one of the difficulties in using absolute altitudes is the separation between the mean open sealevel and geoid. theoretically, geoid is the base level in absolute altitudes, but practically, the mean open sealevel is used as a base level for absolute altitudes. the difference between these two levels is called as the seasurface topography. in this research, it is dealt the mean sea level modeli...

abstract background and aim: one of the major problems with resin composite restorations is the weakness of bonding between the new and aged composites. since appropriate micromechanical retention is necessary for the repair of aged resin composite restorations, the level of surface roughness after sandblasting can be influential in this regard. considering the diverse composition of available ...

microstructural evolutions of twinning induced plasticity (twip) steel during tensile straining wereinvestigated by in situ sem observations. the results indicated that slip lines and mechanical twins aswell as surface relief were increased with increasing strain, resulting in a stepped surface. additionally,these deformation mechanisms could change the shape of each grain via shear and rotatio...

there are dierent ways to code the geodesic flows on surfaces with negative curvature. such code spaces give a useful tool to verify the dynamical properties of geodesic flows. here we consider special subspaces of geodesic flows on hecke surface whose arithmetic codings varies on a set with in nite alphabet. then we will compare the topological complexity of them by computing their topologica...

zinc oxide (zno) nanoparticles were synthesized by spray pyrolysis method using an aqueous solution of zinc acetate at various concentrations from 5 to 25 wt%. the decomposition of precursor solutions was carried out at 800, 1000 and 1200ºc under different atomizing pressures. the crystal structure and morphology of synthesized nanoparticles were characterized by x-ray diffraction (xrd) spectro...

since heavy metals are considered as one of the major pollutants threatening, the main goal of this study was to bring out the concentrations of pb, zn and mn in the surface sediments off bushehr in the persian gulf. for this purpose, after collection of samples, the concentrations of the three metals in surface sediments were measured through the atomic absorption. the results were compared wi...

free surface modeling plays an important role in some ocean structures design, especially in oscillating water column (owc) devices. boundary element method (bem) is a suitable method for free surface modeling due to its simplicity, quick solving, and low data storage requirement. in this paper, bem was used for free surface modeling in owc chamber and out of it. linear kinematic and dynamic bo...

in this paper, the lorentzian version of beltrami-euler formula is investigated in 1n . initially,the first fundamental form and the metric coefficients of generalized timelike ruled surface are calculated and by the help of the christoffel symbols, riemann-christoffel curvatures are obtained. thus, the curvatures of spacelike and timelike tangential sections of generalized timelike ruled surf...

the levels of 19 organochlorine pesticides (ocps) in surface water and under water sedimentsfrom tanks located nearby the prime agricultural areas of kanyakumari district, tamil nadu, india wereinvestigated to evaluate their pollution risks. a total of 36 surface water samples at 9 sampling sites and27 sediment samples at 9 sampling stations were collected from tanks, which were the water sourc...

when thinking about traditional iranian architecture, one imagines extensive ornamental patterns that adorn almost every surface of mosques and other prominent buildings. yet, many theories of architecture since the beginning of twentieth century have considered ornamentation a superficial and superfluous layer. but, are these ornamental surfaces superficial and can they be removed so easily? t...