gradual increase of the earth's surface temperature can cause many significant changes on the climate of our planet. this problem is progressively increasing. one of the main reasons for this phenomenon is the absorption of the sun's energy and lack of proper reflection of emissions due to man-made activities, one of which is the increase in black surfaces. in this descriptive and cross-section...

background and objectives: hospital surfaces can serve as reservoirs of potential pathogenic bacteria.staff hands are the main source of bacterial transmission in hospital. the prevalence of bacteria harboring β– lactamase enzyme in staff hands and hospital surfaces, leads to spread of β–lactamase producing bacteria and ultimate increase of antibiotic resistance nosocomial infections. the aim o...

despite of suitable geological and climatic conditions for forming and evolution of alluvial fans and importance of this landform as soil and water resources in arid regions, there are limited studies about this landform in iran. in the present study, evolution and pedogenic development of geomorphic surfaces of an alluvial fan in eastern isfahan were studied by using remote sensing, field and ...

A practical application of the spherical involute surface to the forged straight bevel gears is provided and demonstrated in this work. Conjugate (pure involute) theoretical surfaces are developed from the input design parameters. The surfaces are modified to suit the actual application (automotive differential). The unloaded (or low load) tooth contact analysis of modified surfaces is performe...

Background and Objectives: Investigating the risk factors in osteoporosis elderly to prevent falls and fractures is of high importance. Therefore, this study assesses the effect of different surfaces on postural stability and gait variations in the osteoporosis elderly. Methods: 22 elderlies participated (11 with severe osteoporosis & 11 healthy elderly) in this study in two static and dynam...

In this paper, we define X-slant helix in Euclidean 3-space and we obtain helix, slant helix, clad and g-clad helix as special case of the X-slant helix. Then we study Darboux, tangential darboux developable surfaces and their singular points. Especially we show that the striction lines of these surfaces are singular locus of the surfaces.

In this paper, we show that an $L_1$-2-type surface in the three-dimensional hyperbolic space $H^3subset R^4_1$ either is an open piece of a standard Riemannian product $ H^1(-sqrt{1+r^2})times S^{1}(r)$, or it has non constant mean curvature, non constant Gaussian curvature, and non constant principal curvatures.

In this paper a Frequency Selective Surface (FSS) as a UWB electromagnetic shield is introduced. The proposed FSS comprises a quasi-J.C-Jerusalem Cross- and a copper ring, which are located at both sides of a FR4 substrate and can represent a S.E -Shielding Effectiveness- better than 20dB in 90% bandwidth of Ultra Wide Band frequency. This structure is compact and thin. Each cell comprises J.C ...

an investigation was made to study the residual activity and air- borne effect of pirimiphos- methyl, at 2g a.i./m2 in hut scale trials on different surfaces in kazeroun, and bandar-abbas, south of iran. in kazeroun area, bio-assay contact mortality test with pirimiphos methyl on mud, wood, cement and plaster surfaces, 54 days after hut spraying, decreased from 100% to 46.7%, 61.25%, 36.6% and ...