Control of interface reactions in SIC/TI composites

The reaction between a 0.5 to 1.0 Al film and a thick Ti substrate to form TiAl3 occurs very rapidly on heating to 635 C and causes the Al to be confined to the surface region. After heating to 900 C Ti3Al is formed with little release of Al into alpha Ti. Further annealing at 900 C eventually causes the Ti3Al phase to decompose and a substantial amount of Al is released into alpha Ti. The interdiffusion coefficient for Al in alpha Ti at 900 C increases by less than one order of magnitude as Al is varied from 0 to 20 at %. These data were obtained from the (101) X-ray diffraction intensity band using polycrystalline samples. Improvements in the analysis of X-ray diffraction data for the determination of composition profiles are discussed

High Pressure Processing Applications in Plant Foods

High pressure processing (HPP) is a cold pasteurization technology by which products, prepacked in their final package, are introduced to a vessel and subjected to a high level of isostatic pressure (300–600 MPa). High-pressure treatment of fruit, vegetable and fresh herb homogenate products offers us nearly fresh products in regard to sensorial and nutritional quality of original raw materials, representing relatively stable and safe source of nutrients, vitamins, minerals and health effective components. Such components can play an important role as a preventive tool against the start of illnesses, namely in the elderly. An overview of several food HPP products, namely of fruit and vegetable origin, marketed successfully around the world is presented. Effects of HPP and HPP plus heat on key spoilage and pathogenic microorganisms, including the resistant spore form and fruit/vegetable endogenous enzymes are reviewed, including the effect on the product quality. Part of the paper is devoted to the industrial equipment available for factories manufacturing HPP treated productsinfo:eu-repo/semantics/publishedVersio

Content Analysis of Drug Offenders\u27 Sketches on the Draw-an-Event Test for Risky Sexual Situations

Objectives: To evaluate the utility of the Draw-an-Event Test for risky sexual situations (DET-RS), a nonverbal memory-based assessment tool used for productions of spontaneous content associated with risky sex. Methods: Traditional holistic coding analysis of 298 drug offenders\u27 content productions. Results: Content analyses of DET-RS sketches provided increased understanding of substance use and other context preceding risky sexual situations with different types of sex partners. None of the sketches including drugs depleted condoms, only one of the sketches with alcohol included a condom, and only 2 sketches mentioned sexually transmitted diseases. Conclusions: The DET-RS is a useful research tool for generating nonverbal context-specific stimuli associated with risky sexual situations

A Set-Theoretic Method for Verifying Feasibility of a Fast Explicit Nonlinear Model Predictive Controller

In this chapter an algorithm for nonlinear explicit model predictive control is presented. A low complexity receding horizon control law is obtained by approximating the optimal control law using multiscale basis function approximation. Simultaneously, feasibility and stability of the approximate control law is ensured through the computation of a capture basin (region of attraction) for the closed-loop system. In a previous work, interval methods were used to construct the capture basin (feasible region), yet this approach suffered due to slow computation times and high grid complexity. In this chapter, we suggest an alternative to interval analysis based on zonotopes. The suggested method significantly reduces the complexity of the combined function approximation and verification procedure through the use of DC (difference of convex) programming, and recursive splitting. The result is a multiscale function approximation method with improved computational efficiency for fast nonlinear explicit model predictive control with guaranteed stability and constraint satisfaction

Some emerging x-ray diffraction techniques of interest to metallurgists

Avances recientes en el procesamiento de datos de difracción de rayos X permiten duplicar la resolución de los resultados. La segunda derivada posibilita distinguir el número de máximos de difracción sobrepuestos en un diagrama complejo, lo cual proporciona importante información para un análisis computacional de mínimos cuadrados no lineales. Este tratamiento utiliza la función Pearson VII, lo que permite determinaciones de fases cualitativas y cuantitativas, usando diagramas de difracción que normalmente serian descartados. Se muestran ejemplos de aplicación a diagramas tomados a minerales de cobre chilenos. Otro avance reciente se relaciona con la determinación cuantitativa de fases por difracción de rayos X en materiales con texturas marcadas. Esto se puede aplicar a la determinación de austenita retenida, así como también a otros problemas de multifases, donde la textura impide un análisis cuantitativo exacto. Se describe una tercera técnica, que permite obtener información sobre difusión en zonas de 1/10 del tamaño requerido por las técnicas convencionales. Debido a la dependencia del perfil del espaciado interplanar, de su primera derivada, muestra implícitamente un alto grado de sensibilidad con respecto a las técnicas usuales para medir directamente la composición. Proporciona así, una ventaja adicional al entregar información sobre las estructuras cristalinas en las zonas de difusión

Environmental effects on advanced composites

The development of titanium matrix composites for elevated temperature applications was investigated. General solutions for treating diffusion in multiphase multicomponent systems were studied. Graphite polyimide composites were characterized with respect to mechanical property degradation by moisture