Finite Point Low Mach Number Algorithm for Unsteady Nonisothermal Flows Application to the Study of Reactive Flow Past a Thin Catalytic Wire

A numerical algorithm is presented for the solution of low Mach number unsteady nonisothermal flows at moderate Reynolds numbers (Re ～ 100) with variable transport properties. The low Mach number limit is approached by using a relaxation method of the pseudo-compressibility type that has proved to be numerically robust and accurate enough to be used in industrial applications. Time integration is explicit and space integration is based on a finite point approach. Solver validation includes a sensitivity analysis and a comparison with previously published results concerning the flow around heated cylinders at different Re and temperature loadings. Then, the solver is applied to calculate the flow of a reacting mixture past a thin catalytic wire, a problem of interest for power MEMS design (micro catalytic reactors), aiming to determine the chemical-to-thermal energy conversion rate at the catalytic wire.     

Evaluation of heat and oxidative damage during storage of processed tomato products. II. Study of oxidative damage indices

Tomato products (pulp, puree and paste) submitted to accelerated aging (30, 40 and 50 °C for 3 months) were studied to evaluate variations in the kinetics of the degradation of antioxidants and antioxidant activity. The carotenoids lycopene and β‐carotene, ascorbic acid, rutin and total phenolics were analysed. The antioxidant activity was measured using (a) the xanthine oxidase (XOD)/xanthine system, which generates superoxide radicals and hydrogen peroxide, and (b) the linoleic acid/CuSO₄ system, which promotes lipid peroxidation. The ascorbic acid content decreased even at 30 °C, following pseudo‐first‐order kinetics, with an activation energy of 105 200 J mol^?1 for tomato pulp and 23 600 J mol^?1 for tomato paste. The lower the initial ascorbic acid content, the higher was the degradation rate. Variations in phenolic compounds occurred at 40 °C and higher, following pseudo‐zero order kinetics. The antioxidant activity of the hydrophilic fraction of the tomato products depended on both antioxidant degradation and the Maillard reaction and could not be described by a kinetic model. The β‐carotene content decreased even at 30 °C, whereas the lycopene content was stable in all samples. The antioxidant activity of the lipophilic fraction of the tomato products decreased following pseudo‐first order kinetics, with an activation energy of 22 200 J mol^?1 for tomato pulp and 20 200 J mol^?1 for tomato paste. It is concluded that significant ‘oxidative damage’ can occur in tomato products during their commercial shelf‐life. Copyright © 2003 Society of Chemical Industry     

Extending the shelf-life and proximate composition stability of ready to eat foods in vacuum or modified atmosphere packaging

The stability of the proximate composition (moisture, proteins, lipids and ash) and the microbiological state of cooked ‘ready to eat’ foods in vacuum or modified atmosphere packaging were examined and compared with conventionally packaged (in air) foods. The study was carried out for 7 and 29 days, during which time the food products were stored at 3°C. Vacuum or modified atmosphere packaging were effective for prolonging the shelf-life of the studied products up to 29 days with minimal changes in the proximate composition. Aerobic mesophilic, psychrotrophic microrganisms, and yeasts and moulds increased with time regardless of packaging type but more rapidly under conventional packaging.     

Improving the control of food production in catering establishments with particular reference to the safety of salads

Food production in four school kitchens was checked in order to improve food safety by establishing a self-regulated control system based on good manufacturing practices (GMPs) and as an introduction to hazard analysis and critical control points (HACCP). A form, which referred to different aspects such as the cleanliness of the installations, personnel hygiene and the prevention of cross-contamination, was used to obtain the necessary data. Furthermore, foods thought to be of high risk were periodically collected for microbiological analysis. Samples for microbiological examination were taken from cutting boards, tables, machines, knives and ingredients (on-line sampling). We used the results as a basis to train foodhandlers to improve the safety of salad preparation, in accordance with GMPs, observing that hygiene improvement depended on chlorine levels in the rinsing water. We also designed several controls for raw materials, cold storage, freezers and available chlorine levels in water. At the end of the study period, we observed a decrease in microbial populations of examined samples, which indicated that the knowledge of hygiene practices on the part of foodhandlers represents a critical control point, as defined by the EC Directive 93/43/EEC on Hygiene of Food Stuffs.     

Physicochemical Investigation of the Reaction of Components of the Si — Al — O — N — Ti System in the Si3N4 — Al2O3 — AlN — SiO2 — TiN — TiO2 Region. Part 2. Subsystems Si3N4 — AlN,TiN — AlN,Al2O3 — AlN

The reaction of components of the Si — Al — O — N — Ti system in its elements Si ₃N₄ — AlN, TiN — AlN, and Al ₂O ₃ — AlN was investigated by differential thermal and x-ray diffraction analysis. It was established that upon hot pressing mixtures of Si₃N ₄ and AlN (up to 1950°C) free silicon is formed by the decomposition of Si ₃N₄, which reacts with oxygen present as an impurity to form SiO. When TiN reacts with AlN a phase with the spinel structure (Al₂₃O ₂₇N ₅), which can form only in the presence of excess oxygen, appears in addition to the initial components. Spinel is also produced by the reaction of Al ₂O₃ with AlN. In this case a eutectic between Al ₂₃O₂₇N₅ and Al₂O₃ is observed.     

Analysis of quality-of-service in a wide-area interactive distance learning system

Interactive distance learning (IDL) is an evolving paradigm of instruction and learning that attempts to overcome both distance and time constraints found in traditional classroom learning. The electronic classrooms at two sites of the University of Oslo and two further sites in Norway overcome separations in space by exchanging digital audio, video, and whiteboard information via the Norwegian academic ATM-based network Supernett II. The electronic classrooms are used since 1993 for teaching graduate level courses. This paper presents measurements and analysis results of transport, application, and user level Quality-of-Service (QoS) of the electronic classrooms. We describe our general experiences with this system for synchronous IDL. The lessons learned represent the motivation for the ongoing extension to support asynchronous IDL by a multimedia database system (MMDBS) to manage all data used and generated in the electronic classrooms.     

Education reform: Challenges for psychology and psychologists.

National, state, and local education reform agendas have been on a fast track for more than a decade. Although some psychologists have been active in promoting psychology and psychological services in education reform initiatives, knowledge about their efforts is fragmented. In order to educate psychologists about education reform, this article highlights the impetus for the recent education reform movement, briefly reviews the latest waves of education reform, and discusses the development of the National Education Goals. Then, an argument is made for the integration of education, health, and social reform initiatives; state-level education reform principles and initiatives are highlighted, illustrated by the systemic education reform mandate in Kentucky. Next, progress toward the development and implementation of an APA-sponsored response to the National Education Goals is discussed. Finally, objectives and roles for psychologists in advancing education reform are presented, and guidelines for the education and training of future psychologists are introduced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MARKTRAN II: An interactive FORTRAN program for calculating markov transition probabilities of two-dimensional patterns

MARKTRAN II is an interactive FORTRAN IV program that computes Markov transition probabilities for two-dimensional patterns. The pattern is represented by a series of discrete states at each point on a rectangular grid composed of square cells. Transition probabilities in eight directions are computed. MARKTRAN II is useful for numerically describing the fabric of patterns that possess any degree of anisotropy. Geological applications include analysis of rock fabrics, outcrop patterns of geological maps, and variations in ore grade expressed as discrete states.     

Meßverfahren zur Bestimmung von zweiachsigen Eigenspannungsverteilungen über die Werkstückhöhe

Definition von Eigenspannungen. Verfahren zum Nachweis und zur Messung von Eigenspannungen. Vorstellung eines neuen Meßverfahrens zur Bestimmung der Höhenverteilung von Eigenspannungen. Mechanische und spannungsoptische Modellversuche. Anwendung des Meßverfahrens auf Schweißeigenspannungen.