bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of poly(ethylene terephthalate) waste bottles in the presence of dual functional phase transfer catalysts
Authors: Zhang Lirong , Gao Jie , Zou Jianzhong , Yi Fengping 
Published: June 2013

ABSTRACTThe hydrolysis of poly(ethylene terephthalate) (PET) obtained from waste bottles was studied. The dual functional phase transfer catalyst [(CH3)3N(C16H33)]3[PW12O40] exhibited outstanding catalytic activity to the hydrolysis of PET. Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy were used to confirm the main product terephthalic acid (TPA) of hydrolysis. The effects of temperature, time, particle size of PET and dosage of catalyst on hydrolysis reaction were examined. Under the optimum conditions of reaction temperature 145°C, time 2 h, particle size of PET at 0.5–1 mm and dosage of catalyst at 7 wt %, the conversion of PET and the yield of TPA were almost 100% and 93%, respectively. After easily separated from the product, the catalyst could be reused more than three times without obvious decrease in the conversion of PET and yield of TPA. An economical and convenient process was developed for hydrolysis of PET. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2790–2795, 2013
Zur Erweiterung der grafischen Statik in die 3. Dimension
Authors: Schrems Maximilian , Kotnik Toni 
Published: June 2013

AbstractIm 19. Jahrhundert wurden grafische Methoden – 1866 von Carl Culmann als “Graphische Statik” systematisiert und publiziert – dazu benutzt, den Zusammenhang zwischen geometrischer Form und innerem Kräftefluss genauer zu untersuchen. Diese Methoden wurden mehr und mehr durch analytische Verfahren ersetzt, da in den aufstrebenden Ingenieurwissenschaften die leichter zu verarbeitende numerische Berechnung, in Kombination mit physikalischen Experimenten, an Bedeutung gewann, wodurch ein Bedürfnis nach numerischer “Präzision” bestand. Heutzutage können mithilfe von digitalen Werkzeugen auch komplexe dreidimensionale Geometrien dargestellt werden und somit taucht in der Architektur wieder das Interesse an der grafischen Statik auf. Dieses Interesse gründet auf der einfachen und mathematisch präzisen Herangehensweise der grafischen Statik, mit deren Hilfe der Zusammenhang von Kraft und Form diskutiert werden kann. Die laufende Forschung an der ETH Zürich zur Erweiterung der grafischen Statik in die 3. Dimension hat einerseits das Ziel, Limitierungen des zweidimensionalen Culmann'schen Ansatzes zu überwinden, andererseits eine vektorgeometrische, visuelle und damit synthetische Methode zur Untersuchung von dreidimensionalen Kräfteflüssen zu generieren. Dabei ist wichtig, dass der Fokus auf der Betrachtung der Resultierenden und der Erforschung von deren Enstprechung im Raum liegt.On the extension of graphical statics into the 3rd dimensionIn the 19th century methods of graphical statics – systematized and published by Carl Culmann in 1866 – were used to study in more detail the relationship between form and the flow of forces. Historically, they were superseded by analytical methods, due to the relative ease of numerical calculations and the increasing importance of experimentation by the developing discipline of engineering with its need for precision. Nowadays, however, with the availability of digital tools and the possibility of visualization of geometry in 3D space, there is a re‐emerging interest in graphic statics within the design process. Therefore, a visual dialogue about the flow of forces based on graphic statics should be fostered because these methods offer a simple yet precise way to discuss the geometrical dependency of form and forces. The research is part of an ongoing process to extend the methods of graphic statics to the third dimension in order to overcome, on the one hand, some of the limitations of Culmann's approach and on the other, to generate a geometrical, visual and thus synthetic method for exploring 3D equilibrium. The focus is on the resultant and on the likeness in space.
Fallstudie zur seismischen Auslegung der Stationen und der Tunnel einer U‐Bahnlinie in weichem Boden
Authors: Vrettos Christos , Chen Dong , Rizos Dimitris 
Published: June 2013

AbstractDie seismische Auslegung von unterirdischen Bauwerken wird durch Verformung des Bodens und die Boden‐Bauwerk‐Interaktion gesteuert, wobei die kinematischen Effekte gegenüber den Trägheitseffekten dominieren. Verfügbare Methoden der numerischen Berechnung für die 2D‐Antwort in Querrichtung werden für eine Fallstudie, welche die Stationen und die Tunnelröhren einer U‐Bahnlinie in einem Erdbebengebiet betrifft, angewandt. Zwei Kontinuum‐Ansätze werden betrachtet: a) dynamische Finite‐Elemente‐Methode im Zeitbereich und b) quasi‐statische Methode. Schnittkräfte in den Bauwerken werden für ein typisches Erdbeben bestimmt, sie werden gegenübergestellt und mit Ergebnissen aus der statischen Berechnung der Baugrube und der Tunnelröhren verglichen.Case study on the seismic design of the stations and the tunnels of a subway line in soft groundThe seismic design of underground structures is controlled by ground deformation and soil‐structure interaction, whereby kinematic effects dominate over inertia effects. Available methods of numerical analysis for the 2D response in the transverse direction are applied for a case study referring to the stations and the inter‐station tunnels of a metro‐line in a seismic region. Two continuum approaches are considered: a) time‐domain dynamic finite‐element and b) quasi‐static analyses. Sectional forces are determined for a typical earthquake shaking. They are compared against each other and to those obtained from the static design of the excavation support.
Die neue indische Antarktis‐Forschungsstation
Authors: Brunn Benjamin , Nitschke Andreas , Schramm Thomas 
Published: June 2013

AbstractDie erste Herausforderung dieses außergewöhnlichen Projektes bestand im Zusammenführen aller Beteiligten: Den indischen Bauherrn, die norwegischen und deutschen Baufirmen und die Autoren als Generalplaner sowie Bauüberwacher und Kopf eines Teams mit zwei Sub‐Planern für Architektur und Haustechnik. Die zweite Herausforderung war die Antarktis. Planungsgrundlagen, die sonst aus Normen entnommen werden können, mussten zunächst ermittelt werden, z.B. Wind‐ und Schneelasten sowie Eisbedingungen. Alle Materialien mussten für den Einsatz im antarktischen Klima geeignet sein. Eine dritte Herausforderung war die Logistik. Alle Komponenten mussten in 20‐Fuß‐Container passen, die für Hubschraubertransporte nicht zu schwer sein durften. Der Zeitraum für den Bau während des antarktischen Sommers ist sehr kurz. Alle Randbedingungen spiegeln sich im Gebäude wider. Form und Materialien sind auf Ort, Klima und Logistik abgestimmt. Das dreigeschossige Containergebäude mit 52 m Länge und 30 m Breite kann 47 Personen beherbergen und enthält Labore, eine Garage, eine Werkstatt, Wohn‐ und Büroräume, ein Kino, einen Sportraum, eine Bibliothek, einen Speiseraum und einen Salon mit Blick über das Meer. Dieses durch die indische Regierung veranlasste Projekt eines hochmodernen Gebäudes konnte erfolgreich durch eine enge Zusammenarbeit internationaler Teilnehmer sowie deren Leidenschaft für das gemeinsame Ziel, dem gegenseitigen Vertrauen zueinander und dem Respekt voreinander und vor der Natur realisiert werden.New Indian Research Station at Larsemann Hills, AntarcticaThe first challenge of this extraordinary project was the integration of all involved parties: The Indian client, the Norwegian and German construction companies and the authors as general planners and site supervisors being head of a team with two sub‐consultants for architecture and building services. The second challenge was Antarctica. Planning bases usually taken from standards had to be ascertained, e.g. wind loads, snow and ice conditions. All materials needed to be suitable for Antarctic climate conditions. A third challenge was the logistics. All components had to fit into 20‐foot containers, which in turn required being light enough for helicopter transport. The time frame for construction during the Antarctic summer is short. All boundary conditions are reflected in the building; form and material are suited for the location, climate and logistics. The three‐storey container building, which is 52 m long and 30 m wide, can accommodate 47 people and contains laboratories, a garage, workshop, living and office areas, a cinema, fitness room, library, dining hall and lounge with a view of the ocean. The Indian government initiated this state‐of‐the‐art project, which was successfully completed through the co‐operation of international participants with passion, faith and respect for each other and nature.
Deutschlands älteste Betonbrücken
Authors: Veihelmann Karen , Holzer Stefan M. 
Published: June 2013

AbstractDie Wurzeln des modernen Betonbaus werden in der Literatur meist stiefmütterlich behandelt. Über einige Eckdaten, die von Publikation zu Publikation kopiert werden, gehen die Vorbemerkungen meist nicht hinaus. Im Rahmen eines Forschungsprojektes an der Universität der Bundeswehr in München/Neubiberg wird durch die Autoren diese Frühzeit genauer beleuchtet. Im Zuge der Arbeiten konnte Deutschlands älteste Betonbrücke ausfindig gemacht werden: Die Brücke über die Lenne bei Vorwohle. Die Brücke, deren Tragwerk bis heute nahezu unbeschädigt erhalten ist, wird nachfolgend beschrieben und in den Zusammenhang mit zwei beinahe bauzeitgleichen Schwesterbauwerken gestellt.Germany's first concrete bridgesThe early history of unreinforced concrete has received little attention until now. However, significant engineering concrete structures have been constructed long before the advent of reinforced concrete in bridge building at the end of the 19th century. In this short notice, the authors present three small arch bridges dating back to 1877/1878 which are probably Germany's oldest concrete bridges.
Is LMNB1 a susceptibility gene for neural tube defects in humans?
Authors: Robinson Alexis , Partridge Darren , Malhas Ashraf , De Castro Sandra C.P. , Gustavsson Peter , Thompson Dominic N. , Vaux David J. , Copp Andrew J. , Stanier Philip , Bassuk Alexander G. , Greene Nicholas D.E. 
Published: June 2013

BACKGROUNDLamins are intermediate filament proteins that form a major component of the nuclear lamina, a protein complex at the surface of the inner nuclear membrane. Numerous clinically diverse conditions, termed laminopathies, have been found to result from mutation of LMNA. In contrast, coding or loss of function mutations of LMNB1, encoding lamin B1, have not been identified in human disease. In mice, polymorphism in Lmnb1 has been shown to modify risk of neural tube defects (NTDs), malformations of the central nervous system that result from incomplete closure of the neural folds.METHODSMutation analysis by DNA sequencing was performed on all exons of LMNB1 in 239 samples from patients with NTDs from the United Kingdom, Sweden, and United States. Possible functional effects of missense variants were analyzed by bioinformatics prediction and fluorescence in photobleaching.RESULTSIn NTD patients, we identified two unique missense variants that were predicted to disrupt protein structure/function and represent putative contributory mutations. Fluorescence loss in photobleaching analysis showed that the A436T variant compromised stability of lamin B1 interaction within the lamina.CONCLUSIONThe genetic basis of human NTDs appears highly heterogenous with possible involvement of multiple predisposing genes. We hypothesize that rare variants of LMNB1 may contribute to susceptibility to NTDs. Birth Defects Research (Part A) 97:398–402, 2013. © 2013 Wiley Periodicals, Inc.
Werkstoffgerechtes Konstruieren mit Hochleistungsbetonen
Authors: Schnell Jürgen , Kohlmeyer Christian , Bayer Dirk , Müller Frank 
Published: June 2013

AbstractHochleistungsbetone eröffnen neue Möglichkeiten für Gestaltung und Konstruktion. Der Beitrag schildert an der TU Kaiserslautern verfolgte Ansätze zu einem möglichst werkstoffgerechten Umgang mit diesem Material am Beispiel filigraner Bauteile mit angepassten Bewehrungs‐ und Fügetechniken.Ein Ansporn für die fortwährende Suche nach neuen ingenieurtechnischen Lösungen, die auch gestalterische Optionen eröffnen, sind die unzähligen Entwürfe, mit denen Werner Sobek dem intelligenten und multifunktionalen Einsatz verschiedenster Materialien in oft hybrider Kombination im Bauwesen weltweit den Weg bereitet hat.High‐performance concretes open up new possibilities for design and constructionThis paper depicts the approaches pursued at the TU Kaiserslautern in order to facilitate an appropriate dealing with this material exemplified by filigree components with customized reinforcement and joining techniques.An incentive for the continuous search for new technical solutions, that open up also creative options, are the countless designs with which Werner Sobek has paved worldwide the way for intelligent and multifunctional use of different materials in often hybrid combination in the construction industry.
Tragverhalten biege‐ und querkraftbeanspruchter Bauteile aus funktional gradiertem Beton
Authors: Herrmann Michael , Haase Walter 
Published: June 2013

AbstractDie Gradierung von Betonbauteilen ermöglicht eine Anpassung des Bauteilinneren an das vorherrschende statische oder bauphysikalische Anforderungsprofil. Durch eine in bis zu drei Raumrichtungen kontinuierlich frei veränderbare Porosität lassen sich maßgeschneiderte Betonbauteile herstellen. Um das Potenzial der neuen Bauweise erschließen zu können, müssen das Tragverhalten untersucht und Bemessungsansätze entwickelt werden.Nachfolgend werden die verwendeten Nachweise und die getroffenen Annahmen zur Auslegung von Bauteilen aus gradiertem Beton beschrieben. Der Einfluss des Gradientenlayouts und der verwendeten Bewehrungsmaterialien auf das Biegetragverhalten wurde in Bauteilversuchen ermittelt. Die Querkrafttragfähigkeit wurde in Abhängigkeit der Schubschlankeit untersucht und der Vergleich zur rechnerischen Tragfähigkeit nach Norm gezogen. Der vorliegende Aufsatz soll somit einen Beitrag zum Verständnis der Besonderheiten im Tragverhalten gradierter Betonbauteile darstellen.Load bearing behaviour of functionally graded concrete components under flexural and shear stressThe grading of concrete components enables the adaptation of the internal material distribution according to static demands and requirements related to building physics. Customized elements can be fabricated by changing the concrete porosity continuously in three dimensions. In order to utilize the potential of this new construction method, the load bearing behaviour needs to be investigated and design methods need to be developed.The following describes the analyses and assumptions that were applied for the design of graded concrete elements. The influence of the gradient layout and of the reinforcement type on the flexural load bearing behaviour was determined experimentally. The shear capacity was investigated as a function of the shear slenderness ratio and compared to the design values computed according to the national code. The present article is intended to aid the understanding of the specific characteristics of the load bearing behaviour of functionally graded concrete elements.
Chemistry and Biology of the Potent Endotoxin from a Burkholderia dolosa Clinical Isolate from a Cystic Fibrosis Patient
Authors: Lorenzo Flaviana Di , Sturiale Luisa , Palmigiano Angelo , Fazio Luigi Lembo‐ , Paciello Ida , Coutinho Carla P. , Sá‐Correia Isabel , Bernardini MariaLina , Lanzetta Rosa , Garozzo Domenico , Silipo Alba , Molinaro Antonio 
Published: June 2013

AbstractThis is the first report of the chemical and biological properties of the lipooligosaccharide (LOS) endotoxin isolated from Burkholderia dolosa IST4208, an isolate recovered from a cystic fibrosis (CF) patient in a Portuguese CF center. B. dolosa is a member of the Burkholderia cepacia complex, a group of closely related species that are highly problematic and opportunistic pathogens in CF. B. dolosa infection leads to accelerated loss of lung function and decreased survival. The structural determination of its endotoxin was achieved using a combination of chemistry and spectroscopy, and has revealed a novel endotoxin structure. The purified LOS was tested for its immunostimulatory activity on human HEK 293 cells expressing TLR‐4, MD‐2, and CD‐14. In these assays, the LOS showed strong proinflammatory activity.
Recyclable Catalyst Reservoir: Oxidation of Alcohols Mediated by Noncovalently Supported Bis(imidazolium)‐Tagged 2,2,6,6‐Tetramethylpiperidine 1‐Oxyl
Authors: Beejapur Hazi Ahmad , Giacalone Francesco , Noto Renato , Franchi Paola , Lucarini Marco , Gruttadauria Michelangelo 
Published: June 2013

AbstractBis(imidazolium)‐tagged 2,2,6,6‐tetramethylpiperidine 1‐oxyl (TEMPO) catalysts were adsorbed on different supports such as silica gel, silica gel modified with highly cross‐linked polymeric imidazolium networks, and highly cross‐linked polymeric imidazolium networks entrapping magnetic particles. These systems provided a convenient tool for the oxidation of both primary and secondary alcohols working as recyclable reservoirs for the bis(imidazolium)‐tagged TEMPO catalysts. By using EPR spectroscopy it was demonstrated that the catalyst was released as the corresponding oxoammonium salt in the solution during the recycling step, thus promoting the oxidative process in a homogeneous fashion. After solvent removal, the catalyst was readsorbed on the support allowing an easy recovery and recycle of the catalytic material up to 13 consecutive cycles with no loss in activity. The bis(imidazolium)‐tagged TEMPO catalyst could be used in only 1 mol % both for the oxidation of benzylic and aliphatic alcohols. The catalytic material was highly recyclable if used on silica or imidazolium‐modified silica gel in 10 mol % loading. Loading could be scaled down to 1 mol % and the catalyst proved to be recyclable up to 8 cycles only with imidazolium‐modified silica gel. Such a “catalyst‐sponge‐like” system permits to combine the benefits of homogeneous and heterogeneous catalysis.
Photocatalytic Hydrogen Evolution with a Self‐Assembling Reductant–Sensitizer–Catalyst System
Authors: Natali Mirco , Argazzi Roberto , Chiorboli Claudio , Iengo Elisabetta , Scandola Franco 
Published: June 2013

AbstractA noble‐metal‐free system for photochemical hydrogen production is described, based on ascorbic acid as sacrificial donor, aluminium pyridyl porphyrin as photosensitizer, and cobaloxime as catalyst. Although the aluminium porphyrin platform has docking sites for both the sacrificial donor and the catalyst, the resulting associated species are essentially inactive because of fast unimolecular reversible electron‐transfer quenching. Rather, the photochemically active species is the fraction of sensitizer present, in the aqueous/organic solvent used for hydrogen evolution, as free species. As shown by nanosecond laser flash photolysis experiments, its long‐lived triplet state reacts bimolecularly with the ascorbate donor, and the reduced sensitizer thus formed, subsequently reacts with the cobaloxime catalyst, thereby triggering the hydrogen evolution process. The performance is good, particularly in terms of turnover frequencies (TOF=10.8 or 3.6 min−1, relative to the sensitizer or the catalyst, respectively) and the quantum yield (Φ=4.6 %, that is, 9.2 % of maximum possible value). At high sacrificial donor concentration, the maximum turnover number (TON=352 or 117, relative to the sensitizer or the catalyst, respectively) is eventually limited by hydrogenation of both sensitizer (chlorin formation) and catalyst.
Biomimetic Ion Nanochannels as a Highly Selective Sequential Sensor for Zinc Ions Followed by Phosphate Anions
Authors: Han Cuiping , Su Haiyan , Sun Zhongyue , Wen Long , Tian Demei , Xu Kai , Hu Junfeng , Wang Aming , Li Haibing , Jiang Lei 
Published: June 2013

AbstractA novel biomimetic ion‐responsive multi‐nanochannel system is constructed by covalently immobilizing a metal‐chelating ligand, 2,2′‐dipicolylamine (DPA), in polyporous nanochannels prepared in a polymeric membrane. The DPA‐modified multi‐nanochannels show specific recognition of zinc ions over other common metal ions, and the zinc‐ion‐chelated nanochannels can be used as secondary sensors for HPO42− anions. The immobilized DPA molecules act as specific‐receptor binding sites for zinc ions, which leads to the highly selective zinc‐ion response through monitoring of ionic current signatures. The chelated zinc ions can be used as secondary recognition elements for the capture of HPO42− anions, thereby fabricating a sensing nanodevice for HPO42− anions. The success of the DPA immobilization and ion‐responsive events is confirmed by measurement of the X‐ray photoelectron spectroscopy (XPS), contact angle (CA), and current–voltage (I–V) characteristics of the systems. The proposed nanochannel sensing devices display remarkable specificity, high sensitivity, and wide dynamic range. In addition, control experiments performed in complex matrices suggest that this sensing system has great potential applications in chemical sensing, biotechnology, and many other fields.
Ultrathin SnO2 Scaffolds for TiO2‐Based Heterojunction Photoanodes in Dye‐Sensitized Solar Cells: Oriented Charge Transport and Improved Light Scattering
Authors: Yang Shuang , Hou Yu , Xing Jun , Zhang Bo , Tian Feng , Yang Xiao Hua , Yang Hua Gui 
Published: June 2013

AbstractIn this paper, band‐structure matching strategy of a TiO2‐based heterojunction within which electrons can be collected from TiO2 nanoparticles and transported rapidly in the bulk structure is reported. On the basis of the band‐structure analysis of different TiO2‐based heterostructures, focus was directed to the SnO2 nanosheet because of its appropriate band position and high electrical conductivity. Through a systematic investigation of the incorporation of ultrathin SnO2 nanosheet scaffolds for TiO2‐based photoanodes in dye‐sensitized solar cells (DSCs), we propose an anisotropy “constrained random walk” model to describe the controlled electron transit process. In this system, electrons are transferred orientedly overall, as well as randomly locally, leading to a significant reduction in the charge diffusion route compared to the conventional isotropic “random walk” model. In brief, the 2D ultrathin nanosheets provide rapid transit pathways and improved light‐scattering centers, which can ensure a sufficient amount of dye loading and slow recombination. An overall light‐to‐electricity conversion efficiency as high as 8.25 % is achieved by embedding the appropriate amount of SnO2 scaffold in a TiO2‐based photoanode.