bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the curing process of QY8911‐3 resin
Authors: Yang De'an , Li Zhaoyang , Lu Yan , Xu Tingxian 
Published: July 2003

AbstractThe effect of t‐butyl peroxybenzoate (TBPB) on the cure reaction of QY8911‐3 resin (BMI) was studied by differential scanning calorimetry (DSC) and gel time analysis. The mechanical properties of the resin and the composite were tested and analyzed with the peroxide content. The results showed that TBPB decomposed between 117 and 191°C and the enthalpy was 1123 J/g. TBPB reduced the initial reaction temperature, prompted the reaction speed, and shortened the gel time of the BMI resin. TBPB also increased the bending strength and decreased the impacting strength of the postcured samples. So, the peroxide content should be less than 0.6%. CF/SiO2/BMI composites were prepared from the BMI containing peroxide and their microstructure and properties were better than those of the composites free of peroxide. According to the injection‐molding experiment, the spilling problem was overcome and the forming time was reduced from 2 h to 15 min when peroxide was added. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3769–3773, 2003
Toughening of polylactide by melt blending with linear low‐density polyethylene
Authors: Anderson Kelly S. , Lim Shawn H. , Hillmyer Marc A. 
Published: July 2003

AbstractMelt blending of polylactide and linear low‐density polyethylene (LLDPE) was performed in an effort to toughen polylactide. In addition, two model polylactide‐polyethylene (PLLA‐PE) block copolymers were investigated as compatibilizers. The LLDPE particle size and the impact resistance of binary and ternary blends were measured to determine the extent of compatibilization. For the amorphous polylactide (PLA), toughening was achieved only when a PLLA‐PE block copolymer was used as a compatibilizer. For the semicrystalline polylactide (PLLA), toughening was achieved in the absence of block copolymer. To decrease the variability in the impact resistance of the PLLA/LLDPE binary blend, as little as 0.5 wt % of a PLLA–;PE block copolymer was effective. The differences that were seen between the PLA and PLLA binary blends were investigated with adhesion testing. The semicrystalline PLLA did show significantly better adhesion to the LLDPE. We propose that tacticty effects on the entanglement molecular weight or miscibility of polylactide allow for the improved adhesion between the PLLA and LLDPE. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3757–3768, 2003
Epoxy/alumina nanoparticle composites. I. Dynamic mechanical behavior
Authors: Vassileva E. , Friedrich K. 
Published: July 2003

AbstractWe studied the influence that alumina nanoparticle addition has on the dynamic mechanical spectra of an amino‐cured epoxy resin. A suppression of the short‐scale cooperative motions related to the β relaxation and an increase in the activation energy for the β relaxation of the epoxy matrix was observed as the alumina content increased. This is explained in terms of an antiplasticization effect of the alumina nanoparticles on the epoxy resin. An estimation of the effective thickness of the nanoparticle–matrix interfacial region was done based on the reduced damping. The dependence of the composites' reduced modulus on the alumina nanoparticles content is very well fitted by the generalized Kerner equation. The best‐fit parameter values suggest the presence of small and strong agglomerates in the composites at room temperature. At temperatures above the Tg, these agglomerates start to behave as weak ones because of the polymer matrix softening and particle–particle and particle–matrix slippage and friction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3774–3785, 2003
Synthesis and characterization of organosoluble poly(arylate‐imide)s prepared from direct polycondensation of bis(trimellitimide)‐diacids and various bisphenols
Authors: Yang Chin‐Ping , Chiang Hsun‐Ching , Chen Ruei‐Shin 
Published: July 2003

AbstractThree diimide‐diacids, 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]hexafluoropropane (I‐A), 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]propane (I‐B), and 5,5′‐bis[4‐ (4‐trimellitimidophenoxy)phenyl]hexahydro‐4,7‐methanoindan (I‐C), were prepared by the azeotropic condensation of trimellitic anhydride with three analogous diamines. Three series of alternating aromatic poly(arylate‐imide)s, having inherent viscosities of 0.41–0.82 dL/g, were synthesized from these diimide‐diacids (I‐A, I‐B, and I‐C) with various bisphenols by direct polycondensation using diphenyl chlorophosphate and pyridine as condensing agents. All of the polymers were readily soluble in a variety of organic solvents such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, and even in the less polar tetrahydrofuran. These polymers could be cast into transparent and tough films, which had strength at break values ranging from 73 to 98 MPa, elongation at break from 6 to 11%, and initial modulus from 1.6 to 2.2 GPa. The softening temperatures of the polymers were recorded at 145–248°C. They had 10% weight loss at a temperature above 450°C and left 35–51% residue even at 800°C in nitrogen. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3818–3825, 2003
Effect of polymer microstructure on dye diffusion in polyamide 66 fibers
Authors: Vasanthan Nadarajah , Huang Xin‐Xian 
Published: July 2003

AbstractOur previous work showed that drawing polyamide 66 (PA 66) fibers at room temperature does not change the degree of crystallinity, but only increases the molecular orientation. We therefore have used a series PA 66 fibers with different draw ratios to establish a direct correlation between (noncrystalline) molecular orientation fa and the dye diffusion coefficient D. For both acid and disperse dyes, the relationship log D ∝ f provides reasonable fits to the data for PA 66 fibers, and a similar relationship appears to be applicable to PA 6 fibers. Heat‐setting the fibers results in a continuous decrease in diffusion coefficient; unlike PA6 and PET fibers, no minimum in D was found in the region of 160°C. If this decrease in D is attributed to the increase in volume fraction crystallinity X taking place during heat‐setting, it must be deduced that log D ∝ X6. This dependence is surprisingly strong, but is consistent with observations we have made on PET and PA6 fibers. It is possible that some other structural rearrangement is partially or largely responsible for the decrease in diffusion coefficient, but Fourier transform infrared, density, and X‐ray diffraction measurements do not indicate any other structural changes taking place. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3803–3807, 2003
Thermal properties relevant to the processing of PET fibers
Authors: De Clerck K. , Rahier H. , Van Mele B. , Kiekens P. 
Published: July 2003

AbstractThe thermal properties of poly(ethylene terephthalate) (PET) conventional fibers and microfibers are measured and compared to bulk samples. It is shown that the glass transition temperature (Tg) of the fibers can be monitored with modulated differential scanning calorimetry (MDSC). The Tg region is about 30°C wide and shifted to approximately 110°C for conventional as well as for micro‐PET fibers. The Tg of these fibers is compared to the Tg of cold‐crystallized bulk samples. Upon crystallization, a shift and even a split up of Tg is observed. The second Tg is much broader and is situated around 90°C. This Tg is related to the appearance of a rigid amorphous phase. In comparison, the mobility of the amorphous phase in fibers is even more restricted. The whole multiple melting profile observed on the fibers is the result of a continuous melting and recrystallization process, in contrast to bulk PET. The heat‐set temperature is shown to trigger the start of melting and recrystallization. It is seen in the MDSC as an exotherm in the nonreversing signal and an excess contribution in the heat‐capacity signal. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3840–3849, 2003
Simulation of continuous solid‐phase polymerization of nylon 6,6. III. Simplified model
Authors: Yao K. Zhen , McAuley Kim B. , Marchildon E. Keith 
Published: July 2003

AbstractSolid‐phase polymerization (SPP) reactors are used to increase the degree of polymerization (DP) during nylon 6,6 production. In previous articles, a reactor model with partial differential equations (PDEs) in time and two spatial dimensions was developed to describe dynamic changes in polymer property profiles (DP, temperature, and moisture content) over the height of the reactor and within the polymer particles. In the current article, a simplified model is developed by deriving appropriate expressions for heat‐ and mass‐transfer coefficients and performing a lumped heat‐ and mass‐transfer analysis. Using this approach, the radial dimension is removed from the PDEs, so that the effort required to solve the model equations is substantially reduced. Predictions of the complex and simplified models are compared through simulation of two different start‐up processes. Good agreement between simplified and complex models is obtained, indicating that the simplified model can be used in place of the complex model if the polymer properties profiles within individual particles are not of particular concern to the model user. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3701–3712, 2003
Evaluating chitosan/β‐tricalcium phosphate/poly(methyl methacrylate) cement composites as bone‐repairing materials
Authors: Ming Kuo Shyh , Jen Chang Shwu , Lin Li‐Chun , Jung Chen Ching 
Published: July 2003

AbstractThis study related to the preparation of chitosan microspheres by means of reacting chitosan with β‐tricalcium phosphate (β‐TCP) and glutaraldehyde by crosslinking reaction in the oil phase, followed by de‐oil and purification processes to get the product. Three cement composites, Pure P, C1P1, and C2P1, were prepared by the polymerization of poly(methyl methacrylate) (PMMA) bone cement in the presence of 0, 50, and 66.7% chitosan/β‐TCP microspheres, respectively. The result revealed the chitosan/β‐TCP microspheres obtained was in the size range of 50–150 μm. The presence of chitosan/β‐TCP microspheres in the prepared composites decreased the ultimate tensile strength, whereas the modulus remained the same as compared with the commercial PMMA bone cement. Addition of chitosan/β‐TCP microspheres into commercial PMMA cement significantly improved the handling property of the cement paste—that is, the increased setting time and less stickiness behavior of this paste was beneficial, in manipulation, to the operation and easier fittings to the shape and gap of the bony defect and interface. The decreased curing temperature was also less harmful to the surrounding tissues. From scanning electron micrograph observations, chitosan/β‐TCP microspheres can completely mix with bone cement powder and the prepared composites could provide scaffold for osteoblast cells growth and thus improve defects of commercial PMMA bone cement. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3897–3904, 2003
Photosensitizing properties of ionic porphyrins immobilized on functionalized solid polystyrene support
Authors: Johnson Inbaraj J. , Vinodu Mikki V. , Gandhidasan R. , Murugesan R. , Padmanabhan M. 
Published: July 2003

AbstractThe photogeneration of singlet oxygen (1O2) by tetrasodium salt of meso‐tetrakis(4‐sulfonatophenyl)porphyrins (H2TPPS) and some of its metal complexes (MTPPS; M = Cd2+, Zn2+), immobilized on cationically functionalized polystyrene (PS) beads, was studied. The generation of 1O2 was monitored by a N,N‐dimethyl‐4‐nitrosoaniline (RNO) bleaching assay. The rate of RNO bleaching was seen to be retarded in the presence of DABCO, a specific 1O2 scavanger, providing evidence for the involvement of 1O2 as an active intermediate. The relative efficiencies of the generation of 1O2, with respect to immobilized rose bengal (PS–RB), by different polymer‐supported porphyrins, were determined to be 0.29, 0.27, and 0.16 for PS–H2TPPS, PS–ZnTPPS, and PS–CdTPPS, respectively. Binding of porphyrins to a polymer has been found to decrease the efficiency of the 1O2 generation, which could be attributed to the structural deformation of the appended porphyrins. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3925–3930, 2003
Studies on acrylic acid–grafted polyester fabrics by electron beam preirradiation method. I. Effects of process parameters on graft ratio and characterization of grafting products
Authors: He Chengcheng , Gu Zhenya 
Published: July 2003

AbstractPolyester fabrics were preirradiated by electron beam in air and then grafted by acrylic acid (AA) without excluding oxygen. Effects of preirradiation dose, monomer concentration, reaction temperature, storage time, sulfuric acid, and Mohr's salt were investigated in detail and are discussed. The results suggest that it is practicable and effective to graft AA onto polyester fabrics by means of the preirradiation method. FTIR and SEM were used to characterize AA‐grafted polyester fabrics. A new band appearing at 1546 cm−1 in the FTIR spectrum implies that AA was indeed introduced onto PET macromolecules. Changes of the diameter and the surface structure of fabric fibers presented in SEM micrographs make it clear that a layer of grafted poly(acrylic acid) was formed on the surface of these PET fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3931–3938, 2003
Kinematics of 11 Bidelman's weak‐lined stars
Authors: Bartkevičius A. , Sperauskas J. 
Published: July 2003

AbstractRadial velocities obtained with the CORAVEL‐type spectrometer are presented for 11 Bidelman's weak‐lined stars, classified from moderate dispersion objective prism spectra. Standard errors of the measurements are smaller than 1 km/s. For five of these stars, measured in the Vilnius photometric system, only small metal deficiency is established. Kinematically, most of the stars belong to the thin disk and only two stars, HD 71185 and BD +75° 641, are consistent with membership of the thick disk population.
A QSO survey via optical variability and zero proper motion in the M92 field. V. Completion of the QSO sample
Authors: Meusinger H. , Brunzendorf J. , Laget M. 
Published: July 2003

AbstractWe present results from the spectroscopic follow‐up observation of additional QSO candidates in the variability and proper motion (VPM) survey field around M92. In the previous studies, the VPMsurvey has shown to be an efficient way to select QSOs; the QSO sample was confined to the magnitude range B ≲ 19.8 with a completeness estimated to ∼ 90% for B ≲ 19.5. Here we study the faint end (B > 19.8) of the candidate list and check the completeness of the brighter (B < 19.7) QSO subsample. We first study an additional 34 brighter QSO candidates selected by FOCA UV brightness, radio detection, or optical colours. Only one new QSO was found. We show that a two‐colour search making use of FOCA 2 000 magnitudes efficiently selects QSOs, Seyfert galaxies, and NELGs. However, there is no QSO found from this method which would not have been selected by the VPM method as well. The main aim of this paper is to identify the VPM QSO candidates with 19.8 < B < 20.5. We select 53 candidates of which 50 were observed; 26 QSOs, 2 Sey1, and 2 NELGs were found. The fraction of QSOs and Sey1s among the faint high‐priority candidates amounts to 71%. The whole AGN sample comprises now 123 QSOs and 18 Sey1s. We find that the extended VPM QSO sample does not significantly differ from other optically selected samples with regard to their low‐resolution spectra and optical broad‐band colours.
Angular velocity during the cycle deduced using the sunspot group age selection methodology
Authors: Zuccarello F. , Zappalá R.A. 
Published: July 2003

AbstractWe have used the “age selection methodology” (ASM) (Zappalá and Zuccarello 1991) to study the variability of the sunspot groups angular velocity during the activity cycle. The ASM allows us to separate the contribution of Young Sunspot Groups (YSG) from that of Recurrent ones (RSG) in the Ω(θ) determination and therefore to evaluate whether the increase in angular velocity during minima (reported in literature using all sunspot groups as tracers), is due to a greater statistical weight of YSG on RSG or whether it reflects a global characteristic of the Sun. The results obtained from the analysis of sunspot groups data collected during the period 1874‐1981 (Greenwich Photoheliographic Results) indicate that during minima, besides the fact that the percentage of RSG drops to ≤ 5%, both YSG and RSG show the same increase in angular velocity, i.e. 0.16 degrees/day. Comparing our results with those reported in literature and taking into account the internal angular velocity as deduced by p‐mode oscillations, it is possible to conclude that the observed higher angular velocity of the Sun during minima concerns several layers of the Sun.
Theoretical model of a magnetic white dwarf
Authors: Bednarek I. , Brezina A. , Mańka R. , Zastawny‐Kubica M. 
Published: July 2003

AbstractIn this paper a theoretical model of a magnetic white dwarf is studied. All numerical calculations are performed under the assumption of a spherically symmetric star. The obtained equation of state is stiffer with the increase of value of the magnetic field (B). Numerical values of the maximum mass and radius are presented. The influence of the magnetic field on the results is evident. Finally the departure from the condition of isothermality of a degenerate electron gas in the gravitational field is discussed.
Symbolic analytical solutions for the abundances differential equations of the Helium burning phase
Authors: Nouh M.I. , Sharaf M.A. , Saad A.S. 
Published: July 2003

AbstractIn this paper, a literal analytical solution is developed for the abundances differential equations of the helium burning phase in hot massive stars. The abundance for each of the basic elements 4He,12C,16O and 20Ne is obtained as a recurrent power series in time, which facilitates its symbolic and numerical evaluations. Numerical comparison between the present solution and the numerical integration of the differential equations for the abundances show good agreement.
Astrometric detection of binary companions and planets: Acceleration of proper motion
Authors: Kaplan G.H. , Makarov V.V. 
Published: July 2003

AbstractApparent acceleration of proper motion is one of the observable manifestations of orbital motion in binary stars. Owing to the increasing accuracy of astrometric measurements, it may also be a method to detect binarity of stars. This paper presents some analytical expressions for the effects of binary motion on proper motions when the orbital period is at least several times the span of observations. We estimate orbit dimensions and distances at which low‐mass companions and planets may be detected around main‐sequence stars, using preliminary estimates of precision for the AMEX, GAIA and SIM space missions.
Diarrhea: A new risk factor for neural tube defects?
Authors: Felkner Marilyn , Hendricks Kate , Suarez Lucina , Waller D. Kim 
Published: July 2003

AbstractBACKGROUNDNeural tube defects (NTDs) affect approximately 4000 US pregnancies annually. Folic acid supplementation taken before conception protects against the occurrence of NTDs. Adequate levels of vitamin B12 also appear to play a significant role. Gastrointestinal disturbances, such as those caused by diarrhea, might negatively affect the availability of these vitamins, thereby increasing the risk of these birth defects.METHODSTo determine whether periconceptional diarrhea increases the risk of NTD‐affected pregnancies, a population‐based case‐control study was conducted in the 14 Texas–Mexico border counties. Information on diarrhea and other risk factors was ascertained by in‐person interview. Study subjects were Mexican‐American women who resided and delivered in any border county during 1995–2000. Case women, identified through active surveillance, had liveborn or stillborn infants or fetuses diagnosed with anencephalus, spina bifida, or encephalocele. Control women were randomly selected from women delivering normal live births in study area health facilities.RESULTSOne or more episodes of periconceptional diarrhea were associated with increased risk of NTD‐affected pregnancies compared to no episodes of diarrhea (OR = 3.7, 95% CI = 1.8–7.6). This association was independent of fever, obesity, maternal age, maternal birthplace, income, prior unproductive pregnancy, and dietary plus multivitamin folate intake, known risk factors for NTDs.CONCLUSIONSConfirmation of this new risk factor might have public health implications due to the feasibility of modifying exposure. Birth Defects Research (Part A) 67:504–508, 2003. © 2003 Wiley‐Liss, Inc.
Low maternal alcohol consumption during pregnancy and oral clefts in offspring: The Slone birth defects study
Authors: Meyer Katie A. , Werler Martha M. , Hayes Catherine , Mitchell Allen A. 
Published: July 2003

AbstractBACKGROUNDThe association between maternal alcohol consumption during pregnancy and oral clefts in offspring remains unclear. We studied this relation in a case–control surveillance study of birth defects.METHODSFrom 1983 to 1997, we recruited 5956 study subjects from greater Boston, Philadelphia, Toronto, and parts of Iowa. The cases were liveborn infants with cleft palate alone (CP; n = 205), cleft lip and palate (CLP; n = 383), cleft lip alone (CL; n = 259), or Pierre‐Robin sequence (n = 65). The controls (n = 4272) were infants who had no oral clefts but had one or more of the following defects: malformations of the digestive tract, reproductive organs, abdominal wall, and respiratory tract; chromosomal anomalies; inguinal hernia; tumors; and Mendelian inherited disorders. Based on maternal reports of alcohol consumption during the first 4 months of pregnancy, we derived average weekly consumption, average number of drinks per drinking day, and the maximum number of drinks consumed in a given day. The mothers also provided data on potential confounding or modifying variables, such as vitamin supplement use.RESULTSThere was no relation between maternal alcohol consumption during pregnancy and CL or CP. The odds ratios (ORs) for cleft lip with or without palate (CL/P) were 1.0, 1.1, and 0.9 in women who consumed <1.0, 1.0–2.9, and 3.0 + drinks per week, respectively. These findings did not change when we considered possible modifying effects of vitamin supplement use.CONCLUSIONSOur findings do not support an association between oral clefts and a low level of alcohol consumption. Birth Defects Research (Part A) 67:509–514, 2003. © 2003 Wiley‐Liss, Inc.
Birth defects in the offspring of non‐Caucasian, non‐Indigenous women in Western Australia
Authors: Kwon Seonghee , Bower Carol , English Dallas 
Published: July 2003

AbstractBACKGROUNDBirth defects in infants born to non‐Caucasian, non‐Indigenous mothers in Australia have not been described in detail previously.METHODSUsing data from the Western Australian Maternal and Child Health Research Data Base, an index cohort of all non‐Caucasian, non‐Indigenous mothers giving birth in Western Australia between 1985 and 1995 (n = 17,706 births) was compared with a 10% random sample of births to Caucasian mothers (n = 24,180) over the same period.RESULTSOverall, the index mothers had a 21% less risk of having a baby with birth defects (prevalence ratio, 0.79; 95% confidence interval, 0.72–0.86). The six major countries of birth of the index mothers were Vietnam, the Philippines, Singapore, Malaysia, India, and New Zealand. Mothers from Vietnam and the Philippines were significantly less likely to have a baby with a birth defect. The prevalences for the remaining four maternal countries of birth were not significantly different from that in the comparison cohort.CONCLUSIONSThe difference in risk of birth defects is probably not a result of confounding by maternal age, plurality, parity, socioeconomic status, marital status, or place of residence. However, it may be a real difference or a result of ascertainment bias. Birth Defects Research (Part A) 67:515–521, 2003. © 2003 Wiley‐Liss, Inc.