Statistical Modeling of Pin Gauge Dimensions of Root of Gas Turbine Blade in Creep Feed Grinding Process
Creep feed grinding is a recently invented process of material handling. It combines high quality of the piece surface, productivity, and the possibility of automatic control. The main objectives of this research is to study the influences of major process parameters and their interactions of creep feed grinding process such as wheel speed, workpiece speed, grinding depth, and dresser speed on the pin gauge dimensions of root of gas turbine blade by design of experiments (DOE). Experimental results are analyzed by analysis of variance (ANOVA) and empirical models of pin gauge dimensions of root are developed. The study found that higher wheel speed along with slower workpiece speed, lower grinding depth and higher dresser speed, cause to obtain best conditions for pin gauge dimensions of root.
Analysis of Workpiece Temperature and Grinding Burn in Creep Feed Grinding
This paper aims to clarify workpiece temperature and the mechanism of grinding burn in creep feed grinding. The workpiece is modelled thermally by a three dimensional finite element method. The cooling effect of coolant is measured and the fraction of mechanical energy conducted as heat into the workpiece is estimated by Jaeger's moving heat theory extended to include the cooling effect. The analytical results are shown to agree well with the experimentally obtained temperature distribution. From the experimental evidence that the onset of grinding burn is closely related to the boiling of the coolant used, the mechanism of the grinding burn can be considered as follows; when the grinding zone temperature reaches a point at which bubbles begin to form, the bubbles grow up rapidly in the wheel-workpiece interface and block heat transfer to the coolant. This is verified by the above-mentioned thermal mode.
The Italian Renaissance: Culture and Society in Italy
In this newly revised edition of his widely acclaimed work, Peter Burke presents a social and cultural history of the Italian Renaissance. He discusses the social and political institutions that existed in Italy during the fifteenth and sixteenth centuries, and he analyzes the ways of thinking and seeing that characterized this period of extraordinary artistic creativity. Developing a distinctive approach, the author is concerned not only with the finished works of Michelangelo, Raphael, Leonardo da Vinci, and others, but also with the social background, patterns of recruitment, and means of subsistence of this "cultural elite." He thus makes a major contribution both to our understanding of the Italian Renaissance and to our comprehension of the complex relations between culture and society. An excellent social history of the lives and culture of the artists and artisans which made it possible for the arts to flourish.