tan films with different n2 partial pressure were deposited on 304 stainless steel using the magnetron sputtering method. the effect of gas pressure on the mechanical property, morphology and phase structure of the films is investigated by x-ray diffraction (xrd), atomic force microscopy (afm), microhardness testing, friction coefficient measurements, and wear mechanism study. the xrd results c...

OBJECTIVE The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). MATERIALS AND METHODS From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bot...

The present experimental investigations deal with the improvement of mechanical properties of cold work tool steels through different heat treatment processes. An attempt was made to get optimal combination of hardness and toughness through changes of microstructure by heat treatment. The toughness of D2 tool steel increases with tempering temperature. The hardness of D2 tool steel decreases wi...

the formation of renal and urinary calculi is not due to a single cause but occurs as a multifactor entity, by which some of them still are unknown. three theories of stones formation including nucleation, stone matrix and inhibition of crystallization do not accuse water hardness as a main cause of the formation of urinary calculi 120 patients suffering from renal and urinary calculi and the s...

in order to prevent water losses through disposing hydrous sludge during treatment of water, also recovery and reuse of chemicals; treatment by magnesium carbonate as a coagulant was examined in batch and continuous systems. 600 mg/1 mgco3 as optimum dosage reduced 80% turbidity of a highly turbid water containing 200 ntu. sulfates decreased, but hardness and alkalinity showed some increases. r...

optimum concentration of vitamin c and hardness at giant freshwater prawn brood-stock tank water has great important on their reproductive quality in recirculation system. the main objective of the present study is investigation on effects of different concentrations of these factors on reproductive parameters of the giant freshwater prawn female brood-stock. for this purpose, at the first expe...

PURPOSE To evaluate the depth of cure and surface hardness of two resin composites when subjected to three preheating temperatures, three polymerization times and two types of curing lights. METHODS Two resin composites were used in this study (Esthet-X and TPH), three polymerization times (10, 20, 40 seconds), three preheating temperatures (70, 100, 140 degrees F/21.1, 37.7 and 60 degrees C)...

PURPOSE The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables), Silux Plus (microfilled) and Z100 (minifilled) before and after polishing at different times. MATERIALS AND METHODS For this purpose, 240 specimens (5mm diameter, 1.4mm high) were prepared. Vickers hardness was determined before and after...

INTRODUCTION We aimed to compare apical canal transportation of extracted teeth and two types of simulated resin blocks. MATERIALS AND METHODS Mesiobuccal root of extracted maxillary molars, high hardness simulated resin blocks (Knoop hardness=40) and low hardness simulated resin blocks (Knoop hardness=22) were prepared with K-files using step-back technique (n=15 canals in each group). Doubl...