STATISTICAL APPROACH FOR MULTI CRITERIA OPTIMIZATION OF CUTTING PARAMETERS OF TURNING ON HEAT TREATED BERYLLIUM COPPER ALLOY

In machining operations, achieving desired performance features of the machined product, is really a challenging job. Because, these quality features are highly correlated and are expected to be influenced directly or indirectly by the direct effect of process parameters or their interactive effects. This paper presents effective method and to determine optimal machining parameters in a turning operation on heat treated Beryllium copper alloy to minimize the surface roughness, cutting forces and work tool interface temperature along with the maximization of metal removal rate. The scope of this work is extended to Multi Objective Optimization. Response Surface Methodology is opted for preparing the design matrix, generating ANOVA, and optimization. A powerful model would be obtained with high accuracy to analyse the effect of each parameter on the output. The input parameters considered in this work are cutting speed, feed, depth of cut, work material (Annealed and Hardened) and tool material (CBN and HSS)

Comparison of panoramic radiograph with cone-beam computed tomography in assessment of maxillary sinus floor and nasal floor

Introduction: Panoramic radiograph is frequently prescribed by dentists for implant planning and, hence, accurate assessment of anatomical structures in panoramic radiograph is of utmost importance. Aims: The aim of the present study is to know the accuracy of panoramic radiograph in assessment of relationship between maxillary sinus floor and posterior teeth roots, and the distance from alveolar crest to nasal floor by comparing it with that of cone-beam computed tomographic (CBCT) image. Materials and Methods: Panoramic and CBCT images of 30 patients were analyzed. The topographic relationship of each root of posterior teeth to the maxillary sinus floor was evaluated and classified into three classes. The distance from the peak point on maxillary alveolar crest to nasal floor was measured in panoramic radiograph as well as in CBCT image. All the measurements were made by built-in measurement tools. Results: Class 1 roots in panoramic radiograph showed high agreement (86%) with CBCT image, followed by class 0 (76%). There was a significant difference in the measurements of alveolar bone height (ABH) in the nasal floor region with a P value of 0.018. Conclusion: Panoramic radiograph is reliable in assessment of nasal floor and maxillary sinus, provided position of the patient, distortion, and the inherent magnification factor are taken into consideration

Reliability of single panoramic radiograph with vertical and horizontal parallax; and intraoral periapical radiograph with Clark′s rule compared to computed tomography/surgical exposure in localization of impacted permanent maxillary canine

Aim: The aim of the study was to evaluate an accurate, inexpensive and low-radiation conventional radiograph suitable for localization of impacted maxillary permanent canine. Materials and Methods: The study comprised 38 subjects in the age group of 13-50 years of both the genders with 50 impacted canines. Panoramic radiographs (OPGs) (on which Chaushu et al. criteria was applied) and intraoral periapical radiographs (IOPARs) (on which Clark′s rule was applied) of the subjects were made and the accuracy of the above two radiographic techniques were compared with computed tomography (CT) axial sections or with surgical exposure, which was considered as the standard guide for localization of impacted maxillary permanent canine. The data obtained was tabulated and subjected to statistical analysis using the statistical package for SAS software. Results: Localization of impacted maxillary permanent canine tooth done with SLOB (Same Lingual Opposite Buccal)/Clark′s rule technique could predict the bucco-palatal canine impactions in 98% of cases. OPG using differential magnification index could predict location only in 68% of bucco-palatal canine impactions and in 72% based on vertical position. Conclusion: In 68% of cases the bucco-lingual position of the canine in OPG (by magnification index) coincided with the location as per CT/surgical exposure. In 98% of cases localization with SLOB technique coincided with CT/surgical exposure. 72% of cases showed coincidence with vertical position of the canine on OPG with CT/surgical exposure. IOPARs taken with SLOB technique are more accurate than OPGs for localization of impacted permanent maxillary canine teeth