This paper describes an ultra precision polishing method of aspherical mirrors, and the fundamental research on polishing characteristics. The aspherical mirrors with a diameter of about 30mm made by fused silica glass and CVD-SiC were ELID (electrolytic in-process dressing)-ground to high form accuracy with #4000 cast iron bonded diamond wheel, and then polished with a small polishing tool. As...

For time and cost saving reasons, the lowest surface roughness possible is sought in milling operations. High speed milling is recommended in order to minimise the amount of material to be removed in subsequent finishing operations, e.g. grinding, electrical discharge machining or manual polishing. Several roughness parameters are usually employed for the characterization of polished surfaces. ...

UNLABELLED Esthetics and durability of materials used to fabricate artificial eyes has been an important issue since artificial eyes are essential to restore esthetics and function, protect the remaining tissues and help with patients' psychological therapy. However, these materials are submitted to degrading effects of environmental agents on the physical properties of the acrylic resin. OBJ...

The widespread use of aesthetic f illings has highlighted their advantages and disadvantages. One of the most troublesome features of earlier aesthetic materials was the difficulty of finishing the restoration surface to decrease adherence of food debris. The rougher the finished surface, the greater the possibility of bacterial accumulation and discolouration of restoration along the restorati...

Polishing can be more uniform if the polishing path provides uniform coverage of the surface. It is known that Peano paths can provide uniform coverage of planar surfaces. Peano paths also contain short path segments and turns: (1) all path segments have the same length, (2) path segments are mutually orthogonal at the turns, and (3) path segments and turns are uniformity distributed over the d...

The mortality pattern among 86 men was determined to investigate the possible hazards of polishing steel. The men had polished steel with polishing paste for at least five years. The polishing pastes had contained tallow, beeswax, carnauba wax, alundum, carborundum, ferric oxide, and chalk. A total of 18 men had died compared with 13.3 expected. Four had died of stomach cancer compared with 0.4...

The hardened microstructure of 5 wt.% Cr cold work tool steels is mainly martensitic with significant amount retained austenite and some undissolved carbides. Whereas the after tempering shows amounts angular shaped blocky regions, which are interpretated as or fresh martensite. distinction between phases difficult due to morphological similarities. Therefore, regions characterized by electron ...

The present study proposes novel micro-jet impingement heat sink with effusion holes for flow extraction. The design consists of impingement nozzles surrounded by multiple effusion holes to take away the spent fluid. A three-dimensional numerical model is used for steady, incompressible, laminar flow and conjugate heat transfer for the performance analysis of the proposed design. The computatio...

In this study, scaling, polishing and daily tooth brushing were performed in 20 beagle dogs, and the number of oral bacteria was determined using a bacterial counter. The dogs were randomized into the scaling (S), scaling + polishing (SP), scaling + tooth daily brushing (SB) and scaling + polishing + tooth daily brushing (SPB) groups. Samples were collected from the buccal surface of the maxill...