bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of spherical inclusions on scattering properties of small ice cloud particles
Authors: Hong Gang , Minnis Patrick 
Published: March 2015

AbstractThe single‐scattering properties of small ice crystals containing four types of spherical inclusions, ammonium sulfate (NH4)2SO4, ammonium nitrate NH3NO3, air bubbles, and soot, are investigated at 0.65 and 2.13 µm. Small, randomly oriented hexagonal ice columns with spherical inclusions that are randomly distributed with standard gamma size distributions in the columns are considered in the present study. Ice crystals with inclusions of (NH4)2SO4 and NH3NO3 essentially have the same features due to their similar refractive indices. Nonzero scattering matrix elements are sensitive to inclusion type and amount, and show differences between 0.65 and 2.13 µm. The extinction efficiency Qe of small ice crystals at 0.65 µm is near 2.0 and essentially unaffected by variations in inclusion volume, in contrast to strong influences of inclusion amount on Qe at 2.13 µm. The single‐scattering albedo ϖ0 of ice crystals, nearly equal to 1.0, is not affected by inclusions of (NH4)2SO4, NH3NO3, and air bubbles. Soot inclusions strongly affect ϖ0, which decreases to about 0.5 with increasing soot amounts. The asymmetry factor g is substantially affected by (NH4)2SO4, NH3NO3, and soot and the variations in their amounts. Full Stokes parameters of cirrus clouds consisting of uniform hexagonal ice columns with inclusions are computed using a polarized radiative transfer model. Sensitivities of light intensity and polarization of cirrus clouds to types and amounts of inclusions and cirrus cloud optical thicknesses are found to depend on wavelength. The present results suggest that different types of inclusions for small ice crystals should be considered when developing realistic ice crystal optical properties, and that light intensity and polarization of cirrus clouds and their angular distribution features, in the absence of other effects such as cavities and surface roughness, imply the potential for identifying pure ice crystals from those with aerosol inclusions.
Resolution‐dependent behavior of subgrid‐scale vertical transport in theZhang‐McFarlane convection parameterization
Authors: Xiao Heng , Gustafson William I. , Hagos Samson M. , Wu Chien‐Ming , Wan Hui 
Published: March 2015

AbstractTo better understand the behavior of quasi‐equilibrium‐based convection parameterizations at higher resolution, we use a diagnostic framework to examine the resolution‐dependence of subgrid‐scale vertical transport of moist static energy as parameterized by the Zhang‐McFarlane convection parameterization (ZM). Grid‐scale input to ZM is supplied by coarsening output from cloud‐resolving model (CRM) simulations onto subdomains ranging in size from 8 × 8 to 256 × 256 km2. Then the ZM‐based parameterization of vertical transport of moist static energy for scales smaller than the subdomain size () are compared to those directly calculated from the CRM simulations () for different subdomain sizes. The ensemble meandecreases by more than half as the subdomain size decreases from 128 to 8 km across whiledecreases with subdomain size only for strong convection cases and increases for weaker cases. The resolution dependence ofis determined by the positive‐definite grid‐scale tendency of convective available potential energy (CAPE) in the convective quasi‐equilibrium (QE) closure. Further analysis shows the actual grid‐scale tendency of CAPE (before taking the positive definite value) andbehave very similarly as the subdomain size changes because they are both tied to grid‐scale advective tendencies. We can improve the resolution dependence ofsignificantly by averaging the grid‐scale tendency of CAPE over an appropriately large area surrounding each subdomain before taking its positive definite value. Even though the ensemble meandecreases with increasing resolution, its variability increases dramatically.cannot capture such increase in the variability, suggesting the need for stochastic treatment of convection at relatively high spatial resolution (8 or 16 km).
Impact of viscous fingering and permeability heterogeneity on fluid mixing in porous media
Authors: Nicolaides Christos , Jha Birendra , Cueto‐Felgueroso Luis , Juanes Ruben 
Published: March 2015

AbstractFluid mixing plays a fundamental role in many natural and engineered processes, including groundwater flows in porous media, enhanced oil recovery, and microfluidic lab‐on‐a‐chip systems. Recent developments have explored the effect of viscosity contrast on mixing, suggesting that the unstable displacement of fluids with different viscosities, or viscous fingering, provides a powerful mechanism to increase fluid‐fluid interfacial area and enhance mixing. However, existing studies have not incorporated the effect of medium heterogeneity on the mixing rate. Here, we characterize the evolution of mixing between two fluids of different viscosity in heterogeneous porous media. We focus on a practical scenario of divergent‐convergent flow in a quarter five spot geometry prototypical of well‐driven groundwater flows. We study by means of numerical simulations the impact of permeability heterogeneity and viscosity contrast on the breakthrough curves and mixing efficiency, and we rationalize the nontrivial mixing behavior that emerges from the competition between the creation of fluid‐fluid interfacial area and channeling.
A hydrometeorological approach for probabilistic simulation of monthly soil moisture under bare and crop land conditions
Authors: Das Sarit Kumar , Maity Rajib 
Published: March 2015

AbstractThis study focuses on the probabilistic estimation of monthly soil moisture variation by considering (a) the influence of hydrometeorological forcing to model the temporal variation and (b) the information of Hydrological Soil Groups (HSGs) and Agro‐Climatic Zones (ACZs) to capture the spatial variation. The innovative contributions of this study are: (i) development of a Combined Hydro‐Meteorological (CHM) index to extract the information of different influencing hydrometeorological variables, (ii) consideration of soil‐hydrologic characteristics (through HSGs) and climate regime‐based zoning for agriculture (through ACZs), and (iii) quantification of uncertainty range of the estimated soil moisture. Usage of Supervised Principal Component Analysis (SPCA) in the development of the CHM index helps to eliminate the “curse of dimensionality,” typically arises in the multivariate analysis. The usage of SPCA also ensures the maximum possible association between the developed CHM index and soil moisture variation. The association between these variables is modeled through their joint distribution which is obtained by using the theory of copula. The proposed approach is also spatially transferable, since the information on HSGs and ACZs is considered. The “leave‐one‐out” cross‐validation (LOO‐CV) approach is adopted for stations belong to a particular HSG to examine the spatial transferability. The simulated soil moisture values are also compared with a few existing soil moisture data sets, derived from different Land Surface Models (LSMs) or retrieved from different satellite‐based missions. The potential of the proposed approach is found to be promising and even applicable to crop land also, though with a lesser degree of efficiency as compared to bare land conditions.
Ionospheric storms—A challenge for empirical forecast of the total electron content
Authors: Borries C. , Berdermann J. , Jakowski N. , Wilken V. 
Published: March 2015

AbstractSince the last decades, the functioning of society depends more and more on well‐functioning communication and navigation systems. As the availability and reliability of most of these satellite‐based systems can be severely impacted by ionospheric storms, the accurate forecast of these events becomes a required task for mitigating social and economic risks. Here we aim to make initial steps toward an empirical model for ionospheric perturbations related to space weather events that are observable in the total electron content (TEC). The perturbation TEC forecast model will be a fast and robust approach, improving TEC forecasts based on climatological models during storm conditions. The derivation of such a model is a challenging task, because although a general dependence of the storm features (enhancement or depletion of electron density) on the storm onset time, local time, season and geomagnetic latitude is well known, there is a large deviation from the mean behavior. For a better understanding of storm conditions, this paper presents analyses of ionospheric storms observed in the TEC, broken down into diverse classes of storms. It provides a detailed characterization of the typical ionospheric storm behavior over Europe from high to midlatitudes, beyond case studies. Generally, the typical clear strong TEC enhancement starting in high latitudes and propagating equatorward is found to be strongest for storms starting in the morning hours independent of the season. In midlatitudes, it is strongest during noon. In addition, a clear difference between summer and winter storms is reported. While only winter storms develop high‐latitude TEC enhancements, only summer storms typically exhibit TEC depletions during the storm recovery phase. During winter storms TEC enhancements can also occur the day following the storm onset, in contrast to summer storms. Strong correlation of TEC perturbation amplitudes to the Bz component of the interplanetary magnetic field and to a proxy of the polar cap potential are shown especially for summer midlatitude TEC enhancements during storms with and onset in the morning hours (6 to 12 UT over Europe) and for winter high‐latitude TEC enhancements (around 60∘N). The results indicate the potential to derive improved predictions of maximum TEC deviations during space weather events, based on solar wind measurements.
Upwelling induced by the frictional stress curl and vertical squeezing of the vortex tube over a submerged valley in the East China Sea
Authors: Liu Zhiqiang , Gan Jianping 
Published: March 2015

AbstractWe conducted a process‐oriented modeling study to investigate the characteristics and dynamics of the prominent upwelling over a vast submerged valley in the East China Sea (ECS). The valley is inversely funnel‐shaped with the west bank and the east bank oriented in the north‐south direction. A cross‐bank upward transport occurred along the west bank. It intensified northward and peaked around the head of the valley. An along‐bank southward pressure gradient force (
) formed the cross‐bank geostrophic transport for the upwelling over the valley. The PGF reached its maxima at the head of the valley. Our momentum and vorticity dynamic analyses revealed that a bottom stress curl mainly contributed the PGF along the west bank. At the same time, both the bottom stress curl and the nonlinear vorticity advection contributed to the PGF around the head. The bottom stress curl was due to the bottom shear vorticity of the coastal current and the curvature vorticity around the head. The nonlinear vorticity advection formed because of the vertical squeezing of vortex tube as the current flowed over the valley. The nonlinearity mainly affected the PGF around the head, whereas the bottom stress curl contributed to the PGF over the entire valley. The ratio of the nonlinear to frictional contributions to the PGF increased as the coastal current intensified. Our study demonstrates that the PGF that drives the upwelling over the valley is the combined result of the nonlinearity due to vertical squeezing of vortex tube and bottom frictional effects.
Spreadsheet Modeling for Operations Research Practice
Authors: Grossman Thomas 
Published: March 2015

Abstract
This article presents the essential information for operations research practitioners to use spreadsheets to enhance their practice. We provide examples of high impact operations research models implemented in a spreadsheet. We discuss the characteristics of the spreadsheet as a programming language, provide an overview of spreadsheet engineering principles, and a summary of the research on spreadsheet errors, emphasizing that practitioners with the sophistication to code in traditional languages can code complex models in a spreadsheet, provided they approach the task with equivalent diligence. We present four approaches to using spreadsheets in operations research practice. There is a rich set of add‐ins that implement operations research techniques in a spreadsheet, such as Monte Carlo simulation, optimization (including very large and challenging models), statistics and other data‐driven techniques, business function‐specific analysis, as well as productivity tools for spreadsheet developers.
Analytic Modeling of Insurgencies
Authors: Kress Moshe 
Published: March 2015

AbstractLegacy force‐on‐force models are symmetrical; they reflect the fact that the dynamics of both sides in the conflict is governed by similar rules. These models have also traditionally focused on the physical aspects of armed conflicts—fire, attrition, detection, movement, logistics, and so on. Insurgency models are different in two key aspects: (i) they are asymmetrical and (ii) they contain, in addition to the physical aspects, significant cognitive, social, cultural, political, and economic factors. The reason for the asymmetry is the way insurgents evolve and operate, and the emergence of nonphysical factors is due to the major role of civilians in such conflicts. This article focuses on analytic modeling of insurgencies and counterinsurgency operations, describing both the physical and nonphysical components of such armed conflicts.
Association of Physical Activity Measured by Accelerometer, Knee Joint Abnormalities, and Cartilage T2 Measurements Obtained From 3T Magnetic Resonance Imaging: Data From the Osteoarthritis Initiative
Authors: Kretzschmar M. , Lin W. , Nardo L. , Joseph G. B. , Dunlop D. D. , Heilmeier U. , Nevitt M. C. , Alizai H. , McCulloch C. E. , Lynch J. A. , Link T. M. 
Published: March 2015

ObjectiveTo study the cross‐sectional association between physical activity measured with an accelerometer, structural knee abnormalities, and cartilage T2 values assessed with 3T magnetic resonance imaging (MRI).MethodsWe included 274 subjects from the Osteoarthritis Initiative cohort without definite radiographic osteoarthritis (Kellgren/Lawrence grades 0 and 1) and with at most mild pain, stiffness, and functional limitation in the study knee (Western Ontario and McMaster Universities Osteoarthritis Index scale 0–1), which had not limited their activity due to knee pain. Physical activity was measured over 7 days with an ActiGraph GT1M accelerometer. Subjects were categorized by quartile of physical activity based on the average daily minutes of moderate to vigorous physical activity (mv‐PA). MRI images of the right knee (at 48‐month visit) were assessed for structural abnormalities using a modified Whole‐Organ Magnetic Resonance Imaging Score (WORMS) and for T2 relaxation times derived from segmented cartilage of 4 femorotibial regions and the patella. WORMS grades and T2 measurements were compared between activity quartiles using a linear regression model. Covariates included age, sex, body mass index, knee injury, family history of knee replacement, knee symptoms, hip and ankle pain, and daily wear time of the accelerometer.ResultsHigher mv‐PA was associated with increased severity (P = 0.0087) and number of lesions of the medial meniscus (P = 0.0089) and with severity of bone marrow edema lesions (P = 0.0053). No association between cartilage lesions and mv‐PA was found. T2 values of cartilage (loss, damage, and abnormalities) tended to be greater in the higher quartiles of mv‐PA, but the differences were nonsignificant.ConclusionIn knees without radiographic osteoarthritis in subjects with no or mild knee pain, higher physical activity levels were associated with increases in meniscal and bone marrow edema pattern lesions.
Association of Objectively Measured Physical Activity and Metabolic Syndrome Among US Adults With Osteoarthritis
Authors: Liu Shao‐Hsien , Waring Molly E. , Eaton Charles B. , Lapane Kate L. 
Published: March 2015

ObjectiveTo investigate the association between objectively measured physical activity and metabolic syndrome among adults with osteoarthritis (OA).MethodsUsing cross‐sectional data from the 2003–2006 National Health and Nutrition Examination Survey, we identified 566 adults with OA with available accelerometer data assessed using Actigraph AM‐7164 and measurements necessary to determine metabolic syndrome by the Adult Treatment Panel III. Analysis of variance was conducted to examine the association between continuous variables in each activity level and metabolic syndrome components. Logistic models estimated the relationship of quartile of daily minutes of different physical activity levels to odds of metabolic syndrome adjusted for socioeconomic and health factors.ResultsAmong persons with OA, most were women average age of 62.1 years and average disease duration of 12.9 years. Half of adults with OA had metabolic syndrome (51.0%; 95% confidence interval [95% CI] 44.2%–57.8%), and only 9.6% engaged in the recommended 150 minutes per week of moderate/vigorous physical activity. Total sedentary time was associated with higher rates of metabolic syndrome and its components, while light and objectively measured moderate/vigorous physical activity was inversely associated with metabolic syndrome and its components. Higher levels of light activity were associated with lower prevalence of metabolic syndrome (quartile 4 versus quartile 1: adjusted odds ratio 0.45, 95% CI 0.24–0.84, P for linear trend < 0.005).ConclusionMost US adults with OA are sedentary. Increased daily minutes in physical activity, especially in light intensity, is more likely to be associated with decreasing prevalence of metabolic syndrome among persons with OA.
Effect of N2 pretreatment on the basicity, structural change, and isomerization activity of MgO and MgO/Mg(OH)2 catalysts
Authors: Suttibut Prinyanee , Suriye Kongkiat , Kunjara Na Ayudhya Sirachaya , Praserthdam Piyasan , Panpranot Joongjai 
Published: March 2015

AbstractAs revealed by the X‐ray diffraction, basicity titration, and Fourier transform infrared spectroscopy results, changes in the structural properties, basicity, and isomerization activities were observed on the MgO catalysts upon N2 pretreatment at 325 °C followed by isomerization reaction at 125 °C. These changes became less pronounced when the starting catalysts contained Mg(OH)2 phase or when the catalysts were pretreated under N2 at high temperature alone (without reaction). Because of the limited amount of O2 during 1‐butene isomerization, the single‐phase MgO could transform into the mixed MgO/Mg(OH)2 catalysts, and the basicity and the isomerization activity were enhanced. Higher temperature pretreatment (i.e. 527 °C), however, led to the changes of Mg(OH)2 back to the single MgO phase and/or sintering of MgO. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
Adjustable amine–epoxy composition in a stratified thin film with a spin‐coating process: A useful tool for establishing relationships between the local glass‐transition temperature at the interface and the network structure
Authors: Carriere Pascal , Onard Sandra , Martin Isabelle , Chailan Jean‐François 
Published: March 2015

ABSTRACTAn easy method for preparing supported homogeneous epoxy–amine thin films on a silica surface consisting of two distinct layers was developed via spin coating from epoxy–amine solutions. Because of these two layers had the controlled properties of the upper layer, we showed that it was possible to precisely control the epoxy–amine stoichiometry in the sublayer through the initial epoxy–amine ratio, the spin‐cast process, and the overall film thickness. First, in the thin films, the primary amine–epoxy conversion was constant, whatever the thickness and initial epoxy–amine stoichiometry for a given curing schedule. As the primary amine conversion can be independently tuned in thin films, it thus provided a rather unique and easy method for better understanding the relationship between the network structure curing at the interface and the resulting properties, such as the glass‐transition temperature (Tg) and elastic modulus. Here, we also showed that we could access the local Tg; this implied a potential application of these experimental data in predictive composite material properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42078.
Morphology, rheology, and mechanical properties of a new nanobiocomposite
Authors: La Mantia Francesco P. , Mistretta Maria Chiara , Palermo Salvatore , Ceraulo Manuela 
Published: March 2015

ABSTRACTNanobiocomposites are a new class of biodegradable polymer materials with an ultrafine phase dispersion of the order of a few nanometers in a biodegradable polymer matrix that shows very interesting properties often very different from those of conventional filled polymers. In this work the morphology and the rheological and mechanical properties of a new nanobiocomposite made of a biodegradable copolyester based blend with an organomodified montmorillonite have been investigated to evaluate its possible use in several applications. SAXS diffractograms and TEM micrographs show that the in both the adopted processing conditions an hybrid intercalated/exfoliated morphology is observed. Rheological behavior is significantly influenced by the presence of the filler and more important, depends on the type of the applied type of flow. As for the mechanical properties, the elastic modulus strongly increases, while the elongation at break remarkably decreases. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42128.
Effect of the ionic liquid [bmim]PF6 on the nonisothermal crystallization kinetics behavior of poly(ether‐b‐amide)
Authors: Bai Yunxiang , Wu Guoliang , Zhang Qian , Zhang Chunfang , Gu Jin , Sun Yuping 
Published: March 2015

ABSTRACTBlending ionic liquid with crystalline polymer permits the design of new high‐performance composite materials. The final properties of these materials are critically depended on the degree of crystallinity and the nature of crystalline morphology. In this work, nonisothermal crystallization behavior of poly(ether‐b‐amide) (Pebax®1657)/room temperature ionic liquid (1‐butyl‐3‐methylimidazolium hexafluorophosphate, [bmim]PF6) was investigated by differential scanning calorimetry. The presence of [bmim]PF6 can retard the nucleation of Pebax®1657 and lead to the crystallization depression of the PA block and the crystalline disappearance of the PEO block. However, the dilution effect of the IL results in a higher growth rate of crystallization of PA block. The influence of [bmim]PF6 content and cooling rate on crystallization mechanism and spherulitc structures was determined by the Avrami equation modified by Jeziorny and Mo's methods, whereas the Ozawa's approach fails to describe the nonisothermal crystallization behavior of Pebax®1657/[bmim]PF6 blends. In the modified Avrami analysis, the Avrami exponent of PA blocks, n > 3, for pure Pebax®1657, while 3 > n > 2 for Pebax®1657/[bmim]PF6 blends testifies the transformation of crystallization growth pattern induced by [bmim]PF6 from three‐dimensional growth of spherulites to a combination of two‐ and three‐dimensional spherulitic growth. Further, lower activation energy for the nonisothermal crystallization of PA blocks of Pebax®1657 can be observed with the increase of [bmim]PF6 content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42137.