bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Hydrogen Storage in Graphene Oxide‐MWCNTs Composite at Room Temperature
Authors: Aboutalebi Seyed Hamed , Aminorroaya‐Yamini Sima , Nevirkovets Ivan , Konstantinov Konstantin , Liu Hua Kun 
Published: August 2012

AbstractHigh hydrogen capacity (up to 2.6 wt%) is reported for highly aligned structures of Graphene oxide‐Multiwalled carbon nanotubes composite at room temperature. It is demonstrated that the scalable liquid crystal route can be employed as a new method to prepare unique 3‐D framework of graphene oxide layers with proper interlayer spacing as building blocks for cost‐effective high‐capacity hydrogen storage media. The strong synergistic effect of the intercalation of MWCNTs as 1‐D spacers within graphene oxide frameworks resulted in unrivalled high hydrogen capacity at ambient temperature. The mechanisms involved in the intercalation procedure are fully discussed. The main concept behind intercalating one‐dimensional spacers in between giant GO sheets represents a versatile and highly scalable route to fabricate devices with superior hydrogen uptake.
Beyond Market Access: Value From Food Safety Certification of Fresh Strawberries
Authors: Woods Mollie , Thornsbury Suzanne , Raper Kellie Curry 
Published: July 2012

ABSTRACTNot all food safety practices are legislatively mandated; voluntary adoption is common but in many cases does not represent an exogenous choice for an individual firm that wants to maintain market access. The authors examine how adoption of food safety practices can also provide nonmarket‐access benefits to a firm. In contrast to previous work that focused on consumer demand impacts from adoption and/or third‐party certification, the authors concentrate on cost‐saving benefits and particularly on reduction in product shrinkage. They use an interregional model of the North American fresh strawberry market to illustrate whether firms are able to capture such savings in a competitive market, given market structure and regional trade patterns. © 2012 Wiley Periodicals, Inc.
Development of electromagnetic interference shielding materials from the composite of nanostructured polyaniline‐polyhydroxy iron‐clay and polycarbonate
Authors: Reena Viswan Lilly , Sudha Janardhanan Devaki , Ramakrishnan R. 
Published: July 2012

AbstractIn the present study, we demonstrate the development of novel electromagnetic interference shielding material from the composite of nanostructured polyaniline‐polyhydroxy iron‐clay and polycarbonate through solution blending process. Onset of percolation threshold has been manifested from the morphological studies in combination with electrical conductivity measurements. Temperature‐dependent electrical conduction mechanism was studied by applying Mott theory and was found to follow 3D variable range hopping (VRH) model. The presence of interaction between the host matrix and the nanofiller was studied by rheological property measurement in combination with Fourier transform infrared spectroscopy. Films were further characterized for electromagnetic interference (EMI) shielding efficiency and thermomechanical properties. Results suggest that these transparent composite films can be used for the fabrication of EMI shielding/electrostatic dissipation material for the encapsulation of electronic devices and as electrostatic material for high technological applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Temperature responsive hydrogel with reactive nanoparticles
Authors: Xiao Li , Isner Austin B. , Hilt J. Zach , Bhattacharyya Dibakar 
Published: August 2012

AbstractThe application of temperature responsive hydrogels with ion‐exchange domain for nanoscale catalytic reactions is an emerging and attractive area because of the combination of individual unique features: temperature responsive tunability by the polymer domain and the high catalytic reactivity of the nanomaterial. Here, we report the entrapment and/or direct synthesis of reactive Fe and Fe/Pd nanoparticles (about 40–70 nm) in a temperature responsive hydrogel network (N‐isopropylacrylamide (NIPAAm), and NIPAAm—PAA). These nanoparticles are stabilized in the hydrogel network and the dechlorination (using trichloroethylene, TCE, as a model compound) reactivity in water is enhanced and controllable in the temperature range of 30–34°C involving polymer domain transitions at lower critical solution temperature (LCST) from hydrophilic to collapsed hydrophobic state. Water fraction modulation of the network and the enhancement of pollutant partitioning by the thermally responsive polymers play an important role in the catalytic activity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Structure and thermal behavior of EPDM/POSS composite fibers prepared by electrospinning
Authors: Xue Meng , Zhang Xian , Ma Lei , Gu Zhen , Lin Yongxing , Bao Chao , Tian Xingyou 
Published: August 2012

AbstractPolyhedral oligomeric silsesquioxane (POSS)‐containing ethylene‐propylene‐diene monomer (EPDM) composite fibers have been prepared by electrospinning method, with an average diameter of micron grade and fibrous structural morphology. The results of transmission electron microscopy, Fourier transform infrared, and UV‐Vis spectra reveal that POSS moieties have been dispersed in polymer matrix homogeneously. A combination of thermogravimetric analysis and thermogravimetric‐differential scanning calorimetry (TG‐DSC) united analysis was used to investigate the thermal behavior of the resulting fibers at elevated temperatures. The results show that composites exhibited great increase of thermal decomposition temperature and large reduction of total heat release compared with pure EPDM. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation of novel hyperbranched flame‐retardant polymer and its application into natural rubber systems
Authors: Yi Zhao , Jincheng Wang 
Published: July 2012

AbstractFlame‐retardant hyperbranched pentaerythritol (FR‐HPER) was prepared by condensation polymerization between pentaerythritol (PER), the monomer, and phosphate acid we prepared. It was then characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and matrix‐assisted laser desorption ionization time of flight mass spectrometer (MALDI‐TOF‐MS). This FR‐HPER was used in the preparation of natural rubber (NR)/FR‐HPER composites. Different types of NR/FR‐HPER composites were prepared with different amounts of FR‐HPER, and compared with the composites directly incorporated with PER. Then, the tensile, wear resistant, thermal, and FR properties were researched and compared. Results showed that some mechanical and FR properties of NR/FR‐HPER composites showed obvious improvements compared with that of NR and NR/PER systems. Schemes of toughening, wear resistant, and FR mechanism were proposed. The hyperbranched polymer may reduce the amount and size of voids in NR matrix, and thus increase the tensile properties. Meanwhile, the synergistic effect between nitrogen in PER and phosphorus in phosphate acid can increase the amount of carbonaceous layers, and thus may inhibit the pyrolysis degree of NR matrix during burning. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Influence of the temperature and deformation‐dependent dielectric constant on the stability of dielectric elastomers
Authors: Sheng Junjie , Chen Hualing , Li Bo , Wang Yongquan 
Published: August 2012

AbstractThe performance of dielectric elastomers is affected by temperature and deformation, but very few models account for the effect of both factors. Recent experiments showed that the dielectric constant of the most widely used dielectric elastomer varies significantly with respect to temperature and deformation. We propose a model to study the influence of changes in dielectric constant on the electromechanical stability of dielectric elastomer. The model predicts the stability criteria with physical interpretation of its dependence on dielectric constant and electrostrictive coefficient. The numerical simulation indicates that the stress due to electrostriction relies on the temperature and deformation dependent dielectric constant and contributes to enhance the stability of the dielectric elastomer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Polymorphism, Adduct‐Formation, and Structure of Trichloroacetic Acid Pentachlorophenyl Ester. A Chlorine NQR and DSC Study
Authors: Hashimoto Masao , Yoshioka Yoshichika 
Published: July 2012

AbstractTrichloroacetic acid petachlorophenyl ester (TCA‐O‐PCP) was found to form a 2:i adduct with benzene. It showed an eight line 35Cl NQR spectrum in the range 77 ≦ T/K ≦ 312 (decomposition temperature of the adduct). TCA‐O‐PCP was proved to have three crystalline phases. Phase I is stable in the range 77 ≦ T/K ≦ 403 (melting point of phase I). It exhibited also an eight line 35Cl NQR spectrum. A metastable phase (phase III) was obtained by quenching the liquid TCA‐O‐PCP to 77 K and on heating it was transformed into another metastable phase (phase II) at ca. 310 K. The transition III ⇄ II was enantiotropic and of higher order. At T/K ≧ ca. 360 a gradual, monotropic transition of II → I was observed. A 35Cl NQR spectrum having poor signal to noise ratio was found for phase III. A pronounced rise of the NQR frequency due to steric effect was observed for phase I of TCA‐O‐PCP. Remarkable differences in the characteristics of the NQR spectrum of ‐CCl3 group were found between the spectrum of the adduct and that of phase I. Some conformational change of TCA‐O‐PCP molecule accompanied by the adduct formation is thought to be responsible for the differences in the NQR spectrum.
Photoelectron Emission from Rhodamine B Adsorbed on Various Substrates
Authors: Ernst Lajos 
Published: July 2012

AbstractThe quantum yield of photoelectrons, emitted from rhodamine B layers, which were adsorbed on cleaved faces of ionic crystals and on polished faces of amorphous quartz, has served to estimate the effective densities of occupied dye states in a small energy range below the vacuum level. For NaCl(100), RbCl(100), and calcite (1010) substrates the energy distributions of these states are very similar. If the substrate is amorphous quartz, the density of dye states in the investigated energy range is negligible in comparison to that on the ionic crystals. Assumptions are made concerning the possible origin of the relatively high density of dye states generated on ionic crystals.
The Preparation of Potassium‐Vanadium Bronze K0.23V2O5 Studied by Evolved Gas Analysis and Hot Stage Optical Microscopy
Authors: van den Berg J. , van Dillen A. J. , Geus J. W. , Stolk M. C. 
Published: July 2012

AbstractThe preparation of the potassium‐vanadium bronze β‐K0.23V2O5 from K2CO3 and V2O5 was studied by evolved gas analysis and hot stage optical microscopy. – In two ways, the obtained results agree with the literature, i.e. evolution of oxygen was observed during solidification of a melt of the reactants, and the rate of formation of K0.23V2O5 turned out to be small. In addition we proved a compound of formula yK2O · zV2O5 to be an intermediate in the formation of K0.23V2O5. The product was analysed by precision X‐ray powder diffraction, scanning electron microscopy, thermal analysis (TG, DTG, DTA) and electron spin resonance. Because the K0.23V2O5‐sample will be used in catalytic experiments, the specific surface area was also determined.
Competition between Photocorrosion and Photooxidation of Redox Systems at n‐Type Semiconductor Electrodes
Authors: Gerischer Heinz , Lübke Margot 
Published: July 2012

AbstractPhotocorrosion of the semiconductors MoSe2, WSe2 and GaP in contact with [Fe(CN)6]4− ‐solution has been investigated by following the change of the redox potential in a closed electrolysis cell filled with redox electrolyte. Comparison with the integrated photocurrent gives the fraction of corrosion. It was found that the fraction of corrosion at constant bias and constant [Fe(CN)6]4− concentration is independent on illumination intensity at MoSe2 and WSe2, but increases at GaP. It decreases with increasing concentration of [Fe(CN)6]4−. Two reaction sequences are derived which describe the influence of the light intensity and of the concentration of the redox species quantitatively.
Far Infrared Spectra of Strongly Polar Molecules in Solid Solution. III. Cyanoacetylene, Cyanogen Chloride, and Propionitrile
Authors: Knözinger Erich , Wittenbeck Rüdiger 
Published: July 2012

AbstractThe spectral range around and below 100 cm−1 yields information on the intermolecular motion of molecules. In solid rare gas matrices aprotic molecules such as cyanogen chloride and propionitrile behave similarly to acetonitrile, which has previously been studied. All of these compounds are trapped in the matrix both as monomers and as antiparallel dimers, each of which exhibits a characteristic absorption spectrum uniquely related to intermolecular motions. H‐bonding compounds such as cyanoacetylene or hydrogen cyanide may be present in a solid rare gas matrix in the form of at least three different species: (a) isolated monomer molecules, (b) linear dimers, and (c) chainlike multimers. Each of these three species provides a characteristic far IR absorption pattern, which is, again, uniquely related to intermolecular motions.
Calorimetric and Other Studies of Phase Transitions in Solids
Authors: Chihara H. 
Published: July 2012

AbstractPrecision calorimetry can provide detailed information about the phase transitions in solids which is utilized to give insight into the nature of transitions and to check the model theories for their validity. Examples of studies are reviewed in this vein on the soft librational mode transition in p‐chloranil, the orientational glass transition in carbon monoxide, and the order‐disorder transition in hydrogen halides.
On the Order‐Disorder Phase Transition of Anilinium Halides. VI. Phase Transition in 4‐RC6H4NHX⊖, and C6H5NR'HX⊖, X = Br,I. A 79,81 Br and 127I NQR Study
Authors: Krishnan V. G. , Weiss Alarich 
Published: July 2012

AbstractBy79.81Br and 127I NQR spectroscopy 4‐FC6H4NHX⊖, 4‐FC6H4NDX⊖, 4‐(H5C2)C6H4NH X⊖, C6H5N(CH3)H X⊖, C6H5N(C2H5)H X⊖, X = Br and I, respectively, were studied in the temperature range 77 ≤ T/K ≤ 400. All the para substituted compounds experience a phase transition of higher order (presumably second order), the nature of which is most likely a ferroelastic one as it is in C6H5NHX⊖, X = Br,I. The isotope exchange H → D lowers the transition temperatures of the parafluoroanilinium halides, the resonance frequencies, the nuclear quadrupole coupling constant of the iodide, but raises the asymmetry parameter of the latter compound. Substitution of a hydrogen atom at the ‐ NH2 group in aniline inhibits the phase transition in C6H5N(CH3)HI⊖ and C6H5N(C2H5)H X⊖, X = Br, I. However, a phase transition of first order was observed for C6H5N(CH3)HBr⊖ at 141.5 K.
The Viscosity and Diffusion Coefficient of Binary Mixtures of Nitrous Oxide with He, Ne and CO
Authors: Kestin J. , Wakeham W. A. 
Published: July 2012

AbstractThe paper reports absolute measurements of the low‐density viscosity of binary mixtures of nitrous oxide with helium, neon and carbon monoxide in the temperature range 25 to 200°C. The viscosity data, which have an accuracy of ± 0.3%, are employed to confirm that the three systems, involving a weakly polar component, may be incorporated into the correlation scheme of the KRW law of corresponding states. The scaling parameters σij and ϵij which secure the optimum representation of the data by means of the universal collision integral Ω22 are derived. The internally consistent binary diffusion coefficients, calculated from the mixture viscosity, may themselves be successfully represented with the aid of the universal collision integral Ω11.
Kinetics and Mechanism of Hydrogen Diffusion in Hydrides of Titanium, Zirconium and TiNi0.5
Authors: Brauer E. , Gruner R. , Rauch F. 
Published: July 2012

AbstractHydrides of titanium and zirconium formed during cathodic polarization in acid solutions were investigated by the15N nuclear reaction method. Hydrogen depth profiles obtained in this way give informations about the hydrogen concentration in the metal, allowing to determine diffusion coefficients and therefrom to study the absorption of hydrogen by the metal lattice and the kinetics of the hydride layer growth. The mechanism was studied using Ti single crystals. The hydrogen diffusion was found to depend on the crystal orientation.
The Approach to Stationary States of Autocatalytic Systems in the Continuous‐flow Stirred Tank Reactor
Authors: Gray P. , Scott S. K. 
Published: July 2012

AbstractThe relaxation times characterizing the growth or decay of small perturbations from a stationary‐state established under continuous‐flow, well‐stirred conditions are derived for the autocatalytic sequences A + n B → (n + 1) B, with n = 1 or 2. The results show how as the flow‐rate is varied, relaxation times may gradually become very long compared with the mean residence‐time of the system. This lengthening is accompanied by a change in the mathematical form, from an exponential to an inverse dependence on time. This is not, however, a critical phenomenon, nor are infinite values possible.
Self‐Diffusion in Water‐Alcohol Mixtures. Part I. Water‐Methanol Solution of NaI
Authors: Hawlicka E. 
Published: July 2012

AbstractThe self‐diffusion coefficients of components in methanol‐water‐NaI system at 298.2 K have been investigated using open‐end capillary method. The influence of NaI concentration on methanol and water self‐diffusion coefficients has been studied. The dependences of self‐diffusion coefficients of sodium and iodide ions on NaI concentration have been determined. In methanol‐water‐NaI system the methanol self‐diffusion coefficient is greater than in pure methanol‐water mixture. The water self‐diffusion coefficient in the presence of NaI does not exhibit the minimum and in methanol rich mixtures is equal to the self‐diffusion coefficient of sodium ion.
Chemical Exchange and Raman Line Broadening. The Rate of Protolysis of Nitric Acid
Authors: Strehlow H. , Wagner I. , Hildebrandt P. 
Published: July 2012

AbstractThe influence of chemical exchange on the line shape in Raman spectroscopy is investigated. A theory, covering also the „fast case”︁ is derived. The results are compared with the similar but not identical equations valid for the kinetic line broadening in NMR spectroscopy. — The Raman line broadening technique is applicable only to extremely fast reactions with life times of the involved species shorter than about 10−11 s. — A practical application is given for the protolysis of nitric acid and the formation kinetics of ion pairs of NaNO3 both in highly concentrated solution. The rate constants obtained are higher than the rate constants for diffusion controlled reactions as calculated with the Smoluchowski‐Debye theory [1]. An explanation is proposed. The pK of nitric acid is reevaluated to be (−0.9 ± 0.3).
Arrhenius Parameters for the Reactions of O Atoms with Some Alkynes in the Range 300–1300 K
Authors: Homann K. H. , Wellmann Ch. 
Published: July 2012

AbstractThe rates of the reactions of oxygen atoms with acetylene (1), propyne (2), 1–3‐butadiyne (3), 1‐buten‐3‐yne (4), and 1‐butyne (5) in a discharge flow system have been measured in the temperature range 300 <T< 1300 K. — The Arrhenius expressions for the respective bimolecular rate constants areThere is a correlation between the activation energies and the ionization potentials of the alkynes.
Group Additivity for the Band Strength of the CF‐Chromophore for IR‐Photochemistry
Authors: Quack M. , Thöne H. J. 
Published: July 2012

AbstractIntegrated band strengths for rovibrational absorption in the frequency range of the CF‐chromophore (800 to 1300 cm−1) have been obtained from vapour phase IR‐spectra of twelve fluoroalkanes containing one or more CF groups. It is found that the chromophore band strength is about 1.7 (pm)2 for each CF group with some minor variations due to neighbouring substituents at the CF carbon atom. These variations can be accounted for by a simple, empirical equation. The results are discussed in relation to the chromophore principle in IR‐photochemistry. The frequency distribution of the chromophore absorption for primary, secondary, and tertiary alkyl fluorides is considered. The primary CF‐chromophore (R ‐ CH2 ‐ F) is suggested to be a particularly useful general chromophore for CO2‐laser pumping. The foundations of the group additivity for chromophore band strengths and some further applications are discussed as well.
Concentrated Aqueous Sodium Chloride Solutions from 200 to 600°C and to 3000 bar. — Phase Equilibria and PVT‐Data
Authors: Gehrig M. , Lentz H. , Franck E. U. 
Published: July 2012

AbstractThe specific volume of aqueous sodium chloride solutions with 6, 10, and 20 weight percent salt was measured from 200°C to 600°C and from 100 bar to 3000 bar. The uncertainty of the data is below 0.5%. Data are given of temperature, pressure, volume and composition at 24 points on the two‐phase boundary surface. About 230 values for the one‐phase region are presented. The critical curve for the binary system runs from 374°C and 220 bar for pure water to 500°C and nearly 600 bar for a solution with 12% salt. The specific volume at this point is 2.0 cm3 g−1. At 600 °C, 3000 bar and 20% salt a volume of 1.163 cm3 g−1 was found. The apparatus and procedure, which uses an autoclave with variable volume and sapphire window is described.
Time Resolved Visible and UV Absorption Spectroscopy of Bromine Clusters in Argon Matrices
Authors: Raffel B. , Wolfrum J. 
Published: July 2012

AbstractMatrix deposition was observed by a laser interference technique at deposition rates of 0.1 – 0.2 mmol/h at T = 10 K up to a matrix thickness of 1.1 · 10−4 m. Absorption spectra of Br2/Ar matrices (1 : 1000 – 1 : 300) examined quantitatively at λ = 300 nm and 415 nm showed an increase of molar bromine absorptivity with increasing Br2‐concentration. The increase of absorptivity may be explained by formation of Br2‐dimers during matrix deposition. Br2/Ar matrices were exposed to laser pulses at λ = 490 nm and showed a transient increase of absorption in the near UV (λ < 370 nm), a spectral region mainly due to Br2‐dimers. This increase presumably depends on laser excitation of Br2‐molecules situated in dimers into the B3π(O) state followed by deactivation into the ground state X1Σ. At least three exponentials are necessary to fit the transient signals with the lifetimes t1 = 3.5 μsec, t2 = 64 μsec, t3 = in the order of some msec.
Second Derivative UV Spectroscopy Study of the Thermal and Photochemical Reaction of NO2with SO2and SO3
Authors: Penzhorn R.‐D. , Canosa C. E. 
Published: July 2012

AbstractThe rate constants for the thermal reaction of NO2with SO2(k9= (1.4 ± 0.1) · 10−5l/mol · s) and SO3(k10= 88 ± 8 l/mol · s) have been determined employing second derivative UV spectroscopy. This technique was shown to be adequate to solve the problem of light scattering by aerosols always present in these systems. NOHSO4and H2O were found to strongly catalyze the NO2– SO2reaction. – The quantum yields of O2production and NO2depletion as well as the NO yield from the photolysis of NO2in the presence of SO2and/or CO2were determined at 366 nm as a function of SO2and CO2partial pressure at room temperature. The results were satisfactorily correlated with a reaction mechanism. – The relevance of the above reactions in urban aerosol formation are briefly commented.