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Dzurenda L.,Technical University In Zvolen
Wood Research | Year: 2013

By a process of thermal treatment using water steam, the colour of beech wood changes from light white-yellow with a yellow tint through brown-pink to dark red-brown shade depending on the conditions of the technological process. The goal of this paper is to determine the colour of beech wood in CIE-L a b colour space after thermal treatment - steaming using saturated water steam with temperature of t = 125-130°C for the duration of T = 6.5 h. The colour of surface of seasoned, thermally treated and milled beech wood blanks in CIE-L a b olour space is expressed by coordinates: L = 58.1 ± 3.8; a = 15.5 ± 2.2; b = 24.9 ± 1.3. Source

Kalincova D.,Technical University In Zvolen
Manufacturing Technology | Year: 2012

The paper is aimed at the analysis of a welded band-saw blade joint. The analysis is focused on the influence of joint annealing on the microstructure and mechanical properties. The results of experimental work are focused on an assessment of a set of band-saw blades samples made of material DIN C75. The samples have been welded and evaluated in the states prior and after welding and annealing. The purpose of the experiment was to analyse the influence of different annealing temperatures on structural and mechanical properties and based on the analysis to propose optimal heating temperature that guarantees reliable operation of the band-saw blades. The results of hardness measurement and microstructure evaluation confirmed the need of annealing after welding of band-saw blades. Source

Sujova E.,Technical University In Zvolen
Engineering Review | Year: 2012

Utilization of metalworking fluids in the technological process of metalworking brings its advantages and disadvantages, mainly associated with the contamination of the working air through cutting fluid mist. The primary aim of this article is to approximate the mechanism of aerosols generation which contaminates the working air and to draw the attention to the problem of quantification of generated aerosols that are to be kept to exposure limits. The focus has been placed on the mechanisms of cutting fluid mist formation via atomization on a stationary or a rotating workpiece and on the other hand, via vaporization. The next objective is to characterize health risks resulting from the utilization of metalworking fluids in the production process. Source

Hricova J.,Technical University In Zvolen
Manufacturing Technology | Year: 2013

Milling is one of the most universal operations in machining processes because it can remove the redundant part of material efficiently, and moreover, it can produce almost all kinds of contour surfaces with a high quality finish. Surface roughness plays an important role in determining the product quality since it strongly influences the performance of mechanical parts as well as production cost. Many types of cutting materials are used as tool materials in today's metalworking industry. Selecting the proper cutting tool material for a specific machining applicationcan provide substantial advantages including increased productivity, improved quality and ultimately reduced costs. This article is aimed at determining the influence of different tool materials on surface roughness of AlMgSi aluminium alloy after side milling with using of the analysis of variance (ANOVA). © 2013 Published by Manufacturing Technology. Source

Biomass is one of the most effective renewable energy sources, with highest potential for future. Poplars are widely used to produce biomass for energy. This article presents the methodology and results of experimental testing of the calorific value and ash content of the wood-chips produced from Populus x euroamericana clone MAX 4. Monitoring of dendrometric wood properties was carried out on 1 144 individuals, and to assess the production can be stated as follows: the average taking of the monitored area was 95.9%, the thickness strain in the middle d1,3 is 7.8 mm and an average height is 1.48 m. The relative Poplar wood moisture was wr = 59.19 %, and of bark wr = 52.29 %. The gross calorific value of wood and bark of the clone MAX 4 was assessed through an experimental measurement in a calorimeter for solid fuels, model IKA C 200. Net calorific value of wood and bark were calculated from the gross calorific value qv,gr,d, as well as the hydrogen [w(H)d] and relative moisture [MT] in the wood-chips. The gross calorific value and net calorific value of wood was qv,gr,d = 19 882 kJ·kg−1, qv,net,m = 8 345 kJ·kg−1. The gross calorific value and net calorific value of bark was also assessed qv,gr,d = 20 372 kJ·kg−1, and qv,net,m = 9 607 kJ·kg−1. The share of bark in the wood-chips was assessed 32.7 %. Ash content of wood was assessed Ad = 1.3 % and of bark Ad = 4.0 %. Observed values have been determined for one-year-old poplar cuttings and they are higher than the chips at the end of the production period for about 4 years. © 2015, Technical University in Zvolen. All rights reserved. Source

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