bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upper limb kinematics and the role of the wrist during stone tool production
Authors: Williams E.M. , Gordon A.D. , Richmond B.G. 
Published: May 2010

AbstractPast studies have hypothesized that aspects of hominin upper limb morphology are linked to the ability to produce stone tools. However, we lack the data on upper limb motions needed to evaluate the biomechanical context of stone tool production. This study seeks to better understand the biomechanics of stone tool‐making by investigating upper limb joint kinematics, focusing on the role of the wrist joint, during simple flake production. We test the hypotheses, based on studies of other upper limb activities (e.g., throwing), that upper limb movements will occur in a proximal‐to‐distal sequence, culminating in rapid wrist flexion just prior to strike. Data were captured from four amateur knappers during simple flake production using a VICON motion analysis system (50 Hz). Results show that subjects utilized a proximal‐to‐distal joint sequence and disassociated the shoulder joint from the elbow and wrist joints, suggesting a shared strategy employed in other contexts (e.g., throwing) to increase target accuracy. The knapping strategy included moving the wrist into peak extension (subject peak grand mean = 47.3°) at the beginning of the downswing phase, which facilitated rapid wrist flexion and accelerated the hammerstone toward the nodule. This sequence resulted in the production of significantly more mechanical work, and therefore greater strike forces, than would otherwise be produced. Together these results represent a strategy for increasing knapping efficiency in Homo sapiens and point to aspects of skeletal anatomy that might be examined to assess potential knapping ability and efficiency in fossil hominin taxa. Am J Phys Anthropol 143:134‐145, 2010. © 2010 Wiley‐Liss, Inc.
Effective reinforcement of carbon nanotubes in polypropylene matrices
Authors: Deng H. , Bilotti E. , Zhang R. , Peijs T. 
Published: May 2010

AbstractThis study describes an attempt to mechanically reinforce polypropylene (PP) using multi‐wall carbon nanotubes (MWNTs) through a melt compounding process followed by hot‐pressing and solid state drawing. The effect of a high density polyethylene (HDPE) coating on MWNTs and melt flow index (MFI) of PP on the dispersion of MWNTs and composite properties are studied by means of mechanical tests, transmission electron microscopy (TEM), scanning electron microscope (SEM), differential scanning calorimetry (DSC), and wide angle x‐ray diffraction (WAXD). Highly orientated composite tapes are prepared to fully utilize the properties of MWNTs in uniaxial direction. Highly aligned MWNTs are shown by SEM, while highly oriented polymer chains are characterized by WAXD. Composite theory is used to analysis the results and indicate that effective reinforcement of PP by MWNTs is highest at relatively low filler content and draw ratios. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of filler loading on the mechanical properties of crosslinked 1,2,3‐triazole polymers
Authors: Katritzky Alan R. , Sakhuja Rajeev , Huang Longchuan , Gyanda Reena , Wang Ling , Jackson David Carnaby , Ciaramitaro David A. , Bedford Clifford D. , Duran Randolph S. 
Published: May 2010

AbstractThe effect of filler loading on the mechanical properties of crosslinked triazole polymers obtained by polymerization of E300 dipropiolate (1) with diazide (2) obtained from tetraethylene glycol using tetraacetylene functionalized crosslinker (3) was studied systematically. Aluminum (10–14 μm) was used as the primary filler during the formulations; the effect of secondary fillers such as aluminum (<75 μm), NaCl (45–50 and 83–105 μm) was studied with the increase in the total filler loading. The modulus of the aluminum‐filled crosslinked triazole polymers increases with the increase in the filler content while using either particle sized aluminum powder. The use of Al (particle size <75 μm) and NaCl (particle size 45–50 μm and 83–105 μm) as secondary or additional fillers while using aluminum (10–14 μm) as the main filler, has a diminishing effect on the modulus and strain of the crosslinked triazole polymers. Triazole polymers described herein have the ability to wet and adhere to large quantities of these inorganic salts and thus maintain mechanical properties of the composite comparable to typical polyurethane elastomeric matrices, regardless of the chemistry of the particulate filler, which imparts an important and necessary binder characteristic for energetic composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of polymer/multiwall carbon nanotube/nanoparticle nanocomposites and preparation of their metal complexes
Authors: Golikand Ahmad Nozad , Didehban Khadijeh 
Published: May 2010

AbstractCarbon nanotube‐polymer nanocomposites were synthesized and characterized successfully. In this work, multiwall carbon nanotubes (MWCNT) were opened using HNO3/H2SO4 mixture and filled by metal nanoparticles such as silver nanoparticles through wet‐chemistry method. The oxidized MWCNT were reacted subsequently with thionyl chloride, 1,6‐diaminohexane, producing MWNT‐amine functionalized. Then the MWCNT containing metal nanoparticles were used as a monomer with different weight percentages in melt polymerization with An and CNCl separately. Furthermore, the polyamide and polytriazine modified MWCNT were used for the preparation of metal ion complexes such as Fe+2 and La+3. The structures and properties of nanocomposites were evaluated by TEM, DSC, TGA, and FT‐IR methods. The chelating behavior and sorption capacities of prepared nanocomposites were carried out by using some metal ions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structure and gas permeation properties of asymmetric polyimide membranes made by dry–wet phase inversion: Influence of the polyimide molecular weight
Authors: Seki Naoko , Nagaoka Shoji , Kawakami Hiroyoshi 
Published: May 2010

AbstractIn this article, we report the influence of the polyimide molecular weight (1.2 × 105, 2.6 × 105, and 4.1 × 105) on the structure and the gas permeation properties of asymmetric polyimide membranes made by the dry–wet phase‐inversion process. The apparent skin layer thickness of the asymmetric membrane increased with increasing molecular weight, and the thicknesses of the membranes prepared from the three polyimides with a casting polymer solution containing 8.0 wt % butanol were 132, 350, and 739 nm, respectively. That is, the gas permeance in the asymmetric membranes increased with decreasing molecular weight. In contrast, the gas selectivity of the asymmetric membranes did not depend on the skin layer thickness. The solvent evaporation in the dry phase‐inversion process and the nonsolvent diffusion in the dry process were important factors that determined the formation of the asymmetric membrane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Studies on sorption isotherm models of ion exchange modified acrylic fibers
Authors: Zargaran Mojdeh , Shoushtari Ahmad M. , Abdouss Majid 
Published: May 2010

AbstractThe sorption behavior, favorability, shape and thermodynamic parameters of Cu(II), Ni(II), Pb(II), and Fe(III) ions sorption onto the ion exchage acrylic fiber were studied by applying Langmuir, Freundlich, Dubinin‐Radushkevich and Redlich–Peterson models. Analytical studies from sorption isotherms proved that sorption process follows mono layer adsorption mechanism. Gibbs free energy was spontaneous for all interactions. The adsorption processes all exhibited endothermic enthalpy values and were accompanied by increasing in entropy. The activation energies for the sorption of metal ions on aminated acrylic fiber were at the same order of magnitude as the activation energy of ion exchange. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of poly(4‐diphenylaminostyrene)‐Poly(9‐vinylanthracene) binary block copolymer
Authors: Natori Itaru , Natori Shizue , Sekikawa Hiroyuki , Takahashi Tomoyuki , Sato Hisaya 
Published: May 2010

AbstractBlock copolymerization of plural types of monomers offers a new opportunity for the preparation of a variety of multifunctional polymers. Poly(4‐diphenylaminostyrene) (PDAS)‐poly(9‐vinylanthracene) (PVAN) binary block copolymer (PDAS‐PVAN) was synthesized by (living) anionic polymerization using the benzyllithium/N,N,N′,N′‐tetramethylethylenediamine system. The photoluminescence emission of PDAS‐PVAN was enhanced by the fluorescence resonance energy transfer from PDAS block to PVAN block in PDAS‐PVAN. The hole drift mobility of the copolymer was controllable by the amount of triphenylamino groups in the polymer chain. The optical and electrical properties of PDAS‐PVAN were adjustable through the polymer chain structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and properties of polymer from bis‐3,4‐ethylenedioxythiophene substituted acenaphthenequinoxaline
Authors: Matsidik Rukiya , Mamtimin Xirali , Mi Hong Yu , Nurulla Ismayil 
Published: May 2010

AbstractA new electrochoromic polymer poly(8,11‐bis(3,4‐ethylenedioxy thiophen‐2‐yl)acenaphtho[1,2‐b]‐quinoxaline) (PBEAQ) was synthesized by electrochemical polymerization of the corresponding monomer (BEAQ) in a 0.1 M tetraethylammonium tetrafluoroborate (TEABF4) dichloromethane–acetonitrile (2 : 1, v : v) solution. The monomer and polymer were characterized by elemental analysis, 1H‐NMR, IR, and UV‐vis spectroscopy. The electrochemical and optical properties of polymer were investigated by cyclic voltammetry and UV‐vis spectroscopy. Cyclic voltammetry and spectroelectrochemistry studies demonstrated that the polymer can be reversibly reduced and oxidized (both n‐ and p‐doped) between −2 V and +1.5 V vs. Ag/Ag+. The polymer had a transmissive light blue color in the oxidized state and reddish color in the reduced state. Undoped polymer shows UV‐vis absorption peaks at 615 nm in solution, 650 nm in solid state, and has an optical band gap of 1.5 eV. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Catalytic oxidation of organic substrates using a reusable polystyrene‐anchored orthometallated palladium(II) complex
Authors: Islam Manirul , Mondal Paramita , Roy Anupam Singha , Tuhina K. 
Published: May 2010

AbstractA new heterogeneous secondary amine Pd(II) complex anchored to macroporous polystyrene beads, P‐[Pd2(seam)2(OAc)2] (seam = secondary amine), was synthesized by reacting polymer‐anchored secondary amine with palladium acetate in acetic acid medium. The structure of this immobilized complex has been established on the basis of scanning electron microscope, thermogravimetric analysis, elemental analysis, atomic absorption spectroscopy, and spectrometric methods like diffuse reflectance spectra of solid and Fourier transform infrared spectroscopy. The catalytic activity of the Pd‐complex was investigated toward the oxidation of various olefins and alcohols in presence of tert‐butylhydroperoxide as an oxidant. The effects of various parameters such as solvent, oxidant, reaction time, reaction temperature, amount of catalyst, and substrates‐to‐oxidant ratio have been studied. The catalytic results reveal that the present polymer‐anchored Pd(II) complex can be recycled more than seven times without much loss in the catalytic activity. Comparative studies have been done with the corresponding unsupported metal complex. The polymer‐anchored catalyst was found to be superior to its homogeneous counterpart in activity, product selectivity, stability, and reusability © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on the synthesis, structure, and properties of polydimethylsiloxane‐acrylate/organophilic montmorillonite nanocomposite emulsions
Authors: Li Hong‐Qiang , Zeng Xing‐Rong , Deng Hui‐Ping 
Published: May 2010

AbstractPolydimethylsiloxane‐acrylate/organophilic montmorillonite (PDMS‐ACR/OMMT) nanocomposite emulsions were prepared by the copolymerization between ACR and PDMS/OMMT seeding emulsion, which was prepared beforehand by ring‐opening in situ polymerization of octamethyl cyclotetrasiloxane (D4) intercalated into the interlayer of OMMT modified with dodecylbenzene sulfonate acid (DBSA). OMMT, PDMS/OMMT seeding emulsion, and PDMS‐ACR/OMMT nanocomposite emulsions were characterized with X‐ray diffraction, FTIR, laser particle size analysis, SEM, and TG; the physical properties of the of PDMS‐ACR/OMMT latex films were also characterized including adherence, impact property, bend property, hardness, and water resistance. The results showed that DBSA was intercalated into the interlayer of montmorillonite, and ring‐opening in situ polymerization of D4 could be carried out favorably in OMMT interlayer. The onset weight‐loss temperature of PDMS‐ACR/OMMT latex films was higher than that of polyacrylate latex film by 44°C. When the addition of the amount of OMMT was 2 wt % in PDMS‐ACR/OMMT emulsions, OMMT had been peeled into layered structure and dispersed in the continuous polymer phase, the shape of OMMT was regular and its size was uniform, the physical properties of the latex films were improved obviously. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of elastomer‐based nanocomposite gels using an unique latex blending technique
Authors: Mitra Suman , Chattopadhyay Santanu , Bhowmick Anil K. 
Published: May 2010

AbstractNanocomposite (NC) gels based on natural rubber (NR) and styrene butadiene rubber (SBR) were prepared by using a unique latex blending technique. These NC gels were prepared by first blending the water swollen unmodified montmorillonite clay (Na+‐MMT) suspension into the respective latices followed by prevulcanization to generate crosslinked nanogels. Use of water assisted fully delaminated Na+‐MMT suspension resulted in predominantly exfoliated morphology in the NC gels, as revealed by X‐ray diffraction study and transmission electron microscopy. Addition of Na+‐MMT significantly improved various physical, mechanical and thermal properties of these NC gels. For example, 6 phr of Na+‐MMT loaded NR based NC gels registered 54% and 200% increase in tensile strength and Young's modulus, respectively, compared to the unfilled NR gels. SBR based NC gels also showed similar level of improvement in mechanical properties. Mechanical properties of NC gels prepared using this route were also compared with the NC gels prepared by co‐coagulation and conventional curing technique and found to be superior. In the case of dynamic mechanical properties, NC gels showed higher glass transition temperatures along with a concomitant increase in storage moduli, compared to the unfilled gels. These Na+‐MMT reinforced NC gels also exhibited markedly improved thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Thermally induced solid‐state synthesis of fluorine‐containing poly(ether oxadiazole)
Authors: Maruyama Yuka , Maeda Yukihiko , Wakabayashi Kanji , Yamazaki Shinichi , Kimura Kunio 
Published: May 2010

AbstractSynthesis of poly[oxy‐(2,3,5,6‐tetrafluoro‐1,4‐phenylene)‐(1,3,4‐oxadiazol‐2‐yl)‐1,4‐phenylene] (F‐PEOz) was examined by nucleophilic aromatic substitution reaction of 2‐(4‐hydroxyphenyl)‐5‐pentafluorophenyl‐1,3,4‐oxadiazole (HPOz). Only low molecular weight F‐PEOz or crosslinked insoluble polymers were obtained by the solution polymerization with bases. In contrast, thermally induced solid‐state polymerization of HPOz potassium salts at 180°C for 1 h gave fully soluble F‐PEOz with the yield of 84% and its reduced viscosity was 0.66 dL g−1. The longer polymerization time gave insoluble polymers due to the crosslinking reaction even in solid state. The solid‐state polymerization did not undergo topochemically and it proceeded in an amorphous state. The crosslinking reaction was slightly inhibited by the solid‐state polymerization. F‐PEOz exhibited excellent solubility, high Tg of 246°C and good thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of novel highly branched block copoly(urethane‐imide)s based on pentaerythritol, different diisocyanate and aromatic dianhydride
Authors: Chen Wenqiu , Chen Chuan , Yan Wei , Yi Changfeng , Wu Shuilin , Yeung Kelvin W. K. , Xu Zushun 
Published: May 2010

AbstractIn this work, we for the first time prepared a series of novel highly branched block copoly (urethane‐imide)s (CoPUIs) successfully by the condensation polymerization of star‐like prepolymers and dianhydrides, (including pyromellitic dianhydride (PMDA), 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride, and 4,4′‐oxydiphthalic anhydride) and the star‐like prepolymers were synthesized from pentaerythritol (PAT) and toluene‐2,4‐diisocyanate (TDI) or isophorone diisocyanate. Our results revealed that it took about 40 min to complete the prepolymerization of PAT and TDI at 40°C. In addition, the imidization of the prepolymer and PMDA was successfully carried out at 120°C for 2 h. The X‐ray diffractometer patterns exhibited that the resulting CoPUIs presented heterogenous structure with the d‐spacing around 0.40 nm. Differential scanning calorimeter curves showed that the Tg of these CoPUIs ranged from 214 to 229°C in N2 atmosphere. Thermogravimetric analyzer curves indicated that these synthesized CoPUIs had obviously two steps of weight loss in N2 atmosphere due to the used monomers which decomposed at 230–235°C and 602–644°C, respectively. The solubility testing results showed that the highly branched block CoPUIs had desirable solubility in several strong polar aprotic solvents and exhibited a strong resistance to dilute acid corrosion. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of styrene‐maleic anhydride as a reactive compatibilizer on the mechanical properties and flammability of intumescent flame retardant polystyrene
Authors: Chen Yajun , Guo Zhenghong , Fang Zhengping 
Published: May 2010

AbstractPolystyrene (PS) was flame retarded with a polymeric intumescent flame retardant, poly(diaminodiphenyl methane spirocyclic pentaerythritol bisphosphonate) (PDSPB), and in situ compatibilized with styrene‐maleic anhydride (SMA) copolymer. Compatibilization reaction was verified by IR spectroscopy and gel content measurement. Electron microscopy images showed that compatibilization could considerably reduce the size of the flame retardant domains and improve the interfacial adhesion between PS and PDSPB. With the same PDSPB loading (20 wt %), addition of 5, 10, and 20 wt % SMA increased the impact strength of the flame retarded PS by about 29, 103, and 201%, respectively. Compared with PS/PDSPB sample, addition of 5 wt % of SMA improved the limiting oxygen index from 23.8 to 24.2 and reduced the peak heat release rate (PHRR) of the blend by 18.3%. However, further increment of SMA content deteriorated the flame retardancy of the blend. It was found that the NH2 groups changed into more stable imide groups at high temperature, causing the absence of gas source. Therefore, the intumescent char could not be formed during combustion process, which was the main reason for the deteriorate effect of flame retardancy at high SMA loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Timing of Ectocranial Suture Activity in Pan troglodytes as Related to Cranial Volume and Dental Eruption
Authors: Cray James , Mooney Mark P. , Siegel Michael I. 
Published: May 2010

AbstractResearch has shown that Pan and Homo have similar ectocranial suture synostosis patterns possibly because of their phylogenetic relationship. However, unlike human data, it is unclear if the ontogeny of suture activity for Pan exhibits a relationship with the expanding neurocranium or the masticatory apparatus. These relationships were assessed by examining the associations between ectocranial suture status and morphology and cranial volume (as a proxy for neurocranial expansion) and dental development (as an indicator of adulthood and proxy for masticatory influence) in a large sample of Pan troglodytes skulls. One hundred and fifty‐five P. troglodytes dry skulls were examined, and data were collected on ectocranial suture closure status, cranial volume, and dental eruption status. Regression models were calculated for suture status by cranial volumes, and Kendall's tau (a nonparametric measure of association) was calculated for suture status by dental eruption status. Results suggest that suture synostosis activity in P. troglodytes exhibits a period of stasis after neurocranial expansion cessation and does not have a strong relationship with brain development (r2 ranged from 0.09 to 0.28), as similarly seen in Homo. Instead, suture synostosis has a stronger relationship with dental development (τ ranged from 0.59 to 0.72), where most osseous activity occurs after full adult dental eruption. This suggests that masticatory forces may influence both ectocranial suture morphology and synostosis more than brain expansion does in Pan, as also similarly noted in Homo. Anat Rec 293:1289–1296, 2010. © 2010 Wiley‐Liss, Inc.
Topological centrality and its e‐Science applications
Authors: Zhuge Hai , Zhang Junsheng 
Published: May 2010

AbstractNetwork structure analysis plays an important role in characterizing complex systems. Different from previous network centrality measures, this article proposes the topological centrality measure reflecting the topological positions of nodes and edges as well as influence between nodes and edges in general network. Experiments on different networks show distinguished features of the topological centrality by comparing with the degree centrality, closeness centrality, betweenness centrality, information centrality, and PageRank. The topological centrality measure is then applied to discover communities and to construct the backbone network. Its characteristics and significance is further shown in e‐Science applications.
Reactions of 7,8‐Dithiabicyclo[4.2.1]nona‐2,4‐diene 7‐exo‐Oxide with Dodecacarbonyl Triiron Fe3(CO)12: A Novel Type of Sulfenato Thiolato Diiron Hexacarbonyl Complexes
Authors: Windhager Jochen , Apfel Ulf‐Peter , Yoshino Tomoharu , Nakata Norio , Görls Helmar , Rudolph Manfred , Ishii Akihiko , Weigand Wolfgang 
Published: May 2010

AbstractThe reaction of Fe3(CO)12 (13) with 7,8‐dithiabicyclo[4.2.1]nona‐2,4‐diene 7‐exo‐oxide (12) yields the sulfenato‐thiolato complex 14, which is used as starting material for further reactions. The disulfenato complex 17 is obtained by using one equivalent of dimethyldioxirane (DMD), and the monoepoxide 18 is prepared by the oxidation of 14 with an excess of DMD. Complex 14 can be converted to the monophosphine complexes 19a and 19b by subsequent substitution of one CO ligand using trimethylaminoxide Me3NO and triphenylphosphine PPh3. Additional substitution reactions are done with 17 by using acetonitrile as a ligand to form 20a and 20b. In the electrochemical part of the paper, the reactions of the reduced iron species 14, 15, 17, and 19a are studied.