bluuebunny/crossref_metadata_2025_split huggingface dataset:
HIGHLY IMPERMEABLE NANOCOMPOSITES OF BROMINATED BUTYL RUBBER WITH MODIFIED MONTMORILLONITE CLAY
Authors: Kumar Arun , Modi Satyam , Panwar Artee , Schmidt Daniel , Barry Carol M. F. , Mead Joey L. 
Published: December 2014

ABSTRACT
Incorporation of nanoclays in vulcanized rubber can enhance the barrier and mechanical properties, with the aid of intercalation, exfoliation, or both. Achieving a high degree of dispersion such as intercalation and exfoliation is critical for obtaining optimal properties. In this work, a stepwise approach was developed to disperse the natural montmorillonite (MMT) clay modified with a quaternary ammonium salt in brominated butyl rubber (BIIR). The solvent intercalation method followed by mechanical shear was used to effectively intercalate/exfoliate the MMT bundles. Special consideration was given to effectively remove the solvent from the solvent intercalated master batch. The nanocomposites fabricated using this technique showed a high degree of intercalation and exfoliation along with improved barrier, dynamic mechanical, and mechanical properties. This improvement in properties offers an opportunity for this material to be used in high-end applications requiring improved mechanical as well as barrier properties; an example is a thinner tire inner liner with reduced hysteresis, lower running temperatures, and reduced fuel consumption.
Validación y verificación de métodos de ensayos. Un dilema en los laboratorios de ensayos y en las auditorías de la acreditación
Authors: Delgado Gustavo 
Published: December 2014

El presente artículo tiene como objetivo fundamental establecer en forma clara y sencilla la diferencia entre validación y verificación de un método de ensayo. Se presenta una breve discusión de la selección y validación de los métodos de ensayos establecidos en la norma ISO/IEC 17025:2005. Se describe el proceso de normalización de un método. Se describen brevemente los parámetros de la validación como indicadores característicos del desempeño del método, brindando algunas breves orientaciones para su aplicación. Se presentan algunos contenidos de métodos normalizados, indicando las especificaciones a partir de los datos de validación. Y por último se describe el proceso de verificación y su diferencia con la validación, haciendo énfasis en la confirmación de las especificaciones del método. DOI: http://dx.doi.org/10.5377/universitas.v3i2.1661
Evaluación de la Incertidumbre en la Determinación de Plomo en Sangre por Voltamperometría de Redisolución Anódica, Aplicando el Modelo de Calibración Ponderado de Adición Patrón Generado por Simulación de Monte Carlo
Authors: Delgado Gustavo , Vanegas Manuel , Salazar Jairo 
Published: December 2014

El presente trabajo pretende demostrar que la evaluación de la incertidumbre en la determinación de plomo en sangre por voltamperometría de redisolución anódica, aplicando el análisis de regresión lineal ponderado por adición patrón y generado por simulación de Monte Carlo, tiene mayor congruencia con los resultados experimentales que con los obtenidos por la aplicación del enfoque clásico basado en la ley de la propagación de la incertidumbre. Para el primer caso, se elaboró el programa en Maple 13, basado en el algoritmo obtenido del suplemento 1 de la guía GUM 2008, tomando en cuenta tanto las incertidumbres en las lecturas de la señal instrumental como las involucradas en la preparación de las concentraciones de los calibradores. Los valores característicos del plomo para una muestra de sangre fueron: 3.02 μg/dL, con incertidumbre 0.15 μg/dL, con un intervalo de cobertura 2.74 μg/dL a 3.29 μg/dL. Los resultados obtenidos aplicando la ley de propagación de las incertidumbres a partir del modelo clásico de calibración ponderado, fueron los siguientes: 3.08 μg/dL, incertidumbre 0.042, intervalo de cobertura de 3.00 a 3.16 μg/dL. Se observó que hay mayor incertidumbre en el método numérico. No obstante, son coherentes con resultados experimentales de una muestra de sangre.DOI: http://dx.doi.org/10.5377/universitas.v4i1.1675
Modeling of Tests of Primary Water Stress Corrosion Cracking of Alloy 182 of Pressurized Water Reactor According to EPRI and USNRC Recommendations
Authors: Aly Omar Fernandes , Neto Miguel Mattar , De Abreu Mendonça Schvartzman Mônica Maria , Lima Luciana Iglésias Lourenço 
Published: December 2014

One of the main degradation mechanisms which cause risks to safety and reliability of pressurized water nuclear reactors is the primary water stress corrosion cracking (PWSCC) in nickel alloys, such as Alloy 600 (75Ni-15Cr-9Fe), and its weld metal Alloy 182 (67 Ni-15Cr-8Fe). It can appear at several reactor nozzles dissimilarly welded with Alloys 182/82 between steel ASTM A-508 G3 and stainless steel AISI316L, among others. The hydrogen which is dissolved to primary water to prevent radiolysis, can also have influence on the stress corrosion cracking behavior. In this article one departs from a study of Lima based in experimental data obtained from CDTN-Brazilian Nuclear Technology Development Center, in slow strain rate test (SSRT). It was prepared and used for tests a weld in laboratory, similar to dissimilar weld in pressurizer relief nozzles, operating at Brazilian NPP Angra 1. It was simulated for tests, primary water at 325oC and 12.5 MPa containing levels of dissolved hydrogen: 2, 10, 25, and 50 cm3 STP H2/kgH2O. The objective of this article is to propose an adequate modeling based on these experimental results, for PWSCC crack growth rate according to the levels of dissolved hydrogen, based on EPRI-MRP-263 NP. Furthermore, it has been estimated the stress intensity factor applied for these tests: according with these, some another models described on EPRI-MRP-115, and an USNRC Technical Report, have been tested. According to this study, CDTN tests are adequate for modeling comparisons within EPRI and USNRC models.
Chalcophile behavior of thallium during MORB melting and implications for the sulfur content of the mantle
Authors: Nielsen Sune G. , Shimizu Nobumichi , Lee Cin‐Ty A. , Behn Mark D. 
Published: December 2014

AbstractWe present new laser ablation ICP‐MS trace element concentration data for 28 elements in 97 mid‐ocean ridge basalt (MORB) glasses that cover all major spreading centers as well as Tl concentration data for all mineral phases in five lherzolites from the Lherz massif, France. The ratio between the elements thallium (Tl) and cerium (Ce) is nearly constant in MORB, providing evidence that the depleted MORB mantle (DMM) has uniform Ce/Tl. Lherzolite mineral data reveal that sulfides are heterogeneous and contain between 23 and 430 ng/g of Tl while all other minerals contain Tl below the analytical detection limit of ∼1 ng/g. We argue that Tl in MORB is controlled by residual sulfide during mantle melting. To investigate the observed relationship between Tl and Ce, we conduct models of fractional mantle melting, which show that the constant Ce/Tl in MORB is only reproduced if the ratio between clinopyroxene and sulfide in the upper mantle varies by less than 10%. In addition, the rate of melting for these two phases must be nearly identical as otherwise melt depletion and refertilization processes would lead to Ce/Tl fractionation. These model results allow us to establish a relationship for the sulfur content of DMM: [S]DMM = SCSS × Mcpx /Rcpx, where SCSS is the sulfur concentration of a silicate melt at sulfide saturation, Rcpx is the melt reaction coefficient, and Mcpx is the modal abundance of clinopyroxene in the DMM. Using this equation, we calculate that the average upper mantle sulfur concentration is 195 ± 45 μg/g.
Design, synthesis, and photosensitive performance of polymethacrylate‐positive photoresist‐bearing o‐nitrobenzyl group
Authors: Guo Lingxiang , Guan Jing , Zhao Xiaofang , Lin Baoping , Yang Hong 
Published: December 2014

ABSTRACTNovel polymethacrylate‐positive photoresist‐bearing o‐nitrobenzyl group was described herein. The matrix polymer (PCHIBNB) was synthesized by copolymerization of cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBMA), and o‐nitrobenzyl methacrylate (NBMA) via reversible addition fragmentation chain transfer (RAFT) polymerization method. After UV irradiation, the o‐nitrobenzyl groups of PCHIBNB were photocleaved and the resulting carboxyl groups were highly alkali‐soluble, so that the matrix polymer could be etched by mild alkali solution with no requirements of photosensitizers or photoacid generators. PCHIBNB was characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H‐NMR) spectroscopy, and gel permeation chromatography (GPC). The photocleavable behaviors of PCHIBNB were determined by FTIR, 1H‐NMR, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) analysis. The resist formulated with this polymer and cast in tetrahydrofuran (THF) solution showed 10 μm × 10 μm square pattern using a mercury–xenon lamp in a contact printing mode and tetramethyl‐ammonium hydroxide aqueous solution as a developer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41733.
Investigating the reduction in the absorption intensity of P3HT in polymer/fullerene “bilayers” coated using orthogonal solvents
Authors: Zhang Chunmei , Hu Yufeng , Tang Aiwei , Deng Zhenbo , Teng Feng 
Published: December 2014

ABSTRACTWe investigated the reduction in the absorption intensity of poly(3‐hexylthiophene) (P3HT) in a poly(3‐hexylthiophene)/(6,6)‐phenyl‐C61‐butyric acid methyl ester (P3HT/PCBM) “bilayer” heterojunction film that was fabricated using orthogonal solvents. The results show that even though P3HT is insoluble in dichloromethane (DCM), DCM could decrease the chain packing and the crystallinity of the P3HT film by the swelling effect. DCM also assists in the penetration of the PCBM into the P3HT underlayer during spin‐coating. After the DCM evaporates, the PCBM in the P3HT matrix hinders the self‐reorganization of P3HT, causing a drop in the absorption intensity of P3HT. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41757.
Enhancing performance of optical sensor through the introduction of polystyrene and porous structures
Authors: Panawong Chonnakarn , Pandhumas Thidarat , Youngme Sujittra , Martwiset Surangkhana 
Published: December 2014

ABSTRACTSimple and promising approaches for developing high‐performance Fe3+ sensors were proposed. Polyvinyl chloride (PVC) membrane containing pyrene as a fluorescent indicator was prepared via solvent‐cast method. Upon immersion into 1.0 mM Fe3+ solution, the fluorescence emission of the membrane decreased with the ratio of fluorescence intensities before and after (F0/F) immersion of 1.25. The sensitivity enhancement was achieved through the introduction of polystyrene (PS) onto PVC and the introduction of porous structures. Polyvinyl chloride‐graft‐polystyrene copolymers (PVC‐g‐PS) were synthesized via Atom Transfer Radical Polymerization using PVC as macroinitiator. The grafting percentages of PS on PVC calculated from Nuclear Magnetic Resonance Spectroscopy were 17 and 41. The membrane prepared from low molecular weight copolymer showed higher sensing ability than that from PVC with the F0/F value of 1.39. The increase in PS chain length did not significantly affect the fluorescence quenching. A Stern–Volmer quenching relationship was found with Ksv of 3.96 × 102 M−1. The effect of porous structures on fluorescence quenching was studied by introducing Triton X‐100 as a porogen to PVC/pyrene solution. Attenuated total reflection Fourier transform infrared spectroscopy and Scanning Electron Microscopy analyses confirmed a complete removal of Triton X‐100 after 3 days of immersion in water. The porous membrane demonstrated an enhanced sensing performance with the F0/F value of 1.46. PVC‐g‐PS/pyrene membrane exhibited highly sensitive and selective responses toward Fe3+ over Cu2+, Mg2+, Co2+, Zn2+, Ni2+, and Ag+. In addition, a good reversibility after five cycles of quenching and regeneration was obtained. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41759.
Mechanistic and conformational studies on the interaction of sulfamethazine with human immunoglobulin G by molecular modeling and multi‐spectroscopic approach in vitro
Authors: Wang Qin , Ge Hongguang , Liu Cunfang , Zhang Shengrui , Tian Guanghui 
Published: December 2014

AbstractBinding interaction of sulfamethazine (SMZ) with human immunoglobulin G (HIgG) has been explored under physiological conditions. The interaction mechanism was firstly predicted through molecular modeling which showed that several hydrogen bonds participated in stabilizing the SMZ − HIgG complex. Fluorescence spectroscopy, ultraviolet–visible (UV–vis) light absorption and circular dichroism (CD) spectroscopy were used to analyze the binding site, binding constants and effects of SMZ on HIgG stability and secondary structure. The binding parameters and thermodynamic parameters at different temperatures for the reaction have been calculated according to the Scatchard, Sips and Van 't Hoff equations, respectively. Experimental results showed that the quenching mechanism was a static quenching and there was one independent class of binding site on HIgG for SMZ during their interaction. The thermodynamic parameters of the reaction, namely standard enthalpy ΔH0 and entropy ΔS0, had been calculated to be −19.12 kJ · mol−1 and 20.22 J · mol−1 · K−1, respectively, which meant that the electrostatic interaction was the predominant intermolecular force in stabilizing the SMZ − HIgG complex. Moreover, the conformational changes of HIgG in the presence of SMZ were confirmed by three‐dimensional fluorescence spectroscopy, UV–vis absorption spectroscopy and CD spectroscopy. Copyright © 2014 John Wiley & Sons, Ltd.
A liquid chromatography–tandem mass spectrometric assay for the antihypertensive agent azelnidipine in human plasma with application to clinical pharmacokinetics studies
Authors: Gao Yanhui , Li Baoqiu , Zhu Baomeng , Liu Dongming , Zhao Hengli , Fang Zengjun , Wang Haisheng , Lou Hongxiang 
Published: December 2014

AbstractA robust and sensitive high‐performance liquid chromatographic–tandem mass spectrometric (HPLC‐MS/MS) assay for the high‐throughput quantification of the antihypertensive drug azelnidipine in human plasma was developed and validated following bioanalytical validation guidelines. Azelnidipine and internal standard (IS), telmisartan, were extracted from human plasma by precipitation protein and separated on a C18 column using acetonitrile–methanol–ammonium formate with 0.1% formic acid as mobile phase. Detection was performed on a turbo‐spray ionization source (ESI) and mass spectrometric positive multiple reaction monitoring mode (+MRM) using the respective transitions m/z 583.3 → 167.2 for azelnidipine and m/z 515.3 → 497.2 for IS. The method has a wide analytical measuring range from 0.0125 to 25 ng/mL. For the lowest limit of quantitation, low, medium and high quality controls, intra‐ and interassay precisions (relative standard deviation) were 3.30–7.01% and 1.78–8.09%, respectively. The drug was sufficiently stable under all relevant analytical conditions. The main metabolite of azelnidipine, M‐1 (aromatized form), was monitored semiquantitatively using the typical transition m/z 581.3 → 167.2. Finally, the method was successfully applied to a clinical pharmacokinetic study in human after a single oral administration of azelnidipine 8 mg. The assay meets criteria for the analysis of samples from large research trials. Copyright © 2014 John Wiley & Sons, Ltd.
A rare cause of ascites: pseudomyxoma peritonei and a review of the literature
Authors: Chauhan Abhishek , Patodi Nishant , Ahmed Monz 
Published: December 2014

Key Clinical MessagePseudomyxoma peritonei is rare. The rarity is highlighted by the lack of published evidence regarding management. The latest treatments have altered the prognosis of a once incurable disease. This report serves to both raise awareness and critically appraise the literature regarding the latest management.
Ultrasonic Hot Embossed Polymer Microreactors for Optical Measurement of Chemical Reactions
Authors: Tollkötter Alexander , Sackmann Johannes , Baldhoff Tobias , Schomburg Werner Karl , Kockmann Norbert 
Published: December 2014

AbstractUltrasonic hot embossing of polymers is an alternative to reduce fabrication costs of microreactors. An ultrasonic welding machine is used to melt a stack of thermoplastic foils and adapting them to a short‐time milled aluminum mold showing the inversed design of the desired microfluidic cavities. Two micromixers were fabricated this way providing a low degree of axial dispersion and pressure loss. Stability analysis is successfully performed for a wide temperature range and high pressure. Mixing of colored aqueous solutions and neutralization reactions are implemented to both systems for defined volume flow rates and optically investigated via microscope. Reaction progress is automatically determined with a MATLAB script by reference to the consequential color change of the neutralization reaction with a color indicator. Typical mixing characteristics are identified for both mixers.
Tracing Seismic Shortest Path Rays in Anisotropic Medium with Rolling Surface
Authors: Hou‐Yue ZHAO , Mei‐Gen ZHANG 
Published: December 2014

AbstractIt has very important theoretical and practical values to take rolling surface and seismic anisotropy into consideration in seismic forward modeling and inversion. Based on previous researches, the shortest path calculation algorithm is introduced in this paper to calculate seismic travel times in anisotropic media with rolling surface. In the process of model gridding, the whole model is divided into square cells firstly and rolling boundary is regarded as the approximation of units with irregular shapes. Then shortest path calculation is achieved on irregular grids by setting irregular nodes. Sena's group velocity approximation is used to calculate seismic travel times in anisotropic media during ray tracing, and seismic shortest path ray tracing in a complex anisotropic medium with rolling surface is achieved in the end. Theoretical model calculations show that the method in this paper can be reliably applied to complex anisotropic models with higher calculation accuracy.
Dispersion Analysis of Triangle‐Based Finite Element Method for Acoustic and Elastic Wave Simulations
Authors: Shao‐Lin LIU , Xiao‐Fan LI , You‐Shan LIU , Tong ZHU , Mei‐Gen ZHANG 
Published: December 2014

AbstractAcoustic and elastic wave equations are discretized by finite element method with triangles and central difference scheme in space and time, respectively. The generalized eigenvalue problems are constructed to analyze the numerical dispersion of the finite element method. Three types of mass finite element method, which are consistent finite element method (CFEM), lumped finite element method (LFEM) and mixed finite element method (MFEM), are implemented to the numerical scheme, and the numerical dispersion is under a comprehensive study. Then, the MFEM is adopted to investigate the behavior of numerical anisotropy in terms of four typical triangle meshes. Comparing the numerical dispersion and anisotropy behavior when MFEM uses different interpolation orders, one can easily find that numerical error decreases as the interpolation order increases. Specifically, the numerical dispersion and anisotropy are negligible when third‐order interpolation is used. Finally, controlling the other impact factors, the dispersive properties of elastic wave propagation in elastic medium with various velocity ratios are analyzed, and the results of numerical dissipation are presented at the end of this paper.
Automatic Event Detection and Event Recovery in Low SNR Microseismic Signals Based on Time‐Frequency Sparseness
Authors: Peng WANG , Xu CHANG , Yi‐Bo WANG , Lu‐Chen WANG , Hong‐Yu ZHAI 
Published: December 2014

AbstractMicroseismic monitoring is an effective tool for evaluating the fracturing process and its final results. Event detection is the first step of this monitoring. However, for low SNR microseismic monitoring records, it is difficult to obtain satisfactory results using conventional detection methods. According to time‐frequency sparsness of microseismic events, the Renyi entropy method is used to measure sparseness of microseismic monitor records. A target function of event detection is created which takes the number of low entropy value traces as thresholding under time‐frequency constraint conditions. This method can detect microseismic events and restore clearer microseismic events simultaneously. Tests on synthesis data and real records show that this method has a good performance in processing low‐SNR microseismic records.
Integrated Analysis of Well Logs and Seismic Data to Deduce the Possible Distribution in Depth of Gas Hydrate in Shenhu Area, South China Sea
Authors: Hua‐Ning XU , Guang‐Xue ZHANG , Xiao‐Dong ZHENG , Ming‐Jun WANG , Sheng‐Xiong YANG , Rui YANG , Bei‐Wen LIANG 
Published: December 2014

AbstractThe available geological and geophysical information indicates the presence of gas hydrate at Shenhu Area of Northern South China Sea. The drilling cores recovered in 2007 testify the expectation and reveal that the gas hydrate disseminates evenly within the hydrate stable zone (HSZ), but its regional distribution is inhomogeneous. However, the logging record length and coring depth coverage are limited, which causes the depth distribution of gas hydrate to be indeterminate. Logs at well site SH7 were used to link the information of physical properties of sediments to the coincident seismic data acquired in this area. According to the relation between physical properties of sediments and seismic reflection characteristics, three primary formations were calibrated and the pseudo‐well constrained impedance inversion was then applied on post‐stack seismic data. The results showed a high velocity zone below the interval bearing gas hydrate. To determine whether this high velocity zone is related to the occurrence of gas hydrate or not, the technique of AVO forward modeling was further used to analyze the reflecting characteristic of pre‐stack seismic data. The comparison between synthetic seismic models and real seismic data indicates that the HSZ was composed of thin interbeds of gas hydrate‐bearing sediments and water‐saturated sediments, which suggests that another gas hydrate deposit exists most likely below the depth where gas hydrate‐bearing sediments were cored in the hole.
Power allocation in the energy harvesting full‐duplex Gaussian relay channels
Authors: Feghhi Mahmood Mohassel , Mirmohseni Mahtab , Abbasfar Aliazam 
Published: December 2014

SummaryIn this paper, we propose a general model to study the full‐duplex non‐coherent (NC) decode‐and‐forward Gaussian relay channel (RC) with energy harvesting (EH) nodes, called NC‐EH‐
, in three cases: (i) no energy transfer (ET), (ii) one‐way ET from the source (S) to the relay (R), and (iii) two‐way ET. We consider the problem of optimal power allocation in NC‐EH‐
in order to maximize the total transmitted bits from S to the destination in a given time duration. General stochastic energy arrivals at S and R with known EH times and values are assumed. In NC‐EH‐
with no ET, the complicated min‐max optimization form along with its constraints make the problem intractable. It is shown that this problem can be transformed to a solvable convex form; however, convex optimization solution does not provide the structural properties of the optimal solution. Therefore, following an alternative perspective, we investigate conditions on harvesting process of S and R where we find optimal algorithmic solution. Further, we propose some suboptimal algorithms and provide some examples, in which the algorithms are optimal. Moreover, we find a class of problems for NC‐EH‐
with one‐way ET from S to R, where the optimal algorithmic solution is devised. For NC‐EH‐
with two‐way ET, we propose general optimal algorithmic solution. Furthermore, the performance of the proposed algorithms are evaluated numerically and compared with optimal numerical convex optimization tools. Copyright © 2014 John Wiley & Sons, Ltd.