Papers by Author: Márton Takács

Abstract: Concrete is the strongest candidate to be the most important construction material of the 21st century. This can be ensured by the continuous research and development of new materials and technologies regarding concrete construction. Properties of concrete can be expediently modified by adding special chemical materials called admixtures. In this research work effect of type and dosage of different superplasticizing admixtures available in Hungary were investigated in detail. Standard test methods such as flow table test and compressive test were applied to obtain effectiveness of the admixtures. Regarding the examinations done in the course of the research, we refer to the regulations of the EU harmonized admixture standard currently valid in Hungary MSZ EN 934-2:2002. In connection to that we will precisely quote the requirements specified in the standard regarding superplasticizers and will also mention the main differences compared to the plasticizer additives. Types, properties and use of superplasticizers are introduced in detail, too. Experimental results are evaluated to rate the efficiency in compliance with the requirements of the standard.

Abstract: There is no doubt that concrete makes a massive contribution to sustaining the quality of life. Properties of concrete can be expediently modified by adding special chemical materials called admixtures. Admixtures for concrete are now widely accepted as materials that contribute to the production of durable and cost-effective concrete structures [1]. Plasticizing admixtures reduce water needed to achieve a given workability of the fresh mix. This main effect can be utilized in three ways: increased strength, increased workability, or economies in mix design [2]. In this research work effect of type and dosage of different plasticizing admixtures available in Hungary were investigated in detail. Standard test methods such as flow table test, compressive test, and shrinkage test were applied to obtain effectiveness of the admixtures. Results were compared with the requirements of the harmonized admixture standard MSZ EN 934-2:2002.

Abstract: Miniature structures can be produced economically by micro end milling as single parts or parts in small and medium lot sizes. The micro end milling process has to be analyzed particularly for the purpose of applying a well controlled and repeatable process. There are many specific characteristics in the micrometric scale of dimensions, whose role is negligible at the conventional processing technologies. One of these special features of micro end milling is the observation that the set value of the feed rate per tooth generally differs from the thickness of the actual removed material layer. Feed rate per tooth is practically defined as the distance, which is run by the edge lengthwise of the groove during one revolution of the tool. Accordingly the feed rate per tooth corresponds to the thickness of the material layer removed by one edge of the tool. This correspondence exists at conventional manufacturing methods but not at micro end milling. This fact is attended by more special features of the micro end milling process, which are multiple cutting, different machining conditions of the edges and tool deflection. This paper introduces the results of improvement of my earlier research on this field [1]. An enhanced flowchart was constructed, which provides the calculation of the thickness of the actual removed material layer at micro end milling under all possible circumstances.

Abstract: Amorphous and partly nanocrystalline amorphous iron-phosphorus (Fe-P) layers have been deposited by pulse electrochemical technique. X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) have been used to characterize the structure in the layers. Depending on the pulse parameters, the structure of Fe-P layers changed from mostly amorphous to partly nanocrystalline amorphous. The magnetic coercivity and the frequency limit of the samples are discussed in terms of the structure of the Fe-P layers. The frequency limit as determined from the permeability spectra is above 10 MHz, which makes these layers suitable for high frequency inductive element applications.