bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical behavior of some copper alloys in sulfuric acid solutions
Authors: El‐Feky H. E. , Helal N. H. , Negem M. R. 
Published: October 2009

AbstractIn this article, the corrosion behavior of CuFe and CuAlFe was studied in H2SO4 solutions in the absence and presence of different concentrations of some inorganic additives, Na2MoO4, K2Cr2O7, KIO3, and Na2B4O7. The techniques of measurements used were open‐circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The polarization measurements indicated that the corrosion current, Icorr, of CuFe is less than that of CuAlFe. The investigated additives in H2SO4 shifted Ecorr to more positive values and increases Icorr. Impedance measurements indicated that Nyquist plots for CuFe may be regarded as a semi‐circle in early stages of immersion and tends to be a part of semi‐circle with elapse of time and a well‐defined inductive loop appears. In case of CuAlFe, the Nyquist plots tends to be semi‐circle or depressed semi‐circle. The values of Rp for CuFe are higher than those for CuAlFe. On the other hand, the values of Cdl for CuFe are lower than those obtained for CuAlFe. The presence of these additives in H2SO4 solutions decreases the values of polarization resistance (Rp) and increases the values of corrosion current density (Icorr) and capacitance of double layer (Cdl).
Experimental evaluation of high solid polyurethane coating in the presence of salt at high temperature
Authors: Rezaei F. , Sharif F. , Sarabi A. A. , Kasiriha S. M. , Rahmanian M. , Akbarinezhad E. 
Published: October 2009

AbstractIons' presence and high temperature affect the performance and service life of all types of coatings including pipeline coatings. Pipeline coatings are relatively thick and their evaluations are very time consuming. In this study, experiments on the thick coating samples (roughly 250 and 400 µm) of high solid polyurethane (HSPU) have been conducted to evaluate the effect of high temperature and presence of ions in the media, on the performance of coatings. The experiments were performed in two types of electrolytes, sodium chloride solution (3.5 wt% fraction) and distilled water, at two temperature levels of 25 and 75 °C, respectively. The coating performance was studied using electrochemical spectroscopy impedance (EIS) method. The results of experiments show that the presence of ions reduces the service life of the coating and higher temperature accelerates the degradation process further if oxygen is not limited.
Electrochemical study of stainless steels used in an oil company by electrochemical impedance
Authors: Boudinar Y. , Innal F. , Chadli H. , Belmokre K. 
Published: October 2009

AbstractLocalized corrosion is a serious problem for stainless steel exposed in a chloride solution. In this context, the present work concerns the study of electrochemical behavior of 316 (A and B) and 430 (C and D) stainless steels, where A and C are laboratory steels, while steels B and D were taken from heat exchangers tubes (after 10 years of operation). This study has addressed three different aqueous environments: (1) monoethanolamine (MEA) 15%, (2) natural seawater (NSW), and (3) NaCl 3%, using the technique of potentiodynamic polarization curve complemented by electrochemical impedance spectroscopy (EIS). The obtained experimental electrochemical parameters (Ecorr, Jcorr, Er, Cd, Rtc, and constant phase element) were used to compare the corrosion resistance of the tested steels. As a result, the nobility of these steels in NaCl 3% and in MEA 15% solutions is established in the following order: 316 (A) > 316 (B) > 430 (C) > 430 (D), where Er moves increasingly toward the positive direction, indicating a good protection against corrosion. In addition, the results show that the effect of the electrolyte (aggression) is characterized by increased corrosion potential and a decrease in the passivity domain for all samples. The hierarchy of the nobility of steels A and C in these electrolytes can be determined as follows: MEA 15% > NSW > NaCl 3%.
Electrochemical corrosion behaviour of a Ti‐IF steel and a SAE 1020 steel in a 0.5 M NaCl solution
Authors: Osório W. R. , Peixoto L. C. , Garcia A. 
Published: October 2009

AbstractInvestigations concerning the electrochemical corrosion behaviour of low carbon (LC) and ultra‐low carbon (ULC) steels are relatively scarce and limited. The present study aims to compare electrochemical impedance parameters and potentiodynamic polarization curves of an LC steel and an ULC Ti‐interstitial free (IF) steel evidencing the effects of carbon content and pearlite fraction on the electrochemical corrosion behaviour. Corrosion tests were carried out in a 0.5 M NaCl solution at 25 °C with a pH range between 6.5 and 6.8. It was found that the IF steel sample presents an electrochemical corrosion resistance, which is slightly higher than that of the LC steel sample.
Strength of spot‐welded steel sheets in corrosive environment
Authors: Mukhopadhyay G. , Bhattacharya S. , Ray K. K. 
Published: October 2009

AbstractThe load bearing capacity (LBC), often referred to as strength, of spot‐welded joints on as‐received and pre‐strained sheets of an interstitial free (IF) steel has been examined under 3.5% sodium chloride solution using tensile‐shear (TS) specimens. These tests have been carried out under three different test conditions: (i) after immersing the samples in the solution for various duration of time, (ii) at various slow strain rates by keeping the samples in solution, and (iii) at slow strain rate under in situ hydrogen charging. Analyses of the results infer that (i) increased duration of immersion of the samples in aggressive environment decreases their LBC but increases their extension corresponding to the maximum load (EML), (ii) slow strain rate tests in the solution indicate marginal decrease of LBC and EML of the spot‐welds, (iii) the LBC and EML of the spot‐welds of pre‐strained sheets decrease considerably with cathodic hydrogen charging while EML of the spot‐welded joints on the as‐received sheets is found to improve, and finally, (iv) the detrimental effect of corrosive environment increases with increased pre‐strain of the investigated sheets. These observations have been discussed together with post‐failure examinations of the broken fractured surfaces, which have assisted in understanding their failure mechanism.
Hollow fibre‐supported liquid membrane extraction and LC‐MS/MS detection for the analysis of heterocyclic amines in urine samples
Authors: Busquets Rosa , Jönsson Jan Åke , Frandsen Henrik , Puignou Lluís , Galceran Maria Teresa , Skog Kerstin 
Published: October 2009

AbstractHeterocyclic amines (HCAs) are potent mutagens/carcinogens to which humans are frequently exposed through the consumption of cooked meat and fish food. The effect of normal intake of HCAs and their role in the aetiology of human cancer is unknown. To some extent, limitations of the existing analytical methods in monitoring the low levels of HCAs in biological samples have hindered obtaining conclusive results. In this study, a method for the analysis of HCAs in human urine has been studied to detect HCAs and metabolites at levels resulting from consumption of food cooked at ordinary conditions. The analytical method consisted of extraction and clean‐up by the novel technique liquid‐phase microextraction combined with LC‐MS/MS. The effect of pH during the extraction and hydrolysis step was examined. High sensitivity was achieved when the extraction was performed in raw urine adjusted to pH 5.5, 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine being detected from 2 pg/g urine, levels comparable with a normal exposure. Good reproducibility and repeatability was obtained for 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine and 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline, below 9% using isotopic dilution. The performance of the method on 9H‐pyrido[3,4‐b]indole, 2‐amino‐1‐methyl‐6‐(4′‐hydroxyphenyl)imidazo[4,5‐b]pyridine and 2‐amino‐1‐methyl‐6‐(5‐hydroxy)phenylimidazo[4,5‐b]pyridine was also studied.
Traffic flow continuum modeling by hypersingular boundary integral equations
Authors: Romero Luis M. , Benitez Francisco G. 
Published: October 2009

AbstractThe quantity of data necessary in order to study traffic in dense urban areas through a traffic network, and the large volume of information that is provided as a result, causes managerial difficulties for the said model. A study of this kind is expensive and complex, with many sources of error connected to each step carried out. A simplification like the continuous medium is a reasonable approximation and, for certain dimensions of the actual problem, may be an alternative to be kept in mind. The hypotheses of the continuous model introduce errors comparable to those associated with geometric inaccuracies in the transport network, with the grouping of hundreds of streets in one same type of link and therefore having the same functional characteristics, with the centralization of all journey departure points and destinations in discrete centroids and with the uncertainty produced by a huge origin/destination matrix that is quickly phased out, etc. In the course of this work, a new model for characterizing traffic in dense network cities as a continuous medium, the diffusion–advection model, is put forward. The model is approached by means of the boundary element method, which has the fundamental characteristic of only requiring the contour of the problem to be discretized, thereby reducing the complexity and need for information into one order versus other more widespread methods, such as finite differences and the finite element method. On the other hand, the boundary elements method tends to give a more complex mathematical formulation. In order to validate the proposed technique, three examples in their fullest form are resolved with a known analytic solution. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of metal oxides on intumescent flame‐retardant polypropylene
Authors: Wu Na , Yang Rongjie 
Published: October 2009

AbstractVariable amounts of transition metal oxides (MO), such as MnO2, ZnO, Ni2O3, etc., were incorporated into blends of polypropylene (PP)/ammonium polyphosphate (APP)/dipentaerythritol (DPER) with the aim of studying and comparing their effects with main‐group MO on intumescent flame retardance (IFR). The PP/IFR/MO composites were prepared using a twin‐screw extruder, and the IFR behavior was evaluated through oxygen index and vertical burning tests. The progressive enhancement of flame retardancy has proved to be strongly associated with the interaction between APP and MO. With the aid of thermogravimetry (TG) analysis, Fourier transform infrared (FTIR) spectra and scanning electron microscopy, Ni2O3 has been shown to be the most effective among the aforementioned three MO. The flame‐retardant mechanism of the IFR system is also discussed in terms of catalytic charring, which relates to complex formation through the d‐orbitals of the transition metal elements. It is considered that the melt viscosity of a PP/APP/DPER blend containing Ni2O3 corresponds well to the gas release with increasing temperature. Copyright © 2009 John Wiley & Sons, Ltd.
Combining selected reaction monitoring with discovery proteomics in limited biological samples
Authors: Gupta Mukesh Kumar , Jung Jin Woo , Uhm Sang Jun , Lee Hookeun , Lee Hoon Taek , Kim Kwang Pyo 
Published: October 2009

AbstractSimultaneous quantification of multiple proteins by selected reaction monitoring (SRM) has several applications in cell signaling studies including embryo proteomics. However, concerns have recently been raised over the specificity of SRM assays due to possible ion redundancy and/or sequence similarity of selected peptide with multiple non‐related proteins. In this Viewpoint article, we discuss some simple measures that can increase our confidence in the accuracy of SRM scans used in proteomic experiments. At least in embryonic samples from porcine species, these measures were found to be useful in validating MS‐identified differentially expressed proteins. Among the nine proteins analyzed by SRM assay, all the proteins that were found to be up‐ or down‐regulated in MS experiment were also faithfully up‐ or down‐regulated in SRM assay.
Synthesis and self‐assembly behavior of amphiphilic polypeptide‐based brush‐coil block copolymers
Authors: Cai Chunhua , Zhu Wenjie , Chen Tao , Lin Jiaping , Tian Xiaohui 
Published: October 2009

AbstractSynthesis and self‐assembly behavior of a novel amphiphilic brush‐coil block copolymer bearing hydrophilic poly(ethylene glycol) segment and hydrophobic polypeptide brush segment were presented in this work. The poly(γ‐benzyl‐L‐glutamate) (PBLG) brush is synthesized through “grafting from” strategy by ring‐opening polymerization of γ‐benzyl‐L‐glutamate‐N‐carboxyanhydride (BLG‐NCA) initiated by the flanking terminal primary amino group of macroinitiator. The copolymers were characterized by 1H NMR, gel permeation chromatography, Fourier transform infrared, circular dichroism spectrum, and differential scanning calorimetry. The self‐assembly behavior of the brush‐coil block copolymers in aqueous solution was investigated by means of transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and laser light scattering. Spherical micelles were observed when the length of PBLG brush is shorter. The aggregate morphology transforms to spindle‐like micelles and then to rod‐like micelles, as the length of polypeptide brush increases. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5967–5978, 2009
DNA binding to electropolymerized N‐substituted polypyrrole surfaces
Authors: Percec Simona , Skidd Gabriel , Zheng Ming 
Published: October 2009

AbstractThis study explores the use of N‐substituted polypyrroles as a route for localizing DNA molecules onto conducting surfaces. N‐substituted pyrrole monomers containing N‐hydroxysuccinimidyl groups for DNA binding reactions were synthesized. These monomers were electro‐copolymerized under different conditions on platinum or gold working electrodes in a three‐electrode/single compartment cell. Subsequent DNA reactions were performed by incubating the resulting polymer conductive films with amino‐substituted DNA sequences. In addition, the electro‐copolymerization reactions of pyrrole monomers were conducted on preselected electrode positions of the Molecular Nanosystems (MNS) wafers and the formation of conductive films was demonstrated. In these experiments, it was determined also that by controlling the electro‐copolymerization reactions, the conductive films can be restricted to grow on specific locations of the MNS wafer. This was achieved by electrically passivating the chosen electrodes with self‐assembled multilayers (SAM)s of alkane thiols. Hexadecane thiol (HDT) was found the most efficient in forming SAMs and in preventing the pyrrole electropolymerization. Various analytical techniques including AFM, IR, and cyclic voltammetry (CV) were used to characterize the monomers, the electropolymerized polymers, and the attachment of amine‐terminated DNA to polypyrrole copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6014–6024, 2009
Anhydrous state proton conduction in sulfonated bisphenol a polyetherimide with 1H‐1,2,4 triazole as proton solvent
Authors: Guhathakurta Soma , Min Kyonsuku 
Published: October 2009

AbstractIn this study, bisphenol A polyetherimide was sulfonated to various degrees (22, 48, and 62%) by trimethylsilylchlorosulfonate (TMSCS). Novel anhydrous proton conducting polyelectrolytes were prepared by the incorporation of 1H‐1,2,4‐triazole (Taz) as proton solvent in sulfonated polyetherimide (SPEI) matrix. The conductivity reached about 2 × 10–3 S/cm at 80 °C and 10–2 S/cm at 140 °C. The temperature dependence proton conductivity of the polyelectrolytes followed Arrhenius equation. The conductivity improved considerably at a temperature close to the triazole melting temperature in SPEI(X)H matrix. It was proposed that the high mobility of the triazolium ions (vehicle diffusion), in addition to structure diffusion, contribute to the high conductivity of these proton conducting electrolytes above the melting temperature of triazole. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2178–2187, 2009
Stable colloidal Co–Pd nanocatalysts for carbon nanotube growth
Authors: Berenguer A. , Cantoro M. , Golovko V. B. , Hofmann S. , Wirth C. T. , Johnson B. F. G. , Robertson John 
Published: October 2009

AbstractThe standard preparation method for catalysts for surface‐bound growth of carbon nanotubes (CNT) is to sputter or evaporate the metal catalyst (Fe, Co, and Ni) onto the surface. A lower cost method for large areas is to use liquid delivery. Colloids have the advantage of containing the catalyst in nanocluster form. Our previously developed colloidal catalysts were successful for growth but had limited shelf‐life due to oxidation and coagulation. Here, we develop an air‐stable colloidal catalyst with long shelf‐life of many months to years.
Oxide catalysts for carbon nanotube and few layer graphene formation
Authors: Rümmeli Mark H. , Schäffel Franziska , Bachmatiuk Alicja , Trotter Geoff , Adebimpe David , Simha‐Martynková Grazyna , Plachá Daniela , Rellinghaus Bernd , McCormick Paul G. , Borowiak‐Palen Ewa , Ayala P. , Pichler Thomas , Klingeler Rüdiger , Knupfer Martin , Büchner Bernd 
Published: October 2009

AbstractOxides are rapidly emerging as an exciting alternative to metal catalysts for carbon nanotubes (CNT) formation because they are more easily integrated in Si technology, are usually easily removed in purification steps and are cheap. In this contribution we highlight the potential of oxides to synthesise single walled carbon nanotubes (SWCNT) (via laser evaporation), multiwalled carbon nanotubes and few layer graphene (via thermal CVD).magnified imageSchematic illustration of graphitic carbon grown from oxide step site to form a CNT (left image) or graphene layer (right image).
Taylor–Proudman columns in non‐hydrostatic divergent baroclinic and barotropic flows
Authors: de la Torre Juárez Manuel 
Published: October 2009

AbstractThe Taylor–Proudman theorem states that the velocity of slow, steady flow in a rotating incompressible fluid does not change along the direction of the rotation axis. This fundamental result has been invoked to explain blocking phenomena observed over topographic features in oceanic and atmospheric flows on Earth and atmospheric patterns observed in giant gas planets even in cases where the assumption of incompressibility fails. The possible existence of Taylor–Proudman columns is analyzed here for a less restrictive family of non‐hydrostatic divergent density‐stratified flows, including situations where the stratification gradient and rotation axis are not parallel. The results show that Taylor–Proudman‐like constraints are possible in baroclinic inviscid and viscous nonlinear flows of constant vorticity, Beltrami flows and low‐Rossby‐number flows. It is found that (1) the baroclinic term is moderated by a factor of the order of the Rossby number, (2) a conservation law can be found for baroclinic flows and (3) Taylor–Proudman columns will be eroded in viscous flows. One particular result stressed in this note is its interpretation in equatorial regions, where the rotation axis is perpendicular to the main stratification gradient, and it is argued that Taylor–Proudman columns could be difficult to discern with observational parameters from convective cells with only zonal and vertical transport. Copyright © 2009 Royal Meteorological Society
Characterization of the impact of geostationary clear‐sky radiances on wind analyses in a 4D‐Var context
Authors: Peubey C. , McNally A.P. 
Published: October 2009

AbstractThe impact of geostationary clear‐sky radiances (CSRs) on 4D‐Var wind analyses has been investigated by running a set of observing system experiments. Analysis scores have been calculated to measure the ability of individual satellite datasets to improve the wind analysis, starting from a no‐satellite baseline. In this context, the assimilation of CSRs from the two water‐vapour channels on Meteosat‐9 has been found to improve the wind analysis throughout the troposphere, with the strongest signal at 300 and 500 hPa. Indeed, for the Northern Hemisphere and the Tropics, the CSR impact at these levels exceeds that of the Meteosat‐9 atmospheric motion vectors (AMVs), the sampling of the latter in the assimilation being rather limited. Conversely, the impact of AMVs exceeds that of CSRs in the lower troposphere, where the latter provide very little direct information. This demonstrates the complementarity of the two datasets in the operational 4D‐Var wind analysis. The mechanisms through which the assimilation of CSRs can impact wind analyses have been isolated. The dominant effect is that of humidity‐tracer advection, by which the wind field is adjusted in order to fit observed humidity features via the minimization of the 4D‐Var cost function. Other mechanisms, such as balance constraints and the cycling of the forecast model that links the humidity and wind variables, have been found to play a minor role. The benefit of having frequent CSR images within the assimilation window has also been demonstrated. Copyright © 2009 Royal Meteorological Society
Balanced and unbalanced aspects of tropical cyclone intensification
Authors: Bui Hai Hoang , Smith Roger K. , Montgomery Michael T. , Peng Jiayi 
Published: October 2009

AbstractWe investigate the extent to which the azimuthally–averaged fields from a three‐dimensional, non‐hydrostatic, tropical cyclone model can be captured by axisymmetric balance theory. The secondary (overturning) circulation and balanced tendency for the primary circulation are obtained by solving a general form of the Sawyer–Eliassen equation with the diabatic heating, eddy heat fluxes and tangential momentum sources (eddy momentum fluxes, boundary‐layer friction and subgrid‐scale diffusion) diagnosed from the model. The occurrence of regions of weak symmetric instability at low levels and in the upper‐tropospheric outflow layer requires a regularization procedure so that the Sawyer–Eliassen equation remains elliptic. The balanced calculations presented capture a major fraction of the azimuthally–averaged secondary circulation of the three‐dimensional simulation except in the boundary layer, where the balanced assumption breaks down and where there is an inward agradient force. In particular, the balance theory is shown to significantly underestimate the low‐level radial inflow and therefore the maximum azimuthal‐mean tangential wind tendency. In the balance theory, the diabatic forcing associated with the eyewall convection accounts for a large fraction of the secondary circulation. The findings herein underscore both the utility of axisymmetric balance theory and also its limitations in describing the axisymmetric intensification physics of a tropical cyclone vortex. Copyright © 2009 Royal Meteorological Society