motion variables. The contact forces on interface boundaries and the rigid displacements to the centroid of each body are chosen as mixed variables and solved iteratively using the interface boundary equations. Flexibility matrix is formed through PFE according to the contact states of nodal pairs and spring flexibility is used to reflect the influence of weak structural plane so that nonlinear iteration is only limited to the possible contact region. With cohesion and friction coefficient reduced gradually, the states of all nodal pairs at the open or slip state for the first time are regarded as failure criterion, which can decrease the effect of subjectivity in determining safety factor. Examples are used to verify the validity of the proposed method.

  2. Effect of boundary conditions on the strength and deformability of replicas of natural fractures in welded tuff: Data analysis

    International Nuclear Information System (INIS)

    Wibowo, J.; Amadei, B.; Sture, S.

    1994-04-01

    Assessing the shear behavior of intact rock ampersand rock fractures is an important issue in the design of a potential nuclear waste repository at Yucca Mountain Nevada. Cyclic direct shear experiments were conducted on replicas of three natural fractures and a laboratory-developed tensile fracture of welded tuff. The tests were carried out under constant normal loads or constant normal stiffnesses with different initial normal load levels. Each test consisted of five cycles of forward and reverse shear motion. Based on the results of the shear tests conducted under constant normal load, the shear behavior of the joint replicas tested under constant normal stiffness was predicted by using the graphical analysis method of Saeb (1989), and Amadei and Saeb (1990). Comparison between the predictions and the actual constant stiffness direct shear experiment results can be found in a report by Wibowo et al. (1993b). Results of the constant normal load shear experiments are analyzed using several constitutive models proposed in the rock mechanics literature for joint shear strength, dilatancy, and joint surface damage. It is shown that some of the existing models have limitations. New constitutive models are proposed and are included in a mathematical analysis tool that can be used to predict joint behavior under various boundary conditions

  3. Force Transmission Modes of Non-Cohesive and Cohesive Materials at the Critical State.

    Science.gov (United States)

    Wang, Ji-Peng

    2017-08-31

    This paper investigates the force transmission modes, mainly described by probability density distributions, in non-cohesive dry and cohesive wet granular materials by discrete element modeling. The critical state force transmission patterns are focused on with the contact model effect being analyzed. By shearing relatively dense and loose dry specimens to the critical state in the conventional triaxial loading path, it is observed that there is a unique critical state force transmission mode. There is a universe critical state force distribution pattern for both the normal contact forces and tangential contact forces. Furthermore, it is found that using either the linear Hooke or the non-linear Hertz model does not affect the universe force transmission mode, and it is only related to the grain size distribution. Wet granular materials are also simulated by incorporating a water bridge model. Dense and loose wet granular materials are tested, and the critical state behavior for the wet material is also observed. The critical state strength and void ratio of wet granular materials are higher than those of a non-cohesive material. The critical state inter-particle distribution is altered from that of a non-cohesive material with higher probability in relatively weak forces. Grains in non-cohesive materials are under compressive stresses, and their principal directions are mainly in the axial loading direction. However, for cohesive wet granular materials, some particles are in tension, and the tensile stresses are in the horizontal direction on which the confinement is applied. The additional confinement by the tensile stress explains the macro strength and dilatancy increase in wet samples.

  4. Grain boundary engineering of highly deformable ceramics

    International Nuclear Information System (INIS)

    Mecartney, M.L.

    2000-01-01

    Highly deformable ceramics can be created with the addition of intergranular silicate phases. These amorphous intergranular phases can assist in superplastic deformation by relieving stress concentrations and minimizing grain growth if the appropriate intergranular compositions are selected. Examples from 3Y-TZP and 8Y-CSZ ceramics are discussed. The grain boundary chemistry is analyzed by high resolution analytical TEM is found to have a strong influence on the cohesion of the grains both at high temperature and at room temperature. Intergranular phases with a high ionic character and containing large ions with a relatively weak bond strength appear to cause premature failure. In contrast, intergranular phases with a high degree of covalent character and similar or smaller ions than the ceramic and a high ionic bond strength are the best for grain boundary adhesion and prevention of both cavitation at high temperatures and intergranular fracture at room temperature

  5. Competition and social cohesion

    Directory of Open Access Journals (Sweden)

    Mario Libertini

    2014-03-01

    Full Text Available "Competition" and "social cohesion" are both protected by E.U. and Italian laws. The author moves from the analysis of the meaning of these two concepts, in order to reflect on their compatibility and the way to conciliate them. The central problem - in the opinion of the Author - is to abandon the myth of spontaneous markets' order and to rebuild a political order able to maintain and support, as far as possible, the competitive market economy, but also to govern economic processes in critical moments and situations.

  6. Lithospheric strength in the active boundary between the Pacific Plate and Baja California microplate constrained from lower crustal and upper mantle xenoliths

    Science.gov (United States)

    Chatzaras, Vasileios; van der Werf, Thomas; Kriegsman, Leo M.; Kronenberg, Andreas; Tikoff, Basil; Drury, Martyn R.

    2017-04-01

    The lower crust is the most poorly understood of the lithospheric layers in terms of its rheology, particularly at active plate boundaries. We studied naturally deformed lower crustal xenoliths within an active plate boundary, in order to link their microstructures and rheological parameters to the well-defined active tectonic context. The Baja California shear zone (BCSZ), located at the western boundary of the Baja California microplate, comprises the active boundary accommodating the relative motion between the Pacific plate and Baja California microplate. The basalts of the Holocene San Quintin volcanic field carry lower crustal and upper mantle xenoliths, which sample the Baja California microplate lithosphere in the vicinity of the BCSZ. The lower crustal xenoliths range from undeformed gabbros to granoblastic two-pyroxene granulites. Two-pyroxene geothermometry shows that the granulites equilibrated at temperatures of 690-920 oC. Phase equilibria (P-T pseudosections using Perple_X) indicate that symplectites with intergrown pyroxenes, plagioclase, olivine and spinel formed at 3.6-5.4 kbar, following decompression from pressures exceeding 6 kbar. FTIR spectroscopy shows that the water content of plagioclase varies among the analyzed xenoliths; plagioclase is relatively dry in two xenoliths while one xenolith contains hydrated plagioclase grains. Microstructural observations and analysis of the crystallographic texture provide evidence for deformation of plagioclase by a combination of dislocation creep and grain boundary sliding. To constrain the strength of the lower crust and upper mantle near the BCSZ we estimated the differential stress using plagioclase and olivine grain size paleopiezomtery, respectively. Differential stress estimates for plagioclase range from 10 to 32 MPa and for olivine are 30 MPa. Thus the active microplate boundary records elevated crustal temperatures, heterogeneous levels of hydration, and low strength in both the lower crust and

  7. Leadership, cohesion and groupthink

    Directory of Open Access Journals (Sweden)

    Iurchevici Iulia

    2016-09-01

    Full Text Available The Groupthink Phenomenon refers to the tendency of the members of a group to reach solidarity and cohesion, the trend that makes to bypass any questions which would lead to disputes. In such cases, if the members expect counter-arguments regarding a certain issue, they avoid to raise the matter. If it is believed that a question cannot be answered – it isn’t asked. Originally, Janis the author of the term, explains this process through the environment that has been established within groups that are in the leading position, but later, puts a strong emphasis towards the tendency to maintain the unanimity of the decision of the group. As preceding conditions of this decision-making process are listed the following: the high cohesion of the group, its isolation from other external sources of information, the lack of an impartial leadership, lack of appropriate legal framework and procedures in the decision - making process, and also “homogeneity of members, background and their ideology”. The Groupthink is manifested by: Illusion of Invulnerability, Collective Rationalization, Illusion of morality, Out – Group Stereotypes, Strong pressures towards conformism, Self – Censorship, Illusions of unanimity, and the presence of “Mind Guards”. In order to understand the decisions of a group, it is important that some analysis of Groupthink to be done, because in this way, can be controlled or eliminated the communicational distortion that occurs at a time among members forming these groups.

  8. The Tectonic Boundary Between Eastern Subbaisin and South-West Subbasin of the South China Sea Revealed from the Normalized Magnetic Source Strength

    Science.gov (United States)

    Guo, L.; Meng, X.

    2014-12-01

    The South China Sea (SCS), surrounded by the Eurasia, Pacific and India-Australia plates, is one of the largest marginal seas in the Western Pacific. It was formed by the interaction of the three plates and the seafloor spreading during Late Oligocene time to Early Miocene time. The boundary between Eastern Subbaisin and South-west Subbasin of the SCS has long been debated in the literature. Refining the boundary is one of the crucial tasks for correctly understanding the seafloor spreading model of the SCS. Due to few drills on the deep ocean basin of the SCS, magnetic data become important information for refining the boundary. However, the interpretation of magnetic data in the SCS suffers from the remanent magnetization of ocean crust as well as igneous rock and seamounts. The conventional reduction-to-pole anomalies at low latitudes usually neglect the remanent magnetization, making the interpretation incorrect. Here, we assembled high-resolution total magnetic intensity (TMI) data around the ocean basin of the SCS, and then did a special transformation of the TMI anomalies with a varying magnetic inclinations algorithm to obtain the normalized source strength (NSS). The NSS has advantage of insensitivity to remanent magnetization, benefitting correct interpretation. The NSS presents discriminative features from east to west in the ocean basin. The boundary of the discriminative features is clear and just ranges from the northeastern edge of the Zhongsha Islands running in the southeast direction to the northeastern edge of the Reed Bank. These imply that magnetic structure and tectonic features in the crust are discriminative between both sides of this boundary. It can be deduced that this boundary is the tectonic boundary between Eastern Subbaisin and South-west Subbasin. We acknowledge the financial support of the National Natural Science Foundation of China (41374093) and the SinoProbe-01-05 project.

  9. Properties of grain boundaries in BCC iron and iron-based alloys

    International Nuclear Information System (INIS)

    Terentyev, D.; He, Xinfu

    2010-01-01

    The report contains a summary of work done within the collaboration established between SCK-CEN and CIEA, performed during the internship of Xinfu He (CIAE) in the period of September 2009 to June 2010. In this work, we have carried out an atomistic study addressing the properties of grain boundaries in BCC Fe and Fe-Cr alloys. Throughout this work we report on the structural and cohesive properties of grain boundaries; thermal stability; interaction of grain boundaries with He and diffusivity of He in the core of the grain boundaries; equilibrium segregation of Cr near the grain boundary zone; cleavage fracture of grain boundaries; influence of the Cr precipitates, voids and He bubbles on the structure and strength of grain boundaries.

  10. Properties of grain boundaries in BCC iron and iron-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Terentyev, D.; He, Xinfu

    2010-08-15

    The report contains a summary of work done within the collaboration established between SCK-CEN and CIEA, performed during the internship of Xinfu He (CIAE) in the period of September 2009 to June 2010. In this work, we have carried out an atomistic study addressing the properties of grain boundaries in BCC Fe and Fe-Cr alloys. Throughout this work we report on the structural and cohesive properties of grain boundaries; thermal stability; interaction of grain boundaries with He and diffusivity of He in the core of the grain boundaries; equilibrium segregation of Cr near the grain boundary zone; cleavage fracture of grain boundaries; influence of the Cr precipitates, voids and He bubbles on the structure and strength of grain boundaries.

  11. On Techniques to Characterize and Correlate Grain Size, Grain Boundary Orientation and the Strength of the SiC Layer of TRISO Coated Particles: A Preliminary Study

    Energy Technology Data Exchange (ETDEWEB)

    I.J.van Rooyen; J.L. Dunzik Gougar; T. Trowbridge; Philip M van Rooyen

    2012-10-01

    The mechanical properties of the silicon carbide (SiC) layer of the TRi-ISOtropic (TRISO) coated particle (CP) for high temperature gas reactors (HTGR) are performance parameters that have not yet been standardized by the international HTR community. Presented in this paper are the results of characterizing coated particles to reveal the effect of annealing temperature (1000 to 2100°C) on the strength and grain size of unirradiated coated particles. This work was further expanded to include possible relationships between the grain size and strength values. The comparative results of two strength measurement techniques and grain size measured by the Lineal intercept method are included. Preliminary grain boundary characterization results determined by electron backscatter diffraction (EBSD) are included. These results are also important for future fission product transport studies, as grain boundary diffusion is identified as a possible mechanism by which 110mAg, one of the fission activation products, might be released through intact SiC layers. Temperature is a parameter known to influence the grain size of SiC and therefore it is important to investigate the effect of high temperature annealing on the SiC grain size. Recommendations and future work will also be briefly discussed.

  12. Minimum description length block finder, a method to identify haplotype blocks and to compare the strength of block boundaries.

    Science.gov (United States)

    Mannila, H; Koivisto, M; Perola, M; Varilo, T; Hennah, W; Ekelund, J; Lukk, M; Peltonen, L; Ukkonen, E

    2003-07-01

    We describe a new probabilistic method for finding haplotype blocks that is based on the use of the minimum description length (MDL) principle. We give a rigorous definition of the quality of a segmentation of a genomic region into blocks and describe a dynamic programming algorithm for finding the optimal segmentation with respect to this measure. We also describe a method for finding the probability of a block boundary for each pair of adjacent markers: this gives a tool for evaluating the significance of each block boundary. We have applied the method to the published data of Daly and colleagues. The results expose some problems that exist in the current methods for the evaluation of the significance of predicted block boundaries. Our method, MDL block finder, can be used to compare block borders in different sample sets, and we demonstrate this by applying the MDL-based method to define the block structure in chromosomes from population isolates.

  13. Minimum Description Length Block Finder, a Method to Identify Haplotype Blocks and to Compare the Strength of Block Boundaries

    OpenAIRE

    Mannila, H.; Koivisto, M.; Perola, M.; Varilo, T.; Hennah, W.; Ekelund, J.; Lukk, M.; Peltonen, L.; Ukkonen, E.

    2003-01-01

    We describe a new probabilistic method for finding haplotype blocks that is based on the use of the minimum description length (MDL) principle. We give a rigorous definition of the quality of a segmentation of a genomic region into blocks and describe a dynamic programming algorithm for finding the optimal segmentation with respect to this measure. We also describe a method for finding the probability of a block boundary for each pair of adjacent markers: this gives a tool for evaluating the ...

  14. Immigration, social cohesion, and naturalization

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    social trust do not connect with issues of naturalization at all. Other conceptions of social cohesion are either politically controversial, problematic as part of the justification of stricter naturalization requirements, or in fact justify less demanding naturalization requirements....

  15. Developing Indicators of Territorial Cohesion

    DEFF Research Database (Denmark)

    Gallina, Andrea; Farrugia, Nadia

    setting. The concept of territorial cohesion attaches importance to the diversity of the European territory which is seen as a key competitive advantage, the preservation of the European social model, and the ability of the citizens of Europe's nations and regions to be able to continue to live within...... (EU). The objective of territorial cohesion, which builds on the European Spatial Development Perspective (ESDP), is to help achieve a more balanced development by reducing existing disparities, avoiding territorial imbalances and by making sectoral policies, which have a spatial impact and regional...... policy more coherent. It also aims to improve territorial integration and encourage cooperation between regions. Territorial cohesion complements the notions of economic and social cohesion by translating the fundamental EU goal of a balanced competitiveness and sustainable development into a territorial...

  16. Three dimensional grain boundary modeling in polycrystalline plasticity

    Science.gov (United States)

    Yalçinkaya, Tuncay; Özdemir, Izzet; Fırat, Ali Osman

    2018-05-01

    At grain scale, polycrystalline materials develop heterogeneous plastic deformation fields, localizations and stress concentrations due to variation of grain orientations, geometries and defects. Development of inter-granular stresses due to misorientation are crucial for a range of grain boundary (GB) related failure mechanisms, such as stress corrosion cracking (SCC) and fatigue cracking. Local crystal plasticity finite element modelling of polycrystalline metals at micron scale results in stress jumps at the grain boundaries. Moreover, the concepts such as the transmission of dislocations between grains and strength of the grain boundaries are not included in the modelling. The higher order strain gradient crystal plasticity modelling approaches offer the possibility of defining grain boundary conditions. However, these conditions are mostly not dependent on misorientation of grains and can define only extreme cases. For a proper definition of grain boundary behavior in plasticity, a model for grain boundary behavior should be incorporated into the plasticity framework. In this context, a particular grain boundary model ([l]) is incorporated into a strain gradient crystal plasticity framework ([2]). In a 3-D setting, both bulk and grain boundary models are implemented as user-defined elements in Abaqus. The strain gradient crystal plasticity model works in the bulk elements and considers displacements and plastic slips as degree of freedoms. Interface elements model the plastic slip behavior, yet they do not possess any kind of mechanical cohesive behavior. The physical aspects of grain boundaries and the performance of the model are addressed through numerical examples.

  17. Cohesive zone modeling of intergranular cracking in polycrystalline aggregates

    International Nuclear Information System (INIS)

    Simonovski, Igor; Cizelj, Leon

    2015-01-01

    Highlights: • Alternative approach to cohesive elements is proposed: cohesive-zone contact. • Applicability to measured and simulated grain structures is demonstrated. • Normal and normal/shear separation as a damage initialization is explored. • Normal/shear damage initialization significantly reduces ductility. • Little difference in Voronoi aggregate size on macroscopic response. - Abstract: Understanding and controlling early damage initiation and evolution are amongst the most important challenges in nuclear power plants, occurring in ferritic, austenitic steels and nickel based alloys. In this work a meso-scale approach to modeling initiation and evolution of early intergranular cracking is presented. This damage mechanism is present in a number of nuclear power plant components and depends on the material (e.g. composition, heat treatment, microstructure), environment and load. Finite element modeling is used to explicitly model the microstructure – both the grains and the grain boundaries. Spatial Voronoi tessellation is used to obtain the grain topology. In addition, measured topology of a 0.4 mm stainless steel wire is used. Anisotropic elasticity and crystal plasticity are used as constitutive laws for the grains. Grain boundaries are modeled using the cohesive zone approach. Different modeling assumptions/parameters are evaluated against the numerical stability criteria. The biggest positive contribution to numerical stability is the use of cohesive-type contact instead of cohesive elements. A small amount of viscous regularization should be also used along with the addition of a small amount of viscous forces to the global equilibrium equations. Two cases of grain boundary damage initiation are explored: (1) initiation due to normal separation and (2) initiation due to a combination of normal and shear separation. The second criterion significantly decreases the ductility of an aggregate and slightly improves the numerical stability

  18. Effect of boundary conditions on the strength and deformability of replicas of natural fractures in welded tuff

    International Nuclear Information System (INIS)

    Wibowo, J.; Amadei, B.; Sture, S.; Robertson, A.B.

    1993-09-01

    Four series of cyclic direct-shear experiments were conducted on several replicas of three natural fractures and a tensile fracture of welded tuff from Yucca Mountain. The objective of these tests was to examine the effect of cyclic loading on joint shear behavior under different boundary conditions. The shear tests were performed under either different levels of constant normal load ranging between 0.6 and 25.6 kips (2.7 and 113.9 kN) or constant normal stiffness ranging between 14.8 and 187.5 kips/in (25.9 and 328.1 kn/cm) . Bach test in the two categories consisted of five cycles of forward and reverse shear. Normal compression tests were also performed both before and after each shear experiment to measure changes in joint normal deformability. In order to quantify fracture surface damage during shear, fracture-surface fractal dimensions were obtained from measurements before and after shear

  19. Selective role of bainitic lath boundary in influencing slip systems and consequent deformation mechanisms and delamination in high-strength low-alloy steel

    Science.gov (United States)

    Liu, S.; Li, X.; Guo, H.; Yang, S.; Wang, X.; Shang, C.; Misra, R. D. K.

    2018-04-01

    We elucidate here the deformation behaviour and delamination phenomenon in a high-strength low-alloy bainitic steel, in terms of microstructure, texture and stress evolution during deformation via in situ electron back-scattered diffraction and electron microscopy. Furthermore, the selective role of bainitic lath boundary on slip systems was studied in terms of dislocation pile-up and grain boundary energy models. During tensile deformation, the texture evolution was concentrated at {1 1 0} and the laths were turn parallel to loading direction. The determining role of lath on the deformation behaviour is governed by length/thickness (l/t) ratio. When l/t > 28, the strain accommodates along the bainite lath rather than along the normal direction. The delamination crack initiated normal to (0 1 1) plane, and become inclined to (0 1 1) plane with continued strain along (0 1 1) plane and lath plane. This indicated that the delamination is not brittle process but plastic process. The lack of dimples at the delaminated surface is because of lack of strain normal to the direction of lath. The delaminated (0 1 1) planes were associated with cleavage along the (1 0 0) plane.

  20. The influence of electrical resistivity, magnetic field strength, boundary conditions, and injection conditions on the behavior of the magnetically injected plasma in the PBFA-II opening switch

    International Nuclear Information System (INIS)

    Watrous, J.J.; Frese, M.H.

    1993-01-01

    The Plasma Opening Switch used on PBFA-II uses a source plasma which is injected into the inter-electrode gap along the field lines of a modest-strength applied poloidal magnetic field. The distribution of this plasma within the gap plays an important role in the behavior of the switch. Knowledge of this distribution is critical for performing relevant switch calculations and for interpreting experimental data. In the work reported here, the influence on that distribution of the plasma electrical resistivity, the applied magnetic field strength, and the boundary and injection conditions have been investigated with the 2 1/2-dimensional magnetohydrodynamics simulation code, MACH2. The injected plasma has density in the 10 14 cm -3 range and temperature in the several eV range. In this parameter regime, the classical collision time scale is on the order of 10 ns, which, when compared to the 100 ns time scale of the inflowing plasma, means that the plasma is classically collisionless. However, mechanisms other than classical collisions are likely to contribute to electrical resistivity. The authors have investigated the effect of an anomalous resistivity which scales with the plasma frequency, varying the scaling from the electron plasma frequency to the ion plasma frequency. They will compare these results with results based on the assumption of an ideal plasma, and discuss other anomalous resistivity models

  1. Forms of cohesion in confinement institutions

    Directory of Open Access Journals (Sweden)

    Ekaterina D. Slobodenyuk

    2015-12-01

    Full Text Available Objective to identify the diversity of cohesion forms in confinement institutions. Methods qualitative analyses based on indepth semistructured interviews. Results the study included adaptation of Western methodologies of the cohesion phenomenon analysis to the Russian reality and operationalization of the moral bases of group cohesion. This served as the bases for designing a guide for indepth semistructured interviews 10 interviews were conducted with people recently released from general and strict regime colonies. Content analysis of the interviews revealed a number of structural sections that demonstrate the diversity of cohesion forms alongside with one that is most meaningful to the prisoners and therefore the most well perceived and articulated by respondents. Analysis of the latter allowed to identify a set of groups showing different degree and nature of cohesion. By the degree of cohesion one can identify the poorly cohesive groups quotloutsquot moderately cohesive quotredsquot quotthievesquot and highly cohesive quotfightersquot. By the nature of cohesion in the prisonersrsquo community there are both groups united on the basis of social morality quotredsquot quotthievesquot and groups demonstrating a high degree of cohesion based on the social justice morality quotfightersquot. A detailed analysis of the latter group also showed that the cohesion can have both traits of morality social justice and features of social order moral. Scientific novelty using the sociopsychological theory of the moral motives in determining the bases of cohesion. Practical significance the research results can be applied for the development of sociopsychological techniques for the penal system reform.

  2. Grain Boundary Segregation in Metals

    CERN Document Server

    Lejcek, Pavel

    2010-01-01

    Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.

  3. Auto consolidated cohesive sediments erosion

    International Nuclear Information System (INIS)

    Ternat, F.

    2007-02-01

    Pollutants and suspended matters of a river can accumulate into the sedimentary column. Once deposited, they are submitted to self-weight consolidation processes, ageing and burying, leading to an increase of their erosion resistance. Pollutant fluxes can be related to sedimentary fluxes, determined by threshold laws. In this work, an erosion threshold model is suggested by introducing a cohesion force into the usual force balance. A model of cohesion is developed on the basis of interactions between argillaceous cohesive particles (clays), particularly the Van der Waals force, whose parameterization is ensured by means of granulometry and porosity. Artificial erosion experiments were performed in a recirculating erosion flume with natural cored sediments where critical shear stress measurements were performed. Other analyses provided granulometry and porosity. The results obtained constitute a good database for the literature. The model is then applied to the experimental conditions and gives good agreement with measurements. An example of the accounting for self-weight consolidation processes is finally suggested, before finishing on a Mohr like diagram dedicated to soft cohesive sediment erosion. (author)

  4. Flocculation Dynamics of cohesive sediment

    NARCIS (Netherlands)

    Maggi, F.

    2005-01-01

    Cohesive sediment suspended in natural waters is subject not only to transport and deposition processes but also to reactions of flocculation, \\textit{i.e.} aggregation of fine particles, and breakup of aggregates. Although aggregation and breakup occur at small and very small length scales compared

  5. Grain boundary structure and properties

    International Nuclear Information System (INIS)

    Balluffi, R.W.

    1979-01-01

    An attempt is made to distinguish those fundamental aspects of grain boundaries which should be relevant to the problem of the time dependent fracture of high temperature structural materials. These include the basic phenomena which are thought to be associated with cavitation and cracking at grain boundaries during service and with the more general microstructural changes which occur during both processing and service. A very brief discussion of the current state of our knowledge of these fundamentals is given. Included are the following: (1) structure of ideal perfect boundaries; (2) defect structure of grain boundaries; (3) diffusion at grain boundaries; (4) grain boundaries as sources/sinks for point defects; (5) grain boundary migration; (6) dislocation phenomena at grain boundaries; (7) atomic bonding and cohesion at grain boundaries; (8) non-equilibrium properties of grain boundaries; and (9) techniques for studying grain boundaries

  6. Psychological characteristics of group cohesion athletes.

    OpenAIRE

    Sheriff Sarhan

    2011-01-01

    The basic components of group cohesion in sport teams. An analysis of publications on cohesion within the groups where an interconnection of individual goals of each participant group with common goals and the end result of teamwork. The concept of harmony in the team sports, where the rate of group cohesion is dependent on such integrative index as psychological climate. It is established that a number of athletes to achieve high results require high cohesion, unity, value-normative orientat...

  7. Numerical simulation of fatigue crack growth rate and crack retardation due to an overload using a cohesive zone model

    NARCIS (Netherlands)

    Silitonga, S.; Maljaars, J.; Soetens, F.; Snijder, H.H.

    2014-01-01

    In this work, a numerical method is pursued based on a cohesive zone model (CZM). The method is aimed at simulating fatigue crack growth as well as crack growth retardation due to an overload. In this cohesive zone model, the degradation of the material strength is represented by a variation of the

  8. Grain-resolving simulations of settling cohesive sediment

    Science.gov (United States)

    Vowinckel, Bernhard; Whithers, Jade; Meiburg, Eckart; Luzzatto-Fegiz, Paolo

    2017-11-01

    Cohesive sediment is ubiquitous in natural environments such as rivers, lakes and coastal ecosystems. For this type of sediment, we can no longer ignore the short-range attractive forces that result in flocculation of aggregates much larger than the individual grain size. Hence, understanding the complex dynamics of the interplay between flocculated sediment and the ambient fluid is of prime interest for managing aquatic environments, although a comprehensive understanding of these phenomena is still lacking. In the present study, we address this issue by carrying out grain-resolved simulations of cohesive particles settling under gravity using the Immersed Boundary Method. We present a computational model formulation to accurately resolve the process of flocculation. The cohesive model is then applied to a complex test case. A randomly distributed ensemble of 1261 polydisperse particles is released in a tank of quiescent fluid. Subsequently, particles start to settle, thereby replacing fluid at the bottom of the tank, which induces a counter flow opposing the settling direction. This mechanism will be compared to experimental studies from the literature, as well as to the non-cohesive counterpart to assessthe impact of flocculation on sedimentation.

  9. SeLeCT: a lexical cohesion based news story segmentation system

    OpenAIRE

    Stokes, Nicola; Carthy, Joe; Smeaton, Alan F.

    2004-01-01

    In this paper we compare the performance of three distinct approaches to lexical cohesion based text segmentation. Most work in this area has focused on the discovery of textual units that discuss subtopic structure within documents. In contrast our segmentation task requires the discovery of topical units of text i.e., distinct news stories from broadcast news programmes. Our approach to news story segmentation (the SeLeCT system) is based on an analysis of lexical cohesive strength between ...

  10. The effect of biological cohesion on current ripple development

    Science.gov (United States)

    Malarkey, Jonathan; Baas, Jaco H.; Hope, Julie

    2014-05-01

    contrast, the biological cohesion experiments resulted in a drastic slowing down in ripple development, for much smaller amounts of xanthan (Research Council (NERC) under the 'COHBED' project (NE/1027223/1). REFERENCES Baas, J.H., Davies, A.G. and Malarkey, A.G. (2013) Bedform development in mixed sand-mud: the contrasting role of cohesive forces in flow and bed. Geomorphology, 182, 19-32. Grant, J. and Gust, G. (1987) Prediction of coastal sediment stability from photopigment content of mats of purple sulfur bacteria. Nature, 330, 244-246. Vardy, S., Saunders, J.E., Tolhurst, T.J., Davies, P.A., and Paterson, D.M. (2007) Calibration of the high-pressure cohesive strength meter (CSM). Continental Shelf Research, 27, 1190-1199.

  11. Cohesion and coordination effects on transition metal surface energies

    Science.gov (United States)

    Ruvireta, Judit; Vega, Lorena; Viñes, Francesc

    2017-10-01

    Here we explore the accuracy of Stefan equation and broken-bond model semiempirical approaches to obtain surface energies on transition metals. Cohesive factors are accounted for either via the vaporization enthalpies, as proposed in Stefan equation, or via cohesive energies, as employed in the broken-bond model. Coordination effects are considered including the saturation degree, as suggested in Stefan equation, employing Coordination Numbers (CN), or as the ratio of broken bonds, according to the bond-cutting model, considering as well the square root dependency of the bond strength on CN. Further, generalized coordination numbers CN bar are contemplated as well, exploring a total number of 12 semiempirical formulations on the three most densely packed surfaces of 3d, 4d, and 5d Transition Metals (TMs) displaying face-centered cubic (fcc), body-centered cubic (bcc), or hexagonal close-packed (hcp) crystallographic structures. Estimates are compared to available experimental surface energies obtained extrapolated to zero temperature. Results reveal that Stefan formula cohesive and coordination dependencies are only qualitative suited, but unadvised for quantitative discussion, as surface energies are highly overestimated, favoring in addition the stability of under-coordinated surfaces. Broken-bond cohesion and coordination dependencies are a suited basis for quantitative comparison, where square-root dependencies on CN to account for bond weakening are sensibly worse. An analysis using Wulff shaped averaged surface energies suggests the employment of broken-bond model using CN to gain surface energies for TMs, likely applicable to other metals.

  12. Eight-year follow-up data from the U.S. clinical trial for Sientra's FDA-approved round and shaped implants with high-strength cohesive silicone gel.

    Science.gov (United States)

    Stevens, W Grant; Harrington, Jennifer; Alizadeh, Kaveh; Broadway, David; Zeidler, Kamakshi; Godinez, Tess B

    2015-05-01

    On March 9, 2012, the Food and Drug Administration (FDA) approved Sientra's premarket approval application for its portfolio of silicone gel breast implants based on their review of Sientra's 3-year study data from the largest pivotal silicone gel breast implant study to date. This included the first approval of shaped breast implants in the United States. The authors provide an update to the 8-year safety and effectiveness of the Sientra High-Strength silicone gel breast implants. The Sientra Core study is an ongoing 10 year open-label, prospective, multi-center clinical study, which includes 1788 patients implanted with 3506 Sientra implants across four indications (Primary Augmentation, Revision Augmentation, Primary Reconstruction, and Revision Reconstruction). For the safety analysis, the incidence of post-operative complications, including all breast implant-related adverse effects (eg, infection, asymmetry), was estimated based on Kaplan-Meier risk rates. The effectiveness analyses include surgeon and patient satisfaction and changes in bra/cup size. Through 8 years, the overall risk of rupture was 4.6%, the risk of capsular contracture was 11.8% (rates were lower when using True Texture™), and the risk of reoperation was 28.3%. Out of the 580 reoperations in 456 patients, over half of all reoperations were due to cosmetic reasons (n = 299). The most common reasons for reoperation were capsular contracture (19.0%), style and/or size change (18.4%), and asymmetry (8.8%). Patient satisfaction remains high through 8 years, with 87% indicating that their breast implants make them feel more feminine than prior to enrollment. Safety data from the FDA Core study continues to support a comprehensive safety and effectiveness profile of Sientra's portfolio of round and shaped implants through 8 years. 3 Therapeutic. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  13. Simulation of debonding in Al/epoxy T-peel joints using a potential-based cohesive zone model

    KAUST Repository

    Alfano, Marco; Furgiuele, Franco; Lubineau, Gilles; Paulino, Glaucio H.

    2011-01-01

    In this work, a cohesive zone model of fracture is employed to study debonding in plastically deforming Al/epoxy T-peel joints. In order to model the adhesion between the bonded metal strips, the Park-Paulino-Roesler (PPR) potential based cohesive model (J Mech Phys Solids, 2009;57:891-908) is employed, and interface elements are implemented in a finite element com-mercial code. A study on the influence of the cohesive properties (i.e. cohesive strength, fracture energy, shape parameter and slope indicator) on the predicted peel-force versus displacement plots reveals that the numerical results are mostly sensitive to cohesive strength and fracture energy. In turn, these parameters are tuned until a match between experimental and simulated load displacement curves is achieved.

  14. Simulation of debonding in Al/epoxy T-peel joints using a potential-based cohesive zone model

    KAUST Repository

    Alfano, Marco

    2011-06-10

    In this work, a cohesive zone model of fracture is employed to study debonding in plastically deforming Al/epoxy T-peel joints. In order to model the adhesion between the bonded metal strips, the Park-Paulino-Roesler (PPR) potential based cohesive model (J Mech Phys Solids, 2009;57:891-908) is employed, and interface elements are implemented in a finite element com-mercial code. A study on the influence of the cohesive properties (i.e. cohesive strength, fracture energy, shape parameter and slope indicator) on the predicted peel-force versus displacement plots reveals that the numerical results are mostly sensitive to cohesive strength and fracture energy. In turn, these parameters are tuned until a match between experimental and simulated load displacement curves is achieved.

  15. Grain boundaries and mechanical properties of nanocrystalline diamond films.

    Energy Technology Data Exchange (ETDEWEB)

    Busmann, H.-G.; Pageler, A.; Gruen, D. M.

    1999-08-06

    Phase-pure nanocrystalline diamond thin films grown from plasmas of a hydrogen-poor carbon argon gas mixture have been analyzed regarding their hardness and elastic moduli by means of a microindentor and a scanning acoustic microscope.The films are superhard and the moduli rival single crystal diamond. In addition, Raman spectroscopy with an excitation wavelength of 1064 nm shows a peak at 1438 l/cm and no peak above 1500 l/cm, and X-ray photoelectron spectroscopy a shake-up loss at 4.2 eV. This gives strong evidence for the existence of solitary double bonds in the films. The hardness and elasticity of the films then are explained by the assumption, that the solitary double bonds interconnect the nanocrystals in the films, leading to an intergrain boundary adhesion of similar strength as the intragrain diamond cohesion. The results are in good agreement with recent simulations of high-energy grain boundaries.

  16. Cohesion Policy Contributing to Territorial Cohesion – Future Scenarios

    Directory of Open Access Journals (Sweden)

    Andreas Faludi

    2011-09-01

    Full Text Available The Barca Report advocates for developmental policies to be ‘place-based’: integrated as far as they affect ‘places’. The debate on territorial cohesion is equally concerned with integrating relevant policies and actions. This requires well-established democratic institutions and adequate responses to the demands of technical systems and of markets. Following Lisbeth Hooghe and Gary Marks, the respective arrangements are described as Governance Type I and Type II. All levels of government, including that of the EU, partake in both types, but relations between them are problematic, particularly in the context of Europe 2020: Will this EU strategy be mainly a matter for Directorate-Generals and their various clients pursuing their policies (Governance Type II, or will Cohesion policy, with its more integrated and decentralised approach, involving many levels of government and stakeholders (Governance Type I form platforms for integrating them? This paper presents four scenarios; each based on a combination of strong/weak Governance Type I and Type II, which are labelled as the ‘Anglo-Saxon’, ‘Saint-Simonian’, ‘Rhineland’ and the ‘European’ Scenarios. The authors prefer the latter, but the best one can hope for in the short term is for this option not to fall by the wayside.

  17. Team cohesion and team success in sport.

    Science.gov (United States)

    Carron, Albert V; Bray, Steven R; Eys, Mark A

    2002-02-01

    The main aim of this study was to examine the relationship between task cohesiveness and team success in elite teams using composite team estimates of cohesion. A secondary aim was to determine statistically the consistency (i.e. 'groupness') present in team members' perceptions of cohesion. Elite university basketball teams (n = 18) and club soccer teams (n = 9) were assessed for cohesiveness and winning percentages. Measures were recorded towards the end of each team's competitive season. Our results indicate that cohesiveness is a shared perception, thereby providing statistical support for the use of composite team scores. Further analyses indicated a strong relationship between cohesion and success (r = 0.55-0.67). Further research using multi-level statistical techniques is recommended.

  18. Sustaining exercise participation through group cohesion.

    Science.gov (United States)

    Estabrooks, P A

    2000-04-01

    The general hypothesis to be examined by this article is that increased group cohesion leads to an increase in adherence to an exercise program over time. Although preliminary research is promising, there is a need for further research aimed at examining the model of group development in exercise classes, the impact of group cohesion on both group and individual exercise behavior, and the measurement of group cohesion.

  19. Psychological characteristics of group cohesion athletes.

    Directory of Open Access Journals (Sweden)

    Sheriff Sarhan

    2011-07-01

    Full Text Available The basic components of group cohesion in sport teams. An analysis of publications on cohesion within the groups where an interconnection of individual goals of each participant group with common goals and the end result of teamwork. The concept of harmony in the team sports, where the rate of group cohesion is dependent on such integrative index as psychological climate. It is established that a number of athletes to achieve high results require high cohesion, unity, value-normative orientation, deep identification and responsibility for the results of the joint group activities.

  20. Regions and the Territorial Cohesion

    Directory of Open Access Journals (Sweden)

    Ioan Ianos

    2013-08-01

    Full Text Available Territorial cohesion is an important target of European Union, constantly promoted by its institutions and their representatives. In the context of the Europe 2020 strategy, one of the most important support documents, the region represents a very important issue, being considered to be the key to its successfulness. The region is seen as a support for the smart growth and all the operational policy concepts try to make use of the spatial potential, by taking better account of the territorial specificities. Two main questions play attention: the need to transform the present-day developmental regions into administrative ones is a priority? What kind of regionalization it must to be promoted? Correlating these issues with already defined territorial cohesion, the administrative region is a real tool for the future territorial development. The experience of the last 14 years asks urgently the building of a new territorial administrative reform, giving competences to regions. For instant, each development region is a construction resulted from a free association of the counties. Their role in the regional development is much reduced one, because their regional councils are not elected; decisions taken at this level are consultative for the social, economical, cultural or political actors.

  1. Drinking water biofilm cohesiveness changes under chlorination or hydrodynamic stress.

    Science.gov (United States)

    Mathieu, L; Bertrand, I; Abe, Y; Angel, E; Block, J C; Skali-Lami, S; Francius, G

    2014-05-15

    Attempts at removal of drinking water biofilms rely on various preventive and curative strategies such as nutrient reduction in drinking water, disinfection or water flushing, which have demonstrated limited efficiency. The main reason for these failures is the cohesiveness of the biofilm driven by the physico-chemical properties of its exopolymeric matrix (EPS). Effective cleaning procedures should break up the matrix and/or change the elastic properties of bacterial biofilms. The aim of this study was to evaluate the change in the cohesive strength of two-month-old drinking water biofilms under increasing hydrodynamic shear stress τw (from ∼0.2 to ∼10 Pa) and shock chlorination (applied concentration at T0: 10 mg Cl2/L; 60 min contact time). Biofilm erosion (cell loss per unit surface area) and cohesiveness (changes in the detachment shear stress and cluster volumes measured by atomic force microscopy (AFM)) were studied. When rapidly increasing the hydrodynamic constraint, biofilm removal was found to be dependent on a dual process of erosion and coalescence of the biofilm clusters. Indeed, 56% of the biofilm cells were removed with, concomitantly, a decrease in the number of the 50-300 μm(3) clusters and an increase in the number of the smaller (i.e., 600 μm(3)) ones. Moreover, AFM evidenced the strengthening of the biofilm structure along with the doubling of the number of contact points, NC, per cluster volume unit following the hydrodynamic disturbance. This suggests that the compactness of the biofilm exopolymers increases with hydrodynamic stress. Shock chlorination removed cells (-75%) from the biofilm while reducing the volume of biofilm clusters. Oxidation stress resulted in a decrease in the cohesive strength profile of the remaining drinking water biofilms linked to a reduction in the number of contact points within the biofilm network structure in particular for the largest biofilm cluster volumes (>200 μm(3)). Changes in the cohesive

  2. Why are Rich Countries more Politically Cohesive?

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Olsson, Ola

    of other groups in society. If the gains from specialization become sufficiently large, however, a market economy will emerge. From being essentially non-cohesive under self-sufficiency, the political decision making process becomes cohesive in the market economy, as the welfare of individuals...

  3. Education and Social Cohesion: Higher Education

    Science.gov (United States)

    Moiseyenko, Olena

    2005-01-01

    Social cohesion is understood as the social networks and the norms of reciprocity and trustworthiness that arise from connections among individuals. When students attend higher education institutions, they go through a process of socialization, and it is vital to ensure that they acquire the core values that underpin the social cohesion. This…

  4. Transfer and Cohesion in Interdisciplinary Education

    Directory of Open Access Journals (Sweden)

    Søren Harnow Klausen

    2014-06-01

    Full Text Available One of the great challenges of interdisciplinary education is to create sufficient cohesion between disciplines. It is suggested that cohesion depends on the transfer of knowledge (in a broad sense, which includes skill and competences among the disciplines involved. Some of the most characteristic types of such transfer are identified and analyzed: Transfer of factual knowledge, theories, methods, models, skills, modes of collaboration and organization, meta-competences, disciplinary self-consciousness, problem selection, framework construction and motivation. Though some of these types of transfer may have a greater or smaller potential for creating cohesion, different kinds of cohesion may serve different interests, and there is no reason to assume that e.g. joint problem solving or theoretical integration should be more conducive to cohesion than e.g. contributions to motivation or disciplinary self-consciousness.

  5. Disaggregation of small, cohesive rubble pile asteroids due to YORP

    Science.gov (United States)

    Scheeres, D. J.

    2018-04-01

    The implication of small amounts of cohesion within relatively small rubble pile asteroids is investigated with regard to their evolution under the persistent presence of the YORP effect. We find that below a characteristic size, which is a function of cohesive strength, density and other properties, rubble pile asteroids can enter a "disaggregation phase" in which they are subject to repeated fissions after which the formation of a stabilizing binary system is not possible. Once this threshold is passed rubble pile asteroids may be disaggregated into their constituent components within a finite time span. These constituent components will have their own spin limits - albeit potentially at a much higher spin rate due to the greater strength of a monolithic body. The implications of this prediction are discussed and include modification of size distributions, prevalence of monolithic bodies among meteoroids and the lifetime of small rubble pile bodies in the solar system. The theory is then used to place constraints on the strength of binary asteroids characterized as a function of their type.

  6. Molecular-dynamics Simulation-based Cohesive Zone Representation of Intergranular Fracture Processes in Aluminum

    Science.gov (United States)

    Yamakov, Vesselin I.; Saether, Erik; Phillips, Dawn R.; Glaessgen, Edward H.

    2006-01-01

    A traction-displacement relationship that may be embedded into a cohesive zone model for microscale problems of intergranular fracture is extracted from atomistic molecular-dynamics simulations. A molecular-dynamics model for crack propagation under steady-state conditions is developed to analyze intergranular fracture along a flat 99 [1 1 0] symmetric tilt grain boundary in aluminum. Under hydrostatic tensile load, the simulation reveals asymmetric crack propagation in the two opposite directions along the grain boundary. In one direction, the crack propagates in a brittle manner by cleavage with very little or no dislocation emission, and in the other direction, the propagation is ductile through the mechanism of deformation twinning. This behavior is consistent with the Rice criterion for cleavage vs. dislocation blunting transition at the crack tip. The preference for twinning to dislocation slip is in agreement with the predictions of the Tadmor and Hai criterion. A comparison with finite element calculations shows that while the stress field around the brittle crack tip follows the expected elastic solution for the given boundary conditions of the model, the stress field around the twinning crack tip has a strong plastic contribution. Through the definition of a Cohesive-Zone-Volume-Element an atomistic analog to a continuum cohesive zone model element - the results from the molecular-dynamics simulation are recast to obtain an average continuum traction-displacement relationship to represent cohesive zone interaction along a characteristic length of the grain boundary interface for the cases of ductile and brittle decohesion. Keywords: Crack-tip plasticity; Cohesive zone model; Grain boundary decohesion; Intergranular fracture; Molecular-dynamics simulation

  7. Investigating the relationship between leader behaviours and group cohesion within women's walking groups.

    Science.gov (United States)

    Caperchione, Cristina; Mummery, W Kerry; Duncan, Mitch

    2011-07-01

    Early research has shown that leadership behaviour is viewed as a crucial factor in successfully developing team cohesion, effectively resulting in greater team satisfaction and more positive team outcomes. However, little is understood if these same factors have an impact on physical activity groups. The purpose of this study was to investigate the relationship between leader behaviours and group cohesiveness within women's physical activity groups. Participants (N = 95) included a sub-sample of adult women who were previously involved in a women's physical activity/walking program. Participants assessed their groups' leader behaviour using items pertaining to enthusiasm, motivation, instruction and availability, and their groups' cohesiveness using the Physical Activity Group Environment Questionnaire (PAGEQ). Canonical correlation analysis was used to determine the strength of association between the four concepts of group cohesion (ATG-T, ATG-S, GI-T and GI-S) and the four items pertaining to leadership behaviour. A significant multivariate relationship was revealed between group cohesion and leadership behaviour, Wilks' lambda = 0.43, F(16,170) = 5.16, p cohesion. Although a cause-effect relationship cannot be determined, the current study can serve as a valuable template in guiding future research in examining potential mechanisms that may assist with physical activity sustainability. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  8. Neighborhood cohesion, neighborhood disorder, and cardiometabolic risk.

    Science.gov (United States)

    Robinette, Jennifer W; Charles, Susan T; Gruenewald, Tara L

    2018-02-01

    Perceptions of neighborhood disorder (trash, vandalism) and cohesion (neighbors trust one another) are related to residents' health. Affective and behavioral factors have been identified, but often in studies using geographically select samples. We use a nationally representative sample (n = 9032) of United States older adults from the Health and Retirement Study to examine cardiometabolic risk in relation to perceptions of neighborhood cohesion and disorder. Lower cohesion is significantly related to greater cardiometabolic risk in 2006/2008 and predicts greater risk four years later (2010/2012). The longitudinal relation is partially accounted for by anxiety and physical activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Natural disasters and indicators of social cohesion.

    Science.gov (United States)

    Calo-Blanco, Aitor; Kovářík, Jaromír; Mengel, Friederike; Romero, José Gabriel

    2017-01-01

    Do adversarial environmental conditions create social cohesion? We provide new answers to this question by exploiting spatial and temporal variation in exposure to earthquakes across Chile. Using a variety of methods and controlling for a number of socio-economic variables, we find that exposure to earthquakes has a positive effect on several indicators of social cohesion. Social cohesion increases after a big earthquake and slowly erodes in periods where environmental conditions are less adverse. Our results contribute to the current debate on whether and how environmental conditions shape formal and informal institutions.

  10. Justice and Social Cohesion: Some conservative perspectives

    DEFF Research Database (Denmark)

    Pedersen, Søren Hviid

    2011-01-01

    In the wake of recent debates on multiculturalism and value-pluralism, the pressing questions now focuses on whether social cohesion and the notion of justice are sustainable and can be upheld, at least from a European perspective. There are many theoretical and academic responses, mainly from...... liberals, on how to accommodate the different demands of various ethnic and religious groups and at the same time sustain a minimum of social cohesion and justice. One voice is missing and that is a conservative perspective. The purpose of this paper is to formulate a modern conservative analysis...... of this problem. The argument presented in this paper will, first, take its point of departure from David Hume’s notion of sympathy and how this makes social cohesion possible. Second, it will be argued that social cohesion is a prerequisite for the existence of justice, and therefore justice is a derivative...

  11. Cohesion in a Multinational Coalition Center

    National Research Council Canada - National Science Library

    Schaab, Brooke

    2007-01-01

    .... All of the remaining nine items fell within the agree-to-strongly agree area. On interpersonal cohesion, highest agreement was found on items addressing the importance of liking and socializing with team members...

  12. Social cohesion and integration: Learning active citizenship

    NARCIS (Netherlands)

    Jansen, T.J.M.; Chioncel, N.E.; Dekkers, H.P.J.M.

    2006-01-01

    This article starts from a conceptual clarification of the notions social integration and social cohesion as a prerequisite for the reorientation of citizenship education. Turning away from uncritically reproduced assumptions represented in mainstream `deficiency discourse', the article first

  13. Emerging technologies, innovative teachers and moral cohesion

    CSIR Research Space (South Africa)

    Batchelor, J

    2012-05-01

    Full Text Available efficacy when they engage with emerging technologies. The concept of moral cohesion is further expanded and forms the main focus of this article. Keywords: emerging technologies, innovative teachers, moral cohesion, pedagogies, ethics, teacher.... African Renaissance and teacher disposition is identified as the strongest drivers. Teacher training forms the link between the strong drivers and the outcomes manifest as Stewardship and ethical considerations. 3.2 Professional Burden The theme...

  14. Investigating Some Technical Issues on Cohesive Zone Modeling of Fracture

    Science.gov (United States)

    Wang, John T.

    2011-01-01

    This study investigates some technical issues related to the use of cohesive zone models (CZMs) in modeling fracture processes. These issues include: why cohesive laws of different shapes can produce similar fracture predictions; under what conditions CZM predictions have a high degree of agreement with linear elastic fracture mechanics (LEFM) analysis results; when the shape of cohesive laws becomes important in the fracture predictions; and why the opening profile along the cohesive zone length needs to be accurately predicted. Two cohesive models were used in this study to address these technical issues. They are the linear softening cohesive model and the Dugdale perfectly plastic cohesive model. Each cohesive model constitutes five cohesive laws of different maximum tractions. All cohesive laws have the same cohesive work rate (CWR) which is defined by the area under the traction-separation curve. The effects of the maximum traction on the cohesive zone length and the critical remote applied stress are investigated for both models. For a CZM to predict a fracture load similar to that obtained by an LEFM analysis, the cohesive zone length needs to be much smaller than the crack length, which reflects the small scale yielding condition requirement for LEFM analysis to be valid. For large-scale cohesive zone cases, the predicted critical remote applied stresses depend on the shape of cohesive models used and can significantly deviate from LEFM results. Furthermore, this study also reveals the importance of accurately predicting the cohesive zone profile in determining the critical remote applied load.

  15. Group cohesion, task performance, and the experimenter expectancy effect.

    NARCIS (Netherlands)

    Hoogstraten, J.; Vorst, H.C.M.

    1978-01-01

    Studied the effects of cohesion on task fulfillment and explored the influence of task fulfillment on the initial level of cohesion. Within 4-person groups of undergraduates, cohesion was manipulated successfully by a triple procedure. The level of cohesion was ascertained directly after the

  16. Rock Expansion Boundary Anti-Permeability Strength and Its Application in the Coal Mine Floor Water Inrush Evaluation%岩石膨胀界限抗渗强度及在底板突水评价中应用

    Institute of Scientific and Technical Information of China (English)

    段宏飞; 姜振泉; 王一栋; 邵明喜; 赵丽娟; 朱前林

    2012-01-01

    在岩石全应力应变伺服渗透试验的基础上,提出了岩石膨胀界限抗渗强度的概念,并在此基础上建立了底板突水评价模型,模型考虑了底板岩层有效隔水层厚度、岩性、岩体完整程度以及膨胀界限抗渗强度并详细分析了各参数的取值,以兖矿集团杨村煤矿17煤及其2702工作面突水评价为例,证实了以膨胀界限抗渗强度为基础的底板突水评价模型在突水评价上具有可行性.%To solve the difficulties in coal mine floor water inrush evaluation, on the basis of the servo-controlled permeability test of rock in the complete stress-strain process, we proposed the concept of rock expansion boundary anti-permeability strength, and established a theoretical evaluation model of floor water inrush. In the model, several factors, such as the floor aquifuge effective thickness, lithology, rock mass integrity, and expansion boundary anti-permeability strength were considered, and the taking values of all factors were described in detail. Taking the No. 17 coal seam and 2702 working face in Yangcun coal mine, Yanzhou mining group as an example, it proves that the evaluation model based on the expansive boundary anti-permeability strength is feasible to evaluate the coal mine floor water inrush.

  17. Strength Characteristics of Reinforced Sandy Soil

    OpenAIRE

    S. N. Bannikov; Mahamed Al Fayez

    2005-01-01

    Laboratory tests on determination of reinforced sandy soil strength characteristics (angle of internal friction, specific cohesive force) have been carried out with the help of a specially designed instrument and proposed methodology. Analysis of the obtained results has revealed that cohesive forces are brought about in reinforced sandy soil and an angle of internal soil friction becomes larger in comparison with non-reinforced soil.

  18. INTANGIBLE ASSETS THROUGH THE COHESION POLICY

    Directory of Open Access Journals (Sweden)

    Popescu (Stingaciu Ana-Maria

    2012-07-01

    Full Text Available INTANGIBLE ASSETS THROUGH THE COHESION POLICY Roth Anne-Marie-Monika West University of Timisoara Faculty of Economics and Business Administration Popescu (Stingaciu Ana-Maria West University of Timisoara Faculty of Economics and Business Administration Intangible assets in general and intellectual capital in particular are important to both society and organizations. It can be a source of competitive advantage for business and stimulate innovation that leads to wealth generation. Technological revolutions, the rise of the knowledge-based economy and the networked society have all led to the same conclusion that intangibles and how they contribute to value creation have to be appreciated so that the appropriate decisions can be made to protect and enhance them. The Cohesion Policy represents the main EU measure to ensure a balanced and sustainable growth in Europe by promoting harmonious development and reducing the regional disparities. The general objective of the paper is to highlight the important role of the Cohesion Policy in the development of intangible assets. The objectives and the instruments of the Cohesion Policy are designed to support programs on regional development, economic change, enhanced competitiveness and territorial cooperation through the European Union, to develop human resources and employability. Keywords: intangible assets, intellectual capital, Cohesion policy, development; JEL Classification: O43, G32, D24, O34

  19. The variability of root cohesion as an influence on shallow landslide susceptibility in the Oregon Coast Range

    Science.gov (United States)

    Schmidt, K.M.; Roering, J.J.; Stock, J.D.; Dietrich, W.E.; Montgomery, D.R.; Schaub, T.

    2001-01-01

    Decades of quantitative measurement indicate that roots can mechanically reinforce shallow soils in forested landscapes. Forests, however, have variations in vegetation species and age which can dominate the local stability of landslide-initiation sites. To assess the influence of this variability on root cohesion we examined scarps of landslides triggered during large storms in February and November of 1996 in the Oregon Coast Range and hand-dug soil pits on stable ground. At 41 sites we estimated the cohesive reinforcement to soil due to roots by determining the tensile strength, species, depth, orientation, relative health, and the density of roots ???1 mm in diameter within a measured soil area. We found that median lateral root cohesion ranges from 6.8-23.2 kPa in industrial forests with significant understory and deciduous vegetation to 25.6-94.3 kPa in natural forests dominated by coniferous vegetation. Lateral root cohesion in clearcuts is uniformly ???10 kPa. Some 100-year-old industrial forests have species compositions, lateral root cohesion, and root diameters that more closely resemble 10-year-old clearcuts than natural forests. As such, the influence of root cohesion variability on landslide susceptibility cannot be determined solely from broad age classifications or extrapolated from the presence of one species of vegetation. Furthermore, the anthropogenic disturbance legacy modifies root cohesion for at least a century and should be considered when comparing contemporary landslide rates from industrial forests with geologic background rates.

  20. Cohesion and Hierarchy in Physically Abusive Families

    Directory of Open Access Journals (Sweden)

    Clarissa De Antoni

    2009-06-01

    Full Text Available This paper investigates cohesion (emotional bonding and hierarchy (powerstructure in families with abuse against their children. Twenty low-incomefamilies participated. Father, mother and child’s perspective of family relations(cohesion and hierarchy were evaluated by the Family System Test(FAST. The relationship between father-child, mother-child, couple, andamong siblings were evaluated at typical and conflictive situations. Resultsshow a significance regarding to cohesion in typical and conflictive situationfor father-child and mother-child dyads in all perspectives (by father, mother,and child. There is no significant differences regarding to hierarchy. Theseresults suggest that the families see the intrafamilial violence as a constant,since they cannot differentiate between both situations.

  1. Anisotropy in cohesive, frictional granular media

    International Nuclear Information System (INIS)

    Luding, Stefan

    2005-01-01

    The modelling of cohesive, frictional granular materials with a discrete particle molecular dynamics is reviewed. From the structure of the quasi-static granular solid, the fabric, stress, and stiffness tensors are determined, including both normal and tangential forces. The influence of the material properties on the flow behaviour is also reported, including relations between the microscopic attractive force and the macroscopic cohesion as well as the dependence of the macroscopic friction on the microscopic contact friction coefficient. Related to the dynamics, the anisotropy of both structure and stress are exponentially approaching the maximum

  2. Mixed Mode cohesive law with interface dilatation

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Goutianos, Stergios

    2014-01-01

    displacements. As the crack faces displace relatively to each other, the roughness asperities ride on top of each other and result in an opening (dilatation) in the normal direction. Furthermore, the interaction of the crack surfaces in the contact zone gives rise to compressive normal stresses and frictional...... shear stresses opposing the crack face displacements. A phenomenological Mixed Mode cohesive zone law, derived from a potential function, is developed to describe the above mentioned fracture behaviour under monotonic opening. The interface dilatation introduces two new lengths. The cohesive law...

  3. Social Isolation and Social Cohesion: The Effects of K-12 Neighborhood and School Segregation on Intergroup Orientations

    Science.gov (United States)

    Braddock, Jomills Henry, II; Gonzalez, Amaryllis Del Carmen

    2010-01-01

    Background/Context: The United States is becoming increasingly racially and ethnically diverse, and increasingly racially isolated across race-ethnic boundaries. Researchers have argued that both diversity and racial isolation serve to undermine the social cohesion needed to bind American citizens to one another and to society at large. Focus of…

  4. Solidarity and Social Cohesion in Late Modernity

    DEFF Research Database (Denmark)

    Juul, Søren

    2010-01-01

    social cohesion. The central theme is that contemporary solidarity is about recognition and a fair distribution of chances for recognition. This ideal may function as a normative standard for critical research and as a guideline for people in their moral struggles. What ultimately needs to be done...

  5. The Corporate Stake in Social Cohesion

    Science.gov (United States)

    Oketch, Moses O.

    2005-01-01

    Corporate Social Responsibility (CSR) is a function that transcends, but includes, making profits, creating jobs, and producing goods and services. The effectiveness with which corporations perform this function determines their contribution (or lack of contribution) to social cohesion. This article therefore presents a discussion of some of the…

  6. Cohesion as interaction in ELF spoken discourse

    Directory of Open Access Journals (Sweden)

    T. Christiansen

    2013-10-01

    Full Text Available Hitherto, most research into cohesion has concentrated on texts (usually written only in standard Native Speaker English – e.g. Halliday and Hasan (1976. By contrast, following on the work in anaphora of such scholars as Reinhart (1983 and Cornish (1999, Christiansen (2011 describes cohesion as an interac­tive process focusing on the link between text cohesion and discourse coherence. Such a consideration of cohesion from the perspective of discourse (i.e. the process of which text is the product -- Widdowson 1984, p. 100 is especially relevant within a lingua franca context as the issue of different variations of ELF and inter-cultural concerns (Guido 2008 add extra dimensions to the complex multi-code interaction. In this case study, six extracts of transcripts (approximately 1000 words each, taken from the VOICE corpus (2011 of conference question and answer sessions (spoken interaction set in multicultural university con­texts are analysed in depth by means of a qualitative method.

  7. Group Cohesion in Experiential Growth Groups

    Science.gov (United States)

    Steen, Sam; Vasserman-Stokes, Elaina; Vannatta, Rachel

    2014-01-01

    This article explores the effect of web-based journaling on changes in group cohesion within experiential growth groups. Master's students were divided into 2 groups. Both used a web-based platform to journal after each session; however, only 1 of the groups was able to read each other's journals. Quantitative data collected before and…

  8. Group Cohesiveness in the Black Panther Party

    Science.gov (United States)

    Calloway, Carolyn R.

    1977-01-01

    This study selects for study the following propositions: 1) similarity among members increased the degree of cohesiveness within the party, 2) group devotion heightened interest in accomplishing group goals and 3) the threat of an external enemy led to interdependence among members and affected both activities and leadership styles. (Author/AM)

  9. Microzonation Analysis of Cohesionless and Cohesive Soil

    Directory of Open Access Journals (Sweden)

    Tan Choy Soon

    2017-01-01

    Full Text Available Urban seismic risk is a continuous worldwide issue, numerous researchers are putting great effort in dealing with how to minimise the level of the threat. The only way to minimise the social and economic consequences caused but the seismic risk is through comprehensive earthquake scenario analysis such as ground response analysis. This paper intends to examine the characteristic of shear wave velocity and peak ground acceleration on cohesionless and cohesiveness soil. In order to examine the characteristic of shear wave velocity and peak ground acceleration on cohesionless and cohesiveness soil, ground response analysis was performed using Nonlinear Earthquake Site Response Analysis (NERA and Equivalent-linear Earthquake Site Response Analysis (EERA. The value of ground acceleration was initially high at bedrock and vanishes during the propagation process. It is thus, the measured acceleration at surface is therefore much lower as compare to at bedrock. Result shows that seismic waves can travel faster in harder soil as compared to softer soil. Cohesive soil contributes more to the shaking amplification than cohesionless soil such as sand and harder soil. This is known as local site effect. The typical example is the Mexico Earthquake that happened in 1985. As conclusion, peak ground acceleration for cohesive soil is higher than in cohesionless soil.

  10. Validation of the Child Sport Cohesion Questionnaire

    Science.gov (United States)

    Martin, Luc J.; Carron, Albert V.; Eys, Mark A.; Loughead, Todd

    2013-01-01

    The purpose of the present study was to test the validity evidence of the Child Sport Cohesion Questionnaire (CSCQ). To accomplish this task, convergent, discriminant, and known-group difference validity were examined, along with factorial validity via confirmatory factor analysis (CFA). Child athletes (N = 290, M[subscript age] = 10.73 plus or…

  11. Toward a Cohesive Theory of Visual Literacy

    Science.gov (United States)

    Avgerinou, Maria D.; Pettersson, Rune

    2011-01-01

    Despite the fact that to date Visual Literacy (VL) scholars have not arrived at a general consensus for a theoretical organization of the VL field, important conceptual investigations have emerged over the past four decades. In this paper we discuss and synthesize those studies. We then present a first attempt toward a cohesive theory of VL. The…

  12. Slow stress relaxation behavior of cohesive powders

    NARCIS (Netherlands)

    Imole, Olukayode Isaiah; Paulick, Maria; Magnanimo, Vanessa; Morgenmeyer, Martin; Ramaioli, Marco; Chavez Montes, Bruno E.; Kwade, Arno; Luding, Stefan

    2016-01-01

    We present uniaxial (oedometric) compression tests on two cohesive industrially relevant granular materials (cocoa and limestone powder). A comprehensive set of experiments is performed using two devices – the FT4 Powder Rheometer and the custom made lambdameter – in order to investigate the

  13. Effective strength of incoming sediments and its implications for plate boundary propagation: Nankai and Costa Rica as type examples of accreting vs. erosive convergent margins

    Science.gov (United States)

    Kopf, Achim

    2013-11-01

    The location of the seaward tip of a subduction thrust controls material transfer at convergent plate margins, and hence global mass balances. At approximately half of those margins, the material of the subducting plate is completely underthrust so that no accretion or even subduction erosion takes place. Along the remaining margins, material is scraped off the subducting plate and added to the upper plate by frontal accretion. We here examine the physical properties of subducting sediments off Costa Rica and Nankai, type examples for an erosional and an accretionary margin, to investigate which parameters control the level where the frontal thrust cuts into the incoming sediment pile. A series of rotary-shear experiments to measure the frictional strength of the various lithologies entering the two subduction zones were carried out. Results include the following findings: (1) At Costa Rica, clay-rich strata at the top of the incoming succession have the lowest strength (μres = 0.19) while underlying calcareous ooze, chalk and diatomite are strong (up to μres = 0.43; μpeak = 0.56). Hence the entire sediment package is underthrust. (2) Off Japan, clay-rich deposits within the lower Shikoku Basin inventory are weakest (μres = 0.13-0.19) and favour the frontal proto-thrust to migrate into one particular horizon between sandy, competent turbidites below and ash-bearing mud above. (3) Taking in situ data and earlier geotechnical testing into account, it is suggested that mineralogical composition rather than pore-pressure defines the position of the frontal thrust, which locates in the weakest, clay mineral-rich (up to 85 wt.%) materials. (4) Smectite, the dominant clay mineral phase at either margin, shows rate strengthening and stable sliding in the frontal 50 km of the subduction thrust (0.0001-0.1 mm/s, 0.5-25 MPa effective normal stress). (5) Progressive illitization of smectite cannot explain seismogenesis, because illite-rich samples also show velocity

  14. Territorial cohesion post - 2013 : To whomsoever it may concern

    NARCIS (Netherlands)

    Faludi, A.K.F.

    2010-01-01

    Conceived as a motion for resolution, the paper considers territorial cohesion now being on the statute book, the Green Paper on Territorial Cohesion, Barca making the case for integrated, place-based strategies, the EU Strategy for the Baltic Sea Region and the future of Cohesion policy. The

  15. Linking Anger Trait with Somatization in Low-Grade College Students: Moderating Roles of Family Cohesion and Adaptability.

    Science.gov (United States)

    Liu, Liang; Liu, Cuilian; Zhao, Xudong

    2017-02-25

    Between 22% and 58% of patients in primary care settings complain of somatic symptoms. Previous research has found that somatization was associated with anger traits and family functions. However, studies that specifically assess the moderating effect of family function in how anger traits become somatic complaints are lacking. This study was designed to examine whether the variances in family cohesion and family adaptability moderated the strength of the relationship between anger traits and somatization. A cross-section design was conducted and 2008 college students were recruited from a comprehensive university in Shanghai. All participants finished questionnaires including Symptom Check List- 90 (SCL-90), State-Trait Anger Expression Inventory 2 (STAXI-2, Chinese version) and Family Adaptability and Cohesion Scale, second edition (FACES II, Chinese Version) to assess their degree of current somatization, anger trait and family function. Hierarchical linear regression analysis (Enter) was conducted respectively for men and women to examine the moderation effect of family cohesion and family adaptability in the association between anger and somatization. Somatic symptoms were significantly linked in the expected directions with depression and anger trait for both genders. Family cohesion and family adaptability were negatively associated with somatic symptoms. For female college students family cohesion was found to moderate the link between anger trait and somatization, but for male college students the moderation effect of family cohesion was marginally significant. The moderating role of family adaptability was significant for neither male nor female after current depressive symptoms were accounted for. Proneness to anger is an independent predictor of somatization. For women, a high level of family cohesion was a protective factor which could reduce the influence of anger trait on somatic symptoms. Without comorbidity of current depression, family

  16. Natural disasters and indicators of social cohesion

    Czech Academy of Sciences Publication Activity Database

    Calo-Blanco, A.; Kovářík, Jaromír; Mengel, F.; Romero, J. G.

    2017-01-01

    Roč. 12, č. 6 (2017), s. 1-13, č. článku e0176885. E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA14-22044S Institutional support: RVO:67985998 Keywords : social cohesion * trust * climate Subject RIV: AH - Economic s OBOR OECD: Applied Economic s, Econometrics Impact factor: 2.806, year: 2016

  17. Whither Elite Cohesion in Mexico: A Comment

    Science.gov (United States)

    1988-11-01

    the problem of elite cohesion, including the mechanisms-- especially the camarilla system--whereby balance and equilibrium, control and cooptation...Generacicnes: Los Protagonistas de Ia Reforma y la Revoluci(n Mexicana, Secretaria de Educacion Pblica, Consejo Nacional de Fomento Educat ivo, Mexico City...loyalty and discipline toward the system as a whole, and especially its apex, the president, and its key institution, the PRI. All this looks different

  18. Brownfield regeneration: Towards strengthening social cohesion?

    Directory of Open Access Journals (Sweden)

    Minić Marta

    2016-01-01

    Full Text Available In broader terms, the paper refers to the topic of brownfield regeneration, as one of the most complex mechanisms for sustainable spatial development. In addition to the fact that brownfield regeneration demands a variety of instruments, such as: tax subsidies, the change of land use ownership, soil remediation, planning regulative amendments, etc., the complexity of brownfield regeneration is primarily seen in a number of stakeholders participating in such a process. Thus, the paper focuses on the social aspect of brownfield regeneration - precisely, on researching the community role and reviewing the possibilities for achieving the 'local' interests in complex developmental processes. The main research hypothesis is that brownfield regeneration positively affects the creation of and strengthening the social cohesion in the areas close to the brownfield site. More precisley, the paper presents the ways towards strenghtening social cohesion in the initial phase of the brownfield regeneration process, as well as the effects of such a process in its operationalisation phase on social cohesion. The thesis is examined by two main parameters: 1 participation of local community, and 2 social costs and benefits of brownfield regeneration versus greenfield investment. The research results are presented in the form of argumentative essay. In fact, the critical overview of arguments for and against the main research hypothesis is provided based on the review of interdisciplinary literature in the domain of brownfield regeneration. Such research organisation ensures the identification and description of the measures needed for strengthening social cohesion, as an utmost goal of this research. The final research contribution is about offering the guidelines for similar methodological approach in urban research.

  19. Social cohesion and interpersonal conflicts in projects

    OpenAIRE

    Ojiako, Udechukwu; Manville, Graham; Zouk, Nadine; Chipulu, Maxwell

    2016-01-01

    One particular area of project management literature that has continued to gain momentum in literature is its social dimension; with a number of scholars emphasising the fact that there is a considerable social dimension to every project activity. Within this context, the authors examine parameters that drive social facets of projects with a particular focus on social cohesion, interpersonal conflicts and national culture. Data from 167 project managers working in Kuwait were collected utilis...

  20. Micromechanical modeling and inverse identification of damage using cohesive approaches

    International Nuclear Information System (INIS)

    Blal, Nawfal

    2013-01-01

    In this study a micromechanical model is proposed for a collection of cohesive zone models embedded between two each elements of a standard cohesive-volumetric finite element method. An equivalent 'matrix-inclusions' composite is proposed as a representation of the cohesive-volumetric discretization. The overall behaviour is obtained using homogenization approaches (Hashin Shtrikman scheme and the P. Ponte Castaneda approach). The derived model deals with elastic, brittle and ductile materials. It is available whatever the triaxiality loading rate and the shape of the cohesive law, and leads to direct relationships between the overall material properties and the local cohesive parameters and the mesh density. First, rigorous bounds on the normal and tangential cohesive stiffnesses are obtained leading to a suitable control of the inherent artificial elastic loss induced by intrinsic cohesive models. Second, theoretical criteria on damageable and ductile cohesive parameters are established (cohesive peak stress, critical separation, cohesive failure energy,... ). These criteria allow a practical calibration of the cohesive zone parameters as function of the overall material properties and the mesh length. The main interest of such calibration is its promising capacity to lead to a mesh-insensitive overall response in surface damage. (author) [fr

  1. Relating Cohesive Zone Model to Linear Elastic Fracture Mechanics

    Science.gov (United States)

    Wang, John T.

    2010-01-01

    The conditions required for a cohesive zone model (CZM) to predict a failure load of a cracked structure similar to that obtained by a linear elastic fracture mechanics (LEFM) analysis are investigated in this paper. This study clarifies why many different phenomenological cohesive laws can produce similar fracture predictions. Analytical results for five cohesive zone models are obtained, using five different cohesive laws that have the same cohesive work rate (CWR-area under the traction-separation curve) but different maximum tractions. The effect of the maximum traction on the predicted cohesive zone length and the remote applied load at fracture is presented. Similar to the small scale yielding condition for an LEFM analysis to be valid. the cohesive zone length also needs to be much smaller than the crack length. This is a necessary condition for a CZM to obtain a fracture prediction equivalent to an LEFM result.

  2. Cohesion-Induced Stabilization in Stick-Slip Dynamics of Weakly Wet, Sheared Granular Fault Gouge

    Science.gov (United States)

    Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; Marone, Chris; Carmeliet, Jan

    2018-03-01

    We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8,000 spherical particles with a polydisperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces between wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with 2 orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior; we show, however, that at low confining stresses, the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.

  3. Effect of clay type on the velocity and run-out distance of cohesive sediment gravity flows

    Science.gov (United States)

    Baker, Megan; Baas, Jaco H.; Malarkey, Jonathan; Kane, Ian

    2016-04-01

    Novel laboratory experiments in a lock-exchange flume filled with natural seawater revealed that sediment gravity flows (SGFs) laden with kaolinite clay (weakly cohesive), bentonite clay (strongly cohesive) and silica flour (non-cohesive) have strongly contrasting flow properties. Knowledge of cohesive clay-laden sediment gravity flows is limited, despite clay being one of the most abundant sediment types on earth and subaqueous SGFs transporting the greatest volumes of sediment on our planet. Cohesive SGFs are particularly complex owing to the dynamic interplay between turbulent and cohesive forces. Cohesive forces allow the formation of clay flocs and gels, which increase the viscosity and shear strength of the flow, and attenuate shear-induced turbulence. The experimental SGFs ranged from dilute turbidity currents to dense debris flows. For each experiment, the run-out distance, head velocity and thickness distribution of the deposit were measured, and the flow properties were recorded using high-resolution video. Increasing the volume concentration of kaolinite and bentonite above 22% and 17%, respectively, reduced both the maximum head velocity and the run-out distances of the SGFs. We infer that increasing the concentration of clay particles enhances the opportunity for the particles to collide and flocculate, thus increasing the viscosity and shear strength of the flows at the expense of turbulence, and reducing their forward momentum. Increasing the volume concentration in the silica-flour laden flows from 1% to 46% increased the maximum head velocity, owing to the gradual increase in excess density. Thereafter, however, intergranular friction is inferred to have attenuated the turbulence, causing a rapid reduction in the maximum head velocity and run-out distance as suspended sediment concentration was increased. Moving from flows carrying bentonite via kaolinite to silica flour, a progressively larger volumetric suspended sediment concentration was needed

  4. Residual strength evaluation of concrete structural components ...

    Indian Academy of Sciences (India)

    This paper presents methodologies for residual strength evaluation of concrete structural components using linear elastic and nonlinear fracture mechanics principles. The effect of cohesive forces due to aggregate bridging has been represented mathematically by employing tension softening models. Various tension ...

  5. Written cohesion in children with and without language learning disabilities.

    Science.gov (United States)

    Koutsoftas, Anthony D; Petersen, Victoria

    2017-09-01

    Cohesion refers to the linguistic elements of discourse that contribute to its continuity and is an important element to consider as part of written language intervention, especially in children with language learning disabilities (LLD). There is substantial evidence that children with LLD perform more poorly than typically developing (TD) peers on measures of cohesion in spoken language and on written transcription measures; however, there is far less research comparing groups on cohesion as a measure of written language across genres. The current study addresses this gap through the following two aims. First, to describe and compare cohesion in narrative and expository writing samples of children with and without language learning disabilities. Second, to relate measures of cohesion to written transcription and translation measures, oral language, and writing quality. Fifty intermediate-grade children produced one narrative and one expository writing sample from which measures of written cohesion were obtained. These included the frequency, adequacy and complexity of referential and conjunctive ties. Expository samples resulted in more complex cohesive ties and children with TD used more complex ties than peers with LLD. Different relationships among cohesion measures and writing were observed for narrative verse expository samples. Findings from this study demonstrate cohesion as a discourse-level measure of written transcription and how the use of cohesion can vary by genre and group (LLD, TD). Clinical implications for assessment, intervention, and future research are provided. © 2016 Royal College of Speech and Language Therapists.

  6. Finite element analysis of an atomistically derived cohesive model for brittle fracture

    International Nuclear Information System (INIS)

    Lloyd, J T; McDowell, D L; Zimmerman, J A; Jones, R E; Zhou, X W

    2011-01-01

    In order to apply information from molecular dynamics (MD) simulations in problems governed by engineering length and time scales, a coarse graining methodology must be used. In previous work by Zhou et al (2009 Acta Mater. 57 4671–86), a traction-separation cohesive model was developed using results from MD simulations with atomistic-to-continuum measures of stress and displacement. Here, we implement this cohesive model within a combined finite element/cohesive surface element framework (referred to as a finite element approach or FEA), and examine the ability for the atomistically informed FEA to directly reproduce results from MD. We find that FEA shows close agreement of both stress and crack opening displacement profiles at the cohesive interface, although some differences do exist that can be attributed to the stochastic nature of finite temperature MD. The FEA methodology is then used to study slower loading rates that are computationally expensive for MD. We find that the crack growth process initially exhibits a rate-independent relationship between crack length and boundary displacement, followed by a rate-dependent regime where, at a given amount of boundary displacement, a lower applied strain rate produces a longer crack length. Our method is also extended to larger length scales by simulating a compact tension fracture-mechanics specimen with sub-micrometer dimensions. Such a simulation shows a computational speedup of approximately four orders of magnitude over conventional atomistic simulation, while exhibiting the expected fracture-mechanics response. Finally, differences between FEA and MD are explored with respect to ensemble and temperature effects in MD, and their impact on the cohesive model and crack growth behavior. These results enable us to make several recommendations to improve the methodology used to derive cohesive laws from MD simulations. In light of this work, which has critical implications for efforts to derive continuum laws

  7. Effects of spatial variation in cohesion over the concrete-rock interface on dam sliding stability

    Directory of Open Access Journals (Sweden)

    Alexandra Krounis

    2015-12-01

    Full Text Available The limit equilibrium method (LEM is widely used for sliding stability evaluation of concrete gravity dams. Failure is then commonly assumed to occur along the entire sliding surface simultaneously. However, the brittle behaviour of bonded concrete-rock contacts, in combination with the varying stress over the interface, implies that the failure of bonded dam-foundation interfaces occurs progressively. In addition, the spatial variation in cohesion may introduce weak spots where failure can be initiated. Nonetheless, the combined effect of brittle failure and spatial variation in cohesion on the overall shear strength of the interface has not been studied previously. In this paper, numerical analyses are used to investigate the effect of brittle failure in combination with spatial variation in cohesion that is taken into account by random fields with different correlation lengths. The study concludes that a possible existence of weak spots along the interface has to be considered since it significantly reduces the overall shear strength of the interface, and implications for doing so are discussed.

  8. Groupthink: one peril of group cohesiveness.

    Science.gov (United States)

    Rosenblum, E H

    1982-04-01

    A group's aim is to make well-conceived, well-understood, well-accepted and realistic decisions to reach their agreed-upon goals. This aim applies equally to their own goals and those occasionally imposed by outsiders such as hospital administration, accreditation committees and the federal government. Effective groupwork requires group cohesion with its components of trust, risk taking, mutual support, and group esteem. With constant vigilance the group can maintain its positive dynamics, so that the unhealthy state of groupthink does not undermine its existence.

  9. Coaches' Perceptions of Team Cohesion in Paralympic Sports.

    Science.gov (United States)

    Falcão, William R; Bloom, Gordon A; Loughead, Todd M

    2015-07-01

    The purpose of this study was to investigate Paralympic coaches' perceptions of team cohesion. Seven head coaches of summer and winter Canadian Paralympic sport teams participated in the study. Four participants coached individual sports and 3 coached team sports. Data were collected using semistructured interviews and analyzed using thematic analysis. The results addressed the coaches' perceptions of cohesion in the Paralympic sport setting and strategies used to foster cohesion with their teams. Participants described using techniques and strategies for enhancing cohesion that were similar to those in nondisability sport, such as task-related activities, goal setting, and regularly communicating with their athletes. They also listed how cohesion was distinct to the Paralympic setting, such as the importance of interpersonal activities to build social cohesion. The implications of these results for coaching athletes with a disability are also presented.

  10. The association between status and cohesion in sport teams.

    Science.gov (United States)

    Jacob, C S; Carron, A V

    1998-02-01

    The main objective of this study was to establish the relationship between perceptions of status attributes and cohesion and status ranking and cohesion. A secondary aim was to determine whether age (operationalized by scholastic levels) or culture serves as a moderator in the relationship between either status attributes or status ranking and cohesion. Another secondary aim was to determine if differences are present in the importance attached by athletes to status attributes. Canadian and Indian athletes were tested. Although perceptions of the importance of status attributes and cohesiveness were related, the effect size was small (Green, 1991); perceptions of status ranking and cohesiveness were not related. Neither scholastic level nor culture served as a moderator in the association between either status attributes or status rank and cohesion. The importance that athletes attach to status attributes is similar between scholastic levels and across cultures. The results are discussed in terms of the role of status in sport teams.

  11. Quantifying intermolecular interactions of ionic liquids using cohesive energy densities

    Science.gov (United States)

    2017-01-01

    For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced, is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, cedIP, where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, cedC+A, where the ionic vapour constituents are isolated ions. A cedIP dataset is presented for 64 ILs. For the first time an experimental cedC+A, a measure of the strength of the total intermolecular interaction for an IL, is presented. cedC+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between cedIP and the inverse of the molecular volume. A good linear correlation is found between IL cedIP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to cedIP. These findings show that cedIP is very important for understanding IL intermolecular interactions, in spite of cedIP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined. PMID:29308254

  12. Quantifying intermolecular interactions of ionic liquids using cohesive energy densities.

    Science.gov (United States)

    Lovelock, Kevin R J

    2017-12-01

    For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced , is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, ced IP , where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, ced C+A , where the ionic vapour constituents are isolated ions. A ced IP dataset is presented for 64 ILs. For the first time an experimental ced C+A , a measure of the strength of the total intermolecular interaction for an IL, is presented. ced C+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between ced IP and the inverse of the molecular volume. A good linear correlation is found between IL ced IP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to ced IP . These findings show that ced IP is very important for understanding IL intermolecular interactions, in spite of ced IP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined.

  13. 3D Bearing Capacity of Structured Cells Supported on Cohesive Soil: Simplified Analysis Method

    Directory of Open Access Journals (Sweden)

    Martínez-Galván Sergio Antonio

    2013-06-01

    Full Text Available In this paper a simplified analysis method to compute the bearing capacity of structured cell foundations subjected to vertical loading and supported in soft cohesive soil is proposed. A structured cell is comprised by a top concrete slab structurally connected to concrete external walls that enclose the natural soil. Contrary to a box foundation it does not include a bottom slab and hence, the soil within the walls becomes an important component of the structured cell. This simplified method considers the three-dimensional geometry of the cell, the undrained shear strength of cohesive soils and the existence of structural continuity between the top concrete slab and the surrounding walls, along the walls themselves and the walls structural joints. The method was developed from results of numerical-parametric analyses, from which it was found that structured cells fail according to a punching-type mechanism.

  14. Cohesive Laws and Progressive Damage Analysis of Composite Bonded Joints, a Combined Numerical/Experimental Approach

    Science.gov (United States)

    Girolamo, Donato; Davila, Carlos G.; Leone, Frank A.; Lin, Shih-Yung

    2015-01-01

    The results of an experimental/numerical campaign aimed to develop progressive damage analysis (PDA) tools for predicting the strength of a composite bonded joint under tensile loads are presented. The PDA is based on continuum damage mechanics (CDM) to account for intralaminar damage, and cohesive laws to account for interlaminar and adhesive damage. The adhesive response is characterized using standard fracture specimens and digital image correlation (DIC). The displacement fields measured by DIC are used to calculate the J-integrals, from which the associated cohesive laws of the structural adhesive can be derived. A finite element model of a sandwich conventional splice joint (CSJ) under tensile loads was developed. The simulations, in agreement with experimental tests, indicate that the model is capable of predicting the interactions of damage modes that lead to the failure of the joint.

  15. Cohesion, Cracking, Dilation, and Flow -- Rheological Behavior of Cohesive Pharmaceutical Powders

    Science.gov (United States)

    Muzzio, Fernando

    2007-03-01

    Cohesive powders can be loosely defined as systems where the attractive forced between particles exceed the average particle weight. Cohesive powder flow is interesting from a wide range of reasons. Their main characteristic, intermittence, is evidenced both in the interruption of flow out of hoppers (a mundane issue causing great annoyance to industrial practitioners) and in the sudden avalanching of snow and dirt that has terrified and terrified mankind since the dawn of time. At the present time, our ability to predict either of these phenomena (and many more involving cohesive powders) is very limited, primarily due to an incomplete understanding of their constitutive behavior. To wit, consider just a simple fact: a flowing powder never has constant density. Equations describing the relationship between velocity, shear, stress, and density are rudimentary at best. Computational and experimental approaches for characterizing flow behavior are in their infancy. In this talk, I will describe some recent progress achieved at Rutgers by our group. New instruments have been developed to determine simultaneously powder density and cohesive flow effects. Extensive measurements have been carried out focusing on pharmaceutical blends. These results have been used to fine-tune computational models that accurately predict dilation, flow in drums, and flow in hoppers. Impact of these observations for pharmaceutical manufacturing applications will be discussed in some detail.

  16. Personality in teams: its relationship to social cohesion, task cohesion, and team performance

    NARCIS (Netherlands)

    van Vianen, A.E.M.; de Dreu, C.K.W.

    2001-01-01

    This study continued past research on the relationship between personality composition in teams and social cohesion and team performance (Barrick, Stewart, Neubert, & Mount, 1998). Results from the Barrick et al. sample (N = 50) were compared with data from two new samples, one comprising drilling

  17. Environmental cohesion across the Hungarian-Croatian border

    OpenAIRE

    Varjú Viktor

    2016-01-01

    Environmental cohesion (as a new EU paradigm for a place-based interpretation of environmental justice) has a clear connection to territorial cohesion. Based on this idea, advantages for people can include an equitable distribution of environmental protection and access to environmental services. In non-EU countries regional environmental cohesion is used as an instrument to accelerate accession to the EU and it may be manifested as a declaration of environ...

  18. Automated Behavior and Cohesion Assessment Tools, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — An important consideration of long duration space flight operations is interpersonal dynamics that effect crew cohesion and performance. Flight surgeons have stated...

  19. EXAMINATION OF HANDBALL PLAYERS’ TEAM COHESION

    Directory of Open Access Journals (Sweden)

    İlyas Görgüt

    2017-04-01

    Full Text Available The aim of this study was to determine team cohesion of handballplayers who were actively engaged in sport in various categories. The study group consisted of a total of 607 handball players, 317 female and 290 male, selected by random method and from 11 provinces of Turkey according to the some factors. When we examine the age distributions of the participants, 121 athletes appear to be 13 years and under, 309 athletes 14-18 years, 94 athletes 19-23 years, 54 athletes 24-28 years and 29 athletes 29 years and over. In addition, 186 of them expressed their education situation as middle school, 253 of them expressed their education situation as high school and 168 of them expressed their education situation as university. Personal information form and team cohesion scale, developed by Widmeyer et al. (1985 and adapted to Turkish by Moralı (1994, were used as a data collecting tools. The Kolmogorov Smirnov test was used to measure whether the obtained data showed normal distribution or not and nonparametric tests were used to determine the subscale scores because they didn’t show normal disturbance. For binary comparisons Mann Whitney U test, for multiple comparisons Kruskal Wallis variance and for the difference between significant groups Bonferroni Mann Whitney U test were used. As a result of the research, there were significant differences in scale subscale scores in terms of gender, age, educational status, sports experience, income and province variables of handball players.

  20. Cohesion and device reliability in organic bulk heterojunction photovoltaic cells

    KAUST Repository

    Brand, Vitali; Bruner, Christopher; Dauskardt, Reinhold H.

    2012-01-01

    that the phase separated bulk heterojunction layer is the weakest layer and report quantitative cohesion values which ranged from ∼1 to 20 J m -2. The effects of layer thickness, composition, and annealing treatments on layer cohesion are investigated. Using

  1. Packing and Cohesive Properties of Some Locally Extracted Starches

    African Journals Online (AJOL)

    ... properties of the particles affect the packing and cohesive properties of the starches, and are important in predicting the behaviour of the starches during handling and use in pharmaceutical preparations. These properties need to be closely controlled in pre-formulation studies. Keywords: Packing and cohesive properties, ...

  2. A Reappraisal of Lexical Cohesion in Conversational Discourse

    Science.gov (United States)

    Gomez Gonzalez, Maria De Los Angeles

    2013-01-01

    Cohesion, or the connectedness of discourse, has been recognized as playing a crucial role in both language production and comprehension processes. Researchers have debated about the "right" number and classification of cohesive devices, as well as about their interaction with coherence and/or genre. The present study proposes an integrative model…

  3. Cohesion in Online Student Teams versus Traditional Teams

    Science.gov (United States)

    Hansen, David E.

    2016-01-01

    Researchers have found that the electronic methods in use for online team communication today increase communication quality in project-based work situations. Because communication quality is known to influence group cohesion, the present research examined whether online student project teams are more cohesive than traditional teams. We tested…

  4. Understanding Social Cohesion Differences in Common Interest Housing Developments

    NARCIS (Netherlands)

    Dam, van R.I.; Eshuis, J.; Twist, van M.J.W.; Anquetil, V.

    2014-01-01

    The worldwide upsurge of common interest housing developments (CIDs) has stirred up debates regarding community development and social cohesion. Critics have argued that CIDs lack social cohesion because people regulate the community via rules and contracts rather than through social relationships

  5. Anaphoric Referencing: A Cohesive Device in Written and Spoken ...

    African Journals Online (AJOL)

    unique firstlady

    cohesive function "if and when they can be interpreted through their relation to some other (explicit) encoding device in the same passage". ... is Anaphoric but when the implicit term precedes its linguistic referent, the cohesive tie is known as ...

  6. Cohesion: An Overview for the Teacher of Reading. Revised.

    Science.gov (United States)

    Chapman, L. John

    Pronouns, substitutes, elipses, conjunctions, synonyms, antonyms, superordinates and subordinates, and part-whole relations all provide cohesive ties that help a reader understand text. A study at Britain's Open University (England) has revealed the way in which the perception of cohesive ties is achieved as children's reading ability grows.…

  7. Characterizing delamination of fibre composites by mixed mode cohesive laws

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Jacobsen, Torben K.

    2009-01-01

    A novel method is used for the determination of mixed mode cohesive laws and bridging laws for the characterisation of crack bridging in composites. The approach is based on an application of the J integral. The obtained cohesive laws were found to possess high peak stress values. Mixed mode...

  8. Food education: health and social cohesion

    Directory of Open Access Journals (Sweden)

    Eva Zafra Aparici

    2017-07-01

    Full Text Available Using a theoretical-reflexive approach, this article connects the results of various qualitative studies in social conflict and medical anthropology, in order to investigate how food can be a tool for social transformation in terms of health but also in terms of the dialogue, respect and coexistence among people, groups and communities. In this sense the article presents a first approximation to a new theoretical and methodological approach to food education. In this approach, food adopts a political, sociocultural and participatory perspective that brings us closer to an innovative understanding of the phenomenon of food: not only as an analytic and diagnostic tool, but also as an instrument for health education interventions toward conflict resolution and the promotion of healthier societies overall – nutritionally, but also in terms of equality and social cohesion.

  9. Time dependent fracture and cohesive zones

    Science.gov (United States)

    Knauss, W. G.

    1993-01-01

    This presentation is concerned with the fracture response of materials which develop cohesive or bridging zones at crack tips. Of special interest are concerns regarding crack stability as a function of the law which governs the interrelation between the displacement(s) or strain across these zones and the corresponding holding tractions. It is found that for some materials unstable crack growth can occur, even before the crack tip has experienced a critical COD or strain across the crack, while for others a critical COD will guarantee the onset of fracture. Also shown are results for a rate dependent nonlinear material model for the region inside of a craze for exploring time dependent crack propagation of rate sensitive materials.

  10. Cohesive motion in one-dimensional flocking

    International Nuclear Information System (INIS)

    Dossetti, V

    2012-01-01

    A one-dimensional rule-based model for flocking, which combines velocity alignment and long-range centering interactions, is presented and studied. The induced cohesion in the collective motion of the self-propelled agents leads to unique group behavior that contrasts with previous studies. Our results show that the largest cluster of particles, in the condensed states, develops a mean velocity slower than the preferred one in the absence of noise. For strong noise, the system also develops a non-vanishing mean velocity, alternating its direction of motion stochastically. This allows us to address the directional switching phenomenon. The effects of different sources of stochasticity on the system are also discussed. (paper)

  11. In situ erosion of cohesive sediment

    International Nuclear Information System (INIS)

    Williamson, H.J.; Ockenden, M.C.

    1993-01-01

    There has been increasing interest in tidal power schemes and the effect of a tidal energy barrage on the environment. A large man-made environmental change, such as a barrage, would be expected to have significant effects on the sediment distribution and stability of an estuary and these effects need to be assessed when considering a tidal barrage project. This report describes the development of apparatus for in-situ measurements of cohesive sediment erosion on inter-tidal mudflats. Development of the prototype field erosion bell and field testing was commissioned on behalf of the Department of Trade and Industry by the Energy Technology Support Unit (ETSU). This later work commenced in August 1991 and was completed in September 1992. (Author)

  12. Cohesive zone model for direct silicon wafer bonding

    Science.gov (United States)

    Kubair, D. V.; Spearing, S. M.

    2007-05-01

    Direct silicon wafer bonding and decohesion are simulated using a spectral scheme in conjunction with a rate-dependent cohesive model. The cohesive model is derived assuming the presence of a thin continuum liquid layer at the interface. Cohesive tractions due to the presence of a liquid meniscus always tend to reduce the separation distance between the wafers, thereby opposing debonding, while assisting the bonding process. In the absence of the rate-dependence effects the energy needed to bond a pair of wafers is equal to that needed to separate them. When rate-dependence is considered in the cohesive law, the experimentally observed asymmetry in the energetics can be explained. The derived cohesive model has the potential to form a bridge between experiments and a multiscale-modelling approach to understand the mechanics of wafer bonding.

  13. Liquid distribution and cohesion in wet granular assemblies beyond the capillary bridge regime

    International Nuclear Information System (INIS)

    Scheel, M; Seemann, R; Brinkmann, M; Herminghaus, S; Di Michiel, M; Sheppard, A

    2008-01-01

    Dry sand turns into a stiff and moldable material as soon as it is mixed with some liquid. This is a direct consequence of the internal liquid-air interfaces spanning between the grains which causes capillary cohesion by virtue of the surface tension of the liquid. As a model for wet granulates we investigated random packings of submillimeter spherical beads mixed with water. Measurements of the tensile strength and the fluidization threshold demonstrate that the mechanical stiffness is rather insensitive to the liquid content over a wide range. Only for a high liquid content, when more than half of the available pore space is filled with liquid, does the capillary cohesion weaken. In order to understand the interplay between the mechanical properties and the liquid content, we investigated the liquid distribution in random packings of glass spheres by means of x-ray microtomography. The three-dimensional images reveal that the liquid forms a network of capillary bridges fused at local triangular bead configurations. The spontaneous organization of the liquid into these ramified structures, which exhibit a large liquid-air interface, is responsible for the constancy of the cohesive forces in a wide range of liquid contents beyond the onset of capillary bridge coalescence.

  14. Emerging boundaries

    DEFF Research Database (Denmark)

    Løvschal, Mette

    2014-01-01

    of temporal and material variables have been applied as a means of exploring the processes leading to their socioconceptual anchorage. The outcome of this analysis is a series of interrelated, generative boundary principles, including boundaries as markers, articulations, process-related devices, and fixation...

  15. Changing Boundaries

    DEFF Research Database (Denmark)

    Brodkin, Evelyn; Larsen, Flemming

    2013-01-01

    project that is altering the boundary between the democratic welfare state and the market economy. We see workfare policies as boundary-changing with potentially profound implications both for individuals disadvantaged by market arrangements and for societies seeking to grapple with the increasing...

  16. Negotiating boundaries

    DEFF Research Database (Denmark)

    Aarhus, Rikke; Ballegaard, Stinne Aaløkke

    2010-01-01

    to maintain the order of the home when managing disease and adopting new healthcare technology. In our analysis we relate this boundary work to two continuums of visibility-invisibility and integration-segmentation in disease management. We explore five factors that affect the boundary work: objects......, activities, places, character of disease, and collaboration. Furthermore, the processes are explored of how boundary objects move between social worlds pushing and shaping boundaries. From this we discuss design implications for future healthcare technologies for the home.......To move treatment successfully from the hospital to that of technology assisted self-care at home, it is vital in the design of such technologies to understand the setting in which the health IT should be used. Based on qualitative studies we find that people engage in elaborate boundary work...

  17. The role of SEA in integrating and balancing high policy objectives in European cohesion funding programmes

    International Nuclear Information System (INIS)

    Jiricka, Alexandra; Pröbstl, Ulrike

    2013-01-01

    Funding programmes for European cohesion policy are a crucial tool to support the sustainability goals of the European Union and national policies of its member states. All these funding programmes require a Strategic Environmental Assessment (SEA) to enhance sustainable development. This article compares five first SEA applications at cohesion policy level to discuss challenges, limitations and benefits of this instrument. In order to support the SEA-process a “Handbook on SEA for Cohesion Policy 2007–13” (GRDP 2006) was developed. The paper examines the special requirements and challenges at the programme level given the special conditions for stakeholder involvement, integration of SEA in the programme development process and strategies to cope with uncertainties to ensure real compatibility with policy goals. Using action research and in-depth interviews with SEA planners and programme managers enabled us to analyse the suitability of the methodology proposed by the handbook. The results show that some recommendations of the handbook should be changed in order to increase the transparency and to enhance the standard and comparability of the SEA-documents. Overall the SEA proved to be a rather successful tool for the integration of sustainability goals at the EU and national policy levels. Its particular strengths emerged as the process makes uncertainties visible and leads to possible redefinitions while maintaining actual policy goals. - Highlights: ► Comparing five case studies of first applications of SEA at cohesion policy level. ► Overall the SEA proved to be a rather successful tool for the integration of sustainability goals. ► The study makes uncertainties visible and shows how SEA could lead to possible redefinitions.

  18. Pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

    Science.gov (United States)

    Straub, Timothy D.; Over, Thomas M.

    2010-01-01

    This report presents the results of testing the Scour Rate In Cohesive Soils-Erosion Function Apparatus (SRICOS-EFA) method for estimating scour depth of cohesive soils at 15 bridges in Illinois. The SRICOS-EFA method for complex pier and contraction scour in cohesive soils has two primary components. The first component includes the calculation of the maximum contraction and pier scour (Zmax). The second component is an integrated approach that considers a time factor, soil properties, and continued interaction between the contraction and pier scour (SRICOS runs). The SRICOS-EFA results were compared to scour prediction results for non-cohesive soils based on Hydraulic Engineering Circular No. 18 (HEC-18). On average, the HEC-18 method predicted higher scour depths than the SRICOS-EFA method. A reduction factor was determined for each HEC-18 result to make it match the maximum of three types of SRICOS run results. The unconfined compressive strength (Qu) for the soil was then matched with the reduction factor and the results were ranked in order of increasing Qu. Reduction factors were then grouped by Qu and applied to each bridge site and soil. These results, and comparison with the SRICOS Zmax calculation, show that less than half of the reduction-factor method values were the lowest estimate of scour; whereas, the Zmax method values were the lowest estimate for over half. A tiered approach to predicting pier and contraction scour was developed. There are four levels to this approach numbered in order of complexity, with the fourth level being a full SRICOS-EFA analysis. Levels 1 and 2 involve the reduction factors and Zmax calculation, and can be completed without EFA data. Level 3 requires some surrogate EFA data. Levels 3 and 4 require streamflow for input into SRICOS. Estimation techniques for both EFA surrogate data and streamflow data were developed.

  19. Perceived Family Cohesion Moderates Environmental Influences on Prosocial Behavior in Nigerian Adolescent Twins.

    Science.gov (United States)

    Hur, Yoon-Mi; Taylor, Jeanette; Jeong, Hoe-Uk; Park, Min-Seo; Haberstick, Brett C

    2017-06-01

    Research shows that perceived family cohesion is positively related to prosocial behavior in adolescents. In this study, we investigated heritability of prosocial behavior (PB) and perceived family cohesion (FC) among Nigerian twins attending public schools in Lagos State, Nigeria (mean age = 14.7 years, SD = 1.7 years), and explored the issue of whether children's perception of cohesive family environment moderated genetic and environmental influences on (PB). The PB scale of the Strengths and Difficulties Questionnaire and the FC scale of the Family Adaptability and Cohesion Evaluation Scale III were completed by 2,376 twins (241 monozygotic (MZ) male, 354 MZ female, 440 dizygotic (DZ) male, 553 DZ female, and 788 opposite-sex DZ twins). A general sex-limitation and the bivariate genotype by environment interaction (G×E) models were applied to the data. The general sex-limitation model showed no significant sex differences, indicating that additive genetic and non-shared environmental influences were, 38% (95% CI = 31, 46) and 62% (95% CI = 54, 69) for PB and 33% (95% CI = 24, 40) and 67% (95% CI = 60, 76) for FC in both sexes. These estimates were similar to those found in Western and Asian twin studies to date. The correlation between PB and FC was 0.36. The best-fitting bivariate G×E model indicated that FC significantly moderated non-shared environmental influence unique to PB (E×E interaction). Specifically, non-shared environmental contributions to PB were highest when FC was lowest, and decreased as the levels of FC increased. However, genetic variances in PB were stable across all levels of FC. These findings suggest that FC reduces individual differences in PB by changing non-shared environmental experiences rather than genetic factors in PB.

  20. Cohesion energetics of carbon allotropes: Quantum Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyeondeok; Kang, Sinabro; Koo, Jahyun; Lee, Hoonkyung; Kwon, Yongkyung, E-mail: ykwon@konkuk.ac.kr [Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Kim, Jeongnim, E-mail: jnkim@ornl.gov [Materials Science and Technology Division and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-03-21

    We have performed quantum Monte Carlo calculations to study the cohesion energetics of carbon allotropes, including sp{sup 3}-bonded diamond, sp{sup 2}-bonded graphene, sp–sp{sup 2} hybridized graphynes, and sp-bonded carbyne. The computed cohesive energies of diamond and graphene are found to be in excellent agreement with the corresponding values determined experimentally for diamond and graphite, respectively, when the zero-point energies, along with the interlayer binding in the case of graphite, are included. We have also found that the cohesive energy of graphyne decreases systematically as the ratio of sp-bonded carbon atoms increases. The cohesive energy of γ-graphyne, the most energetically stable graphyne, turns out to be 6.766(6) eV/atom, which is smaller than that of graphene by 0.698(12) eV/atom. Experimental difficulty in synthesizing graphynes could be explained by their significantly smaller cohesive energies. Finally, we conclude that the cohesive energy of a newly proposed graphyne can be accurately estimated with the carbon–carbon bond energies determined from the cohesive energies of graphene and three different graphynes considered here.

  1. Cohesion Energetics of Carbon Allotropes: Quantum Monte Carlo Study

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyeondeok [Konkuk University, South Korea; Kang, Sinabro [Konkuk University, South Korea; Koo, Jahyun [Konkuk University, South Korea; Lee, Hoonkyung [Konkuk University, South Korea; Kim, Jeongnim [ORNL; Kwon, Yongkyung [Konkuk University, South Korea

    2014-01-01

    We have performed quantum Monte Carlo calculations to study the cohesion energetics of carbon allotropes, including sp3-bonded diamond, sp2-bonded graphene, sp-sp2 hybridized graphynes, and sp-bonded carbyne. The comput- ed cohesive energies of diamond and graphene are found to be in excellent agreement with the corresponding values de- termined experimentally for diamond and graphite, respectively, when the zero-point energies, along with the interlayer binding in the case of graphite, are included. We have also found that the cohesive energy of graphyne decreases system- atically as the ratio of sp-bonded carbon atoms increases. The cohesive energy of -graphyne, the most energetically- stable graphyne, turns out to be 6.766(6) eV/atom, which is smaller than that of graphene by 0.698(12) eV/atom. Experi- mental difficulty in synthesizing graphynes could be explained by their significantly smaller cohesive energies. Finally we conclude that the cohesive energy of a newly-proposed two-dimensional carbon network can be accurately estimated with the carbon-carbon bond energies determined from the cohesive energies of graphene and three different graphynes.

  2. Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

    KAUST Repository

    Bruner, Christopher; Miller, Nichole C.; McGehee, Michael D.; Dauskardt, Reinhold H.

    2013-01-01

    The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

    KAUST Repository

    Bruner, Christopher

    2013-01-17

    The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Relationship between group cohesion and anxiety in soccer.

    Science.gov (United States)

    Borrego, Carla Chicau; Cid, Luis; Silva, Carlos

    2012-10-01

    Group cohesion in sport is a widely spread theme today. Research has found cohesion to be influenced by several individual and group components. Among the cognitive variables that relate to cohesion we found competitive anxiety. The purpose of this study was to examine the relation between task cohesion (ATG-T, and GI-T) and competitive state anxiety (A-state), and also if there would be a relation between cohesion and self-confidence. Participants were 366 football players of both genders male and female, aged between 15 to 23 years old, from Portugal's championships. Cohesion was measured using the Portuguese version of the Group Environment Questionnaire, and to assess competitive anxiety, we used the Portuguese version of the Competition State Anxiety Inventory 2. Our results show that female athletes report experiencing more cognitive anxiety and less self-confidence than male athletes. Only cognitive anxiety relates in a significantly negative way with the perception of cohesion (GI-T e ATG-T) in the total number of participants and in male athletes. Relatively to the somatic anxiety, it only relates negatively with the perception of the integration of the group in the total number of participants and in the male gender.

  5. Sonority constraints on onset-rime cohesion: evidence from native and bilingual Filipino readers of English.

    Science.gov (United States)

    Alonzo, Angelo; Taft, Marcus

    2002-01-01

    Research in English suggests that syllables can be analyzed in terms of two subunits-the onset (defined as the initial consonant or consonant cluster) and the rime (the unit formed by the vowel and following consonant/s). This study investigated whether nonnative readers of English, which in the case of the present study were native Filipino speakers, also make use of onset-rime units, particularly when some features of their native language (namely infixation and reduplication) appear to foster no awareness of such units. In two lexical decision experiments, monosyllabic English words were presented, divided in between their first and second consonants (e.g., B LIND), at their onset-rime boundary (e.g., BL IND), or at their antibody boundary (e.g., BLI ND). Results indicated that the processes of infixation and reduplication did not affect the English word processing of native Filipino speakers. Rather, results for both native Filipino and native English speakers suggest that onsets composed of an "s + consonant" sequence (e.g., STAMP) are less cohesive than onsets comprised of a stop-liquid sequence (e.g., BLIND). It was concluded that not only may sonority constraints underlie onset cohesiveness, but that such phonetic properties may also be involved in visual word recognition. Copyright 2002 Elsevier Science (USA).

  6. Characteristics of Non-Cohesive Embankment Failure

    Science.gov (United States)

    Yusof, Z. M.; Wahab, A. K. A.; Ismail, Z.; Amerudin, S.

    2018-04-01

    Embankments are important infrastructure built to provide flood control. They also present risks to property and life due to their potential to fail and cause catastrophic flooding. To mitigate these risks, authorities and regulators need to carefully analyse and inspect dams to identify potential failure modes and protect against them. This paper presents morphology of an embankment study and its sediment behaviour of different grain sizes after the embankment fails. A few experiments were carried out for the embankment size of 1V:3H with different sediment grain sizes; medium and coarser sand. The embankment material used is non-cohesive soil with the embankment height of 0.1 m. The embankment is tested with inflows rate of Q = 0.8 L/s. Experimental results showed the peak discharge for the same inflow rate is affected by the shape of embankment breached. The peak discharge of medium grain size of the embankment is highest, which gave 3.63 L/s in comparison with a coarser embankment. This concludes that the embankment morphology patterns are dissimilar to each other. The flow and dimension of embankment are shown to influence the characteristics of embankment failure.

  7. Yield strength of attached copper film

    International Nuclear Information System (INIS)

    Zhang Yan; Zhang Jian-Min

    2011-01-01

    Variation of stress in attached copper film with an applied strain is measured by X-ray diffraction combined with a four-point bending method. A lower slope of the initial elastic segment of the curve of X-ray measured stress versus applied strain results from incomplete elastic strain transferred from the substrate to the film due to insufficiently strong interface cohesion. So the slope of the initial elastic segment of the X-ray stress (or X-ray strain directly) of the film against the substrate applied strain may be used to measure the film-substrate cohesive strength. The yield strength of the attached copper film is much higher than that of the bulk material and varies linearly with the inverse of the film thickness. (condensed matter: structural, mechanical, and thermal properties)

  8. Boundary Spanning

    DEFF Research Database (Denmark)

    Zølner, Mette

    The paper explores how locals span boundaries between corporate and local levels. The aim is to better comprehend potentialities and challenges when MNCs draws on locals’ culture specific knowledge. The study is based on an in-depth, interpretive case study of boundary spanning by local actors in...... approach with pattern matching is a way to shed light on the tacit local knowledge that organizational actors cannot articulate and that an exclusively inductive research is not likely to unveil....

  9. Ascending Aortic Wall Cohesion: Comparison of Bicuspid and Tricuspid Valves

    Directory of Open Access Journals (Sweden)

    Jaroslav Benedik

    2012-01-01

    Full Text Available Objectives. Bicuspid aortic valve (AV represents the most common form of congenital AV malformation, which is frequently associated with pathologies of the ascending aorta. We compared the mechanical properties of the aortic wall between patients with bicuspid and tricuspid AV using a new custom-made device mimicking transversal aortic wall shear stress. Methods. Between 03/2010 and 07/2011, 190 consecutive patients undergoing open aortic valve replacement at our institution were prospectively enrolled, presenting either with a bicuspid (group 1, n=44 or a tricuspid (group 2, n=146 AV. Aortic wall specimen were examined with the “dissectometer” resulting in nine specific aortic-wall parameters derived from tensile strength curves (TSC. Results. Patients with a bicuspid AV showed significantly more calcified valves (43.2% versus 15.8%, P<0.001, and a significantly thinner aortic wall (2.04±0.42 mm versus 2.24±0.41 mm, P=0.008. Transesophageal echocardiography diameters (annulus, aortic sinuses, and sinotubular junction were significantly larger in the bicuspid group (P=0.003, P=0.02, P=0.01. We found no difference in the aortic wall cohesion between both groups as revealed by shear stress testing (P=0.72, P=0.40, P=0.41. Conclusion. We observed no differences of TSC in patients presenting with tricuspid or bicuspid AVs. These results may allow us to assume that the morphology of the AV and the pathology of the ascending aorta are independent.

  10. Bridge pier scour in cohesive soil: a review

    Indian Academy of Sciences (India)

    Y Sonia Devi

    process and mechanism at bridge pier in cohesive and noncohesive soil are presented. The effects ... examples: one under laboratory condition and another under field condition. ..... not take part in scouring as these sediments are swept over.

  11. Social cohesion: solution or driver of urban violence? | IDRC ...

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

    2016-09-28

    Sep 28, 2016 ... Social cohesion can play an important role in building and maintaining ... Analysis of Violence demonstrates how social bonds and stark inequalities can also play ... Conflict and development in the hill settlements of Guwahati.

  12. Social cohesion: solution or driver of urban violence?

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

    to the state intervention, eroding existing civil society organization. The presence of the police ... creating its own parallel structures to existing representative bodies, ... When designing interventions take into account that social cohesion may ...

  13. Utilization of Large Cohesive Interface Elements for Delamination Simulation

    DEFF Research Database (Denmark)

    Bak, Brian Lau Verndal; Lund, Erik

    2012-01-01

    This paper describes the difficulties of utilizing large interface elements in delamination simulation. Solutions to increase the size of applicable interface elements are described and cover numerical integration of the element and modifications of the cohesive law....

  14. Social cohesion: The missing link in overcoming violence and ...

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

    Researchers will test the hypothesis that social cohesion is a critical factor in ... to community members, and ethnographic social network analysis, to help map ... to identify the most effective strategies for addressing these challenges in Latin ...

  15. Student leadership and advocacy for social cohesion: A South ...

    African Journals Online (AJOL)

    at how social cohesion could benefit economic development, hoped thereby ... institutions pledged to reverse 'outsourcing' to 'insourcing' of cleaning services, there is .... It is not so much the scale of these ills as it is the perceived failure of the.

  16. Effect of softening function on the cohesive crack fracture ...

    Indian Academy of Sciences (India)

    The cohesive crack model with linear softening yields the fracture process zones lower by ..... ignored during numerical simulation. In the crack band ..... performed with developed computer program using MATLAB for the following numerical.

  17. Barossa Night: cohesion in the British Army officer corps.

    Science.gov (United States)

    Bury, Patrick

    2017-06-01

    Contrasting the classical explanation of military group cohesion as sustained by interpersonal bonds, recent scholars have highlighted the importance of ritualized communication, training and drills in explaining effective military performance in professional armies. While this has offered a welcome addition to the cohesion literature and a novel micro-sociological method of examining cohesion, its primary evidential base has been combat groups. Indeed, despite their prominent role in directing operations over the past decade, the British Army's officer corps has received relatively little attention from sociologists during this period. No attempt has been made to explain cohesion in the officer corps. Using a similar method to recent cohesion scholars, this paper seeks to address this imbalance by undertaking a micro-sociology of one ritual in particular: 'Barossa Night' in the Royal Irish Regiment. Firstly, it draws on the work of Durkheim to examine how cohesion amongst the officer corps is created and sustained through a dense array of practises during formal social rituals. It provides evidence that the use of rituals highlights that social solidarity is central to understanding officer cohesion. Secondly, following Hockey's work on how private soldiers negotiate order, the paper shows how this solidarity in the officer corps is based on a degree of negotiated order and the need to release organizational tensions inherent in a strictly hierarchical rank structure. It highlights how the awarding of gallantry medals can threaten this negotiated order and fuel deviancy. In examining this behaviour, the paper shows that even amongst an officer class traditionally viewed as the elite upholders of organizational discipline, the negotiation of rank and hierarchy can be fluid. How deviant behaviour is later accepted and normalized by senior officers indicates that negotiated order is as important to understanding cohesion in the British Army's officer corps as it is

  18. Substitution as a Device of Grammatical Cohesion in English Contexts

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Hasannejad

    2012-05-01

    Full Text Available The present study set out to investigate the effect of teaching substitution as a kind of grammatical cohesion on the true identification of confusing substitution elements with cohesive or non-cohesive roles in different contexts and also the production of modal, reporting and conditional contexts through clausal substitution acquaintance. To this end, the following procedures were taken. First 120 male and female EFL students were selected from Iranshahr Azad University. Having administered the language proficiency test, researchers selected 80 students as intermediate subjects according to their TOEFL band scores. First, pretests of cohesion identification (substitution and production of modal, reporting and conditional environments were administered to both control and experimental groups. Then, the experimental group was exposed to the teaching of the above-said above-mentioned cohesive device. Finally, post-tests of substitution elements’ identification and modal, reporting and conditional contexts’ production through clausal substitution familiarity were administered. The results showed that cohesive device treatment helped students on the true identification of substitution elements. Another finding proved that EFL students might have no difficulty in learning certain rules or classification of rules and application of their clausal substitution knowledge in creating modal, reporting and conditional contexts. Our findings can have implications for the field of language learning and teaching.

  19. Blurring Boundaries

    DEFF Research Database (Denmark)

    Neergaard, Ulla; Nielsen, Ruth

    2010-01-01

    of welfare functions into EU law both from an internal market law and a constitutional law perspective. The main problem areas covered by the Blurring Boundaries project were studied in sub-projects on: 1) Internal market law and welfare services; 2) Fundamental rights and non-discrimination law aspects......; and 3) Services of general interest. In the Blurring Boundaries project, three aspects of the European Social Model have been particularly highlighted: the constitutionalisation of the European Social Model, its multi-level legal character, and the clash between market access justice at EU level...... and distributive justice at national level....

  20. Britishness and Community Cohesion in Muslim News Online

    Directory of Open Access Journals (Sweden)

    Hassen ZRIBA

    2013-12-01

    Full Text Available The issues of British national identity and social cohesion have become pressing concerns within the multicultural fabric of contemporary British society. The increasing number of immigrants and their offspring, along with the maintenance of their cultural roots, seem to represent a serious defiance to social cohesion and the alleged “purity” of Britishness. A number of race related reports were produced by the official authorities to churn out the necessary steps to be followed by the British (immigrants and host community in order to keep social stability and community cohesion. Thus, the politics of community cohesion came to the fore as the neologism of contemporary British political discourse. Such new discourse of governance has been digested and processed differently by different mass media. It has been decoded, for instance, preferably by mainstream news agencies like BBC News Online. However, arguably, it is read appositionally or at best negotiatedly by ethnicity-related news agencies such as Muslim News Online. In this article, attempt has been made to adopt media discourse analysis tools to decipher the ways Muslim News Online decoded and then encoded the hegemonic official discourses of Britishness and community cohesion. A critical and interpretative approach is used to accomplish such study. The corpus of this study is primarily extracted from the website of the Muslim News Online.

  1. Transport and deposition of cohesive pharmaceutical powders in human airway

    Directory of Open Access Journals (Sweden)

    Wang Yuan

    2017-01-01

    Full Text Available Pharmaceutical powders used in inhalation therapy are in the size range of 1-5 microns and are usually cohesive. Understanding the cohesive behaviour of pharmaceutical powders during their transportation in human airway is significant in optimising aerosol drug delivery and targeting. In this study, the transport and deposition of cohesive pharmaceutical powders in a human airway model is simulated by a well-established numerical model which combines computational fluid dynamics (CFD and discrete element method (DEM. The van der Waals force, as the dominant cohesive force, is simulated and its influence on particle transport and deposition behaviour is discussed. It is observed that even for dilute particle flow, the local particle concentration in the oral to trachea region can be high and particle aggregation happens due to the van der Waals force of attraction. It is concluded that the deposition mechanism for cohesive pharmaceutical powders, on one hand, is dominated by particle inertial impaction, as proven by previous studies; on the other hand, is significantly affected by particle aggregation induced by van der Waals force. To maximum respiratory drug delivery efficiency, efforts should be made to avoid pharmaceutical powder aggregation in human oral-to-trachea airway.

  2. Transport and deposition of cohesive pharmaceutical powders in human airway

    Science.gov (United States)

    Wang, Yuan; Chu, Kaiwei; Yu, Aibing

    2017-06-01

    Pharmaceutical powders used in inhalation therapy are in the size range of 1-5 microns and are usually cohesive. Understanding the cohesive behaviour of pharmaceutical powders during their transportation in human airway is significant in optimising aerosol drug delivery and targeting. In this study, the transport and deposition of cohesive pharmaceutical powders in a human airway model is simulated by a well-established numerical model which combines computational fluid dynamics (CFD) and discrete element method (DEM). The van der Waals force, as the dominant cohesive force, is simulated and its influence on particle transport and deposition behaviour is discussed. It is observed that even for dilute particle flow, the local particle concentration in the oral to trachea region can be high and particle aggregation happens due to the van der Waals force of attraction. It is concluded that the deposition mechanism for cohesive pharmaceutical powders, on one hand, is dominated by particle inertial impaction, as proven by previous studies; on the other hand, is significantly affected by particle aggregation induced by van der Waals force. To maximum respiratory drug delivery efficiency, efforts should be made to avoid pharmaceutical powder aggregation in human oral-to-trachea airway.

  3. Cohesiveness in financial news and its relation to market volatility.

    Science.gov (United States)

    Piškorec, Matija; Antulov-Fantulin, Nino; Novak, Petra Kralj; Mozetič, Igor; Grčar, Miha; Vodenska, Irena; Smuc, Tomislav

    2014-05-22

    Motivated by recent financial crises, significant research efforts have been put into studying contagion effects and herding behaviour in financial markets. Much less has been said regarding the influence of financial news on financial markets. We propose a novel measure of collective behaviour based on financial news on the Web, the News Cohesiveness Index (NCI), and we demonstrate that the index can be used as a financial market volatility indicator. We evaluate the NCI using financial documents from large Web news sources on a daily basis from October 2011 to July 2013 and analyse the interplay between financial markets and finance-related news. We hypothesise that strong cohesion in financial news reflects movements in the financial markets. Our results indicate that cohesiveness in financial news is highly correlated with and driven by volatility in financial markets.

  4. Cohesiveness in Financial News and its Relation to Market Volatility

    Science.gov (United States)

    Piškorec, Matija; Antulov-Fantulin, Nino; Novak, Petra Kralj; Mozetič, Igor; Grčar, Miha; Vodenska, Irena; Šmuc, Tomislav

    2014-01-01

    Motivated by recent financial crises, significant research efforts have been put into studying contagion effects and herding behaviour in financial markets. Much less has been said regarding the influence of financial news on financial markets. We propose a novel measure of collective behaviour based on financial news on the Web, the News Cohesiveness Index (NCI), and we demonstrate that the index can be used as a financial market volatility indicator. We evaluate the NCI using financial documents from large Web news sources on a daily basis from October 2011 to July 2013 and analyse the interplay between financial markets and finance-related news. We hypothesise that strong cohesion in financial news reflects movements in the financial markets. Our results indicate that cohesiveness in financial news is highly correlated with and driven by volatility in financial markets. PMID:24849598

  5. Elongational rheology and cohesive fracture of photo-oxidated LDPE

    Energy Technology Data Exchange (ETDEWEB)

    Rolón-Garrido, Víctor H., E-mail: victor.h.rolongarrido@tu-berlin.de; Wagner, Manfred H. [Chair of Polymer Engineering/Polymer Physics, Berlin Institute of Technology (TU Berlin), Fasanenstrasse 90, D-10623 Berlin (Germany)

    2014-01-15

    It was found recently that low-density polyethylene (LDPE) samples with different degrees of photo-oxidation represent an interesting system to study the transition from ductile to cohesive fracture and the aspects of the cohesive rupture in elongational flow. Sheets of LDPE were subjected to photo-oxidation in the presence of air using a xenon lamp to irradiate the samples for times between 1 day and 6 weeks. Characterisation methods included Fourier transform infrared spectroscopy, solvent extraction method, and rheology in shear and uniaxial extensional flows. Linear viscoelasticity was increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by the carbonyl index, acid and aldehydes groups, and gel fraction. The molecular stress function model was used to quantify the experimental data, and the nonlinear model parameter β was found to be correlated with the gel content. The uniaxial data showed that the transition from ductile to cohesive fracture was shifted to lower elongational rates, the higher the gel content was. From 2 weeks photo-oxidation onwards, cohesive rupture occurred at every strain rate investigated. The true strain and true stress at cohesive fracture as well as the energy density applied to the sample up to fracture were analyzed. At low gel content, rupture was mainly determined by the melt fraction while at high gel content, rupture occurred predominantly in the gel structure. The strain at break was found to be independent of strain rate, contrary to the stress at break and the energy density. Thus, the true strain and not the stress at break or the energy density was found to be the relevant physical quantity to describe cohesive fracture behavior of photo-oxidated LDPE. The equilibrium modulus of the gel structures was correlated with the true strain at rupture. The stiffer the gel structure, the lower was the deformation tolerated before the sample breaks.

  6. Group cohesion in sports teams of different professional level

    Directory of Open Access Journals (Sweden)

    Vazha M. Devishvili

    2017-12-01

    Full Text Available Background. Team sports are not only the most exciting sporting events. but also complex activities that make serious demands on players. The effectiveness of the team depends not only on the high level of gaming interaction. but also on the relationship between the players. The work is based on the material of sports teams and is devoted to the study of the phenomenon of group cohesion. As a basic model. the authors choose a 4-factor model that describes cohesion in sports teams. The paper also considered the phenomenon of the emergence of the aggregate subject in the process of joint activity. when the participants feel themselves as a whole and experience feelings of satisfaction and a surge of energy. Objective. The main objective of the work is to investigate the relationship between the level of team cohesion and subjective feelings of unity of its players. As additional variables in the study there is a sport (football and volleyball and team level (amateur and professional. To test the assumptions. two methods were used (the Sport Team Cohesion Questionnaire and the Subject Unity Index. which allow not only to determine the overall level of cohesion and unity. but also to reveal the structure of both phenomena. The study involved two men’s volleyball and two men’s football teams of different ages: 8-9 years (39 athletes; 12-14 years (24 athletes and 18-25 years (41 athletes. Design. For amateur groups represented by children’s and teenage sports teams. significant correlations between unity and unity were obtained (r = 0.618. p <0.01; r = 0.477. p <0.05. For professional teams. no significant correlations were found. Influence of the sport on cohesion is also different for amateur and professional teams. In the first case. the cohesion is higher for football players (U = 118. p <0.05. and in the second case for volleyball players (U = 124. p <0.05. Results. The findings indicate that the professional level of players affects group

  7. Group cohesion in sports teams of different professional level

    OpenAIRE

    Vazha M. Devishvili; Marina O. Mdivani; Daria S. Elgina

    2017-01-01

    Background. Team sports are not only the most exciting sporting events. but also complex activities that make serious demands on players. The effectiveness of the team depends not only on the high level of gaming interaction. but also on the relationship between the players. The work is based on the material of sports teams and is devoted to the study of the phenomenon of group cohesion. As a basic model. the authors choose a 4-factor model that describes cohesion in sports teams. The pape...

  8. On the application of cohesive crack modeling in cementitious materials

    DEFF Research Database (Denmark)

    Stang, Henrik; Olesen, John Forbes; Poulsen, Peter Noe

    2007-01-01

    typically for multi scale problems such as crack propagation in fiber reinforced composites. Mortar and concrete, however, are multi-scale materials and the question naturally arises, if bridged crack models in fact are more suitable for concrete and mortar as well? In trying to answer this question a model......Cohesive crack models-in particular the Fictitious Crack Model - are applied routinely in the analysis of crack propagation in concrete and mortar. Bridged crack models-where cohesive stresses are assumed to exist together with a stress singularity at the crack tip-on the other hand, are used...

  9. Portraying the Contribution of Individual Behaviors to Team Cohesion and Performance

    Science.gov (United States)

    Parke, Bonny; Orasanu, Judith

    2012-01-01

    Behaviors of individuals in teams both contribute to and are molded by team dynamics. How they do so has been the subject of much research. A method of portraying individuals' behaviors in teams, the Team Diagramming Method (TDM) is presented. Behaviors are rated by other team members on three important dimensions: positivity/negativity, dominant/submissive, and task-orientedness/expressiveness. A study of 5-person teams engaging in a 3-day moon simulation task demonstrated that measures of these perceived behaviors as well as the variances of these behaviors correlated with cohesion measures and performance. The method shows strengths and weaknesses of particular teams and, by comparison with high-performing teams, suggests interventions based on individual as well as team behaviors. The primary goal of this study was to determine the extent to which these team level variables, derived from all team members' rated behaviors, were associated with previous methods of measuring cohesion and with performance. A secondary goal was to determine the stability of TDM measures over time by comparing team level variables based on ratings early and later in the team s work together.

  10. INTERACTIVE EFFECTS OF TEAM COHESION ON PERCEIVED EFFICACY IN SEMI-PROFESSIONAL SPORT

    Directory of Open Access Journals (Sweden)

    Francisco Miguel Leo Marcos

    2010-06-01

    Full Text Available The present study examined the relationships among cohesion, self-efficacy, coaches' perceptions of their players' efficacy at the individual level and athletes' perceptions of their teammates' efficacy. Participants (n = 76 recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and social cohesion. Regression analysis results suggest task cohesion positively related to coaches and teammate´s perception of efficacy. These results have implications for practitioners in terms of the importance of team building to enhance team cohesion and feelings of efficacy

  11. Boundary issues

    Science.gov (United States)

    Townsend, Alan R.; Porder, Stephen

    2011-03-01

    What is our point of no return? Caesar proclaimed 'the die is cast' while crossing the Rubicon, but rarely does modern society find so visible a threshold in our continued degradation of ecosystems and the services they provide. Humans have always used their surroundings to make a living— sometimes successfully, sometimes not (Diamond 2005)—and we intuitively know that there are boundaries to our exploitation. But defining these boundaries has been a challenge since Malthus first prophesied that nature would limit the human population (Malthus 1798). In 2009, Rockström and colleagues tried to quantify what the 6.8 billion (and counting) of us could continue to get away with, and what we couldn't (Rockström et al 2009). In selecting ten 'planetary boundaries', the authors contend that a sustainable human enterprise requires treating a number of environmental thresholds as points of no return. They suggest we breach these Rubicons at our own peril, and that we've already crossed three: biodiversity loss, atmospheric CO2, and disruption of the global nitrogen (N) cycle. As they clearly hoped, the very act of setting targets has provoked scientific inquiry about their accuracy, and about the value of hard targets in the first place (Schlesinger 2009). Such debate is a good thing. Despite recent emphasis on the science of human-ecosystem interactions, understanding of our planetary boundaries is still in its infancy, and controversy can speed scientific progress (Engelhardt and Caplan 1987). A few weeks ago in this journal, Carpenter and Bennett (2011) took aim at one of the more controversial boundaries in the Rockström analysis: that for human alteration of the global phosphorus (P) cycle. Rockström's group chose riverine P export as the key indicator, suggesting that humans should not exceed a value that could trigger widespread marine anoxic events—and asserting that we have not yet crossed this threshold. There are defensible reasons for a marine

  12. boundary dissipation

    Directory of Open Access Journals (Sweden)

    Mehmet Camurdan

    1998-01-01

    are coupled by appropriate trace operators. This overall model differs from those previously studied in the literature in that the elastic chamber floor is here more realistically modeled by a hyperbolic Kirchoff equation, rather than by a parabolic Euler-Bernoulli equation with Kelvin-Voight structural damping, as in past literature. Thus, the hyperbolic/parabolic coupled system of past literature is replaced here by a hyperbolic/hyperbolic coupled model. The main result of this paper is a uniform stabilization of the coupled PDE system by a (physically appealing boundary dissipation.

  13. Cohesive Modeling of Transverse Cracking in Laminates with a Single Layer of Elements per Ply

    Science.gov (United States)

    VanDerMeer, Frans P.; Davila, Carlos G.

    2013-01-01

    This study aims to bridge the gap between classical understanding of transverse cracking in cross-ply laminates and recent computational methods for the modeling of progressive laminate failure. Specifically, the study investigates under what conditions a finite element model with cohesive X-FEM cracks can reproduce the in situ effect for the ply strength. It is shown that it is possible to do so with a single element across the thickness of the ply, provided that the interface stiffness is properly selected. The optimal value for this interface stiffness is derived with an analytical shear lag model. It is also shown that, when the appropriate statistical variation of properties has been applied, models with a single element through the thickness of a ply can predict the density of transverse matrix cracks

  14. Cohesive zone model of carbon nanotube-coated carbon fiber/polyester composites

    International Nuclear Information System (INIS)

    Agnihotri, Prabhat Kamal; Kar, Kamal K; Basu, Sumit

    2012-01-01

    It has been previously reported that the average properties of carbon nanotube-coated carbon fiber/polyester multiscale composites critically depend on the length and density of nanotubes on the fiber surface. In this paper the effect of nanotube length and density on the interfacial properties of the carbon nanotube-coated carbon fiber–polymer interface has been studied using shear lag and a cohesive zone model. The latter model incorporates frictional sliding after complete debonding between the fiber and matrix and has been developed to quantify the effect of nanotube coating on various interfacial characterizing parameters. Our numerical results indicate that fibers with an optimal coverage and length of nanotubes significantly increase the interfacial strength and friction between the fiber and polymer. However, they also embrittle the interface compared with bare fibers. (paper)

  15. Long Fibre Composite Modelling Using Cohesive User's Element

    International Nuclear Information System (INIS)

    Kozak, Vladislav; Chlup, Zdenek

    2010-01-01

    The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.

  16. Coach-Initiated Motivational Climate and Cohesion in Youth Sport

    Science.gov (United States)

    Eys, Mark A.; Jewitt, Eryn; Evans, M. Blair; Wolf, Svenja; Bruner, Mark W.; Loughead, Todd M.

    2013-01-01

    Purpose: The general purpose of the present study was to examine the link between cohesion and motivational climate in youth sport. The first specific objective was to determine if relationships demonstrated in previous research with adult basketball and handball participants would be replicated in a younger sample and with a more heterogeneous…

  17. Examining the Relationship between Emotional Intelligence and Group Cohesion

    Science.gov (United States)

    Moore, Amanda; Mamiseishvili, Ketevan

    2012-01-01

    Collaborative learning experiences increase student learning, but what happens when students fail to collaborate? The authors investigated the relationship between emotional intelligence and group cohesion by studying 44 undergraduate teams who were completing semester-long projects in their business classes at a small private university in the…

  18. Fear, crime, and social cohesion in urban South Africa | IDRC ...

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

    2016-12-13

    Dec 13, 2016 ... Social cohesion” broadly refers to the factors that hold a society ... published in March 2016, explores the role of social cohesion and ... Learn more about IDRC's research support to make cities safer through the Safe and Inclusive Cities partnership with the UK's Department for International Development.

  19. Isotropic compression of cohesive-frictional particles with rolling resistance

    NARCIS (Netherlands)

    Luding, Stefan; Benz, Thomas; Nordal, Steinar

    2010-01-01

    Cohesive-frictional and rough powders are the subject of this study. The behavior under isotropic compression is examined for different material properties involving Coulomb friction, rolling-resistance and contact-adhesion. Under isotropic compression, the density continuously increases according

  20. ReaderBench: An Integrated Cohesion-Centered Framework

    NARCIS (Netherlands)

    Dascalu, Mihai; Stavarache, Lucia Larise; Dessus, Philippe; Trausan-Matu, Stefan; McNamara, Danielle S.; Bianco, Maryse

    2015-01-01

    Dascalu, M., Stavarache, L.L., Dessus, P., Trausan-Matu, S., McNamara, D.S., & Bianco, M. (2015). ReaderBench: An Integrated Cohesion-Centered Framework. In G. Conole, T. Klobucar, C. Rensing, J. Konert & É. Lavoué (Eds.), 10th European Conf. on Technology Enhanced Learning (pp. 505–508). Toledo,

  1. Teacher Governance Factors and Social Cohesion: Insights from Pakistan

    Science.gov (United States)

    Halai, Anjum; Durrani, Naureen

    2016-01-01

    This paper explores teacher governance factors, particularly recruitment and deployment of teachers, in relation to inequalities and social cohesion. Pakistan introduced major reforms in education in the post 9/11 context of escalating conflict. These include a merit and needs-based policy on teacher recruitment to eliminate corruption in…

  2. An enriched cohesive zone model for delamination in brittle interfaces

    NARCIS (Netherlands)

    Samimi, M.; Dommelen, van J.A.W.; Geers, M.G.D.

    2009-01-01

    Application of standard cohesive zone models in a finite element framework to simulate delamination in brittle interfaces may trigger non-smooth load-displacement responses that lead to the failure of iterative solution procedures. This non-smoothness is an artifact of the discretization; and hence

  3. Interfacial stresses in strengthened beam with shear cohesive zone ...

    Indian Academy of Sciences (India)

    The results of parametric study are compared with those of Smith and Teng. They confirm the accuracy of the proposed approach in predicting both interfacial shear and normal stresses. Keywords. Strengthened beam; interfacial stresses; cohesive zone; shear deformation. 1. Introduction. The FRP plates can be either ...

  4. The Impact of Cooperative Video Games on Team Cohesion

    Science.gov (United States)

    Anderson, Greg

    2010-01-01

    In today's economy, productivity and efficiency require collaboration between employees. In order to improve collaboration the factors affecting teamwork must be examined to identify where changes can be made in order to increase performance. One factor contributing to teamwork is team cohesion and represents a process whereby members are joined…

  5. Cohesive zone modelling and the fracture process of structural tape

    DEFF Research Database (Denmark)

    Stigh, Ulf; Biel, Anders; Svensson, Daniel

    2016-01-01

    and the separation is measured experimentally using methods based on the path independence of the J-integral. Repeated experiments are performed at quasi-static loading. A mixed mode cohesive law is adapted to the experimental data. The law is implemented as a UMAT in Abaqus. Simulations show minor thermal...

  6. Explaining Couple Cohesion in Different Types of Gay Families

    Science.gov (United States)

    van Eeden-Moorefield, Brad; Pasley, Kay; Crosbie-Burnett, Margaret; King, Erin

    2012-01-01

    This Internet-based study used data from a convenience sample of 176 gay men in current partnerships to examine differences in outness, cohesion, and relationship quality between three types of gay male couples: first cohabiting partnerships, repartnerships, and gay stepfamilies. Also, we tested whether relationship quality mediated the link…

  7. Meiotic sister chromatid cohesion and recombination in two filamentous fungi

    NARCIS (Netherlands)

    Heemst, van D.

    2000-01-01

    Homologous recombination and sister chromatid cohesion play important roles in the maintenance of genome integrity and the fidelity of chromosome segregation in mitosis and meiosis. Within the living cell, the integrity of the DNA is threatened by various factors that cause DNA-lesions, of

  8. Towards an integrated approach to cohesion and coherence in ...

    African Journals Online (AJOL)

    The notions of cohesion and coherence have a long tradition in the linguistic literature. They date back to ancient .... syntax, and operates in short-term or working memory. Coherence is related to the ..... account of all the elements that occur in the film, namely, words, gestures, images, music and sound effects. In other ...

  9. Visibility and anonymity effects on attraction and group cohesiveness

    NARCIS (Netherlands)

    Lea, Martin; Spears, Russell; Watt, Susan E.

    2007-01-01

    This study investigated attraction and group cohesiveness under different visibility and anonymity conditions for social categories that differed in their capacity to be visually cued. Using computer-mediated communication in 36 mixed gender (visually cued category) and nationality (non-visually

  10. Facilitating or hindering social cohesion? The impact of the ...

    African Journals Online (AJOL)

    However, we show in this article that that the impact of the CWP is not always positive and that the CWP may in some cases result in tensions and contradictions that hinder social cohesion and even cause violence. If not implemented in a consultative participatory manner, the CWP may be a source of conflict rather than of ...

  11. Working with Group-Tasks and Group Cohesiveness

    Science.gov (United States)

    Anwar, Khoirul

    2016-01-01

    This study aimed at exploring the connection between the use of group task and group cohesiveness. This study is very important because the nature of the learner's success is largely determined by the values of cooperation, interaction, and understanding of the learning objectives together. Subjects of this study are 28 students on the course…

  12. Cohesive Errors in Writing among ESL Pre-Service Teachers

    Science.gov (United States)

    Kwan, Lisa S. L.; Yunus, Melor Md

    2014-01-01

    Writing is a complex skill and one of the most difficult to master. A teacher's weak writing skills may negatively influence their students. Therefore, reinforcing teacher education by first determining pre-service teachers' writing weaknesses is imperative. This mixed-methods error analysis study aims to examine the cohesive errors in the writing…

  13. Family Cohesion, Adaptability and Composition in Adolescents from Callao, Peru

    Science.gov (United States)

    Villarreal-Zegarra, David; Paz-Jesús, Angel

    2017-01-01

    The objective of the study was to analyze if there are significant differences between family cohesion and adaptability according to the type of family composition (nuclear, extended, single parent and non-nuclear). This is a non-experimental and empirical research, in which a non-probabilistic, cross-sectional, selective and associative strategy…

  14. Writing Cohesion Using Content Lexical Ties in ESOL.

    Science.gov (United States)

    Liu, Dilin

    2000-01-01

    Describes a series of exercises that have proved useful in helping students learning English to enhance their writing skills, particularly cohesion in their writing. Exercises enabled students to learn words in context or in relation to one another as synonyms, antonyms, superordinates, or hyponyms, and a better understanding of these words…

  15. Social cohesion, sexuality, homophobia and women's sport in South ...

    African Journals Online (AJOL)

    ... secondly, that the success of national teams and athletes promotes national pride and unity. ... We explore these issues by drawing on media reports of cases in which ... To realise the potential of sport as a tool for building social cohesion, ...

  16. Cohesion and device reliability in organic bulk heterojunction photovoltaic cells

    KAUST Repository

    Brand, Vitali

    2012-04-01

    The fracture resistance of P3HT:PC 60BM-based photovoltaic devices are characterized using quantitative adhesion and cohesion metrologies that allow identification of the weakest layer or interface in the device structure. We demonstrate that the phase separated bulk heterojunction layer is the weakest layer and report quantitative cohesion values which ranged from ∼1 to 20 J m -2. The effects of layer thickness, composition, and annealing treatments on layer cohesion are investigated. Using depth profiling and X-ray photoelectron spectroscopy on the resulting fracture surfaces, we examine the gradient of molecular components through the thickness of the bulk heterojunction layer. Finally, using atomic force microscopy we show how the topography of the failure path is related to buckling of the metal electrode and how it develops with annealing. The research provides new insights on how the molecular design, structure and composition affect the cohesive properties of organic photovoltaics. © 2011 Elsevier B.V. All rights reserved.

  17. Botswana team sport players' perception of cohesion and imagery ...

    African Journals Online (AJOL)

    Perception of cohesion and imagery use among 45 elite team sport players in Botswana were assessed with the Group Environment Questionnaire (Carron et al., 1985) and the Sport Imagery Questionnaire (Hall et al., 1998) to determine whether a relationship exists between the variables, and whether imagery use will ...

  18. Leadership, Cohesion, and Team Norms Regarding Cheating and Aggression.

    Science.gov (United States)

    Shields, David Lyle Light; And Others

    1995-01-01

    Study explored leadership, cohesion, and demographic variables in relation to team norms about cheating and aggression. Surveys of high school and college ball players indicated that older age, higher year in school, and more years playing ball correlated positively with expectations of peer cheating and aggression. (SM)

  19. The Relationship between Task Cohesion and Competitive State Anxiety.

    Science.gov (United States)

    Eys, Mark A.; Hardy, James; Carron, Albert V.; Beauchamp, Mark R.

    2003-01-01

    Examined the association between athlete perceptions of task cohesiveness (Individual Attractions to the Group-Task and Group Integration-Task) and the degree to which they viewed their perceptions of the presence of pre-competition anxiety symptoms as facilitative or debilitative. Survey data indicated that the more positive their perceptions of…

  20. A cohesive finite element formulation for modelling fracture and ...

    Indian Academy of Sciences (India)

    cohesive elements experience material softening and lose their stress carrying capacity. A few simple ..... In the present work, a Lagrangian finite element procedure is employed. In this formu clation ...... o, is related to 'c o by,. 't o='c o ¼ 1 ہ. 1.

  1. Sense of Cohesion among Community Activists Engaging in Volunteer Activity

    Science.gov (United States)

    Levy, Drorit; Itzhaky, Haya; Zanbar, Lea; Schwartz, Chaya

    2012-01-01

    The present article attempts to shed light on the direct and indirect contribution of personal resources and community indices to Sense of Cohesion among activists engaging in community volunteer work. The sample comprised 481 activists. Based on social systems theory, three levels of variables were examined: (1) inputs, which included personal…

  2. Family Cohesion and Level of Communication Between Parents and ...

    African Journals Online (AJOL)

    This study investigated the level of communication between parents and their adolescent children and how such communication affects family cohesion. A sample of 200 subjects made up of adolescents and parents were selected through cluster, stratified and random sampling techniques from ten Local Government Areas ...

  3. Simulating Dynamic Fracture in Oxide Fuel Pellets Using Cohesive Zone Models

    Energy Technology Data Exchange (ETDEWEB)

    R. L. Williamson

    2009-08-01

    It is well known that oxide fuels crack during the first rise to power, with continued fracture occurring during steady operation and especially during power ramps or accidental transients. Fractures have a very strong influence on the stress state in the fuel which, in turn, drives critical phenomena such as fission gas release, fuel creep, and eventual fuel/clad mechanical interaction. Recently, interest has been expressed in discrete fracture methods, such as the cohesive zone approach. Such models are attractive from a mechanistic and physical standpoint, since they reflect the localized nature of cracking. The precise locations where fractures initiate, as well as the crack evolution characteristics, are determined as part of the solution. This paper explores the use of finite element cohesive zone concepts to predict dynamic crack behavior in oxide fuel pellets during power-up, steady operation, and power ramping. The aim of this work is first to provide an assessment of cohesive zone models for application to fuel cracking and explore important numerical issues associated with this fracture approach. A further objective is to provide basic insight into where and when cracks form, how they interact, and how cracking effects the stress field in a fuel pellet. The ABAQUS commercial finite element code, which includes powerful cohesive zone capabilities, was used for this study. Fully-coupled thermo-mechanical behavior is employed, including the effects of thermal expansion, swelling due to solid and gaseous fission products, and thermal creep. Crack initiation is determined by a temperature-dependent maximum stress criterion, based on measured fracture strengths for UO2. Damage evolution is governed by a traction-separation relation, calibrated to data from temperature and burn-up dependent fracture toughness measurements. Numerical models are first developed in 2D based on both axisymmetric (to explore axial cracking) and plane strain (to explore radial

  4. Cohesion, Flexibility, and the Mediating Effects of Shared Visionand Compassionon Engagement Army Acquisition Teams

    Science.gov (United States)

    2015-04-01

    issues such as social desirability, negative affect, and acquiescence (Spector, 2006) in the analysis of final model. To test for multicollinearity ...emotional cohesion, cognitive cohesion, and flexibility) are independent with no multicollinearity issues. Development and test of structural

  5. An examination of the relationship between athlete leadership and cohesion using social network analysis.

    Science.gov (United States)

    Loughead, Todd M; Fransen, Katrien; Van Puyenbroeck, Stef; Hoffmann, Matt D; De Cuyper, Bert; Vanbeselaere, Norbert; Boen, Filip

    2016-11-01

    Two studies investigated the structure of different athlete leadership networks and its relationship to cohesion using social network analysis. In Study 1, we examined the relationship between a general leadership quality network and task and social cohesion as measured by the Group Environment Questionnaire (GEQ). In Study 2, we investigated the leadership networks for four different athlete leadership roles (task, motivational, social and external) and their association with task and social cohesion networks. In Study 1, the results demonstrated that the general leadership quality network was positively related to task and social cohesion. The results from Study 2 indicated positive correlations between the four leadership networks and task and social cohesion networks. Further, the motivational leadership network emerged as the strongest predictor of the task cohesion network, while the social leadership network was the strongest predictor of the social cohesion network. The results complement a growing body of research indicating that athlete leadership has a positive association with cohesion.

  6. The Effects Of Physical And Biological Cohesion On Bedforms

    Science.gov (United States)

    Parsons, D. R.; Schindler, R.; Baas, J.; Hope, J. A.; Malarkey, J.; Paterson, D. M.; Peakall, J.; Manning, A. J.; Ye, L.; Aspden, R.; Alan, D.; Bass, S. J.

    2014-12-01

    Most coastal sediments consist of complex mixtures of cohesionless sands, physically-cohesive clays and extra cellular polymeric substances (EPS) that impart biological cohesion. Yet, our ability to predict bedform dimensions in these substrates is reliant on predictions based exclusively on cohesionless sand. We present findings from the COHBED project - which explicitly examines how bedform dynamics are modified by natural cohesion. Our experimental results show that for ripples, height and length are inversely proportional to initial clay content and bedforms take longer to appear, with no ripples when clay content exceeds 18%. When clay is replaced by EPS the development time and time of first appearance of ripples both increase by two orders of magnitude, with no bedforms above 0.125% EPS. For dunes, height and length are also inversely proportional to initial substrate clay content, resulting in a transition from dunes to ripples normally associated with velocity decreases. Addition of low EPS concentrations into the substrate results in yet smaller bedforms at the same clay contents and at high EPS concentrations, biological cohesion supersedes all electrostatic bonding, and bedform size is no longer related to mud content. The contrast in physical and biological cohesion effects on bedform development result from the disparity between inter-particle electrostatic bonding of clay particles and EPS grain coating and strands that physically link sediments together, which effects winnowing rates as bedforms evolve. These findings have wide ranging implications for bedform predictions in both modern and ancient environments. Coupling of biological and morphological processes not only requires an understanding of how bedform dimensions influence biota and habitat, but also how benthic species can modify bedform dimensions. Consideration of both aspects provides a means in which fluid dynamics, sediment transport and ecosystem energetics can be linked to yield

  7. System size effects on the mechanical response of cohesive-frictional granular ensembles

    Directory of Open Access Journals (Sweden)

    Singh Saurabh

    2017-01-01

    Full Text Available Shear resistance in granular ensembles is a result of interparticle interaction and friction. However, even the presence of small amounts of cohesion between the particles changes the landscape of the mechanical response considerably. Very often such cohesive frictional (c-ϕ granular ensembles are encountered in nature as well as while handling and storage of granular materials in the pharmaceutical, construction and mining industries. Modeling of these c-ϕ materials, especially in engineering applications have relied on the oft-made assumption of a “continua” and have utilized the popular tenets of continuum plasticity theory. We present an experimental investigation on the fundamental mechanics of c-ϕ materials specifically; we investigate if there exists a system size effect and any additional length scales beyond the continuum length scale on their mechanical response. For this purpose, we conduct a series of 1-D compression (UC tests on cylindrical specimens reconstituted in the laboratory with a range of model particle–binder combinations such as sandcement, sand-epoxy, and glass ballotini-epoxy mixtures. Specimens are reconstituted to various diameters ranging from 10 mm to 150 mm (with an aspect ratio of 2 to a predefined packing fraction. In addition to the effect of the type of binder (cement, epoxy and system size, the mean particle size is also varied from 0.5 to 2.5 mm. The peak strength of these materials is significant as it signals the initiation of the cohesive-bond breaking and onset of mobilization of the inter particle frictional resistance. For these model systems, the peak strength is a strong function of the system size of the ensemble as well as the mean particle size. This intriguing observation is counter to the traditional notion of a continuum plastic typical granular ensemble. Microstructure studies in a computed-tomograph have revealed the existence of a web patterned ‘entangled-chain’ like structure

  8. System size effects on the mechanical response of cohesive-frictional granular ensembles

    Science.gov (United States)

    Singh, Saurabh; Kandasami, Ramesh Kannan; Mahendran, Rupesh Kumar; Murthy, Tejas

    2017-06-01

    Shear resistance in granular ensembles is a result of interparticle interaction and friction. However, even the presence of small amounts of cohesion between the particles changes the landscape of the mechanical response considerably. Very often such cohesive frictional (c-ϕ) granular ensembles are encountered in nature as well as while handling and storage of granular materials in the pharmaceutical, construction and mining industries. Modeling of these c-ϕ materials, especially in engineering applications have relied on the oft-made assumption of a "continua" and have utilized the popular tenets of continuum plasticity theory. We present an experimental investigation on the fundamental mechanics of c-ϕ materials specifically; we investigate if there exists a system size effect and any additional length scales beyond the continuum length scale on their mechanical response. For this purpose, we conduct a series of 1-D compression (UC) tests on cylindrical specimens reconstituted in the laboratory with a range of model particle-binder combinations such as sandcement, sand-epoxy, and glass ballotini-epoxy mixtures. Specimens are reconstituted to various diameters ranging from 10 mm to 150 mm (with an aspect ratio of 2) to a predefined packing fraction. In addition to the effect of the type of binder (cement, epoxy) and system size, the mean particle size is also varied from 0.5 to 2.5 mm. The peak strength of these materials is significant as it signals the initiation of the cohesive-bond breaking and onset of mobilization of the inter particle frictional resistance. For these model systems, the peak strength is a strong function of the system size of the ensemble as well as the mean particle size. This intriguing observation is counter to the traditional notion of a continuum plastic typical granular ensemble. Microstructure studies in a computed-tomograph have revealed the existence of a web patterned `entangled-chain' like structure, we argue that this ushers

  9. Investigation on the Effect of Drained Strength when Designing Sheet Pile Walls

    DEFF Research Database (Denmark)

    Iversen, Kirsten Malte; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    that the height, anchor force, and the maximum bending moment in the wall can be lowered significantly when the effective cohesion is increased above zero. However, as the cohesion increases, the drop in the moment levels off, which implies that the benefit obtained from investigations increasing the cohesion......Long sheet pile walls are constructed in the cities as an integrated part of deep excavations for e.g. parking lots, pumping stations, reservoirs, and cut and cover tunnels. To minimise costs, the strength of the soil needs to be determined in the best possible way. The drained strength of clay...... expressed by c and ϕ is often estimated as c 10% = 10%・cu, and found by estimations based on the soil describtion, respectively. However, due to possible slicken slides and tension cracks, c = 0 is used on the back side of the sheet pile wall. This reduces the strength significantly. A parametric study...

  10. Estimating cohesion in small groups using audio-visual nonverbal behavior

    NARCIS (Netherlands)

    Hung, H.; Gatica-Perez, D.

    2010-01-01

    Cohesiveness in teams is an essential part of ensuring the smooth running of task-oriented groups. Research in social psychology and management has shown that good cohesion in groups can be correlated with team effectiveness or productivity, so automatically estimating group cohesion for team

  11. Estimated strength of shear keys in concrete dams

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, D.D. [Hatch Energy, Niagara Falls, ON (Canada); Lum, K.K.Y. [BC Hydro, Burnaby, BC (Canada)

    2008-07-01

    BC Hydro requested that Hatch Energy review the seismic stability of Ruskin Dam which was constructed in 1930 at Hayward Lake in British Columbia. The concrete gravity dam is founded nearly entirely on rock in a narrow valley. The vertical joints between blocks are keyed and grouted. The strength of the shear keys was assessed when a non-linear finite element model found that significant forces were being transferred laterally to the abutments during an earthquake. The lateral transfer of loads to the abutment relies on the strength of the shear keys. The dynamic finite element analysis was used to determine the stability of the dam. A review of the shear strength measurements reported in literature showed that the measurements compared well to those obtained by BC Hydro from cores taken from Ruskin Dam. The cohesive strength obtained using the Griffith failure criteria was also in good agreement with both sets of measurements. A simple ultimate shear strength equation was developed using the Mohr-Coulomb failure criteria to determine combined cohesive and frictional strength of shear keys. Safety factors of 2.0 for static loads and 1.5 for seismic loads were proposed to reduce the ultimate strength to allowable values. It was concluded that given the relatively high shear strength established for the shear keys, the abutment rock or dam/abutment contact will control the amount of load which can arch to the abutments. 8 refs., 4 tabs., 5 figs.

  12. Psychobiological Assessment and Enhancement of Team Cohesion and Psychological Resilience in ROTC Cadets Using a Virtual-Reality Team Cohesion Test

    Science.gov (United States)

    2016-06-01

    Using a Virtual - Reality Team Cohesion Test PRINCIPAL INVESTIGATOR: Josh Woolley MD/PhD CONTRACTING ORGANIZATION: NORTHERN CALIFORNIA INSTITUTE SAN...Team Cohesion and Psychological Resilience in ROTC Cadets Using a Virtual - Reality Team Cohesion Test 5b. GRANT NUMBER W81XWH-15-1-0042 5c. PROGRAM...targets while flying a virtual air vehicle. No individual has access to all the necessary information or controls, so operating as a team is crucial

  13. Derivation of Path Independent Coupled Mix Mode Cohesive Laws from Fracture Resistance Curves

    DEFF Research Database (Denmark)

    Goutianos, Stergios

    2016-01-01

    A generalised approach is presented to derive coupled mixed mode cohesive laws described with physical parameters such as peak traction, critical opening, fracture energy and cohesive shape. The approach is based on deriving mix mode fracture resistance curves from an effective mix mode cohesive...... law at different mode mixities. From the fracture resistance curves, the normal and shear stresses of the cohesive laws can be obtained by differentiation. Since, the mixed mode cohesive laws are obtained from a fracture resistance curve (potential function), path independence is automatically...

  14. A consistent partly cracked XFEM element for cohesive crack growth

    DEFF Research Database (Denmark)

    Asferg, Jesper L.; Poulsen, Peter Noe; Nielsen, Leif Otto

    2007-01-01

    Present extended finite element method (XFEM) elements for cohesive crack growth may often not be able to model equal stresses on both sides of the discontinuity when acting as a crack-tip element. The authors have developed a new partly cracked XFEM element for cohesive crack growth with extra...... enrichments to the cracked elements. The extra enrichments are element side local and were developed by superposition of the standard nodal shape functions for the element and standard nodal shape functions for a sub-triangle of the cracked element. With the extra enrichments, the crack-tip element becomes...... capable of modelling variations in the discontinuous displacement field on both sides of the crack and hence also capable of modelling the case where equal stresses are present on each side of the crack. The enrichment was implemented for the 3-node constant strain triangle (CST) and a standard algorithm...

  15. Numerical simulation of particle settling and cohesion in liquid

    Energy Technology Data Exchange (ETDEWEB)

    Johno, Y; Nakashima, K; Shigematsu, T; Ono, B [SASEBO National College of Technology, 1-1 Okishin, Sasebo, Nagasaki, 857-1193 (Japan); Satomi, M, E-mail: yjohno@post.cc.sasebo.ac.j [Sony Semiconductor Kyushu Corporation, Kikuchigun, Kumamoto (Japan)

    2009-02-01

    In this study, the motions of particles and particle clusters in liquid were numerically simulated. The particles of two sizes (Dp=40mum and 20mum) settle while repeating cohesion and dispersion, and finally the sediment of particles are formed at the bottom of a hexahedron container which is filled up with pure water. The flow field was solved with the Navier-Stokes equations and the particle motions were solved with the Lagrangian-type motion equations, where the interaction between fluid and particles due to drag forces were taken into account. The collision among particles was calculated using Distinct Element Method (DEM), and the effects of cohesive forces by van der Waals force acting on particle contact points were taken into account. Numerical simulations were performed under conditions in still flow and in shear flow. It was found that the simulation results enable us to know the state of the particle settling and the particle condensation.

  16. Cohesive fracture model for functionally graded fiber reinforced concrete

    International Nuclear Information System (INIS)

    Park, Kyoungsoo; Paulino, Glaucio H.; Roesler, Jeffery

    2010-01-01

    A simple, effective, and practical constitutive model for cohesive fracture of fiber reinforced concrete is proposed by differentiating the aggregate bridging zone and the fiber bridging zone. The aggregate bridging zone is related to the total fracture energy of plain concrete, while the fiber bridging zone is associated with the difference between the total fracture energy of fiber reinforced concrete and the total fracture energy of plain concrete. The cohesive fracture model is defined by experimental fracture parameters, which are obtained through three-point bending and split tensile tests. As expected, the model describes fracture behavior of plain concrete beams. In addition, it predicts the fracture behavior of either fiber reinforced concrete beams or a combination of plain and fiber reinforced concrete functionally layered in a single beam specimen. The validated model is also applied to investigate continuously, functionally graded fiber reinforced concrete composites.

  17. The limits of social capital: Durkheim, suicide, and social cohesion.

    Science.gov (United States)

    Kushner, Howard I; Sterk, Claire E

    2005-07-01

    Recent applications of social capital theories to population health often draw on classic sociological theories for validation of the protective features of social cohesion and social integration. Durkheim's work on suicide has been cited as evidence that modern life disrupts social cohesion and results in a greater risk of morbidity and mortality-including self-destructive behaviors and suicide. We argue that a close reading of Durkheim's evidence supports the opposite conclusion and that the incidence of self-destructive behaviors such as suicide is often greatest among those with high levels of social integration. A reexamination of Durkheim's data on female suicide and suicide in the military suggests that we should be skeptical about recent studies connecting improved population health to social capital.

  18. Erosion of cohesive soil layers above underground conduits

    Directory of Open Access Journals (Sweden)

    Luu Li-Hua

    2017-01-01

    Full Text Available Using a recently developed 2D numerical modelling that combines Discrete Element (DEM and Lattice Boltzmann methods (LBM, we simulate the destabilisation by an hydraulic gradient of a cohesive granular soil clogging the top of an underground conduit. We aim to perform a multi-scale study that relates the grain scale behavior to the macroscopic erosion process. In particular, we study the influence of the flow conditions and the inter-particle contact forces intensity on the erosion kinetic.

  19. Erosion of cohesive soil layers above underground conduits

    Science.gov (United States)

    Luu, Li-Hua; Philippe, Pierre; Noury, Gildas; Perrin, Jérôme; Brivois, Olivier

    2017-06-01

    Using a recently developed 2D numerical modelling that combines Discrete Element (DEM) and Lattice Boltzmann methods (LBM), we simulate the destabilisation by an hydraulic gradient of a cohesive granular soil clogging the top of an underground conduit. We aim to perform a multi-scale study that relates the grain scale behavior to the macroscopic erosion process. In particular, we study the influence of the flow conditions and the inter-particle contact forces intensity on the erosion kinetic.

  20. Social cohesion and civil law: marriage, divorce and religious courts

    OpenAIRE

    Douglas, Gillian; Doe, Christopher Norman; Gilliat-Ray, Sophie; Sandberg, Russell; Khan, Asma

    2011-01-01

    This Cardiff University study of religious courts and tribunals across the UK has been funded by the AHRC/ESRC Religion and Society Programme. The project, „Social Cohesion and Civil Law: Marriage, Divorce and Religious Courts‟, explores how religious law functions alongside civil law in England and Wales.\\ud The context, though not the catalyst, for our study, is the lecture given by the Archbishop of Canterbury in 2008 on the relationship between religious law - primarily though not exclusi...

  1. Family Change and Implications for Family Solidarity and Social Cohesion

    Directory of Open Access Journals (Sweden)

    Ravanera, Zenaida

    2008-01-01

    Full Text Available EnglishSocial cohesion can be viewed in terms of common projects and networks of social relations that characterize families, communities and society. In the past decades, the basis for family cohesion has shifted from organic to mechanical or from breadwinner to collaborative model. As in many Western countries, data on family change in Canada point to a greater flexibility in the entry and exit from relationships, a delay in the timing of family events, and a diversity of family forms. After looking at changes in families and in the family setting of individuals, the paper considers both intra-family cohesion and families as basis for social cohesion. Implications are raised for adults, children and publicp olicy.FrenchLa cohésion sociale peut se voir à travers les projets communs et les réseaux desrelations sociales qui caractérisent les familles, les communautés et les sociétés.La base de cohésion familiale est passée d’organique à mécanique, pour utiliserles termes de Durkheim, ou vers un modèle de collaboration plutôt qu’unepartage asymétrique de tâches. Comme dans d’autres sociétés orientales, lafamille au Canada est devenue plus flexible par rapport aux entrées et sortiesd’unions, il y a un délais dans les événements familiaux, et une variété deformes de familles. Après un regard sur les changements dans les familles etdans la situation familiale des individus, nous considérons la cohésion intrafamilialeet la famille comme base de cohésion sociale. Nous discutons desimpacts sur les adultes, les enfants et la politique publique.

  2. Multiple intersecting cohesive discontinuities in 3D reservoir geomechanics

    OpenAIRE

    Das, K. C.; Sandha, S.S.; Carol, Ignacio; Vargas, P.E.; Gonzalez, Nubia Aurora; Rodrigues, E.; Segura Segarra, José María; Lakshmikantha, Ramasesha Mookanahallipatna; Mello,, U.

    2013-01-01

    Reservoir Geomechanics is playing an increasingly important role in developing and producing hydrocarbon reserves. One of the main challenges in reservoir modeling is accurate and efficient simulation of arbitrary intersecting faults. In this paper, we propose a new formulation to model multiple intersecting cohesive discontinuities (faults) in reservoirs using the XFEM framework. This formulation involves construction of enrichment functions and computation of stiffness sub-matrices for bulk...

  3. The Process Architecture of EU Territorial Cohesion Policy

    Directory of Open Access Journals (Sweden)

    Andreas Faludi

    2010-08-01

    Full Text Available When preparing the European Spatial Development Perspective (ESDP, Member States were supported by the European Commission but denied the EU a competence in the matter. Currently, the Treaty of Lisbon identifies territorial cohesion as a competence shared between the Union and the Member States. This paper is about the process architecture of territorial cohesion policy. In the past, this architecture resembled the Open Method of Coordination (OMC which the White Paper on European Governance praised, but only in areas where there was no EU competence. This reflected zero-sum thinking which may continue even under the Lisbon Treaty. After all, for as long as territorial cohesion was not a competence, voluntary cooperation as practiced in the ESDP process was pursued in this way. However, the practice of EU policies, even in areas where there is an EU competence, often exhibits features of the OMC. Surprisingly effective innovations hold the promise of rendering institutions of decision making comprehensible and democratically accountable. In the EU as a functioning polity decision making is thus at least part deliberative so that actors’ preferences are transformed by the force of the better argument. This brings into focus the socialisation of the deliberators into epistemic communities. Largely an informal process, this is reminiscent of European spatial planning having been characterised as a learning process.

  4. Influence of magnetic cohesion on the stability of granular slopes.

    Science.gov (United States)

    Taylor, K; King, P J; Swift, Michael R

    2008-09-01

    We use a molecular dynamics model to simulate the formation and evolution of a granular pile in two dimensions in order to gain a better understanding of the role of magnetic interactions in avalanche dynamics. We find that the angle of repose increases only slowly with magnetic field; the increase in angle is small even for intergrain cohesive forces many times stronger than gravity. The magnetic forces within the bulk of the pile partially cancel as a result of the anisotropic nature of the dipole-dipole interaction between grains. However, we show that this cancellation effect is not sufficiently strong to explain the discrepancy between the angle of repose in wet systems and magnetically cohesive systems. In our simulations we observe shearing deep within the pile, and we argue that it is this motion that prevents the angle of repose from increasing dramatically. We also investigate different implementations of friction with the front and back walls of the container, and conclude that the nature of the friction dramatically affects the influence of magnetic cohesion on the angle of repose.

  5. The Role of Lexical Cohesion in Writing Quality

    Directory of Open Access Journals (Sweden)

    Hmoud Alotaibi

    2015-01-01

    Full Text Available The idea of whether repetition has any relation with the writing quality of the text has remained an issue that intrigues a number of scholars in linguistics and in writing studies. Michael Hoey (1991, Halliday and Hasan (1976 are two prominent works in presenting detailed and thoughtful analysis of repetition occurrences in the text. This study uses a model of lexical cohesion proposed by Witte and Faigley (1981 which itself is based on the taxonomies of cohesive ties presented by Halliday and Hasan (1976.  The model deals with lexical cohesion and its subclasses, namely, repetition (same type, synonym, near-synonym, super-ordinate item, and general item and collocation. The corpus includes five argumentative essays written by students in the field of English language literature. Five teaching assistants were asked to rank the papers on a five-point scale based on their perception of the papers’ writing quality. The results showed that the paper that received the lowest rating in terms of the writing quality was the one that included the largest number of repetition occurrences of the same type. The study concludes by arguing that repetition may not be considered as monolithic, and suggests that every type of repetition needs to be examined individually in order to determine what enhances and what deteriorates the writing quality.

  6. An examination of the cohesion-performance relationship in university hockey teams.

    Science.gov (United States)

    Slater, M R; Sewell, D F

    1994-10-01

    The objective of this study was to assess, using the Group Environment Questionnaire, whether team cohesion in university-level field hockey was a cause for, or an effect of, successful performance. A quasi-experimental longitudinal design with cross-lagged correlational analysis was adopted and measures of cohesion and performance were taken midway and later in the season. The results of the synchronous correlations showed a positive relationship (with good stationarity) between team cohesion and performance outcome. Although non-significant cross-lagged differentials indicated a circular relationship, the magnitudes of both the cross-lagged correlations and the partial correlations, together with multiple-regression analyses, revealed that the stronger flow was from cohesion to performance. The socially oriented aspects of cohesion, in particular, had significant associations with performance. The results imply that cohesion-performance relationships should be examined within a circular model, in which cohesion and performance are interdependent.

  7. Technology for Boundaries

    DEFF Research Database (Denmark)

    Bødker, Susanne; Kristensen, Jannie Friis; Nielsen, Christina

    2003-01-01

    .After analysing the history and the current boundary work, the paper will propose new technological support for boundary work. In particular the paper will suggest means of supporting boundaries when these are productive and for changing boundaries when this seems more appropriate. In total, flexible technologies......This paper presents a study of an organisation, which is undergoing a process transforming organisational and technological boundaries. In particular, we shall look at three kinds of boundaries: the work to maintain and change the boundary between the organisation and its customers; boundaries...... seem a core issue when dealing with technology for boundaries....

  8. Attitude Strength.

    Science.gov (United States)

    Howe, Lauren C; Krosnick, Jon A

    2017-01-03

    Attitude strength has been the focus of a huge volume of research in psychology and related sciences for decades. The insights offered by this literature have tremendous value for understanding attitude functioning and structure and for the effective application of the attitude concept in applied settings. This is the first Annual Review of Psychology article on the topic, and it offers a review of theory and evidence regarding one of the most researched strength-related attitude features: attitude importance. Personal importance is attached to an attitude when the attitude is perceived to be relevant to self-interest, social identification with reference groups or reference individuals, and values. Attaching personal importance to an attitude causes crystallizing of attitudes (via enhanced resistance to change), effortful gathering and processing of relevant information, accumulation of a large store of well-organized relevant information in long-term memory, enhanced attitude extremity and accessibility, enhanced attitude impact on the regulation of interpersonal attraction, energizing of emotional reactions, and enhanced impact of attitudes on behavioral intentions and action. Thus, important attitudes are real and consequential psychological forces, and their study offers opportunities for addressing behavioral change.

  9. Structural characteristics of cohesive flow deposits, and a sedimentological approach on their flow mechanisms.

    Science.gov (United States)

    Tripsanas, E. K.; Bryant, W. R.; Prior, D. B.

    2003-04-01

    A large number of Jumbo Piston cores (up to 20 m long), acquired from the continental slope and rise of the Northwest Gulf of Mexico (Bryant Canyon area and eastern Sigsbee Escarpment), have recovered various mass-transport deposits. The main cause of slope instabilities over these areas is oversteepening of the slopes due to the seaward mobilization of the underlying allochthonous salt masses. Cohesive flow deposits were the most common recoveries in the sediment cores. Four types of cohesive flow deposits have been recognized: a) fluid debris flow, b) mud flow, c) mud-matrix dominated debris flow, and d) clast-dominated debris flow deposits. The first type is characterized by its relatively small thickness (less than 1 m), a mud matrix with small (less than 0.5 cm) and soft mud-clasts, and a faint layering. The mud-clasts reveal a normal grading and become more abundant towards the base of each layer. That reveals that their deposition resulted by several successive surges/pulses, developed in the main flow, than the sudden “freezing” of the whole flow. The main difference between mud flow and mud-matrix dominated debris flow deposits is the presence of small to large mud-clasts in the later. Both deposits consist of a chaotic mud-matrix, and a basal shear laminated zone, where the strongest shearing of the flow was exhibited. Convolute laminations, fault-like surfaces, thrust faults, and microfaults are interpreted as occurring during the “freezing” of the flows and/or by adjustments of the rested deposits. Clast-dominated debris flow deposits consist of three zones: a) an upper plug-zone, characterized by large interlocked clasts, b) a mid-zone, of higher reworked, inversely graded clasts, floating in a mud-matrix, and c) a lower shear laminated zone. The structure of the last three cohesive flow deposits indicate that they represent deposition of typical Bingham flows, consisting of an upper plug-zone in which the yield stress is not exceeded and an

  10. Neighbourhood cohesion and mental wellbeing among older adults: a mixed methods approach.

    Science.gov (United States)

    Elliott, Jane; Gale, Catharine R; Parsons, Samantha; Kuh, Diana

    2014-04-01

    There is now a body of evidence that demonstrates strong links between neighbourhood characteristics and mental health and wellbeing. There is an increasing interest in how this relationship varies for individuals of different ages. Understanding the link between neighbourhood and wellbeing for older adults is of particular significance, given the changing age structure of the population and the desire among policy makers and practitioners to promote healthy and active ageing. This paper provides further evidence on the nature and strength of the link between individual perceptions of neighbourhood belonging and mental wellbeing among those over age fifty using both qualitative and quantitative data from three British cohort studies. Between 2008 and 2011 quantitative data were collected from 10,312 cohort members, and 230 of them took part in qualitative biographical interviews. Quantitative analysis confirms that there is a moderate association between neighbourhood cohesion and wellbeing measured at the individual level in each of the three cohorts. This association persists after controlling for a range of covariates including personality. The association between neighbourhood cohesion and wellbeing is stronger for individuals in the older two cohorts than in the younger cohort. Using qualitative biographical interviews with 116 men and 114 women we illustrate how individuals talk about their sense of neighbourhood belonging. The importance of social participation as a mechanism for promoting neighbourhood belonging, and the use of age and life stage as characteristics to describe and define neighbours, is clear. In addition, the qualitative interviews point to the difficulties of using a short battery of questions to capture the varied and multi-dimensional nature of neighbourhood relations. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Stratification of TAD boundaries reveals preferential insulation of super-enhancers by strong boundaries.

    Science.gov (United States)

    Gong, Yixiao; Lazaris, Charalampos; Sakellaropoulos, Theodore; Lozano, Aurelie; Kambadur, Prabhanjan; Ntziachristos, Panagiotis; Aifantis, Iannis; Tsirigos, Aristotelis

    2018-02-07

    The metazoan genome is compartmentalized in areas of highly interacting chromatin known as topologically associating domains (TADs). TADs are demarcated by boundaries mostly conserved across cell types and even across species. However, a genome-wide characterization of TAD boundary strength in mammals is still lacking. In this study, we first use fused two-dimensional lasso as a machine learning method to improve Hi-C contact matrix reproducibility, and, subsequently, we categorize TAD boundaries based on their insulation score. We demonstrate that higher TAD boundary insulation scores are associated with elevated CTCF levels and that they may differ across cell types. Intriguingly, we observe that super-enhancers are preferentially insulated by strong boundaries. Furthermore, we demonstrate that strong TAD boundaries and super-enhancer elements are frequently co-duplicated in cancer patients. Taken together, our findings suggest that super-enhancers insulated by strong TAD boundaries may be exploited, as a functional unit, by cancer cells to promote oncogenesis.

  12. Sub-critical cohesive crack propagation with hydro-mechanical coupling and friction

    Directory of Open Access Journals (Sweden)

    S. Valente

    2016-01-01

    Full Text Available Looking at the long-time behaviour of a dam, it is necessary to assume that the water can penetrate a possible crack washing away some components of the concrete. This type of corrosion reduces the tensile strength and fracture energy of the concrete compared to the same parameters measured during a short-time laboratory test. This phenomenon causes the so called sub-critical crack propagation. That is the reason why the International Commission of Large Dams recommends to neglect the tensile strength of the joint between the dam and the foundation, which is the weakest point of a gravity dam. In these conditions a shear displacement discontinuity starts growing in a point, called Fictitious Crack Tip (shortened FCT, which is still subjected to a compression stress. In order to manage this problem, in this paper the cohesive crack model is re-formulated with the focus on the shear stress component. In this context, the classical Newton-Raphson method fails to converge to an equilibrium state. Therefore the approach used is based on two stages: (a a global one in which the FCT is moved ahead of one increment; (b a local one in which the non-linear conditions occurring in the Fracture Process Zone are taken into account. This two-stage approach, which is known in the literature as a Large Time Increment method, is able to model three different mechanical regimes occurring during the crack propagation between a dam and the foundation rock.

  13. Relative scale and the strength and deformability of rock masses

    Science.gov (United States)

    Schultz, Richard A.

    1996-09-01

    The strength and deformation of rocks depend strongly on the degree of fracturing, which can be assessed in the field and related systematically to these properties. Appropriate Mohr envelopes obtained from the Rock Mass Rating (RMR) classification system and the Hoek-Brown criterion for outcrops and other large-scale exposures of fractured rocks show that rock-mass cohesive strength, tensile strength, and unconfined compressive strength can be reduced by as much as a factor often relative to values for the unfractured material. The rock-mass deformation modulus is also reduced relative to Young's modulus. A "cook-book" example illustrates the use of RMR in field applications. The smaller values of rock-mass strength and deformability imply that there is a particular scale of observation whose identification is critical to applying laboratory measurements and associated failure criteria to geologic structures.

  14. Moralized Health-Related Persuasion Undermines Social Cohesion

    Directory of Open Access Journals (Sweden)

    Susanne Täuber

    2018-06-01

    Full Text Available Integrating theory and research on persuasion, moralization, and intergroup relations, the present research aims to highlight the far-reaching impact of health-related persuasion on society. I propose that governments’ health-related persuasion leads to the emergence of new social norms, and in particular moral norms. Importantly, moral norms provide strong behavioral imperatives and are seen as binding for group members. This suggests that moralized persuasion has a strong potential to divide society along the lines of citizens who conform to and citizens who deviate from health-related moral norms. Thus, departing from the traditional focus on targets of persuasion, the present research focuses on those holding a moralized view on health and lifestyle. Key aspects of social cohesion as defined by the OECD (2011 have been tested across four studies. The main hypothesis tested is that those conforming to the norm (e.g., non-smokers, normal weight people, people with healthy lifestyles will stigmatize those deviating from the norm (e.g., smokers, overweight people, people with unhealthy lifestyles. Flowing from stigmatization, less inclusion, lower solidarity with and greater endorsement of unequal treatment of those deviating from the moral norm are predicted. Four survey studies (total N = 1568 examining the proposed associations among non-smokers, normal weight people, and employees with healthy lifestyles are presented. The studies provide unanimous support for the hypothesis, with meta-analysis providing further support for the reliability of the findings. Consistent across studies, social cohesion indicators were negatively affected by health moralization through stigmatization of those deviating from health-related moral norms. Findings highlight an under-acknowledged potential of moralized health-related persuasion to divide society, thereby undermining cohesion and the achievement of important societal goals. In the discussion

  15. Applying automatic item generation to create cohesive physics testlets

    Science.gov (United States)

    Mindyarto, B. N.; Nugroho, S. E.; Linuwih, S.

    2018-03-01

    Computer-based testing has created the demand for large numbers of items. This paper discusses the production of cohesive physics testlets using an automatic item generation concepts and procedures. The testlets were composed by restructuring physics problems to reveal deeper understanding of the underlying physical concepts by inserting a qualitative question and its scientific reasoning question. A template-based testlet generator was used to generate the testlet variants. Using this methodology, 1248 testlet variants were effectively generated from 25 testlet templates. Some issues related to the effective application of the generated physics testlets in practical assessments were discussed.

  16. Cucker-Smale Flocking with Bounded Cohesive and Repulsive Forces

    Directory of Open Access Journals (Sweden)

    Qiang Song

    2013-01-01

    Full Text Available This paper proposes two Cucker-Smale-type flocking models by introducing both cohesive and repulsive forces to second-order multiagent systems. Under some mild conditions on the initial state of the flocking system, it is shown that the velocity consensus of the agents can be reached independent of the parameter which describes the decay of communication rates. In particular, the collision between any two agents can always be avoided by designing an appropriate bounded repulsive function based on the initial energy of the flock. Numerical examples are given to demonstrate the effectiveness of the theoretical analysis.

  17. A Test to Express Diagnostic Cohesion of Football Team

    OpenAIRE

    Alexandra O. Savinkina

    2017-01-01

    We proposed to assess the cohesion of a football team by its subject-goal and subject-value unity according to the A.V. Petrovsky theory. Goal unity was measured by the degree of compliance of the priority targets for various players in the team. Values were estimated by the coincidence of the ideas about a perfect football player. On the basis of the provisional diagnosis of the six teams, we had made the lists of goals and values. The tests were piloted on 35 football teams. The results all...

  18. Interactive effects of team cohesion on perceived efficacy in semi-professional sport.

    Science.gov (United States)

    Marcos, Francisco Miguel Leo; Miguel, Pedro Antonio Sánchez; Oliva, David Sánchez; Calvo, Tomás García

    2010-01-01

    The present study examined the relationships among cohesion, self-efficacy, coaches' perceptions of their players' efficacy at the individual level and athletes' perceptions of their teammates' efficacy. Participants (n = 76) recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and social cohesion. Regression analysis results suggest task cohesion positively related to coaches and teammate's perception of efficacy. These results have implications for practitioners in terms of the importance of team building to enhance team cohesion and feelings of efficacy. Key pointsThis paper increases the knowledge about soccer and basketball match analysis.Give normative values to establish practice and match objectives.Give applications ideas to connect research with coaches' practice.

  19. Group cohesion and starting status in successful and less successful elite volleyball teams.

    Science.gov (United States)

    Spink, K S

    1992-08-01

    The main purpose of this study was to examine the relationship between members' perceptions of group cohesion and starting status in elite volleyball teams. The results of the study revealed that the form of the cohesion-starting status relationship was moderated by the variable of success. The results for less successful teams revealed that differences did emerge between specific measures of cohesion endorsed by starters and non-starters. No such differences in cohesion emerged when the starters and non-starters on successful teams were compared. These results provide initial support for the suggestion that the most successful teams are the ones where the perceptions of cohesiveness by starters and non-starters are similar. A secondary purpose of the study was to determine whether those teams that were the most successful and similar in their members' perceptions of cohesiveness, were also the teams whose members have the most positive outcome expectancy. The results supported this prediction.

  20. Species type controls root strength and influences slope stability in coastal Ecuador

    Science.gov (United States)

    Anttila, E.; Wray, M. E.; Knappe, E.; Ogasawara, T.; Tholt, A.; Cliffe, B.; Oshun, J.

    2014-12-01

    Tree roots, particular those of old growth trees, provide significant cohesive strength that can prevent shallow landslides. Little is known about the root strength of trees growing in dry tropical forests. In 1997, Bahía de Caráquez, Ecuador experienced a large landslide, which may have been precipitated by massive deforestation along the Ecuadorian coast. We used a tensile spring apparatus combined with root maps to caclulate the cohesive strength of different native species of trees. Whereas the results show the previously reported power law relationship between root diameter and tensile strength, our data also reveals new contributions. First, we find that trees have far stronger and more abundant roots than neighboring bushes, and thus add far more cohesive strength to the hillslope. Furthermore, there is a wide range of tensile strength among the native trees measured, with algarrobo having the strongest roots, and ceibo gernally being weak rooted. Finally, we use a slope stability model to predict failure conditions considering the strength added to a hillslope if vegetation is predominantly composed of bushes, algarrobo, or ceibo. Our results, which are the first of their kind for the Ecuadorian dry tropical forest, will be used to guide the ongoing native reforestation efforts of Global Student Embassy. Our unique partnership with Global Student Embassy connects our field study to practical land use decisions that will lead to increased slope and decreased human danger along coastal Ecuador's dry tropical forest.

  1. Relationship Among Team Collective Efficacy, Cohesion, and Coaching Competency in Sports

    OpenAIRE

    Manning, Clayton T.

    2007-01-01

    A team's performance in any sport can be predicted by many factors. Some of these factors include team collective efficacy, team cohesiveness, and coaching competency. Currently, there is little research investigating the relationships among teams' beliefs about their capabilities, their level of cohesion, and their perceptions of coaching competency on overall sport performance. The purpose of this study was to document the relationship among collective efficacy, cohesion, and coaching on sp...

  2. Interactive Effects of Team Cohesion on Perceived Efficacy in Semi-Professional Sport

    OpenAIRE

    Marcos, Francisco Miguel Leo; Miguel, Pedro Antonio Sánchez; Oliva, David Sánchez; Calvo, Tomás García

    2010-01-01

    The present study examined the relationships among cohesion, self-efficacy, coaches’ perceptions of their players’ efficacy at the individual level and athletes’ perceptions of their teammates’ efficacy. Participants (n = 76) recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and socia...

  3. A three-dimensional cohesive sediment transport model with data assimilation: Model development, sensitivity analysis and parameter estimation

    Science.gov (United States)

    Wang, Daosheng; Cao, Anzhou; Zhang, Jicai; Fan, Daidu; Liu, Yongzhi; Zhang, Yue

    2018-06-01

    Based on the theory of inverse problems, a three-dimensional sigma-coordinate cohesive sediment transport model with the adjoint data assimilation is developed. In this model, the physical processes of cohesive sediment transport, including deposition, erosion and advection-diffusion, are parameterized by corresponding model parameters. These parameters are usually poorly known and have traditionally been assigned empirically. By assimilating observations into the model, the model parameters can be estimated using the adjoint method; meanwhile, the data misfit between model results and observations can be decreased. The model developed in this work contains numerous parameters; therefore, it is necessary to investigate the parameter sensitivity of the model, which is assessed by calculating a relative sensitivity function and the gradient of the cost function with respect to each parameter. The results of parameter sensitivity analysis indicate that the model is sensitive to the initial conditions, inflow open boundary conditions, suspended sediment settling velocity and resuspension rate, while the model is insensitive to horizontal and vertical diffusivity coefficients. A detailed explanation of the pattern of sensitivity analysis is also given. In ideal twin experiments, constant parameters are estimated by assimilating 'pseudo' observations. The results show that the sensitive parameters are estimated more easily than the insensitive parameters. The conclusions of this work can provide guidance for the practical applications of this model to simulate sediment transport in the study area.

  4. A study on the strength properties of the rock mass based on triaxial tests conducted at the Horonobe Underground Research Laboratory

    International Nuclear Information System (INIS)

    Aoyagi, Kazuhei; Ishii, Eiichi; Fujita, Tomoo; Kondo, Keiji; Tsusaka, Kimikazu

    2015-03-01

    Japan Atomic Energy Agency (JAEA) has been conducting R and D activities at the off-site URL at Horonobe, Hokkaido, Japan in order to enhance reliability of technology related to deep geological disposal of HLW in sedimentary rocks. In this report, strength properties (cohesion and frictional angle) of rock masses in the Koetoi and Wakkanai formations are investigated on the basis of triaxial tests conducted in the Horonobe URL considering the relative depths to the formation. Strength properties investigated in this report are compared with the properties obtained in the designing phase. The cohesion in the Koetoi Formation increased with increasing depth. On the other hand, in the transition zone of the Wakkanai Formation, the cohesion increased significantly in the shallow Wakkanai formation (transition zone). Below the transition zone, the cohesion does not significantly depend on the depth. Thus the strength properties between two formations were found to be different. Comparing the cohesions and frictional angles determined from triaxial tests with the values determined in the designing phase, there was no agreement between these values in almost all the depth. Thus it is essential to determine cohesion and frictional angle considering the relative depths to the formation for detailed understanding of strength properties of rock mass. A CD-ROM is attached as an appendix. (J.P.N.)

  5. Microtensile bond strength of enamel after bleaching.

    Science.gov (United States)

    Lago, Andrea Dias Neves; Garone-Netto, Narciso

    2013-01-01

    To evaluate the bond strength of a composite resin to the bovine enamel bleached with 35% hydrogen peroxide. It was used an etching-and-rinse adhesive system employed immediately, 7 and 14 days after the bleaching. Twenty bovine teeth were randomly distributed into 4 groups (n = 5), 3 experimental and 1 control. G1: Unbleached + restoration 14 days after storage in artificial saliva (control); G2: Bleached + restoration immediately after bleaching; G3: Bleached + restoration 7 days after bleaching; G4: Bleached + restoration 14 days after bleaching. Their buccal enamel surfaces were flattened, and a 25 mm² (5 × 5 mm) area from each one of these regions was outlined so as to standardize the experimental region. Universal hybrid composite resin Filtek™Z350 was inserted into four layers of 1 mm each and photo-activated. The bond strength was quantitatively evaluated by a microtensile test (1.0 mm/min) 24 h after the restorative procedures. The failure mode was assessed through scanning electron microscopy (SEM). There was a significant reduction in the bond strength of the restored teeth immediately after the bleaching (G2). There were no significant differences in enamel bond strength between groups G1, G3, and G4. There was a predominance of adhesive and mixed (cohesive + adhesive) failure in all groups. The 7-day-period after the end of the bleaching with 35% hydrogen peroxide was enough to achieve the appropriate values of bond strength to the enamel.

  6. [Family cohesion associated with oral health, socioeconomic factors and health behavior].

    Science.gov (United States)

    Ferreira, Luale Leão; Brandão, Gustavo Antônio Martins; Garcia, Gustavo; Batista, Marília Jesus; Costa, Ludmila da Silva Tavares; Ambrosano, Gláucia Maria Bovi; Possobon, Rosana de Fátima

    2013-08-01

    Overall health surveys have related family cohesion to socio-economic status and behavioral factors. The scope of this study was to investigate the association between family cohesion and socio-economic, behavioral and oral health factors. This was a, cross-sectional study with two-stage cluster sampling. The random sample consisted of 524 adolescents attending public schools in the city of Piracicaba-SP. Variables were evaluated by self-applied questionnaires and caries and periodontal disease were assessed by DMF-T and CPI indices. The adolescent's perception of family cohesion was assessed using the family adaptability and cohesion scale. Univariate and multinomial logistic regression shows that adolescents with low family cohesion were more likely than those with medium family cohesion to have low income (OR 2,28 95% CI 1,14- 4,55), presence of caries (OR 2,23 95% CI 1,21-4,09), less than two daily brushings (OR 1,91 95% CI 1,03-3,54). Adolescents with high family cohesion were more likely than those with medium family cohesion to have high income and protective behavior against the habit of smoking. Thus, the data shows that adolescent perception of family cohesion was associated with behavioral, socio-economic and oral health variables, indicating the importance of an integral approach to patient health.

  7. Cohesive delamination and frictional contact on joining surface via XFEM

    Directory of Open Access Journals (Sweden)

    Francesco Parrinello

    2018-02-01

    Full Text Available In the present paper, the complex mechanical behaviour of the surfaces joining two differentbodies is analysed by a cohesive-frictional interface constitutive model. The kinematical behaviouris characterized by the presence of discontinuous displacement fields, that take place at the internalconnecting surfaces, both in the fully cohesive phase and in the delamination one. Generally, in order tocatch discontinuous displacement fields, internal connecting surfaces (adhesive layers are modelled bymeans of interface elements, which connect, node by node, the meshes of the joined bodies, requiringthe mesh to be conforming to the geometry of the single bodies and to the relevant connecting surface.In the present paper, the Extended Finite Element Method (XFEM is employed to model, both fromthe geometrical and from the kinematical point of view, the whole domain, including the connectedbodies and the joining surface. The joining surface is not discretized by specific finite elements, butit is defined as an internal discontinuity surface, whose spatial position inside the mesh is analyticallydefined. The proposed approach is developed for two-dimensional composite domains, formed by twoor more material portions joined together by means of a zero thickness adhesive layer. The numericalresults obtained with the proposed approach are compared with the results of the classical interfacefinite element approach. Some examples of delamination and frictional contact are proposed withlinear, circular and curvilinear adhesive layer.

  8. Improving the geotechnical behavior of sand through cohesive admixtures

    Directory of Open Access Journals (Sweden)

    Mohie eldin Mohamed Afify Elmashad

    2018-04-01

    Full Text Available Irrigation projects in Egypt have been facing tremendous challenges, mostly is the scarcity of irrigation water. The current research presents the effect of different cohesive admixture on the conductivity of siliceous sand in general and its other geotechnical properties. Two different types of conventional swelling clay from (Toshka, 6th of October as well as bentonite were used to construct the irrigation canals and embankment. The results indicated that increase in the plasticity properties of the treated soil also decrease the permeability and infiltration. Moreover, the dry density of 2.08 t/m3 was obtained from sand and 20% 6th of October mixture, also the CBR of 31.20% were obtained from sand and 8% 6th of October mixture. Increasing the bentonite ratio increases the cohesion and decreasing the permeability. The swelling ratios of sand 6th of October Clay mixture is equal to 0.28%, and the fictitious stress at which the swelling ratio is nil, is equal to 16 kPa. Keywords: Sand, Swelling clay, Bentonite, Compaction test, Consolidation test, Triaxial test

  9. Rigid supersymmetry with boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, D.V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Van Nieuwenhuizen, P. [State Univ. of New York, Stony Brook, NY (United States). C.N. Yang Inst. for Theoretical Physics

    2008-01-15

    We construct rigidly supersymmetric bulk-plus-boundary actions, both in x-space and in superspace. For each standard supersymmetric bulk action a minimal supersymmetric bulk-plus-boundary action follows from an extended F- or D-term formula. Additional separately supersymmetric boundary actions can be systematically constructed using co-dimension one multiplets (boundary superfields). We also discuss the orbit of boundary conditions which follow from the Euler-Lagrange variational principle. (orig.)

  10. Bond strength of masonry

    NARCIS (Netherlands)

    Pluijm, van der R.; Vermeltfoort, A.Th.

    1992-01-01

    Bond strength is not a well defined property of masonry. Normally three types of bond strength can be distinguished: - tensile bond strength, - shear (and torsional) bond strength, - flexural bond strength. In this contribution the behaviour and strength of masonry in deformation controlled uniaxial

  11. Effect of hot-humid exposure on static strength of adhesive-bonded aluminum alloys

    Directory of Open Access Journals (Sweden)

    Rui Zheng

    2015-09-01

    Full Text Available The effect of hot-humid exposure (i.e., 40 °C and 98% R.H. on the quasi-static strength of the adhesive-bonded aluminum alloys was studied. Test results show that the hot-humid exposure leads to the significant decrease in the joint strength and the change of the failure mode from a mixed cohesive and adhesive failure with cohesive failure being dominant to adhesive failure being dominant. Careful analyses of the results reveal that the physical bond is likely responsible for the bond adhesion between L adhesive and aluminum substrates. The reduction in joint strength and the change of the failure mode resulted from the degradation in bond adhesion, which was primarily attributed to the corrosion of aluminum substrate. In addition, the elevated temperature exposure significantly accelerated the corrosion reaction of aluminum, which accelerated the degradation in joint strength.

  12. Unit-level voluntary turnover rates and customer service quality: implications of group cohesiveness, newcomer concentration, and size.

    Science.gov (United States)

    Hausknecht, John P; Trevor, Charlie O; Howard, Michael J

    2009-07-01

    Despite substantial growth in the service industry and emerging work on turnover consequences, little research examines how unit-level turnover rates affect essential customer-related outcomes. The authors propose an operational disruption framework to explain why voluntary turnover impairs customers' service quality perceptions. On the basis of a sample of 75 work units and data from 5,631 employee surveys, 59,602 customer surveys, and organizational records, results indicate that unit-level voluntary turnover rates are negatively related to service quality perceptions. The authors also examine potential boundary conditions related to the disruption framework. Of 3 moderators studied (group cohesiveness, group size, and newcomer concentration), results show that turnover's negative effects on service quality are more pronounced in larger units and in those with a greater concentration of newcomers.

  13. Boundary organizations to boundary chains: Prospects for advancing climate science application

    Directory of Open Access Journals (Sweden)

    Christine J. Kirchhoff

    2015-01-01

    Full Text Available Adapting to climate change requires the production and use of climate information to inform adaptation decisions. By facilitating sustained interaction between science producers, boundary organizations narrow the gap between science and decision-making and foster the co-production of actionable knowledge. While traditional boundary organization approaches focused on intense one-on-one interactions between producers and users increases usability, this approach requires significant time and resources. Forming “boundary chains”, linking complimentary boundary organizations together, may reduce those costs. In this paper, we use longitudinal observations of a boundary chain, interviews and surveys to explore: (1 how producer-user interactions increase understanding and information usability and (2 if and how efficiencies in climate information production, dissemination and use arise as a result of the boundary chain. We find that forming and sustaining an effective boundary chain requires not only interest, commitment and investment from every link in the chain but also a level of non-overlapping mutual dependency and complementary skill sets. In this case, GLISA’s strength in producing scientific information and their credibility as climate scientists and HRWC’s strengths in facilitation, connection with potential information users, and their recognition and reputation in the watershed add value to the boundary chain enabling the boundary chain to accomplish more with greater efficiency than if each organization in the chain tried to work independently. Finally, data show how the boundary chain increased efficiencies in educating potential users about the strengths and limitations of climate science and improving the production, dissemination, and use of climate information.

  14. Investigating the settling dynamics of cohesive silt particles with particle-resolving simulations

    Science.gov (United States)

    Sun, Rui; Xiao, Heng; Sun, Honglei

    2018-01-01

    The settling of cohesive sediment is ubiquitous in aquatic environments, and the study of the settling process is important for both engineering and environmental reasons. In the settling process, the silt particles show behaviors that are different from non-cohesive particles due to the influence of inter-particle cohesive force. For instance, the flocs formed in the settling process of cohesive silt can loosen the packing, and thus the structural densities of cohesive silt beds are much smaller than that of non-cohesive sand beds. While there is a consensus that cohesive behaviors depend on the characteristics of sediment particles (e.g., Bond number, particle size distribution), little is known about the exact influence of these characteristics on the cohesive behaviors. In addition, since the cohesive behaviors of the silt are caused by the inter-particle cohesive forces, the motions of and the contacts among silt particles should be resolved to study these cohesive behaviors in the settling process. However, studies of the cohesive behaviors of silt particles in the settling process based on particle-resolving approach are still lacking. In the present work, three-dimensional settling process is investigated numerically by using CFD-DEM (Computational Fluid Dynamics-Discrete Element Method). The inter-particle collision force, the van der Waals force, and the fluid-particle interaction forces are considered. The numerical model is used to simulate the hindered settling process of silt based on the experimental setup in the literature. The results obtained in the simulations, including the structural densities of the beds, the characteristic lines, and the particle terminal velocity, are in good agreement with the experimental observations in the literature. To the authors' knowledge, this is the first time that the influences of non-dimensional Bond number and particle polydispersity on the structural densities of silt beds have been investigated separately

  15. Signaling Elaboration: Combining French Gerund Clauses with Lexical Cohesion Cues

    Directory of Open Access Journals (Sweden)

    Marianne Vergez-Couret

    2012-07-01

    Full Text Available In this paper, we focus on the Elaboration relation and on its automatic identification in French, using the theoretical framework of Segmented Discourse Representation Theory (SDRT. One of the information sources identified by the SDRT framework to infer the Elaboration relation is based on the existence of a potential subsumption link between the eventualities at stake, depending on lexical semantics and world knowledge. We investigate this claim by combining a weak syntactic marker of the Elaboration relation, namely the gerund clause, with lexical cohesion cues. We aim at automatically identifying gerund clauses which are Elaborations by finding cohesive links between the host main clause and the gerund clause. This approach makes it possible to accurately detect few cases of intra-sentential Elaborations in our corpus, confirming the fact that lexical cohesion cues are relevant for this task.Dans cet article, nous nous focalisons sur la relation d’Élaboration en français, telle qu’elle est décrite dans le modèle théorique de la SDRT (Segmented Discourse Representation Theory, et sur son identification automatique. Selon la SDRT, une des sources d’information permettant d’inférer la relation d’Élaboration est basée sur l’existence d’un lien de subsomption entre les types des éventualités des segments à relier, indiquant que le type de la seconde éventualité est un sous-type de celui de la première dans la sémantique lexicale des éventualités ou grâce à des connaissances du monde. Nous proposons de contribuer à cette question en combinant un indice de la relation d’Élaboration, i. e. la construction syntaxique du gérondif, et des indices de cohésion lexicale. Notre objectif est d’identifier automatiquement des propositions gérondives qui sont des Élaborations en repérant des indices de cohésion lexicale entre la proposition principale et la proposition gérondive. Cette approche permet de d

  16. Characterizing the influence of stress-induced microcracks on the laboratory strength and fracture development in brittle rocks using a finite-discrete element method-micro discrete fracture network FDEM-μDFN approach

    Directory of Open Access Journals (Sweden)

    Pooya Hamdi

    2015-12-01

    Full Text Available Heterogeneity is an inherent component of rock and may be present in different forms including mineral heterogeneity, geometrical heterogeneity, weak grain boundaries and micro-defects. Microcracks are usually observed in crystalline rocks in two forms: natural and stress-induced; the amount of stress-induced microcracking increases with depth and in-situ stress. Laboratory results indicate that the physical properties of rocks such as strength, deformability, P-wave velocity and permeability are influenced by increase in microcrack intensity. In this study, the finite-discrete element method (FDEM is used to model microcrack heterogeneity by introducing into a model sample sets of microcracks using the proposed micro discrete fracture network (μDFN approach. The characteristics of the microcracks required to create μDFN models are obtained through image analyses of thin sections of Lac du Bonnet granite adopted from published literature. A suite of two-dimensional laboratory tests including uniaxial, triaxial compression and Brazilian tests is simulated and the results are compared with laboratory data. The FDEM-μDFN models indicate that micro-heterogeneity has a profound influence on both the mechanical behavior and resultant fracture pattern. An increase in the microcrack intensity leads to a reduction in the strength of the sample and changes the character of the rock strength envelope. Spalling and axial splitting dominate the failure mode at low confinement while shear failure is the dominant failure mode at high confinement. Numerical results from simulated compression tests show that microcracking reduces the cohesive component of strength alone, and the frictional strength component remains unaffected. Results from simulated Brazilian tests show that the tensile strength is influenced by the presence of microcracks, with a reduction in tensile strength as microcrack intensity increases. The importance of microcrack heterogeneity in

  17. The effect of coarse gravel on cohesive sediment entrapment in an annular flume

    Science.gov (United States)

    Glasbergen, K.; Stone, M.; Krishnappan, B.; Dixon, J.; Silins, U.

    2015-03-01

    While cohesive sediment generally represents a small fraction (armour layer of the gravel bed (>16 Pa), cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

  18. "Sticking Together": The Adolescent Experience of the Cohesion Process in Rural School Counseling Groups

    Science.gov (United States)

    Gray, Tara M.; Rubel, Deborah

    2018-01-01

    The purpose of this study was to develop a grounded theory of how adolescents experience the cohesion process in rural school counseling groups. A total of 20 individual interviews with 7 participants were conducted. Data analysis generated the central category of the cohesion process as "sticking together," which describes a "tight…

  19. Cohesive subgroup formation : enabling and constraining effects of social capital in strategic technology alliance networks

    NARCIS (Netherlands)

    Duysters, G.M.; Lemmens, C.E.A.V.

    2002-01-01

    In this paper we will examine the role of embeddedness and social capital in the process of cohesive subgroup formation in strategic technology alliance networks. More in particular, we will investigate the social mechanisms that enable and enforce cohesive subgroup formation. We will argue that the

  20. Cohesion and Trauma: An Examination of a Collegiate Women's Volleyball Team

    Science.gov (United States)

    Fletcher, Teresa B.; Meyer, Barbara B.

    2009-01-01

    This study examined the effects of Adventure Based Counseling (i.e., a low-element challenge program) on the cohesion of a collegiate women's volleyball team. Results suggest postintervention improvements in team cohesion. The support created in the challenge experience also transferred to the players helping one another to grieve the untimely…

  1. Social Capital or Social Cohesion: What Matters for Subjective Well-Being?

    Science.gov (United States)

    Klein, Carlo

    2013-01-01

    The theoretical analysis of the concepts of social capital and of social cohesion shows that social capital should be considered as a micro concept whereas social cohesion, being a broader concept than social capital, is a more appropriate concept for macro analysis. Therefore, we suggest that data on the individual level should only be used to…

  2. Fatigue damage modeling in solder interconnects using a cohesive zone approach

    NARCIS (Netherlands)

    Abdul-Baqi, A.J.J.; Schreurs, P.J.G.; Geers, M.G.D.

    2005-01-01

    The objective of this work is to model the fatigue damage process in a solder bump subjected to cyclic loading conditions. Fatigue damage is simulated using the cohesive zone methodology. Damage is assumed to occur at interfaces modeled through cohesive zones in the material, while the bulk material

  3. Family Cohesion in the Lives of Mexican American and European American Parents

    Science.gov (United States)

    Behnke, Andrew O.; MacDermid, Shelley M.; Coltrane, Scott L.; Parke, Ross D.; Duffy, Sharon; Widaman, Keith F.

    2008-01-01

    This study investigated similarities and differences in relations between stress and parenting behaviors for 509 Mexican American and European American fathers and mothers in Southern California. Our model posited that family cohesion mediates the relation between stressors and parenting behavior, and we found that family cohesion strongly…

  4. The effect of coarse gravel on cohesive sediment entrapment in an annular flume

    Directory of Open Access Journals (Sweden)

    K. Glasbergen

    2015-03-01

    Full Text Available While cohesive sediment generally represents a small fraction (16 Pa, cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

  5. Cohesion Features in ESL Reading: Comparing Beginning, Intermediate and Advanced Textbooks

    Science.gov (United States)

    Plakans, Lia; Bilki, Zeynep

    2016-01-01

    This study of English as a second language (ESL) reading textbooks investigates cohesion in reading passages from 27 textbooks. The guiding research questions were whether and how cohesion differs across textbooks written for beginning, intermediate, and advanced second language readers. Using a computational tool called Coh-Metrix, textual…

  6. Influence of Sport Education on Group Cohesion in University Physical Education

    Science.gov (United States)

    Jenkins, Jayne M.; Alderman, Brandon L.

    2011-01-01

    The Sport Education ("SE") curricular model incorporated within university physical education Basic Instruction Program (BIP) may increase group cohesion. This study's purpose was to identify student perceptions of a BIP course taught within "SE," and investigate group cohesion in differing activity content. Participants…

  7. Performance auditing in EU cohesion policy: what do we know and what should we know?

    NARCIS (Netherlands)

    Damen, M.; Groenendijk, Nico

    2012-01-01

    Recently, the European Commission has put forward proposals for the next program period of EU Cohesion Policy (EUCP). Part of these proposals is an increased emphasis on performance management. This paper analyses what we know so far on performance management of EU cohesion funds. It will be argued

  8. Social cohesiveness and absenteeism: The relationship between characteristics of employees and short-term absenteeism

    NARCIS (Netherlands)

    Sanders, Karin; Nauta, Aukje

    2004-01-01

    This study tries to explain the relationship between characteristics of the employees (e.g., gender and working hours) and short-term absenteeism by examining the social cohesiveness of a team. Hypotheses are formulated concerning gender and working hours of employees, social cohesiveness, and

  9. Interparental Conflict and Family Cohesion: Predictors of Loneliness, Social Anxiety, and Social Avoidance in Late Adolescence.

    Science.gov (United States)

    Johnson, H. Durell; LaVoie, Joseph C.; Mahoney, Molly

    2001-01-01

    Examined relationship of family cohesion and interparental conflict with loneliness in 124 late adolescents. Found that feelings of loneliness were related to perceived levels of interparental conflict for males and females, and to decreased family cohesion for females. Feelings of social anxiety and social avoidance were related to feelings of…

  10. How to deal with legal uncertainty: Managing and Audit Authorities in Cohesion Policy

    NARCIS (Netherlands)

    Meuleman, Lysette; Brenninkmeijer, A.F.M.

    2017-01-01

    Cohesion policy (ERDF, ESF and CF) is implemented in a system of shared management. Signals received from some EU countries indicate that legal uncertainty is created for beneficiaries of cohesion policy funds due to differences in interpretation of, mostly national, regulation. This is a problem

  11. Social network cohesion in school classes promotes prosocial behavior.

    Science.gov (United States)

    van den Bos, Wouter; Crone, Eveline A; Meuwese, Rosa; Güroğlu, Berna

    2018-01-01

    Adolescence is a key period of social development at the end of which individuals are expected to take on adult social roles. The school class, as the most salient peer group, becomes the prime environment that impacts social development during adolescence. Using social network analyses, we investigated how individual and group level features are related to prosocial behavior and social capital (generalized trust). We mapped the social networks within 22 classrooms of adolescents aged between 12 and 18 years (N = 611), and collected data on social behaviors towards peers. Our results indicate that individuals with high centrality show both higher levels of prosocial behavior and relational aggression. Importantly, greater social cohesion in the classroom was associated with (1) reduced levels of antisocial behavior towards peers and (2) increased generalized trust. These results provide novel insights in the relationship between social structure and social behavior, and stress the importance of the school environment in the development of not only intellectual but also social capital.

  12. Cohesion energy calculations for ternary ionic novel crystals

    International Nuclear Information System (INIS)

    Vazquez P, G.; Cabrera, E.; Mijangos, R.R.; Valdez, E.; Duarte, C.

    2001-01-01

    The present work calculates the value of the link energy of a crystalline ternary structure newly formed by alkali halides. The ternary structure prepared with different concentrations of KCl x KBrRbCl 2 maintains a very good miscibility and stability. The calculation is based on the use of a generalization of the Vegard law (which generally is valid for binary compounds) for calculating the values of the lattice constant and the repulsive m exponent. The value of the lattice parameter given by X-ray diffractometry agrees with the close approximation of the calculated value of the method used. It also compares the value of energy cohesion obtained by the Born expression with more complex approximations. (Author)

  13. Stress-compatible embedded cohesive crack in CST element

    DEFF Research Database (Denmark)

    Olesen, John Forbes; Poulsen, Peter Noe

    2010-01-01

    A simple element with an embedded strong discontinuity for modeling cohesive cracking of concrete is presented. The element differs from previous elements of the embedded type, in that a consistent stress field is obtained by direct enforcement of stress continuity across the crack....... The displacement discontinuity is modeled in an XFEM fashion; however, the discontinuous displacement field is special, allowing for the direct enforcement of stress continuity. This in turn allows for elimination of extra degrees of freedom necessary for describing the crack deformations, thus the element has...... the same number of freedoms as its continuous basis: CST. The good performance of the element is demonstrated by its ability to simulate threepoint bending of a notched concrete beam. The advantage of the element is its simplicity and the straightforward implementation of it. Handling situations...

  14. Mechanisms of de cohesion in cutting aluminium matrix composites

    International Nuclear Information System (INIS)

    Cichosz, Piotr; Karolczak, Pawel; Kuzinovski, Mikolaj

    2008-01-01

    In this paper properties and applications of aluminium matrix composites are presented with a composite reinforced with saffil fibres selected for topical study. Behavior of matrix and reinforcement during machining with a cutting tool is analyzed. The paper presents an explosive quick-stop device designed to obtain undisturbed machined surface for examination. Meso hardness measurements of deformed structure, resultant chips and built-up-edge were carried out. Scanning micrographs of machined surface are presented with morphology and types of chips analysed. Values of the fibrousness angle ψ and thickening index k h of chip are evaluated. The research performed has enabled the authors to define mechanisms of e cohesion during cutting aluminium matrix composites. The results received for composite material are compared with those pertinent to aluminum alloys.

  15. The Cohesiveness of Muslim Pangestu Members in Salatiga, Central Java

    Directory of Open Access Journals (Sweden)

    S. Suciati

    2015-04-01

    Full Text Available The drying of spirituality and weakening of cohesiveness in the midst of materialistic hedonistic modern world become major challenge for the adherents of official religions in Indonesia. The practice of religions is considered too much focusing on ritual aspects. Therefore, those teachings cannot give the real meaningfulness of religious life. Consequently, some adherents of official religions begin to see other spiritual/mysticism sects. This study describes the social cohesiveness among muslims who become members of Pangestu, a spiritual-mysticism sect widely spreading among Javanese society in Indonesia. This research shows that the Pangestu in Salatiga, Central Java, can fulfill social, economic, and spiritual needs of its members. Among the underlying factors that make Pangestu succeed to meet its members’ needs and expectations are the capability of the members to intensely communicate with each other through meetings and bawaraos (Jv, informal gathering, the great concern between members, good-example of leadership, the defense of Pangestu’s good name, and the satisfaction in experiencing meaningfulness of religious practices.[Kekeringan spiritual dan lemahnya kebersamaan di tengah dunia modern yang serba hedonistik menjadi tantangan utama bagi para pemeluk agama di Indonesia. Praktik-praktik keagamaan terlalu banyak terfokus pada aspek ritual, sehingga ajaran agama tidak mampu menghadirkan praktek-praktek keagamaan yang benar-benar bermakna. Hal ini mendorong sebagian pemeluk agama untuk melirik aliran kepercayaan dan kebatinan. Artikel ini mendeskripsikan keguyuban sosial di antara orang-orang Islam yang menjadi anggota Pangestu, sebuah aliran kepercayaan di Indonesia yang banyak menyebar terutama di kalangan masyarakat Jawa. Penelitian ini menunjukkan bahwa Pangestu di Salatiga, Jawa Tegah, mampu memenuhi kebutuhan sosial, ekonomi, dan spiritual para anggotanya. Di antara faktor yang menentukan keberhasilan Pangestu dalam memenuhi

  16. Political State Boundary (National)

    Data.gov (United States)

    Department of Transportation — State boundaries with political limit - boundaries extending into the ocean (NTAD). The TIGER/Line Files are shapefiles and related database files (.dbf) that are an...

  17. Allegheny County Municipal Boundaries

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset demarcates the municipal boundaries in Allegheny County. Data was created to portray the boundaries of the 130 Municipalities in Allegheny County the...

  18. HUD GIS Boundary Files

    Data.gov (United States)

    Department of Housing and Urban Development — The HUD GIS Boundary Files are intended to supplement boundary files available from the U.S. Census Bureau. The files are for community planners interested in...

  19. State Agency Administrative Boundaries

    Data.gov (United States)

    Kansas Data Access and Support Center — This database comprises 28 State agency boundaries and point of contact. The Kansas Geological Survey collected legal descriptions of the boundaries for various...

  20. An Investigation into the Use of Cohesive Devises in Iranian High School EFL Textbooks

    Directory of Open Access Journals (Sweden)

    Mansour Shabani

    2015-07-01

    Full Text Available The present study aimed at probing into the use of grammatical and lexical cohesive subdevices in Iranian high school EFL textbooks. To this end, the reading sections of three high school EFL textbooks and one pre-university EFL textbook were analyzed in terms of the distribution of grammatical and lexical cohesive subdevices. The results of One-way ANOVA illustrated that: athere are no significant differences among the frequencies of grammatical cohesive subdevices across grade 1 high school EFL textbook and the pre-university EFL textbook, bthere are significant differences among the frequencies of grammatical cohesive subdevices across grades 2 and 3 high school EFL textbooks. Moreover, the results of Chi-Square test showed that the significant values of all of the lexical cohesive subdevices were higher than .05 across each of the Iranian EFL high school textbooks. These findings can be beneficial for textbook writers, materials developers and EFL teachers.

  1. Mode I Cohesive Law Characterization of Through-Crack Propagation in a Multidirectional Laminate

    Science.gov (United States)

    Bergan, Andrew C.; Davila, Carlos G.; Leone, Frank A.; Awerbuch, Jonathan; Tan, Tein-Min

    2014-01-01

    A method is proposed and assessed for the experimental characterization of through-the-thickness crack propagation in multidirectional composite laminates with a cohesive law. The fracture toughness and crack opening displacement are measured and used to determine a cohesive law. Two methods of computing fracture toughness are assessed and compared. While previously proposed cohesive characterizations based on the R-curve exhibit size effects, the proposed approach results in a cohesive law that is a material property. The compact tension specimen configuration is used to propagate damage while load and full-field displacements are recorded. These measurements are used to compute the fracture toughness and crack opening displacement from which the cohesive law is characterized. The experimental results show that a steady-state fracture toughness is not reached. However, the proposed method extrapolates to steady-state and is demonstrated capable of predicting the structural behavior of geometrically-scaled specimens.

  2. Bedform development and morphodynamics in mixed cohesive sediment substrates: the importance of winnowing and flocculation

    Science.gov (United States)

    Ye, Leiping; Parsons, Daniel; Manning, Andrew

    2016-04-01

    There remains a lack of process-based knowledge of sediment dynamics within flows over bedforms generated in complex mixtures of cohesionless sand and biologically-active cohesive muds in natural estuarine flow systems. The work to be presented forms a part of the UK NERC "COHesive BEDforms (COHBED)" project which aims to fill this gap in knowledge. Herein results from a field survey in sub-tidal zone of Dee estuary (NW, England) and a set of large-scale laboratory experiments, conducted using mixtures of non-cohesive sands, cohesive muds and Xanthan gum (as a proxy for the biological stickiness of Extracellular Polymeric Substances (EPS)) will be presented. The results indicate the significance of biological-active cohesive sediments in controlling winnowing rates and flocculation dynamics, which contributes significantly to rates of bedform evolution.

  3. Sex differences in the development of perceived family cohesion and depressive symptoms in Taiwanese adolescents.

    Science.gov (United States)

    Sze, Tat-Ming; Hsieh, Pei-Jung; Lin, Sieh-Hwa; Chen, I-Jung

    2013-08-01

    This study investigates the progression of family cohesion perceptions and depressive symptoms during the character development stage in adolescents. Data were used from the Taiwan Youth Project. The final sample comprised 2,690 adolescents with 1,312 girls (48.8%; M age = 13.0 yr., SD = 0.5). Latent curve growth analysis was employed to explore these developments. Seventh-grade girls reported greater family cohesion and more depressive symptoms than boys, and boys reported greater growth in family cohesion than girls. However, progression of depressive symptoms was not associated with the child's sex. Higher perceived family cohesion in Grade 7 correlated with less increase of depressive symptoms from Grades 9 to 11. The long-term positive influence of family cohesion on depressive symptoms is discussed.

  4. A Process and Environment Aware Sierra/SolidMechanics Cohesive Zone Modeling Capability for Polymer/Solid Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, E. D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Chambers, Robert S. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Hughes, Lindsey Gloe [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Kropka, Jamie Michael [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Stevens, Mark J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    The performance and reliability of many mechanical and electrical components depend on the integrity of po lymer - to - solid interfaces . Such interfaces are found in adhesively bonded joints, encapsulated or underfilled electronic modules, protective coatings, and laminates. The work described herein was aimed at improving Sandia's finite element - based capability to predict interfacial crack growth by 1) using a high fidelity nonlinear viscoelastic material model for the adhesive in fracture simulations, and 2) developing and implementing a novel cohesive zone fracture model that generates a mode - mixity dependent toughness as a natural consequence of its formulation (i.e., generates the observed increase in interfacial toughness wi th increasing crack - tip interfacial shear). Furthermore, molecular dynamics simulations were used to study fundamental material/interfa cial physics so as to develop a fuller understanding of the connection between molecular structure and failure . Also reported are test results that quantify how joint strength and interfacial toughness vary with temperature.

  5. Relationship between the cohesion of guest particles on the flow behaviour of interactive mixtures.

    Science.gov (United States)

    Mangal, Sharad; Gengenbach, Thomas; Millington-Smith, Doug; Armstrong, Brian; Morton, David A V; Larson, Ian

    2016-05-01

    In this study, we aimed to investigate the effects cohesion of small surface-engineered guest binder particles on the flow behaviour of interactive mixtures. Polyvinylpyrrolidone (PVP) - a model pharmaceutical binder - was spray-dried with varying l-leucine feed concentrations to create small surface-engineered binder particles with varying cohesion. These spray-dried formulations were characterised by their particle size distribution, morphology and cohesion. Interactive mixtures were produced by blending these spray-dried formulations with paracetamol. The resultant blends were visualised under scanning electron microscope to confirm formation of interactive mixtures. Surface coverage of paracetamol by guest particles as well as the flow behaviour of these mixtures were examined. The flow performance of interactive mixtures was evaluated using measurements of conditioned bulk density, basic flowability energy, aeration energy and compressibility. With higher feed l-leucine concentrations, the surface roughness of small binder particles increased, while their cohesion decreased. Visual inspection of the SEM images of the blends indicated that the guest particles adhered to the surface of paracetamol resulting in effective formation of interactive mixtures. These images also showed that the low-cohesion guest particles were better de-agglomerated that consequently formed a more homogeneous interactive mixture with paracetamol compared with high-cohesion formulations. The flow performance of interactive mixtures changed as a function of the cohesion of the guest particles. Interactive mixtures with low-cohesion guest binder particles showed notably improved bulk flow performance compared with those containing high-cohesion guest binder particles. Thus, our study suggests that the cohesion of guest particles dictates the flow performance of interactive mixtures. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  6. On boundary superalgebras

    International Nuclear Information System (INIS)

    Doikou, Anastasia

    2010-01-01

    We examine the symmetry breaking of superalgebras due to the presence of appropriate integrable boundary conditions. We investigate the boundary breaking symmetry associated with both reflection algebras and twisted super-Yangians. We extract the generators of the resulting boundary symmetry as well as we provide explicit expressions of the associated Casimir operators.

  7. Ground observations of magnetospheric boundary layer phenomena

    International Nuclear Information System (INIS)

    McHenry, M.A.; Clauer, C.R.; Friis-Christensen, E.; Newell, P.T.; Kelly, J.D.

    1990-01-01

    Several classes of traveling vortices in the dayside ionospheric convection have been detected and tracked using the Greenland magnetometer chain (Friis-Christensen et al., 1988, McHenry et al., 1989). One class observed during quiet times consists of a continuous series of vortices moving generally anti-sunward for several hours at a time. The vortices strength is seen to be approximately steady and neighboring vortices rotate in opposite directions. Sondrestrom radar observations show that the vortices are located at the ionospheric convection reversal boundary. Low altitude DMSP observations indicate the vortices are on field lines which map to the inner edge of the low latitude boundary layer. Because the vortices are conjugate to the boundary layer, repeat in a regular fashion and travel antisunward, the authors argue that this class of vortices is caused by the Kelvin-Helmholtz instability of the inner edge of the magnetospheric boundary layer

  8. Method and apparatus for blending fine and cohesive powders in a fluidized bed with gas injection through ball valves

    International Nuclear Information System (INIS)

    1981-01-01

    A fluidized bed blender is described, suitable for blending powders including a mixture of fine and cohesive powders and in particular for converting a heterogeneous mixture of fine and cohesive UO 2 into a homogeneous mixture. (U.K.)

  9. Effect of grain boundary structures on the behavior of He defects in Ni: An atomistic study

    Institute of Scientific and Technical Information of China (English)

    H F Gong; Y Yan; X S Zhang; W Lv; T Liu; Q S Ren

    2017-01-01

    We investigated the effect of grain boundary structures on the trapping strength of HeN (N is the number of helium atoms) defects in the grain boundaries of nickel.The results suggest that the binding energy of an interstitial helium atom to the grain boundary plane is the strongest among all sites around the plane.The HeN defect is much more stable in nickel bulk than in the grain boundary plane.Besides,the binding energy of an interstitial helium atom to a vacancy is stronger than that to a grain boundary plane.The binding strength between the grain boundary and the HeN defect increases with the defect size.Moreover,the binding strength of the HeN defect to the Σ3 (1 12)[110] grain boundary becomes much weaker than that to other grain boundaries as the defect size increases.

  10. Sister chromatid cohesion defects are associated with chromosome instability in Hodgkin lymphoma cells

    International Nuclear Information System (INIS)

    Sajesh, Babu V; Lichtensztejn, Zelda; McManus, Kirk J

    2013-01-01

    Chromosome instability manifests as an abnormal chromosome complement and is a pathogenic event in cancer. Although a correlation between abnormal chromosome numbers and cancer exist, the underlying mechanisms that cause chromosome instability are poorly understood. Recent data suggests that aberrant sister chromatid cohesion causes chromosome instability and thus contributes to the development of cancer. Cohesion normally functions by tethering nascently synthesized chromatids together to prevent premature segregation and thus chromosome instability. Although the prevalence of aberrant cohesion has been reported for some solid tumors, its prevalence within liquid tumors is unknown. Consequently, the current study was undertaken to evaluate aberrant cohesion within Hodgkin lymphoma, a lymphoid malignancy that frequently exhibits chromosome instability. Using established cytogenetic techniques, the prevalence of chromosome instability and aberrant cohesion was examined within mitotic spreads generated from five commonly employed Hodgkin lymphoma cell lines (L-1236, KM-H2, L-428, L-540 and HDLM-2) and a lymphocyte control. Indirect immunofluorescence and Western blot analyses were performed to evaluate the localization and expression of six critical proteins involved in the regulation of sister chromatid cohesion. We first confirmed that all five Hodgkin lymphoma cell lines exhibited chromosome instability relative to the lymphocyte control. We then determined that each Hodgkin lymphoma cell line exhibited cohesion defects that were subsequently classified into mild, moderate or severe categories. Surprisingly, ~50% of the mitotic spreads generated from L-540 and HDLM-2 harbored cohesion defects. To gain mechanistic insight into the underlying cause of the aberrant cohesion we examined the localization and expression of six critical proteins involved in cohesion. Although all proteins produced the expected nuclear localization pattern, striking differences in RAD21

  11. Avalanche weak layer shear fracture parameters from the cohesive crack model

    Science.gov (United States)

    McClung, David

    2014-05-01

    Dry slab avalanches release by mode II shear fracture within thin weak layers under cohesive snow slabs. The important fracture parameters include: nominal shear strength, mode II fracture toughness and mode II fracture energy. Alpine snow is not an elastic material unless the rate of deformation is very high. For natural avalanche release, it would not be possible that the fracture parameters can be considered as from classical fracture mechanics from an elastic framework. The strong rate dependence of alpine snow implies that it is a quasi-brittle material (Bažant et al., 2003) with an important size effect on nominal shear strength. Further, the rate of deformation for release of an avalanche is unknown, so it is not possible to calculate the fracture parameters for avalanche release from any model which requires the effective elastic modulus. The cohesive crack model does not require the modulus to be known to estimate the fracture energy. In this paper, the cohesive crack model was used to calculate the mode II fracture energy as a function of a brittleness number and nominal shear strength values calculated from slab avalanche fracture line data (60 with natural triggers; 191 with a mix of triggers). The brittleness number models the ratio of the approximate peak value of shear strength to nominal shear strength. A high brittleness number (> 10) represents large size relative to fracture process zone (FPZ) size and the implications of LEFM (Linear Elastic Fracture Mechanics). A low brittleness number (e.g. 0.1) represents small sample size and primarily plastic response. An intermediate value (e.g. 5) implies non-linear fracture mechanics with intermediate relative size. The calculations also implied effective values for the modulus and the critical shear fracture toughness as functions of the brittleness number. The results showed that the effective mode II fracture energy may vary by two orders of magnitude for alpine snow with median values ranging from 0

  12. [Bond strengths of absorbable polylactic acid root canal post with three different adhesives].

    Science.gov (United States)

    Pan, Hui; Cheng, Can; Hu, Jia; Liu, He; Sun, Zhi-hui

    2015-12-18

    To find absorbable adhesives with suitable bonding properties for the absorbable polylactic acid root canal post. To test and compare the bond strengths of absorbable polylactic acid root canal post with three different adhesives. The absorbable polylactic acid root canal posts were used to restore the extracted teeth, using 3 different adhesives: cyanoacrylates, fibrin sealant and glass ionomer cement. The teeth were prepared into slices for micro-push-out test. The bond strength was statistically analyzed using ANOVA. The specimens were examined using microscope and the failure mode was divided into four categories: cohesive failure between absorbable polylactic acid root canal posts and adhesives, cohesive failure between dentin and adhesives, failure within the adhesives and failure within the absorbable polylactic acid root canal posts. The bond strength of cyanoacrylates [(16.83 ± 6.97) MPa] and glass ionomer cement [(12.10 ± 5.09) MPa] were significantly higher than fibrin sealant [(1.17 ± 0.50) MPa], Padhesives was 25.0%, the cohesive failure between the dentin and the adhesives was 16.7%, the failure within the adhesives was 33.3%, and the failure within the absorbable polylactic acid root canal posts was 25.0%. In the group of fibrin sealant, the cohesive failure between the absorbable polylactic acid root canal posts and the adhesives was 66.7%, the cohesive failure between the dentin and the adhesives was 22.2%, the failure within the adhesives was 11.1%. In the group of glass ionomer cement, the cohesive failure between the absorbable polylactic acid root canal posts and the adhesives was 87.5%, the failure within the adhesives was 12.5%. The major failure mode in fibrin sealant and glass ionomer cement was the cohesive failure between the absorbable polylactic acid root canal posts and the adhesives. No major failure modes were found in the group of cyanoacrylates. The bond strength of fibrin sealant is low, which cannot meet the requirement of

  13. Parameter estimation for a cohesive sediment transport model by assimilating satellite observations in the Hangzhou Bay: Temporal variations and spatial distributions

    Science.gov (United States)

    Wang, Daosheng; Zhang, Jicai; He, Xianqiang; Chu, Dongdong; Lv, Xianqing; Wang, Ya Ping; Yang, Yang; Fan, Daidu; Gao, Shu

    2018-01-01

    Model parameters in the suspended cohesive sediment transport models are critical for the accurate simulation of suspended sediment concentrations (SSCs). Difficulties in estimating the model parameters still prevent numerical modeling of the sediment transport from achieving a high level of predictability. Based on a three-dimensional cohesive sediment transport model and its adjoint model, the satellite remote sensing data of SSCs during both spring tide and neap tide, retrieved from Geostationary Ocean Color Imager (GOCI), are assimilated to synchronously estimate four spatially and temporally varying parameters in the Hangzhou Bay in China, including settling velocity, resuspension rate, inflow open boundary conditions and initial conditions. After data assimilation, the model performance is significantly improved. Through several sensitivity experiments, the spatial and temporal variation tendencies of the estimated model parameters are verified to be robust and not affected by model settings. The pattern for the variations of the estimated parameters is analyzed and summarized. The temporal variations and spatial distributions of the estimated settling velocity are negatively correlated with current speed, which can be explained using the combination of flocculation process and Stokes' law. The temporal variations and spatial distributions of the estimated resuspension rate are also negatively correlated with current speed, which are related to the grain size of the seabed sediments under different current velocities. Besides, the estimated inflow open boundary conditions reach the local maximum values near the low water slack conditions and the estimated initial conditions are negatively correlated with water depth, which is consistent with the general understanding. The relationships between the estimated parameters and the hydrodynamic fields can be suggestive for improving the parameterization in cohesive sediment transport models.

  14. The Strength Compass

    DEFF Research Database (Denmark)

    Ledertoug, Mette Marie

    In the Ph.D-project ͚Strengths-based Learning - Children͛s character strengths as a means to their learning potential͛ 750 Danish children have assessed ͚The Strength Compass͛ in order to identify their strengths and to create awareness of strengths. This was followed by a strengths......-based intervention program in order to explore the strengths. Finally different methods to apply the strength in everyday life at school were applied. The paper presentation will show the results for strengths display for children aged 6-16 in different categories: Different age groups: Are the same strengths...... present in both small children and youths? Gender: Do the results show differences between the two genders? Danish as a mother- tongue language: Do the results show any differences in the strengths display when considering different language and cultural backgrounds? Children with Special Needs: Do...

  15. Flow Function of Pharmaceutical Powders Is Predominantly Governed by Cohesion, Not by Friction Coefficients.

    Science.gov (United States)

    Leung, Lap Yin; Mao, Chen; Srivastava, Ishan; Du, Ping; Yang, Chia-Yi

    2017-07-01

    The purpose of this study was to demonstrate that the flow function (FFc) of pharmaceutical powders, as measured by rotational shear cell, is predominantly governed by cohesion but not friction coefficients. Driven by an earlier report showing an inverse correlation between FFc and the cohesion divided by the corresponding pre-consolidation stress (Wang et al. 2016. Powder Tech. 294:105-112), we performed analysis on a large data set containing 1130 measurements from a ring shear tester and identified a near-perfect inverse correlation between the FFc and cohesion. Conversely, no correlation was found between FFc and friction angles. We also conducted theoretical analysis and estimated such correlations based on Mohr-Coulomb failure model. We discovered that the correlation between FFc and cohesion can sustain as long as the angle of internal friction at incipient flow is not significantly larger than the angle of internal friction at steady-state flow, a condition covering almost all pharmaceutical powders. The outcome of this study bears significance in pharmaceutical development. Because the cohesion value is strongly influenced by the interparticle cohesive forces, this study effectively shows that it is more efficient to improve the pharmaceutical powder flow by lowering the interparticle cohesive forces than by lowering the interparticle frictions. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  16. Development of low energy electron beam irradiation technology. Application to cohesive and adhesive agents

    International Nuclear Information System (INIS)

    Ito, Hisashi; Enomoto, Ichiro; Tsuchiya, Mitsuaki

    1996-01-01

    The hightening of the cohesive and adhesive performances of rubber cohesive and adhesive agents, of which the main component is electron beam-cross-linked styrene-isoprene block copolymer (SIS), was tried. Cohesive and adhesive agents are cohesive agents at the time of use, but change to adhesive property by the lapse of time or the means using heat, light or radiation, and further, partially to separating property. This time, as a cohesion-giving agent, ARKON P-100 system was examined, and the heightening of adhesive performance including the improvement of the heat resistance and solvent endurance, which are the demerits of rubber, was investigated. Also the difference of the cohesive and adhesive performances due to the kinds of cohesion-giving agents was examined. The samples were prepared by irradiating the films on which the SIS was applied. The measurement of gel proportion, the holding force test at elevated temperature, the measurement of DSC and 180deg separation test were carried out. Respective testing methods and the results are reported. By electron beam irradiation, the heat resistance and solvent endurance were improved without affecting the separation force. (K.I.)

  17. Effect of cohesion on local compaction and granulation of sheared soft granular materials

    Directory of Open Access Journals (Sweden)

    Roy Sudeshna

    2017-01-01

    Full Text Available This paper results from an ongoing investigation of the effect of cohesion on the compaction of sheared soft wet granular materials. We compare dry non-cohesive and wet moderately-to-strongly cohesive soft almost frictionless granular materials and report the effect of cohesion between the grains on the local volume fraction. We study this in a three dimensional, unconfined, slowly sheared split-bottom ring shear cell, where materials while sheared are subject to compression under the confining weight of the material above. Our results show that inter-particle cohesion has a considerable impact on the compaction of soft materials. Cohesion causes additional stresses, due to capillary forces between particles, leading to an increase in volume fraction due to higher compaction. This effect is not visible in a system of infinitely stiff particles. In addition, acting oppositely, we observe a general decrease in volume fraction due to increased cohesion for frictional particle, which we attribute to the role of contact friction that enhances dilation.

  18. Interrelations between Energy Security Economics and Social Cohesion: Analysis of a Lithuanian Case

    Directory of Open Access Journals (Sweden)

    Dainius Genys

    2015-12-01

    Full Text Available Growing attention to sustainable development in academic discourse fosters discussions on how energy security affects society. In most cases the discussions consider the political and economic consequences, which affect or may affect the society. The aim of the article is to assess the impact of energy security economics on social cohesion in Lithuania. To achieve this aim the interrelations between energy security, energy economics and social cohesion are discussed. The theoretical framework of social cohesion (introduced by J. Jenson and P. Bernard is presented and applied in empirical analysis. The operationalization of empirical variables is based on economic, political and socio-cultural - activity areas, which are analyzed to verify the dichotomies between public attitudes and the actual behavior of society. These dichotomies help to distinguish six analytical dimensions, on the basis of which we created 17 empirical indicators, which analysis allows for describing the impact of Lithuanian energy security economics on social cohesion in quantitative data. The statistical analyses showed that the impact of attitudinal dimensions of energy security economics on social cohesion in Lithuania has an almost neutral effect: 3.05 (1-very negative; 3-neutral, 5-very positive. Whereas, the impact of behavioural dimensions of energy security economics on social cohesion has a negative effect: 2.47. The aggregated average of the overall impact of energy security economics on social cohesion in Lithuania has a negative effect: 2.76.

  19. Cohesion, leadership, mental health stigmatisation and perceived barriers to care in UK military personnel.

    Science.gov (United States)

    Jones, Norman; Campion, Ben; Keeling, Mary; Greenberg, Neil

    2018-02-01

    Military research suggests a significant association between leadership, cohesion, mental health stigmatisation and perceived barriers to care (stigma/BTC). Most studies are cross sectional, therefore longitudinal data were used to examine the association of leadership and cohesion with stigma/BTC. Military personnel provided measures of leadership, cohesion, stigma/BTC, mental health awareness and willingness to discuss mental health following deployment (n = 2510) and 4-6 months later (n = 1636). At follow-up, baseline leadership and cohesion were significantly associated with stigma/BTC; baseline cohesion alone was significantly associated with awareness of and willingness to discuss mental health at follow-up. Over time, changes in perceived leadership and cohesion were significantly associated with corresponding changes in stigma/BTC levels. Stigma/BTC content was similar in both surveys; fear of being viewed as weak and being treated differently by leaders was most frequently endorsed while thinking less of a help-seeking team member and unawareness of potential help sources were least common. Effective leadership and cohesion building may help to reduce stigma/BTC in military personnel. Mental health awareness and promoting the discussion of mental health matters may represent core elements of supportive leader behaviour. Perceptions of weakness and fears of being treated differently represent a focus for stigma/BTC reduction.

  20. Family cohesion and posttraumatic intrusion and avoidance among war veterans: a 20-year longitudinal study.

    Science.gov (United States)

    Zerach, Gadi; Solomon, Zahava; Horesh, Danny; Ein-Dor, Tsachi

    2013-02-01

    The bi-directional relationships between combat-induced posttraumatic symptoms and family relations are yet to be understood. The present study assesses the longitudinal interrelationship of posttraumatic intrusion and avoidance and family cohesion among 208 Israeli combat veterans from the 1982 Lebanon War. Two groups of veterans were assessed with self-report questionnaires 1, 3 and 20 years after the war: a combat stress reaction (CSR) group and a matched non-CSR control group. Latent Trajectories Modeling showed that veterans of the CSR group reported higher intrusion and avoidance than non-CSR veterans at all three points of time. With time, there was a decline in these symptoms in both groups, but the decline was more salient among the CSR group. The latter also reported lower levels of family cohesion. Furthermore, an incline in family cohesion levels was found in both groups over the years. Most importantly, Autoregressive Cross-Lagged Modeling among CSR and non-CSR veterans revealed that CSR veterans' posttraumatic symptoms in 1983 predicted lower family cohesion in 1985, and lower family cohesion, in turn, predicted posttraumatic symptoms in 2002. The findings suggest that psychological breakdown on the battlefield is a marker for future family cohesion difficulties. Our results lend further support for the bi-directional mutual effects of posttraumatic symptoms and family cohesion over time.

  1. Mind the gap! Automated concept map feedback supports students in writing cohesive explanations.

    Science.gov (United States)

    Lachner, Andreas; Burkhart, Christian; Nückles, Matthias

    2017-03-01

    Many students are challenged with the demand of writing cohesive explanations. To support students in writing cohesive explanations, we developed a computer-based feedback tool that visualizes cohesion deficits of students' explanations in a concept map. We conducted three studies to investigate the effectiveness of such feedback as well as the underlying cognitive processes. In Study 1, we found that the concept map helped students identify potential cohesion gaps in their drafts and plan remedial revisions. In Study 2, students with concept map feedback conducted revisions that resulted in more locally and globally cohesive, and also more comprehensible, explanations than the explanations of students who revised without concept map feedback. In Study 3, we replicated the findings of Study 2 by and large. More importantly, students who had received concept map feedback on a training explanation 1 week later wrote a transfer explanation without feedback that was more cohesive than the explanation of students who had received no feedback on their training explanation. The automated concept map feedback appears to particularly support the evaluation phase of the revision process. Furthermore, the feedback enabled novice writers to acquire sustainable skills in writing cohesive explanations. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. [Effects of family cohesion and adaptability on behavioral problems in preschool children].

    Science.gov (United States)

    Wang, Yan-Ni; Xue, Hong-Li; Chen, Qian

    2016-05-01

    To investigate the effects of family cohesion and adaptability on behavioral problems in preschool children. The stratified cluster multistage sampling method was used to perform a questionnaire survey in the parents of 1 284 children aged 3-6 years in the urban area of Lanzhou, China. The general status questionnaire, Conners Child Behavior Checklist (Parent Symptom Question), and Family Adaptability and Cohesion Scale, Second edition, Chinese version (FACESII-CV) were used to investigate behavioral problems and family cohesion and adaptability. The overall detection rate of behavioral problems in preschool children was 17.13%. The children with different types of family cohesion had different detection rates of behavioral problems, and those with free-type family cohesion showed the highest detection rate of behavioral problems (40.2%). The children with different types of family adaptability also had different detection rates of behavioral problems, and those with stiffness type showed the highest detection rate of behavioral problems (25.1%). The behavioral problems in preschool children were negatively correlated with family cohesion and adaptability. During the growth of preschool children, family cohesion and adaptability have certain effects on the mental development of preschool children.

  3. Winnowing and Flocculation in Bio-physical Cohesive Substrate: A Flume Experimental and Estuarine Study

    Science.gov (United States)

    Ye, L.; Parsons, D. R.; Manning, A. J.

    2016-12-01

    Cohesive sediment, or mud, is ubiquitously found in most aqueous environments, such as coasts and estuaries. The study of cohesive sediment behaviors requires the synchronous description of mutual interactions of grains (e.g., winnowing and flocculation), their physical properties (e.g., grain size) and also the ambient water. Herein, a series of flume experiments (14 runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substrates: secreted by aquatic microorganisms) are combined with an estuarine field survey (Dee estuary, NW England) to investigate the behavior of suspensions over bio-physical cohesive substrates. The experimental results indicate that winnowing and flocculation occur pervasively in bio-physical cohesive flow systems. Importantly however, the evolution of the bed and bedform dynamics and hence turbulence production can be lower when cohesivity is high. The estuarine survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed, that pervasively exists in many natural estuarine systems, plays a significant role in controlling the interactions between bed substrate and sediment suspension and deposition, including controlling processes such as sediment winnowing, flocculation and re-deposition. Full understanding of these processes are essential in advancing sediment transport modelling and prediction studies across natural estuarine systems and the work will report on an improved conceptual model for sediment sorting deposition in bio-physical cohesive substrates.

  4. Channel Bank Cohesion and the Maintenance of Suspension Rivers

    Science.gov (United States)

    Dunne, K. B. J.; Jerolmack, D. J.

    2017-12-01

    Gravel-bedded rivers organize their channel geometry and grain size such that transport is close to the threshold of motion at bankfull. Sand-bedded rivers, however, typically maintain bankfull fluid shear (or Shields) stresses far in excess of threshold; there is no widely accepted explanation for these "suspension rivers". We propose that all alluvial rivers are at the threshold of motion for their erosion-limiting material, i.e., the structural component of the river cross-section that is most difficult to mobilize. The entrainment threshold of gravel is large enough that bank cohesion has little influence on gravel-bed rivers. Sand, however, is the most easily entrained material; silt and clay can raise the entrainment threshold of sand by orders of magnitude. We examine a global dataset of river channel geometry and show that the shear stress range for sand-bedded channels is entirely within the range of entrainment thresholds for sand-mud mixtures - suggesting that rivers that suspend their sandy bed material are still threshold rivers in terms of bank material. We then present new findings from a New Jersey coastal-plain river examining if and how river-bank toe composition controls hydraulic geometry. We consider the toe because it is the foundation of the river bank, and its erosion leads to channel widening. Along a 20-km profile of the river we measure cross-section geometry, bed slope, and bed and bank composition, and we explore multiple methods of measuring the threshold shear stress of the the river-bank toe in-situ. As the composition of the river bed transitions from gravel to sand, we see preliminary evidence of a shift from bed-threshold to bank-threshold control on hydraulic geometry. We also observe that sub-bankfull flows are insufficient to erode (cohesive) bank materials, even though transport of sand is active at nearly all flows. Our findings highlight the importance of focusing on river-bank toe material, which in the studied stream is

  5. Differences by Sexual Orientation in Perceptions of Neighborhood Cohesion: Implications for Health.

    Science.gov (United States)

    Henning-Smith, Carrie; Gonzales, Gilbert

    2018-06-01

    A large body of research documents the relationship between health and place, including the positive association between neighborhood cohesion and health. However, very little research has examined neighborhood cohesion by sexual orientation. This paper addresses that gap by examining differences in perceived neighborhood cohesion by sexual orientation. We use data from the 2016 National Health Interview Survey (n = 28,164 respondents aged 18 years and older) to examine bivariate differences by sexual orientation in four measures of neighborhood cohesion. We then use ordered logistic regression models to assess the relationship between sexual orientation and a scaled measure of neighborhood cohesion, adjusting for socio-demographic characteristics, living arrangements, health status, region, and neighborhood tenure. We find that lesbian, gay, and bisexual (LGB) adults are less likely to say that they live in a close-knit neighborhood (54.6 vs. 65.6%, p < 0.001), they can count on their neighbors (74.7 vs. 83.1%, p < 0.001), they trust their neighbors (75.5 vs. 83.7%, p < 0.001), or people in their neighborhood help each other out (72.9 vs. 83.1%, p < 0.001), compared to heterosexual adults. Even after controlling for socio-demographic factors, neighborhood cohesion scores are lower for LGB adults compared to heterosexual adults (odds ratio of better perceived neighborhood cohesion for sexual minorities: 0.70, p < 0.001). Overall, LGB adults report worse neighborhood cohesion across multiple measures, even after adjusting for individual characteristics and neighborhood tenure. Because living in a cohesive neighborhood is associated with better health outcomes, future research, community-level initiatives, and public policy efforts should focus on creating welcoming neighborhood environments for sexual minorities.

  6. Differences in neighborhood social cohesion and aerobic physical activity by Latino subgroup

    Directory of Open Access Journals (Sweden)

    Rosenda Murillo

    2016-12-01

    Full Text Available Previous research has examined the role of neighborhood social cohesion in physical activity outcomes; however, less is known about this relationship across Latino subgroups. The purpose of our study was to examine the association between neighborhood social cohesion and aerobic leisure-time physical activity (LTPA among Latino adults and to determine whether these associations differ by Latino subgroup. We used cross-sectional 2013–2014 National Health Interview Survey (NHIS data on Latinos originating from 5 countries/regions (i.e., Latinos of Puerto Rican, Mexican/Mexican-American, Cuban/Cuban-American, Dominican and Central or South American origin aged ≥18 years (n=11,126. Multivariable logistic regression models were used to estimate associations between self-reported neighborhood social cohesion and meeting aerobic LTPA guidelines. Models were adjusted for age, sex, education, and acculturation. We also investigated whether associations varied by Latino subgroup. In adjusted models for all Latino adults, compared with those reporting low social cohesion, individuals who reported high social cohesion (Odds Ratio [OR]: 1.33; 95% Confidence Interval [CI]: 1.17–1.52 were significantly more likely to meet the aerobic physical activity guideline. When stratified by Latino subgroups, among Mexican/Mexicans-Americans (OR: 1.39; 95% CI: 1.16, 1.66 and Cuban/Cuban Americans (OR: 1.73; 95% CI: 1.00, 2.97 high social cohesion was associated with meeting the aerobic activity guideline. Among Dominicans, those who reported medium social cohesion (OR: 0.52, 95% CI: 0.29, 0.93 were less likely to meet the aerobic activity guideline. When examining aerobic physical activity outcomes in the Latino population, the role of neighborhood social cohesion and the variability among Latino subgroups should be considered. Keywords: Neighborhood social cohesion, Physical activity, Latinos, subgroups

  7. Interdependence and organizational citizenship behavior: exploring the mediating effect of group cohesion in multilevel analysis.

    Science.gov (United States)

    Chen, Chun-Hsi Vivian; Tang, Ya-Yun; Wang, Shih-Jon

    2009-12-01

    The authors investigated the mechanism of group cohesion in the relationship between (a) task interdependence and goal interdependence and (b) individuals' organizational citizenship behavior (OCB). The authors adopted a multilevel perspective to facilitate understanding of the complex relations among variables. They collected data from 53 supervisors and 270 employees from R&D departments in Taiwan. The authors found that group cohesion fully mediated the effects of task interdependence and goal interdependence on employees' OCB. In addition, task interdependence had a greater effect on group cohesion than did goal interdependence. The authors discuss implications and suggestions for future research.

  8. Determination of diffusion coefficients in cohesive and sandy sediment from the area of Gorleben

    International Nuclear Information System (INIS)

    Klotz, D.

    1989-01-01

    The cohesive and sandy sediments stem from shaft driving at the Gorleben salt done. For the cohesive materials, HTD was used as a tracer substance, while I-131 - was used for the sandy materials. Diffusion coefficients of HTD in cohesive materials in their natural texture are in the range of 2x10 -6 to 5x10 -6 cm 2 /s, those of I-131 - in the investigated uniform fine and middle sands are approximately 3x10 -6 cm 2 /s. (DG) [de

  9. Boundary and sub-boundary hardening in tempered martensitic 9Cr steel during long-term creep at 650 C

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Fujio [National Institute for Materials Science, Sengen, Tsukuba (Japan)

    2010-07-01

    The boundary and sub-boundary hardening is shown to be the most important strengthening mechanism in creep of the 9% Cr steel base metal and welded joints. The addition of boron reduces the coarsening rate of M{sub 23}C{sub 6} carbides along boundaries near prior austenite grain boundaries during creep, enhancing the boundary and sub-boundary hardening. This improves long-term creep strength of base metal. The enhancement of boundary and sub-boundary hardening is significantly reduced in fine-grained region of Ac{sub 3} HAZ simulated specimens of conventional steel P92. In NIMS 9Cr boron steel welded joints, the grain size and distribution of carbonitrides are substantially the same between the HAZ and base metal, where fine carbonitrides are distributed along the lath and block boundaries as well as along prior austenite grain boundaries. This is essential for the suppression of Type IV fracture in NIMS 9% Cr boron steel welded joints. Newly alloy-designed 9Cr steel with 160 ppm boron and 85 ppm nitrogen exhibits much higher creep rupture strength of base metal than P92 and also no Tpe-IV fracture in welded joints at 650 C. (orig.)

  10. Spatially balanced topological interaction grants optimal cohesion in flocking models.

    Science.gov (United States)

    Camperi, Marcelo; Cavagna, Andrea; Giardina, Irene; Parisi, Giorgio; Silvestri, Edmondo

    2012-12-06

    Models of self-propelled particles (SPPs) are an indispensable tool to investigate collective animal behaviour. Originally, SPP models were proposed with metric interactions, where each individual coordinates with neighbours within a fixed metric radius. However, recent experiments on bird flocks indicate that interactions are topological: each individual interacts with a fixed number of neighbours, irrespective of their distance. It has been argued that topological interactions are more robust than metric ones against external perturbations, a significant evolutionary advantage for systems under constant predatory pressure. Here, we test this hypothesis by comparing the stability of metric versus topological SPP models in three dimensions. We show that topological models are more stable than metric ones. We also show that a significantly better stability is achieved when neighbours are selected according to a spatially balanced topological rule, namely when interacting neighbours are evenly distributed in angle around the focal individual. Finally, we find that the minimal number of interacting neighbours needed to achieve fully stable cohesion in a spatially balanced model is compatible with the value observed in field experiments on starling flocks.

  11. Social network cohesion in school classes promotes prosocial behavior

    Science.gov (United States)

    Crone, Eveline A.; Meuwese, Rosa; Güroğlu, Berna

    2018-01-01

    Adolescence is a key period of social development at the end of which individuals are expected to take on adult social roles. The school class, as the most salient peer group, becomes the prime environment that impacts social development during adolescence. Using social network analyses, we investigated how individual and group level features are related to prosocial behavior and social capital (generalized trust). We mapped the social networks within 22 classrooms of adolescents aged between 12 and 18 years (N = 611), and collected data on social behaviors towards peers. Our results indicate that individuals with high centrality show both higher levels of prosocial behavior and relational aggression. Importantly, greater social cohesion in the classroom was associated with (1) reduced levels of antisocial behavior towards peers and (2) increased generalized trust. These results provide novel insights in the relationship between social structure and social behavior, and stress the importance of the school environment in the development of not only intellectual but also social capital. PMID:29617405

  12. Grain boundary migration

    International Nuclear Information System (INIS)

    Dimitrov, O.

    1975-01-01

    Well-established aspects of grain-boundary migration are first briefly reviewed (influences of driving force, temperature, orientation and foreign atoms). Recent developments of the experimental methods and results are then examined, by considering the various driving of resistive forces acting on grain boundaries. Finally, the evolution in the theoretical models of grain-boundary motion is described, on the one hand for ideally pure metals and, on the other hand, in the presence of solute impurity atoms [fr

  13. Stable Boundary Layer Issues

    OpenAIRE

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The development of robust stable boundary layer parameterizations for use in NWP and climate models is hampered by the multiplicity of processes and their unknown interactions. As a result, these models suffer ...

  14. Assessment of boundary lubrication in biodiesels by nanotribological tests

    International Nuclear Information System (INIS)

    Maru, Marcia M.; Almeida, Clara M.; Silva, Rui F.; Achete, Carlos A.

    2013-01-01

    Nanoscale measurements using atomic force microscopy are performed in order to scrutinize the friction phenomena observed in microscale ball-on-disc tribological tests under (boundary lubrication) BL regime. Two reference biodiesels, one derived from a vegetable source (soybean) and the other from animal fat, are compared. A linear dependence of the friction coefficient (μ) with the Stribeck parameter (S = viscosity × velocity/load) is observed: μ = 0.11 − 26.54 × S for the animal fat and μ = 0.12 − 51.56 × S for the soybean biodiesel. The nanotribological tests allowed highlighting the cohesion component of friction force in the BL regime that is associated to the intrinsic characteristics of the biodiesels, the respective friction coefficients being μ = 0.0206 for the animal fat and μ = 0.0233 for the soybean biodiesel. The better lubricity of the animal fat biodiesel compared to the soybean observed in microscale is attributed to the presence of sulfur and to the higher amount of mono- and di-glycerides contaminants in it. The polarity and/or chemical affinity of the respective sulfur and OH groups facilitate them to reacting with the steel surfaces during the rubbing action. At nanoscale level, the same ranking in friction is observed among the biodiesels, being that here the friction phenomena are attributed to the cohesive forces other than those related to viscosity. - Highlights: • The frictional behavior of standard reference biodiesels is studied. • Nanotribology tests help scrutinizing microscale friction in boundary lubrication. • AFM tests allowed highlighting the cohesion component of friction in the BL regime. • Animal fat biodiesel promotes lower and more stable friction than soybean biodiesel

  15. Factors influencing the creep strength of hot pressed beryllium

    International Nuclear Information System (INIS)

    Webster, D.; Crooks, D.D.

    1975-01-01

    The parameters controlling the creep strength of hot pressed beryllium block have been determined. Creep strength was improved by a high initial dislocation density, a coarse grain size, and a low impurity content. The impurities most detrimental to creep strength were found to be aluminum, magnesium, and silicon. A uniform distribution of BeO was found to give creep strength which was inferior to a grain boundary distribution. The creep strength of very high purity, hot isostatically pressed beryllium was found to compare favorably with that of other more commonly used high temperature metals

  16. The cohesion protein SOLO associates with SMC1 and is required for synapsis, recombination, homolog bias and cohesion and pairing of centromeres in Drosophila Meiosis.

    Science.gov (United States)

    Yan, Rihui; McKee, Bruce D

    2013-01-01

    Cohesion between sister chromatids is mediated by cohesin and is essential for proper meiotic segregation of both sister chromatids and homologs. solo encodes a Drosophila meiosis-specific cohesion protein with no apparent sequence homology to cohesins that is required in male meiosis for centromere cohesion, proper orientation of sister centromeres and centromere enrichment of the cohesin subunit SMC1. In this study, we show that solo is involved in multiple aspects of meiosis in female Drosophila. Null mutations in solo caused the following phenotypes: 1) high frequencies of homolog and sister chromatid nondisjunction (NDJ) and sharply reduced frequencies of homolog exchange; 2) reduced transmission of a ring-X chromosome, an indicator of elevated frequencies of sister chromatid exchange (SCE); 3) premature loss of centromere pairing and cohesion during prophase I, as indicated by elevated foci counts of the centromere protein CID; 4) instability of the lateral elements (LE)s and central regions of synaptonemal complexes (SCs), as indicated by fragmented and spotty staining of the chromosome core/LE component SMC1 and the transverse filament protein C(3)G, respectively, at all stages of pachytene. SOLO and SMC1 are both enriched on centromeres throughout prophase I, co-align along the lateral elements of SCs and reciprocally co-immunoprecipitate from ovarian protein extracts. Our studies demonstrate that SOLO is closely associated with meiotic cohesin and required both for enrichment of cohesin on centromeres and stable assembly of cohesin into chromosome cores. These events underlie and are required for stable cohesion of centromeres, synapsis of homologous chromosomes, and a recombination mechanism that suppresses SCE to preferentially generate homolog crossovers (homolog bias). We propose that SOLO is a subunit of a specialized meiotic cohesin complex that mediates both centromeric and axial arm cohesion and promotes homolog bias as a component of chromosome

  17. Microtensile bond strength of enamel after bleaching

    Directory of Open Access Journals (Sweden)

    Andréa Dias Neves Lago

    2013-01-01

    Full Text Available Objective: To evaluate the bond strength of a composite resin to the bovine enamel bleached with 35% hydrogen peroxide. It was used an etching-and-rinse adhesive system employed immediately, 7 and 14 days after the bleaching. Materials and Methods: Twenty bovine teeth were randomly distributed into 4 groups (n = 5, 3 experimental and 1 control. G1: Unbleached + restoration 14 days after storage in artificial saliva (control; G2: Bleached + restoration immediately after bleaching; G3: Bleached + restoration 7 days after bleaching; G4: Bleached + restoration 14 days after bleaching. Their buccal enamel surfaces were flattened, and a 25 mm² (5 × 5 mm area from each one of these regions was outlined so as to standardize the experimental region. Universal hybrid composite resin Filtek™Z350 was inserted into four layers of 1 mm each and photo-activated. The bond strength was quantitatively evaluated by a microtensile test (1.0 mm/min 24 h after the restorative procedures. The failure mode was assessed through scanning electron microscopy (SEM. Results: There was a significant reduction in the bond strength of the restored teeth immediately after the bleaching (G2. There were no significant differences in enamel bond strength between groups G1, G3, and G4. There was a predominance of adhesive and mixed (cohesive + adhesive failure in all groups. Conclusion: The 7-day-period after the end of the bleaching with 35% hydrogen peroxide was enough to achieve the appropriate values of bond strength to the enamel.

  18. Numerical insight into the micromechanics of jet erosion of a cohesive granular material

    Directory of Open Access Journals (Sweden)

    Cuéllar Pablo

    2017-01-01

    Full Text Available Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet.

  19. Numerical insight into the micromechanics of jet erosion of a cohesive granular material

    Science.gov (United States)

    Cuéllar, Pablo; Benseghier, Zeyd; Luu, Li-Hua; Bonelli, Stéphane; Delenne, Jean-Yves; Radjaï, Farhang; Philippe, Pierre

    2017-06-01

    Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM) and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet.

  20. Roles of the sister chromatid cohesion apparatus in gene expression, development, and human syndromes

    Science.gov (United States)

    Dorsett, Dale

    2006-01-01

    The sister chromatid cohesion apparatus mediates physical pairing of duplicated chromosomes. This pairing is essential for appropriate distribution of chromosomes into the daughter cells upon cell division. Recent evidence shows that the cohesion apparatus, which is a significant structural component of chromosomes during interphase, also affects gene expression and development. The Cornelia de Lange (CdLS) and Roberts/SC phocomelia (RBS/SC) genetic syndromes in humans are caused by mutations affecting components of the cohesion apparatus. Studies in Drosophila suggest that effects on gene expression are most likely responsible for developmental alterations in CdLS. Effects on chromatid cohesion are apparent in RBS/SC syndrome, but data from yeast and Drosophila point to the likelihood that changes in expression of genes located in heterochromatin could contribute to the developmental deficits. PMID:16819604

  1. Transformational leadership and task cohesion in sport: the mediating role of inside sacrifice.

    Science.gov (United States)

    Cronin, Lorcan Donal; Arthur, Calum Alexander; Hardy, James; Callow, Nichola

    2015-02-01

    In this cross-sectional study, we examined a mediational model whereby transformational leadership is related to task cohesion via sacrifice. Participants were 381 American (Mage = 19.87 years, SD = 1.41) Division I university athletes (188 males, 193 females) who competed in a variety of sports. Participants completed measures of coach transformational leadership, personal and teammate inside sacrifice, and task cohesion. After conducting multilevel mediation analysis, we found that both personal and teammate inside sacrifice significantly mediated the relationships between transformational leadership behaviors and task cohesion. However, there were differential patterns of these relationships for male and female athletes. Interpretation of the results highlights that coaches should endeavor to display transformational leadership behaviors as they are related to personal and teammate inside sacrifices and task cohesion.

  2. A Molecular-Scale Understanding of Cohesion and Fracture in P3HT:Fullerene Blends

    KAUST Repository

    Tummala, Naga Rajesh; Bruner, Christopher; Risko, Chad; Bredas, Jean-Luc; Dauskardt, Reinhold H.

    2015-01-01

    mechanical flexibility, reliability, and lifetime. Here, the molecular mechanism for the initiation of cohesive failure in bulk heterojunction (BHJ) OPV active layers derived from the semiconducting polymer poly-(3-hexylthiophene) [P3HT] and two mono

  3. Unit Cohesion and the Military's "Don't Ask, Don't Tell" Policy

    National Research Council Canada - National Science Library

    Rea, Theresa

    1997-01-01

    The Department of Defense policy of excluding known homosexuals from military service is partially based on the assumption that homosexual service members pose a threat to the cohesion of a military unit...

  4. A Molecular-Scale Understanding of Cohesion and Fracture in P3HT:Fullerene Blends

    KAUST Repository

    Tummala, Naga Rajesh

    2015-04-21

    Quantifying cohesion and understanding fracture phenomena in thin-film electronic devices are necessary for improved materials design and processing criteria. For organic photovoltaics (OPVs), the cohesion of the photoactive layer portends its mechanical flexibility, reliability, and lifetime. Here, the molecular mechanism for the initiation of cohesive failure in bulk heterojunction (BHJ) OPV active layers derived from the semiconducting polymer poly-(3-hexylthiophene) [P3HT] and two mono-substituted fullerenes is examined experimentally and through molecular-dynamics simulations. The results detail how, under identical conditions, cohesion significantly changes due to minor variations in the fullerene adduct functionality, an important materials consideration that needs to be taken into account across fields where soluble fullerene derivatives are used.

  5. Great Expectations: How Role Expectations and Role Experiences Relate to Perceptions of Group Cohesion.

    Science.gov (United States)

    Benson, Alex J; Eys, Mark A; Irving, P Gregory

    2016-04-01

    Many athletes experience a discrepancy between the roles they expect to fulfill and the roles they eventually occupy. Drawing from met expectations theory, we applied response surface methodology to examine how role expectations, in relation to role experiences, influence perceptions of group cohesion among Canadian Interuniversity Sport athletes (N = 153). On the basis of data from two time points, as athletes approached and exceeded their role contribution expectations, they reported higher perceptions of task cohesion. Furthermore, as athletes approached and exceeded their social involvement expectations, they reported higher perceptions of social cohesion. These response surface patterns-pertaining to task and social cohesion-were driven by the positive influence of role experiences. On the basis of the interplay between athletes' role experiences and their perception of the group environment, efforts to improve team dynamics may benefit from focusing on improving the quality of role experiences, in conjunction with developing realistic role expectations.

  6. Appraisal in a Team Context: Perceptions of Cohesion Predict Competition Importance and Prospects for Coping.

    Science.gov (United States)

    Wolf, Svenja A; Eys, Mark A; Sadler, Pamela; Kleinert, Jens

    2015-10-01

    Athletes' precompetitive appraisal is important because it determines emotions, which may impact performance. When part of a team, athletes make their appraisal within a social context, and in this study we examined whether perceived team cohesion, as a characteristic of this context, related to appraisal. We asked 386 male and female intercollegiate team-sport athletes to respond to measures of cohesion and precompetitive appraisal before an in-season game. For males and females, across all teams, (a) an appraisal of increased competition importance was predicted by perceptions of higher task cohesion (individual level), better previous team performance, and a weaker opponent (team level) and (b) an appraisal of more positive prospects for coping with competitive demands was predicted by higher individual attractions to the group (individual level). Consequently, athletes who perceive their team as more cohesive likely appraise the pending competition as a challenge, which would benefit both emotions and performance.

  7. The strength compass

    DEFF Research Database (Denmark)

    Ledertoug, Mette Marie

    of agreement/disagreement. Also the child/teacher is asked whether the actual strength is important and if he or she has the possibilities to apply the strength in the school. In a PhDproject ‘Strengths-based Learning - Children’s Character Strengths as Means to their Learning Potential’ 750 Danish children......Individual paper presentation: The ‘Strength Compass’. The results of a PhDresearch project among schoolchildren (age 6-16) identifying VIAstrengths concerning age, gender, mother-tongue-langue and possible child psychiatric diagnosis. Strengths-based interventions in schools have a theoretical...... Psychological Publishing Company. ‘The Strength Compass’ is a computer/Ipad based qualitative tool to identify the strengths of a child by a self-survey or a teacher’s survey. It is designed as a visual analogue scale with a statement of the strength in which the child/teacher may declare the degree...

  8. Design of Normal Concrete Mixtures Using Workability-Dispersion-Cohesion Method

    OpenAIRE

    Qasrawi, Hisham

    2016-01-01

    The workability-dispersion-cohesion method is a new proposed method for the design of normal concrete mixes. The method uses special coefficients called workability-dispersion and workability-cohesion factors. These coefficients relate workability to mobility and stability of the concrete mix. The coefficients are obtained from special charts depending on mix requirements and aggregate properties. The method is practical because it covers various types of aggregates that may not be within sta...

  9. Cohesion assessment of student groups from the faculty of dentistry at Burdenko Voronezh State Medical University

    Directory of Open Access Journals (Sweden)

    Pashkov A. N.

    2017-10-01

    Full Text Available the article presents data on the study of the cohesion of 115 students from the faculty of dentistry at Burdenko Voronezh State Medical University. The study revealed that students have high and medium favorable psychological climate. 99 of them have the average level of group cohesion, and 16 revealed a low level of this indicator. To improve the educational process and interpersonal relations, these results must be taken into account when forming groups.

  10. Structural quality of polyacrylamide-treated cohesive soils in the coastal tablelands of Pernambuco

    Directory of Open Access Journals (Sweden)

    Diego Vandeval Maranhão de Melo

    2014-04-01

    Full Text Available Water-soluble polymers are characterized as effective flocculating agents due to their molecular features. Their application to soils with horizons with structural problems, e.g, a cohesive character, contributes to improvements in the physical quality and thus to the agricultural suitability of such soils. The purpose of this study was to evaluate the structural quality of soils with cohesive horizons of coastal tablelands in the State of Pernambuco treated with polyacrylamide (PAM as chemical soil conditioner. To this end, three horizons (one cohesive and two non-cohesive of a Yellow Argisol (Ultisol were evaluated and to compare cohesive horizons, the horizon of a Yellow Latosol (Oxisol was selected. The treatments consisted of aqueous PAM solutions (12.5; 50.0; 100.0 mg kg-1 and distilled water (control. The structural aspects of the horizons were evaluated by the stability (soil mass retained in five diameter classes, aggregate distribution per size class (mean weight diameter- MWD, geometric mean diameter - GMD and the magnitude of the changes introduced by PAM by measuring the sensitivity index (Si. Aqueous PAM solutions increased aggregate stability in the largest evaluated diameter class of the cohesive and non-cohesive horizons, resulting in higher MWD and GMD, with highest efficiency of the 100 mg kg-1 solution. The cohesive horizon Bt1 in the Ultisol was most sensitive to the action of PAM, where highest Si values were found, but the structural quality of the BA horizon of the Oxisol was better in terms of stability and aggregate size distribution.

  11. Relationship between Family Adaptability, Cohesion and Adolescent Problem Behaviors: Curvilinearity of Circumplex Model

    OpenAIRE

    Joh, Ju Youn; Kim, Sun; Park, Jun Li; Kim, Yeon Pyo

    2013-01-01

    Background The Family Adaptability and Cohesion Evaluation Scale (FACES) III using the circumplex model has been widely used in investigating family function. However, the criticism of the curvilinear hypothesis of the circumplex model has always been from an empirical point of view. This study examined the relationship between adolescent adaptability, cohesion, and adolescent problem behaviors, and especially testing the consistency of the curvilinear hypotheses with FACES III. Methods We us...

  12. A Strength Model and Service Envelope for PBX 9501

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-02-05

    An analytical method is proposed for making an assessment of the severity of the response of PBX 9501 in structural response simulations. The approach is based on the coherent use of a strength model and a failure criterion. The strength model is based on a creep rupture function and an associated cumulative damage model. The material's residual strength at any time during a simulation of structural response is determined by taking into account both the actual stress history up to that time, and a hypothetical continuation of the applied stresses that are assumed to grow until material failure results. The residual strength is used by the failure criterion to define the region of safe (non-failed) material response. The Mohr-Coulomb failure criterion is chosen for its general applicability to materials with both cohesive and frictional strength. The combined use of the residual strength model and the failure criterion provides a quantitative method of assessing the severity of the response of PBX 9501 material in structural simulations: the proximity of any evolving, general state of stress to the failure surface (which shrinks due to the cumulative damage caused by the past stress history) can be calculated and used as a measure of margin to failure. The strength model has been calibrated to a broad range of uniaxial tension and compression tests, and a small set of creep tests, and is applicable to a broad range of loading conditions.

  13. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  14. Thermal shale fracturing simulation using the Cohesive Zone Method (CZM)

    KAUST Repository

    Enayatpour, Saeid; van Oort, Eric; Patzek, Tadeusz

    2018-01-01

    Extensive research has been conducted over the past two decades to improve hydraulic fracturing methods used for hydrocarbon recovery from tight reservoir rocks such as shales. Our focus in this paper is on thermal fracturing of such tight rocks to enhance hydraulic fracturing efficiency. Thermal fracturing is effective in generating small fractures in the near-wellbore zone - or in the vicinity of natural or induced fractures - that may act as initiation points for larger fractures. Previous analytical and numerical results indicate that thermal fracturing in tight rock significantly enhances rock permeability, thereby enhancing hydrocarbon recovery. Here, we present a more powerful way of simulating the initiation and propagation of thermally induced fractures in tight formations using the Cohesive Zone Method (CZM). The advantages of CZM are: 1) CZM simulation is fast compared to similar models which are based on the spring-mass particle method or Discrete Element Method (DEM); 2) unlike DEM, rock material complexities such as scale-dependent failure behavior can be incorporated in a CZM simulation; 3) CZM is capable of predicting the extent of fracture propagation in rock, which is more difficult to determine in a classic finite element approach. We demonstrate that CZM delivers results for the challenging fracture propagation problem of similar accuracy to the eXtended Finite Element Method (XFEM) while reducing complexity and computational effort. Simulation results for thermal fracturing in the near-wellbore zone show the effect of stress anisotropy in fracture propagation in the direction of the maximum horizontal stress. It is shown that CZM can be used to readily obtain the extent and the pattern of induced thermal fractures.

  15. Thermal shale fracturing simulation using the Cohesive Zone Method (CZM)

    KAUST Repository

    Enayatpour, Saeid

    2018-05-17

    Extensive research has been conducted over the past two decades to improve hydraulic fracturing methods used for hydrocarbon recovery from tight reservoir rocks such as shales. Our focus in this paper is on thermal fracturing of such tight rocks to enhance hydraulic fracturing efficiency. Thermal fracturing is effective in generating small fractures in the near-wellbore zone - or in the vicinity of natural or induced fractures - that may act as initiation points for larger fractures. Previous analytical and numerical results indicate that thermal fracturing in tight rock significantly enhances rock permeability, thereby enhancing hydrocarbon recovery. Here, we present a more powerful way of simulating the initiation and propagation of thermally induced fractures in tight formations using the Cohesive Zone Method (CZM). The advantages of CZM are: 1) CZM simulation is fast compared to similar models which are based on the spring-mass particle method or Discrete Element Method (DEM); 2) unlike DEM, rock material complexities such as scale-dependent failure behavior can be incorporated in a CZM simulation; 3) CZM is capable of predicting the extent of fracture propagation in rock, which is more difficult to determine in a classic finite element approach. We demonstrate that CZM delivers results for the challenging fracture propagation problem of similar accuracy to the eXtended Finite Element Method (XFEM) while reducing complexity and computational effort. Simulation results for thermal fracturing in the near-wellbore zone show the effect of stress anisotropy in fracture propagation in the direction of the maximum horizontal stress. It is shown that CZM can be used to readily obtain the extent and the pattern of induced thermal fractures.

  16. Super heavy element Copernicium: Cohesive and electronic properties revisited

    Science.gov (United States)

    Gyanchandani, Jyoti; Mishra, Vinayak; Dey, G. K.; Sikka, S. K.

    2018-01-01

    First principles scalar relativistic (SR) calculations with and without including the spin orbit (SO) interactions have been performed for solid Copernicium (Cn) to determine its ground state equilibrium structure, volume, bulk modulus, pressure derivative of the bulk modulus, density of states and band structure. Both SR and SR+SO calculations have been performed with 6p levels treated as part of core electrons and also as part of valence electrons. These calculations have been performed for the rhombohedral, BCT, FCC, HCP, BCC and SC structures. Results have been compared with the results for Hg which is lighter homologue of Cn in the periodic table. We find hcp to be the stable crystal structure at SR level of theory and also at SR+SO level of theory when the 6p electrons are treated as part of core electrons. With 6p as part of valence electrons, SR+SO level of computations, however, yield bcc structure to be the most stable structure. Equilibrium volume (V0) of the most stable crystal structure at SR level of theory viz. hcp structure is 188.66 a.u.3whereas its value for the bcc structure, the equilibrium ground state structure at SR+SO level of theory is 165.71 a.u.3 i.e a large change due to relativistic effects is seen. The density of states at Fermi level is much smaller in Cn than in Hg, making it a poorer metal than mercury. In addition the cohesive energy of Cn is computed to be almost two times that of Hg for SR+SO case.

  17. Evaluating Lexical Cohesion in Nigerian Newspaper Genres: Focus on the Editorials

    Directory of Open Access Journals (Sweden)

    Zubairu Malah

    2016-11-01

    Full Text Available Applied linguists paying scholarly attention to newspaper genres have often argued that findings emerging from such studies would be of pedagogical significance because most of the newspaper genres share certain conventional features with school genres. Similarly, this study explored lexical cohesion in newspaper editorials, and it is understood that the findings could help learners in handling persuasive writings. The study sought to identify the dominant sources of lexical cohesion in the editorials, and also to examine how lexical cohesion is utilized to achieve coherence in the editorials. Drawing on Systemic Functional Linguistics (SFL, the study applied Eggins’ (2004 model of lexical cohesion and analyzed 30 editorial texts of 20, 354 words drawn from three major Nigerian newspapers: The Guardian, The Nation, and Vanguard. The analysis revealed 2, 685 ties across 849 sentences. The data demonstrated that the major types of lexical cohesion in the editorials include: repetition (49.5%, expectancy relations (15. 8%, class/sub-class (11%, and synonymy (10.8%. It was further revealed that lexical cohesion devices, which formed into chains (586 and isolated ties (837, were utilized in building coherence in the editorial texts. It was finally shown how findings of the study could be beneficial in ESP, EAP, and EGP learning, especially in persuasive writings.

  18. Are diverse societies less cohesive? Testing contact and mediated contact theories.

    Science.gov (United States)

    McKenna, Sarah; Lee, Eunro; Klik, Kathleen A; Markus, Andrew; Hewstone, Miles; Reynolds, Katherine J

    2018-01-01

    Previous research has demonstrated that there is a negative relationship between ethnic diversity in a local community and social cohesion. Often the way social cohesion is assessed, though, varies across studies and only some aspects of the construct are included (e.g., trust). The current research explores the relationship between diversity and social cohesion across a number of indicators of social cohesion including neighbourhood social capital, safety, belonging, generalized trust, and volunteering. Furthermore, social psychological theories concerning the role of positive contact and its impact on feelings of threat are investigated. Using a sample of 1070 third generation 'majority' Australians and structural equation modelling (SEM), findings suggest ethnic diversity is related to positive intergroup contact, and that contact showed beneficial impacts for some indicators of social cohesion both directly and indirectly through reducing perceived threat. When interethnic contact and perceived threat are included in the model there is no direct negative effect between diversity and social cohesion. The theoretical implications of these findings are outlined including the importance of facilitating opportunities for positive contact in diverse communities.

  19. Analysis of cohesion and collective efficacy profiles for the performance of soccer players.

    Science.gov (United States)

    Leo, Francisco M; Sánchez-Miguel, Pedro A; Sánchez-Oliva, David; Amado, Diana; García-Calvo, Tomás

    2013-12-18

    The principal aims of the study were to define different profiles of cohesion and perceived efficacy in soccer players and to measure their differences in performance. The subjects were 235 soccer players in the under-18 category who played in the National League in Spain and 15 coaches whose ages ranged from 29 to 45 years. Diverse instruments to assess cohesion, perceived efficacy, and expectations of success were used in the study. Moreover, we measured playing time and performance. The results of the study proved the existence of four cohesion and efficacy profiles that presented significant differences in expectations of success, playing time, and performance. Furthermore, significant differences were found in the distribution of players in the teams as a function of performance. The main conclusion of this study is that soccer players with higher cohesion and collective efficacy levels belonged to teams that completed the season at the top-level classification. In contrast, athletes with low cohesion and collective efficacy usually played in unsuccessful teams. Coaches and sports psychologists are encouraged to promote both social and task cohesion and collective efficacy to enhance team performance.

  20. The territorial approach to EU cohesion policy: Current issues and evidence from Greece

    Directory of Open Access Journals (Sweden)

    Thoidou Elisavet

    2011-01-01

    Full Text Available The importance attributed to the territorial dimension of the European Union cohesion policy steadily influences its successive reforms and adaptations, while in recent years there has been an evolution in the way this particular dimension of cohesion policy is perceived. Important evidence for this is the way in which the Community Strategic Guidelines on cohesion 2007-13 take account of the territorial dimension of cohesion policy. This paper discusses the territorial approach to cohesion policy in relation to both policy and practice. Specifically, it examines the territorial dimension of regional development planning in Greece as it has emerged in the relevant official documents, namely the successive three Community Support Frameworks since 1989 and the National Strategic Reference Framework for the current 2007-13 period. The territorial dimension of the organization of the planning system is also considered in an effort to understand limitations and prospects, in light of the importance of the territorial approach to cohesion policy post-2013.

  1. Authentic leadership, group cohesion and group identification in security and emergency teams.

    Science.gov (United States)

    García-Guiu López, Carlos; Molero Alonso, Fernando; Moya Morales, Miguel; Moriano León, Juan Antonio

    2015-01-01

    Authentic leadership (AL) is a kind of leadership that inspires and promotes positive psychological capacities, underlining the moral and ethical component of behavior. The proposed investigation studies the relations among AL, cohesion, and group identification in security and emergency teams. A cross-sectional research design was conducted in which participated 221 members from 26 fire departments and operative teams from the local police of three Spanish provinces. The following questionnaires were administered: Authentic Leadership (ALQ), Group Cohesion (GEQ), and Mael and Ashford's Group Identification Questionnaire. A direct and positive relation was found between AL, cohesion, and group identification. An indirect relation was also found between AL and group cohesion through group identification, indicating the existence of partial mediation. The utility of the proposed model based on AL is considered; this model can be employed by those in charge of the fire departments and operative groups in organizations to improve workteams' cohesion. Both AL and group identification help to explain group cohesion in organizations committed to security and emergencies.

  2. The role of bio-physical cohesive substrates on sediment winnowing and bedform development

    Science.gov (United States)

    Ye, Leiping; Parsons, Daniel; Manning, Andrew

    2017-04-01

    Existing sediment transport and bedform size predictions for natural open-channel flows in many environments are seriously impeded by a lack of process-based knowledge concerning the dynamics of complex bed sediment mixtures comprising cohesionless sand and biologically-active cohesive muds. A series of flume experiments (14 experimental runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substance) are combined with a detailed estuarine field survey (Dee estuary, NW England) to investigate the development of bedform morphologies and characteristics of suspended sediment over bio-physical cohesive substrates. The experimental results indicate that winnowing and sediment sorting can occur pervasively in bio-physical cohesive sediment - flow systems. Importantly however, the evolution of the bed and bedform dynamics, and hence turbulence production, is significantly reduced as bed substrate cohesivity increases. The estuarine subtidal zone survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed plays a significant role in controlling the interactions between bed substrate and sediment suspension, deposition and bedform generation. The work will be presented here concludes by outlining the need to extend and revisit the effects of cohesivity in morphodynamic systems and the sets of parameters presently used in numerical modelling, particularly in the context of the impact of climate change on estuarine and coastal systems.

  3. Perceived Social Cohesion, Frequency of Going Out, and Depressive Symptoms in Older Adults

    Directory of Open Access Journals (Sweden)

    Namkee G. Choi PhD

    2015-11-01

    Full Text Available Objective: To examine both cross-sectional and longitudinal relationships between older adults’ perceptions of social cohesion in their community and depressive symptoms and the potential mediating effect of the frequency of going outside one’s home/building. Method: Using two waves (T1 and T2 of the National Health and Aging Trend Study ( n = 5,326, gender-stratified structural equation models were estimated to determine direct and indirect effects of perceived social cohesion on depressive symptoms. Results: At T1, both perceived cohesion and frequency of going out were directly associated with depressive symptoms; however, perceived cohesion predicted frequency of going out only for women. At T2, only frequency of going out was directly associated with depressive symptoms, although perceived cohesion predicted frequency of going out for both genders. T1 perceived cohesion did not predict T2 depressive symptoms. T1 depressive symptoms were the strongest predictor of T2 depressive symptoms. Conclusion: The findings underscore the importance of enhancing the social environment in promoting mental health in late life through active aging.

  4. Development of boundary layers

    International Nuclear Information System (INIS)

    Herbst, R.

    1980-01-01

    Boundary layers develop along the blade surfaces on both the pressure and the suction side in a non-stationary flow field. This is due to the fact that there is a strongly fluctuating flow on the downstream blade row, especially as a result of the wakes of the upstream blade row. The author investigates the formation of boundary layers under non-stationary flow conditions and tries to establish a model describing the non-stationary boundary layer. For this purpose, plate boundary layers are measured, at constant flow rates but different interferent frequency and variable pressure gradients. By introducing the sample technique, measurements of the non-stationary boundary layer become possible, and the flow rate fluctuation can be divided in its components, i.e. stochastic turbulence and periodical fluctuation. (GL) [de

  5. Damage initiation and propagation in composite materials boundary element analysis using weak interface and cohesive zone models

    OpenAIRE

    Távara Mendoza, Luis Arístides

    2010-01-01

    La presente tesis ha sido desarrollada en el Grupo de Elasticidad y Resistencia de Materiales, Departamento de Mecánica de Medios Continuos, Teoría de Estructuras e Ingeniería del Terreno de la Universidad de Sevilla. El trabajo se centra en dos líneas de investigaci ... ón del Grupo de Elasticidad y Resistencia de Materiales:(i) El desarrollo de diferentes modelos de mecánica de la fractura y su implementación en algunos códigos basados en el Método de los Elementos de Contorno (MEC), usados...

  6. Influence of boundary conditions on the response of multilayered plates with cohesive interfaces and delaminations using a homogenized approach

    Directory of Open Access Journals (Sweden)

    R. Massabò

    2014-07-01

    Full Text Available Stress and displacement fields in multilayered composites with interfacial imperfections, such as imperfect bonding of the layers or delaminations, or where the plies are separated by thin interlayers allowing relative motion, have large variations in the thickness, with characteristic zigzag patterns and jumps at the layer interfaces. These effects are well captured by a model recently formulated by the author for multilayered plates with imperfect interfaces and affine interfacial traction laws (Massabò & Campi, Meccanica, 2014, in press; Compos Struct, 2014, 116, 311-324. The model defines a homogenized displacement field, which satisfies interfacial continuity, and uses a variational technique to derive equilibrium equations depending on only six generalized displacement functions, for any arbitrary numbers of layers and interfaces. The model accurately predicts stresses and displacements in simply supported, highly anisotropic, thick plates with continuous, sliding interfaces. In this paper the model is applied to wide plates with clamped edges and some inconsistencies, which have been noted in the literature for models based on similar approaches and have limited their utilization, are explained. A generalized transverse shear force is introduced as the gross stress resultant which is directly related to the bending moment in the equilibrium equations of multilayered structures with imperfect interfaces and substitutes for the shear force of single-layer theory. An application to a delaminated wide plate highlights the potential and limitations of the proposed model for the solution of fracture mechanics problems.

  7. Quantum Ising chains with boundary fields

    International Nuclear Information System (INIS)

    Campostrini, Massimo; Vicari, Ettore; Pelissetto, Andrea

    2015-01-01

    We present a detailed study of the finite one-dimensional quantum Ising chain in a transverse field in the presence of boundary magnetic fields coupled with the order-parameter spin operator. We consider two magnetic fields located at the boundaries of the chain that have the same strength and that are aligned in the same or in the opposite direction. We derive analytic expressions for the gap in all phases for large values of the chain length L, as a function of the boundary field strength. We also investigate the behaviour of the chain in the quantum ferromagnetic phase for oppositely aligned fields, focusing on the magnet-to-kink transition that occurs at a finite value of the magnetic field strength. At this transition we compute analytically the finite-size crossover functions for the gap, the magnetisation profile, the two-point correlation function, and the density of fermionic modes. As the magnet-to-kink transition is equivalent to the wetting transition in two-dimensional classical Ising models, our results provide new analytic predictions for the finite-size behaviour of Ising systems in a strip geometry at this transition. (paper)

  8. Comparison of Shear Strength Properties for Undisturbed and Reconstituted Parit Nipah Peat, Johor

    Science.gov (United States)

    Azhar, A. T. S.; Norhaliza, W.; Ismail, B.; Abdullah, M. E.; Zakaria, M. N.

    2016-11-01

    Shear strength of soil is required to determine the soil stability and design the foundations. Peat is known as a soil with complex natural formations which also contributes problems to the researchers, developers, engineers and contractors in constructions and infrastructures. Most researchers conducted experiment and investigation of shear strength on peat using shear box test and simple shear test, but only a few had discovered the behavior of peat using triaxial consolidated undrained test. The aim of this paper is to determine the undrained shear strength properties of reconstituted peat and undisturbed peat of Parit Nipah, Johor for comparison purposes. All the reconstituted peat samples were formed with the size that passed opening sieve 3.35 mm and preconsolidation pressure at 100 kPa. The result of undrained shear strength of reconstituted peat was 21kPa for cohesion with the angle of friction, 41° compare to the undisturbed peat with cohesion 10 kPa and angle of friction, 16°. The undrained shear strength properties result obtained shows that the reconstituted peat has higher strength than undisturbed peat. For relationship deviator stress-strain, σd max and excess pore pressure, Δu, it shows that both of undisturbed and reconstituted gradually increased when σ’ increased, but at the end of the test, the values are slightly dropped. The physical properties of undisturbed and reconstituted peat were also investigated to correlate with the undrained shear strength results.

  9. 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.

  10. Shear strength characteristics of mechanically biologically treated municipal solid waste (MBT-MSW) from Bangalore

    International Nuclear Information System (INIS)

    Sivakumar Babu, G.L.; Lakshmikanthan, P.; Santhosh, L.G.

    2015-01-01

    Highlights: • Shear strength properties of mechanically biologically treated municipal solid waste. • Effect of unit weight and particle size on the shear strength of waste. • Effect of particle size on the strength properties. • Stiffness ratio and the strength ratio of MSW. - Abstract: Strength and stiffness properties of municipal solid waste (MSW) are important in landfill design. This paper presents the results of comprehensive testing of shear strength properties of mechanically biologically treated municipal solid waste (MBT-MSW) in laboratory. Changes in shear strength of MSW as a function of unit weight and particle size were investigated by performing laboratory studies on the MSW collected from Mavallipura landfill site in Bangalore. Direct shear tests, small scale and large scale consolidated undrained and drained triaxial tests were conducted on reconstituted compost reject MSW samples. The triaxial test results showed that the MSW samples exhibited a strain-hardening behaviour and the strength of MSW increased with increase in unit weight. Consolidated drained tests showed that the mobilized shear strength of the MSW increased by 40% for a unit weight increase from 7.3 kN/m 3 to 10.3 kN/m 3 at 20% strain levels. The mobilized cohesion and friction angle ranged from 5 to 9 kPa and 8° to 33° corresponding to a strain level of 20%. The consolidated undrained tests exhibited reduced friction angle values compared to the consolidated drained tests. The friction angle increased with increase in the unit weight from 8° to 55° in the consolidated undrained tests. Minor variations were found in the cohesion values. Relationships for strength and stiffness of MSW in terms of strength and stiffness ratios are developed and discussed. The stiffness ratio and the strength ratio of MSW were found to be 10 and 0.43

  11. Shear strength characteristics of mechanically biologically treated municipal solid waste (MBT-MSW) from Bangalore

    Energy Technology Data Exchange (ETDEWEB)

    Sivakumar Babu, G.L., E-mail: gls@civil.iisc.ernet.in [Department of Civil Engineering, Indian Institute of Science, Bangalore 560012 (India); Lakshmikanthan, P., E-mail: lakshmikanthancp@gmail.com [Centre for Sustainable Technologies (CST), Indian Institute of Science, Bangalore 560012 (India); Santhosh, L.G., E-mail: lgsanthu2006@gmail.com [Centre for Sustainable Technologies (CST), Indian Institute of Science, Bangalore 560012 (India)

    2015-05-15

    Highlights: • Shear strength properties of mechanically biologically treated municipal solid waste. • Effect of unit weight and particle size on the shear strength of waste. • Effect of particle size on the strength properties. • Stiffness ratio and the strength ratio of MSW. - Abstract: Strength and stiffness properties of municipal solid waste (MSW) are important in landfill design. This paper presents the results of comprehensive testing of shear strength properties of mechanically biologically treated municipal solid waste (MBT-MSW) in laboratory. Changes in shear strength of MSW as a function of unit weight and particle size were investigated by performing laboratory studies on the MSW collected from Mavallipura landfill site in Bangalore. Direct shear tests, small scale and large scale consolidated undrained and drained triaxial tests were conducted on reconstituted compost reject MSW samples. The triaxial test results showed that the MSW samples exhibited a strain-hardening behaviour and the strength of MSW increased with increase in unit weight. Consolidated drained tests showed that the mobilized shear strength of the MSW increased by 40% for a unit weight increase from 7.3 kN/m{sup 3} to 10.3 kN/m{sup 3} at 20% strain levels. The mobilized cohesion and friction angle ranged from 5 to 9 kPa and 8° to 33° corresponding to a strain level of 20%. The consolidated undrained tests exhibited reduced friction angle values compared to the consolidated drained tests. The friction angle increased with increase in the unit weight from 8° to 55° in the consolidated undrained tests. Minor variations were found in the cohesion values. Relationships for strength and stiffness of MSW in terms of strength and stiffness ratios are developed and discussed. The stiffness ratio and the strength ratio of MSW were found to be 10 and 0.43.

  12. Symptom fluctuations, self-esteem, and cohesion during group cognitive behaviour therapy for early psychosis.

    Science.gov (United States)

    Lecomte, Tania; Leclerc, Claude; Wykes, Til

    2018-03-01

    Group cohesion has been linked to positive changes in self-esteem and in symptoms during group psychotherapy in people with psychosis. These changes may be linked to changes in symptoms as fluctuations in self-esteem have been linked to symptom fluctuations. We aimed to determine the relationship between these three factors - group cohesion, self-esteem, and symptoms - during group cognitive behaviour therapy for psychosis (GCBTp). We hypothesized that group cohesion would precede changes in symptoms and self-esteem and that improvements in self-esteem would precede improvements in symptoms. This is an uncontrolled longitudinal study recruiting from a convenience sample within two early psychosis clinics. Sixty-six individuals from first episode of psychosis treatment programmes participated in this study and received 24 sessions of a validated GCBTp protocol. Participants answered a brief questionnaire at the end of each session, measuring their group cohesion, self-esteem, and perception of their symptoms as worse, same, or better than usual. Orthogonal polynomial contrasts for time effects were estimated with a mixed model for repeated measures with a random cluster effect and revealed a quartic trend regarding changes in symptoms over the 24 sessions. Self-esteem, symptoms, and group cohesion were strongly linked during a given session. Also, self-esteem changes predicted changes in symptoms up to two sessions later, and symptoms changes predicted self-esteem changes at the next session. Group cohesion preceded improvements in both self-esteem and symptoms; self-esteem also predicted improvements in group cohesion. These results suggest that self-esteem and symptoms influence each other during therapy, with improvements in one leading to improvements in the other. Group cohesion also appears to be an essential prerequisite to positive changes in self-esteem and symptoms during GCBTp. This study emphasizes the interrelation between self-esteem improvements and

  13. Administrative Area Boundaries 2 (State Boundaries), Region 9, 2010, NAVTEQ

    Data.gov (United States)

    U.S. Environmental Protection Agency — NAVTEQ Administrative Area Boundaries 2 (State Boundaries) for Region 9. There are five Administrative Area Boundaries layers (1, 2, 3, 4, 5). These layers contain...

  14. Administrative Area Boundaries 4 (City Boundaries), Region 9, 2010, NAVTEQ

    Data.gov (United States)

    U.S. Environmental Protection Agency — NAVTEQ Administrative Area Boundaries 4 (City Boundaries) for Region 9. There are five Administrative Area Boundaries layers (1, 2, 3, 4, 5). These layers contain...

  15. The magnetic nature of umbra-penumbra boundary in sunspots

    Science.gov (United States)

    Jurčák, J.; Rezaei, R.; González, N. Bello; Schlichenmaier, R.; Vomlel, J.

    2018-03-01

    Context. Sunspots are the longest-known manifestation of solar activity, and their magnetic nature has been known for more than a century. Despite this, the boundary between umbrae and penumbrae, the two fundamental sunspot regions, has hitherto been solely defined by an intensity threshold. Aim. Here, we aim at studying the magnetic nature of umbra-penumbra boundaries in sunspots of different sizes, morphologies, evolutionary stages, and phases of the solar cycle. Methods: We used a sample of 88 scans of the Hinode/SOT spectropolarimeter to infer the magnetic field properties in at the umbral boundaries. We defined these umbra-penumbra boundaries by an intensity threshold and performed a statistical analysis of the magnetic field properties on these boundaries. Results: We statistically prove that the umbra-penumbra boundary in stable sunspots is characterised by an invariant value of the vertical magnetic field component: the vertical component of the magnetic field strength does not depend on the umbra size, its morphology, and phase of the solar cycle. With the statistical Bayesian inference, we find that the strength of the vertical magnetic field component is, with a likelihood of 99%, in the range of 1849-1885 G with the most probable value of 1867 G. In contrast, the magnetic field strength and inclination averaged along individual boundaries are found to be dependent on the umbral size: the larger the umbra, the stronger and more horizontal the magnetic field at its boundary. Conclusions: The umbra and penumbra of sunspots are separated by a boundary that has hitherto been defined by an intensity threshold. We now unveil the empirical law of the magnetic nature of the umbra-penumbra boundary in stable sunspots: it is an invariant vertical component of the magnetic field.

  16. DEVELOPMENT OF REGIONS AND MUNICIPALITIES OF THE SLOVAK REPUBLIC BY APPLICATION OF EUROPEAN COHESION POLICY

    Directory of Open Access Journals (Sweden)

    Katarina Rentkova

    2017-03-01

    Full Text Available The Slovak republic, entering the European Union on the 1st May 2004, got the impulse on the improvement and growth also via the application of the Cohesion policy. For the programming period 2007-2013, the amount of 11.3 milliards Euros for the application of the Cohesion policy have been provided to the Slovak republic. In the present time, the programming period is finished and the Slovak republic meets the critical reviews in the area of the effective use and maintenance of projects and application of the Cohesion policy on its territory. Many specialists, economists and analysts try to reveal the errors, identify the subjects that enter into the project cycle wrongly or to identify the bodies that have the most important influence on the low level of the financial instruments use and they also try to deal with the criticism of the European Commission as to the project realization. From this point of view, the theme of the research is very actual and imperative because the research tries to enlighten and to analyze the application of the cohesion policy within the territory of the Slovak republic and so, to state recommendations for more effective application for the following programming period. The article is created by analyzing the application of the European cohesion policy in the programming period 2007 - 2013 in the Slovak Republic. The main objective of the article is to analyze and define the cohesion policy of the European Union and one of the partial objectives is to execute the analysis on the implementation state of the Cohesion policy on the level of the chosen regions in the Slovak republic and then, to propose and to create recommendations and techniques for its effective functioning.

  17. Strengths-based Learning

    DEFF Research Database (Denmark)

    Ledertoug, Mette Marie

    -being. The Ph.D.-project in Strength-based learning took place in a Danish school with 750 pupils age 6-16 and a similar school was functioning as a control group. The presentation will focus on both the aware-explore-apply processes and the practical implications for the schools involved, and on measurable......Strength-based learning - Children͛s Character Strengths as Means to their Learning Potential͛ is a Ph.D.-project aiming to create a strength-based mindset in school settings and at the same time introducing strength-based interventions as specific tools to improve both learning and well...

  18. Modeling the effect of preexisting joints on normal fault geometries using a brittle and cohesive material

    Science.gov (United States)

    Kettermann, M.; van Gent, H. W.; Urai, J. L.

    2012-04-01

    Brittle rocks, such as for example those hosting many carbonate or sandstone reservoirs, are often affected by different kinds of fractures that influence each other. Understanding the effects of these interactions on fault geometries and the formation of cavities and potential fluid pathways might be useful for reservoir quality prediction and production. Analogue modeling has proven to be a useful tool to study faulting processes, although usually the used materials do not provide cohesion and tensile strength, which are essential to create open fractures. Therefore, very fine-grained, cohesive, hemihydrate powder was used for our experiments. The mechanical properties of the material are scaling well for natural prototypes. Due to the fine grain size structures are preserved in in great detail. The used deformation box allows the formation of a half-graben and has initial dimensions of 30 cm width, 28 cm length and 20 cm height. The maximum dip-slip along the 60° dipping predefined basement fault is 4.5 cm and was fully used in all experiments. To setup open joints prior to faulting, sheets of paper placed vertically within the box to a depth of about 5 cm from top. The powder was then sieved into the box, embedding the paper almost entirely. Finally strings were used to remove the paper carefully, leaving open voids. Using this method allows the creation of cohesionless open joints while ensuring a minimum impact on the sensitive surrounding material. The presented series of experiments aims to investigate the effect of different angles between the strike of a rigid basement fault and a distinct joint set. All experiments were performed with a joint spacing of 2.5 cm and the fault-joint angles incrementally covered 0°, 4°, 8°, 12°, 16°, 20° and 25°. During the deformation time lapse photography from the top and side captured every structural change and provided data for post-processing analysis using particle imaging velocimetry (PIV). Additionally

  19. Tax Unit Boundaries

    Data.gov (United States)

    Kansas Data Access and Support Center — The Statewide GIS Tax Unit boundary file was created through a collaborative partnership between the State of Kansas Department of Revenue Property Valuation...

  20. 500 Cities: City Boundaries

    Data.gov (United States)

    U.S. Department of Health & Human Services — This city boundary shapefile was extracted from Esri Data and Maps for ArcGIS 2014 - U.S. Populated Place Areas. This shapefile can be joined to 500 Cities...

  1. National Forest Boundaries

    Data.gov (United States)

    Minnesota Department of Natural Resources — This theme shows the USFS national forest boundaries in the state. This data was acquired from the GIS coordinators at both the Chippewa National Forest and the...

  2. Allegheny County Parcel Boundaries

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset contains parcel boundaries attributed with county block and lot number. Use the Property Information Extractor for more control downloading a filtered...

  3. Boundary representation modelling techniques

    CERN Document Server

    2006-01-01

    Provides the most complete presentation of boundary representation solid modelling yet publishedOffers basic reference information for software developers, application developers and users Includes a historical perspective as well as giving a background for modern research.

  4. NM School District Boundaries

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The dataset represents the boundaries of all public school districts in the state of New Mexico. The source for the data layer is the New Mexico Public Education...

  5. Site Area Boundaries

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset consists of site boundaries from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different times and...

  6. HUC 8 Boundaries

    Data.gov (United States)

    Kansas Data Access and Support Center — This data set is a digital hydrologic unit boundary that is at the 4-digit, 6-digit, 8-digit, and 11-digit level. The data set was developed by delineating the...

  7. State Park Statutory Boundaries

    Data.gov (United States)

    Minnesota Department of Natural Resources — Legislative statutory boundaries for sixty six state parks, six state recreation areas, and eight state waysides. These data are derived principally from DNR's...

  8. Family cohesion, acculturation, maternal cortisol, and preterm birth in Mexican-American women

    Directory of Open Access Journals (Sweden)

    Ruiz RJ

    2013-05-01

    Full Text Available R Jeanne Ruiz,1 Rita H Pickler,2 C Nathan Marti,3 Nancy Jallo41College of Nursing, The Ohio State University, Columbus, OH, USA; 2Department of Patient Services, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; 3Abacist Analytics, Austin, TX, USA; 4School of Nursing, Virginia Commonwealth University, Richmond, VA, USAObjective: To examine the potential moderating effects of family cohesion and acculturation on the physiological stress response (cortisol as a predictor of preterm birth (PTB in pregnant Mexican-American women.Methods: The sample included 470 participants; 33 had preterm births. All participants were self-identified as Mexican-American. In this cross-sectional study, family cohesion was measured by a self-report questionnaire. Acculturation was measured by self-report questionnaire as well as by years in the United States and country of birth. Stress was measured by serum cortisol. All measures were obtained at 22—24 weeks gestation. Additional data including history of PTB were obtained from the health record. Data analysis was primarily conducted using logistic regression.Results: The relationship between stress and PTB was predicted by family cohesion (estimate/standard error [E/SE] = —2.46, P = 0.014 and acculturation (E/SE = 2.56, P = 0.011. In addition, there was an interaction between family cohesion and history of previous PTB (E/SE = —2.12, P = 0.035.Conclusion: Results indicate that the impact of cortisol on PTB is predicted by acculturation and family cohesion such that higher levels of cortisol in conjunction with higher levels of acculturation and lower levels of family cohesion are associated with increased risk of PTB. In addition, low family cohesion in combination with a history of PTB was associated with higher levels of PTB. Assessment of family cohesion, including problem solving, adherence to family decisions, family shared space, and activity, should be included as part of prenatal

  9. Crystallography and Interphase Boundary of Martensite and Bainite in Steels

    Science.gov (United States)

    Furuhara, Tadashi; Chiba, Tadachika; Kaneshita, Takeshi; Wu, Huidong; Miyamoto, Goro

    2017-06-01

    Grain refinements in lath martensite and bainite structures are crucial for strengthening and toughening of high-strength structural steels. Clearly, crystallography of transformation plays an important role in determining the "grain" sizes in these structures. In the present study, crystallography and intrinsic boundary structure of martensite and bainite are described. Furthermore, various extrinsic factors affecting variant selection and growth kinetics, such as elastic/plastic strain and alloying effects on interphase boundary migration, are discussed.

  10. Social cohesion and social capital: Possible implications for the common good

    Directory of Open Access Journals (Sweden)

    Anita Cloete

    2014-08-01

    Full Text Available The main objective of the article is to identify the possible implications of social cohesion and social capital for the common good. In order to reach this overarching aim the following structure will be utilised. The first part explores the conceptual understanding of socialcohesion and social capital in order to establish how these concepts are related and how they could possibly inform each other. The contextual nature of social cohesion and social capital is briefly reflected upon, with specific reference to the South African context. The contribution of religious capital in the formation of social capital is explored in the last section of the article. The article could be viewed as mainly conceptual and explorative in nature in order to draw some conclusions about the common good of social capital and social cohesion.Intradisciplinary and/or interdisciplinary implications: This article contributes to the interdisciplinary discourse on social cohesion with specific reference to the role of congregations. It provides a critical reflection on the role of congregations with regard to bonding and bridging social capital. The contextual nature of social cohesion is also addressed with specific reference to South Africa.

  11. Sense of belonging and social cohesion in a desegregated former House of Delegates school

    Directory of Open Access Journals (Sweden)

    Ramodungoane Tabane

    2010-01-01

    Full Text Available The ideal of creating a non-racial and equitable school environment is embedded in the South African Constitution. This ideal is informed by a desire to overcome the divisions of the apartheid past by pursuing policies and strategies that will promote the achievement of social cohesion, without denying space for various identities. Schools are seen as important vehicles for driving social cohesion amongst learners and it is therefore important that all learners, irrespective of their race, experience a sense of belonging in the school. Using a case study and an interactive qualitative analysis research methodology, we explored the experiences of black and Indian learners in a desegregated former House of Delegates school to determine the successes and possible challenges of ensuring racial integration at the school level and therefore its contribution to social cohesion. The study demonstrates the importance of eight concepts (namely, the school as a welcoming space; belonging; respect; security; equality in the way we socialise; tender loving care; motivation; and freedom to the study of racial integration and social cohesion. This article focuses on the contribution that sense of belonging has on creating a school environment that is enabling, contributing to learner achievement and concludes that sense of belonging, integration, and social cohesion are intertwined and important in creating an environment that is welcoming and a "home" to diverse learners and educators.

  12. Stress of home life and gender role socializations, family cohesion, and symptoms of anxiety and depression.

    Science.gov (United States)

    Anyan, Frederick; Hjemdal, Odin

    2017-04-05

    This cross-sectional study investigated the relation of sociocultural prescriptions of gender role socializations to differences in stress at home and to anxiety and depressive symptoms for adolescent girls and boys, with family cohesion as a mediator. A total of 244 boys and 285 girls aged 13-17 years recruited from Accra, Ghana completed the Short Mood Feeling Questionnaire, Spielberger State Anxiety Inventory, Stress of Home Life and Family Cohesion self-report scales in April 2015. In each sample, two mediation analyses were conducted using Structural Equation Modelling. Exposure to stress at home that was perceived to result from sociocultural prescriptions of gender role norms largely accounted for anxiety and depressive symptoms among girls, whereas this relation was non-significant among boys. Significant indirect relations through low family cohesion to anxiety symptoms were observed for girls and boys but not to depressive symptoms for boys. These findings suggest that differences in gender role socializations at home may account for individual differences in associations between exposure to stress at home and anxiety and depressive symptoms as well as explain the differential indirect relations through low family cohesion. Improving family cohesion while reducing stress at home may contribute to reducing stress and thus anxiety and depressive symptoms.

  13. Relationship between Family Adaptability, Cohesion and Adolescent Problem Behaviors: Curvilinearity of Circumplex Model

    Science.gov (United States)

    Joh, Ju Youn; Kim, Sun; Park, Jun Li

    2013-01-01

    Background The Family Adaptability and Cohesion Evaluation Scale (FACES) III using the circumplex model has been widely used in investigating family function. However, the criticism of the curvilinear hypothesis of the circumplex model has always been from an empirical point of view. This study examined the relationship between adolescent adaptability, cohesion, and adolescent problem behaviors, and especially testing the consistency of the curvilinear hypotheses with FACES III. Methods We used the data from 398 adolescent participants who were in middle school. A self-reported questionnaire was used to evaluate the FACES III and Youth Self Report. Results According to the level of family adaptability, significant differences were evident in internalizing problems (P = 0.014). But, in externalizing problems, the results were not significant (P = 0.305). Also, according to the level of family cohesion, significant differences were in internalizing problems (P = 0.002) and externalizing problems (P = 0.004). Conclusion The relationship between the dimensions of adaptability, cohesion and adolescent problem behaviors was not curvilinear. In other words, adolescents with high adaptability and high cohesion showed low problem behaviors. PMID:23730484

  14. Topographic Signatures of Meandering Rivers with Differences in Outer Bank Cohesion

    Science.gov (United States)

    Kelly, S. A.; Belmont, P.

    2014-12-01

    Within a given valley setting, interactions between river hydraulics, sediment, topography, and vegetation determine attributes of channel morphology, including planform, width and depth, slope, and bed and bank properties. These feedbacks also govern river behavior, including migration and avulsion. Bank cohesion, from the addition of fine sediment and/or vegetation has been recognized in flume experiments as a necessary component to create and maintain a meandering channel planform. Greater bank cohesion slows bank erosion, limiting the rate at which a river can adjust laterally and preventing so-called "runaway widening" to a braided state. Feedbacks of bank cohesion on channel hydraulics and sediment transport may thus produce distinct topographic signatures, or patterns in channel width, depth, and point bar transverse slope. We expect that in bends of greater outer bank cohesion the channel will be narrower, deeper, and bars will have greater transverse slopes. Only recently have we recognized that biotic processes may imprint distinct topographic signatures on the landscape. This study explores topographic signatures of three US rivers: the lower Minnesota River, near Mankato, MN, the Le Sueur River, south central MN, and the Fall River, Rocky Mountain National Park, CO. Each of these rivers has variability in outer bank cohesion, quantified based on geotechnical and vegetation properties, and in-channel topography, which was derived from rtkGPS and acoustic bathymetry surveys. We present methods for incorporating biophysical feedbacks into geomorphic transport laws so that models can better simulate the spatial patterns and variability of topographic signatures.

  15. Development of a cohesion questionnaire for youth: the Youth Sport Environment Questionnaire.

    Science.gov (United States)

    Eys, Mark; Loughead, Todd; Bray, Steven R; Carron, Albert V

    2009-06-01

    The purpose of the current study was to initiate the development of a psychometrically sound measure of cohesion for youth sport groups. A series of projects were undertaken in a four-phase research program. The initial phase was designed to garner an understanding of how youth sport group members perceived the concept of cohesion through focus groups (n = 56), open-ended questionnaires (n = 280), and a literature review. In Phase 2, information from the initial projects was used in the development of 142 potential items and content validity was assessed. In Phase 3, 227 participants completed a revised 87-item questionnaire. Principal components analyses further reduced the number of items to 17 and suggested a two-factor structure (i.e., task and social cohesion dimensions). Finally, support for the factorial validity of the resultant questionnaire was provided through confirmatory factor analyses with an independent sample (n = 352) in Phase 4. The final version of the questionnaire contains 16 items that assess task and social cohesion in addition to 2 negatively worded spurious items. Specific issues related to assessing youth perceptions of cohesion are discussed and future research directions are suggested.

  16. Cohesion, team mental models, and collective efficacy: towards an integrated framework of team dynamics in sport.

    Science.gov (United States)

    Filho, Edson; Tenenbaum, Gershon; Yang, Yanyun

    2015-01-01

    A nomological network on team dynamics in sports consisting of a multiframework perspective is introduced and tested. The aim was to explore the interrelationship among cohesion, team mental models (TMMs), collective efficacy (CE) and perceived performance potential (PPP). Three hundred and forty college-aged soccer players representing 17 different teams (8 female and 9 male) participated in the study. They responded to surveys on team cohesion, TMMs, CE and PPP. Results are congruent with the theoretical conceptualisation of a parsimonious view of team dynamics in sports. Specifically, cohesion was found to be an exogenous variable predicting both TMMs and CE beliefs. TMMs and CE were correlated and predicted PPP, which in turn accounted for 59% of the variance of objective performance scores as measured by teams' season record. From a theoretical standpoint, findings resulted in a parsimonious view of team dynamics, which may represent an initial step towards clarifying the epistemological roots and nomological network of various team-level properties. From an applied standpoint, results suggest that team expertise starts with the establishment of team cohesion. Following the establishment of cohesiveness, teammates are able to advance team-related schemas and a collective sense of confidence. Limitations and key directions for future research are outlined.

  17. Group cohesion in foraging meerkats: follow the moving 'vocal hot spot'.

    Science.gov (United States)

    Gall, Gabriella E C; Manser, Marta B

    2017-04-01

    Group coordination, when 'on the move' or when visibility is low, is a challenge faced by many social living animals. While some animals manage to maintain cohesion solely through visual contact, the mechanism of group cohesion through other modes of communication, a necessity when visual contact is reduced, is not yet understood. Meerkats ( Suricata suricatta ), a small, social carnivore, forage as a cohesive group while moving continuously. While foraging, they frequently emit 'close calls', soft close-range contact calls. Variations in their call rates based on their local environment, coupled with individual movement, produce a dynamic acoustic landscape with a moving 'vocal hotspot' of the highest calling activity. We investigated whether meerkats follow such a vocal hotspot by playing back close calls of multiple individuals to foraging meerkats from the front and back edge of the group simultaneously. These two artificially induced vocal hotspots caused the group to spatially elongate and split into two subgroups. We conclude that meerkats use the emergent dynamic call pattern of the group to adjust their movement direction and maintain cohesion. Our study describes a highly flexible mechanism for the maintenance of group cohesion through vocal communication, for mobile species in habitats with low visibility and where movement decisions need to be adjusted continuously to changing environmental conditions.

  18. [Team cohesiveness: opinions of a group of primary health care professionals from Salamanca].

    Science.gov (United States)

    González, F J; de Cabo, A; Morán, M J; Manzano, J M

    1993-04-01

    To assess the view of a group of Primary care professionals on their level of perception of group cohesiveness in their teams' work dynamic. A descriptive and sectional study. Four urban health centres in Salamanca with a recognised teaching activity. Both health professionals and those outside the Health Service, working in Primary Care, who had been members of their teams for more than a year (N = 90). Descriptive statistics and "Chi squared" tests were employed. 72%. A high level of agreement on the need for team work (95.23%). They perceived their group cohesiveness as being very low (84.21% affirmed that they encounter problems of cohesiveness). The main statements concerning this lack of cohesiveness were: "lack of common objectives" (25.5%), "intolerance between workers" (20.13%), "work not shared" (19.46%) and "the taking of decisions individually" (19.44%). The main causes given were: lack of support from Management (23.74%) and too little training for team work (21.58%). There is a high degree of conviction that the team work model is the most efficacious way of developing Primary Care. However in three of the four teams questioned, there were serious problems preventing the teams' reaching an adequate level of group cohesiveness.

  19. Relationship between Family Adaptability, Cohesion and Adolescent Problem Behaviors: Curvilinearity of Circumplex Model.

    Science.gov (United States)

    Joh, Ju Youn; Kim, Sun; Park, Jun Li; Kim, Yeon Pyo

    2013-05-01

    The Family Adaptability and Cohesion Evaluation Scale (FACES) III using the circumplex model has been widely used in investigating family function. However, the criticism of the curvilinear hypothesis of the circumplex model has always been from an empirical point of view. This study examined the relationship between adolescent adaptability, cohesion, and adolescent problem behaviors, and especially testing the consistency of the curvilinear hypotheses with FACES III. We used the data from 398 adolescent participants who were in middle school. A self-reported questionnaire was used to evaluate the FACES III and Youth Self Report. According to the level of family adaptability, significant differences were evident in internalizing problems (P = 0.014). But, in externalizing problems, the results were not significant (P = 0.305). Also, according to the level of family cohesion, significant differences were in internalizing problems (P = 0.002) and externalizing problems (P = 0.004). The relationship between the dimensions of adaptability, cohesion and adolescent problem behaviors was not curvilinear. In other words, adolescents with high adaptability and high cohesion showed low problem behaviors.

  20. Anisotropic Failure Strength of Shale with Increasing Confinement: Behaviors, Factors and Mechanism.

    Science.gov (United States)

    Cheng, Cheng; Li, Xiao; Qian, Haitao

    2017-11-15

    Some studies reported that the anisotropic failure strength of shale will be weakened by increasing confinement. In this paper, it is found that there are various types of anisotropic strength behaviors. Four types of anisotropic strength ratio ( S A 1 ) behaviors and three types of anisotropic strength difference ( S A 2 ) behaviors have been classified based on laboratory experiments on nine groups of different shale samples. The cohesion c w and friction angle ϕ w of the weak planes are proven to be two dominant factors according to a series of bonded-particle discrete element modelling analyses. It is observed that shale is more prone to a slight increase of S A 1 and significant increase of S A 2 with increasing confinement for higher cohesion c w and lower to medium friction angle ϕ w . This study also investigated the mechanism of the anisotropic strength behaviors with increasing confinement. Owing to different contributions of c w and ϕ w under different confinements, different combinations of c w and ϕ w may have various types of influences on the minimum failure strength with the increasing confinement; therefore, different types of anisotropic behaviors occur for different shale specimens as the confinement increases. These findings are very important to understand the stability of wellbore and underground tunneling in the shale rock mass, and should be helpful for further studies on hydraulic fracture propagations in the shale reservoir.

  1. Coseismic landslides reveal near-surface rock strength in a high-relief tectonically active setting

    Science.gov (United States)

    Gallen, Sean F.; Clark, Marin K.; Godt, Jonathan W.

    2014-01-01

    We present quantitative estimates of near-surface rock strength relevant to landscape evolution and landslide hazard assessment for 15 geologic map units of the Longmen Shan, China. Strength estimates are derived from a novel method that inverts earthquake peak ground acceleration models and coseismic landslide inventories to obtain material proper- ties and landslide thickness. Aggregate rock strength is determined by prescribing a friction angle of 30° and solving for effective cohesion. Effective cohesion ranges are from 70 kPa to 107 kPa for 15 geologic map units, and are approximately an order of magnitude less than typical laboratory measurements, probably because laboratory tests on hand-sized specimens do not incorporate the effects of heterogeneity and fracturing that likely control near-surface strength at the hillslope scale. We find that strength among the geologic map units studied varies by less than a factor of two. However, increased weakening of units with proximity to the range front, where precipitation and active fault density are the greatest, suggests that cli- matic and tectonic factors overwhelm lithologic differences in rock strength in this high-relief tectonically active setting.

  2. Grain boundary engineering for structure materials of nuclear reactors

    Science.gov (United States)

    Tan, L.; Allen, T. R.; Busby, J. T.

    2013-10-01

    Grain boundary engineering (GBE), primarily implemented by thermomechanical processing, is an effective and economical method of enhancing the properties of polycrystalline materials. Among the factors affecting grain boundary character distribution, literature data showed definitive effect of grain size and texture. GBE is more effective for austenitic stainless steels and Ni-base alloys compared to other structural materials of nuclear reactors, such as refractory metals, ferritic and ferritic-martensitic steels, and Zr alloys. GBE has shown beneficial effects on improving the strength, creep strength, and resistance to stress corrosion cracking and oxidation of austenitic stainless steels and Ni-base alloys.

  3. Grain boundary engineering for structure materials of nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Tan, L., E-mail: tanl@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory (United States); Allen, T.R. [Department of Engineering Physics, University of Wisconsin–Madison (United States); Busby, J.T. [Materials Science and Technology Division, Oak Ridge National Laboratory (United States)

    2013-10-15

    Grain boundary engineering (GBE), primarily implemented by thermomechanical processing, is an effective and economical method of enhancing the properties of polycrystalline materials. Among the factors affecting grain boundary character distribution, literature data showed definitive effect of grain size and texture. GBE is more effective for austenitic stainless steels and Ni-base alloys compared to other structural materials of nuclear reactors, such as refractory metals, ferritic and ferritic–martensitic steels, and Zr alloys. GBE has shown beneficial effects on improving the strength, creep strength, and resistance to stress corrosion cracking and oxidation of austenitic stainless steels and Ni-base alloys.

  4. Spilling over: Partner parenting stress as a predictor of family cohesion in parents of adolescents with developmental disabilities.

    Science.gov (United States)

    Mitchell, Darcy B; Szczerepa, Alexandra; Hauser-Cram, Penny

    2016-01-01

    Family cohesion relates to positive outcomes for both parents and children. Maintaining cohesion may be especially challenging for families of adolescents with developmental disabilities, yet this has been studied infrequently in this group. We investigated cohesion in these families, particularly with respect to partner stress, using the notion of the 'spillover effect' as a model. Adolescents with disabilities and their parents participated. Parents reported on teen adaptive and problem behaviours and on marital satisfaction, parenting stress, and family cohesion. The stress of one partner was tested as a predictor of the quality of family cohesion reported by the other. Adolescent behaviour problems were negative predictors of family cohesion in mothers, and marital satisfaction positively predicted cohesion for both parents. Above other factors, greater partner stress predicted poorer family cohesion for both fathers and mothers. Marital satisfaction acted as a suppressor of this relation. To improve the overall climate of families, care providers should take into consideration individual relationships, including the marital relationship. In addition, the possibility of spillover from one individual to another should be recognized as a factor in family functioning. Family-centred practices are likely to lead to greater feelings of cohesion and overall better individual and family well-being. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Outdoor activities and depressive symptoms in displaced older adults following natural disaster: community cohesion as mediator and moderator.

    Science.gov (United States)

    Chao, Shiau-Fang

    2016-09-01

    This investigation examined whether community cohesion mediates or moderates the relationship between outdoor activities and depressive symptoms in older adults displaced by Typhoon Morakot in Taiwan. This cross-sectional study included 292 adults aged 65 years or older who were relocated to permanent houses after Typhoon Morakot damaged their homes on 8th August 2009. Multiple regression analysis was applied to test the role of community cohesion on the association between outdoor activities and depressive symptoms. The sample of displaced older adults displayed higher prevalence of depressive symptoms than the average for community dwelling older people in Taiwan. Community cohesion fully mediated the relationship between outdoor activities and depressive symptoms. Community cohesion also moderated the relationship between outdoor activities and depressive symptoms. Community cohesion occupies a key role on the link between outdoor activities and depressive symptoms. Participation in outdoor activities was associated positively with community cohesion, while high community cohesion was related negatively to depressive symptoms. Additionally, the benefit of outdoor activities to fewer depressive symptoms only manifested in older adults with high community cohesion. Programs and services should be designed to enhance community cohesion in order to maximize the benefit of outdoor activities to the mental health of displaced older adults after natural disasters.

  6. Give Me Strength.

    Institute of Scientific and Technical Information of China (English)

    维拉

    1996-01-01

    Mort had an absolutely terrible day at the office.Everythingthat could go wrong did go wrong.As he walked home he could beheard muttering strange words to himself:“Oh,give me strength,give me strength.”Mort isn’t asking for the kind of strength thatbuilds strong muscles:he’s asking for the courage or ability to

  7. Spatializing Open Data for the Assessment and the Improvement of Territorial and Social Cohesion

    Science.gov (United States)

    Scorza, F.; Las Casas, G. B.; Murgante, B.

    2016-09-01

    An integrated place-based approach for the improvement of territorial and social cohesion is the new instance for planning disciplines, coming from EU New Cohesion Policies. This paper considers the territorial impact assessment of regional development policies as a precondition in order to develop balanced and effective operative programs at national and regional levels. The contribution of `open data' appears to be mature in order to support this application and in this paper we present a spatial analysis technique for the evaluation of EU funds effects at territorial level, starting from open data by Open Cohesion. The application is focused on internal areas of Basilicata Region: Agri river Valley. A complex contest, where environmental and agricultural traditional vocations conflict with a recent development of oil extraction industries. Conclusions concern further applications and perspectives to improve and support regional development planning considering the exploitation of open data sources and spatial analysis.

  8. Noncontact Cohesive Swimming of Bacteria in Two-Dimensional Liquid Films.

    Science.gov (United States)

    Li, Ye; Zhai, He; Sanchez, Sandra; Kearns, Daniel B; Wu, Yilin

    2017-07-07

    Bacterial swimming in confined two-dimensional environments is ubiquitous in nature and in clinical settings. Characterizing individual interactions between swimming bacteria in 2D confinement will help to understand diverse microbial processes, such as bacterial swarming and biofilm formation. Here we report a novel motion pattern displayed by flagellated bacteria in 2D confinement: When two nearby cells align their moving directions, they tend to engage in cohesive swimming without direct cell body contact, as a result of hydrodynamic interaction but not flagellar intertwining. We further found that cells in cohesive swimming move with higher directional persistence, which can increase the effective diffusivity of cells by ∼3 times as predicted by computational modeling. As a conserved behavior for peritrichously flagellated bacteria, cohesive swimming in 2D confinement may be key to collective motion and self-organization in bacterial swarms; it may also promote bacterial dispersal in unsaturated soils and in interstitial space during infections.

  9. Group cohesion and social support in exercise classes: results from a danish intervention study

    DEFF Research Database (Denmark)

    Christensen, Ulla; Schmidt, Lone; Budtz-Jørgensen, Esben

    2006-01-01

    This study examines the formation of group cohesion and social support in exercise classes among former sedentary adults, participating in a Danish community-based intervention. Furthermore, the aim is to analyze the impact of this process on exercise activity among the participants. A multimethod...... approach was used, analyzing both survey data and 18 personal interviews collected among 87 participants who completed the intervention project. Analysis was performed according to the grounded theory method. The formation of group cohesion was conditioned by the social composition of the group......, the teaching ability by the instructors, and the activity by itself. The cohesive group was characterized by an attitude of mutual support toward exercise activities. This mutual support facilitated development of self-efficacy beliefs among the participants improving their mastery expectation regarding...

  10. Place-based innovation in Cohesion Policy: meeting and measuring the challenges

    Directory of Open Access Journals (Sweden)

    Alys Solly

    2016-01-01

    Full Text Available This paper, prepared in conjunction with the European Union’s Open Days 2015, examines current Cohesion Policy in terms of its place-based logic, a key aspect of the new Smart Specialisation strategy platform. After discussing changing notions of urbanization and governance, which seem to be shifting Cohesion Policy towards a more performance-oriented analysis of its outcomes, the paper focuses on the question of identifying an appropriate set of indicators and measuring framework. It suggests that measurements of Cohesion Policy performance should analyse the outcomes and indicators, as well as the European and national data sources and statistics, through the lens of effectiveness and well-being.

  11. FUNDING COHESION POLICY IN THE EUROPEAN UNION AND ROMANIA DURING 2014 – 2020

    Directory of Open Access Journals (Sweden)

    MARIA VASILESCU

    2016-08-01

    Full Text Available Cohesion policy is one of the most important and complex policy of the European Union, a position clearly derived from the assumed objective of "harmonious development by reducing disparities between the levels of development of the various regions and the backwardness of the least favoured regions or islands". Its unique role in shaping and implementing integrated development strategies, which involve activities in various fields such as education, research and innovation, employment, business environment, infrastructure, environmental protection, climate change and energy efficiency is undeniable. To accomplish these goals cohesion policy is benefiting from its own budget for each Member State in relation to the national objectives of economic and social development and to integration into the Single Internal Market and achieving territorial cohesion

  12. Moisture Content Impact on Mechanical Properties of Selected Cohesive Soils from the Wielkopolskie Voivodeship Southern Part

    Directory of Open Access Journals (Sweden)

    Pezowicz Piotr

    2015-12-01

    Full Text Available Results of investigations of shearing resistance and compressibility of fine-grained cohesive soil from the southern part of the wielkopolskie voivodeship in relation to the increasing moisture content are presented. The analysis of two series of samples, using soil paste for the consistency index of 0.9 and 0.4–0.3 was carried out. The results imply that the increasing moisture content causes a decrease in the angle of shearing resistance and cohesion and is also reflected in the higher compressibility of the soil. It was observed that regardless of the soil consistency, the angle of shearing resistance decreases and the cohesion value and the oedometric modulus of primary (consolidation and secondary compressibility grows with the increase in the clay fraction.

  13. The application of J integral to measure cohesive laws in materials undergoing large scale yielding

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Goutianos, Stergios

    2015-01-01

    We explore the possibility of determining cohesive laws by the J-integral approach for materials having non-linear stress-strain behaviour (e.g. polymers and composites) by the use of a DCB sandwich specimen, consisting of stiff elastic beams bonded to the non-linear test material, loaded with pure...... bending moments. For a wide range of parameters of the non-linear material, the plastic unloading during crack extension is small, resulting in J integral values (fracture resistance) that deviate maximum 15% from the work of the cohesive traction. Thus the method can be used to extract the cohesive laws...... directly from experiments without any presumption about their shape. Finally, the DCB sandwich specimen was also analysed using the I integral to quantify the overestimation of the steady-state fracture resistance obtained using the J integral based method....

  14. Experiences of street harassment and associations with perceptions of social cohesion among women in Mexico City

    Directory of Open Access Journals (Sweden)

    Paola A Campos

    2017-01-01

    Full Text Available Objective. To document the frequency and forms of street harassment and examine the association between street harassment experiences and perceptions of social cohesion. Materials and methods. Baseline survey data collected among women seeking care in public health clinics in Mexico City were used for analysis. Results. Nearly two-thirds (62.8% of women reported experiencing some form of street harassment in the prior month; women with street harassment experiences reported significantly lower perceived social cohesion (b=-0.46; 95%CI:0.69,-0.22. Conclusions. Findings indicate reducing street harassment may have important implications for improving women’s perceived social cohesion and their safety in Mexico City.

  15. Validating Experimental Bedform Dynamics on Cohesive Sand-Mud Beds in the Dee Estuary

    Science.gov (United States)

    Baas, Jaco H.; Baker, Megan; Hope, Julie; Malarkey, Jonathan; Rocha, Renata

    2014-05-01

    Recent laboratory experiments and field measurements have shown that small quantities of cohesive clay, and in particular 'sticky' biological polymers, within a sandy substrate dramatically reduce the development rate of sedimentary bedforms, with major implications for sediment transport rate calculations and process interpretations from the sedimentary record. FURTHER INFORMATION Flow and sediment transport predictions from sedimentary structures found in modern estuaries and within estuarine geological systems are impeded by an almost complete lack of process-based knowledge of the behaviour of natural sediments that consist of mixtures of cohesionless sand and biologically-active cohesive mud. Indeed, existing predictive models are largely based on non-organic cohesionless sands, despite the fact that mud, in pure form or mixed with sand, is the most common sediment on Earth and also the most biologically active interface across a range of Earth-surface environments, including rivers and shallow seas. The multidisciplinary COHBED project uses state-of-the-art laboratory and field technologies to measure the erosional properties of mixed cohesive sediment beds and the formation and stability of sedimentary bedforms on these beds, integrating the key physical and biological processes that govern bed evolution. The development of current ripples on cohesive mixed sediment beds was investigated as a function of physical control on bed cohesion versus biological control on bed cohesion. These investigations included laboratory flume experiments in the Hydrodynamics Laboratory (Bangor University) and field experiments in the Dee estuary (at West Kirby near Liverpool). The flume experiments showed that winnowing of fine-grained cohesive sediment, including biological stabilisers, is an important process affecting the development rate, size and shape of the cohesive bedforms. The ripples developed progressively slower as the kaolin clay fraction in the sandy substrate

  16. Parenthetical Cohesive Explicitness: A Linguistic Approach for a Modified Translation of the Quranic Text

    Directory of Open Access Journals (Sweden)

    Mohammad Amin Hawamdeh

    2015-09-01

    Full Text Available Motivated by the severe criticism the Hilali and Khan (HK Translation of the Holy Quran has received for its too many parenthetical insertions, this study aimed at linguistically realizing how such added pieces of information could be for necessary cohesive explicitness or worthless redundant interpolation. Methodically, the HK translation of the first 8 verses of Chapter 18 (The Cave, Surah Al Kahf of the Holy Quran was selected to be a subject material. A number of 15 instances of explicitation put in parentheses were encountered; they were found to be based upon 23 cohesive (grammatical/lexical relationships and, hence, to be considered as ones of cohesive explicitness. Eventually, such an analysis could be of use for modifying the available translations of the Holy Quran.

  17. Social cohesion and the smoking behaviors of adults living with children.

    Science.gov (United States)

    Alcalá, Héctor E; Sharif, Mienah Z; Albert, Stephanie L

    2016-02-01

    The smoking behavior of adults can negatively impact children through exposure to environmental tobacco smoke and by modeling this unhealthy behavior. Little research has examined the role of the social environment in smoking behaviors of adults living with children. The present study specifically analyzed the relationship between social cohesion and smoking behaviors of adults living with children. Data from the 2009 California Health Interview Survey, a random-digit dial cross-sectional survey of California Adults, were used. Adults living with children reported their levels of social cohesion and smoking behaviors (N=13,978). Logistic regression models were used to predict odds of being a current smoker or living in a household in which smoking was allowed, from social cohesion. Overall, 13% of the sample was current smokers and 3.74% lived in households in which smoking was allowed. Logistic regression models showed that each one-unit increase in social cohesion is associated with reduced odds of being a current smoker (AOR=0.92; 95% CI=0.85-0.99) and reduced odds of living in a household in which smoking is allowed (AOR=0.84; 95% CI=0.75-0.93), after controlling for sociodemographic characteristics. Among adults living with children, higher social cohesion is associated with a lower likelihood of both being and smoker and living in a home where smoking is allowed. Thus, future research is needed to better understand mechanisms that explain the relationship between social cohesion and smoking-related behavior in order to prevent smoking-related health consequences and smoking initiation among children and adults. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Corporal Punishment and Child Aggression: Ethnic-Level Family Cohesion as a Moderator.

    Science.gov (United States)

    Lee, Yoona; Watson, Malcolm W

    2017-04-01

    Ethnicity has been examined as a putative moderator between parents' use of corporal punishment and children's externalizing behaviors. Yet, the reasons for this potential ethnic-level moderator have not been fully examined. The primary objective of this study was to examine whether the effect of corporal punishment on aggression is ethnic-specific using major racial groups inside and outside the U.S. samples and how the mean levels of cohesion in family relationships as found in different ethnic groups moderate the association between mothers' use of corporal punishment and children's aggression. A total of 729 mothers who had children aged 7 to 13 years were sampled from five ethnic groups (i.e., European American, African American, Hispanic American, Korean, and Chinese). Several hypotheses were tested to examine the moderating effect of ethnic-level, family cohesion on the relation of corporal punishment to children's aggression. As expected, the mean level of family cohesion was significantly different across ethnicities. Consistent results across parallel multilevel and fixed effect models showed that high corporal punishment was associated with more aggression in all ethnicities, but there was a significant variation in the association across ethnicities, and the variation was explained by ethnic-level family cohesion. There were weaker associations between corporal punishment and child aggression among ethnic groups with high family cohesion and stronger associations among ethnic groups with low family cohesion. Ethnic/cultural variation in this study emphasizes the importance of understanding family environment of diverse ethnic groups when evaluating the influence of corporal punishment on child behavior in different ethnic/cultural contexts.

  19. Investigation on the cohesive silt/clay-particle sediment via the coupled CFD-DEM simulations

    Science.gov (United States)

    Xu, S.; Sun, H.; Sun, R.

    2017-12-01

    Sedimentation of silt/clay particles happens ubiquitously in nature and engineering field. There have been abundant studies focusing on the settling velocity of the cohesive particles, while studies on the sediment deposited from silt/clay irregular particles, including the vertical concentration profile of sediment and the various forces among the deposited particles are still lacking. This paper aims to investigate the above topics by employing the CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) simulations. In this work, we simulate the settling of the mono- and poly- dispersed silt/clay particles and mainly study the characteristics of the deposited cohesive sediment. We use the bonded particles to simulate the irregular silt/clay aggregates at the initial state and utilize the van der Waals force for all micro-particles to consider the cohesive force among silt/clay particles. The interparticle collision force and the fluid-particle interaction forces are also considered in our numerical model. The value of the mean structural density of cohesive sediment obtained from simulations is in good agreement with the previous research, and it is obviously smaller than no-cohesive sediment because of the existence of the silt/clay flocs. Moreover, the solid concentration of sediment increases with the growth of the depth. It is because the silt/clay flocs are more easily to break up due to the gradually increased submerged gravity of the deposited particles along the depth. We also obtain the noncontacted cohesive force and contact force profiles during the sedimentation and the self-weight consolidation process. The study of the concentration profile and the forces among silt/clay sediment will help to give an accurate initial condition for calculating the speed of the reconsolidation process by employing the artificial loads, which is necessary for practical designs of the land reclamation projects.

  20. A community based intervention program to enhance neighborhood cohesion: The Learning Families Project in Hong Kong.

    Science.gov (United States)

    Shen, Chen; Wan, Alice; Kwok, Lit Tung; Pang, Sally; Wang, Xin; Stewart, Sunita M; Lam, Tai Hing; Chan, Sophia S

    2017-01-01

    Neighborhood cohesion, which refers to the extent of the connectedness and solidarity among residents in a community or neighborhood, is an important determinant of human health. To enhance neighborhood cohesion, the "Learning Families Project" was developed with a series of intervention programs in Kwun Tong in Hong Kong, a district with low neighborhood cohesion. This project, based on the social ecological model, provided a platform for neighbors to learn, communicate and interact with each other. This quasi-experimental study included two nearby government subsidized low rent housing estates separated by busy main roads. One served as the intervention (Tsui Ping (South) Estate) and one as the control (Shun Tin Estate) estate. The intervention included promotion, resident training and learning programs, embodied by a series of community activities such as talks, day camp, thematic activities and horticulture class. Baseline (before the programs) and follow-up (one year after the programs) surveys were conducted both in the intervention and control estate to assess the impact of the programs on neighborhood cohesion. The number of residents who completed both the baseline and follow-up surveys was 502 in the intervention estate and 476 in the control estate. Neighborhood cohesion significantly improved in the intervention group after the programs (Cohen effect size d: 0.15). Compared with the control group, the improvements in closeness of the neighborhood and trust in neighbors were significantly greater in the intervention group (Cohen effect size d: 0.13 and 0.14, respectively). This brief intervention program using a quasi-experimental study design increased neighborhood cohesion in a low rent housing estate. ClinicalTrials.gov NCT02851667.

  1. Leader Behaviors, Group Cohesion, and Participation in a Walking Group Program.

    Science.gov (United States)

    Izumi, Betty T; Schulz, Amy J; Mentz, Graciela; Israel, Barbara A; Sand, Sharon L; Reyes, Angela G; Hoston, Bernadine; Richardson, Dawn; Gamboa, Cindy; Rowe, Zachary; Diaz, Goya

    2015-07-01

    Less than half of all U.S. adults meet the 2008 Physical Activity Guidelines. Leader behaviors and group cohesion have been associated with increased participation or adherence in sports team and exercise class settings. Physical activity interventions in community settings that encompass these factors may enhance intervention adherence. The purpose of this study is to examine the impact of Community Health Promoter leader behaviors and group cohesion on participation in a walking group intervention among racially/ethnically diverse adults in low to moderate-income communities in Detroit, Michigan. Data for the current study were drawn from the Walk Your Heart to Health (WYHH) data set. WYHH was a multisite cluster RCT with a lagged intervention and outcome measurements at baseline and 4, 8, and 32 weeks. Pooled survey data from both intervention arms were used for the current study. Data were analyzed between August 2013 and October 2014. A total of 603 non-Hispanic black, non-Hispanic white, and Hispanic adults across five cohorts that began the 32-week WYHH intervention between March 2009 and October 2011. The intervention was a 32-week walking group program hosted by community- and faith-based organizations and facilitated by Community Health Promoters. Walking groups met three times per week for 90 minutes per session. To promote participation in or adherence to WYHH, Community Health Promoters used evidence-based strategies to facilitate group cohesion. Group members assumed increasing leadership responsibility for facilitating sessions over time. Participation in WYHH as measured by consistency of attendance. Community Health Promoter leader behaviors were positively associated with participation in WYHH. Social but not task cohesion was significantly associated with consistent participation. Social cohesion may mediate the relationship between leader behaviors and walking group participation. Providing leaders with training to build socially cohesive groups

  2. Improving decision speed, accuracy and group cohesion through early information gathering in house-hunting ants.

    Science.gov (United States)

    Stroeymeyt, Nathalie; Giurfa, Martin; Franks, Nigel R

    2010-09-29

    Successful collective decision-making depends on groups of animals being able to make accurate choices while maintaining group cohesion. However, increasing accuracy and/or cohesion usually decreases decision speed and vice-versa. Such trade-offs are widespread in animal decision-making and result in various decision-making strategies that emphasize either speed or accuracy, depending on the context. Speed-accuracy trade-offs have been the object of many theoretical investigations, but these studies did not consider the possible effects of previous experience and/or knowledge of individuals on such trade-offs. In this study, we investigated how previous knowledge of their environment may affect emigration speed, nest choice and colony cohesion in emigrations of the house-hunting ant Temnothorax albipennis, a collective decision-making process subject to a classical speed-accuracy trade-off. Colonies allowed to explore a high quality nest site for one week before they were forced to emigrate found that nest and accepted it faster than emigrating naïve colonies. This resulted in increased speed in single choice emigrations and higher colony cohesion in binary choice emigrations. Additionally, colonies allowed to explore both high and low quality nest sites for one week prior to emigration remained more cohesive, made more accurate decisions and emigrated faster than emigrating naïve colonies. These results show that colonies gather and store information about available nest sites while their nest is still intact, and later retrieve and use this information when they need to emigrate. This improves colony performance. Early gathering of information for later use is therefore an effective strategy allowing T. albipennis colonies to improve simultaneously all aspects of the decision-making process--i.e. speed, accuracy and cohesion--and partly circumvent the speed-accuracy trade-off classically observed during emigrations. These findings should be taken into account

  3. Psychobiological Assessment and Enhancement of Team Cohesion and Psychological Resilience in ROTC Cadets Using a Virtual-Reality Team Cohesion Test

    Science.gov (United States)

    2017-06-01

    processing and transcribing of audio recordings. This audio data will provide measures of group cohesion, group roles , communication efficiency, etc. 4...or other products from the project made an impact or are likely to make an impact on the base of knowledge, theory , and research in the principal...Recruitment and Retention: Thus far, recruitment has consisted of civilians. We are recruiting both male and female same- sex triads. Recruitment

  4. The Bottom Boundary Layer.

    Science.gov (United States)

    Trowbridge, John H; Lentz, Steven J

    2018-01-03

    The oceanic bottom boundary layer extracts energy and momentum from the overlying flow, mediates the fate of near-bottom substances, and generates bedforms that retard the flow and affect benthic processes. The bottom boundary layer is forced by winds, waves, tides, and buoyancy and is influenced by surface waves, internal waves, and stratification by heat, salt, and suspended sediments. This review focuses on the coastal ocean. The main points are that (a) classical turbulence concepts and modern turbulence parameterizations provide accurate representations of the structure and turbulent fluxes under conditions in which the underlying assumptions hold, (b) modern sensors and analyses enable high-quality direct or near-direct measurements of the turbulent fluxes and dissipation rates, and (c) the remaining challenges include the interaction of waves and currents with the erodible seabed, the impact of layer-scale two- and three-dimensional instabilities, and the role of the bottom boundary layer in shelf-slope exchange.

  5. The Bottom Boundary Layer

    Science.gov (United States)

    Trowbridge, John H.; Lentz, Steven J.

    2018-01-01

    The oceanic bottom boundary layer extracts energy and momentum from the overlying flow, mediates the fate of near-bottom substances, and generates bedforms that retard the flow and affect benthic processes. The bottom boundary layer is forced by winds, waves, tides, and buoyancy and is influenced by surface waves, internal waves, and stratification by heat, salt, and suspended sediments. This review focuses on the coastal ocean. The main points are that (a) classical turbulence concepts and modern turbulence parameterizations provide accurate representations of the structure and turbulent fluxes under conditions in which the underlying assumptions hold, (b) modern sensors and analyses enable high-quality direct or near-direct measurements of the turbulent fluxes and dissipation rates, and (c) the remaining challenges include the interaction of waves and currents with the erodible seabed, the impact of layer-scale two- and three-dimensional instabilities, and the role of the bottom boundary layer in shelf-slope exchange.

  6. Measuring the impact of spatial network layout on community social cohesion: a cross-sectional study.

    Science.gov (United States)

    Cooper, Crispin H V; Fone, David L; Chiaradia, Alain J F

    2014-04-11

    There is now a substantial body of research suggesting that social cohesion, a collective characteristic measured by the levels of trust, reciprocity and formation of strong social bonds within communities, is an important factor in determining health. Of particular interest is the extent to which factors in the built environment facilitate, or impede, the development of social bonds. Severance is a characteristic of physical environments which is hypothesized to inhibit cohesion. In the current study we test a number of characteristics of spatial networks which could be hypothesized to relate either to severance, or directly to community cohesion. Particular focus is given to our most promising variable for further analysis (Convex Hull Maximum Radius 600 m). In the current study we analysed social cohesion as measured at Enumeration District level, aggregated from a survey of 10,892 individuals aged 18 to 74 years in the Caerphilly Health and Social Needs Cohort Study, 2001. In a data mining process we test 16 network variables on multiple scales. The variable showing the most promise is validated in a test on an independent data set. We then conduct a multivariate regression also including Townsend deprivation scores and urban/rural status as predictor variables for social cohesion. We find convex hull maximum radius at a 600 m scale to have a small but highly significant correlation with social cohesion on both data sets. Deprivation has a stronger effect. Splitting the analysis by tertile of deprivation, we find that the effect of severance as measured by this variable is strongest in the most deprived areas. A range of spatial scales are tested, with the strongest effects being observed at scales that match typical walking distances. We conclude that physical connectivity as measured in this paper has a significant effect on social cohesion, and that our measure is unlikely to proxy either deprivation or the urban/rural status of communities. Possible

  7. Team cohesion and ethnic-cultural identity in adolescent migrant athletes

    DEFF Research Database (Denmark)

    Morela, Eleftheria; Hatzigeorgiadis, Antonis; Kouli, Olga

    2013-01-01

    The purpose of this study was to examine the role of sport participation in the social integration of adolescents with non-dominant ethnic and cultural backgrounds. In particular, this study investigated the relationship between team cohesion and ethnic-cultural identity. Participants were 83 young...... migrant athletes (mean age 15.60 years). Participants completed the Ethnic/Cultural Identity Salience Questionnaire and the Youth Sport Environment Questionnaire. Regression analyses showed that cohesion negatively predicted feelings of fringe and lack of interaction. Our findings suggest that sport...

  8. Cohesive traction-separation relations for plate tearing under mixed mode loading

    DEFF Research Database (Denmark)

    Andersen, R. G.; Woelke, P. B.; Nielsen, K. L.

    2018-01-01

    The present study investigates a sequence of failure events related to steady-state tearing of large-scale ductile plates by employing the micro-mechanics based Gurson-Tvergaard-Needleman (GTN) model. The fracture process in front of an advancing crack is approximated by a series of 2D plane strain...... finite element models to facilitate a comprehensive study of mixed mode fracture behavior as well as a parameter study of the cohesive energy and tractions involved in the process. The results from the conducted GTN model simulations are used to define cohesive zone models suitable for plate tearing...

  9. Identification of parameters of cohesive elements for modeling of adhesively bonded joints of epoxy composites

    Directory of Open Access Journals (Sweden)

    Kottner R.

    2013-12-01

    Full Text Available Adhesively bonded joints can be numerically simulated using the cohesive crack model. The critical strain energy release rate and the critical opening displacement are the parameters which must be known when cohesive elements in MSC.Marc software are used. In this work, the parameters of two industrial adhesives Hunstman Araldite 2021 and Gurit Spabond 345 for bonding of epoxy composites are identified. Double Cantilever Beam (DCB and End Notched Flexure (ENF test data were used for the identification. The critical opening displacements were identified using an optimization algorithm where the tests and their numerical simulations were compared.

  10. Guidelines for Applying Cohesive Models to the Damage Behaviour of Engineering Materials and Structures

    CERN Document Server

    Schwalbe, Karl-Heinz; Cornec, Alfred

    2013-01-01

    This brief provides guidance for the application of cohesive models to determine damage and fracture in materials and structural components. This can be done for configurations with or without a pre-existing crack. Although the brief addresses structural behaviour, the methods described herein may also be applied to any deformation induced material damage and failure, e.g. those occurring during manufacturing processes. The methods described are applicable to the behaviour of ductile metallic materials and structural components made thereof. Hints are also given for applying the cohesive model to other materials.

  11. Modelling the double cantilever beam test with bending moments by using bilinear discontinuous cohesive laws

    DEFF Research Database (Denmark)

    Valvo, Paolo S.; Sørensen, Bent F.; Toftegaard, Helmuth Langmaack

    2015-01-01

    A theoretical model of the double cantilever beam tests with bending moments (DCB-UBM) is presented. The specimen is modelled as the assemblage of two laminated beams connected by a cohesive interface. It is assumed that the traction-separation laws – i.e. the relationships between the interfacial...... the cohesive law parameters from experiments. Experimental tests have been conducted on glass fibre reinforced specimens under pure mode I and II loading conditions. The predictions of the theoretical model turn out to be in very good agreement with the experimental results....

  12. [Adaptation of the MSCI for the measurement of cohesion in Spanish young soccer players].

    Science.gov (United States)

    García Quinteiro, Eva María; Rodríguez Casal, Mauro; Andrade, Elena M; Arce, Constantino

    2006-08-01

    This work describes the Spanish adaptation and studies the psychometric properties of Yukelson, Weinberg, and Jackson's Multidimensional Sport Cohesion Instrument (MSCI) with a sample of 173 soccer players. The Spanish version is composed of 22 items grouped in four factors: quality of teamwork (performance aspects), attraction to the group, valued roles and quality of teamwork (interpersonal relationships), that accounted for 53.30% of the total variance. Reliability coefficients (Cronbach's Alphas) for the factors ranged from .84 (factor 1) to .56 (factor 4). Suggestions are made for future research on the validity of the scale, mainly in terms of convergence with other multidimensional measures of sport cohesion.

  13. [A measure of team cohesion in sport. Spanish adaptation of Group Environment Questionnaire (GEQ)].

    Science.gov (United States)

    Iturbide, Luis María; Elosua, Paula; Yanes, Félix

    2010-08-01

    The aim of this work was to adapt the Group Environment Questionnaire (GEQ) to Spanish. Judgmental procedures were used to assess the linguistic and cultural equivalence of the versions. Psychometric procedures were used in the operational phase of the study. The normative sample comprised 924 sportsmen/sportswomen from 75 teams. The GEQ scale showed suitable indexes of internal consistency and a bidimensional structure based on two factors of the cohesion model, the Task component and the Social component. In addition, a positive relation between team-performance and the Task component of team cohesion was observed. Overall, the results supported the Spanish version of the GEQ.

  14. Active cell-matrix coupling regulates cellular force landscapes of cohesive epithelial monolayers

    Science.gov (United States)

    Zhao, Tiankai; Zhang, Yao; Wei, Qiong; Shi, Xuechen; Zhao, Peng; Chen, Long-Qing; Zhang, Sulin

    2018-03-01

    Epithelial cells can assemble into cohesive monolayers with rich morphologies on substrates due to competition between elastic, edge, and interfacial effects. Here we present a molecularly based thermodynamic model, integrating monolayer and substrate elasticity, and force-mediated focal adhesion formation, to elucidate the active biochemical regulation over the cellular force landscapes in cohesive epithelial monolayers, corroborated by microscopy and immunofluorescence studies. The predicted extracellular traction and intercellular tension are both monolayer size and substrate stiffness dependent, suggestive of cross-talks between intercellular and extracellular activities. Our model sets a firm ground toward a versatile computational framework to uncover the molecular origins of morphogenesis and disease in multicellular epithelia.

  15. TERRITORIAL COHESION AND LOCAL DEVELOPMENT USING EUROPEAN STRUCTURAL AND COHESION FUNDS AT THE LEVEL OF GROWTH POLES – CASE STUDY GROWTH POLE BRASOV

    Directory of Open Access Journals (Sweden)

    Aida Petronela CATANA

    2015-08-01

    Full Text Available The growth poles were established in Romania in 2008 as centers for urban development in compliance with European and national policies and they include an urban nucleus and its rural surroundings.  According to the legal framework, for each of the growth poles an Integrated Development Plan should be adopted as basis for European Structural and Cohesion Funds investments. This is a new document in addition to local development plans/strategies of the local communities or counties and regional development plans. From another point of view, the growth poles are representing teritorial units which have to assure territorial cohesion for its urban and rural administrative units. Into this respect, there are different spatial planning documents which have to be followed by the territorial and administrative units, according to the Romanian legislation. Beyond these, there are rules and compulsory criterias for accessing European Structural and Cohesion funds the problems being faced by the associations established by local communities in order to manage the growth poles’s areas. Taking into account all these, we may say that growth poles are the crossing points for different policies translated into plans and operational programmes’s criterias for getting ESC Funds.

  16. Anisotropic Concrete Compressive Strength

    DEFF Research Database (Denmark)

    Gustenhoff Hansen, Søren; Jørgensen, Henrik Brøner; Hoang, Linh Cao

    2017-01-01

    When the load carrying capacity of existing concrete structures is (re-)assessed it is often based on compressive strength of cores drilled out from the structure. Existing studies show that the core compressive strength is anisotropic; i.e. it depends on whether the cores are drilled parallel...

  17. High strength ferritic alloy

    International Nuclear Information System (INIS)

    1977-01-01

    A high strength ferritic steel is specified in which the major alloying elements are chromium and molybdenum, with smaller quantities of niobium, vanadium, silicon, manganese and carbon. The maximum swelling is specified for various irradiation conditions. Rupture strength is also specified. (U.K.)

  18. Photon strength functions

    International Nuclear Information System (INIS)

    Bergqvist, I.

    1976-01-01

    Methods for extracting photon strength functions are briefly discussed. We follow the Brink-Axel approach to relate the strength functions to the giant resonances observed in photonuclear work and summarize the available data on the E1, E2 and M1 resonances. Some experimental and theoretical problems are outlined. (author)

  19. Interviewing to Understand Strengths

    Science.gov (United States)

    Hass, Michael R.

    2018-01-01

    Interviewing clients about their strengths is an important part of developing a complete understanding of their lives and has several advantages over simply focusing on problems and pathology. Prerequisites for skillfully interviewing for strengths include the communication skills that emerge from a stance of not knowing, developing a vocabulary…

  20. Problems of matter-antimatter boundary layers

    International Nuclear Information System (INIS)

    Lehnert, B.

    1975-01-01

    This paper outlines the problems of the quasi-steady matter-antimatter boundary layers discussed in Klein-Alfven's cosmological theory, and a crude model of the corresponding ambiplasma balance is presented: (i) at interstellar particle densities, no well-defined boundary layer can exist in presence of neutral gas, nor can such a layer be sustained in an unmagnetized fully ionized ambiplasma. (ii) Within the limits of applicability of the present model, sharply defined boundary layers are under certain conditions found to exist in a magnetized ambiplasma. Thus, at beta values less than unity, a steep pressure drop of the low-energy components of matter and antimatter can be balanced by a magnetic field and the electric currents in the ambiplasma. (iii) The boundary layer thickness is of the order of 2x 0 approximately 10/BT 0 sup(1/4) meters, where B is the magnetic field strength in MKS units and T 0 the characteristic temperature of the low-energy components in the layer. (Auth.)

  1. Minnesota County Boundaries - lines

    Data.gov (United States)

    Minnesota Department of Natural Resources — Minnesota county boundaries derived from a combination of 1:24,000 scale PLS lines, 1:100,000 scale TIGER, 1:100,000 scale DLG, and 1:24,000 scale hydrography lines....

  2. Boundary-Object Trimming

    DEFF Research Database (Denmark)

    Bossen, Claus; Jensen, Lotte Groth; Udsen, Flemming Witt

    2014-01-01

    implementation, which also coupled the work of medical secretaries more tightly to that of other staff, and led to task drift among professions. Medical secretaries have been relatively invisible to health informatics and CSCW, and we propose the term ‘boundary-object trimming’ to foreground and conceptualize...

  3. Minnesota County Boundaries

    Data.gov (United States)

    Minnesota Department of Natural Resources — Minnesota county boundaries derived from a combination of 1:24,000 scale PLS lines, 1:100,000 scale TIGER, 1:100,000 scale DLG, and 1:24,000 scale hydrography lines....

  4. Boundaries of the universe

    CERN Document Server

    Glasby, John S

    2013-01-01

    The boundaries of space exploration are being pushed back constantly, but the realm of the partially understood and the totally unknown is as great as ever. Among other things this book deals with astronomical instruments and their application, recent discoveries in the solar system, stellar evolution, the exploding starts, the galaxies, quasars, pulsars, the possibilities of extraterrestrial life and relativity.

  5. Texture, Textuality and Political Discourse: A Study of Lexical Cohesion in Nigeria's President Goodluck Jonathan's Inaugural Address, May, 2011

    Science.gov (United States)

    Enyi, Amaechi Uneke; Chitulu, Mark Ononiwu

    2015-01-01

    This study, entitled, "Texture and textuality in Political Discourse: A Study of Cohesive Devices in President Goodluck Jonathan's Inaugural Address-May, 2011" was an analysis of the lexical cohesive devices employed by Nigeria's President Goodluck Jonathan in crafting his May, 2011's Presidential Inaugural Address (PIA). Guided by the…

  6. Social cohesiveness and absenteeism - The relationship between characteristics of employees and short-term absenteeism within an organization

    NARCIS (Netherlands)

    Sanders, K; Nauta, A

    2004-01-01

    This study tries to explain the relationship between characteristics of the employees (e.g., gender and working hours) and short-term absenteeism by examining the social cohesiveness of a team. Hypotheses are formulated concerning gender and working hours of employees, social cohesiveness, and

  7. Diversity and social cohesion : the case of Jane-Finch, a highly diverse lower-income Toronto neighbourhood

    NARCIS (Netherlands)

    Ahmadi, D.

    2017-01-01

    Diversity has increasingly emerged as the core focus of many studies concerning factors impacting on social cohesion. Various scholars have concluded that diversity is detrimental to cohesion. Most of this research, however, draws generalisations based upon quantitative data and fails to account

  8. Self-Esteem among Vietnamese American Adolescents: The Role of Self-Construal, Family Cohesion, and Social Support

    Science.gov (United States)

    Lam, Brian Trung

    2005-01-01

    This prospective study examined whether interdependent self-construal (collectivism), independent self-construal (individualism), family cohesion, and social support would predict levels of self-esteem among Vietnamese American adolescents. Standardized self-report measures of family cohesion, social support, and self-esteem, as well as a measure…

  9. Neighborhood Social Cohesion and Sleep Outcomes in the Native Hawaiian and Pacific Islander National Health Interview Survey.

    Science.gov (United States)

    Young, Marielle C; Gerber, Monica W; Ash, Tayla; Horan, Christine M; Taveras, Elsie M

    2018-05-16

    Native Hawaiians and Pacific Islanders (NHPIs) have the lowest attainment of healthy sleep duration among all racial and ethnic groups in the United States. We examined associations of neighborhood social cohesion with sleep duration and quality. Cross-sectional analysis of 2,464 adults in the NHPI National Health Interview Survey (2014). Neighborhood social cohesion was categorized as a continuous and categorical variable into low (15) according to tertiles of the distribution of responses. We used multinomial logistic regression to examine the adjusted odds ratio of short and long sleep duration relative to intermediate sleep duration. We used binary logistic regression for dichotomous sleep quality outcomes. Sleep outcomes were modeled as categorical variables. 40% of the cohort reported short (9 hours) duration. Mean (SE, range) social cohesion score was 12.4 units (0.11, 4-16) and 23% reported low social cohesion. In multivariable models, each 1 SD decrease in neighborhood social cohesion score was associated with higher odds of short sleep duration (OR: 1.14, 95% CI: 1.02, 1.29). Additionally, low social cohesion was associated with increased odds of short sleep duration (OR: 1.53, 95% CI: 1.10, 2.13). No associations between neighborhood social cohesion and having trouble falling or staying asleep and feeling well rested were found. Low neighborhood social cohesion is associated with short sleep duration in NHPIs.

  10. Responses to Forces Influencing Cohesion as a Function of Player Status and Level of Male Varsity Basketball Competition.

    Science.gov (United States)

    Gruber, Joseph J.; Gray, Gary R.

    1982-01-01

    A study analyzed team cohesion perceptions of 515 male varsity basketball players (10 to 22 years of age) to determine if factors influencing team cohesion were a function of competitive intensity or of the importance of individual players to their team. Players with the most game playing time were more satisfied than those with less playing time.…

  11. [Effects of Korean proficiency and parent-child cohesion on self-esteem and acculturation among children from multicultural families].

    Science.gov (United States)

    Kim, Mi Ye; Lim, Ji Young; Chung, Grace H

    2012-12-01

    There is evidence that parent-child cohesion is a potentially influential factor in children's self-esteem and acculturation. However, no research to date has examined cohesion with parents as a potential pathway between Korean proficiency and self-esteem or acculturation among children from multicultural families. This study was done to address these limitations by examining whether and to what extent cohesion with parents mediated the effect of Korean proficiency on self-esteem and acculturation among children from multicultural families. Data were collected from a sample of 138 mothers and their children living in Seoul, Daegu, Kyungi province, and Kyungpook province. Multiple regression analysis was used to examine the relationships between the variables of interest. Mediation effects of cohesion with parents were tested by following the procedure recommended by Baron and Kenny (1986). Cohesion with parents partially mediated the relationship between Korean proficiency and self-esteem. For children's acculturation, the effect of Korean proficiency was partially mediated through father-child cohesion. Mother-child cohesion completely mediated the relationship between Korean proficiency and acculturation. These findings suggest that to help children from multicultural families experiencing difficulties with self-esteem or acculturation, it might be useful to develop programs that are aimed at strengthen cohesion with parents.

  12. Factors associated with low neighborhood cohesion among women living with HIV impacted by social-structural inequities in British Columbia.

    Science.gov (United States)

    Closson, Kalysha; Palmer, Alexis K; Collins, Alexandra B; Salters, Kate; Zhang, Wendy; Montaner, Julio S G; Hogg, Robert S; Parashar, Surita

    2018-03-01

    Built and social environments, including one's perception of their environment, are important determinants of health. The intersection of gender and HIV status may complicate the role of neighborhood cohesion in safety, personal well-being, and health outcomes for populations impacted by social and structural inequities. Among women in particular, social cohesion within the neighborhood they reside in may have a greater influence on health outcomes compared to their male counterparts. We sought to examine perception of neighborhood cohesion (validated scale with a range 0-100, with higher scores indicating higher perceived neighborhood cohesion) among women living with HIV, impacted by social-structural inequities, receiving combination antiretroviral therapy, and enrolled in the Longitudinal Investigations into Supportive Ancillary health services (LISA) study in British Columbia, Canada. Cross-sectional data on neighborhood cohesion and socio-demographic data were collected in an interviewer-administered survey. Of the 1,000 LISA participants interviewed, 908 (including 249 women and 659 men) had complete data for the variables of interest. At the bivariate level, women had worse perceived neighborhood cohesion scores compared to men (median: 56 [95% CI: 44-66] vs. 60 [95% CI: 47-71]). Multivariable model results indicated that for women living with HIV in our sample, greater neighborhood cohesion scores were positively associated with stable housing (β coefficient = 7.85; 95% CI: 3.61, 12.10, p perceptions of neighborhood cohesion.

  13. Cohesion and the Social Construction of Meaning in the Essays of Filipino College Students Writing in L2 English

    Science.gov (United States)

    Castro, Carolyn D.

    2004-01-01

    This study compares the degree of cohesion and coherence in the essays written by thirty Filipino college freshmen and analyzes how the social construction of meaning was made evident in their writing. Results showed that low, mid and highly rated essays were comparable in grammatical cohesive device use. Lexical repetition and use of synonyms…

  14. Social cohesiveness and absenteeism : the relationship between characteristics of employees and short-term absenteeism within an organization

    NARCIS (Netherlands)

    Sanders, K.; Nauta, A.

    2004-01-01

    This article tries to explain the relationship between characteristics of the employees as gender and working hours, and short-term absenteeism by examining the social cohesiveness of a team. Hypotheses are formulated concerning gender and working hours of employees, social cohesiveness, and

  15. Alcohol Use Severity Among Adult Hispanic Immigrants: Examining the Roles of Family Cohesion, Social Support, and Gender.

    Science.gov (United States)

    Cano, Miguel Ángel; Sánchez, Mariana; Rojas, Patria; Ramírez-Ortiz, Daisy; Polo, Katherine L; Romano, Eduardo; De La Rosa, Mario

    2018-03-21

    This study examined (a) the direct association of family cohesion on alcohol use severity among adult Hispanic immigrants; (b) the indirect association of family cohesion on alcohol use severity via social support; and (c) if gender moderates the direct and indirect associations between family cohesion and alcohol use severity. Mediation and moderation analyses were conducted on a cross-sectional sample of 411 (men = 222, women = 189) participants from Miami-Dade, Florida. Findings indicate that higher family cohesion was directly associated with higher social support and lower alcohol use severity. Higher social support was also directly associated with lower alcohol use severity. Additionally, family cohesion had an indirect association with alcohol use severity via social support. Moderation analyses indicated that gender moderated the direct association between family cohesion and alcohol use severity, but did not moderate the indirect association. Some potential clinical implications may be that strengthening family cohesion may enhance levels of social support, and in turn, lower alcohol use severity among adult Hispanic immigrants. Furthermore, strengthening family cohesion may be especially beneficial to men in efforts to lower levels of alcohol use severity.

  16. Alumina-fluorapatite composite coating deposited by atmospheric plasma spraying: An agent of cohesion between bone and prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbel, Halima Feki, E-mail: ghorbel.halima@yahoo.fr [LCI, Ecole Nationale d' Ingénieurs de Sfax “ENIS”, Soukra 1173-3038, Sfax (Tunisia); LERMPS, Université de Technologie de Belfort-Montbeliard “UTBM”, Belfort 90010 (France); Guidara, Awatef [LCI, Ecole Nationale d' Ingénieurs de Sfax “ENIS”, Soukra 1173-3038, Sfax (Tunisia); Danlos, Yoan [LERMPS, Université de Technologie de Belfort-Montbeliard “UTBM”, Belfort 90010 (France); Bouaziz, Jamel [LCI, Ecole Nationale d' Ingénieurs de Sfax “ENIS”, Soukra 1173-3038, Sfax (Tunisia); Coddet, Christian [LERMPS, Université de Technologie de Belfort-Montbeliard “UTBM”, Belfort 90010 (France)

    2017-02-01

    In order to remedy the poor biological and tribological properties of 316 L stainless steel (SS), plasma sprayed bio-ceramic coatings have been widely investigated. In the present study, a small amount of fluorapatite (Fap) was introduced into alumina in order to enhance its bioactivity. The powder feedstock was sprayed on 316 L substrate by Atmospheric Plasma Spraying (APS) technology. The roughness profiles and average roughness values were determined using 3D profilometry. The cross sectional morphologies of the coatings were examined by scanning electron microscopy (SEM). Adhesive strength, micro-hardness and tribological properties were also examined. Experimental results revealed that Al{sub 2}O{sub 3}/Fap coating showed a good microhardness property revealing that the calcium aluminates were quite effective in improving the Fap mechanical behavior. The tribological characteristics of both alumina and alumina-Fap coating were also compared to those of classical hydroxyapatite (Hap) coatings as reported in the literature. The main finding of this work was that Fap coating can contribute to the cohesion between bone and prostheses and thus ensure a more durable and reliable prostheses. - Highlights: • This research addresses tissue engineering and novel biomaterials consisting of combination of Al{sub 2}O{sub 3} and Fap. • The addition of Fap to alumina results in higher coating porosity, which may be beneficial for the mechanical fixture by bone ingrowth. • Adhesion strength of the alumina ceramic coating is improved by the Fap addition • The presence of CaO in the synthesized Fap may help in improving the mechanical resistance through to formation of the calcium aluminates.

  17. Alumina-fluorapatite composite coating deposited by atmospheric plasma spraying: An agent of cohesion between bone and prostheses

    International Nuclear Information System (INIS)

    Ghorbel, Halima Feki; Guidara, Awatef; Danlos, Yoan; Bouaziz, Jamel; Coddet, Christian

    2017-01-01

    In order to remedy the poor biological and tribological properties of 316 L stainless steel (SS), plasma sprayed bio-ceramic coatings have been widely investigated. In the present study, a small amount of fluorapatite (Fap) was introduced into alumina in order to enhance its bioactivity. The powder feedstock was sprayed on 316 L substrate by Atmospheric Plasma Spraying (APS) technology. The roughness profiles and average roughness values were determined using 3D profilometry. The cross sectional morphologies of the coatings were examined by scanning electron microscopy (SEM). Adhesive strength, micro-hardness and tribological properties were also examined. Experimental results revealed that Al 2 O 3 /Fap coating showed a good microhardness property revealing that the calcium aluminates were quite effective in improving the Fap mechanical behavior. The tribological characteristics of both alumina and alumina-Fap coating were also compared to those of classical hydroxyapatite (Hap) coatings as reported in the literature. The main finding of this work was that Fap coating can contribute to the cohesion between bone and prostheses and thus ensure a more durable and reliable prostheses. - Highlights: • This research addresses tissue engineering and novel biomaterials consisting of combination of Al 2 O 3 and Fap. • The addition of Fap to alumina results in higher coating porosity, which may be beneficial for the mechanical fixture by bone ingrowth. • Adhesion strength of the alumina ceramic coating is improved by the Fap addition • The presence of CaO in the synthesized Fap may help in improving the mechanical resistance through to formation of the calcium aluminates

  18. Conformal boundary loop models

    International Nuclear Information System (INIS)

    Jacobsen, Jesper Lykke; Saleur, Hubert

    2008-01-01

    We study a model of densely packed self-avoiding loops on the annulus, related to the Temperley-Lieb algebra with an extra idempotent boundary generator. Four different weights are given to the loops, depending on their homotopy class and whether they touch the outer rim of the annulus. When the weight of a contractible bulk loop x≡q+q -1 element of (-2,2], this model is conformally invariant for any real weight of the remaining three parameters. We classify the conformal boundary conditions and give exact expressions for the corresponding boundary scaling dimensions. The amplitudes with which the sectors with any prescribed number and types of non-contractible loops appear in the full partition function Z are computed rigorously. Based on this, we write a number of identities involving Z which hold true for any finite size. When the weight of a contractible boundary loop y takes certain discrete values, y r ≡([r+1] q )/([r] q ) with r integer, other identities involving the standard characters K r,s of the Virasoro algebra are established. The connection with Dirichlet and Neumann boundary conditions in the O(n) model is discussed in detail, and new scaling dimensions are derived. When q is a root of unity and y=y r , exact connections with the A m type RSOS model are made. These involve precise relations between the spectra of the loop and RSOS model transfer matrices, valid in finite size. Finally, the results where y=y r are related to the theory of Temperley-Lieb cabling

  19. Influence of dry cohesion on the micro- and macro-mechanical properties of dense polydisperse powders & grains

    Science.gov (United States)

    Kievitsbosch, Robert; Smit, Hendrik; Magnanimo, Vanessa; Luding, Stefan; Taghizadeh, Kianoosh

    2017-06-01

    Understanding how cohesive granular materials behave is of interest for many industrial applications, such as pharmaceutical or food and civil engineering. Models of the behaviour of granular materials on the microscopic scale can be used to obtain macroscopic continuum relations by a micro-macro transition approach. The Discrete Element Method (DEM) is used to inspect the influence of cohesion on the micro and macro behaviour of granular assemblies by using an elasto-plastic cohesive contact model. Interestingly, we observe that frictional samples prepared with different cohesion values show a significant difference in pressure and coordination number in the jammed regime; the differences become more pronounced when packings are closer to the jamming density, i.e. the lowest density where the system is mechanically stable. Furthermore, we observe that cohesion has an influence on the jamming density for frictional samples, but there is no influence on the jamming density for frictionless samples.

  20. Reconsidering the boundary conditions for a dynamic, transient mode I crack problem

    KAUST Repository

    Leise, Tanya

    2008-11-01

    A careful examination of a dynamic mode I crack problem leads to the conclusion that the commonly used boundary conditions do not always hold in the case of an applied crack face loading, so that a modification is required to satisfy the equations. In particular, a transient compressive stress wave travels along the crack faces, moving outward from the loading region on the crack face. This does not occur in the quasistatic or steady state problems, and is a special feature of the transient dynamic problem that is important during the time interval immediately following the application of crack face loading. We demonstrate why the usual boundary conditions lead to a prediction of crack face interpenetration, and then examine how to modify the boundary condition for a semi-infinite crack with a cohesive zone. Numerical simulations illustrate the resulting approach.

  1. Cohesive cracked-hinge model for simulation of fracture in one-way slabs on grade

    DEFF Research Database (Denmark)

    Skar, Asmus; Poulsen, Peter Noe; Olesen, John Forbes

    2017-01-01

    Numerical analysis of slab on grade structures subjected to mechanical loads is a complex matter often requiring computationally expensive models. In order to develop a simplified and general concept for non-linear analysis of slab on grade structures, this paper presents a cohesive cracked-hinge...

  2. A prospective study of group cohesiveness in therapeutic horticulture for clinical depression.

    Science.gov (United States)

    Gonzalez, Marianne Thorsen; Hartig, Terry; Patil, Grete Grindal; Martinsen, Egil W; Kirkevold, Marit

    2011-04-01

    This study aimed to assess changes in psychological distress and social participation in adults diagnosed with clinical depression during and after participating in a therapeutic horticulture programme, and to investigate if the changes covaried with levels of group cohesiveness during the intervention. An intervention with a single-group design was repeated with different samples in successive years (pooled n = 46). In each year, five groups of 3-7 participants went through the intervention. Data were collected before, twice during, and immediately after a 12-week therapeutic horticulture programme, as well as at 3-months' follow up. Mental health assessments included the Beck Depression Inventory, the State Subscale of Spielberger State-Trait Anxiety Inventory, the Positive Affect Scale from the Positive and Negative Affect Scale, the Perceived Stress Scale, and the Therapeutic Factors Inventory-Cohesiveness Scale. The analysis of the pooled data confirmed significant beneficial change in all mental health variables during the intervention. Change from baseline in depression severity persisted at 3-months' follow up. Increased social activity after the intervention was reported for 38% of the participants. The groups quickly established strong cohesiveness, and this continued to increase during the intervention. The average level of group cohesiveness correlated positively, but not significantly, with change in all mental health outcome variables. © 2011 The Authors. International Journal of Mental Health Nursing © 2011 Australian College of Mental Health Nurses Inc.

  3. An Evaluation of Mi Familia No Fuma: Family Cohesion and Impact on Secondhand Smoking

    Science.gov (United States)

    Law, Jon; Kelly, Michael; Garcia, Pema; Taylor, Thom

    2010-01-01

    Background: Family cohesion may be a factor to prevent exposure of Hispanics in United States to secondhand smoke. Purpose: The purpose of this study was to evaluate one permutation of Mi Familia No Fuma (MFNF) and its resulting outputs or proximal client outcomes. Methods: MFNF is an approach to secondhand smoke prevention, using family cohesion…

  4. Study on Lexical Cohesion in English and Persian Research Articles (A Comparative Study)

    Science.gov (United States)

    Mirzapour, Fatemeh; Ahmadi, Maryam

    2011-01-01

    The present study aims to analyze comparatively English and Persian research articles (Linguistics, Literature, and Library and Information disciplines) in terms of number and degree of utilization of sub-types of lexical cohesion in order to appreciate textualization processes in the two languages concerned. The study analyzes 60 research…

  5. A Computer Text Analysis of Four Cohesion Devices in English Discourse by Native and Nonnative Writers.

    Science.gov (United States)

    Reid, Joy

    1992-01-01

    In a contrastive rhetoric study of nonnative English speakers, 768 essays written in English by native speakers of Arabic, Chinese, Spanish, and English were examined using the Writer's Workbench program to determine whether distinctive, quantifiable differences in the use of 4 cohesion devices existed among the 4 language backgrounds. (Author/LB)

  6. Genre-dependent interaction of coherence and lexical cohesion in written discourse

    NARCIS (Netherlands)

    Berzlánovich, I.; Redeker, G.

    2012-01-01

    We investigate the interaction between coherence and lexical cohesion in expository and persuasive texts using seven encyclopedia texts and seven fundraising letters. We describe genre structure in terms of genre-specific moves and coherence structure with Rhetorical Structure Theory. For lexical

  7. Explaining Teacher Turnover: School Cohesion and Intrinsic Motivation in Los Angeles

    Science.gov (United States)

    Fuller, Bruce; Waite, Anisah; Irribarra, David Torres

    2016-01-01

    Lifting achievement in many schools depends on reducing the exit of effective teachers. We examine the extent to which teacher perceptions of school cohesion and intrinsic motivators stemming from two theoretical traditions contribute to the intent to leave one's school. We find that elementary teachers report higher levels of organizational…

  8. Emotional Intelligence, Communication Competence, and Student Perceptions of Team Social Cohesion

    Science.gov (United States)

    Troth, Ashlea C.; Jordan, Peter J.; Lawrence, Sandra A.

    2012-01-01

    Students generally report poor experiences of group work in university settings. This study examines whether individual student perceptions of team social cohesion are determined by their level of emotional intelligence (EI) and whether this relationship is mediated by their communication skills. Business students (N = 273) completed the 16-item…

  9. Kinetic theory for dilute cohesive granular gases with a square well potential

    NARCIS (Netherlands)

    Takada, Satoshi; Saitoh, K.; Hayakawa, Hisao

    2016-01-01

    We develop the kinetic theory of dilute cohesive granular gases in which the attractive part is described by a square well potential. We derive the hydrodynamic equations from the kinetic theory with the microscopic expressions for the dissipation rate and the transport coefficients. We check the

  10. Kinetic theory for dilute cohesive granular gases with a square well potential.

    Science.gov (United States)

    Takada, Satoshi; Saitoh, Kuniyasu; Hayakawa, Hisao

    2016-07-01

    We develop the kinetic theory of dilute cohesive granular gases in which the attractive part is described by a square well potential. We derive the hydrodynamic equations from the kinetic theory with the microscopic expressions for the dissipation rate and the transport coefficients. We check the validity of our theory by performing the direct simulation Monte Carlo.

  11. Linking Social Cohesion and Gender to Intrapersonal and Interactional Empowerment: Support and New Implications for Theory

    Science.gov (United States)

    Peterson, N. Andrew; Lowe, John B.; Aquilino, Mary L.; Schneider, John E.

    2005-01-01

    Empowerment is a social-action process through which people gain greater control, efficacy, and social justice. One way to develop empowerment is through active, meaningful participation in community groups and activities. Social cohesion is an emerging construct that expands the notion of community participation to include elements such as shared…

  12. Shell Nouns as Cohesive Devices in Published and ESL Student Writing

    Science.gov (United States)

    Aktas, Rahime Nur; Cortes, Viviana

    2008-01-01

    This paper analyzes the use of a special type of unspecific noun, called "shell nouns" [Hunston, S., & Francis, G. (1999). "Pattern grammar". Amsterdam: Benjamins; Schmid, H. (2000). "English abstract nouns as conceptual shells: From corpus to cognition". Berlin: Walter de Gruyter], which are frequently used as cohesive devices, in the written…

  13. Neighborhoods and Mental Health: Exploring Ethnic Density, Poverty, and Social Cohesion among Asian Americans and Latinos

    Science.gov (United States)

    Hong, Seunghye; Zhang, Wei; Walton, Emily

    2014-01-01

    This study examines the associations of neighborhood ethnic density and poverty with social cohesion and self-rated mental health among Asian Americans and Latinos. Path analysis is employed to analyze data from the 2002–2003 National Latino and Asian American Study (NLAAS) and the 2000 U.S. Census (N=2095 Asian Americans living in N=259 neighborhoods; N=2554 Latinos living in N=317 neighborhoods). Findings reveal that neighborhood ethnic density relates to poor mental health in both groups. Social cohesion partially mediates that structural relationship, but is positively related to ethnic density among Latinos and negatively related to ethnic density among Asian Americans. Although higher neighborhood poverty is negatively associated with mental health for both groups, the relationship does not hold in the path models after accounting for social cohesion and covariates. Furthermore, social cohesion fully mediates the association between neighborhood poverty and mental health among Latinos. This study highlights the necessity of reconceptualizing existing theories of social relationships to reflect complex and nuanced mechanisms linking neighborhood structure and mental health for diverse racial and ethnic groups. PMID:24769491

  14. The Relationship between Organizational Citizenship Behavior, Group Cohesiveness and Workplace Deviance Behavior of Turkish Teachers

    Science.gov (United States)

    Apaydin, Çigdem; Sirin, Hüseyin

    2016-01-01

    This study aims to develop a structural model for organizational citizenship behavior, group cohesiveness and workplace deviance behavior. The study group consists of 639 Turkish teachers working in primary and secondary public schools. In the study, the "Organizational Citizenship Behavior Scale" and the "Group Cohesiveness…

  15. SOLO: a meiotic protein required for centromere cohesion, coorientation, and SMC1 localization in Drosophila melanogaster.

    Science.gov (United States)

    Yan, Rihui; Thomas, Sharon E; Tsai, Jui-He; Yamada, Yukihiro; McKee, Bruce D

    2010-02-08

    Sister chromatid cohesion is essential to maintain stable connections between homologues and sister chromatids during meiosis and to establish correct centromere orientation patterns on the meiosis I and II spindles. However, the meiotic cohesion apparatus in Drosophila melanogaster remains largely uncharacterized. We describe a novel protein, sisters on the loose (SOLO), which is essential for meiotic cohesion in Drosophila. In solo mutants, sister centromeres separate before prometaphase I, disrupting meiosis I centromere orientation and causing nondisjunction of both homologous and sister chromatids. Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages. SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin. The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

  16. The preparation, physicochemical properties, and the cohesive energy of liquid sodium containing titanium nanoparticles

    International Nuclear Information System (INIS)

    Saito, Jun-ichi; Itami, Toshio; Ara, Kuniaki

    2012-01-01

    Liquid sodium containing titanium nanoparticles (LSnanop) of 10-nm diameter was prepared by dispersing titanium nanoparticles (2 at.% Ti) into liquid sodium with the addition of stirring and ultrasonic sound wave. The titanium nanoparticles themselves were prepared by the vapor deposition method. This new liquid metal, LSnanop, shows a remarkable stability due to the Brownian motion of nanoparticles in liquid sodium medium. In addition, the difference of measured heat of reaction to water between this LSnanop and liquid sodium indicates the existence of cohesive energy between the liquid sodium medium and dispersed titanium nanoparticles. The origin of the cohesive energy, which serves to stabilize this new liquid metal, was explained by the model of screened nanoparticles in liquid sodium. In this model, negatively charged nanoparticles with transferred electrons from liquid sodium are surrounded by the positively charged screening shell, which may inhibit the gathering of nanoparticles by the “Coulombic repulsion coating.” The atomic volume of LSnanop shows the shrinkage from the linear law, which also suggests the existence of cohesive energy. The viscosity of LSnanop is almost the same as that of liquid sodium. This behavior was explained by the Einstein equation. The surface tension of LSnanop is 17 % larger than that of liquid sodium. The cohesive energy and the negative adsorption may be responsible to this increase. Titanium nanoparticles in liquid sodium seem to be free from the Coulomb fission. This new liquid metal containing nanoparticles suggests the possibility to prepare various stable suspensions with new properties.

  17. Auto consolidated cohesive sediments erosion; Erosion des sediments cohesifs en autoconsolidation

    Energy Technology Data Exchange (ETDEWEB)

    Ternat, F

    2007-02-15

    Pollutants and suspended matters of a river can accumulate into the sedimentary column. Once deposited, they are submitted to self-weight consolidation processes, ageing and burying, leading to an increase of their erosion resistance. Pollutant fluxes can be related to sedimentary fluxes, determined by threshold laws. In this work, an erosion threshold model is suggested by introducing a cohesion force into the usual force balance. A model of cohesion is developed on the basis of interactions between argillaceous cohesive particles (clays), particularly the Van der Waals force, whose parameterization is ensured by means of granulometry and porosity. Artificial erosion experiments were performed in a recirculating erosion flume with natural cored sediments where critical shear stress measurements were performed. Other analyses provided granulometry and porosity. The results obtained constitute a good database for the literature. The model is then applied to the experimental conditions and gives good agreement with measurements. An example of the accounting for self-weight consolidation processes is finally suggested, before finishing on a Mohr like diagram dedicated to soft cohesive sediment erosion. (author)

  18. Questioning territorial cohesion: (Un)equal access to services of general interest

    Czech Academy of Sciences Publication Activity Database

    Malý, Jiří

    -, August 2016 (2016), s. 1-21 ISSN 1056-8190 Institutional support: RVO:68145535 Keywords : territorial cohesion * services of general interest * accessibility * spatial justice * Czech Republic Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.272, year: 2016 http://onlinelibrary.wiley.com/doi/10.1111/pirs.12250/full

  19. Is social cohesion relevant to a city in the global South?

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

    This article investigates the relevance of international framings of social cohesion and collective efficacy, which have largely ... an ethnographic study conducted in Khayelitsha township in the Western Cape, where a major internationally funded and conceptualised ... the global South? A case study of Khayelitsha township ...

  20. Education for Social Cohesion Attempts in Lebanon: Reflections on the 1994 and 2010 Education Reforms

    Science.gov (United States)

    Shuayb, Maha

    2016-01-01

    Following the end of the Lebanese civil war, education was put forward as a major means for rebuilding Lebanon and promoting social cohesion and unity. A huge education development plan was launched in 1994 culminating in a new national curriculum in 1997 and the production of new textbooks. Although the quality of education improved in public…

  1. Relative importance of cohesion and adhesion for sensory stickiness of semisolid foods

    NARCIS (Netherlands)

    Dunnewind, B.; Janssen, A.M.; Vliet, T. van; Weenen, H.

    2004-01-01

    The relative importance of cohesion and adhesion for sensory stickness of semisolid foods was investigated using a texture analyzers. Products included commercial mayon-naises, custard desserts and warm sauces which varied in apparent viscosity between 0.3 and 18.3 Pa.s. It was observed that the

  2. Cohesive Zone Model Based Numerical Analysis of Steel-Concrete Composite Structure Push-Out Tests

    Directory of Open Access Journals (Sweden)

    J. P. Lin

    2014-01-01

    Full Text Available Push-out tests were widely used to determine the shear bearing capacity and shear stiffness of shear connectors in steel-concrete composite structures. The finite element method was one efficient alternative to push-out testing. This paper focused on a simulation analysis of the interface between concrete slabs and steel girder flanges as well as the interface of the shear connectors and the surrounding concrete. A cohesive zone model was used to simulate the tangential sliding and normal separation of the interfaces. Then, a zero-thickness cohesive element was implemented via the user-defined element subroutine UEL in the software ABAQUS, and a multiple broken line mode was used to define the constitutive relations of the cohesive zone. A three-dimensional numerical analysis model was established for push-out testing to analyze the load-displacement curves of the push-out test process, interface relative displacement, and interface stress distribution. This method was found to accurately calculate the shear capacity and shear stiffness of shear connectors. The numerical results showed that the multiple broken lines mode cohesive zone model could describe the nonlinear mechanical behavior of the interface between steel and concrete and that a discontinuous deformation numerical simulation could be implemented.

  3. The Economics of MOOCs and Their Interrelationship to Competitiveness and Cohesiveness: The Case of Israel

    Science.gov (United States)

    BenDavid-Hadar, Iris

    2015-01-01

    Higher education contributes to state competitiveness via human capital development that provides future returns to the economy through increases in labour productivity. Additionally, higher education is an infrastructure for future state-level social cohesiveness. Those countries where the education system produces more equitable outcomes are…

  4. The application of J integral to measure cohesive laws under large-scale yielding

    DEFF Research Database (Denmark)

    Goutianos, Stergios; Sørensen, Bent F.

    2016-01-01

    A method is developed to obtain the mode I cohesive law of elastic-plastic materials using a Double Cantilever Beam sandwich specimen loaded with pure bending moments. The approach is based on the validity of the J integral for materials having a non-linear stress-strain relationship without...

  5. Bearing Capacity of Footings on Thin Layer of Sand on Soft Cohesive Soil

    DEFF Research Database (Denmark)

    Philipsen, J.; Sørensen, Carsten S.

    2004-01-01

    This paper contains the results of some numerical calculations performed with the aim to determine the bearing capacities of footings placed on a thin layer of sand underlain by soft cohesive soil. During the last 30-35 years different analytical and empirical calculation methods for this situation...... prepared model tests made in laboratories....

  6. Too Many Friends: Social Integration, Network Cohesion and Adolescent Depressive Symptoms

    Science.gov (United States)

    Falci, Christina; McNeely, Clea

    2009-01-01

    Using a nationally representative sample of adolescents, we examine associations among social integration (network size), network cohesion (alter-density), perceptions of social relationships (e.g., social support) and adolescent depressive symptoms. We find that adolescents with either too large or too small a network have higher levels of…

  7. Experiments and discrete element simulation of the dosing of cohesive powders in a simplified geometry

    NARCIS (Netherlands)

    Imole, Olukayode Isaiah; Krijgsman, Dinant; Weinhart, Thomas; Magnanimo, Vanessa; Chavez Montes, Bruno E.; Ramaioli, Marco; Luding, Stefan

    2016-01-01

    We perform experiments and discrete element simulations on the dosing of cohesive granular materials in a simplified geometry. The setup is a canister box where the powder is dosed out through the action of a constant-pitch coil feeder connected to a motor. A dosing step consists of a rotation

  8. Flocculation and consolidation of cohesive sediments under the influence of coagulant and flocculant

    NARCIS (Netherlands)

    Ibanez Sanz, M.E.

    2018-01-01

    This thesis focuses on the coagulation and flocculation processes of cohesive sediments under the influence of polyelectrolyte. For this study clay particles and anionic and cationic flocculants were used. The influence of the shear stresses on the flocculation demonstrated that the shear stress is

  9. University Teaching and Social Cohesion in the Age of AIDS: A South African Case Study

    Science.gov (United States)

    Lesko, Nancy

    2007-01-01

    In the context of ongoing social divisions, lack of coherent leadership by government, and even divisiveness over medical advances and public health mandates, how might universities respond? What university actions can support "social cohesion" in a society splintered by class, race, gender, colonial legacies, the history of apartheid,…

  10. Experimental Characterization and Cohesive Laws for Delamination of Off-Axis GFRP Laminates

    DEFF Research Database (Denmark)

    Lindgaard, Esben; Bak, Brian Lau Verndal

    2015-01-01

    This work experimentally characterizes mixed mode delamination in glass fibre reinforced polymer laminates taking into account the influence of the off-axis angle between the lamina orientation and the crack growth direction on the fracture properties. Thus, providing a cohesive law that enables...... analysis of 3D models in which mixed mode crack growth within laminates having anisotropic fracture properties takes place....

  11. Teachers as Agents of Sustainable Peace, Social Cohesion and Development: Theory, Practice & Evidence

    Science.gov (United States)

    Novelli, Mario; Sayed, Yusuf

    2016-01-01

    This paper presents a "peace with social justice" framework for analysing the role of teachers as agents of sustainable peace, social cohesion and development and applies this to research evidence from Pakistan, Uganda, Myanmar and South Africa. The paper draws on evidence from a recently completed UNICEF and ESRC funded project on…

  12. The Use of Cohesive Markers in Narratives by Children with Williams Syndrome

    Science.gov (United States)

    Jones, Nancy Elizabeth

    2013-01-01

    This study examined how children and adolescents with Williams syndrome (WS; ages 8 years, 0 months [8;0]-14;5) used referential devices (determiners and pronouns), tense, and connectives to create cohesion in oral narratives based on a storybook compared to typically developing mentally and chronologically age-matched children. WS children used…

  13. Team cohesion and ethnic-cultural identity in adolescent migrant athletes

    NARCIS (Netherlands)

    Morela, Eleftheria; Hatzigeorgiadis, Antonis; Kouli, Olga; Elbe, Anne-Marie; Sanchez, Xavier

    The purpose of this study was to examine the role of sport participation in the social integration of adolescents with non-dominant ethnic and cultural backgrounds. In particular, this study investigated the relationship between team cohesion and ethnic-cultural identity. Participants were 83 young

  14. Parent-child cohesion, friend companionship and left-behind children's emotional adaptation in rural China.

    Science.gov (United States)

    Zhao, Jingxin; Liu, Xia; Wang, Meifang

    2015-10-01

    Using cross-sectional data from rural left-behind children aged 10-17 years in the Henan Province of China, the present study examined the roles of father-child cohesion, mother-child cohesion, and friend companionship in emotional adaptation (loneliness, depression, and life satisfaction) among children left behind by both of their rural-to-urban migrant parents compared to those with only a migrating father. The results indicated that the children with two migrating parents were disadvantaged according to their demonstration of depression but not in loneliness or life satisfaction. Both parent-child cohesion and friend companionship were directly associated with, to varying extents, the left-behind children's emotional outcomes. Moreover, friend companionship moderated the association between father-child cohesion and emotional outcomes among children with two migrating parents, but the moderating effects of friend companionship did not exist among children with only a migrating father. The implications of these findings for interventions directed at left-behind children are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Language-in-Education Policies, Immigration and Social Cohesion in Catalonia: The Case of Vic

    Science.gov (United States)

    Edwards, Catrin Wyn

    2016-01-01

    This paper analyses the language-in-education policies implemented to integrate international immigrants into the Catalan language community in Vic, Catalonia. It focuses on the Catalan Government's "Languages and Social Cohesion Plan" (LIC) plan, Vic city council's local education plans, which were adopted as part of LIC plan, and the…

  16. The regional and urban policy of the European Union : Cohesion, results-orientation and smart specialisation

    NARCIS (Netherlands)

    McCann, Philip

    2015-01-01

    The regional and urban development policy of the European Union, or more precisely, EU Cohesion Policy, is undergoing change. This development is driven by the enormous transformations in European regions and by shifts in thinking and analysis. The issues raised by the changes to regional and urban

  17. Relationships between cohesion, collective efficacy and performance in professional basketball teams: an examination of mediating effects.

    Science.gov (United States)

    Heuzé, Jean-Philippe; Raimbault, Nicolas; Fontayne, Paul

    2006-01-01

    The main aim of this study was to examine mediating effects in the relationships between cohesion, collective efficacy and performance in professional basketball teams. A secondary aim was to examine the correlates of collective efficacy in a professional sport. A total of 154 French and foreign professional players completed French or English versions of questionnaires about cohesion and collective efficacy. Two composite measures of individual performance were used (pre- and post-performance). Individual-level analyses were performed. Regression analyses supported two mediating relationships with collective efficacy as a mediator of the pre-performance - Group integration-task relationship, and Group integration-task as a mediator of the pre-performance - collective efficacy relationship. Statistical analyses indicated that neither Group integration-task nor collective efficacy was a better mediator in the relationship between pre-performance and the other group variables. Results also revealed positive relationships between three dimensions of cohesion (i.e. Individual attractions to the group-task, Group integration-task, Group integration-social) and collective efficacy. These findings suggest that in professional basketball teams, staff members should look after athletes who perform at a lower or below their usual level because their performances might lead them into a downward cohesion - collective efficacy spiral. Staff members should also develop a high quality of group functioning, both on and off the basketball court, given its relationship with collective efficacy.

  18. Coaches' Immediacy Behaviors as Predictors of Athletes' Perceptions of Satisfaction and Team Cohesion

    Science.gov (United States)

    Turman, Paul D.

    2008-01-01

    This study sought to determine whether coaches' immediacy behaviors serve as predictors of athletes' satisfaction and team cohesion levels. Participants included 307 male and female high school athletes who completed measures assessing perceptions of their coaches' verbal and nonverbal immediacy behaviors, as well as their own levels of…

  19. Team Creativity: The Effects of Perceived Learning Culture, Developmental Feedback and Team Cohesion

    Science.gov (United States)

    Joo, Baek-Kyoo; Song, Ji Hoon; Lim, Doo Hun; Yoon, Seung Won

    2012-01-01

    This study investigates the influence of perceived learning culture, developmental feedback and team cohesion on team creativity. The results showed that the demographic variables, the three antecedents and their interactions explained 41 per cent of variance in team creativity. Team creativity was positively correlated with a higher level of…

  20. Multiculturalism and Community Cohesion in Britain: The Case of Arab Minority

    Directory of Open Access Journals (Sweden)

    Mohamed Benitto

    2015-11-01

    Full Text Available This article falls within the scope of debate about 'Community Cohesion' in Britain. Community cohesion is at the centre of public policy initiated in response to the urban disturbances in northern towns. Many official reports pointed out that lack of community cohesion is an element jeopardizing security and safe coexistence. In this sense, this article explores hindrances to intergroup coexistence, given that this issue is the main concern in this pluralist society since the attacks in London in July, 7, 2005, through the study of intercultural relations between Arab minority of London and mainstream society in Britain. This research adopts an approach which aims to contribute to the understanding of the reasons hampering community cohesion through juxtaposition of viewpoints of both the minority and majority group. The originality of this approach lies in the fact that it tackles the issue of integration from two sided points of view: the point of the majority group and the point of view of the minority group; unlike most literature on intergroup relations which basically focus on the integration of the minority and its daptation to the dominant culture.