In situ контроль шероховатости при финишной обработке неметаллических материалов

Описано схему обладнання для моніторингу поверхні в процесі полірування, що здійснюється за допомогою оптичних методів. Відношення інтенсивності променю, що відбивається від поверхні, до інтенсивності падаючого променю дозволяє оцінити коефіцієнт відбивання in situ. Встановлено, що в процесі зменшення шорсткості поверхні її коефіцієнт відбивання збільшується.The optical monitoring system for finishing processing surfaces is described. The relation of intensity of the beam reflected from a surface, to intensity of a falling beam allows to estimate a reflexion index in situ. Increase of reflexion index in process of roughness decrease is established.Описана схема установки для мониторинга поверхности в процессе полирования, осуществляемого при помощи оптических методов. Отношение интенсивности луча, отраженного от поверхности, к интенсивности падающего луча позволяет оценивать коэффициент отражения света in situ. Установлено, что в процессе уменьшения шероховатости поверхности ее коэффициент отражения увеличивается

Bound-abrasive grinding and polishing of surfaces of optical materials

International audienceProblems of efficiency and quality improvement of diamond abrasive finishing of optical materials by tools with bounded polishing powders, including diamond powder, are considered. The dependences of the particle number on the diffusion angle and coordinate of the contact have been derived in the studies of the dynamics of collision and diffusion of slime particles. The coordinate dependence of the flat surface roughnessof glass K8 optics in fine diamond grinding has been described. Interaction and dispersion of deterioration particles in a contact zone ofthe tool and the processed sample in the course of polishing is described and the dispersion structure of deterioration particles of the tool on slimeparticles and on deterioration particles is explained oscillatory. It is shown a that differential dispersion section of deterioration particles on slimeparticles is not less than on deterioration particles and is maximum at corners of dispersion close to 0◦ and 180◦ on the central sites of a contactzone. Coordinate dependence of the full dispersion section of deterioration particles of the tool and dependence of microprofile height of theprocessed surface on circular zones radius are calculated

Causes Of Low Efficiency Of Combined Ventilation System In Coal Mines In Resolving The Problem Of Air Leaks (Inflows) Between Levels And Surface

The paper discusses the problem of the underground mining safety control. The long-term air intake to coal accumulations is reviewed as one of the reasons of endogenous fires during mining. The methods of combating air leaks (inflows) in order to prevent endogenous fires are analyzed. The calculations showing the discrepancy between the design calculations for the mine ventilation, disregarding a number of mining-andgeological and mining-engineering factors, and the actual conditions of mining are given. It is proved that the conversion of operating mines to combined (pressure and exhaust) ventilation system in order to reduce the endogenous fire hazard of underground mining is unreasonable due to impossibility of providing an optimal distribution of aerodynamic pressure in mines. The conversion does not exclude the entry of air into potentially hazardous zones of endogenous fires. The essence of the combined application of positive and negative control methods for the distribution of air pressure is revealed. It consists of air doors installation in easily ventilated airways and installation of pressure equalization chambers equipped with auxiliary fans near the stoppings, working sections and in parallel airways.The effectiveness of the combined application of negative and positive control methods for the air pressure distribution in order to reduce endogenous fire hazard of mining operations is proved

Causes Of Low Efficiency Of Combined Ventilation System In Coal Mines In Resolving The Problem Of Air Leaks (Inflows) Between Levels And Surface

The paper discusses the problem of the underground mining safety control. The long-term air intake to coal accumulations is reviewed as one of the reasons of endogenous fires during mining. The methods of combating air leaks (inflows) in order to prevent endogenous fires are analyzed. The calculations showing the discrepancy between the design calculations for the mine ventilation, disregarding a number of mining-andgeological and mining-engineering factors, and the actual conditions of mining are given. It is proved that the conversion of operating mines to combined (pressure and exhaust) ventilation system in order to reduce the endogenous fire hazard of underground mining is unreasonable due to impossibility of providing an optimal distribution of aerodynamic pressure in mines. The conversion does not exclude the entry of air into potentially hazardous zones of endogenous fires. The essence of the combined application of positive and negative control methods for the distribution of air pressure is revealed. It consists of air doors installation in easily ventilated airways and installation of pressure equalization chambers equipped with auxiliary fans near the stoppings, working sections and in parallel airways.The effectiveness of the combined application of negative and positive control methods for the air pressure distribution in order to reduce endogenous fire hazard of mining operations is proved

In situ control of roughness of surfaces at polishing by reflectometric metod

International audienceIt is demonstrated that the removal rate in polishing optic materials decreases exponentially with increasing bond energy in these materials and the polished surface roughness depends on the ratio of natural frequencies of molecular fragments on the tool and workpiece surfaces. The dependences of polished surface roughness on the slime particle size, permit an optimal choice of powders for a bound-abrasive polishing tools, which will ensure a required polished surface quality. The dependences of the polished surface microprofile parameters on the coordinate of a zone under study, which were described by periodic functions, do represent the effects that occur in the tool-workpiece contact zone. The optical monitoring system, the device for giving of the technological environment in a zone of contact of the tool and a processed detail and a technique of adjustment of the machine tool for finishing processing of precision optic surfaces are described. The relation of intensity of the beam reflected from a surface, to intensity of a falling beam allows to estimate a reflexion index in situ. Increase of reflexion index in process of roughness decrease is established. Possibility of active quality assurance of precision surfaces in the course of processing is shown

Problem Of Methane-Air Mixture Explosions In Working Faces Of Coal Mines At Mining Intensification And Ways Of Its Solution

The paper presents the problem of methane explosions prevention in the most hazardous mine section — working face, based on the preventive measures to exclude key factors of methane explosion. The measures of the methane explosions prevention in the working faces during the intensification of coal mining are determined. A method for the aggregated calculation of absolute methane emission in the working face at work of a shearer is proposed. An explosive concentration can occur at any time during cutting coal due to irregularity of methane emission and ventilation processes in the face, which makes the risk of explosion uncontrollable. Consequently, the effective preventive drainage of coal seams is primarily required for the intensification of coal mining. A series of new studies on intensity of methane emission will be required for per face output which is about 30,000 tons per day or more to create new regulatory documents

Problem Of Methane-Air Mixture Explosions In Working Faces Of Coal Mines At Mining Intensification And Ways Of Its Solution

The paper presents the problem of methane explosions prevention in the most hazardous mine section — working face, based on the preventive measures to exclude key factors of methane explosion. The measures of the methane explosions prevention in the working faces during the intensification of coal mining are determined. A method for the aggregated calculation of absolute methane emission in the working face at work of a shearer is proposed. An explosive concentration can occur at any time during cutting coal due to irregularity of methane emission and ventilation processes in the face, which makes the risk of explosion uncontrollable. Consequently, the effective preventive drainage of coal seams is primarily required for the intensification of coal mining. A series of new studies on intensity of methane emission will be required for per face output which is about 30,000 tons per day or more to create new regulatory documents

Stress reaction to cooling: entropic and chaotic estimation

The local limb cooling provides the special psychophysiology reaction as alteration of tremor parameters. Shannon’s entropy after limb cooling is researched. The efficacy of such approaches for quantity estimation according to Eskov-Zinchenko effect at biomechanics is presented. Entropy E value and quasi-attractor parameters for one person with multi repetition of tremor registration (N=225 repetition) is shown. All these 15 samples with 15 series (registration of tremorogramm of one person) present the stable value of E and quasi-attractor sequence for 225 repetitions. When the Lorenz attractors demonstrate mixing property the invariant means correspond the determined chaos. But the stress perturbation (5 min. cooling of limb in water t = 5 ºС) does not change the E value. Three groups of subjects do not present the distinction between groups without stress and after cooling of limb. So it is necessary to construct the new theory for cooling stress (not stochastic approach) in psychophysiology. The new approaches is realized according to the new theory of self-organization chaos. As a result, E entropy parameters are not obtained while the quasi-attractor (S) parameter for termograms differ significantly. This proves the uniqueness of self-organization chaos theory, and opens up new opportunities to use this new theory in psychology and psychophysiology. Objective evaluation of stress – the human response to external agents – is a very difficult task for the quantitative description and simulation. As part of chaos theory self-organizing it now becomes possible. In this case, Eskov-Zinchenko effect will be recorded only regarding quasi-attractors and matrix of pairwise comparison of samples with the calculation of k matches

The effect of N.A. Bernstein in the evaluation of tremor parameters for different acoustic effects

The reaction of the regulatory systems of the neuromuscular system of the human to the various acoustic effects (white noise, rhythmic music, classical music, hard rock) using special methods (e.g. chaos theory, self-organization) and methods of conventional statistics was studied. The state of hearing with or without acoustic impact is studied. However, the approach used is based on the analysis of the quasi-attractors parameters of the neuromuscular system (postural tremor) with simultaneous registration of left and right hand tremorogramm (in terms of sound effects). Acoustic effects played a role of a disturbing factor for tremor regulation (and muscle activity); it changes the psychophysiological state of the subject (N.A. Bernstein C and D regulation system). The designed matrix method of analysis enables the identification of systems with chaotic organization that was shown in this work by comparing left and right hand tremorogramm of subjects at different acoustic effects. The acoustic effects are regarded as disturbing influences affecting the mental state of homeostasis. In this case the main task is a quantitative assessment of mental status test calculations by tremorogramm parameters. Quasi-attractor parameters calculation method demonstrates the differences in tremorogramm of left and right hands and tremor responses to acoustic feedback. This employs a new approach in the evaluation of motor asymmetry and the method of recording the parameters of mental homeostasis by tremorogramm of chaotic dynamics. The problem of registering human mental status in cognitive psychology is resolved with a high degree of uncertainty (Bernstein). The acoustic effects are considered as disturbance affecting the mental state of homeostasis. In this case the main task is to hold a quantitative assessment of the mental state by means of calculating tremorogramm parameters. A method for calculating quasi-attractor parameters, which shows differences in left and right hand tremorogramms and tremor responses to acoustic feedback. In fact, a new approach in evaluating motor asymmetry and the method of recording the parameters of mental homeostasis by chaotic dynamics tremorogramm are proposed

Bioinert Properties of a Coronary Stent with Nanostructural Carbon Coating

ABSTRACT The article is dedicated to study of bioinert properties of a coronary stent with nanostructural carbon coating by the up-to-date methods of intravascular visualization. It was evidenced that use of a stent with nanostructural carbon coating results in reduction of the risk of in-stent stenosis by more then 2 times as compared to endoprostheses made of stainless steel without surface modification and does not induce thrombogenesis when standard antiaggregant doses are used