High Excess Research Articles

An Evaluation of Compensation Benchmarking Peer Groups Based on Mutual Peer-Designating Behaviors

In this paper, I argue that firms mutually recognizing each other as compensation benchmarking peers constitute viable competitors in the same CEO labor market, and that non-mutual peer relationships can serve as a tool to evaluate firms’ executive compensation practices. In particular, I ask why some of the firm’s chosen peers do not consider to select the base firm back despite listing other firms as compensation benchmarking peers. I hypothesize that such one-sided peer choices are driven either by rent extraction or motivational motives. My analyses show that firms with a larger proportion of such one-sided peer choices are associated with higher compensation via setting a higher benchmark level. Consistent with rent extraction motives, such firms are also associated with higher excess compensation and lower firm performance. In additional analyses, I show that the proportion of one-sided peers increases when firms adjust their benchmark level upward by adding higher compensated peers and/or dropping lower compensated peers. Collectively, the findings suggest that patterns in mutual compensation benchmarking peer-designating behaviors can serve as a tool to evaluate firms’ executive compensation practices.

BREAKING THE CURVE WITH CANDELS: A BAYESIAN APPROACH TO REVEAL THE NON-UNIVERSALITY OF THE DUST-ATTENUATION LAW AT HIGH REDSHIFT

ABSTRACT Dust attenuation affects nearly all observational aspects of galaxy evolution, yet very little is known about the form of the dust-attenuation law in the distant universe. Here, we model the spectral energy distributions of galaxies at z ∼ 1.5–3 from CANDELS with rest-frame UV to near-IR imaging under different assumptions about the dust law, and compare the amount of inferred attenuated light with the observed infrared (IR) luminosities. Some individual galaxies show strong Bayesian evidence in preference of one dust law over another, and this preference agrees with their observed location on the plane of infrared excess (IRX, / ) and UV slope (β). We generalize the shape of the dust law with an empirical model, where k λ is the dust law of Calzetti et al., and show that there exists a correlation between the color excess and tilt δ with . Galaxies with high color excess have a shallower, starburst-like law, and those with low color excess have a steeper, SMC-like law. Surprisingly, the galaxies in our sample show no correlation between the shape of the dust law and stellar mass, star formation rate, or β. The change in the dust law with color excess is consistent with a model where attenuation is caused by scattering, a mixed star–dust geometry, and/or trends with stellar population age, metallicity, and dust grain size. This rest-frame UV-to-near-IR method shows potential to constrain the dust law at even higher redshifts ( ).

Centrifuge testing to evaluate the liquefaction response of air-injected partially saturated soils beneath shallow foundations

Earthquake-induced liquefaction of saturated soils continues to cause severe damage to structures with shallow foundations. In recent years, artificially reducing the degree of saturation and forming partially saturated zones within saturated soils has been proposed as a liquefaction mitigation technique. This study experimentally investigates the liquefaction response of air-injected partially saturated soils beneath shallow foundations. A series of centrifuge tests were conducted on the shallow foundations with different bearing pressures. The results of the tests show that the generation of excess pore pressures and consequent liquefaction-induced settlements of shallow foundations were a strong function of the degree of saturation. Forming spatially distributed partially saturated zones in the liquefiable soils limited the development of high excess pore pressures and liquefaction susceptibility of soils, particularly at the higher confining stresses. The reduction in the degree of saturation of soils decreased the depth of liquefied soil layer, and increased the resistance of soil to the bearing capacity failure. On the other hand, the decrease in the degree of saturation of liquefiable soils led the larger accelerations to be transmitted to the foundations through unliquefied soil zones. It is therefore concluded that use of air-injection as a liquefaction mitigation measure does reduce structural settlements, but will have the consequence of larger structural accelerations.

Oxidation of flavonoids by hypochlorous acid: reaction kinetics and antioxidant activity studies

Flavonoids, plant polyphenols, ubiquitous components of human diet, are excellent antioxidants. Hypochlorous acid (HOCl), produced by activated neutrophils, is highly reactive chlorinating and oxidizing species. It has been reported earlier that flavonoids are chlorinated by HOCl. Here we show that flavonoids from flavonol subclass are also oxidized by HOCl, but only if the latter is in a large molar excess (≥ 10). The kinetics of this reaction was studied by stopped-flow spectrophotometry, at different pH. We found that flavonols were oxidized by HOCl with the rate constants of the order of 104–105 M−1 s−1 at pH 7.5. Antioxidant activity of HOCl-modified flavonoids was measured by 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) method. Slightly higher antioxidant activity, compared to parent compounds, was observed for flavonols after their reaction with equimolar or moderate excess of HOCl whereas flavonols treated with high molar excess of HOCl exhibited decrease in antioxidant activity. The mechanism of flavonoid reaction with HOCl at physiological pH is proposed, and biological consequences of this reaction are discussed.

Dislocation Nucleation on Grain Boundaries: Low Angle Twist and Asymmetric Tilt Boundaries

We investigate the mechanisms of incipient plasticity at low angle twist and asymmetric tilt boundaries in fcc metals. To observe plasticity of grain boundaries independently of the bulk plasticity, we simulate nanoindentation of bicrystals. On the low angle twist boundaries, the intrinsic grain boundary (GB) dislocation network deforms under load until a dislocation segment compatible with glide on a lattice slip plane is created. The half loops are then emitted into the bulk of the crystal. Asymmetric twist boundaries considered here did not produce bulk dislocations under load. Instead, the boundary with a low excess volume nucleated a mobile GB dislocation and additional GB defects. The GB sliding proceeded by motion of the mobile GB dislocation. The boundary with a high excess volume sheared elastically, while bulk-nucleated dislocations produced plastic relaxation.

Tailoring antiferroelectricity with high energy-storage properties in Bi0.5Na0.5TiO3–BaTiO3 ceramics by modulating Bi/Na ratio

Antiferroelectric materials form a potential candidate for ceramic-based high energy storage applications owing to their low loss and high energy density. Here, we demonstrate that the antiferroelectric phase with high energy-storage properties in 0.94Bi0.5+xNa0.5−xTiO3–0.06BaTiO3 (BNTx–BT) ceramics at room-temperature is modulated by tailoring compositions. Our results show that the metastable antiferroelectric phase at room-temperature modulated by the Bi/Na ratio with a high excess in Bi3+ and/or a deficiency in Na+, can be induced to the FE phase by applying electrical field, leading to double hysteresis. The high energy storage density W = 1.76 J/cm3 for x = 0.05 BNTx–BT ceramics by modulating Bi/Na ratio is obtained, suggesting a promising candidate lead-free energy-storage material.

Isotopic composition in precipitation and groundwater in the northern mountainous region of the Central Valley of Costa Rica

ABSTRACTThe linkage between precipitation and recharge is still poorly understood in the Central America region. This study focuses on stable isotopic composition in precipitation and groundwater in the northern mountainous region of the Central Valley of Costa Rica. During the dry season, rainfall samples corresponded to enriched events with high deuterium excess. By mid-May, the Intertropical Convergence Zone poses over Costa Rica resulting in a depletion of 18O/16O and 2H/H ratios. A parsimonious four-variable regression model (r2 = 0.52) was able to predict daily δ18O in precipitation. Air mass back trajectories indicated a combination of Caribbean Sea and Pacific Ocean sources, which is clearly depicted in groundwater isoscape. Aquifers relying on Pacific-originated recharge exhibited a more depleted pattern, whereas recharge areas relying on Caribbean parental moisture showed an enrichment trend. These results can be used to enhance modelling efforts in Central America where scarcity of long-term data limits water resources management plans.

Nickel retention by an ion-imprinted polymer: Wide-range selectivity study and modelling of the binding structures

In this work, a new nickel-selective imprinted polymer was synthesized, using a 1:3 complex of nickel: ([Ni(Vbamp)3](ClO4)2), Vbamp being N-(4-vinylbenzyl)-2-(aminomethyl)pyridine. The ion-imprinted polymer and its corresponding non-imprinted polymer were tested for their nickel retention capacity over a wide range of concentration at pH 4.0 and 7.0. Their selectivity was also checked with various Ni/Co and Ni/Zn ratios at pH 4.0 and 7.0. It was shown that even in strongly disfavoring conditions (high excess of competitor), the IIP’s selectivity remained performing. This original broad retention study allowed the determination of the variations of the selectivity factors according to the increasing presence of competitors, a clearly innovative approach. The efficiency of the polymers in natural samples from Saimaa Lake (Lappeenranta, Finland) and Mediterranean Sea (Toulon, France) was also assessed. Finally, the whole dataset was simultaneously modelled using a software usually dedicated to the determination of natural ligand’s binding properties. The modelling using different kinds of binding sites (1:1, 1:2 and 1:3) allowed the precise determination of the synthesized polymers’ structure and binding ability.

Jet fragmentation in p + Pb and Pb + Pb with ATLAS

The modification of jets in heavy ion collisions is a central tool to study the properties of QCD matter at high temperature and its interaction with hard probes. Jet production in heavy ion collisions is observed to be suppressed relative to expectations from pp collisions and the measurement of the longitudinal fragmentation functions in Pb+Pb can provide insight into mechanism of the modification of the parton showering by the QCD medium. In proton-nucleus collisions, a large amount of hot QCD matter is not expected to be made and no evidence of jet suppression is observed. However, an excess is observed in the production of high momentum charged particles in p+Pb collisions relative to pp collisions. The p+Pb fragmentation functions can provide insight into the high momentum charged particle excess and into a possible influence of Pb+Pb jet fragmentation by effects due to the nuclear initial state. The ATLAS measurements of charged particle fragmentation functions in pp, p+Pb, and Pb+Pb collisions are presented.

Effect of supplemental dietary leucine and immune system stimulation on whole-body nitrogen utilization in starter pigs.

The increase in circulating pro-inflammatory cytokines following an immune challenge (e.g., with bacterial lipopolysaccharide [LPS]) causes a disruption in normal AA metabolism and increases visceral protein synthesis at the expense of muscle protein synthesis. The objective of this study was to determine the effect of supplemental dietary Leu on the dynamics of whole body nitrogen (N) retention in starter pigs before and after immune system stimulation (ISS) induced by LPS. A total of 28 starter pigs (14.46 ± 0.73 kg BW) were assigned to isoenergetic and isonitrogenous diets formulated to supply essential AA 10% above estimated requirements for maximum whole-body protein deposition (PD) and to contain increasing amounts of Leu: CON (1.36% SID Leu); LEU-M (2.04% SID Leu); and LEU-H (2.72% SID Leu). Pigs were housed in metabolic crates, scale-fed every 4 h based on BW, and adjusted to dietary treatments for 5 d. The 108-h N-balance experiment was divided into two periods: prechallenge (before LPS challenge; six 12-h collections) and challenge (after LPS challenge; three 12-h collections) periods. In both periods, blood was collected to determine plasma AA and urea N concentrations. At the start of the challenge period, one-half of the pigs fed CON and all pigs fed LEU-M and LEU-H were challenged with LPS (ISS+; 30 µg/kg injected intramuscularly); the remaining pigs fed CON were injected with saline (ISS-). Whole-body N retention was determined during subsequent 12-h collections. Plasma free Leu concentration increased linearly with increasing Leu content in the diet before LPS was administered (CON, 124 µmol/L; LEU-M, 185 µmol/L; LEU-H, 227 µmol/L; < 0.01). During the prechallenge period, N retention was lower in pigs fed LEU-M ( < 0.01) and there was no difference between pigs fed CON and LEU-H (7.91, 7.18, and 7.71 g/12 h for CON, LEU-M, and LEU-H, respectively). During the challenge period, N retention in pigs fed CON was higher in ISS- than ISS+ (5.37 vs. 3.83 g/12 h; < 0.01) but was not affected by diet in ISS+ pigs (3.83, 3.21, and 3.45 g/12 h for CON, LEU-M, and LEU-H, respectively; > 0.10). In healthy pigs, feeding a high excess of dietary Leu induced an anabolic response to compensate for reduced N retention that occurred in pigs fed an intermediate excess of dietary Leu. There was no effect of supplemental Leu on N retention in pigs after an LPS challenge.

Geophysical, isotopic, and hydrogeochemical tools to identify potential impacts on coastal groundwater resources from Urmia hypersaline Lake, NW Iran.

Measurements of major ions, trace elements, water-stable isotopes, and geophysical soundings were made to examine the interaction between Urmia Aquifer (UA) and Urmia Lake (UL), northwest Iran. The poor correlation between sampling depth and Cl(-) concentrations indicated that the position of freshwater-saltwater interface is not uniformly distributed in the study area, and this was attributed to aquifer heterogeneities. The targeted coastal wells showed B/Cl and Br/Cl molar ratios in the range of 0.0022-2.43 and 0.00032-0.28, respectively. The base-exchange index (BEI) and saturation index (SI) calculations showed that the salinization process followed by cation-exchange reactions mainly controls changes in the chemical composition of groundwater. All groundwater samples are depleted with respect to δ(18)O (-11.71 to -9.4 ‰) and δD (-66.26 to -48.41 ‰). The δ(18)O and δD isotope ratios for surface and groundwater had a similar range and showed high deuterium excess (d-excess) (21.11 to 31.16 ‰). The high d-excess in water samples is because of incoming vapors from the UL mixed with an evaporated moisture flux from the Urmia mainland and incoming vapors from the west (i.e., Mediterranean Sea). Some saline samples with low B/Cl and Br/Cl ratios had depleted δ(18)O and δD. In this case, due to freshwater flushing, the drilled wells in the coastal playas and salty sediments could have more depleted isotopes, more Cl(-), and consequently smaller B/Cl and Br/Cl ratios. Moreover, the results of hydrochemical facies evolution (HFE) diagram showed that because of the existence fine-grained sediments saturated with high density saltwater in the coastal areas that act as a natural barrier, increasing the groundwater exploitation leads to movement of freshwaters from recharge zones in the western mountains not saltwater from UL. The highly permeable sediments at the junction of the rivers to the lake are characterized by low hydraulic gradient and high hydraulic conductivity. These properties enhance the salinization of groundwater observed in the study area. The main factors influencing the salinity are base-exchange reactions, invasion of highly diluted saltwater, dissolution of salty pans, and water chemistry evolution along flow paths.

Modeling jointly low, moderate, and heavy rainfall intensities without a threshold selection

AbstractIn statistics, extreme events are often defined as excesses above a given large threshold. This definition allows hydrologists and flood planners to apply Extreme‐Value Theory (EVT) to their time series of interest. Even in the stationary univariate context, this approach has at least two main drawbacks. First, working with excesses implies that a lot of observations (those below the chosen threshold) are completely disregarded. The range of precipitation is artificially shopped down into two pieces, namely large intensities and the rest, which necessarily imposes different statistical models for each piece. Second, this strategy raises a nontrivial and very practical difficultly: how to choose the optimal threshold which correctly discriminates between low and heavy rainfall intensities. To address these issues, we propose a statistical model in which EVT results apply not only to heavy, but also to low precipitation amounts (zeros excluded). Our model is in compliance with EVT on both ends of the spectrum and allows a smooth transition between the two tails, while keeping a low number of parameters. In terms of inference, we have implemented and tested two classical methods of estimation: likelihood maximization and probability weighed moments. Last but not least, there is no need to choose a threshold to define low and high excesses. The performance and flexibility of this approach are illustrated on simulated and hourly precipitation recorded in Lyon, France.

(Invited) Elucidation of Lithiation Process As a Function of Structural and Chemical Transformations in Li2MnO3

The layered Li2MnO3 is a key component in the Li/Mn-rich cathode materials, and provides a representative end-member for the spectrum of compositions reported in the literature. While exhibiting excellent initial capacity, the Li excess materials suffer from voltage fade, high impedance, and poor rate capability, particularly in the Mn-rich, high Li excess concentration regime. In this talk we present insights about the Li electrochemical reactivity of Li2MnO3, from first-principles calculations. In particular, we elucidate the bulk lithiation/delithiation mechanism in pristine bulk LixMnO3 for 1< x < 2, involving coherent Li migration from the two Li-containing layers. Surprisingly, and contrary to expectations from available experimental results, we find that the pristine material exhibits excellent Li mobility enabling a Li rate capability on par with the well-known layered LiCoO2. For lower Li contents (x < 1), we have previously shown that Li2MnO3 becomes increasingly unstable towards manganese migration into the Li layer as well as oxygen loss at the surface. We systematically investigate the influence of these factors on the lithiation/delithiation process, which provides a hypothesis for the experimentally observed slow, and increasingly poor, electrochemical response of this material.

Influence of different electrolytes on bubble motion in ionic surfactants solutions

We determined the influence of concentration and type of added inorganic electrolytes on local and terminal velocities of bubbles in solutions of anionic, sodium n-hexadecylsulfate (SHS) and cationic, n-cetyltrimethylammonium bromide (CTAB) surfactants at concentrations below 3×10−6M. We found that addition of inorganic electrolyte strongly affected the bubble motion. Bubble local velocity passed through the maximum and reached terminal value, which for the electrolyte concentration around 10−3M, corresponded to the immobilized surface. Up to that concentration the width of the maximum of the local velocity profile decreased with electrolyte contents. Surprisingly, addition of higher concentration of inorganic electrolyte caused the reverse effect, the increase and broadening of the maximum, which depended on a type of counterions. For CTAB the effect followed the Hofmeister series of ion activity. That reverse effect may be connected with the modified structure of the dynamic adsorption layer in the presence of high excess of various anions or with the micelization enhanced surfactant desorption rate at the rear part of the rising bubble, reducing the Marangoni stress that immobilizes bubble surface.

The nutritive value of selected commercial dry dog foods

Received: 2015-11-03 | Accepted: 2015-11-06 | Available online: 2016-03-24 dx.doi.org/10.15414/afz.2016.19.01.25-28 The goal of this study was to analysed and compared the nutrients content of dry dog foods with nutrient content, which is declared by the manufacturer of the dry dog foods. 15 dry dog foods bought in the Slovak republic were analysed for dry matter, crude protein, crude fat, crude fiber, nitrogen free extract and ash concentration. Nutrients analysis of dry dog foods were realised in Laboratory of Quality and Nutritional Value of Feeds. We found, that only 6 from 15 dry dog food samples were in interval ± 5% from declared crude protein concentration; no sample was in interval ± 5% from declared crude fat concentration; only 2 from 15 dry dog food samples were in interval ± 5% from declared crude fiber concentration; only 4 from 15 dry dog food samples were in interval ± 5% from declared ash concentration. Analysed dry dog food samples have very different nutritive value in comparison to declared nutritive value on bale. The highest shortage was detected by the fat concentration. The highest excess was detected by the fiber concentration. Keywords : dogs, dry food, nutrients concentration, evaluation References ALVAREZ, E. and SANCHEZ, P. (2006) Dietary fiber. Nutricion Hospitalaria , vol. 21, Suppl., pp. 60-71. BAUER, J.E. 2006. Facilitative and functional fats in diets of cats and dogs. In Journal of the American Veterinary Medical Association , vol. 229, pp. 680-684. CASE, L. et al. (2011). Canine and Feline Nutrition: a resource for companion animal professionals . 3. ed. Missouri: Elsevier. HANUSOVSKÝ, O. (2014). Changes in minerals in colostrum of sows. In XX. scientific conference of students of Faculty of agrobiology and food resources. Nitra 23.4.2014 . Nitra: Slovak University of Agriculture in Nitra, pp. 29 (in Slovak). HARLOW, J. (1997) US pet food trends. Proceedings of the pet food forum . Chicago: Watts Publishing, pp. 355-364. HERKEĽ, R., VARGA, B. and MAJLAT, M. (2014). The analysis of fatty acids content in different plant oils. In IX. Scientific conference of PhD.-students with international participation. Nitra 14.11.2014 . Nitra: Slovak University of Agriculture in Nitra, pp. 34-37. KALLFELZ, F.A. (1989) Evaluation and use of pet foods: general consideration in using pet foods for adult maintenance. Veterinary Clinics of North America: Small Animal Practice , vol. 19, pp. 387-403. KRONFELD, D.S. (1982) Protein quality and amino acid profiles of common dog foods. Journal of the American Animal Hospital Association , vol. 18, pp. 679-683. LASEK, O., MILEJSKA, P. and KOWALSKI, Z.M. (2013) The use of gas-test techniques to study the fermentation process in the intestines of dogs. In DORSZEWSKI, P. et al. (eds.) Proc. conf. XLII Scientific Conference CAN CAS PAS. Bydgoszcz 18-20.9.2013 . Bydgoszcz: University of Technology and Life Science, pp. 165-166. MUDŘIK, Z. et al. (2014). Specification of calculating the energy needs for dogs used for a dogtrekking and canicross. In Lazar days of nutrition and veterinary dietetics XI. Kosice 2-3.9.2014 . Kosice: University of Veterinary Medicine and Pharmacy in Kosice, pp. 179-182. (in Czech). PISOVA, A. 2015. Organic matter digestibility of corn silage for horses. In XXI. scientific conference of students of Faculty of Agrobiology and Food Resources. Nitra 22.4.2015 . Nitra: Slovak University of Agriculture in Nitra, pp. 48 (in Slovak). SAMUELSON, A.C. and CUTTER, G.R. (1991) Dog biscuits: an aid in canine tartar control. The Journal of Nutrition , vol. 121, pp. S162. TVAROŽKOVA, K. (2015) Evaluation of the nutritional content of the granules and comparison of the composition of selected rations for dogs. In XXI. scientific conference of students of Faculty of Agrobiology and Food Resources. Nitra 22.4.2015. Nitra: Slovak University of Agriculture in Nitra, pp. 49 (in Slovak). TVRDA, E. et al. (2013) Mineral nutrients and male fertility. Journal of Microbiology, Biotechnology and Food Science , vol. 3, no. 1, pp. 1-14. VARGA, B. (2014) Profile of fatty acids in olive and hemp oils. In XX. scientific conference of students of Faculty of agrobiology and food resources. Nitra 23.4.2014 . Nitra: Slovak University of Agriculture in Nitra, pp. 40 (in Slovak). Regulation of the Slovak Ministry of Agriculture no. 2145 / 2004 - 100 (2004) about sampling of feeds and about laboratory testing and evaluation of feeds, pp. 342 (in Slovak).

Revealing the Intrinsic Li Mobility in the Li2MnO3 Lithium-Excess Material

One of the most promising avenues for future high energy Li-ion batteries originate from the family of Li-rich layered cathodes. However, while exhibiting excellent initial capacity, these materials also suffer from voltage fade, high impedance, and poor rate capability, particularly in the Mn-rich, high Li excess concentration regime. Though it is clear that the Li2MnO3 component contributes to the high capacity as well as the chemical and structural degradation of the material, the inherent ionic conductivity of the material has not been clarified. In this work, we investigate the delithiation mechanism, involving coherent Li migration from two layers by first-principles density functional theory. Surprisingly, and contrary to expectations from available experimental results, we find that the pristine material exhibits excellent Li mobility enabling facile Li extraction from both the transition metal layer and Li-layer. Generally, the Li-extractions are highly accelerated by di- and trivacancy clusters,...

Relationship between operational risk management, size, and ownership of Indian banks

Purpose The purpose of this paper is to analyse the relationship between operational risk management (ORM), size, and ownership of Indian banks. This is important in the context of financial crisis experienced by developed countries due to lax regulation. Design/methodology/approach ORM practices of Indian banks are proxied by excess capital (over the required minimum capital for operational risk). Size of a bank is measured as deposits plus advances. Our sample includes 61 Indian banks during the period from 2010 to 2013. The authors empirically examine the impact of bank size on excess capital using panel data regression model. Findings The results suggest that size of Indian banks is inversely related to excess capital held by them for managing operational risk. The inverse relationship implies that smaller banks hold higher excess capital over the required minimum as per Basel norms. There is no significant relationship between ownership (public, private and foreign) and excess capital held by banks for managing operational risk. Practical implications The study has implications for Indian banks given the high level of losses due to bad loans, and the implementation of Basel III norms by the central bank, i.e. Reserve Bank of India. Social implications The study has implications for Indian financial system as a large percentage (about 33 per cent) of household savings are deployed in deposits with commercial banks and other financial institutions. The bank failure(s) can have disastrous consequences for the Indian economy as the capacity of the Indian financial system to withstand such shocks is highly doubtful. Originality/value There is very little evidence on ORM practices of Indian banks, and its relationship with size and ownership. The study assumes significance in the context of significant changes in the institutional and regulatory framework.

A rheological behavior of various polyvinylidene difluoride binders for high capacity LiNi0.6Mn0.2Co0.2O2

Various polyvinylidene difluorides (PVDF) as polymeric binding agent in lithium‐ion battery were rheologically evaluated on high capacity and excess lithium‐LiNi0.6Mn0.2Co0.2O2 (Ni‐rich NMC). We found that the suspension polymerized PVDF binder is more stable upon gelation for long duration while other high molecular weight PVDF binders (MW &gt; 900,000) show irreversible rheological transformation that can dramatically compromise the coating step during lithium‐ion battery electrode slurry preparation. POLYM. ENG. SCI., 56:760–764, 2016. © 2016 Society of Plastics Engineers

Reinforcement and mud-pumping benefits of geosynthetics in railway tracks: Numerical analysis

Laboratory tests were conducted on track materials to evaluate constitutive parameters for three different sets of constitutive relationships, namely, non-linear analysis, straight analysis and coupled analysis. The model test results of finite element analyses using various constitutive relationships are compared. The coupled analysis provided a better prediction of the measured results compared to the non-linear and straight analyses. A detailed parametric study of a prototype track was then performed using the coupled analysis to evaluate the effects of geosynthetics on track reinforcement and mud-pumping reduction.Geogrid reinforcement was found to significantly reduce tie displacement only at low subgrade modulus values and effective subgrade shear strength parameters. Geogrid reinforcement was equally effective at reducing tie displacement within the subballast thickness range of 450–1000 mm. High excess pore water pressure coupled with low effective cohesion gives rise to mud-pumping problems in silty soil subgrades. The provision of geotextiles at the subgrade surface facilitates quick in-plane drainage and dissipation of pore water pressure. Thus, excess pore water pressure was observed to be lower in a geotextile-stabilized track compared to that in an unreinforced track, indicating reduction in mud-pumping potential in the former.

Os and U–Th isotope signatures of arc magmatism near Mount Mazama, Crater Lake, Oregon

Interaction of mantle melts with the continental crust can have significant effects on the composition of the resulting melts as well as on the crust itself, and tracing this interaction is key to our understanding of arc magmatism. Lava flows and pyroclastic deposits erupted from ∼50 to 7.7 ka at Mt. Mazama (Crater Lake, Oregon) were analyzed for their Re/Os and U–Th isotopic compositions. Mafic lavas from monogenetic vents around Mt. Mazama that erupted during the buildup to its climactic eruption have lower 187Os/188Os ratios (0.1394 to 0.1956) and high 230Th excess ((230Th/238U)0 of 1.180 to 1.302), whereas dacites and rhyodacites tend to have higher 187Os/188Os ratios (0.2292 to 0.2788) and significant 238U excess ((230Th/238U)0 of 0.975 to 0.989). The less radiogenic Os isotope compositions of the mafic lavas can be modeled by assimilation of young (∼2.5 to 7 Ma), mafic lower crust that was modified during regional extension, whereas the more radiogenic Os isotope compositions of the dacites and rhyodacites can be attributed to assimilation of older (∼10 to 16 Ma), mid to upper crust that acquired its composition during an earlier period of Cascade magmatism. Production of Th excesses in the lower crust requires very young garnet formation accompanying dehydration melting in the lower crust at less than a few 100 ka by heat from recent basaltic magma injection. The results from this study suggest that the combination of Os and Th isotopes may be used to provide insights into the timescales of evolution of the continental crust in arc settings, as well as the influence of the crust on erupted magmas, and suggest a link between the age and composition of the lower and upper crust to regional tectonic extension and/or earlier Cascade magmatism.