نتایج جستجو برای: geometric diameter

تعداد نتایج: 198912  

Mahmoud Hosseini Mehran S. Razzaghi, Nima Rahmani

This study aims to investigate the effects of geometric imperfections on buckling of thin cylindrical shells due to global shear. To this end, more than 320 finite element models of cylindrical shells with different diameter to thickness ratios were prepared. Random imperfections with different amplitudes were applied to numerical models. The results revealed that global buckling of cylindrical...

The purpose of this study is to design a three-stage axial compressor with identical pressure ratio which makes an adequate pressure ratio and efficiency in design point conditions with rotational velocity of 38000rpm and mass flow rate of 3.2kg/s. First of all, considering some restrictions such as Dehaller number more than 0.7 in all sections of the stator and the rotor, and relative Mach num...

Journal: :iranian journal of mathematical chemistry 2010
k. ch. das i. gutman b. furtula

the concept of geometric-arithmetic indices (ga) was put forward in chemical graph theoryvery recently. in spite of this, several works have already appeared dealing with these indices.in this paper we present lower and upper bounds on the second geometric-arithmetic index(ga2) and characterize the extremal graphs. moreover, we establish nordhaus-gaddum-typeresults for ga2.

Journal: :iranian journal of mathematical chemistry 2010
k. ch. das i. gutman b. furtula

continuing the work k. c. das, i. gutman, b. furtula, on second geometric-arithmetic indexof graphs, iran. j. math chem., 1(2) (2010) 17-28, in this paper we present lower and upperbounds on the third geometric-arithmetic index ga3 and characterize the extremal graphs.moreover, we give nordhaus-gaddum-type result for ga3.

Journal: :bulletin of the iranian mathematical society 2014
morteza jafarpour seyed shahin mousavi

‎in this paper first we define the morphism between geometric spaces in two different types‎. ‎we construct two categories of $uu$ and $l$ from geometric spaces then investigate some properties of the two categories‎, ‎for instance $uu$ is topological‎. ‎the relation between hypergroups and geometric spaces is studied‎. ‎by constructing the category $qh$ of $h_{v}$-groups we answer the question...

Journal: :مهندسی بیوسیستم ایران 0
سیدمهدی غائبی کارشناسی ارشد، دانشگاه تهران سیدرضا حسن بیگی بیدگلی دانشیار، دانشگاه تهران محمدحسین کیانمهر دانشیار، دانشگاه تهران

iran is believed to occupy the second place, following turkey, among the apricot producing countries in the world. iran is faced with problems in export of apricot due to little or non-observance of drying principals and inattention to world market requirements. the physical and mechanical properties of agricultural products are the most needed and important parameters for design and developmen...

Journal: :American journal of physiology. Heart and circulatory physiology 2005
Wolfgang A Goetz Emmanuel Lansac Hou-Sen Lim Patricia A Weber Carlos M G Duran

Left ventricular (LV) longitudinal and transverse geometric changes during isovolumic contraction and relaxation are still controversial. This confusion is compounded by traditional definitions of these phases of the cardiac cycle. High-resolution sonomicrometry studies might clarify these issues. Crystals were implanted in six sheep at the LV apex, fibrous trigones, lateral and posterior mitra...

Journal: :Nano letters 2008
Woong-Ki Hong Jung Inn Sohn Dae-Kue Hwang Soon-Shin Kwon Gunho Jo Sunghoon Song Seong-Min Kim Hang-Ju Ko Seong-Ju Park Mark E Welland Takhee Lee

Surface-architecture-controlled ZnO nanowires were grown using a vapor transport method on various ZnO buffer film coated c-plane sapphire substrates with or without Au catalysts. The ZnO nanowires that were grown showed two different types of geometric properties: corrugated ZnO nanowires having a relatively smaller diameter and a strong deep-level emission photoluminescence (PL) peak and smoo...

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