bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exergy analysis and flowsheet modification of PT. PUSRI II Palembang's reformer unit for the production of synthesis gas from natural gas
Authors: Djoni Bustan Muhammad , Mahadzir Shuhaimi , Kharismadewi Dian 
Published: March 2011

AbstractSeveral processes which produce synthesis gas from natural gas have been analyzed by the exergy method. To minimize the exergy losses associated to chemical reaction, it is important to manage the exergy losses through the analysis, reconsidering the chemical path. A generally applicable and schematic way of performing exergy analysis and dealing with their results are illustrated. It is integrated to the modified flowsheeting reformer. As petrochemical industry in Indonesia, PT. Pupuk Sriwijaya II Palembang uses natural gas as a raw material to produce synthesis gas through the primary and the secondary reformers in a series. In the modified flowsheeting reformer, partial oxidation process has been added before the primary reformer and the secondary reformer has been eliminated from the process pathways. The exergy method of analysis has been implemented for each process, in order to calculate the exergies of the material streams along with the energy and mass‐balance calculations both in the modified flowsheeting reformer and in a series process of the primary and the secondary reformers. And, the results of the calculations of the modified flowsheeting reformer in the process proposed modification are then compared to the results of the calculations of the series process of reformers in the existing conventional process. From the analysis, the overall exergy losses in a series process of the primary and secondary reformers can be reduced until 61.33%, by applying the modified flowsheeting reformer. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
Evolution of the precipitation kinetics, morphology, and permeation performance of phenolphthalein poly(ether sulfone) hollow‐fiber membranes with polyvinylpyrrolidones of different molecular weights as additives
Authors: Lang Wan‐Zhong , Chu Lian‐Feng , Guo Ya‐Jun 
Published: March 2011

AbstractPhenolphthalein poly(ether sulfone) (PES‐C) hollow‐fiber ultrafiltration (UF) membranes were fabricated by wet spinning and dry‐jet/wet spinning (10‐cm air gap) processes with polyvinylpyrrolidones (PVPs) of different molecular weights as additives. Light transmittance experiments were performed to obtain insight into the precipitation kinetics of PES‐C/PVP/N‐methyl‐2‐pyrrolidone (NMP) dope solutions. The morphology and permeation performance of the prepared PES‐C hollow‐fiber membranes were well characterized and elucidated with scanning electron microscopy and UF experiments in addition to the precipitation kinetics. The thermal and mechanical properties of the membranes were also studied. Experiments demonstrated that all PES‐C/PVP/NMP dope solutions experienced instantaneous demixing with pure water as the coagulant, and the precipitation rate decreased as the molecular weight of PVP increased. A double, fingerlike structure occurred in the PES‐C hollow‐fiber membranes spun with PVPs of low molecular weight (10,000, 24,000, or 58,000) as additives; however, a spongelike structure occurred in the PES‐C membranes with PVP with a molecular weight of 1,300,000 because of its very low precipitation rate. The pure water permeation (PWP) flux decreased and the rejection of lysozyme increased for the prepared PES‐C membranes as the molecular weight of PVP increased. The largest PWP flux of 149 L m−2 h−1 bar−1 was acquired for dry‐jet/wet‐spun PES‐C membranes with PVP with a molecular weight of 10,000 as an additive. The rejection of bovine serum albumin for the prepared PES‐C membranes was greater than 98%, and the rejection of lysozyme ranged from 47.1 to 89.4%; this indicated typical UF membranes. The decomposition temperature of the PES‐C membranes containing PVP was lower than that of the original polymer and decreased as the molecular weight of PVP increased. The break strain and the elongation at break were enhanced as the PVP molecular weight increased. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Effect of the tie‐layer thickness on the delamination and tensile properties of polypropylene/tie‐layer/nylon 6 multilayers
Authors: Khariwala D. , Ling M. , Hiltner A. , Baer E. 
Published: March 2011

AbstractThis study examined the effect of the tie‐layer thickness on the delamination behavior of polypropylene/tie‐layer/nylon 6 multilayers. Various maleated polypropylene resins were compared for their effectiveness as tie‐layers. Delamination failure occurred cohesively in all the multilayer systems. Two adhesion regimes were defined according to the change in the slope of the linear relationship between the delamination toughness and the tie‐layer thickness. The measured delamination toughness of the various tie‐layers was quantitatively correlated to the length of the damage zone that formed at the crack tip. In addition, the effect of the tie‐layer thickness on the multilayer tensile properties was correlated with the delamination behavior. The fracture strain of the multilayers decreased with decreasing tie‐layer thickness. An examination of the prefracture damage mechanism of the stretched multilayers revealed a good correlation with the delamination toughness of the tie‐layers. In thick tie‐layers (>2 μm), the delamination toughness was great enough to prevent the delamination of the multilayers when they were stretched. In thin tie‐layers (<2 μm), the delamination toughness of all the tie‐layers was low; consequently, delamination led to premature fracture in the stretched multilayers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polypropylene/wasted poly(ethylene terephthalate) fabric composites compatibilized by two different methods: Crystallization and melting behavior, crystallization morphology, and kinetics
Authors: Zhidan Lin , Juncai Shen , Chao Chen , Xiuju Zhang 
Published: March 2011

AbstractPolypropylene (PP)/wasted poly(ethylene terephthalate) (PET) fabric composites and these composites modified by maleic anhydride grafted polypropylene (PP‐g‐MA) and reactive monomers were prepared with a twin‐screw extruder. The crystallization morphology, nonisothermal crystallization and melting behavior, crystallization kinetics, and isothermal crystallization kinetics were investigated with differential scanning calorimetry. The results indicated that the wasted fabric (WF) had a heterogeneous nucleation effect on PP in the composites, and this increased the crystallization temperature and induced PP to form transcrystallinity. PP‐g‐MA further increased the crystallization temperature; however, the reactive monomers weakened the heterogeneous nucleation effect of WF. Also, the premelting temperature affected the crystallization and melting behavior of the composites significantly. The Avrami equation and the Mo method provided a fairly satisfactory description of the crystallization kinetics. The crystallization activation energy, nucleation constant, and folding surface free energy of PP were markedly reduced in the PP/waste PET fabric composites and the compatibilized composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 00: 000–000, 2011
Different properties for poly(3,4‐ethylenedioxythiophene) films derived from single or multiple polymerization steps
Authors: Aradilla David , Estrany Francesc , Alemán Carlos 
Published: March 2011

AbstractFilms of poly(3,4‐ethylenedioxythiophene) were prepared with single and multiple electropolymerization steps, where the numbers of polymerization steps (n's) were 3, 5, and 7, with identical experimental conditions and total polymerization times (τ's). The electroactivity of the films prepared with multiple steps remained almost unaltered when n increased, with the ability of the films to store charge with n > 3 being smaller than that of the films with similar thicknesses but derived from a single electrodeposition step. In contrast, the stability of the films produced with n polymerization steps was significantly higher than that of the films derived from a single step with the same τ, with the difference between the two systems increasing with n, that is, τ used to yield the films. On the other hand, although the morphological and topological characteristics of the surface and the electrical conductivity were affected by the procedure used to produce the films, the organization of the polymer molecules in the crystalline phase, the thermal stability, and the electronic properties (ionization potential, electron affinity, and lowest π–π* transition energy) were practically identical in both cases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis of poly(ethylene glycol)–dopamine conjugates and their controlled drug‐release behaviors
Authors: Zhang Juan , Liu Yi‐Feng , Bo Lan , Qiao Chang‐An 
Published: March 2011

AbstractDopamine (DA) was covalently linked via succinic anhydride spacers to poly(ethylene glycol)s (PEGs) with average molecular weights of 4000 (PEG4000), 6000 (PEG6000), and 10,000 (PEG10000). The chemical modification of the PEGs was conducted by a two‐step protocol: (1) the preparation of PEG having carboxylic end groups and (2) the synthesis of PEG4000–DA, PEG6000–DA, and PEG10000–DA. The controlled drug‐release studies were performed in pH 1.1, 7.4, and 9.0 buffer solutions, The results demonstrate that under the same conditions, the rate of hydrolysis for PEG10000–DA was the slowest among three prodrugs, and a greater amount of DA could be detected being released from the prodrug matrices in the presence of α‐chymotrypsin in a buffer solution with pH 8.0. Also, these novel prodrugs could slowly release the active drug molecules and improve the pharmacokinetics of DA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of swelling and reactive dyeing on the accessibility of cotton to cellulase enzymes
Authors: Paul Roshan , Teli Mangesh D. 
Published: March 2011

AbstractThe main objective of this study was to determine the effect of intracrystalline and intercrystalline swelling agents and reactive dyes on the accessibility of cotton cellulose to commercial cellulase enzymes. Both types of swelling agents improved the accessibility, and intracrystalline swelling agents showed better results, as the accessibility to difficult‐to‐reach crystalline regions was increased. As expected, the reactive dyes inhibited the accessibility of the enzymes to some extent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis of graft copolymers of binary vinyl monomer mixtures onto acetylated Saccharum spontaneum L and characterization
Authors: Maiti Mithu , Jindal Rajeev , Kaith Balbir Singh , Jana Asim K. 
Published: March 2011

AbstractMethylmethacrylate (MMA) + acrylamide (AAm), MMA + acrylonitrile (AN), and MMA + acrylic acid (AA) binary vinyl monomer mixtures were graft copolymerization onto acetylated Saccharum spontaneum L, was carried out and maximum graft yield (185.6 %) was found with MMA+AAm binary mixture. Synthesized graft co‐polymers were characterized with FT‐IR spectrophotometry, scanning electron microscopy (SEM), thermal analysis TGA/DTA/DTG, and X‐ray diffraction (XRD) techniques. Thermal stability of Ss‐g‐poly(MMA + AAm) was found to be more than that of natural, acetylated S. spontaneum fiber and other graft copolymers. Although on grafting, percentage crystallinity and crystallinity index were found to decrease but graft copolymers were found to exhibit more moisture, chemical, and thermal resistance. Also, it can be observed that the surface of the grafted fibers is highly rough in comparison with the ungrafted fiber. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis, characteristics, and phase behavior of a thermosensitive and pH‐sensitive polyelectrolyte
Authors: Zhou Wenting , An Xueqin , Gong Jun , Shen Weiguo , Chen Zhiyun , Wang Xiaoyong 
Published: March 2011

AbstractA series of poly(N‐isopropylacrylamide‐co‐methacrylic acid‐co‐octadecyl acrylate) (poly(NIPAM‐co‐MAA‐co‐ODA)) with different monomer molar ratios was synthesized. Critical micelle concentration (CMC) of the polyelectrolyte solution was determined and the CMC increase with methacrylic acid content in the polyelectrolyte. The phase behaviors of the polyelectrolyte solution were studied, and the effects of various factors on the phase transition were discussed. The experimental results indicate that the lower critical solution temperature and the phase transition pH depend on the monomer molar ratio in the polyelectrolyte. Effect of polyelectrolyte concentration on phase transition pH was studied, and results shown that the phase‐transition pH is independent of the polyelectrolyte concentration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Plasticization of poly‐L‐lactide for tissue engineering
Authors: Cuénoud Matthieu , Bourban Pierre‐Etienne , Plummer Christopher J.G. , Månson Jan‐Anders E. 
Published: March 2011

AbstractPlasticization of medical grade poly‐L‐lactide (PLLA) by addition of polyethylene glycol (PEG) with various molar masses has been evaluated as means of producing low stiffness matrices for bioresorbable scaffolds for soft‐tissue engineering applications. As reported previously, the Tg of injection molded specimens of the PLLA/PEG blends decreased strongly with PEG content, so that at PEG contents of 15 and 25 wt % it became significantly lower than normal human body temperature, implying an essentially rubber‐like mechanical response in vivo. The degree of crystallinity of the moldings also increased strongly with PEG content, reaching a maximum of about 60 wt % at 25 wt % PEG. Moreover, after the immersion in phosphate‐buffered saline for 5 days in 37°C to simulate conditions in vivo, the moldings with the highest PEG contents showed increased water uptake and, for relatively low molar mass PEG, significant mass loss, associated with phase separation and leaching of the PEG. Blends with relatively low PEG contents also showed large increases in their degree of crystallinity. The implications of these changes for the in vivo performance of the blends and their potential for development as matrices for bioresorbable scaffolds are discussed in the light of results from a series of PLLA/PEG copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Strengthening and toughening of thermoplastic polyolefin elastomer using polypropylene‐grafted multiwalled carbon nanotubes
Authors: Li Chaoqun , Deng Hua , Wang Ke , Zhang Qin , Chen Feng , Fu Qiang 
Published: March 2011

AbstractIn this article, it is demonstrated that simultaneously strengthened and toughened nanocomposites based on polypropylene/EPDM thermoplastic elastomer (TPO) matrix can be achieved through enhanced adhesion between MWNTs and polymer matrix by using PP grafted multiwalled carbon nanotubes (MWNTs). To improve the interface between filler and matrix, MWNTs were treated with acid, or covalently linked to polypropylene. The chemical and morphological transformation of the modified MWNTs, and its effect on the morphology and mechanical properties of the composites are investigated. The strengthening and toughening mechanism is discussed regarding the structural property relationship. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Bahnbestimmung als Randwertproblem. I
Authors: Bucerius H. 
Published: March 2011

AbstractDer rein dynamische Teil der Gaussschen Bahnbestimmungsmethode wird in vektorieller Schreibweise als eine Randwertaufgabe formuliert und die zugehörige Integralgleichung aufgestellt. Die verschiedenen Näherungsausdrücke für die Verhältnisse der Dreiecksflächen werden von diesem Standpunkt charakterisiert und erweitert. Die Lösung des Randwertproblems durch sukzessive Approximation entspricht dem Sektor‐zu‐Dreieck‐Verfahren, dessen Konvergenz sowohl vom Integralgleichungs‐Standpunkt als auch nach einer differentiellen Methode bei Zugrundelegung der Gauss‐Fabritiusschen Formulierung des Iterationsverfahrens untersucht wird.
Bahnbestimmung als Randwertproblem. II
Authors: Bucerius H. 
Published: March 2011

AbstractNach allgemeiner Kritik der älteren Konvergenzbetrachtungen zur Gaussschen Methode auf Grund von Abschätzungen nach Potenzen der Zwischenzeiten werden Rechenschemata für 3 und 4 Beobachtungen mit einem Iterationsverfahren ohne Gausssche Gleichung aufgestellt und an Beispielen von kleinen Planeten praktisch erprobt. In der folgenden Konvergenztheorie, die eine Erweiterung der Untersuchung im I. Teil darstellt, wird die Berechtigung des Verfahrens für das Hauptanwendungsgebiet der kleinen Planeten bewiesen. Einige für die Theorie und Praxis der Bahnbestimmung wichtige Folgerungen werden anschließend diskutiert.
Physische Beobachtungen von Kometen. VII
Authors: Beyer M. 
Published: March 2011

AbstractDer vorliegende Bericht setzt eine seit 1933 laufende Serie von Veröffentlichungen über physische Beobachtungen von Kometen fort und schließt an Astron. Nachr. 275.237 (1947), Mitteilungen der Hamburger Sternwarte Nr. 61, an. Er umfaßt die Beobachtungen von 15 Kometen aus dem Zeitabschnitt 1946 Juni bis 1949 April, die in der gleichen Weise mitgeteilt und diskutiert werden wie bisher. Das Hauptgewicht ist wieder auf eine möglichst genaue Bestimmung der Gesamthelligkeiten gelegt, um die Beziehungen zwischen der Helligkeitsentwicklung und dem Sonnenabstand der einzelnen Kometen ableiten und vergleichen zu können. Zu diesem Zweck sind die auf die Einheit der Abstände r und Δ des Kometen von der Sonne bzw. von der Erde bezogenen Normalhelligkeiten H0 und die den Helligkeitsverlauf bestimmenden Exponenten n2 des Sonnenabstandes r für die verschiedenen Kometen aus den Beobachtungen abgeleitet. Da das vom Verfasser benutzte Beobachtungsverfahren fast stets größere Helligkeiten liefert, als sie die sonst üblichen Methoden ergeben, sind zum Vergleich auch Gesamthelligkeiten von Kugelhaufen und Spiralnebeln auf dieselbe Weise beobachtet worden. Diese Ergebnisse stimmen recht gut mit den neuesten photovisuellen Messungen überein, so daß kein Anlaß zur Änderung des Beobachtungsverfahrens oder zu einer Korrektion der damit gewonnenen Größen besteht. Neben Messungen und Schätzungen der Kernhelligkeiten und des jeweiligen Durchmessers der Komaist auch der Schweifentwicklung besondere Beachtung geschenkt. In Einzelfällen sind Beziehungen zwischen dem Sonnenabstand des Kometen und der Ablenkung seines Schweifs von der Richtung des Strahlungsdrucks der Sonne festgestellt. Von den beiden Kometen Bester (1947k) und Honda‐Bernascont (1948g) wurden auch mehrere Objektivprismen‐Spektrogramme erhalten. Zum Schluß wird auf Grund gleichzeitiger Beobachtungen von mehreren Kometen das Bestehen von Beziehungen zwischen der Sonnentätigkeit und sekundären Schwankungen der Kometenhelligkeit eindeutig nachgewiesen. Bestimmt man für die einzelnen Kometen unter Berücksichtigung ihrer heliozentrischen Lage die für sie gültigen Kurven der Sonnenflecken‐Relativzahlen, so zeigen diese eine auffallende Parallelität mit den sehr unregelmäßigen und oft rasch verlaufenden Helligkeitsschwankungen der Kometen. Da auch in größeren Sonnenabständen weder Verzögerungen dieser Erscheinungen noch Veränderungen ihrer Amplituden erkennbar sind, kann es sich nur um reine Strahlungseffekte handeln. Als Quellen dieser Strahlung kommen die größeren Tätigkeitsherde auf der Sonnenoberfläche in Betracht, wobei jedoch nicht allein die zentralen, sondern in geringerem Umfange auch die in den Randgebieten der Sonnenscheibe liegenden Störungsfelder wirksam sind.
Über den Lichtwechsel des langperiodischen Veränderlichen TY Cephei
Authors: Hassenstein W. 
Published: March 2011

AbstractDer Helligkeitswechsel von TY Cep wird auf Grund des gesamten verfügbaren Beobachtungsmaterials — einer photometrischen Reihe des Verfassers und 7 weiterer Reihen — untersucht. Die Lichtkurve verläuft in dem betrachteten Zeitraum von 30 Jahren näherungsweise periodisch in einer Periode von 330d Dauer, nimmt aber von Zyklus zu Zyklus sehr wechselnde Formen an. Hauptmerkmal der Kurvengestalt ist das rhythmische Auftreten ausgeprägter Hauptminima und breiter, vielfach durch Nebenminima geteilter Maxima. Der Veränderliche ist trotz einer gewissen Verwandtschaft mit den RV Tauri‐Sternen als Mitglied der Mira‐Klasse zu betrachten, und zwar einer nicht häufig vorkommenden, nach H. Ludendorff als R Centauri‐Klasse bezeichneten Unterklasse, für die eine Helligkeitskurve der Form γ charakteristisch ist.
Controlled ex‐vivo plasma hydrolysis of valaciclovir to acyclovir demonstration using tandem mass spectrometry
Authors: Goswami Dipanjan , Khuroo Arshad , Gurule Sanjay , Modhave Yogesh , Monif Tausif 
Published: March 2011

ABSTRACTPlasma estimation of valaciclovir, an antiviral drug, is challenging due to both in‐vivo and ex‐vivo hydrolysis to active metabolite acyclovir. A simultaneous method is described involving the solid‐phase ion‐exchange extraction procedure requiring 100 μL of plasma volume, a reverse‐phase Lichrosphere RP Select B (125 × 6 mm, 5 μm) column and isocratic mobile phase to achieve the desired chromatographic separation. ESI‐MS/MS multiple reaction monitoring in positive polarity, detected mass pairs for valaciclovir (m/z 325.5 → 152.2), acyclovir (m/z 226.3 → 152.2) and respective internal standards valganciclovir (m/z 307.1 → 220.3) and acyclovir‐d4 (m/z 230.2 → 152.0). Fully fledged method validation was evaluated as per current regulatory requirements and results were deemed acceptable. The plasma samples showed extensive hydrolysis of valaciclovir when collected or processed at room temperature, without buffer stabilization prior to storage at −15°C. Our results showed that using prechilled K3EDTA vacutainers immersed in an iced‐water bath during blood sample collection, and addition of 50% orthophosphoric acid solution to plasma samples prior to storage at −50°C for at least 120 days controlled the hydrolysis of valaciclovir to acyclovir. While monitoring drug absorption into systematic circulation, the valaciclovir to acyclovir formation ratio was improved to 1:20 in healthy volunteers for the first time. Copyright © 2011 John Wiley & Sons, Ltd.
Making Decisions about Parental Mental Health: An Exploratory Study of Community Mental Health Team Staff
Authors: Rouf Khadj , Larkin Michael , Lowe Geoff 
Published: March 2011

Adult mental health problems can impact on parents, and research highlights that their children are at higher risk of developing mental health problems. In extreme cases, mental health problems are associated with a risk of fatal child abuse. Despite this, there are few studies exploring clinical decision‐making by adult mental health professionals.‘In extreme cases, mental health problems are associated with a risk of fatal child abuse’This study used qualitative methods to explore Community Mental Health Team (CMHT) workers' experiences of decision‐making in the interface between mental health and child welfare. Workers were interviewed about their experiences of clinical decision‐making regarding child welfare. Interviews and accounts were analysed using Interpretative Phenomenological Analysis. Influences on decision‐making were explored and triangulated with the accounts of Named Nurses for Child Protection.The findings revealed that CMHT participants were aware of their responsibilities towards children, but a complex synthesis of factors impacted on their sense‐making about risk and welfare. Three superordinate themes emerged: the tensions of working across systems; trying to balance the perceptions and feelings involved in sense‐making; and the role that interpersonal dynamics play in the understanding and management of risk. This paper focuses in particular on perceptions and feelings. Copyright © 2011 John Wiley & Sons, Ltd.‘A complex synthesis of factors impacted on their sense‐making about risk and welfare’