bluuebunny/crossref_metadata_2025_split huggingface dataset:
Particle injection into a chain: decoherence versus relaxation for Hermitian and non‐Hermitian dynamics
Authors: Gebhard F. , zu Münster K. , Ren J. , Sedlmayr N. , Sirker J. , Ziebarth B. 
Published: February 2012

AbstractA model system for the injection of fermionic particles from filled source sites into an empty chain is investigated. The ensuing dynamics for Hermitian as well as for non‐Hermitian time evolution, where the particles cannot return to the bath sites (quantum ratchet), is studied. A non‐homogeneous hybridization between bath and chain sites permits transient currents in the chain. Non‐interacting particles show decoherence in the thermodynamic limit: the average particle number and the average current density in the chain become stationary for long times, whereas the single‐particle density matrix displays large fluctuations around its mean value. Using the numerical time‐dependent density‐matrix renormalization group (t‐DMRG) method it is demonstrated, on the other hand, that sizable density‐density interactions between the particles introduce relaxation which is by orders of magnitudes faster than the decoherence processes.
Rotational quantum impurities in a metal: Stability of the 2‐channel Kondo fixed point in a magnetic field
Authors: Ballmann K. , Kroha J. 
Published: February 2012

AbstractA three‐level system with partially broken SU(3) symmetry immersed in a metal, comprised of a unique non‐interacting ground state and two‐fold degenerate excited states, exhibits a stable two‐channel Kondo fixed point within a wide range of parameters, as has been shown in previous work. Such systems can, for instance, be realized by protons dissolved in a metal and bound in the interstitial space of the host lattice, where the degeneracy of excited rotational states is guaranteed by the space inversion symmetry of the lattice. We analyze the robustness of the 2CK fixed point with respect to a level splitting of the excited states and discuss how this may explain the behavior of the well‐known dI/dV spectra measured by Ralph and Buhrman on ultrasmall quantum point contacts in a magnetic field.
Potential use of oil palm sap on lactic acid production and product adsorption on Dowex™ 66 resin as adsorbent
Authors: Chooklin Supasit , Kaewsichan Lupong , Kaewsrichan Jasadee 
Published: February 2012

ABSTRACTLactic acid is a product that finds several applications in food, cosmetic, pharmaceutical, and chemical industries. The main objective of this work is to evaluate potential use of the oil palm (Elaeis guineensis) sap as a substrate by Lactobacillus casei. The effects of pH control and nutrient supplement of oil palm sap on fermentation performance were investigated. In this report, when oil palm sap was used as a carbon source for L. casei, pH control did not significantly affect lactic acid production. The addition of de Man, Rogosa, and Sharpe medium improved the biomass and the product yield for which the lactic acid production in static flask at 37 °C and pH 5.5 using 20 g L−1 of total sugar was improved to 0.55 g L−1 h−1. Oil palm sap could serve as a good potential source of raw materials for efficient production of lactic acid by L. casei. When lactic acid was separated from the fermentation broth with Dowex™ 66 resin by water as eluant, the desorption yield was 75.16%. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Membrane treatment of oily wastewater from refinery processes
Authors: Madaeni S. S. , Gheshlaghi A. , Rekabdar F. 
Published: February 2012

ABSTRACTOily wastewater is produced in oil refining processes. This waste is usually treated by a number of physical, chemical, and biological techniques in water treatment units of oil refinery before being disposed in environment or reused as agricultural water. One of the treatment techniques for oil separation from wastewater is membrane filtration. This paper presents the performances of hydrophilic microfiltration (MF GRM) and ultrafiltration (UF GRM) polymeric membranes challenged with synthetic feed (gas oil dispersed in water) and oily wastewater effluent of American Petroleum Institute unit in refinery. A comparison was carried out under optimum conditions and in cross‐flow mode in laboratory scale. The effects of operating parameters (i.e. pressure and cross‐flow velocity) on flux and rejection were elucidated. The flux of MF GRM membrane for real feed within the first 2 h of filtration was low compared with synthetic feed because of the presence of solid and colloidal particles in the real feed. The oil rejection (around 99%) for synthetic feed was higher compared with real feed. Similar trend was found for both UF GRM and MF GRM membranes. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Adaptive soft sensors using local partial least squares with moving window approach
Authors: Liu Jialin , Chen Ding‐Sou , Lee Ming‐Wei 
Published: February 2012

ABSTRACTDeveloping soft sensors for an industrial process, the colinearity of the predictor variables and the time‐varying nature of the process need to be concerned. In many industrial applications, the partial least square (PLS) has been proven to be able to capture the linear relationship between input and output variables for a local operating region; therefore, the PLS model needs to be adapted to accommodate the time‐varying nature of the process. In this paper, a fast‐moving window algorithm is derived to update the PLS model. The proposed approach adapted the parameters of the inferential model with the dissimilarities between the new and oldest data and incorporated them into the kernel algorithm for the PLS. The computational loading of the model adaptation was therefore independent of the window size. Because a moving window approach is sensitive to outliers, the confidence intervals for the primary variables were created on the basis of the prediction uncertainty. The inferential model would not be misled by the outliers from the online analyzers, whereas the model could be updated during the transition stage. An industrial example, predicting oxygen concentrations in the air separation process, demonstrated the effectiveness of the proposed approach for the process industry. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Design and evaluation of aspirin‐loaded water‐in‐oil‐in‐water submicron multiple emulsions generated using two‐stage ultrasonic cavitational emulsification technique
Authors: Tang Siah Ying , Sivakumar Manickam 
Published: February 2012

ABSTRACTThe main goal of the present work was to develop a novel aspirin containing water‐in‐oil‐in‐water (W/O/W)‐type submicron multiple emulsions via two‐stage ultrasound cavitational emulsification using Span 80 and Cremophor EL as lipophilic and hydrophilic emulsifiers for the formation of primary and secondary emulsions, respectively. Effect of the following parameters, i.e. concentration of emulsifiers, ultrasonic amplitude and second sonication period on the mean droplet diameter, polydispersity index, droplet size stability and drug entrapment efficiency was studied. The osmotic behavior of the ultrasonically prepared multiple emulsions was also studied with different glucose concentrations in the inner and outer aqueous phases. The presence of gelatin played an important role in preventing interdroplet coalescence via formation of interfacial rigid film. Core shell type of multiple droplets with mean droplet diameter of around 400 nm was produced using 1.25% w/w Span 80 and 0.5% w/w Cremophor EL. The experimental results have shown that the long‐term stability of the W/O/W multiple emulsions is significantly improved with the addition of both 0.5% w/w of glucose and 1% w/w of gelatin in the inner phase. This investigation has clearly proved that the use of ultrasound cavitation is an efficient yet promising approach in the generation of stable and uniform submicron multiple emulsions of aspirin. Copyright © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Synthesis, characterization, and study of antibacterial activity of homopolymers and copolymers of 4‐benzyloxyphenylacrylates for pressure‐sensitive adhesive application
Authors: Mageswari S. , Subramanian K. 
Published: February 2012

AbstractPoly(4‐benzyloxyphenylacrylate) and its copolymers with glycidyl methacrylate were synthesized from the monomer, 4‐benzyloxyphenylacrylate (4‐BOPA) by free radical solution polymerization. The synthesized homopolymers and copolymers were characterized by UV, FTIR, 1H‐NMR, and 13C‐NMR spectroscopic techniques. The thermal stability of the polymers was performed by thermogravimetric analysis in inert atmosphere. The glass transition temperatures of the polymers were determined by differential scanning calorimeter. The lap shear strength of the polymers was determined by Universal testing machine. The antibacterial activities of the polymers were also studied by UV spectroscopy. The results of the TGA analysis showed that the polymers possess good stability even beyond 250°C. Different concentrations of the polymer solutions were prepared and tested for their adhesive strength by applying them between leather strips. Thus, the results of the study reveal that the poly(4‐benzyloxyphenylacrylate‐co‐glycidyl methacrylate) has good adhesive strength compared with poly(4‐BOPA), which can be used for its adhesive property suitable for high temperature applications, which can also resist the bacterial growth on the applied surface of the material. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Facile and efficient route for preparation of polypyrrole‐ZnO nanocomposites: Microstructural, optical, and charge transport properties
Authors: Chougule M. A. , Sen S. , Patil V. B. 
Published: February 2012

AbstractPolypyrrole (PPy) nanocomposites reinforced with zinc oxide (ZnONPs) nanoparticles are fabricated by spin coating method. The polymer nanocomposite films were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), UV‐vis spectroscopy and two probe technique. The results were compared with PPy film. Powder XRD analysis demonstrates the crystalline structure of ZnO nanostructures, as well as their corresponding nanocomposites. The SEM images of the nanocomposites show uniform distribution of the ZnO NPs in the PPy matrix. The overall grain size was found to change in nanocomposite films. In the FTIR spectra, the characteristic peaks of pure PPy are observed to shift to higher wave number revels the different interfacial interactions between the ZnO NPs and the PPy matrix. In the UV‐vis spectra, absorption peak of PPy shifts to lower wavelengths indicating poor conjugation. The electrical resistivity of PPy‐ZnO nanocomposites is observed to depend strongly on the particle loadings and the morphology. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Influence of the morphology on the fire behavior of a polycarbonate/poly(butylene terephthalate) blend
Authors: Sonnier Rodolphe , Viretto Amandine , Taguet Aurélie , Lopez‐Cuesta José‐Marie 
Published: February 2012

AbstractPolycarbonate/Poly(butylene terephthalate) (PC/PBT) blends are used in various industrial sectors, particularly in the cable industry. In this work, the fire behavior of PC/PBT blends was studied for the entire range of blend composition to investigate the relation between fire properties and blend morphology. The morphology of the binary blends used presents a phase inversion point for 25–30 wt % PBT. Various tests have been performed to characterize the fire behavior [limiting oxygen index (LOI), epiradiator test, cone calorimeter, and pyrolysis combustion flow calorimeter (PCFC)]. A change in fire behavior has been observed when the PBT content increases from 20 to 30 wt %, corresponding to the phase inversion, from a continuous rich‐PC phase to a continuous rich‐PBT phase. Consequently, it can be suggested that the control of the morphology of binary polymer blends is crucial to improve their fire properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study of lysozyme‐polymer composite microparticles in supercritical CO2
Authors: Chen Ai‐Zheng , Pu Xi‐Ming , Yin Guang‐Fu , Zhao Chen , Wang Shi‐Bin , Liu Yuan‐Gang , Wang Guang‐Ya , Kang Yong‐Qiang 
Published: February 2012

AbstractLysozyme‐loaded polymeric composite microparticles were successfully coprecipitated by solution‐enhanced dispersion by supercritical CO2 (SEDS), starting with a homogeneous organic solvent solution of lysozyme/poly(L‐lactide)/poly(ethylene glycol) (lysozyme/PLLA/PEG). The effects of different drug loads (5, 8, and 12% w/w), PLLA Mw (10, 50, 100, and 200 kDa), PEG contents (0, 10, 30, and 50% PEG/(PLLA+PEG) w/w), and PEG Mw (400, 1000, and 4000 kDa) on the surface morphology, particle size, and drug release profile of the resulting composite microparticles were investigated. The results indicate that the size of the microparticles decreased and the rate of drug release increased with an increase in drug load, PEG content, or PEG Mw; the particle size first increased and then decreased with an increase in PLLA Mw, and the drug release was controlled by both particle size and PLLA Mw. The Fourier transform infrared spectrometer analysis and circular dichroism spectra measurement reveal that no significant changes occurred in the molecular structures during the SEDS processing, which is favorable to the production of protein–polymer composite microparticles for a protein drug delivery system. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study of structural and thermal properties of electron beam irradiated polymethylmethacrylate/bisphenol‐A‐polycarbonate blends
Authors: Magida M. M. 
Published: February 2012

AbstractPolymethylmethacrylate (PMMA) and bisphenol‐A‐polycarbonate (PC) polymer blends are prepared by solution casting technique using tetrahydrofuran as a solvent. The structural properties of the polymer blends before and after they had been irradiated to electron beam accelerator was investigated by color strength, scanning electron microscopy (SEM), and FTIR spectroscopy. The thermal properties such as TGA and DSC were investigated. The TGA thermograms showed that the thermal stability of the unirradiated polymer blends PMMA/PC increases with increasing the ratios of PC component in the blend. Also, it was found that the presence of PC polymer in the blend affords protection against radiation degradation and improves their thermal stability. The DSC scans show a single Tg intermediate between PMMA and PC indicate the existence of specific interactions between PMMA and PC polymers in the blend. An intimate blends are reflected by substantial shifts in the frequencies of the PMMA and PC CO vibration obtained by FTIR. SEM confirms the homogeneity of the blend. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci 125:3184–3190, 2012
Influence of poly(ether imide) on the free volume hole size and distributions in poly(ether ether ketone)
Authors: Ramani R. , Alam S. 
Published: February 2012

AbstractBlends of poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI) were examined for their miscibility at the nanoscopic level using positron annihilation lifetime spectroscopy (PALS) and modulated differential scanning calorimetry (MDSC). The free volume results obtained from PALS reveal that PEEK and PEI exhibit high degree of miscibility showing interlamellar segregation when the PEI content in the blend is ≥50%. Although the average free volume sizes of PEEK and PEI are nearly same, a clear distinction could be made from their size distribution. The free volume of PEI is found to be narrow as compared with PEEK. Also, herein, we provide the first evidence of the influence of interlamellar segregation on the free volume distribution in a polymer blend. The crystalline structure of the blend was studied by X‐ray scattering and the surface morphology was examined by scanning electron microscopy (SEM). The MDSC results indicate the presence of a possible rigid amorphous fraction (RAF) and corroborate the positron lifetime and X‐ray scattering results. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The interfacial modification of rice straw fiber reinforced poly(butylene succinate) composites: Effect of aminosilane with different alkoxy groups
Authors: Zhao Yang , Qiu Jianhui , Feng Huixia , Zhang Min 
Published: February 2012

AbstractThe effect of aminosilane on the properties of rice straw fiber (RSF) reinforced poly(butylene succinate) (PBS) composites was studied. RSF was pretreated with four different aminosilane coupling agents, 3‐aminopropyltriethoxysilane (APTES), 3‐aminopropyltrimethoxysilane (APTMES), 3‐(2‐aminoethylaminopropyl)triethoxysilane (AEAPTES), and 3‐(2‐aminoethylaminopropyl)‐trimethoxysilane (AEAPTMES). The results of Fourier transform infrared spectroscopy (FTIR) and ζ potential measurements confirmed that amino groups were introduced to the silane‐treated RSF (TRSF) for all four silane coupling agents. The results also indicated a higher degree of hydroxyl ion adsorption by the fiber surface, which was chemically grafted by silane hydroxyl, was obtained with ethoxy silane than with methoxy silane. This difference might be because the relative rates of hydrolysis and ensuing silanol self‐condensation of methoxy silane were too fast to reduce the number of silanol groups grafted on the fiber surface. The TRSF composite produced clearly enhanced tensile properties for the aminosilane coupling agents having ethoxy groups. The AEAPTES‐RSF‐PBS composite showed the highest tensile strength. It might be because of the higher amino content of AEAPTES than APTES; the amino groups on the surface of TRSF were confirmed by FT‐IR to react with the carbonyl groups of PBS to form a blue‐shifted hydrogen bond. The water absorption process of composites was found to follow the kinetics and mechanisms described by Fick's theory. The aminosilane treatment significantly reduced the moisture diffusion coefficient but did not change the mechanism of water adsorption. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
ABA low molar mass triblock copolymers in reverse emulsions: A rheological study
Authors: Gonzalez Juan M. , Rodrigues Jorge de A. , Nascimento Regina S. V. 
Published: February 2012

AbstractThe effect of blocks length and molar mass of ABA triblock copolymers on the rheological behavior of water in oil (w/o) emulsions was investigated. Emulsion parameters such as water droplet concentration (and droplet size) of a series of inverted emulsion systems were evaluated. All copolymer/emulsion systems studied showed a non‐Newtonian behavior, and the presence of the copolymer in the emulsion system led to an increase of the low shear viscosity when the size of the midblock of the copolymer was in a specific size range. This suggests the formation of a transient network through the interconnection, by the copolymer, of the smaller water droplets present in the emulsion. Consequently, the systems behave as w/o emulsions containing reversibly crosslinked oil‐soluble polymers in the continuous phase, resulting in a pronounced shear thinning behavior. For the different emulsions studied, the relative viscosity increased, with few exceptions, with increasing droplet concentration. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Anomalous attenuation and structural origin of positive temperature coefficient (PTC) effect in a carbon black (CB)/poly(ethylene terephthalate) (PET)/polyethylene (PE) electrically conductive microfibrillar polymer composite with a preferential CB distribution
Authors: Dai Kun , Zhang Yi‐Chuan , Tang Jian‐Hua , Ji Xu , Li Zhong‐Ming 
Published: February 2012

AbstractThis article reports the positive temperature coefficient (PTC) and negative temperature coefficient (NTC) effects of a carbon black (CB)‐filled electrically conductive microfibrillar poly(ethylene terephthalate) (PET)/polyethylene (PE) composite (FCMC). The composite contains in situ polymer microfibrils in the matrix of another polymer with CB particles selectively localized at microfibrils' surfaces. Anomalous attenuations of PTC and NTC intensities (IPTC and INTC) of FCMC were observed during heating–cooling runs (HCRs) and long‐term isothermal treatments. Particularly, when the isothermal treatment time was 32 h, the IPTC decreased from 5.5 in the original sample to only 0.5, showing a tremendous attenuation ratio of up to 91%, and the NTC effect was completely eliminated. On the contrary, attenuations of PTC and NTC effects in a common conductive polymer composite (CCPC) were so weak as to be negligible through the same thermal treatments. Microstructural changes of the conductive network by Brownian motion and large size of the conductive component‐CB coated PET microfibrils are both responsible for the great reductions in IPTC and INTC. The present results strongly suggest that thermal field induced microstructural transformation by Brownian motion helps to reveal the origin of PTC and NTC effects. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Physicochemical characterization of lignin fractions sequentially isolated from bamboo (Dendrocalamus brandisii) with hot water and alkaline ethanol solution
Authors: Shi Zheng‐Jun , Xiao Ling‐Ping , Jia‐Deng  , Xu Feng , Sun Run‐Cang 
Published: February 2012

AbstractNine lignin fractions from bamboo (Dendrocalamus brandisii) were sequentially isolated with hot water at 80, 100, and 120°C for 3 h and 60% aqueous ethanol containing 0.25, 0.5, 1.0, 2.0, 3.0, and 5.0% NaOH at 80°C for 3 h. Molecular weight and purity analysis revealed that the lignin fractions isolated by hot water (L1, L2, and L3) had lower weight‐average molecular weights (between 1350 and 1490 g mol−1) and contained much higher amounts of associated hemicelluloses (between 9.26 and 22.29%), while the lignin fractions isolated by alkaline aqueous ethanol (L4, L5, L6, L7, L8, and L9) had higher weight‐average molecular weights (between 2830 and 3170 g mol−1) and contained lower amounts of associated hemicelluloses (between 0.63 and 1.66%). Spectroscopy (UV, FTIR, 13C‐NMR, and HSQC) analysis showed that the bamboo (Dendrocalamus brandisii) lignin was typical grass lignin, consisting of p‐hydroxyphenyl (H), guaiacyl (G), and syringyl (S) units. The major interunit linkages presented in the alkaline aqueous ethanol extractable bamboo lignin were β‐O‐4′ aryl ether linkages (about 74.3%), followed by β‐β′ resinol‐type linkages and β‐1′ spirodienone‐type linkages (both for 7.8%), together with small amounts of β‐5′ phenylcoumaran (6.8%) and p‐hydroxycinnamyl alcohols end groups (3.1%). In addition, a small percentage (1.0%) of the lignin side‐chain was found to be acetylated at the γ‐carbon, predominantly over syringyl units. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Behavior of semi IPN hydrogels composed of PEG and AAm/SMA copolymers in swelling and uptake of Janus Green B from aqueous solutions
Authors: Üzüm Ömer Barış , Karadağ Erdener 
Published: February 2012

AbstractSemi‐interpenetrating polymer network (semi IPN) hydrogels of poly(ethylene glycol; PEG) were prepared as a water adsorbent for dye (Janus Green B) sorption. For this, PEG and copolymer of acrylamide/sodium methacrylate (AAm/SMA) were prepared by polymerization of aqueous solution of acrylamide (AAm), sodium methacrylate (SMA) using ammonium persulfate (APS)/N,N,N′,N′‐tetramethylethylenediamine (TEMED) as redox initiating pair in presence of PEG and poly(ethylene glycol)dimethacrylate (PEGDMA) as crosslinker. FTIR spectroscopy was used to identify the presence of different repeating units in the semi IPNs. Some swelling and diffusion characteristics were calculated for different semi IPNs and hydrogels prepared under various formulations. Water uptake and dye sorption properties of AAm/SMA hydrogels and AAm/SMA/PEG semi IPNs were investigated as a function of chemical composition of the hydrogels. Janus Green B have used in sorption studies. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012