bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on recyclability of polyhydroxybutyrate‐co‐valerate bioplastic: Multiple melt processing and performance evaluations
Authors: Zaverl Matthew , Seydibeyoğlu M. Özgür , Misra Manjusri , Mohanty Amar 
Published: April 2012

AbstractRecyclability of the bioplastic polyhydroxybutyrate‐co‐valerate (PHBV) was studied with multiple melt processing (five cycles), with their performances evaluated. A batch of PHBV was processed with a twin screw extrusion followed by injection molding. This operation was repeated five times and samples were collected from each cycle for characterization. For each cycle, the mechanical properties were characterized with tensile, flexural, and impact testing, along with dynamic mechanical analysis. The results showed that the mechanical properties are maintained for four cycles; but in the fifth cycle, there was slight decrease in the properties. Gel permeation chromatography studies revealed that the molecular weight of the polymer does not decrease drastically; however, a drop was observed after third, fourth, and fifth cycle (8.7% decrease after third cycle, 13.5% decrease after fourth cycle, and 16.6% decrease after fifth cycle). The differential scanning calorimeter showed that the glass transition and melting temperatures did not change upon reprocessing, but the degree of crystallinity was reduced as a consequence of melt processing. The thermal gravimetric analysis showed that the onset value of thermal decomposition decreased very slightly. It was observed by Fourier transform infrared spectroscopy that the chemical structure of PHBV was maintained without any side chain reaction during processing. Scanning electron microscopy studies from the fractured surfaces of Cycles 1 and 5 confirmed that the uniformity of PHBV surfaces was maintained after five cycles, coinciding with the mechanical tests. The density measurements revealed that there was no change in the density of PHBV. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Modeling the strain dependence of torque harmonics as measured through large‐amplitude oscillatory shear rheometry
Authors: Leblanc Jean L. 
Published: April 2012

AbstractData describing the stress response to large‐amplitude oscillatory shear can be considered as the nonlinear viscoelastic signature of polymer materials. How such data can be fitted with an appropriate equation is a problem of prime importance because (1) it allows results gathered in a large strain window to be summarized in a small number of representative parameters and (2) it permits a physical significance to be sought for equation parameters. This article analyzes and discusses several mathematical relationships that were proposed in the literature to fit harmonics vs. strain data, and probes their relative merits with various sets of experimental results. A simple four‐parameter model is shown to encompass all the other approaches and to yield parameters that correctly describe not only material behavior in the linear‐to‐nonlinear transition region but also in the asymptotic high‐strain range. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Stress/strain development around a spherical inclusion in a polymeric matrix: The effects of particle and matrix mechanical characteristics and thermal expansivity difference
Authors: Hosseinpour Dariush , Berg John C. 
Published: April 2012

AbstractFor a spherical inclusion embedded in an infinite polymeric matrix, the Goodier Model, combined with thermal stress contribution, is applied to establish the stress/strain fields around a spherical particle in different particle/matrix combinations, including TiO2, alumina, silica, steel, polystyrene, and polyvinyl butyral particles embedded in a range of polymeric matrices. This approach provides the basis for examining the effects of different parameters such as Young's modulus and Poisson's ratio of the particle and matrix, and the thermal history of samples on the failure‐initiation criteria. An explanation is provided for divergent results obtained for very soft and elastic particles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Macromolecular design of novel sulfur‐containing copolyesters with promising mechanical properties
Authors: Gigli M. , Lotti N. , Gazzano M. , Finelli L. , Munari A. 
Published: April 2012

AbstractThe miscibility of poly(butylene succinate) (PBS)/poly(butylene thiodiglycolate) (PBTDG) blends was investigated by DSC technique. PBS and PBTDG were completely immiscible in as blended‐state, as evidenced by the presence of two Tgs at −34 and −48°C, respectively. The miscibility changes upon mixing at elevated temperature: the original two phases merged into a single one because of transesterification reactions. Poly(butylene succinate/thiodiglycolate) block copolymers, prepared by reactive blending of the parent homopolymers, were studied to investigate the effects of transesterification reactions on the molecular structure and solid‐state properties. 13C‐NMR analysis evidenced the formation of copolymers whose degree of randomness increased with mixing time. Thermal characterization results showed that all the samples were semicrystalline, with a soft rubbery amorphous phase and a rigid crystal phase whose amount decreased by introducing BTDG units into the PBS chain (20 ≤ χc ≤ 41). Lastly, the mechanical properties were found strictly related to crystallinity degree (χc), the random copolymer, exhibiting the lowest elastic modulus (E = 61 MPa) and the highest deformation at break (εb (%) = 713). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Structure and physical properties of gelatin fibers prepared by gel‐spinning in ethylene glycol
Authors: Midorikawa Takehiko , Lawal Olayide Samuel , Sasaki Yosiko , Fukae Ryohei 
Published: April 2012

AbstractGelatin fibers were produced by gel‐spinning using ethylene glycol as the solvent. Gelation conditions, drawing temperature, and draw ratio were studied. Physical properties of the fibers were characterized by mechanical tests, thermal analysis, X‐ray diffractometry, and scanning electron microscopy. The mechanical strength of the fibers increased with increased draw ratio. The gelatin fiber prepared by extrusion of the gelatin (15 wt %)/ethylene glycol into methanol at −20°C and drawn up to seven times its original length at 5°C had the highest tensile strength (405 MPa), a Young's modulus of 11 GPa, and a storage modulus of 7.9 GPa at 200°C. Remarkable differences were observed between the morphology of the undrawn and the drawn fibers. The results show that a gelatin fiber with very good mechanical properties can be prepared using ethylene glycol as the dispersion medium. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Using model organism Saccharomyces cerevisiae to evaluate the effects of ELF‐MF and RF‐EMF exposure on global gene expression
Authors: Chen Guangdi , Lu Deqiang , Chiang Huai , Leszczynski Dariusz , Xu Zhengping 
Published: April 2012

AbstractThe potential health hazard of exposure to electromagnetic fields (EMF) continues to cause public concern. However, the possibility of biological and health effects of exposure to EMF remains controversial and their biophysical mechanisms are unknown. In the present study, we used Saccharomyces cerevisiae to identify genes responding to extremely low frequency magnetic fields (ELF‐MF) and to radiofrequency EMF (RF‐EMF) exposures. The yeast cells were exposed for 6 h to either 0.4 mT 50 Hz ELF‐MF or 1800 MHz RF‐EMF at a specific absorption rate of 4.7 W/kg. Gene expression was analyzed by microarray screening and confirmed using real‐time reverse transcription‐polymerase chain reaction (RT‐PCR). We were unable to confirm microarray‐detected changes in three of the ELF‐MF responsive candidate genes using RT‐PCR (P > 0.05). On the other hand, out of the 40 potential RF‐EMF responsive genes, only the expressions of structural maintenance of chromosomes 3 (SMC3) and aquaporin 2 (AQY2 (m)) were confirmed, while three other genes, that is, halotolerance protein 9 (HAL9), yet another kinase 1 (YAK1) and one function‐unknown gene (open reading frame: YJL171C), showed opposite changes in expression compared to the microarray data (P < 0.05). In conclusion, the results of this study suggest that the yeast cells did not alter gene expression in response to 50 Hz ELF‐MF and that the response to RF‐EMF is limited to only a very small number of genes. The possible biological consequences of the gene expression changes induced by RF‐EMF await further investigation. Bioelectromagnetics 33:550–560, 2012. © 2012 Wiley Periodicals, Inc.
Manufacture of Granular Polysilicon from Trichlorosilane in a Fluidized‐Bed Reactor
Authors: Wang C. J. , Wang T. F. , Wang Z. W. 
Published: April 2012

AbstractManufacturing of polysilicon by chemical vapor deposition from SiHCl3 in a fluidized‐bed reactor was studied. The effects of reaction temperature, H2/SiHCl3 ratio, gas velocity, and seed particle loading were evaluated. The outlet gas composition was analyzed by gas chromatography. The physical features of the product particles were determined by scanning electron microscopy and laser particle size analyzer. Well‐grown product particles were obtained. The temperature and H2/SiHCl3 ratio significantly affected conversion, yield, and selectivity, which were less affected by gas velocity and seed particle loading at higher temperatures. The surface reaction kinetics determined the product yield only at lower temperatures, and thermodynamic equilibrium was approached at temperatures above 900 °C.
ChemInform Abstract: Photooxidation of Coordinated Dinitrogen, Photolysis of the ClO2 Adduct of [(NH3)5Os(μ‐N2)Os (NH3)5]5+.
Authors: Vogler Arnd , Kunkely Horst 
Published: April 2012

AbstractFor the first time oxidative splitting of coordinated dinitrogen is achieved photochemically.
ChemInform Abstract: Tetrahydroisoquinoline‐Based N‐Oxides as Chiral Organocatalysts for the Asymmetric Allylation of Aldehydes.
Authors: Naicker Tricia , Arvidsson Per I. , Kruger Hendrik G. , Maguire Glenn E. M. , Govender Thavendran 
Published: April 2012

AbstractNovel Lewis base N‐oxide organocatalysts possessing tetrahydroisoquinoline as a readily tunable backbone are synthesized and evaluated in asymmetric allylation reactions of aromatic and α,β‐unsaturated aldehydes.
ChemInform Abstract: Facile Synthesis of Dihaloheterocycles via Electrophilic Iodocyclization.
Authors: Yang Fan , Jin Tienan , Bao Ming , Yamamoto Yoshinori 
Published: April 2012

AbstractThe present new and efficient iodocyclization of a wide range of substituted propargyl alcohols bearing ‐OH, ‐NTs, and ‐SAc functional groups at C4‐position with molecular iodine or bromoiodine affords the corresponding 3,4‐dihalodihydrofurans, ‐pyrroles, and ‐thiophenes in good yields.
ChemInform Abstract: Selective Oxidation of Unsaturated Alcohols Catalyzed by Sodium Nitrite and 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone with Molecular Oxygen under Mild Conditions.
Authors: Wang Lianyue , Li Jun , Yang Hua , Lv Ying , Gao Shuang 
Published: April 2012

AbstractThe procedure allows a simple and efficient access to conjugated aldehydes and ketones.
ChemInform Abstract: Reversing the Reactivity of Carbonyl Functions with Phosphonium Salts: Enantioselective Total Synthesis of (+)‐Centrolobine.
Authors: Fujioka Hiromichi , Yahata Kenzo , Kubo Ozora , Sawama Yoshinari , Hamada Tomohito , Maegawa Tomohiro 
Published: April 2012

AbstractInitial selective masking of the aldehyde function in ketoaldehydes with PPh3 and TmsOTf permits the selective reduction of the keto function or its alkylation with Grignard reagents followed by deprotection.
ChemInform Abstract: One‐Pot Ester Synthesis from Allyl and Benzyl Halides and Alcohols by Palladium‐Catalyzed Carbonylation
Authors: Tommasi Sara , Perrone Serena , Rosato Francesca , Salomone Antonio , Troisi Luiginio 
Published: April 2012

AbstractA mild and efficient synthesis of esters is presented.
ChemInform Abstract: Electrochemically Supported Deoxygenation of Epoxides into Alkenes in Aqueous Solution.
Authors: Huang Jing‐Mei , Lin Zhi‐Quan , Chen Dong‐Song 
Published: April 2012

AbstractThe reaction proceeds in an undivided cell fitted with a pair of zinc electrodes by building up a zinc nanostructure on the electrode surface.
ChemInform Abstract: One‐Pot Near‐Ambient Temperature Syntheses of Aryl(difluoroenol) Derivatives from Trifluoroethanol.
Authors: Kyne Sara H. , Percy Jonathan M. , Pullin Robert D. C. , Redmond Joanna M. , Wilson Peter G. 
Published: April 2012

AbstractThe development of a dehydrofluorination/zincation and Negishi coupling protocol is presented.
ChemInform Abstract: Efficient Palladium‐Catalyzed Amination of Aryl Chlorides Using Di(dicyclohexylamino)phenylphosphine as a PN2 Ligand.
Authors: Kim Bo Ram , Cho Su‐Dong , Kim Eun Jung , Lee In‐Hye , Sung Gi Hyeong , Kim Jeum‐Jong , Lee Sang‐Gyeong , Yoon Yong‐Jin 
Published: April 2012

AbstractA new, efficient ligand for the Pd‐catalyzed amination of aryl chlorides is found.
ChemInform Abstract: Construction of 1,2,5‐Tricarbonyl Compounds Using Methyl Cyanoacetate as a Glyoxylate Anion Synthon Combined with Copper(I) Iodide‐Catalyzed Aerobic Oxidation.
Authors: Kim Se Hee , Kim Ko Hoon , Kim Jae Nyoung 
Published: April 2012

AbstractA variety of α‐cyano‐δ‐ketocarboxylates (I) and (III), obtained by conjugate addition of cyanoacetate towards α,β‐unsaturated ketones, is efficiently oxidized to the corresponding α,δ‐diketo esters (II) and (IV), respectively.
ChemInform Abstract: Enantioselective Reaction of Imines and Benzyl Nitriles Using Palladium Pincer Complexes with C2‐Symmetric Chiral Bis(imidazoline)s.
Authors: Hyodo Kengo , Nakamura Shuichi , Tsuji Kotaro , Ogawa Takahiro , Funahashi Yasuhiro , Shibata Norio 
Published: April 2012

AbstractA variety of aromatic imines (I) reacts with diverse benzyl nitriles (II) and (VII) in the presence of a novel Pd pincer complex to afford the corresponding β‐amino nitriles (III) and (VIII), resp., in moderate to good diastereo‐ and enantioselectivities (up to 92% e.e.).
ChemInform Abstract: Synthesis of Sulfonyl Chlorides and Sulfonic Acids in SDS Micelles.
Authors: Bahrami Kiumars , Khodaei Mohammad M. , Abbasi Jamshid 
Published: April 2012

AbstractThe selective oxidation of different sulfides (or the analogous disulfides) is efficiently achieved with a combination of H2O2 and POCl3 in optimized ratios.
ChemInform Abstract: Room‐Temperature C—H Arylation: Merger of Pd‐Catalyzed C—H Functionalization and Visible‐Light Photocatalysis.
Authors: Kalyani Dipannita , McMurtrey Kate B. , Neufeldt Sharon R. , Sanford Melanie S. 
Published: April 2012

AbstractIn the presence of Pd and Ru catalysts, benzenes bearing heterocyclic or oxime units are found to undergo new and mild ortho‐arylation.
ChemInform Abstract: Abnormal N‐Heterocyclic Carbene Palladium Complex: Living Catalyst for Activation of Aryl Chlorides in Suzuki—Miyaura Cross‐Coupling.
Authors: Sau Samaresh Chandra , Santra Subhankar , Sen Tamal K. , Mandal Swadhin K. , Koley Debasis 
Published: April 2012

AbstractThe catalyst remains active for 10 successive cycles.
ChemInform Abstract: Dihydroxylation‐Based Approach for the Asymmetric Syntheses of Hydroxy‐γ‐butyrolactones.
Authors: Peed Jennifer , Davies Iwan R. , Peacock Lucy R. , Taylor James E. , Kociok‐Koehn Gabriele , Bull Steven D. 
Published: April 2012

AbstractTreatment of unsaturated amides of type (I), (IV), and (IX) with NMO/OsO4 leads to triols which spontaneously undergo cyclization to afford biologically important optically active hydroxy‐γ‐butyrolactones.
ChemInform Abstract: Palladium‐Catalyzed Oxidative Arylalkylation of Activated Alkenes: Dual C—H Bond Cleavage of an Arene and Acetonitrile.
Authors: Wu Tao , Mu Xin , Liu Guosheng 
Published: April 2012

AbstractA novel process is discovered to provide cyanoethyl‐substituted indolones in moderate to good yields.
ChemInform Abstract: Chiral Broensted Acid Catalyzed Stereoselective Addition of Azlactones to 3‐Vinylindoles for Facile Access to Enantioenriched Tryptophan Derivatives.
Authors: Terada Masahiro , Moriya Kenichi , Kanomata Kyohei , Sorimachi Keiichi 
Published: April 2012

AbstractA chiral BINAP‐derived phosphoric acid is demonstrated to be an efficient catalyst for the formation of title compounds with adjacent quaternary and tertiary stereogenic centers after alkaline methanolysis.
ChemInform Abstract: The Use of Glucose as Alternative Reducing Agent in Copper‐Catalyzed Alkyne—Azide Cycloaddition.
Authors: Garcia Marco A. , Rios Zita G. , Gonzalez Jaime , Perez Victor M. , Lara Nancy , Fuentes Aydee , Gonzalez Carlos , Corona David , Cuevas‐Yanez Erick 
Published: April 2012

AbstractAn inexpensive method for the synthesis of 1,2,3‐triazoles uses a catalytic system prepared from Fehling reagent and glucose.
ChemInform Abstract: Selective Synthesis of Fused 1,4‐ and 1,2‐Dihydropyridines by Domino Reactions of Arylamines, Acetylenedicarboxylate, Aldehydes, and Cyclic 1,3‐Diketones.
Authors: Sun Jing , Sun Yan , Gao Hong , Yan Chao‐Guo 
Published: April 2012

AbstractDomino reaction of arylamines (II) and (VI) with acetylenedicarboxylate (I), cyclic β‐dicarbonyl compounds (III) and (VII) and aromatic aldehydes (IV) provides access towards fused 1,4‐dihydropyridine derivatives (V) and (VIII) in moderate yields.
ChemInform Abstract: An Efficient Access to 2,3‐Diarylimidazo[1,2‐a]pyridines via Imidazo[1,2‐a]pyridin‐2‐yl Triflate Through a Suzuki Cross‐Coupling Reaction‐Direct Arylation Sequence.
Authors: Marhadour Sophie , Bazin Marc‐Antoine , Marchand Pascal 
Published: April 2012

AbstractA straightforward strategy for the synthesis of title compounds via Suzuki coupling of triflates or analogous halides followed by a direct C‐H arylation is developed.
ChemInform Abstract: Lewis Acid‐Catalyzed Selective Synthesis of Diversely Substituted Indolo‐ and Pyrrolo[1,2‐a]quinoxalines and Quinoxalinones by Modified Pictet—Spengler Reaction.
Authors: Verma Akhilesh K. , Jha Rajeev R. , Sankar V. Kasi , Aggarwal Trapti , Singh Rajendra P. , Chandra Ramesh 
Published: April 2012

AbstractLewis acid‐catalyzed reaction of N‐(o‐aminophenyl)pyrrole (I) with various aromatic aldehydes in short reaction time (1‐2h) proceeds by a modified Pictet—Spengler reaction to give dihydropyrroloquinoxalines (III).
ChemInform Abstract: An Efficient Metal‐Free Synthesis of 2‐(Pyrazin‐2‐yl)benzimidazoles from Quinoxalinones and Diaminomaleonitrile via a Novel Rearrangement.
Authors: Mamedov Vakhid A. , Zhukova Nataliya A. , Beschastnova Tat'yana N. , Zakirova El'vira I. , Kadyrova Saniya F. , Mironova Ekaterina V. , Nikonova Anna G. , Latypov Shamil K. , Litvinov Igor A. 
Published: April 2012

AbstractAn interesting synthesis of title compounds is achieved by acid‐promoted rearrangement of intermediates (III) or (VI), readily prepared by reaction of acyl‐ substituted quinoxalinones with diaminomalononitrile.
ChemInform Abstract: Efficient Synthesis of Piperazinediones Using Potassium Iodide Catalysis in Aqueous Media.
Authors: Wen Yong‐Hong , Chen Xiao‐Na , Wen Hui‐Ling , Tang Xiao‐Fang 
Published: April 2012

AbstractA mild, inexpensive, and environmentally friendly synthesis of the title compounds (II) is developed.
ChemInform Abstract: An Efficient One‐Step Synthesis of Piperidin‐2‐yl and Pyrrolidin‐2‐yl Flavonoid Alkaloids Through Phenolic Mannich Reactions.
Authors: Nguyen Thanh Binh , Wang Qian , Gueritte Francoise 
Published: April 2012

AbstractThe title reaction of chrysin (I) can be controlled by the conditions: simply running in a solvent mixture, the process affords C‐6 substituted products, whereas in the presence of aqueous NaOH, C‐8 substitution takes place.
Optimal energy consumption in refrigeration systems ‐ modelling and non‐convex optimisation
Authors: Hovgaard Tobias Gybel , Larsen Lars F. S. , Skovrup Morten J. , Jørgensen John Bagterp 
Published: April 2012

AbstractSupermarket refrigeration consumes substantial amounts of energy. However, due to the thermal capacity of the refrigerated goods, parts of the cooling capacity delivered can be shifted in time without deteriorating the food quality. In this study, we develop a realistic model for the energy consumption in super market refrigeration systems. This model is used in a Nonlinear Model Predictive Controller (NMPC) to minimise the energy used by operation of a supermarket refrigeration system. The model is non‐convex and we develop a computational efficient algorithm tailored to this problem that is somewhat more efficient than general purpose optimisation algorithms for NMPC and still near to optimal. Since the non‐convex cost function has multiple extrema, standard methods for optimisation cannot be directly applied. A qualitative analysis of the system's constraints is presented and a unique minimum within the feasible region is identified. Following that finding we propose a tailored minimisation procedure that utilises the nature of the feasible region such that the minimisation can be separated into two linear programs; one for each of the control variables. These subproblems are simple to solve but some iterations might have to be performed in order to comply with the maximum capacity constraint. Finally, a nonlinear solver is used for a small example without separating the optimisation problem, and the results are compared to the outcome of our proposed minimisation procedure for the same conceptual example. The tailored approach is somewhat faster than the general optimisation method and the solutions obtained are almost identical. © 2012 Canadian Society for Chemical Engineering
Leaching kinetics of copper flotation tailings in aqueous ammonia/ammonium carbonate solution
Authors: You‐Cai Liu , Wei Yang , Jian‐Gang Fu , Li‐Feng Li , Dong Qian 
Published: April 2012

AbstractThe experiments of agitation leaching were carried out in aqueous ammonia/ammonium carbonate solution, to recover copper from the flotation tailings of waste copper oxide residue. The main copper minerals contained in the flotation tailings are chrysocolla, malachite, and cuprite, with the copper grade of 1.12%. Effects of lixiviant concentration, solid‐to‐liquid ratio, stirring speed, and reaction temperature on copper leaching ratios at various time were investigated. It is found that the leaching ratio almost cannot be affected by time after 90 min of leaching. The optimised processing conditions have been determined, under which the leaching ratio of 70.6% is obtained. Kinetics analysis indicates that the copper leaching ratio is controlled by diffusion through the product layer in the initial 60 min of leaching, and corresponding measures to strengthen the copper extraction is proposed, with the activation energy of 32.3 kJ/mol. © 2012 Canadian Society for Chemical Engineering
PH sensitive structural uniformity of rice husk ash‐derived MCM‐41 silica
Authors: Teabpinyok Nopporn , Chareonpanich Metta , Samingprai Sutheerawat , Limtrakul Jumras 
Published: April 2012

AbstractIn this study, highly uniform MCM‐41 mesoporous silica was synthesised from rice husk ash‐derived sodium silicate using cetyltrimethyl ammonium chloride (CTAC) as a template. The chemical composition of the gel mixture was based on a SiO2:CTAC:H2O molar ratio of 1:0.5:75. When the pH value was initially controlled at ranges of 5.0–10.5 for 5 h and then immediately adjusted to 11.25 for the next 1 h, the structural uniformity of MCM‐41 was abruptly increased by 3.3–7.5 times of the single pH value at 11.25, respectively. Moreover, thermal and hydrothermal stabilities at 900 and 250°C were clearly observed. © 2012 Canadian Society for Chemical Engineering