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1

Investigation of Multicomponent Lead-Free Solders

Gyenes A., Benke M., Teglas N., Nagy E., Gacsi Z.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 2B

1071--1074

EN

According to the directives (RoHS and WEEE) adopted by the European Union, lead has been banned from the manufacturing processes because of its health and environmental hazards. Therefore, the development of lead-free solders is one of the most important research areas of the electronic industry. This paper investigates multicomponent Sn-Ag-Cu based lead-free solders with different compositions. The properties of the six-component Innolot (SAC+BiSbNi) and two low-Ag containing alloys were compared with the widespread used SAC307 solder. Microstructure investigations and X-ray diffraction measurements were performed to analyze and identify the formed phases, furthermore, tensile tests and microhardness measurements were executed to determine the mechanical properties of the examined solders.

2

Preliminary results of radon survey in thermal spas in V4 countries

Műllerová M., Mazur J., Blahušiak P., Grządziel D., Holý K., Kovács T., Kozak K., Nagy E., Neznal M., Neznal M., Shahrokhi A.

Nukleonika

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2016

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Vol. 61, No. 3

303--306

EN

Radon concentration was measured in 11 thermal spas in Visegrad countries (Czech Republic, Hungary, Poland, and Slovakia). The results showed that in 84% of spas radon activity concentration is less than 400 Bq·m–3. However, areas with radon activity concentration exceeding 1000 Bq·m–3 were found in the Czech Republic and Slovakia as well. Preliminary analyses indicated that the highest radon activities in spas were found in places with thermal pools. Radon concentration in waters used in spas ranged from 0.5 Bq/l to 384 Bq/l. The influence of radon activity concentration in water on radon activity in the air inside the spa was observed. It was found to increase indoor radon with increasing radon in the waters. Correlation with indoor radon and radon in water was more significant for baths and less significant for pool waters. In the cases filling of the bath from water taps, significantly contribute to the increased radon was observed in the pool and bath areas of the spa.

3

Distribution of indoor radon concentrations between selected Hungarian thermal baths

Shahrokhi A., Nagy E., Csordás A., Somlai J., Kovács T.

Nukleonika

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2016

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Vol. 61, No. 3

333--336

EN

Owing to the high potential of radon to increase the risk of lung cancer, health organizations are enforced to update their regulations and recommendations regarding indoor radon levels each year. In this study, the indoor radon concentrations of three randomly selected thermal baths in Hungary using CR-39 and an AlphaGUARD radon monitor were measured with regard to the new updated standards of the European Basic Safety Standard (EU BSS, Council Directive 2013/59/Euratom, 2014). The annual average of indoor radon concentrations in Parad Medical Bath, Igal Health Spa and Eger Turkish Bath were measured as 159 ± 19, 176 ± 27 and 301 ± 30 Bq/m3, respectively. Indoor radon concentration in all measurement locations were determined to be below the reference level, with the exception of the main pool, small pool and sparkling bath areas in the Eger Turkish Bath that were measured as 403 ± 42, 315 ± 32 and 354 ± 36 Bq/m3, respectively. In light of the results, the estimated annual average radon concentration in the thermal baths was below the EU BSS reference level of 300 Bq/m3. Personal dosimetry is required to estimate the annual effective dose from inhaled radon by the workers at the Eger Turkish Bath. This procedure is required in order to justify the application of the mitigation process of decreasing working hours, improving the ventilation rate or increasing the number of classified employees in response to the official radiation surveillance programme.

4

Investigation Of Intermetallic Compounds In Sn-Cu-Ni Lead-Free Solders

Nagy E., Kristaly F., Gyenes A., Gacsi Z.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1511--1515

EN

Interfacial intermetallic compounds (IMC) play an important role in Sn-Cu lead-free soldering. The size and morphology of the intermetallic compounds formed between the lead-free solder and the Cu substrate have a significant effect on the mechanical strength of the solder joint. In the soldering process of Sn-Cu alloys, Cu6Sn5 intermetallic compounds are formed. The complex structural behaviour of Cu6Sn5 IMC is temperature- and composition-dependent and it is long since subject to scientific research. The Cu6Sn5 phase basically exists in two crystal structures: hexagonal η-Cu6Sn5 (at temperatures above 186°C) and monoclinic η’-Cu6Sn5 (at lower temperatures). In the presence of Ni in the solder, the η-η’ transformation does not occur, therefore, the η-Cu6Sn5 phase remains stable. In this study the role of Ni in the (Cu,Ni)6Sn5 intermetallic compound in Sn-Cu lead-free solders was examined. Sn-Cu alloys with different Cu content (0.5 to 1 mass%) were modified through Ni addition. The morphology of the intermetallic compounds of the modified Sn-Cu alloys was investigated by optical microscopy (OM) and scanning electron microscopy (SEM), the IMC phases were examined with X-ray diffraction method (XRD).

5

Skomputeryzowany system weryfikacji pracy przenośników taśmowych

Ladanyi G., Nagy E.

Mechanizacja i Automatyzacja Górnictwa

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2012

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R. 50, nr 11

37--45

PL

Przenośniki są ważnymi elementami systemów przenoszenia materiałów w wielu działach przemysłu, zwłaszcza w przemyśle wydobywczym. Energia elektryczna używana do napędzania przenośników taśmowych w kopalniach odkrywkowych jest istotnym elementem kosztów zakładu górniczego. Dlatego też każdy rodzaj oszczędności uzyskany w tym zakresie skutkuje znaczną i zauważalną obniżką stałych kosztów przedsiębiorstwa [2, 3, 4]. Aby oszczędzać energię elektryczną należy najpierw przeanalizować system napędowy, a następnie zidentyfikować punkty, w których możliwa jest oszczędność energii. Artykuł przedstawia model wspomaganego komputerowo systemu przenośnika taśmowego. Model pracuje z programem EXCEL. Wyniki uzyskane z analizy pracy programu mogą zostać użyte do wspomagania decyzji użytkowników przenośnika taśmowego. Model może być też wykorzystany do celów edukacyjnych.

EN

In many industries, conveyors are an important part of a material handling system especially in mining industries. Electric power that is used for driving belt conveyors of surface mines is a significant item among the costs of a mining plant [2, 3, 4]. Hence, every saving achieved in this area results in a major and remarkable reduction of the fixed costs for the company. To save electric power the best way is to first examine a driving system and identify the right point of energy saving. The paper deals with the presentation of features of a computer aided model of conveyor belt. The model was developed to run with EXCEL. The results obtained from program running can be used to help making a good decision for the users of conveyor belt. On the other hand it can be used in the education too.

6

Effect of variable diffusivity and solubility under different flow conditions on mass transfer in hollow fibres

Nagy E.

Zeszyty Naukowe. Inżynieria Środowiska / Politechnika Śląska

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2002

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z. 46

71-79

EN

The mixing-cup concentration for hollow-fiber membrane is investigated under different flow conditions (parabolic flow and plug flow) and at different concentration dependent diffusivity and solubility. The results show significant effect of flow conditions on the concentration in the hollow fiber. Similarly the variable diffusivity and solubility have significant influence on the process.

PL

Badano rozkłady stężenia z uwzględnieniem mikromieszania w modułach kapilarnych dla różnych warunków przepływu (laminamy i burzliwy) oraz przy różnych stężeniach zależnych od dyfuzyjności i rozpuszczalności. Wyniki pokazały znaczący wpływ warunków przepływowych na stężenie w modułach kapilarnych. Podobnie, zmienna dyfuzyjnośc i rozpuszczalność mają istotny wpływ na proces membranowy.