bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Quantum‐Splitting Phosphor Exploiting the Energy Transfer from Anion Excitons to Tb3+ in CaSO4:Tb,Na
Authors: Lakshmanan A. R. , Kim S.‐B. , Jang H. M. , Kum B. G. , Kang B. K. , Heo S. , Seo D. 
Published: December 2006

AbstractWide‐bandgap materials doped with rare‐earth ions are currently of great interest as new vacuum ultraviolet (VUV) phosphors for lighting and displays. This paper reports the development of a highly sensitive green phosphor, CaSO4:Tb,Na, which exhibits a quantum efficiency higher than 100 % by exploiting the energy‐transfer mechanism from anion excitons to the activator ions, Tb3+. The VUV excitation spectra of CaSO4:Tb3+ with Na+ as a charge compensator show two prominent excitation bands at 147 and 216 nm. The former band is attributed to the charge‐transfer excitations within SO42– complexes while the latter was assigned to the 4f8 → 4f75d transitions on Tb3+. The energy‐transfer mechanism from anion excitons to Tb3+ strongly raises the possibility of two‐photon emission via a second‐order down‐conversion under the VUV excitation, which is basically a new approach in the goal of achieving a quantum‐splitting phosphor.
Fine Control of the Wettability Transition Temperature of Colloidal‐Crystal Films: From Superhydrophilic to Superhydrophobic
Authors: Wang J. , Wen Y. , Hu J. , Song Y. , Jiang L. 
Published: December 2006

AbstractA facile strategy for finely controlling the wettability transition temperature of colloidal‐crystal films from superhydrophilic (water contact angle, CA, 0°) to superhydrophobic (water CA, 150.5°) is demonstrated. The colloidal‐crystal films are assembled from poly(styrene‐n‐butyl acrylate–acrylic acid) amphiphilic latex spheres. The wettability transition temperature of the films can be well tuned by adjusting the n‐butyl acrylate/styrene balance of the latex spheres. Superhydrophobic films are achieved when assembled at 90, 80, 70, 60, 40, or even 20 °C. This approach offers the flexibility of fabricating colloidal crystals with desired and tunable wettability, and can be further extended to general materials, opening up new perspectives in controlling the wettability behavior by chemical composition.
Demographic review of a captive colony of callitrichids (Callithrix kuhlii)
Authors: Ross Corinna N. , Fite Jeffrey E. , Jensen Heather , French Jeffrey A. 
Published: December 2006

AbstractAlthough reports on colony demographics for a variety of callitrichid species are available in the literature, to date there has not been a detailed examination of Wied's black tufted‐ear marmoset (Callithrix kuhlii). The purpose of this study is to present colony demographics for C. kuhlii from the University of Nebraska at Omaha's Callitrichid Research Center from 1991 to 2002. C. kuhlii are currently held in a number of zoological parks in the United States and abroad; however, the University of Nebraska at Omaha held the only breeding colony in North America. Here we report data on lifespan, sex ratio, litter size, and interbirth interval (IBI) for that captive breeding colony. Am. J. Primatol. 69:1–7, 2007. © 2006 Wiley‐Liss, Inc.
Use of traps to capture black and gold howlers (Alouatta caraya) on the Islands of the upper paraná river, Southern Brazil
Authors: Aguiar Lucas M. , Ludwig Gabriela , Svoboda Walfrido K. , Teixeira Gustavo M. , Hilst Carmen L.S. , Shiozawa Marcos M. , Malanski Luciano S. , Mello Ângel M. , Navarro Italmar T. , Passos Fernando C. 
Published: December 2006

AbstractHowlers (genusAlouatta) are widely captured with the use of anesthetic projectiles; however, no capture protocol involving the use of traps has been described to date. In the present study we describe the first efficient capture program for black and gold howlers (Alouatta caraya) using traps, which was implemented on the islands of the upper Paraná River in southern Brazil. We constructed two trap models with either manual or automatic activation (trap A with two entrances and guillotine‐type doors; trap B with one entrance and a guillotine‐type door). The traps were suspended in the canopy by means of vertical climbing techniques, and were baited regularly and abundantly with bananas and mangoes. We captured 70 howlers (86% using manual activation and 14% using automatic activation) on four different islands. We restrained 41 of these animals and measured their body mass, which averaged 5.30 kg±1.79. Given our results, we suggest that the system described in the present study represents an alternative capture program for howlers in areas that have low food diversity and no other mammal species that will compete for the bait, as has been observed in riparian environments, islands, and forest fragments. Am. J. Primatol. 69:1–7, 2007. © 2006 Wiley‐Liss, Inc.
Demography and life history of Thomas langurs (Presbytis thomasi)
Authors: Wich Serge A. , Steenbeek Romy , Sterck Elisabeth H.M. , Korstjens Amanda H. , Willems Erik P. , Van Schaik Carel P. 
Published: December 2006

AbstractLife history data from wild primate populations are necessary to explain variation in primate social systems and explain differences between primates and other mammals. Here we report life history data from a 12.5‐year study on wild Thomas langurs. Mean age at first reproduction was 5.4 years and the sex ratio at birth was even. The mean interbirth interval (IBI) after a surviving infant was 26.8 mo, after nonsurviving infants 17.7 mo, and combined 22.0 mo. Mean annual birth rate of adult females was 0.44, while reaching a peak at 6 years of age and showing no decrease with age. Mortality was highest during the first year of life (48.0% for males and 43.0% for females) and consistently higher for males than females. The oldest female observed during the study was estimated to be 20 years of age, whereas the oldest male disappeared at age 13 years, indicating that males die at a much earlier age than females. A Leslie matrix based on these estimates yielded a growth rate of 1.01, which is comparable to the nonsignificant increase in density indicated by our long‐term field data. A comparison with life history data for sympatric frugivorous primates suggests that folivory might be associated with faster life history. Am. J. Primatol. 69:641–651, 2007. © 2006 Wiley‐Liss, Inc.
Grafted wood pulp containing quaternary ammonium group and its application in the removal of different anions from aqueous solution
Authors: Sokker H. H. 
Published: December 2006

AbstractNetwork wood pulp based on acrylonitrile (AN) has been chemically modified through different reactions to obtain group capable of anion exchange. Graft copolymerization of AN onto wood pulp was carried out by using γ‐radiation 60Co. Factors affecting the grafting process, e.g., radiation dose and monomer concentration, was investigated. The chemical modification of cyano groups were carried out by reaction with ethanolamine producing oxazoline group followed by quaternization of tertiary amine by reaction with benzyl chloride producing quaternary ammonium salt. The grafted and modified wood pulp were characterized by FTIR, SEM, and TGA. Qualitative adsorption experiments were conducted to evaluate the ability of modified wood pulp to fix sulfate, phosphate, nitrate, and dichromate from aqueous solution using batch extractions. Based on the results obtained, it may be concluded that it is possible to modify chemically wood pulp containing cyano groups by different routes to use it as anion exchanger for different anions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3120–3128, 2007
Effect of network heterogeneities on the physical properties of nitrile rubbers cured with dicumyl peroxide
Authors: González L. , Rodríguez A. , Marcos‐Fernández A. , Valentín J. L. , Fernández‐Torres A. 
Published: December 2006

AbstractThe scope of this study is to continue our earlier studies on the peroxide curing of diene elastomers. The effect of peroxide content and temperature on the curing and mechanical properties of NBR and H‐NBR rubbers with different acrilonitrile content was evaluated. Experimental evidence indicates that saturated rubbers behave as expected whereas in unsaturated nitrile rubbers abstraction of allylic hydrogen and addition to the double bonds can act as mechanism of crosslinking, the weight of each mechanism is dependent of DCP content and curing temperature. The addition mechanism produces densely crosslinked zones or clusters, generating a heterogeneous network with effect on the vulcanizate properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3377–3382, 2007
Calcium‐carboxymethyl chitosan hydrogel beads for protein drug delivery system
Authors: Liu Zonghua , Jiao Yanpeng , Zhang Ziyong 
Published: December 2006

AbstractIn this study, carboxymethyl chitosan (CMC) hydrogel beads were prepared by crosslinking with Ca2+. The pH‐sensitive characteristics of the beads were investigated by simulating gastrointestinal pH conditions. As a potential protein drug delivery system, the beads were loaded with a model protein (bovine serum albumin, BSA). To improve the entrapment efficiency of BSA, the beads were further coated with a chitosan/CMC polyelectrolyte complex (PEC) membrane by extruding a CMC/BSA solution into a CaCl2/chitosan gelation medium. Finally, the release studies of BSA‐loaded beads were conducted. We found that, the maximum swelling ratios of the beads at pH 7.4 (17–21) were much higher than those at pH 1.2 (2–2.5). Higher entrapment efficiency (73.2%) was achieved in the chitosan‐coated calcium‐CMC beads, compared with that (44.4%) in the bare calcium‐CMC beads. The PEC membrane limited the BSA release, while the final disintegration of beads at pH 7.4 still leaded to a full BSA release. Therefore, the chitosan‐coated calcium‐CMC hydrogel beads with higher entrapment efficiency and proper protein release properties were a promising protein drug carrier for the site‐specific release in the intestine. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3164–3168, 2007
Newly developed itaconic acid copolymers for gypsum and calcium carbonate scale control
Authors: Shakkthivel P. , Vasudevan T. 
Published: December 2006

AbstractTo mitigate scale formation and the consequences of clogging of filters and the reduction in efficiencies in cooling systems, itaconic acid–maleic acid (Ita–MA) and itaconic acid–methacrylic acid (Ita–MAA) copolymers were developed. Calcium sulfate and calcium carbonate scales formation have been prevented at temperatures ranging from 50 to 80°C using the newly developed polymers. The effect of the polymers on their scale‐arresting abilities has been assessed through chemical screening test, constant potential electrolysis, and A.C. impedance techniques. XRD (x‐ray diffraction) and SEM (scanning electron microscope) studies have been performed to identify the change in crystal surfaces by the addition of the polymers. The amount of scale deposition is increased with increase in both the temperature and the pHs of the medium. The efficacy of the polymers (antiscalants) on the scale prevention is increased with increase in polymer dosage. However, decrease in efficiency is noticed with increase in temperature and pHs. The results, at different dosage levels with different temperature and pHs, are critically discussed. Both of the scales have been inhibited, through the adsorption of the polymers onto the growth sites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3206–3213, 2007
Preparation and characterization of conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films
Authors: Chen Cheng‐Ho , Mao Ching‐Feng , Su Shun‐Fua , Fahn Yauh‐Yarng 
Published: December 2006

AbstractIn this study a solution‐blend method is adopted to prepare conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films. Emeraldine base (EB)‐type polyaniline (PANI) is dissolved in N‐methyl‐2‐pyrrolidinone (NMP) and then blended with PVA/dodecyl benzene sulfonic acid (DBSA) solution by various amounts. It is found that the electrical conductivity and the thermal degradation onset temperature of the PVA/PANDB blend film are increased as the amount of EB‐type PANI solution is increased. Fourier transform infrared (FTIR) spectra show that the intensity of the characteristic peak of the functional groups in the blend film is significantly changed as the amount of EB‐type PANI is changed. From optical microscopy examination, it indicates that the amount and size of green particles are increased with increasing the amount of EB‐type PANI solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3415–3422, 2007
Mechanical characterization and chemical resistances of cured unsaturated polyester resins modified with vinyl ester resins based on recycled poly(ethylene terephthalate)
Authors: Atta Ayman M. , Abdel‐Raouf Manar E. , Elsaeed Shimaa M. , Abdel‐Azim Abdel‐Azim A. 
Published: December 2006

AbstractUnsaturated polyester resin (UP) was prepared from glycolyzed oligomer of poly(ethylene terephthalate) (PET) waste based on diethylene glycol (DEG). New diacrylate and dimethacrylate vinyl ester resins prepared from glycolysis of PET with tetraethylene glycol were blended with UP to study the mechanical characteristics of the cured UP. The vinyl ester resins were used as crosslinking agents for unsaturated polyester resin diluted with styrene, using free‐radical initiator and accelerator. The mechanical properties of the cured UP resins were evaluated. The compressive properties of the cured UP/styrene resins in the presence of different vinyl ester concentrations were evaluated. Increasing the vinyl ester content led to a pronounced improvement in the compression strength. The chemical resistances of the cured resins were evaluated through hot water, solvents, acid, and alkali resistance measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3175–3182, 2007
Kinetic study of radical polymerization. VII. Investigation into the solution copolymerization of acrylonitrile and itaconic acid by real‐time 1H NMR spectroscopy
Authors: Reza Mahdavian Ali , Abdollahi Mahdi 
Published: December 2006

AbstractFree radical solution copolymerization of acrylonitrile (AN) and itaconic acid (IA) was performed with DMSO‐d6 as the solvent and 2,2′‐azobisisobutyronitrile (AIBN) as the initiator. Weight ratio of the monomers to solvent and molar ratio of initiator to monomers were constant in all experiments. The initial comonomer composition was the only variable in this study. On‐line 1H NMR spectroscopy was applied to follow individual monomer conversion. Mole fraction of AN and IA in the reaction mixture (f) and in the copolymer chain (F) were measured with progress of the copolymerization reaction. Overall monomer conversion versus time and also compositions of monomer mixture and copolymer as a function of overall monomer conversion were calculated from the data of individual monomer conversion versus time. Total rate constant for the copolymerization reaction was calculated by using the overall monomer conversion versus time data and then kp/kt0.5 was estimated. The dependency of kp/kt0.5 on IA concentration was studied and it was found that this ratio decreases by increasing the mole fraction of IA in the initial feed. The variation of comonomer and copolymer compositions as a function of overall monomer conversion was calculated theoretically by the terminal model equations and compared with the experimental data. Instantaneous copolymer composition curve showed the formation of alternating copolymer chain during copolymerization reaction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3253–3260, 2007
Isothermal‐crystallization kinetics and melting behavior of crystalline/crystalline blends of poly(trimethylene terephthalate) and poly(ethylene 2,6‐naphthalate)
Authors: Run Mingtao , Wang Yingjin , Yao Chenguang , Zhao Hongchi 
Published: December 2006

AbstractThe isothermal crystallization and crystal morphology of poly(trimethylene terephthalate) (PTT)/poly (ethylene 2,6‐naphthalate) (PEN) blends were investigated with differential scanning calorimetry and polarized optical microscopy. The commonly used Avrami equation was used to fit the primary stage of isothermal crystallization. The Avrami exponents were evaluated to be in the range of 3.0–3.3 for isothermal crystallization. The subsequent melting endotherms of the blends after isothermal crystallization showed multiple melting peaks. The crystallization activation energies of the blends with 20 or 40% PTT was −48.3 and −60.9 kJ/mol, respectively, as calculated by the Arrhenius formula for the isothermal‐crystallization processes. The Hoffman–Lauritzen theory was also employed to fit the process of isothermal crystallization, and the kinetic parameters of the blends with 20 or 40% PTT were determined to be 1.5 × 105 and 1.8 × 105 K2, respectively. The spherulite morphology of the six binary blends formed at 190°C showed different sizes and perfect Maltese crosses when the PTT or PEN component was varied, suggesting that the greater the PTT content was, the larger or more perfect the crystallites were that formed in the binary blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3316–3325, 2007
Thermal and mechanical properties of uncrosslinked and chemically crosslinked polyethylene/ethylene vinyl acetate copolymer blends
Authors: Khonakdar H. A. , Jafari S. H. , Haghighi‐Asl A. , Wagenknecht U. , Häussler L. , Reuter U. 
Published: December 2006

AbstractUncrosslinked and chemically crosslinked binary blends of low‐ and high‐density polyethylene (PE), with ethylene vinyl acetate copolymer (EVA), were prepared by a melt‐mixing process using 0–3 wt % tert‐butyl cumyl peroxide (BCUP). The uncrosslinked blends revealed two distinct unchanged melting peaks corresponding to the individual components of the blends, but with a reduced overall degree of crystallinity. The crosslinking further reduced crystallinity, but enhanced compatibility between EVA and polyethylene, with LDPE being more compatible than HDPE. Blended with 20 wt % EVA, the EVA melting peak was almost disappeared after the addition of BCUP, and only the corresponding PE melting point was observed at a lowered temperature. But blended with 40% EVA, two peaks still existed with a slight shift toward lower temperatures. Changes of mechanical properties with blending ratio, crosslinking, and temperature had been dominated by the extent of crystallinity, crosslinking degree, and morphology of the blend. A good correlation was observed between elongation‐at‐break and morphological properties. The blends with higher level of compatibility showed less deviation from the additive rule of mixtures. The deviation became more pronounced for HDPE/EVA blends in the phase inversion region, while an opposite trend was observed for LDPE/EVA blends with co‐continuous morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3261–3270, 2007
Effect of annealing on fracture behavior of poly(propylene‐block‐ethylene) using essential work of fracture analysis
Authors: Li Qing‐guo , Xie Bang‐Hu , Yang Wei , Li Zhong‐Ming , Zhang Wei‐qin , Yang Ming‐Bo 
Published: December 2006

AbstractThe influence of annealing conditions on the fracture behavior of poly(propylene‐block‐ethylene) sheets was investigated by means of the essential work of fracture method, and was complemented by the study of the effect of annealing on crystal structure, using differential scanning calorimetry. It was shown that both the crystal perfection degree and crystallinity could be improved substantially as annealing temperature (Ta) increased, while the prolonged annealing time at 80°C mainly resulted in the improvement of crystallinity. The reasons for an increase in the specific essential work of fracture and a decrease in the specific plastic work item as crystal perfection degree and crystallinity grew are discussed. The displacement to failure of double edge notched tension specimens decreased gradually with increasing Ta, and the double‐plastic zone could be observed in all specimens. In addition, a novel method to aid the accurate measurement of intense stress‐whitening outer plastic zone height by adjustment of illumination conditions is proposed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3438–3446, 2007
Poly(N‐isopropylacrylamide‐co‐sodium acrylate) hydrogels: Interactions with surfactants
Authors: Mohan Y. M. , Joseph D. K. , Geckeler K. E. 
Published: December 2006

AbstractPoly(N‐isopropylacrylamide‐co‐sodium acrylate) [poly(NIPAM‐co‐SA)] hydrogels were modified with three different kind of surfactants (cationic, anionic, and nonionic) to study the effect on the swelling properties. The structural variation of the surfactant‐modified hydrogels was investigated in detail. The interaction between the surfactants and the hydrogel varies and strictly depends on the surfactant type. The variation in thermal stability of the modified surfactant hydrogels was investigated and compared with unmodified hydrogel. Further, the hydrogel swelling/diffusion kinetic parameters were investigated and diffusion of water into hydrogel was found to be of the non‐Fickian transport mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3423–3430, 2007
Control of structure and mechanical properties for binary blends of poly(3‐hydroxybutyrate) and cellulose derivative
Authors: Yamaguchi Masayuki , Arakawa Keiichi 
Published: December 2006

AbstractStructure and mechanical properties for binary blends composed of a poly(3‐hydroxybutyrate) (PHB) and a cellulose derivative, such as cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB), have been studied by means of dynamic mechanical analysis, isothermal crystallization measurements, and tensile testing. It is found that β relaxation temperature due to glass transition of PHB or PHB‐rich phase in the blends, in which the cellulose derivative has lower molecular weight, is almost the same as that of the pure PHB. On the other hand, the peak location is shifted to even lower temperature than that of the pure PHB by blending the cellulose derivative with higher molecular weight, although the cellulose derivative is a glassy polymer with high glass transition temperature. Further, the blend with lower β relaxation temperature exhibits ductile behavior with low modulus in uniaxial deformation. The difference in the structure and mechanical properties for the blends are found to be determined by the crystallization rate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3447–3452, 2007
Effect of the surface roughness and construction material on wall slip in the flow of concentrated suspensions
Authors: Gulmus Sergul Acikalin , Yilmazer Ulku 
Published: December 2006

AbstractRecent studies on polyethylene, elastomers, and thermoplastics have revealed that the construction material and surface roughness are two important factors affecting wall slip. In this study, to determine the true rheological behavior of model concentrated suspensions, a multiple‐gap separation method was used in a parallel disk rheometer. The model suspensions studied were poly (methyl methacrylate) particles with an average particle size of 121.2 μm in hydroxyl‐terminated polybutadiene. The aim of this study was to investigate the effect of disk Ra in the range of 0.49–1.51 μm and disk construction material on the wall slip and the true viscosity of the model concentrated suspensions. The wall slip velocity and the viscosity were found to be independent of Ra for particle size‐to‐disk Ra ratios of 80–247. Also, the true viscosity was found not to be affected by the rheometer surface construction material. Glass surfaces resulted in the highest slip velocity, whereas aluminum surfaces resulted in the lowest slip velocity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3341–3347, 2007