bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polysulfones with chelating groups for heavy metals retention
Authors: Albu Raluca Marinica , Avram Ecaterina , Stoica Iuliana , Ioan Silvia 
Published: March 2012

AbstractThe formation conditions of new quaternized polysulfones with chelating groups (methyl 3‐pyridyl ketone) (KQPSF) and the major factors influencing the retention process of copper ions were analyzed by attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy, environmental scanning electron microscopy, and differential scanning calorimetry. The investigations showed that the percentage of copper ions retained by KQPSF increases by increasing both the time of immersion in a CuCl2·2H2O aqueous solution, and molarity, the maximum value being attained on immersion for 48 h, at a temperature of 60°C and a molarity of 1.5 M. It can be concluded that methyl 3‐pyridyl ketone might be used for obtaining complex polysulfone structures employed by multiple applications, including wastewater purification. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers
Comparative study of the thermal and mechanical properties of nanocomposites prepared by in situ polymerization of ε‐caprolactone and functionalized carbon nanotubes
Authors: Antolín‐Cerón Víctor H. , Gómez‐Salazar Sergio , Rabelero Martin , Soto Víctor , Luna‐Bárcenas Gabriel , Katime Issa , Nuño‐Donlucas Sergio M. 
Published: March 2012

AbstractAs an effort to compare the influence of several types of functionalized carbon nanotubes (CNTs) upon the mechanical and thermal properties of nanocomposites prepared with a poly(ε‐caprolactone) (PCL) as matrix and functionalized CNTs as fillers; nanocomposites of PCL–CNTs were studied in this study. CNTs were synthesized by chemical vapor deposition using dry ethanol as the carbon source. High resolution scanning electron microscopy, high resolution transmission electron microscopy, and Raman and infrared spectroscopies were used to characterize the CNTs obtained. Four chemical synthesis routes were exploited to add different types of chemical groups onto the surface of purified CNTs. Specifically, the authors inserted: (i) N‐methylpyrrolidine, (ii) carboxyl and hydroxyl, (iii) urethane, and (iv) phenylmethanol groups onto CNTs surface. Nanocomposites were synthesized by in situ polymerization of ε‐caprolactone (ε‐CL) in presence of 1 wt% of each type of functionalized CNTs. Young's moduli of the nanocomposites prepared with N‐methylpyrrolidine or carboxyl and hydroxyl functionalized CNTs are higher than the one of pure PCL, whereas all the mechanical properties of the nanocomposites containing urethane or phenylmethanol groups evaluated at the break point were higher than those of pure PCL. Thermal stability of all the nanocomposites studied improved with respect to pure PCL. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers
Investigation of molecular interaction between single‐walled carbon nanotubes and conjugated polymers
Authors: Zaminpayma Esmaeil , Mirabbaszadeh Kavoos 
Published: March 2012

AbstractSingle‐walled carbon nanotubes (SWNTs) have unique properties such as high electrical conductivity and high tensile strength. Their composites with polymers have a great role in new sciences such as organic solar cells and ultrastrong lightweight materials. In this article, molecular dynamic simulations with polymer consistent force field are performed to study the interaction between SWNTs and conjugated polymers including poly(2‐methoxy‐5‐(3‐7‐dimethyloctyloxy)‐1,4‐phenylenevinylene) (MDMO‐PPV), poly(3‐hexythiophene) (P3HT), and poly[(9,9′‐dioctylfluorenyl‐2,7‐diyl)‐co‐bis(N,N′‐(4,butylphenyl))bis(N,N′‐phenyl‐1,4‐phenylene)diamine] (PFB). We computed the interaction energy and morphology of polymers adsorbed to the surface of SWNTs was studied by the radius of gyration (Rg). The influence of important factors such as SWNT radius, chirality, and the temperature on the interfacial adhesion of SWNT–polymer and Rg of polymers were studied. We found that the strongest interaction between the SWNTs and these polymers was, first observed for P3HT, then MDMO‐PPV, and finally PFB. Our results showed that the interaction energy is influenced by SWNT radius and the specific monomer structure of the polymers, but the effects of chirality and temperature are very weak. In addition, we found that the temperature, chirality, and radius have not any important effect on the radius of gyration. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers
Preparation, characterization and electromagnetic properties of polyaniline/carbon nanotubes/nickel ferrite nanocomposites
Authors: El‐Shishtawy Reda M. , Salam M. Abdel , Gabal M.A. , Asiri Abdullah M. 
Published: March 2012

AbstractNew electromagnetic nanocomposites were prepared from polyaniline (PANI)/oxidized single‐walled carbon nanotubes (OxSWCNTs)/NiFe2O4 by in situ polymerization of aniline using hexanoic acid as a soft template. OxSWCNT and NiFe2O4 were prepared first so as to be used in the formulation of PANI composites. Transmission electron microscope (TEM) results revealed the formation of PANI nanoparticles of 60 nm diameter, OxSWCNT of 24 nm, and NiFe2O4 of 54 nm. Also, TEM image of the ternary composite indicated agglomerative coating of PANI appearing as a gray shells and black core of NiFe2O4 with widening the diameter of OxSWCNT to be around 66 nm. Dc conductivity was measured as a function of temperature. Magnetic susceptibility was measured as a function of temperature and magnetic field intensity. All samples revealed NiFe2O4‐dependent ferromagnetism. The activation energies for dc conductivity suggest that the conductivity is owing to hopping conduction mechanism. A synergistic effect between NiFe2O4 and PANI/OxSWCNT is observed. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers
Characterizing the Protocol for Early Modified Constraint‐induced Movement Therapy in the EXPLICIT‐Stroke Trial
Authors: Nijland Rinske , van Wegen Erwin , van der Krogt Hanneke , Bakker Chantal , Buma Floor , Klomp Asbjørn , van Kordelaar Joost , Kwakkel Gert ,   on behalf of the EXPLICIT‐stroke consortium
Published: March 2012

AbstractConstraint‐induced movement therapy (CIMT) is a commonly used rehabilitation intervention to improve upper limb function after stroke. CIMT was originally developed for patients with a chronic upper limb paresis. Although there are indications that exercise interventions should start as early as possible after stroke, only a few randomized controlled trials have been published on either CIMT or modified forms of CIMT (mCIMT) during the acute phase after stroke. The implementation of (m)CIMT in published studies is very heterogeneous in terms of content, timing and intensity of therapy. Moreover, mCIMT studies often fail to provide a detailed description of the protocol applied. The purpose of the present paper is therefore to describe the essential elements of the mCIMT protocol as developed for the EXplaining PLastICITy after stroke (EXPLICIT‐stroke) study. The EXPLICIT‐stroke mCIMT protocol emphasizes restoring body functions, while preventing the development of compensatory movement strategies. More specifically, the intervention aims to improve active wrist ‐and finger extension, which is assumed to be a key factor for upper limb function. The intervention starts within 2 weeks after stroke onset. The protocol retains two of the three key elements of the original CIMT protocol, that is, repetitive training and the constraining element. Repetitive task training is applied for 1 hour per working day, and the patients wear a mitt for at least 3 hours per day for three consecutive weeks. Copyright © 2012 John Wiley & Sons, Ltd.
Chiral second‐harmonic generation from small organic molecules at surfaces
Authors: Persechini L. , McGilp J. F. 
Published: March 2012

AbstractThe molecules of life are chiral. Advanced materials for heterogeneous enantioselective catalysis and biomolecular sensing and recognition will need nanoscale chiral structures, and methods of characterizing them. Optical circular dichroism (CD) is the main technique for probing chiral molecules in solution. Amino acids are levorotatory, but CD cannot detect chirality in ultrathin films of these small molecules at surfaces, as the response is too weak. Chiral second‐harmonic generation (SHG) from ultrathin layers of larger, more polarizable organic molecules has been detected at silica surfaces, where the presence of electronic resonances enhanced the signal. Here chiral SHG is reported from ultrathin films of 1,1′‐binaphthalene‐2,2′‐diol (binol) and cysteine. The SH response from the different chiral enantiomers was measured away from resonance, using unamplified femtosecond excitation at 800 nm, by rotating a quarter‐wave plate polarizer, and detecting the p‐polarized SH output. The SH response from the molecules is measurable and differs significantly between the enantiomers. Simultaneous fitting of the polarizer rotation plots, using a simple phenomenological model, produces reasonable agreement with the experimental results. This exploratory work shows that SHG has sufficient sensitivity to detect the chirality of small molecules adsorbed on surfaces.
Quantum state tomography measurements on strain‐tuned InxGa1−xAs/GaAs quantum dots
Authors: Jöns K. D. , Hafenbrak R. , Atkinson P. , Rastelli A. , Schmidt O. G. , Michler P. 
Published: March 2012

AbstractWe present quantum state tomography (QST) measurements on strain‐tuned self‐assembled InxGa1−xAs/GaAs quantum dots. By applying uniaxial stress we tune the fine structure splitting (FSS) of the exciton transition and investigate the change in the two‐photon polarization state (TPPS) of the quantum dot. We tune the FSS to a minimum value of 4.7 µeV. The density matrix of the TPPS indicates an onset of the anti‐crossing of the exciton transition. Our experiments show that strain‐tuning is a promising method for the generation of triggered polarization entangled photon pairs.
Magnetic properties in semifluorinated GaN sheet from first principles calculations
Authors: Xiao Wen‐Zhi , Wang Ling‐Ling , Luo Hai‐Jun , Yang Jian‐Yu 
Published: March 2012

AbstractBased on first‐principles spin‐polarized density functional theory calculations, the relative stability, electronic structures, and magnetic properties of semi‐fluorinated gallium nitride (GaN) sheets are investigated. The most stable conformation exhibits ferromagnetic (FM) ground state with a magnetic moment of about 1.0µB per fluorine. The half‐metallic ferromagnetism is mainly attributed to the charge transfers from N to F atoms. Fluorination leads to unpaired spins in N‐2pz states and unsaturated F‐2p orbitals. The hole‐mediated double exchange is responsible for the ferromagnetism in GaN sheets. In addition, GaN nanoribbons (GaNNRs) fluorinated only Ga edges are FM. This opens a route toward metal‐free magnetic materials which have a huge possibility of making spintronic devices and nanomagnets.
Electronic activity in chelotropic and cycloaddition reactions
Authors: Correa José V. , Jaque Pablo , Geerlings Paul , Toro‐Labbé Alejandro 
Published: March 2012

AbstractUsing the reaction electronic flux, a new tool aimed at identifying and characterizing the electronic activity taking place during a chemical process, the chelotropic and cycloaddition reactions of 1,3–butadiene with sulfur dioxide are revisited. The mechanisms of both reactions were studied within the framework of the reaction force analysis; the electronic activity determined through the reaction electronic flux was rationalized in terms of chemical events, bond forming or breaking processes, and polarization and transfer effects localized on the reactants species. The results show interesting features and differences between both the mechanisms; while the chelotropic path is driven by through space electrostatic interactions, the cycloaddition reaction is mainly driven by through bond electronic activity. The relation between these findings and the experimentally found kinetic (cycloaddition) and thermodynamic (chelotropic reaction) control is discussed. Int J Quantum Chem, 2012. © 2012 Wiley Periodicals, Inc.
A mass spectrometric investigation of isomers of butane
Authors: Yılmaz Alıç Tuğbahan , Kılıç Hamdi Şükür , Durmuş Haziret , Doğan Mevlüt , Ledingham Ken W. D. 
Published: March 2012

RATIONALEButane is an important industrial chemical in which photo‐processes are very important for the initiation of reactions. Recent advances in nanosecond pulsed laser technology have led to high laser intensities being available to researchers to enable these photo‐processes to be studied in compounds such as butane.METHODSThe photo‐decomposition, dissociation and combustion mechanisms in the neutral butane molecule have been studied in detail, by investigating the multiphoton (MP) dissociative ionisation of its n‐ and i‐isomers, using a time‐of‐flight mass spectrometer connected to a high power nanosecond laser system. The laser used was a Nd:Yag with a 5 ns pulse width operated at the fundamental wavelength (1064 nm) and the doubled and tripled wavelengths (532 nm and 355 nm). The fragmentation patterns for the isomers were determined for the three wavelengths as a function of laser intensity. Similar laser intensities of between 1010 and 1013 W/cm2 were used at the three wavelengths: 1064, 532 and 355 nm.RESULTSThe mass spectra of each isomer of the butane molecule display a very weak molecular ion and are dominated by fragment ion peaks. The degree of fragmentation increases as the laser intensity increases.CONCLUSIONSDepending on the wavelength some significant differences in the mass spectra of the two isomers were detected and it has been concluded that the isomerisation of i‐butane to n‐butane is a process which is faster than the duration of the laser pulse used. Copyright © 2012 John Wiley & Sons, Ltd.
The Moderating Effects of Stress and Rumination on Depressive Symptoms in Women and Men
Authors: Mezo Peter G. , Baker Robyn M. 
Published: March 2012

AbstractAlthough there is an abundance of research linking stress and rumination to depression in women, little is known with respect to the role stress plays in the relationship between rumination and depression. Moreover, the role of stress in the rumination–depression relationship has not been previously investigated separately in women. In the present study, 301 undergraduate women and 109 undergraduate men were administered a questionnaire battery to assess their degrees of stress, depressive symptoms and ruminative tendencies. Individually, both stress and rumination scores were found to account for a large proportion of variance in depressive symptom scores. The interaction of stress and rumination also accounted for a significant proportion of this variance, suggesting a significant moderating effect of stress on the rumination–depressive symptom relationship in women and men. Furthermore, women and men with the highest degrees of stress demonstrated the strongest rumination–depressive symptom relationship. However, low‐stress women and low‐stress men demonstrated divergent patterns of relationships. The alternative model of rumination as a moderator of the stress–depression relationship likewise supported divergent relationships between low‐rumination women and low‐rumination men in the relationship between stress and depression. The implications of these findings regarding vulnerability to depressive symptoms are discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Static and Cyclic Deformation Behavior of the Ferritic Steel 16Mo3 Under Monotonic and Cyclic Loading at High Temperatures
Authors: Hoffmann Markus , Biermann Horst 
Published: March 2012

AbstractThe ferritic steel 16Mo3 is commonly used for heat exchangers and steam generators. The temperature loading conditions for these applications range typically from 200 to 500°C. For a basic characterization of the steel 16Mo3, the properties were determined by means of tensile tests with different strain rates. At 200 and 300°C, a negative strain‐rate sensitivity was observed which is due to dynamic strain ageing (Portevin–LeChâtelier effect). To characterize the low cycle fatigue (LCF) behavior of this steel, isothermal strain‐controlled LCF tests were carried out at 200 and 500°C at different strain amplitudes. The cyclic stress response curves are showing principally different courses at the investigated temperatures. The stress relaxation behavior was obtained by cyclic load enhancement tests at various strain amplitudes with dwell times of 30 and 120 s.
Effect of Isothermal Bainite Treatment on Microstructure and Mechanical Properties of Low‐Carbon TRIP Seamless Steel Tube
Authors: Zhang Zicheng , Manabe Ken‐ichi , Li Yanmei , Zhu Fuxian 
Published: March 2012

AbstractIn this work, a low‐carbon transformation‐induced‐plasticity (TRIP) seamless steel tube (Fe–0.15C–1.34Si–1.45Mn–0.029Nb–0.024Ti, in wt%), having potential in application of hydroforming process, has been successfully manufactured by using piercing, cold‐drawing, and two‐stage heat‐treatment process. The optimal heat‐treatment conditions, inter‐critical annealing (IA), and isothermal bainite treatment (IBT) were firstly obtained to maximize the volume fraction and stability of the retained austenite (RA). The effects of temperature and holding time IBT on the microstructures of the TRIP steel tube were studied via optical microscopy (OM), scanning microscopy (SEM), transmission electron microscopy (TEM), and X‐ray diffractometer (XRD). The mechanical properties in the axial direction and hydroformability were also evaluated by conventional tensile test and flaring test, respectively. Two‐stage heat‐treatment was finally performed to achieve the required mechanical properties for the hydroformed tube. The results shows that the RA volume fraction increased at first and then decreased with the increase of IBT holding time and IBT temperature for a particular set of IA temperature and IA holding time. It was also demonstrated that high tensile strength of 618 MPa, total elongation of 35.5%, n‐value of 0.23, and better hydroformability could be successfully produced in this TRIP steel tube at IA temperature of 800°C, holding for 10 min, and IBT of 410°C for 4 min holding time.
Multipath traffic balancing approach for disconnection reduction in video games over mobile ad hoc networks
Authors: Kaiser Arnaud , Achir Nadjib , Boussetta Khaled 
Published: March 2012

ABSTRACTIn this work, we aim to improve the gameplay of time‐sensitive video games over mobile ad hoc networks (MANETs). We focus on the disconnection problems. Precisely, when the path between a player and the game server fails, the game on the player side freezes and becomes unplayable until the network re‐establishes a new path toward the game server. In MANETs, disconnections occur mainly because of node mobility. To overcome this problem, we propose a multipath approach that we combine with an adaptive traffic balancing algorithm. Precisely, for each source–destination couple, we maintain two Optimized Link State Routing paths using the end‐to‐end delay metric. Each path carries a proportion of the game traffic. Our traffic balancing algorithm relies on path robustness estimation to dynamically balance the game traffic between the two paths. The results of our experiments, which are based on a real implementation of our proposals, show that using multipath routing with traffic balancing among different paths reduces route failures and improves the gameplay experience. Copyright © 2012 John Wiley & Sons, Ltd.
Joint optimization of source and relay precoding in non‐regenerative MIMO relay systems
Authors: Zhang Yang , Li Jiandong , Pang Lihua , Ding Zhi 
Published: March 2012

ABSTRACTWe investigate the problem of precoding optimization in an amplify‐and‐forward multiple‐input‐multiple‐output relay system. Most reported works on this problem focus chiefly on the design of relay precoder without simultaneously optimizing the direct link. In this paper, we propose a method for joint source/relay precoder design, taking both direct and relay links into account. Our design is based on maximizing the mutual information (MI) under limited transmission power constraints at the source and relay, respectively. We first formulate a constrained optimization problem before relaxing the original cost function for tractability and derive a MI lower bound. This elaborate bound can asymptotically approach the exact expression of MI in an iterative fashion. In contrast to previous strategies, we then prove that the optimal structure of the source and relay precoders jointly convert the multiple‐input‐multiple‐output relay channel into a bank of single‐input‐single‐output relay channels without having to assume a beamforming structure to simplify the derivation. Specifically, the linear precoding design problem degenerates into power loading among multiple single‐input‐single‐output relay channels. Applying standard Lagrange technique results in a scalar convex optimization, and it can be readily solved by iterative water filling. Numerical examples demonstrate that the proposed scheme, either exploiting partial or full channel state information, significantly outperforms the existing methods. Copyright © 2012 John Wiley & Sons, Ltd.
Eshelby‐Kröner self‐consistent elastic model: the geometric mean versus the arithmetic mean – A numerical investigation
Authors: Fréour S. , Fajoui J. 
Published: March 2012

AbstractScale‐transition models, such as Eshelby‐Kröner self‐consistent framework, which are often used for predicting the effective behavior of heterogeneous materials or estimating the distribution of local states from the knowledge of the corresponding macroscopic quantities, require the extensive use of set averages. The present paper is devoted to the comparison of the numerical results provided in pure elasticity by Eshelby‐Kröner model depending on the average type chosen for achieving set average operations: either the traditional arithmetic mean or the geometric average. Various numerical applications of the model to the case of predicting either the effective stiffness or the lattice strains of single‐phase polycrystals will be provided. The particular case when an extreme grain‐shape occurs will also be investigated.
Fortification of Potato Chips with Natural Plant Extracts to Enhance their Sensory Properties and Storage Stability
Authors: Rababah Taha M. , Feng Hao , Yang Wade , Yücel Sevil 
Published: March 2012

AbstractThis study evaluated the effectiveness of grape seed extracts (GSE), green tea extracts (GTE), or butylated hydroxytoluene (BHT) on lipid oxidation reduction of potato chips stored for up to 90 days. The highest (P ≤ 0.05) phenolic contents were detected in GSE (6134.5 mg gallic acid equivalent/100 g) followed by GTE and other plant extracts (oregano, thyme, terebinth, parsley, and bouncing bet). BHT had the greatest antioxidant activity (% inhibition) value (53.0) followed by GSE (42.6) and GTE (31.7). The GSE and GTE exhibited significantly higher antioxidant activities (measured by oxidative stability instrument) than the other plant extracts. The BHT and GSE at 1,000 ppm level was significantly the most effective in minimizing the peroxide value development during 90 days of storage. Descriptive results showed that higher levels of GSE and GTE (750 and 1,000 ppm) prevented the astringency development during 60 days of storage and minimized the off‐notes, i.e., astringency and rancidity, during 90 days of storage. The cardboard attribute was not noticed when GSE and GTE, and BHT were added at 750 and 1,000 ppm levels. The GSE and GTE have a great potential for use as natural antioxidants to preserve the potato chips.