composite pressure vessel cng made of epoxy – carbon material with nonmetal liner is 60% lighter than aluminum vessel under the same conditions. one of the important parameters in the pressure vessels design is their resistance against impact and prevention of explosion. in this paper, the effects of low velocity impact on composite pressure vessel are investigated using fe analysis. the vessel...

to evaluate the ultimate compressive strength of five composite resins after 1 hour, 24 hours, 7 days and 1 month. twenty four cylindrical 4 mm×8mm specimens of each commonly used composite resins in posterior region (nulite-f , z250 , p60, biscore, tetric ceram hb) were prepared. each group of composite resins were divided into four time groups of 1 h, 24 h, 7 days and 1 month. all of specimen...

Even though composite fermions in the fractional quantum Hall liquid are well established, it is not yet known up to what energies they remain intact. We probe the high-energy spectrum of the 1/3 liquid directly by resonant inelastic light scattering, and report the observation of a large number of new collective modes. Supported by our theoretical calculations, we associate these with transiti...

BACKGROUND In daily clinical practice, esthetics of anterior teeth is a common presenting complaint of patients. OBJECTIVE This case report discusses the management of asymmetric smile associated with unsatisfactory extensive composite restorations and describes a clinical protocol using the direct composite resin for smile enhancement to restore the dental harmony of anterior teeth. METHOD...

A nonlinear microwave phase shifter based on ferrite-ferroelectric composite material has been studied for the first time. The ferrite-ferroelectric composite is fabricated in the form of bilayer consisted of yttrium iron garnet and barium strontium titanate. A principle of operation of the device is based on the linear and nonlinear control of the phase shift of the hybrid spinelectromagnetic ...

Esthetic or cosmetic dentistry is one of the main areas of dental practice. Increasing demand of patients for esthetics has resulted in the development of several techniques for restoring the anterior teeth. Composite resin restorations have become an integral part of contemporary restorative dentistry and can be called "star of minimal invasion" due to its conservative concepts. The direct com...

The notion of $f$-derivations of UP-algebras is introduced, some useful examples are discussed, and related properties are investigated. Moreover, we show that the fixed set and the kernel of $f$-derivations are UP-subalgebras of UP-algebras,and also give examples to show that the two sets are not UP-ideals of UP-algebras in general.

background: esthetic demands among patients have led to the introduction of tooth-colored restorations. composite resins bond to enamel applying acid etch technique. total etch adhesion systems are still considered as golden standard among bonding systems. however, clinicians have tendency towards using adhesive systems with a simplified application procedure. the aim of the present study is to...

objective : application of sodium ascorbate as an antioxidant and calcium hydroxide as a buffering agent following intracoronal bleaching has been recommended. the aim of this study was to investigate the effect of using the mentioned materials on shear bond strength of composite resin to the bleached dentin. materials and methods: in this in vitro investigation, sixty human sound premolars wer...

objective: the aim of this in vitrostudy was to evaluate the effect of the type of solvent in silane solution on microtensile bond strength of fiber posts to composite resin cores af-ter application of 24% hydrogen peroxide. materials and methods: eighteen white fiber posts, immersed in 24% hydrogen peroxide were divided into three groups (n=6). in the group a post surfaces were silanized with ...