Refractory ceramic sets for nonferrous metallurgy and experience of their operation

Refractory ceramic materials have been developed in FGUP ONPP Tekhnologiya, and technology has been created for preparing ceramic objects for use in nonferrous metallurgy. Crucibles, burner hoods, and other forms of objects are manufactured from material based on aluminum oxide, required for pouring metals and alloys. A broad range of objects for aluminum casting installations are manufactured from materials based on wollastonite. Information is presented about the ceramic objects produced and experience of their operation in nonferrous metallurgy enterprises.     

Photomicrographic size distribution determination of non-spherical objects

Equations have been developed for calculating the size distribution of non-spherical objects by using photomicrographs prepared of sections or projections of samples. The equations contain the shape function characteristic of the shape of the objects in the sample which is also determined from the photomicrographs. The equations have been applied to the void size distribution determination in various sandstones and packed beds of beads, as well as to the particle size distribution determination of a sample of common salt. It has been found that the new equations resulted in plausible calculated size distributions in the case of highly anisotropic objects, whereas this was not the case when the sphere model was used as a basis for the calculations. In the case of the salt particles, however, the sphere model was almost equally adequate as the shape function method, because the shape function was, in this case, very nearly spherical.     

FREE OBJECT MOTION IN A GAS FLUIDIZED BED

The presence probability, the characteristic motions and the velocity of various “light” objects freely immersed in a gas fluidized bed of “heavy” fine particles have been investigated as a function of superficial fluid velocity, powder characteristics and bed height. The displacement of objects through the bed has been shown to result from both a “deterministic” dynamic force equilibrium and a “stochastic” stirring effect due to bubbles. A specific gas velocity exists at which a deep change in mixing occurs: above it the stirring effect is fairly noticeable, while below it pseudo-hydrostatic effects prevail. A method has been proposed to estimate this characteristic value.     

Investigation of sol-gel derived nanomaterials with a hierarchical structure

The basic processes of self-assembly in sol-gel technologies during the formation of network nanomaterials with a hierarchical structure have been considered. The gas-sensitive fractal structures have been prepared in systems based on dioxides of tin and silicon. The formation of a structure of nanocomposites has been studied using atomic force microscopy and electron microscopy methods. The gas-sensitive properties of nanomaterials have been investigated. A method for diagnosing objects with a hierarchical structure based on metal oxides has been proposed.     

Evaluation of the structural parameters of two-phase glasses from transmission electron microscope images

Electron microscope images of the sodium borosilicate glass with a two-network structure have been analyzed. The relative volume of the phases in the glass has been calculated using the computer program written in the MatLab language for analyzing and processing images, in which the histogram of the analyzed gray-scale image has been used. The results obtained have been compared with the structural parameters of the glass according to the data of reference methods. An approach has been proposed to the formulation of rules for evaluating the characteristics of the objects under investigation from the regions chosen in the image to be analyzed.     

Contemporary technology for preparing high density periclase powder

A unit has been put into operation in OAO Kombinat Magnezit for producing densely sintered periclase. A production scheme is described. Advantages are demonstrated for using high-density periclase powder for preparing refractory objects compared with powders sintered in a rotary furnace.     

金属文物的清洗

介绍金属文物清洗操作的一般过程,阐述适宜金属文物清洗的对象,清洗方案的制定和调整,清洗的程序和方法,使用的设备、材料和配方,清洗后的档案记录。     

Experimental investigation and material modelling of fresh and UV aged Japanese lacquer (Urushi)

Urushi is a complex natural polymer that has been used to protect and decorate objects for many hundreds of years. It is an important material as decorated objects can obtain great value and historical worth. These objects are often exposed to environments that are detrimental to both their aesthetic appeal and structural performance and restoration and conservation procedures are needed to preserve these objects over long periods of time. The conservation work requires a detailed understanding of the material properties of the Urushi lacquer film. However, Urushi exhibits complex viscoelastic behaviour under load that has not been fully characterised to date. This paper presents the sample preparation technique and experimental data from a comprehensive mechanical testing programme for Urushi film. The viscoelastic response was investigated by tests at various loading speeds and creep and recovery tests. A number of constitutive models were fitted to the creep and recovery data and a good fit was seen with a number of these, most notably a modified generalized Kelvin fluid (MGKF) model. Some samples of Urushi were artificially aged by laboratory exposure to ultraviolet (UV) irradiation before mechanical testing. The ageing increased strength and reduced the ductility of the Urushi and it was shown that the MGKF model was capable of modelling the ageing behaviour by using ageing-time dependent material parameters. The models were implemented in the commercial FEA software ABAQUS, offering the potential to accurately model the Urushi behaviour in a complex structure.     

Optimization of technological processes from a limited set of experimental data

Conclusions A set of algorithms and programs has been developed; the basis of these is the idea of heuristic self-organization and statistical search; it permits one to prepare models of complex chemical engineering objects from a limited set of experimental data and to use these models to optimize the functioning regimes of these objects.Testing of the mathematical apparatus developed in the case of optimizing the process of spinning a polymer solution shows the advisability of using it in the stages of experimental and pilot-plant operation of chemical engineering objects.Translated from Khimicheskie Volokna, No. 5, pp. 11–13, September–October, 1989.     

Familiar objects and memory color

Memory color for a set of eight different familiar objects has been investigated. Our results obtained with one hundred observers, eighty color samples of NCS, and two illuminants indicate that: (a) the shifts that are produced in the dominant wavelength with memory depend on the familiar object considered; (b) colorimetric purity, as a measure of saturation, of the remembered objects is not the same as that of the familiar objects; (c) in the SVF representation space, with illuminant D65 and regardless of experience in color matching of the observer, the color that was best remembered was purple aubergine and the worst remembered was brown chestnut. With the illuminant A, red tomato was the best remembered color and yellow lemon the worst. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23: 416–427, 1998     

AGGREGATION AND BREAKAGE OF SOLID PARTICLES IN SUSPENSIONS AGITATED IN A VIBRATING MIXER: A FRACTAL APPROACH

A lumped discrete population balance model has been selected for the verification of the experimental data. Solid aggregates of chalk suspended in vigorously mixed suspension were treated as fractal objects with a mass fractal dimension taken as 2.02. A specially written computer program has been used for determining the evolution of population of aggregates during the course of mixing. The PSD (particle size distribution) results obtained by numerical calculation for fractal and non-fractal approaches have been compared, showing a better fit in the case of the fractal model. The aggregation and breakage rate coefficients were correlated as a function of the average energy dissipation rate in the vibrating mixer.     

On the critical stokes' number for particle transport in potential and viscous flows near bluff bodies

The inertial deposition of flowing aerosols past a variety of symmetrically shaped objects is investigated. The existence of a critical value of the Stokes' number, below which no particles may be deposited on the object in finite time, has been suggested and a plausible reason for this, using linearized theory, has been given. In this paper a more rigorous non-linear mathematical argument is developed and shows that for potential flow a non-zero value of the critical Stokes' number is obtained, whilst for viscous flow the critical Stokes' number is zero.     

AGGREGATION AND BREAKAGE OF SOLID PARTICLES IN SUSPENSIONS AGITATED IN A VIBRATING MIXER: A FRACTAL APPROACH

A lumped discrete population balance model has been selected for the verification of the experimental data. Solid aggregates of chalk suspended in vigorously mixed suspension were treated as fractal objects with a mass fractal dimension taken as 2.02. A specially written computer program has been used for determining the evolution of population of aggregates during the course of mixing. The PSD (particle size distribution) results obtained by numerical calculation for fractal and non-fractal approaches have been compared, showing a better fit in the case of the fractal model. The aggregation and breakage rate coefficients were correlated as a function of the average energy dissipation rate in the vibrating mixer.     

Colour appearance rating of familiar real objects

The determination of the long‐term memory colours of objects has been the subject of investigation for many years. Colour acceptance boundaries have been determined from the visual assessments of objects under variable illumination or by presenting manipulated images of objects on a calibrated computer display. However, a systematic and quantitative rating of the colour of real objects with respect to memory colour is not available at this moment. In this article, nine familiar real objects with colours distributed around the hue circle were positioned in a specially designed LED illumination box. For each object, approximately hundred real illumination spectra were synthesized in a random order keeping the luminance of the object approximately constant. Observers were asked to rate, on a five‐point scale, the similarity of the perceived object colour to their idea of what the object looked like in reality. By avoiding specular reflections, the observer was unable to identify any clues as to the colour of the illumination. For each object, similarity ratings showed a good intraobserver and interobserver agreement. The ratings of all the observers were pooled and successfully modeled in IPT colour space by a bivariate Gaussian distribution. It was found that the chromaticity corresponding to the highest rating tended to be shifted toward higher chroma in comparison with the chromaticity calculated under D65 illumination. The bivariate distributions could be very useful in applications where the quantitative evaluation of the colour appearance of an object stimulus is required, such as in the evaluation of the colour rendering capabilities of a light source. © 2010 Wiley Periodicals, Inc. Col Res Appl, 36, 192–200, 2011;     

Selective Laser Melting of Soda‐Lime Glass Powder

Although process parameters of Selective Laser Melting (SLM) method have been established for different materials, fabrication of parts using SLM of glass powder has remained a challenge so far. This study presents a synopsis of an experimental investigation study on SLM of soda‐lime glass powder. The process parameters are analyzed using various test geometries, and a set of optimized process parameters is determined and used to build multiple objects. The morphology and mechanical properties of the fabricated parts are analyzed. The results demonstrate the feasibility of SLM process to successfully build objects from soda‐lime glass powder for different applications.     

Physical indices for judging appearance harmony of materials

In visual design, harmony refers to the similarity among objects and the components of these objects that appear as if they belong together. Harmony is related to the body, mind, and emotions as we relate to our living space, which means that the harmony of real objects is an important characteristic. Although the appearance harmony in specific materials has been investigated, harmony among different materials has not received adequate attention. In a previous study, we investigated the appearance harmony among various materials by psychophysical experiments. In this study, we correlated the psychophysical evaluations obtained from the experiments and the physical properties of the materials. By analyzing the relationship between psychophysical evaluations and the physical measurements for each material pairs based on cluster analysis, we found that the property of texture represented by the anisotropy histogram and that of reflectance obtained from the data of the bidirectional reflectance distribution function are important indices that can be used to judge the harmony of materials. In particular, the texture properties were more effective in judging the appearance harmony of material pairs in the fixed condition for illumination and viewing angles, and the reflectance properties were superior for the material pairs in the variable condition for illumination and viewing angles.     

深浅聚散万取一收-陶艺的模糊性散论

在茫茫的宇宙中,模糊现象无处不在,形状千差万别,性质多种多样,既有确定的明晰的一面,又有不确定的模糊的一面。客观事物既有被认知的,也有未被认知的,客观世界中也存在着确定与不确定,明晰与模糊的运动变化,势必影响到文学艺术作品的发展变化,也必然或多或少地反应在我们的作品中;也会时隐时现的反映在我们的作品之中,成为作品中充满生机的一部分。陶瓷艺术是客观世界的再现与表现,是陶艺家主观情感的升华。陶艺作为一门艺术形式,也必然存在着明晰与模糊的双重性,陶艺的模糊性也必然反映在作品中,体现在构思到表现手法与工艺制作的方方面面。     

Challenges for nanomechanical sensors in biological detection

Nanomechanical biosensing relies on changes in the movement and deformation of micro- and nanoscale objects when they interact with biomolecules and other biological targets. This field of research has provided ever-increasing records in the sensitivity of label-free detection but it has not yet been established as a practical alternative for biological detection. We analyze here the latest advancements in the field, along with the challenges remaining for nanomechanical biosensors to become a commonly used tool in biology and biochemistry laboratories.     

Air Drying of Food and Biological Materials—Modified Biot and Lewis Number Analysis

Abstract

In this paper, a modified Biot and Lewis number analysis of air-drying of food and biological objects with small sizes has been carried out. It has been shown that the evaporative action broadens the range of the application of the conventional Biot assessment for uniform temperature approach. For evaluating whether heat or mass transfer is the limiting process for drying, the article has preliminarily demonstrated that the inclusion of the sorption characteristics of the material being dried in the calculation of the effective diffusivity for water vapor predicts larger Lewis numbers (greater than unity). Sample calculations are given in this article based on previous laboratory results.     

Perception of gold materials by projecting a solid color on black materials

Gold gives a unique luxurious impression and therefore golden objects are often desired. Since gold is an expensive metal, due to its rarity, it is not feasible to produce objects made of gold at reasonable prices. In this study, we have developed a simple representation method that makes real objects appear to be made of gold using projection mapping technology. In recent years, this technology has been extensively explored, mainly in the field of entertainment. Most of these studies were focused on technologies where a target image was superimposed onto an object. Our method, unlike the conventional approach, does not project a target gold image but simply projects a solid color onto an object, thereby giving the perception that the object is made of gold. We have conducted two psychophysical experiments to substantiate our representation method, using stimuli having the same color. Our results indicate that objects were more easily perceived as golden objects when a solid color was projected onto black objects rather than white objects. Furthermore, a few samples were perceived as metals, even though they were actually paper or fabric. These results suggest that when superimposing a solid color onto an object, a change in material type is perceived along with the change of its color. Moreover, we analyzed the relationship between psychophysical evaluations on the perception of projected gold objects and the physical properties of the materials. The results show that the average and the standard deviation of reflectance generated by black objects can be considered factors that affect the perception of a gold‐like color. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 522–530, 2017