Plant cuticles are covered by epicuticular waxes with considerable ultrastructural and chemical diversity and have great systematic significance. Pinus elderica is a rare pine found naturally only in desert environment southeast of Tbilisi (Georgia). This tree have been probably introduced to Iran about 800 years ago and gradually altered in both shape and size in Nashtifan-Khaf, and changed in...

a finite element analysis is presented for sloshing and impulsive motion of liquid-filled conical tanks during lateral anti-symmetric excitation. the performed analyses led to the development of a number of charts which can be used to identify the natural frequency, the mode shapes of conical tanks for both fundamental and the cos(θ)-modes of vibration. conical tank geometry was described with ...

A finite element analysis is presented for sloshing and impulsive motion of liquid-filled conical tanks during lateral anti-symmetric excitation. The performed analyses led to the development of a number of charts which can be used to identify the natural frequency, the mode shapes of conical tanks for both fundamental and the cos(θ)-modes of vibration. Conical tank geometry was described with ...

the researches have made different explanations about rhytons, but they mostly accepted that “rhyton is a kind of a drinking vessel often in the form of an animal, having two holes for pouring water.” rhytons were used in iran from forth millennium b.c. to the end of sasanian period. the animals that are used are of two different kinds: imaginary animals or the real animals. diversity of the sh...

poor stand establishment of canola (brassica napus l.) under flatland mechanized planting and crust-forming soil is a major problem for farmers in central iran. previous research there showed that irrigated cotton emergence on crust-forming soils under flatland planting can be significantly improved using a double-disk planter with zero-pressure press wheel tires and no crust-breaking. in that ...

In this paper, crashworthiness characteristics of conical steel tubes stiffened by annular rings and rigid polyurethane foam are investigated. For this purpose, wide circumferential rings are created from the outer surface of the conical tube at some determined areas along tube length. In fact, this method divides a long conical tube into several tubes of shorter length. When this structure is ...

Water transport through aquaporin water channels occurs extensively in cell membranes. Hourglass-shaped (biconical) pores resemble the geometry of these aquaporin channels and therefore attract much research attention. We assumed that hourglass-shaped nanopores are capable of high water permeation like biological aquaporins. In order to prove the assumption, we investigated nanoscale water tran...

We stdy the spectral reflectivity of conical-, cylindricaland parabolic-shaped silicon nitride (Si3N4) sub-wavelength structures (SWS). A multilayer rigorous coupled-wave approach is adopted to estimate the reflection properties of Si3N4 SWS. Optimal shapes of SWS in terms of effective reflectance are analyzed over a range of wavelength. The results of our study show that a 3.15% effective refl...

An ultra-wideband (UWB) self-complementary planar bow-tie antenna (SCPBTA) is proposed. The antenna consists of a printed conical horn-shaped (CHS) radiator and a counterpart CHS slot etched on a rectangular ground plane. The printed CHS radiator is connected directly to the 50Ω microstrip line by bending the end portion of the feed line. As a result, the antenna has a simple structure which do...

Combine harvesters are widely used worldwide in harvesting many crops, and they have functions that cover the entire process, such as cutting, threshing, separating, cleaning. The threshing drum is core working device of combine harvester plays an influential role rice efficiency, power requirement, seed loss. In this study, two structures threshers (conical-shaped cylindrical-shaped) were test...