bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reliable second‐order hexahedral elements for explicit methods in nonlinear solid dynamics
Authors: Danielson Kent T. , O'Daniel James L. 
Published: August 2010

AbstractSecond‐order hexahedral elements are common in static and implicit dynamic finite element codes for nonlinear solid mechanics. Although probably not as popular as first‐order elements, they can perform better in many circumstances, particularly for modeling curved shapes and bending without artificial hourglass control or incompatible modes. Nevertheless, second‐order brick elements are not contained in typical explicit solid dynamic programs and unsuccessful attempts to develop reliable ones have been reported. In this paper, 27‐node formulations, one for compressible and one for nearly incompressible materials, are presented and evaluated using non‐uniform row summation mass lumping in a wide range of nonlinear example problems. The performance is assessed in standard benchmark problems and in large practical applications using various hyperelastic and inelastic material models and involving very large strains/deformations, severe distortions, and contact‐impact. Comparisons are also made with several first‐order elements and other second‐order hexahedral formulations. The offered elements are the only second‐order ones that performed satisfactorily in all examples, and performed generally at least as well as mass lumped first‐order bricks. It is shown that the row summation lumping is vital for robust performance and selection of Lagrange over serendipity elements and high‐order quadrature rules are more crucial with explicit than with static/implicit methods. Whereas the reliable performance is frequently attained at significant computational expense compared with some first‐order brick types, these elements are shown to be computationally competitive in flexure and with other first‐order elements. These second‐order elements are shown to be viable for large practical applications, especially using today's parallel computers. Published in 2010 by John Wiley & Sons, Ltd.
Codf‐evolutions on polycrystalline orientation continua obtained by fast geometric estimates of plastic slip
Authors: Miehe C. , Frankenreiter I. , Rosato D. 
Published: August 2010

AbstractThis paper presents a framework for the modeling of evolving crystal orientation distribution functions (codf) and orientation averages of polycrystalline aggregates undergoing finite deformations. The method is designed for fast estimates of the polycrystalline deformation textures in metals. It bases on the Taylor approach of rigid polycrystal plasticity, where the decision of slip‐activity in the local crystalline grains is based on a geometric argument. This approach allows a purely kinematic estimate of codf evolution completely independent of the hardening response of the single crystal grains. The investigation starts with a precise description of a deforming orientation continuum. This concerns the general geometric setup as well as details of the parameterization of rotations in terms of Rodrigues vectors. We then outline Lagrangian and Eulerian geometric settings of crystal fraction conservation laws and discuss the details of their discretization. An important aspect is the definition of orientation averages. This homogenization over the orientation space is an important ingredient of a multiscale modeling of evolving anisotropy. It is shown that the discrete evaluation of orientation averages does not need the explicit computation of codf. The core of the proposed method is a fast update algorithm for rate‐independent rigid crystal plasticity that directly determines the current Rodrigues vectors. We show for several deformation modes of polycrystalline aggregates that the proposed geometric estimates predict the codf evolution and overall anisotropy very well in the range of large strains. The new method is extremely robust and suitable for multiscale methods for the description of evolving anisotropy in polycrystals. Copyright © 2010 John Wiley & Sons, Ltd.
Advanced fully coupled thermo‐mechanical plate elements for multilayered structures subjected to mechanical and thermal loading
Authors: Nali P. , Carrera E. , Calvi A. 
Published: August 2010

AbstractThis paper presents a hierarchical modeling for the analysis of multilayered structures subjected to mechanical and thermal loadings. The principle of virtual displacement is applied in the framework of the Carrera unified formulation to obtain a complete family of plate finite elements. The order of the variable description through the plate‐thickness direction can be set in the range from one to four. The results in the form of tables and graphs are given to validate the proposed elements. Pure mechanical and fully coupled thermo‐mechanical cases studies are proposed. The application of Fourier's law is not required since the plate‐thickness temperature profile is automatically obtained in the framework of the proposed approach. The numerical results are obtained through the MUL2 academic code. Copyright © 2010 John Wiley & Sons, Ltd.
Dynamics of clusters of charged particulates in electromagnetic fields
Authors: Zohdi T. I. 
Published: August 2010

AbstractThe dynamics of rigid clusters of charged particulates is the subject of this work. The work ascertains what properties of the cluster control its dynamic response to an external electromagnetic field. A primary focus is on the role of the distribution of the charges within the cluster and the effects of the Lorentz force on the overall body's linear and angular momentum. The presentation contains a derivation of the equations governing a charged cluster's dynamics and development of corresponding numerical methods for the simulation. Numerical examples are presented, along with comparisons to qualitative analytical results, where possible. Copyright © 2010 John Wiley & Sons, Ltd.
A fracture framework for Euler–Bernoulli beams based on a full discontinuous Galerkin formulation/extrinsic cohesive law combination
Authors: Becker G. , Noels L. 
Published: August 2010

AbstractA new full Discontinuous Galerkin discretization of Euler–Bernoulli beam is presented. The main interest of this framework is its ability to simulate fracture problems by inserting a cohesive zone model in the formulation. With a classical Continuous Galerkin method, the use of the cohesive zone model is difficult because inserting a cohesive element between bulk elements is not straightforward. On one hand if the cohesive element is inserted at the beginning of the simulation, there is a modification of the structure stiffness and on the other hand inserting the cohesive element during the simulation requires modification of the mesh during computation. These drawbacks are avoided with the presented formulation as the structure is discretized in a stable and consistent way with full discontinuous elements and inserting cohesive elements during the simulation becomes straightforward. A new cohesive law based on the resultant stresses (bending moment and membrane) of the thin structure discretization is also presented. This model allows propagating fracture while avoiding through‐the‐thickness integration of the cohesive law. Tests are performed to show that the proposed model releases, during the fracture process, an energy quantity equal to the fracture energy for any combination of tension‐bending loadings. Copyright © 2010 John Wiley & Sons, Ltd.
Automation of finite element formulations for large deformation contact problems
Authors: Lengiewicz Jakub , Korelc Jože , Stupkiewicz Stanisław 
Published: August 2010

AbstractThe aim of this paper is to present a general method for automation of finite element formulations of large deformation contact problems. A new automatic‐differentiation‐based notation is introduced that represents a bridge between the classical mathematical notation of contact mechanics and the actual computer implementation of contact finite elements. Automation of derivation of the required formulas (e.g. element residual and tangent matrix) combined with automatic code generation makes the finite element implementation possible at a moderate effort. Accordingly, several 3D contact formulations have been implemented in this work, including penalty and augmented Lagrangian treatments of contact constraints, and several contact smoothing techniques. A typical benchmark problem could thus be executed in an objective way leading to a comprehensive study of the efficiency and the accuracy of various formulations of 3D contact finite elements. Copyright © 2010 John Wiley & Sons, Ltd.
Harmonic enrichment functions: A unified treatment of multiple, intersecting and branched cracks in the extended finite element method
Authors: Mousavi S. E. , Grinspun E. , Sukumar N. 
Published: August 2010

AbstractA unifying procedure to numerically compute enrichment functions for elastic fracture problems with the extended finite element method is presented. Within each element that is intersected by a crack, the enrichment function for the crack is obtained via the solution of the Laplace equation with Dirichlet and vanishing Neumann boundary conditions. A single algorithm emanates for the enrichment field for multiple cracks as well as intersecting and branched cracks, without recourse to special cases, which provides flexibility over the existing approaches in which each case is treated separately. Numerical integration is rendered to be simple—there is no need for partitioning of the finite elements into conforming subdivisions for the integration of discontinuous or weakly singular kernels. Stress intensity factor computations for different crack configurations are presented to demonstrate the accuracy and versatility of the proposed technique. Copyright © 2010 John Wiley & Sons, Ltd.
Marketing a new African God: Pentecostalism and material salvation in Ghana
Authors: Bonsu Samuel K. , Belk Russell W. 
Published: August 2010

AbstractPentecostalism is an American creation that has been exported to various parts of the world. Its message of hope is produced and promoted by churches that are led by religious entrepreneurial salespeople who create value for customers through the use of marketing techniques that facilitate the blending of the local and the global; the sacred and the profane. Its success in Africa has been attributed to the African penchant for connecting every human experience to the religious. Using the marketing strategic framework of target market and four Ps as an organization tool, we draw on a year‐long ethnography in Kumasi, Ghana, to suggest that Pentecostalism in Ghana is marketed as an effective route to material success without risk to postmortem salvation. While the effective blend of the sacred and the profane allows for open public discourse, it fails to deliver on its promise of economic salvation for the poor. In fact, it causes the condition of the poor to deteriorate even further through application of its fundamental requirement: give and God will bless you according to the extent of your giving. We conclude that the new African Pentecostalism and its open embrace of contemporary consumption and materialism have arrested local religiosity and imposed an “economic imperialism” that impregnates every human experience with a commercial character.Copyright © 2010 John Wiley & Sons, Ltd.
Low‐order multi‐rate linear time‐invariant decentralized trackers using the new observer‐based sub‐optimal method for unknown sampled‐data nonlinear time‐delay system with closed‐loop decoupling
Authors: Hu N. T. , Tsai J. S. H. , Guo S. M. , Shieh L. S. , Chen Y. 
Published: August 2010

AbstractThis paper presents the low‐order multi‐rate linear time‐invariant decentralized trackers using the new observer‐based sub‐optimal method for a class of unknown sampled‐data nonlinear time‐delay system with closed‐loop decoupling. For the unknown sampled‐data nonlinear time‐delay system, we assume that the inner time delay is clearly known. Under this prerequisite, the appropriate (low‐) order decentralized linear observer for the unknown sampled‐data nonlinear system is determined by the off‐line observer/Kalman filter identification (OKID) method with artificial delay input and actual delay output. Then, the above observer has been further improved based on the proposed new observer‐based sub‐optimal approach. Sequentially, the decentralized tracker with the high gain property is proposed, so that the closed‐loop system has the decoupling property. The proposed approach constructs complete mathematics method including the concept of optimal control theory and state‐matching digital redesign technique and is quite useful for the complicated interconnected large‐scale sampled‐data nonlinear time‐delay system with unknown system equation. Copyright © 2010 John Wiley & Sons, Ltd.
Haemolytic uraemic syndrome in a patient with acute lymphoblastic leukaemia
Authors: Clarke Rachel T. , Mitchell Chris 
Published: August 2010

AbstractWe describe a patient diagnosed with haemolytic uraemic syndrome (HUS) during long‐term maintenance therapy for childhood acute lymphoblastic leukaemia (ALL). He rapidly developed renal failure, hypertension and profound thrombocytopenia. Despite suffering a large intracerebral haemorrhage, he made a full recovery without residual neurological or renal deficit. His case raises the question of whether ALL or its treatments predispose an individual to developing HUS. Pediatr Blood Cancer. 2010;55:1402–1405. © 2010 Wiley‐Liss, Inc.
Initial testing (stage 1) of the Akt inhibitor GSK690693 by the pediatric preclinical testing program
Authors: Carol Hernan , Morton Christopher L. , Gorlick Richard , Kolb E. Anders , Keir Stephen T. , Reynolds C. Patrick , Kang Min H. , Maris John M. , Billups Catherine , Smith Malcolm A. , Houghton Peter J. , Lock Richard B. 
Published: August 2010

AbstractBackgroundGSK690693 is a small molecule ATP‐competitive inhibitor of the pro‐survival kinase Akt. Since Akt regulates multiple downstream targets including transcription factors, glycogen synthase 3, the pro‐apoptotic protein Bad, as well as MDM2 and mTORC1, it was tested against the in vitro and in vivo panels of the Pediatric Preclinical Testing Program (PPTP).ProceduresGSK690693 was tested in vitro at concentrations from 1 nM to 10 µM, and against the in vivo panel of xenografts at a dose of 30 mg/kg daily × 5 for 6 consecutive weeks. Three measures of in vivo antitumor activity were used: (1) an objective response measure modeled after the clinical setting; (2) a treated to control (T/C) tumor volume measure; and (3) a time to event measure based on the median event‐free survival (EFS) of treated and control animals for each xenograft.ResultsGSK690693 inhibited cell growth in vitro with IC50 values between 6.5 nM and >10 µM. In vivo, GSK690693 significantly increased EFS in 11 of 34 (32%) solid tumor xenografts, most notably in all 6 osteosarcoma models, but not in any of the 8 ALL xenografts tested. No objective responses were observed and only one solid tumor met EFS T/C criteria for intermediate activity.ConclusionsGSK690693 demonstrated broad activity in vitro, however our results against both the solid tumor and ALL PPTP in vivo panels demonstrate that, as single agent at the dose and schedule used, GSK690693 has only modest antitumor activity. Pediatr Blood Cancer. 2010;55:1329–1337. © 2010 Wiley‐Liss, Inc.
Clinical significance of serum vascular endothelial growth factor, endostatin, and leptin levels in children with lymphoma
Authors: Okur Fatma Visal , Karadeniz Ceyda , Buyukpamukcu Munevver , Oguz Aynur , Yucel Aysegul , Cinaz Peyami , Emir Suna , Varan Ali 
Published: August 2010

AbstractBackgroundA number of clinical studies conducted in adults have demonstrated the prognostic significance of angiogenic factors in malignancies, however, only a limited number of studies have been conducted in children. The aim of this study was to determine serum vascular endothelial growth factor (VEGF), endostatin, and leptin levels in children with lymphoma and to investigate whether these factors provide prognostic information.ProcedureSerum samples from 36 children with lymphoma (non‐Hodgkin lymphoma (NHL) N = 21, Hodgkin lymphoma (HL) N = 15) were collected at diagnosis and during remission. Serum samples were also collected from 18 healthy children as the control group. Serum VEGF and endostatin levels were quantified by using enzyme‐linked immunosorbent assay (ELISA) and serum leptin by immunoradiometric assay.ResultsThe serum VEGF levels were found elevated in patients compared to controls (P = 0.033), while endostatin and leptin levels were lower in patients than in controls (endostatin, 43.9 ± 5.8 ng/ml vs. 123.6 ± 13.5 ng/ml, P < 0.001; leptin, 5 ± 1.5 ng/ml vs. 6.7 ± 1.2 ng/ml, P = 0.013). VEGF levels declined (pre, 151.6 ± 55.9 pg/ml vs. post, 16.2 ± 7.9 pg/ml, P = 0.041), while endostatin and leptin levels increased in patients who achieved remission (33 of 36 patients) when compared to pre‐treatment levels (endostatin pre, 43.1 ± 5.9 ng/ml vs. post, 65.9 ± 6.8 ng/ml, P = 0.047; leptin, pre, 5.3 ± 1.6 ng/ml vs. post, 9.8 ± 2.7 ng/ml, P = 0.012). Serum VEGF, endostatin, and leptin levels were not predictive of survival.ConclusionSerial measurement of serum VEGF, endostatin, and leptin levels could potentially be used to predict response to treatment or progressive disease in children with lymphoma. Pediatr Blood Cancer. 2010;55:1272–1277. © 2010 Wiley‐Liss, Inc.
Oncolytic virotherapy reaches adolescence
Authors: Hammill Adrienne M. , Conner Joseph , Cripe Timothy P. 
Published: August 2010

AbstractLytic viruses kill cells as a consequence of their normal replication life cycle. The idea of harnessing viruses to kill cancer cells arose over a century ago, before viruses were even discovered, from medical case reports of infections associated with cancer remissions. Since then, there has been no shortage of hype, hope, or fear regarding the prospect of oncolytic virotherapy for cancer. Early developments in the field included encouraging antitumor efficacy both in animal studies in the 1920s–1940s and in human clinical trials in the 1950s–1970s. Despite its long‐standing history, oncolytic virotherapy was an idea ahead of its time. Without needed advances in molecular biology, virology, immunology, and clinical research ethics, early clinical trials resulted in infectious complications and were fraught with controversial research conduct, so that enthusiasm in the medical community waned. Oncolytic virotherapy is now experiencing a major growth spurt, having sustained numerous laboratory advances and undergone multiple encouraging adult clinical trials, and is now witnessing the emergence of pediatric trials. Here we review the history and salient biology of the field, including preclinical and clinical data, with a special emphasis on those agents now being tested in pediatric cancer patients. Pediatr Blood Cancer. 2010;55:1253–1263. © 2010 Wiley‐Liss, Inc.
Management of sialoblastoma with surgery and brachytherapy
Authors: Shan Xiao‐Feng , Cai Zhi‐Gang , Zhang Jian‐Guo , Zhang Jie , Gao Yan , Yu Guang‐Yan 
Published: August 2010

AbstractSialoblastoma is a rare congenital or perinatal salivary gland tumor with significant variability in histological appearance and biological behavior. We reported one case of sialoblastoma occurring in the parotid gland of an 18‐month‐old female. The tumor was excised with negative margins, and the sacrificed facial nerve was reconstructed with great auricular nerve graft. The tumor recurred 6 months after operation and was treated with 125I seed implant brachytherapy. No recurrence was found after 21 months of follow‐up. Pediatr Blood Cancer. 2010;55:1427–1430. © 2010 Wiley‐Liss, Inc.
Opposing effects of nanoclay on viscoelastic response of reactive phenoxy/poly (trimethylene terephthalate) blends: Clay‐induced transreactions versus percolated network formation
Authors: Seyfi Javad , Jafari Seyed‐Hassan , Khonakdar Hossein Ali 
Published: August 2010

AbstractThe role of nanofillers in reactive blends, which are compatibilized via interchange/exchange reactions, in particular transesterification reactions, is still a challenge. In this study, effects of clay on viscoelastic response of reactive melt intercalated phenoxy/poly (trimethylene terephthalate) blends are investigated. Using rheological plots, it was found that at low clay contents, clay‐induced transreactions could cause an unexpectedly enhanced viscous response. But higher clay contents lead to an enhancement in elastic behavior by inducing the formation of a percolated network. The observed opposing effects of clay particles on viscoelastic response were further examined by stress relaxation analysis, which verified the enhanced viscous response at low clay contents. The effect of interaction between the silicate layers and the blend matrix is also probed by using two different organo‐modifiers. Viscoelastic behavior of samples was also studied by dynamic mechanical analysis, and the results corroborated our findings from rheological measurements. Based on loss modulus data, the improved dynamic homogeneity of nanocomposites is attributed to the enhanced transreactions and stronger hydrogen bonds between the blend components. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Surface‐modified sisal fiber‐reinforced eco‐friendly composites: Mechanical, thermal, and diffusion studies
Authors: P.A. Sreekumar , Joseph Kuruvilla , G. Unnikrishnan , Thomas Sabu 
Published: August 2010

AbstractTo improve the fiber/matrix interaction, sisal fibers were subjected to various chemical and physical modifications such as mercerization, heating at 100°C, permanganate treatment, benzoylation, and silanization. Polyester composites were fabricated using compression molding. Tensile and flexural properties increased for every treated fiber‐reinforced composites with a reduction in the impact strength. This is attributed to the improved interfacial adhesion between fiber and polyester matrix. An increase in thermal stability was observed for the treated fiber‐reinforced composites especially at lower temperature. Significant reduction in water uptake occurred for the treated fiber‐reinforced composites at 30°C and 90°C. Scanning electron micrograph studies have been used to substantiate the above observations. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
In‐plane thermal conductivity modeling of carbon‐filled liquid crystal polymer–based resins
Authors: Adams Tayloria N.G. , Olson Tamara R. , King Julia A. , Keith Jason M. 
Published: August 2010

AbstractAdding conductive carbon fillers to insulating thermoplastic resins increases composite electrical and thermal conductivity. In this study, varying amounts of three different carbons (carbon black, synthetic graphite particles, and carbon fiber) were added to Vectra A950RX liquid crystal polymer. The in‐plane thermal conductivity of the resulting single filler composites was tested. The results showed that adding synthetic graphite particles caused the largest increase in the in‐plane thermal conductivity of the composite. The composites were modeled using ellipsoidal inclusion problems to predict the effective in‐plane thermal conductivities at varying volume fractions with only physical property data of the constituents. The synthetic graphite and carbon black were modeled using the average field approximation with ellipsoidal inclusions and the model showed good agreement with the experimental data. The carbon fiber polymer composite was modeled using an assemblage of coated ellipsoids and the model showed good agreement with the experimental data. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers