Algirdas Vaclovas Valiulis

Engineering Education Quality Assurance: The Essential Pillar of Higher Education Reform in Lithuania

The purpose of this chapter is to present a review of Lithuanian engineering education and its related evaluation and accreditation systems. Lithuanian engineering education has changed dramatically in recent years: initially in 1991 after Lithuania separated from the Soviet Union, then in 1999 when Lithuania accepted the Bologna process and very recently in 2004 upon Lithuania’s entry into the European Union. This chapter examines the strengths and weaknesses of the current educational system and, in particular, the assessment of engineering education in the hope that it will enable the further integration of Lithuanian engineering education into the European Higher Education Area. With the 2010 deadline for implementation of the Bologna Process approaching Lithuanian higher education, it is attempting to provide responses to the following questions: What current challenges will persist well into the next few years? Where is European higher education heading? What opportunities is Lithuania facing in an increasingly globalised World?

Investigation of Cathodic Cleaning Processes of Aluminum Alloy

On covering aluminum and its alloys with coatings resistant to high-temperature corrosion and attrition, abundant technological problems arise. The key problem is a removal of the film of aluminum oxide Аl2O3 from the aluminum substrate. This permanent, chemically continuous film of oxide reduces adhesion between the substrate and the coating. For improving cohesion of the coating with the substrate, an appropriate pre-treatment of aluminum is required. In the paper, cleaning of aluminum alloy AW 5754 by electric discharge is investigated. This method is considered one of most environmentally friendly methods of surface cleaning. The impact of the parameters of aluminum alloy cathodic cleaning on the surface cleaning width, its roughness and free energy of the surface were examined. In addition, the topography, microstructure and chemical composition of the surface of cleaned aluminum alloy were estimated.

Effects of Vibration Energy Input on Stress Concentration in Weld and Heat-Affected Zone of S355J2 Steel

The existence of residual stresses induced by the welding process is an important reason of cracking and distortion in welded metal structures that may affect the fatigue life and dimensional stability significantly [1]. Heat treatment is one of the traditional methods to relieve the residual stresses. But it is often limited by the manufacturing condition and the size of the structures. In this paper a procedure called vibratory stress relief (VSR) is discussed. VSR is the process to reduce and re-distribute the internal residual stresses of welded structures by means of weldment mechanical vibration during welding. Parameters of VSR procedure are described in the paper. Residual stresses on weld bead are measured in three different specimens by X-ray diffraction method. Mechanical tests of welded specimens were also performed with purpose to evaluate VSR effect in weld metal and heat affected zone (HAZ).

Effect of PWHT on the Mechanical Properties of P5 Steel Welded Joints

Presented work analyses the impact of heat treatment parameters on the mechanical properties and operational reliability of P5 (5%Cr0.5%Mo) steel welded joints. The key objects of research are heat-treated chrome-molybdenum steel welded joints and piping elements operated at high temperature for an extensive period of time, where degradation of mechanical properties has been observed. The main objective is to investigate the causes of degradation of alloy steel mechanical properties during fabrication and operation of the equipment, and to develop a methodology for identification of optimum heat treatment parameters for chrome-molybdenum steel welded joints. A few key issues are addressed herein: identification of dependence of chrome-molybdenum (5%Cr-0.5%Mo) steel welded joint mechanical properties on heat treatment parameters, identification of the optimum value of temperature/time parameter, and identification of causes of mechanical property changes and degradation of the steel.

Operation Reliability of Bent Elbows of Steam Pipelines

The number of potentially dangerous equipment that has completed its established operational time, but is still being used, is permanently increasing. Therefore there is a problem of its further operations. A decision to continue to operate power-generating plants, when the initial resource of the equipment’s working time is ended, and its further operation without considerable expenditures on repair and the diagnostic of a metal state is possible only with the help of long-term research of metal in power-generating plants. Only a complex of research techniques can estimate the real state of a construction. In the article problems connected with the definition of operation reliability of steam pipeline elbows are investigated. Different areas of an elbow were researched. Results of a microstructure analysis, and mechanical characteristics (time history) research of an elbow metal are presented. Also results of calculation of an elbow on low - cyclic thermal fatigue are presented.

Preparing Al-Mg Substrate for Thermal Spraying: Evaluation of Surface State After Different Pretreatments

The article deals with the pretreatment technique for preparing the surface of aluminum alloy EN AW 5754 before thermal spray. The surface after different pretreatments, including degreasing with acetone, chemical etching with acidic and alkali solutions, grit-blasting, cathodic cleaning, and some combinations of these techniques, has been studied. The investigation of pre-treated surfaces covered the topographical study (using scanning electron microscopy, atomic force microscopy, and 3D profilometry), the chemical analysis by x-ray photoelectron spectroscopy, the evaluation of surface wettability (sessile drop method), and the assessment of surface free energy. Compared with all the techniques used in present work, the cathodic cleaning and its combination with grit-blasting provide the most preferable chemistry of the surface. Due to the absence of hydroxides at the surface and, possible, due to the diffusion of magnesium to the surface of substrate, the surface wettability and the surface free energy have been significantly improved. No direct correlation between the surface topography and the surface wettability has been established.

A History of Materials and Technologies Development

1502-S ISBN 978-609-457-740-6 Algirdas Vaclovas Valiulis Dr Habil. ALGIRDAS VACLOVAS VALIuLIS is a professor of Vilnius Gediminas Technical university in Lithuania. He has published numerous papers on arc, plasma, laser, resistance welding of ferrous and nonferrous structural materials, arc, spray and PVD surfacing or coating, heat treatment of welded structures. He is the author of books Alloy Steel and Their Welding, Advanced Materials, Engineering Materials: Science, Properties and Applications, etc., a full member of Lithuanian Academy of Science and a national representative in the European Steel Technology Platform and the Research Fund for Coal and Steel. Prof. Valiulis has been awarded a professional diploma of an International Welding Engineer from the International Institute of Welding. This book is his first attempt to be involved in the space of the history of developing technologies. A lgrdas Valovas Viulis

The Research of Thermal Arc Sprayed Coatings Tribological Properties by Using Rubber Wheel Test

This paper present the result obtained from new experimental STEIN-MESYFIL 953 V; STEIN-MESYFIL 954 V coatings. The surfacing material was wires of 1.6 mm diameter. The tests aimed at determining wear resistance of coatings sprayed on steel substrate. The investigation shows that the tribological behaviour of new experimental thermal arc sprayed coatings is greatly affected by its microstructural constituents such as porosity, oxide inclusions, and microhardness of coatings. Results show that increasing porosity of coatings twice, it doubles the mass loss. Results for thermal sprayed coatings of all experiments showed their high wear resistance and are discussed.

Strengthening Mobility for Better Learning

In a modern environment, during the evolution of international activities, from mobility to international education hubs, universities are searching for new internationalization tools to implement those undertakings more effectively in terms of finance and time. Co-operation with other regions of the world and international openness are the key factors in the development of the European Higher Education Area. To illustrate the situation arising from student mobility of studying technological sciences, the paper analyses information about student mobility in the fields of mechanical engineering and mechatronics for the period 2009–2013.

About the Possibility of Using Ultrasound in Thermal Spray Technologies

The present article introduces a survey on ultrasonic technologies applied to material processing and describes the possibilities of improving the quality of coating made by thermal spraying introducing ultrasound into the covering process. The article contains the results of some other research works and discusses a number of conclusions about the possibilities of applying ultrasound in thermal spray technologies.