bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of foaming temperature and rubber grades on properties of natural rubber foams
Authors: Ariff Z. M. , Zakaria Z. , Tay L. H. , Lee S. Y. 
Published: November 2007

AbstractFoaming temperature and grade of dry natural rubber were varied to evaluate their effects on the morphology and mechanical properties of natural rubber (NR) foams. Three different grades of NR were used; namely ENR‐25, SMR‐L, and SMR‐10. NR foams from these grades were produced at three different foaming temperatures, i.e. 140, 150, and 160°C. The study was carried out using formulated compositions containing sodium bicarbonate as the chemical blowing agent and were expanded using conventional compression molding technique via a heat transfer foaming process. The NR foams were characterized with respect to their relative foam density, density of crosslinking, cell size, compression stress, and compression set. Increase in foaming temperature resulted in lower relative density and larger cell size. It was also discovered that the crosslink density slightly decrease with increasing foaming temperature. For mechanical properties, the highest foam density resulted in the highest compression stress. Compression stress at 50% strain increased with increasing foaming temperature and ENR‐25 foam has the highest compression stress among the produced foams. The results showed that the morphology, physical, and mechanical properties of the rubber foams can be controlled closely by the foaming temperature and rubber grades. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Pilot test of prenatal surveillance for birth defects in South Texas
Authors: Ethen Mary K. , Canfield Mark A. , de Forest Peter , Trevino Jorge 
Published: November 2007

AbstractBACKGROUND:The Texas Birth Defects Registry (TBDR) does not access prenatal diagnostic facilities to ascertain cases. Objectives of the study were to determine how many cases may be missing from the registry as a result, and to assess the feasibility and utility of prenatal surveillance for birth defects, through a pilot test in one region of Texas.METHODS:A trained abstractor reviewed medical records of all patients with abnormal ultrasound findings during 2004 in all prenatal diagnostic facilities in Texas Health Region 11 (n = 6 facilities). When birth defects were prenatally detected, demographic and diagnostic data were abstracted. Prenatal abstractions were matched to cases in the TBDR. Those that did not match to registry cases were matched to vital records to determine where and when the pregnancy ended; delivery hospital medical records were reviewed for these cases.RESULTS:Approximately 760 patient charts were reviewed at prenatal diagnostic facilities and 365 were abstracted. Of these, 165 (45%) matched to cases in the TBDR. Delivery medical records were located and reviewed for 177 prenatal abstractions, with 170 (47%) indicating at delivery no defects monitored by the registry. Delivery records for one (0.3%) prenatal abstraction were not found by the hospital. Date and place of delivery were unknown for 22 (6%) prenatal abstractions. Only eight additional infants and fetuses (one twin pair) eligible for the registry were identified.CONCLUSIONS:For Texas Health Service Region 11, it is not necessary to conduct surveillance in prenatal diagnostic facilities, and to do so would be very labor‐intensive. Birth Defects Research (Part A) 79:788–791, 2007. © 2007 Wiley‐Liss, Inc.
Secondary structure inducing potential of β‐amino acids: Torsion angle clustering facilitates comparison and analysis of the conformation during MD trajectories
Authors: Guthöhrlein E. W. , Malešević M. , Majer Z. , Sewald N. 
Published: November 2007

AbstractWhile numerous examples of β‐peptides—exclusively composed of β‐amino acids—have been investigated during the past decade, there are only few reports on the conformational preference of a single β‐amino acid when incorporated into a cyclopeptide. The conformational bias of β‐amino acids on the secondary structure of cyclopeptides has been investigated by NMR spectroscopy in combination with distance geometry (DG) and molecular dynamics (MD) calculations using experimental constraints. The atomic coordinate RMSD criterion usually employed for clustering of conformations after DG and MD calculations does not necessarily group similar peptide conformations, as there is an insufficient correlation between atomic coordinates and torsion angles. To improve on this shortcoming and to eliminate any arbitrary decisions during this process, a torsion angle clustering procedure has been implemented. For the cyclic pentapeptides cyclo‐(‐Val‐β‐Hala‐Phe‐Leu‐Ile‐) 1 and cyclo‐(‐Ser‐Pro‐Leu‐β‐Hasn‐Asp‐) 3, the β‐amino acid is found in the central position of an extended γ‐turn (pseudo γ‐turn, Ψγ‐turn), while the β‐Hpro residue in the cyclic hexapeptide cyclo‐(‐Ser‐β‐Hpro‐Leu‐Asn‐Ile‐Asp‐) 5 preferentially occupies position i+1 of a pseudo β‐turn (Ψβ‐turn). These results further corroborate the hypothesis of β‐amino acids being reliable inducers of secondary structure in cyclic penta‐ and hexapeptides. They can be employed in the de novo design of biologically active cyclopeptides in pharmaceutical research, since the three‐dimensional presentation of pharmacophoric groups in the side chains can be tailored by incorporation of β‐amino acids in strategic sequential positions. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 829–839, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
The effects of translation and sex on hypnotizability testing
Authors: Cardeña Etzel , Kallio Sakari , Terhune Devin B. , Buratti Sandra , Lööf Angelica 
Published: November 2007

AbstractWe compared hypnotizability between two samples from different universities in Sweden. One test was administered in Swedish (University of Skövde) using a translated Swedish version of the HGSHS : A (Bergman, Trenter and Kallio, 2003). At Lund University, the original English version of the HGSHS : A (Shor and Orne, 1962) was used and participants also completed the Inventory Scale of Hypnotic Depth (ISHD; Field, 1965). The results suggest that administering the HGSHS : A in English to Swedish University students may only slightly reduce hypnotizability scores. Because the HGSHS : A was designed to be used for the initial screening of hypnotic suggestibility, for most practical purposes the original version seems a valid choice among non‐English groups fluent in English. The data also support some recent findings about females exhibiting higher objective and subjective hypnotizability scores than male volunteers. Copyright © 2007 British Society of Experimental & Clinical Hypnosis. Published by John Wiley & Sons, Ltd.
Determination of enantiomeric excess of ethyl 3,5‐dihydroxy‐6‐benzyloxy hexanoate by chiral reverse phase high performance liquid chromatography
Authors: Liu Ji‐Hua , Yu Bo‐Yang , Chen Yi‐Jun 
Published: November 2007

AbstractA simple and reliable chiral HPLC method was developed for the determination of enantiomeric excess of a chiral dihydroxy intermediate for the chemoenzymatic synthesis of side chain of statin drugs. After evaluating different columns and conditions, the four stereoisomers of ethyl 3,5‐dihydroxy‐6‐benzyloxy hexanoate were well resolved by a simple gradient elution on OD‐RH column, and the enantiomeric excess of the desired 3R,5S‐enantiomer was accurately measured. This study provides a simple, rapid, accurate, and reliable method to assess the enantiomeric quality of such important intermediates. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Computation of the J‐integral for large strains
Authors: Horváth Ágnes 
Published: November 2007

AbstractThe phenomenon of failure by catastrophic crack propagation in structural materials poses problems of design and analysis in many fields of engineering. Cracks are present to some degree in all structures. They may exist as basic defects in the constituent materials or they may be induced in construction or during service life.Using the finite element method, a lot of papers deal with the calculation of stress intensity factors for two‐ and three‐dimensional geometries containing cracks of different shapes under various loadings to elastic bodies. In order to increase the accuracy of the results, special elements have been used. They are described together with methods for calculating the stress intensity factors from the computed results.At the vicinity of a crack tip, the strains are not always small, but they may also be large. In this case, the J‐integral can also be applied to characterize the cracks in elastic or elastic–plastic bodies.This paper describes the computation of the two‐dimensional J‐integral for large strains to elastic and elastic–plastic bodies and represents some numerical examples. Copyright © 2007 John Wiley & Sons, Ltd.
Polynomial basis functions on pyramidal elements
Authors: Bluck M. J. , Walker S. P. 
Published: November 2007

AbstractPyramidal elements are necessary to effect the transition from tetrahedral to hexahedral elements, a common requirement in practical finite element applications. However, existing pyramidal transition elements suffer from degeneracy or other numerical difficulties, requiring, at the least, warnings and care in their use. This paper presents a general technique for the construction of nodal basis functions on pyramidal finite elements. General forms for basis functions of arbitrary order are presented. The basis functions so derived are fully conformal and free of degeneracy. Copyright © 2007 John Wiley & Sons, Ltd.
Two‐ and three‐dimensional growth modes of nitride layers
Authors: Pakuła K. , Baranowski J. M. , Borysiuk J. 
Published: November 2007

AbstractHeteroepitaxial three dimensional (3D) and two dimensional (2D) growth modes of nitride layers on sapphire substrates are discussed. It is shown that the 3D or 2D growth mode of AlGaN layers depends predominantly on the growth conditions of the underneath low temperature (LT) nucleation layer. Commonly described in literature 3D growth mode is achieved on LT GaN or AlN nucleation layer grown relatively fast. Successive growth of secondary layer at high temperature begins from separated sites, where individual 3D crystallites are formed. Threading dislocations present in crystallites bend on their facets, which reduces the quantity of dislocations. However, slight crystallographic misorientations between crystallites lead to the creation of new dislocations during coalescence of the crystallites. As a result, edge and mix dislocations appear at similar densities of about 109 cm‐2. Modification of growth conditions of LT AlN nucleation layer, especially reduction of their growth rate, leads to drastic changes in properties of the layer. Successive growth of secondary AlGaN layer at high temperature starts evenly on whole surface retaining atomic flatness. Thus growth at high temperature occurs only by 2D mode. Therefore, it is possible to grow a very thin AlGaN layers directly on top of LT nucleation layer. Such layers contain large number (1010 cm‐2) of edge dislocations, and relatively small number (less then 108 cm‐2) of mix dislocations. It is also shown that the decisive factor determining the growth mode of AlN nucleation layer is a growth of the first few atomic layers on substrate surface. The slow growth of these few first atomic layers decide about the 2D growth mode, and the fast one about the 3D one. The model explaining this difference is presented as well. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical investigation of crystal growth process of bulk Si and nitrides – a review
Authors: Kakimoto K. , Liu L. , Miyazawa H. , Nakano S. , Kashiwagi D. , Chen X. J. , Kangawa Y. 
Published: November 2007

AbstractHeat and mass transfer during crystal growth of bulk Si and nitrides by using numerical analysis was studied. A three‐dimensional analysis was carried out to investigate temperature distribution and solid‐liquid interface shape of silicon for large‐scale integrated circuits and photovoltaic silicon. The analysis enables prediction of the solid‐liquid interface shape of silicon crystals. The result shows that the interface shape became bevel like structure in the case without crystal rotation. We also carried out analysis of nitrogen transfer in gallium melt during crystal growth of gallium nitride using liquid‐phase epitaxy. The result shows that the growth rate at the center was smaller than that at the center. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A stability diagram for crystal growth from the vapor – a review
Authors: Grasza K. 
Published: November 2007

AbstractStability of the solid‐vapor interface is investigated. Surface roughening and evolution of flat faces at the growth interface is considered in terms of relation between gradient of temperature in the crystal and gradient of concentration in the vapor. Stability diagram is proposed, based on experimental data. The diagram summarizes the various forms and structures, which can be obtained using a typical system for growth from the vapor. The critical lines for constitutional supersaturation and appearance of low and high index faces were plotted. This attempt to the problem of stability of the growth interface differs from the former investigations mainly in looking for dependence between temperature field and concentration field rather than between more absolute parameters like temperature and supersaturation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preference for fcc atom stacking observed during growth of defect‐free LJ3281 clusters
Authors: Polak W. 
Published: November 2007

AbstractGrowth simulations of 3‐dimensional Lennard–Jones (LJ) clusters/nuclei from the vapor phase were carried out in order to estimate the role of kinetic and energetic effects in determining the internal structure of the clusters. The simulated growth was realized from N = 3281 up to ca. 10000 atoms at two reduced growth temperatures T* = 0.3 and 0.5 and the vapor atom concentration nv = 0.002 (in reduced units of LJ system). During growth at the low temperature, clusters evolve from octahedral to an irregular shape, while at the higher one they become spherical. Statistics of newly created structural units shows a strong preference for the formation of fcc units with their number approximately 3‐4 times larger than those of the hcp units. The possible explanation of this preference is by: (1) a larger surface diffusion leading to near spherical shape of clusters, (2) an energetic effect caused by different interaction energy of two fcc or hcp layers located on the neighboring {111} planes, and (3) an entropic effect in the form of disappearance of hcp island on the close‐packed fcc layers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Direct melt crystal growth of isotactic polybutene‐1 trigonal phase
Authors: Yamashita Motoi , Ueno Satoru 
Published: November 2007

AbstractThe morphology, crystalline structure and crystal growth kinetics of melt‐crystallized thin isotactic polybutene‐1 films have been studied with transmission electron microscopy, electron diffraction and optical microscopy. It is demonstrated that a bypass of tetragonal phase crystallization and direct melt crystal growth of the trigonal phase can be achieved via self‐seeding at atmospheric pressure using solution‐grown trigonal crystals as nuclei. Electron microscopy and optical microscopy observations show that melt‐crystallized isotactic polybutene‐1 single crystals of the trigonal phase have rounded or hexagonal morphologies around 75°C. The growth rate of trigonal crystals in the melt has been obtained by in‐situ optical microscopy. The growth rate of trigonal crystals in the melt is 1/100 and 1/1000 that of tetragonal crystals in the melt around 70 and 90°C, respectively. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Initial stages of SiC crystal growth by PVT method
Authors: Tymicki E. , Grasza K. , Diduszko R. , Bożek R. , Gała M. 
Published: November 2007

AbstractInitial stages of SiC crystal growth by Physical Vapor Transport method were investigated. The following features were observed: (a) many nucleation crystallization centres appeared on the seed surface during the initial stage of the growth, (b) at the same places many separate flat faces generated on the crystallization front, (c) the number of facets was dependent on the shape of the crystallization front and decreased during growth, (d) appearance of many facets lead to decrease of structural quality of crystals due to degradation of regions where crystallization steps from independent centres met. The results revealed that the optimal crystallization front should be slightly convex, which permits the growth of crystals with single nucleation centre and evolution of single facet on the crystallization front. The subjects of study were the shape and the morphology of growth interface. Defects in the crystallization fronts and wafers cut from the crystals were studied by optical microscopy, atomic force microscopy (AFM) combined with KOH etching and X‐ray diffraction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of growth kinetics and morphology of sodium fluorosilicate ice‐analogue crystals in solutions and gels
Authors: Krasiński M. J. , Krasińska K. R. , Ulanowski Z. 
Published: November 2007

AbstractThe effect of growth method (solution or gel growth) and growth conditions on the morphology of ice analogue crystals (sodium fluorosilicate) has been studied. Many habits typical for atmospheric ice crystals (hexagonal columns, plates, different types of stars or dendrites) were obtained during experiments. The dependence of growth rate of basal and prism faces of columnar crystals on supersaturation was measured for crystals growing by evaporation of solvent. The experiments establish evaporation rate and growth rate ranges at which appearance of certain types of crystals is most probable. The experiments have also shown that good quality sodium fluorosilicate crystals can be obtained in TMS gel. These crystals were significantly bigger than those obtained in solution. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the crucible bottom shape on the heat transport and fluid flow during the seeding process of oxide Czochralski crystal growth
Authors: Tavakoli M. H. , Wilke H. , Crnogorac N. 
Published: November 2007

AbstractFor the seeding process of oxide Czochralski crystal growth, influence of the crucible bottom shape on the heat generation, temperature and flow field of the system and the seed‐melt interface shape have been studied numerically using the finite element method. The configuration usually used in a real Czochralski crystal growth process consists of a crucible, active afterheater, induction coil with two parts, insulation, melt, gas and seed crystal. At first, the volumetric distribution of heat inside the metal crucible and afterheater inducted by the RF‐coil was calculated. Using this heat generation in the crucible wall as a source the fluid flow and temperature field of the entire system as well as the seed‐melt interface shape were determined. We have considered two cases, flat and rounded crucible bottom shape. It was observed that using a crucible with a rounded bottom has several advantages such as: (i) The position of the heat generation maximum at the crucible side wall moves upwards, compared to the flat bottom shape. (ii) The location of the temperature maximum at the crucible side wall rises and as a result the temperature gradient along the melt surface increases. (iii) The streamlines of the melt flow are parallel to the crucible bottom and have a curved shape which is similar to the rounded bottom shape. These important features lead to increasing thermal convection in the system and influence the velocity field in the melt and gas domain which help preventing some serious growth problems such as spiral growth. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and characterization of superconducting MgB2 rods
Authors: Orlińska N. , Zaleski A. , Paszula J. M. , Wokulski Z. 
Published: November 2007

AbstractSuperconducting Cu/Fe/MgB2 and Steel/Cu/MgB2 rods were prepared through the ex‐situ modified PIT technique with explosive consolidation method. The phase composition, microstructural features were investigated by X‐ray diffraction and scanning electron microscope. The AC susceptibility for a core samples was measured by the AC susceptometry. Measurements of the magnetization hysteresis loops were also carried out. It is found that no impurity phase was formed in MgB2 rods. In addition, it was found that grains in both Cu/Fe/MgB2 and Steel/Cu/MgB2 rods are densely packed. The magnetic measurements show that the critical temperature of Cu/Fe/MgB2 and Steel/Cu/MgB2 rods is 37.7 K and 37.6 K, respectively. The high critical current density of 9.22 × 105 A/cm2 (4.1 K, 0.2 T) was obtained for Steel/Cu/MgB2 rod. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallization of silicon thin films by current‐induced joule heating using a tungsten overcoat
Authors: Wu Gwo‐Mei , Wu Chen‐Yen 
Published: November 2007

AbstractA modified crystallization process using current‐induced joule heating under vacuum is presented. A thin layer of high temperature resistant tungsten was sputtered on the amorphous silicon as the conducting and annealing medium. The thin film thickness was measured by α‐stepper. The high current density provided effective means in crystallizing the amorphous silicon layer. The crystalline morphology was studied by scanning electron microscopy (SEM) after Secco‐etch, transmission electron microscopy (TEM), and x‐ray diffraction (XRD), under different annealing conditions. The grain size was controlled in the range of 0.1‐0.5 μm and could be increased with annealing time. No tungsten silicide was found. Some defects were formed due to electron‐migration effect near the electrodes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)