bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Measurement of Single Ionic Drift Velocities in Electrolyte Solutions. An NMR Method
Authors: Holz Manfred , Müller Christian 
Published: July 2012

AbstractThe theoretical and experimental principles of a novel method for the direct and rapid measurement of single ionic drift velocities in electrolytes are presented. The method is based on an NMR flow measuring technique and the velocity information is obtained through the observation of the spin‐echo amplitude in the presence of a pulsed magnetic field gradient and a pulsed electric field. It allows the determination of ionic mobilities and transference numbers in a more “direct” way than the classical electrochemical methods. First experimental results for (C2H5)4N+‐ions in aqueous solution are shown. Advantages, disadvantages and possible applications of this new NMR method in electrochemistry are discussed. It seems that the method has special advantages for measurements of electrical transport data in solutions of mixed electrolytes. The observation ot solvent motions in conducting electrolyte solutions could also be a possible application.
Mechanistic Studies on the Solvent Exchange at Co(II)‐Ions in Mixtures of Weak and Strong Donors
Authors: Dickert F. L. , Hellmann S. W. 
Published: July 2012

AbstractWith 1H and 31P NMR‐spectroscopy the solvation of Co(II)‐ions in mixtures of weak donors (methanol) and strong donors (dimethylformamide, hexamethylphosphoric acid triamide) was studied. In comparison with the complexes in the respective pure solvents, the ligand exchange rates of the strong donors are diminished and those of the weak donors are increased. These measurements yield information about the mechanism of the solvent exchange at metal ions and can be understood according to a donor‐acceptor model.
The Heats of Formation of Some Arsenates
Authors: Kubaschewski Oswald , Itagaki Kimio 
Published: July 2012

AbstractA recently constructed isoperibol calorimeter has been modified to measure the spontaneous reactions of Li2O, Na2O, CaO, and BaO with As2O5 after ignition. Thus, the heats of formation from the component oxides have been determined for Li3AsO4, Na3AsO4, Ca3As2O8, and Ba3As2O8.
Lasers in the Study of Elementary Processes
Authors: Smith Ian W. M. 
Published: July 2012

AbstractApplications of lasers in the kinetic study of elementary process are reviewed under three headings: (i) thermal rate constants, (ii) intermolecular and intramolecular energy transfer, and (iii) state‐to‐state reaction kinetics. The limitations, as well as the potential, of laser‐based techniques are illustrated and some areas of potential development are indicated.
Excess and Interaction Second Virial Coefficients for Ten Binary Gaseous Systems Containing SF6
Authors: Martin M. L. , Trengove R. D. , Harris K. R. , Dunlop Peter J. 
Published: July 2012

AbstractExcess and interaction second virial coefficients have been measured over the temperature range 290 – 320 K for binary systems of SF6 with He, Ne, Ar, Kr, Xe, N2, O2, CO2, CH4, and CF4. The excess virial coefficients are estimated to have an accuracy of 0.2 cm3 mol−1 and have been used to calculate molar excess enthalpies for each system at 300 K.
Lennard‐Jones (12,6) Parameters for the Non‐Ionic Contributions to Interionic Pairpotentials of Alkali Cations and Halide Anions from Crystal Data
Authors: Fischer Walter , Brickmann Jürgen 
Published: July 2012

AbstractLennard‐Jones (12,6) parameters for the pair interaction potentials of the alkali cations and halide anions were calculated on the basis of different alkali halide crystal data. Averaged values ϱ¯ and ϵ¯ were obtained by fitting the Buckingham type potential functions of Sangster and Dixon [15] for each individual alkali halide crystal. It was demonstrated, that these values can be used to predict unknown interaction potentials between unlike particles using the combination rules of Lorentz‐Berthelot [24] or those of Kong [18]. In particular it was shown, that the averaged parameters ϱ¯ and ϵ¯ lead to better results than the corresponding values originating from noble gas atoms.
Photocatalytic cis→trans‐Isomerization of Thioindigoid Dyes
Authors: Klages C. P. , Kobs K. , Memming R. 
Published: July 2012

AbstractThe trans‐isomers of certain thioindigoid dyes in dilute solutions can be completely converted to the cis‐isomer by selective excitation of the trans‐isomer. At higher dye concentrations the conversion is limited. The corresponding photostationary state is determined by two processes in opposite directions: (i) by the usual trans→cis photoisomerization and (ii) by an inverse cis→trans isomerization initiated by excitation of the trans‐isomer. An analysis of this peculiar effect has shown that the trans‐triplet catalyses the cis→trans‐isomerization.
Far Infrared Spectra of Strongly Polar Molecules in Solid Solution. II. Hydrogen Cyanide
Authors: Knözinger Erich , Wittenbeck Rüdiger 
Published: July 2012

AbstractFar infrared matrix isolation spectroscopy of hydrogen cyanide establishes the presence of monomers, linear dimers, and linear multimers in solid Ar. Information is obtained concerning the motion of monomer molecules relative to the cage as well as the intermolecular vibrational behaviour of the dimer. – The comparison with similar studies in the mid IR reveals the high potential of the application of far IR spectroscopy of matrix‐isolated samples to the investigation of association phenomena and intermolecular interactions.
Raman Spectra of Carbon Dioxide and Its Isotopic Variants in the Fermi Resonance Region: Part III. Analysis of Rovibrational Intensities for 12C16O2, 13C16O2, 12C18O2 and 12C16O18O
Authors: Finsterhölzl H. 
Published: July 2012

AbstractThe present work deals with the intensity analysis of rovibrationally resolved Raman spectra of natural and 13C as well as 18O isotopically enriched samples of CO2 photoelectrically recorded in the Fermi resonance region (1100–1460 cm−1). Based upon Chedin's set of rovibrational data [1] and upon the polarizability theory of Raman scattering, we have successfully fitted our calculated intensities to the measured spectra of each isotopic species. — The procedure yields values for three parameters, namely (δ2ƒ‐I0/δq2,+ ;δq2,‐) (δƒ‐I0/δq1) = ‐ 0.200 and ‐ 0.100 (± 3%) for t = 0 and t = 2, respectively, and |(δƒ‐00/& dgr;q1/δ ƒ‐20/δq1)| ≈ 1.47 ± 2%, that are derived from the spherical polarizability tensor ƒ‐Iq. A spectroscopic temperature can be evaluated within error limits of less than ± 1%.
Studies of the Energetics and Structures of Clusters of Molecules about Ions Utilizing High Pressure Mass Spectrometer and Laser Photodissociation Techniques
Authors: Castleman A. W. , Holland P. M. , Hunton D. E. , Keesee R. G. , Lindeman T. G. , Peterson K. I. , Schelling F. J. , Upschulte B. L. 
Published: July 2012

AbstractThe results of studies of ion cluster bonding contribute knowledge of the interaction potential between ions and molecules, as well as an understanding of the microscopic details of solvation, surface and nucleation phenomena. For a number of years we have employed a high pressure mass spectrometric technique to measure the bond energies for the successive attachment of several classes of polar molecules to a variety of anions and cations. A comparison of data for ions of both open and closed electronic structure shows a strong disposition for partial co‐valent bonding with ligands of various classes. The importance of the dipole moment and the polarizability of the ligands in governing their bonding to ions is discussed. — Laser‐induced photodissociation studies are of value in determining the structure and photostability of ion clusters as well as in probing the changing properties of negative ions as a function of the degree of clustering with ligands. Experiments were undertaken in our laboratory to elucidate the mechanisms of photodissociation of CO3− co‐clustered with water. Photodissociation cross sections and reaction channels in the energy range 1.9 to 2.2 eV are discussed.
On the Concentration Dependence of the Mean Aggregation Number of Ionic Micelles as Determined by Stopped‐Flow Experiments
Authors: Baumgardt K. , Klar G. , Strey R. 
Published: July 2012

AbstractThe analysis of the amplitudes in T‐jump experiments on aqueous micellar solutions yields the dependence of the critical micelle concentration and the mean aggregation number m of the micelles on temperature, whereas p‐jump experiments yield the corresponding dependence on pressure. In this paper we have, accordingly, evaluated the dependence of m on the total detergent concentration from stopped‐flow amplitudes (i.e. from concentration‐jump experiments). The experiments were performed on H2O‐NaDS and H2O‐NaDS. It turned out that the mean aggregation number of these detergents appears to increase with increasing detergent concentration, in accord with the results of other authors who have found an increase of m with increasing concentration of an added electrolyte.
Vorspiel Ohne Finale (?)
Authors: Steiner Josef 
Published: August 2012

AbstractSeit mehr als einem Jahrzehnt wird auf nationaler und europäischer Ebene intensiv über die Notwendigkeit des Abbaus von bürokratischen Regelungen diskutiert. Allgemein besteht aber dennoch der Eindruck, dass vorwiegend aus Brüssel immer neue Verordnungen über die EG‐Mitgliedsländer hereinbrechen und dort – oft mit viel Mühe und Aufwand – in nationales Recht umgesetzt werden (müssen). Aus diesem Regelungsdickicht sind für den Bereich des Bauens vor allem zu nennen:– Die Qualitätsmanagementregeln nach ISO 9000– Die Dienstleistungsrichtlinie– Das Antidiskriminierungsgesetz– Das Gesetz über Wettbewerbsbeschränkung– Die aufwendige Harmonisierung der Europäischen technischen Baubestimmungen– Die europäische Richtlinie über die Verfahren zur Vergabe öffentlicher Bauaufträge, Lieferaufträge und Dienstleistungsaufträge (VOF)Diese und weitere Gesetze und Verordnungen haben vor allem für Architekten und Bauingenieure den Aufwand für die Projektbeschaffung und für die Projektbearbeitung erheblich vergrößert.Prelude without Final. Experience with the Regulations of Contract Awards for Independent Professional Services – VOF –The need to reduce the bureaucratic regulations at the national and European level has been discussed thoroughly for over a decade. Even so, there is the general impression that new directives are being foisted on EU member states from Brussels where they (must then) be implemented in national legislation, frequently with considerable difficulty and expense. From amongst the jungle of regulations where the civil engineering sector is concerned, those requiring special mention are:– The quality management regulations according to ISO 9000– The services directive– The antidiscrimination law– The law on the restriction of competition– The complicated harmonization of European technical building regulations– The European directive concerning the procedures for the award of public works contracts, public supply contracts and public service contracts (VOF)For architects and civil engineers in particular, these and other laws and directives have considerably increased the project procurement and project handling costs.
Bioreactor environment‐sensitive sentinel genes as novel metrics for cell culture scale‐down comparability
Authors: Kondragunta Bhargavi , Joshi Bharat H. , Han Jing , Brorson Kurt A. , Puri Raj K. , Moreira Antonio R. , Rao Govind 
Published: July 2012

AbstractScale‐down of bioreactors is currently done based on matching one or more measurable parameters such as kLa and P/V, which could result in insufficient process comparability. Currently, there is a lack of genomic translational studies in cell culture scale‐down, which could help delineate measurable cellular attributes for improved scale‐down. In this study, we scaled‐down from a typical bench‐scale 5‐L bioreactor to a novel high‐throughput 35‐mL minibioreactor based on matching oxygen transfer rate, which resulted in cell growth and product‐related discrepancies using Sp2/0 cells. Performing DNA microarrays on time‐course samples from both systems, we identified ∼200 differentially expressed transcripts, presumably because of bioreactor aeration and mixing differences with scale‐down. Evaluating these transcripts for bioreactor‐relevant cellular functions such as oxidative stress response and DNA damage response, we chose 18 sentinel genes based on their degree of difference and functionality, which we further verified by quantitative real‐time polymerase chain reaction (qRT‐PCR). Tracking the differential expression of Sod1, Apex1, and Odc1 genes, we were able to correlate sparging‐related damage and poor mixing, as possible causes for physiological changes such as prolonged culture in minibioreactors. Additionally, to verify our sentinel gene findings, we performed follow‐up improved scale‐down studies based on gene analysis and measured transcriptomic changes. As a result, qRT‐PCR‐based genomic profiles and cell growth profiles showed better convergence between the improved minibioreactor conditions and the model 5‐L bioreactor. Our results broadly show that based on the knowledge from transcriptomic changes of sentinel gene profiles, it is possible to improve bioreactor scale‐down for more comparable processes. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Usefulness of transesophageal echocardiography during implantation of the CoreValve percutaneous aortic prosthesis: Influence of the learning curve
Authors: del Campo Laura Cejudo Díaz , Rubio Dolores Mesa , Ortiz Martin Ruiz , Ortega Mónica Delgado , Pan Manuel , Pineda Soledad Ojeda , Fernandez Elena Villanueva , Aguilera Jose Lopez , de Lezo Jose Suarez 
Published: August 2012

AbstractBackground and Objectives: The purpose of this study was to evaluate the usefulness of transesophageal echocardiography during the implantation of the CoreValve percutaneous aortic prosthesis and the influence of the learning curve in its indications. Methods: From April 2008 to January 2010, 53 patients were treated for symptomatic severe aortic stenosis with a CoreValve percutaneous aortic prosthesis. Transesophageal echocardiography was performed during the procedure for two reasons: if a discrepancy between the measures of the aortic annulus arose before the implantation and to provide visualization if a complication occurred during the procedure. Patients were divided in to two groups based on the learning curve (group I:the first 25 patients, group II: all of the subsequent patients). Results: Thirty‐six transesophageal echocardiographies were performed on 28 patients (53%).In 15 cases the indication was to assist us in determining the proper sized prosthesis, and in the other 21 cases it was performed due to a complication during the procedure. The numbers of intraprocedure transesophageal echocardiographies were similar in both learning‐curve groups, (64% in group I vs. 71% in group II, P = 0.56) but the proportion of the studies indicated by serious complications was significantly lower in the second period of the learning curve (67% in group I vs. 17% in group II, P < 0.05). Conclusions: In our experience, transesophageal echocardiography was very useful in more than one‐half of the patients during the implantation of the CoreValve percutaneous aortic prosthesis. After overcoming the learning curve, its indication due to serious procedure‐related complications decreased significantly. © 2012 Wiley Periodicals, Inc.
A study on using uncertain time series matching algorithms for MapReduce applications
Authors: Rizvandi Nikzad Babaii , Taheri Javid , Moraveji Reza , Zomaya Albert Y. 
Published: August 2012

SUMMARYIn this paper, we study CPU utilization time patterns of several MapReduce applications. After extracting running patterns of several applications, the patterns along with their statistical information are saved in a reference database to be later used to tweak system parameters to efficiently execute future unknown applications. To achieve this goal, CPU utilization patterns of new applications along with its statistical information are compared with the already known ones in the reference database to find/predict their most probable execution patterns. Because of different pattern lengths, dynamic time warping (DTW) is utilized for such comparison; a statistical analysis is then applied to DTWs' outcomes to select the most suitable candidates. Furthermore, under a hypothesis, we also proposed another algorithm to classify applications under similar CPU utilization patterns. Finally, dependency between minimum distance/maximum similarity of applications and scalability (in both input size and number of virtual nodes) is studied. Here, we used widely used applications (WordCount, Distributed Grep, and Terasort) as well as an Exim MainLog parsing application to evaluate our hypothesis in automatic tweaking MapReduce configuration parameters in executing similar applications scalable on both size of input data and number of virtual nodes. Results are very promising and showed the effectiveness of our approach on a private cloud with up to 25 virtual nodes. Concurrency and Computation: Practice and Experience, 2012. Copyright © 2012 John Wiley & Sons, Ltd.
Frequency–amplitude relations for cross‐coupled voltage‐controlled oscillator
Authors: Eskandarian Abdollah 
Published: July 2012

ABSTRACTDependence of frequency on amplitude and control bias is considered for the cross‐coupled voltage‐controlled oscillator. Closed form expressions are derived for frequency of oscillation as a function of amplitude, for positive and negative control bias voltages. Theory of nonlinear ordinary differential equations is utilized to show that the capacitance–voltage relation is the main cause of frequency shift with amplitude. Furthermore, the case of small amplitudes relative to control voltage is analyzed, and a closed form expression is derived for dependence of frequency on amplitude. This relation is then verified using the concept of effective capacitance. The effective capacitance approach is also used to extend the analysis to large voltage swings. Dependence of frequency on tuner control voltage is calculated for both bias polarities. Implications of the aforementioned equations for voltage‐controlled oscillator performance are discussed. Numerical calculations and simulations are used to compare and verify the closed form equations, showing good agreement. Copyright © 2012 John Wiley & Sons, Ltd.
Towards a Deep Desilication/Dealumination of NU‐10 Zeolite: Shape‐Selectivity Regulation
Authors: Sá Couto Clara , Matias Patrícia , Santos Edgar T. , Fernandes Auguste , Graça Inês , Lopes José M. , Ribeiro Maria F. 
Published: July 2012

AbstractThe present work was aimed at performing alkaline desilication of different severities, in order to generate a broad range of mesopore volumes within the framework of the intermediate pore size NU‐10 zeolite and to evaluate both physicochemical and catalytic consequences. The shape‐selective sensitive o‐xylene isomerisation reaction was used as a characterisation method of zeolite pore modification. Thus, several NU‐10 samples, with preserved crystallinity, were obtained by treatment of a microporous parent NU‐10 sample with sodium hydroxide solutions of different concentrations (0.4–0.6 M), at several contact times (15, 30, 45, 60 and 120 min) and at 353 K. The characterisation by nitrogen adsorption allowed the evaluation of the micropore volumes of the samples and the mesopore volumes generated by desilication, as well as the external surface area. Toluene adsorption experiments were also performed, an important increase in the toluene adsorption capacity for increasing desilication levels being observed, except for the most severely modified samples. The sample treated at 0.6 M for 60 min revealed lower toluene retention, probably due to a higher level of extra‐framework aluminium and silicon species remaining in the internal porosity. In the case of aluminium species, they were detected by 27Al NMR spectroscopy, which is also in agreement with the pronounced increase in the number of Lewis acid sites detected for the most severely treated samples. A slight decrease in the initial o‐xylene isomerisation activity, at 673 K, was generally noticed as a consequence of desilication, and this can be related to a slight decrease in the concentration of protonated sites. Nevertheless, for intermediate‐severity‐treated samples, the activity per acid site increased significantly when compared with the parent zeolite, suggesting easier reactant accessibility. Furthermore, the para/meta‐xylene product molar ratio decreased and, therefore, the zeolite shape selectivity, thus reinforcing the hypothesis of an extra space generation consequence on the catalytic properties.
Naphthyl Derivatives Functionalised with Electron Acceptor Units – Synthesis, Electronic Characterisation and DFT Calculations
Authors: Planells Miquel , Robertson Neil 
Published: July 2012

AbstractA series of unsymmetrical dyes containing a naphthyl unit connected to an electron acceptor moiety was designed and synthesised. By modifying the electron acceptor unit, a shift of the LUMO energy level as well as its distribution through the molecule were achieved. These dyes were fully characterised by optical, computational and electrochemical techniques. In addition, crystal structures reveal different packing depending upon the nature of the acceptor. Their potential use as electron acceptor materials for organic photovoltaics (OPVs) was also investigated by photoluminescence studies of blends with the common OPV polymers P3HT and PCDTBT.
Experimental investigation on dynamic and quasi‐static behavior of low‐rise reinforced concrete walls
Authors: Carrillo Julian , Alcocer Sergio M. 
Published: July 2012

SUMMARYExperimental evidence supporting the fact that results from quasi‐static (QS) test of low‐rise reinforced concrete walls may be safely assumed as a lower limit of strength and displacement, and energy dissipation capacities are still scarce. The aim of this paper is to compare the seismic performance of 12 reinforced concrete walls for low‐rise housing: six prototype walls tested under QS‐cyclic loading and six models tested under shaking table excitations. Variables studied were wall geometry, type of concrete, web steel ratio, type of web reinforcement and testing method. Comparison of results from dynamic and QS‐cyclic tests indicated that stiffness and strength properties were dependent on the loading rate, the strength mechanisms associated with the failure mode, the low‐cycle fatigue, and the cumulative parameters, such as displacement demand and energy dissipated. Copyright © 2012 John Wiley & Sons, Ltd.