bluuebunny/crossref_metadata_2025 huggingface dataset:
Landslide susceptibility map of Slovenia at scale 1 : 250,000
Authors: Komac Marko , Ribičič Mihael
Published: April 2011

Based on the extensive landslide database that was compiled and standardised at the national level, and analyses of landslide spatial occurrence, a Landslide susceptibility map of Slovenia at scale 1 : 250,000 was completed. Altogether more than 6,600 landslides were included in the national database, of which roughly half are on known locations. Of 3,257 landslides with known location, random but representative 65 % were selected and used for the univariate statistical analyses (χ2 ) to analyse the landslide occurrence in relation to the spatio-temporal precondition factors (lithology, slope inclination, slope curvature, slope aspect, distance to geological boundaries, distance to structural elements, distance to surface waters, flowlength, and landcover type) and in relation to the triggering factors (maximum 24-h rainfall, average annual rainfall intensity, and peak ground acceleration). The analyses were conducted using GIS in raster format with the 25 × 25 m pixel size. Five groups of lithological units were defined, ranging from small to high landslide susceptibility. Also critical slopes for the landslide occurrence, other terrain properties and landcover types that are more susceptible to landsliding were defined. Among triggering factors critical rainfall and peak ground acceleration quantities were defined. These results were later used as a basis for the development of the weighted linear susceptibility model where several models with various factor weights variations based on previous research were developed. The rest of the landslide population (35 %) was used for the model validation. The results showed that relevant precondition spatio-temporal factors for landslide occurrence are (with their weight in linear model): lithology (0.3), slope inclination (0.25), landcover type (0.25), slope curvature (0.1), distance to structural elements (0.05), and slope aspect (0.05).
Jet Fuels
Authors: Dukek W. G.
Published: April 2011

Jet aircraft is a weight limited vehicle so a high premium is assigned to hydrocarbon fuels with a maximum gravimetric heat content or hydrogen‐to‐carbon ratio. Jet fuel specifications tend to be industry standards issued by ASTM. The global nature of aviation has mandated that jet fuel be closely controlled in every part of the world. The gas turbine power plant revolutionized aviation. Kerosene was the first fuel burned in Whittle's prototype jet engine. Aviation fuels are primarily blended from straight‐run distillates rather than cracked stocks because of limitations on olefins and aromatics. Distillation cuts must be closely controlled to yield a product that meets flash point on one hand and freezing point on the other, ie, a jet fuel requires a fraction of about 60°C initial boiling point and a final boiling point not exceeding 300°C. Additives are added to the final blend of fuel. Additives cover a large number of problems that could arise. Antiicing, agents, biocides, antistatic agents and others are discussed. Alternative fuels are now a world focus because of the carbon footprint of present fuels and the the instability of the crude supply. Fisher‐Tropsch Fuels (FT) and biofuels (HRJ) are discussed. Feedstocks for biofuels include camelina, jatropha, and algae. Life cycle assessments of alternative fuels are given. Flight trials have begun using alternative fuels including a U.S. Navy test with a supersonic aircraft (F/A‐18 Super Hornet).
Iodine and Iodine Compounds
Authors: Lauterbach Armin , Uber Gustavo
Published: April 2011

Iodine is a nonmetallic element belonging to the halogen family in Group 17 VII of the Periodic Table. Iodine is one of the scarcest of the nonmetallic elements in the total composition of the earth. Wherever iodine occurs, its quantities are generally exceedingly small and very sophisticated chemical methods are required to detect iodine. As found in nature, iodine has only one stable isotope. Several radioactive isotopes have been prepared and have found use as radiopharmaceuticals or tracers for medical imaging. Iodine is produced as a nitrate ore byproduct or from brines or seaweeds. Iodine is much safer to handle at ordinary temperatures than the other halogens because it is a solid at ambient temperatures and pressures. Current demand for iodine is for use in biocides, iodine salts, LCDs, synthetic fiber treatments, and x‐ray contrast media. Important inorganic and organic iodides and iodates are discussed
Papermaking Additives
Authors: Dulany Margaret A. , Batten George L. , Peck Michael C. , Farley Charles E.
Published: April 2011

In papermaking, chemicals can be added either to the pulp slurry prior to sheet formation, ie, internal or wet‐end addition, or to the resulting sheet after complete or partial drying, ie, surface or dry‐end addition. The method chosen depends on retention and the desired effect. Papermaking additives can be categorized either as process additives or functional additives. Procss additives are materials that improve the operation of the paper machine, such as retention and drainage aids, biocides, dispersants and defoamers. They are primarily added to the wet end of the paper machine. Functional additves are materials that enhance or alter specific properties of the paper product such as fillers, sizing agents, dyes, optical brighteners, wet‐and dry‐strength additives. They may be added internally or to the surface of the sheet. Environmental constraints on the paper industry have resulted in drastic processing changes, primarily because of the vast amounts of water used to produce paper. Numerous regional, state, local, and foreign national regulations exist concerning emissions to air and discharges to water and sludge. OSHA workplace regulations may have also altered the additive process and the choice of additives.
Rubidium and Rubidium Compounds
Authors: Wagner Frank S.
Published: April 2011

Rubidium is an alkali metal in Group 1(!A) of the Periodic Table. Its chemical and physical properties generally lie between those of potassium and cerium. There are no minerals in which rubidium is the predominant metallic element. Lepidolite and pollucite are the rubidium‐bearing minerals. The traditional processes used to recover rubidium from these minerals ores involve the extraction of mixed alkali alums from the ore via leaching. Rubidium compounds can also be separated from other alkali metal compounds by solvent extraction and ion exchange. Rubidium is generally listed as having a low degree of toxicity. Health risks are associated with rubidium compounds. The principal use for rubidium is in research. Rubidium isotopes are used in medical procedures and pharmaceuticals. It is also used in atomic clocks, ceramic applications, and in global positioning systems (GPS).
Biomaterials
Authors: Eisenbarth Eva
Published: April 2011

Biomaterials are materials used for medical applications. The interdisciplinary field of science, development and improvements of biomaterials, encompasses aspects of medicine, biology, nanotechnology, surface engineering, chemistry and materials science.

The applications of biomaterials range from contact lenses to artificial knee joints and dental implants. The steadily rising demand for tailor‐made biomaterials arises from an ageing population with very active lifestyles. The use of biomaterials may be of medical nature, for example for heart pacemakers, to improve the quality of life through the use of contact lenses and hip prostheses, or for aesthetical reason as breast implants. Biomaterial science is a broad multidisciplinary field that contributes to reducing human suffering and improves the health related quality of life.
Radio Frequency Identification Technology
Authors: Mccombie William , Welt Bruce A.
Published: April 2011

Radio‐frequency identification (RFID) is a method for automatic identification that relies on storing and retrieving data from transponder “tags.“ RFID systems require readers equipped with one or more antennas connected to back‐end computer systems. To date, RFID technology has been evaluated and implemented in a number of applications including supply chain tracking, animal identification, and toll collection and is expected to replace conventional barcode technologies. However, RFID has some drawbacks, including cost of implementation, reliability, performance, and potential for privacy misuse issues.
Ethylenesulfonic Acid Polymers
Authors: Breslow David S.
Published: April 2011

Ethylenesulfonic (or ethenesulfonic) acid, often incorrectly named vinylsulfonic acid, has been known for over 100 years. It is a readily available monomer that can be polymerized into a strongly acidic polyelectrolyte. Preparation and properties of the monomer, polymerization and properties of the polymers, and uses are discussed.
Vinylic Tellurides
Authors: Zeni Gilson , Menezes Paulo Henrique
Published: April 2011

The purpose of this chapter is to critically and comprehensively review the several methods described for the preparation of vinylic tellurides. Furthermore, this chapter will also discuss the vinylic telluride reactivity towards several different reaction conditions and the applicability of such transformations in organic synthesis.
Biological and Biochemical Aspects of Tellurium Derivatives
Authors: Detty Michael R.
Published: April 2011

Biological and biochemical studies of inorganic and organic complexes of tellurium are reviewed. Subject areas include the biosequestration and bioincorporation of tellurite and other inorganic tellurium compounds as well as tellurite‐resistant bacteria. The incorporation of tellurium into amino acids (tellurocysteine) and the formation of unnatural glutathione peroxidases and thioredoxin reductases incorporating tellurocysteine are also described. Low molecular weight organotellurium compounds that mimic glutathione peroxidase and the thioredoxin reductases are discussed as are inorganic and organic tellurium compounds that inhibit cysteine proteases and related enzymes. The interactions of P‐glycoprotein with organotellurium compounds to give stimulators and inhibitors of ATPase activity in the enzyme are described. The role of tellurium‐containing chromophores in the photodynamic therapy of cancer and the photodynamic inactivation of viral and bacterial pathogens is also reviewed. The binding modes of tellurium‐containing chromophores to DNA are also described.
An adaptive observer for joint estimation of states and parameters in both state and output equations
Authors: Li Xiuliang , Zhang Qinghua , Su Hongye
Published: April 2011

An adaptive observer is a recursive algorithm for joint state–parameter estimation of parameterized state‐space systems. Previous works on globally convergent adaptive observers consider unknown parameters either in state equations or in output equations, but not in both of them. In this paper, a new adaptive observer is designed for linear time‐varying systems with unknown parameters in both state and output equations. Its global convergence for simultaneous estimation of states and parameters is formally established under appropriate assumptions. A numerical example is presented to illustrate the performance of this adaptive observer. Copyright © 2011 John Wiley & Sons, Ltd.
Multiphase Model for Predicting the Elimination of Inclusions inside a Liquid‐Steel Ladle
Authors: Gardin Pascal , Gauthier Ségolène , Simonnet Marie , Lehmann Jean
Published: April 2011

In steelmaking, secondary metallurgy steps are crucial for the quality of the final product. Adjusting the steel‐grade composition and deoxidation of the liquid metal generate inclusions that can be harmful to downstream processes and to the product itself (occurrence of defects during rolling process). We present in this paper a numerical model to predict the kinetics of the elimination of inclusions by entrapment by the different phases present in the ladle (slag, bubbles injected in the liquid metal, top layer of gas). We show results for a 3D configuration, and a comparison with industrial data is performed.
A Novel Manufacturing Route for Fabrication of Topologically‐Ordered Porous Magnesium Scaffolds
Authors: Nguyen Thanh L. , Staiger Mark P. , Dias George J. , Woodfield Timothy B. F.
Published: April 2011

The use of porous metal foams as biomaterial scaffolds has been widely adopted; however, many of these porous structures are manufactured with pore architectures that are inherently random. This makes structural optimization for a specific purpose challenging. Scaffolds containing ordered pore architectures can be fabricated to meet design criteria, such as porosity, stiffness, and volume fraction. Mg and its alloys offer potential as a new class of degradable metallic orthopedic biomaterials. In comparison with current metallic orthopedic implant materials, Mg offers advantages such as, closer‐to‐bone stiffness and biodegradability, thereby eliminating the need for a second surgery to remove hardware. Currently there are few methods described in literature to manufacture ordered porous Mg. The aim of this study was to determine the resolution of a novel indirect solid free‐form fabrication (SFF) process for producing topologically ordered Mg (TOPM) structures. The multi‐step method involved the printing of an SFF mould, NaCl infiltration, and liquid Mg casting techniques. Using a range of characterization methods, we demonstrated that the selected structures were manufactured with a high level of accuracy. Differences in dimensions from CAD models to Mg scaffolds ranged from 2.5% to a maximum of 8.33%. Similarly, there was a maximum of 6.1% reduction in porosity in Mg scaffolds compared with initial design. Meanwhile, with surface roughness of 10.17 ± 1.75 µm, there was an average of 70% increase in surface area. This study demonstrates a simple, reliable, and safe route to manufacture TOPM scaffolds for potential application in medical device design.
Semimetal/Semiconductor Nanocomposites for Thermoelectrics
Authors: Lu Hong , Burke Peter G. , Gossard Arthur C. , Zeng Gehong , Ramu Ashok T. , Bahk Je‐Hyeong , Bowers John E.
Published: April 2011

In this work, we present research on semimetal‐semiconductor nanocomposites grown by molecular beam epitaxy (MBE) for thermoelectric applications. We study several different III‐V semiconductors embedded with semimetallic rare earth‐group V (RE‐V) compounds, but focus is given here to ErSb:InxGa1‐xSb as a promising p‐type thermoelectric material. Nano­structures of RE‐V compounds are formed and embedded within the III‐V semiconductor matrix. By codoping the nanocomposites with the appropriate dopants, both n‐type and p‐type materials have been made for thermoelectric applications. The thermoelectric properties have been engineered for enhanced thermoelectric device performance. Segmented thermoelectric power generator modules using 50 μm thick Er‐containing nanocomposites have been fabricated and measured. Research on different rare earth elements for thermoelectrics is discussed.
Zeolitic Materials with Hierarchical Porous Structures
Authors: Lopez‐Orozco Sofia , Inayat Amer , Schwab Andreas , Selvam Thangaraj , Schwieger Wilhelm
Published: April 2011

During the past several years, different kinds of hierarchical structured zeolitic materials have been synthesized due to their highly attractive properties, such as superior mass/heat transfer characteristics, lower restriction of the diffusion of reactants in the mesopores, and low pressure drop. Our contribution provides general information regarding types and preparation methods of hierarchical zeolitic materials and their relative advantages and disadvantages. Thereafter, recent advances in the preparation and characterization of hierarchical zeolitic structures within the crystallites by post‐synthetic treatment methods, such as dealumination or desilication; and structured devices by in situ and ex situ zeolite coatings on open‐cellular ceramic foams as (non‐reactive as well as reactive) supports are highlighted. Specific advantages of using hierarchical zeolitic catalysts/structures in selected catalytic reactions, such as benzene to phenol (BTOP) and methanol to olefins (MTO) are presented.
Flexible Nano‐felts of Carbide‐Derived Carbon with Ultra‐high Power Handling Capability
Authors: Presser Volker , Zhang Lifeng , Niu Jun Jie , McDonough John , Perez Carlos , Fong Hao , Gogotsi Yury
Published: April 2011

Nano‐fibrous felts (nano‐felts) of carbide‐derived carbon (CDC) have been developed from the precursor of electrospun titanium carbide (TiC) nano‐felts. Conformal transformation of TiC into CDC conserves main features of the precursor including the high interconnectivity and structural integrity; the developed TiC‐CDC nano‐felts are mechanically flexible/resilient, and can be used as electrode material for supercapacitor application without the addition of any binder. After synthesis through chlorination of the precursor at 600 °C, the TiC‐CDC nano‐fibers show an average pore size of ∼1nm, a high specific surface area of 1390 m2/g; and the nano‐fibers have graphitic carbon ribbons embedded in a highly disordered carbon matrix. Graphitic carbon is preserved from the precursor nano‐fibers where a few graphene layers surround TiC nanocrystallites. Electrochemical measurements show a high gravimetric capacitance of 110 F/g in aqueous electrolyte (1 M H2SO4) and 65 F/g in organic electrolyte (1.5 M TEA‐BF4 in acetonitrile). Because of the unique microstructure of TiC‐CDC nano‐felts, a fade of the capacitance of merely 50% at a high scan rate of 5 V/s is observed. A fade of just 15% is observed for nano‐felt film electrodes tested in 1 M H2 SO4 at 1 V/s, resulting in a high gravimetric capacitance of 94 F/g. Such a high rate performance is only known for graphene or carbon‐onion based supercapacitors, whereas binders have to be used for the fabrication of those supercapacitors.
Nitrile‐Substituted QA Derivatives: New Acceptor Materials for Solution‐Processable Organic Bulk Heterojunction Solar Cells
Authors: Zhou Tianlei , Jia Tao , Kang Bonan , Li Fenghong , Fahlman Mats , Wang Yue
Published: April 2011

The development of non‐fullerene‐based electron acceptors (especially organic molecules with sufficient absorption property within the solar spectrum region) for bulk‐heterojunction (BHJ) organic solar cells (OSCs) is an important issue for the achievement of high photoconversion efficiency. In this contribution, a new class of organic acceptors di‐cyan substituted quinacridone derivatives (DCN‐nCQA, n = 4, 6 and 8) for BHJ solar cells was designed and synthesized. DCN‐nCQA molecules possess facile synthesis, solution processability, visible and near‐IR light absorption and relatively stable characteristics. The DCN‐8CQA molecule exhibited a proper LUMO energy level (–4.1 eV), small bandgap (1.8 eV) and moderate electron mobility (10−4 cm2 V−1 S−1), suggesting that this molecule is an ideal acceptor material for the classical donor material regio‐regular poly (3‐hexylthiophene) (P3HT). A photovoltaic device with a structure of [ITO/PEDOT:PSS/P3HT:DCN‐8CQA/LiF/Al] displayed a power conversion efficiency of 1.57% and a fill factor of 57% under 100 mW cm−2 AM 1.5G simulated solar illumination. The DCN‐nCQA molecules showed remarkable absorption in the region from 650 to 700 nm, where P3HT has a weak absorption promoting overlap with the solar spectrum and potentially improving the performance of the solar cell.
A role for partially protected areas on coral reefs: maintaining fish diversity?
Authors: Tyler Elizabeth H. M. , manica Andrea , Jiddawi Narriman , Speight Martin R.
Published: April 2011

Completely banning fishing from coral reefs is now accepted to have significant benefits for marine biodiversity and in many cases, fisheries. However, the benefits of regulating fishing on coral reefs, by restricting the methods used, or the total amount of fishing, are less well understood, even though such regulations are much more likely to be supported by fishermen.

This study assesses whether banning illegal, destructive fishing methods and reducing the numbers of fishermen visiting from outside an area benefits a coral reef fishery, despite unregulated fishing by local fishermen using non‐destructive methods.

The abundance, biomass, mean length, and species richness of nine commercially important fish families are compared across ten independent patch reefs inside and outside the 470 km2 Menai Bay Conservation Area in Zanzibar, Tanzania.

Even after taking into account the effect of differences in habitat and the distance between reefs, 61% (±19.7%) more fish species were found in regulated than unregulated reefs. Fish abundance, biomass, and length were not affected, suggesting that banning destructive fishing may improve biodiversity, but that further regulations may be required to improve fish stocks.Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and Antibacterial Activity of Various Substituted Oxadiazole Derivatives
Authors: Kaur Hemlata , Kumar Sunil , Verma R. S. , Garg Amit , Saxena K. K. , Lata Suman , Kumar Ashok
Published: April 2011

Some new 2‐(2‐(4(4‐substitutedbenzoyl‐2‐methylphenoxy)acetyl)‐N‐(2‐substitutedphenyl) hydrazinecarbothioamides (4a–4j) and (4‐((5‐(2‐substitutedphenylamino)‐1,3,4‐oxadiazol‐2‐yl)methoxy)‐3‐substitutedphenyl)(phenyl)methanones (5a–5j) have been synthesized from 2‐(4‐(3‐substitutedbenzoyl)‐2‐methylphenoxy)acetohydrazides (3a, 3b). These newly synthesized compounds (4a–4j and 5a–5j) were characterized by elemental and spectral (IR, 1H‐NMR and MS) analysis. All the synthesized compounds have been screened for their antibacterial activity against both types of Gram negative and Gram positive bacteria. The most potent antibacterial compound of this series was compound 5i which has the low MIC 3.75–0.9375 µg/mL value. Both minimal inhibitory concentration (MIC) and inhibition zones were determined in order to monitor the efficacy of the synthesized compounds. Certain compounds inhibit bacterial growth with low MIC (µg/mL) value.
Influence of MIL‐101 Doping by Ionic Clusters on Hydrogen Storage Performance up to 1900 Bar
Authors: Klyamkin Semen N. , Berdonosova Elena A. , Kogan Ekaterina V. , Kovalenko Konstantin A. , Dybtsev Danil N. , Fedin Vladimir P.
Published: April 2011

Ultra‐high‐pressure hydrogen‐storage performance (up to 1900 bar) was investigated for mesoporous chromium terephthalate MIL‐101 and its inclusion compounds containing ionic clusters [Re4S4F12]4− and [SiW11O39]7− within the porous framework. The maximum specific hydrogen uptake values (total) for MIL‐101 are 12.3 (at 81) and 7.2 wt. % (at 293 K). Such unique measurement conditions allowed us to identify the density of the absorbed hydrogen directly from the excess sorption isotherm curves. The corresponding density values were found to be almost comparable at low temperature, but significantly different at ambient temperature, which indicated an increase of more than double in the number of hydrogen binding sites in the case of the inclusion compounds with rhenium clusters.
Understanding consumers' brand‐induced food taste perception: A comparison of ‘brand familiarity’ – and ‘consumer value – brand symbolism (in)congruity’ – accounts
Authors: Paasovaara Rami , Luomala Harri T. , Pohjanheimo Terhi , Sandell Mari
Published: April 2011

Past research has shown that familiar brands can boost consumers' food taste experiences. On the other hand, more recent evidence suggests that the (in)congruity between consumer values and brand symbolism can affect the food taste perception. This study is the first one to integrate these two accounts into one single conceptual framework and to empirically evaluate their relative roles in explaining consumers' brand‐induced taste perception. Two experiments involving taste trials (blind vs brand‐cued sensory evaluation) were conducted. The first experiment analysed the brand familiarity effect, whereas the second experiment addressed also the taste perception of yogurts with differing brand symbolism amongst food consumers with distinct value orientations to find support for the (in)congruity effects. This research implies that congruity is not responsible for enhancing consumers' taste perception beyond the level that is produced by the brand familiarity. In contrast, the incongruity effect appears capable of neutralising the brand familiarity effect. Therefore, these two explanations may operate independently. More generally, this study speaks for the importance of incorporating consumer value – brand symbolism incongruity mechanism into food consumption studies; even owners' of strong food brands cannot trust the ability of their brands to boost a consumer's taste experience if there is no correspondence between his or her central values and brand symbolism. Thus, an objectively better taste is not necessarily decisive; satisfactory sensory quality can suffice if it is coupled with imaginative and daring brand marketing that delivers unique emotional and functional benefits for well‐defined food consumer target segments. Copyright © 2011 John Wiley & Sons, Ltd.
Cellular Localisation of Antitumoral 6‐Alkyl Thymoquinones Revealed by an Alkyne–Azide Click Reaction and the Streptavidin–Biotin System
Authors: Effenberger‐Neidnicht Katharina , Breyer Sandra , Mahal Katharina , Diestel Randi , Sasse Florenz , Schobert Rainer
Published: April 2011

The subcellular distribution and accumulation of thymoquinone 1, a natural anticancer agent, has hitherto been unknown. We prepared 6‐(dec‐9‐ynyl)thymoquinone 3, an alkyne‐labelled derivative with anticancer activity similar to that of its parent compound 1. Alkyne 3 was seen, after a Huisgen‐type click reaction with 3‐azido‐7‐hydroxycoumarin, to accumulate in distinct compartments of the nuclei of PtK2 potoroo kidney cells, and in adjoining regions that were stained with an antibody specific for the Golgi apparatus. In contrast, a biotinlabelled thymoquinone 4 seemed to accumulate across the entire cell nucleus upon visualisation with streptavidin; but this was less easily traceable because of co‐staining of other structures such as mitochondria. In conclusion, for small drug‐like molecules, visualisation by alkyne–azide cycloaddition seems to be superior to conventional visualisation by the biotin–streptavidin system.
“Crowned” Univalent Indium Complexes as Donors? Experimental and Computational Insights on the Valence Isomers of EE′X4 Species
Authors: Cooper Benjamin F. T. , Hamaed Hiyam , Friedl Warren W. , Stinchcombe Michael R. , Schurko Robert W. , Macdonald Charles L. B.
Published: April 2011

The use of the univalent indium reagent [In([18]crown‐6)][OTf] as a donor is investigated by its reactions with acceptors including InX3 (X=Cl, Br, I). The donor–acceptor complexes of the form [X([18]crown‐6)InInX3] obtained in this manner represent the first new isomeric form of indium(II) halides identified for at least five decades. The formation of such complexes appears to be particularly favorable and they are isolated as products in many reactions involving low‐valent indium, a halide source, and [18]crown‐6. A convenient solution‐phase synthesis of In[ECl4] salts is reported. This facile and direct syntheses of In[ECl4] (E=Al, Ga, In) salts allows for the in situ preparation and isolation of crown‐ether complexes of the form [In([18]crown‐6)][ECl4], whose existence had been postulated but never confirmed. Solution‐phase and solid‐state NMR experiments reveal that these compounds can exist as either donor–acceptor complexes or ionic salts, depending on the phase of the system, the nature of the solvent employed, and the identity of the metalate anion involved. Similar investigations into the effect of a smaller crown ether allow for the isolations of salts containing the cation [In([15]crown‐5)]+. Computational investigations into the nature of the crowned univalent indium donor fragments, and on the donor–acceptor complexes produced, demonstrate the influence of anionic substituents on the reactivity of lone pair of electrons of the InI center. Natural bond orbital (NBO) analysis of donor–acceptor models shows that the composition of the EE bond MO should provide the ability to predict which models should form stable complexes.
Tubular or Subsurface Morphology of Octabutoxyphthalocyanine upon Self‐Assembly in Polymer Matrices: Effect of the Casting Solvent
Authors: Islam Molla R. , Sundararajan Pudupadi R.
Published: April 2011

Spontaneous phase‐separated, controlled aggregate structures of photo‐ and electroactive molecules in polymer matrices are of interest for device fabrication. We show that the self‐assembly of octabutoxyphthalocyanine (Pc) in polymer matrices leads to tubular morphology of Pc when the film is prepared with tetrachloroethane (TCE) and subsurface droplet morphology with chloroform. The same morphology is seen with both bisphenol A polycarbonate (BPAPC) and poly(methyl methacrylate) (PMMA) as the matrix. The subsurface morphology results from the rapid association of Pc in the polymer matrix, as the film forms. With the tubular morphology in the films prepared with TCE, percolation threshold is reached with a concentration of Pc as low as 3 % (wt) in the polymer. Such phase‐separated self‐assembly occurs, without any annealing of the films. Even in the absence of the polymer, Pc crystallized from TCE also shows tubular morphology, whereas it exhibits a columnar morphology with chloroform. X‐ray diffraction of Pc crystallized from either solvent shows the columnar stacking of the Pc molecules. However, the morphology is tubular when TCE is used. We attribute the difference in the morphology to the higher viscosity of TCE and the diffusion‐limited growth, which causes the tubular morphology, whereas the instantaneous self‐assembly in less‐viscous chloroform leads to droplets. The solvent effect observed here could be used to tailor the morphology of such photoconductive molecules in polymer matrices.
Response of surface processes to climatic change in the dunefields and Loess Plateau of North China during the late Quaternary
Authors: Lu Huayu , Mason Joseph A. , Stevens Thomas , Zhou Yali , Yi Shuangwen , Miao Xiaodong
Published: April 2011

This paper draws on recent optically stimulated luminescence (OSL) dating to evaluate the long‐held assumption that dust accumulation rates in the Loess Plateau and the extent of active aeolian sand in the dunefields to the north have varied together over time, because both are controlled by the strength of the Asian monsoons and also possibly because the dunefields are proximal loess sources. The results show there is little evidence that high rates of loess accumulation coincided with well‐dated episodes of extensive dune activity in the Mu Us, Otindag, and Horqin dunefields, at 11–8 ka and 1–0 ka. Explanations for the apparent lack of coupling include local variation in the trapping of dust and post‐depositional preservation of the loess and dune sediments, in response to varying local environmental conditions. In addition, a substantial portion of the loess may be transported directly from source areas where dust emission has somewhat different climatic and geomorphic controls than aeolian sand activity within the dunefields. The results of this study cast doubt on the use of loess accumulation rate as a palaeoclimatic proxy at millennial timescale. The dunefield and loess stratigraphic records are interpreted as primarily recording changes in effective moisture at a local scale, but the timing of late Quaternary dune activity, along with a variety of other evidence, indicates that moisture changes in many of the drylands of northern China may not be in phase with precipitation in core regions of the Asian monsoons. Copyright © 2011 John Wiley & Sons, Ltd.
Variance risk premiums and predictive power of alternative forward variances in the corn market
Authors: Wang Zhiguang , Fausti Scott W. , Qasmi Bashir A.
Published: April 2011

We propose a fear index for corn using the variance swap rate synthesized from out‐of‐the‐money call and put options as a measure of implied variance. We find negative and time‐varying variance risk premiums (realized variance minus implied variance) in the corn market from 1987 to 2009. Our results contrast with Egelkraut, Garcia, and Sherrick (2007), but are in line with the findings of Simon (2002). We conclude that our synthesized model‐free implied variance estimation procedure contains superior information about future realized variance relative to traditional model‐dependent estimating procedures: the implied variance model by Black (1976) and the seasonal GARCH(1, 1) forecasted variance model. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark 32:587–608, 2012
Molecular Recognition of Amino Acids, Peptides, and Proteins by Cucurbit[n]uril Receptors
Authors: Urbach Adam R. , Ramalingam Vijayakumar
Published: April 2011

At the forefront of the endeavor to understand and manipulate living systems is the design and study of receptors that bind with high affinity and selectivity to specific amino acids, peptides, and proteins. Cucurbit[n]urils are among the most promising class of synthetic receptors for these targets due to their high affinities and selectivities in aqueous media and to the unique combination of electrostatic and hydrophobic interactions that govern binding. The fundamental supramolecular chemistry in this area has been explored in depth, and novel, useful applications are beginning to emerge.
Negotiating a flexible work arrangement: How women navigate the influence of power and organizational context
Authors: Greenberg Danna , Landry Elaine M.
Published: April 2011

Prior work‐life research has highlighted that while organizations may be introducing more work‐life policies, organizational members are not necessarily using these policies. Empirical research is needed that focuses on the individual and provides insight into who is taking advantage of these policies and how they go about negotiating access. In this study, we explore this issue as we investigate the behavioral dynamics that underlie women's experiences negotiating a flexible work arrangement. Focusing on the individual, we examine the influence that perceptions of power and organizational work‐life support have on flexible work arrangement negotiations. The results of our research indicate that both macro level factors such as perceived work life support and micro level factors such as perceptions of power affect both the process and outcomes of these negotiations. We explore the implications these findings have for work‐life and negotiation research. Copyright © 2011 John Wiley & Sons, Ltd.
Incorporation of carbon nanotubes in a silica HPLC column to enhance the chromatographic separation of peptides: Theoretical and practical aspects
Authors: André Claire , Aljhani Rania , Gharbi Tijani , Guillaume Yves C.
Published: April 2011

The retention mechanism of a series of peptides on a single‐wall carbon nanotube (SWCNT) stationary phase inside an HPLC column was investigated over a wide range of mobile phase compositions. While the similar size C18 column exhibited an efficiency of 11.5 μm, the SWCNT column increased the efficiency, i.e. 7.10 μm at a flow rate of 0.8 mL/min, and significantly affected the separation quality of the peptides. The values of enthalpy (ΔH) and entropy (ΔS*) of transfer of the peptides from the mobile to the SWCNT stationary phase were determined. The method studied each factor, i.e. ACN fraction x in the ACN/water mixture and column temperature. The changes in retention factor, ΔH and ΔS* as a function of the ACN fraction in the mobile phase were examined. These variations are explained using the organization of ACN in clusters in the ACN/water mixture and on the steric and electronic forces implied in the retention process. The information obtained in this work makes this SWCNT stationary phase useful for peptide research and demonstrated the role of ACN to improve the separation quality.
Mesh‐independent matrix cracking and delamination modeling in laminated composites
Authors: Iarve Endel V. , Gurvich Mark R. , Mollenhauer David H. , Rose Cheryl A. , Dávila Carlos G.
Published: April 2011

The initiation and evolution of transverse matrix cracks and delaminations are predicted within a mesh‐independent cracking (MIC) framework. MIC is a regularized extended finite element method (x‐FEM) that allows the insertion of cracks in directions that are independent of the mesh orientation. The Heaviside step function that is typically used to introduce a displacement discontinuity across a crack surface is replaced by a continuous function approximated by using the original displacement shape functions. Such regularization allows the preservation of the Gaussian integration schema regardless of the enrichment required to model cracking in an arbitrary direction. The interaction between plies is anchored on the integration point distribution, which remains constant through the entire simulation. Initiation and propagation of delaminations between plies as well as intra‐ply MIC opening is implemented by using a mixed‐mode cohesive formulation in a fully three‐dimensional model that includes residual thermal stresses. The validity of the proposed methodology was tested against a variety of problems ranging from simple evolution of delamination from existing transverse cracks to strength predictions of complex laminates withouttextita priori knowledge of damage location or initiation. Good agreement with conventional numerical solutions and/or experimental data was observed in all the problems considered. Published 2011. This article is a US Government work and is in the public domain in the USA.
Identification of the major constituents in Xuebijing injection by HPLC‐ESI‐MS
Authors: Huang Hao , Ji Lanxin , Song Shengyou , Wang Jing , Wei Na , Jiang Min , Bai Gang , Luo Guoan
Published: April 2011

Introduction – Xuebijing injection (XBJ) is a traditional Chinese herbal prescription widely used in the treatment of sepsis. This is the first report concerning the identification of XBJ constituents. In addition, to evaluate XBJ's quality, partial least square discrimination analysis (PLS‐DA) was performed on chemical fingerprint data.

Objective – Establish an LC‐MS method to identify the components in XBJ for the purpose of quality control.

Methodology – Compounds were separated by HPLC using a C18 column and gradient elution of acetonitrile–methanol (60:40, v/v) and water–acetic acid (100 : 0.5, v/v) in 80 min. HPLC equipped with diode array detector (DAD) coupled with time‐of‐flight (TOF) tandem mass spectrometry and HPLC electrospray ionisation (ESI) multi‐stage tandem ion‐trap mass spectrometry (IT‐MSn) method was developed to analyse XBJ's major components. Both positive and negative ionisation modes were employed.

Results – Twenty‐one compounds including amino acids, phenolic acids, flavonoid glycoside, terpene glycoside and phthalide were identified or tentatively characterised. Their retention times, UV and MS spectra were compared with those of authentic compounds or literature data. The score plot of PLS‐DA clearly revealed variations among samples produced in different commercial batches.

Conclusion – The analytical method developed is highly effective for the discrimination and quality control of XBJ.
Photoluminescence of epoxy/clay nanocomposites
Authors: Mondragón Margarita , Cortes Miguel Angel , Arias Eduardo , Falcony Ciro , Zelaya‐Angel Orlando
Published: April 2011

Polymer nanocomposites of an epoxy resin with natural montmorillonite (MMT), organically modified montmorillonite(OMMT), and halloysite nanotubes(HNTs) were prepared by the solvent casting method. Photoluminescence (PL) measurements showed that the epoxy nanocomposites with OMMT and HNTs give rise to a red‐shift of the emission band associated to bisphenol groups and to well resolved emission spectra, attributable to coplanar packing of the polymer chains in the excited states. A significant PL quenching in all the nanocomposites was observed, which depended on type and clay concentration. Atomic force microscopy (AFM) images showed a greater penetration of the epoxy resin only into the OMMT and HNT agglomerates. A relationship between the PL behavior and both the extent of confinement of polymer chains in clays agglomerates and the changes in the formation of trapping sites produced from hydroxyl groups could be revealed by AFM images and Fourier transform infrared spectroscopy (FTIR) studies. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Effect of processing conditions on the development of morphological features of banded or nonbanded spherulites of poly(3‐hydroxybutyrate) (PHB) and polylactic acid (PLLA) blends
Authors: El‐Hadi Ahmed Mohamed
Published: April 2011

Two semicrystalline poly(3‐hydroxybutyrate) (PHB) and polylactic acid (PLLA) blends with and without poly(vinyl acetate) (PVAc) were prepared by dissolving different ratios in hot chloroform at 50 °C to obtain promising alternative biodegradable materials for eliminating plastic waste. The miscibility, crystallization, melting behavior and vibration modes of the prepared samples were characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM), Fourier transform infrared spectroscopy (FTIR), and wide angle X‐ray diffraction (WAXD) techniques. DSC analysis showed that only one crystallization temperature for blends with PVAc (single homogeneous phase) and two crystallization temperatures for blends without PVAc (immiscible blends) were obtained. The POM results indicated that the morphological structures of B381, B551, and B831 samples consist of two types of spherulites (fibrils and banded) which created at different crystallization temperatures. The irrelevant interaction between PHB and PLLA structures was detected from FTIR spectra. The addition of PVAc caused an obvious decrease in the peak position of the carboxyl group CO from 1752 to 1724 cm−1 due to dipole‐dipole interactions. WAXD indicated that the lattice parameters are changed in blends with PVAc and unchanged without PVAc. Our results indicated that, the PVAc can be used as compatibilizer and improved the compatibility between PHB and PLLA. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Studies of implanted boron emitters for solar cell applications
Authors: Pawlak B. J. , Janssens T. , Singh S. , Kuzma‐Filipek I. , Robbelein J. , Posthuma N. E. , Poortmans J. , Cristiano F. , Bazizi E. M.
Published: April 2011

B implanted emitters are investigated in the back junction cell configuration and their material properties are tested in double side implanted Si wafers. B has been implanted at 5 keV at various dose conditions varying from 1 × 1014 up to 3 × 1015 at./cm2 and activated at 1000°C for 10 min. N‐type 8 × 8 cm2 mono‐crystalline cells are fabricated and measured. Both fill factor and efficiency increase for high‐B doses. However, at 1015 at./cm2 B dose the Voc drops, which is in agreement with lifetime degradation in the wafer. Defect evolution simulations of BnIm clusters formation is correlated with lifetime degradation. Copyright © 2011 John Wiley & Sons, Ltd.
Plasma Induced Multiwalled Carbon Nanotube Grafted with 2‐Vinylpyridine for Preconcentration of Pb(II) from Aqueous Solutions
Authors: Ren Xuemei , Shao Dadong , Zhao Guixia , Sheng Guodong , Hu Ju , Yang Shitong , Wang Xiangke
Published: April 2011

Multiwalled carbon nanotubes (MWCNTs) are grafted with 2‐vinylpyridine (VP) by using N2 plasma technique. The VP grafted MWCNTs (MWCNT‐g‐VP) are characterized by using X‐ray diffraction, X‐ray photoelectron spectroscopy, and thermo‐gravimetric analysis‐differential thermal analysis. The application of MWCNTs and MWCNT‐g‐VP in the removal of Pb(II) from large volumes of wastewater is investigated under ambient conditions. The results indicate that the grafted VP improved MWCNT sorption capacity obviously in the removal of Pb(II). The VP molecules grafted on the surfaces of MWCNT‐g‐VP can prevent the entanglement of MWCNT‐g‐VP and provide more functional groups, promoting the sorption of Pb(II) onto MWCNT‐g‐VP. According to the results simulated by Langmuir model, the maximum sorption capacities (Csmax) of Pb(II) are ∼15.9 mg·g−1 on MWCNTs and ∼37.0 mg·g−1 on MWCNT‐g‐VP at pH = 6.0. The variation of separation factors indicates that the sorption of Pb(II) on MWCNTs and MWCNT‐g‐VP is favorable. The relatively high sorption capacity shows that MWCNT‐g‐VP is a suitable material for the preconcentration and immobilization of heavy metal ions from large volumes of aqueous solutions in environmental pollution management.

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A life cycle framework for the investigation of environmentally benign nanoparticles and products
Authors: Theis Thomas L. , Bakshi Bhavik R. , Durham Delcie , Fthenakis Vasilis M. , Gutowski Timothy G. , Isaacs Jacqueline A. , Seager Thomas , Wiesner Mark R.
Published: April 2011

While significant advances in our understanding of the behavior of engineered nanoparticles in the environment continue, there remains a need to engage the nanoparticle research community directly in the development and evaluation of environmentally benign nanoparticles to ensure that nanomaterial‐based industries emerge as tools for sustainability rather than environmental liabilities. Current research efforts aimed at understanding the environmental implications of nanotechnology emphasize existing groups of nanoparticles and products already in commercial distribution. While this is clearly necessary, this approach fails to identify and address the many tradeoffs associated with product performance and environmental quality. We believe this to be a critical gap in the ongoing exploration of nanostructured materials and their properties and applications. We posit that a number of issues are not being holistically addressed, including resource availability and allocation, manufacturing energy requirements and embodied energy, material efficiency, environmental properties of nanomaterials and nanoproducts, and waste generation. An interdisciplinary approach to research, based on the life cycle paradigm and devoted to the identification, investigation, synthesis, testing, and analysis of groups of new, more environmentally conscious nanoparticles is needed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light confinement in e‐beam evaporated thin film polycrystalline silicon solar cells
Authors: Soderstrom T. , Wang Q. , Omaki K. , Kunz O. , Ong D. , Varlamov S.
Published: April 2011

Polycrystalline Si thin‐film (poly‐Si) solar cells need effective light‐trapping to compensate for the moderate absorption. Recent developments in the poly‐Si cell technology focus on film fabrication by e‐beam evaporation due to its manufacturing benefits, such as a very high deposition rate above 15 nm/s and inline compatible process. However, evaporated poly‐Si cells exhibit limited compatibility with textured glass. In this Letter, the coupling of the light in the absorber layer is enhanced by introducing a rough interface at the back of the solar cells. This increases the conversion efficiency from 6% to 7.1% for, respectively, planar and back textured interface with current density of 26.6 mA/cm2 for only 3.6 μm absorber thickness. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)