On determining the parameters of the kinetic equation of rock durability using the measurement data on tensile strength at different loading rates

The experimental tensile strength data are presented for some hard materials, that are obtained by the three-point bending at different loading rates. Owing to a wide range of change in the loading rates from 10⁻² to 10² MPa/s, constants of Zhurkov’s kinetic equation have been determined. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 11–17, May–June, 2006.     

Purification of Aluminum Nitride Powder with Heat Treatment in Hydrogen

Thermodynamic modelling is provided for heat treatment of AlN powder in a hydrogen atmosphere. According to the results of modelling treatment of AlN containing impurities of O, C, S, Si, Fe, and Ti in a hydrogen atmosphere at a pressure of 0.2 MPa and at 1200–1500 K should lead to purification of nitride from S, Si, and C. It is recommended that purification is not carried out below 1300 K.__________Translated from Poroshkovaya Metallurgiya, Nos. 1–2(441), pp. 112–116, January–February, 2005.     

Determining phase boundaries and vapour/liquid critical points in supercritical fluids: a multi-technique approach

We describe an apparatus used to make precise determinations of the coexistence regimes and critical points of single, binary, and multi-component fluids. The design allows semi-automated measurements to be made over a pressure range of 1–300 bar and a temperature range of−20 to +120 °C with a stability of ±2 mK. We describe the use of the apparatus in determining the critical points and phase boundaries of single component and binary mixtures through a number of optical, acoustic, and shear-mode piezoelectric sensor methods. We conclude that the accurate determination of bubble-point lines, dew-point lines and critical points is best achieved by making measurement using a number of complementary techniques.     

Discovery of Language Resources on the Web: Information Extraction from Heterogeneous Documents

The present article is concerned with the problem of automaticdatabase population via information extraction (IE) from webpages obtained from heterogeneous sources, such as those retrievedby a domain crawler. Specifically, we address the task of fillingsingle multi-field templates from individual documents, a commonscenario that involves free-format documents with the same communicativegoal such as job adverts, CVs, or meeting/seminar announcements.We discuss challenges that arise in this scenario and proposesolutions to them at different levels of the processing of webpage content. Our main focus is on the issue of informationextraction, which we address with a two-step machine learningapproach that first aims to determine segments of a page thatare likely to contain relevant facts and then delimits specificnatural language expressions with which to fill template fields.We also present a range of techniques for the enrichment ofweb pages with semantic annotations, such as recognition ofnamed entities, domain terminology and coreference resolution,and examine their effect on the information extraction method.We evaluate the developed IE system on the task of automaticallypopulating a database with information on language resourcesavailable on the web.     

Transformation kinetics of electric field domains in weakly coupled GaAs/AlGaAs superlattices in a transverse electric field

Transformation kinetics of the resonant-tunneling domain structure in a superlattice in a rapidly varying electric field is investigated using real-time studies of current response. It is shown that the kinetics is mainly determined by a lag in redistribution of the space charge that forms the domain boundary. A nonmonotonic oscillatory dependence of the transient-process duration on the amplitude of a voltage pulse is observed, as well as the effect of the weak dependence of the transformation time on the displacement of the domain boundary, which indicates that the transformation processes is discrete. Possibilities for controlling the switching processes in a multistable system of current states in weakly coupled semiconductor superlattices are discussed.     

Multibody modeling and vibration dynamics analysis of washing machines

In this paper a computational model of a horizontal axis washing machine is presented. The model has been built using a theoretical-experimental methodology consisting of integration of multibody system (MBS) formalism, detailed modeling of machine functional components and experimental data-based validation. The complete model of a washing machine is implemented in the commercial MBS environment Adams/View from MSC.Software. An undesirable impact of washing machine operation on the surroundings is vibration and noise. The impact comes from system dynamics and poorly distributed load inside the drum, creating an imbalance. To get insight into vibration dynamics extensive simulations have been performed for washing machines in service as well as for machines in the developing stage by using the created computational model. This paper presents several results of numerical studies of the vibration dynamics of washing machines including the study of sensitivity of system dynamics with respect to suspension structural parameters, and the results of investigation of the potential of the automatic counterbalancing technology for vibration output reduction. In particular, simulations of the considered two-plane balancing device has shown an existing significant potential in eliminating unbalanced load at supercritical spinning speed, resulting in a substantial vibration reduction in washing machines.     

Polarization‐Sensitive Single‐Wall Carbon Nanotubes All‐in‐One Photodetecting and Emitting Device Working at 1.55 µm

Functional and easy‐to‐integrate nanodevices operating in the telecom wavelength ranges are highly desirable. Indeed, the pursuit for faster, cheaper, and smaller transceivers for datacom applications is fueling the interest in alternative materials to develop the next generation of photonic devices. In this context, single wall carbon nanotubes (SWNTs) have demonstrated outstanding electrical and optical properties that make them an ideal material for the realization of ultracompact optoelectronic devices. Still, the mixture in chirality of as‐synthesized SWNTs and the necessity of precise positioning of SWNT‐based devices hinder the development of practical devices. Here, the realization of operational devices obtained using liquid solution‐based techniques is reported, which allow high‐purity sorting and localized deposition of aligned semiconducting SWNTs (s‐SWNTs). More specifically, devices are demonstrated by combining a polymer assisted extraction method, which enables a very effective selection of s‐SWNTs with a diameter of about 1–1.2 nm, with dielectrophoresis, which localizes the deposition onto silicon wafers in aligned arrays in‐between prepatterned electrodes. Thus, long semiconducting nanotubes directly contact the electrodes and, when asymmetric contacts (i.e., source and drain made of different metals) are used, each device can operate both as photoemitter and as photodetector in the telecom band around 1.55 µm in air at room temperature.     

High‐Energy Mechanical Treatment Boosts Ion Transport in Nanocrystalline Li2B4O7

In many cases fast solid ion conductors are characterized by a large number fraction of defects and vacant positions that enable the ions to move over long distances in a facile way. The introduction of structural disorder via high‐energy mechanical impact represents a very promising possibility to improve and to tune the transport properties of otherwise poorly conducting solids. Lithium tetraborate, Li₂B₄O₇, in its single crystalline form or with an average crystallite size in the μm range, is known as a very poor Li ion conductor and can serve as a model compound to study the influence of structural disorder on ion dynamics. In the present study, we used high‐energy ball milling to prepare nanocrystalline defect‐rich Li₂B₄O₇ characterized by a mean crystallite diameter of ca. 20 nm. With increasing milling time the sample became partly amorphous. Polycrystalline Li₂B₄O₇ with crystallite sizes in the order of 100 nm served as starting material. The nanostructured samples obtained show dc conductivities σ_dc in the order of 2.5 × 10^?7 S/cm at 490 K which represents an increase by more than four orders of magnitude compared to the source material. While conductivity spectroscopy was applied to study the effect of different milling times on ionic conductivity in detail; Li ion self‐diffusion in nanostructured Li₂B₄O₇ as well as in the starting material was investigated by variable‐temperature solid‐state ⁷Li nuclear magnetic resonance (NMR) relaxometry. While the first is sensitive to long‐range ion transport, lithium NMR is able to access also short‐ranged ion motions.