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Article
Publication date: 1 September 2002

Assunta Andreozzi, Oronzio Manca and Vincenzo Naso

Research on natural convection in open channels is very extensive due to its role in many engineering applications such as thermal control of electronic systems. In this paper, a…

491

Abstract

Research on natural convection in open channels is very extensive due to its role in many engineering applications such as thermal control of electronic systems. In this paper, a parametric analysis is carried out in order to add knowledge of heat transfer in air natural convection for a symmetrically heated vertical parallel plate channel with a central auxiliary heated or adiabatic plate. The two‐dimensional steady‐state problem is solved by means of the stream function–vorticity approach and the numerical solution is carried out by means of the control volume method. Results are obtained for both a heated and unheated auxiliary plate, for a Rayleigh number in the range 103–106, for a ratio of the auxiliary plate height to the channel plate height equal to 0, 0.5 and 1 and for a ratio of the channel length to the channel gap in the range 5–15. Correlations for maximum wall temperatures and average channel Nusselt numbers are proposed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 12 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 7 March 2016

Salvatore Cunsolo, Dominique Baillis, Nicola Bianco, Vincenzo Naso and Maria Oliviero

The purpose of this paper is to investigate the impact of ligament shape on radiative behavior, with a specific focus on the inter-dependence among porosity, ligament shape and…

232

Abstract

Purpose

The purpose of this paper is to investigate the impact of ligament shape on radiative behavior, with a specific focus on the inter-dependence among porosity, ligament shape and radiative characteristics.

Design/methodology/approach

Using Surface Evolver to generate a base structure and then coherently modifying it, the model presented in this paper aims to tackle these challenges in an improved fashion, all the while making it possible to systematically assess the influence of ligament shape on radiation heat transfer in foams, focussing on the porosity-dependence of ligament shape.

Findings

It is found that the prediction of numerical models, at constant size and specific surface of the cells, is strongly affected by the dependence of ligament shape on the porosity.

Research limitations/implications

The above said dependence has, therefore, to be accounted for in robust modeling of radiation in foams with a wider range of porosities.

Originality/value

The radiative behavior of metal foams has been studied in literature using analytical, numerical and experimental approaches. However, only few researches focussed their attention on the assessment of the relevance of specific micro-structural (i.e. sub-cell size) characteristics.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 2
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 9 September 2022

Hande Bakırhan, Hilal Yıldıran and Tuğba Uyar Cankay

This study aims to elucidate the relationship between nutritional status and various biochemical parameters and migraine symptoms.

164

Abstract

Purpose

This study aims to elucidate the relationship between nutritional status and various biochemical parameters and migraine symptoms.

Design/methodology/approach

The disability of individuals aged 19–64 years old with episodic migraine (n = 80, female n = 64, male n = 16) was assessed with the Migraine Disability Assessment Scale, and migraine severity was evaluated with the visual analog scale. The metabolic risks of individuals were determined by analyzing body composition, various biochemical parameters and anthropometric measurements. Nutrients and energy intake levels were measured using the food consumption recording form.

Findings

Body muscle mass percentage was correlated directly with migraine severity and inversely with the attack duration (r = 0.26, p = 0.01 and r = −0.29, p = 0.007, respectively). High bone mass was associated with low attack frequency (r = −0.23, p = 0.03), while high body fat percentage was associated with long attack duration (r = 0.28, p = 0.009). A significant direct correlation was found between total cholesterol level and migraine severity and attack duration (r = 0.25, p = 0.02) and between triglyceride level and attack duration (r = 0.26, p = 0.01). There was a direct correlation between serum thyroxine (T4) level and migraine attack severity (r = 0.23, p = 0.03). There was a significant direct correlation between energy and carbohydrate intake and migraine severity (r = 0.26, p = 0.02 and r = 0.30, p = 0.009, respectively), protein and vitamin B2 intake and attack frequency (r = 0.24, p = 0.03 and r = 0.23, p = 0.04, respectively) and an inverse correlation between monounsaturated fatty acid, fiber and vitamin C intake and migraine severity score (r = −0.35, p = 0.002; r = −0.25, p = 0.02; and r = −0.41, p = 0.001, respectively).

Originality/value

The findings confirm that nutritional status, body composition and some biochemical parameters can affect the course of migraine.

Details

Nutrition & Food Science , vol. 53 no. 3
Type: Research Article
ISSN: 0034-6659

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