bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of sulfonated block copolyimides derived from 4,4'‐sulfide‐bis(naphthalic anhydride) for proton exchange membranes
Authors: Chen Guofei , Pei Xueliang , Wei Haibing , Xu Lubo , Fang Xingzhong 
Published: October 2014

ABSTRACTA series of sulfonated copolyimides (SPIs) with hydrophilic segment length of 20–60 based on 4,4′‐sulfide‐bis(naphthalic anhydride) (SBNA) have been successfully synthesized to improve hydrolytic stability and proton conductivity. The SPI membranes were cast from their m‐cresol solutions, and they were characterized by determining the water uptake, water swelling ratio, mechanical properties, hydrolytic stability, oxidative stability, and proton conductivity. It was found that the water uptake of SPI membranes was low and decreased as the hydrophilic segment length increased, which led to good dimensional stability. In addition, the SPI membranes with low ion‐exchange capacity (IEC) value displayed excellent hydrolytic stability and retained good mechanical properties even after harsh hydrolysis testing, in which the block SPI with hydrophilic segment length of 40 had the best hydrolytic stability, while those with high IEC value showed an apparent decrease. All of the block SPI membranes show better conductivity than the random ones at the temperature range from 30 to 70°C. Interestingly, the proton conductivities of random SPI membranes were higher than that of corresponding block ones at 90°C. The block SPI with hydrophilic segment length of 40 gave the highest proton conductivity as the temperature increased among the block SPIs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41501.
Copper(II)‐Mediated Transformation of a Tridentate Non‐Innocent Ligand into a Tetradentate Salen‐Type Innocent Ligand
Authors: Ghorai Samir , Mukherjee Chandan 
Published: October 2014

AbstractA non‐innocent ligand, H4L, was synthesized by introducing a CH2NH2 group at the ortho carbon atom to the aniline moiety of 2‐anilino‐4,6‐di‐tert‐butylphenol. The new ligand was characterized by IR and NMR spectroscopy and mass spectrometry techniques. Upon treatment with CuCl2⋅2 H2O, this non‐innocent ligand provided a mononuclear four‐coordinate salen‐type CuII complex by complete modification of the ligand backbone. The complex was characterized by IR spectroscopy, mass spectrometry, X‐ray single‐crystal diffraction, electron paramagnetic resonance (EPR) spectroscopy, and UV/Vis/near‐IR spectroscopy techniques. X‐ray crystallographic analysis showed an asymmetric environment around the CuII center with a small (≈12°) twist between the two biting planes. Analysis of the X‐band EPR spectrum also supported the asymmetric environment and also indicated the presence of an unpaired electron on the d orbital. The UV/Vis/near‐IR spectrum showed strong absorption bands for metal‐to‐ligand charge transfer and ligand‐to‐metal charge transfer along with a CuII‐centered d–d transition. Mechanistic investigation of the formation of complex 1 indicated that modification of the ligand backbone proceeded through ligand‐centered amine to imine oxidation as well as through CN bond‐breaking processes. During these processes, 3,5‐di‐tert‐butyl‐1,2‐benzoquinone and 2‐aminobenzylidene were produced. Ammonia, generated in situ through hydrolysis of the imine to the aldehyde, reacted with 3,5‐di‐tert‐butyl‐1,2‐benzoquinone to form the corresponding 3,5‐di‐tert‐butyl‐1,2‐iminobenzoquinone moiety, which upon two‐electron reduction in the reaction medium formed 3,5‐di‐tert‐butyl‐1,2‐aminophenol. This aminophenol underwent condensation with the H2L5 ligand that was formed by self‐condensation of two molecules of 2‐aminobenzaldehyde and provided the modified ligand backbone.
Zweiachsige Lastabtragung von Brettsperrholzplatten
Authors: Bogensperger Thomas , Silly Gregor 
Published: October 2014

AbstractBauen mit massiven Brettsperrholzelementen (BSP‐Elementen) gewann in den letzten Jahren an Bedeutung. Beginnend mit dem Einfamilienhausbau vor mehr als 15 Jahren wurden und werden mittlerweile immer größere Bauaufgaben angedacht und realisiert. Als Beispiele der aktuell größten Bauwerke in der Holz‐Massivbauweise können der Murray Grove Tower und das Bridboard House – 2008 bzw. 2010 in London errichtet – angeführt werden. Die jeweils achtgeschossigen Bauwerke wurden komplett mit dem noch “jungen” Baustoff Brettsperrholz (BSP) realisiert.Traditionell erfolgt die Berechnung von Deckenelementen aus BSP als einachsig gespannter Plattenstreifen. Damit kann allerdings nur die Haupttragrichtung der orthotrop wirkenden BSP‐Platte erfasst werden. Um auch die Nebentragrichtung für die Bemessung zu nutzen, werden im vorliegenden Beitrag sämtliche Steifigkeitskennwerte von BSP‐Platten erläutert. Damit können auch Sonderfälle wie Deckenaussparungen oder punktgestützte Platten, welche eine 2D‐Plattenberechnung nach der orthotropen, schubnachgiebigen Plattentheorie (REISSNER‐MINDLIN) erfordern, untersucht werden.Two‐axial load transfer of Cross‐Laminated‐Timber platesIn the last years building activity with solid Cross Laminated Timber (CLT) elements gained remarkable relevance. Starting with single family houses over 15 years ago medium and large sized building construction jobs are analysed and solved in the meantime. Two examples for large multi‐storey houses with eight floors each, erected completely with CLT, can be cited here: on the one hand the Murray Grove Tower (2008) and on the other hand the Bridboard House (2010) – both realized in London. Structural design of these CLT‐plates is performed traditionally as simply supported uniaxial plate. Only the stronger, more important main direction of CLT‐plates, which is defined as the orientation of the outer layers, is treated by this assumption. In order to include the minor important orthogonal direction of CLT in a two dimensional plate theory all plate stiffness coefficients of CLT‐plates are illustrated and discussed in the present paper. Consequently special cases as large cutouts in CLT‐plates and column supported CLT‐plates can be treated with the well known REISSNER‐MINDLIN plate theory, which includes deformation due to bending and shear.
Anmerkungen zur Bemessung von Dübeln nach europäischen Regelungen
Authors: Mallée Rainer 
Published: October 2014

AbstractDie Bemessung von Dübeln nach europäischen Vorschriften führt in der überwiegenden Zahl der Anwendungsfälle zu logischen Ergebnissen. In Einzelfällen können aber auch widersprüchliche Resultate auftreten. Zum Beispiel kann der charakteristische Widerstand einer Befestigung mit zunehmender Verankerungstiefe der Dübel abnehmen. In diesem Beitrag wird anhand einiger Beispiele gezeigt, dass dies nicht auf Fehler bei der Berechnung, sondern auf das Bemessungsverfahren selbst zurückzuführen ist, und es werden erste Lösungsvorschläge unterbreitet.Comments on the design of anchors according to European regulationsThe design of anchors in accordance with European regulations gives in the vast majority of applications logical results. In certain cases, also contradictory results can occur. For example, the characteristic resistance of a fastening may decrease with increasing embedment depth of the anchor. In this paper, it is shown by means of examples that this is not due to errors in the calculation but due to weaknesses of the design model. First proposals for a solution are submitted.
Entwicklung eines weitgespannten Sandwichdeckensystems mit integrierter Haustechnik in Verbundbauweise
Authors: Friedrich Thomas , Kornadt Oliver , Kurz Wolfgang , Schnell Jürgen 
Published: October 2014

AbstractIn mehreren Schritten wurde ein multifunktionales Deckenelement entwickelt, welches zwischenzeitlich bei zahlreichen Projekten erfolgreich eingesetzt wurde. Dabei waren vielfältige Anforderungen zu beachten. Neben der geringen Eigenlast und der geringen Verformung bei großer Schlankheit zählen dazu die Aspekte des baulichen Brandschutzes, der integrierten Haustechnik und der positiven Beeinflussung von Behaglichkeit und Raumakustik. Das Deckensystem erfordert zwangsläufig eine Koordination der Fachplaner in der Planungsphase. Alle Vorteile einer werksmäßigen Vorfertigung können genutzt werden, sodass kurze Bauzeiten bei gleichmäßiger Fertigungsqualität und wettbewerbsfähigen Kosten erreicht werden können. Im Bereich der Verbundmittel besteht noch ein Optimierungspotenzial.Developement of a long‐spaned sandwich‐slab‐system with integrated service engineering in composite construction methodDedicated to the 80th birthday of Professor Dr.‐Ing. Dr.‐Ing. e. h. Gert KönigA multifunctional slab system, which has been used successfully in numerous projects, has been developed in several steps. Within this development various requirements had to be fulfilled. In addition to the minor dead load and slenderness, aspects like fire protection, the integrated building services, the positive influence to the users comfort and the room acoustics characterize the slab system. This slab system makes necessary a coordinated work of all engineers in the planning phase. All advantages of precast production can be leveraged. So short construction periods with a constant production quality and competitive costs can be achieved. There is still some optimization potential in the field of the shear connectors.
Querkraftversuch an einem Durchlaufträger aus Spannbeton
Authors: Maurer Reinhard , Gleich Philipp , Zilch Konrad , Dunkelberg Daniel 
Published: October 2014

AbstractDie Nachrechnungen bestehender älterer deutscher Spannbetonbrücken auf Grundlage der aktuell gültigen Normen zeigen im Allgemeinen erhebliche Defizite in Bezug auf die erforderliche Querkraftbewehrung in Längsrichtung. Es ist jedoch bisher kein Querkraftversagen eines bestehenden deutschen Brückenbauwerks bekannt.Bis heute gibt es nur sehr wenige Versuche an Spannbetonbalken als Durchlaufträger. Um das Tragverhalten durchlaufender Spannbetonbalken eingehender zu untersuchen, wurde im Rahmen eines von der BASt beauftragten Forschungsvorhabens an der TU Dortmund ein Großversuch an einem vorgespannten Zweifeldträger durchgeführt. Dabei sollte auch der zusätzliche Traganteil aus einer Druckbogenwirkung genauer betrachtet werden. Zur kontinuierlichen Erfassung der Beanspruchungen im gesamten Bauteil unter allen Laststufen wurde eine umfassende Messtechnik installiert.Im vorliegenden Beitrag werden der Großversuch und die daraus gewonnenen wesentlichen Erkenntnisse dargestellt. Zudem erfolgen eine Versuchsauswertung auf Basis geltender Normen und ein Vergleich mit dem Druckbogenmodell.Shear testing on a prestressed continuous concrete beamThe structural assessment of existing older prestressed concrete bridges on the basis of current standards often uncovers substantial deficits in terms of the required shear reinforcement in the main girders of bridge superstructures. However, shear failures of existing German bridge structures have not been reported so far.Until now, only few tests on prestressed continuous concrete beams have been carried out. In order to investigate the load bearing capacity of such beams more precisely, a large scale experiment was executed at TU Dortmund in the course of a research project funded by the Federal Highway Research Institute (BASt). Within this project a particular focus was put on the investigation of the additional shear load bearing capacity caused by the compressive arch effect. Therefore an extensive range of measurement devices was used in the experiment to guarantee the continuous recording of structural behavior and internal forces.In this contribution the large scale experiment as well as the main findings are presented. An interpretation of the test results based on current standards and a comparison with the compressive arch model are carried out.
Schubverhalten von Biegebauteilen ohne Querkraftbewehrung
Authors: Tue Nguyen Viet , Theiler Werner , Tung Nguyen Duc 
Published: October 2014

AbstractIn diesem Aufsatz wird ein neuer Ansatz zur Beschreibung des Querkraftverhaltens von schubschlanken Biegebauteilen aus Stahlbeton ohne Querkraftbewehrung vorgestellt. Grundgedanke des Ansatzes ist die Analyse der Hauptzugspannungen im Bereich der Rissspitzen infolge Biegebeanspruchung. Durch die Betrachtung der Hauptzugspannungen aus Biegung und Querkraft entsteht ein potenzielles Schubband für die spätere Bildung eines kritischen Schubrisses. Die Breite des Schubbands wird mit der Abnahme des Biegemoments und der Zunahme der Querkraft größer, sodass die Biegebeanspruchung in einem Schubfeld einen positiven Einfluss auf die Querkrafttragfähigkeit hat. Mit dem neuen Ansatz können die Traglasten und die Rissbilder der Versuche verschiedener Schubfeldtypen in der Literatur erklärt werden, was mit den derzeit bekannten Ansätzen nicht immer möglich ist.Shear response of reinforced concrete members without stirrups under bendingThis contribution presents a new model to determine the shear capacity of reinforced concrete members under bending without shear reinforcement. The main idea of the model is the consideration of principal stress in the region of crack tips of the flexural cracks due to bending. A potential band for the formation of a critical shear crack that tends to connect the tips of existing flexural cracks can be assumed. The width of this band decreases with the increasing of the bending moment and gets larger when the shear force becomes higher. This means the bending moment affects positively the shear capacity. With the new model the shear capacity and the crack pattern in previous shear tests with different structural systems and loading conditions can be explained, which is generally not possible with the existing models.
Hypoxia influences protein transport and epigenetic repression of CHO cell cultures in shake flasks
Authors: Qian Yueming , Xing Zizhuo , Lee Sherry , Mackin Nancy A. , He Aiqing , Kayne Paul S. , He Qin , Qian Nan‐Xin , Li Zheng Jian 
Published: October 2014

AbstractShake flasks and bench‐top bioreactors are widely used for cell culture process development, however, culture performances significantly differ between them. In order to apply the results received from small‐scale cultures to production scale, it is important to understand the mechanisms underlying the differences between various culture systems. This study analyzes the expression patterns of Chinese hamster ovary (CHO) cells producing IgG‐fusion protein B0 cultured in shake flasks and 5‐L bench‐top bioreactors by CHO‐specific DNA microarrays. The data show that hypoxia was present in shake flask cultures but not in controlled, bench‐top bioreactors. Hypoxic conditions appeared to be associated with epigenetic repression resulting in decreased cell culture performance and protein productivity, which is also present during large‐scale bioreactor operations due to oxygen gradients. High protein productivity was associated with increased cellular machinery for protein transport and secretion in conjunction with decreased epigenetic repression in bench‐top bioreactor cultivation. Metal ions could improve cell growth and protein production under hypoxia and this condition could be mimicked in small‐scale bioreactors to facilitate cell culture process scale‐up.
Enantioseparation and thermodynamic study of naphthalene derivatives, new melatoninergic agonists, on coated amylose [tris(S)‐1‐phenylethylcarbamate] stationary phase. Transposition to preparative scale
Authors: Landagaray Elodie , Yous Saïd , Vaccher Claude , Lipka Emmanuelle 
Published: October 2014

AbstractThis work reports a high‐performance liquid chromatography normal‐phase methodology to elucidate enantiomers of naphthalene derivatives, evaluated as melatoninergic agonists. For this purpose four different polysaccharide based chiral stationary phases were evaluated, namely Chiralcel OD‐H (cellulose tris‐3,5‐dimethylphenylcarbamate), Chiralcel OJ (cellulose tris‐methylbenzoate), Chiralpak AD (amylose tris‐3,5‐dimethylphenylcarbamate) and Chiralpak AS (amylose tris‐(S)‐1‐phenylethylcarbamate) with different alcoholic modifiers on different amounts in n‐heptane. A temperature study was carried out, between 20 and 40 °C and the apparent thermodynamic parameters were calculated thanks to the Van't Hoff linearization. For all compounds (except 3), ΔΔH° and ΔΔS° exhibited positive values ranging from 791.2 to 9999.3 J/mol and from 3.9 to 37.8 J/K/mol respectively, indicating entropically driven separations. Optimized conditions led to goof resolution of 2.37 for compound 1 on Chiralpak AS, with heptane–2‐propanol 90:10 (v/v), at a temperature of 30 °C. Then they were transposed to the preparative scale for compound 1, generating 22 mg of each enantiomer with an 80% yield. The limits of detection and of quantification were determined to allow the calculation of the enantiomeric excess. They were found with very low values, equal to 0.32 and 1.05 µ m and 0.33 and 1.11 µ m, respectively, for peaks 1 and 2 of compound 1. Copyright © 2014 John Wiley & Sons, Ltd.
A Review on Gas‐Liquid Reactions in Light Oil Sweetening: Kinetics and Reactor Design Aspects
Authors: Ganguly Sudip K. , Varun Neetu , Kumar Sunil , Khatri Praveen K. , Jain Suman L. , Garg Madhukar O. , Pellegrini Laura A. 
Published: October 2014

AbstractThiols in liquefied petroleum gas are undesirable due to their foul odor and corrosive nature. The process of removing these thiols is termed as sweetening. Metal phthalocyanines are reported to be the most effective sweetening catalyst. However, the solubility of metal phthalocyanine is low in aqueous medium. Thus, in an effort to further improve upon the existing catalysts, a novel cobalt phthalocyanine sulfonamide catalyst was developed. Laboratory and commercial evaluation of this catalyst showed enhanced activity as compared to a commercial catalyst with comparable stability. With proven higher activity, comparable stability, design of grass root oxidizer using this catalyst is the next step. Design of oxidizers for an extractive sweetening process based on this catalyst in grass root refineries requires a rigorous kinetic model. The paper reviews the literature on sweetening kinetics and focuses on the concepts of design of laboratory reactors for reaction kinetics studies for such gas‐liquid reactions. Laboratory reactor systems can be useful for accurate estimation of kinetic parameters which can then be used to design industrial reactors and predict their performance.
Counting Active Sites on Titanium Oxide–Silica Catalysts for Hydrogen Peroxide Activation through In Situ Poisoning with Phenylphosphonic Acid
Authors: Eaton Todd R. , Boston Andrew M. , Thompson Anthony B. , Gray Kimberly A. , Notestein Justin M. 
Published: October 2014

AbstractQuantifying specific active sites in supported catalysts improves our understanding and assists in rational design. Supported oxides can undergo significant structural changes as surface densities increase from site‐isolated cations to monolayers and crystallites, which changes the number of kinetically relevant sites. Herein, TiOxdomains are titrated on TiOx–SiO2selectively with phenylphosphonic acid (PPA). An ex situ method quantifies all fluid‐accessible TiOx, whereas an in situ titration duringcis‐cyclooctene epoxidation provides previously unavailable values for the number of tetrahedral Ti sites on which H2O2activation occurs. We use this method to determine the active site densities of 22 different catalysts with different synthesis methods, loadings, and characteristic spectra and find a single intrinsic turnover frequency forcis‐cyclooctene epoxidation of (40±7) h−1. This simple method gives molecular‐level insight into catalyst structure that is otherwise hidden when bulk techniques are used.
An extended quadrature‐based mass‐velocity moment model for polydisperse bubbly flows
Authors: Yuan Cansheng , Kong Bo , Passalacqua Alberto , Fox Rodney O. 
Published: October 2014

AbstractAccurately predicting polydisperse bubbly flow is a nontrivial task due to the complexity of the bubble number density function (NDF) and the strong dependence of the instantaneous bubble velocity on the bubble size and shape. To describe polydisperse bubbly flow, a joint mass‐velocity NDF is adopted in this work. In the absence of mass transfer between phases and coalescence or breakage, the bubble mass is a conserved quantity from which the bubble size and shape can be found given the liquid pressure and surface tension. Quadrature‐based moment methods (QBMM) are applied to solve numerically the kinetic equation of the joint NDF using the extended quadrature method of moments (EQMOM) coupled with an open‐source incompressible Navier–Stokes solver for the liquid phase. Transport equations for the joint mass‐velocity moments are derived from a kinetic equation for the joint NDF and closure is attained using a monokinetic NDF valid in the limit of small bubble Stokes number. The integer moments with respect to mass are used to reconstruct the continuous univariate NDF with EQMOM, while the joint mass‐velocity moments are used to determine the bubble velocity as a continuous function of the bubble mass. The model is first applied to simulate a quasi‐2‐D bubble column with different aeration profiles and a narrow bubble size distribution in order to validate the approach with experimental data from the literature. Additional cases with a wide continuous bubble size distribution are used to show the ability of the modelling approach to describe polydisperse bubbly flows.
Novel association between microglia and stem cells in human gliomas: A contributor to tumour proliferation?
Authors: Noorani Imran , Petty Gareth , Grundy Paul L , Sharpe Geoff , Willaime‐Morawek Sandrine , Harris Scott , Thomas Gareth J , Nicoll James AR , Boche Delphine 
Published: October 2014

AbstractBrain tumour stem cells and microglia both promote the growth of astrocytomas, the commonest form of primary brain tumour, with recent emerging evidence that these cell types may interact in glioma models. It is unclear whether microglia and stem cells are associated in human gliomas. To investigate this question, we used the technique of tissue microarrays to perform a correlative study of a large number of tumour samples. We quantified immunostaining of human astrocytic tumour tissue microarrays (86 patients; World Health Organisation grade II–IV) for microglia Ionized calcium binding adaptor molecule 1 (Iba1) and CD68, and stem cell nestin, SOX2 and CD133. Ki67 was used to assess proliferation and GFAP for astrocytic differentiation. Immunoreactivity for both microglial markers and stem cell markers nestin and SOX2 significantly increased with increasing tumour grade. GFAP was higher in low grade astrocytomas. There was a positive correlation between: (i) both microglial markers and nestin and CD133, (ii) nestin and tumour cell proliferation Ki67 and (iii) both microglial markers and Ki67. SOX2 was not associated with microglia or tumour proliferation. To test the clinical relevance, we investigated the putative association of these markers with clinical outcomes. High expression for nestin and Iba1 correlated with significantly shorter survival times, and high expression for nestin, Iba1, CD68 and Ki67 was associated with faster tumour progression on univariate analysis. On multivariate analysis, nestin, CD133 and Ki67 remained significant predictors of poorer survival, after adjustment for other markers. These results confirm previous in vitro findings, demonstrating their functional relevance as a therapeutic target in humans. This is the first report of a novel correlation between microglia and stem cells that may drive human astrocytic tumour development.