نتایج جستجو برای: pitch to diameter ratios

تعداد نتایج: 10643411  

An experimental study is reported on natural convection heat transfer from a helical heating coil to the surrounding fluid. The coil is heated electrically and the surrounding fluid is selected to be water. The range of parameters are: Rayleigh number, 879 ?£ Ra ?£ 780168, Prandtl number, 4.22 ?£ Pr ?£ 10.02, dimensionless coil diameter,7.69 ?£ Dave /d ?£ 10.77, number of coil rings, 2 ?£ N ?£ ...

2008
Edmund R. Meyer John L. Bohn

We investigate whether storing baseballs in a controlled humidity environment significantly affects their aerodynamic properties. We measure the change in diameter and weight of baseballs as a function of relative humidity in which the balls are stored. The trajectories of pitched and batted baseballs are modeled to assess the difference between those stored at 30% relative humidity versus 50% ...

حمزه‌نژاد, رقیه , رسولی صدقیانی, میرحسن , مرادی, ندا ,

This study was conducted to investigate the effect of type and ratio of vermicompost on tomato growth, with five different types of vermicompost (platanus leaves, maple leaves, pruning apple trees and grape, waste of herbal extracts and azolla residues) and four ratios of vermicompost to peat and perlite (2:1 v/v) as 0, 1:3, 2:3 and 3:3, at greenhouse conditions. Results showed that type of ver...

Esmael FallahChoolabi Mehdi Ranjkesh Mojtaba Pourjafari

Nowadays the use of the Switched Reluctance Motors (SRMs) has been considerably increased in various home and industrial applications. Despite of many advantages of this type of motors, such as simple structure, low cost, and high reliability, the main disadvantage of them is the generation of high torque pulsation. This paper presents a novel method to optimize a typical SRM such that the torq...

, Nouri and A. M. Lavasani,

An experimental investigation on heat transfer coefficient is presented from three horizontal tubes in a vertical array in a duct for 500<ReD<6000. A mass transfer measuring technique based on psychrometry chart is used to determine heat transfer coefficient. The diameter of the tubes is 11 mm each spaced 40 mm apart and in-line pitch ratio varies &#10in the range 0.055<D/W<0.22. The experimen...

, Nouri and A. M. Lavasani,

An experimental investigation on heat transfer coefficient is presented from three horizontal tubes in a vertical array in a duct for 500<ReD<6000. A mass transfer measuring technique based on psychrometry chart is used to determine heat transfer coefficient. The diameter of the tubes is 11 mm each spaced 40 mm apart and in-line pitch ratio varies in the range 0.055<D/W<0.22. The experimenta...

2018
Ying Chen Xiaoyan Deng Xinying Shan Yubin Xing

Pulmonary embolism is a severe, potentially life-threatening condition. Inferior vena cava filters have been used to prevent recurrent pulmonary embolisms. However, the build-up of thrombosis in vena cava filters after deployment presents a severe problem to patients. Previous studies proposed that filters with helical flow are beneficial and capable of alleviating this problem. In this study, ...

Journal: :مهندسی عمران فردوسی 0
احمدرضا محبوبی کامران پناغی

the seismic analysis of structures in the past relied on the assumed soil desirable effects as the elongation of excitation period with higher damping. therefore, imposing earthquake loading at the foundation level fulfilling higher safety requirements was the common practice until occasional movement amplifications demanded more rigorous research. the goal of the current study is to scrutinize...

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