EXPERIMENTAL STUDIES OF PNEUMATIC IMPACT DEVICE WITH A REDUCED SPECIFIC CONSUMPTION OF COMPRESSED AIR

2020 ◽  
Vol 7 (2) ◽  
pp. 47-52
Author(s):  
P. N. Tambovtsev
Keyword(s):  
Experimental Studies ◽  
Specific Consumption ◽  
Compressed Air ◽  
Impact Device ◽  
Pneumatic Impact

A Study on Machining and Environmental Characteristics of Micro-Drilling Process Using Nanofluid Minimum Quantity Lubrication

2011 ◽  
Author(s):  
Jung Soo Nam ◽  
Pil-Ho Lee ◽  
Sang Won Lee
Keyword(s):  
Experimental Studies ◽  
Minimum Quantity Lubrication ◽  
Compressed Air ◽  
Drilling Process ◽  
Environmental Characteristics ◽  
Minimum Quantity ◽  
System A ◽  
Micro Drilling ◽  
Nanofluid Minimum Quantity Lubrication ◽  
Oil Mist

This paper presents two basic experimental studies of a micro-drilling process with nanofluid minimum quantity lubrication (MQL) in terms of machining and environmental characteristics. By using a miniaturized desktop machine tool system, a series of micro drilling experiments were conducted in the cases of dry, compressed air and nanofluid MQL. The experimental results imply that nanofluid MQL significantly reduces the adhesion of chips when compared with the cases of dry and compressed air micro-drilling. As a result, it is observed that the magnitudes of average drilling torque and thrust force are decreased and the tool life of micro drills is extended in the case of nanofluid MQL micro-drilling process. In addition, the empirical study on environmental characteristics of MQL micro-drilling process is conducted by measuring MQL oil mist with the oil sampling method. The results show that remaining MQL oil mist is tiny enough not to have a detrimental effect on human health.

scholarly journals ТЕХНОЛОГІЧНІ АСПЕКТИ ЗАБЕЗПЕЧЕННЯ ЯКОСТІ ДЕТАЛЕЙ ПРИ ПНЕВМОУДАРНОМУ ШТАМПУВАННІ ВИРУБУВАННЯМ-ПРОБИВАННЯМ

2020 ◽  
pp. 137-150
Author(s):  
В. В. Кухар ◽  
Є. А. Фролов ◽  
С. Г. Ясько
Keyword(s):  
Elastic Medium ◽  
Sheet Material ◽  
Experimental Studies ◽  
High Strength ◽  
Technological Capabilities ◽  
Sheet Metal Parts ◽  
Pneumatic Impact ◽  
Cutting Surface ◽  
Similar Character ◽  
Cutting Processes

The paper considers the issues related with technological capabilities and features of the process of cutting-punching of sheet-metal parts with an elastic medium of pneumatic impact stamping, taking into account the indicators of their quality and accuracy, and also suggests effective ways to improve them. One of the promising methods for producing high-precision parts, including those with a complex profile, is a shaping method based on the technology and equipment of pneumatic shock stamping with an elastic medium on the TA-1324 in-stallations. The advantages of this method are environmental cleanliness, safe operation, wide technological capabilities, mobility and versatility, low labour and energy costs. At these installations it is advisable to perform formative operations of separation (cutting-punching) and shallow shaping both as a separate operation and together with cutting-punching. As a workpiece for the study the sheet material of the following grades was used: steel 08kp, aluminium alloy AMG-M, steel 12X18H10T. The thickness varied within the range from 0.5 to 2.5 mm. Dies and copier punches were made of U8A steel, followed by heat treatment to a hardness of HRC 56-62. An analysis of the experimental studies of punching-cutting processes allows us to conclude that with an increase in the number of stamped parts, there is an increase in size deviations from their nominal values. This increase is due to the wear of operating elements (copier punches and dies). At the same time, the sizes of the copier punches are reduced, and the sizes of the matrices are increased. The absolute values of deviations do not depend on the type of operations; their values, both during cutting and punching, are almost the same in each of the samples taken. The process of pneumatic impact stamping, where a hammer with a bevelled end was used, has a similar character. The paper also proposed and tested ways to improve pneumatic impact stamping, providing cutting, punching of parts from sheet copper, aluminium alloys with a thickness of 0.3 to 3 mm and mild steel up to 3 mm thick. The roughness of the cutting surface is in the range Ra = 0.3 to 0.6 μm, and in the case of high-strength materials up to 2.5 mm thick, the roughness of the cutting surface is Ra = 0.6 to 1.0 μm, depending on the contour configuration that is cut down or punched.

scholarly journals Development of a Rat Model of Graded Contusive Spinal Cord Injury Using a Pneumatic Impact Device

2004 ◽  
Vol 19 (4) ◽  
pp. 574 ◽  
Author(s):  
Sang Jun Yeo ◽  
Sung Nam Hwang ◽  
Seung Won Park ◽  
Young Baeg Kim ◽  
Byung Kook Min ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Rat Model ◽  
Impact Device ◽  
Pneumatic Impact ◽  
Cord Injury ◽  
Contusive Spinal Cord Injury

Acclimatization to diving: a systematic review

2021 ◽  
Vol 03 (01) ◽  
pp. 127-147
Author(s):  
Jan Risberg ◽  
◽  
Keyword(s):  
Systematic Review ◽  
Decompression Sickness ◽  
Experimental Studies ◽  
Subjective Health ◽  
Epidemiological Studies ◽  
Compressed Air ◽  
Cochrane Library ◽  
Hyperbaric Exposure ◽  
Review Reports ◽  
Sensitizing Effect

Multiday hyperbaric exposure has been shown to reduce the incidence of decompression sickness (DCS) of compressed-air workers. This effect, termed acclimatization, has been addressed in a number of studies, but no comprehensive review has been published. This systematic review reports the findings of a literature search. PubMed, Ovid Embase, The Cochrane Library and Rubicon Research Repository were searched for studies reporting DCS incidence, venous gas embolism (VGE) or subjective health reports after multiday hyperbaric exposure in man and experimental animals. Twenty-nine studies fulfilled inclusion criteria. Three epidemiological studies reported statistically significant acclimatization to DCS in compressed- air workers after multiday hyperbaric exposure. One experimental study observed less itching after standardized simulated dives. Two human experimental studies reported lower DCS incidence after multiday immersed diving. Acclimatization to DCS has been observed in six animal species. Multiday diving had less consistent effect on VGE after hyperbaric exposure in man. Four studies observed acclimatization while no statistically significant acclimatization was reported in the remaining eight studies. A questionnaire study did not report any change in self-perceived health after multiday diving. This systematic review has not identified any study suggesting a sensitizing effect of multiday diving, and there is a lack of data supporting benefit of a day off diving after a certain number of consecutive diving days. The results suggest that multiday hyperbaric exposure probably will have an acclimatizing effect and protects from DCS. The mechanisms causing acclimatization, extent of protection and optimal procedure for acclimatization has been insufficiently investigated.

scholarly journals Introductory remarks to the fourth session

1984 ◽  
Vol 304 (1118) ◽  
pp. 151-152
Keyword(s):  
Great Britain ◽  
United States Of America ◽  
Experimental Studies ◽  
Signs And Symptoms ◽  
The United States ◽  
The Body ◽  
Compressed Air ◽  
Dissolved Gas ◽  
Considerable Body ◽  
Fourth Session

The subjects of this session range from physics through neurophysiology to epidemiology but can, without using too high a level of abstraction, be related by the underlying presumption that the separation of dissolved gas from solution upon decompression leads to the formation of bubbles in the body and that they, in turn, produce pathological effects. An increasingly large workforce was exposed to raised pressures during the second half of the nineteenth century particularly in building the foundations of a bridge by the method of Triger (1841), a method that used compressed air to exclude water from the workings. The disturbances caused by the application of pressure and, more seriously, following the reduction in pressure were described by many authors from France, Italy, Germany, Great Britain and the United States of America. So there was a considerable body of observational data and hypothesis available by 1900 and the first experimental studies of decompression had been done by Bert (1878). He established that gas was indeed produced on decompression; that, after exposure to compressed air, the main constituent of bubbles was nitrogen and he thought it probable that such bubbles caused the signs and symptoms previously recognized as being associated with decompression.

scholarly journals Study of the Process of Lubricant Application on the Friction Surface Using Aerosol Lubricators

2018 ◽  
Vol 7 (4.3) ◽  
pp. 20 ◽  
Author(s):  
Serhii Voronin ◽  
Ivan Hrunyk ◽  
Bashir Asadov ◽  
Dmytro Onopreychuk ◽  
Volodymyr Stefanov
Keyword(s):  
Friction Surface ◽  
Structural Model ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Compressed Air ◽  
Rolling Stock ◽  
Lubricant Layer ◽  
Air Supply ◽  
Lubricant Application ◽  
Friction Surfaces

The problem of calculation and forecasting main parameters of aerosol lubricators designed for applying lubricants on angled to the horizon friction surfaces e.g. the lateral surfaces of a rail and a wheel flange of railway rolling stock is solved in the article.  The main parameters of lubricators being considered in the article are compressed air supply, the geometry of a spray nozzle and the boundary thickness of a lubricant layer applied to the friction surface where there is no creep of a lubricant under the action of gravity. A structural model of application and retention of a lubricant on a friction surface has been proposed. A mathematical model to calculate main parameters of aerosol lubricators has been developed. The model establishes the connection between the geometry of lubricated friction surfaces, physico-chemical properties of lubricants and the diameter of nozzle aperture and the compressed air supply. The example of calculation of the boundary thickness of a lubricant layer applied to the friction surface under the condition of the absence of its creeping under the action of gravity has been presented in the article. The article presents the results of experimental studies the process of aerosol application of a lubricant to the friction surface. 

scholarly journals Magnetic-centrifugal drying of compressed air of pneumatic systems of machine-building enterprises

2021 ◽  
Vol 2131 (2) ◽  
pp. 022033
Author(s):  
A Totay ◽  
S Galyuzhin ◽  
A Galyuzhin
Keyword(s):  
Magnetic Field ◽  
Centrifugal Force ◽  
High Efficiency ◽  
Experimental Studies ◽  
Machine Building ◽  
Compressed Air ◽  
Force Action ◽  
Water Particle ◽  
Advantages And Disadvantages ◽  
Building Enterprises

Abstract The article analyzes such basic methods of drying compressed air of pneumatic systems of machine-building enterprises as condensation, sorption, diffusion and force action and determines the advantages and disadvantages of each of these methods. It is noted that the method of force action on water particles due to the use of the centrifugal force allows you to remove only droplet moisture, and vaporous moisture remains in the compressed air. With further cooling of the compressed air, condensate reappears in it. Other methods are more efficient, but require consumables or complex devices for drying compressed air, which ultimately leads to an increase in the cost of such devices and an increase in operating costs. Based on the conducted analysis and on the fundamentals of theoretical mechanics, magnetic field theory and molecular physics, a method of magnetic-centrifugal drying of compressed air has been developed. The essence of the method is to use the Lorentz force, which acts on a water particle (a molecule, a dimer, a trimer, etc.) and coincides in the direction with the centrifugal force. When using the safe supply voltage of a 24 V solenoid that creates a magnetic field in which an electrically charged water particle moves, it is possible to increase the radial force (compared to the centrifugal force) acting on this particle by about 70 times. The authors also consider the methods of ionization of water particles that allow knocking out electrons from their outer shells. Experimental studies conducted on a mock-up sample showed a fairly high efficiency of this method, since it was possible to achieve the 3rd class of purity according to ISO 8573-1: 2001.

scholarly journals Air starting system of small-size gas turbine engine

2016 ◽  
pp. 61-66
Author(s):  
A. I. Kalinichenko
Keyword(s):  
Gas Turbine ◽  
Unmanned Aerial Vehicle ◽  
Experimental Studies ◽  
Turbine Rotor ◽  
Gas Turbine Engine ◽  
Rotor Blades ◽  
Compressed Air ◽  
Turbine Engine ◽  
Aerial Vehicle

To meet the requirements for starting a mid-flight (GTE) of a reusable unmanned aerial vehicle (UAV), we developed an air starting system according to the scheme with the direct feed of compressed air to the turbine rotor blades. The system is an alternative to the commonly used powder or electrical starting systems of a small-size GTE of UAVs. The paper gives the results of experimental studies to determine the reliable starting feasibility and methods for determining the parameters required for starting the GTE of UAVs.

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