نتایج جستجو برای: flow characteristics

تعداد نتایج: 1112208  

As a necessary component, regenerator plays an important role in the refrigeration performance of the pulse tube refrigerator. The objective of this research is to investigate the flow characteristics in a porous regenerator of the pulse tube refrigerators, subjected to oscillating flow. The hydrodynamic and thermal behavior of the regenerator is investigated by considering porous media approac...

The augment of heat transfer and fluid of buoyancy-driven flow of Fe3O4-Water nanofluid in a square cavity under the influence of an external magnetic field is studied numerically. Cold temperature is applied on the side (vertical) walls and high temperature is imposed on the bottom wall while the top wall is kept at thermally insulated. The governing non-dimensional differential equations are ...

2007
Richard T. Harrison Colin M. Mason

There is a substantial literature on the relationship between gender and access to finance. However, most studies have been concerned with access to debt finance. More recently, the focus of this research has broadened to examine women and venture capital. This article extends the focus further by examining the role of women in the business angel market, which is more important than the formal ...

2003
Virve Ollikainen Jukka Lahtonen

This paper presents an aggregate flow portrait of the Finnish labour market by gender. First we document the magnitude and evolution of worker flows in the Finnish labour market, also observing the gender differences within the flows. Second, we characterise the cyclical and dynamic properties of the flows and the implied dynamics of the stocks. We estimate models for the transitions to and fro...

and M. Ashrafizadeh, E. Shirani, M. Talebi,

In this study, turbulent flow around a tube bundle in non-orthogonal grid is simulated using the Large Eddy Simulation (LES) technique and parallelization of fully coupled Navier – Stokes (NS) equations. To model the small eddies, the Smagorinsky and a mixed model was used. This model represents the effect of dissipation and the grid-scale and subgrid-scale interactions. The fully coupled NS eq...

A. Zandi, M. Shams, S. Sohrabi,

Cavitation and turbulence in a diesel injector nozzle has a great effect on the development and primary breakup of spray. However, the mechanism of the cavitation flow inside the nozzle and its influence on spray characteristics have not been clearly known yet because of the internal nozzle flow complexities. In this paper, a comprehensive numerical simulation is carried out to study the intern...

2002
P. SINGH R. P. MAHAJAN G. E. MURTY A. R. AITKENHEAD

The differences in phonation between men and women are thought to occur from anatomical differences in the larynx. However, it is not known if there are any differences in cough dynamics between the sexes. We investigated this by asking 100 healthy, non-smoking adults (50 male) to perform a voluntary cough into a tussometer. Each volunteer coughed at four different lung volumes, ranging from to...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم ریاضی و مهندسی کامپیوتر 1392

heuristics are often used to provide solutions for flow shop scheduling problems.the performance of a heuristic is usually judged by comparing solutions and run times on test cases.this investigation proposes an analytical alternative ,called asymptotic convergence ,which tests the convergence of the heuristic to a lower bound as problem size grows. the test is a stronger variation of worst cas...

2003
David H. Cooper Bo René Madsen Jim Graham

Measurement of motion in transabdominal ultrasound sequences of the small bowel is hampered by the unstructured, textured appearance of the images. We investigate a method of measuring Optical Flow in the sequences, based on an analysis of the spatio-temporal frequency spectrum. The method requires no unrealistic assumptions about the distribution of energy in the frequency spectrum and extends...

2011
W. G. Berendsohn A. Güntsch N. Hoffmann A. Kohlbecker K. Luther A. Müller

One of the most serious bottlenecks in the scientific workflows of biodiversity sciences is the need to integrate data from different sources, software applications, and services for analysis, visualisation and publication. For more than a quarter of a century the TDWG Biodiversity Information Standards organisation has a central role in defining and promoting data standards and protocols suppo...

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