bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibrational modes of rare‐earth formates
Authors: Silva E. N. , Moura M. R. , Ayala A. P. , Guedes I. , Polla G. , Vega D. R. , Tobia D. , Saleta M. E. 
Published: February 2009

AbstractIn this work we investigate the room‐temperature Raman spectra of several rare‐earth [RE(HCOO)3; RE = La, Pr, Nd, Gd, Tb and Y] formates. Polarized measurements were carried out for La(HCOO)3 yielding the observation of most of the Raman‐active phonons predicted by group theory analysis. The respective assignment is given based on the formate vibrations and correlations with previous results in other RE(HCOO)3 systems. The wavenumber ‘softening’ observed when RE goes from Y to La is accounted for the lattice expansion. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and Characterization of Large‐Core Star Polymers and Polymer Networks: Effects of Arm Length and Composition of the Cross‐Linking Mixture
Authors: Kafouris Demetris , Gradzielski Michael , Patrickios Costas S. 
Published: February 2009

AbstractLarge‐core star polymers (LCSPs) and polymer networks were prepared using sequential group transfer polymerization (GTP) for the synthesis of linear poly(methyl methacrylate) (polyMMA) arms, followed by their cross‐linking using a mixture of MMA monomer and ethylene glycol dimethacrylate (EGDMA) cross‐linker. High monomer/cross‐linker molar ratios and short arms favored the formation of polymer networks, whereas the opposite conditions favored the formation of LCSPs. LCSPs presented two populations: star polymers and covalently linked star polymer aggregates. The size of the non‐aggregated star polymers, and the size and fraction of the star polymer aggregates passed through a maximum as the amount of the monomer in the cross‐linking mixture increased. The degrees of swelling in tetrahydrofuran (THF) of the networks, the sol fraction extracted from them, and the percentage of linear polymer in the sol fraction increased as the degree of polymerization of the arms increased.magnified image
Porous Polymers: Enabling Solutions for Energy Applications
Authors: Thomas Arne , Kuhn Pierre , Weber Jens , Titirici Maria‐Magdalena , Antonietti Markus 
Published: February 2009

AbstractA new generation of porous polymers was made for various energy‐related applications, e.g., as fuel cell membranes, as electrode materials for batteries, for gas storage, partly from renewable resources. This review intends to catch this emerging field by reporting on a variety of different approaches to make high performing polymers porous. This includes template techniques, polymers with inherent microporosity, polymer frameworks by ionothermal polymerization, and the polymerization of carbon from appropriate precursors and by hydrothermal polymerization. In this process, we try to not only identify the current status of the field, but also point to open question and tasks to identify the potentially relevant progress.magnified image
R&D investment as a signal in corporate takeovers
Authors: Socorro M. Pilar 
Published: February 2009

AbstractThe purpose of this paper is to analyze the effects that takeover threats have on firms' preacquisition R&D intensity. Critics of takeovers usually argue that takeover threats may reduce target firms' R&D investments. However, I find that target firms may increase R&D investment in order to signal their compatibility with the acquiring firm. The identity of the acquired firm depends on the market size and target firms' efficiency and compatibility. Through R&D investments, target firms may affect this result, signaling potential outsiders the kind of competition they may face, and forcing them to accept lower takeover offers. Copyright © 2009 John Wiley & Sons, Ltd.
Flow‐induced disturbances in balanced steady‐state free precession images: Means to reduce or exploit them
Authors: Lagerstrand K.M. , Plewes D.B. , Vikhoff‐Baaz B. , Forssell‐Aronsson E. 
Published: February 2009

AbstractIn this work computer simulations and phantom measurements are presented that show the effect of flow on in‐plane balanced steady‐state free precession images. The images were studied for various flow velocities, excitation regions, relaxation times, RF‐pulse angles, and off‐resonance frequencies. The work shows that flow‐induced disturbances are present in the images, but can be reduced by the application of inhomogeneous excitation regions. Also, a velocity quantification method that utilizes the disturbances was developed and proved to quantify flow velocities accurately. The work concluded that the flow‐induced disturbances can be reduced to improve image quality, but can also be exploited to quantify the flow velocity. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Ultrashort T relaxometry for quantitation of highly concentrated superparamagnetic iron oxide (SPIO) nanoparticle labeled cells
Authors: Liu Wei , Dahnke Hannes , Rahmer Juergen , Jordan E. Kay , Frank Joseph A. 
Published: February 2009

AbstractA new method was developed to measure ultrashort T relaxation in tissues containing a focal area of superparamagnetic iron oxide (SPIO) nanoparticle‐labeled cells in which the T decay is too short to be accurately measured using regular gradient echo T mapping. The proposed method utilizes the relatively long T2 relaxation of SPIO‐labeled cells and acquires a series of spin echo images with the readout echo shifted to sample the T decay curve. MRI experiments in phantoms and rats with SPIO‐labeled tumors demonstrated that it can detect ultrashort T down to 1 ms or less. The measured T values were about 10% higher than those from the ultrashort TE (UTE) technique. The shorter the TE, the less the measurements deviated from the UTE T mapping. Combined with the regular T mapping, this technique is expected to provide quantitation of highly concentrated iron‐labeled cells from direct cell transplantation. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Reliability, validity and responsiveness of a new leisure index: The Patient‐Specific Leisure Scale (PSLS)
Authors: Wikström Ingegerd , Arvidsson Barbro , Nilsson Käth , Roos Ewa , Jacobsson Lennart T.H. 
Published: February 2009

AbstractObjectives: To investigate the reliability, validity and responsiveness of a new Patient‐Specific Leisure Scale (PSLS), constructed to identify goals and outcomes for individual patients with rheumatoid arthritis (RA).Methods: Forty‐nine patients with RA were used to evaluate test–retest reliability, and 100 consecutive RA patients were used for construct validity. Twenty‐five RA patients, commencing with treatment on tumour necrosis factor (TNF) inhibitors, were evaluated before the start and after three months of therapy, to test responsiveness. The most important leisure activity (as judged by the patients) was used when evaluating reliability and validity. The perceived difficulty with each activity was scored from 0 to 10 (0 = able to perform activity without difficulty, 10 = unable to perform activity).Results: Test–retest reliability indicated a good agreement (0.62–0.87) using weighted kappa. Construct validity was demonstrated by modest positive correlation between leisure activity and Health Assessment Questionnaire (HAQ) (rs = 0.27, p = 0.005) visual analogue scale (VAS) pain (rs = 0.28, p = 0.004) VAS global (rs = 0.22, p = 0.027), VAS fatigue (rs = 0.24, p = 0.013), joint index of 28 swollen joints (rs = 0.22, p = 0.027) and negative correlations with short‐form‐36 (SF‐36) physical functioning (rs = −0.18, p = 0.008), bodily pain (rs = −0.31, p < 0.001), general health (rs = −0.23, p = 0.019), vitality (rs = −0.31, p < 0.001), social function (rs = −0.24, p = 0.016) and role‐emotional (rs = −0.28, p = 0.005). Mean improvement for the most important leisure activity was 1.36, (p = 0.036, 95% confidence interval 0.10–2.62). Standardized response mean and effect size for the most important activity in PSLS was 1.05 and 0.72, respectively, and for HAQ 0.34 and 0.28, respectively.Conclusions: PSLS appears to be feasible, reliable, valid and responsive for measuring leisure activities in RA. It provides both an individual result which is useful in clinical work, and results at a group level. Copyright © 2009 John Wiley & Sons, Ltd.
Application of parameter differentiation for flow of a third grade fluid past an infinite porous plate
Authors: Sajid M. 
Published: February 2009

AbstractThis article investigates the analytic solution for the flow of a third grade fluid past an infinite porous plate. The method of parameter differentiation is used to linearized the governing flow equation. The solution of the obtained linear equation is developed by differential transform method in combination with the method of superposition. The obtained results are compared with existing results in the literature and an excellent agreement is found. This shows that the parameter differentiation is a powerful technique for solving nonlinear problems. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010
Isothermal crystallization of pure and glass fiber reinforced poly(phenylene sulfide) composites
Authors: Zhang Richao , Huang Yigang , Min Min , Gao Yong , Yu Xuejiang , Lu Ai , Lu Zhongyuan 
Published: February 2009

AbstractThe isothermal crystallization of poly(phenylene sulfide) (PPS) and its glass fiber (GF) reinforced composite has been investigated by differential scanning calorimetry (DSC) and polarized optical microscope (POM) equipped with a hot stage. During the isothermal crystallization process of PPS the Avrami exponent value decreases with time, indicating the change of crystallization mechanism and presence of mixed growth mechanism (bidimensional and three‐dimensional growth of crystals). The presence of GF greatly accelerates the bulk crystallization rate of PPS and changes the crystalline morphology of PPS from the spherulites to transcrystallization. And the reason for development of transcrystallization is considered to be relevant with the compatibility of the interface between GF and PPS. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Effect of 3‐propionylthio‐1‐propyltrimethoxylsilane on structure, mechanical, and dynamic mechanical properties of NR/silica composites
Authors: Peng Hualong , Liu Lan , Luo Yuanfang , Wang Xiaoping , Jia Demin 
Published: February 2009

AbstractBlocked mercaptosilane possessing two functionally active end groups can chemically react with both silica and rubber leading to significant improvement in silica‐filled vulcanizate products. The effect of the novel blocked mercaptosilane (3‐propionylthio‐1‐propyltrimethoxylsilane) (called hereafter PXT) on the structure, mechanical, and dynamic mechanical properties of NR/silica composite were studied. Equilibrium swelling test and scanning electron microscope (SEM) indicate that PXT is able to enhance the crosslinking density of natural rubber (NR)/silica composites and the dispersion of silica in matrix. Mechanical measurement of properties show that PXT can strengthen the reinforcement of silica for NR vulcanizate. In the presence of PXT, the resistance to flex cracking, abrasion and dynamic compression fatigue, and heat build‐up of NR/silica composites can be improved substantially. For the application of automotive tire, it also obtains high‐skid resistance and low‐rolling resistance simultaneously at 2 phr of the PXT concentration. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Anomalies, influencing factors, and guidelines for DMA testing of fiber reinforced composites
Authors: Swaminathan Gowthaman , Shivakumar Kunigal N. , Russell Larry C. 
Published: February 2009

AbstractThis study systematically assessed the measurement of dynamic properties of a range of fiber reinforced composite materials using dynamic mechanical analysis (DMA) instrument. The discrepancy in the moduli from DMA to ASTM tests was investigated. The study showed that proper specimen preparation, maintaining appropriate aspect ratio (span to thickness ratio) to reduce the transverse shear deformation, and sufficient loading are critical to measure correct properties from DMA test. The guidelines on aspect ratio and loading for plastics to high‐modulus carbon fiber composites are presented as a design chart and equations, respectively. The study also found that the glass transition temperature (Tg) was independent of specimen aspect ratio and Tg is lower for multidirectional composites when compared with its unidirectional composites. The particle interleaved T800H/3900‐2 composite showed two glass transition temperatures (140 and 198°C), the lower value is due to the effect of interleaving by thermoplastic particles, and the higher value is the Tg of its base matrix. This lowering of Tg would have significant effect on the application temperature of the material. This phenomenon was not observed here to fore in the literature. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Experimental failure analysis of bolted joints in moisture‐ and temperature‐induced composite laminates under preload
Authors: Gören Aytaç , Sayman Onur 
Published: February 2009

AbstractIn this study, an experimental investigation was carried out in a bolted glass fiber‐reinforced laminate under preload moments. The stacking sequence at the composite laminate was chosen as [90°/0°/45°/−30°]s. The preload moments were selected as 2, 4, and 6 Nm, in order to compare the influence of preload moments on failure modes and strengths. Some specimens were subjected to hot pure water at 70°C for 7 days. The bearing strength in this case was measured again under the same preload moments of 2, 4, and 6 Nm. It is found that the bearing strength of the specimen waited in hot water was 5.4% smaller than that of the specimen in dry condition. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Preparation, characterization, and thermal stability of novel PMMA/expandable graphite halogen‐free flame retardant composites
Authors: Chen Chia‐Hsun , Yen Wei‐Hsin , Kuan Hsu‐Chiang , Kuan Chen‐Feng , Chiang Chin‐Lung 
Published: February 2009

AbstractIn this investigation, expandable graphite was functionalized using a coupling agent to produce covalent bonds between the organic and inorganic phases, enhancing the thermal stability of the composites. The modified expandable graphite had an OEt function group that reacted with methyl methacrylate‐co‐3‐(trimethoxysilyl)propyl methacrylate. Fourier transform‐infrared spectrometry and X‐ray photoelectron spectra were adopted to characterize the grafting reaction between vinyltriethoxysilane and expandable graphite. It is affirmed that VTES has reacted with expandable graphite. The results of thermogravimetric analysis and thermogravimetric difference (TGΔ) reveal that functionalized expandable graphite can improve the thermal stability of composites. Scanning electron microscope was utilized to observe the morphology of the composites, and the behavior of expansion was discussed after the materials were burned. These results of X‐ray photoelectron spectra for char confirm that expandable graphite improves the degree of accumulation of char and that of the antioxidation of the composites. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Influence of carbon‐based nanofillers on the electrical and dielectric properties of ethylene vinyl acetate nanocomposites
Authors: George Jinu Jacob , Bhadra Sambhu , Bhowmick Anil K. 
Published: February 2009

AbstractA comparative study of ethylene vinyl acetate nanocomposites based on expanded graphite, multiwalled carbon nanotubes, and carbon nanofibers has been carried out to investigate the effect of different carbon nanofillers on the electrical properties of the corresponding composites. The composites were prepared by ultrasonic dispersion of fillers in ethylene vinyl acetate solution, followed by casting and compression molding. The dependence of AC conductivity and dielectric constant on the frequency and filler concentration was investigated. Carbon nanofibers provided maximum conductivity as well as lowest percolation threshold (8.2 vol%) compared to expanded graphite and multiwalled carbon nanotubes filled composites. The improvement in both electrical conductivity and dielectric constant was attributed to the high filler aspect ratio and the formation of conducting networks. The relationship of dielectric constant with filler volume fraction for all the composite systems is estimated using a power law. The pressure sensing capability of the composites at respective percolation thresholds was also compared. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Study on dispersion and intercalation of organoclay in PP and PP‐g‐MA matrices
Authors: Hedayati A. , Arefazar A. 
Published: February 2009

AbstractUnderstanding the complex mechanism of dispersion and intercalation of the clay tactoids can allow us to control the final morphology, homogeneity, and the macroscopic properties of clay nanocomposites. The objective of this work is a multiscale study of the dispersion state of PP/organoclay and PP‐g‐MA/organoclay composite. The microscopic investigation, WAXS diffractograms, rheological analysis, and mechanical properties were used to characterize the dispersion of organoclay in PP and PP‐g‐MA matrices during melt blending in two different shear rates. The morphological results show a system of aggregating intercalated clay particles which disperse by increasing mixing time with a strain‐controlled process and a very quick intercalation process in early mixing times for PP‐g‐MA/organoclay nanocomposite, while PP/organoclay samples only form microcomposites. The relative network modulus of these intercalated particles as a function of mixing time was obtained; and the tensile modulus of nanocomposite samples were compared with Halpin‐Tsai model prediction. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Flame resistance and foaming properties of NBR compounds with halogen‐free flame retardants
Authors: Moon SungCheal , Jo ByungWook , Farris Richard J. 
Published: February 2009

AbstractAcrylonitrile butadiene rubber (NBR) foams compounded with various halogen‐free flame retardants were prepared. The influence of nonhalogen flame retardants on the flame resistance and foaming properties of the NBR compounds were investigated. The foaming properties (expandability 980%–1050%, closed‐cell structure) of NBR compounds with expandable graphite (EG) and ammonium polyphosphate (APP) flame retardants were similar to the NBR base compounds which contained primarily aluminum hydroxide (ATH). The heat release capacity (HRC) ranged from 10 to 74 J/g‐K, the average heat release rate (A‐HRR) ranged from 8 to 60 kW/m2, and the total heat release (THR) ranged from 2.6 to 7.3 MJ/m2 for the nonhalogenated NBR foams with closed‐cell structure and were significantly decreased upon increasing the amounts of flame retardants. This reduction is attributed to the hard char formation and production of water from the interaction with ATH. The limiting oxygen index (LOI) and time to ignition (TTI) show opposite results. The smoke density (0.050–0.037) of the NBR foams with EG flame retardant was decreased when compared to the NBR foam (0.107). The EG flame retardant was more effective than the phosphorus/nitrogen flame retardants in reducing the HRR and smoke density. The use of both ATH and EG is very effective in improving flame resistance. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Strength improvement of iPP/MWCNT nanocomposites
Authors: Ritter U. , Scharff P. , Dmytrenko O.P. , Kulish N.P. , Prylutskyy Yu. I. , Grabovskiy Yu. E. , Belyi N.M. , Pinchuk T.N. , Alekseev A.N. , Sementsov Yu. I. , Gavrylyuk N.A. , Shlapatskaya V.V. 
Published: February 2009

AbstractThe mechanisms of microhardness increase in thermoplastic polypropylene/multi‐walled carbon nanotubes (MWCNT) nanocomposites during electron irradiation (Ee = 1.8 MeV) with different absorption doses are investigated. The crystal structure of the nanocomposites, Raman scattering, and microhardness in a MWCNT concentration range between 0.1 and 5.0 wt% is studied in detail. During irradiation, changes in the degree of crystallinity of the polymer matrix, lattice parameters of the topologically ordered phase, Raman scattering, and microhardness show a complex conjugation process between the composite components. Their interaction is accomplished as the result of the formation of new bonds, which appeared with the radiation damages. Furthermore, the crosslinking of the internal MWCNT layers also contributes to an increase in the strength properties of the polymer nanocomposites. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
The composition, morphology, and mechanical properties of ethylene propylene diene monomer‐encapsulated coal gangue powder/polypropylene composites
Authors: Liu Ying , Xie Bang‐Hu , Yang Wei , Yang Ming‐Bo 
Published: February 2009

AbstractThe ternary composites of coal gangue powder encapsulated by ethylene propylene diene monomer (EPDM) filled polypropylene (PP) were prepared to reduce the cost and control the microstructure aiming at high performance cost ratio materials. The result showed that EPDM can not only enhance the interaction between coal gangue powder and the matrix but also promote the dispersion of coal gangue powder. With the addition of coal gangue encapsulated by EPDM, the impact strength of composition dropped greatly, but it still kept about 11 kJ/m2 when the content of encapsulated coal gangue powder is more than 18 wt%. The tensile strength and fracture toughness (we) also dropped with the addition of encapsulated coal gangue powder, but only a small drop occurred when the content of encapsulated coal gangue powder is less than 18 wt% and great drop emerged when the content is larger than 18 wt%. Compared with coal gangue powder/PP binary composition, the ternary compositions involve higher content of coal gangue powder but present better properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Synthesis, thermal properties, and flame retardance of phosphorus‐containing epoxy‐silica hybrid resins
Authors: Yu Dan , Liu Weiqu , Liu Yunfeng 
Published: February 2009

AbstractA novel epoxy resin modifier, phosphorus‐containing epoxide siloxane (DPS) with cyclic phosphorus groups in the SiO network, was prepared from the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) with polyhedral‐oligomeric siloxanes, which was synthesized by the sol–gel reaction of 3‐glycidoxypropyltrimethoxysilane. DPS was confirmed by Fourier transform infrared and 29Si NMR measurement, and then was employed to modify epoxy resin at various ratios, with 4,4‐diaminodiphenyl‐methane as a curing agent. In order to make a comparison, DOPO‐containing epoxy resins were also cured under the same conditions. The resulting organic–inorganic hybrid epoxy resins modified with DPS exhibited a high glass transition temperature (Tg), a good thermal stability, and a high limited oxygen index. In addition, the tensile strength of cured products was also rather desirable. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers