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Article

Md Delwar Hossain, Md Kamrul Hassan, Anthony Chun Yin Yuen, Yaping He, Swapan Saha and Waseem Hittini

The purpose of this study is to review and summarise the existing available literature on lightweight cladding systems to provide detailed information on fire behaviour…

Abstract

Purpose

The purpose of this study is to review and summarise the existing available literature on lightweight cladding systems to provide detailed information on fire behaviour (ignitibility, heat release rate and smoke toxicity) and various test method protocols. Additionally, the paper discusses the challenges and provides updated knowledge and recommendation on selective-fire mechanisms such as rapid-fire spread, air cavity and fire re-entry behaviours due to dripping and melting of lightweight composite claddings.

Design/methodology/approach

A comprehensive literature review on fire behaviour, fire hazard and testing methods of lightweight composite claddings has been conducted in this research. In summarising all possible fire hazards, particular attention is given to the potential impact of toxicity of lightweight cladding fires. In addition, various criteria for fire performance evaluation of lightweight composite claddings are also highlighted. These evaluations are generally categorised as small-, intermediate- and large-scale test methods.

Findings

The major challenges of lightweight claddings are rapid fire spread, smoke production and toxicity and inconsistency in fire testing.

Originality/value

The review highlights the current challenges in cladding fire, smoke toxicity, testing system and regulation to provide some research recommendations to address the identified challenges.

Details

Journal of Structural Fire Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2040-2317

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Article

S. Kasbioui, E.K. Lakhal and M. Hasnaoui

The investigation of heat transfer and fluid flow by mixed convection in a vertical rectangular cavity containing adiabatic partitions attached to the heated wall is…

Abstract

The investigation of heat transfer and fluid flow by mixed convection in a vertical rectangular cavity containing adiabatic partitions attached to the heated wall is numerically studied. The parameters governing this problem are the Rayleigh number (103≤Ra≤4×105), the Reynolds number (5≤Re≤100), the aspect ratio of the cavity (2.5≤A≤15), the partitions length (0.1≤B≤0.95), the aspect ratio of the micro cavities (0.33≤C≤0.66) and the Prandtl number (Pr=0.72). The results obtained indicate that the heat exchange between the system and the external medium, through the cold wall and the upper vent, are considerably affected by the presence of the partitions and for all the values of A and Ra considered. However, the quantity of heat released by the higher opening remains insensitive to the presence of the partitions; it depends only on the intensity of the forced flow. Moreover, it is shown that for critical values of Re and Ra, these rates of heat transfer pass by maxima of which the value is independent of A when this parameter is equal to or higher than 10. For high Reynolds numbers, the flow is dominated by forced convection for low values of Ra and high values of B. Finally, the competition between natural and forced convection occurs when Ra≥104. The heat transfer is correlated with the main parameters and presented for an eventual utilization in design.

Details

Engineering Computations, vol. 20 no. 2
Type: Research Article
ISSN: 0264-4401

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Article

Hariram Venkatesan, Godwin John J., Seralathan Sivamani and Micha Premkumar T.

The purpose this experimentation is to study the combustion characteristics of compression ignition engine fuelled with mineral diesel. The reason behind the numerical…

Abstract

Purpose

The purpose this experimentation is to study the combustion characteristics of compression ignition engine fuelled with mineral diesel. The reason behind the numerical simulation is to validate the experimental results of the combustion characteristics.

Design/methodology/approach

The numerical analysis was carried out in this study using MATLAB Simulink, and the zero dimensional combustion model was applied to predict the combustion parameters such as in cylinder pressure, pressure rise rate and rate of heat release.

Findings

Incorporating the dynamic combustion duration with respect to variable engine load in the zero dimensional combustion model using MATLAB Simulink reduced the variation of experimental and numerical outputs between 5.5 and 6 per cent in this analysis.

Research limitations/implications

Validation of the experimental analysis is very limited. Investigations were performed using zero dimensional combustion model, which is the very appropriate for analysing the combustion characteristics.

Originality/value

Existing studies assumed that the combustion duration period as invariant in their numerical analysis, but with the real time scenario occurring in CI engine, that is not the case. In this analysis, mass fraction burnt considering the dynamic combustion duration was incorporated in the heat transfer model to reduce the error variation between experimental and numerical studies.

Details

World Journal of Engineering, vol. 16 no. 3
Type: Research Article
ISSN: 1708-5284

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Article

Cao Junfeng

Through many years of study, we have found that cold quantum is the most important force in nature. Under the pressure of coldness on hotness, various materials are…

Abstract

Through many years of study, we have found that cold quantum is the most important force in nature. Under the pressure of coldness on hotness, various materials are formed. Under the pressure of cold quantum, these materials are provided with gravity, and celestial bodies start to move. The pressure of cold quantum exists in space and materials. It is the pressure of cold quantum that huge changes between the four seasons on the earth begin to appear. The whirlpool, produced from the cold quantum pressure, pushes all the celestial bodies making them turn and change. The coldness converts frozen water into ice, which could not be achieved by any other force. The extreme and powerful strength of cold quantum has been well‐known. Therefore, we claim that the cold quantum pressure is the greatest force which ever existed in the universe.

Details

Kybernetes, vol. 32 no. 7/8
Type: Research Article
ISSN: 0368-492X

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Article

Anna Wieprzkowicz and Dariusz Heim

The purpose of this paper is to investigate energy performance of thermal insulation modified by phase change materials (PCM). Special attention was paid to the problem of…

Abstract

Purpose

The purpose of this paper is to investigate energy performance of thermal insulation modified by phase change materials (PCM). Special attention was paid to the problem of proper performance assessment of such components by computational techniques and methods of its evaluation.

Design/methodology/approach

Analysis was conducted on the basis of the results obtained using the dynamic building simulation technique performed by ESP-r software. Two cases of insulation components enhanced by a layer: characterised by increased latent heat capacity were analysed and compared. Results were investigated in terms of thermal comfort and energy efficiency, using evaluation methods from literature and new, original indicators proposed by authors.

Findings

The analysis revealed that performance of insulation enhanced by PCM is very dynamic and highly sensitive to changeable weather conditions. Thus, there is a strong need for the development of the assessment methods and guidelines for the performance of such components with changeable physical properties.

Practical implications

The methodology and the results reported in this paper could be used as a guideline for further parametric studies and optimisation tasks. Further development of phase change insulation can substantially change the existing approach to the building energy performance.

Originality/value

The paper introduces a new approach of the assessment of insulation components modified by PCM and highlights the dynamic characteristics of its performance.

Details

Management of Environmental Quality: An International Journal, vol. 27 no. 6
Type: Research Article
ISSN: 1477-7835

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Article

J.G. Withers

THE alternative definitions of combustion efficiency based on the ratio of actual to theoretical heat releases and of theoretical to actual fuel requirements are…

Abstract

THE alternative definitions of combustion efficiency based on the ratio of actual to theoretical heat releases and of theoretical to actual fuel requirements are discussed in relation to the practical need for reckoning enthalpies above a datum temperature. Empirical expressions are obtained which enable the enthalpies of the reactants and the products of combustion to be calculated to an adequate standard of accuracy. The appropriate heat of combustion of the fuel is defined and the effect of temperature examined. The difference in calculated efficiencies obtainable from the alternative definitions are then determined under extreme conditions, and a practical formula developed. Finally, experimental errors in combustion efficiency determination are examined for both the heat balance and gas analysis techniques.

Details

Aircraft Engineering and Aerospace Technology, vol. 22 no. 8
Type: Research Article
ISSN: 0002-2667

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Article

Guocheng Zhu, Dana Kremenakova, Yan Wang and Jiri Militky

Clothing comfort has been one important and complex area which is the result of a balanced process of heat and moisture/liquid exchange between the human body, the…

Abstract

Purpose

Clothing comfort has been one important and complex area which is the result of a balanced process of heat and moisture/liquid exchange between the human body, the clothing system and the environment. And the clothes will represent different properties when they are in different conditions, which have great influence on human comfort. Therefore, the purpose of this paper is to investigate the hygroscopicity-exothermicity property of plain cotton fabric.

Design/methodology/approach

A real-time testing device for monitoring the temperature change of cotton fabrics after adsorbing liquids was constructed, and serveral liuqids such as water, NaCl solution with different concentrations, NaOH solution with different concentrations, and urea solution with different concentrations were used in this work.

Findings

It was found out that absorption of liquids by cotton fabric was followed by the liberation of heat, which increased the temperature of cotton fabric as well as the temperature of surrounding environment, and the process of temperature increase was much shorter than the process of temperature decrease. In addition, the released heat energy were different according to different liquids as well as the concentrations of liquid solutions.

Originality/value

There have some studies in the heat of water/vapor sorption of textiles. Here the temperature changes of surrounding environment and fabric after absorbing different liquids were real-time observed and recorded.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 4
Type: Research Article
ISSN: 0955-6222

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Article

Kannan Chidambaram and Vijayakumar Thulasi

The development of a theoretical model for predicting the combustion, performance and emission characteristics of a cylinder head porous medium engine becomes necessary…

Abstract

Purpose

The development of a theoretical model for predicting the combustion, performance and emission characteristics of a cylinder head porous medium engine becomes necessary due to imposed requirements from the viewpoint of power, efficiency and toxic gases in the exhaust. The cylinder head porous medium engine was found to have superior combustion, performance and emission characteristics when compared to a conventional diesel engine. The paper aims to discuss these issues.

Design/methodology/approach

Due to heterogeneous and transient operation of diesel engine under conventional and porous medium mode, the combustion process becomes complex, and achieving a pure analytical solution to the problem was difficult. Although, closer accuracy of correlation between the computer models and the experimental results is improbable, the computer model will give an opportunity to quantify the combustion and heat transfer processes and thus the performance and emission characteristics of an engine.

Findings

In this research work, a theoretical model was developed to predict the combustion, performance and emission characteristics of a cylinder head porous medium engine through two-zone combustion modeling technique, and the results were validated through experimentation.

Originality/value

The two-zone model developed by using programming language C for the purpose of predicting combustion, performance and emission characteristics of a porous medium engine is the first of its kind.

Details

Multidiscipline Modeling in Materials and Structures, vol. 12 no. 3
Type: Research Article
ISSN: 1573-6105

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Article

Saman Khalesi, Rosita Jamaluddin and Amin Ismail

Flaxseed (FL) is a nutrient rich seed but contains cyanogenic glycosides, which can release hydrogen cyanide (HCN) into the body after consumption. This study aims to…

Abstract

Purpose

Flaxseed (FL) is a nutrient rich seed but contains cyanogenic glycosides, which can release hydrogen cyanide (HCN) into the body after consumption. This study aims to determine the cyanogenic content of raw and heated (170°C, 15 min) flaxseed as well as its effect on the blood thiocyanate (SCN) concentration, a derivate of HCN, in rats. Changes in liver and kidney enzymes level of blood are further studied.

Design/methodology/approach

Rats were assigned into groups of control, 10 percent, 20 percent and 30 percent of either raw or heated FL, in basal diet, for duration of 30 days. Cyanogenic content of FL analyzed using picrate method and blood thiocyanate concentration analyzed using high performance liquid chromatography.

Findings

Raw ground flaxseed had 251.14±9.11 mg HCN/kg food, which significantly reduced by 8.5 percent after heating. Generally heated FL groups showed lower (but not significant) blood thiocyanate compared to raw FL groups. Blood SCN elevated by increasing the dosage of flaxseed. However, only in 30 percent raw FL group the difference was significant (p<0.05). Liver and kidney enzymes were not changed significantly in all groups (p>0.05). This study suggests that consumption of flaxseed in high dosage (20 percent to 30 percent) is better to be in heated form to result in lower blood thiocyanate concentration.

Originality/value

This study may provide better understanding for safer usage of flaxseed in animals and even human interventional studies and may be applicable to flaxseed consuming food industries.

Details

Nutrition & Food Science, vol. 43 no. 1
Type: Research Article
ISSN: 0034-6659

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Article

George Pichurov, Radostina Angelova, Iskra Simova, Iosu Rodrigo and Peter Stankov

The purpose of this paper is to integrate a thermophysiological human body model into a CFD simulation to predict the dry and latent body heat loss, the clothing, skin and…

Abstract

Purpose

The purpose of this paper is to integrate a thermophysiological human body model into a CFD simulation to predict the dry and latent body heat loss, the clothing, skin and core temperature, skin wettedness and periphery blood flow distribution. The integration of the model allows to generate more realistic boundary conditions for the CFD simulation and allows to predict the room distribution of temperature and humidity originating from the occupants.

Design/methodology/approach

A two-dimensional thermophysiological body model is integrated into a CFD simulation to predict the interaction between the human body and room environment. Parameters varied were clothing insulation and metabolic activity and supply air temperature. The body dry and latent heat loss, skin wettedness, skin and core temperatures were predicted together with the room air temperature and humidity.

Findings

Clothing and metabolic activity were found to have different level of impact on the dry and latent heat loss. Heat loss was more strongly affected by changes in the metabolic rate than in the clothing insulation. Latent heat loss was found to exhibit much larger variations compared to dry heat loss due to the high latent heat potential of water.

Originality/value

Unlike similar studies featuring naked human body, clothing characteristics like sensible resistance and vapor permeability were accommodated into the present study. A method to ensure numerical stability of the integrated simulation was developed and implemented to produce robust and reliable simulation performance.

Details

International Journal of Clothing Science and Technology, vol. 26 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

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