An electron microscopic and diffraction study of Cu-9 wt pct Al alloy

An electron microscopic investigation of Cu-9 wt pct Al alloy low thermal treated at 250°C for 30 min was performed in the deformed and non-deformed condition. For this composition and ordering treatment the alloy exhibits the higher increase in strength. It was found that the images formed in the non-deformed alloy, reveal the presence of ordered domains of an average size of 80?, being the amount of order dependent of whether or not quenched-in vacancies are present. It is probable that the domains nucleate preferentially at stacking faults in the deformed condition. A periodic antiphase structure was determined from computations and comparison with electron diffraction data. The superlattice cell is based on the LI₂ type, tetragonal face centered with a period approximately three times the lattice parameter of the matrix, having three variants of orientation within an ordered region.     

Entropy of partially polarized light and application to statistical processing techniques

We have analyzed entropy properties of coherent and partially polarized light in an arbitrary number of spatial dimensions. We show that for Gaussian fields, the Shannon entropy is a simple function of the intensity and of the Barakat degree of polarization. In particular, we provide a probabilistic interpretation of this definition of the degree of polarization. Using information theory results, we also deduce some physical properties of partially polarized light such as additivity of the entropy and depolarization effects induced by mixing partially polarized states of light. Finally, we demonstrate that entropy measures can play an important role in segmentation and detection tasks.     

Behavior of Ga,In, Sn,and Te in Copper Matte Smelting

Metallurgical and Materials Transactions B - The distributions of Ga, In, Sn, and Te between copper-iron mattes and silica-saturated iron silicate slags over a wide range of matte grades 55 to 75...     

Spinal TRPA1 Contributes to the Mechanical Hypersensitivity Effect Induced by Netrin-1

Netrin-1, a chemoattractant expressed by floor plate cells, and one of its receptors (deleted in colorectal cancer) has been associated with pronociceptive actions in a number of pain conditions. Here, we addressed the question of whether spinal TRPC4/C5 or TRPA1 are among the downstream receptors contributing to pronociceptive actions induced by netrin-1. The experiments were performed on rats using a chronic intrathecal catheter for administration of netrin-1 and antagonists of TRPC4/C5 or TRPA1. Pain sensitivity was assessed behaviorally by using mechanical and heat stimuli. Effect on the discharge rate of rostral ventromedial medullary (RVM) pain control neurons was studied in lightly anesthetized animals. Netrin-1, in a dose-related fashion, induced mechanical hypersensitivity that lasted up to three weeks. Netrin-1 had no effect on heat nociception. Mechanical hypersensitivity induced by netrin-1 was attenuated by TRPA1 antagonist Chembridge-5861528 and by the control analgesic compound pregabalin both during the early (first two days) and late (third week) phase of hypersensitivity. TRPC4/C5 antagonist ML-204 had a weak antihypersensitivity effect that was only in the early phase, whereas TRPC4/C5 antagonist HC-070 had no effect on hypersensitivity induced by netrin-1. The discharge rate in pronociceptive ON-like RVM neurons was increased by netrin-1 during the late but not acute phase, whereas netrin-1 had no effect on the discharge rate of antinociceptive RVM OFF-like neurons. The results suggest that spinal TRPA1 receptors and pronociceptive RVM ON-like neurons are involved in the maintenance of submodality-selective pronociceptive actions induced by netrin-1 in the spinal cord.     

Mixing Rules with Complex Dielectric Coefficients

This article discusses the determination of effective dielectric properties of hetereogeneous materials, in particular media with lossy constituents that have complex permittivity parameters. Several different accepted mixing rules are presented and the effects of the structure and internal geometry of the mixture on the effective permittivity are illustrated. Special attention is paid to phenomena that the mixing process causes in the character of the macroscopic dielectric response of the mixture when the losses of one or several of the components are high or when there is a strong dielectric contrast between the component permittivities.     

Response of steel-concrete composite panels to in-plane loading

Steel-Concrete Composite (SCC) panels consist of steel faceplates with welded shear studs and concrete infill. The shear studs, which perform a similar function to bond of rebars in reinforced concrete, act as springs resisting the shear slip between the faceplates and concrete. In spite of extensive research in the 1980s and 1990s due to the interest in using SCC in offshore construction and in nuclear power plants, and recently related Codes, there is no analytical method to-date to predict the shear studs response to in-plane loading. Shear connectors are sized according to various criteria unrelated to their actual forces under in-plane loads, such as prevention of faceplate buckling or out-of-plane shear resistance. This paper presents a closed analytical solution of the equilibrium and compatibility differential equations for steel and concrete displacements of SCC panels, based on distributed shear springs idealization. Analytical results presented in this paper are validated by test results of SCC panels loaded by pure shear forces and can be used as practical design formulas for the in-plane portion of the design loads.     

Exposure to Pesticides by Medium and Route: The 90th Percentile and Related Uncertainties

Multiple route, multiple media distributions of exposure to chlorpyrifos and diazinon and associated uncertainties are investigated using the database generated by the National Human Exposure Assessment Survey in Arizona (NHEXAS-AZ). Exposure to pesticides and associated uncertainties may be estimated using either deterministic or probabilistic methods. This paper employs probabilistic models to estimate the 90th percentile of inhalation, dietary ingestion, dermal, and nondietary ingestion exposures to chlorpyrifos and diazinon. Questions associated with the uncertainty of exposure estimates for the two pesticides are also investigated. Probabilistic models are used to formulate distributions of exposures to each of the two pesticides for several subpopulation groups. Parameter uncertainties associated with the 90th and other percentiles of population and subpopulation groups are addressed in this paper. Highly exposed subpopulations have been defined as those with route-specific 90th percentile exposure that is higher than the population 90th percentile. All subjects exposed to levels above the 90th percentile of inhalation exposure live in dwellings with carpeting covering over 50% of their floor areas. The relative uncertainty of the 90th percentile of dermal exposure is larger than corresponding uncertainties for inhalation, dietary ingestion, and nondietary exposure.