Gradation-based framework for asphalt mixture

Aggregates are the major component of asphalt mixtures, greatly influencing the mixtures resistance to failure. The structure that is formed by the aggregates will depend mostly on the size distribution, shape and mineral composition. Coarse aggregate have a strong influence on the resistance to rutting, while fines provide stability to the mixture. In the present study a generalized framework is developed to identify the range of aggregate sizes which form the load carrying structure in hot mix asphalt and determine its quality. The method has been developed as a numerical procedure based on packing theory. Parameters like porosity and coordination number have been used to evaluate the quality of the load carrying structure and relate it to resistance to rutting. The framework has been evaluated on several field and laboratory mixtures and related to their rutting performance. The gradation analysis of the mixtures has compared favorably with the performances reported from the field and laboratory testing. The developed gradation analysis framework has proven to be a tool to identify those mixtures with a poor rutting performance based on the gradation of the aggregates.     

évaluation du traitement des traits perceptifs des concepts vivants et non vivants lors du vieillissement normal et de la maladie d'Alzheimer.

The purpose of this study is to examine whether the way in which adults process animate and inanimate objects is impacted by the distinctiveness of the object and whether processing ability varies with age and with the quality of aging (e.g. normal aging versus pathological aging). We examined the perceptual functioning of young adults, elderly subjects and patients suffering from Alzheimer's disease. Generally, the results do not support the distributed model of conceptual representation. However, they do demonstrate that the ability to recognize objects by their distinctiveness is affected by normal and pathological aging. A gradual deterioration in the ability to correctly perceive animate objects was also observed as pathological aging progressed. These results, as well as our methods of assessing semantic memory, are discussed in terms of their theoretical and practical implications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Model of fracture for the Zry cladding of nuclear fuel rods included in the code DIONISIO 1.0

The DIONISIO code describes most of the main phenomena occurring in a fuel rod during normal operation of a nuclear power reactor. Starting from the irradiation history, the code predicts the temperature distribution, elastic and plastic stress and strain, creep, swelling and densification, release of fission gases, caesium and iodine to the internal rod volume, gas mixing, pressure increase, irradiation growth of the cladding, development of an oxide layer on its surface and hydrogen uptake, restructuring and grain growth in the pellet.This work presents the model of Zircaloy fracture included in the code DIONISIO 1.0. The model of pellet-cladding mechanical interaction (PCMI) provides the forces caused by the solid-solid contact which add to the changing internal pressure and to the constant external pressure. Besides, the program evaluates the effects of a corrosive atmosphere (stress corrosion cracking, SCC) internal or external. With these data, the code calculates the J integral around the tip of an initiated crack, and proceeds to analyze, according to the quantity of corrosive substance dissolved and the cladding stress field, if the crack remains unchanged, if it grows due to the I-SCC mechanism, or if propagation is ductile, following the R curve of the material.Results corresponding to different PHWR and PWR reactors are presented and compared with code results. In particular, good agreement is obtained in the simulation of MOX experiments, where the cladding failed due to propagation of cracks originated in SCC.     

Cloud point and solvent extraction study of uranium(VI) by 8‐hydroxyquinoline

BACKGROUND: Cloud point extraction (CPE) is an attractive alternative to solvent extraction. However, comparisons between both techniques are lacking. In this paper, the extraction of uranium(VI) using 8‐hydroxyquinoline (HQ) as chelating agent was studied by CPE using Triton X‐114 as non‐ionic surfactant and by solvent extraction using CHCl₃ as diluent. RESULTS: Using CPE, a quantitative extraction was observed for pH higher than 4.5 with a HQ/U ratio of 10. Using solvent extraction an increase in the HQ/U ratio up to 50 is necessary to obtain a near quantitative extraction. Both extraction systems were then compared with respect to the nature of extracted species, and the extraction constants determined using log‐log analysis of the extraction data. In the solvent extraction system, the extracted species were identified as UO₂Q₂ and the corresponding extraction constant was found to be log k_ex = ? 3.6 ± 0.2 on the molar scale. Considering that UO₂Q₂ is also the extracted species in CPE, a slightly higher extraction constant, i.e. log k_ex = ? 2.5 ± 0.3, was found. CONCLUSION: Such a small difference in favour of the CPE system may arise from the combination of various phenomena, including effects of temperature and effects of ‘extractant environment’. However, a change in the nature of the extracted species, namely from UO₂Q₂ in the solvent extraction system to the formation of adducts, i.e. UO₂Q₂(HQ) and UO₂Q₂(HQ)₂ in the CPE system, due to higher HQ concentration in the surfactant‐rich phase compared with chloroform, cannot be precluded, but requires confirmation. Copyright © 2012 Society of Chemical Industry     

Influence of Bias Parameters and Plasma Density on Vacuum Arc Macroparticle Accumulation

Several regularities of the accumulation of vacuum arc metal macroparticles (MP) on the sample on repetitively pulsed biasing (10⁵ Hz, 7 µs, ?0.5 kV to ?3.5 kV) have been investigated. It has been shown that the substrate temperature plays a very important role in controlling the MP amounts on the sample. A possibility to change the metal particle number density on the substrate in the range from 10⁵/cm² to 10⁷/cm², depending on bias pulse parameters, sample temperature, and ion plasma saturation current density, has been demonstrated. The shape of MPs and their adhesion to the substrate surface depends strongly on the MP energy balance in a high-voltage space charge sheath.     

Challenging Hurdles of Current Targeting in Glioblastoma: A Focus on Immunotherapeutic Strategies

Glioblastoma is the most frequent primary neoplasm of the central nervous system and still suffers from very poor therapeutic impact. No clear improvements over current standard of care have been made in the last decade. For other cancers, but also for brain metastasis, which harbors a very distinct biology from glioblastoma, immunotherapy has already proven its efficacy. Efforts have been pursued to allow glioblastoma patients to benefit from these new approaches, but the road is still long for broad application. Here, we aim to review key glioblastoma immune related characteristics, current immunotherapeutic strategies being explored, their potential caveats, and future directions.     

Action compatibility effects are hedonically marked and have incidental consequences on affective judgment.

Recent results from Cannon, Hayes, and Tipper (2010) have established that the Action Compatibility Effect (ACE) is hedonically marked and elicits a genuine positive reaction. In this work, we aim to show that the hedonic marking of the ACE has incidental consequences on affective judgment. For this, we used the affective priming paradigm principle (for a review, see Musch & Klauer, 2003): participants have to respond, as quickly as they can, regarding the pleasantness or unpleasantness character of a target word. In the priming phase, we do not present an affective stimulus; however, we present two different graspable objects, one after the other. The handles of the graspable objects are shown either both on the same side (i.e., perceptual action compatibility) or not (i.e., perceptual action incompatibility). In addition, the orientation of the handles of the objects are either compatible (i.e., action compatibility) or not (i.e., action compatibility) with the response hand used for the word evaluation. Consistent with our hypothesis, participants responded faster to positive words after perceptual action compatibility and action compatibility (thus demonstrating the ACE) than after incompatibility conditions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Determining factors of thermoelectric properties of semiconductor nanowires

It is widely accepted that low dimensionality of semiconductor heterostructures and nanostructures can significantly improve their thermoelectric efficiency. However, what is less well understood is the precise role of electronic and lattice transport coefficients in the improvement. We differentiate and analyze the electronic and lattice contributions to the enhancement by using a nearly parameter-free theory of the thermoelectric properties of semiconductor nanowires. By combining molecular dynamics, density functional theory, and Boltzmann transport theory methods, we provide a complete picture for the competing factors of thermoelectric figure of merit. As an example, we study the thermoelectric properties of ZnO and Si nanowires. We find that the figure of merit can be increased as much as 30 times in 8-Å-diameter ZnO nanowires and 20 times in 12-Å-diameter Si nanowires, compared with the bulk. Decoupling of thermoelectric contributions reveals that the reduction of lattice thermal conductivity is the predominant factor in the improvement of thermoelectric properties in nanowires. While the lattice contribution to the efficiency enhancement consistently becomes larger with decreasing size of nanowires, the electronic contribution is relatively small in ZnO and disadvantageous in Si.