bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement and computation of ground resistances at 161/23.9–11.95‐kV indoor‐type substations
Authors: Chang Cheng‐Nan , Lee Chien‐Hsing , Wang Yaw‐Juen 
Published: March 2008

AbstractThe purpose of this paper is to compare the calculated and actual ground resistances at two 161/23.9–11.95‐kV indoor‐type substations in the system of Taiwan Power Company. For the calculated ground resistances, one‐ and two‐layer soil models based on Sverak and Schwarz equations, the method of images and the current distribution electromagnetic grounding and soil structure analysis (CDEGS) program are performed. As for the actual ground resistances, they are found by subtracting the measured ground resistances which are obtained by the fall‐of‐potential method from the earth mutual resistances. As a result, the calculated ground resistance based on the method of images as the observation point located at the lower layer of the two‐layer soil model is approximately equal to the actual ground resistance measured by the fall‐of‐potential method with the potential electrode buried at the lower layer. In addition, the ground potential rises (GPRs) at both substations are computed and compared with the minimum touch voltages for assessing the grounding system safety. The result shows that the design of the grounding system at both substations is unsafe under the one‐layer soil model for humans with 50 and 70 kg body weight. Copyright © 2008 John Wiley & Sons, Ltd.
Multiobjective distributed generation placement using fuzzy goal programming with genetic algorithm
Authors: Kim Kyu‐Ho , Song Kyung‐Bin , Joo Sung‐Kwan , Lee Yu‐Jeong , Kim Jin‐O 
Published: March 2008

AbstractThis paper presents a new method to determine the locations and sizes of Distributed Generations (DGs) for loss reduction and voltage profile enhancement in distribution systems. The strategic placement of DG can help reduce power losses and improve feeder voltage profile. Fuzzy Goal Programming (FGP) is adopted to handle the multiobjective DG placement problem incorporating the voltage characteristics of each individual load component. The original objective functions and constraints are transformed into the multiobjective function with fuzzy sets by FGP. The transformed multiobjective function with fuzzy sets represents the imprecise natures for criterion of loss reduction and voltage profile enhancement, and the number and total capacities of DGs. The solution of the transformed multiobjective function with fuzzy sets is searched by Genetic Algorithm (GA). The proposed method is tested on the IEEE 34‐bus system to demonstrate its effectiveness. Copyright © 2008 John Wiley & Sons, Ltd.
The transformer thermal loss of life: Part 2‐Influence of functional and structural parameters' variability. A probabilistic approach
Authors: Resende M. J. , Pierrat L. , Santana J. 
Published: March 2008

AbstractMain factors constraining transformers' thermal loss of life (LOL) are load and ambient temperature profiles they experience. Provided a suitable transformer thermal model and a LOL one are chosen, it is possible, from a theoretical point of view, to determine its on‐line expected LOL, as already presented in the first part of this work. However, due to the random character of constrains, such a purely deterministic approach will lead to reduced reliability results. The physical characteristics of the real profiles that transformers are subjected to (deterministic and random), and the uncertainty associated to transformer's specific parameters used in its thermal model, require a probabilistic approach for the study of expected LOL. This part of the work consists of two studies: the estimation of transformer LOL by considering statistical distributions for the load and ambient temperature profiles and the analysis of model's sensitivity to its structural parameters. Copyright © 2008 John Wiley & Sons, Ltd.
Systematic nonlinear control approach to a power factor corrector design
Authors: Sasaki Seigo 
Published: March 2008

AbstractA nonlinear controller for a power factor corrector is systematically constructedviaLyapunov‐based controller design approach for the bilinear state averaged model. First, a nonlinear gain of the controller is derived to shape the source current and the output voltage be desired form respectivelyvianonlinearH∞control system design approach. Second, a source current reference generator is constructed, which consists of a current feedforward loop given by a steady state analysis and a voltage feedback loop with an output voltage error amplifier. The design approach makes it clear that the tracking performance for the output voltage is achieved by generating an adequate source current reference. This paper finally shows efficiencies of the approach through computer simulations. Copyright © 2008 John Wiley & Sons, Ltd.
A power quality analysis scheme using adaptive subband decomposition
Authors: Ece Doğan Gökhan , Gerek Ömer Nezih 
Published: March 2008

AbstractIn this work, a new event detection method for power quality analysis based on the statistical analysis of adaptive decomposition signals is presented. The combination of an adaptive prediction filter‐based subband decomposition structure with a rule‐based histogram analysis block produced successful detection and classification parameters on our real life power system transient data. Proposed scheme is implemented using MATLAB™ Simulink DSP Blockset. Copyright © 2008 John Wiley & Sons, Ltd.
Risk‐based self‐scheduling for GenCos in the day‐ahead competitive electricity markets
Authors: Yamin H. Y. , Altawil I. A. , Al‐Ajlouni A. F. , Shahidehpour S. M. 
Published: March 2008

AbstractThis paper addresses the risk‐based self‐scheduling problem using a hybrid technique between Lagrangian relaxation (LR) and particle swarm optimizer (PSO). The paper analyses a self‐scheduling model that accounts for profit and risk simultaneously. The effect of risk is explicitly modelled in the self‐scheduling problem taking into account the variance of the market‐clearing prices. The forecasted hourly probabilities that spinning and non‐spinning reserves are called and generated are also considered in the formulation to simulate the reserve uncertainty. Artificial neural network (ANN) is applied for forecasting the hourly reserve probability. The proposed approach is applied to a 36 unit test system. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of lorazepam on visual perceptual abilities
Authors: Pompéia S. , Pradella‐Hallinan M. , Manzano G. M. , Bueno O. F. A. 
Published: March 2008

AbstractObjectiveTo evaluate the effects of an acute dose of the benzodiazepine (BZ) lorazepam in young healthy volunteers on five distinguishable visual perception abilities determined by previous factor‐analytic studies.MethodsThis was a double‐blind, cross‐over design study of acute oral doses of lorazepam (2 mg) and placebo in young healthy volunteers. We focused on a set of paper‐and‐pencil tests of visual perceptual abilities that load on five correlated but distinguishable factors (Spatial Visualization, Spatial Relations, Perceptual Speed, Closure Speed, and Closure Flexibility). Some other tests (DSST, immediate and delayed recall of prose; measures of subjective mood alterations) were used to control for the classic BZ‐induced effects.ResultsLorazepam impaired performance in the DSST and delayed recall of prose, increased subjective sedation and impaired tasks of all abilities except Spatial Visualization and Closure Speed. Only impairment in Perceptual Speed (Identical Pictures task) and delayed recall of prose were not explained by sedation.ConclusionAcute administration of lorazepam, in a dose that impaired episodic memory, selectively affected different visual perceptual abilities before and after controlling for sedation. Central executive demands and sedation did not account for results, so impairment in the Identical Pictures task may be attributed to lorazepam's visual processing alterations. Copyright © 2008 John Wiley & Sons, Ltd.
Preparation of SO42−/Fe2O3MoO3 and its catalytic activity in the electrolytic reaction of phenol with methanol
Authors: Zhu Zhigang , Wang Bo , Ma Hongzhu 
Published: March 2008

AbstractBACKGROUND: Environmentally friendly solid catalysts are important in many processes from an industrial point of view and are applied widely in the study of alkylation of phenol with methanol in gas phase. However, liquid‐phase reactions have not been well studied. This paper deals with an assessment of liquid‐phase electrolytic alkylation in the presence of SO42−/Fe2O3MoO3.RESULTS: A bidentate structure was formed between the SO42− and metal. A catalyst with an amorphous structure delivered lower catalytic activity even at a higher Mo content. The highest activity was obtained at an Mo content of 16% (molar composition), which delivered a phenol conversion of up to 70.5%. Experiments also showed that the catalyst can be reused at least for three times.CONCLUSION: Application of solid catalyst in the liquid‐phase reaction assisted by electrolysis alkylation was found to be viable. The main products were methoxyphenols, in contrast to that associated with gas‐phase operation. A possible mechanism of product formation has been proposed. Copyright © 2008 Society of Chemical Industry
New insights on late Quaternary palaeogeographic setting in the Northern Adriatic Sea (Italy)
Authors: Picone Sara , Alvisi Francesca , Dinelli Enrico , Morigi Caterina , Negri Alessandra , Ravaioli Mariangela , Vaccaro Carmela 
Published: March 2008

AbstractSedimentological, geochemical and micropalaeontological data from sediment cores in the northwestern Adriatic Sea were obtained to reconstruct the stratigraphic framework and palaeogeographic setting during the last post‐glacial sea‐level rise (14000–6000 yr BP). Four lithostratigraphic units were identified: (a) distal plain deposits (>14000 yr BP), submerged during the first phases of marine ingression; (b) coastal lagoon system; (c) barrier‐lagoon system, which is dated back to between 10019 ± 61 and 10228 ± 174 cal. yr BP from 14C dating on peat and shell remains; (d) marine prodelta deposits (<5500 yr BP). Geochemical data allow the identification of three distinct sediment sources: River Po, River Adige and Eastern Alpine rivers characterised by decreasing Ni/Mg ratios (50–70, 8–15 and 5–10, respectively) and Ba/Al ratios of 45–55, 55–65 and 35–45, respectively. The three sources display different relative abundances in time. During the Lateglacial, the Po is the main sediment source for the southern cores, whereas the Eastern Alps and the River Adige are the main sediment sources for the northern cores. This suggests a northern position of the Po River bed compared to previous studies. Coastal drowning led to a homogenization of the provenance signal within the sediments. Only after the marine transgression does a River Po signal appear in the northern cores. At the same time, in the southern cores the signal of Eastern Alpine rivers becomes stronger. Transgressive barrier‐lagoon and recent sediments do not display a predominant signal for provenance indicators. Copyright © 2008 John Wiley & Sons, Ltd.
Immobilization of Penicillin G Acylase on Poly[(glycidyl methacrylate)‐co‐(glycerol monomethacrylate)]‐Grafted Magnetic Microspheres
Authors: Huang Junsheng , Li Xiutao , Zheng Yanhui , Zhang Yong , Zhao Ruiying , Gao Xicai , Yan Husheng 
Published: March 2008

AbstractPoly[(glycidyl methacrylate)‐co‐(glycerol monomethacrylate)]‐grafted magnetic microspheres were prepared by graft random copolymerization via ATRP from polymer microspheres with dispersed Fe3O4 nanoparticles. Penicillin G acylase (PGA) was immobilized onto the polymer brush‐grafted magnetic microspheres. The immobilized PGA prepared with initial glycidyl methacrylate/ glycerol monomethacrylate ratios of 40/60 to 60/40 possessed higher catalytic activity than that prepared with higher proportions of glycidyl methacrylate in the initial monomer mixture. The immobilized PGA showed high thermal stability and enhanced tolerability to the pH variance.magnified image
Synthesis of Amine and Epoxide Telechelic Siloxanes
Authors: Chakraborty Ruby , Soucek Mark D. 
Published: March 2008

AbstractA synthetic route was developed to prepare thermosetting methyl, cyclopentyl, and cyclohexyl substituted polysiloxanes with epoxide or amino end groups. Cycloalkene (cyclopentene or cyclohexene) and dichlorosilane gas were reacted at 180 °C, and at high pressure (2 MPa) to produce dicycloaliphatic dichlorosilane. Hydrolytic condensations of the dichlorosilanes were performed affording low molecular weight cyclic siloxane oligomers. Base catalyzed ring opening polymerization of the cyclic oligomers afforded the hydride‐terminated polysiloxanes. The hydride‐terminated polysiloxanes were then functionalized with glycidyl epoxide or aliphatic amine groups via hydrosilation reactions. The oligomers and polymers were characterized by 1H NMR, 13C NMR, 29Si NMR, FTIR, and GPC. The molecular weight of polydimethylsiloxane, polydicyclopentylsiloxane, and polydicyclohexylsiloxane oligomers were $\overline M _{\rm n}$ = 1 000, 1 200, and 1 500, respectively. The polydispersity index of all the cyclic oligomers was ≈1.15. Differential scanning calorimetry (DSC) was used to evaluate the crosslinking reaction and the glass transition temperature of the thermally cured systems. Crosslinking occurred at 120 °C and the Tg of the methyl, cyclopentyl, and cyclohexyl functionalized siloxanes were found to be at −104, −93, and −82 °C, respectively.magnified image
Kinetic Study of D,L‐Lactide and Glycolide Homopolymerizations by Differential Scanning Calorimetry
Authors: Mazarro Rosario , de Lucas Antonio , Gracia Ignacio , Rodríguez Juan F. 
Published: March 2008

AbstractThe homopolymerizations of D,L‐lactide and glycolide catalyzed by ZnOct2 were studied by DSC. The kinetic parameters obtained are compared with those obtained from conversion data of bulk polymerizations. For the glycolide, the respective values of the calculated rate constants were quite similar. For the lactide polymerization, however, the agreement between the values obtained was not so good because the kinetics is affected by thermodynamics in the DSC experiments. As a result, the kinetics can not be studied by DSC. The degree of aggregation of the catalyst, the reaction order with respect to it, and the initiator influence were determined for glycolide homopolymerization.magnified image
Chemically Extracted Cornhusk Fibers as Reinforcement in Light‐Weight Poly(propylene) Composites
Authors: Huda Shah , Yang Yiqi 
Published: March 2008

AbstractFlexural, impact resistance, tensile, and sound absorption properties of composites from cornhusk fiber (CHF) and PP have been investigated. The effect of holding temperature, CHF length, CHF concentration, and enzyme treatment of CHF on mechanical properties and the effect of the latter two on sound absorption have been studied. Compared with jute/PP composites, CHF/PP composites have similar impact resistance, 33% higher flexural strength, 71% lower flexural modulus, 43% higher tensile strength, 54% lower tensile modulus, and slightly higher noise reduction coefficient. Enzyme treatment of CHF results in increased mechanical and sound absorption properties.magnified image
Porous Cellulose Acetate Butyrate Foams with a Tunable Bimodality in Foam Morphology Produced with Supercritical Carbon Dioxide
Authors: Jacobs Leon J. M. , Hurkens Stan A. M. , Kemmere Maartje F. , Keurentjes Jos T. F. 
Published: March 2008

AbstractPorous cellulose acetate butyrate foams with a bimodal cell size distribution were produced using supercritical carbon dioxide as a blowing agent. It is demonstrated that the cell size distribution is tunable, due to the semi‐crystalline nature of the polymer. The resulting morphology will either be homogeneous or bimodal, depending on the depressurization rate. Mercury intrusion porosimetry shows that the produced cellulose acetate butyrate foams possess an open cellular structure.magnified image
Isotactic Poly(propylene) Nanocomposites Based upon Boehmite Nanofillers
Authors: Streller Rouven C. , Thomann R. , Torno O. , Mülhaupt R. 
Published: March 2008

AbstractThe influence of boehmite crystallite sizes, varied between 10 and 60 nm, was studied with respect to the morphology development, crystallization behavior and mechanical properties of the boehmite‐based iPP nanocomposites. The nanometer‐scaled boehmites were formed during twin‐screw melt extrusion of iPP at 200 °C. Even in the absence of polymer compatibilizers, the boehmites, obtained from Sasol's process, enabled very effective deagglomeration and in‐situ dispersion of nanoboehmites. With increase in boehmite crystallite size it was possible to improve simultaneously stiffness and impact strength of iPP. As evidenced by means of DSC, POM and WAXS measurements, the deagglomerated nanoboehmites nucleated crystallization of poly(propylene)'s α‐modification.magnified image
Red Ionic Water‐Soluble Imidazolium‐Containing Polydiacetylene
Authors: Chougrani Kamel , Deschamps Jérome , Dutremez Sylvain , van der Lee Arie , Barisien Thierry , Legrand Laurent , Schott Michel , Filhol Jean‐Sébastien , Boury Bruno 
Published: March 2008

AbstractSynthesis of a water‐soluble polydiacetylene has been achieved by topochemical polymerization in the solid state of the bis(N‐methylimidazolium)diacetylene monomer. Structural characterization for the monomer by X‐ray diffraction and NMR spectroscopy supports a photopolymerization initiated at the surface. Characterization of the polymer (NMR, UV and Raman spectroscopy, and dynamic light scattering) is given along with a molecular modelling interpretation of the polymerization in the solid state.magnified image
Optical Non‐Linearity from Montmorillonite Intercalated with a Chromophore‐Containing Dendritic Structure: A Self‐Assembly Approach
Authors: Chen Yung‐Chung , Juang Tzong‐Yuan , Dai Shenghong A. , Wu Tzong‐Ming , Lin Jiang‐Jen , Jeng Ru‐Jong 
Published: March 2008

AbstractChromophore‐containing dendritic structures (G1, G2) are utilized to intercalate layered silicates, which results in a large d‐spacing up to 126 Å. An exfoliated morphology is obtained by mixing the dendritic structure intercalated layered silicates with polyimide in N,N‐dimethylacetamide solution. The dendritic structures attached on the clay template would arrange in a non‐centrosymmetric manner. This self‐assembled arrangement brought about the electro‐optical coefficients of 5–6 pm · V−1 for these relatively low chromophore‐containing organic/inorganic nanocomposites without resorting to poling. Excellent temporal stability (100 °C) is also achieved.magnified image
ATRP of Silylated Glycerol Monomethacrylate in Organic Medium for Convenient Synthesis of Amphiphilic Copolymers
Authors: Giacomelli Cristiano , Borsali Redouane 
Published: March 2008

AbstractA synthetic method with broad spectrum of application in the preparation of self‐organizing amphiphilic copolymers having poly(glycerol monomethacrylate) (PG2MA) as a hydrophilic part is herein reported. The approach relies on the facile preparation of silylated glycerol monomethacrylate (G2MA‐TMS) monomer, and its controlled atom transfer radical polymerization (ATRP) in organic media, which produced well‐defined (co)polymers with predictable molar mass and low dispersity, followed by desilylation. The wide scope of such a strategy was demonstrated by the successful synthesis of original polycaprolactone‐b‐poly(glycerol monomethacrylate) (PCL‐b‐PG2MA) diblock copolymers with the ability to self‐assemble into ordered structures (micelles and vesicles) in an aqueous medium.magnified image
A Facile Route to Synthesize Well‐Defined Polybutadiene DendriMacs
Authors: Kimani Solomon M. , Hutchings Lian R. 
Published: March 2008

AbstractA facile route to synthesize well‐defined polybutadiene (PBd) DendriMacs is described. In a highly modified approach to that recently published for the synthesis of polystyrene DendriMacs, a G1 polybutadiene (PBd) DendriMac has been synthesized in three simple and high yielding steps. The first step involves the synthesis of a three‐arm PBd mikto arm star in which one arm has a terminal hydroxy group introduced by the use of a protected functionalized initiator. Following fractionation of the star, the hydroxy group is deprotected and converted into an alkyl bromide moiety before coupling the star to a trifunctional core (1,1,1‐tris(4‐hydroxylphenyl)ethane) by a Williamson coupling reaction catalyzed by cesium carbonate to yield a G1 PBd DendriMac.magnified image
Knowledge acquisition and transfer among engineers: effects of network structure
Authors: Boone Tonya , Ganeshan Ram 
Published: March 2008

AbstractThis paper examines the association between the structure of formal intra‐firm networks and productivity. We focus on two network structure components—department centralization and centrality, within a four department engineering organization. Centrality indicates the number of connections between one department and others within the organization, while centralization captures how much of those connections are concentrated among the workers within the department. Both of these represent specific managerial decisions in a formal network structure. We use learning curve theory to measure accumulated organizational knowledge, its depreciation and intra‐firm transfers. We hypothesize that the departments are more productive, experience less depreciation and realize more knowledge transfer if they have more intra‐firm connections among more workers. The findings suggest a significant yet moderate association between the formal network structure and productivity. Copyright © 2008 John Wiley & Sons, Ltd.
On facet‐breaking for crystalline mean curvature flow in 3D
Authors: Bellettini Giovanni 
Published: March 2008

AbstractWe discuss the facet‐breaking phenomenon in crystalline mean curvature flow, and its connection with the prescribed curvature problem and the capillarity problem. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Level‐set techniques for microwave medical imaging
Authors: Irishina Natalia , Dorn Oliver , Moscoso Miguel 
Published: March 2008

AbstractMicrowave tomographic imaging is showing significant promise as a new technique for the early detection of breast cancer. Its physical basis is the contrast between the dielectric properties of the healthy breast tissue and the malignant tumors at microwave frequencies. We propose and analyze a novel shape‐reconstruction technique for the early detection of breast cancer from microwave data which is based on a level‐set technique. The advantages of this method compared to more traditional pixel‐based approaches are well‐defined boundaries and the incorporation of an intrinsic regularization in form of a‐priori assumptions about the general anatomical structure of breast that reduces the dimensionality of the inverse problem and thereby stabilizes the reconstruction. Our goal is not only to detect the tumors but to simultaneously determine their approximate locations, sizes and permittivity values. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)