bluuebunny/crossref_metadata_2025_split huggingface dataset:
A critical study on the removal of copper by an electrochemically assisted coagulation: equilibrium, kinetics, and thermodynamics
Authors: Vasudevan Subramanyan , Lakshmi Jothinathan , Kamaraj Ramakrishnan , Sozhan Ganapathy 
Published: May 2012

ABSTRACTThe present paper provides an electrocoagulation process for the removal of copper from water through electrochemically generated Zn2+ using zinc as the anode and galvanized iron as the cathode. The different operating parameters on the removal efficiency of copper were investigated, such as initial copper ion concentration, initial pH, current density, and temperature. The results showed that the optimum removal efficiency of 96.6% was achieved at a current density of 0.05 A dm−2, at pH of 7.0. The effect of co‐existing anions such as arsenate, phosphate, boron, and fluoride were studied on the removal efficiency of copper. The results of pilot scale study show that the process was technologically feasible. The adsorption of copper, preferably fitting the Langmuir adsorption isotherm, suggests monolayer coverage of adsorbed molecules. First and second‐order rate equations, Elovich, and intraparticle diffusion models were applied to study adsorption kinetics. The adsorption process follows second‐order kinetics model with good correlation. Temperature studies showed that adsorption was endothermic and spontaneous in nature. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Titanium and iron dissolutions from ilmenite by acid leaching and microbiological oxidation techniques
Authors: Jonglertjunya Woranart , Rubcumintara Theeraporn 
Published: May 2012

ABSTRACTThis research was concerned with the solubility of ilmenite (Tin Tailing) in acids (sulfuric, hydrochloric, oxalic and citric) and bioleaching by Aspergillus niger, Penicillium citrinum and Bacillus megaterium. Ilmenite concentrate was soluble in 1.5 M sulfuric acid and 1.5 M hydrochloric acid solutions at 90 °C. However, improved leaching was obtained with 8 and 12 M sulfuric acid solutions. The chemical leaching results for different stirring speeds showed that a speed of 750 rpm was favourable to iron and titanium dissolutions. Metal dissolution rate can be enhanced with increasing leaching time. The optimum percentages of iron and titanium extraction occurred at 750 rpm for 6 h leaching in 8 M sulfuric acid solution and amounted to 64 and 57%, respectively. However, the optimum condition of chemical extraction was 1 M citric acid, which is considered weak, 750 rpm for 20 h extraction time at 90 °C. This led to the maximum titanium concentration of 63% that was comparatively very high compared with low iron dissolution of only 11%. Spores of A. niger and P. citrinum solutions were individually transferred at the culture ratio of 1 : 0, 0 : 1 and 1 : 1 in a shake flask containing Sabouraud dextrose medium. The flasks were incubated in a rotary shaker at 30 °C and 200 rpm. The bioleaching experiments after 35 days gave the highest iron extraction of 0.45% in the presence of pure culture (A. niger) and mixed culture (A. niger and P. citrinum), whereas the titanium dissolution was observed to be very low (<0.28% extraction). For the bioleaching, B. megaterium was subcultured in solution in a shake flask containing nutrient broth. The flasks were incubated in a rotary shaker at 30 °C and 200 rpm. The bioleaching experiments after 3 days gave the highest iron and titanium extraction of 0.2 and 0.4%, respectively. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Diffusion coefficients of water in biobased hydrogel polymer matrices by nuclear magnetic resonance imaging
Authors: Doll Kenneth M. , Vermillion Karl E. , Fanta George F. , Liu Zengshe 
Published: May 2012

AbstractThe diffusion coefficients of water in biobased hydrogels were measured with a simple NMR method. This method tracked the migration of deuterium oxide through imaging data that was fit to a diffusion equation. The results show that a 5 wt % soybean‐oil‐based hydrogel gave an aqueous diffusion of 1.37 (±0.21) × 10−9m2/s. The value for a 0.5 wt % saponified starch–polyacrylonitrile graft copolymer was 1.28 (±0.26) × 10−9m2/s, which remained about the same at increased polymer content in the hydrogel. For comparison, a commercially available acrylic polymer was evaluated with the same methodology and was found to have a diffusion coefficient of 7.6 (±1.3) × 10−10m2/s, about half that of the biobased products studied here. These parameters are of significant interest in the development of controlled release applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012
Effects of the processing temperature on the nanostructure and mechanical properties of PCTG‐based nanocomposites
Authors: Granado A. , Eguiazábal J. I. , Nazábal J. 
Published: May 2012

AbstractThe influence of the processing temperature on both the dispersion level and the mechanical properties of the amorphous copolyester (PCTG)/organoclay (Cloisite® 20A) nanocomposite (NC) is studied in this article. At high processing temperatures, no change in the chemical nature of the matrix was observed, but its molecular weight decreased. Widely dispersed structures were observed by wide angle X‐ray diffraction (WAXD) and transmission electron microscopy whatever the processing temperature might be. Dispersion was greatest for the samples processed at 200°C due to the highest viscosity of these samples and decreased at higher processing temperatures (Tp). These different dispersion levels led to a large modulus increase (71%) after processing at 200°C and to lower ones (about 50%) after processing at 230 and 260°C. The ductility of the NCs decreased at lower processing temperatures. The decrease was attributed to the greater stiffness of the matrix, and was not significant enough to modify the ductile nature of the NCs, which showed clear yield points even at the lowest processing temperature (200°C). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Evaluation of strongly acidic ion‐exchange catalysts and the desulfonation study in the isobutylene dimerization reaction
Authors: Tan Songwei , Yuan Fang , Zhao Dan , Wang Hongjun , Tu Kehua , Tsao Wilbert , Wang Li‐Qun 
Published: May 2012

AbstractThree commercial ion‐exchange resin based catalysts were compared under different temperature and liquid‐volume hourly space velocity (LHSV) in the isobutene (IB, C4) dimerization reaction using a plug flow reactor in the absence of any selectivity enhancing component. High IB conversion for all catalysts was obtained at or higher than 50°C. But, diisobutene (DIB, C8) selectivity decreased with the increase of temperature. High C8 selectivity was observed with LHSV higher than 1.5 at 50°C. The best catalytic performance of the three resins did not show obvious differences. The effect of the selectivity enhancers on the stability of the resins was also studied. Desulfonation was observed in the C4 dimerization reaction when water or the commonly used enhancer tert‐butyl alcohol (TBA) was added to the feed. The deactivation of catalyst resulted in decrease of both IB conversion and C8 selectivity. Fourier Transform Infrared spectroscopy showed that desulfonation happened in both para and ortho positions of the sulfonated benzene rings. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Optimization of the property profile of poly‐L‐lactide by synthesis of PLLA‐polystyrene–block copolymers
Authors: Dorff Giselher , Hahn Mathias , Laschewsky André , Lieske Antje 
Published: May 2012

AbstractDiblock and triblock copolymers of poly‐L‐lactide (PLLA) and polystyrene (PS) were synthesized and the mechanical properties of these copolymers studied. Free radical polymerization of styrene in the presence of 2‐mercaptoethanol as functional chain transfer agent produced mono‐functionalized PS‐blocks which were used as macroinitiators in the subsequent ring opening polymerization (ROP) ofL‐lactide to produce the diblock copolymers. Furthermore a α‐ω‐bishydroxyl functionalized PS‐block was synthesized by RAFT, which was then engaged as bifunctional initiator for the ROP ofL‐lactide to provide the triblock copolymers PLLA‐PS‐PLLA. Through the copolymerisation and high molar masses, it was possible to achieve an improved mechanical property profile, compared with pure PLLA, or the analogous blends of PLLA and PS. A weight fraction of PS of 10–30% was found to be the optimal range for improving the heat deflection temperature (HDT), as well as mechanical properties such as ultimate tensile strength or elongation at break. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Monophosphorylation of cornstarch to improve its sizing properties for heat‐sensitive wool yarns at reduced temperature
Authors: Zhu Zhifeng , Liu Zhijun , Li Manli , Xu Desheng , Li Changlong 
Published: May 2012

AbstractCommercial cornstarch was mono‐phosphorylated to different levels of substitution in order to investigate the effect of phosphorylation on the properties of cornstarch for sizing heat‐sensitive wool yarns at reduced temperature. The influences of starch phosphorylation and sizing temperature upon apparent viscosity and viscosity stability of cooked starch paste, starch retrogradation, adhesion to wool fibers, performance of starch film, aerobic biodegradation, mechanical properties, and hairiness of sized wool yarns were evaluated. The phosphorylation level was varied from 0.021 to 0.082 in degree of substitution (DS), while the temperature considered was from 60 to 95°C. It was found that mono‐phosphorylation of starch resulted in enhanced paste stability, reduced retrogradation, strong adhesion to wool fibers, increased performances of starch film, improved mechanical properties of sized wool yarns, and decreased hairiness on surface of sized yarns even if paste temperature was lowered to 60°C. Initially increasing phosphorylation level enhanced positive effects, but excessively increasing the level was not applicable due to marked reduction in tensile strength of starch film. The phosphorylation with a DS value of 0.061 could improve the performances of cornstarch for sizing wool yarns at 60–80°C. Moreover, measurement on BOD5/COD ratios demonstrated that the phosphorylation did not impede aerobic biodegradation of starch. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Improvement of compatibility of poly(ethylene terephthalate) and poly(ethylene octene) blends by γ‐irradiation
Authors: Yin Yuan , Liu Meihua , Zheng Xiaowei , Shen Shirley Zhiqi , Deng Pengyang 
Published: May 2012

AbstractBlends of poly(ethylene terephthalate) (PET) and poly(ethylene octene) (POE) were prepared by melt blending with various amounts of trimethylolpropane triacylate (TMPTA). The mechanical properties, phase morphologies, and gel fractions at various absorbed doses of γ‐irradiation have been investigated. It was found that the toughness of blends was enhanced effectively after irradiation as well as the tensile properties. The elongation at break for all studied PET/POE blends (POE being up to 15 wt %) with 2 wt % TMPTA reached 250–400% at most absorbed doses of γ‐irradiation, approximately 50–80 times of those of untreated PET/POE blends. The impact strength of PET/POE (85/15 wt/wt) blends with 2 wt % TMPTA irradiated with as little as 30 kGy absorbed dose exceeded 17 kJ/m2, being approximately 3.4 times of those of untreated blends. The improvement of the mechanical properties was supported by the morphology changes. Scanning electron microscope images of fracture surfaces showed a smaller dispersed phase and more indistinct inter‐phase boundaries in the irradiated blends. This indicates increased compatibility of PET and POE in the PET/POE blends. The changes of the morphologies and the enhancement of the mechanical properties were ascribed to the enhanced inter‐phase boundaries by the formation of complex graft structures confirmed by the results of the gelation extraction and Fourier Transform Infrared analyses. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of fiber treatment on the water absorption and mechanical properties of hemp fiber/polyethylene composites
Authors: Fang Haixia , Zhang Yaolin , Deng James , Rodrigue Denis 
Published: May 2012

AbstractThe hemp fiber/polyethylene (PE) composites were prepared by varying the fiber shape (hemp flour and hemp fiber from thermomechanical refining), coupling agent (maleic anhydride grafted and copolymerized onto PE), coupling agent loading method (during fiber treating process in the thermomechanical refiner and compositing process in twin screw extruder), and compositing method (twin screw extruding and batch mixing). The paper firstly measured the moisture absorption properties of the treated fibers. The introduction of coupling agent during fiber treating process decreased effectively the moisture uptake. Then, the water absorption and mechanical properties were investigated on the hemp/PE composites. The loading of coupling agent during fiber treating process decreased the water uptake but also decreased the flexural yield strength, consequently resulted in lower flexural yield strength after water exposure. The composites prepared by batch mixing method were better than by twin screw extruding for the water resistance and mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Kinetic study of the dehydrogenation reaction in polyacrylonitrile‐based carbon fiber precursors during thermal stabilization
Authors: Xue Yan , Liu Jie , Liang Jieying 
Published: May 2012

AbstractThe kinetics of dehydrogenation reaction and the structural evolution in polyacrylonitrile precursor fibers during thermal stabilization in air have been studied by Fourier transform infrared spectroscopy. The results indicate that, with the progress of dehydrogenation, the absorbance of methylene groups (CH2) gradually decreases, whereas that of methine groups (CH) gradually increases. The dehydrogenation reaction in the fibers is basically completed after 20‐min stabilization above 255°C. According to the Beer–Lambert law, the values of the absorbance for both CH2 groups and the resulting CH groups have been calculated and converted into the concentration fractions of CH2 groups via the Lorentzian multipeak fitting. According to the principles of chemical kinetics, the dehydrogenation reaction has been determined as a pseudo‐second‐order reaction with an activation energy of 107.6 kJ mol−1. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Spectroscopic and thermal characterization of the swelling behavior of nafion membranes in mixtures of water and methanol
Authors: Martinez‐Felipe A. , Imrie C. T. , Ribes‐Greus A. 
Published: May 2012

AbstractThe spectroscopic and thermal properties of swollen Nafion membranes in methanol aqueous mixtures were investigated to understand the behavior of commercial electrolytes in the presence of polar solvents. Several differences were observed in the absorption processes depending on the composition of the solvent. Deconvolution methods were applied to study specific contributions of solvents and polymer groups based on Fourier transform infrared spectroscopy and thermogravimetric analysis. The results evidence compositional effects on the interactions between solvents and Nafion. A major influence of the nonpolar domains (hydrophobic regions) in the absorption of methanol together with a reduction of the interactions with sulfonate groups was observed. Such changes are accompanied by a modification of the cluster morphology of the equilibrated membranes evaluated by differential scanning calorimetry. These findings can be useful to improve the knowledge on Nafion's microstructure in the presence of polar solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and gas transport properties of novel hyperbranched polyimide–silica hybrid membranes
Authors: Suzuki Tomoyuki , Yamada Yasuharu 
Published: May 2012

AbstractPhysical and gas transport properties of hyperbranched polyimide (HBPI)—silica hybrid membranes prepared with a dianhydride monomer, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and triamine monomers, 1,3,5‐tris(4‐aminophenoxy)triazine (TAPOTZ), and 1,3,5‐tris(4‐aminophenyl)benzene (TAPB), were investigated and compared with those of 6FDA‐TAPOB HBPI system synthesized from 6FDA and 1,3,5‐tris(4‐aminophenoxy)benzene (TAPOB). Glass transition and 5% weight‐loss temperatures of the 6FDA‐based HBPI–silica hybrid membranes were increased with increasing silica content. 6FDA‐TAPOTZ HBPI system, however, showed relatively low 5% weight‐loss temperatures, suggesting thermal instability of triazine‐ring in the TAPOTZ moiety. CO2/CH4 permselectivity of the HBPI–silica hybrid membranes were increased with increasing silica content, tending to exceed the upper bound for CO2/CH4 separation. This result indicated that free volume elements effective for CO2/CH4 separation were created by the incorporation of silica for the HBPI–silica hybrid systems. Especially, 6FDA‐TAPB HBPI system had high gas permeabilities and CO2/CH4 separation ability, arising from high fractional free volume and characteristic size and distribution of free volume elements. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Aliphatic polycarbonate‐based polyurethane elastomers and nanocomposites. II. Mechanical, thermal, and gas transport properties
Authors: Poręba Rafał , Špírková Milena , Brožová Libuše , Lazić Nada , Pavličević Jelena , Strachota Adam 
Published: May 2012

AbstractThermal, thermomechanical, tensile and gas transport properties of aliphatic polycarbonate‐based polyurethanes (PC‐PUs) and their nanocomposites with bentonite for organic systems were studied. Hard segments are formed from hexamethylene diisocyanate and butane‐1,4‐diol. All PC‐PUs and their nanocomposites feature high degree of the phase separation. Three phase transitions were detected by temperature‐modulated differential scanning calorimetry (TMDSC) and dynamic mechanical thermal analysis. TMDSC revealed the filler affinity both to soft and hard segments, even though the affinity to hard segments is much stronger. Elongation‐at‐break at ambient temperatures is mostly over 700%, which leads together with high tensile strength (in some cases) to very high toughness values (over 200 mJ/mm3). The addition of 1 wt % of bentonite does not practically affect mechanical properties implying its very good incorporation into the PU matrix. Permeabilities and other gas transport properties depend on regularity of PC‐diol and on hard segment content, but the variations are insignificant. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of all para‐position polysulfonamide fiber
Authors: Li Humin , Zhu Yin , Xu Bing , Wu Chengxun , Zhao Jiongxin , Dai Mingxin 
Published: May 2012

AbstractPoly(4,4′‐diphenylsulfone terephthalamide) referred to as all para‐position polysulfonamide (all para‐position PSA) is a special kind of PSAs, copolymers of 3,3′‐diaminodiphenylsulfone, 4,4′‐diaminodiphenylsulfone, and terephthaloyl chloride. However, with the increasing para‐structure content in the PSAs, the PSA shows very poor solubility in common amide‐type polar aprotic solvents and cannot be used for wet spinning. In this article, it was found that all para‐position PSA can be easily dissolved in N,N‐Dimethylacetamide (DMAc)/LiCl system, and then the all para‐position PSA fiber was prepared for the first time by wet spinning. The properties of all para‐position PSA pulps and fibers were investigated via Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy, thermal gravimetric analysis, dynamical mechanical analysis, X‐ray diffraction (XRD), and tensile strength testing. The tensile strength, elongation at break, and crystallinity of the resulting fiber were 4.4 cN/dtex, 15.9%, and 33.53%, respectively. The results indicated that all para‐position PSA fiber was a high‐temperature resistance fiber with better mechanical properties than common PSA fiber. The improved tensile strength of the fiber will expand its applications and may take place of Nomex in certain fields and become a new generation of flame retardant and high‐temperature resistant material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Recycling of PET waste using 3‐amino‐1‐propanol by conventional or microwave irradiation and synthesis of bis‐oxazin there from
Authors: Shah Rikhil V. , Borude Vasant S. , Shukla Sanjeev R. 
Published: May 2012

AbstractThere is a growing interest in recycling of post‐consumer poly(ethylene terephthalate) (PET) waste for both environmental and economic reasons. PET in the form of disposable soft drink bottle waste was subjected to depolymerization via aminolysis using excess of 3‐amino‐1‐propanol under soxhlet by conventional heating as well as microwave irradiation using catalyst sodium acetate or potassium sulfate. The product obtained was characterized after purification by using melting point, IR spectroscopy, nuclear magnetic resonance, and differential scanning calorimeter and was found to be bis‐(3‐hydroxy propyl) terephthalamide (BHPTA). The BHPTA thus obtained was subjected to cyclization reaction using thionyl chloride to obtain bis‐oxazin under conditions of ambient temperature. Bis‐oxazin has applications in polymer synthesis as a chain extender or a cross linking agent. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Robust superhydrophilic coatings by electropolymerization of sulfonated pyrrole
Authors: Canterbury Daniel P. , Huang Kun , Xie Tao , Rzayev Javid 
Published: May 2012

AbstractSuperhydrophilic coatings were prepared by electropolymerization of sufonated pyrrole from aqueous solutions. The monomer was prepared in one step from commercially available reagents. Electropolymerized polymer films exhibited significant surface roughness and porosity as evidenced by scanning electron microscopy analysis. Advancing water contact angles of the pristine coatings were as low as 12°, while receding angles were 0° for almost all samples. Soaking the films in hot water resulted in decrease in the advanced contact angles to as low as 0°. The produced coatings retained their extreme wetting characteristics even when treated in harsh environments, such as dry heat for a week. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012
Singapore's anatomical future: Quo Vadis?
Authors: Ang Eng‐Tat , Sugand Kapil , Hartman Mikael , Seow Choon‐Sheong , Bay Boon‐Huat , Abrahams Peter 
Published: May 2012

AbstractThe disciplines of anatomy and surgery are not dichotomous since one is dependent on the other. Traditionally, surgeons predominantly taught gross and clinical anatomy. In this review, we examine the context of how human anatomy is taught nowadays. In essence, we discovered that there are certain discernable trends consistently observable between the American and British systems. In Singapore, the British Russell Group first influenced its education landscape but now more so by the American Ivy League. Singapore now has three medical schools all offering differing anatomy curricula, which serves as an opportune time for it to consider if there is a best approach given that the practice of surgery is also evolving in parallel. This review discusses the various pedagogies and issues involved, and will serve as a forum and stimulus for discussion. By tweaking the curriculum correctly and the lessons learnt, future doctors and surgeons in training will receive a better anatomical education, not just in Singapore but the world in general. Key recommendations include the use of body painting, clay, plasticine to facilitate the learning of anatomy, and the implementation of a body donation program. Furthermore, strategic mergers with key stakeholders will also ensure the survival of the discipline. Anat Sci Educ. © 2012 American Association of Anatomists.