Search Results

1 - 10 of 12 items

  • Author: Enikő Bitay x
Clear All Modify Search

Abstract

There are two concepts in the title that can be seen as “foreign” to the usual technical language. Both can have several meanings and thus we adapted them “flexibly” to the current needs. One way to understand the term “management” is through its functions: planning (defining purpose and means), organizing (defining tasks and methods), and direction (guidance, controlling), inspection (testing, comparing). It can also mean among other things, standpoint, circumstance, respect, or even character. Regarding the expression “damage management” the intended meaning here is reducing or to preventing damage to the tool, also improving the resistance of the tool material to damage, which besides material selection issues also has design, technology and operational aspects. This article gives an overview of some of these.

Abstract

In the middle of the 16th century the ironworks of Mădăraș was one of the important centres of iron production. During its one and a half century lifespan its output provided a significant part of Transylvania’s iron supply. While it operated it used up the entire raw material extracted in the iron ore mines of the Felcsík basin. This study presents the reconstructed ground-plan of the ironworks, its layout on the shores of the Mădăraș creek, and the chemical composition and microstructure of the samples discovered during exploration of the location by means of XRF analysis, EDS analysis and metallography. The analysis of the pig iron, the steel and the slag although performed on individual samples, still provides a good approach regarding the products of the ironworks, their chemical composition and microstructural characteristics.

Abstract

Archaeological publications connect the raw material used for the production of copper and bronze artifacts discovered during the excavations carried on in Szeklerland to the use of the chalcopyrite from the Bălan copper ore deposit. So far, this assumption has not been confirmed by concrete evidence. Men of the Bronze Age can’t possibly have had knowledge of the metallurgy of sulphide-type copper ores such as chalcopyrite. Applying investigations based on spectroscopy, the Bronze Age use of chalcopyrite from Bălan could be either confirmed or refuted, the new data throwing more light on the provenance of the bronze artifacts discovered in the Szeklerland.

Abstract

The technological advantages of ultrasonic welding: (no requirement for filler metal; use of small electrical transient resistance contacts; ability to weld thin materials to thick materials) results in a helium-solid weld seam; the computer configuration of the welding parameters can easily be solved; clean and safe workflow (no sparks, flame or smoke); can be integrated into the production line. This article deals with some of the additional application features of this welding process.

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.

Abstract

The laser processing of materials which are highly reflective at laser wavelengths is problematic. We have to take into account that only a small part of the energy is absorbed, the main part being reflected. In this article we examine the laser processing of highly reflective copper and silver at 1070 nm wavelength. In laser drilling of printed circuit boards it is necessary to drill copper layer as well. In highly reflecting materials we can drill smaller holes because of the low energy efficiency. Naturally in single pulse laser drilling the focus position plays a key role: at the focal spot of the laser beam smaller diameter holes are produced, further from the focal spot, higher diameter holes are produced.

Abstract

In this article investigation of the roles of two important factors of focused laser beam, the focal spot diameter and the Rayleigh length as determining variables of the beam quality were made. The equations of these two factors are based on those most commonly used in the literature. The exchange between three different beam quality numbers were shown. It is proven on the basis of the scientific literature, that the beam quality degrades compared to the original data given by the factory of laser. The causes of the beam quality degradation are lens aberrations in the optical path of the given laser, and the shifting of the beam propagation ratio (M2) to higher values. A new equation for estimation of the new, lowest value for M2 factor is presented, based on the comparison of the laser cut material thickness to the depth of focus, which is two times the Rayleigh length.

Abstract

Proper management of the realization of the general and special training objectives of technical higher education makes it necessary to organize the curriculum and the educational process according to didactic, methodological aspects. Selection of curriculum elements with deductive and inductive approach and their horizontal and vertical arrangement are required. In addition, the curriculum concentration of a given subject, i.e. its connection to other subjects, must be taken into account. This article intends to add to this by raising some points.

Abstract

The choice and the appropriate combination of methods used in the teaching-learning (education – knowledge-acquisition) process in technical higher education depends to a large extent on the personality of the lecturer, his/her pedagogical culture, personal competences and of course, the technical possibilities at his/ her disposal. This study provides a concise overview of the methods as tried-and-tested systems of consciously implemented operations and means that are systematically used by the lecturer to achieve the objectives of training in practical cooperation with the students.

Abstract

The effective recycling of polymer materials remains unresolved to this day, and this has had a devastating effect on the environment. This study examines an alternative method to PET recycling that is the generation of polymer fibers and fiber mats for filtration applications. The electrospinning instrumentation used in this study had to be designed and built in order to carry out the research. We have managed to produce PET fibers with 200-600 nm diameter, and free-standing fiber mats that could potentially be used in filtration applications.