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Materials Science and Engineering – Some Aspects in Central and Eastern European (CEE) Countries

Abstract

This introductory paper summarizes the characteristics of how “Science” and “Engineering” differ from each other, forming the interdisciplinary topic of Materials Science and Engineering (MS&E). It will be shown how microelectronics has developed from modern materials science, causing a change in paradigm, and how microelectronics has become the “mother” science of informatics, changing life on Earth. To prove the importance of materials, a table is shown summarizing how modern MS&E forms the basis of practically all industries. The situation and development state of MS&E in CEE countries - despite different levels of industrialization – have some characteristics in common, and the way to development might also have techniques in common.

We will also mention the knowledge base that CEE countries possessed during the period of political change, and the likely future that an elderly scientist foresees for the region with the help of young ambitious scientists.

Open access
Metal Foam Analysis Based on CT Layers

Abstract

The geometrical modelling of metal foams remains one of the greatest challenges facing researchers in the field. In this paper the analysis of the inner structure of closed-cell aluminium foam - an essential part of the construction of an idealized foam model - is presented. With the application of special purpose software the properties of the foam cells can be mapped precisely and the results applied to the development of idealized foam geometry constructed in CAD applications.

Open access
Method for Emissivity Estimation of Metals

Abstract

Knowledge of the surface emissivity of metals is becoming more and more important both from the material science, process modelling and control point of view. Previous research results have shown that the emissivity of most metals depends on the temperature of the surface. It has also been reported that the most important temperature region is between 300 – 1000 K degrees, where the change of the emissivity is the most intense, which is also the most significant from a process control point of view [1]. We also report temperature dependent emissivity observed during plasma nitriding of low alloy steels [2]. Related to one of our present research topics the study of the low alloy aluminum (AlMg1, AlMg3) emissivity has prooven relevant. In this article the developed emissivity estimation model is presented. In the first part a literature overview and the theoretical approach of the new method is discussed, followed by the experimental results for low alloy aluminium emissivity determination and a comparison with the results available in the literature.

Open access
A New Method for Determining the Pullability of Composite Reinforcing Ceramic Fibres

Abstract

A unique method for producing aluminium matrix composite wires is the Blücher’s process, i.e. continuous gas-pressure infiltration. An essential condition of the process is that the fibre roving of the reinforcing fibres can be pulled across the orifices of the gas-pressure system with the least damage. The article describes a new test procedure that is capable of characterizing this essential functional property of the ceramic reinforcing fibres in a manner comparable and quantitative.

Open access
Surface Roughness Effect in the Case of Welded Stainless Steel Corrosion Resistance

Abstract

It is known that fusion welding can cause a decrease in the corrosion resistance of the heat affected zone of unstabilized stainless steels. The reason for this problem is that the welding heat (in the heat affected zone (HAZ)) can cause chromium-carbide (Cr23C6) precipitation with the simultaneous reduction of chromium content at the local grain boundaries. The chromium content dictates the corrosion resistance level. The relationship between surface roughness and corrosion behaviour is well known. We sought to find the difference between the corrosion resistance and surface roughness relationship in the case of cold rolled stainless steel and in the case of heat treated (welding heat effect simulated) stainless steel [1-3].

Open access
Comparison of various tool wear prediction methods during end milling of metal matrix composite

Abstract

In this paper, the problem of tool wear prediction during milling of hard-to-cut metal matrix composite Duralcan™ was presented. The conducted research involved the measurements of acceleration of vibrations during milling with constant cutting conditions, and evaluation of the flank wear. Subsequently, the analysis of vibrations in time and frequency domain, as well as the correlation of the obtained measures with the tool wear values were conducted. The validation of tool wear diagnosis in relation to selected diagnostic measures was carried out with the use of one variable and two variables regression models, as well as with the application of artificial neural networks (ANN). The comparative analysis of the obtained results enable.

Open access
Accuracy and repeatability positioning of high-performancel athe for non-circular turning

Abstract

This paper presents research on the accuracy and repeatability of CNC axis positioning in an innovative lathe with an additional Xs axis. This axis is used to perform movements synchronized with the angular position of the main drive, i.e. the spindle, and with the axial feed along the Z axis. This enables the one-pass turning of non-circular surfaces, rope and trapezoidal threads, as well as the surfaces of rotary tools such as a gear cutting hob, etc. The paper presents and discusses the interpretation of results and the calibration effects of positioning errors in the lathe’s numerical control system. Finally, it shows the geometric characteristics of the rope thread turned at various spindle speeds, including before and after-correction of the positioning error of the Xs axis.

Open access
Influence of Water on Tribological Properties of Wood-Polymer Composites

Abstract

Utilization of ecological materials for appliances and products is one of the ways to achieve the goal of sustainability.Wood-polymer composites as a cheap, lightweight, durable and esthetic material has gained attention of scientists, engineers and consumers alike. Different kinds of polymeric matrices, plants used as the fillers, chemical of physical modifiers and processing technologies have already been widely studied. Nonetheless, surprisingly few information on Wood-Polymer Composites’ tribology can be found. This paper is an attempt to fill this gap. Polypropylene-and poly(lactic acid)-based composites with varying wood flour content have been analyzed. The Brinell’s hardness and coefficient of friction of the samples have been determined. In order to evaluate the influence of the moisture content on the tribological and mechanical properties of the composites, the samples have also been aged in water. The investigation revealed that polymeric composites filled with wood flour can present favorable coefficient of friction, compared to the neat resins. The results of our study can establish a good starting point for further investigation.

Open access
Design of The Test Stand for Hydraulic Active Heave Compensation System

Abstract

The article presented here described the design of a test stand for hydraulic active heave compensation system. The simulation of sea waves is realized by the use of hydraulic cylinder. A hydraulic motor is used for sea waves compensation. The hydraulic cylinder and the hydraulic motor are controlled by electrohydraulic servo valves. For the measurements Authors used displacement sensor and incremental encoder. Control algorithm is implemented on the PLC. The performed tests included hydraulic actuator and hydraulic motor step responses.

Open access
Diagnostic methods of detecting defects within the material with the use of active infrared thermovision

Abstract

Article presents the methods of detecting defects within material with the use of active infrared thermovision. During the study ABS and PVC samples were used inside which internal structure defects and defects of glue conjunction between components were modeled. During combining composite materials with the use of glue joints, there is a problem with homogenous distribution of the glue layer on the surface of an element, which results in the creation of defects in joint structure and the decline of active surface of adhesion forces on the combined materials. It is then necessary to control the quality of the conjunction between the glued surfaces. The use of non-contact diagnostic methods allows to analyze a larger surface which conditions in more efficient quality control process. In the study, external heat excitation was used - optical excitation with periodic variable signal (LockIn method) and unit step excitation (Pulse method). The methods of analysis of the obtained thermograms are presented.

Open access