Abstract
The article considers a method for determining mathematical equations by describing experimental adsorption isotherms. These equations correspond to the main models of adsorption processes ...that are presented in this work. A method for selecting the regression coefficients of adsorption isotherms by the MathCad software is proposed. A mathematical adsorption equation for a pair of substances “ethyl alcohol - activated carbon” is found. To confirm the applicability of the obtained equation, a mathematical experiment was carried out in the Aspen Adsorption software. The result of the experiment included the values of the saturation time of the adsorbate (activated carbon) with the adsorbent (ethyl alcohol) under various conditions. An estimate of the experimental error relative to the conditions accepted in the calculation showed a satisfactory result.
The article introduces derivation of analytical equation for determining the efficiency of centrifugal counterflow mills with selective grinding. Throughput capacity of the centrifugal counterflow ...mill is one of the main factors influencing concentration of the mill material in counterflows of the discharge. Particles density in the air dynamic environment must provide collision of particles in the central zone of the discharge. If particles density is not sufficient, then particles arriving into the central zone will interact with accelerating elements of the opposing rotor. It may result in high wear of the accelerating elements and getting of the metallic dust into the prepared material. Increased material concentration in the air flow can lead to multiple interactions and buffering the particles, that will impact the grinding efficiency and result in grinding material coarsening.
This article presents the analytical expression for the determination of the degree of milling of particles in a centrifugal counter-flow mill with a selective effect on the material to be milled. ...The degree of milling is one of the most important factors characterizing the efficiency of particle collisions in the opposite intersecting flows in the tangential sleeve. The projection wx of the velocity of interaction of particles with an oblique impact is determined on the basis of the value of the tangential stresses in the zone of opposing intersecting flows. In this case, the density of counter-intersecting flows should be such that the collision of particles occurs in the zone of milling. The structural design of the mill rotors provides separation of the particle fluxes in the tangential sleeve depending on their size. This design of the rotors improves the efficiency of grinding and fineness of the finished product. A design diagram is given in order to describe the process of milling of a material in the zone of opposing intersecting flows. As a result of theoretical studies, the analytical expression was obtained that allows determining the degree of milling of material particles in the zone of tangential collisions depending on the design and technological parameters of a centrifugal counter-flow mill.
This paper describes the use of laser vibrometry and thermal non-destructive testing for detecting defects in GFRP composite by applying a single test procedure. The laser vibrometry involves the ...averaging of vibration amplitudes over an entire frequency spectrum accompanied by the frequency-phase analysis. Such procedure may lead to suppression of low signals, produced by smaller and deeper defects, by higher signals conditioned by larger and shallower defects. The fusion of results obtained with both laser vibrometry and thermal NDT was used to enhance defect detectability. The corresponding experimental techniques were applied to detecting four types of defects (air gaps, foam, blank grooves, resin) in GFRP composite, as well as evaluating defect size and depth. Also, laser vibrometry was used to characterise barely visible impact damage in CFRP composite, and test data was compared with C-scan ultrasonic inspection results. It has been shown that the results supplied by three inspection techniques have been reasonably consistent in characterisation of defect lateral area and depth. When analysing the complex structure of impact damage in composites, the detection of both shallow and deep defects can also be enhanced by performing fusion of test results supplied by laser vibrometry and active thermal NDT.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This article describes the analytical method of measuring the secondary power consumption, necessitated by the installation of a grading device in the peripheral part of the grinding chamber in the ...desintegrator. There is a calculation model for defining the power input of the disintegrator increased by the extra power demand, required to rotate the grading device and to grind the material in the area between the external row of hammers and the grading device. The work has determined the inertia moments of a cylindrical section of the grading device with armour plates. The processing capacity of the grading device is adjusted to the conveying capacity of the auger feeder. The grading device enables one to increase the concentration of particles in the peripheral part of the grinding chamber and the amount of interaction between particles and armour plates as well as the number of colliding particles. The perforated sections provide the output of the ground material with the proper size granules, which together with the effects of armour plates, improves the efficiency of grinding. The power demand to rotate the grading device does not exceed the admissible value.
This article discusses a study of transformer–rectifier units with a magnetic core made of amorphous steel. Transformers with various types of amorphous alloys have been analyzed, and the optimum ...amorphous alloy for transformers was determined. Thermal processes in transformers with magnetic core of amorphous steel have been simulated, and the maximum temperature under normal operating conditions has been determined. The simulation has demonstrated that no special transformer cooling system is required. An experimental transformer–rectifier unit has been designed and manufactured with a magnetic core of amorphous steel installed on an 18-pulse rectifier with a capacity of 10.5 kV A operating with a frequency of 400–800 Hz and voltage of 115/27 V. To verify the obtained data, experimental studies have been performed that confirmed the validity of the selected design procedure of a transformer engineering flowchart. It has been demonstrated that the thermal loads detected in the transformer during testing are in the range of allowable values.
Scientific investigations conducted at VIR during 1960-2014 to identify sources of new promising and economically useful traits in rye resulted in the development of genetic donors of such traits ...capable of increasing breeders’ work efficiency. These results helped to initiate the development of new priority trends in winter rye breeding, such as breeding of heterosis hybrid cultivars, semi-dwarf non-lodging cultivars, cultivars resistant to fungal diseases, semi-dwarf forms with higher productivity on the basis of plant photosynthesis potential optimization, and rye cultivars with low pentosan content for universal utilization.
Lower extremity deformities of patients with arthrogryposis multiplex congenita present a wide spectrum of severity and deformity combinations. Treatment goals range from merely ensuring comfortable ...seating and shoe wear, to fully independent and active ambulation, but the overarching intention is to help realize the patient’s greatest potential for independence and function. Treatment of hip and knee contractures and dislocations has become more interventional, whereas treatment of foot deformities has paradoxically become much less surgical. This article synopsizes the treatment strategies presented in September 2014 in Saint Petersburg, Russia at the second international symposium on arthrogryposis.
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