bluuebunny/crossref_metadata_2025_split huggingface dataset:
Entwicklung eines brandbeständigen ultrahochfesten Betons für hochdynamische Beanspruchungen
Authors: Scheydt Jennifer C. , Millon Oliver , Müller Harald S. , Thoma Klaus 
Published: May 2012

AbstractSeit einigen Jahren setzt sich die Bundesregierung verstärkt mit den Auswirkungen extremer Ereignisse wie Naturkatastrophen, technische Großunfälle und insbesondere auch Terroranschläge auseinander. Infolgedessen wurde im Jahr 2007 das Programm “Forschung für die zivile Sicherheit” durch das Bundesministerium für Bildung und Forschung (BMBF) ins Leben gerufen. Hierin sollten Lösungen für den Umgang mit derartigen Bedrohungsszenarien gesucht werden.Ein besonderes Gefährdungspotenzial besteht hierbei für Infrastrukturen des öffentlichen Verkehrs wie Tunnel oder Brücken, deren Ausfall schwere Folgen für die Versorgung der Bevölkerung haben kann. Um für den Fall der Extrembeanspruchung derartiger Infrastrukturbauwerke den größtmöglichen Schutz zu gewährleisten, muss die Tragfähigkeit der baulichen Strukturen verbessert werden. Das Forschungsvorhaben AISIS hat sich im Rahmen dessen mit der Entwicklung eines brandbeständigen ultrahochfesten Betons für hochdynamische Beanspruchungen befasst. Die erzielten Forschungsergebnisse sind nachfolgend dargelegt.Development of an ultra high strength concrete with increased resistance to fire and explosive loadingIn recent years, the German Government exceedingly deals with the consequences of extreme events such as natural disasters, technical accidents and terrorist attacks. In 2007, the program “Research for Civil Security” was set up by the German Federal Ministry of Education and Research (BMBF) which aimed at solutions for the handling of such menaces.Particularly the breakdown of public transport buildings (e. g. tunnels, bridges) is supposed to involve a drastic undersupply of general public in case of attack. To avoid that, the load bearing capacity of these buildings has to be enhanced. In this context, an ultra high strength concrete with increased resistance to fire and explosive loading was developed within the research project AISIS. The project results are presented within this article.
vKASS: a surgical procedure simulation system for arthroscopic anterior cruciate ligament reconstruction
Authors: Wang Yanzhen , Xiong Yueshan , Xu Kai , Liu Dong 
Published: May 2012

ABSTRACTArthroscopic surgeries, which are widely used for anterior cruciate ligament (ACL) reconstruction, not only require advanced hand–eye coordination but also involve complicated surgical procedure, necessitating simulation‐based training for surgeons. This paper describes a surgical procedure simulation system for the training of arthroscopic ACL reconstruction. Different from existing simulation‐based training systems for basic surgical skills, this system provides a complete simulation for the entire procedure of arthroscopic ACL reconstruction, involving operations such as puncturing, probing, incision, and drilling. In this system, we employ a linear elastic finite element method and position‐based dynamics for deformable modeling. Simplified vertex duplicating method and an implementation of real‐time Boolean operations are proposed for the topological change of tissue models involved in the incision simulation and tunnel construction. Two specially designed force feedback models are introduced for the haptic rendering of probing and drilling operations. By using these fast and stable simulation methods, this system is able to provide real‐time realistic graphical and haptic feedback to the user, making it efficient and practical for training purpose. Feedback from the surgeon trainees shows that this system is very effective in training not only for basic surgical skills but also for the complex surgical procedure. Copyright © 2012 John Wiley & Sons, Ltd.
Suture‐mediated arterial access site closure after transfemoral aortic valve implantation
Authors: Kahlert Philipp , Al‐Rashid Fadi , Plicht Björn , Konorza Thomas , Neumann Till , Thielmann Matthias , Wendt Daniel , Erbel Raimund , Eggebrecht Holger 
Published: May 2012

ObjectivesTo evaluate feasibility, safety and efficacy of percutaneous arterial access site closure after transfemoral, transcatheter aortic valve implantation (TF‐TAVI) using a single, commercially available six French monofilament suture‐mediated vascular closure device (VCD) in “preclosure” technique.BackgroundCurrently, TF‐TAVI is evolving into a completely percutaneous procedure. However, percutaneous access site closure still remains a major technical challenge with room for improvement.Methods94 of 144 consecutive patients underwent completely percutaneous TF‐TAVI using following technique for access site closure: After puncture of the common femoral artery using fluoroscopy and contralateral angiography for guidance, the VCD was deployed prior further predilatation of the vessel and insertion of the large‐bore introducer sheath. At the end of the procedure, the preloaded sutures were tied for final hemostasis and crossover angiography was used for postprocedural evaluation of the access vessel.ResultsApplication of the VCD was technically successful in all cases, resulting in an efficient hemostasis with cessation of any bleeding within 10 min of final knot‐tying in 83 of the 94 patients, and there was only one closure‐failure with continuous bleeding despite prolonged manual compression requiring endovascular treatment. In addition, we observed four closure‐related access vessel stenoses of hemodynamic relevance requiring endovascular treatment in three and surgical repair in one patient. However, interventional and surgical repair was not associated with death or irreversible end‐organ damage and all patients recovered without sequelae.Conclusion“Preclosure” of the arterial access site with a single six French suture‐mediated VCD is relatively easy, safe and efficient method for access site closure after TF‐TAVI which, along with ongoing profile reductions of TAVI devices, should further simplify and broaden the way toward a routine, completely percutaneous procedure. © 2012 Wiley Periodicals, Inc.
A Liquid–Liquid Biphasic Homogeneous Organocatalytic Aldol Protocol Based on the Use of a Silica Gel Bound Multilayered Ionic Liquid Phase
Authors: Montroni Elisa , Lombardo Marco , Quintavalla Arianna , Trombini Claudio , Gruttadauria Michelangelo , Giacalone Francesco 
Published: May 2012

AbstractAn innovative two stage liquid–liquid biphasic homogeneous protocol for the asymmetric organocatalytic aldol reaction is proposed, based on the use of the cis‐ion‐tagged proline 8 dissolved in the liquid film of a multilayered ionic liquid covalently bonded to silica gel 4. The resulting catalytically active material 9 is first soaked with cyclohexanone in the presence of water, resulting in a semi‐transparent gel, then the aldehyde is added and the mixture stirred at RT. In the first stage, 4 acts as a catalyst reservoir that delivers 8 to the cyclohexanone phase allowing the reaction to take place homogeneously. In the second stage, cyclohexanone is removed under vacuum and the resulting slurry is extracted with anhydrous diethylether. Now 4 acts as a catalyst sponge, redissolving 8. Product extraction is extremely selective; no trace of catalyst is detected in the product‐containing phase, and 9 can be easily reused several times with high cumulative productivity values (up to 523).
Surface and Bulk Approach to Time‐resolved Characterization of Heterogeneous Catalysts
Authors: Kubacka Anna , Iglesias‐Juez Ana , Martínez‐Arias Arturo , Di Michiel Marco , Newton Mark A. , Fernández‐García Marcos 
Published: May 2012

AbstractThe evolution of time‐resolved experiments, covering a multipurpose surface and bulk characterization of catalytic solids, during their preparation process and under reaction conditions, is presented. Particular emphasis is given to recent studies that attempt to unveil contemporary unresolved questions concerning the control of physicochemical properties of nanosolids, as well as the evolution of such solid materials under reactive atmospheres. To reach this goal, representative in situ and in operando works, using either modern (mostly synchrotron radiation based) approaches or multi‐technique methods (mainly, although not exclusively, X‐ray–vibrational coupling), and considering experiments in liquid and gas phase, as well as with amorphous, nanocrystalline and surface‐deposited materials, are reviewed.
Heterotermetallic Indium Lithium Halostannates: Low‐Temperature Single‐Source Precursors for Tin‐Rich Indium Tin Oxides and Their Application for Thin‐Film Transistors
Authors: Samedov Kerim , Aksu Yilmaz , Driess Matthias 
Published: May 2012

AbstractThe syntheses and structural elucidation of dimeric [Sn(OCyHex)2] (1), its corresponding (cyclohexoxy)alkalistannates(II) [{M(OCyHex)3Sn}2] (M=Li (2), Na (3), K (4)), and of the first heteroleptic heterotermetallic Li/In/Sn–haloalkoxide clusters [X2In{LiSn2(OCyHex)6}] (X=Br (5), Cl (6)) with a double seco‐norcubane core are reported. They represent suitable precursors for new amorphous indium tin oxide (ITO) materials as transparent conducting oxides with drastically reduced concentrations of expensive indium, while maintaining their high electrical performance. In fact, compounds 5 and 6 were successfully degraded under dry synthetic air at relatively low temperature, resulting in new semiconducting tin‐rich ITOs homogeneously dispersed in a tin oxide/lithium oxide matrix. The obtained particles were investigated and characterised by different analytical techniques, such as powder XRD, IR spectroscopy, SEM, TEM and energy‐dispersive X‐ray spectroscopy (EDX). The analytical data confirm that the final materials consist of tin‐containing indium oxide embedded in an amorphous tin oxide matrix. The typical broadening and shift of the observed indium oxide reflections to higher 2θ values in the powder XRD pattern clearly indicated that tin centres were successfully incorporated into the In2O3 lattice and partially occupied In3+ sites. Investigations by EDX mapping proved that Sn was homogeneously distributed in the final materials. Thin‐film field‐effect transistors (FETs) were fabricated by spin‐coating of silicon wafers with solutions of 5 in toluene and subsequent calcination under dry air (25–700 °C). The FETs prepared with precursor 5 exhibited excellent performances, as shown by a charge‐carrier mobility of 6.36×10−1 cm2 V−1 s (calcination at 250 °C) and an on/off current ratio of 106.
Determination of barriers to rotation of axially chiral 5‐methyl‐2‐(o‐aryl)imino‐3‐(o‐aryl)thiazolidine‐4‐ones
Authors: Erol Sule , Dogan Ilknur 
Published: May 2012

ABSTRACTThermally interconvertible axially chiral 5‐methyl‐2‐(o‐aryl)imino‐3‐(o‐aryl)‐thiazolidine‐4‐ones have been synthesized diastereoselectively, and conformations of the major and minor enantiomeric pairs have been determined by 1H nuclear magnetic resonance. Chromatographic resolutions of each compound have been performed by enantioselective high‐performance liquid chromatography, and the barriers to rotation about the N3‐Caryl bond have been determined by following the thermal interconversion process of the major to minor isomers until equilibrium. The rotational barriers range from 96.2 to 115.2 kJ/mol, depending on the size of ortho substituent on N3‐aryl ring. Chirality 24:493–498, 2012. © 2012 Wiley Periodicals, Inc.
Vortex motion‐based particle swarm optimisation for energy consumption of alumina evaporation
Authors: Zhu Hongqiu , Chai Qinqin , Yang Chunhua , Wang Xiaoli 
Published: May 2012

AbstractThe aim of the alumina evaporation process is to improve the concentration of sodium aluminate solution by evaporating the excess water contained in the solution. The evaporation is achieved using heat from steam. Since steam consumption is the major operating costs, in this paper, we investigate an operation optimisation problem for the evaporation process to minimise steam consumption subject to a constraint on the particular quality of the final sodium aluminate solution. This paper proposes a new particle swarm optimisation (PSO) algorithm based on vortex motion to solve this optimisation problem. We demonstrate the effectiveness of the PSO algorithm on benchmark functions. We then apply it to a real industrial evaporation process, where the optimal results show that the steam consumption is considerably reduced. © 2012 Canadian Society for Chemical Engineering
Distribution of soap in a membrane reactor in the production of fame from waste cooking oil
Authors: Hasswa Raghda , Dubé Marc A. , Tremblay André Y. 
Published: May 2012

AbstractA continuous‐flow membrane reactor was constructed for the production of fatty acid methyl ester (FAME) from waste vegetable oil with high free fatty acid (FFA) content. FAME was produced via base‐catalysed transesterification with methanol at two FFA levels: 4.8 and 10 mass%. The effect of the ceramic membrane pore size on the separation of soap and triglycerides from the FAME in the reactor was investigated. In all cases, the triglyceride was completely retained in the reactor, yielding free and total glycerine contents in the produced FAME significantly below the maximum limits of the ASTM D6751 standard. The soaps produced in the reaction mixture were not completely retained in the reactor and did not affect the FAME production process. © 2012 Canadian Society for Chemical Engineering
Modelling carbon dioxide solubility in ionic liquids
Authors: Mortazavi‐Manesh Soheil , Satyro Marco , Marriott Robert A. 
Published: May 2012

AbstractSolubility information for CO2 in different ionic liquids, ILs, in part can potentially be used to select a specific IL for the separation of CO2 from hydrocarbon fluids. Unfortunately, not all CO2–IL systems have been experimentally described at similar temperatures and pressures; therefore, a direct comparison of performance by process simulation is not always possible. In the extreme cases, the design of a CO2 separation process may require predicting the CO2–IL equilibria for which there are no available solubility data. To address the need for this information, a semi‐empirical correlation was developed to estimate the dissolution of CO2 in CO2–IL solvent systems. The theoretical COSMO–RS calculation method was used to calculate the chemical potential of CO2 in a wide variety of ILs and the Soave–Redlich–Kwong equation was used to calculate the fugacity coefficient of the CO2 vapour phase. The model was correlated with available literature data, yielding an average error of AAR = 23% and small bias. © 2012 Canadian Society for Chemical Engineering
Reaction kinetics of 2‐((2‐aminoethyl) amino) ethanol in aqueous and non‐aqueous solutions using the stopped‐flow technique
Authors: Rayer Aravind V. , Henni Amr , Li Juelin 
Published: May 2012

AbstractObserved pseudo‐first‐order rate constants (ko) for the reaction between CO2 and 2‐((2‐aminoethyl) amino) ethanol (AEEA) were measured using the stopped‐flow technique in an aqueous system at 298, 303, 308 and 313 K, and in non‐aqueous systems of methanol and ethanol at 293, 298, 303 and 308 K. Alkanolamine concentrations ranged from 9.93 to 80.29 mol m−3 for the aqueous system, 29.99–88.3 mol m−3 for methanol and 44.17–99.28 mol m−3 for ethanol. Experimentally obtained rate constants were correlated with two mechanisms. For both the aqueous‐ and non‐aqueous‐AEEA systems, the zwitterion mechanism with a fast deprotonation step correlated the data well as assessed by the reported statistical analysis. As expected, the reaction rate of CO2 in the aqueous‐AEEA system was found to be much faster than in methanol or ethanol. Compared to other promising amines and diamines studied using the stopped‐flow apparatus, the pseudo‐first‐order reaction rate constants were found to obey the following order: PZ (cyclic‐diamine) > EDA (diamine) > AEEA (diamine) > 3‐AP (primary amine) > MEA (primary amine) > EEA (primary amine) > MO (cyclic‐amine). The reaction rate constant of CO2 in aqueous‐AEEA was double that in aqueous‐MEA, and the difference increased with an increase in concentration. All reaction orders were practically unity. With a higher capacity for carbon dioxide and a higher reaction rate, AEEA could have been a good substitute to MEA if not for its high thermal degradation. AEEA kinetic behaviour is still of interest as a degradation product of MEA. © 2012 Canadian Society for Chemical Engineering
Adsorption microcalorimetry applied to the characterisation of adsorbents for CO2 capture
Authors: da Silva F. Wilton Miranda , Maia Débora A. Soares , Oliveira Ronan S. , Moreno‐Piraján Juan Carlos , Sapag Karim , Cavalcante Célio L. , Zgrablich Giorgio , Azevedo Diana C. S. 
Published: May 2012

AbstractThe present work presents the design, assembly and experimental validation of a microcalorimetric device coupled to a volumetric adsorption setup applied to the characterisation of adsorbents for carbon dioxide (CO2) capture. Three adsorbents were evaluated for CO2 adsorption at 273 K in the pressure range of vacuum to 101 kPa. The data for CO2 on zeolite 13X agreed well with the available data reported in the literature, thus validating the device, which also provided reproducible results with an activated carbon sample. For the amine‐modified zeolite, the differential enthalpy at lower coverage was increased by a factor of 1.7 as compared to the zeolite matrix. This points out to the potential of such technique to characterise heterogeneities introduced by amine impregnation. However, the adsorption uptake was decreased by factor of 2.7 at 101 kPa. This fact suggests that amino groups may be blocking some physisorption sites, leading to restricted chemisorption on the outer surface. Thus, the main novelty of this study is the simultaneous measurement of adsorption isotherms and respective differential enthalpy curves for amine‐impregnated adsorbents, which may be considered a fingerprint of the modified surface chemistry. This work has been carried out in the framework of a cooperation project between three South American universities and is part of the effort to develop and fully characterise adsorbent materials intended for CO2 capture. © 2012 Canadian Society for Chemical Engineering
Prediction of induction time for natural gas components during gas hydrate formation in the presence of kinetic hydrate inhibitors in a flow mini‐loop apparatus
Authors: Talaghat Mohammad Reza 
Published: May 2012

AbstractThe objective of this work is the prediction of induction time (ti) for simple gas hydrate formation in the presence or absence of kinetic hydrate inhibitors at various conditions based on the Kashchiev and Firoozabadi model in a flow mini‐loop apparatus. For this purpose, the ti model is developed for simple gas hydrate formation in batch system for natural gas components during hydrate formation in a flow mini‐loop apparatus. A laboratory flow mini‐loop apparatus is designed and built up to measure the ti for simple gas hydrate formation when a hydrate former (such as C1, C3, CO2 and i‐C4) is contacted with water in the absence or presence of dissolved inhibitor, such as poly vinylpyrrolidone, PVCap and L‐tyrosine. In each experiment, a water blend saturated with pure gas is circulated up to a required pressure. Pressure is maintained at a constant value during experimental runs by means of the required gas make‐up. The average absolute deviation (AAD) of the predicted ti values from the corresponding experimental data are found to be about 11% and 9.4% for gas hydrate formation ti in the presence or absence of kinetic hydrate inhibitors, respectively. © 2012 Canadian Society for Chemical Engineering
Discovery, Synthesis, and in vitro Evaluation of West Nile Virus Protease Inhibitors Based on the 9,10‐Dihydro‐3H,4aH‐1,3,9,10a‐tetraazaphenanthren‐4‐one Scaffold
Authors: Samanta Sanjay , Cui Taian , Lam Yulin 
Published: May 2012

AbstractWest Nile virus (WNV), a member of the Flaviviridae family, is a mosquito‐borne pathogen that causes a great number of human infections each year. Neither vaccines nor antiviral therapies are currently available for human use. In this study, a WNV NS2B–NS3 protease inhibitor with a 9,10‐dihydro‐3H,4aH‐1,3,9,10a‐tetraazaphenanthren‐4‐one scaffold was identified by screening a small library of non‐peptidic compounds. This initial hit was optimized by solution‐phase synthesis and screening of a focused library of compounds bearing this scaffold. This led to the identification of a novel, uncompetitive inhibitor (1a40, IC50=5.41±0.45 μM) of WNV NS2B–NS3 protease. Molecular docking of this chiral compound onto the WNV protease indicates that the S enantiomer of 1a40 appears to interfere with the productive interactions between the NS2B cofactor and the NS3 protease domain; (S)‐1a40 is a preferred isomer for inhibition of WNV NS3 protease.
On the Configuration of Supercapacitors for Maximizing Electrochemical Performance
Authors: Zhang Jintao , Zhao X. S. 
Published: May 2012

AbstractSupercapacitors, which are attracting rapidly growing interest from both academia and industry, are important energy‐storage devices for acquiring sustainable energy. Recent years have seen a number of significant breakthroughs in the research and development of supercapacitors. The emergence of innovative electrode materials (e.g., graphene) has clearly provided great opportunities for advancing the science in the field of electrochemical energy storage. Conversely, smart configurations of electrode materials and new designs of supercapacitor devices have, in many cases, boosted the electrochemical performance of the materials. We attempt to summarize recent research progress towards the design and configuration of electrode materials to maximize supercapacitor performance in terms of energy density, power density, and cycle stability. With a brief description of the structure, energy‐storage mechanism, and electrode configuration of supercapacitor devices, the design and configuration of symmetric supercapacitors are discussed, followed by that of asymmetric and hybrid supercapacitors. Emphasis is placed on the rational design and configuration of supercapacitor electrodes to maximize the electrochemical performance of the device.
Dialkylimidazolium Ionic Liquids Hydrolyze Cellulose Under Mild Conditions
Authors: Gazit Oz M. , Katz Alexander 
Published: May 2012

AbstractThe average molecular weight of cellulose derived from filter paper, poplar, and Avicel decreases by up to two orders of magnitude during typical mild dissolution protocols using ionic liquids (ILs). About an order of magnitude greater cellulose depolymerization rate during ionic liquid dissolution occurs in 1‐butyl‐3‐methylimidazolium chloride (BmimCl) and 1‐ethyl‐3‐methylimidazolium chloride (EmimCl) compared to 1‐ethyl‐3‐methylimidazolium acetate (EmimOAc), and, unintuitively, greater IL purity results in greater cellulose depolymerization. The following data support the mechanism of cellulose hydrolysis to be acid‐catalyzed: (i) increase in number of reducing ends following cellulose dissolution in IL; (ii) addition of N‐methylimidazolium base suppresses cellulose depolymerization during dissolution in IL; (iii) small amounts of glucose and traces of hydroxymethyl furfural are present following cellulose dissolution in IL. The acid is presumably synthesized via IL decomposition to generate a carbene and proton, consistent with hypothesis derived from molecular modeling. Titration experiments conducted here measure the amount of acid synthesized to be in the 4000 ppm range for high‐purity BmimCl IL during mild processing conditions for cellulose dissolution. This data is relevant for understanding the extent of IL decomposition during biomass dissolution.