bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydraulic properties at the North Sea island of Borkum derived from joint inversion of magnetic resonance and electrical resistivity soundings
Authors: Günther T. , Müller-Petke M.
Published: September 2012

Abstract. For reliably predicting the impact of climate changes on salt/freshwater systems below barrier islands, a long-term hydraulic modelling is inevitable. As input we need the parameters porosity, salinity and hydraulic conductivity at the catchment scale, preferably non-invasively acquired with geophysical methods. We present a methodology to retrieve the searched parameters and a lithological interpretation by the joint analysis of magnetic resonance soundings (MRS) and vertical electric soundings (VES). Both data sets are jointly inverted for resistivity, water content and decay time using a joint inversion scheme. Coupling is accomplished by common layer thicknesses. We show the results of three soundings measured on the eastern part of the North Sea island of Borkum. Pumping test data is used to calibrate the petrophysical relationship for the local conditions in order to estimate permeability from nuclear magnetic resonance (NMR) data. Salinity is retrieved from water content and resistivity using a modified Archie equation calibrated by local samples. As a result we are able to predict porosity, salinity and hydraulic conductivities of the aquifers, including their uncertainties. The joint inversion significantly improves the reliability of the results. Verification is given by comparison with a borehole. A sounding in the flooding area demonstrates that only the combined inversion provides a correct subsurface model. Thanks to the joint application, we are able to distinguish fluid conductivity from lithology and provide reliable hydraulic parameters as shown by uncertainty analysis. These findings can finally be used to build groundwater flow models for simulating climate changes. This includes the improved geometry and lithological attribution, and also the parameters and their uncertainties.
Regionalised spatiotemporal rainfall and temperature models for flood studies in the Basque Country, Spain
Authors: Cowpertwait P. , Ocio D. , Collazos G. , de Cos O. , Stocker C.
Published: September 2012

Abstract. A spatial-temporal point process model of rainfall is fitted to data taken from three homogeneous regions in the Basque Country, Spain. The model is the superposition of two spatial-temporal Neyman-Scott processes, in which rain cells are modelled as discs with radii that follow exponential distributions. In addition, the model includes a parameter for the radius of storm discs, so that rain only occurs when both a cell and a storm disc overlap a point. The model is fitted to data for each month, taken from each of the three homogeneous regions, using a modified method of moments procedure that ensures a smooth seasonal variation in the parameter estimates. Daily temperature data from twenty three sites are used to fit a stochastic temperature model. A principal component analysis of the maximum daily temperatures across the sites indicates that 92% of the variance is explained by the first component, implying that this component can be used to account for spatial variation. A harmonic equation with autoregressive error terms is fitted to the first principal component. The temperature model is obtained by regressing the maximum daily temperature on the first principal component, an indicator variable for the region, and altitude. This, together with scaling and a regression model of temperature range, enables hourly temperatures to be predicted. Rainfall is included as an explanatory variable but has only a marginal influence when predicting temperatures. A distributed model (TETIS; Francés et al., 2007) is calibrated for a selected catchment. Five hundred years of data are simulated using the rainfall and temperature models and used as input to the calibrated TETIS model to obtain simulated discharges to compare with observed discharges. Kolmogorov-Smirnov tests indicate that there is no significant difference in the distributions of observed and simulated maximum flows at the same sites, thus supporting the use of the spatiotemporal models for the intended application.
Automated detection of snow avalanche deposits: segmentation and classification of optical remote sensing imagery
Authors: Lato M. J. , Frauenfelder R. , Bühler Y.
Published: September 2012

Abstract. Snow avalanches in mountainous areas pose a significant threat to infrastructure (roads, railways, energy transmission corridors), personal property (homes) and recreational areas as well as for lives of people living and moving in alpine terrain. The impacts of snow avalanches range from delays and financial loss through road and railway closures, destruction of property and infrastructure, to loss of life. Avalanche warnings today are mainly based on meteorological information, snow pack information, field observations, historically recorded avalanche events as well as experience and expert knowledge. The ability to automatically identify snow avalanches using Very High Resolution (VHR) optical remote sensing imagery has the potential to assist in the development of accurate, spatially widespread, detailed maps of zones prone to avalanches as well as to build up data bases of past avalanche events in poorly accessible regions. This would provide decision makers with improved knowledge of the frequency and size distributions of avalanches in such areas. We used an object–oriented image interpretation approach, which employs segmentation and classification methodologies, to detect recent snow avalanche deposits within VHR panchromatic optical remote sensing imagery. This produces avalanche deposit maps, which can be integrated with other spatial mapping and terrain data. The object-oriented approach has been tested and validated against manually generated maps in which avalanches are visually recognized and digitized. The accuracy (both users and producers) are over 0.9 with errors of commission less than 0.05. Future research is directed to widespread testing of the algorithm on data generated by various sensors and improvement of the algorithm in high noise regions as well as the mapping of avalanche paths alongside their deposits.
Liquid–Solid Sample Preparation Followed by Headspace Solid-Phase Microextraction Determination of Multiclass Pesticides in Soil
Authors: Ðurović Rada D , Ðorðević Tijana M , Šantrić Ljiljana R
Published: September 2012

This paper describes development and validation of a multiresidue method for the determination of five pesticides (terbufos, prochloraz, chloridazon, pendimethalin, and fluorochloridone) belonging to different pesticide groups in soil samples by GC/MS, followed by its application in the analysis of some agricultural soil samples. The method is based on a headspace solid-phase microextraction method. Microextraction conditions, namely temperature, extraction time, and NaCl content, were tested and optimized using a 100 μm polydimethylsiloxane fiber. Three extraction solvents [methanol, methanol–acetone (1 + 1, v/v), and methanol–acetone–hexane (2 + 2 + 1, v/v/v)] and the optimum number of extraction steps within the sample preparation stage were optimized for the extraction procedure. LOD values for all the studied compounds were less than 12 μg/kg. Recovery values for multiple analyses of soil samples fortified at 30 μg/kg of each pesticide were higher than 64%. The method was proven to be repeatable, with RSD lower than 15%.
Application of RP-HPLC-Diode Array Detector after SPE to the Determination of Pesticides in Pepper Samples
Authors: Tuzimski Tomasz
Published: September 2012

The application of HPLC-diode array detector (DAD) after SPE for identification and quantitative analysis of pesticides in red and green pepper samples is demonstrated. An HPLC procedure on an RP column (C18) was developed for analysis of selected pesticides from different chemical groups: metamitron, metalaxyl, linuron, and prometryn. Average recoveries for C18 Polar Plus cartridges and solvents by the proposed RP-HPLC-DAD method after SPE are presented. Average recoveries from the spiked samples and the SDs were 22.5 ± 2.2, 138.0 ± 4.1, 78.6 ± 2.8, and 109.2 ± 2.3% for metamitron, metalaxyl, linuron, and prometryn, respectively, at concentrations of 7 μg/g in the plant material. The efficiency of the SPE procedure was evaluated using real food samples. The quantities of prometryn, linuron, metalaxyl, and metamitron determined were in the ranges of 0.02–2.24 μg/g (n = 24), 0.08–1.01 μg/g (n = 9), 1.61–2.28 μg/g (n = 4), and 0.05–1.07 μg/g (n = 3), respectively, in plant material sampled in 2011. The method was validated for precision, repeatability, and accuracy.
Design of an Adaptive PD Controller for the Weight-Independent Motion Control of a Mobile Robot
Authors: Kwak Hwan-Joo , Park Gwi-Tae
Published: September 2012

Previous research on mobile robots has been based on models of mobile robots with invariant weight parameters. However, the most practical mobile robots that bear heavy burdens have varying weights and centres of gravity. This paper suggests a design for an adaptive PD controller that estimates and adapts to the weight-related parameters of robots that bear varying heavy burdens. Using the suggested adaptive PD controller, the motion of mobile robots can be independent of the weight-related parameters and the operational performance is confirmed by target tracking simulations.
Adaptation of Escherichia coli ATCC 8739 to 11% NaCl
Authors: How Jian Ann , Lim Joshua Z. R. , Goh Desmond J. W. , Ng Wei Chuan , Oon Jack S. H. , Lee Kun Cheng , Lee Chin How , Ling Maurice H. T.
Published: September 2012

Escherichia coli (E. coli) is a nonhalophilic microbe and used to indicate faecal contamination. Salt (sodium chloride, NaCl) is a common food additive and is used in preservatives to encounter microbial growth. The effect of how E. coli interacts with the salt present in the human diet is unclear. Thus, it is important to investigate this relationship. In order to adapt and survive the changes in the environment, E. coli may undergo halophilization. In this study, we observed the genetic changes and growth kinetics of E. coli ATCC 8739 under 3%–11% NaCl over 80 passages. Our results suggest that E. coli adapted to 1% increase in NaCl every month with a successful adaptation to 11% NaCl. Gram staining and PCR/RFLP showed that the cultures are Gram negative and the DNA profiles of all 4 replicates to be similar, suggesting that the cultures had not been contaminated.
Selenium Proteins Containing SelenocysteineUpdate based on the original article by August Böck,Encyclopedia of Inorganic ChemistrySecond Edition, © 2005, John Wiley & Sons, Ltd.
Authors: Self William T.
Published: September 2012

Selenium is incorporated in the form of the nonstandard amino acid selenocysteine into selected proteins of organisms belonging to all three lines of descent. The majority of these proteins, which contain selenocysteine in the active site, catalyze oxidation–reduction reactions and are involved in numerous biochemical and regulatory processes, which in many cases are indispensable for the organism. Because of significant differences in the chemical reactivity of selenocysteine in comparison to cysteine, selenoenzymes display a greatly increased rate of catalysis and, in some cases, have an extended substrate specificity. Apart from its biochemical function, selenocysteine is also unique since its incorporation is DNA‐encoded and its cotranslational insertion follows a route independent in many features from the path of insertion of the 20 classical amino acids. Selenocysteine, therefore, can be considered the 21st amino acid.
Precursor‐Bound Nif
EN
: Insights into Nitrogenase Cofactor Assembly
Authors: Wiig Jared A. , Lee Chi Chung , Hu Yilin , Ribbe Markus W.
Published: September 2012

The biosynthesis of the iron–molybdenum cofactor (FeMoco) of nitrogenase is one of the most complicated processes in metalloprotein biochemistry. Here we review the recent progress on the investigation of NifEN, an important scaffold protein for the maturation of an iron‐only precursor to a molybdenum‐ and homocitrate‐containing FeMoco. The recently solved crystal structure of the precursor‐bound form of NifEN is discussed in detail, which provides important insights into the biosynthetic mechanism of nitrogenase. In addition, the functional and spectroscopic features of NifEN are discussed.
Control of rotation extrusion over shish‐kebab crystal alignment in polyethylene pipe and its effect on the pipe's crack resistance
Authors: Nie Min , Wang Qi
Published: September 2012

A self‐designed rotation extrusion system was adopted to extrude polyethylene (PE) pipe. The experimental results showed that when the mandrel and die rotated in the same directions during the PE pipe extrusion, apart from the axial stress, all polymer melts in PE pipes were also subjected to the hoop stress so that the formed shish‐kebab crystal in the whole pipe deviated from the axial direction greatly, which was further fixed by the double cooling on both inner and outer walls. As a result, the PE pipe with better resistance to slow crack growth was prepared. As compared to the PE pipe produced by the convention extrusion, the crack initiation time of the PE pipe manufactured by the novel method increased from 27 to 174 h, by 544%. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of a novel poly(ester‐urethane) containing short lactate sequences and PEG moieties
Authors: He Xuelei , Xiao Congming , Xu Jing
Published: September 2012

A novel poly(ester‐urethane) with tailor‐made structure was prepared by using lactic acid (LA) as starting material through a combination of two facile common reactions. First, a diol was prepared via the esterification between LA and poly(ethylene glycol) (PEG) with low molecular weight. Subsequently, the poly(ester‐urethane) was synthesized through the addition polymerization of the LA‐based diol and toluene 2,4‐diisocyanate with 1,4‐butanediol as chain extender. The structure, morphology, and properties of intermediate and the poly(ester‐urethane) were analyzed with Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography (GPC), X‐ray diffraction, differential scanning calorimetry, polarizing optical microscopy, and thermogravimetric analysis. The results indicated that the intermediate was a diol of conjugating quite short lactate sequences with PEG oligomer, and the structure of the poly(ester‐urethane) was as expected. The thermal transition, thermal decomposition temperature, and crystallinity of the polymer samples depended on the molecular size of PEG. In vitro degradation property of the poly(ester‐urethane) also relied on the molecular weight of PEG. The weight loss percentages varied from 11 to 36% after 12‐days immersing in phosphate‐buffer saline at 37°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
A virtual metrology system based on least angle regression and statistical clustering
Authors: Susto Gian Antonio , Beghi Alessandro
Published: September 2012

In semiconductor manufacturing plants, monitoring physical properties of all wafers is crucial to maintain good yield and high quality standards. However, such an approach is too costly, and in practice, only few wafers in a lot are actually monitored. Virtual metrology (VM) systems allow to partly overcome the lack of physical metrology. In a VM scheme, tool data are used to predict, for every wafer, metrology measurements. In this paper, we present a VM system for a chemical vapor deposition (CVD) process. On the basis of the available metrology results and of the knowledge, for every wafer, of equipment variables, it is possible to predict CVD thickness. In this work, we propose a VM module based on least angle regression to overcome the problem of high dimensionality and model interpretability. We also present a statistical distance‐based clustering approach for the modeling of the whole tool production. The proposed VM models have been tested on industrial production data sets. Copyright © 2012 John Wiley & Sons, Ltd.
Single‐step modified QuEChERS for determination of chlorothalonil in shallot (Allium ascalonicum) using GC‐μECD and confirmation via mass spectrometry
Authors: Rahman Md. Musfiqur , Park Jong‐Hyouk , Abd El‐Aty A. M. , Choi Jeong‐Heui , Bae Hey Ree , Yang Angel , Park Ki Hun , Shim Jae‐Han
Published: September 2012

A single extraction method was developed for chlorothalonil in shallot using gas chromatography with an electron capture detector (GC‐μECD). Samples were extracted with single‐step modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method using ethyl acetate as an extraction solvent. Significant matrix effects were observed, and the calibration curve was constructed from the matrix. The linearity of the analytical response across the studied range of concentrations (0.01–1.00 mg/L) was excellent, obtaining a correlation coefficient (r2) of 0.996. >0.996. Recovery studies were carried out on spiked shallot blank samples, at two concentration levels (0.4 and 2.0 mg/kg) with three replicates performed at each level. Mean recoveries of 97.2–104.9% with RSDs of 1.3–2.7% were obtained. The method is demonstrated to be suitable for the determination of chlorothalonil in shallot. The dissipation rates of chlorothalonil were described using first‐order kinetics, and its half‐life was 2.8 days. Based on the dissipation pattern of the pesticide residues, the pre‐harvest residue limit (PHRL) was also calculated. Residues were confirmed via mass spectrometry. Copyright © 2012 John Wiley & Sons, Ltd.
Predicting the Enantioselectivity of the Copper‐Catalysed Cyclopropanation of Alkenes by Using Quantitative Quadrant‐Diagram Representations of the Catalysts
Authors: Aguado‐Ullate Sonia , Urbano‐Cuadrado Manuel , Villalba Isabel , Pires Elísabet , García José I. , Bo Carles , Carbó Jorge J.
Published: September 2012

We present a new methodology to predict the enantioselectivity of asymmetric catalysis based on quantitative quadrant‐diagram representations of the catalysts and quantitative structure–selectivity relationship (QSSR) modelling. To account for quadrant occupation, we used two types of molecular steric descriptors: the Taft–Charton steric parameter (ν(Charton)) and the distance‐weighted volume (VW). By assigning the value of the steric descriptors to each of the positions of the quadrant diagram, we generated the independent variables to build the multidimensional QSSR models. The methodology was applied to predict the enantioselectivity in the cyclopropanation of styrene catalysed by copper complexes. The dataset comprised 30 chiral ligands belonging to four different oxazoline‐based ligand families: bis‐ (Box), azabis‐ (AzaBox), quinolinyl‐ (Quinox) and pyridyl‐oxazoline (Pyox). In the first‐order approximation, we generated QSSR models with good predictive ability (r2=0.89 and q2=0.88). The derived stereochemical model indicated that placing very large groups at two diagonal quadrants and leaving free the other two might be enough to obtain an enantioselective catalyst. Fitting the data to a higher‐order polynomial, which included crossterms between the descriptors of the quadrants, resulted in an improvement of the predicting ability of the QSSR model (r2=0.96 and q2=0.93). This suggests that the relationship between the steric hindrance and the enantioselectivity is non‐linear, and that bulky substituents in diagonal quadrants operate synergistically. We believe that the quantitative quadrant‐diagram‐based QSSR modelling is a further conceptual tool that can be used to predict the selectivity of chiral catalysts and other aspects of catalytic performance.
Preparation of Stable Low‐Oxidation‐State Group 14 Element Amidohydrides and Hydride‐Mediated Ring‐Expansion Chemistry of N‐Heterocyclic Carbenes
Authors: Al‐Rafia S. M. Ibrahim , McDonald Robert , Ferguson Michael J. , Rivard Eric
Published: September 2012

Various low oxidation state (+2) group 14 element amidohydride adducts, IPr⋅EH(BH3)NHDipp (E=Si or Ge; IPr=[(HCNDipp)2C:], Dipp=2,6‐iPr2C6H3), were synthesized. Thermolysis of the reported adducts was investigated as a potential route to Si‐ and Ge‐based clusters; however, unexpected transmetallation chemistry occurred to yield the carbene–borane adduct, IPr⋅BH2NHDipp. When a solution of IPr⋅BH2NHDipp in toluene was heated to 100 °C, a rare CN bond‐activation/ring‐expansion reaction involving the bound N‐heterocyclic carbene donor (IPr) transpired.
Origin of the SN2 Benzylic Effect: Contributions by π Delocalization and Field/Inductive Effects
Authors: Rawlings Robert E. , McKerlie Adam K. , Bates Daniel J. , Mo Yirong , Karty Joel M.
Published: September 2012

Historically, the SN2 benzylic effect is attributed to a conjugative stabilization between the phenyl ring and the reaction center in the transition state. However, recent papers have cast doubt on this explanation. We have therefore investigated the origin of the SN2 benzylic effect for two different gas‐phase SN2 reactions, F– + C6H5CH2F and Cl– + C6H5CH2Cl, by carrying out two separate computational methodologies on each system – a vinylogue extrapolation (VE) methodology and a block‐localized wavefunction (BLW) methodology. The contributions we examined were (1) delocalization involving the ring's π system, and (2) field/inductive effects of the ring. For the fluoride and chloride reactions, the VE methodology suggests that delocalization contributes to a lowering of the reaction's energy barrier by 3.1 and 1.7 kcal/mol, respectively, and the BLW calculations suggest that delocalization contributes to lowering the barrier by 3.65 and 5.47 kcal/mol, respectively. Both methodologies therefore agree that π delocalization is a significant contributor to the benzylic effect. Furthermore, the VE methodology indicates that field/inductive effects also contribute to lowering the barriers by 2.2 and 3.2 kcal/mol, suggesting that a separate repulsive interaction serves to increase the barrier by 1.5 and 3.3 kcal/mol, respectively.
Toll-Like Receptor 2 and Palmitic Acid Cooperatively Contribute to the Development of Nonalcoholic Steatohepatitis Through Inflammasome Activation in Mice
Authors: Miura Kouichi , Yang Ling , van Rooijen Nico , Brenner David A. , Ohnishi Hirohide , Seki Ekihiro
Published: September 2012

Innate immune signaling associated with Toll-like receptors (TLRs) is a key pathway involved in the progression of nonalcoholic steatohepatitis (NASH). Here we show that both TLR2 and palmitic acid are required for activation of the inflammasome, interleukin (IL)-1α, and IL-1β, resulting in the progression of NASH. Wild-type (WT) and TLR2−/− mice were fed a choline-deficient amino acid–defined (CDAA) diet for 22 weeks to induce NASH. Bone marrow–transplanted TLR2 chimeric mice were generated after the recipient mice were lethally irradiated. Kupffer cells and hepatic stellate cells (HSCs) were isolated from WT mice and stimulated with TLR2 ligand and/or palmitic acid. WT mice on the CDAA diet developed profound steatohepatitis and liver fibrosis. In contrast, TLR2−/− mice had suppressed progression of NASH. Although both Kupffer cells and HSCs respond to TLR2 ligand, TLR2 bone marrow chimeric mice demonstrated that Kupffer cells were relatively more important than HSCs in TLR2-mediated progression of NASH.

In vitro

, palmitic acid alone did not increase TLR2 signaling-target genes, including cytokines and inflammasome components in Kupffer cells and HSCs. The TLR2 ligand increased Nod-like receptor protein 3, an inflammasome component, in Kupffer cells but not in HSCs. In the presence of TLR2 ligand, palmitic acid did induce caspase-1 activation and release of IL-1α and IL-1β in Kupffer cells; however, these effects were not observed in HSCs.

In vivo

, WT mice on the CDAA diet showed increased caspase-1 activation in the liver and elevated serum levels of IL-1α and IL-1β levels, which were suppressed in TLR2−/− mice.

Conclusion:

TLR2 and palmitic acid cooperatively activate the inflammasome in Kupffer cells and/or macrophages in the development of NASH.
White matter changes in primary dystonia determined by 2D distribution analysis of diffusion tensor images
Authors: Vo An , Eidelberg David , Uluǧ Aziz M.
Published: September 2012

Purpose:

To determine brain tissue affected by dystonia by making group comparison of parameter‐based diffusion tensor imaging (DTI) distributions of patients with control subjects. A 2D distribution analysis of mean diffusivity and fractional anisotropy index was used for modeling brain tissues according to the inherent diffusion characteristics.

Materials and Methods:

Seven affected carriers of the DYT1 dystonia mutation and eight healthy control subjects were imaged for a previous study. We employed a 2D distribution analysis of all the diffusion voxels and a four compartmental brain model for group comparison of the dystonia subjects and controls.

Results:

Our analysis showed disease involvement in the white matter of the patients. Excellent tissue characterization was achieved automatically using the 2D distribution analysis based on a physical brain model.

Conclusion:

This 2D analysis implicated white matter in dystonia and could be useful as a screening tool in diseases with unknown pathologies. J. Magn. Reson. Imaging 2013;37:59–66. © 2012 Wiley Periodicals, Inc.
An efficient method for purification of nonspecific lipid transfer protein‐1 from rice seeds using kiwifruit actinidin proteolysis and ion exchange chromatography
Authors: Ghobadi Sirous , Yousefi Fakhroddin , Khademi Fatemeh , Padidar Samira , Mostafaie Ali
Published: September 2012

Plant nonspecific lipid transfer proteins are small basic proteins that transport phospholipids between membranes and are subdivided into two subfamilies, nsLTP1 (9 kDa) and nsLTP2 (7 kDa). LTPs have potential application in the defense reactions against pathogens and the drug delivery systems. Many efforts have been made for purification of different nsLTPs from various plants; however, most of them used successive purification procedures. We have developed a relatively simple and efficient method for the purification of rice nsLTP1, based on the proteolytic activity of kiwifruit actinidin on the rice seed extract and one‐step chromatographic procedure on a CM‐Sepharose column. The purity of protein was determined by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). The isolated LTP1 migrated as a homogenous polypeptide with molecular mass of 9 kDa that confirms the efficiency of actinidin on the digestion of major contaminations present in the rice seed extract without any harmful effect on the LTP1. The advantages of using proteolytic activity of actinidin in purifying rice LTP1 includes the reduced separation time allowing the purification of LTP1 in one‐step chromatographic procedure, low costing, high efficiency, and the relative simplicity of the method.
A Serrin criterion for compressible nematic liquid crystal flows
Authors: Huang Xiangdi , Wang Yun
Published: September 2012

This paper is concerned with a simplified system, proposed by Ericksen and Leslie, modeling the flow of nematic liquid crystals. We establish a blowup criterion for three‐dimensional compressible nematic liquid crystal flows, which is analogous to the well‐known Serrin's blowup criterion for three‐dimensional incompressible viscous flows. Copyright © 2012 John Wiley & Sons, Ltd.
Preparation and properties of biocomposites composed of sorbitol‐based epoxy resin, pyrogallol–vanillin calixarene, and wood flour
Authors: Shimasaki Toshiaki , Yoshihara Satoru , Shibata Mitsuhiro
Published: September 2012

The reaction of pyrogallol (PG) and vanillin (VN), both of which are derived from plant resources, in the presence of p‐toluenesulfonic acid gave PG–VN calixarene (PGVNC) mainly composed of guaiacyl pyrogallol[4]arene. After sorbitol polyglycidyl ether (SPE) was mixed with PGVNC in tetrahydrofuran at an optimized epoxy/hydroxy ratio 1/2.65, the obtained SPE/PGVNC solution was mixed with wood flour (WF), prepolymerized at 150°C, and subsequently compressed at 190°C for 3 h to give SPE–PGVNC/WF biocomposites with WF content 0–20 wt%. The tan δ peak temperature of SPE–PGVNC was 148.1°C, which was much higher than that of the SPE cured with petroleum‐based phenol novolac (SPE–PN) at an optimized epoxy/hydroxy ratio 1/1. Although tan δ peak temperature slightly decreased with increasing WF content, the storage moduli of the SPE–PGVNC/WF biocomposites in the rubbery state at more than 150°C were much higher than those of SPE–PGVNC and SPE–PN. Also, the tensile modulus and strength for SPE–PGVNC/WF increased with increasing WF content. Field emission‐scanning electron microscopy analysis of the biocomposites revealed that WF is tightly incorporated into the crosslinked epoxy resins. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Development of novel porous nasal scaffold using injection molding
Authors: Teng Ping‐Tun , Chern Ming‐Jyh , Shen Yung‐Kang , Chiang Yuh‐Chyun
Published: September 2012

Porous scaffolds fabricated from biodegradable polymers have been widely used and play a vital role in tissue engineering andin situtissue reconstruction. This study presents a novel fabrication technique involving injection molding and conventional particulate leaching (IM/PL) to obtain the L‐shaped nasal scaffold for rhinoplasty. The results indicate that the porous nasal scaffold made by the IM/PL method shows the acceptable biocompatibility and degradation. The nasal scaffold may degrade well after surgery and the cartilage tissue may grow well in it. This IM/PL technique may replace the traditional artificial silicone filler and reduce the surgery cost. POLYM. ENG. SCI. 2013. © 2012 Society of Plastics Engineers
Analytic formalism for current crowding in light emitting diodes
Authors: Lee Kyu‐Seok
Published: September 2012

This paper presents an analytic approach to simulating current crowding (CC) in light‐emitting diodes with parallel p‐ and n‐contacts. The electrical potential difference across the p–i–n layers is derived from the Laplace equation, whereas the current density through the p–i–n layers is obtained from the current density – voltage relation of a single‐diode model. Since these two properties influence each other, they are calculated iteratively. It is found that CC depends on the applied voltage (or the average current density), the sheet resistances of the p‐ and the n‐contact layers, the width of the active region, and the specific series resistance and ideality factor of the p–i–n layers.
The predictability of precipitation episodes during the West African dry season
Authors: Davis Jenny , Knippertz Peter , Fink Andreas H.
Published: September 2012

Precipitation episodes in tropical West Africa (7–15°N, 10°W–10°E) during the dry season from November to March are rare, but can have significant impacts on human activities reaching from greening of pastures to spoiling harvests and health implications. Previous work has shown a link between these unseasonal rainfalls and extratropical disturbances via a decrease of surface pressure over the Sahara/Sahel and a subsequent inflow of moist air from the Gulf of Guinea. This paper supports the previously stated hypothesis that the extratropical influence leads to a high rainfall predictability through a careful analysis of operational 5 day forecasts from the European Centre for Medium‐Range Weather Forecasts' (ECMWF) ensemble prediction system (EPS), which are evaluated using Global Precipitation Climatology Project (GPCP) and Tropical Rainfall Measuring Mission (TRMM) precipitation estimates for the 11 dry seasons 1998/99‐2008/09. The long‐term regional average of ensemble‐mean precipitation lies between the two observational datasets, with GPCP being considerably wetter. Temporal correlations between the ensemble mean and observations are 0.8. Standard probabilistic evaluation methods such as reliability and relative operating characteristic (ROC) diagrams indicate remarkably good reliability, sharpness and skill across a range of precipitation thresholds. However, a categorical verification focusing on the most extreme ensemble mean values indicates too many false alarms. Despite the considerable observational uncertainty the results show that the ECMWF EPS is capable of predicting winter rainfall events in tropical West Africa with good accuracy, at least on regional spatial and synoptic time‐scales, which should encourage West African weather services to capitalize more on the valuable information provided by ensemble prediction systems during the dry season. Copyright © 2012 Royal Meteorological Society
Preparation of NiCrBSi‐WC brazed coating and its microstructure characteristics
Authors: Gao Li Xin , Liu Tao , Zhang Da Quan
Published: September 2012

WC–Ni composite coatings were developed by the powder cloth and the vacuum brazing technology. The wear resistance and the corrosion resistance of the brazed WC–Ni coatings were investigated. The peeling coating samples were prepared by using solder mask during brazing. The microstructures for the powder cloth and for the brazed coatings were characterized by scanning electron microscopy. The distribution of elements in the different area of the brazed coatings was determined by energy dispersive X‐ray maps. It shows that the segregation of chromium carbides occurs during brazing. Apart from penetrating into the interspaces of WC particles, the Ni‐based filler can also infiltrate and spread on the substrate surface. Copyright © 2012 John Wiley & Sons, Ltd.
In situmeasurement using FBGs of process‐induced strains during curing of thick glass/epoxy laminate plate: experimental results and numerical modelling
Authors: Nielsen Michael Wenani , Schmidt Jacob Wittrup , Hattel Jesper Henri , Andersen Tom Løgstrup , Markussen Christen Malte
Published: September 2012

For large composite structures, such as wind turbine blades, thick laminates are required to withstand large in‐service loads. During the manufacture of thick laminates, one of the challenges met is avoiding process‐induced shape distortions and residual stresses. In this paper, embedded fibre Bragg grating sensors are used to monitor process‐induced strains during vacuum infusion of a thick glass/epoxy laminate. The measured strains are compared with predictions from a cure hardening instantaneous linear elastic (CHILE) thermomechanical numerical model where different mechanical boundary conditions are employed. The accuracy of the CHILE model in predicting process‐induced internal strains, in what is essentially a viscoelastic boundary value problem, is investigated. A parametric study is furthermore performed to reveal the effect of increasing the laminate thickness. The numerical model predicts the experimental transverse strains well when a tied boundary condition at the tool/part interface is used and the tool thermal expansion is taken into account. However, the CHILE approach is shown to overestimate residual strains after demoulding because of the shortcomings of the model in considering viscoelastic effects. The process‐induced strain magnitude furthermore increases when the laminate thickness was increased, owing mainly to a decrease in through‐thickness internal transverse stresses. Copyright © 2012 John Wiley & Sons, Ltd.
Modeling, simulation and control of a wind turbine with a hydraulic transmission system
Authors: Skaare Bjørn , Hörnsten Bo , Nielsen Finn Gunnar
Published: September 2012

A complete mathematical model of a hydraulic transmission concept for use in wind turbines is presented. The hydraulic system transfers the power from the nacelle to ground level. The main focus has been to develop a model that takes into account the most important dynamics affecting the wind turbine and the hydraulic transmission system involved, such that the model can be used to analyze the dynamic feasibility of a hydraulic transmission concept. Further, dynamic analysis of a hydraulic transmission system for wind turbines is investigated. The nonlinear dynamic model is developed in MATLAB Simulink. Analytical calculation of natural periods of a linearized model corresponds well with simulations of the overall system.

A valve control system is proposed to reduce pressure and power fluctuations at operation both below and above the rated wind speed for the wind turbine. Further, a blade pitch control system based on an aerodynamic power estimator is proposed for operation above the rated wind speed.

System simulations for one case below and one case above the rated wind speed show that the dynamic response of the overall system is stable and that the wind turbine variables are within typical ranges for conventional variable speed wind turbines with mechanical transmission. Copyright © 2012 John Wiley & Sons, Ltd.
Ignoring ecological demands masks the real effect of urbanization: a case study of ground‐dwelling spiders along a rural–urban gradient in a lowland forest in Hungary
Authors: Horváth Roland , Magura Tibor , Tóthmérész Béla
Published: September 2012

We studied ground‐dwelling spiders along a rural–suburban–urban forest gradient representing increasing human disturbance using pitfall traps. We tested four known and two novel hypotheses: (1) increasing disturbance hypothesis (species richness is decreasing by disturbance); (2) matrix species hypothesis (the richness of open‐habitat species is increasing by disturbance); (3) opportunistic species hypothesis (the richness of generalist species is increasing by disturbance); and (4) habitat specialist hypothesis (the number of the forest specialist species is decreasing by disturbance). As a consequence of urbanization, urban forests become drier and more open; thus, according to the new hypotheses, the number of (5) xerophilous species and (6) light‐preferring species are increasing in the urban area. Our result did not support the increasing disturbance hypothesis, as the overall species richness increased from the rural sites to the urban ones. As predicted, the number of both the open‐habitat and the generalist species increased towards the urban sites. The number of forest specialist species was higher in the suburban area than in the rural and urban area. Both xerophilous and light‐preferring species were the most numerous in the urban area, supporting the xerophilous species and the light‐preferring species hypotheses. Canonical correspondence analysis showed that the forest specialist species associated with the rural sites with higher amounts of decaying woods and more herbs or with the suburban sites with higher cover of leaf litter and higher relative humidity. Two generalist species and one open‐habitat species were characteristic of urban sites with higher ground surface and air temperature.
ON THE EXISTENCE OF NONINNER AUTOMORPHISMS OF ORDER TWO IN FINITE 2-GROUPS
Authors: JAMALI A. R. , VISEH M.
Published: September 2012

In this paper we prove that every nonabelian finite 2-group with a cyclic commutator subgroup has a noninner automorphism of order two fixing either Φ(G) or Z(G) elementwise. This, together with a result of Peter Schmid on regular p-groups, extends our result to the class of nonabelian finite p-groups with a cyclic commutator subgroup.
Musculoskeletal Injuries Among Victims of the Battagram, Pakistan Earthquake in October 2005
Authors: Kaim Khani Ghulam Mustafa , Baig Akhtar , Humail Mujahid , Memon Manzoor , Quarashi M.A.
Published: September 2012

Objective

This study was conducted to assess the type, pattern, and severity of musculoskeletal injuries, as well as the type of simple orthopedic surgical procedures, that can be performed at the site of a disaster.

Methods

This was a cross-sectional study conducted in Battagram, located in the North West Frontier Province of Pakistan after the October 2005 earthquake. Researchers arrived in the affected area during the second week after the earthquake, and remained there for one week. During this period, patients were received from distant areas of the district. These patients were admitted to a tent hospital because the district headquarters hospital was completely damaged. Those requiring orthopedic surgical intervention or closed manipulation and plaster of paris casts were included in the study.

Results

Of 110 patients, 61 were female and 49 were male, and 140 bones were involved. In this series, 92 fractures were closed, while 48 were open. A total of 67.3% of the patients were <40 years of age. The tibia was involved in 32.1% of cases and the femur 16.4%. No cases of compartment syndrome were found. Wound debridement was performed in 35 cases. An external fixator was applied to 10 cases of open tibia fractures. Four humerus fractures and a fracture to the radius and ulna were fixed with the Rashnail method. One open femur fracture was repaired with external fixation. Pre- and post-operative antibiotics were administered in all cases. Thirty patients sustained injuries in addition to orthopedic trauma: 13 vertebral injuries, eight head injuries, six fractured ribs, three blunt injuries to the abdomen, and 10 significant soft tissues injuries without bony involvement.

Conclusions

After the earthquake in Battagram, young persons, especially females, were prone to orthopedic injuries, mainly involving the extremities. A comprehensive disaster plan would have helped to manage these emergencies, and further experience is needed for on-site surgical interventions.

Kaim KhaniGM, BaigA, HumailM, MemonM, QuarashiMA. Musculoskeletal injuries among victims of the Battagram, Pakistan earthquake in October 2005. Prehosp Disaster Med.2012;27(5):1-3.
Haline hurricane wake in the Amazon/Orinoco plume: AQUARIUS/SACD and SMOS observations
Authors: Grodsky Semyon A. , Reul Nicolas , Lagerloef Gary , Reverdin Gilles , Carton James A. , Chapron Bertrand , Quilfen Yves , Kudryavtsev Vladimir N. , Kao Hsun‐Ying
Published: September 2012

At its seasonal peak the Amazon/Orinoco plume covers a region of 106 km2in the western tropical Atlantic with more than 1 m of extra freshwater, creating a near‐surface barrier layer (BL) that inhibits mixing and warms the sea surface temperature (SST) to >29°C. Here new sea surface salinity (SSS) observations from the Aquarius/SACD and SMOS satellites help elucidate the ocean response to hurricane Katia, which crossed the plume in early fall, 2011. Its passage left a 1.5 psu high haline wake covering >105 km2 (in its impact on density, the equivalent of a 3.5°C cooling) due to mixing of the shallow BL. Destruction of this BL apparently decreased SST cooling in the plume, and thus preserved higher SST and evaporation than outside. Combined with SST, the new satellite SSS data provide a new and better tool to monitor the plume extent and quantify tropical cyclone upper ocean responses with important implications for forecasting.
The use of ionosondes in GPS ionospheric tomography at low latitudes
Authors: Chartier Alex T. , Smith Nathan D. , Mitchell Cathryn N. , Jackson David R. , Patilongo Percy J. C.
Published: September 2012

A new technique is presented for the incorporation of ionosonde observations into GPS ionospheric tomography. This approach greatly improves the vertical resolution of the images when using independent incoherent scatter radar observations as ground truth, addressing a traditional weakness of tomographic techniques. Ionosonde observations are used to set vertical basis functions adaptively within the inversion as well as providing electron density information for direct assimilation. The technique also improves slant total electron content (TEC) accuracy in the vicinity of the ionosonde. An experiment was performed in the equatorial region of South America as a 6‐day case study due to the availability of incoherent scatter and ionosonde data during this period. Preliminary results were validated with the Jicamarca incoherent scatter radar and independent GPS slant TEC observations. Using the incoherent scatter radar as ground truth for the vertical profile, the new technique reduces mean NmF2 error to −0.07 × 1011 electrons/m3 compared with 0.27 × 1011 electrons/m3 in a control run with no ionosonde data, while root‐mean square error is now 0.5 × 1011 electrons/m3 compared with 1.0 × 1011 electrons/m3 in the control. The new technique also results in 0.1 km mean error in hmF2, compared with −3.9 km in the control, while root‐mean square hmF2 error is around 40 km in both cases. Using independent slant TEC observations, the mean error is −0.36 TECU compared with 0.64 TECU in the control run, while root‐mean square error is 3.55 TECU down from 4.02 TECU, suggesting the new technique also improves TEC values.
Direct measurements of the seasonality of emission factors from savanna fires in northern Australia
Authors: Meyer C. P. , Cook G. D. , Reisen F. , Smith T. E. L. , Tattaris M. , Russell‐Smith J. , Maier S. W. , Yates C. P. , Wooster M. J.
Published: September 2012

Current good practice guidelines for national greenhouse gas inventories requires that seasonal variation in emission factors from savanna fires be considered when compiling national accounts. African studies concluded that the emission factor for methane decreases during the dry season principally due to curing of the fuels. However, available data from Australian tropical savannas shows no effect of seasonality on emission factors, consistent with observations that the fine fuels appear to cure fully soon after the start of the fire season. To test whether the seasonality in greenhouse gas emission factors reported for Africa also occurs in Australia, methane and nitrous oxide emission factors were measured in early and in late dry season fires in Western Arnhem Land, a region typical of much of the northern Australia savanna zone. We found no significant seasonality in methane emission factors, but there was substantial variation in emission factors associated with inter‐fire differences in vegetation and fuel. This variation could be explained almost completely by combustion efficiency. Nitrous oxide emission factors were not related to combustion efficiency but showed some variation across vegetation and fuel size class. Both methane and nitrous oxide emission factors were consistent with previous work in northern Australia and with some published values from Africa. The absence of a significant seasonal trend in emission factors indicates that savanna fire emissions in northern Australia can be managed by strategic prescribed burning.
The history of Mars' dynamo as revealed by modeling magnetic anomalies near Tyrrhenus Mons and Syrtis Major
Authors: Milbury C. , Schubert G. , Raymond C. A. , Smrekar S. E. , Langlais B.
Published: September 2012

The lack of magnetic anomalies within the major impact basins (Hellas, Argyre, and Isidis) has led many investigators to the conclusion that Mars' dynamo shut down prior to the time when these basins formed (∼4.0 Ga). We test this hypothesis by analyzing gravity and magnetic anomalies in the regions surrounding Tyrrhenus Mons and Syrtis Major, two volcanoes that were active during the late Noachian and Hesperian. We model magnetic anomalies that are associated with gravity anomalies and generally find that sources located below Noachian surface units tend to favor paleopoles near the equator and sources located below Hesperian surface features favor paleopoles near the geographical poles, suggesting polar wander during the Noachian‐Hesperian. Both paleopole clusters have positive and negative polarities, indicating reversals of the field during the Noachian and Hesperian. Magnetization of sources below Hesperian surfaces is evidence that the dynamo persisted beyond the formation of the major impact basins. The demagnetization associated with the volcanic construct of Syrtis Major implies dynamo cessation occurred while it was geologically active approximately 3.6 billion years ago. Timing of dynamo activity is fundamentally linked to Mars' climate via the stability of its atmosphere, and is coupled to the extent and duration of surface geologic activity. Thus, the dynamo history is key for understanding both when Mars was most geologically active and when it may have been most hospitable to life.