Solid State Phenomena Vol. 199

Abstract: One of the most important physical quantities which has an influence on bearings and micro-bearings functioning is the viscosity of a lubricant. The data about a viscosity value dependence on temperature and shear rate are essential for designing sliding friction pairs. In design calculations usually there is assumed that a lubricant is a Newtonian fluid, therefore viscosity is constant over the full range of shear rates. During operation of friction pairs the contamination particles get into a lubricant and this causes that the lubricant becomes a non-Newtonian pseudoplastic or viscoelastic fluid. A similar effect on lubricating oil properties have combustion products or special performance additives. Furthermore, a lubricating oil ages and wears out, i.e. during its operating the initial structure of a particles is destroyed which can cause the change of the oil viscosity and lubricity values. The aim of this work is to determine the dynamic viscosity values in dependence on temperature and shear rate for selected new and used lubricating oils. In this research motor oils for passenger vehicles and tractors were investigated. This paper presents the results of measurements of the viscosity changes, in dependence on shear rate and temperature, made for the new and used oils. One of the investigated oils is Superol CC-40, which was used in four-stroke 4562 cm³ diesel engine for twenty months, which corresponds to 250 hours of operating. The second of investigated oils is Shell Helix Ultra AV-L which was used in four-stroke 2000 cm³ diesel engine for ten months at a distance of 15 000 kilometers. The viscosity measurements for the new and used lubricating oils were made with the Thermo Scientific Haake Mars III rheometer, in the range of temperatures from 10°C to 120°C and of shear rates to 51000 1/s. Moreover, the analysis of wear products, contaminants and additives in the investigated new and used lubricating oils was made with the rotating disc electrode atomic emission spectrometer Spectro Incorporated Spectroil Q100, which gives possibility to determine 22 most common elements which occur in motor, turbine and gear oils. The obtained information will be used in future studies related to hydrodynamic lubrication of slide bearings and micro-bearings. It also may be useful for designing bearings and sliding friction pairs.

Abstract: Lapping leads to a surface with low roughness and high precision. Because of required parts accuracy tool flatness is the key to the successful machining. To avoid its excessive thermal expansion, plate temperature research was taken. The goal was to determine the correlation between the basic lapping conditions and wheel temperature. In work [1] authors developed model to estimate the maximum and average temperature rise of the work surface in lapping. According those models temperature rise depends also on workpiece and plate hardness. Because the second is constant during process, this part of research refer only to the influence of workpieces hardness. They were conducted during lapping the samples made of steel 45. To vary the hardness, samples were divide into three groups each with different Knoop hardness value: 175, 471 and 687. The different hardness values were a result of different heat treatment methods used. Every group after grinding were lapped with the same lapping conditions. In the next step the statistical analysis was conducted. It was verified if the plate temperature is influenced by the workpieces hardness. A hypotheses testing method was use. Results were calculated for temperature rise values measured after 300 minutes of machine working. According to them the influence of workpiece hardness on plate temperature is statistically insignificant.

Abstract: The article presents tribological aspects in the process of aperture shaping using trepan drills. These tools, also known as trepan cutters, are used for performing port apertures. Due to their structure, only peripheral part (ring) of the aperture is influenced by the milling process, in contrast to milling the whole volume when using twist drills. Due to such method of performing aperture, the power and processing time are significantly reduced. The results of this process are chips and the core that can be used to produce other element, particularly if the material is expensive or if it can be used to examine properties and quality of the material. Trepan drills contain at least four cutting edges and their number increases with the diameter of the tool. This results in forming many chips that interact with the tool and working material during their movement along the chip grooves. During operation of these tools, the tool makes contact with the core and working material. Above effects cause the increase of milling torque and axial force with increasing penetration of the tool into working material and may affect the quality of the created aperture (roughness, microhardness, chemical composition, shape tolerance). In the extreme cases they may also cause the stoppage of device used to drilling or destruction of the milling tool. The article presents also the structure of research station that was used for examination and obtaining sample results of the milling torque and axial force occurred during drilling using trepan drills. Additionally, the values of milling torque and axial force calculated on the basis of theoretical equations are presented. Physical model of the friction process describes, besides effects that occur in the milling area, also other factors that influence the course of the drilling process. The result of drill penetrating the working material is the increase of milling forces, axial forces and temperature. The cause of this effect is the friction between internal and external tool surfaces and the working material, as well as the friction between formed chips and the tool and working material during their movement along the chip grooves. Physical model was the output element to create mathematical model that includes, besides milling force, also forces occurring as a result of interaction among the tool, working material and chips. Additionally, the model includes forces that occur when pressing guide pin to working material.

Abstract: This work investigates agglomeration process of aerosol particles in presence of acoustic field. It is shown that besides orthokinetic and hydrodynamic interaction mechanisms, tribological interaction occurs in presence of acoustic field. This interaction depends on dynamic viscosity of the gas mixture above the liquid surface. The influence of acoustic field on tribological interaction between the aerosol particles was investigated both numerically and experimentally. The obtained results show the positive influence of acoustic field on agglomeration of aerosol particles.

Abstract: The paper represents the results of investigations conducted on the tribological test for the conditions of the friction of technically dry. Analysis stereological counter-specimen was subjected from AOC and AOC modified sealed up the polymers that is composites coats. Polymerization occurred at a temperature below the recrystallization temperature of the alloy EN AW 5251. The values of the coefficient of the friction, and the results of investigations AFM (atomic force microscopy) and the parameters of the roughness were compared. The tribological properties composites are investigated by using the pin-on-disk type rotational wear tester T-01 M. This paper shows models 3D of the AOC modified polymer and the mechanism of wearing. Tribological measurements show reduced wear and friction of the composite coatings as compared with the pure anodic oxide

Abstract: The paper presents a modification of the structure of a biological neural network (BNN) based on spiking neuron models. The proposed modification allows to influence the level of the stimulus response of particular neurons in the BNN. We consider an extended, three-dimensional Hodgkin-Huxley model of the neural cell. A typical BNN composed of such neural cells have been expanded by addition of resistors in each branch point. The resistors can be treated as the weights in such BNN. We demonstrate that adding these elements to the BNN significantly affects the waveform of the potential on the membrane of the neuron, causing an uncontrolled excitation. This provides a better description of processes that take place in nervous cell. Such BNN enables an easy adaptation of the learning rules used in artificial or spiking neural networks. The modified BNN has been implemented on Graphics Processing Unit (GPU) in the CUDA C language. This platform enables a parallel data processing, which is an important feature in such applications.

Abstract: This study presents a new approach to determine significant prognostic factors for patients suffering from the bladder cancer. The analysis of medical data has been performed by the use of the Kohonen self-organizing map (SOM). The SOM allows visualizing and identifying the prognostic factors indicating which of them are significant. A database comprised of ninety patients has been used in this study. Seven predictors were investigated. The cluster analysis indicates that the significant prognostic factors for the bladder cancer are: histological grade (cG) and stage (cT). The obtained results also showed that the sex and the cG variables are highly correlated and that the number of non-classic differentiation (NDNc) features in bladder cancer is somewhat correlated to surgically removed lymphnode number (LN) and metastatic positive lymphnode number (PLN).

Abstract: Application of machine vision in automation, robotics and mechatronic systems is one of the most rapidly developing areas of industrial and applied computer science. The vision system presented in the paper can be used for automatic positioning of the workpieces on the numerically controlled machines. The idea of the system is based on the 3D scanning using the fringe patterns approach [ but its accuracy strongly depends on the lighting conditions and the proper calibration of the whole vision system. The most crucial elements for the calibration are both cameras and structural light projectors, as well as the overall geometrical configuration (external parameters in the common coordinate system) and the compensation of the brightness nonlinearities introduced by the structural light sources. In the paper some methods used for the calibration of the experimental system and obtained results are presented.

Abstract: This article is devoted to the methods of image analysis used in three-dimensional vision systems. Based on a sample set of 3D images, their defects resulting from the adopted three-dimensional image construction technique are discussed. Those defects are discussed in relation to the following parameters: speed of the vision system, power of the laser, laser mode, laser arrangement relative to the vision system sensor and relative to the tested surface. To illustrate the cases discussed, images showing the effects of selected parameters on the quality of mapping of the tested object onto a three-dimensional image were presented. The next part of the article discusses methods of range image filtering that removes or reduces the importance of defects of the adopted method in any control and measuring tasks. Particular attention is given to methods of removing data described as missing data.

Abstract: In robotic systems navigation, it is necessary to determine the direction, in which the local coordinate system of a robot is to be turned in regards to the reference, global system. That direction from mathematical point of view is the rotation along one axis of the reference system, such that the reference system coincides with the local system associated with the body, which direction is defined. There is an assumption that the rotations along two other axes do not exist or they were taken into account in the calculations. A question appears: what is the measurement of the direction based on The answer to that question is provided by nature [1, , because it has already solved this problem long ago. In migratory species such as birds, bees and fish, evolved magnetoreception abilities which allow an animal to detect the magnetic field of Earth. These abilities enable such organisms to navigate in space. In many devices magnetic field sensors called magnetometers are already used. However, magnetic measurements are subject to many kinds of distortions and errors. This paper shows a practical approach to a robot navigation problem.