scholarly journals Analysis of disperse composition of the dust in air of working zone of feed mills

Author(s):  
E Agashkov ◽  
T Belova ◽  
D Terekhov ◽  
Olga Loboda
2018 ◽  
Vol 97 (3) ◽  
pp. 264-268 ◽  
Author(s):  
Nikolay A. Kashuba

Features of the aerodynamics of aerosols in the respiratory tract during respiration are considered. New methodological approaches to the evaluation of the intensity of the exposure to dust on the human respiratory organs are proposed. The difference in the dispersion composition and in the weight concentrations of the inhaled dust from the dust of the working zone air was studied. The dispersed composition and weight concentrations of cotton dust retained by separate parts of the respiratory organs were investigated. The selective ability of separate parts of respiratory organs to detain dust particles of various sizes has been detected. The regularity of the distribution of dust particles of different disperse composition and weight concentrations over separate parts of the respiratory organs is established.


2018 ◽  
Vol 6 (6) ◽  
pp. 3-11
Author(s):  
Е. Веденин ◽  
E. Vedenin ◽  
В. Дьяченко ◽  
Vladimir Dyachenko ◽  
П. Чартий ◽  
...  

Aerosol air pollution is one of the most dynamic factors of the environmenal technogenic transformation. The danger degree of the aerosol particles increases in air with their sizes reduction therefore the dust disperse composition has the great hygienic value and in the working zone air and the dust disperse composition at the enterprise border — on health of the population of these territories are the important characteristic for its It has led to the introduction of new ecological standards for mass concentration of the particles with a diameter less than 10 μ (PM10) and particles with a diameter less than 2,5 μ (PM2,5). impact assessment on health of the enterprise employees and the population of near territories. The laser methods using for the assessment of parameters of aerosol emissions and extent of their impact on the environment have been introduced in this article. The modified spectral transparency method is the best of all and suitable for determination of the average size and concentration of disperse particles. The physical model of this method is based on interaction of monochromatic laser radiation with the polydisperse aerosol by Mie’s theories and maintaining invariancy of the average factor of the extinction efficiency concerning the type of the of particles size distribution function with using of the concept of particles average volume and superficial diameter. The optical density measurement of the disperse aerosol is performed at the same time, on several wavelengths, and the average factors of the extinction efficiency for these laser radiation wavelengths can be derived from the experimental data. This method has rather simple hardware realization and allow to diagnose flows of high optical density (that is characteristic of technogenic aero disperse flows).


Author(s):  
S. P. Eron’ko ◽  
M. Yu. Tkachev ◽  
E. V. Oshovskaya ◽  
B. I. Starodubtsev ◽  
S. V. Mechik

Effective application of slag-forming mixtures (SFM), being fed into continuous castingg machine (CCM) moulds, depends on their even distribution on the melt surface. Manual feeding of the SFM which is widely usedd does not provide this condition, resulting in the necessity to actualize the work to elaborate systems of SFM mechanized feedingg into moulds of various types CCM. A concept of the designing of a system of SFM feeding into CCM moulds presented with the ratte strictly correspondent to the casting speed and providing formation of an even layer of fine material of given thickness on the whoole surface of liquid steel. The proposed methods of designing of the SFM mechanized feeding systems based on three-dimensional computer simulation with the subsequent verification of the correctness of the adopted technical solutions on field samples. Informattion is presented on the design features of the adjusted facilities intended for continuous supply of finely granulated and powder mixtuures on metal mirror in moulds at the production of high-quality billets, blooms and slabs. Variants of mechanical and pneumo-mechaanical SFM supply elaborated. At the mechanical supply the fine material from the feeding hopper is moved at a adjusted distance bby a rigid horizontally located screw. At the pneumo-mechanical supply the metered doze of the granular mixture is delivered by a sshort vertical screw, the lower part of which is located in the mixing chamber attached from below to the hopper and equipped with ann ejector serving for pneumatic supply of the SFM in a stream of transporting gas. It was proposed to use flexible spiral screws in the ffuture facilities of mechanical SFM feeding. It will enable to eliminate the restrictions stipulated by the lack of free surface for locatiion of the facility in the working zone of the tundish, as well as to decrease significantly the mass of its movable part and to decreaase the necessary power of the carriage moving mechanism driver. The novelty of the proposed technical solutions is protected by thhree patents. The reduction of 10–15% in the consumption of slag-forming mixtures during the transition from manual to mechanizeed feeding confirmed. The resulting economic effect from the implementation of technical development enables to recoup the costs inncurred within 8–10 months.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Marie Protais ◽  
Maxime Laurent-Perrot ◽  
Mickaël Artuso ◽  
M. Christian Moody ◽  
Alain Sautet ◽  
...  

Abstract Background Irreparable rotator cuff tears are common and difficult to treat. Techniques for “filling the loss of substance” require fixation to the rotator cuff stump (tendon augmentation) or to the glenoid (superior capsular reconstruction), which are complicated by the narrow working zone of the subacromial space. The main objective of this study was to determine whether a braided graft of gracilis (GR) and semitendinosus (ST) could fill a loss of tendon substance from an irreparable rupture of the supra- and infraspinatus, by fixing the graft to the greater tuberosity and the spine of the scapula. Methods This was a cadaveric study with the use of ten specimens. The GRA and ST tendons were harvested, braided and reinforced with suture. An experimental tear of the supraspinatus (SS) and upper infraspinatus (IS) retracted at the glenoid was made. The GRAST transplant was positioned over the tear. The transplant was attached to the greater tuberosity by two anchors and then attached to the medial third of the scapular spine by trans-osseous stitching. The percentage of filling obtained was then measured and passive mobility of the shoulder was assessed. We proceeded to the same technique under arthroscopy for a 73 years old patient whom we treated for a painful shoulder with irreparable cuff tear. We inserted a GRAST graft using arthroscopy. Results The Braided-GRAST allowed a 100% filling of the loss of tendon substance. Mobility was complete in all cases. Conclusion This technique simplifies the medial fixation and restores the musculo-tendinous chain where current grafting techniques only fill a tendinous defect. The transplant could have a subacromial “spacer” effect and lower the humeral head. The donor site morbidity and the fate of the transplant in-vivo are two limits to be discussed. This anatomical study paves the way for clinical experimentation.


2016 ◽  
Vol 879 ◽  
pp. 1600-1605
Author(s):  
H. Roelofs ◽  
N. Renaudot ◽  
D. Smolenicki ◽  
J. Boos ◽  
F. Kuster

Graphitized steels are claimed to perform excellent in machining processes. They therefore can be considered as environmental friendly alternatives to the widely used Pb-alloyed steels. Due to liquid metal embrittlement and in-situ lubrication Pb improves machinability in a narrow tool-chip interface temperature window corresponding to low machining speeds. Although graphite inclusions are also supposed to generate in-situ lubrication, the mechanism and the corresponding optimum working zone is not very clear. The present work applies a new test methodology (including in-situ tribology, analysis of material flow and chip formation, optimum working zone analysis) to investigate the effects of graphite inclusions on turning and drilling operations. A Pb-alloyed low carbon free-cutting steel and Pb-alloyed case hardening steel were used as reference steels.


Technologies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 96 ◽  
Author(s):  
Yury Melnik ◽  
Mikhail Kozochkin ◽  
Artur Porvatov ◽  
Anna Okunkova

The article is related to the research of the parameters of vibroacoustic emission for development of the monitoring and adaptive control system for electrical discharge machining. The classical control system based on a response of electrical parameters does not give an adequate data in the cases of a new class of materials processing as conductive ceramics reinforced by conductive nano additives and carbon nanotubes and whiskers. The idle pulses, which are working on the destruction of the erosion products in the gap, count as working pulses. The application of the monitoring and control tools based on vibroacoustic emission gives adequate data about conditions in the working zone. The developed system is available to count only impulses involved in working on the destruction of the workpiece. The experiments were conducted on the samples of materials with a low melting point as austenitic steel and aluminum alloy, and hard alloys. The records of vibroacoustic signals were analyzed for detection of the monitoring and adaptive control criteria.


Author(s):  
Dhruvesh Patel ◽  
Rohit Kalla ◽  
Halil Tetik ◽  
Gökhan Kiper ◽  
Sandipan Bandyopadhyay

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