Experimental study of phase equilibria in the system PbO-ZnO-SiO2

An experimental study on the ternary system PbO-ZnO-SiO₂ in air by high-temperature equilibration and quenching techniques followed by electron probe X-ray microanalysis was carried out as part of the wider research program on the six-component system PbO-ZnO-SiO₂-CaO-FeO-Fe₂O₃, which combines experimental and thermodynamic computer modeling techniques to characterize zinc and lead industrial slags. Liquidus and solidus data were reported for all primary phase fields in the system PbO-ZnO-SiO₂ in the temperature range 640 °C to 1400 °C (913 to 1673 K).     

Methods of multifactor damage risk management in automated information systems

This paper describes one method used for risk assessment and determines the direction of further research in this field.     

A composite fitting model of discrete handbook data for peripheral end milling

Machining data handbooks are important reference books in the machining industry, as they provide recommended process parameter values for common machining operations. The machining data, although covering a wide range of relevant cutting conditions, are only listed under discrete cutting conditions. Rough interpolation-based calculations are often needed in order to estimate the process parameter values at the desired cutting condition. In this work, a composite fitting model is presented to fit a composite functional curve through the discrete handbook data of recommended cutting speeds and feeds with respect to the cutting condition of radial depth of cut for peripheral end milling. The objective is to establish a functional relationship from the handbook data such that recommended cutting speed and feed can be obtained for any given radial depth of cut. According to the tabulated layout of the machining data, the entire range of the radial depth of cut is divided into three segments having distinctive formulations and trends. Constraints are then imposed to preserve the trends and smoothly connect the adjacent segments. As a possible application of the presented model, a case study of machining a rectangular pocket is provided. Machining time of a potential process plan is readily evaluated based on the cutting speeds and feeds obtained from the composite model.     

On modeling of processes of moisture circulation and electric charge separation in the atmosphere

The possibilities of obtaining water and electric energy from the atmosphere by means of simulation of the local atmospheric moisture cycle as well as electrical phenomena which accompany it in both natural and laboratory conditions are discussed. The basic possibility of achieving these goals according to the natural analogy is shown experimentally.     

Extension of thick-walled cylindrical anisotropic blanks,with thinning of the wall

The stress-strain state of thick-walled anisotropic cylindrical blanks during extension with wall thinning is considered. The forces acting on the blanks and the limiting shape changes are investigated.     

Performance of laser polishing in finishing of metallic surfaces

Laser polishing is presently regarded as one of the enabling technologies hoped to eventually replace the need for time-consuming and error-prone manual polishing operations which are often required by metallic surfaces. During laser polishing, a thin layer of material is being melted as a result of laser irradiation. Since molten metal is characterized by increased relocation capabilities, laser polishing is generally accompanied by a more or less significant decrease in the surface roughness. The primary objective of this study is to present a comprehensive snapshot of the advancements made over more than one decade with respect to theoretical and experimental investigation of laser polishing technology. However, in addition to the usual review of the state-of-the-art in the field, the study places an increased emphasis on the finishing performance of the process, defined through the perspective of pre- and postpolishing surface roughness. The implementation of this metric with strong practical implications has revealed that under appropriate process parameters, certain classes of metallic materials can reduce their average surface roughness by more than 80 %, possibly to R _a ?=?5 nm. Nonetheless, a more rigorous and fundamental understanding of the intrinsic mechanisms underlying laser polishing remains one of the currently unfulfilled premises toward a wider industrial adoption of the process.     

Binding of aroma compounds with legumin. III. Thermodynamics of competitive binding of aroma compounds with 11S globulin depending on the structure of aroma compounds

This paper considers the prominent features in competitive binding of aroma esters from their mixtures to 11S globulin of broad beans (legumin) in aqueous medium at pH 7.2 and ionic strength of 0.05 mol dm⁻³. Series of alkyl acetates (C₄–C₈) and methyl esters of carbonic acids (C₅–C₉), differing in the length of hydrocarbon chain, have been under our studying. To accomplish the ends of the study, a combination of ultrafiltration and gas–liquid chromatography (GC) has been used. An increase in the length of hydrocarbon chain of the aroma esters brought about greater binding affinity for the protein, the occurrence of some structural restrictions in the interior of the protein molecule, preventing binding, and the change in the binding mechanism of the aroma compounds at the specific critical length of hydrocarbon chain. Differential scanning microcalorimetry data suggested that the revealed changes in the binding mechanism of the studied aroma compounds were attributable to the conformational modification of the protein globule as a result of binding with the aroma compounds. A distinguishing feature in binding of methyl esters of carbonic acids with legumin was their greater binding affinity for the protein as compared with alkyl acetates. The mutual effect of aroma compounds on binding from their equimolar mixtures to the protein made itself evident, firstly, as a drastic increase in the binding extent of aroma esters, having rather long hydrocarbon chain and, secondly, as a dramatic change in the binding mechanism of the aroma esters with relatively short hydrocarbon chain.     

“Super-overtaking” optimal policies for Markov control processes

In this paper we study the average cost optimization problem for discrete-time Markov control processes on Borel space with possibly unbounded costs. Under proper ergodicity assumptions we show the existence of stationary policies for which asymptotic (as N → ∞) behavior of some functions of N-horizon costs can be better than for overtaking optimal policies.     

Object management in a programming-by-example,parametric, computer-aided-design system

We present the handling of graphical objects in a programming-by-example, CAD system. The object-naming mechanism described here supports the automatic generation of parameter-independent object references in parametric programs. These programs are produced via user interaction during the construction of parametric objects. We use standard programming language control structures and modularity for the parametrisation of variants, repetitive similarities and flexible hierarchical object structure. The object management of parametric entities with varying topology ensures the correctness of their instantiating parametric programs for large domains of parameter values.