bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotational foam molding of polypropylene with control of melt strength
Authors: Pop‐Iliev Remon , Liu Fangyi , Liu Guobin , Park Chul B. 
Published: October 2003

AbstractPolypropylene (PP) has not been used extensively in rotational foam molding because it has been traditionally considered as nonfavorable for foaming applications because of its relatively weak melt strength and melt elasticity at elevated temperatures. However, because of the unique end‐use properties of PP, PP foams have recently grown in importance. An experimental study was conducted to identify feasible processing strategies for producing PP foams with satisfactory morphologies in dry‐blending‐based rotational foam molding. The obtained results revealed that cell coalescence plays a key role in the production of PP foams in rotational foam molding. If it is efficiently suppressed, the cell morphology of the PP foams improves dramatically. To suppress cell coalescence, it would be necessary to preserve the melt strength of PP during processing. One way of doing this is maintaining the temperature of the PP melt as low as possible. This can be accomplished by either lowering the decomposition temperature of the chemical blowing agent by using an activator such as zinc oxide and/or reducing the temperature of the oven. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 280–296, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10056
Influence of melt drawing on the morphology of one‐ and two‐step processed LDPE/thermoplastic starch blends
Authors: Rodriguez‐Gonzalez F. J. , Virgilio N. , Ramsay B. A. , Favis B. D. 
Published: October 2003

AbstractIn this study the morphology of LDPE/TPS blends prepared by a one‐step extrusion process is compared to that obtained by reprocessing of the original blends. The influence of composition and melt drawing is examined. A novel methodology based on the form factor of the dispersed particle was used to estimate the equivalent spherical particle size of dispersed thermoplastic starch (TPS). This approach allows for the quantitative comparison of average dispersed phase particles regardless of their shape. Blends prepared in the one‐step extrusion process show increased levels of anisotropy as a consequence of a combination of coalescence and particle deformation during melt drawing. Reprocessed materials demonstrate morphologies that are highly stable to a wide range of hot stretch ratio conditions. The TPS particles of reprocessed blends show no coalescence and a low degree of deformation. This phenomenon is explained by plasticizer evaporation resulting from the second processing step. The TPS is transformed from a highly deformable phase to one resembling a partially cross‐linked material. These data indicate that the one‐step processing of LDPE/TPS blends can be used to generate a wide range of highly elongated morphological structures. A two‐step approach, analogous to typical compounding and shaping operations and involving controlled glycerol removal in the second step can be used to prepare a wide range of highly stable, more isotropic, dispersed particle morphologies. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 297–305, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10057
Investigation of mold plate separation in thin‐wall injection molding
Authors: Chen Shia‐Chung , Liaw Wei‐Liang , Su Pao‐Lin , Chung Ming‐Hsiu 
Published: October 2003

AbstractPrecision injection molding of thin‐wall parts has become an important concern in 3C (computer, communication, and consumer electronics) plastics industry. Previous studies in precision injection molding control focused on the injection screw, the hydraulic system control and the associated operations.In the present study, the influence of relevant parameters, including injection speed, melt temperature, mold temperature, filling–packing switchover, and packing pressure, on the mold plate separation under different clamping pressures was investigated as part of precision molding control. A two‐cavity tensile test specimen mold equipped with four linear variable displacement transducers (LVDTs) on mold exteriors and across the parting surface was used for experiments. A PC‐based monitoring system was also built to detect the mold separation signals. Mold separation can also be identified from part weight variation and exhibits relevant correspondence with part weight. It was found that because of the high injection speed required for thin‐wall molding, mold separation is not negligible. In all situations, mold separation decreases with increasing clamping pressure. As melt temperature and mold temperature increase, mold separation increases, resulting in an increase of part weight. Similarly, when packing pressure and injection speed increase, mold separation also increases. Earlier switchover from filling to packing can decrease mold separation as well as part weight. Among all parameters, packing pressure exhibits the greatest influence on mold separation and the associated part weight change. Variation of melt temperature and mold temperature also changes the gate freezing time and the associated packing pressure distribution and mold separation. The influence also becomes larger when molding thin‐wall parts as compared with conventional injection molded parts because of the larger injection pressure required for molding. Simulations also show good correspondence with experimental measurements. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 306–319, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10058
Two‐phase flow in a gas‐injected capillary tube
Authors: Park Chan‐Seok , Baek Sang‐Youp , Lee Ki‐Jun , Kim Seong Woo 
Published: October 2003

AbstractThe characteristics of two‐phase flow in a gas‐assisted capillary tube were studied by experimental and numerical methods. Experiments were performed with five test fluids including two Newtonian fluids and three suspensions having yield stresses. The coating thickness of the fluids deposited on the tube wall was measured with the various fraction of the capillary volume occupied by the fluids. The fractional coverage increased monotonically as capillary number increased at low capillary number (Ca < 1), approaching an asymptotic value of 0.60 at high capillary number. The shape of the front and fractional coverage as a function of the capillary number could be obtained by numerical simulation based on a finite element method using Polyflow® software. It was found that the predicted results are in good agreement with the experimental results. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 320–328, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10059
Cure kinetics and properties of epoxy resins containing a phosphorous‐based flame retardant
Authors: Frigione M. , Maffezzoli A. , Finocchiaro P. , Failla S. 
Published: October 2003

AbstractA fire retardant phosphorous‐containing bisphenol compound, bis(3‐diethyl phosphono‐4‐hydroxyphenyl)‐sulfide (DPHS), has been inserted in an epoxy network. In particular, a chain extension procedure has been used to incorporate DPHS into a standard bisphenol epoxy resin. Different amine catalysts have been tested to promote the reaction of DPHS with the epoxy oligomer. The cure kinetics of this chain‐extended oligomer, using an aliphatic amine (triethylene‐tetraamine, TETA) as hardener, has been studied with the aid of differential scanning calorimetry and compared with that of the standard stoichiometric epoxy/TETA formulation. For each formulation the activation energy of the curing reactions has been evaluated by the Kissinger method. The results of thermogravimetric and flammability tests indicate that DPHS promoted the formation of a char, leading to an improved fire resistance. Finally, a comparison of the thermal and mechanical properties of the standard stoichiometric formulation relative to those of the epoxy modified with DPHS, and cured with TETA, showed only marginal changes in the physical and mechanical properties. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 329–342, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10060
The effect of boron nitride particles and hot‐pressed boron nitride die on the capillary melt flow processing of polyethylene
Authors: Lee Sang Myung , Nam Gi Joon , Lee Jae Wook 
Published: October 2003

AbstractThe processability of polymers by extrusion is closely related to the interface between the polymer melt and the die wall. The wall surface energy affects the flow of polymer melts in extrusion die. For the purpose of improving the processability in such a process, the effects of boron nitride (BN) powders on the rheological properties and the extrusion processability of metallocene‐ catalyzed low‐density polyethylene (m‐LDPE) have been investigated in this study. It is known that BN powders act as a solid lubricant, and lower the surface energy. Two kinds of BN particle, differing in crystal and agglomerate size, have been used and compared. The initial agglomeration of particles had little effect on the processing performance once the samples were made by twin‐screw extrusion. However, crystal size and size distributions significantly influenced the processability. Small crystal size and uniform size distribution were found to be more effective. Also, this improvement of processability was due to the increased slip velocity, not due to rheological property changes. The effect of a hot‐pressed BN die on the instability of capillary flow was also studied. A hot‐pressed BN die was quite effective in delaying surface and sharkskin defects and postponing gross melt fracture compared to a tungsten carbide die. A synergistic effect of processability improvement could be obtained when both BN powder and a hot‐pressed BN die were used together. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 343–354, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10061
Novel methacryloylamidophenylalanine functionalized porous chelating beads for adsorption of heavy metal ions
Authors: Say Ridvan , Emir Sibel , Garipcan Bora , Patir Süleyman , Denizli Adil 
Published: October 2003

AbstractThe purpose of this study was to investigate in detail the adsorption performance of poly(2‐hydroxyethylmethacrylate–methacryloylamidophenylalanine) [p(HEMA–MAPA)] beads. The metal‐complexing comonomer MAPA was synthesized by reacting methacryloyl chloride with phenylalanine. Spherical beads with an average size of 150–200 μm were obtained by radical suspension polymerization of HEMA and MAPA, conducted in an aqueous dispersion medium. The beads had a specific surface area of 19.1 m2/g, and were characterized by means of swelling studies, FTIR, and elemental analysis. Beads with a swelling ratio of 68% and containing 3.2 mmol MAPA/g were used for the removal of heavy metal ions. Adsorption experiments were conducted with the MAPA‐functionalized beads involving the heavy metal ions cadmium, arsenic, chromium, mercury, and lead. Metal adsorption was found to be dependent on the characteristics of the solution (i.e., medium pH and metal concentration) and the type of metals to be adsorbed. We have obtained adsorption capacities equal to 669.4 mg/g for Hg(II), 584.4 mg/g for Pb(II), 268.4 mg/g for Cd(II), 204.1 mg/g for As(III), and 115.2 mg/g for Cr(III). The adsorption capacities on molar basis were in the order of Hg(II) > Pb(II) > Cd(II) > As(III) > Cr(III). Adsorption of heavy metal ions from synthetic wastewater was also studied. The adsorption capacities were 24.5 mg/g for Cd(II), 16.9 mg/g for Cr(III), 144.4 mg/g for Hg(II), 90.9 mg/g for Pb(II), and 8.0 mg/g for As(III) at 0.5 mmol/l initial metal concentration. Naturally, depending on the desired goals,the beads containing metal could be regenerated for appropriate disposal. Our results suggest that p(HEMA–MAPA) beads are good metal adsorbers and have a great potential for environmental protection. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 355–364, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10062
Evaluation of UV inhibitors in polyester gelcoats
Authors: Capanescu Cezar , Cincu Corneliu 
Published: October 2003

AbstractThe performance of several UV inhibitors (light stabilizers and hindered amine light stabilizers) was investigated in a polyester gelcoat. The color change and the gloss retention were evaluated using several known accelerated lab test instruments and procedures, against real‐life outdoor weathering. Correlation between these methods and the real‐life data was suggested, along with a proposed model of the whole weathering process: upon outdoor exposure the color change (yellowing) occurs first, then after at least one year of weathering, the process of gloss loss also starts. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 365–372, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10063
Interlaminar shear strength of polycarbonate‐toughened epoxy composites reinforced with glass rovings
Authors: Rajulu A. Varada , Rao G. Babu , Devi L. Ganga , Balaji Perugu Jithendra , He Jiasong , Zhang Jun 
Published: October 2003

AbstractThe interlaminar shear strength (ILSS) of a composite containing glass rovings in a polycarbonate‐toughened epoxy matrix was determined. The variation of ILSS with glass rovings and polycarbonate content was studied. For a given content of polycarbonate in the matrix, the ILSS increased with volume fraction of the glass rovings. For a given rovings content, the ILSS decreased with increasing polycarbonate content. However, the ILSS of the composites with epoxy alone as the matrix is found to be higher than that of the epoxy/polycarbonate blend and this was attributed to better bonding between epoxy and reinforcement than that between epoxy/polycarbonate blend and reinforcement. This was further confirmed by scanning electron micrographs of ILSS fractured samples. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 373–377, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10064
Craniofacial‐deafness‐hand syndrome revisited
Authors: Sommer Annemarie , Bartholomew Dennis W. 
Published: October 2003

AbstractIn 1983 Sommer described a new syndrome in a mother and her infant daughter which was subsequently called the syndrome of craniofacial, hand anomalies and sensorineural deafness. The syndrome consisted of a normal calvarium with a flat facial profile, hypertelorism and small palpebral fissures with an antimongoloid slant, a depressed nasal bridge with a button tip and slitlike nares and a small “pursed” mouth. Profound sensorineural hearing loss and ulnar deviation of the hands with flexion contractures of digits three, four and five was evident. The family had another child, a son, two years after the birth of the index case that had the exact manifestations as his mother and sister. Because of three affected family members in two generations and a phenotype of midfacial anomalies and dystopia canthorum resembling Waardenburg syndrome, a search for mutations in the PAX3 gene was undertaken. A missense mutation in the paired domain of PAX3 (Asn47Lys) was detected. We have provided a 20‐year follow‐up of a syndrome characterized by craniofacial anomalies, hearing loss and hand deformities and which is caused by a PAX3 missense mutation. © 2003 Wiley‐Liss, Inc.
Adult height in Noonan syndrome
Authors: Noonan Jacqueline A. , Raaijmakers Renske , Hall Bryan 
Published: October 2003

AbstractShort stature is a very common manifestation of Noonan syndrome (NS) and is accompanied by a variable delay in bone age. Although reports of adult height in NS are uncommon, some feel growth hormone therapy will increase adult height. We report our findings in 73 adults over 21 years of age with NS. Thirty percent of this group had an adult height in the normal range between 10th percentile and 90th percentile. Over half of the females and nearly 40% of males had an adult height below the 3rd percentile. The presence or severity of heart disease was not a factor, and none of the adults with a normal height had been treated with growth hormone. Serial measurements of height for many years through childhood to adulthood were available in only a few patients, but their pattern of growth suggests catch up may occur in late adolescence. To evaluate the benefit of growth hormone therapy, long term serial height measurements over a period of years comparing treated and untreated patients are needed. It will be important to determine what role, if any, the mutated PTPN 11 gene plays in the short stature common in NS. © 2003 Wiley‐Liss, Inc.
Methotrexate/misoprostol embryopathy: Report of four cases resulting from failed medical abortion
Authors: Adam Margaret P. , Manning Melanie A. , Beck Anita E. , Kwan Andrea , Enns Gregory M. , Clericuzio Carol , Hoyme H. Eugene 
Published: October 2003

AbstractMethotrexate, a methyl derivative of aminopterin, is a folic acid antagonist and a known human teratogen; misoprostol is a synthetic prostaglandin E1 analog that causes uterine contractions. Recently, there has been resurgence in the use of methotrexate in combination with misoprostol or of methotrexate alone for the treatment of unwanted or ectopic pregnancies, respectively. This report documents the findings in four infants who were exposed prenatally to methotrexate alone or in combination with misoprostol in a failed attempt at medical abortion or treatment of ectopic pregnancy. All patients demonstrated growth deficiency, with growth parameters <10th centile, and all displayed features consistent with methotrexate and/or misoprostol embryopathy. Since an increasing number of medical abortions are being performed, it is important for physicians to recognize the associated teratogenic effects of these abortifacients. Data from the patients herein described should prompt obstetricians and other health care practitioners who prescribe these medications to counsel their patients regarding these risks, especially if the treatment regimen fails to induce an abortion. © 2003 Wiley‐Liss, Inc.
A new X‐linked syndrome with agenesis of the corpus callosum, mental retardation, coloboma, micrognathia, and a mutation in the Alpha 4 gene at Xq13
Authors: Graham Jr. John M. , Wheeler Patricia , Tackels‐Horne Darci , Lin Angela E. , Hall Bryan D. , May Melanie , Short Kieran M. , Schwartz Charles E. , Cox Timothy C. 
Published: October 2003

AbstractWe describe two brothers with a unique pattern of malformations that includes coloboma (iris, optic nerve), high forehead, severe retrognathia, mental retardation, and agenesis of the corpus callosum (ACC). Both boys have low‐set cupped ears with sensorineural hearing loss, normal phallus, pectus excavatum, scoliosis, and short stature. One brother had choanal atresia and cardiac defects consisting of ventricular septal defect (VSD) and patent ductus arteriosus (PDA) which resolved spontaneously. Differential diagnosis between a number of clinical entities was considered, however, because ACC and the distinctive facial features were reminiscent of FG syndrome, DNA was analyzed for markers linked to the FGS1 locus at Xq13‐q21. Notably, the brothers were concordant for markers spanning this presumed FG region, and in both we have identified adjacent alterations (−57delT and T‐55A) in the Alpha 4 gene located within this interval. Alpha 4 is a regulatory subunit of the major cellular phosphatase, PP2A, that has recently been shown to interact with MID1, the product of the gene mutated in X‐linked Opitz GBBB syndrome. The double nucleotide change identified in this family was not observed in 410 control chromosomes, suggesting that it may be a pathogenetic change. Altered expression of Alpha 4, through either a change in translational efficiency, mRNA stability or splicing, could explain the clinical phenotype in these boys and the phenotypic overlap with Opitz GBBB syndrome. © 2003 Wiley‐Liss, Inc.
Matrix decomposition model for investigating prehistoric intracemetery biological variation
Authors: Stojanowski Christopher M. 
Published: October 2003

AbstractA matrix decomposition model for analyzing prehistoric intracemetery biological variability is presented. The model, based on the correlation between interindividual biological and burial distance matrices, provides an estimate of the number of distinct burial populations interred within a single cemetery, which effectively ameliorates identifiability problems typical of general variability analyses (Raemsch [1995] Ph.D. dissertation, SUNY at Albany). Unlike other methods for analyzing intrasite variability analysis (e.g., kinship analysis and microchronology), this method is not reliant on a priori subgroup definition. Assuming a kin‐structured burial pattern, a residual matrix is defined based on the raw data matrices; the proportion of negative or zero residuals to the total number of residuals provides an estimate of the number of hidden subgroupings (lineages) within the cemetery. The comparative utility of the model is demonstrated on a series of protohistoric and historic period skeletal samples from the Georgia coast, where it demonstrated that the increase in phenotypic variability during the early mission period is the result of population aggregation at the missions and not necessarily genetic admixture between local and nonlocal groups. Am J Phys Anthropol 121:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Reconstruction of human evolutionary tree using polymorphic autosomal microsatellites
Authors: Ayub Qasim , Mansoor Atika , Ismail Muhammad , Khaliq Shagufta , Mohyuddin Aisha , Hameed Abdul , Mazhar Kehkashan , Rehman Sadia , Siddiqi Saima , Papaioannou Myrto , Piazza Alberto , Cavalli‐Sforza Luigi Luca , Mehdi S. Qasim 
Published: October 2003

AbstractAllelic frequencies of 182 tri‐ and tetra‐autosomal microsatellites were used to examine phylogenetic relationships among 19 extant human populations. In particular, because the languages of the Basques and Hunza Burusho have been suggested to have an ancient relationship, this study sought to explore the genetic relationship between these two major language isolate populations and to compare them with other human populations. The work presented here shows that the microsatellite allelic diversity and the number of unique alleles were highest in sub‐Saharan Africans. Neighbor‐joining trees based on genetic distances and principal component analyses separated populations from different continents, and are consistent with an African origin for modern humans. For the first time, with biparentally transmitted markers, the microsatellite tree also shows that the San are the first branch of the human tree before the branch leading to all other Africans. In contrast to an earlier study, these results provided no evidence of a genetic relationship among the two language isolate groups. Genetic relationships, as ascertained by these microsatellites, are dictated primarily by geographic proximity rather than by remote linguistic origin, Mantel test, R0 = 0.484, g = 3.802 (critical g value = 1.645; P = 0.05). Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.