bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parameters affecting the full‐shot molding of gas‐assisted injection‐molded parts
Authors: Liu Shih‐Jung , Chang Kuang‐Huei 
Published: January 2003

AbstractFull‐shot gas‐assisted injection‐molding has the advantage of eliminating the switchover mark that usually occurs on the surface of short‐shot gas‐assisted molded parts. The purpose of this report was to study the effects of processing parameters on the moldability of the full‐shot gas‐assisted injection‐molding process. Experiments were carried out on an 80‐ton injection‐molding machine equipped with a high‐pressure nitrogen‐gas injection unit. The materials used were general‐purpose polystyrene and polypropylene. A plate cavity with a gas channel of various geometries (trapezoid, semicircle, and rectangle) across the center was used to mold the parts. After molding, the lengths of gas penetration were determined. The hollowed core ratio by the gas was also determined. A numerical analysis was carried out to find out the temperature distribution of the polymer melt inside the gas channel. It was found that the sink mark of molded parts decreases with the length of gas penetration. Molded parts using trapezoidal gas channel had the longest gas penetration length. In addition, a thermal contraction model was proposed to predict the gas penetration volume inside the parts. Good agreement was reached between the experimental data and the calculated result. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 1–14, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10036
3‐D modeling reactive molding processes: From tool development to industrial application
Authors: Sekula Robert , Saj Piotr , Nowak Tomasz , Kaczmarek Karol , Forsman Kimmo , Rautiainen Aimo , Grindling Josef 
Published: January 2003

AbstractReactive molding process of thermosetting materials is an area where advanced computer simulations can provide useful information to detect molding problems prior to the mold making. Examples of such problems are premature gelation, undesired weld‐line locations, and air traps. However there is a lack of suitable software that would allow the modeling in a fully three‐dimensional (3‐D) space for such reactive systems. A new approach for the 3‐D simulation of reactive molding process is presented in the paper. In the filling stage fluid dynamics and heat transfer are modeled within a system of resin and a mold, combined with appropriate viscosity and curing reaction models. During the curing phase only heat transfer and curing kinetics are taken into account. The presented approach was verified by comparing computational results for a cylindrical test to experimental measurements and was successfully applied on a real industrial process in manufacturing of a medium voltage combi sensor. The selected results of such simulations are also presented in the paper. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 42–55, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10037
An assessment of the strategies and strengths of medium‐sized food processors
Authors: van Duren Erna , Sparling David , Turvey Calum , Lake Linda 
Published: January 2003

AbstractThis article uses the case method of research to analyze the strategies and strengths of independent, domestically owned, successful medium‐sized processing companies in Canada. The assessment of company strengths is based on responses from open‐ended interviews and a questionnaire. All assessment is based on managers' perceptions, and the theoretical concept of a core competence is used. The key conclusions of the research are (1) there was no single internal factor rated as the number one strength across all managers in any one company, or across all companies, and (2) the factors on which managers rated their companies highest were highly interrelated. Reputation, flexibility and customer service and a set of other management variables interact to produce successful strategies. Being responsive to customer needs requires fast product development in industry niches while close relationships with customers allow the in‐depth understanding of customer needs required for this pace of product development. [EconLit citations: Q130, L200, L660.]. © 2003 Wiley Periodicals, Inc. Agribusiness 19: 115–132, 2003.
Household meat demand in Greece: A demand systems approach using microdata
Authors: Lazaridis Panagiotis 
Published: January 2003

AbstractThis article examines meat consumption patterns of households in Greece using data from family budget surveys. For that purpose the linear approximate Almost Ideal Demond System was employed to investigate the economics and demographic effects on the demand for four types of meat. Prices were adjusted for quality, and the demographic translation method was used to incorporate the demographic variables. Finally, the two‐stage generalized Heckman procedure was employed to take into account censoring of the dependent variables. [EconLit citations: Q11, D12.] © 2003 Wiley Periodicals, Inc. Agribusiness 19: 43–59, 2003.
Degree of social contact affects the emission of food calls in the common marmoset (Callithrix jacchus)
Authors: Vitale Augusto , Zanzoni Michela , Queyras Armelle , Chiarotti Flavia 
Published: January 2003

AbstractThe aim of this study was to investigate whether the emission of food calls in common marmosets (Callithrix jacchus) is influenced by different social contexts. Food calls are emitted by this species only in the presence of preferred food. If these calls have any communicative function, it may be that individuals produce food calls in order to call family mates toward the food source. If this is the case, the number of calls produced should vary in accordance with the number of family mates present at the moment of the discovery of the food, i.e., the fewer family mates nearby, the more food calls are emitted. This hypothesis was tested with five pairs of common marmosets, by recording the number of food calls emitted in four experimental conditions: 1) isolation: completely isolated from the family mates; 2) visual isolation: separated by a wooden panel from the family mates; 3) visual contact: separated by a wire‐mesh from the family mates; and 4) physical interaction: together with the family mates. The results show that the proportion of intervals during which food calls were produced by the pairs was significantly different in the four experimental conditions. It decreased from the isolation and visual isolation condition, through the visual contact condition, reaching the lowest value in the physical interaction condition. The variation observed in the proportion of intervals during which food calls were emitted, in relation to different social contexts, is an indication in favor of the communicative function of this vocalization. Am. J. Primatol. 59:21–28, 2003. © 2003 Wiley‐Liss, Inc.
Self‐injurious behavior in rhesus monkeys: New insights into its etiology, physiology, and treatment
Authors: Novak Melinda A. 
Published: January 2003

AbstractSelf‐injurious behavior (SIB) is a significant human health problem frequently associated with profound intellectual disabilities, genetic diseases, and psychiatric conditions. However, it also occurs in subclinical populations and appears to be on the rise in adolescents and young adults. SIB is also seen in a small percentage of nonhuman primates that injure themselves through biting. We have begun to characterize SIB in rhesus monkeys to identify some of the risk factors associated with this disorder, and to determine the parallels with the human condition. In our study population, 14% of individually housed monkeys (the vast majority of which are males) have a veterinary record for self‐inflicted wounding. Wounding is rare, but self‐directed biting is common. SIB can be elicited during aggressive altercations and may be associated with husbandry events. Some monkeys appear to be more vulnerable to acquiring SIB. This increased vulnerability is associated with certain social experiences in the first 2 years of life and with exposure to a larger number of moderately stressful events as compared to controls. Monkeys with SIB also have a dysregulation of the hypothalamic‐pituitary‐adrenal (HPA) axis, indicated by a blunted cortisol response to mild stressors. Our findings suggest that SIB may be a coping strategy to reduce arousal. Biting appears to rapidly lower an escalating heart rate. The potentially reinforcing effects of SIB may account for the failure of some treatment regimens. These findings are compared to studies of SIB in humans, and concordances are identified. Am. J. Primatol. 59:3–19, 2003. © 2003 Wiley‐Liss, Inc.
Long bone articular and diaphyseal structure in Old World monkeys and apes. II: Estimation of body mass
Authors: Ruff Christopher B. 
Published: January 2003

AbstractBody mass estimation equations are generated from long bone cross‐sectional diaphyseal and articular surface dimensions in 176 individuals and 12 species of hominoids and cercopithecoids. A series of comparisons is carried out to determine the best body mass predictors for each of several taxonomic/locomotor groupings. Articular breadths are better predictors than articular surface areas, while cross‐sectional shaft strengths are better predictors than shaft external breadths. Percent standard errors of estimate (%SEEs) and percent prediction errors for most of the better predictors range between 10–20%. Confidence intervals of equations using sex/species means are fairly representative of those calculated using individual data, except for sex/species means equations with very low %SEEs (under about 10%), where confidence intervals (CIs) based on individuals are likely to be larger. Given individual variability, or biological “error,” this may represent a lower limit of precision in estimating individual body masses. In general, it is much more preferable to determine at least broad locomotor affinities, and thus appropriate modern reference groups, before applying body mass estimation equations. However, some structural dimensions are less sensitive to locomotor distinctions than others; for example, proximal tibial articular M‐L breadth is apparently “locomotor blind” regarding body mass estimation within the present study sample. In other cases where locomotor affiliation is uncertain, mean estimates from different reference groups can be used, while for some dimensions no estimation should be attempted. The techniques are illustrated by estimating the body masses of four fossil anthropoid specimens of Proconsul nyanzae, Proconsul heseloni, Morotopithecus bishopi, and Theropithecus oswaldi. Am J Phys Anthropol 120:16–37, 2003. © 2003 Wiley‐Liss, Inc.
Study of crosslinking acid copolymer/DGEBA systems by FTIR
Authors: Cherdoud‐Chihani A. , Mouzali M. , Abadie M. J. M. 
Published: January 2003

AbstractA study of crosslinking of diglycidylether of bisphenol A (DGEBA) by four copolymers of poly(acrylic acid‐co‐styrene) having different acid group percentages, in the range 7.6–76.6%, was done by FTIR. The study was done in the isothermal mode for four different temperatures, the reaction being accelerated by triethylamine. We followed each by temperature and the variation of the area of the epoxy infrared band (912–916 cm−1) versus time. The results showed that the mechanism was complex and depended on the acid composition in the copolymer. Three types of reaction were involved: addition esterification, etherification, and condensation esterification. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2033–2051, 2003
Study on the photo degradation of pulp mold container
Authors: Ou Yifang , Huang Qiulian 
Published: January 2003

AbstractThe photodegradation of a pulp mold container was investigated with ultraviolet light. The results show that the degree of polymerization of samples decreased about 50%, tensile strength decreased 20–30%, sample weight lost 10–16%, and brightness decreased about 20% after 8 weeks of UV irradiation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2052–2056, 2003
Oxidative stabilization of PAN/VGCF composite
Authors: Zhu Dan , Koganemaru Ai , Xu Chunye , Shen Qundong , Li Suolong , Matsuo Masaru 
Published: January 2003

AbstractAn oxidative stabilization process to prepare carbon films was carried out for a new kind of precursor using the composite of polyacrylonitrile (PAN) and vapor‐grown carbon fiber (VGCF) by a process of gelation/crystallization from dilute solutions. It was found that the new precursor has special features in the stabilization process different from those of the homopolymer in regard to thermal and morphological aspects. In the stabilization process under heat treatment at 180–350°C in an oxidative atmosphere, it was inferred that, although the introduction of VGCF hinders the initiation and propagation step of the cyclization and dehydrogenation reactions, the precursor helps the oxidation and the additional aromatization and intermolecular crosslinking reactions in the stabilization process, thus promoting the formation of the later carbon product in film's shape with good performance. From characteristic works by wide‐angle X‐ray diffraction (WAXD), FTIR, Raman, and DSC, the changes of the precursors in structure, morphology, and mechanical property in terms of different heat‐treat temperatures and tensions were studied. Through a series of experimental results, the effect of the VGCF's introduction on those changes was discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2063–2073, 2003
Gel permeation chromatography study of active centers in propylene oxide polymerization catalyzed by C3H5O3K3, C3H5O3K3–CaSO4, C3H5O3K3–crown ether, and C3H5O3K3–CaSO4–crown ether systems
Authors: Huang Mei , Feng Linxian , Hu Gengyuan 
Published: January 2003

AbstractGel permeation chromatography (GPC) is widely used to measure the molecular weights of linear polymers. A detailed analysis of high‐quality GPC data is an important source of information about the kinetics of a polymerization reaction. The living polymerization of epoxide demonstrates that the Poisson function is suitable for a molecular weight distribution description of polyether produced with catalysts containing a single type of active center. Therefore, poly(propylene oxide)s obtained by different catalytic systems, including C3H5O3K3, C3H5O3K3–CaSO4, C3H5O3K3–crown ether, and C3H5O3K3–CaSO4–crown ether, were characterized by GPC. The peaks obtained by GPC were resolved with a multi‐Poisson distribution function. This signifies that there might be multiple active sites instead of single site in these catalytic systems. The addition of calcium sulfate to the catalytic systems not only increased the molecular weight of the polyether but also effected the formation of the active sites. Furthermore, the polymerization of propylene oxide was processed in the presence of the aforementioned catalytic systems. Much useful information concerning the kinetic process of the polymerization was obtained from the GPC data with computer analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2100–2105, 2003
Preparation and rheological characterization of intercalated polystyrene/organophilic montmorillonite nanocomposite
Authors: Kim Tae H. , Lim Sung T. , Lee Chung H. , Choi Hyoung J. , Jhon Myung S. 
Published: January 2003

AbstractPolystyrene (PS)/organophilic montmorillonite (OMMT) clay nanocomposites were prepared by a solvent casting method using chloroform as a cosolvent. Intercalation of the OMMT in the PS matrix was achieved as revealed by X‐ray diffraction. The IR spectra of the products indicated that the OMMT is homogeneously dispersed in the PS matrix. A thermogravimetric analysis (TGA) showed that the onset temperature increases linearly with the clay content. The glass‐transition temperature of the PS, examined using differential scanning calorimetry, had a trend similar to that from the TGA. The rheological properties of the PS/OMMT nanocomposites were also investigated via a rotational rheometer with a parallel plate geometry, and they exhibited sharper shear thinning and increased storage and loss modulus with clay content. Furthermore, the shear viscosity obtained from the steady shear experiment was well correlated with the complex viscosity obtained from the oscillatory experiment via the Cox and Merz relation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2106–2112, 2003
Synthesis and characterization of poly(dimethylsiloxane)–polythiophene composites
Authors: Sankır Mehmet , Küçükyavuz Zuhal , Küçükyavuz Savaş 
Published: January 2003

AbstractThe synthesis was performed by the electropolymerization of thiophene on a poly(dimethylsiloxane) (PDMS)‐coated platinum electrode at 2.2 V with tetrabutylammoniumtetrafloroborate (TBAFB) as a supporting electrolyte and with acetonitrile as a solvent. The characterization of the PDMS–polythiophene (Pth) composites was carried out with cyclic voltammetry, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis, and conductivity measurements. The observed conductivities of the PDMS composites were 2.2–5.2 S/cm. The conductivity of Pth did not change appreciably with the addition of up to 30% insulating PDMS, but its processability improved. FTIR, SEM, and DSC studies showed the existence of a strong interaction, rather than physical adhesion, between PDMS and Pth. Highly flexible and foldable PDMS–Pth composites were obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2113–2119, 2003
A comparison of Newtonian and viscoelastic constitutive models for dry spinning of polymer fibers
Authors: Gou Zeming , McHugh Anthony J. 
Published: January 2003

AbstractA comparison is made of the predictions of one‐dimensional mathematical model simulations of dry spinning based on Newtonian and viscoelastic constitutive equations for the spin dope. The viscoelastic model is based upon a modified Giesekus constitutive equation with a temperature and composition‐dependent relaxation time. The simulation algorithm includes the effects of the glass transition on the expected solution viscosity and relaxation time behavior along the spinline. Predictions of axial velocity, tensile stress, and composition profiles for the two cases suggest the role of viscoelasticity in the locking‐in behavior associated with fiber solidification along the spinline. The effects of model parameters and processing conditions are also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2136–2145, 2003
Determination of green‐bond strength in tacky poly(vinyl alcohol) hydrogels
Authors: Ben‐Zion Omri , Karpasas Mark , Nussinovitch Amos 
Published: January 2003

AbstractPressure‐sensitive tack is the adhesive property related to bond formation. It is a key issue when formulating hydrogel poultices for transdermal delivery, dressings, and bioelectrodes. Quantitative tack gives an indication of the potential ease and success of application when gels are brought into contact with skin. The effects of different dwell times and constant pressures on bond formation between tacky poly(vinyl alcohol) (PVA) hydrogels and a skin model were explored in the current study; these were correlated with viscoelastic properties in order to elucidate structure–function relationships. A rolling tack test was performed using a novel apparatus capable of simultaneously controlling the pressure and dwell time in a hydrogel/skin‐model‐probe system. PVA gels were formed via the freeze–thaw technique using Ca2+ ions. Lower calcium availability in PVA gels resulted in longer dwell times required to complete bond formation, decreased creep compliance (at 0.01 s) and a decreased G′(ω = 40)/G′(ω = 0.01) ratio, all three leading to a loss in tack strength. All tested gels were found to have pressure‐sensitive tack. The results of this study support the applicability of a rheological methodology and a novel tack‐testing procedure to quantify green‐bond formation in pressure‐sensitive‐adhesive PVA hydrogels. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2130–2135, 2003
Determination of moisture content in nylon 6,6 by near‐infrared spectroscopy and chemometrics
Authors: Camacho Walker , Vallés‐Lluch Ana , Ribes‐Greus Amparo , Karlsson Sigbritt 
Published: January 2003

AbstractThe effects of moisture on the morphology and mechanical properties of polyamides have been extensively studied by a number of researchers. However, the assessment of water content in the resins has been carried out by thermal or thermogravimetric methods, which are destructive. In the present work partial least‐squares (PLS) calibration models based on near‐infrared (NIR) spectroscopy were produced in order to predict the moisture content of nylon 6,6. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and the loss‐on‐drying (LOD) method were used as reference methods. TGA, LOD, DSC, and NIR analysis were performed in parallel, and the obtained data were used for multivariate calibration purposes. Data pretreatment techniques such as derivation and multiplicative scattering correction (MSC) successfully eliminated the baseline offset present in the raw spectra and compensated for differences in thickness and light scattering of the analyzed samples. Calibration models were validated by full cross validation with the help of a test set. A comparison of the prediction ability of PLS models based on pretreated data was also done. NIR spectroscopy is a rapid and nondestructive method for the determination of moisture in recycled nylon. The moisture content can be predicted with a RMSEP = 0.05 wt %. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2165–2170, 2003
Investigation of deformation mechanism in polypropylene/glass fiber composite
Authors: Zebarjad S. M. , Bagheri R. , Seyed Reihani S. M. , Forunchi M. 
Published: January 2003

AbstractA great amount of work has been done over the past few years to understand the structure–properties relationship in polypropylene/glass fiber composites. This is because of the very fast‐growing rate of polypropylene applications in the automotive and other industries. This work focused on the role of glass fibers and fiber–matrix adhesion on deformation mechanism. Composites with different fiber content, with and without adhesion promoter, were fabricated. Tensile tests and microscopy techniques were conducted. Based on the results, a physical model has been proposed that illustrates the initiation and growth of the damage under static loading condition. According to this work, the introduction of glass fibers shifts the deformation mechanism from shear yielding to crazing. Although crazes propagate in a different manner in composites containing standard and treated fibers, no influence of interfacial adhesion was observed on craze thickening phenomenon. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2171–2176, 2003