in the present study the effect of curvature ratio and coil pitch for tio2/water nanofluid laminar flow on heat transfer behavior and pressure drop through helical coils with different geometries was investigated experimentally. the tio2/water nanofluids at 0.25% to 2% particle volume concentrations have been prepared by using a two-step method. the experiments were performed for coils with cur...

PURPOSE To evaluate the physical characteristics and behavior of coils for endovascular therapy. METHODS Mechanically detachable coils were constructed with simple helical (4 mm X 10 cm and 8 mm X 30 cm) and pretzel shapes (4 mm X 5 cm) made from three metals using 0.003- and 0.004-in wire. Stiffness or pliability, frictional resistance, shape memory, and coil stability were evaluated in vitr...

Nine embolization experiments of a silicone aneurysm model were conducted by using helical and complex-shaped coils. Coils were introduced up to the point when the adjunct of a supplementary coil caused protrusion into the parent vessel. Packing ratios (volume of coils-aneurysm volume) ranged between 31% and 38%. Optimal packing was achieved with complex-shaped coils used in a concentric fashio...

Our clinical experience with interlocking detachable coils for the embolization of high-flow dural arteriovenous fistulas is reported. Interlocking detachable coils are useful for transarterial and transvenous embolizations of dural arteriovenous fistulas because (a) immediate coil detachment is possible, (b) the coils can be replaced easily, (c) detached coils rarely migrate, and (d) fewer int...

the star-mesh transformation allows the reduction of nodes in an electrical circuit. the gauss elimination method allows the reduction of unknowns in a system of linear equations . triangular decomposition can be used to find the inverse of a matrix. in this paper the coherence between these methods are discussed. it is shown that the gauss elimination method gives the same formula for star-mes...

introduction the aim of this study was to compare the characteristics of deflection load of three kinds of nickel titanium closed coil springs. methods and materials this research was an experimental study. research sample contains three kinds of niti closed coiled springs (heavy, medium, light) from gac, 3m, and rmo factories. 10 springs with 9 mm length for each group (totally 90 springs) wer...