bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melt Processability and Foam Suppression of High Molecular Weight Polyethylenes Plasticized with Supercritical Carbon Dioxide
Authors: Wilding M. D. , Baird D. G. , Eberle A. P. R. 
Published: April 2008

Abstract
The purpose of this study is to determine to what extent CO2 can be used as a processing aid to melt process polyethylenes of higher molecular weight than can be typically melt processed. To assess the ability to melt process high molecular weight polyethylenes with CO2, the viscosity of a 460 000 g/mol high density polyethylene (HDPE) plasticized with various amounts of absorbed CO2 in an extrusion process was determined using a slit die rheometer that was attached to the end of the extruder. A relationship was developed to determine the maximum molecular weight polyethylene that could be processed at a given viscosity reduction due to absorbed CO2. This relationship was tested by using CO2 to process a blend of 40 weight percent ultra-high molecular weight polyethylene (UHMWPE) and the 460 000 g/mol HDPE which lead to an equivalent molecular weight of 720 000 g/mol. The viscosity of the blend with 12 weight percent CO2 was reduced to that of the pure 460 000 g/mol HDPE as predicted by the relationship. Preliminary studies using a pressurized chamber attached to the exit of the die allowed one to assess the conditions under which suppression of foaming within fibers or other extruded forms is possible.
Melt Strength and Thermal Properties of Organic Peroxide Modified Virgin and Recycled HDPE
Authors: Parmar H. B. , Gupta R. K. , Bhattacharya S. N. 
Published: April 2008

Abstract
Commercial blow moulding grade recycled high density polyethylene (r-HDPE) and blow moulding grade virgin HDPE were reactively extruded with various compositions (0.00 to 0.15 %) of different peroxides in a twin screw extruder. The aim was to improve the melt strength properties of a blow moulding grade HDPE homopolymer – a polymer resin comprising a significant part of the post consumer recycled plastic stream in Australia. Melting behaviour and crystallinity were investigated by modulated differential scanning calorimetry (MDSC). Uniaxial melt extensional (UME) measurement of the modified materials was carried out using Göttfert Rheotens melt strength tester to measure melt quality of the material. Melt strength and zero shear viscosity were also measured to assess and correlate changes in melt properties due to peroxide modification. Melt strength and zero shear viscosity of both recycled and virgin material were enhanced with the increase in composition of peroxide. However, addition of peroxide also brought with it flow instabilities like draw resonance and necking, both of which lead to limitations in polymer processing.
Mechanical and Thermal Propertiesof Fly Ash/Reclaimed Rubber Powder Composites Improved by KH-550 Coupling Agent
Authors: Wu W.-L. , Chen D.-J. 
Published: April 2008

Abstract
Fly ash (FA) is utilized as a filler to reinforce reclaimed rubber powder (RP) composites by using a coupling agent. FA content is varied between 10 and 35 phr. The optimal formulation of FA/RP composites and experimental process variables were determined by measuring mechanical and thermal properties. A study of compatibility and cross-linking by SEM and IR shows that FA/RP composites offer superior mechanical and thermal properties when the accelerator (M) and stearic acid (SA) are added first, then mixed with sulfur and dicumyl peroxide (DCP), and finally r-Aminopropyltriethoxysilane (KH-550). The mass ratio of the FA/RP composites is 25/100, and the cure condition is 145°C for 40 min under 9 MPa. The results indicate that FA is an excellent filler and can be used as a silica replacement for reclaimed rubber powder composites.
Steam bubble cavitation
Authors: Mahulkar A. V. , Bapat P. S. , Pandit A. B. , Lewis F. M. 
Published: April 2008

AbstractGenerating hydrodynamic/ acoustic cavitation (Gogate et al.) for a useful purpose encompasses the following energy transformation steps: (1) Burning fuel in boiler. (2) Expanding the steam in a turbine generator. (3) Using electrical output from the generator to: (a) Pump water through a mechanical constriction (hydrodynamic cavitation), or (b) Operate ultrasonic transducer (acoustic cavitation). The combined loss, which is the mathematical product of each of the above step efficiencies, lowers the overall efficiency. An energy efficient method for generating useful cavitation is presented here. It suggests direct injection of steam (I) into sub‐cooled water to produce cavitation, thereby eliminating the inefficiencies of the remaining steps (II and III). Cavitation produced by this technique was experimentally and numerically shown to produce collapse conditions similar to hydrodynamic/acoustic cavitation. Direct steam injection cavitation coupled with acoustic cavitation, exhibited 4–16 times greater energy efficiency as compared to acoustic cavitation alone. Similar effects have been numerically speculated for hydrodynamic cavitation. © 2008 American Institute of Chemical Engineers AIChE J, 54, 2008
Nutrition transition in Amazonia: Obesity and socioeconomic change in the Suruí Indians from Brazil
Authors: Port Lourenço Ana Eliza , Ventura Santos Ricardo , Orellana Jesem D. Y. , Coimbra Carlos E. A. 
Published: April 2008

AbstractThe purpose of this study was to assess the nutritional status of the adult Suruí population, an indigenous society from the Brazilian Amazon, as it relates to socioeconomic conditions. Fieldwork was carried out in February–March 2005, including 252 individuals (88.1% of the total eligible subjects older than 20 years of age in the villages surveyed). Anthropometric measurements were performed following standard procedures, and percentage of body fat (%BF) was measured by bioimpedance. To classify the Suruí according to socioeconomic status (SES), an index was constructed based on a group of variables to characterize socioeconomic differentiation. Evaluated by body mass index (BMI), the majority of Suruí 20–49.9 years of age were overweight (42.3%) or obese (18.2%). The frequency of obesity for women (24.5%) was twice that recorded for men. Subjects classified as overweight or obese also showed high %BF and waist circumference (WC). Women in the high SES category showed higher anthropometric values (including weight, BMI, arm fat area, and WC) and %BF than those of lower SES. This study shows that the Suruí are undergoing a rapid process of nutrition transition. This transition is closely associated with the emergence of intragroup differences in SES which have impacted diet and physical activity patterns. In research in indigenous peoples in Amazonia, greater attention should be paid to the human biological outcomes of socioeconomic transformations related to the growing involvement of native societies in the market economy. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
A genome wide linkage scan for cleft lip and palate and dental anomalies
Authors: Vieira Alexandre R. , McHenry Toby G. , Daack‐Hirsch Sandra , Murray Jeffrey C. , Marazita Mary L. 
Published: April 2008

AbstractWe revisited 46 families with two or more siblings affected with an orofacial cleft that participated in previous genome wide studies and collected complete dental information. Genotypes from 392 microsatellite markers at 10 cM intervals were reanalyzed. We carried out four sets of genome wide analyses. First, we ran the analysis solely on the cleft status. Second, we assigned to any dental anomaly (tooth agenesis, supernumerary teeth, and microdontia) an affection status, and repeated the analysis. Third, we ran only the 19 families where the proband had a cleft with no dental anomalies. Finally, we ran only the 27 families that had a proband with cleft and additional dental anomalies outside the cleft area. Chromosomes (1, 2, 6, 8, 16, and 19) presented regions with LOD scores >2.0. Chromosome 19 has the most compelling results in our study. The LOD scores increased from 3.11 (in the scan of all 46 families with clefts as the only assigned affection status) to 3.91 when the 19 families whose probands present with no additional dental anomalies were studied, suggesting the interval 19p13.12‐19q12 may contain a gene that contributes to clefts but not to dental anomalies. On the other hand, we found a LOD score of 3.00 in the 2q22.3 region when dental anomalies data were added to the analysis to define affection status. Our preliminary results support the hypothesis that some loci may contribute to both clefts and congenital dental anomalies. Also, adding dental anomalies information will provide new opportunities to map susceptibility loci for clefts. © 2008 Wiley‐Liss, Inc.
Neurotransmission and bipolar disorder: A systematic family‐based association study
Authors: Shi Jiajun , Badner Judith A. , Hattori Eiji , Potash James B. , Willour Virginia L. , McMahon Francis J. , Gershon Elliot S. , Liu Chunyu 
Published: April 2008

AbstractNeurotransmission pathways/systems have been proposed to be involved in the pathophysiology and treatment of bipolar disorder for over 40 years. In order to test the hypothesis that common variants of genes in one or more of five neurotransmission systems confer risk for bipolar disorder, we analyzed 1,005 tag single nucleotide polymorphisms in 90 genes from dopaminergic, serotonergic, noradrenergic, GABAergic, and glutamatergic neurotransmitter systems in 101 trios and 203 quads from Caucasian bipolar families. Our sample has 80% power to detect ORs ≥ 1.82 and ≥1.57 for minor allele frequencies of 0.1 and 0.5, respectively. Nominally significant allelic and haplotypic associations were found for genes from each neurotransmission system, with several reaching gene‐wide significance (allelic: GRIA1, GRIN2D, and QDPR; haplotypic: GRIN2C, QDPR, and SLC6A3). However, none of these associations survived correction for multiple testing in an individual system, or in all systems considered together. Significant single nucleotide polymorphism associations were not found with sub‐phenotypes (alcoholism, psychosis, substance abuse, and suicide attempts) or significant gene–gene interactions. These results suggest that, within the detectable odds ratios of this study, common variants of the selected genes in the five neurotransmission systems do not play major roles in influencing the risk for bipolar disorder or comorbid sub‐phenotypes. © 2008 Wiley‐Liss, Inc.
Crystallization behavior and spherulite growth rate of isotactic polypropylene in isotactic polypropylene/natural rubber based thermoplastic elastomers
Authors: Joseph Aju , Koch T. , Seidler S. , Thomas S. , Joseph K. 
Published: April 2008

AbstractThe melting and crystallization behavior of isotactic polypropylene/natural rubber (PP/NR) based thermoplastic elastomers (TPEs) were investigated using differential scanning calorimetry. The samples were scanned at a heating rate of 10°C/min under nitrogen atmosphere. The effects of blend ratio on the melting and crystallization characteristics of the blends were analyzed. Normalized crystallinity is unchanged by the addition of small amount of NR, but as the amount of rubber increases crystallinity increased for the 30/70 NR/PP and lowered for the 50/50 NR/PP blend system. Morphology of the blend was analyzed using scanning electron microscopy (SEM). Blend ratio showed a pronounced influence on the phase morphology of the NR/PP TPEs. As the amount of NR increases more than 50 wt % the system changes from dispersed to cocontinuous structure. Hot‐stage polarizing optical microscopy (POM) was used to study the radial growth of spherulite as a function of blend ratio, cooling rate, and crystallization temperature. Spherulite growth rate is marginally influenced by the rubber inclusions. The spherulite morphology observed under polarized optical microscopy is influenced by the blend morphology. It was found that for the cocontinuous 50/50 blend system, spherulites are much different from the usual appearance under polarized light. Attempts have been made to correlate the crystallization behavior with the morphology of the blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of a methyl methacrylate/ethyl acrylate/acrylic acid terpolymer to improve the homogeneity of ethylene–propylene–diene monomer rubber/poly(vinyl chloride) blends
Authors: Botros S. H. , Moustafa A. F. , Mansour S. H. 
Published: April 2008

AbstractThe emulsion terpolymerization of methyl methacrylate (MMA), ethyl acrylate (EA), and acrylic acid (AA) was carried out under a nitrogen atmosphere at 70°C. The final terpolymer conversion was determined gravimetrically. The synthesized MMA–EA–AA terpolymer was characterized with 1H‐NMR spectroscopy, thermal analysis, and gel permeation chromatography. Glass‐transition temperatures of the MMA–EA–AA terpolymer were determined with a differential scanning calorimeter. Ethylene–propylene–diene monomer rubber (EPDM)/poly(vinyl chloride) (PVC) blends were prepared with different blend ratios (10/90, 20/80, 30/70, 40/60, and 50/50) in the presence and absence of MMA–EA–AA as a compatibilizer. The morphology of those blends was examined with the aid of a scanning electron microscope. The scanning electron micrographs in the presence of the MMA–EA–AA terpolymer illustrated the disappearance of the macroscale phase separation of EPDM/PVC blends as a result of the incorporation of MMA–EA–AA into that blend, indicating an improvement of the homogeneity. The mechanical properties of the EPDM/PVC blend films and the dielectric properties of the melt blends were investigated. The swelling behavior of the cured blends in the brake fluid was also discussed. The results illustrated that the mechanical properties, the weight swelling values, and the dielectric constant values showed linear behavior versus the blend ratios after the incorporation of the terpolymer. However, those values showed deviations from linearity in the absence of the terpolymer. That, in turn, ensured the results obtained with the scanning electron microscope. The results reveal that the MMA–EA–AA terpolymer prepared can be used successfully to improve the homogeneity of EPDM/PVC blends used in hose and oil seal applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of unsaturated poly(ε‐caprolactone) with a new titanium alkoxide initiator
Authors: Xia Zhean , Zerroukhi Amar , Chalamet Yvan , Chen Jianding 
Published: April 2008

AbstractTitanium alkoxides are widely used in the ring‐opening polymerization of ε‐caprolactone. In this study, functional poly(ε‐caprolactone) was synthesized with a new titanium initiator by a two‐step procedure: First, the titanium initiator, with an unsaturated group, was prepared by a classical organic reaction between 2‐hydroxyethylmethacrylate or 2‐allyloxyethanol with titanium tetrapropoxide; then, we initiated the polymerization of the ε‐caprolactone monomer in a glass reactor or twin‐screw extruder. By means of NMR spectroscopy, the structures of the initiators and polymers were determined. When 2‐hydroxyethylmethacrylate was used, there was a side reaction (transesterification) during the preparation of the initiator, and so it was impossible to obtain the expected product. With 2‐allyloxyethanol, the designed titanium initiator was synthesized with high purity, and the allyl moiety remained intact after the polymerization of ε‐caprolactone. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Cationic copolymerization of epoxy siloxane monomer with liquid poly‐butadiene and its light emitting diode encapsulation
Authors: Morita Yasumasa , Tajima Seitarou , Suzuki Hiroshi , Sugino Hiroaki 
Published: April 2008

AbstractA novel epoxy siloxane hybrid was prepared using epoxy siloxane monomers of 1,3‐bis[2‐(3‐{7‐oxabicyclo[4.1.0]heptyl})ethyl]‐tetramethyldisiloxane (BEPDS) with hydroxyl terminated hydrogenated polybutadiene (GI‐1000), in different proportions. Apparent polymerization reactivity was decreased with increasing GI‐1000 concentration but the normalized reactivity per epoxy group was slightly increased due to reaction between hydroxyl group and epoxy group. Increasing GI‐1000 concentration showed significant flexibility improvement in epoxy siloxane hybrid. At 30 wt % of GI‐1000 addition, glass transition temperature was decreased from 116 to 21°C and shore D hardness was decreased from 75 to 46.5% weight loss temperature of these epoxy siloxane hybrid was decreased with increasing GI‐1000 concentration, whereas thermal discoloration was increased. LED encapsulation with this epoxy siloxane demonstrated no crack when GI‐1000 was 30 wt % or more. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of poly(methyl methacrylate) beads
Authors: Holmes Rohan L. , Burford Robert P. , Bertram Christopher D. 
Published: April 2008

AbstractFor fluid‐dynamic experiments involving concentrated suspensions and complex geometries, particles which are neutrally buoyant and which have the same refractive index as both the suspending fluid and the bounding container are needed. Poly(methyl methacrylate) (PMMA) particles can meet these requirements simultaneously. Therefore monodisperse beads with the refractive index and density of pure PMMA were needed. For comparison with particle migration theory, it is also important that bead size and sphericity be accurately controlled. In our fluid mechanics experiments, 500‐μm diameter was required, a size where suspension polymerization is suitable. This article describes the controlled formation of PMMA beads in substantial quantities with desired size and a narrow particle size distribution. Reaction scale‐up using a 2‐L Büchi reactor allowed batch yields of 200 g of PMMA beads with desired shape and size. However, microcavities reduced bead density and optical clarity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and viscosity of hydrophobically modified polymers containing dendritic segments
Authors: Ali Shaikh A. , Umar Yunusa , Al‐Muallem Hasan A. , Abu‐Sharkh Basel F. 
Published: April 2008

AbstractThe cycloterpolymerizations of a newly synthesized dendritic quadruple‐tailed hydrophobic diallylammonium chloride with the hydrophilic monomer N,N‐diallyl‐N‐carboethoxymethylammonium chloride and sulfur dioxide afforded a series of water‐soluble cationic polyelectrolytes (CPEs) containing various proportions (0–1 mol %) of the hydrophobe. At a shear rate of 0.36 s−1 at 30°C, salt‐free water solutions of the CPEs (4 g/dL) containing 0, 0.35, 0.53, 0.65, and 0.93 mol % of the hydrophobe had apparent viscosity values of 140, 1200, 180,000, 308,000, and 858,000 cps, respectively. The study clearly demonstrated an increase in the viscosity values with increasing incorporation of the hydrophobes. The CPEs on acidic hydrolysis of the pendant ester groups gave corresponding pH‐responsive cationic acid salts, which upon treatment with NaOH, were converted to the polybetaines (PBs), anionic polyelectrolytes (APEs), and PB/APEs containing various proportions of PB and APE fractions in the polymer chain. The effects of charge type and charge density on the polymer chain were investigated. Polymer surfactant interactions were investigated with the cationic surfactant cetyltrimethylammonium bromide; a considerable increase in the viscosity values of the CPE was observed in the presence of the surfactant. The superior viscosity behavior for the polymers containing the quadruple‐tailed hydrophobe was attributed to the blocky nature of the comonomer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of 3′,4′‐disubstituted terthiophenes—Characterization and electropolymerization. II. 3′‐bromo‐4′‐thienyl‐2,2′:5′,2′‐terthiophene and 3′,4′‐diphenyl‐2,2′:5′,2′‐terthiophene in photovoltaic displays
Authors: Vélez J. H. , Díaz F. R. , del Valle M. A. , Bernéde J. C. , Soto J. P. 
Published: April 2008

AbstractIn a previous work 3′,4′‐dibromo substituted polythiophene film was used to produce an electronic device with photovoltaic characteristic but only 0.006% yield was achieved. In an effort to understand the reason of this low‐yield, we intend to elucidate the effect of substituents of terthiophene compounds on the morphological characteristics and conductivity of the electrochemical deposit. Thus, in this article we describe the electrochemical properties of thin films of poly(3′,4′‐diphenyl‐2,2′:5′,2″‐terthiophene), and poly(3′‐bromo‐4′‐thienyl‐2,2′:5′,2″‐terthiophene), the studies of electropolymerization using cyclic voltammetry, the determination of nucleation and growth mechanism using potential steps, and the morphology. Furthermore, a ZnO/Polymer/PTCDA/Li/Al photovoltaic cells have been devised and their I–V characteristics studied in the presence and in the absence of light. Incorporation of 3,4‐9,10‐tetracarboxylic dianhydride, PTCDA, as acceptor, induces a wider absorption spectrum in the visible region. Study of the photovoltaic efficiency, that increased with a decrease of the polymeric coating thickness, which in turn, is related to the number of voltammetric cycles, was also accomplished, but the desired thickness was never obtained without missing the electronic properties. Thus, even if the polymeric layer had the appropriate structure, this study corroborates that, to prepare the deposit, the electrochemical parameters must be previously controlled so as to obtain the thickness and morphology that render the best response. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Local citation analysis, publishing and reading patterns: Using multiple methods to evaluate faculty use of an academic library's research collection
Authors: Wilson Concepción S. , Tenopir Carol 
Published: April 2008

AbstractThis study assessed the intermix of local citation analysis and survey of journal use and reading patterns for evaluating an academic library's research collection. Journal articles and their cited references from faculties at the University of New South Wales were downloaded from the Web of Science (WoS) and journal impact factors from the Journal Citation Reports. The survey of the University of New South Wales (UNSW) academic staff asked both reader‐related and reading‐related questions. Both methods showed that academics in medicine published more and had more coauthors per paper than academics in the other faculties; however, when correlated with the number of students and academic staff, science published more and engineering published in higher impact journals. When “recalled” numbers of articles published were compared to “actual” numbers, all faculties over‐estimated their productivity by nearly two‐fold. The distribution of cited serial references was highly skewed with over half of the titles cited only once. The survey results corresponded with U.S. university surveys with one exception: Engineering academics reported the highest number of article readings and read mostly for research related activities. Citation analysis data showed that the UNSW library provided the majority of journals in which researchers published and cited, mostly in electronic formats. However, the availability of non‐journal cited sources was low. The joint methods provided both confirmatory and contradictory results and proved useful in evaluating library research collections.