A Comparative Simulation Study of the Thermal Performances of the Building Envelope Wall Materials in the Tropics

he building walls which form the major part of the building envelope thermally interact with the changing surrounding environment throughout the day influencing the indoor thermal comfort of the space. This paper aims at assessing in detail the different aspects (thermophysical properties, thickness, exposure to solar heat gain, etc.) of opaque building wall materials affecting the indoor thermal environment and energy efficiency of the buildings in tropical climate (in the summer and winter days) by conducting simplified simulation analysis using the Integrated Environmental Solutions Virtual Environment (IES-VE) program. Besides, the thermal efficiency of a number of selected wall materials with different thermal properties and wall configurations was analysed to determine the most optimal option for the studied climate. This study first developed the conditions for parametric simulation analysis and then addressed selected findings by comparing the thermal responses of the materials to moderate outdoor temperature and energy-saving potential. While energy consumption estimation for a complete operational building is a complex method by which the performance of the wall materials cannot be properly defined, as a result, this simplistic simulation approach can guide the designers to preliminary analyse the different building wall materials in order to select the best thermal efficiency solution

Total Antioxidant Activity, and Hesperidin, Diosmin, Eriocitrin and Quercetin Contents of Various Lemon Juices

Purpose: To investigate 38 natural and 62 branded lemon juices for their total antioxidant activities and flavonoid content.Methods: The ferric reducing antioxidant power was applied to evaluation of antioxidant. Additionally quercetin, eriocitrin, diosmin and hesperidin contents were evaluated by high performance liquid chromatography (HPLC).Results: Total antioxidant activity of the juices ranged from 91.38 ± 0.01 to 526.93 ± 0.12 μg/ml. The maximum contents of quercetin, hesperidin and eriocitrin 14.83 ± 2.83, 104.84 ± 12.58 and 10.68 ± 2.41 μg/mL, respectively. The natural juices had diosmin levels as high as 236.18 mL. The limit of detection (LOD) ranged from 0.15 μg mg-1 for hesperidine to 0.53 μg ml-1 for diosmin while the limit of quantification (LOQ) ranged from 0.27 μg mg-1 for hesperidine to 0.93 μg ml-1 for quercetin.Conclusion: The developed method can also be applied to the determination of related extracts of orange cultivars as well as various extracts of medicinal plants.Keywords: Antioxidant, Flavonoid, Hesperidin, Diosmin, Eriocitrin, Quercetin, Lemon juic

Profiling of major fatty acids in different raw and roasted sesame seeds cultivars

The aim of this study was to investigate the fatty acids profile of five sesame cultivars including Branching Naz, Darab, Karaj, Dezful and Black sesame and the effect of time and temperature roasting procedure. The seeds oil content varied from 43±0.28 to 47±0.41% with the average content of 44.4±1.87%. Darab and Black sesame cultivar had the highest and lowest oil content respectively. Oleic and linoleic acids were the two-dominant fatty acids in the sesame seed oil about 80 to 85% of the total amount, whereas palmitic and stearic acids were present at 12 to 15%. Moreover, Dazful and Black sesame had the maximum and minimum content of oxidizability value respectively. The results of the present study showed that the fatty acid contents in studied cultivars were steady during different roasting conditions and fatty acid behavior of samples was good fitted with the high temperatures.Key words: Gas chromatography (GC), fatty acid, roasting procedure, sesame seed, stability

Eggshell and Walnut Shell in Unburnt Clay Blocks

Agricultural residues/by-products have become a popular choice for the manufacturing of building materials due to their cost-effectiveness and environmental friendliness, making them a viable option for achieving sustainability in the construction sector. This study addresses the utilisation of two agro-wastes, i.e., eggshell and walnut shell, in the manufacture of unburnt clay blocks. The experiments were carried out on three series of samples in which first eggshell (10–50%) and walnut shell (5–20%) were incorporated individually and then combined (5% walnut, 10–30% eggshell) in the mixture to assess their influences on the physical and mechanical properties of the unburnt clay blocks. This study performed the following tests: Density, capillary water absorption, linear shrinkage, flexural and compressive strength. The results indicated that eggshell enhanced the strength relative to the control sample when the materials were employed individually, but walnut shell lowered it. Moreover, combining the two materials in the mixer reduced the strength of the samples even further. Nevertheless, the inclusion of the waste materials decreased the density, capillary water absorption coefficient and linear shrinkage of the samples. The findings indicate that eggshell has great potential for unburnt clay block manufacture. However, walnut shell integration needs further research

Application of agro and non-agro waste materials for unfired earth blocks construction: A review

The production process of conventional building materials consumes a high amount of energy which has a negative impact on the environment. The use of locally available materials and upgradation of traditional techniques can be a good option for sustainable development. Consequently, earth has attracted the attention of the researchers as a building construction material for its availability and lower environmental impact. On the other hand, in developing countries waste disposal from the agricultural and industrial sectors raises another serious concern. The scientists have introduced such waste additives into the earth matrix to improve its performance. Therefore, the present paper reviews the state-of-the-art of research on the effects of these various agro and non-agro wastes in the production of unfired earth blocks. This study is divided into three sections: The first section outlines the different types of waste materials and earth blocks considered in the selected papers. The second part deals in depth with the test results of the different properties (density, water absorption, compressive strength, flexural strength and thermal conductivity) of unfired earth blocks containing waste materials. The last section analyses and compares the results with the current earth-building construction standards. The literature survey presents that the waste materials have a clear potential to partly replace earth by complying with certain requirements. Moreover, the application of such wastes for the development of building construction materials provides a solution that decreases energy usage as well as contributes to effective waste management. Future research on establishing guidelines and standards for the development and production of these sustainable unfired earth building materials is recommended

Thermophysical Properties of Sawdust and Coconut Coir Dust Incorporated Unfired Clay Blocks

Sawdust and coconut coir dust are agro-wastes/by-products which are suitable for use as raw materials to manufacture unfired clay blocks due to their excellent physical and mechanical properties. A limited number of studies have been conducted on the utilisation of these agro-wastes in clay block production, and they have mostly been devoted to investigating the physicomechanical properties, with less attention given to the thermal properties. Moreover, the majority of the studies have used chemical binders (cement and lime) in combination with agro-waste, thus increasing the carbon footprint and embodied energy of the samples. Furthermore, no research has been performed on the thermal performance of these agro-wastes when incorporated into clay blocks at the wall scale. Therefore, to address these limitations, the present study developed unfired clay blocks incorporating sawdust and coconut coir dust (0, 2.5, 5, and 7.5% by weight), without the use of chemical binders, and evaluated their thermal performance, both at the individual and wall scales. The experiments were divided into two phases. In the first phase, individual sample blocks was tested for basic thermal properties. Based on the results of the first phase, small walls with dimensions of 310 mm × 215 mm × 100 mm were built in the second phase, using the best performing mixture from each waste type, and these were assessed for thermal performance using an adapted hot box method. The thermal performance of the walls was evaluated by measuring the heat transfer rate from hot to cold environments and comparing the results to the reference wall. The results showed that thermal conductivity decreased from 0.36 W/mK for the reference sample, to 0.19 W/mK for the 7.5% coconut coir dust sample, and 0.21 W/mK for the 7.5% sawdust sample, indicating an improvement in thermal insulation. Furthermore, the coconut coir dust and sawdust sample walls showed a thermal resistance improvement of around 48% and 35%, respectively, over the reference sample wall. Consequently, the findings of this study will provide additional essential information that will help in assessing the prospective applications of sawdust and coconut coir dust as the insulating material for manufacturing unfired clay blocks

Influence of Sawdust Particle Sizes on the Physico-Mechanical Properties of Unfired Clay Blocks

Sawdust, which is a waste/by-product of the wood/timber industry, can be utilised as a valuable raw material in building material production due to its abundance and low cost. However, the application of sawdust in the manufacture of unfired clay blocks has received little investigation. Furthermore, the impact of different sawdust particle sizes on the properties of unfired clay blocks has not been studied. Therefore, this study screened sawdust at three different particle sizes: SP-a (212 μm < x < 300 μm), SP-b (425 μm < x < 600 μm) and SP-c (1.18 mm < x < 2.00 mm), to examine their effects on the physical and mechanical properties of unfired clay blocks. The density, linear shrinkage, capillary water absorption and flexural and compressive strengths were among the tests performed. Different sawdust percentages, i.e., 2.5%, 5%, 7.5% and 10% of the total weight of the clay, were considered. The tests results show that when sawdust was added to the mixture, the density of the samples reduced for all particle sizes. However, the linear shrinkage increased in SP-a samples but decreased in the other two particle size samples as the sawdust percentage increased from 2.5% to 10%. On the other hand, the capillary water absorption coefficient increased while the strength decreased with increasing sawdust content for all three groups. The highest compressive strength (CS) and flexural strength (FS) were achieved at 2.5% of sawdust content. Furthermore, it was observed that SP-b (CS—4.74 MPa, FS—2.00 MPa) samples showed the highest strength followed by SP-a (CS—4.09 MPa, FS—1.69 MPa) and SP-c (CS—3.90 MPa, FS—1.63 MPa) samples. Consequently, good-quality unfired clay blocks can be manufactured using sawdust up to 2.5% with particle sizes ranging between 600 and 425 μm

A statistical analysis of life cycle assessment for buildings and buildings’ refurbishment research

This study aims to examine the literature related to environmental Life Cycle Assessment (LCA) for buildings and buildings' refurbishment from 1994 to 2022 by implementing a statistical analysis based on 'Web of Science' databases. LCA is viewed as a consolidated process that measures the environmental performance of buildings and their services, aiming to address the potential environmental impacts over the life cycle of buildings. A total of 1336 retrieved journal publications for LCA for buildings and 169 journal publications for LCA in building refurbishment. The articles' patterns were investigated in terms of subject categories, journals, countries, and the most highly cited articles. The findings reveal that LCA publications for buildings and building refurbishment have increased over the period 1994–2022, with China being the leading country contributing to the largest number of articles and possessing the most significant influence, followed by the USA for LCA in buildings. While Portugal is the leading country, followed by Italy, for LCA Buildings' Refurbishments. 97.08% of the publications were written in English, 2.04% in German, and 0.68% in Spanish. French and Japanese were the remaining languages, each with one publication, accounting for 0.2% of the 1336 building LCA publications. In contrast to refurbishment, LCA publications were written in only two languages, English (98.7%) and German (1.3%). Results show that the subject area differs depending on the type of LCA publication, with building LCA focusing on construction engineering while refurbishment focused on environmental topics. According to the IF, the most influential journal was renewable & sustainable energy for buildings and refurbishment LCA. However, journal distribution within LCA is still limited, and assessment methods and theme analysis still need to catch up with a clear gap in LCA in environmental impact mitigation and analysis methodologies, which will be a prominent direction of future building LCA research