bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel cooling channel shapes in pressure die casting
Authors: Clark L. D. , Davey K. , Hinduja S. 
Published: August 2002

AbstractThe pressure die casting involves die designs incorporating cooling channels positioned to facilitate the controlled extraction of energy from a solidifying casting. It is now known that subcooled nucleate boiling can occur in cooling channels and this paper is concerned with novel cooling channel shapes that are optimized to promote and enhance this boiling and thus reduce casting times. Shape sensitivity analysis is applied to a boundary element model using the material derivative adjoint variable technique. Mesh node positions on the cooling channels are used as the design parameters. The sensitivities are used in a conjugate gradient non‐linear optimization routine. It is shown that with this approach cooling channels can be designed to maximize boiling heat transfer whilst at the same time allow some degree of control of spatial temperature variation over the die cavity surface. Simulation and experimental results are presented for a traditional die and an optimized die. A 60 per cent reduction in cycle time is achieved with the optimized die. Copyright © 2001 John Wiley & Sons, Ltd.
Free vibrations of shear‐flexible and compressible arches by FEM
Authors: Litewka Przemyslaw , Rakowski Jerzy 
Published: August 2002

AbstractThe purpose of this paper is to analyse free vibrations of arches with influence of shear and axial forces taken into account. Arches with various depth of cross‐section and various types of supports are considered. In the calculations, the curved finite element elaborated by the authors is adopted. It is the plane two‐node, six‐degree‐of‐freedom arch element with constant curvature. Its application to the static analysis yields the exact results, coinciding with the analytical ones. This feature results from the use of the exact shape functions in derivation of the element stiffness matrix. In the free vibration analysis the consistent mass matrix is used. It is obtained on the base of the same functions. Their coefficients contain the influences of shear flexibility and compressibility of the arch. The numerical results are compared with the results obtained for the simple diagonal mass matrix representing the lumped mass model. The natural frequencies are also compared with the ones for the continuous arches for which the analytically determined frequencies are known. The advantage of the paper is a thorough analysis of selected examples, where the influences of shear forces, axial forces as well as the rotary and tangential inertia on the natural frequencies are examined. Copyright © 2001 John Wiley & Sons, Ltd.
Toward large scale F.E. computation of hot forging process using iterative solvers, parallel computation and multigrid algorithms
Authors: Mocellin K. , Fourment L. , Coupez T. , Chenot J. L. 
Published: August 2002

AbstractThe industrial simulation code Forge3® is devoted to three‐dimensional metal forming applications. This finite element software is based on an implicit approach. It is able to carry out the large deformations of viscoplastic incompressible materials with unilateral contact conditions. The finite element discretization is based on a stable mixed velocity–pressure formulation and tetrahedral unstructured meshes. Central to the Newton iterations dealing with the non‐linearities, a preconditioned conjugate residual method (PCR) is used. The parallel version of the code uses an SPMD programming model and several results on complex applications have been published. In order to reduce the CPU time computation, a new solver has been developed which is based on multigrid theory. A detailed presentation of the different elements of the method is given: the geometrical approach based on embedded meshes, the direct resolution of the velocity–pressure system, the use of PCR method as an original smoother and for solving the coarse problem, the full multigrid method and the required preconditioning by an incomplete Cholesky factorization for problems with complex contact conditions. By considering different forging cases, the theoretical properties of the multigrid method are numerically verified, optimizations of the solver are presented and finally, the results obtained on several industrial problems are given, showing the efficiency of the new solver that provides speed‐up larger than 5. Copyright © 2001 John Wiley & Sons, Ltd.
Development of an instrument to measure patient perception of the quality of nursing care
Authors: Dozier Ann M. , Kitzman Harriet J. , Ingersoll Gail L. , Holmberg Sharon , Schultz Alison W. 
Published: August 2002

AbstractAlthough patient satisfaction has been given considerable attention in health care, analysis of the conceptual and measurement limitations of existing measures indicates that a more elemental approach to obtaining patients' perspectives is warranted. In this investigation we developed and evaluated the psychometric properties of an instrument designed to measure patients' perceptions of the degree to which their needs were met while hospitalized. This 15‐item instrument, Patient Perception of Hospital Experience with Nursing (PPHEN), based on Swanson‐Kauffman's framework of caring, is internally consistent and represents a single construct best described as feeling cared for. The relationship of PPHEN to other measures demonstrates concurrent validity; moreover, the scale is responsive to differences in care provided, as shown by differences in means for different hospitals. PPHEN offers a brief, theoretically oriented, internally consistent, and valid patient self‐report measure of nursing care. It does not require patients to compare their expectations of care with the care received but only to evaluate whether their needs were met. It promises to be useful to clinical and health services researchers. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24:506–517, 2001
Popular participation and local government reform
Authors: Charlick Robert B. 
Published: August 2002

AbstractDoes decentralization, and particularly the creation of democratically elected local government, broaden mass political participation and make local government more effective and responsive? Evidence from two African Countries that have ‘democratized’ to varying degrees and through different approaches, this study makes two major points. First, although many of the hypotheses and initial findings of the Cornell Participation Project regarding the role of local organizations may still be valid, they remain largely untested in much of Africa because local government reform has been so limited and so recent. Second, in the limited number of cases where reform of local government has occurred in Africa, popular participation directed toward these governments can make them more responsive. This is only true, however, under particular circumstances, notably where projects with strong local and international non‐governmental organizational support chose to link to local government as well as to exert influence over policy at other levels of the political system. The fear expressed by some ‘civil society’ actors that the focus on local government may be narrowing the opportunities of non‐governmental associations to influence development policies is not confirmed in these cases. Copyright © 2001 John Wiley & Sons, Ltd.
Part 3. Copolymers of 1H,1H,2H,2H‐perfluorodecyl acrylate and 2,2,2‐trifluoroethyl methacrylate with butyl methacrylate
Authors: Lazzari Massimo , Chiantore Oscar , Castelvetro Valter 
Published: August 2002

AbstractCopolymers of 2,2,2‐trifluoroethyl methacrylate, or 1H,1H,2H,2H‐perfluorodecyl acrylate (XFDA) and butyl methacrylate (BMA) have been irradiated in air under artificial solar light and their photo‐oxidative stability has been investigated. Molecular and chemical changes occurring during the treatments have been monitored by weight loss and gel content determination, size exclusion chromatography and FTIR spectroscopy. It has been determined that the overall behaviour of both copolymers is controlled by the BMA units, independently of the total fluorine content. The photo‐ageing takes place mainly via the mechanism of oxidation of methacrylic polymers containing long side ester groups, whose flexibility favours macroradical coupling reactions. The tendency to crosslink is balanced only in the case of the initial stages of degradation of XFDA/BMA by the scission reactions derived from the direct attack of oxygen on the fluorinated acrylic units.© 2001 Society of Chemical Industry
Bending behaviour of electroresponsive poly(vinyl alcohol)/poly(acrylic acid) semi‐interpenetrating network hydrogel fibres under an electric stimulus
Authors: Fei Jiainqi , Zhang Zipeng , Gu Lixia 
Published: August 2002

AbstractPoly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) composite fibres were prepared via solution spinning and subsequently, semi‐interpenetrating networks (SIPN) were obtained by crosslinking the fibres with glutaraldehyde. The hydrogel fibres exhibited bending behaviour under DC electric stimulation. The effects of a number of factors have been systematically studied, including the PAA content within the network, electric voltage imposed across the fibre, the fibre diameter, concentration of the crosslinking agent, pH and ionic strength of the bath solution. Our experimental results show a stable reversibility of bending behaviour under the applied electric field. The degree of bending at equilibrium and the bending speed of the hydrogel fibre increased with the intensity of the applied electric voltage and the PAA content having negatively charged ionic groups within the SIPN. The electroresponsive behaviour of the present SIPN hydrogel fibre was also affected by the aforementioned extrinsic factors. These observations are interpreted in terms of fibre stiffness, fixed charge density and swelling pressure, which depend on the hydrogel equilibrium states in different pH and ionic environments together with the electrochemical reactions under DC electric field.© 2002 Society of Chemical Industry
Acid‐catalyzed hydrolysis of bridged bi‐ and tricyclic compounds. XXXVIII—Kinetics and mechanisms of 1‐ and 3‐nortricyclanols
Authors: Lajunen Martti , Lahti Veli 
Published: August 2002

AbstractThe disappearance of 1‐ and 3‐nortricyclanols (1‐OH and 2‐OH) in aqueous perchloric acid was followed by capillary GC at different temperatures and acid concentrations. 1‐OH is ca 1000 times more reactive than 2‐OH. The activation parameters, solvent deuterium isotope effects and parameters of excess acidity equations were measured and the products were studied. Both isomeric nortricyclanols react according to the AdE2 mechanism, i.e. the cyclopropane ring is protonated at the rate‐determining stage of the reaction. The protonation causes, in the case of 1‐OH, an isomerization called homoketonization with 2‐norbornanone as the only product and, in the case of 2‐OH, hydration, i.e. the formation of hydroxyl‐substituted norbornyl cations, the fast attack of which by water produces several norbornanediols. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of hydroxy‐terminated, oligomeric poly(silarylene disiloxane)s via rhodium‐catalyzed dehydrogenative coupling and their use in the aminosilane–disilanol polymerization reaction
Authors: Homrighausen Craig L. , Keller Teddy M. 
Published: August 2002

AbstractA series of oligomeric, hydroxy‐terminated silarylene–siloxane prepolymers of various lengths were prepared via dehydrogenative coupling between 1,4‐bis(dimethylsilyl)benzene [H(CH3)2SiC6H4Si(CH3)2H] and excess 1,4‐bis(hydroxydimethylsilyl)benzene [HO(CH3)2SiC6H4Si(CH3)2OH] in the presence of a catalytic amount of Wilkinson's catalyst [(Ph3P)3RhCl]. Attempts to incorporate the diacetylene units via dehydrogenative coupling polymerization between 1,4‐bis(dimethylsilyl)butadiyne [H(CH3)2SiCCCCSi(CH3)2H] and the hydroxy‐terminated prepolymers were unsuccessful. The diacetylene units were incorporated into the polymer main chain via aminosilane–disilanol polycondensation between 1,4‐bis(dimethylaminodimethylsilyl)butadiyne [(CH3)2NSi(CH3)2CCCC(CH3)2SiN(CH3)2] and the hydroxy‐terminated prepolymers. Linear polymers were characterized by Fourier transform infrared, 1H and 13C NMR, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis, and they were thermally crosslinked through the diacetylene units, producing networked polymeric systems. The thermooxidative stability of the networked polymers is discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1334–1341, 2002
FTIR, 13C NMR, and GPC analysis of high‐propylene content co‐ and terpolymers with ethylene and higher α‐olefins synthesized with EtInd2ZrCl2/MAO
Authors: Ferreira M. L. , Galland G. B. , Damiani D. E. , Villar M. A. 
Published: August 2002

AbstractThis article reports the results of propylene/α‐olefin copolymerization and propylene/ethylene/α‐olefin terpolymerization using low concentrations (less than 5 mol %) of long α‐olefins such as 1‐octene, 1‐decene, and 1‐dodecene. Kinetics data are presented and discussed. The highest activity was found with the longest α‐olefin studied (1‐dodecene). A possible explanation is proposed for this and other characteristics of the polymers obtained. The effect of low‐ethylene contents (4 mol % in the gas phase) on the copolymerization of propylene/α‐olefins was also examined. The polymers synthesized were characterized by 13C NMR, gel permeation chromatography, DSC, Fourier transform infrared spectroscopy, and wide‐angle X‐ray scattering. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2005–2018, 2001
Syndiospecific polymerization of styrene with BzCpTiCl3 and methylaluminoxane as cocatalysts
Authors: Schwecke Constantin , Kaminsky Walter 
Published: August 2002

AbstractBenzyl cyclopentadienyl titanium trichloride (BzCpTiCl3) was synthesized from benzyl bromide, cyclopentadienyl lithium, and titanium tetrachloride and used in combination with methylaluminoxane (MAO) for the syndiospecific polymerization of styrene. Kinetic measurements of the polymerization were carried out at different temperatures. The polymerization with BzCpTiCl3/MAO differs from the polymerization with cyclopentadienyl titanium trichloride in its behavior toward the Al/Ti ratio. In addition, high activities are observed at high Al/Ti ratios. By analyzing the polymerization runs and the physical properties of the polymers with differential scanning calorimetry, 13C NMR spectroscopy, wide‐angle X‐ray scattering measurements, and gel permeation chromatography, we found that the phenyl ring coordinates to the titanium atom during polymerization. Other known substitutions of the cyclopentadienyl ring (V. Scholz, Dissertation, University of Hamburg, 1998) in principle influence the polymerization activity. The physical properties of the polymers produced by the catalysts already known are nearly identical. BzCpTiCl3 is the first catalyst that leads to polystyrene obviously different from the polystyrene produced by other highly active catalysts. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2805–2812, 2001
Two mechanisms of the fragmentation of thin coatings on rubber substrates
Authors: Bazhenov S. L. , Volynskii A. L. , Alexandrov V. M. , Bakeev N. F. 
Published: August 2002

AbstractThe fragmentation of thin platinum films, nanometers thick, deposited on isoprene rubber and poly(ethylene terephthalate) substrates was studied. Light and scanning electron microscopy was used. The length of a fragment depends on the thickness of the coating film and the tensile stress applied to the specimen. An equation describing the tensile stress in an elastic coating fragment is derived. The equation is used to analyze the fragmentation of a coating film under tension. Two stages of fragmentation are distinguished. At low strains, when the length of the fragments is lower than the ineffective length, fragmentation is occasional, as determined by defects in the coating. At high strains, the mechanism of fragmentation changes to the division of the fragments into halves. The division repeats when the load is doubled. During this stage of fragmentation, the crack density is proportional to the applied stress and reversibly proportional to the thickness of the coating. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 10–18, 2002
Network formation studied by temperature scanning brillouin scattering and differential scanning calorimetry techniques. II.
Authors: Castiglia S. R. V. , Fioretto D. , Verdini L. , Samios D. 
Published: August 2002

AbstractThe reaction of 1,4‐butanediol diglycidyl ether (EP) with cis‐1,2‐cyclohexanedicarboxylic anhydride (CH) and triethylamine (TEA) as an initiator was studied with temperature scanning Brillouin spectroscopy (TSBS) and differential scanning calorimetry (DSC). The evolution of the reaction process (liquid–gel–solid) was investigated as a function of the epoxy molar fraction (xEP), for sample compositions varying from an epoxy excess to an anhydride excess. The dependence of the final conversion factors αrDSC and αrTSBS and the kinetic parameters EDSC and ETSBS on xEP is presented. A comparison of the experimental gelation point (Pgel) behavior and the expected theoretical one, described by the Flory theory, is also reported. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1326–1336, 2001
Unexpectedly high young's moduli recorded for iPP/HDPE blends
Authors: Finlay J. , Sheppard S. , Tookey S. , Hill M. J. , Barham P. J. 
Published: August 2002

AbstractYoung's moduli of a series of quenched isotactic polypropylene/high‐density polyethylene blends were measured. The moduli of many of the blends exceeded the upper bound, calculated from the parallel model with the moduli of the two quenched homopolymers as those of the two components. In fact, both components crystallized at higher temperatures in the blends than they did on their own. It is argued that the higher crystallization temperatures of the components lead to higher component moduli and that this can explain the observation that the measured moduli of the blends apparently exceeded the upper bound. The implications of this work are discussed in light of other studies concerning the measurement and calculation of blend moduli. © 2001 John Wiley & Sons, Inc. J Polym Sci B Part B: Polym Phys 39: 1404–1414, 2001
Specific interaction governing the melt intercalation of clay with poly(styrene‐co‐acrylonitrile) copolymers
Authors: Lee Sang‐Soo , Lee Choon Soo , Kim Myong‐Hoon , Kwak Seung Yup , Park Min , Lim Soonho , Choe Chul Rim , Kim Junkyung 
Published: August 2002

AbstractIn the melt intercalation of cation‐exchange clay, mixtures of montmorillonite and poly(styrene‐co‐acrylonitrile) (SAN) with various acrylonitrile contents were studied to examine the effect of specific interaction. When organic molecules with hydroxyl groups were used as intercalants for the clay, the amount of SAN penetrating the gallery of the layered structure of the clay and the corresponding increase in the gallery height occurred at a much higher rate because of the attractive specific interaction between acrylonitrile groups and polar groups on the clay surface. However, there was a limit to the increase in the gallery height, and the tendency for the gallery height to increase with the acrylonitrile group content disappeared when the acrylonitrile content was greater than 30 wt %, implying that excessive attractive interaction on the clay surfaces and polymer molecules glued the two adjacent silicate layers together; consequently, the increase in the gallery height could not be accomplished. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2430–2435, 2001
The flare in alkaline phosphatase activity post‐orchidectomy predicts which patient may benefit from early chemotherapy in metastatic prostate cancer
Authors: Pelger Rob C.M. , Lycklama À Nijeholt Guus A.B. , Zwinderman Aielko H. , Hamdy Neveen A.T. 
Published: August 2002

AbstractBACKGROUNDA flare in serum alkaline phosphatase (ALP) activity post‐orchidectomy has been shown to be of negative prognostic value for progression‐free survival (PFS) in patients with prostate cancer. The aim of this study was to investigate whether a flare in ALP may help identify patients in whom prognosis could be positively influenced by early chemotherapy.METHODSA retrospective analysis of the database of a Dutch multicenter study was conducted to evaluate the prognostic value of the flare in ALP post‐orchidectomy for survival and PFS in 112 patients treated with orchidectomy (previously reported) compared to 121 age‐ and stage‐matched patients additionally treated with estramustine‐phosphate (EMP) as first line therapy.RESULTSThere was no overall difference in PFS and survival between the two treatment regimen. Subgroup analysis of patients demonstrating a greater than 50% increase in ALP post‐orchidectomy showed, however, a significant increase in PFS in patients additionally treated with EMP.CONCLUSIONSOur data suggest that the simple measurement of ALP activity within 4 weeks of castration represents a useful adjunct in assessing which patients with prostate cancer undergoing androgen ablation may benefit from additional early chemotherapy. Prostate 50: 119–124, 2002. © 2002 Wiley‐Liss, Inc.
Study of the conformational profile of the norbornane analogues of phenylalanine
Authors: Cordomí Arnau , Gomez‐Catalan Jesus , Jimenez Ana I. , Cativiela Carlos , Perez Juan J. 
Published: August 2002

AbstractThe conformational profile of the eight stereoisomeric 2‐amino‐3‐phenylnorbornane‐2‐carboxylic acids (2‐amino‐3‐phenylbicyclo[2.2.1]heptane‐2‐carboxylic acids) has been assessed by computational methods. These molecules constitute a series of four enantiomeric pairs that can be considered as rigid analogues of either L‐ or D‐phenylalanine. The conformational space of their N‐acetyl methylamide derivatives has been explored within the molecular mechanics framework, using the parm94 set of parameters of the AMBER force field. Local minimum energy conformations have been further investigated at the ab initio level by means of the Hartree‐Fock and second order Moller‐Plesset perturbation energy calculations using a 6–31G(d) basis set.The results of the present work suggest that the bulky norbornane structure induces two kinds of conformational constraints on the residues. On one hand, those of a steric nature directly imposed by the bicycle on the peptide backbone and, on the other hand, those that limit the orientations attainable by the phenyl ring which, in turn, reduces further the flexibility of the peptide backbone. A comparative analysis of the conformational profile of the phenylnorbornane amino acids with that of the norbornane amino acids devoid of the β‐phenyl substituent suggests that the norbornane system hampers the residue to adopt extended conformations in favour of C7‐like structures. However, the bicycle itself does not impart a clear preference for any of the two possible C7 minima. It is the aromatic side chain, which is forced to adopt an almost eclipsed orientation, that breaks this symmetry introducing a marked preference for a single region of the (ϕ, ψ) conformational space in each of the phenylalanine norbornane analogues investigated. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Rydberg electron transitions of the atmospherically important molecule N2O
Authors: Velasco A. M. , Bustos E. , Martín I. , Lavín C. 
Published: August 2002

AbstractTransition intensity data on Rydberg electronic transitions of N2O, which are relevant to atmospheric and astrophysical studies, are reported. The calculations have been performed with the molecular‐adapted quantum defect orbital method, which has proven to be an adequate theoretical tool in the context of Rydberg spectra. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 84: 70–77, 2001