The aim of this study is to verify and assess the quality of lessons in traditional and electronic textbook on general standards of textbooks quality. The method of theoretical analysis and content analysis was used. For the purpose of analyzing the contents of the sample we took teaching unit Measures and measurement from two textbooks: the traditional and the electronic. The electronic textbook, which has been the subject of research, is of quality and meets the standards of textbook quality.
Abstract This paper defines mathematical models of value changes for surface roughness ( Ra , μm) and heat affected zone width ( HAZ , mm) during high-alloyed steel 1.4828 laser cutting using oxygen as an assistance gas. For the definition of appropriate mathematical models, multiple linear regression analysis is used, with four independent variables that were varied at five levels. Following parameters are varied: cutting speed ( V ), assist gas pressure ( p ), focus position ( fs ) and stand-off ( N d ). In comparison between the model and the experimental results, it can be concluded that the effects of specified parameters on cut quality, productivity and thus the legitimacy of this technology for cutting high-alloyed steels are well described by the obtained mathematical models.
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