bluuebunny/crossref_metadata_2025_split huggingface dataset:
The w‐plane finite element method for the solution of the steady‐state scalar wave equation in two dimensions
Authors: Nath B. , Jamshidi J. 
Published: March 2007

AbstractA novel finite element method has been described in this paper for the solution of the steady‐state scalar wave equation in two dimensions. In this method the physical domain of the problem is mapped into an image domain; the governing equation and the prescribed boundary conditions are also appropriately transformed. Because logarithmic mapping functions are used, the physical domain is logarithmically condensed in the image plane. The method is therefore particularly suitable for the efficient and economical solution of large or very large aspect ratio problems.The high degree of accuracy which the method is capable of is demonstrated by means of two typical examples. Possible extension of the method to complex problems including non‐linearity, multiplicity, etc. is also discussed.
A model with non‐reflecting boundaries for use in explicit soil—structure interaction analyses
Authors: Kunar R. R. , Rodriguez‐Ovejero L. 
Published: March 2007

AbstractThe purpose of this paper is to present an accurate and efficient model for use in explicit soil‐structure interaction analyses for seismic excitation. The main body of the paper is concerned with the implementation of non‐reflecting boundaries at the base and vertical faces of a two‐dimensional finite element or finite difference soil mesh. The paper proposes a scheme for implementing viscous dashpots as energy absorbers at the base of the model where the seismic excitation is applied. To achieve this, the form of the seismic input is modified from the conventional accelerogram to a force time history that can be obtained from a standard deconvolution program with very minor modifications. The proposed scheme is also applicable to frequency‐domain solutions. For the lateral boundaries, a superposition non‐reflecting boundary formulation is recommended. The paper shows how easily the standard formulation can be modified to accommodate a seismic excitation that is assumed to be vertically propagating from the base of the model. An example is presented to demonstrate the accuracy of the proposed model.
Seismic damage estimation for low‐ and mid‐rise buildings in japan
Authors: Scawthorn C. , Iemura H. , Yamada Y. 
Published: March 2007

AbstractWhile much effort has been spent on analysis of individual structures, building class seismic damage estimators, of value in disaster planning, code‐writing, city planning, national hazards policy formulation, etc., have been little investigated. Based largely on data from Sendai City, Japan in the 12 June, 1978 Miyagiken‐oki earthquake (ML = 7.4), estimators of seismic damage for low‐ and mid‐rise buildings in urban Japan have been determined. For low‐rise buildings, based on damage to over 60,000 buildings, damage ratios for onset of damage and collapse and for cost of damage are found to correlate best with response spectra at 0.75 s. Using published test data and average building properties, a seismic damage model explains the low‐rise building behaviour and permits examination of the effect of structural changes on the estimated damage. For mid‐rise buildings, damage states (0: none, 4: total) are determined as a function of maximum storey displacement, based on published natural period determinations (pre‐ and post‐earthquake) for 189 mid‐rise buildings in Sendai. The effects of structural changes on expected damage can also be estimated. With these two building class damage estimators, a large part of future seismic damage to urban Japan can be estimated, as well as the effects of various mitigation measures.
A review of the response of buried pipelines under seismic excitations
Authors: Ariman Teoman , Muleski Gregory E 
Published: March 2007

AbstractModern cities depend heavily on utility systems for their day‐to‐day operation and earthquake threats to utility systems become increasingly important in proportion with the level of urbanization. Due to the great potential for destruction, damage and disruption, the seismic problems of utility systems have recently attracted researchers. It became apparent that the seismic behaviour of buried pipeline systems is quite different than that of above‐ground structures. In this paper, an updated and detailed review of the earthquake response and seismic‐resistant design of underground piping systems is presented.
Separation and sliding between soil and structure during strong ground motion
Authors: Toki Kenzo , Sato Tadanobu , Miura Fusanori 
Published: March 2007

AbstractThis paper presents an approach to the problem of separation and sliding between soil and structure in the finite element analysis of dynamic soil‐structure interaction problems. Joint elements are arranged along the contact surface between soil and structure and they have a property such that tensile forces are not transmitted between the planes representing structure and soil in the finite element analysis. The dynamic properties governing the sliding are determined by the Mohr‐Coulomb failure law determined from the cohesion and the friction angle between soil and structure.The proposed method is applied to (i) a model of a reactor building resting on the free surface of layered ground and (ii) a buried foundation structure. The numerical computations reveal the following results: that the translation is dominant in the motion of the structure when sliding is taking place between soil and structure, and that the rocking is dominant in the rest of the response. The amplitude of the response during sliding is increased on any one point of the structure and decreased on any one point of the ground compared with that of the fixed condition at the interface. In the case of the buried structure, it is observed in the computed results that the structure and soil move in the opposite direction along the vertical contact surface and are separated from each other in the near surface region during the strong phase of the excitation.
Earthquake analysis of concrete gravity dams including dam‐water‐foundation rock interaction
Authors: Chopra Anil K. , Chakrabarti P. 
Published: March 2007

AbstractA general procedure for analysis of the response of concrete gravity dams, including the dynamic effects of impounded water and flexible foundation rock, to the transverse (horizontal) and vertical components of earthquake ground motion is presented. The problem is reduced to one in two dimensions, considering the transverse vibration of a monolith of the dam. The system is analysed under the assumption of linear behaviour for the concrete, foundation rock and water.The complete system is considered as composed of three substructures—the dam, represented as a finite element system, the fluid domain, as a continuum of infinite length in the upstream direction, and the foundation rock region as a viscoelastic half‐plane. The structural displacements of the dam are expressed as a linear combination of Ritz vectors, chosen as normal modes of an associated undamped dam‐rock system. The effectiveness of this analytical formulation lies in its being able to produce excellent results by considering only a few Ritz vectors. The generalized displacements due to earthquake motion are computed by synthesizing their complex frequency responses using Fast Fourier Transform procedures. The stress responses are calculated from the displacements.An example analysis is presented to illustrate results obtained from this analytical procedure. Computation times for several analyses are presented to illustrate the effectiveness of the procedure.
Transient response of a thick beam of bimodular material
Authors: Bert C. W. , Tran A. D. 
Published: March 2007

AbstractCertain materials have different elastic behaviour when they are loaded in tension as compared to compression. As an engineering approximation, they are usually modelled as a bimodular material, i.e. a bilinear material having different Young's moduli in tension and in compression. All of the previous analyses of bimodular beams known to the present investigators have been concerned with either static loading or harmonic vibration. Thus, the present work is believed to be the first to consider transient response of such beams. The transfer‐matrix method is used to discretize spatially, while the timewise discretization is accomplished by use of the Newmark beta method.
Engineering analyses of smart 1 array accelerograms
Authors: Loh C. H. , Penzien J. , Tsai Y. B. 
Published: March 2007

AbstractPresented are the results of engineering analyses of selected accelerograms recorded by the SMART 1 strong motion array in Taiwan which is described in a companion paper by B. A. Bolt, Y. B. Tsai, K. Yeh and M. K. Hsu, entitled Earthquake Strong Motions Recorded by a Large Near‐source Array of Digital Seismographs. These analyses include (1) transformations to principal axes, (2) generation of Fourier amplitude spectra, (3) development of generalized response spectrum ratios for characterizing multi‐support excitations and (4) moving window analyses in the time and frequency domains for studying the spatial variations of recorded ground motions.
A friction damped base isolation system with fail‐safe characteristics
Authors: Kelly James M. , Beucke Karl E. 
Published: March 2007

AbstractAn experimental study of a Coulomb friction damped aseismic base isolation system with fail‐safe characteristics is described in this paper. The base isolation system utilized commercially made natural rubber bearings and a skid system which comes into operation at preset‐levels of relative horizontal displacement between the structure and the foundation. The fail‐safe skid provides hysteretic damping and prevents failure of the isolation system in the event of displacements larger than those assumed in the original design. The isolation system can be designed for an earthquake which can be reasonably expected within the lifetime of the structure; in the event of an earthquake of unanticipated intensity the failsafe system will prevent collapse of the structure.The testing of the system involved an 80,000lb model, approximately 1/3 scale to a real structure mounted on the 20′ × 20′ shaking table at EERC and subject to a variety of earthquake inputs. The results show that the hysteretic effect of the fail‐safe system does not greatly increase the accelerations experienced by the structure but considerably reduces the relative displacements at the isolation bearings. The action of the fail‐safe system was tested by using an earthquake input that produced a resonant response in the isolated mode of the model. The stability limit of the isolation system was exceeded and the bearings failed but complete failure of the isolation system and thus collapse of the model was prevented by the fail‐safe system. The implementation of the system in full scale structures poses no technical or construction problems.An equivalent linearization technique was developed for this system for design purposes using response spectra. The accuracy of this approach was verified by comparison with the experimental results.
Functional source separation applied to induced visual gamma activity
Authors: Barbati Giulia , Porcaro Camillo , Hadjipapas Avgis , Adjamian Peyman , Pizzella Vittorio , Romani Gian Luca , Seri Stefano , Tecchio Franca , Barnes Gareth R. 
Published: March 2007

AbstractObjective of this work was to explore the performance of a recently introduced source extraction method, FSS (Functional Source Separation), in recovering induced oscillatory change responses from extra‐cephalic magnetoencephalographic (MEG) signals. Unlike algorithms used to solve the inverse problem, FSS does not make any assumption about the underlying biophysical source model; instead, it makes use of task‐related features (functional constraints) to estimate source/s of interest. FSS was compared with blind source separation (BSS) approaches such as Principal and Independent Component Analysis, PCA and ICA, which are not subject to any explicit forward solution or functional constraint, but require source uncorrelatedness (PCA), or independence (ICA). A visual MEG experiment with signals recorded from six subjects viewing a set of static horizontal black/white square‐wave grating patterns at different spatial frequencies was analyzed. The beamforming technique Synthetic Aperture Magnetometry (SAM) was applied to localize task‐related sources; obtained spatial filters were used to automatically select BSS and FSS components in the spatial area of interest. Source spectral properties were investigated by using Morlet‐wavelet time‐frequency representations and significant task‐induced changes were evaluated by means of a resampling technique; the resulting spectral behaviours in the gamma frequency band of interest (20–70 Hz), as well as the spatial frequency‐dependent gamma reactivity, were quantified and compared among methods. Among the tested approaches, only FSS was able to estimate the expected sustained gamma activity enhancement in primary visual cortex, throughout the whole duration of the stimulus presentation for all subjects, and to obtain sources comparable to invasively recorded data. Hum Brain Mapp 29:131–141, 2008. © 2007 Wiley‐Liss, Inc.
Dp71ab/DAPs complex composition changes during the differentiation process in PC12 cells
Authors: Romo‐Yáñez J. , Ceja V. , Ilarraza‐Lomelí R. , Coral‐Vázquez R. , Velázquez F. , Mornet D. , Rendón A. , Montañez C. 
Published: March 2007

AbstractPC12 cells express different Dp71 isoforms originated from alternative splicing; one of them, Dp71ab lacks exons 71 and 78. To gain insight into the function of Dp71 isoforms we identified dystrophin associated proteins (DAPs) that associate in vivo with Dp71ab during nerve growth factor (NGF) induced differentiation of PC12 cells. DAPs expression was analyzed by RT–PCR, Western blot and indirect immunofluorescence, showing the presence of each mRNA and protein corresponding to α‐, β‐, γ‐, δ‐, and ε‐sarcoglycans as well as ζ‐sarcoglycan mRNA. Western blot analysis also revealed the expression of β‐dystroglycan, α1‐syntrophin, α1‐, and β‐dystrobrevins. We have established that Dp71ab forms a complex with β‐dystroglycan, α1‐syntrophin, β‐dystrobrevin, and α‐, β‐ and γ‐sarcoglycans in undifferentiated PC12 cells. In differentiated PC12 cells, the complex composition changes since Dp71ab associates only with β‐dystroglycan, α1‐syntrophin, β‐dystrobrevin, and δ‐sarcoglycan. Interestingly, neuronal nitric oxide synthase associates with the Dp71ab/DAPs complex during NGF treatment, raising the possibility that Dp71ab may be involved in signal transduction events during neuronal differentiation. J. Cell. Biochem. 102: 82–97, 2007. © 2007 Wiley‐Liss, Inc.
PPARβ agonists trigger neuronal differentiation in the human neuroblastoma cell line SH‐SY5Y
Authors: Di Loreto S. , D'Angelo B. , D'Amico M.A. , Benedetti E. , Cristiano L. , Cinque B. , Cifone M.G. , Cerù M.P. , Festuccia C. , Cimini A. 
Published: March 2007

AbstractNeuroblastomas are pediatric tumors originating from immature neuroblasts in the developing peripheral nervous system. Differentiation therapies could help lowering the high mortality due to rapid tumor progression to advanced stages. Oleic acid has been demonstrated to promote neuronal differentiation in neuronal cultures. Herein we report on the effects of oleic acid and of a specific synthetic PPARβ agonist on cell growth, expression of differentiation markers and on parameters responsible for the malignancy such as adhesion, migration, invasiveness, BDNF, and TrkB expression of SH‐SY5Y neuroblastoma cells. The results obtained demonstrate that many, but not all, oleic acid effects are mediated by PPARβ and support a role for PPARβ in neuronal differentiation strongly pointing towards PPAR ligands as new therapeutic strategies against progression and recurrences of neuroblastoma. J. Cell. Physiol. 211: 837–847, 2007. © 2007 Wiley‐Liss, Inc.
Inductively coupled plasma mass spectrometry (ICP MS): a versatile tool
Authors: Ammann Adrian A. 
Published: March 2007

AbstractInductively coupled plasma (ICP) mass spectrometry (MS) is routinely used in many diverse research fields such as earth, environmental, life and forensic sciences and in food, material, chemical, semiconductor and nuclear industries. The high ion density and the high temperature in a plasma provide an ideal atomizer and element ionizer for all types of samples and matrices introduced by a variety of specialized devices. Outstanding properties such as high sensitivity (ppt–ppq), relative salt tolerance, compound‐independent element response and highest quantitation accuracy lead to the unchallenged performance of ICP MS in efficiently detecting, identifying and reliably quantifying trace elements. The increasing availability of relevant reference compounds and high separation selectivity extend the molecular identification capability of ICP MS hyphenated to species‐specific separation techniques. While molecular ion source MS is specialized in determining the structure of unknown molecules, ICP MS is an efficient and highly sensitive tool for target‐element orientated discoveries of relevant and unknown compounds. This special‐feature, tutorial article presents the principle and advantages of ICP MS, highlighting these using examples from recently published investigations. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison of interpolation methods for mapping climatic and bioclimatic variables at regional scale
Authors: Attorre Fabio , Alfo' Marco , De Sanctis Michele , Francesconi Fabio , Bruno Franco 
Published: March 2007

AbstractClimatic data and bioclimatic indexes have been used to study plants, animals and ecosystem distribution. GIS‐based maps of climatic and bioclimatic data can be obtained by interpolating values observed at measurement stations. Since no single method can be considered as optimal for all observed regions, a major task is to propose comparisons between results obtained using different methods applied to the same data set of climate variables. We compared three methods that have been proved to be useful at regional scale: 1 ‐ a local interpolation method based on de‐trended inverse distance weighting (D‐IDW), 2 ‐ universal kriging (i.e. simple kriging with trend function defined on the basis of a set of covariates) which is optimal (i.e. BLUP, best linear unbiased predictor) if spatial association is present, 3 ‐ multilayer neural networks trained with backpropagation (representing a complex nonlinear fitting). Long‐term (1955–1990) average monthly data were obtained from weather stations measuring precipitation (201 sites) and temperature (102 sites). We analysed twelve climatic variables (temperature and precipitation) and nine bioclimatic indexes. Terrain variables and geographical location have been used as predictors of the climate variables: longitude, latitude, elevation, aspect, slope, continentality and estimated solar radiation. Based on the root mean square errors from cross‐validation tests, we ranked the best method for each variable data set. Universal kriging with external drift obtained the best performances for seventeen variables of the twenty‐one analysed, neural network interpolator has proven to be more efficient for three variables and D‐IDW for only one. Based on these results, we used the universal kriging estimates to produce the climatic and bioclimatic maps aimed at defining the bioclimatic envelope of species. Copyright © 2007 Royal Meteorological Society
A comparative study of composition and postharvest performance of organically and conventionally grown kiwifruits
Authors: Amodio Maria L , Colelli Giancarlo , Hasey Janine K , Kader Adel A 
Published: March 2007

AbstractPostharvest performance of organic and conventional ‘Hayward’ kiwifruits grown on the same farm in Marysville, California, and harvested at the same maturity stage were compared in this study. Quality parameters monitored included morphological (shape index) and physical (peel characteristics) attributes of the initial samples. Maturity indices (CO2 and C2H4 production, firmness, color, soluble solids content and acidity) and content of compounds associated with flavor and nutritional quality (minerals, sugars and organic acids, ascorbic acid, total phenolics, and antioxidant activity) were determined at 0, 35, 72, 90 and 120 days of storage at 0°C, and after 1 week of shelf‐life simulation at 20°C, after each storage duration. Organically and conventionally grown kiwifruits had similar soluble solids content at harvest, but conventional kiwifruits had a higher firmness and L* value, and a lower hue angle and chromaticity, resulting in a lighter green color when compared with the organic kiwifruits. These differences were maintained for all the storage durations, with the soluble solids content increasing more in conventionally grown kiwifruits. The two production systems resulted in different morphological attributes since organic kiwifruits exhibited a larger total and columella area, smaller flesh area, more spherical shape, and thicker skin compared to conventional kiwifruits. All the main mineral constituents were more concentrated in organic kiwifruits, which also had higher levels of ascorbic acid and total phenol content, resulting in a higher antioxidant activity. Sugars and organic acids composition was not affected by the production system. Copyright © 2007 Society of Chemical Industry
Hydrophilic surface modification of cyclic olefin copolymer microfluidic chips using sequential photografting
Authors: Stachowiak Timothy B. , Mair Dieudonne A. , Holden Tyler G. , Lee L. James , Svec Frantisek , Fréchet Jean M. J. 
Published: March 2007

AbstractThe plastic material known as cyclic olefin copolymer (COC) is a useful substrate material for fabricating microfluidic devices due to its low cost, ease of fabrication, excellent optical properties, and resistance to many solvents. However, the hydrophobicity of native COC limits its use in bioanalytical applications. To increase surface hydrophilicity and reduce protein adsorption, COC surfaces were photografted with poly(ethylene glycol) methacrylate (PEGMA) using a two‐step sequential approach: covalently‐bound surface initiators were formed in the first step and graft polymerization of PEGMA was then carried out from these sites in the second step. Contact angle measurements were used to monitor and quantify the changes in surface hydrophilicity as a function of grafting conditions. As water droplet contact angles decreased from 88° for native COC to 45° for PEGMA‐grafted surfaces, protein adsorption was also reduced by 78% for the PEGMA‐modified COC microchannels as determined by a fluorescence assay. This photografting technique should enable the use of COC microdevices in a variety of bioanalytical applications that require minimal nonspecific adsorption of biomolecules.
Miscibility and Phase Morphology of MF/PVAc Hybrid Resins for Surface Bonding of Building Interior Materials
Authors: Kim Sumin , Kim Hyun‐Joong 
Published: March 2007

AbstractThe objective of this research was to investigate the miscibility behavior of melamine‐formaldehyde resin and poly(vinyl acetate) blends for use as adhesives for surface materials in order to reduce formaldehyde emission. The investigation was conducted using differential scanning calorimetry, Fourier transform infrared spectroscopy, 13C CP/MAS solid state NMR, scanning electron microscope, atomic force microscopy and wide‐angle X‐ray scattering. Blends of various MF resin/PVAc weight compositions, comprising 0, 30, 50, 70 and 100%, were prepared in order to determine and compare the effect of PVAc content. These blends displayed a single cure temperature over the entire range of compositions indicating that this blend system was miscible in the amorphous phase due to the formation of hydrogen bonding between the amine groups of the MF resin and the carbonyl groups of PVAc. On the surface of the cured blends, the homogeneous dispersion of the PVAc phase in the MF resin was evident as small spherical domains and the blends were confirmed to be well combined.magnified image