Composition and structure of porous heat-resistant inorganic composite materials

This paper is a continuation of our series of papers devoted to the production of ceramic and composite nanomaterials based on various inorganic heat-resistant binders. The work is devoted to important aspects that determine the properties of such materials: micro- and macrostructure, and the chemical composition. These factors are of particular importance for the production of porous, heat-resistant materials. In this paper, the main types of porous heat-resistant materials are considered. Porous materials are the solids that contain voids in a sufficiently large amount, and the average size of individual voids is significantly smaller than the body size. The structure of porous materials is characterized by the following parameters: general or true porosity, closed porosity, open or apparent porosity, average pore size and size distribution function, specific pore volume, specific surface area, the degree of the material anisotropy, permeability. It is shown that the method of production of porous materials has a great influence on the formation of the pore structure of materials. By changing the technological parameters of production of porous products, it is possible to regulate both the total porosity and the nature of the structure of the porous material. The analysis and comparison of the concepts that characterize the behavior of materials at high temperatures (refractoriness, thermal resistance, heat resistance, dross resistance, high-temperature strength) have been performed. Various chemicals with the greatest thermal stability and refractoriness have been compared. Various porous heat-resistant inorganic composite materials manufactured by industry have been analyzed. Various chemicals with the greatest thermal stability and refractoriness have been shown. The phase diagrams of such compounds were analyzed. Systems and phase compositions, optimal for creating heat-resistant porous materials, were recommended

Structure of pores in solid porous bodies. Part II

Porous materials are formed from dispersed particles of various shapes. The porous structure of such materials is determined by the shape and nature of the packing of their structural units. As a model for the analysis of the structure of porous materials, model-packing units were selected in the form of spherical particles and fibers. Separately, the pore structure in foam-like regular porous materials was considered. It is shown that the pore volume in such packages grows with the reduction of the coordination number of the packed spherical particles. To study this regularity, the structural types of crystal lattices of various chemical substances were analyzed. Examples of such packages are most metallic elements and all inert gases, except for helium. These substances crystallize in simple structural types. All of them can be considered as packing of balls of identical radii. Such regularities are observed strictly up to the coordination number 4. With coordination number 3, a very openwork, loose package is formed. When forming mixed packages, the coordination number can have fractional values. A special group is represented by structures with coordination number <3

INFORMATION AND ANALYTICAL SYSTEM FOR HAZARD LEVEL ASSESSMENT AND EMERGENCY RISK FORECASTING

The purpose of the article is to present an analytical system that allows users to proces data necessary for an industrial risk analysis and management, to monitor the level of industrial safety in a given site, and to fulfil essential tasks within the field of occupational safety. This system’s implementation will make the industrial safety management at industrial sites more effective. Multifactorial, probabilistic, determined models of accidents’ hazard and severity indexes are integrated into the computing core of the Information and Analytical System. Then, statistical methods determine the risk assessment of occupational injuries and diseases. The Information and Analytical System for Hazard Level Assessment and Forecasting Risk of Emergencies in the Republic of Kazakhstan allows users to work efficiently with large volumes of information and form a united analytical electronic report about the state of industrial safety. The main objective of the monitoring system is to conduct a comprehensive analysis and assessment of the state of accidents, traumas and occupational sickness rates at industrial sites, the results being classified by the degree of hazard and insalubrity of manufacture. The introduction of the computer monitoring system in the specialized services of the Emergency Management Committee and the Ministry of Investment and Development of the Republic of Kazakhstan, and at industrial enterprises throughout the country, will allow users to analyse the state of the industrial and occupational safety constantly and objectively; as a consequence, the implementation will go a long way towards comprehensively approaching the task of increasing safety levels at industrial sites

Effect of Temperature on Physical and Mechanical Properties of Monolithic Polycarbonate

The study of the physical and mechanical properties of polycarbonate under various temperature conditions, taking into account its widespread use as a base material of monolithic polycarbonate systems in various climatic regions, will ensure a high degree of reliability of structures during operation in a wide temperature range. The authors of the article conducted a series of tensile tests of monolithic polycarbonate in the temperature range from -60 to +80 °C. The influence of temperature on the following characteristics of monolithic polycarbonate was evaluated: elongation at break, tensile yield strength, tensile stress at break, strains at the end of the elastic stage of the material. As a result of the conducted experimental studies, the relationship between the strength properties of monolithic polycarbonate and the operating temperature was revealed. The values of elongation at break at temperatures exceeding 15 °C for various samples generally correspond to the values obtained during tests conducted under standard conditions

Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−

The angular distribution and differential branching fraction of the decay B 0→ K ∗0 μ + μ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions

Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

The $B_s^0\to J/\psi K_S^0$ branching fraction is measured in a data sample corresponding to 0.41$fb^{-1}$ of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2$\beta$ measurement from $B^0\to J/\psi K_S^0$ The time-integrated branching fraction is measured to be $BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}$. This is the most precise measurement to date

Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays

A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%

Model-independent search for CP violation in D0→K−K+π−π+ and D0→π−π+π+π− decays

A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states K−K+π−π+ and π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb−1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity

Search for the lepton-flavor-violating decays Bs0→e±μ∓ and B0→e±μ∓

A search for the lepton-flavor-violating decays Bs0→e±μ∓ and B0→e±μ∓ is performed with a data sample, corresponding to an integrated luminosity of 1.0  fb-1 of pp collisions at √s=7  TeV, collected by the LHCb experiment. The observed number of Bs0→e±μ∓ and B0→e±μ∓ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0→e±μ∓)101  TeV/c2 and MLQ(B0→e±μ∓)>126  TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds

Absolute luminosity measurements with the LHCb detector at the LHC

Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic "van der Meer scan" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6, 9 and 10 and corresponding explanation in the tex