Parametric analysis and optimization of hard turning at different levels of hardness using wiper ceramic insert

Measurement ◽  
2020 ◽  
Vol 158 ◽  
pp. 107712
Author(s):  
K Venkata Subbaiah ◽  
Ch Raju ◽  
Ch Suresh
2019 ◽  
Vol 18 ◽  
pp. 445-454 ◽  
Author(s):  
K.Venkata Subbaiah ◽  
Ch. Raju ◽  
R. S.Pawade ◽  
Ch. Suresh

2019 ◽  
Vol 20 (1) ◽  
pp. 109 ◽  
Author(s):  
Hamdi Aouici ◽  
Mohamed Elbah ◽  
Asma Benkhelladi ◽  
Brahim Fnides ◽  
Lakhdar Boulanouar ◽  
...  

The hard turning process has an attracting interest in different industrial sectors for finishing operations of hard materials. However, it still presents disadvantages with respect to process capability and reliability. This paper describes a comparison of surface roughness, specific cutting force and flank wear between mixed ceramic CC650 (Al2O3 (70%) + TiC (30%)) and reinforced ceramic CC670 (Al2O3 (75%) + SiC (25%)) cutting tools when machining in dry hard turning of AISI 4140, treated at 52 HRC using the response surface methodology (RSM). A mathematical prediction model of the machining responses has been developed in terms of cutting speed, feed rate and cutting time parameters. Experimental observations show that the surface roughness obtained with the mixed ceramic insert significantly improved when compared with reinforced ceramic insert with a ratio of 1.44. In the same way, insert CC650 has better performance compared to reinforced ceramic inserts CC670, in terms of the specific cutting force and flank wear.


Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.


Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.


2006 ◽  
Vol 11 (4) ◽  
pp. 304-311 ◽  
Author(s):  
Lars-Göran Nilsson

This paper presents four domains of markers that have been found to predict later cognitive impairment and neurodegenerative disease. These four domains are (1) data patterns of memory performance, (2) cardiovascular factors, (3) genetic markers, and (4) brain activity. The critical features of each domain are illustrated with data from the longitudinal Betula Study on memory, aging, and health ( Nilsson et al., 1997 ; Nilsson et al., 2004 ). Up to now, early signs regarding these domains have been examined one by one and it has been found that they are associated with later cognitive impairment and neurodegenerative disease. However, it was also found that each marker accounts for only a very small part of the total variance, implying that single markers should not be used as predictors for cognitive decline or neurodegenerative disease. It is discussed whether modeling and simulations should be used as tools to combine markers at different levels to increase the amount of explained variance.


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