Contemporary approaches to certification of measurement provision software

Contemporary approaches to the certification of measurement provision software are considered in domestic and overseas publications. Normative documentation is analyzed and a scheme is proposed for certification that takes account of the features of programs used for metrological purposes. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 65–68, May, 2007.     

Neural Network Feedback Control: Work at UTA’s Automation and Robotics Research Institute

This is an outline of research in neural networks for feedback control done since the mid 1990s at the Automation and Robotics Research Institute (ARRI) of The University of Texas at Arlington (UTA). It shows how the developments of Intelligent Control Systems based on neural networks have followed three main generations. This statement provides a short, broad-brush perspective on the development of intelligent neural feedback controllers.     

IR Radiometry Optical System View Factor and Its Application to Emissivity Investigations of Solid and Liquid Phases

An optical system for fast IR radiometry designed for investigations of thin film thermal properties and pulsed laser melting was analyzed in this work. A methodology for determination of the view factor from calibration measurements was developed. The view factor (0.0255) of the optical system containing two paraboloid mirrors was determined experimentally from calibration measurements on pure metals and metallic alloys. The knowledge of the view factor was then applied to normal emissivity investigations at IR wavelengths. The emissivity of tungsten films prepared by magnetron sputtering was determined for different deposition conditions, varying between 0.036 and 0.071. Liquid phase emissivities of Cu, Mo, Ni, Si, Sn, Ti, and steel were also determined and were found to be higher than solid-state emissivities as predicted from the literature. A knowledge of the liquid-state emissivity of silicon enabled recalculation of the IR signal evolution to the temperature evolution, during and after a nanosecond laser pulse. This was not possible by use of the usual calibration because of silicon’s semi-transparent behavior in the IR range (1–10 μm) in the solid-state phase.     

Technique<Emphasis Type="Italic"> without</Emphasis> theory or theory<Emphasis Type="Italic"> from</Emphasis> technique? An examination of practical,philosophical, and foundational issues in data mining

In this paper, it is argued that although data mining (DM) is being touted as a solution to many business problems and is basking in the glory of electronic business environments of today, as practiced currently, it reflects a preoccupation with short-run commercial applications and a neglect of the underlying theoretical issues. Although an argument can be made that theoretical precedence is not a necessary prerequisite for practical application or for commercial success, it can also be argued that an exclusive reliance on data-driven and exploratory components of pattern recognition without a corresponding attention to the causal schemas underlying patterns is destined to limit the potential for DM to evolve into a long-term solution to business problems or into an intellectual discipline in its own right. This paper presents an overview of key features and assumptions in DM and examines some of the key practical, philosophical, and foundational issues in DM.     

Effect of Annealing in an Active Boron-Containing Medium on Surface Hardening of Nitrided Titanium

We studied the effect of the structural and phase state of surface layers of nitrided VT1-0 titanium on its surface hardening after additional saturation in an active boron-containing atmosphere (900°C, 5 h, 0.1 MPa Ar, a mixture of boron carbide and borax). Additional treatment almost doubles the surface microhardness of the specimens. Surface hardening is a result of both the formation of borides and carbides and the introduction of additional elements into the lattice of titanium nitrides. We established that the formation of a nonstoichiometric nitride with a deficiency of the nonmetallic component prior to additional treatment enables one to reach the maximum effect of surface hardening.     

Surface Position-Resolved Thermophysical Properties for Metallic Alloys

Thermophysical properties are collective measures of a material to transport dynamical quantities of physical nature on its surface or through the bulk. As such, the exact nature of couplings between particles in a many-body assembly of building block atoms or molecules sensitively determines their values. The couplings between nearest neighbors are the product of the local elemental composition and the material phase. In this study, thermal cycling of a four-element Wood’s alloy specimen brings out cadmium-rich patches to the top surface of the specimen. An assembly of such patches leads to depth-dependent deviations of elemental composition from that of the bulk. Surface-layer atoms are driven to form a high temperature laser-produced plasma (LPP), and time-resolved spectroscopy of their emissions show the variability of elemental composition over surface positions as well as over depth from the surface. These thermal history-driven composition anomalies contribute to significant variability in the measured values of spectral emissivity and thermal diffusivity.     

Thermoelastic Contact of a Rotating Inertial Cylinder with a Bush under the Conditions of Friction Self-Oscillations

We construct the solution of the problem of thermoelastic contact of an inertial cylinder with a rigid bush under the conditions of friction heating and wear. It is assumed that the friction coefficient depends on the relative velocity of contacting bodies. We analyze the stability of stationary solutions, determine contact parameters in the process of nonuniform rotation of the cylinder, and demonstrate the possibility of friction self-oscillations.     

Study of defect states in a-Se<Subscript>85</Subscript>Te<Subscript>15−<Emphasis Type="Italic">x</Emphasis></Subscript>Pb<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> thin films by space charge limited conduction mechanism

Current–Voltage (I–V) characteristics have been studied at various temperatures in vacuum evaporated thin films of a-Se₈₅Te_15−x Pb _x (x = 0, 2, 4, 6) alloys. These characteristics show that, at low electric fields, an ohmic behaviour is observed. However, at high electric fields (E ∼ 10⁴ V/cm), the current becomes superohmic. At high fields, in case of samples having 0 and 2 at% of Pb, the experimental data fits well with the theory of space charge limited conduction (SCLC) in case of uniform distribution of localized states in the mobility gap. Such type of behaviour is not observed at higher concentration of Pb in the present glassy system due to high conductivity. In these samples, joule heating due to large currents may prohibit the measurement of SCLC. Using the theory of SCLC for the uniform distribution of the traps, the density of localized defect states near Fermi level is calculated for these compositions. The results indicate that the density of defect states near Fermi level increases on addition of Pb to binary Se₈₅Te₁₅alloy. This is explained in terms of electronegativity of Pb as compared to host elements.     

A Study of the Dust Collection Process in the Production of Refractories

An experimental setup for studying filter-assisted dust collection is described. The role of various factors — hydraulic resistance, filtering velocity, dust concentration, pressure drop, efficiency of recovery — in the performance of filters intended for use in the production of refractory materials is considered. The dust removal method was tested under industrial conditions at the Semilukskii Refractory Plant and can be recommended for wider use in different branches of industry.