in this paper, penetration of high velocity impact of 4340 steel and tungsten carbide projectiles with specific shapes in to ceramic armor that includes 10 mm alumina (95%) is considered analytically and simulated with ls-dyna software. bernoulli equation used to consider the penetration velocity in ceramics, shows that the penetration is better and easier by increasing projectile density. the ...

background: in megavoltage radiotherapy rooms, ordinary concrete is usually used due to its low construction costs, although higher density concrete are sometimes used, as well. the use of high-density concrete decreases the required thickness of the concrete barrier hence, its disadvantage is its high cost. in a nuclear reactor, neutron radiation is the most difficult to shield. a method for p...

the two-spotted spider mite, tetranychus urticae koch (acari: tetranychidae), is an economically important pest of ornamental plant in iran. the population abundance and spatial distribution were studied on five rosa cultivars including maroussia, wendela, elderado, wenedetta, and hot lady during two growing seasons of 2011 and 2012 in greenhouse. the k parameter, index of dispersion, lloyd’s m...

the ir and nmr spectra were coupled with quantum chemical calculations in dft approach usingthe hybrid b3lyp exchange-correlation functional to confirm the structure of 2-methoxycarbonyl-7-methyl-1,3-thiazino[3,2-b][1,2,4]triazine-4,8-dione 2d.

the present study aims at investigating the effect of different levels of lexical collocational density on efl learners’ reading comprehension. eighty sophomore students with different levels of proficiency studying at  zand institute of higher education in shiraz, iran were chosen from among eighty five learners based on their score distribution on a reduced toefl test constructed by education...

Flash sintering has been investigated as a modern sintering method through examining the effect of processing parameters such as current density, temperature, and contact paste on the flash sintered 8YSZ characteristic. 95% of theoretical density was achieved at 800°С in 30sec with a field intensity of 100V.cm-1 and a current density of 160mA.mm-2. Such relative density in conventional sinterin...

introduction: of the factors leading to false negative results in mammography is breast tissue density, and by increasing the density of breast tissue in mammography, the mammography sensitivity decreases. on the other hand, increasing the breast tissue density leads to increased risk of breast cancer. various factors such as inheritance, genetics, hormonal and reproductive factors, and nutriti...

in order to study the effect of chemical and biological fertilizers on silage corn under different plant densities, a split plot experiment was carried out in a randomized completely block design with three replicates in south western iran. the main plot included nitrogen fertilizer treatment at three levels (n1: with out chemical and organic fertilizers, n2: 75% chemical fertilizer + 100% orga...

background: osteoporosis is a major public health concern around the world. it has been shown that bone mineral den­sity is correlated to anthropometric measures like height and weight, but this association may vary depending on ethnic and environmental factors. the aim of this study was to identify probable relations between anthropometric measures and bone mineral density. methods: in this po...