bluuebunny/crossref_metadata_2025_split huggingface dataset:
An efficient finite–discrete element method for quasi‐static nonlinear soil–structure interaction problems
Authors: Dang Hoang K. , Meguid Mohamed A. 
Published: September 2011

SUMMARYAn efficient finite–discrete element method applicable for the analysis of quasi‐static nonlinear soil–structure interaction problems involving large deformations in three‐dimensional space was presented in this paper. The present method differs from previous approaches in that the use of very fine mesh and small time steps was not needed to stabilize the calculation. The domain involving the large displacement was modeled using discrete elements, whereas the rest of the domain was modeled using finite elements. Forces acting on the discrete and finite elements were related by introducing interface elements at the boundary of the two domains. To improve the stability of the developed method, we used explicit time integration with different damping schemes applied to each domain to relax the system and to reach stability condition. With appropriate damping schemes, a relatively coarse finite element mesh can be used, resulting in significant savings in the computation time. The proposed algorithm was validated using three different benchmark problems, and the numerical results were compared with existing analytical and numerical solutions. The algorithm performance in solving practical soil–structure interaction problems was also investigated by simulating a large‐scale soft ground tunneling problem involving soil loss near an existing lining. Copyright © 2011 John Wiley & Sons, Ltd.
Column generation algorithm for sensor coverage scheduling under bandwidth constraints
Authors: Rossi André , Singh Alok , Sevaux Marc 
Published: September 2011

AbstractThis article addresses three problems that arise in coverage scheduling for wireless sensor networks subject to bandwidth constraints. The first problem focuses on minimizing the total breach under a lifetime constraint, where a breach occurs when some targets are not covered by active sensors. The second problem aims at maximizing the network lifetime under a breach constraint. Finally, the problem of computing the possible trade‐offs between breach and lifetime offered by the sensor network is also addressed. An exact approach based on a column generation algorithm is proposed for solving these problems, and a heuristic is also derived from it and briefly presented. The use of a genetic algorithm within the column generation scheme appears to significantly decrease computation time. © 2011 Wiley Periodicals, Inc. NETWORKS, 2012
THE INFLUENCE OF E‐GOVERNMENT ON ADMINISTRATIVE DISCRETION: THE CASE OF LOCAL GOVERNMENTS IN EGYPT
Authors: Reddick Christopher G. , Abdelsalam Hisham M. , Elkadi Hatem 
Published: September 2011

SUMMARYOne important but often understudied area of research in public administration is the effect of e‐government on administrative discretion. This article examines e‐government factors that influence administrative discretion through a survey of local governments. The focus of this study is on Egyptian local governments, which are using e‐government to modernise public service delivery. Through a survey of administrative officials in these governments, this study found evidence that e‐government factors of collaboration and organisational change influenced administrative discretion. Other common factors noted in the literature such as size of the local government and demand by citizens for e‐government did not register an effect on administrative discretion. The results of this study imply that local governments should do more to enhance e‐government to reduce administrative discretion, especially in the area of increasing collaboration. Copyright © 2011 John Wiley & Sons, Ltd.
Primary cilia and coordination of receptor tyrosine kinase (RTK) signalling
Authors: Christensen Søren T , Clement Christian A , Satir Peter , Pedersen Lotte B 
Published: September 2011

AbstractPrimary cilia are microtubule‐based sensory organelles that coordinate signalling pathways in cell‐cycle control, migration, differentiation and other cellular processes critical during development and for tissue homeostasis. Accordingly, defects in assembly or function of primary cilia lead to a plethora of developmental disorders and pathological conditions now known as ciliopathies. In this review, we summarize the current status of the role of primary cilia in coordinating receptor tyrosine kinase (RTK) signalling pathways. Further, we present potential mechanisms of signalling crosstalk and networking in the primary cilium and discuss how defects in ciliary RTK signalling are linked to human diseases and disorders. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Enhanced Sample Preparation for Quantitation of Microcystins by Matrix‐Assisted Laser Desorption/Ionisation–Time of Flight Mass Spectrometry
Authors: Puddick Jonathan , Prinsep Michèle R. , Wood Susanna A. , Craig Cary S. , Hamilton David P. 
Published: September 2011

ABSTRACTIntroductionMicrocystins (MCs) are a group of cyanotoxins which pose a serious health threat when present in aquatic systems. Quantitative analysis of MCs by matrix‐assisted laser desorption/ionisation–time of flight (MALDI–TOF) mass spectrometry has potential for the processing of large numbers of samples quickly and economically. The existing method uses an expensive internal standard and protocols that are incompatible with automated sample preparation and data acquisition.ObjectiveTo produce a MALDI–TOF sample preparation technique for the quantitation of MCs that not only maintains reproducibility and sensitivity, but is also compatible with an automated work‐flow.MethodologySeven different MALDI–TOF sample preparations were assessed for signal reproducibility (coefficient of variation) and sensitivity (method detection limit) using a cost‐effective internal standard (angiotensin I). The best preparation was then assessed for its quantitative performance using three different MC congeners ([Dha7] MC‐LR, MC‐RR and MC‐YR).ResultsThe sensitivity of six of the preparations was acceptable, as was the reproducibility for two thin‐layer preparations performed on a polished steel target. Both thin‐layer preparations could be used with a MALDI‐TOF mass spectrometer that automatically acquires data, and one could be used in an automated sample preparation work‐flow. Further investigation using the thin‐layer spot preparation demonstrated that linear quantification of three different MC congeners was possible.ConclusionThe study demonstrates that with different sample preparation methods and modern instrumentation, large numbers of samples can be analysed rapidly for MCs at low cost. Copyright © 2011 John Wiley & Sons, Ltd.
Orientation, mechanical, and optical properties of poly (lactic acid) nanoclay composite films
Authors: Tabatabaei Seyed H. , Ajji Abdellah 
Published: September 2011

AbstractIn this study, the orientation, mechanical as well as the optical properties of multilayer films of nanoclay filled poly (lactic acid) (PLA) as the core layer and polyethylene (PE) as the skin layer obtained from the film blowing process were investigated. The effect of nanoclay content in the range of 1–7.5 wt% was considered. The orientation of the polymers crystal unit cells, alignment of clay platelets as well as the extent of intercalation and exfoliation were studied using wide angle X‐ray diffraction (WAXD). The measurement of d‐spacing of the 001 plane (normal to platelets plane) of the clay tactoids indicated intercalation of the silicate layers in the PLA nanocomposite multilayer films. The Young modulus and tear resistance along the machine and transverse directions (MD and TD, respectively) improved significantly with the presence of the nanoparticles and percentage of nanofiller studied. The haze of the nanocomposite films decreased with clay concentration up to 5 wt% and increased by further addition of the nanoclay. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Properties of PET/clay nanocomposite films
Authors: Ghasemi Hesam , Carreau Pierre J. , Kamal Musa R. , Tabatabaei Seyed H. 
Published: September 2011

AbstractPolyethylene terephthalate (PET) nanocomposite films were prepared by cast extrusion followed by uniaxial stretching, using chill rolls. Transmission electron microscopy (TEM) and wide angle X‐ray diffraction (WAXD) showed that the clay layers were aligned in the machine direction (MD) in the PET/clay nanocomposite (PCN) films. Differential scanning calorimetry (DSC) showed that PCN films have higher crystallinity than the neat PET films, possibly due to the nucleating role of the silicate layers. The PCN films became hazier as the clay content increased, but the film transparency remained in the acceptable range. Oxygen permeability of the PCN films decreased by 23% compared to the neat PET film. This is comparable with predictions of models proposed in the literature. Silicate incorporation brought about 20% increase in the tensile modulus, while the puncture and tear propagation resistance were reduced, due to brittleness of the PCN films. The measured modulus (1.7 GPa) was somewhat smaller than the values predicted using the Pseudoinclusion model (2.1 GPa). POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
The competencies initiative in American professional psychology: Implications for school psychology preparation
Authors: Daly Edward J. , Doll Beth , Schulte Ann C. , Fenning Pamela 
Published: September 2011

AbstractIn the past decade, American professional psychology has taken significant steps toward a unified statement of the competencies that define the practice of psychology, regardless of specialty. The purpose of this article is to explain the current competency initiative in professional psychology and examine its implications and potential impact on graduate training in school psychology. A brief overview of competency‐based training and the current competencies initiative in psychology is presented. Two significant challenges to implement competency‐based training are then discussed. The first challenge has to do with conceptualizations of training and practice across accreditation agencies. As a part of the discussion, two recently published competency documents from the Assessment of Competencies Benchmark Workgroup of the American Psychological Association and the National Association of School Psychologists are compared in a content analysis. The second challenge discussed is the difficulties associated with operationalizing and measuring competencies. Specifically, the empirical and consequential bases for existing assessment methods are examined. In spite of current pressure by accrediting agencies to implement a competency‐based training model, based on the challenges examined in this article, significant work remains if school psychology trainers want to assure that competency‐based training is done well. © 2011 Wiley Periodicals, Inc.
Polyhedral oligomeric silsesquioxane‐based fluoroether‐containing terpolymers: Synthesis, characterization and their water and oil repellency evaluation for cotton fabric
Authors: Gao Yu , He Chuanglong , Qing Feng‐Ling 
Published: September 2011

AbstractA series of polyhedral oligomeric silsesquioxane (POSS) based hybrid copolymers poly(POSS‐co‐methyl methacrylate −co‐ 4‐vinylbenzyl fluoroether carboxylate) (P(POSS‐MMA‐VBFC)) were prepared via radical polymerization and characterized by nuclear magnetic resonance, fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, X‐ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The thermal properties of these polymers (Td > 250 °C) were improved by the introduction of POSS cage. The cotton fabrics coated with the polymers possessed excellent water and oil repellency. The water and salad oil contact angle could be achieved from 133° to 159° and from 127° to 141° respectively as the content of POSS in the polymer increased from 0 to 7.1 wt %. Moreover, the cotton fabric coated with the terpolymer was less flammable than the uncoated one. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Branched cationic polyurethane prepared by polyaddition of chloromethylated five‐membered cyclic carbonate and diethylenetriamine in molten salts
Authors: Ochiai Bungo , Koda Kazuhiro , Endo Takeshi 
Published: September 2011

AbstractA branched cationic polymer was synthesized by polyaddition of 4‐chloromethyl‐1,3‐dioxolan‐2‐one and diethylenetriamine in molten salts. The polyaddition proceeded through nucleophilic addition of the primary amino group to the cyclic carbonate structure and quarternization of the secondary amino group with the chloromethyl group. The resulting cationic polymer was a good and recyclable catalyst for the reaction of carbon dioxide and epoxides owing to the ammonium structure. The complexation with DNA was confirmed by dynamic light scattering and zeta potential measurements, and it suggests the potential application as a carrier for drug delivery system. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
(Salan)CrCl, an effective catalyst for the copolymerization and terpolymerization of epoxides and carbon dioxide
Authors: Darensbourg Donald J. , Poland Ross R. , Strickland Amanda L. 
Published: September 2011

AbstractThe selective transformation of CO2 and epoxides to afford completely alternating copolymers remains a topic of much interest for the potential utilization of carbon dioxide in chemical synthesis. The use of salicylaldimine (salen)‐metal complexes and their saturated (salan)‐metal versions have proven to be the most effective and robust single‐site catalyst for these processes. Herein, we report on mechanistic aspects of the copolymerization of alicyclic and aliphatic epoxides with CO2 in toluene solution and in neat epoxides in the presence of a (salan)CrCl/onium salt catalyst system. The activation barriers for both cyclohexene oxide(CHO)/CO2 and propylene oxide(PO)/CO2 were shown to be significantly higher in toluene solution than those previously reported for reactions carried out under solventless conditions. Terpolymerization of CHO/vinylcyclohexene oxide/CO2 was shown via Fineman‐Ross analysis at 60 °C to proceed with little monomer selectivity, for example, rCHO = 1.03 and rVCHO = 0.847. On the other hand, terpolymerization of CHO/PO/CO2 occurred at 25 °C with a propensity for incorporation of PO in the polymer. However, at 40 °C, Fineman‐Ross analysis revealed rCHO and rPO values of 0.869 and 1.49, thereby affording a terpolymer with a more equal distribution of monomers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Structural characterization by nuclear magnetic resonance of the impact of phosphorylation in the proline‐rich region of the disordered Tau protein
Authors: Sibille Nathalie , Huvent Isabelle , Fauquant Caroline , Verdegem Dries , Amniai Laziza , Leroy Arnaud , Wieruszeski Jean‐Michel , Lippens Guy , Landrieu Isabelle 
Published: September 2011

AbstractPhosphorylation of the neuronal Tau protein is implicated in both the regulation of its physiological function of microtubule stabilization and its pathological propensity to aggregate into the fibers that characterize Alzheimer's diseased neurons. However, how specific phosphorylation events influence both aspects of Tau biology remains largely unknown. In this study, we address the structural impact of phosphorylation of the Tau protein by Nuclear Magnetic Resonance (NMR) spectroscopy on a functional fragment of Tau (Tau[Ser208–Ser324] = TauF4). TauF4 was phosphorylated by the proline‐directed CDK2/CycA3 kinase on Thr231 (generating the AT180 epitope), Ser235, and equally on Thr212 and Thr217 in the Proline‐rich region (Tau[Ser208‐Gln244] or PRR). These modifications strongly decrease the capacity of TauF4 to polymerize tubulin into microtubules. While all the NMR parameters are consistent with a globally disordered Tau protein fragment, local clusters of structuration can be defined. The most salient result of our NMR analysis is that phosphorylation in the PRR stabilizes a short α‐helix that runs from pSer235 till the very beginning of the microtubule‐binding region (Tau[Thr245‐Ser324] or MTBR of TauF4). Phosphorylation of Thr231/Ser235 creates a N‐cap with helix stabilizing role while phosphorylation of Thr212/Thr217 does not induce modification of the local transient secondary structure, showing that the stabilizing effect is sequence specific. Using paramagnetic relaxation experiments, we additionally show a transient interaction between the PRR and the MTBR, observed in both TauF4 and phospho‐TauF4. Proteins 2012. © 2011 Wiley Periodicals, Inc.
Nanochemical reactions by laser annealing of ferrocene filled single‐walled carbon nanotubes
Authors: Briones Antonio , Liu Xianjie , Kramberger Christian , Saito Takeshi , Pichler Thomas 
Published: September 2011

AbstractThermal annealing of FeCp2 filled SWCNT yields DWCNT via a catalytic reaction. The annealing time and temperature allow controlling the doping level. We present an in situ experimental approach to study the dynamics of the transformation of FeCp2 filled SWCNT to doped DWCNT. A frequency doubled Nd/YAG laser was used to anneal the samples and a He–Ne laser and a tunable Argon–Krypton laser were used to measure the Raman spectrum with different wavelengths. Samples were annealed in high vacuum, and Raman spectra of the transition to DWCNT were monitored. The observed inner tube mean diameters at 633 nm are 1.00, 0.71, and 0.51 nm for ferrocene filled eDIPS, laser ablation and HiPco SWCNT, respectively.magnified image
Raman spectra of a FeCp2@SWCNT and a DWCNT.
Security enhancement of the communication‐efficient AUTHMAC_DH protocols
Authors: Lv Chao , Ma Maode , Li Hui , Ma Jianfeng , Niu Ben 
Published: September 2011

ABSTRACTAuthentication and key distribution (AKD) protocols have become more important in the design of communication systems. The design criteria of the AKD protocols include the scalability, the communication efficiency, the computational efficiency, and the robustness of security. In this paper, we first analyze the vulnerability of an AKD protocol under the off‐line guessing attack. Then, we propose an enhanced AKD protocol to overcome the vulnerability. Security analysis and formal verification by using AVISPA toolkit show that the proposed protocol can keep all the previous properties and is secure against the off‐line guessing attack. Copyright © 2011 John Wiley & Sons, Ltd.
The perils of high‐growth markets
Authors: Aaker David A. , Day George S. 
Published: September 2011

AbstractThe conventional wisdom that businesses should invest in growth markets is based upon the assumptions that, in the early phase of a growth market, share gains are easier and worth more, the experience curve will lead to advantage, price pressure will be low, needed access to the technology will result and future entries will be deterred. These assumptions are examined and six major types of growth market risks are discussed. Finally, conditions which should be present if an early entry into a growth market is attempted are identified.
The economic dynamics of work
Authors: Haley Michael 
Published: September 2011

AbstractOnly by developing management systems based on appropriate standards can a business successfully learn how to improve the technology of work. As a result, a new economics of work is created where the evolution of large organizations makes economic sense. But economies of scale no longer require rigid mass production of a limited product line. Flexibility can be introduced to produce product diversity without losing the efficiencies of standardization. Thus manufacturing can operate more flexibly like a service by learning to apply industrial robots and other smart machines. Service businesses can also learn how to manage more systematically by designing standard menus of operations.
Using simulated mergers to evaluate corporate diversification strategies
Authors: Silhan Peter A. , Thomas Howard 
Published: September 2011

AbstractThis study suggests that simulated mergers can be used to help evaluate the effects of diversification on corporate performance. The results, which are consistent with a risk‐reduction motive for conglomerate diversification, imply that conglomerate strategies focused on fewer and larger units may be advantageous in terms of certain measures of risk and return. Forecast error is used here to measure strategic risk, and return on equity is used to measure return.
Matching vertical integration strategies to competitive conditions
Authors: Harrigan Kathryn Rudie 
Published: September 2011

AbstractThis paper contrasts the vertical integration strategies of 192 firms in the presence of diverse environmental and strategic forces to suggest how successful uses of vertical integration differ from less successful ones. Briefly, firms which did not use vertical integration as effectively transferred more goods and services internally, and they did so more often under adverse industry conditions. A frequent error was to undertake more integrated activities in‐house and engage in longer chains of processing from ultra‐raw materials to finished goods. Ironically, many of the vertically integrated firms that suffered adversity possessed the bargaining power needed to contract advantageously for goods or services, but accepted an overly risky ownership position unnecessarily by producing them, instead.
The path dependence of organizational reputation: how social judgment influences assessments of capability and character
Authors: Mishina Yuri , Block Emily S. , Mannor Michael J. 
Published: September 2011

AbstractDrawing upon theory on social judgments and impression formation from social psychology, this paper explores the socio‐cognitive processes that shape the formation of favorable and unfavorable organizational reputations. Specifically, we suggest that stakeholders make distinctions between an organization's capabilities and its character. We explain the nature and function of each and articulate the manner in which judgment heuristics and biases manifest in the development of capability and character reputations. In doing so, this research explores both the positive and negative sides of organizational reputation by examining the manner in which different types of reputations are built or damaged, and how these processes influence the ability of managers to enhance and protect these reputations. Copyright © 2011 John Wiley & Sons, Ltd.
Wrinkled Liquid‐Crystalline Microparticle‐Enhanced Photoresponse of PDLC‐Like Films by Coupling with Mechanical Stretching
Authors: Yu Haifeng , Dong Chong , Zhou WeiMin , Kobayashi Takaomi , Yang Huai 
Published: September 2011

AbstractPhotoresponsive behaviors are studied in hybrid liquid‐crystalline (LC) films prepared with light‐responsive LC polymer microparticles as dopants using photoinert polymers as a host material. Upon mechanical stretching, both topological shape change and mesogenic alignment occur in the LC polymer microparticles, enabling the polymer‐dispersed LC (PDLC)‐like films to bend toward a light source upon UV irradiation. The rough morphologies of the hydrophobic LC microparticles enhance their interactions with hydrophilic polymer substrates. The bilayer‐like structures of the hybrid film formed in the fabrication processes are responsible for the photomechanical behavior, which is reversibly controlled by combing light irradiation with the stretching processes.