bluuebunny/crossref_metadata_2025 huggingface dataset:
Public Services and International Trade Liberalization
Authors: Choudhury Barnali
Published: November 2012

Does public service liberalization pose a threat to gender and human rights? Traditionally considered essential services provided by a state to its citizens, public services are often viewed as public goods which embody social values. Subjecting them to market ideology thus raises concerns that the intrinsic social nature of these services will be negated. Moreover, as those most likely to be reliant on public services, public service liberalization may also further marginalize women. Nevertheless, states continue to increasingly liberalize public services. Barnali Choudhury explores the implications of public service liberalization. Using primarily a legal approach, but drawing from case studies, empirical research and gender theories, she examines whether liberalization under the General Agreement on Trade in Services and other liberalization vehicles such as preferential trade and investment agreements compromise human rights and gender objectives.
Constructing International Security
Authors: Benson Brett V.
Published: November 2012

Constructing International Security helps policy makers and students recognize effective third-party strategies for balancing deterrence and restraint in security relationships. Brett V. Benson shows that there are systematic differences among types of security commitments. Understanding these commitments is key, because commitments, such as formal military alliances and extended deterrence threats, form the basis of international security order. Benson argues that sometimes the optimal commitment conditions military assistance on specific hostile actions the adversary might take. At other times, he finds, it is best to be ambiguous by leaving an ally and adversary uncertain about whether the third party will intervene. Such uncertainty transfers risk to the ally, thereby reducing the ally's motivation to behave too aggressively. The choice of security commitment depends on how well defenders can observe hostilities leading to war and on their evaluations of dispute settlements, their ally's security and the relative strength of the defender.
Counterflows
Authors: Shtern Vladimir
Published: November 2012

This book discusses the physical mechanisms that drive counterflows, examining how they emerge, develop, become double and multiple counterflows and comprise both global and local circulations. Counterflows play an important role in nature and technology. A natural example is the Gulf Stream and the opposite flow in the ocean depths. Technological applications include hydrocyclones, vortex tubes and vortex combustors. These elongated counterflows are wildly turbulent but survive intense mixing, a seeming paradox. Local counterflows, whose spatial extent is small compared with that of surrounding flows, occur behind bluff bodies and in swirling streams. The latter are often referred to as vortex breakdown bubbles, which occur in tornadoes and above delta wings. Most scale counterflows are cosmic bipolar jets. Most miniature counterflows occur in capillary menisci of electrosprays and fuel atomisers.
Large-Scale Solar Power Systems
Authors: Gevorkian Peter
Published: November 2012

This book is a comprehensive discussion and economic analysis of large-scale solar power systems, specifically referencing critical issues related to design construction and financing. The book provides practical design, installation, and financing guidelines for large-scale commercial and industrial solar power projects. Engineering design and construction methodologies as well as economic analysis provide a step-by-step walk-through of all aspects of solar power systems. Design methodologies outline the specific requirements of solar and electrical design and construction documentation in meticulous detail, which can readily be applied to ground mount, roof mount, building integrated (BIPV), and carport-type solar power projects. In view of the importance of solar power systems as a viable present and future energy resource, the book includes a dedicated chapter on smart grid transmission and large-scale energy storage systems.
Labour Law
Authors: Collins Hugh , Ewing K. D. , McColgan Aileen
Published: November 2012

Building on their successful cases and materials book, Collins, Ewing and McColgan present an entirely restructured and freshly written new textbook on employment law. Comprehensive and engaging, it combines detailed analysis and commentary on the law with short contextual extracts to fully equip the labour law student. Carefully balancing clear exposition of legal principles with critical and scholarly analysis, this is the definitive textbook on the subject written by the UK's foremost employment law scholars. The book's 20-part structure maps logically onto either a full or half module employment law course. Chapter introductions and conclusions and an uncluttered text design carefully guide the student through the material. Innovative case studies show the law 'in action' and discussion of the globalised workplace gives the work a contemporary feel. Put simply, this is required reading for all students of the subject.
Submesoscale eddies near the Kuril Straits: Asymmetric generation of clockwise and counterclockwise eddies by barotropic tidal flow
Authors: Nakamura T. , Matthews J. P. , Awaji T. , Mitsudera H.
Published: November 2012

High spatial resolution thermal infrared (TIR) images derived by the LANDSAT Thematic Mapper (TM) sensors show the presence of numerous small‐scale eddies near the Kuril Islands. As the diameters of these eddies range from around 2 to 30 km (i.e., submesoscale), they are much smaller than the eddies previously reported in this region (several tens to some hundreds of kilometers in diameter). Our simulations suggest that small‐scale eddies similar to those observed in the satellite data are generated by diurnal barotropic tides. The eddy generation is well defined from Etorofu/Friza to the Onnekotan Straits, and it is caused by the effects of coastal boundaries and the stretching of water columns, which lead to eddy growth even after eddies have left the coast. We find that the counterclockwise eddies are generally larger in number and size and stronger in vorticity and surface height than the clockwise eddies in both the gradient and cyclostrophic wind balance regimes. The possible causes of such asymmetry are (1) the effect of planetary‐vorticity tube stretching, which can be significant even when the final relative vorticity becomes much greater than planetary vorticity and (2) asymmetric advection by the rotating tidal flow, which advects counterclockwise eddies offshore but clockwise eddies onshore. These eddies induce strong stirring with a maximum apparent diffusivity of 108 cm2 s−1. The numbers, properties, and mixing effects of eddies vary greatly with the spring‐neap cycle.
Subaqueous “yardangs”: Analogs for aeolian yardang evolution
Authors: Carling Paul A.
Published: November 2012

Landforms, morphologically similar to aeolian yardangs but formed by erosion of bedrock by currents on an estuarine rock platform, are described for the first time. The geometries of the “yardangs” are described and related to semi‐lemniscate shapes that minimize hydraulic drag. The processes of bedrock erosion by the reversing sediment‐laden tidal currents are described, and a semi‐quantitative model for landform evolution is proposed. The model casts doubt on the “simple” role of the maximum in the two‐dimensional vertical suspended sediment flux distribution and the consequent distribution of potential kinetic energy flux in the process of shaping the rock wall facing the ebb flow. Rather, although the kinetic energy flux increases away from the bed, the sediment becomes finer and abrasion likely is insignificant compared with coarse sand abrasion lower in the profile. In addition, the vertical distribution of sediment flux is mediated by topographic forcing which raises the elevation at which bed load intersects the yardang prow. Consequent erosion leads to ebb‐facing caprock collapse and yardang shortening. In contrast, the role of ebb‐flow separation is paramount in mediating the abrasion process that molds the rock surface facing the flood flow. The length of yardangs is the least conservative dimension, reducing through time more rapidly than the height and width. Width is the more conservative dimension which implies that once the caprock is destroyed, scour over the obstacle is significant in reducing body height, more so than scour of the flanks which reduces width. The importance of vertical fissures in instigating the final breakdown of smaller yardangs and their extinction is noted. Similarities to aeolian yardang geometries and formation principles and processes are noted, as are the differences. The model has implications for aeolian yardang models generally.
Three‐phase compositional modeling of CO2 injection by higher‐order finite element methods with CPA equation of state for aqueous phase
Authors: Moortgat Joachim , Li Zhidong , Firoozabadi Abbas
Published: November 2012

Most simulators for subsurface flow of water, gas, and oil phases use empirical correlations, such as Henry's law, for the CO2 composition in the aqueous phase, and equations of state (EOS) that do not represent the polar interactions between CO2and water. Widely used simulators are also based on lowest‐order finite difference methods and suffer from numerical dispersion and grid sensitivity. They may not capture the viscous and gravitational fingering that can negatively affect hydrocarbon (HC) recovery, or aid carbon sequestration in aquifers. We present a three‐phase compositional model based on higher‐order finite element methods and incorporate rigorous and efficient three‐phase‐split computations for either three HC phases or water‐oil‐gas systems. For HC phases, we use the Peng‐Robinson EOS. We allow solubility of CO2in water and adopt a new cubic‐plus‐association (CPA) EOS, which accounts for cross association between H2O and CO2 molecules, and association between H2O molecules. The CPA‐EOS is highly accurate over a broad range of pressures and temperatures. The main novelty of this work is the formulation of a reservoir simulator with new EOS‐based unique three‐phase‐split computations, which satisfy both the equalities of fugacities in all three phases and the global minimum of Gibbs free energy. We provide five examples that demonstrate twice the convergence rate of our method compared with a finite difference approach, and compare with experimental data and other simulators. The examples consider gravitational fingering during CO2sequestration in aquifers, viscous fingering in water‐alternating‐gas injection, and full compositional modeling of three HC phases.
Decadal changes in dissolved inorganic carbon in the Pacific Ocean
Authors: Kouketsu Shinya , Murata Akihiko , Doi Toshimasa
Published: November 2012

Using high‐quality data sets obtained about a decade apart, we examined the changes of dissolved inorganic carbon in the Pacific Ocean, separating anthropogenic and natural CO2. Observations along three transoceanic sections along 47°N, 179°E, and 17°S showed both decadal increases (>20 µmol kg–1) and decreases (<−20 µmol kg–1) of anthropogenic CO2 in thermocline waters. As a result, the decadal‐scale storage of anthropogenic CO2 north of 40°N in the North Pacific was close to ±0 mol m–2 a–1, except in the western subarctic Pacific. In contrast, in subtropical regions of both hemispheres, we found an increasing trend of >10 µmol kg–1 in oceanic uptake of anthropogenic CO2, reflecting accumulation in mode waters. Along 17°S, increases of anthropogenic CO2 were >20 µmol kg–1, larger than expected from increases of anthropogenic CO2 in the atmosphere. The annual water‐column inventories of anthropogenic CO2 changes calculated in 20° longitudinal or 10° latitudinal bands throughout the Pacific Ocean revealed relatively high values (>0.7 mol m–2 a–1) in the subtropical regions of both hemispheres and low values in the tropical Pacific. This distribution pattern is similar to previous estimates for the Anthropocene, implying that the redistribution processes of anthropogenic CO2 have not changed on a basin scale over the last decade. We estimated the total anthropogenic and natural CO2 storage in the Pacific Ocean to be 8.4 ± 0.5 and 0.6 ± 0.4 Pg carbon decade–1, respectively.
Waveform modeling of shear wave splitting from anisotropic models in Iceland
Authors: Fu Yuanyuan V. , Li Aibing , Ito Garrett , Hung Shu‐Huei
Published: November 2012

No quantitative model of seismic anisotropy beneath Iceland has yet explained the observed shear wave splitting results in Iceland. In this study we explore the structure of mantle seismic anisotropy associated with plume ridge interaction beneath Iceland by modeling synthetic waveforms using a pseudo‐spectral method. First, predicted SKS waveforms are shown to produce shear wave splitting results for two anisotropic layers that are in generally agreement with analytic solutions. Next, simple models in which anisotropy are imposed at different depths and geographic regions around Iceland are used to examine different hypothesized effects of plume‐ridge interaction. The model that is designed to represent crystallographic fabric due to mantle deformation associated with lithosphere spreading in western Iceland and along‐axis, channeled asthenospheric flow in eastern Iceland can predict the distinct shear wave splitting observations on the east and west sides of the island. Last, we analyze geodynamic models that simulate 3‐D mantle flow and evolution of mineral fabric. The predicted fast directions of shear wave splitting from the models with realistic spreading rate (10 km/Myr) and broad range of plume viscosities are consistent with the observations in central and eastern Iceland. However, because these models are symmetric about the ridge, none of them can predict the observed shear wave splitting results in western Iceland.
Using a global aerosol model adjoint to unravel the footprint of spatially‐distributed emissions on cloud droplet number and cloud albedo
Authors: Karydis V. A. , Capps S. L. , Moore R. H. , Russell A. G. , Henze D. K. , Nenes A.
Published: November 2012

The adjoints of the GEOS‐Chem Chemical Transport Model and a comprehensive cloud droplet parameterization are coupled to study the sensitivity of cloud droplet number concentration (Nd) over US regions and Central Europe to global emissions of anthropogenic fine mode aerosol precursors. Simulations reveal that the Nd over the midwestern and southeastern US is mostly sensitive to SO2 emissions during August, and to NH3 emissions during February. Over the western US, Nd is mostly sensitivity to SO2 and primary organic aerosol emissions. In Central Europe, Nd is most sensitive to NH3 and NOx emissions. As expected, local emissions strongly affect Nd; long‐range transport, however, is also important for the western US and Europe. Emissions changes projected for the year 2050 are estimated to have the largest impacts on cloud albedo andNd over Central Europe during August (42% and 82% change, respectively) and western US during February (12% and 36.5% change, respectively).
Cassini UVIS observations of Titan nightglow spectra
Authors: Ajello Joseph M. , West Robert A. , Gustin Jacques , Larsen Kristopher , Stewart A. Ian F. , Esposito Larry W. , McClintock William E. , Holsclaw Gregory M. , Bradley E. Todd
Published: November 2012

In this paper we present the first nightside EUV and FUV airglow limb spectra of Titan showing molecular emissions. The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed photon emissions of Titan's day and night limb‐airglow and disk‐airglow on multiple occasions, including during an eclipse observation. The 71 airglow observations analyzed in this paper show EUV (600–1150 Å) and FUV (1150–1900 Å) atomic multiplet lines and band emissions arising from either photoelectron induced fluorescence and solar photo‐fragmentation of molecular nitrogen (N2) or excitation by magnetosphere plasma. The altitude of the peak UV emissions on the limb during daylight occurred inside the thermosphere at the altitude of the topside ionosphere (near 1000 km altitude). However, at night on the limb, a subset of emission features, much weaker in intensity, arise in the atmosphere with two different geometries. First, there is a twilight photoelectron‐excited glow that persists with solar depression angle up to 25–30 degrees past the terminator, until the solar XUV shadow height passes the altitude of the topside ionosphere (1000–1200 km). The UV twilight glow spectrum is similar to the dayglow but weaker in intensity. Second, beyond 120° solar zenith angle, when the upper atmosphere of Titan is in total XUV darkness, there is indication of weak and sporadic nightside UV airglow emissions excited by magnetosphere plasma collisions with ambient thermosphere gas, with similar N2 excited features as above in the daylight or twilight glow over an extended altitude range.
In situ fragmentation and rock particle sorting on arid hills
Authors: McGrath Gavan S. , Nie Zhengyao , Dyskin Arcady , Byrd Tia , Jenner Rowan , Holbeche Georgina , Hinz Christoph
Published: November 2012

Transport processes are often proposed to explain the sorting of rock particles on arid hillslopes, where mean rock particle size often decreases in the downslope direction. Here we show that in situ fragmentation of rock particles can also produce similar patterns. A total of 93,414 rock particles were digitized from 880 photographs of the surface of three mesa hills in the Great Sandy Desert, Australia. Rock particles were characterized by the projected Feret's diameter and circularity. Distance from the duricrust cap was found to be a more robust explanatory variable for diameter than the local hillslope gradient. Mean diameter decreased exponentially downslope, while the fractional area covered by rock particles decreased linearly. Rock particle diameters were distributed lognormally, with both the location and scale parameters decreasing approximately linearly downslope. Rock particle circularity distributions showed little change; only a slight shift in the mode to more circular particles was noted to occur downslope. A dynamic fragmentation model was used to assess whether in situ weathering alone could reproduce the observed downslope fining of diameters. Modeled and observed size distributions agreed well and both displayed a preferential loss of relatively large rock particles and an apparent approach to a terminal size distribution of the rocks downslope. We show this is consistent with a size effect in material strength, where large rocks are more susceptible to fatigue failure under stress than smaller rocks. In situ fragmentation therefore produces qualitatively similar patterns to those that would be expected to arise from selective transport.
Integrated stratigraphy of the Paleocene‐Eocene thermal maximum in the New Jersey Coastal Plain: Toward understanding the effects of global warming in a shelf environment
Authors: Stassen Peter , Thomas Ellen , Speijer Robert P.
Published: November 2012

In the New Jersey Coastal Plain, a silty to clayey sedimentary unit (the Marlboro Formation) represents deposition during the Paleocene‐Eocene thermal maximum (PETM). This interval is remarkably different from the glauconitic sands and silts of the underlying Paleocene Vincentown and overlying Eocene Manasquan Formation. We integrate new and published stable isotope, biostratigraphic, lithostratigraphic and ecostratigraphic records, constructing a detailed time frame for the PETM along a depth gradient at core sites Clayton, Wilson Lake, Ancora and Bass River (updip to downdip). The onset of the PETM, marked by the base of the carbon isotope excursion (CIE), is within the gradual transition from glauconitic silty sands to silty clay, and represented fully at the updip sites (Wilson Lake and Clayton). The CIE “core” interval is expanded at the updip sites, but truncated. The CIE “core” is complete at the Bass River and Ancora sites, where the early part of the recovery is present (most complete at Ancora). The extent to which the PETM is expressed in the sediments is highly variable between sites, with a significant unconformity at the base of the overlying lower Eocene sediments. Our regional correlation framework provides an improved age model, allowing better understanding of the progression of environmental changes during the PETM. High‐resolution benthic foraminiferal data document the change from a sediment‐starved shelf setting to a tropical, river‐dominated mud‐belt system during the PETM, probably due to intensification of the hydrologic cycle. The excellent preservation of foraminifera during the PETM and the lack of severe benthic extinction suggest there was no extreme ocean acidification in shelf settings.
The impact of wettability and connectivity on relative permeability in carbonates: A pore network modeling analysis
Authors: Gharbi Oussama , Blunt Martin J.
Published: November 2012

We use pore network modeling to study the impact of wettability and connectivity on waterflood relative permeability for a set of six carbonate samples. Four quarry samples are studied, Indiana, Portland, Guiting, and Mount Gambier, along with two subsurface samples obtained from a deep saline Middle Eastern aquifer. The pore space is imaged in three dimensions using X‐ray microtomography at a resolution of a few microns. The images are segmented into pore and solid, and a topologically representative network of pores and throats is extracted from these images. We then simulate quasi‐static displacement in the networks. We represent mixed‐wet behavior by varying the oil‐wet fraction of the pore space. The relative permeability is strongly dependent on both the wettability and the average coordination number of the network. We show that traditional measures of wettability based on the point where the relative permeability curves cross are not reliable. Good agreement is found between our calculations and measurements of relative permeability on carbonates in the literature. This work helps establish a library of benchmark samples for multiphase flow and transport computations. The implications of the results for field‐scale displacement mechanisms are discussed, and the efficiency of waterflooding as an oil recovery process in carbonate reservoirs is assessed depending on the wettability and pore space connectivity.
Nuclear factor κB down-regulates human UDP-glucuronosyltransferase 1A1: a novel mechanism involved in inflammation-associated hyperbilirubinaemia
Authors: Shiu Tzu-Yue , Huang Tien-Yu , Huang Shih-Ming , Shih Yu-Lueng , Chu Heng-Cheng , Chang Wei-Kuo , Hsieh Tsai-Yuan
Published: November 2012

Jaundice or hyperbilirubinaemia is a common complication of sepsis. UGT1A1 (UDP-glucuronosyltransferase 1A1) is a critical gene for bilirubin metabolism and irinotecan detoxification. However, the molecular pathogenesis of hyperbilirubinaemia during inflammation needs to be further clarified. Human hepatic UGT1A1 expression was analysed by RT (reverse transcription)–PCR, qRT-PCR (quantitative real-time PCR) and Western blotting in response to LPS (lipopolysaccharide) stimulation. Transcription regulatory elements in the upstream promoter region of the human UGT1A1 gene were determined using EMSA (electrophoretic mobility-shift assay) and ChIP (chromatin immunoprecipitation). The important role of the transcription regulatory element was examined using a luciferase assay, and was determined by qRT-PCR using a transcription factor activation inhibitor. LPS down-regulated the UGT1A1 mRNA expression in human hepatoma cell lines. A newly identified NF-κB (nuclear factor κB)-binding site was located on the upstream promoter region (−725/−716) of the human UGT1A1 gene. LPS-induced NF-κB activation and specific binding to the NF-κB-binding site can suppress human UGT1A1 promoter activity and human UGT1A1 expression. We demonstrated that LPS mediates the suppression of human UGT1A1 expression through specific binding of NF-κB to this newly identified NF-κB-binding site in the upstream promoter of the human UGT1A1 gene. The present study may partly explain the molecular pathogenesis of inflammation-associated hyperbilirubinaemia.
Angiotensin-converting enzyme inhibition curbs tyrosine nitration of mitochondrial proteins in the renal cortex during the early stage of diabetes mellitus in rats
Authors: Ishii Naohito , Carmines Pamela K. , Yokoba Masanori , Imaizumi Hiroyuki , Ichikawa Tsuyoshi , Ikenagasa Hideki , Kodera Yoshio , Oh-Ishi Masamichi , Aoki Yoshikazu , Maeda Tadakazu , Takenaka Tsuneo , Katagiri Masato
Published: November 2012

Experiments were performed to evaluate the hypothesis that ACE (angiotensin-converting enzyme) inhibition (enalapril) suppresses 3-NT (3-nitrotyrosine) production in the renal cortex during the early stage of Type 1 DM (diabetes mellitus) in the rat. Enalapril was administered chronically for 2 weeks to subsets of STZ (streptozotocin)-induced DM and vehicle-treated sham rats. O2− (superoxide anion) and NOx (nitrate+nitrite) levels were measured in the media bathing renal cortical slices after 90 min incubation in vitro. SOD (superoxide dismutase) activity and 3-NT content were measured in the renal cortex homogenate. Renal cortical nitrated protein was identified by proteomic analysis. Renal cortical production of O2− and 3-NT was increased in DM rats; however, enalapril suppressed these changes. DM rats also exhibited elevated renal cortical NOx production and SOD activity, and these changes were magnified by enalapril treatment. 2-DE (two-dimensional gel electrophoresis)-based Western blotting revealed more than 20 spots with positive 3-NT immunoreactivity in the renal cortex of DM rats. Enalapril treatment blunted the DM-induced increase in tyrosine nitration of three proteins ACO2, GDH1 and MMSDH (aconitase 2, glutamate dehydrogenase 1 and methylmalonate-semialdehyde dehydrogenase), each of which resides in mitochondria. These data are consistent with enalapril preventing DM-induced tyrosine nitration of mitochondrial proteins by a mechanism involving suppression of oxidant production and enhancement of antioxidant capacity, including SOD activation.
Revisiting literature observations on photodarkening in Yb3+doped fiber considering the possible presence of Tm impurities
Authors: Peretti Romain , Gonnet Cédric , Jurdyc Anne-Marie
Published: November 2012

Ytterbium (Yb) doped fiber lasers are known to be affected by the creation of color centers during lasing (so-called photodarkening (PD)). In a previous work, this defect creation was investigated from a spectroscopic point of view, showing the presence of traces (ppb) of thulium (Tm) in the Yb doped fiber. It was shown that Tm has a strong impact on the defect creation process involved in PD. In this paper, we compare the results from the literature with our Tm hypothesis, without finding any contradiction. Moreover, this hypothesis can be an explanation for the discrepancies in the literature.
Blow-up criteria of solutions for a modified two-component hyperelastic rod system
Authors: Guo Zhengguang , Jin Liangbing , Ni Lidiao
Published: November 2012

We consider a modified two-component rod system, which is a generalization of the two-component Camassa-Holm system to allow a dependence on the average density as well as on the pointwise density. Sufficient conditions on the initial data to guarantee finite time singularities for strong solutions are established on the real line and the periodic case.
Vlasov moment flows and geodesics on the Jacobi group
Authors: Gay-Balmaz François , Tronci Cesare
Published: November 2012

By using the moment algebra of the Vlasov kinetic equation, we characterize the integrable Bloch-Iserles system on symmetric matrices [Bloch, A. M., Brînzănescu, V., Iserles, A., Marsden, J. E., and Ratiu, T. S., “A class of integrable flows on the space of symmetric matrices,” Commun. Math. Phys. 290, 399–435 (2009)]10.1007/s00220-009-0849-6 as a geodesic flow on the Jacobi group \documentclass[12pt]{minimal}\begin{document}${\rm Jac}(\mathbb {R}^{2n})={\rm Sp}(\mathbb {R}^{2n})\,\circledS \,{\rm H}(\mathbb {R}^{2n})$\end{document} Jac (R2n)= Sp (R2n)ⓈH(R2n). We analyze the corresponding Lie-Poisson structure by presenting a momentum map, which both untangles the bracket structure and produces particle-type solutions that are inherited from the Vlasov-like interpretation. Moreover, we show how the Vlasov moments associated to Bloch-Iserles dynamics correspond to particular subgroup inclusions into a group central extension (first discovered by Ismagilov, Losik, and Michor [“A 2-cocycle on a group of symplectomorphisms,” Mosc. Math. J. 6, 307–315 (2006)]), which in turn underlies Vlasov kinetic theory. In the most general case of Bloch-Iserles dynamics, a generalization of the Jacobi group also emerges naturally.
Thermal diffusivity and mechanical properties of polymer matrix composites
Authors: Weidenfeller Bernd , Anhalt Mathias , Kirchberg Stefan
Published: November 2012

Polypropylene–iron-silicon (FeSi) composites with spherical particles and filler content from 0 vol. % to 70 vol. % are prepared by kneading and injection molding. Modulus, crystallinity, and thermal diffusivity of samples are characterized with dynamic mechanical analyzer, differential scanning calorimeter, and laser flash method. Modulus as well as thermal diffusivity of the composites increase with filler fraction while crystallinity is not significantly affected. Measurement values of thermal diffusivity are close to the lower bound of the theoretical Hashin-Shtrikman model. A model interconnectivity shows a poor conductive network of particles. From measurement values of thermal diffusivity, the mean free path length of phonons in the amorphous and crystalline structure of the polymer and in the FeSi particles is estimated to be 0.155 nm, 0.450 nm, and 0.120 nm, respectively. Additionally, the free mean path length of the temperature conduction connected with the electrons in the FeSi particles together with the mean free path in the particle-polymer interface was estimated. The free mean path is approximately 5.5 nm and decreases to 2.5 nm with increasing filler fraction, which is a result of the increasing area of polymer-particle interfaces. A linear dependence of thermal diffusivity with the square root of the modulus independent on the measurement temperature in the range from 300 K to 415 K was found.
Exchange bias properties of [Co/CoO]n multilayers
Authors: Öztürk M. , Sınır E. , Demirci E. , Erkovan M. , Öztürk O. , Akdoğan N.
Published: November 2012

In this study, the exchange bias properties of four polycrystalline multilayer stack samples of antiferromagnetic (AF) CoO and ferromagnetic (FM) Co in the form of [CoO/Co]n with n = 1, 2, 3, and 5 are reported. The samples were grown on top of Si (001) substrates by using magnetron sputtering method. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were used to determine the structural properties of the samples. XPS measurements of cobalt oxide layer revealed the coexistence of different phases in cobalt oxide as CoO and Co3O4, the latter of which lowers the blocking temperature. The blocking temperature is also affected by the finite size scaling effects observed in AF layers. In-plane ferromagnetic resonance (FMR) measurements revealed uniaxial in-plane magnetic anisotropy for the samples. Low temperature vibrating sample magnetometer measurements provided exchange bias with a stepwise character. Observed steps are believed to be due to magnetization reversals of individual FM layers with varying thicknesses, each of which is pinned through two interfaces from above and below with two AFM layers, except the uppermost FM Co layer with a single AFM neighbor.
Analytical estimates of free Brownian diffusion times in corrugated narrow channels
Authors: Bosi Leone , Ghosh Pulak K. , Marchesoni Fabio
Published: November 2012

The diffusion of a suspended Brownian particle along a sinusoidally corrugated narrow channel is investigated to assess the validity of two competing analytical schemes, both based on effective one-dimensional kinetic equations, one continuous (entropic channel scheme) and the other discrete (random walker scheme). For narrow pores, the characteristic diffusion time scale is represented by the mean first exit time out of a channel compartment. Such a diffusion time has been analytically calculated in both approximate schemes; the two analytical results coincide in leading order and are in excellent agreement with the simulation data.
Subdiffusion of proteins and oligomers on membranes
Authors: Lepzelter David , Zaman Muhammad
Published: November 2012

Diffusion of proteins on lipid membranes plays a central role in cell signaling processes. From a mathematical perspective, most membrane diffusion processes are explained by the Saffman-Delbrück theory. However, recent studies have suggested a major limitation in the theoretical framework, the lack of complexity in the modeled lipid membrane. Lipid domains (sometimes termed membrane rafts) are known to slow protein diffusion, but there have been no quantitative theoretical examinations of how much diffusion is slowed in a general case. We provide an overall theoretical framework for confined-domain (“corralled”) diffusion. Further, there have been multiple apparent contradictions of the basic conclusions of Saffman and Delbrück, each involving cases in which a single protein or an oligomer has multiple transmembrane regions passing through a lipid phase barrier. We present a set of corrections to the Saffman-Delbrück theory to account for these experimental observations. Our corrections are able to provide a quantitative explanation of numerous cellular signaling processes that have been considered beyond the scope of the Saffman-Delbrück theory, and may be extendable to other forms of subdiffusion.
Phonon limited transport in graphene nanoribbon field effect transistors using full three dimensional quantum mechanical simulation
Authors: Akhavan Nima Dehdashti , Jolley Gregory , Umana-Membreno Gilberto A. , Antoszewski Jarek , Faraone Lorenzo
Published: November 2012

This paper present a study of carrier transport in graphene nanoribbon (GNR) transistors using three-dimensional quantum mechanical simulations based on a real-space approach of the non-equilibrium Green's function formalism in the ballistic and dissipative limit. The carrier transport parameters are determined in the presence of electron-phonon scattering, and its influence on carrier mobility including both optical phonons (OPs) and acoustic phonons (APs). The performances of GNR field effect transistors (GNRFETs) are investigated in detail considering the third nearest neighbour tight-binding approximation. The low-field mobility is extracted in the presence of AP and OP as a function of nanoribbon width and length, from which the diffusive/ballistic limit of operation in GNRFETs is determined.
Effects of DyHx and Dy2O3 powder addition on magnetic and microstructural properties of Nd-Fe-B sintered magnets
Authors: Bae Kyoung-Hoon , Kim Tae-Hoon , Lee Seong-Rae , Namkung Seok , Jang Tae-Suk
Published: November 2012

The magnetic and microstructural properties of (Nd27.68Dy4.89)-Febal.B1.0M2.4 (wt. %, M = Cu, Al, Co, and Nb) sintered magnets doped with Dy2O3 and DyHx powders were studied. The coercivity of the DyHx-doped magnet improved, with no change in the remanence. Well-developed core-shell microstructures were seen in the DyHx-doped magnet, as compared to the case of the Dy2O3-doped magnet. Diffusion of Dy was enhanced in the DyHx-doped magnet, probably because dissolution of hydrogen in Nd2Fe14B increased the lattice parameter. The (00L) grain alignment in the DyHx-doped magnet was also improved.
Temperature dependence of cavity-polariton energies in ZnO and CuCl microcavities
Authors: Kawase Toshiki , Miyazaki Kenichi , Kim Daegwi , Nakayama Masaaki
Published: November 2012

We have investigated the temperature dependence of the cavity-polariton energies in ZnO and CuCl microcavities with HfO2/SiO2 distributed Bragg reflectors. From angle-resolved reflectance spectra at 10 K, we experimentally confirmed the cavity-polariton dispersions. The experimental dispersions were analyzed with a phenomenological Hamiltonian for the exciton-photon strong coupling. Furthermore, the temperature dependence of the angle-resolved reflectance spectra was measured. We analyzed the experiment results of the temperature dependence of the energies of the cavity polaritons on the basis of the phenomenological Hamiltonian, taking account of Varshni's law to treat the temperature dependence of the band-gap energy in a bulk crystal. Note that the temperature dependence of the exciton energies in a CuCl bulk crystal is extraordinary, which is in reverse to that in a ZnO bulk crystal. We have revealed that the temperature dependence of the energies of the cavity polaritons, which deviates from that of the exciton in the bulk crystal, considerably depends on the relative fractions of the exciton and cavity-photon components in the cavity polaritons.
Lithiation-induced tensile stress and surface cracking in silicon thin film anode for rechargeable lithium battery
Authors: Liu Ping , Sridhar N. , Zhang Yong-Wei
Published: November 2012

Cracks are found at the surface of silicon thin film anodes during lithiation-delithiation cycles in rechargeable lithium battery. However, whether crack formation occurs during lithiation or delithiation is still controversial. Using both an analytical model and a more complete finite element model, we show that a transition from compressive to tensile stress occurs at the silicon thin film surface during the lithiation process itself. This stress transition arises from the large volume expansion, plastic deformation, and slow charging rate which results in a sharp interface separating the lithiated and unlithiated zones. Our analysis further shows this tensile stress is sufficient to cause cracking of the lithiated thin film surface, suggesting cracks observed experimentally in silicon thin films are first generated during the lithiation step, rather than the delithiation step.
Effect of capacitive coupling in a miniature inductively coupled plasma source
Authors: Takao Yoshinori , Eriguchi Koji , Ono Kouichi
Published: November 2012

Two-dimensional axisymmetric particle-in-cell simulations with a Monte Carlo collision algorithm (PIC-MCC) have been conducted to investigate the effect of capacitive coupling in a miniature inductively coupled plasma source (mICP) by using two models: an inductive model and a hybrid model. The mICP is 3 mm in radius and 6 mm in height with a three-turn planar coil, where argon plasma is sustained. In the inductive model, the coil is assumed to be electrostatically shielded, and thus the discharge is purely inductive coupling. In the hybrid model, we assume that the different turns of the coil act like electrodes in capacitive discharge to include the effect of capacitive coupling. The voltage applied to these electrodes decreases linearly from the powered end of the coil towards the grounded end. The numerical analysis has been performed for rf frequencies in the range of 100–1000 MHz, and the power absorbed by the plasma in the range of 5–50 mW at a fixed pressure of 500 mTorr. The PIC-MCC results show that potential oscillations at the plasma-dielectric interface are not negligible, and thus the major component of the absorbed power is caused by the axial motion of electrons in the hybrid model, although almost all of the power absorption is due to the azimuthal motion of electrons in the inductive model. The effect of capacitive coupling is more significant at lower rf frequencies and at higher absorbed powers under the calculation conditions examined. Moreover, much less coil currents are required in the hybrid model.
An eight-dimensional quantum mechanical Hamiltonian for X + YCZ3 system and its applications to H + CH4 reaction
Authors: Liu Rui , Xiong Hongwei , Yang Minghui
Published: November 2012

An eight-dimensional quantum mechanical Hamiltonian has been proposed based on Palma and Clary's model in which the non-reacting CZ3 group keeps a C3v symmetry in the X + YCZ3 ↔ XY + CZ3 reaction J. Palma and D. C. Clary [J. Chem. Phys. 112, 1859 (2000)10.1063/1.480749]. By transforming the original Cartesian coordinate system (x, s) into a scaled polar coordinate system (q, γ), the vibrational Hamiltonian of CZ3 group is expressed in a simple form with a clear physical picture. This Hamiltonian is used to investigate the H + CH4 → H2 + CH3 reaction on the Jordan-Gilbert potential energy surface. The total reaction probabilities are calculated for the initial ground state, and umbrella, bending, symmetric, and asymmetric stretching excited states of CH4 with total angular momentum J = 0. The integral cross sections for the reaction are also studied for these initial vibrational states with a centrifugal-sudden approximation. The total integral cross sections for the asymmetric stretching vibrational excited state are in good agreement with the experimental observations. The results also showed the difference of dynamical behavior between reactions from symmetric and asymmetric stretching excited states. The thermal rate constants are calculated for the temperature range T = 250–2000 K and compared with the experimental and other theoretical results.
SiNx-induced intermixing in AlInGaAs/InP quantum well through interdiffusion of group III atoms
Authors: Lee Ko-Hsin , Thomas Kevin , Gocalinska Agnieszka , Manganaro Marina , Pelucchi Emanuele , Peters Frank H. , Corbett Brian
Published: November 2012

We analyze the composition profiles within intermixed and non-intermixed AlInGaAs-based multiple quantum wells structures by secondary ion mass spectrometry and observe that the band gap blue shift is mainly attributed to the interdiffusion of In and Ga atoms between the quantum wells and the barriers. Based on these results, several AlInGaAs-based single quantum well (SQW) structures with various compressive strain (CS) levels were grown and their photoluminescence spectra were investigated after the intermixing process involving the encapsulation of thin SiNx dielectric films on the surface followed by rapid thermal annealing. In addition to the annealing temperature, we report that the band gap shift can be also enhanced by increasing the CS level in the SQW. For instance, at an annealing temperature of 850 °C, the photoluminescence blue shift is found to reach more than 110 nm for the sample with 1.2%-CS SQW, but only 35 nm with 0.4%-CS SQW. We expect that this relatively larger atomic compositional gradient of In (and Ga) between the compressively strained quantum well and the barrier can facilitate the atomic interdiffusion and it thus leads to the larger band gap shift.
Partial order and a T0-topology in a set of finite quantum systems
Authors: Vourdas A.
Published: November 2012

A “whole-part” theory is developed for a set of finite quantum systems Σ(n) with variables in \documentclass[12pt]{minimal}\begin{document}${\mathbb {Z}}(n)$\end{document}Z(n). The partial order “subsystem” is defined, by embedding various attributes of the system Σ(m) (quantum states, density matrices, etc.) into their counterparts in the supersystem Σ(n) (for m|n). The compatibility of these embeddings is studied. The concept of ubiquity is introduced for quantities which fit with this structure. It is shown that various entropic quantities are ubiquitous. The sets of various quantities become T0-topological spaces with the divisor topology, which encapsulates fundamental physical properties. These sets can be converted into directed-complete partial orders, by adding “top elements.” The continuity of various maps among these sets is studied.
Dark solitons of the Qiao's hierarchy
Authors: Ivanov Rossen I. , Lyons Tony
Published: November 2012

We obtain a class of soliton solutions of the integrable hierarchy which has been put forward in a series of works by Qiao. The soliton solutions are in the class of real functions approaching constant value fast enough at infinity, the so-called “dark solitons.”
Dynamics of charge flow in the channel of a thin-film field-effect transistor
Authors: Bittle E. G. , Brill J. W. , Straley J. P.
Published: November 2012

The local conductivity in the channel of a thin-film field-effect transistor is proportional to the charge density induced by the local gate voltage. We show how this determines the frequency- and position-dependence of the charge induced in the channel for the case of “zero applied current”: zero drain-source voltage with charge induced by a square-wave voltage applied to the gate, assuming constant mobility and negligible contact impedances. An approximate expression for the frequency dependence of the induced charge in the center of the channel can be conveniently used to determine the charge mobility. Fits of electro-optic measurements of the induced charge in organic transistors are used as examples.
Van Hove singularities in graphene nanoflakes
Authors: Zhou Aiping , Sheng Weidong
Published: November 2012

The density of states of graphene diverge at six M points in the Brillouin zone, known as Van Hove singularities. For a finite graphene structure, such as nanoflake, similar singularities are found to emerge in the energy spectrum as highly degenerate states. We investigate these degenerate states in various graphene nanoflakes and show that the existence of the singularities is strongly dependent on the geometry, size, and even edge profile of the structures. While highly degenerate states are seen for all the hexagonal structures, no singularities can be found for any triangular nanoflake which has even number of carbon rings along each side. We further reveal that the nanoflakes with the Van Hove singularities exhibit very different optical absorption spectrum from those structures where the singularities are absent. More interestingly, we find that these highly degenerate states can survive when the structural symmetry is broken by a vacancy. Depending on its location and the sizes of structures, the defect may even enhance the degeneracy of the states at the singularities.
Pulsed terahertz radiation due to coherent phonon-polariton excitation in 〈110〉 ZnTe crystal
Authors: Tu C. M. , Ku S. A. , Chu W. C. , Luo C. W. , Chen J. C. , Chi C. C.
Published: November 2012

Pulsed terahertz (THz) radiation, generated through optical rectification (OR) by exciting 〈110〉 ZnTe crystal with ultrafast optical pulses, typically consists of only a few-cycles of electromagnetic field oscillations with a duration about a couple of picoseconds. However, it is possible, under appropriate conditions, to generate a long damped oscillation tail (LDOT) following the main cycles. The LDOT can last tens of picoseconds and its Fourier transform shows a higher and narrower frequency peak than that of the main pulse. We have demonstrated that the generation of the LDOT depends on both the duration of the optical pulse and its central wavelength. Furthermore, we have also performed theoretical calculations based upon the OR effect coupled with the phonon-polariton mode of ZnTe and obtained theoretical THz waveforms in good agreement with our experimental observation.
Asymmetric chiral alignment in magnetized plasma turbulence
Authors: Kendl A.
Published: November 2012

Multi species turbulence in inhomogeneous magnetised plasmas is found to exhibit symmetry breaking in the dynamical alignment of a third species with the fluctuating electron density and vorticity with respect to the magnetic field direction and the species’ relative background gradients. The possibility of truly chiral aggregation of charged molecules in magnetized space plasma turbulence is discussed.