bluuebunny/crossref_metadata_2025_split huggingface dataset:
A non‐linear interface element for 3D mesoscale analysis of brick‐masonry structures
Authors: Macorini L. , Izzuddin B. A. 
Published: October 2010

AbstractThis paper presents a novel interface element for the geometric and material non‐linear analysis of unreinforced brick‐masonry structures. In the proposed modelling approach, the blocks are modelled using 3D continuum solid elements, whereas the mortar and brick–mortar interfaces are modelled by means of the 2D non‐linear interface element. This enables the representation of any 3D arrangement for brick‐masonry, accounting for the in‐plane stacking mode and the through‐thickness geometry, and importantly it allows the investigation of both the in‐plane and the out‐of‐plane responses of unreinforced masonry panels. A co‐rotational approach is employed for the interface element, which shifts the treatment of geometric non‐linearity to the level of discrete entities, and enables the consideration of material non‐linearity within a simplified local framework employing first‐order kinematics. In this respect, the internal interface forces are modelled by means of elasto‐plastic material laws based on work‐softening plasticity and employing multi‐surface plasticity concepts. Following the presentation of the interface element formulation details, several experimental–numerical comparisons are provided for the in‐plane and out‐of‐plane static behaviours of brick‐masonry panels. The favourable results achieved demonstrate the accuracy and the significant potential of using the developed interface element for the non‐linear analysis of brick‐masonry structures under extreme loading conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Finite element implementation of a kinetic model of dynamic strain aging in aluminum–magnesium alloys
Authors: Zhang F. , Bower A. F. , Curtin W. A. 
Published: October 2010

AbstractSoare and Curtin (Acta Mater. 2008; 56:4091–4101, 4046–4061) have recently developed a model of dynamic strain aging in solute‐strengthened alloys. Their constitutive law describes time‐dependent solute strengthening using rate equations that can be calibrated using atomistic simulations. In this paper, their material model is incorporated into a continuum finite element simulation, with a view to completing a multi‐scale method for predicting the formability of solute‐strengthened alloys. The Soare–Curtin model is first re‐formulated as a state‐variable constitutive law, which is suitable for finite element computations. An efficient numerical procedure is then developed to track the strength distribution of aging mobile and forest dislocations in the solid during deformation. The method is tested by simulating the behavior of a 3D aluminum–magnesium alloy tensile specimen subjected to uniaxial loading at constant nominal strain rate. The model predicts the influence of strain rate on the steady‐state flow stress of Al–Mg alloys, but no Portevin–Le Châtelier bands or serrated flow were observed in any of our simulations, and the influence of strain rate on tensile ductility is not predicted correctly. The reasons for this behavior and possible resolutions are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Isogeometric analysis of nearly incompressible solids
Authors: Taylor R. L. 
Published: October 2010

AbstractThis paper describes the use of isogeometric methods to solve problems in finite deformation solid mechanics in which compressible and nearly incompressible behavior may be encountered. The work is based on a three‐field variational structures in which displacements, mean stress and volume effects are independently approximated. Using this approach and tensor product NURBS approximations it is shown how the solution can be conducted in a standard approach, where main variables are organized at nodes (control points). This leads to an efficient procedure to solve large problems of a general form without the need to develop special solution strategies. The approach is demonstrated on some standard test problems. Copyright © 2010 John Wiley & Sons, Ltd.
An edge‐based smoothed finite element method (ES‐FEM) using 3‐node triangular elements for 3D non‐linear analysis of spatial membrane structures
Authors: Zhang Zhi‐Qian , Liu G. R. 
Published: October 2010

AbstractAn edge‐based smoothed finite element method using 3‐node triangular membrane elements (ES‐FEM‐T3) is proposed to analyze three‐dimensional (3D) spatial membrane structures under large deflection, rotation, and strain. In our 3D formulation, co‐rotational local coordinate systems associated with the edge‐based smoothing domains are constructed. Edge‐based gradient smoothing for the spatial membrane structure is performed in global Cartesian coordinate system and transformed into the co‐rotational local coordinate system. The smoothed strain and stress can then be properly evaluated in the co‐rotational local coordinate system after the elimination of the rigid body motions simply by coordinates transformation. Explicit time integration scheme is used to compute the transient response of the 3D spatial membrane structure to time‐domain excitations, and the dynamic relaxation method is employed to obtain steady‐state solutions. The numerical results demonstrate that the proposed method produces much better solution accuracy and computational efficiency than the standard FEM using T3 membrane element. Copyright © 2010 John Wiley & Sons, Ltd.
SGBEM–FEM coupling for analysis of cracks in 3D anisotropic media
Authors: Rungamornrat Jaroon , Mear Mark E. 
Published: October 2010

AbstractA weakly singular symmetric Galerkin boundary element method (SGBEM) is coupled with the standard finite element method (FEM) in order to establish an accurate and efficient numerical technique for analysis of fractures in three‐dimensional, anisotropic, linearly elastic media. In the strategy, the weakly singular SGBEM developed by Rungamornrat and Mear (textitInt. J. Solids Struct. 2008; 45:1283–1301; Comput. Methods Appl. Mech. Engrg 2008; 197:4319–4332) is utilized to model a small‐scale region containing the crack while the (possibly large and complex) compliment region is treated by the FEM. The coupled technique exploits the positive features of both methods; the SGBEM proves to be a convenient and highly accurate method for obtaining mixed‐mode stress intensity factors along the crack front, whereas the FEM is very efficient for modeling large‐scale problems in the absence of cracks. An important aspect of the formulation and implementation of the technique is that continuity of displacement and traction across the interface between the SGBEM and FEM regions is enforced in a weak sense. This allows the two regions (one modeled by the SGBEM and the other by the FEM) to be discretized independently without the need for the resulting meshes to conform on the interface separating the regions, and this flexibility in the discretization process leads to a significant reduction in the modeling effort. To demonstrate the utility and accuracy of the technique, several boundary value problems involving both embedded and surface breaking cracks are treated, and it is shown that the coupled technique yields highly accurate stress intensity factors that exhibit only a slight dependence upon mesh refinement. Copyright © 2010 John Wiley & Sons, Ltd.
A partition of unity finite element method for simulating non‐linear debonding and matrix failure in thin fibre composites
Authors: Radtke F. K. F. , Simone A. , Sluys L. J. 
Published: October 2010

AbstractWe present a partition of unity finite element method for simulating non‐linear debonding and matrix failure in thin fibre composites. Fibres are superimposed on a background mesh without meshing them. The constitutive behaviour of the matrix material, the fibre material and the fibre–matrix bond can be independently defined. A concise derivation of the discrete governing equations is given for two classes of continuum damage models describing the matrix material. A non‐linear bond‐slip law including debonding and fibre pull‐out behaviour is used. Several examples illustrate the potential of the proposed approach. Copyright © 2010 John Wiley & Sons, Ltd.
An element‐free analysis of mechanical and thermal buckling of functionally graded conical shell panels
Authors: Zhao X. , Liew K. M. 
Published: October 2010

AbstractThis paper presents a mechanical and thermal buckling analysis of metal and ceramic functionally graded conical shell panels using the element‐free kp‐Ritz method. The formulation is based on the first‐order shear deformation shell theory, which accounts for the transverse shear strains and rotary inertia, and mesh‐free kernel particle functions are employed to approximate the two‐dimensional displacement fields. The effective material properties of the functionally graded conical shell panels are assumed to be smooth and continuous through their thickness direction, and are determined according to a power‐law distribution of the volume fractions of their constituents. Convergence studies are performed in terms of the number of nodes, and comparisons between the current solutions and those reported in the literature are provided to verify the accuracy of the proposed method. Three types of functionally graded conical shell panels, Al/ZrO2, SUS304/Si3N4, and Al2O3/Ti−6Al−4V are selected for study, and the effects of the volume fraction, boundary condition, semi‐vertex angle, length‐to‐thickness ratio, and temperature‐dependent material properties on the buckling strength are discussed in detail. Copyright © 2010 John Wiley & Sons, Ltd.
The myths of coping with loss in undergraduate psychiatric nursing books
Authors: Holman E. Alison , Perisho Jennifer , Edwards Ada , Mlakar Natalie 
Published: October 2010

AbstractNurses often help patients cope with loss. Recent research has cast doubt on the validity of early theories about loss and grief commonly taught to nurses. We systematically examined the accuracy of information on coping with loss presented in 23 commonly used undergraduate psychiatric nursing books. All 23 books contained at least one unsupported assumption (myth) about loss and grief. In 78% of these books, authors described four or more myths and only one evidence‐based finding about coping with loss. On balance most books provided details on the myths about grief and loss with minimal discussion of the current evidence. Authors of psychiatric nursing books continue to disseminate unsupported theories about grief responses without adequately acknowledging evidence challenging core assumptions underlying them. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:486–499, 2010
Predictors of use of hearing protection among a representative sample of farmers
Authors: McCullagh M.C. , Ronis D.L. , Lusk S.L. 
Published: October 2010

AbstractFarmers experience higher rates of noise‐induced hearing loss (NIHL) than workers in most other industries. We developed a model of farmers' use of hearing protection, and tested it with a random sample (n = 532) of farmers from the upper Midwest. Barriers to using hearing protection (e.g., difficulty communicating; OR = .44, p < .003) were negatively related to use. Greater access/availability of hearing protectors (OR = 1.75, p < .010) and male gender (OR = .43, p < .019) were positively related to use. The model correctly predicted use of hearing protection for 74% of the cases. Overall, farmers demonstrated low hearing protector use, and results were similar to those from previous studies of non‐farm workers. Findings from this study will be useful in designing interventions to increase farmers' hearing protector use and decrease their rates of NIHL. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:528–538, 2010
Biobehavioral and psychological differences between overweight adults with and without waist circumference risk
Authors: Grossniklaus Daurice A. , Gary Rebecca A. , Higgins Melinda K. , Dunbar Sandra B. 
Published: October 2010

AbstractWaist circumference (WC) has emerged as an independent predictor of cardiometabolic disease. The purpose of this study was to examine differences between overweight adults with and without WC risk in four domains: demographic, clinical and biological, psychological, and behavioral. The sample (N = 87) was primarily sedentary, middle‐aged, women, and African‐Americans. The majority of participants had WC risk, those with WC risk were older, were women, and had higher body mass index, higher morning salivary cortisol levels, and more depressive symptoms than those without WC risk. Caloric and macronutrient intake did not differ between those with and without WC risk. Our findings could lead to the development of targeted interventions to prevent and/or reduce abdominal obesity, thereby reducing cardiometabolic risk. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:539–551, 2010
Does more federal environmental funding increase or decrease states' efforts?
Authors: Clark Benjamin Y. , Whitford Andrew B. 
Published: October 2010

AbstractWe examine the flow of federal grants‐in‐aid from the U.S. Environmental Protection Agency (EPA) to the states. We simultaneously model two dependent variables (the flow of EPA funds, and state environmental and natural resource budgets) to identify the independent roles of state political institutions, political preferences, economic and demographic characteristics, and the task environment. Our central focus, though, is on the relationship between grants and state spending after taking into account those direct effects. We examine the evidence for positive association (a flypaper effect) and negative association (crowding out). We show the different roles for political institutions, political preferences, demographic and economic characteristics, and the task environment in each spending context. Most importantly, we find evidence for a flypaper effect between federal funds and state spending: Federal spending and state spending are positively correlated after accounting for the contribution of the unique factors. © 2010 by the Association for Public Policy Analysis and Management.
The role of epidermal growth factor receptor in chordoma pathogenesis: a potential therapeutic target
Authors: Shalaby Asem , Presneau Nadège , Ye Hongtao , Halai Dina , Berisha Fitim , Idowu Bernadine , Leithner Andreas , Liegl Bernadette , Briggs Timothy RW , Bacsi Krisztian , Kindblom Lars‐Gunnar , Athanasou Nicholas , Amary Maria Fernanda , Hogendoorn Pancras CW , Tirabosco Roberto , Flanagan Adrienne M 
Published: October 2010

AbstractChordoma, the molecular hallmark of which is T (brachyury), is a rare malignant bone tumour with a high risk of local recurrence and a tumour from which metastatic disease is a common late event. Currently, there is no effective drug therapy for treating chordomas, although there is evidence that some patients respond to the empirical use of epidermal growth factor receptor (EGFR) antagonists. The aim of this study was to determine the role of EGFR in the pathogenesis of chordoma. Paraffin‐embedded material from 173 chordomas from 160 patients [sacro‐coccygeal (n = 94), skull‐based (n = 50), and mobile spine (n = 16)] was analysed by immunohistochemistry and revealed total EGFR expression in 69% of cases analysed. Of 147 informative chordomas analysed by FISH, 38% revealed high‐level EGFR polysomy, 4% high‐level polysomy with focal amplification, 18% low‐level polysomy, and 39% disomy. Phospho‐receptor tyrosine kinase array membranes showed EGFR activation in the chordoma cell line U‐CH1 and all of the three chordomas analysed. Direct sequencing of EGFR (exons 18–21), KRAS, NRAS, HRAS (exons 2, 3), and BRAF (exons 11, 15) using DNA from 62 chordomas failed to reveal mutations. PTEN expression was absent by immunohistochemistry in 19 of 147 (13%) analysed chordomas, only one of which revealed high‐level polysomy of EGFR. The EGFR inhibitor tyrphostin (AG 1478) markedly inhibited proliferation of the chordoma cell line U‐CH1 in vitro and diminished EGFR phosphorylation in a dose‐dependant manner, a finding supported by inhibition of phosphorylated Erk1/2. p‐Akt was suppressed to a much lesser degree in these experiments. There was no reduction of T as assessed by western blotting. These data implicate aberrant EGFR signalling in the pathogenesis of chordoma. This study provides a strategy for patient stratification for treatment with EGFR antagonists. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Polymer nanofiber‐templated fabrication and characterization of gallium oxide nanofibers consisting of granular nanoparticles
Authors: Park Soo‐Jin , Barakat Nasser AM , Jeong Kwang‐Un , Kim Hak‐Yong 
Published: October 2010

AbstractGallium oxide (β‐Ga2O3) is an interesting semiconductor that has a wide bandgap and can be used as an optoelectronic material in flat‐panel displays, solar energy conversion devices and optical limiters for UV light. However, it is difficult to fabricate and process Ga2O3 nanofibers for actual optoelectronic applications. When the excellent processability of polymeric materials is introduced into the inorganic nanofiber fabrication process, this limitation can be easily overcome. The aim of the research reported was to prepare granular Ga2O3 nanofibers utilizing an electrospun polyacrylonitrile nanofiber template combined with sol‐gel technology. Ga2O3 nanofibers were successfully fabricated by electrospinning a solution of polyacrylonitrile mixed with gallium nitrate and subsequent calcination. The surface and bulk morphologies of the calcined nanofibers investigated using field‐emission scanning electron microscopy and transmission electron microscopy (TEM) indicated that Ga2O3 nanofibers were constructed by the fusion of gallium oxide nanoparticles. TEM bright‐field images combined with selected‐area electron diffraction indicated that the average diameter of the Ga2O3 nanofibers produced was ca 55 nm and the crystalline structure was β‐Ga2O3 with a monoclinic unit cell. Furthermore, the photoluminescence spectrum of the Ga2O3 nanofibers exhibited two strong green emission peaks and one UV emission peak. Copyright © 2010 Society of Chemical Industry
Biodegradable antistatic plasticizer based on citrate electrolyte doped with alkali metal salt and its poly(vinyl chloride) composites
Authors: Wang Jiliang , Che Rongsheng , Yang Wanqing , Lei Jingxin 
Published: October 2010

AbstractAn eco‐friendly citrate electrolyte‐based antistatic plasticizer (CEAP) consisting of sodium thiocyanate‐doped tris(2‐butoxyethyl) citrate was successfully synthesized using a typical esterification reaction between citric acid and 2‐butoxyethanol. Poly(vinyl chloride) (PVC)/CEAP composites were then prepared in a Haake torque rheometer. Fourier transform infrared spectroscopy was used to confirm both the structure of the synthesized CEAP and the coordination effects between the doping salt and CEAP. The dependence of the conductivity of the synthesized CEAP on temperature and concentration of the doping salt was investigated. The surface resistivity and mechanical properties of the PVC/CEAP composites were also studied. The results showed that the surface resistivity of the PVC/CEAP composites could be effectively reduced to the order of 107Ω sq−1 when the CEAP content reached 80 phr. The surface resistivity of the composites still reached 108Ω sq−1 even at a relative humidity of 12%, showing an excellent electrostatic discharge (ESD) capacity. The fabricated composites with good ESD capacity also had a tensile strength of 10 MPa and an elongation at break of 400%, which could satisfy requirements for packaging applications or similar usages. Copyright © 2010 Society of Chemical Industry
Morphological dependency of polymer electrolyte membranes on transient salt type: effects of anion species
Authors: Esmaeili Majid , Madaeni Sayed S , Barzin Jalal 
Published: October 2010

AbstractTwo types of transition metal salts, i.e. Cu(NO3)2 and CuCl2, with different anion species were used to prepare various polyethersulfone‐based poly(N‐vinyl pyrrolidone) (PVP) composite membranes. The polymer crystallinity, strength of some of the bonds in the membrane structure and effects of anion species on the membrane morphology were investigated through X‐ray diffraction (XRD), scanning electron microscopy with energy‐dispersive X‐ray spectrometry (SEM‐EDX), Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy. The XRD results indicated an enhancement of the PVP crystallinity after addition of Cu(NO3)2. Moreover, addition of copper salt was accompanied by an increase of effective membrane distances. The FTIR analysis revealed that the nitrate ions might be better distributed than the other salt ions. The complexes created between them and carbonyl oxygens on the PVP chains were thus stronger. More powerful interactions caused a crystallinity enhancement following the addition of Cu(NO3)2. The SEM‐EDX experiment gave insight into the copper ion and carbonyl oxygen distributions in the membrane surface and active layer. The uniform distribution of copper ions resulted in a clear distribution of interchain interactions and complexes in the active layer structure and also caused structural order improvement. Copyright © 2010 Society of Chemical Industry
New thermosets obtained from bisphenol A diglycidyl ether and hydroxyl‐ended hyperbranched polymers partially blocked with benzoyl and trimethylsilyl groups
Authors: Foix David , Fernández‐Francos Xavier , Salla Josep M , Serra Àngels , Morancho Josep M , Ramis Xavier 
Published: October 2010

AbstractNew epoxy thermosets with improved flexibility were prepared by chemical modification of bisphenol A diglycidyl ether (DGEBA) with hyperbranched polymers (HBPs). Hydroxyl‐ended hyperbranched polyesters were modified by blocking part of the hydroxyl groups with trimethylsilyl or benzoyl groups. The curing of mixtures of DGEBA with various proportions of two modified HBPs using ytterbium triflate as cationic initiator was investigated using differential scanning calorimetry and thermomechanical analysis. The characterization of these materials was performed using several thermal analysis techniques and their morphology was investigated using electron microscopy. High proportions of HBPs reduced the glass transition temperature and the relaxed storage modulus but barely affected gelation. The overall curing shrinkage was controlled by the content of hydroxyl groups and by the changes of HBP molecular interactions during curing. The results indicated that the relative proportion and type of terminal groups play a role in the evolution of the curing and the properties of the thermosets. Hydroxyl groups promoted the covalent incorporation of the HBP to the network via hydroxyl‐induced chain‐transfer reactions, whereas benzoyl groups promoted phase separation. Formulations containing HBP blocked with benzoyl groups showed two phases connected through covalent linkages between the HBP‐rich phase and the epoxy matrix. Copyright © 2010 Society of Chemical Industry
Polybenzoxazine‐based composites as high‐performance materials
Authors: Kiskan Baris , Ghosh Narendra Nath , Yagci Yusuf 
Published: October 2010

AbstractPolybenzoxazines are newly developed thermoset polymers exhibiting versatility in a wide range of applications including in the electronics and aerospace industries. When combined as composites, the attractive characteristics of both components are apparent. The chemistry of benzoxazine synthesis offers wide molecular design flexibility and thus facilitates preparation of various polybenzoxazine‐based composites. This article reviews recent developments in the preparation and thermal curing of benzoxazine composites with a focus on structure–property relations of cured materials. Copyright © 2010 Society of Chemical Industry