bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the Mechanical Properties of Technical Fibers at Extreme Strain Rates
Authors: Bahners Thomas , Schloßer Uwe , Gutmann Jochen 
Published: February 2012

AbstractTechnical textiles can be subject to mechanical stress with strain rates far from the quasi‐static conditions of common standardized tests. The objective of the presented work was therefore to study the mechanical properties of technical yarns made of PA 6.6, PA 4.6, and PET under strain rates up to 200 s−1, making use of a “falling weight” apparatus. It can be summarized that the moduli at specific points of the stress–strain‐curve increase with the strain rate to values up to 50% higher than the data determined under quasi‐static strain. Saturation is observed for strain rates larger than 50 s−1. The analysis of failure morphology by scanning electron microscopy revealed molten material at the ends of broken fibers. This indicates thermal failure of the fibers due to local concentration of energy loading.magnified image
Influence of Electron Beam Irradiation on the Mechanical Properties of Vegetable‐Oil‐Based Biopolymers
Authors: Thunga Mahendra , Xia Ying , Gohs Uwe , Heinrich Gert , Larock Richard C. , Kessler Michael R. 
Published: February 2012

AbstractThe influence of electron beam (EB) irradiation on the mechanical properties of biopolymers from modified linseed oil is studied. The thermoset is prepared by copolymerizing norbornenyl‐functionalized linseed oil and dicyclopentadiene (DCPD) by ring‐opening metathesis polymerization (ROMP). EB irradiation of the bulk polymer results in a substantial increase in the crosslinking density. The residual carbon‐carbon double bonds remaining after ROMP are expected to act as further crosslinking sites upon exposure to the high‐energy electrons. The increase in the crosslinking density is studied by DMA and sol/gel fraction measurements from Soxhlet extraction. Tensile testing reveals that Young's modulus and tensile strength are enhanced after EB irradiation.magnified image
Structure Formation of Integral Asymmetric Composite Membranes of Polystyrene‐block‐Poly(2‐vinylpyridine) on a Nonwoven
Authors: Jung Adina , Rangou Sofia , Abetz Clarissa , Filiz Volkan , Abetz Volker 
Published: February 2012

AbstractThe formation of an integral asymmetric membrane composed of a cylinder‐forming polystyrene‐block‐poly(2‐vinylpyridine) on a nonwoven by using solvent casting followed by solvent/nonsolvent exchange (phase inversion) is reported for the first time. The influence of parameters such as solvent composition, evaporation time of the solution‐cast block copolymer film before phase inversion, and immersion bath temperature is demonstrated. The optimized membranes are characterized in terms of stimuli‐responsive water flux properties. The morphologies of the membranes as well as of the bulk of the block copolymer are imaged by scanning force microscopy, scanning electron microscopy, and transmission electron microscopy.magnified image
Thermal and Photochemical Crosslinking of Hyperbranched Polyphenylene With Organic Azides
Authors: Pötzsch Robert , Voit Brigitte 
Published: February 2012

AbstractHere, we report on the first example of crosslinking (CL) hyperbranched polyphenylene (hb–PPh) with a small molecule crosslinker 1,3,5‐tris(azidomethyl)benzene (TAMB). It was successfully shown that CL of the hb–PPh/TAMB (9:1) film is possible either thermally or photochemically making use of fundamentally different reaction mechanisms. Starting from a model reaction to prove the feasibility of the thermal CL reaction, we went on to check both the thermal and the photochemical crosslinkability of micrometer thick films. IR spectroscopy was furthermore used to confirm the CL process. Finally, the thin film morphology of the films before and after CL was investigated by AFM, revealing that the surface morphology was unaffected by the CL processes.
A theoretical analysis of a new finite volume scheme for second order hyperbolic equations on general nonconforming multidimensional spatial meshes
Authors: Bradji Abdallah 
Published: February 2012

AbstractWe consider the wave equation, on a multidimensional spatial domain. The discretization of the spatial domain is performed using a general class of nonconforming meshes which has been recently studied for stationary anisotropic heterogeneous diffusion problems, see Eymard et al. (IMAJ Numer Anal 30 (2010), 1009–1043). The discretization in time is performed using a uniform mesh. We derive a new implicit finite volume scheme approximating the wave equation and we prove error estimates of the finite volume approximate solution in several norms which allow us to derive error estimates for the approximations of the exact solution and its first derivatives. We prove in particular, when the discrete flux is calculated using a stabilized discrete gradient, the convergence order is
\documentclass{article} \usepackage{mathrsfs} \usepackage{amsmath} \pagestyle{empty} \begin{document} \begin{align*} h_\mathcal{D}\end{align*} \end{document}
(resp. k) is the mesh size of the spatial (resp. time) discretization. This estimate is valid under the regularity assumption
\documentclass{article} \usepackage{mathrsfs} \usepackage{amsmath} \pagestyle{empty} \begin{document} \begin{align*}u\in C^3(\lbrack 0,T\rbrack;C^2(\overline{\Omega}))\end{align*} \end{document}
for the exact solution u. The proof of these error estimates is based essentially on a comparison between the finite volume approximate solution and an auxiliary finite volume approximation. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
Determination of Aflatoxins in Medicinal Herbs by High‐performance Liquid Chromatography–Tandem Mass Spectrometry
Authors: Liu Lina , Jin Hongyu , Sun Lei , Ma Shuangcheng , Lin Ruichao 
Published: February 2012

ABSTRACTIntroductionWe report a rapid and accurate method to determine the natural occurrence of aflatoxins (AFs) B1, B2, G1 and G2 in medicinal herbs and the analysis of 174 commercial samples by this method.ObjectiveThe aim of the present work is to examine the occurrence of the aflatoxins B1, B2, G1 and G2 in common medicinal herbs.MethodologyThe AFs were extracted, purified by immunoaffinity column and analysed by high‐performance liquid chromatography–tandem quadrupole mass spectrometry with electrospray ionisation (HPLC–MS/MS).ResultsThe AFs can be separated within 6 min using an Agilent XDB C18‐column. The target analyte AFB1 could be detected at 0.14 µg/kg. A good linear relationship was found for AFG1 and AFB1 in 1–100 pg and AFG2 and AFB2 in 0.8–30 pg (r > 0.9995). The analyte recovery under three different spiking levels was 64–100% with the relative standard deviations (RSD) below 8.19%.ConclusionThis simple and accurate method effectively eliminates false positive detection and can be used to determine the AFs in medicinal herbs to control product quality. We found that in the 174 samples tested, 27 were contaminated with AFs. The incidences of AFB1, AFB2, AFG1 and AFG2 in the samples tested were 15.52%, 14.37%, 6.32% and 2.30%, respectively. We proposed 10 µg/kg total AFs and 5 µg/kg AFB1 as the reasonable maximum limits (ML) in medicinal herbs, and there are 10 samples (5.71% occurrence) in our test that exceeded this proposed limit. Copyright © 2012 John Wiley & Sons, Ltd.
The effect of water activity on the sorption and diffusion of water in thermosets based on polyester, vinyl ester, and novolac resins
Authors: Römhild S. , Hedenqvist M.S. , Bergman G. 
Published: February 2012

AbstractIn this work, the transport properties of water in various thermoset resins typically used for fiber‐reinforced plastic process equipment (vinyl ester, novolac, bisphenol‐A‐epoxy‐based polyester, and urethane‐modified vinyl ester) were systematically studied with a focus on the effects of water activity. Sorption and desorption studies were carried out in aqueous solutions (water activity = 0.78–1) with different salts (NaCl, MgCl2, Na2SO4, and KCl) and one nonionic substance (sucrose) within the temperature interval 65–95°C. It was found that the water concentration in thermoset resins with different chemical structures could be predicted from the water activity, regardless of the actual solute (salt or sucrose) in the aqueous solution. The water quasi‐equilibrium concentration decreased with decreasing water activity, whereas the average diffusion coefficient was considered to be independent of water activity in the studied water activity range. A relationship, based on a power law fit, was established describing the water concentration as a function of the water activity and the concentration of pure water. The relationship was independent of resin chemistry and temperature. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Systematic experimental study on mechanical behavior of PVB (polyvinyl butyral) material under various loading conditions
Authors: Liu Bohan , Sun Yueting , Li Yibing , Wang Yan , Ge Dongyun , Xu Jun 
Published: February 2012

AbstractThe mechanical behavior of polyvinyl butyral (PVB) significantly influences crashworthiness and energy mitigation abilities of windshields in terms of pedestrian safety. In this article, mechanical characteristics of PVB are experimentally studied. First, tension and compression experiments on PVB specimen are carried out under various quasi‐static loading rates. Fundamental mechanism of rate‐dependent behavior is investigated. Besides, dynamic tension and compression experimental data are compared to investigate the mechanical behavior of PVB in a whole strain rate region and it is found that PVB behaves as a visco‐elastic material under compressive loadings in both quasi‐static and dynamic situations; however, in tension experiments, stress–strain curves of PVB under dynamic loadings are elasto‐plastic while those under quasi‐static loadings are visco‐elastic. Considering all the unique characteristics of PVB's behavior, constitutive models are then established based on Zhu‐Wang‐Tang model mathematically. Further, unit volume energy absorption of every experiment in quasi‐static tension and compression are calculated as well as the stress intensify factor. In addition, visco‐elasticity part in the constitutive model is employed. Results may offer useful experiment data and important constitutive characteristics of PVB material to further studies of automotive crashworthiness and pedestrian protection. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
A study on electrical and thermal conductivities of ethylene–octene copolymer/expandable graphite composites
Authors: Svoboda Petr , Theravalappil Rajesh , Poongavalappil Sameepa , Vilcakova Jarmila , Svobodova Dagmar , Mokrejs Pavel , Blaha Antonin 
Published: February 2012

AbstractA series of ethylene–octene copolymer (EOC) composites have been prepared by melt‐mixing with different weight ratios of expandable graphite filler (0–50% by weight). Electrical conductivity [both alternating current (AC) and direct current (DC)] and thermal conductivity studies were carried out. Effect of filler loading and frequency on electrical conductivity was studied. DC conductivity has increased from 1.51 × 10−13 S cm−1 to 1.17 × 10−1 S cm−1. Percolation threshold by DC and also AC methods was observed at about 16 vol% of the filler. Real part of permittivity was found to be decreasing with increase in frequency while conductivity was increasing. Thermal conductivity was also found to be increasing gradually from 0.196 to 0.676 Wm−1 K−1 which is about 245% increase. Graphite not only increases the electrical and thermal conductivities but at and above 40 wt%, also acts as a halogen‐free, environmental friendly flame retardant. Shore‐A hardness of EOC/graphite composites shows that even with high graphite loading, the hardness is increased from about 50–68 only so that the rubbery nature of the composite is not affected very much. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Experimental study for starve‐fed single screw extrusion of thermoplastics
Authors: Wilczyński Krzysztof , Lewandowski Adrian , Wilczyński Krzysztof J. 
Published: February 2012

AbstractAn experimental study of the polymer behavior in a starve‐fed single screw extrusion is presented. Various polymeric materials, semicrystalline low density polyethylene (LDPE), polypropylene (PP), and (LDPE/PS) polyblends were investigated at various operating conditions. A “screw pulling‐out” technique was used to study polymer behavior along the screw. The solid conveying, melting position, the extent of starvation, and the fully filled regions were observed. Polymer samples were stripped off from the screw which was removed from the machine to investigate melting mechanism. It was seen that filling of the screw channel increases with the flow rate at a fixed screw speed, and decreases with the screw speed at a fixed flow rate. Contiguous solids melting mechanism was observed for flood fed extrusion, but it was not observed for starve‐fed extrusion. A new two‐stage physical model of polymer melting has been proposed with conductive mechanism for melting in the starve‐fed region and dispersed melting mechanism in the fully filled region. Melting action seems to be faster for starve feeding than for flood feeding, since the pellets are not compacted into a dense solid bed. It was observed that the pressure and power consumption considerably decrease with starvation. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Modern health worries and personality
Authors: Furnham Adrian , Strait Luciana , Hughes David J 
Published: February 2012

ABSTRACTUsing self‐report data, we investigated whether personality traits are associated with, or predictive of, modern health worries (MHWs), which are popular concerns that people have that their health is threatened by modernity. Three‐hundred and one British participants completed a questionnaire that measured MHWs, the Big Five personality traits and personal demographics. Results showed that openness‐to‐experience and conscientiousness were significantly correlated with MHWs and were significant predictors of MHWs. Those with high scores on openness‐to‐experience and conscientiousness showed higher MHWs scores. Religiousness was also shown to be strongly related to MHWs. Surprisingly, there were few significant associations between MHWs and trait neuroticism. It is concluded that MHWs are moderately associated with personality traits. Limitations of the study and suggestions for future research are also discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Protein determinants of phage T4 lysis inhibition
Authors: Moussa Samir H. , Kuznetsov Vladimir , Tran Tram Anh T. , Sacchettini James C. , Young Ry 
Published: February 2012

AbstractGenetic studies have established that lysis inhibition in bacteriophage T4 infections occurs when the RI antiholin inhibits the lethal hole‐forming function of the T holin. The T‐holin is composed of a single N‐terminal transmembrane domain and a ∼20 kDa periplasmic domain. It accumulates harmlessly throughout the bacteriophage infection cycle until suddenly causing permeabilization of the inner membrane, thereby initiating lysis. The RI antiholin has a SAR domain that directs its secretion to the periplasm, where it can either be inactivated and degraded or be activated as a specific inhibitor of T. Previously, it was shown that the interaction of the soluble domains of these two proteins within the periplasm was necessary for lysis inhibition. We have purified and characterized the periplasmic domains of both T and RI. Both proteins were purified in a modified host that allows disulfide bond formation in the cytoplasm, due to the functional requirement of conserved disulfide bonds. Analytical centrifugation and circular dichroism spectroscopy showed that RI was monomeric and exhibited ∼80% alpha‐helical content. In contrast, T exhibited a propensity to oligomerize and precipitate at high concentrations. Incubation of RI with T inhibits this aggregation and results in a complex of equimolar T and RI content. Although gel filtration analysis indicated a complex mass of 45 kDa, intermediate between the predicted 30 kDa heterodimer and 60 kDa heterotetramer, sedimentation velocity analysis indicated that the predominant species is the former. These results suggest that RI binding to T is necessary and sufficient for lysis inhibition.
Activity, stability, and structure of metagenome‐derived LC11‐RNase H1, a homolog of Sulfolobus tokodaii RNase H1
Authors: Nguyen Tri‐Nhan , Angkawidjaja Clement , Kanaya Eiko , Koga Yuichi , Takano Kazufumi , Kanaya Shigenori 
Published: February 2012

AbstractMetagenome‐derived LC11‐RNase H1 is a homolog of Sulfolobus tokodaii RNase H1 (Sto‐RNase H1). It lacks a C‐terminal tail, which is responsible for hyperstabilization of Sto‐RNase H1. Sto‐RNase H1 is characterized by its ability to cleave not only an RNA/DNA hybrid but also a double‐stranded RNA (dsRNA). To examine whether LC11‐RNase H1 also exhibits both RNase H and dsRNase activities, LC11‐RNase H1 was overproduced in Escherichia coli, purified, and characterized. LC11‐RNase H1 exhibited RNase H activity with similar metal ion preference, optimum pH, and cleavage mode of substrate with those of Sto‐RNase H1. However, LC11‐RNase H1 did not exhibit dsRNase activity at any condition examined. LC11‐RNase H1 was less stable than Sto‐RNases H1 and its derivative lacking the C‐terminal tail (Sto‐RNase H1ΔC6) by 37 and 13°C in Tm, respectively. To understand the structural bases for these differences, the crystal structure of LC11‐RNase H1 was determined at 1.4 Å resolution. The LC11‐RNase H1 structure is highly similar to the Sto‐RNase H1 structure. However, LC11‐RNase H1 has two grooves on protein surface, one containing the active site and the other containing DNA‐phosphate binding pocket, while Sto‐RNase H1 has one groove containing the active site. In addition, LC11‐RNase H1 contains more cavities and buried charged residues than Sto‐RNase H1. We propose that LC11‐RNase H1 does not exhibit dsRNase activity because dsRNA cannot fit to the two grooves on protein surface and that LC11‐RNase H1 is less stable than Sto‐RNase H1ΔC6 because of the increase in cavity volume and number of buried charged residues.
Clustering algorithm based on mutual K‐nearest neighbor relationships
Authors: Hu Zhen , Bhatnagar Raj 
Published: February 2012

AbstractClustering algorithms for data with varying densities have been investigated in the past and there are some data situations and clustering needs that are not handled well by these algorithms. We present here an algorithm for such situations in which multiple, possibly overlapping, clusters exist and need to be identified by their density as the defining characteristic. In this paper, we define the idea of mutual K‐nearest neighbors (MKNN) relationship based on inter‐point affinities and use it as a basis for discovering the above‐mentioned types of clusters. With a synthetic and two real‐world datasets we show that our algorithm delivers the type of clustering results and robustness that we seek to achieve, and the performance is better than what is achievable by other algorithms. Statistical Analysis and Data Mining 2012
Progressive collapse behavior of rotor‐type diagrid buildings
Authors: Kim Jinkoo , Kong Jieun 
Published: February 2012

SUMMARYIn this study, the progressive collapse‐resisting capacities of axi‐symmetric or rotor‐type diagrid structural system buildings were evaluated based on arbitrary column removal scenario. For analysis models, 33‐story buildings with cylindrical, convex, concave and gourd shapes were designed, and their nonlinear static and dynamic analysis results were compared. The effect of design variables such as the number of total stories, slope of diagrids and the location of removed members was also investigated. According to the analysis results, the rotor‐type diagrid structures showed sufficient progressive collapse‐resisting capacity regardless of the differences in shapes when a couple of diagrids were removed from the first story. The design parameter such as building height and the slope of the diagrids did not affect the results significantly as long as they were designed to meet the current design code. Copyright © 2012 John Wiley & Sons, Ltd.
Mapping of the ms8 male sterility gene in sweet pepper (Capsicum annuum L.) on the chromosome P4 using PCR-based markers useful for breeding programmes
Authors: Bartoszewski Grzegorz , Waszczak Cezary , Gawroński Piotr , Stępień Iwona , Bolibok-Brągoszewska Hanna , Palloix Alain , Lefebvre Véronique , Korzeniewska Aleksandra , Niemirowicz-Szczytt Katarzyna 
Published: February 2012

AbstractThe nuclear male sterility gene ms8 is expected to facilitate the production of sweet pepper (Capsicum annuum L.) hybrids as it provides means for hybridization without the labor-intensive hand emasculation of female inbred lines. The development of molecular markers linked to ms8 locus will help the breeding practice for the selection of hybrid parental lines. In this study, F2 population resulting from a cross between the sweet pepper male sterile line 320 and the male fertile variety Elf was used to identify DNA markers linked to the ms8 locus. With the use of RAPD–BSA technique, seven markers linked to the ms8 locus were found. Four of them were converted into SCAR markers. In addition, two COSII/CAPS markers linked to the ms8 locus were identified. Comparative mapping with reference pepper maps indicated that the ms8 locus is located on the lower arm of the pepper chromosome P4. Identified markers are useful for molecular breeding, however, at present markers tightly linked to ms8 locus are still lacking. Identification of molecular markers linked to the ms8 locus and determination of its chromosomal localization are useful for fine mapping and also provide the perspective for ms8 gene cloning.
A multi-layer model for nonlinear internal wave propagation in shallow water
Authors: Liu Philip L.-F. , Wang Xiaoming 
Published: February 2012

AbstractIn this paper, a multi-layer model is developed for the purpose of studying nonlinear internal wave propagation in shallow water. The methodology employed in constructing the multi-layer model is similar to that used in deriving Boussinesq-type equations for surface gravity waves. It can also be viewed as an extension of the two-layer model developed by Choi & Camassa. The multi-layer model approximates the continuous density stratification by an $N$-layer fluid system in which a constant density is assumed in each layer. This allows the model to investigate higher-mode internal waves. Furthermore, the model is capable of simulating large-amplitude internal waves up to the breaking point. However, the model is limited by the assumption that the total water depth is shallow in comparison with the wavelength of interest. Furthermore, the vertical vorticity must vanish, while the horizontal vorticity components are weak. Numerical examples for strongly nonlinear waves are compared with laboratory data and other numerical studies in a two-layer fluid system. Good agreement is observed. The generation and propagation of mode-1 and mode-2 internal waves and their interactions with bottom topography are also investigated.