bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ritual Patterns in the Deposits of Fauna Associated with Iberian Burials: The Necropolis of El Poblado During the Fourth to Second Centuries bc (Archaeological Complex of Coimbra del Barranco Ancho, Murcia)
Authors: Albizuri S. , SubirÀ M. E. , Ruiz J. 
Published: September 2012

AbstractThe study of grave goods, including animal deposits, offers a deeper understanding of social issues. This paper presents the results of the analysis of human and animal bone samples from the Iberian necropolis of El Poblado, Murcia. The examination focusses on 18 deposits of ovicaprids radii and ulnae, mostly of the left side, that were derived from 14 cremation tombs of the 74 studied. By considering the human and animal remains together, it is possible to highlight differences in the rituals of certain graves and variations in animal symbolism related to human sex and age. This provides a new understanding of the social and cultural differentiation that existed in the Iberian communities of this period. Copyright © 2012 John Wiley & Sons, Ltd.
Transport studies of peanut shell powder reinforced natural rubber composites in aromatic solvents
Authors: Sareena C. , Ramesan M.T. , Purushothaman E. 
Published: September 2012

AbstractThis article investigates the transport behavior of three aromatic organic solvents, viz. benzene, toluene, and xylene in natural rubber (NR) composite membranes containing peanut shell powder (PSP) as filler at different temperatures by conventional weight‐gain experiments. PSP used in compounding the NR was processed in two particle sizes. The solvent swelling characteristics of NR composites containing both untreated and alkali‐treated fillers were investigated. The computed sorption characteristics were discussed in terms of PSP content, particle size, nature of solvent, and temperature. All the NR‐PSP composites were found to decrease with the uptake of aromatic solvents than NR, but the effect was more significant in the case of alkali‐treated PSP composites. Furthermore, the uptake of solvent decreased with decrease in penetrant size. The estimated Arrhenius activation energies (ED) for the processes of sorption, diffusion, and permeation showed that ED was generally highest in xylene at the filler contents investigated. The thermodynamic parameters of the sorption process were also evaluated. The relationship between the transport behavior and the morphology of the system was examined. The mechanism of diffusion is found to be close to Fickian trend in toluene and xylene and Fickian trend in benzene. Comparison between theoretical and experimental diffusion results was made to understand the mechanism of diffusion. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Synthesis and characterization of high performance, transparent interpenetrating polymer networks with polyurethane and poly(methyl methacrylate)
Authors: Bird S.A. , Clary D. , Jajam K.C. , Tippur H.V. , Auad M.L. 
Published: September 2012

AbstractTransparent, interpenetrating polymer network (IPN) materials were synthesized using polyurethane (PU) and poly(methyl methacrylate) (PMMA). PMMA contributed to the transparency and rigidity necessary for use in impact‐resistant applications, whereas PU contributed to toughness. Several factors affecting the physical properties, such as the ratio of PU to PMMA, curing profile, inclusion of different isocyanates for the PU phase, and use of an inhibitor in the PMMA phase, were investigated. Full‐IPNs were synthesized so that the two polymer networks would remain entangled with one another, and domain sizes of each system were reduced, mitigating phase separation. Both simultaneous IPNs, polymerization of monomers occurring at the same time, and sequential IPNs, polymerization of monomers occurring at different temperatures, were synthesized for studying the reaction kinetics and final morphologies. The phase morphology and the final thermal and mechanical properties of the IPNs prepared were evaluated. Findings suggest that samples containing ∼80 wt% PMMA, 1,6‐diisocyanatohexane 99+% (DCH), and an inhibitor with the MMA monomer created favorable results in the thermo‐mechanical and optical properties. POLYM. ENG. SCI. 2013. © 2012 Society of Plastics Engineers
Grafting of water‐soluble sulfonated monomers onto functionalized fumed silica nanoparticles via surface‐initiated redox polymerization in aqueous medium
Authors: Abdollahi Mahdi , Rouhani Morteza , Hemmati Mahmoud , Salarizadeh Parisa 
Published: September 2012

AbstractSulfonated polymer/fumed silica hybrid nanoparticles were prepared via surface‐initiated free radical polymerization of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (PAMPS‐g‐FSN), styrene sulfonic acid sodium salt (PSSA‐g‐FSN) and vinyl sulfonic acid sodium salt (PVSA‐g‐FSN) from the surface of aminopropyl‐functionalized fumed silica nanoparticles (AFSNs) dispersed in aqueous medium. Cerium(IV) ammonium nitrate/nitric acid and sodium dodecyl sulfate were used as redox initiator and stabilizer respectively. AFSNs were prepared by covalently attaching 3‐aminopropyltriethoxysilane onto the surface of fumed silica nanoparticles. Sulfonated monomers (AMPS, SSA or VSA) were then grafted onto the AFSNs ultrasonically dispersed in water via redox initiation at 40 °C. Structure, thermal properties, particle size and morphology of the AFSNs and PAMPS‐g‐FSN, PSSA‐g‐FSN and PVSA‐g‐FSN hybrid nanoparticles were characterized by Fourier transform infrared spectroscopy, TGA, SEM, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results indicated that the sulfonated monomers were successfully grafted onto the fumed silica nanoparticles. Grafting amounts of the sulfonated polymers onto the fumed silica nanoparticle surface were estimated from TGA thermograms to be 59%, 13% and 29% for the PAMPS, PSSA and PVSA, respectively. From SEM, TEM and DLS analysis, polymer‐grafted fumed silica nanoparticles with an average diameter smaller than 70 nm and a (semi‐) spherical shape were observed. A significant bimodal particle size distribution was observed only for the PAMPS‐g‐FSN with average diameters of 39.6 nm (84.1% per number) and 106 nm (15.9% per number). The hydrophilic sulfonated polymer/grafted fumed silica obtained from the redox graft polymerization gave a stable colloidal dispersion in acidic aqueous medium. Copyright © 2012 Society of Chemical Industry
Enhanced solubility of novel poly(benzoxazole)s with a soft linkage and a rigid pendant group
Authors: Fu Qian , Zhuang Qixin , Liu Xiaoyun , Han Zhewen 
Published: September 2012

AbstractAromatic poly(benzoxazole)s are a class of rigid‐rod conjugated polymers. However, their poor solubility in organic solvents limits potential applications. Thus, a good method that can address this dilemma is needed, given that existing methods involve models with either poor solubility but good thermal stability or good solubility but poor thermal stability. In this paper we report a novel aromatic poly(benzoxazole) with a soft linkage and a rigid pendant group. Structural characterizations of the polymers via Fourier transform infrared and proton nuclear magnetic resonance spectroscopy reveal the formation of a benzoxazole ring and an imide ring. The introduction of rigid pendant groups improved the solubility and enhanced the thermal stability of the polymer, which was impaired by the incorporation of the soft linkage. Most of these polymers are soluble at room temperature or when heated in dimethyl sulfoxide, N,N‐dimethylformamide or N,N‐dimethylacetamide. Some polymers can even be dissolved in m‐cresol and tetrahydrofuran. A 10% weight loss in these polymers was observed at temperatures over 410 °C. Moreover, the incorporation of the imide pendant group increased the conjugation length of the polymer structural unit and accelerated electron delocalization. Copyright © 2012 Society of Chemical Industry
Modeling of concentrating photovoltaic and thermal systems
Authors: Helmers Henning , Bett Andreas W. , Parisi Jürgen , Agert Carsten 
Published: September 2012

ABSTRACTAn energy balance model for concentrating photovoltaic and thermal (CPVT) systems is presented. In the model, the CPVT system and its environment are represented using a set of input parameters. The main outputs of the model are the system's electrical and thermal efficiencies. The model accounts for optical losses. Thermal losses are derived from a thermal network model of the hybrid receiver. The solar cell performance is modeled as a function of the temperature and the irradiance. The robustness of the model is demonstrated by a sensitivity analysis of all input parameters.The influence of the operating temperature on the electrical and thermal performances and the overall efficiency of the CPVT system are discussed. The limiting cases of maximum electrical and thermal power outputs are presented. Further, the influence of the concentration ratio on the electrical and thermal performance and on the partitioning of these two power outputs is analyzed in detail. It is shown that high concentration reduces the thermal losses considerably and increases the electrical efficiency. At concentration ratios above 300, the system operates with an overall efficiency of 75% at temperatures up to 160 °C. Copyright © 2012 John Wiley & Sons, Ltd.
Two modes of asymmetric polymerization of phenylacetylenes having an L‐amino alcohol residue and two hydroxy groups
Authors: Jia Hongge , Li Jun , Zang Yu , Aoki Toshiki , Teraguchi Masahiro , Kaneko Takashi 
Published: September 2012

AbstractFour novel chiral phenylacetylenes having an L‐amino alcohol residue and two hydroxymethyl groups were synthesized and polymerized by an achiral catalyst ((nbd)Rh+[η6‐(C6H5)B−(C6H5)3]) or a chiral catalytic system ([Rh(nbd)Cl]2/(S)‐ or (R)‐phenylethylamine ((S)‐ or (R)‐PEA)). The two resulting polymers having an L‐valinol or L‐phenylalaninol residue showed Cotton effects at wavelengths around 430 nm. This observation indicated that they had an excess of one‐handed helical backbones. Positive and negative Cotton effects were observed only for the polymers having an L‐valinol residue produced by using (R)‐ and (S)‐PEA as a cocatalyst, respectively, although the monomer had the same chirality. Even when the achiral catalyst was used, the two resulting polymers having an L‐valinol or L‐phenylalaninol residue showed Cotton effects despite the long distance between the chiral groups and the main chain. We have found the first example of a new type of chiral monomer, that is, a chiral phenylacetylene monomer having an L‐amino alcohol residue and two hydroxy groups that was suitable for both modes of asymmetric polymerization, that is, the helix‐sense‐selective polymerization (HSSP) with the chiral catalytic system and the asymmetric‐induced polymerization (AIP) with the achiral catalyst. The other two monomers having L‐alaninol and L‐tyrosinol were found to be unsuitable to neither HSSP nor AIP because of their polymers' low solubility. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Polymer BHJ solar cell performance tuning by C60 fullerene derivative alkyl side‐chain length
Authors: Kästner Christian , Ulbricht Christoph , Egbe Daniel A. M. , Hoppe Harald 
Published: September 2012

AbstractA systematic study on the influence of the alkyl side‐chain length of C60 based fullerene derivatives in polymer solar cells based on an anthracene‐containing poly(p‐phenylene‐ethynylene)‐alt‐poly(p‐phenylene‐vinylene) (PPE‐PPV) copolymer (AnE‐PV) is reported. It is shown that the alkyl side‐chain length of the fullerene derivative strongly correlates with the individual photovoltaic parameters. The most pronounced dependence on the side‐chain length is found for the fill factor, spanning the range between 50–72%, which dominantly controls in combination with the short‐circuit current the power conversion efficiency. The maximum performance of 4.8% was found for an ethyl terminated side‐chain, whereas larger alkyl groups resulted in a gradually decreasing power conversion efficiency. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Nanoindentation, nanoscratch, and nanotensile testing of poly(vinylidene fluoride)‐polyhedral oligomeric silsesquioxane nanocomposites
Authors: Zeng Fanlin , Liu Yizhi , Sun Yi , Hu Enlai , Zhou Yu 
Published: September 2012

AbstractNanocomposites composed of a poly(vinylidene fluoride) (PVDF) matrix and 0, 3, 5, and 8 wt % fluoropropyl polyhedral oligomeric silsesquioxane (FP‐POSS) were prepared by using the solvent evaporation method. The morphology and the crystalline phase of the nanocomposites were investigated by digital microscopy, scanning probe microscopy, X‐ray diffractometer, and Fourier transform infrared spectroscopy. FP‐POSS acted as nucleating agent in PVDF matrix. A small content of FP‐POSS resulted in an incomplete nucleation of PVDF and generated bigger spherical particles, whereas higher contents led to a complete nucleation and formed more separate and less‐crosslinked particles. Nanoindentation, nanoscratch, and nanotensile tests were carried out to study the influence of different contents of FP‐POSS on the key static and dynamic mechanical properties of different systems. The nanocomposite with 3 wt % FP‐POSS was found to possess enhanced elastic properties and hardness. However, with the increase of the FP‐POSS content, the elastic modulus and hardness were found to decrease, and the improvement on stiffness was negative at contents of 5 and 8 wt %. Compared with neat PVDF, the scratch resistance of the PVDF/FP‐POSS nanocomposites was decreased due to a rougher surface derived from the bigger spherulites. Nanotensile testing results showed both the stiffness and toughness of PVDF‐FP3% were enhanced and further additions of FP‐POSS brought dramatic enhancements in toughness while associated with a decline in stiffness. Dynamical mechanical properties indicated the viscosity of the nanocomposites increased with the increasing FP‐POSS contents. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Physical aging and deformation kinetics of polycarbonate
Authors: Senden Dirk J. A. , van Dommelen Johannes A. W. , Govaert L. E. 
Published: September 2012

AbstractConsidering the current view that physical aging of glasses results in an increase of activation barriers to plastic deformation, it is surprising that, until now, no influence of physical aging was observed experimentally on the temperature dependence of plastic deformation in polymeric glasses. This study evaluates why such an influence has not been found, and it is shown that detailed analysis of a set of uniaxial compression data on polycarbonate (PC) at different strain rates and temperatures leads to the conclusion that a significant influence indeed exists. As a consequence, the Eyring activation energy depends on the aging history of the material. These experimental observations are rationalized in terms of a simple physical interpretation of the aging phenomenon. The article also contains a discussion of the apparent deaging of amorphous polymers induced by large‐strain plastic deformation. This discussion is of key importance here, because this study compares yield stresses of aged PC with those of mechanically deaged, or rejuvenated, PC. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Decoupling of reactions in reactive polymer blending for nanoscale morphology control
Authors: Bhadane Prashant A. , Cheng John , Ellul Maria D. , Favis Basil D. 
Published: September 2012

AbstractIn this study, a dynamic vulcanized alloy of brominated poly(isobutylene‐co‐p‐methylstyrene) (BIMSM) and polyamide (PA) has been investigated. An interfacial reaction between BIMSM and PA and a crosslinking reaction between BIMSM molecules is carried out simultaneously during melt blending. To form a vulcanized, nanoscale elastomer dispersion, the timing of these reactions is key and the interfacial reaction should be well advanced before the vulcanization reaction initiates. At a blending temperature of 205 °C, independent of the processing conditions, it is found that the interfacial reaction dominates the phase morphology development. Increasing the melt processing temperature, however, begins to favor the vulcanization reaction over the interfacial reaction. In nonplasticized blends, it is found that increasing the temperature above 235 °C increases the speed of the vulcanization reaction to a level that it dominates the phase morphology development. As a result, the phase size increases by 2.5‐fold because the system is vulcanized before the interfacial modification step is complete. Adding plasticizer to the PA matrix increases the overall phase size, but shows a similar behavior with increase in temperature from 205 to 255 °C. The critical temperature where the vulcanization reaction starts dominating phase morphology in the plasticized systems is at 225 °C. Once the processing temperature is above the critical temperature, it is found that the mixing sequence can be used to time and decouple the reactions. The work demonstrates that a close control over the temperature and processing conditions can be used to decouple the interfacial and vulcanization reactions resulting in vulcanized, nanoscale dispersions for the BIMSM and PA system. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Study of Sn migration during relaxation of Ge1‐xSnx layers using atom probe tomography
Authors: Kumar Arul , Gencarelli Federica , Kambham Ajay Kumar , Gilbert Matthieu , Vincent Benjamin , Vandervorst Wilfried 
Published: September 2012

AbstractGe1‐xSnx is receiving a growing interest in the semiconductor community as it is predicted that at ∼10% Sn concentration, unstrained Ge1‐xSnx will exhibit a direct band gap leading to potentially important Opto‐electronic applications. In strained Ge1‐xSnx the expected concentration of Sn for this crossover from an indirect towards a direct bandgap is even lower. Moreover Sn has a ∼13% lattice mismatch with Ge opening up possibilities for strain engineering in high mobility CMOS devices based on Ge. Although Ge1‐xSnxlayers have been grown using various methods like molecular beam epitaxy, CVD growth etc. with Sn concentrations as high as 10%, one is faced with the problem of limited Sn‐solubility in Ge and hence the corresponding limits beyond which the layer starts to relax. Understanding relaxation mechanisms and kinetics of these layers requires insight at the atomic scale of Sn‐migration processes for which Atom Probe Tomography (APT) is a powerful tool. In this paper we use APT for characterizing Ge1‐xSnxlayers and compare the Sn location and redistributions for fully strained and partially relaxed films. Comparing the Sn‐distributions and their local surroundings we see a tendency for the Sn to locally cluster forming enriched regions, in the relaxed sample, while the majority of the enriched regions still remains embedded in the lattice planes. A small fraction of the Sn atoms is delocalized out of the lattice planes (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Soil mineral N retention and N2O emissions following combined application of 15N‐labelled fertiliser and weed residues
Authors: García‐Ruiz R. , Gómez‐Muñoz B. , Hatch D. J. , Bol R. , Baggs E. M. 
Published: September 2012

RATIONALEThe combination of plant residues with inorganic fertiliser‐N provides the potential to increase N‐use efficiency in agricultural fruit production systems, such as olive orchards. The development of weeds in the inter‐canopy area of olive orchards is encouraged as a novel strategy to reduce soil erosion. However, little is known about soil N retention or N2O production following the combined application of inorganic‐N with the mulched weed residues.METHODSEmissions of 15N‐N2O and soil mineral 15N retention were measured following combined applications of 15N‐labelled fertiliser and a range of olive crop weed residues to a silty loam soil under controlled conditions. These plant residues differed in their C:N ratios, lignin and polyphenol contents.RESULTSThe magnitude of soil 15N‐NO3– retention from combining plant residues and fertiliser‐N was highly dependent on potential N mineralisation (r = −0.96) and the (lignin + polyphenol)‐to‐N ratio (r = 0.98) of the residues. Fertiliser‐N‐derived retention was zero for a legume‐based mulch but up to 80% in the treatment containing plant residues with a high (lignin + polyphenol)‐to‐N ratio. N2O emissions increased after the addition of residues, and increased further (up to 128%) following the combined application of inorganic fertiliser and residues. Fertiliser‐derived 15N‐N2O was <1.4% of the total 14+15N‐N2O emission and <0.01% of the applied 15N‐NO3–. Enhanced N2O emissions following the application of residues and the fertiliser‐N values were positively correlated with the C:N ratio of the residue. Thus, combining organic‐ and inorganic‐N immobilised a significant proportion of the inorganic N with little increase in N2O, especially in low C:N ratio residues.CONCLUSIONSThe results demonstrate that whilst there is potential for N2O emissions to be controlled by combining weed residues and inorganic fertilisers, this is not easy to achieve as the magnitude and direction of interactions vary between different species due to their varying substrate qualities. Copyright © 2012 John Wiley & Sons, Ltd.
Understanding spatial variability of soil properties: a key step in establishing field‐ to farm‐scale agro‐ecosystem experiments
Authors: Peukert Sabine , Bol Roland , Roberts William , Macleod Christopher J. A. , Murray Phillip J. , Dixon Elizabeth R. , Brazier Richard E. 
Published: September 2012

RATIONALEThe spatial variability of soil properties is poorly understood, despite its importance in designing appropriate experimental sampling strategies. As preparation for a farm‐scale agro‐ecosystem services monitoring project, the 'North Wyke Farm Platform', there was a need to assess the spatial variability of key soil chemical and physical properties.METHODSThe field‐scale spatial variability of soil chemical (total N, total C, soil organic matter), soil physical properties (bulk density and particle size distribution) and stable isotope ratios (δ13C and δ15N values) was studied using geostatistical approaches in an intensively managed grassland.RESULTSThe scales over which stable isotopes vary (ranges: 212–258 m) were larger than those of the total nutrients, soil organic matter and bulk density (ranges: 84–170 m). Two visually and statistically distinct areas of Great Field (north and south) were identified in terms of co‐occurring high/low values of several soil properties.CONCLUSIONSThe resulting patterns of spatial variability suggest lower spatial variability of stable isotopes than that of total nutrients, soil organic matter and bulk density. Future sampling regimes should be conducted in a grid with <85 m distance between sampling locations to sufficiently capture the spatial variability of the measured soil properties on the 'North Wyke Farm Platform'. Consultation of the management histories of the sampled field revealed that it had previously comprised two fields with contrasting management histories, suggesting an effect of management legacy (>5 years) on the patterns of spatial variability. Copyright © 2012 John Wiley & Sons, Ltd.