Magnetoplasma compressor (MPC), a type of plasma accelerators, is used for treatment and alloying of steel samples: steel 100Cr6, steel 16MnCr5 and steel 42CrMo4. The high-speed plasma flow formed ...within the MPC, from helium with 5% of hydrogen as working gas, is directed to the surface of the samples. The energy flux density of the plasma flow in the plasma-sample interaction area is 9 Jcm2. Plasma melts the near-surface layer and during the rapid cooling process, a thin layer with structure different from initial is created. Changes in the physical composition of the substrate are monitored depending on the number of plasma treatments. After treatment with a plasma produced within MPC, a significant improvement of hardness has been achieved.
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•Steel surfaces are treated with plasma formed within a special type of plasma accelerator: magnetoplasma compressor (MPC).•Every plasma shot deposit 9 J/cm2 of energy to the surface of the treated material.•Hardness of steel 100Cr6, steel 16MnCr5 and steel 42CrMo4 is improved after treatment with plasma produced in MPC.•Smoothing of the peripheral region of the surface microrelief occurs after a sufficient number of the plasma treatments.•There is a phase change from a singly α-Fe to combination of α and γ-Fe after steel 100Cr6 has been treated with plasma pulses.
Industry 4.0 in Serbia: State of development Majstorović, Vidosav; Mitrović, Radivoje; Mišković, Žarko
Serbian journal of management,
01/2022, Letnik:
17, Številka:
1
Journal Article
Odprti dostop
A new model of automation of technological systems, based on the Internet, was defined as the concept of Industry 4.0, Germany in 2011. It represents an advanced model of connecting machines and ...computers (cyber-physical systems - CPS), their networking (cloud computing and Internet of Things (IoT)) with the widespread use of advanced artificial intelligence (AI) in this concept. This concept is a model of smart manufacturing (SM), and today we are talking about: smart vehicles, smart highways, smart grids, smart cities, smart services, etc ... - in short, intelligent "everything and anything" (smart everything). The most important directions for Serbia in the application of Industry 4.0 include: industrial policy for Industry 4.0, education for Industry 4.0 (higher / secondary education), research for Industry 4.0, and especially applied research and readiness of SMEs for Industry 4.0, as well as the application of this model in practice. This paper presents the development and application of the Industry 4.0 model in Serbia, through the activities of the Faculty of Mechanical Engineering in Belgrade, from 2015 until today, with special reference to the application of Industry 4.0 in mining.
One of the most important factors influencing ball bearings service life is
its internal radial clearance. However, this parameter is also very complex
because it depends on applied radial load and ...ball bearings dimensions,
surface finish and manufacturing materials. Thermal condition of ball
bearings also significantly affects internal radial clearance. Despite many
researches performed in order to find out relevant facts about different
aspects of ball bearings thermal behaviour, only few of them are dealing with
the real working conditions, where high concentration of solid contaminant
particles is present. That?s why the main goal of research presented in this
paper was to establish statistically significant correlation between ball
bearings temperatures, their working time and concentration of contaminant
particles in their grease. Because of especially difficult working
conditions, the typical conveyor idlers bearings were selected as
representative test samples and appropriate solid particles from open pit
coal mines were used as artificial contaminants. Applied experimental
methodology included thermographic inspection, as well as usage of custom
designed test rig for ball bearings service life testing. Finally, by
obtained experimental data processing in advanced software, statistically
significant mathematical correlation between mentioned bearings
characteristics was determined and applied in commonly used internal radial
clearance equation. That is the most important contribution of performed
research - the new equation and methodology for ball bearings internal
clearance determination which could be used for eventual improvement of
existing bearings service life equations.
The impact of geometric parameters of teeth and lubricating oils to the efficiency of involute internal spur gears, when the transverse contact ratio is 2 < ?? ?3, has been analyzed in this paper. ...The mathematical model and computer program for determining the current and the effective value of the efficiency have been developed. The influence of the character of load distribution and energy losses due to heating effects during the meshing period is included in the factor of load distribution. The results of computer simulation are given in the form of a diagram of the current values of the efficiency during the meshing period. Also, the values of effective efficiency for the considered cylindrical gear pairs have been calculated.
nema
The research of influence of operation temperature on the thermal expansion
and main parameters of radial ball bearings is presented in this paper. The
main bearing parameters are identified in ...accordance with the increasing
requests concerning stability and load capacity. A series of Finite Element
Analyses is performed for quasi-static analysis of all identified bearing
parameters during contact period in referent temperature. Then, the
dependence of bearing material characteristics on the operation temperature
is discussed. Few series of Finite Element Analyses are performed for a
particular radial ball bearing type, with characteristics in accordance with
manufacturer specifications, for several operation temperatures. These two
problems analyses include consideration of relation between the initial
radial clearance, thermal expansion strains and contact deformations of the
parts of the bearing assembly. The results for radial ball bearing parameters
are monitored during a ball contact period for different temperatures and the
appropriate discussion and conclusions are given. The conclusions about the
contribution of developed procedure in defining the optimum operation
temperature range are shown.
The research of the influence of housing material on operation temperature of the idler bearing assembly is presented in this paper. Several radial loads and rotary speeds were applied to the test ...bench to determine the transient temperature field. The results were monitored and recorded for the whole period until the temperature of the assembly reached stationary stage. The FEM model was created where the rolling elements were replaced with the especially designed artificial body, having the shape of irregular ring. It generates heat and connects only those points of the inner and outer ring which are in operating conditions connected with the rolling elements. The experimental results are compared with FEM results. The conclusion is given on suitability of polymer material for this purpose.
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