Microstructure and formation mechanism of complex chromium diffusion layer

Presentation of a new type of chromium diffusion layer obtained on 0.5 % C carbon steel by termit process. Microstructure, phase composition and chemical composition of the layer obtained after various chromizing conditions. Determination of the growth mechanism of layer based on Fe-Cr-C equilibrium diagrams.     

Data errors in the computation of free motion

Input data in the computation of free motion (the inertia and stiffness matrices) contain some errors. These errors generate errors of output data (the natural frequency vector, the natural mode vectors). In this paper the relationships between errors of input and output data in the computation of free motion are derived. This analysis is applied to the finite element method. The paper presents program ERROR, which computes the errors of the natural frequencies created by the inertia matrix errors. An example of the influence of the errors of the mass and of the mass moment of inertia on the natural frequencies of a ship hull is presented.     

A novel extraction method for peanut allergenic proteins in chocolate and their detection by a liposome-based lateral flow assay

In this study, conditions for extracting the major peanut allergen (Ara h1) from chocolate were optimized, and the extracted samples were analyzed by a lateral flow assay (LFA) using liposomal nanovesicles. The optimal conditions using peanut-spiked chocolate were found to be extraction with a mixture of phosphate buffered saline and hexane for 30 min at 35 °C. After centrifugation, the buffer portion was treated with insoluble poly(vinylpolypyrrolidone) to remove phenolic compounds, and then analyzed by the LFA. The entire analysis, including sample preparation and LFA, could be easily completed within 2 h, and the detection limit was 158 g of peanuts/g of chocolate.     

The Influence of Oxide Scale on Heat Transfer during Reheating of Steel

The present work presents methodology and development of a mathematical model for prediction of the influence of oxide scale on heat transfer during reheating of steel in an industrial furnace. In this developed model, temperatures inside the steel billet were measured and with thermocouples at selected places and were collected by a water cooled computer that was traveling inside the slab. CFD is used to calculate the flow field inside of a furnace. The mass‐transfer coefficient of the scale formation is obtained by solving the convection mass‐diffusion equation across a boundary layer to the surface of a flat plate. A model for inverse heat conduction is employed to calculate the local surface temperature and heat flux on top of the growing oxide scale layer on a slab moving through a walking beam reheating furnace. By using the inverse method, the transient temperature and heat flux was firstly determined on the surface of the steel. During subsequent computations, the growth of the scale was calculated and the surface temperature of the oxide scale was extracted by using the Cauchy data from the previous calculations. The sensibility of the model on steel physical parameters is studied, and suitable parameters were obtained for heating a low carbon steel plate in the reheating furnace. Results show that the oxide scale layer should not be neglected in reheating models.     

Influence of operation conditions on true-static DC characteristics and on electro-thermal transient states in silicon carbide Merged PiN Schottky diodes.

In this paper, measured and calculated non-isothermal DC characteristics of silicon carbide MPS devices are investigated, with special attention paid on critical parameters, such as maximum current and junction temperature at which a thermal runaway may occur. Electro-thermal transient states in single MPS devices (forward surge current tests) and in the simple Greatz rectifier are simulated and compared to measurements. Various electro-thermal models of SiC SBDs, with a simplified, effective procedure for calculations of junction temperature are proposed.     

What is failure? An approach to constructive negation

A standard approach to negation in logic programming is negation as failure. Its major drawback is that it cannot produce answer substitutions to negated queries. Approaches to overcoming this limitation are termed constructive negation. This work proposes an approach based on construction offailed trees for some instances of a negated query. For this purpose a generalization of the standard notion of a failed tree is needed. We show that a straightforward generalization leads to unsoundness and present a correct one.The method is applicable to arbitrary normal programs. If finitely failed trees are concerned then its semantics is given by Clark completion in 3-valued logic (and our approach is a proper extension of SLDNF-resolution). If infinite failed trees are allowed then we obtain a method for the well-founded semantics. In both cases soundness and completeness are proved.     

Strict completion of Logic Programs

The paper presents a new approach to the problem of completeness of the SLDNF-resolution. We propose a different reference theory that we call strict completion. This new concept of completion (comp^*(P)) is based on a program transformation that given any program transforms it into a strict one (with the same computational behaviour) and the usual notion of program completion. We consider it a reasonable reference theory to discuss program semantics and completeness results. The standard 2-valued logic is used. The new comp^*(P) is always consistent and the completeness of all allowed programs and goals w.r.t. comp^*(P) is proved.     

The theoretical and experimental investigation of the phase-change solar thermosyphon

The paper is concerned with the study of two-phase solar thermosyphon for domestic hot water (SDHW). Due to a combination of ideas of the heat pipe and classical thermosyphon, the heat transfer in the proposed installation is to be realised by the liquid - gas phase change, what should increase significantly both the heat efficiency of the system and the system applicability.     

Evaluation of kinetic parameters of coal ignition

A method is presented of evaluating the kinetic parameters for the ignition reaction of coal based on the Semenov's thermal ignition theory adopted to coal particle ignition. The evaluated apparent activation energy, E, for bituminous coal, anthracite and bituminous coal char are in the range 46–103 kJ mol^?1. A verification was made by comparing the measured induction periods for the coal particles with those calculated numerically. The oxidation rate is controlled by diffusion into pores.