bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melt‐processed biodegradable polyester blends of poly(L‐lactic acid) and poly(ε‐caprolactone): Effects of processing conditions on biodegradation
Authors: Tsuji Hideto , Horikawa Gen , Itsuno Shinichi 
Published: January 2007

AbstractBiodegradable polyester blends were prepared from poly(L‐lactic acid) (PLLA) and poly(ε‐caprolactone) (PCL) (50/50) by melt‐blending, and the effects of processing conditions (shear rate, time, and strain) of melt‐blending on proteinase‐K‐ and lipase‐catalyzed enzymatic degradability were investigated using gravimetry, differential scanning calorimetry, and scanning electron microscopy. The proteinase‐K‐catalyzed degradation rate of the blend films increased and leveled off with increasing the shear rate, time, or strain for melt‐blending, except for the shortest shear time of 60 s. The optimal processing conditions of melt‐blending giving the maximum rate of lipase‐catalyzed degradation were 9.6 × 102 s−1 and 180 s, whereas a deviation from these conditions caused a reduction in lipase‐catalyzed enzymatic degradation rate. At the highest shear rate of 2.2 × 103 s−1, PCL‐rich phase was continuous in the blend films, irrespective of the shear time (or shear strain), whereas PLLA‐rich phase changed from dispersed to continuous by increasing the shear time (or shear strain). This study revealed that the biodegradability of PLLA/PCL blend materials can be manipulated by altering the processing conditions of melt‐blending (shear rate, time, or strain) or the sizes and morphology of PLLA‐rich and PCL‐rich domains. The method reported in the present study can be utilized for controlling the biodegradability of other biodegradable polyester blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 831–841, 2007
Relaxation time and conductivity of comb‐like gel polymer electrolytes
Authors: Qi Li , Dong Shaojun 
Published: January 2007

AbstractUsing the copolymer of acrylonitrile (AN), methyl methacrylate (MMA), and poly(ethylene glycol) methyl ether methacrylate as a backbone and poly(ethylene glycol) methyl ether (PEGME) with 1100 molecular weight as side chains, comb‐like gel polymers and their Li salt complexes were synthesized. The dynamic mechanical properties and conductivities were investigated. Results showed that the gel copolymer electrolytes possess two glass transitions: α‐transition and β‐transition. Based on the time–temperature equivalence principle, a master curve was constructed by selecting Tα as reference temperature. By reference to T0 = 50°C, the relation between log τc and c was found to be linear. The master curves are displaced progressively to higher frequencies as the content of plasticizer is increased. The relation between log τp and the content of plasticizer is also linear. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 576–584, 2007
Effect of nonconjugated polymers on the conjugation length and structure of poly(3‐octylthiophene) in ternary polymer blend
Authors: Huang Ying‐Jie , Hsieh Tar‐Hwa , Wang Yen‐Zen , Chuang Ching‐Nan , Chen Ya‐Ping , Huang Ping‐Tsung , Ho Ko‐Shan 
Published: January 2007

AbstractThe shifting of λmax (π‐π* transition) of P3OT (poly(3‐n‐octylthiophene)) was used to monitor the degree of miscibility between P3OT and the matrix polymers. In the ternary blend system, 1% of P3OT is soluble in a uniform PMMA/EVA20 mixed matrix and does not interfere with the miscibility between PMMA and EVA20 (ethylene‐vinyl acetate copolymer with 20% of vinyl acetate). But 5% of P3OT can attract EVA20 out of the matrix and induce the separation from 95% of PMMA/EVA20 matrix and cause the doublet peak of λmax. Likewise, the DSC thermograms do not demonstrate the melting‐point depression of EVA20 in a 5% P3OT ternary system. However, the melting‐point depression did occur only for 1% of P3OT. IR‐spectra demonstrate that the methylene groups affinity contributed to the misciblity either in 1% P3OT/PMMA or in P3OT (1 and 5%)/EVA20. The solubility difference of P3OT in PMMA (poor) and EVA20 (better) creates a continuous morphology for obtaining a highly conjugated path in a nonconjugated matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 773–781, 2007
Graft copolymerization of styrene or methyl methacrylate onto syndiotactic polystyrene by ATRP technique
Authors: Abbasian Mojtaba , Rahmani Sohrab , Mohammadi Reza , Entezami Ali Akbar 
Published: January 2007

AbstractFunctionalized syndiotactic polystyrene (sPS) copolymers, including sPS‐graft‐atactic polystyrene (aPS) copolymer or sPS‐graft‐poly(methyl methacrylate) (PMMA) copolymer, were synthesized and characterized. sPS has been synthesized by using half sandwich titanocene/methylaluminoxane catalyst in homogenous conditions. Then, α‐phenyl chloroacetylation of sPS was accomplished in a heterogeneous process by using carbon disulfide as dispersing medium and α‐phenyl chloroacetyl chloride and anhydrous aluminum chloride as acetylating agent and catalyst, respectively. The graft copolymer of sPS with aPS or PMMA were synthesized by atom transfer radical polymerization using α‐phenyl chloroacethylated sPS as initiator and CuBr and bipyridine as catalyst. The structure of obtained copolymer was investigated by 1H NMR, FTIR spectroscopy, and thermal behavior of copolymers was performed by differential scanning calorimetry analyses. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 611–619, 2007
Processable and colorless fluorinated poly(ether imide)s based on an isopropylidene‐containing bis(ether anhydride) and various aromatic bis(ether amine)s bearing trifluoromethyl groups
Authors: Huang Sheng‐Yu , Yang Chin‐Ping , Hsiao Sheng‐Huei 
Published: January 2007

AbstractA series of novel organosoluble and light‐colored fluorinated poly(ether imide)s (PEIs) (IV) having inherent viscosities of 0.43–0.59 dL/g were prepared from 4,4′‐[1,4‐phenylenbis(isopropylidene‐1,4‐phenyleneoxy)]diphthalic anhydride (I) and various trifluoromethyl‐substituted aromatic bis(ether amine)s by a standard two‐step process with thermal and chemical imidization of poly(amic acid) precursors. These PEIs showed excellent solubility in many organic solvents and could be solution‐cast into transparent and tough films. These films were essentially colorless, with an UV–visible absorption edge of 361–375 nm and a very low b* value (a yellowness index) of 15.3–17.0. They also showed good thermal stability with glass‐transition temperature of 191–248°C, 10% weight loss temperature in excess of 494°C, and char yields at 800°C in nitrogen more than 39%. The thermally cured PEI films showed good mechanical properties with tensile strengths of 83–96 MPa, elongations at break of 8–11%, and initial moduli of 1.7–2.0 GPa. They possessed lower dielectric constants of 3.25–3.72 (1 MHz). In comparison with the V series nonfluorinated PEIs, the IV series showed better solubility, lower color intensity, and lower dielectric constants. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 620–628, 2007
Blends of triazine‐based hyperbranched polyether with LDPE and plasticized PVC
Authors: Borah Jyotishmoy , Karak Niranjan 
Published: January 2007

AbstractTriazine‐based hyperbranched polyether was obtained by earlier reported method and blended with low density polyethylene (LDPE) and plasticized poly(vinyl chloride) (PVC) separately to improve some desirable properties of those linear polymers. The properties like processability, mechanical properties, flammability, etc. of those linear polymers were studied by blending with 1–7.5 phr of hyperbranched polyether. The mechanical properties were also measured after thermal aging and leaching in different chemical media. SEM study indicates that both polymers exhibit homogenous morphology at all dose levels. The mechanical properties like tensile strength, elongation at break, hardness, etc. of LDPE and PVC increase with the increase of dose level of hyperbranched polyether. The flame retardant behavior as measured by limiting oxygen index (LOI) for all blends indicates an enhanced LOI value compared to the polymer without hyperbranched polyether. The processing behavior of both types of blends as measured by solution viscosity and melt flow rate value indicates that hyperbranched polyether acts as a process aid for those base polymers. The effect of leaching and heat aging of these linear polymers on the mechanical properties showed that hyperbranched polyether is a superior antidegradant compared to the commercially used N‐isopropyl‐N‐phenyl p‐phenylene diamine. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 648–654, 2007
Comparison of the growth process and electrochemical properties of polyaniline films prepared by pulse potentiostatic and potentiostatic method on titanium electrode
Authors: Zhou H. H. , Wen J. B. , Ning X. H. , Fu C. P. , Chen J. H. , Kuang Y. F. 
Published: January 2007

AbstractPolyaniline (PANI) films were deposited on titanium (Ti) electrode in a bath containing 0.3 mol L−1 aniline and 1 mol L−1 HNO3 by pulse potentiostatic method (PPM) and potentiostatic method (PM). The chronoamperograms during aniline polymerization were recorded, and the morphologies of PANI films prepared with different polymerization periods were examined under scanning electron microscope. The difference between the processes of PANI films growth was studied. The growth processes of PANI films prepared by PPM and PM are divided into two stages. For both PPM and PM, the first stage corresponds to the formation of a compact granular PANI layer on the surface of Ti electrode. The second stage corresponds to further growth of PANI film on the surface of the compact granular PANI film. However, the PANI films prepared by PPM and PM show different morphologies in this stage. In addition, the electrochemical properties of the PANI films prepared by PPM and PM are obviously different. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 458–463, 2007
User modeling for personalized Web search with self‐organizing map
Authors: Ding Chen , Patra Jagdish C. 
Published: January 2007

AbstractThe widely used Web search engines index and recommend individual Web pages in response to a few keywords queries to assist users in locating relevant documents. However, the Web search engines give different users the same answer set, although the users may have different preferences. A personalized Web search would carry out the search for each user according to his or her preferences. To conduct the personalized Web search, the authors provide a novel approach to model the user profile with a self‐organizing map (SOM). Their results indicate that SOM is capable of helping the user to find the related category for each query used in the Web search to make a personalized Web search effective.
Kinetic modeling of phototrophic biofilms: The PHOBIA model
Authors: Wolf Gundula , Picioreanu Cristian , van Loosdrecht Mark C.M. 
Published: January 2007

AbstractA kinetic model for mixed phototrophic biofilms is introduced, which focuses on the interactions between photoautotrophic, heterotrophic, and chemoautotrophic (nitrifying) functional microbial groups. Biofilm‐specific phenomena are taken into account, such as extracellular polymeric substances (EPS) production by phototrophs as well as gradients of substrates and light in the biofilm. Acid–base equilibria, in particular carbon speciation, are explicitly accounted for, allowing for the determination of pH profiles across the biofilm. Further to previous models reported in literature, the PHOBIA model combines a number of kinetic mechanisms specific to phototrophic microbial communities, such as internal polyglucose storage under dynamic light conditions, phototrophic growth in the darkness using internally stored reserves, photoadaptation and photoinhibition, preference for ammonia over nitrate as N‐source and the ability to utilize bicarbonate as a carbon source in the absence of CO2. The sensitivity of the PHOBIA model to a number of key parameters is analyzed. An example on the potential use of phototrophic biofilms in wastewater polishing is discussed, where their performance is compared with conventional algal ponds. The PHOBIA model is presented in a manner that is compatible with other reference models in the area of water treatment. Its current version forms a theoretical base which is readily extendable once further experimental observations become available. Biotechnol. Bioeng. 2007; 97: 1064–1079. © 2007 Wiley Periodicals, Inc.
Enhanced preparation of adeno‐associated viral vectors by using high hydrostatic pressure to selectively inactivate helper adenovirus
Authors: Leonard Joshua N. , Ferstl Peter , Delgado Antonio , Schaffer David V. 
Published: January 2007

AbstractGene delivery vectors based on adeno‐associated virus (AAV) have significant therapeutic potential, but much room for improvement remains in the areas of vector engineering and production. AAV production requires complementation with either helper virus, such as adenovirus, or plasmids containing helper genes, and helper virus‐based approaches have distinct advantages in the use of bioreactors to produce large quantities of AAV vectors for clinical applications. However, helper viruses must eventually be inactivated and removed from AAV preparations to ensure safety. The current practice of thermally inactivating adenovirus is problematic as it can also inactivate AAV. Here, we report a novel method using high hydrostatic pressure (HHP) to selectively and completely inactivate helper adenovirus without any detectable loss of functional AAV vectors. The pressure inactivation kinetics of human adenovirus serotype 5 and the high‐pressure stabilities of AAV serotypes 2 and 5 (AAV2, AAV5), which were previously unknown, were characterized. Adenovirus was inactivated beyond detection at 260 MPa or higher, whereas AAV2 was stable up to ∼450 MPa, and surprisingly, AAV5 was stable up to at least 700 MPa. The viral genomic DNA of pressure‐inactivated AAV2 was made sensitive to DNAse I digestion, suggesting that gross changes in particle structure had occurred, and this hypothesis was further supported by transmission electron microscopy. This approach should be useful in the laboratory‐ and clinical‐scale production of AAV gene delivery vectors. Moreover, HHP provides a tool for probing the biophysical properties of AAV, which may facilitate understanding and improving the functions of this important virus. Biotechnol. Bioeng. 2007; 97: 1170–1179. © 2007 Wiley Periodicals, Inc.
Effects of Operational Variables on Nitrogen Removal Performances and Its Control in a Pre‐Denitrification Plant
Authors: Wang X. L. , Peng Y. Z. , Ma Y. , Wang S. Y. 
Published: January 2007

AbstractThe aim of this work is to study the effects of six operational variables, i.e., dissolved oxygen (DO), nitrate recirculation flow, sludge recycle flow, sludge wastage flow, external carbon dosage, and anoxic volume fraction, on the performance of nitrogen removal and its control in a pre‐denitrification plant. The results obtained show that the six operational variables have a significant influence on nitrogen removal in such a system, while the utilization of the control strategies can improve the situation to a significant extent. The control of DO concentration should be correlated with the influent ammonia load, the effluent requirement and nitrification type. The anoxic effluent nitrate concentration should be controlled at ca. 2 mg/L or the ORP value at the end of the anoxic zone should be controlled at ca. –90 mV. The control of the sludge recycling flow by online monitoring of the sludge blanket height (SBH), is an alternative to the conventional control of the constant sludge recycle flow. It may be possible to achieve the automatic control of sludge wastage flow by online measuring of the ammonia concentration and the nitrification capacity of the sludge. The recirculation of nitrate and external carbon dosage should be simultaneously controlled to optimize nitrogen removal. The anoxic volume fraction should also be optimized, to ensure a good balance between nitrification and denitrification.
Modeling of the Seedless Grape Drying Process using the Generalized Differential Quadrature Method
Authors: Esmaiili M. , Rezazadeh G. , Sotudeh‐Gharebagh R. , Tahmasebi A. 
Published: January 2007

AbstractMathematical modeling of the grape drying process is important in understanding the transport phenomena involved in the production and processing of dried grapes. Drying models proposed in the literature have simplifying assumptions, and thus ignore important phenomena such as shrinkage and changes in transport properties which occur during the drying process. Consequently, a mathematical model is developed for the seedless grape drying process, which considers the effects neglected in previous models. Since an analytic solution to this nonlinear model is impossible, the generalized differential quadrature method is used to solve the models' equations. The model is validated with experimental data obtained from a laboratory scale convective tray dryer operating at 50–70 °C and an air velocity of 1.5 m/s. Model predictions are in close agreement with experimental data due to the inclusion in the model of shrinkage and variation in moisture diffusivity. Model results can serve as a framework to improve the performance of existing and novel dryers, and also in the design of process simulators for dryers.
Triboelectrostatic Separation of Fly Ash with Different Charging Materials
Authors: Soong Y. , Irdi G. A. , McLendon T. R. , Hedges S. W. , Dilmor R. M. , Griffith C. , Romanov V. , Haljasmaa I. 
Published: January 2007

AbstractA combination of mechanical sieving and triboelectrostatic separation were used to separate fly ash. The results indicate that a simple separation of unburned carbon from fly ash is achievable at particle sizes of 74 and 44 microns. Subsequently, triboelectrostatic separations were conducted via a louvered plate separator. The results show that the final carbon content in the products, which can be as low as 1.5 % or as high as 60 % with different mineral components, can be further adjusted with the combination of sieving, louvered plate separator with a tribocharger made of different materials (copper and Teflon), and the location on the louvered plate where the fly ash particles were collected.
Noncatalytic Hydrolysis of Iminodiacetonitrile in Near‐Critical Water – A Green Process for the Manufacture of Iminodiacetic Acid
Authors: Duan P.‐G. , Wang X. , Dai L.‐Y. 
Published: January 2007

AbstractThe hydrolysis of iminodiacetonitrile (IDAN) in near‐critical water, without added catalysts, has been successfully conducted with temperature and residence time ranges of 200–260 °C and 10–60 min, respectively. The effects of temperature, pressure, and initial reactant/water ratio on the reaction rate and yield have been investigated. The final reaction products primarily included iminodiacetic acid (IDA) and ammonia associated with other by‐products; gas formation was negligible. The maximum yield of IDA was 92.3 mol.‐% at 210 °C and 10 MPa, with a conversion of almost 100 %.The apparent activation energy and ln A of IDAN hydrolysis were evaluated as 45.77 ± 5.26 kJ/mol and 8.6 ± 0.1 min–1, respectively, based on the assumption of first‐order reaction. The reaction mechanism and scheme were similar to those of base‐catalyzed reactions of nitriles examined in less severe conditions.
Technology Optimization of Wet Flue Gas Desulfurization Process
Authors: Hrastel I. , Gerbec M. , Stergaršek A. 
Published: January 2007

AbstractOptimization of the wet limestone (calcite) flue gas desulfurization (FGD) process is described, with the focus on the layout of subprocesses and equipment. The aim of optimization was to check the effectiveness and reliability of alternative layouts, involving intermediate product (gypsum) storage in the absorber make‐up tank, instant production of limestone slurry from powder in a wet screw conveyer and automatic gypsum dewatering line operation. Three alternatives, standard layout, optimized layout and optimized layout without reheating of treated gas, were designed and tested in a small industrial FGD plant. The comparison included evaluation of desulfurization efficiency, economical feasibility (considering a 125 MW power plant) and reliability of operation. The efficiency of the system was not affected by the layouts. Investment costs were reduced by 5 and 15 % for alternatives 1 and 2, respectively, compared to standard offers on the market. With respect to operating costs, variable operating and maintenance costs could be decreased by 0.5 up to 2.5 %, respectively. As shown by risk and reliability analysis, the availability of the system in both alternative layouts remained unchanged or was better with regard to the standard layout.
Determination of Liquid Radial Spreading Coefficients of Some Highly Effective Packings
Authors: Dzhonova‐Atanasova D. , Kolev N. , Nakov S. 
Published: January 2007

AbstractThe liquid radial spreading coefficient of packings for absorption and rectification columns is necessary to determine the packing height which ensures uniform liquid distribution over the column cross section. The existing calculation methods can be used theoretically only when this coefficient is independent of the liquid superficial velocity, which is often not the case. A tracer method free from this limitation is developed and tested. The spreading coefficients for different sizes of modern, highly effective packings (Raschig Super‐Ring, Ralu‐Flow, and impulse metal tower packing) are determined. Practically, in the range of the experimental error, the spreading coefficients of these packings are independent of the liquid superficial velocity. For such packings the tracer method is expected to give the same results as the existing single jet method. Some differences between the results of these two methods are discussed and an explanation is proposed.
Effects of Ionic Environments on Bovine Serum Albumin Fouling in a Cross‐Flow Ultrafiltration System
Authors: Salgın S. 
Published: January 2007

AbstractThe influence of electrostatic interactions on membrane fouling during the separation of bovine serum albumin (BSA) from solution was studied in a cross‐flow ultrafiltration system. Experiments were carried out at different pH values between 3.78 and 7.46; and for different ionic strengths between 0.001 M and 0.1 M. The changes in permeate flux, cake layer resistance, zeta potentials of BSA and polyether sulfone (PES) membranes, and electrostatic interaction energies, were evaluated. At all of the ionic conditions studied, PES membranes are negatively charged. However, BSA molecules are either negatively or positively charged depending on the ionic environment. Whereas the cake layer resistance decreased with increasing pH and ionic strength, the permeate fluxes increased. The calculated electrostatic energy was a minimum at the isoelectric point (IEP) of BSA. However, at this point, the cake resistances corresponding to fouling at each ionic strength, were not minimized. Below the IEP of BSA, the electrostatic forces were attractive, while above the IEP, repulsive electrostatic forces were dominant.
Protonenaustauschmembranen durch strahlungsinduzierte Pfropfpolymerisation von Glycidylmethacrylat auf ETFE – Modifizierung mit Butylacrylat und Acrylnitril
Authors: Schmidt C. , Glück T. , Schmidt‐Naake G. 
Published: January 2007

AbstractDie Suche nach Alternativen zum meist verwendeten Nafion® für polymere Protonenaustauschmembranen in Wasserstoff‐Brennstoffzellen ist seit Jahren Gegenstand zahlreicher Forschungsaktivitäten. Diese Arbeit stellt Systeme auf Basis von Poly(tetraflourethylen‐alt‐ethylen) (ETFE) vor, das über die einfache und vielseitige strahlungsinduzierte Pfropfpolymerisation mit Glycidylmethacrylat gepfropft und durch Sulfonierung in Austauschmembranen überführt wird. Im Vordergrund steht dabei die Modifizierung dieser Systeme durch Copolymerisation mit Butylacrylat und Acrylnitril und die Charakterisierung der Materialien in Hinblick auf mechanische und thermische Stabilität, Wasseraufnahme und Ionenleitfähigkeit.