bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors affecting the work productivity of Oraon agricultural laborers of Jalpaiguri district, West Bengal
Authors: Roy Subrata K. 
Published: October 2004

AbstractIn developing countries like India, where the incidence of protein‐calorie malnutrition is high and mechanization is at a minimum, human labor provides much of the power for physical activity. This study presents anthropometric measurements, somatotypes, food intakes, energy expenditures, and work outputs of Oraon agricultural laborers of the Jalpaiguri district, West Bengal, in an attempt to identify the factors that predict high work productivity. Specifically, this study investigates 1) the relationship between morphological variation (anthropometric measurements and somatotype) and work productivity, 2) the nature and extent of the relationship between nutritional status and work productivity, and 3) the best predictor variables of work output. Classification of groups on the basis of median values of work output show that in the aggregate, the high productive groups are significantly younger than low‐productive groups in both sexes. Before age‐adjustment, the high productive groups show higher mean values of a few body dimensions, though these differ by sex, and both males and females exhibit a normal range of blood pressure and pulse rate values. Mean values of grip strength and back strength are higher in high‐output men and women. Mean values of both food intake and energy expenditure are also higher among men in high‐output groups, with only food intake higher in high‐output women. However, after eliminating the effects of age, the differences between low‐productive groups and high‐productive groups in most of the variables are not significant. Productivity predictors in males consist of age, food intake and chest girth (inhalation). Females, on the other hand, show age and grip strength (left) as work output predictors. Am J Phys Anthropol 117:228–235, 2002. © 2002 Wiley‐Liss, Inc.
Nuclear and mitochondrial genetic variation in the Yanomamö: A test case for ancient DNA studies of prehistoric populations
Authors: Williams Sloan R. , Chagnon Napoleon A. , Spielman Richard S. 
Published: October 2004

AbstractAncient DNA provides a potentially revolutionary way to study biological relationships in prehistoric populations, but genetic patterns are complex and require careful interpretation based on robust, well‐tested models. In this study, nuclear and mitochondrial markers were compared in the Yanomamö, to assess how well each data set could differentiate among closely related groups. The villages selected for the study share a recent fission history and are closely related to each other, as would likely be the case among prehistoric peoples living in the same valley or region. The Yanomamö generally practice village‐level endogamy, but some migration and gene flow are known to occur between villages. Nuclear and mitochondrial DNA data were compared using F‐statistics and genetic distance analyses. The nuclear data performed as expected, males and females from the same village were similar, and the villages were genetically distinct, with the magnitude of genetic differences correlated with historical relationship. However, mtDNA analyses did not yield the expected results. The genetic distances between villages did not correlate with historical relationship, and the sexes were significantly different from each other in two villages. Both the Lane and Sublett and the Spence methods, used to test for archaeological residence patterns, were consistent with endogamy. Hence, ancient DNA can, in principle, provide us with a unique opportunity to study genetic structure and gene flow in archaeological populations. However, interpretations, particularly those based on single loci such as mitochondrial DNA, should be cautious because sex‐specific migration and sampling issues may have dramatic effects. Am J Phys Anthropol 117:246–259, 2002. © 2002 Wiley‐Liss, Inc.
Technical note: CT‐guided biopsy: A new diagnostic method for paleopathological research
Authors: Rühli Frank J. , Hodler Jürg , Böni Thomas 
Published: October 2004

AbstractThe aim of this paper was to demonstrate the application of computerized tomographic (CT)‐guided biopsy in a paleopathological examination. Researchers dealing with such special tasks should be aware of this method. We performed a CT‐guided percutaneous biopsy of an ancient Egyptian child mummy, which allowed us to revise its initial diagnosis.Based on this experience, extended preinterventional planning and the choice of equipment (needle type) preferred by performing radiologists are strongly recom‐ mended, since they will influence diagnostic outcome. Easy documentation, suitable approaches according to the object's condition, and a reliable anatomical orientation without superposition effects during the procedure are some of the advantages of this method. It its already widely established in clinical practice. This technique is recommended for future tissue‐sampling of human paleopathologic remains like mummies that are still wrapped within their original bandages, or any small bone lesion of unclear etiology. Am J Phys Anthropol 117:272–275, 2002. © 2002 Wiley‐Liss, Inc.
Studies on the interaction of DNA and water‐soluble polymeric Schiff base–nickel complexes
Authors: Xiao Yao‐Nan , Zhan Chun‐Xia 
Published: October 2004

AbstractThe modes and activities of the interaction of DNA and water‐soluble polymeric Schiff base–nickel complexes, which have been prepared by polymeric analogous reaction, have been discussed according to absorption spectra, circular dichroism spectra, and fluorescent probe method. It is indicated that polymeric matrix effect and increasing solubility in water can increase the interaction of these water‐soluble polymeric metal complexes with DNA. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 887–893, 2002; DOI 10.1002/app.10000
Hydrolytic degradation and diffusion studies on a polyphosphate ester
Authors: Narendran N. , Kishore K. 
Published: October 2004

AbstractA polyphosphate ester was synthesized by interfacial polycondensation of bisphenol‐A and phenylphosphorodichloridate. Accelerated hydrolytic degradation studies were conducted under alkaline conditions. The effect of concentration of alkali and temperature were monitored. The rate of degradation reached a maximum value at 6 molar sodium hydroxide solution and then reduced. The activation energy for hydrolytic degradation was found to be 45 kcal/mol. Diffusion of alkali into the polymer pellet was studied at various concentrations of alkali and at various temperatures. The rate of diffusion also attained a maximum at 6M NaOH and the activation energy for diffusion process was found to be 12 kcal/mol. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 701–708, 2002; DOI 10.1002/app.10008
Resol‐type phenolic resin from liquefied phenolated wood and its application to phenolic foam
Authors: Lee Seung‐Hwan , Teramoto Yoshikuni , Shiraishi Nobuo 
Published: October 2004

AbstractA liquefied wood‐based resol resin was prepared with excellent yield by a reaction of liquefied wood and formaldehyde under alkaline conditions. The effects of various reaction parameters on the extent of the yield of the resol resin, unreacted phenol content, and viscosity were investigated. Milder resol resinification conditions were required as compared to those used in conventional methods. The liquefied wood‐based resol resin was successfully applied to produce phenolic foam using appropriate combinations of foaming agents. Diisopropyl ether with a relatively higher boiling temperature was suitable for the foaming of liquefied wood‐based resol resin. Hydrochloric acid and poly(ethylene ether) of sorbitan monopalmitate were used as a catalyst and a surfactant, respectively. The obtained foams showed satisfactory densities and compressive properties, comparable to those of foams obtained from conventional resol resin. Foams with low density were obtained by the blending of liquefied wood‐based resol resin and conventional resol resin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 468–472, 2002; DOI 10.1002/app.10018
Preparation, morphology, and thermoelectric property studies of BaTiO3 superfine fiber/castor oil polyurethane‐based IPN nanocomposites
Authors: Dongyan Tang , Liangsheng Qiang , Zheng Jin , Weimin Cai 
Published: October 2004

AbstractA series of castor oil polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (IPNs) and gradient IPNs, cured at room temperature, were prepared by a simultaneous IPN method. The polymerization processes were traced through IR techniques; results for the morphology and miscibility among multiple phases of materials, obtained by transmission electron microscopy, indicated that the systems belonged to graft‐mode IPNs, and the domains between two phases were controlled on a nanometer scale. Thermomechanical analysis detection results showed that through interpenetration between networks, the glass‐transition temperatures of the systems could be linked up effectively. Furthermore, the systems were combined with selected barium titanate superfine fibers. The composite techniques were determined, and the thermoelectric and mechanical properties were examined in detail. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 709–715, 2002; DOI 10.1002/app.10024
Acid‐catalyzed liquefaction of waste paper in the presence of phenol and its application to Novolak‐type phenolic resin
Authors: Lee Seung‐Hwan , Teramoto Yoshikuni , Shiraishi Nobuo 
Published: October 2004

AbstractLiquefaction of waste paper (WP) was performed in the presence of phenol with an acid catalyst. Newspaper (NP) was liquefied more easily than box paper (BP) or business paper (BNP). Differences in the degree of liquefaction were due to different chemical compositions. That is, NP had a relatively high lignin content, which is known to be easily liquefied, whereas BP and BNP were mainly composed of cellulose with a crystalline structure, which is difficult to liquefy. The acid concentration and phenol/WP ratio were more important factors in the regulation of liquefaction than reaction temperature. The changes in the apparent molecular weight depending on the reaction time were more significant for phenolated NP, with high lignin content, than for phenolated BP. The obtained phenolated products showed thermal flow properties and reactivity as good as those of phenolated wood and commercial Novolak resin. Thermosetting moldings were obtained from phenolated products, and their flexural properties and thermal stability were comparable to those of phenolated wood and commercial Novolak resin. Flexural properties were further improved by the cocondensation reaction between the unreacted phenol of phenolated products and formaldehyde. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1473–1481, 2002
Biodegradable polyurethane foam from liquefied waste paper and its thermal stability, biodegradability, and genotoxicity
Authors: Lee Seung‐Hwan , Teramoto Yoshikuni , Shiraishi Nobuo 
Published: October 2004

AbstractLiquefaction of waste paper (WP) was conducted in the presence of polyhydric alcohols to prepare biodegradable polyurethane foam. The liquefied‐WP‐based polyol had suitable characteristics such as apparent molecular weight, hydroxyl value, and viscosity for the preparation of rigid polyurethane foam and was successfully applied to produce polyurethane foam with the appropriate combinations of foaming agents. The obtained foams showed satisfactory densities and mechanical properties as good as those of foams obtained from liquefied wood‐ and starch‐based polyols. The foams had almost the same thermal stability at initial weight loss and seemed to be potentially biodegradable because they were degraded to some extent in leaf mold. There were no mutagens or carcinogens in the water extracts of the foams. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1482–1489, 2002
Retention properties of efficient adsorbent to silver(I)
Authors: Rivas Bernabé L. , Pooley S. Amalia , Ruf Beatriz , Reyes Patricio , Cárdenas Galo 
Published: October 2004

AbstractThe binding capability of crosslinked poly(acrylic acid‐co‐2‐acrylamide‐2‐methyl‐1‐propane sulfonic acid) for silver(I) ions by the batch equilibrium method is investigated. The effects of the pH, temperature, time of contact, and resin–metal ion molar ratio on the retention ability are studied. The retention for silver(I) increases from 21.7% at pH 1 to 94.6% at pH 5. The adsorption capacity at pH 5 is 1.18 meq/g dry resin. The maximum load capacity at the optimum pH is determined. In order to recover the resin, elution runs in acid and basic media are carried out. The best eluent is 4M HNO3 (84.9%). Moreover, retention–elution cycles are performed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1501–1506, 2002
Dynamic mechanical properties of polycarbonate and acrylonitrile–butadiene–styrene copolymer blends
Authors: Más J. , Vidaurre A. , Meseguer J. M. , Romero F. , Pradas M. Monleón , Ribelles J. L. Gómez , Maspoch M. L. L. , Santana O. O. , Pagés P. , Pérez‐Folch J. 
Published: October 2004

AbstractBlends of polycarbonate (PC) and poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS) with different compositions are characterized by means of dynamic mechanical measurements. The samples show phase separation. The shift in the temperatures of the main dynamic mechanical relaxation shown by the blend with respect to those of the pure components is attributed to the migration of oligomers present in the ABS toward the PC in the melt blending process. A comparison with other techniques (dielectric and calorimetric analysis) and the application of the Takayanagi three block model confirm this hypothesis. In all the studied blend compositions (ABS weight up to 28.6%) the PC appears as the matrix where a disperse phase of ABS is present. The scanning and transmission electron microscopy micrographs show that the size of the ABS particles increases when the proportion of ABS in the blend increases. The FTIR results indicate that the interaction between both components are nonpolar in nature and can be enhanced by the preparation procedure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1507–1516, 2002
Thermogravimetric study of degradation process of diglycidyl ether of bisphenol A–1,2‐diaminocyclohexane/calcium carbonate system
Authors: Núñez Lisardo , Castro A. , Villanueva M. , Núñez M. R. , Rial B. 
Published: October 2004

AbstractThe thermal degradation of the epoxy system consisting of diglycidyl ether of bisphenol A (BADGE, n = 0)–1,2‐diaminocyclohexane (DCH) containing calcium carbonate filler is studied by thermogravimetric analysis to determine the reaction mechanism of the degradation process. The value of the activation energy, which is necessary for this study, is calculated using various integral and differential methods. The values obtained using the different methods are compared to the value obtained by Kissinger's method (234.84 ± 15.12 kJ/mol), which does not require knowledge of the n‐order value of the reaction mechanism. All the experimental results are compared to master curves in the range of Doyle's approximation (5–35% of conversion). The analysis of the results suggests that the reaction mechanism is a sigmoidal A2 type. The thermodegradation mechanism is similar to that found for the same epoxy system without additives. However, for this last system the sigmoidal mechanism is an A4 type. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1528–1535, 2002
Effect of phenol derivatives on molecular dimensions of poly(N‐vinyl‐2‐pyrrolidone) in aqueous solution
Authors: Kirci Betül , Güner Ali 
Published: October 2004

AbstractThe unperturbed dimensions and thermodynamic parameters of poly(N‐vinyl‐2‐pyrrolidone) (PVP) were studied in aqueous solutions in the presence of certain phenolic cosolutes (phenol, catechol, hydroquinone, resorcinol, and phloroglucinol). The intrinsic viscosities at 25°C and the θ temperature, linear and thermodynamic expansions, and root mean square end to end distances were evaluated for the system that was employed. The sequence was obtained due to the effectiveness of the cosolutes in the order of phloroglucinol > resorcinol > hydroquinone > catechol > phenol. The effects of these cosolutes on the main thermodynamic parameters were reported to be due to the number and position of hydroxyl groups present. The thermodynamic interaction parameter was also evaluated and the enthalpic and entropic contributions were verified. The condition required for the θ temperature to correspond to a Flory interaction parameter of 0.5 was well provided, yielding a θ temperature of almost 0.5 for the system under study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 473–477, 2002; DOI 10.1002/app.10047
Synthesis and characterization of novel aromatic ether nitrile monomer containing propenylphenoxy groups and properties of its copolymer with 4,4′‐bismaleimidodiphenylmethane
Authors: Fang Qiang , Ding Xuemei , Wu Xiongying , Yue Yi , Jiang Luxia 
Published: October 2004

AbstractA novel aromatic ether nitrile monomer containing propenyl groups, 2,6‐di{2‐[(E)‐1‐propenyl]phenoxy} benzonitrile (DPPB), was synthesized by the reaction of 2,6‐dichlorobenzonitrile and 2‐allylphenol using anhydrous potassium carbonate as the acid acceptor, N‐methyl pyrrolidone as the dipolar aprotic solvent, and toluene as the dehydrating agent. The chemical structure of DPPB was characterized by FTIR and 1H‐NMR. The monomer was used to modify a popular commercial bismaleimide, 4,4‐bismaleimidodiphenylmethane (BMDPM), to improve the shear strength of the resin. The results showed that DPPB could effectively improve the shear strength of the BMDPM resin without decreasing the heat resistance of BMDPM. A better result was obtained when the composition of DPPB in the copolymer was 45 wt %. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1465–1472, 2002
Toughening and reinforcing in rigid inorganic particulate filled poly(propylene): A review
Authors: Liang Ji‐Zhao 
Published: October 2004

AbstractThe recent advances in the toughening and reinforcing methods and theories in rigid inorganic particulate (RIP)‐filled poly(propylene) (PP) composites have been reviewed. Studies have shown that under given conditions, in addition to the obvious increase of modulus, an obvious brittle–ductile transition also appears in these composites. The key to toughening a polymer is the role that inclusions can play as agents that (1) induce extensive plastic deformation following the interfacial debonding between the inclusion itself and the matrix, (2) induce shear yielding of the matrix, and (3) terminate the propagation of cracks. The main factors with regard to reinforcing mechanisms are how to enhance the interfacial bonding between the particles and the matrix and how to improve the dispersion of inclusions in the matrix. The major theories interpreting the toughening mechanisms of polymer–RIP composites include micro‐voiding theory, damage competition theory, shear yielding theory, etc. It is necessary to form a soft shell/hard core structure to simultaneously toughen and reinforce polymers. Therefore, RIPs should be encapsulated with an elastic thin layer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1547–1555, 2002
Synthesis and characterization of the epoxyfumarate resins
Authors: Matynia T. , Księżopolski J. , Gawdzik B. 
Published: October 2004

AbstractThe synthesis and properties of the new epoxyfumarate and epoxymaleate resins obtained by the addition of acidic allyl maleate to the commercially available resin Epidian 5 are presented. The resins were synthesized in one‐ and two‐step procedures and properties of the obtained resins are compared. It should be noted that the use of allyl alcohol in the synthesis of unsaturated resins has an advantageous influence on their properties. Glass‐transition temperatures of the epoxyfumarate resins exceed 100°C, whereas those of epoxymaleates are higher than 70°C. The resins are also characterized by good chemical resistance. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 716–722, 2002; DOI 10.1002/app.10067
Electroinduced dispersion polymerization of acrylonitrile in the presence of poly(acrylic acid) and catalytic amount of CE(IV)
Authors: Saraç A. S. , Ustamehmetoglu B. , Yildirim H. 
Published: October 2004

AbstractElectroinduced dispersion polymerization of acrylonitrile initiated by Ce(IV) was performed in an electrolytic cell in the presence of poly(acrylic acid) (PAA). Micron‐size polyacrylonitrile (PAN) particles were stabilized with PAA by electrostatic interaction or by a PAA–Ce(III)–PAN ternary complex formation. A PAA–PAN stable polymer was formed in the cathodic compartment, and the reduced initiator was reoxidized in the anode, thus allowing for the continuation of the process. A possible mechanism of polymerization is suggested. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 723–728, 2002; DOI 10.1002/app.10076
Plasma‐induced copolymerization of hydrochloride of N,N‐dimethylaminoethyl methacrylate and acrylamide
Authors: Lu Jianmei , Cheng Zhenping , Zhu Xiulin , Zhang Lifen 
Published: October 2004

AbstractA super alcohol‐absorbing resin, with absorbency of 106 g/g for methanol, was polymerized from the hydrochloride of N,N‐dimethylaminoethyl methacrylate (DM) and acrylamide (AM) by plasma‐induced polymerization at lower temperatures in water solutions. Many factors affecting the absorbing properties, such as post‐polymerization time, monomer concentration, plasma duration, plasma discharge power, monomer ratio, et al., were studied. The reasons for the absorbing alcohol of resins was also discussed. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 729–734, 2002; DOI 10.1002/app.10086
Ionic conductivity and interfacial properties of polymer electrolytes based on PEO and boroxine ring polymer
Authors: Yang Yunsong , Inoue T. , Fujinami T. , Mehta M. A. 
Published: October 2004

AbstractBlended polymer electrolytes based on poly(ethylene oxide) (PEO) and boroxine ring polymer (BP) solvated with lithium triflate were formulated and evaluated. Compared to PEO–salt polymer electrolyte, ionic conductivities of blended polymer electrolytes were two orders of magnitude higher in a low‐temperature range; as well, lithium transference numbers were increased to ∼ 0.4. These were due to the increased mobility and anion trapping of boroxine rings. BP also exhibited the stabilizing effect on lithium–polymer electrolyte interface, and a reduced interfacial resistance between lithium metal and the polymer electrolyte was found with increasing of BP content. Polymer electrolytes based on PEO and BP are suitable for use in lithium secondary battery. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 17–21, 2002; DOI 10.1002/app.10090
A comprehensive model for solid‐state polycondensation of poly(ethylene terephthalate): Combining kinetics with crystallization and diffusion of acetaldehyde
Authors: Wang Xia‐Qin , Deng De‐Chun 
Published: October 2004

AbstractA comprehensive mathematical model was established by considering the main and side reactions for solid‐state polycondensation of poly(ethylene terephthalate). The effect of temperature on chain mobility was used to estimate the rate constants of chemical reactions. The polymer crystalline fraction was modeled as containing only repeat units, thus concentrating end groups and condensates in the amorphous fraction. The diffusion coefficient of acetaldehyde was calculated by the model. The simulation results of this comprehensive model were validated by experimental data reported in literature. The model predictions were important clues for further experimental study on poly(ethylene terephthalate) solid‐state polycondensation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3133–3144, 2002; DOI 10.1002/app.10113