bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermoplastic polymers as modifiers for urea‐formaldehyde (UF) wood adhesives. II. Procedures for the preparation and characterization of thermoplastic‐modified UF wood composites
Authors: Rachtanapun P. , Heiden P. 
Published: December 2002

AbstractWood composites were prepared by using wood flour (sugar maple, Acer saccharum March) and thermoplastic‐modified urea‐formaldehyde (UF) suspensions. Thermoplastic (5–10% w/v) was introduced into the UF suspension as an aqueous solution, a self‐stabilized dispersion in water, or as a surfactant‐stabilized latex. The modified suspension was blended with wood flour, and the blend was cured by using a cure cycle that was suitable for all the thermoplastic‐modified UF formulations and unmodified UF controls. The wood flour composites were tested by using a notched Izod impact strength test. All formulations containing surfactant decreased the impact strength by ∼ 30–40% relative to the unmodified UF control, whereas the water‐soluble thermoplastic had no effect on the impact strength. The formulations with self‐dispersed thermoplastics all increased the notched Izod impact strength, with the greatest increase being 69% more than the UF control, except in a single instance when the molecular weight of the thermoplastic was very high, which decreased resin flow. Increasing the thermoplastic content from 5 to 10% w/v did not further improve the impact test results. Scanning electron microscopy of the fracture surfaces showed morphological differences in the systems that varied with the thermoplastic and method of thermoplastic addition to the UF suspension.© 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 898–907, 2003
Study on preparation of heterogeneous polysulfone affinity filter membrane and its sorption properties for Hg2+
Authors: Wang Bing , Cui Yongfang , Du Qiyun , Pei Guangling 
Published: December 2002

AbstractHigh quality heterogeneous polysulfone affinity flat filter membranes having chelating groups were prepared by phase separation by the use of blends of chelating resin and polysulfone as membrane materials, N,N‐dimethylacetamide as the solvent, and water as the extraction solvent. The effects of blending ratio, chelating resin grain size, and temperature of casting solution on the structure of affinity membranes were investigated. The sorption process of an affinity filter membrane for Hg2+, adsorbed under various chelating conditions such as chelating resin grain size, pH value, and the concentration of the metallic ion solution, was also studied. The results revealed that the greatest chelating capacity of an affinity filter membrane for Hg2+ was 1050 μg/cm2 per membrane under appropriate conditions, and the sorption isotherms of Hg2+could be expressed by the Freundlich sorption model. Dynamic chelating experiments indicated that the Hg2+ could be extracted with the affinity filter membrane and reextracted under acidic conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 908–915, 2003
Surface modification of jute yarn by photografting of low‐glass transition temperature monomers
Authors: Sawpan Moyeenuddin A. , Khan Mubarak A. , Abedin M. Z. 
Published: December 2002

AbstractJute yarns were grafted with three types of vinyl monomers of different functionalities such as methyl acrylate (MA), ethyl acrylate (EA), and 2‐hydroxyethyl acrylate (HEA) with ultraviolet radiation. The graft copolymerization reaction between the cellulose of the jute fibers and the monomer and the chemical environment of the treated fibers were confirmed by Fourier transform infrared spectroscopy. The reduction of OH groups and increment of >CO groups in treated jute yarns were observed. DSC studies showed that the treated jute fibers were more thermally stable compared to the untreated one. The surface topography of the yarns was analyzed by an environmental scanning electron microscope. Different parameters, such as concentration of monomers and irradiation time, were optimized with the extent of mechanical properties such as tensile strength and elongation at break of the jute yarn. MA, EA, and HEA produced enhanced tensile strengths of 87, 78, and 85%, respectively. The monomers MA, EA, and HEA showed improved elongations at break of 118, 91, and 76%, respectively. The water uptake of treated and untreated jute yarns were studied. The maximum water uptake was observed of the grafted sample compared to the untreated jute yarn. The effects of additives such as urea on mechanical properties were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 993–1000, 2003
Rice husk ash filled natural rubber. I. Overall rate constant determination for the vulcanization process from rheometric data
Authors: da Costa H. M. , Visconte L. L. Y. , Nunes R. C. R. , Furtado C. R. G. 
Published: December 2002

AbstractBlack rice husk ash (BRHA) and white rice husk ash (WRHA) were incorporated into natural rubber (NR) using a laboratory‐size two‐roll mill. A conventional vulcanization system (CV) was chosen and cure studies were carried out on a TI‐100 Curometer. The torque curves were obtained at 150, 160, 170, and 180°C. The overall rate and the apparent activation energy for the vulcanization process were calculated for each compound assuming that vulcanization follows first‐order kinetics. For comparison purposes, two commercial fillers, precipitated silica (Zeosil‐175) and carbon black (N762), were also used. It was observed that addition of WRHA to NR compounds increased the cross‐linking rate and lowered the apparent activation energy more markedly than the other fillers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1194–1203, 2003
Filled elastomers: Mid‐ and near‐IR spectroscopic determination of rubber dimensions in composite in unstretched state and under uniaxial extension
Authors: Bokobza Liliane , Rapoport Olivier 
Published: December 2002

AbstractA Fourier transform IR investigation of reinforced elastomers is presented. The work is essentially carried out in the near‐IR range, that allows the analysis of thick samples. The dependence of the average rubber phase dimensions on the filler loading is analyzed. The matrix chain deformation processes can be evaluated by looking at the strain dependence of the intensity of specific absorption bands of the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1204–1208, 2003
Preparation of magnetic poly(vinyl alcohol) (PVA) materials by in situ synthesis of magnetite in a PVA matrix
Authors: Lin Hai , Watanabe Yoshimi , Kimura Mutsumi , Hanabusa Kenji , Shirai Hirofusa 
Published: December 2002

AbstractAn easy method for manufacturing homogeneous inorganic–organic materials, especially composite fibers, was obtained by the in situ synthesis of inorganic particles within polymer matrices. In this article, nanosized magnetite particles were synthesized in situ within poly(vinyl alcohol) (PVA) solutions by precipitating Fe2+ ions or a mixture of Fe2+ and Fe3+ ions with NaOH solution. As a result, magnetite particles with an average diameter of 20 nm were obtained homogeneously within the solutions because of the tridimensional structure and chelating capacities of PVA. Transparent films were obtained by a casting method, and six kinds of magnetic PVA fibers were also prepared by a wet‐spinning method from the solutions containing magnetite nanoparticles. The mechanical properties and the saturation magnetization of the fibers were measured. These fibers, which contain iron ions with a maximum content of 17.63 wt %, can be successfully fabricated by the in situ synthesis and they exhibit excellent magnetization properties (i.e., the largest saturation magnetization is 13.38 emu/g). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1239–1247, 2003
Synthesis and characterization of self‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) nanotubes
Authors: Wei Zhixiang , Wan Meixiang 
Published: December 2002

AbstractSelf‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) (PANI‐ANSA) was synthesized by the copolymerization of 5‐aminonaphthalene‐2‐sulfonic acid (ANSA) and aniline. Scanning electron microscopy and transmission electron microscopy showed that the morphology of PANI‐ANSA synthesized at a high molar ratio of aniline to ANSA was nanotubular, but at a low molar ratio, only a granular morphology formed. A possible formation mechanism for nanotubes was proposed. PANI‐ANSA had better thermal stability than HCl‐doped polyaniline; the highest onset decomposition temperature was as high as 340°C because of SO3H linked with the polymer backbone by a covalent bond. PANI‐ANSA was partially soluble in basic solutions, and its conductivity was between 10−2 and 10−4 S/cm, depending on the sulfonation degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1297–1301, 2003
Poly(ethylene‐co‐methacrylic acid)–lithium ionomer as a compatibilizer for poly(ethylene terephthalate)/linear low‐density polyethylene blends
Authors: Retolaza A. , Eguiazábal J. I. , Nazábal J. 
Published: December 2002

AbstractPoly(ethylene terephthalate) (PET)/linear low‐density polyethylene (LLDPE) blends (75/25), with contents of poly(ethylene‐co‐methacrylic acid) partially neutralized with lithium (PEMA–Li) that were systematically changed from 0 to 45% relative to the LLDPE, were obtained by direct injection molding in an attempt to (1) ameliorate the performance of the binary blend and (2) find the best compatibilizer content. PEMA–Li did not modify the PET or LLDPE amorphous‐phase compositions or the crystalline content of PET. However, PEMA–Li did lead to a nucleation effect and to the presence of a second smaller and less perfect crystalline structure. PET induced a fractional crystallization in LLDPE that remained in the presence of PEMA–Li and reduced the crystallinity of LLDPE. The ternary blends showed two similar dispersed LLDPE and PEMA–Li phases with small subparticles, probably PET, inside. The compatibilizing effect of PEMA–Li was clearly shown by the impressive increase in the break strain, along with only small decreases in the modulus of elasticity and in the tensile strength. With respect to the recycling possibilities of LLDPE, a ternary blend with the addition of 22.5% PEMA–Li, which led to very slight modulus and yield stress decreases with respect to the binary blend and a break strain increase of 480%, appeared to be the most attractive. However, the highest property improvement appeared with the addition of 37.5% PEMA–Li, which led to elasticity modulus and tensile strength decreases of only 9%, along with a very high break strain increase (760%). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1322–1328, 2003
Effect of polymer concentration on polarization switching in polysiloxane‐dispersed ferroelectric liquid crystals
Authors: Sumana G. , Raina K. K. 
Published: December 2002

AbstractFerroelectric liquid crystal–polysiloxane composite films were prepared after dissolving them in diethyl ether as a solvent. The crosslinking was done by adding room temperature vulcanizer (mixture of tetra ethoxy silane and dibutyl tin dilaurate) as curing agent. These composite films show good electro‐optic properties with switching times on the order of few milliseconds. The preliminary results show that these systems can be useful as functional materials in electronic displays. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1209–1215, 2003
An Empirical Comparison of Parametric and Semiparametric Cure Models
Authors: Peng Yingwei , Carriere K.C. 
Published: December 2002

AbstractParametric and semiparametric cure models have been proposed for cure proportion estimation in cancer clinical research. In this paper, several parametric and semiparametric models are compared, and their estimation methods are discussed within the framework of the EM algorithm. We show that the semiparametric PH cure model can achieve efficiency levels similar to those of parametric cure models, provided that the failure time distribution is well specified and uncured patients have an increasing hazard rate. Therefore the semiparametric model is a viable alternative to parametric cure models. When the hazard rate of uncured patients is rapidly decreasing, the estimates from the semiparametric cure model tend to have large variations and biases. However, all other models also tend to have large variations and biases in this case.
The Utilization of Kurtosis in the Estimation of the Parameters of the One‐Way Random Effects Model
Authors: Singh Housila P. , Shukla Sushil K. , Singh Sarjinder 
Published: December 2002

AbstractThis paper deals with the problem of estimating the components of the variance of one‐way random effects model under non‐normality situation using a prior knowledge of coefficient of kurtosis. We have suggested two classes of estimators $\hat \sigma _{(p)}^2 $ and $\hat \sigma _{(q)}^2 $ for the within and between variances respectively. Optimum estimators in the classes of $\hat \sigma _{(p)}^2 $ and $\hat \sigma _{(q)}^2 $ are identified with their mean squared errors formulae and compared with that of usual ANOVA unbiased and Shoukri, Tracy and Mian's (1990) estimators. It is found that the proposed estimators are more efficient than the ANOVA unbiased estimators and Shoukri, Tracy and Mian (1990) estimators.
Validation of Surrogate Endpoints in Multiple Randomized Clinical Trials with Discrete Outcomes
Authors: Renard Didier , Geys Helena , Molenberghs Geert , Burzykowski Tomasz , Buyse Marc 
Published: December 2002

AbstractThis article extends the work of Buyse et al. (2000) on the validation of surrogate endpoints in a meta‐analytic setting to the case of two discrete outcomes, the focus being on binary endpoints. The methodology entails fitting of a joint model for the surrogate and the true endpoints that includes several random effects. We propose to fit this model using a pairwise likelihood (PL) approach which seems better suited to the problem at hand than maximum likelihood or penalized quasi‐likelihood. The performance of the PL estimator is evaluated on the grounds of limited simulations and the methodology is illustrated on data from a meta‐analysis of five clinical trials comparing antipsychotic agents for the treatment of chronic schizophrenia.
Estimation of Spatial Variation in Risk Using Matched Case‐control Data
Authors: Jarner Mikala F. , Diggle Peter , Chetwynd Amanda G. 
Published: December 2002

AbstractA common problem in environmental epidemiology is to estimate spatial variation in disease risk after accounting for known risk factors. In this paper we consider this problem in the context of matched case‐control studies. We extend the generalised additive model approach of Kelsall and Diggle (1998) to studies in which each case has been individually matched to a set of controls. We discuss a method for fitting this model to data, apply the method to a matched study on perinatal death in the North West Thames region of England and explain why, if spatial variation is of particular scientific interest, matching is undesirable.
Estimation of Poisson Rates with Misclassified Counts
Authors: Bratcher Thomas L. , Stamey James D. 
Published: December 2002

AbstractThe Poisson assumption is popular when data arises in the form of counts. In many applications such counts are fallible. Little research has been done on the Poisson distribution when both false positives and false negatives are present. We present a model in this paper that corrects for misclassification of count data. Bayesian estimators are developed. We provide the actual posterior distributions via integration. Markov Chain Monte Carlo results, which are more convenient for large sample sizes, are utilized for inference.
Effect of phosphonate additive on crystallization of gypsum in phosphoric and sulfuric acid medium
Authors: El‐Shall H. , Rashad M.M. , Abdel‐Aal E.A. 
Published: December 2002

AbstractUnderstanding the mechanisms of growth and inhibition during crystallization of calcium sulfate is of primary importance for many industrial applications. For instance, inhibition of the crystallization process may be required to prevent scale formation in pipes, boilers, heat exchangers, reactors, reverse osmosis membrane surfaces, cooling water systems, secondary oil recovery utilizing water flooding techniques and desalination evaporators, etc. On the other hand, control growth and morphology of gypsum crystals is desired in achieving higher filtration rate and higher productivity of phosphoric acid from phosphate rocks. In this regard, this basic study is carried out to understand effect of Aminotris (methylenephosphonic acid (ATMP) on calcium sulfate dihydrate (gypsum) crystallization. The time elapsed between the achievement of supersaturation and the appearance of a solid phase (termed as induction time) is measured under different supersaturation ratios ranging from 1.018 to 1.979. The data are used to calculate the surface energy, critical nucleus size, and crystal growth rates of gypsum under different conditions. The results show that, the induction time decreases exponentially with increasing the supersaturation ratio. In addition, the surface energy decreases with ATMP compared to the baseline (without ATMP). Interestingly, with addition of the ATMP, the crystals mean and median diameters are found to decrease. The inhibition efficiency ranges from 16% to 59% depending on supersaturation ratio.
Crystal growth of some urinary stone constituents: II. In‐vitro crystallization of hippuric acid
Authors: Ramachandran E. , Natarajan S. 
Published: December 2002

AbstractHippuric acid [C6H5CONHCH2COOH], one of the organic chemical constituents of urinary stone is crystallized in silica gel under suitable pH conditions by double diffusion method. The grown crystals were characterized by density measurement, Fourier transform infrared spectroscopy, X‐ray powder diffraction and thermogravimetric analysis.
Influence of thermal annealing on the composition and structural parameters of DC magnetron sputtered titanium dioxide thin films
Authors: Karunagaran B. , Rajendra Kumar R.T. , Mangalaraj D. , Narayandass Sa. K. , Mohan Rao G. 
Published: December 2002

AbstractTitanium dioxide films have been deposited using DC magnetron sputtering technique. Films were deposited onto RCA cleaned p‐silicon substrates at the ambient temperature at an oxygen partial pressure of 7 × 10–5 mbar and sputtering pressure of 1 × 10 –3 mbar. The deposited films were annealed in the temperature range 673–873 K. The structure and composition of the films were confirmed using X‐ray diffraction and Auger electron spectroscopy. The structure of the films deposited at the ambient was found to be amorphous and the films annealed at 673 K and above were crystalline with anatase structure. The lattice constants, grain size, microstrain and the dislocation density of the film are calculated and correlated with annealing temperature.
Crystal structure and properties of [Cu(sac)2(py)3], a new example of a mononuclear complex with both N‐ and O‐bonded saccharinate ligands
Authors: Quinzani O. V. , Tarulli S. H. , Garcia‐Granda S. , Marcos C. , Baran E. J. 
Published: December 2002

AbstractThe crystal structure of the title complex has been determined by single X‐ray diffraction methods and refined to an R‐value of 0.0543. It crystallizes in the monoclinic P21/a space group with a = 21.1231(9), b = 9.4523(4), c = 16.1874(7) Å, β = 107.3706(3)° and Z = 4. The compound represents only the second known example of a simple mononuclear metal complex containing simultaneously N‐ and O‐bonded saccharinato ligands. Its infrared spectrum and thermal behavior are also briefly discussed.
Crystal structure analysis of Bis{(N,N′‐dimethylformamide)‐[μ‐bis‐N,N′‐(2‐oxybenzyl)‐1,3‐propanediaminato](μ‐asetato) nickel(II)}nickel(II)
Authors: Tatar Yildirim L. , Atakol O. 
Published: December 2002

AbstractThe title compound, a homotrinuclear NiII complex has been synthesized from ONNO type Schiff base reduced with the help of NaBH4. The structure of the complex, [Ni{Ni(CH3CO2) (C17H20N2O2) (C3H7NO)}2], was identified using elemental analysis, thermal analysis, IR spectroscopy and x‐ray diffraction techniques. It was established that although some bond lengths and angles changed with respect to previous complexes, the Ni…Ni distance was approximately the same.
Crystal structure of μ‐phenoxo bridged dicopper complex: {N‐[(2‐hydroxylato‐5‐methyl)benzyl‐(2′‐hydroxylato‐3′,5′‐dimethylbenzyl)]ethyl amine dicopper(II)}
Authors: Malathy Sony S. M. , Kuppayee M. , Ponnuswamy M. N. , Manonmani J. , Kandasamy M. , Fun Hoong‐Kun 
Published: December 2002

AbstractThe title compound crystallizes in monoclinic space group C2/c with cell parameters a = 21.404(2), b = 13.962(1), c = 17.917(1)Å, β = 124.394(2)°, V = 4418.3(6)Å3, Z = 8, Dcal = 1.193Mg/m3 and T = 293 K. The structure was solved by Patterson method and refined by full‐matrix least‐squares procedures to final R = 0.0882 using 5253 observed reflections. The tetra coordinated copper atom have a slight distorted square planar geometry with the Cu‐Cu distance of 2.987(1)Å. The two six membered rings containing copper atom assume distorted sofa conformation. C‐H…π and C‐H…O type of intermolecular interactions play a role in stabilizing the crystal packing in addition to van der Waals forces.
Theory of DNA electrophoresis (∼ 1999 –2002 ½)
Authors: Slater Gary W. , Guillouzic Steve , Gauthier Michel G. , Mercier Jean‐François , Kenward Martin , McCormick Laurette C. , Tessier Frédéric 
Published: December 2002

AbstractOver the last two decades, the introduction of new methods such as pulsed‐field gel electrophoresis and capillary array electrophoresis has made it possible to map and sequence entire genomes, including our own. The development of these experimental methods has been helped by the progress of theoretical and computational sciences, and the interactions between these threemodi operandiof modern science are still pushing the limits of our technologies. We now see a clear trend towards proteomics and microfluidic (even nanofluidic!) devices. In this review, we take a look at the progress of the field over the last 3 years using the glasses of the theoretical scientist and focusing mostly on new ideas and concepts. About a dozen different subfields are discussed and reviewed. We conclude by giving a commented list of some of the best review articles published over the last 2–3 years.
Polymeric monolithic stationary phases for capillary electrochromatography
Authors: Hilder Emily F. , Svec Frantisek , Fréchet Jean M. J. 
Published: December 2002

AbstractThis review summarizes the contributions of a number of groups working in the rapidly growing area of monolithic columns for capillary electrochromatography (CEC), with a focus on those prepared from synthetic polymers. Monoliths have quickly become a well‐established stationary phase format in the field of CEC. The simplicity of their in situ preparation method as well as the good control over their porous properties and surface chemistries make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. A wide variety of approaches as well as materials used for the preparation of the monolithic stationary phases are detailed. Their excellent chromatographic performance is demonstrated by numerous separations of different analytes.