نتایج جستجو برای: resin composites statement of problem
تعداد نتایج: 21228781 فیلتر نتایج به سال:
In this paper the effect of hardener on mechanical properties of carbon reinforced phenolic resin composites is investigated. Carbon fibre is one of the most useful reinforcement materials in composites, its major use being the manufacture of components in the aerospace, automotive, and leisure industries. In this study, carbon fibres are hot pressed with phenolic resin with various percentages...
Statement of Problem: Recently, investigators have presented new methods to reduce polymerization shrinkage of composite resin restorations. It is claimed that more powerful light cure systems associated with a change in radiation patterns, lead to improved mechanical properties and reduced microleakage. Purpose: The aim of the present study was to evaluate the effects of two curing systems, kn...
STATEMENT OF PROBLEM Some clinical situations may require the repair of a secondary polymerized or aged composite. The higher indirect resin conversion rate may prove to be a disadvantage if a repair procedure based on covalent bonding from unreacted methacrylate groups is attempted. PURPOSE This study evaluated the effectiveness of different combinations of surface treatments and 2 bonding a...
determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...
STATEMENT OF PROBLEM Dental resin composites are becoming prevalent in restorative dentistry and have almost replaced amalgam nowadays. Consequently, their mechanical properties and durability are critical. OBJECTIVES The aim of this study was to produce Pyrex glass nano-particles by wet milling process and use them as reinforcement in dental resins for anterior restorations and then examinat...
heuristics are often used to provide solutions for flow shop scheduling problems.the performance of a heuristic is usually judged by comparing solutions and run times on test cases.this investigation proposes an analytical alternative ,called asymptotic convergence ,which tests the convergence of the heuristic to a lower bound as problem size grows. the test is a stronger variation of worst cas...
In this study three types of Fibre reinforced composites Glassfibre/epoxy, Glassfibre/vinylester and Glassfibre/polyester resin are fabricated using Hand lay-up process and compacted in a Hotpress. The specimens of these three types of laminates were studied for moisture diffusion at two elevated hotwater temperatures of 90C and 60C to study the kinetics by computing the Diffusion coefficients ...
STATEMENT OF THE PROBLEM The bond strength of composites with different adhesive systems with dentin is an important factor in long term durability of composite restorations. The effect of titanium tetrafluoride (TiF4) as anti caries agent and sodium hypochlorite (NaOCl) as disinfectant on the shear bond of nanofilled and silorane based composite resins have not been investigated in previous st...
Background and Aims: The aim of this study was to evaluate the effects of two fluoride containing mouth rinses on the color stability of two different resin composites. Materials and Methods: 27 specimens (2×4×5 mm) were prepared from each of the following materials: a micro filled composite (Gradia, GC) and nanohybrid (Grandio). The specimens were polished by Soflex fine and super...
OBJECTIVES To evaluate the regional mechanical properties of dual-cure resin composites and their regional bond strengths to root canal dentin. METHODS One of the following dual-cure resin composites was placed in artificial post spaces: Unifil Core (UC), Clearfil DC Core (DC), Build-It FR (BI), Clearfil DC Core-automix (DCA), and photo-cured for 60s. After 24h storage, each specimen was seri...
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