bluuebunny/crossref_metadata_2025_split huggingface dataset:
Full‐scale dynamic testing and analysis of a reservoir intake tower
Authors: Daniell W. E. , Taylor C. A. 
Published: April 2007

AbstractDynamic tests were conducted on a 50 m high intake tower at Wimbleball dam in the U.K. The results were compared against predictions from a corresponding numerical model. The aim of this work was to validate the assumption that the compressibility of the reservoir water is not a significant factor in the seismic analysis of intake towers.Three sets of tests were conducted on different occasions with different water levels in the reservoir. In the first two tests, modal characteristics of the tower were determined from the measured responses under ambient, hammer and human excitation. These results were used in planning the final set of tests where rotating eccentric mass exciters were used to vibrate the tower. Structural accelerations and hydrodynamic pressures were measured over the height of the tower for three important bending modes of vibration.The finite element method was used to develop a numerical model for Wimbleball tower. The tower was discretized with traditional solid elements and the reservoir with incompressible fluid elements. This model was analysed to predict the modal characteristics and harmonic responses of the tower and reservoir under the various conditions imposed during the dynamic tests.Theoretical predictions of the tower's accelerations and hydrodynamic pressures in the reservoir were compared against the test results. Excellent agreement was found for the natural frequencies and mode shapes while predictions of the harmonic responses were only fair.The observed responses of the tower and reservoir support the assumption that reservoir compressibility is not a significant factor in the seismic analysis of towers of this size.
Evaluation of an active variable‐damping structure
Authors: Polak E. , Meeker G. , Yamada K. , Kurata N. 
Published: April 2007

AbstractWe present a numerical evaluation of the potential improvements in seismic disturbance rejection to be obtained by using active variable damping control in a structure. Using the responses to seismic excitation of an optimally controlled variable structure and of a minimax‐optimal designed fixed structure, we obtain an upper bound on the achievable performance and a lower bound on the acceptable performance of a control system for a variable‐damping structure. Both of these bounds are relative to an energy‐function criterion. Our numerical experiments lead to the following conclusions:
The gap between the upper and lower bounds is rather small, which makes designing a feedback law, that results in performance superior to that of a minimax‐optimal designed structure, very difficult. The best choice for a feedback law appears to be continuous moving horizon control, whose implementation requires ground motion prediction up to 0.2 sec ahead, possibly using sensors located a small distance away from the site.
A minimax‐optimal designed structure gives very good seismic disturbance suppression, not only for the earthquakes used in its design, but also for other earthquakes of similar intensity. Controlled variable structures are likely to offer advantages when earthquakes are moderate to severe, particularly at sites, such as landfills and dry lake beds, where resonances can be expected, but the resonance frequency cannot be estimated in advance.
An experimental study on active control of in‐plane cable vibration by axial support motion
Authors: Fujino Yozo , Susumpow Thumanoon 
Published: April 2007

AbstractActive control of slightly sagged cables using the axial motion at the cable support is studied experimentally and analytically. Non‐linear modal equations of a cable are presented, and two control schemes are identified, i.e. active stiffness control and active sag‐induced force control. In this study, emphasis is placed on the active sag‐induced force control. Additional damping is analytically expressed when a velocity feedback control is used. Although the active sag‐induced force control can be applicable only for in‐plane symmetric modes, it is shown that it is very efficient for the first mode. An experiment is conducted using a scaled cable model of 2 m length. First, it is shown by the experiment that the analytical model can predict well the non‐linear cable motion. Next, sag‐induced force control is examined using free vibration and harmonic excitations. The results agree well with the analytical predictions and confirm that additional damping can be obtained efficiently from the axial support motion.
Energy dissipation behaviour of shear panels made of low yield steel
Authors: Nakashima Masayoshi , Iwai Satoshi , Iwata Mamoru , Takeuchi Toru , Konomi Shinzo , Akazawa Takashi , Saburi Kazuhiro 
Published: April 2007

AbstractThis paper presents the results of a pilot test conducted for evaluating the energy dissipation behaviour of shear panels made of low yield steel whose 0.2 per cent offset yield stress is 120 MPa. A total of six full‐scale shear panels were tested with the loading condition, stiffener spacing, and magnitude of axial force as test variables. The shear panels tested yielded at a shear force that is approximately 1/3 of the yield shear force of equivalent shear panels made of common mild steel. Shear panels with proper stiffener arrangement exhibited stable hysteresis, thus ensuring large energy dissipation capacity. Sufficient strain hardening was observed in the shear panels tested, with their energy dissipation capacity about 1.5 times larger than that of an equivalent linear‐elastic and perfect‐plastic system. Plate buckling did not lead the shear panels to immediate degradation in their energy dissipation capacity. Post‐buckling resistance was found to be a subject that requires further studies for quantifying the performance of shear panels made of low yield stress steel as hysteretic dampers.
Dynamic modelling and design of earthquake‐resistant walls
Authors: Linde Peter , Bachmann Hugo 
Published: April 2007

AbstractIn multi‐storey structures reinforced concrete structural walls may provide significant resistance against earthquake action. For a check of the global dynamic performance of such walls, there is a need for efficient numerical models. This paper presents a newly developed model used for the simulation of the dynamic behaviour of earthquake‐resistant multistorey walls. The model, which is based on an earlier proposal by Kabeyasawa et al. consists of non‐linear springs connected by rigid beams. The model properties are derived based on elastic theory for cantilever walls as well as nonlinear physical behaviour of wall cross‐sections supplemented by empirical data. The model behaviour is checked against experimental results and then the model is applied in an example comprising a non‐linear time history analysis of an eight‐storey wall structure. Based on the findings from the numerical model, improved capacity design rules for walls are proposed.
Observations on non‐linear dynamic characteristics of suspension bridges
Authors: Brownjohn J. M. W. 
Published: April 2007

AbstractFor most forms of loading static and dynamic response of a suspension bridge is modelled adequately by linear analysis. By examining the two principal non‐linearities of inclined and vertical hanger suspension bridges the limitations of linear analyses are shown. The inclined hanger configuration is shown to be the more strongly non‐linear. Some examples are given for simplified planar analyses of this type of bridge to large amplitude vehicular, random, sinusoidal and propagating earthquake excitation, showing that the effect only becomes significant when deflections approach the extent of cable sag due to cable elasticity.
Influence of the spatial distribution of energy‐dissipating bracing elements on the seismic response of multistorey frames
Authors: Ruiz Sonia E. , Urrego Olga E. , Silva Francisco L. 
Published: April 2007

AbstractSeveral reinforced concrete frames with different dissipator distributions, and a conventional moment‐resisting frame, are compared in order to select the best dissipator distribution from the point of view of seismic response and structural design. The structures with dissipators are designed according to a criterion proposed in the present paper. Each frame is excited with a set of eleven simulated accelerograms. The choice of the best dissipation distribution is based mainly on the differences between the mean of the maximum overturning moments developed at the base of the frames and between the weights of steel reinforcement and concrete resulting from the structural design of each frame. A comparison of initial construction costs of a building with dissipators and a conventional building shows that the former is 3·5 per cent more expensive.
Critical earthquake input power spectral density function models for engineering structures
Authors: Manohar C. S. , Sarkar Abhijit 
Published: April 2007

AbstractThe problem of determining optimal power spectral density models for earthquake excitation which satisfy constraints on total average power, zero crossing rate and which produce the highest response variance in a given linear system is considered. The solution to this problem is obtained using linear programming methods. The resulting solutions are shown to display a highly deterministic structure and, therefore, fail to capture the stochastic nature of the input. A modification to the definition of critical excitation is proposed which takes into account the entropy rate as a measure of uncertainty in the earthquake loads. The resulting problem is solved using calculus of variations and also within linear programming framework. Illustrative examples on specifying seismic inputs for a nuclear power plant and a tall earth dam are considered and the resulting solutions are shown to be realistic.
Willingness‐to‐pay for a statistical life in the times of a pandemic
Authors: Gyrd‐Hansen Dorte , Halvorsen Peder Andreas , Kristiansen Ivar Sønbø 
Published: April 2007

AbstractA contingent valuation was performed based on cross‐sectional web‐based interviews of individuals aged 16–82 years of age presenting a scenario of influenza pandemic. The mean WTP for a course of Tamiflu was NOK 1034 (median NOK 250). Anxious individuals perceived the pandemic mortality risk to be higher than others, but also perceived the benefit of Tamiflu as greater. They also expressed a higher WTP for Tamiflu, but the implied VOSL was less than for other respondents. The results suggest that fear and anxiety distort decision making under uncertainty and decrease focus on the perceived risk reduction. Copyright © 2007 John Wiley & Sons, Ltd.
Information systems support for CNC machinists: Evaluating the impact of information technology at the shop floor
Authors: Butcher Tim , Greenough Richard M. 
Published: April 2007

AbstractAs information technology (IT) capabilities increase, manufacturing businesses are realigning their information systems infrastructure to remain competitive. This has resulted in substantial increases in IT use in technical areas of the business. Nevertheless, conventional paper‐based information systems are still common at the shop floor. Hence, manufacturers need to understand whether there is benefit in extending IT functionality to the shop floor. By evaluating the impact of hypermedia information systems on the independent decision‐making and communication capabilities of computer numerical control (CNC) machinists, this research aims to identify the shop floor benefits of replacing existing paper‐based systems with this relatively new technology in this context. The research findings have wide‐ranging implications for further research into the strategic implementation of shop floor IT and for future work structures in the metal cutting industry. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 299–314, 2007.
Human error driving the development of a checklist for foreign material exclusion in the nuclear industry
Authors: Kenger Patrik , Karlsson Anders 
Published: April 2007

AbstractIn this article we describe an approach to develop a checklist for foreign material exclusion. Foreign material is material that should not be part of, or supplied with, the product because it can affect the performance of, for example, nuclear fuel rods of nuclear plants. The research itself was initiated by the presence of different types of human errors. Specifically in the nuclear industry, where there is zero tolerance for errors, work to continuously improve safety and quality is of major importance. Our approach should support such work. As a theoretical base, we have considered team errors as well as individual errors. The suggested practical approach is based on foreign materials that originate in or are introduced into a product or a process. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 283–298, 2007.
Antiresorptive agents and osteoclast apoptosis
Authors: Stern Paula H. 
Published: April 2007

AbstractAntiresorptive agents have proven to be effective therapies for the treatment of bone diseases associated with excessive osteoclast activity. Decreased osteoclast formation, inhibition of osteoclast actions, and reduced osteoclast survival represent mechanisms by which antiresorptive agents could act. The goals of this article are to present the evidence that antiresorptive agents can decrease osteoclast survival through apoptosis, to review the mechanisms by which they are thought to activate the apoptotic process, and to consider whether the actions on apoptosis fully account for the antiresorptive effects. As background, the apoptotic process will be briefly summarized together with the evidence that factors that promote osteoclast survival affect steps in the process. Following this, therapeutic agents that are both antiresorptive and can stimulate osteoclast apoptosis will be discussed. Other bone therapeutic agents that are either antiresorptive or apoptotic, but not both, will be described. Finally, newer antiresorptive compounds that elicit apoptosis and could represent potential therapeutic agents will be noted. J. Cell. Biochem. 101:1087–1096, 2007. © 2007 Wiley‐Liss, Inc.
Can a physics‐based, all‐atom potential find a protein's native structure among misfolded structures? I. Large scale AMBER benchmarking
Authors: Wroblewska Liliana , Skolnick Jeffrey 
Published: April 2007

AbstractRecent work has shown that physics‐based, all‐atom energy functions (AMBER, CHARMM, OPLS‐AA) and local minimization, when used in scoring, are able to discriminate among native and decoy structures. Yet, there have been only few instances reported of the successful use of physics based potentials in the actual refinement of protein models from a starting conformation to one that ends in structures, which are closer to the native state. An energy function that has a global minimum energy in the protein's native state and a good correlation between energy and native‐likeness should be able to drive model structures closer to their native structure during a conformational search. Here, the possible reasons for the discrepancy between the scoring and refinement results for the case of AMBER potential are examined. When the conformational search via molecular dynamics is driven by the AMBER potential for a large set of 150 nonhomologous proteins and their associated decoys, often the native minimum does not appear to be the lowest free energy state. Ways of correcting the potential function in order to make it more suitable for protein model refinement are proposed. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Poly(vinyl alcohol) (PVA)/sulfonated polyhedral oligosilsesquioxane (sPOSS) hybrid membranes for direct methanol fuel cell applications
Authors: Chang Young‐Wook , Wang Erdong , Shin Geumsig , Han Jung‐Eun , Mather Patrick T. 
Published: April 2007

AbstractOrganic/inorganic hybrid membranes based on poly(vinyl alcohol) (PVA) and sulfonated polyhedral oligosilsesquioxane (sPOSS), crosslinked by ethylenediaminetetraacetic dianhydride (EDTAD), were prepared as candidate materials for proton exchange membranes in direct methanel fuel cell (DMFC) applications. Fourier transform infrared (FT‐IR) spectroscopy and ion exchange capacity measurements for the prepared networks clearly revealed sPOSS incorporation. We found that proton conductivity increased and methanol permeability decreased with increasing sPOSS content in the hybrid membrane. In particular, our hybrid membranes demonstrated proton conductivities as high as 0.042 S/cm, which is comparable to that of Nafion™, while exhibiting two orders of magnitude lower methanol permeability as compared to Nafion™. We postulate that the polar sulfonic acid groups of the incorporated sPOSS cages assemble to provide ion conduction paths while the hydrophobic portions of the same sPOSS cages combine to form a barrier to methanol permeation with improved thermal stability of the hybrid membrane. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and characterization of a novel polytriazole resin with low‐temperature curing character
Authors: Tian Jianjun , Wan Liqiang , Huang Jianzhi , Hu Yanhong , Huang Farong , Du Lei 
Published: April 2007

AbstractA novel low‐temperature curing polytriazole resin was prepared from a triazide and a tetraalkyne and characterized. The resin can be cured at 70°C. The glass transition temperature Tg and thermal decomposition temperature Td5 of the cured resin with the molar ratio of azide to alkyne group [A]/[B] = 1.0:1.0 reached 324 and 355°C, respectively. The study on the curing kinetics of the resin shows that the apparent activation energy of the curing reaction is 93 kJ mol−1. The flexural strength of the cured resin reached 137.6 MPa at room temperature and 102.6 MPa at 185°C. Copyright © 2007 John Wiley & Sons, Ltd.
Altered cryptal expression of luminal potassium (BK) channels in ulcerative colitis
Authors: Sandle GI , Perry MD , Mathialahan T , Linley JE , Robinson P , Hunter M , MacLennan KA 
Published: April 2007

AbstractDecreased sodium (Na+), chloride (Cl−), and water absorption, and increased potassium (K+) secretion, contribute to the pathogenesis of diarrhoea in ulcerative colitis. The cellular abnormalities underlying decreased Na+ and Cl− absorption are becoming clearer, but the mechanism of increased K+ secretion is unknown. Human colon is normally a K+ secretory epithelium, making it likely that K+ channels are expressed in the luminal (apical) membrane. Based on the assumption that these K+ channels resembled the high conductance luminal K+ (BK) channels previously identified in rat colon, we used molecular and patch clamp recording techniques to evaluate BK channel expression in normal and inflamed human colon, and the distribution and characteristics of these channels in normal colon. In normal colon, BK channel α‐subunit protein was immunolocalized to surface cells and upper crypt cells. By contrast, in ulcerative colitis, although BK channel α‐subunit protein expression was unchanged in surface cells, it extended along the entire crypt irrespective of whether the disease was active or quiescent. BK channel α‐subunit protein and mRNA expression (evaluated by western blotting and real‐time PCR, respectively) were similar in the normal ascending and sigmoid colon. Of the four possible β‐subunits (β1–4), the β1‐ and β3‐subunits were dominant. Voltage‐dependent, barium‐inhibitable, luminal K+ channels with a unitary conductance of 214 pS were identified at low abundance in the luminal membrane of surface cells around the openings of sigmoid colonic crypts. We conclude that increased faecal K+ losses in ulcerative colitis, and possibly other diseases associated with altered colonic K+ transport, may reflect wider expression of luminal BK channels along the crypt axis. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The skimmiwallinols—minor components of the epicuticular wax of Cocos nucifera
Authors: Escalante‐Erosa Fabiola , Arvízu‐Méndez Gloria E. , Peña‐Rodríguez Luis M. 
Published: April 2007

AbstractFour new skimmiwallinol derivatives, isoskimmiwallinol acetate (4), skimmiwallinol acetate (5), isoskimmiwallinone (6) and skimmiwallinone (7), along with the previously isolated major components isoskimmiwallin (2) and skimmiwallin (3), have been found in the wax extract of pinnae from Cocos nucifera. Metabolites 4 and 5 were obtained as an inseparable mixture and identified by analysis of spectroscopic data and chemical correlation with 2 and 3, respectively. Metabolites 6 and 7 were identified by GC co‐injection with the corresponding synthetic derivatives prepared from 4 and 5. Copyright © 2007 John Wiley & Sons, Ltd.
Steady‐state analysis of emulsion polymerisation in a seeded, continuous stirred‐ tank reactor
Authors: Poehlein Gary W. , Dubner Walter , Lee Hsueh‐Chi 
Published: April 2007

AbstractA steady‐state model is presented for emulsion polymerisation in a continuous stirredtank reactor (CSTR) which is fed with a narrow particle‐size seed latex. The rather general kinetic model of Ugelstad et al 1,5 for monodisperse particles is applied to the polymerisation among latexes of broad particle size distribution in a CSTR.The model accounts for free radical absorption and desorption from the latex particles, for termination in the particles and the water phase, and for polymerisation within the particles. Results presented include the latex particle size distributions in the CSTR effluent stream and the number of free radicals per particle, averaged over these size distributions.
The glass transition and the glassy state in isotropic and liquid crystalline polymers
Authors: Rehage Günther , Frenzel Jürgen 
Published: April 2007

AbstractPVT‐measurements on atactic polystyrene shows that the Ehrenfest equations, which describe a thermodynamic transformation of the second order, are not applicable for the glass transition. The introduction of one internal ordering parameter ζ in addition to the conventional variables T and P, is sufficient to describe the behaviour in case of atactic PS in the isotropic glassy state. The usually observed way dependences in the glassy state can be explained by the concept of ordering parameters.In recent years liquid crystalline side chain polymers were developed. The liquid crystalline phases of these polymers can be supercooled and frozen‐in like isotropic liquids. As the nematic or smectic liquid crystalline structure freezes‐in, and can be conserved by this process, glasses with anisotropic properties are obtained. These glasses show e.g. a high optical birefringence.The glass transition of the liquid crystalline polymers can only be described by the assumption of at least two parameters ζi. Therefore the Ehrenfest equations are not applicable for the glass transition of isotropic as well as anisotropic glasses.
Epoxy systems with improved water resistance, and the non‐fickian behaviour of epoxy systems during water ageing
Authors: Johncock P. , Tudgey G. F. 
Published: April 2007

AbstractN,N‐Bis (2, 3‐epoxypropyl) aniline and 4,4′‐methylenebis‐[N,N‐bis (2,3‐epoxypropyl) aniline] containing bromo, chloro, trifluoromethyl or polyfluoroalkoxy substituents were synthesised and cured with aromatic diamines in order to investigate the effect of substituted halogen on water absorption. Significant improvements were achieved: thus use of 4,4′‐methylenebis‐[N, N‐bis (2, 3‐epoxypropyl)‐3, 5‐dichloroaniline] and 4,4′‐methylenebis‐[N,N‐bis (2,3‐epoxypropyl)‐3‐(trifluoromethyl) aniline] instead of 4,4′‐methylenebis‐[N,N‐bis (2,3‐epoxypropyl) aniline] reduced the water absorption by about a half. Departures from Fickian behaviour were observed during water immersion ageing at room temperature and were a general feature of the epoxy systems examined. Plots of water absorption against the Fickian parameter (√t/d) usually showed at least mild sigmoid character and were not independent of specimen thickness. Further, slow continued uptake of water occurred during long‐term ageing, and evidence is provided that the associated network distortions are reversible.