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  • Koszałka, Grzegorz (Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie, 2010)
    The share of start-up wear in total wear of an automobile engine is large, and in the analysed case it exceeded 40%. The amount of start-up wear of engine elements strongly depends on start-up temperature: the lower temperature, the larger wear. Hence the particular significance of so-called cold start-ups, which most often are first starts of an engine on a given day. The temperature of the first start-up in ungaraged vehicles is the same as the temperature of the surroundings, and it depends on the season. This article analyses changes in mean intensity of wear of a truck engine cylinder liner associated with different temperatures of first start-up in different seasons. In the analysed case, the intensity of wear in winter was 16% higher than in the summer. Also discussed are the possible consequences of the above changes for wear intensities determined in measurements
  • Sidun, Jarosław (Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie, 2010)
    The internal fixation of maxillofacial fractures with plates and distracters has gained growing popularity during the last decades. The design of implants for fracture fixation has undergone a gradual evolution over the years as researchers have tried to facilitate healing and decrease the rate of complications. Osteolysis is one of the foremost problems limiting the survival of current implantation procedures. It is induced by the wear particles and corrosion products which incite an inflammatory response resulting in bone resorption and eventual loosening and failure of the bone fixation. The future research will help to limit the effects of wear particles by identifying the most suitable bearing surfaces. The pathologic cascade of events triggered by wear particles may be a potential site of action for drugs intended to prevent or check the progression of the disease. The paper presents a damages problems of the maxillofacial plate fixation. The surface failure at plate stabiliser elements showed typical damages for this system. Damages of screw’s steepl heads as well as the surface layers failure of the the coned seat on tie plates were observed. The surface failure at a screws were visible in a lesser degree. The biggest wear areas are visible on the cooperating surfaces of the plate sockets and the bone screw heads. Many types of damage characteristic of processes of corrosion damage and tribological wear, mainly abrasive, adhesive, and fretting wear, are observed here
  • Girtler, Jerzy (Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie, 2012)
    The paper shows a necessity to consider the processes of load on and wear of tribological systems in Diesel engines (and therefore the changes in their states) in real conditions as random processes. This means that mathematical models for these processes can be random functions with an argument which is time (t) and with values which are random variables such as loads and wear of particular tribological systems. The load properties for the tribological systems have been presented as the main causes of their failures. It has been signaled that a stochastic dependence should be expected between mechanical load and thermal load, whose the intensity (force) can be defined by Czuprow’s convergence coefficient. A proposal has been submitted to accept that the tribological system load in Diesel engines is a stationary process with asymptotically independent increments. The reasons for this proposal have been presented in the form of relevant hypotheses and an exemplary graph of changes in pressure and temperature in an engine cylinder under operation. Also it has been signaled that the models of wear processes in tribological systems may be stochastic processes with special properties called semi-Markov processes. The wear properties for these systems have been explained in the form of relevant hypotheses
  • Treichel, Piotr (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    The paper presents basic information on wear process. The engine scavenge air system has been described and observation data have been presented. Based on trend analysis and statistic methods, mutual relations between selected parameters have been presented.
  • Sharifov, Zahid; Aliyev, Chingiz (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    The article deals with the influence of surface roughness, processed by various technological methods, on the wear-resistance characteristics of the surface layer of high-precision parts of ship machinery and mechanisms. It considers various technological methods of processing parts; rotary cutting, grinding with vibration damping, rotational honing, grinding with metered removal of surface material and elastic rolling. It was found that the application of rotational boring as a method of finishing not only forms an additional, highly wear-resistant surface layer on the surface of the parts, but also provides high productivity. The process of grinding with vibration damping significantly reduces the transfer of abrasive particles to the surface being treated, and improves the accuracy, quality and wear resistance of the surface layer. On rotational honing, the discontinuity of the cutting of individual grains is combined with the continuity of the chip formation process; the metal does not adhere to the working surface of the cutting part of the tool, and the temperature in the cutting zone decreases, resulting in a high-quality, wear-resistant surface layer on the parts. When lapping with dosed removal of the material of the surface layer, the optimum thickness of the highly-deformable surface layer is ensured, due to the possibility of controlling the abrasive action on the surface to be treated, which promotes the formation of a reliable, wear-resistant layer. Elastic rolling allows processing of non-rigid, thin-walled parts by stable, balanced, controlled forces, without reducing their accuracy, quality and wear-resistant characteristics.

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