Browsing by Author "Soltani, Mohammad"

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    Households energy consumption and carbon dioxide emissions of Mahabad City, Iran
    (Universiti Teknologi Malaysia, 2020) Soltani, Mohammad
    This study seeks to find a method to identify the dominant pattern of energy choice and consumption in households, centring on demographic factors affecting the use of home appliances. To this aim, this research dealt with a variety of energy sources that were widely used by households, namely LPG, electricity, and kerosene for cooking, heating and cooling, lighting, and home appliances. Additionally, significant associations for household energy choice and consumption were identified for demographic variables, including household size, gender, age of household head, educational level, and income group. A binary logistic regression was performed to obtain quantitative data provided by a survey from 821 households across residential districts of urban and rural areas in Mahabad Region, northwest of Iran. Collected data were analyzed within a proposed three-energy dimensions model (3-ED). The results showed that if the other variables remain constant, income may lead to variation in LPG and electricity consumption. Unlike other independent variables, the household-head age failed to have a significant impact. The findings can contribute to a better understanding of effective factors on household energy choice and consumption in other cities and be useful for the support of policymakers in their consumption patterns. This research explores the impact of different household demographic characteristics on energy-saving behaviours and carbon dioxide (CO2) emissions in Mahabad city located in the northwest of Iran. The structural model adopted was composed of six variables, including household age, household size, educational qualification, income quintile, gender, and energy conservation behaviour concerning demographic features, energy sources, and consumptions. To compare the predictability power of these variables' effects on households' energy conservation and CO2 emissions, a crisp instruction on how to evolve a statistical technique for analyzing data was provided by Partial Least Squares Structural Equation Modelling (PLS-SEM). It was revealed that households consume approximately 89.71% on liquefied petroleum gas (LPG), 9.87% on electricity, and the rest 0.43% on kerosene, petrol, and diesel on a monthly basis. Eventually, the results of this research showed that age, family size, and carbon dioxide emissions, except education background and income level, are significantly correlated with energy-saving behaviour.
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    Optimization of the cordycepin production by cordyceps militaris in submerged culture
    (Universiti Teknologi Malaysia, 2018) Soltani, Mohammad
    Cordyceps militaris is a famous strain that produces a variety of bioactive compounds such as polysaccharides and nucleosides which have been used as medicine in traditional Chinese medicine (TCM). Cordycepin is a nucleoside produced by Cordyceps militaris. It shows high anticancer and antioxidant activities in vitro and in vivo bioassays. Therefore, cordycepin as a potential anticancer compound, is a good replacement for chemical-based drugs used in chemotherapy. In this work, optimization process was carried out to maximize cordycepin production in both shake flask and bioreactor using mushroom C. militaris DSM 23612 strain. For shake flask study, the medium composition was optimized using both one factor at a time (OFAT) and Response Surface Methodology (RSM) methods. The optimal medium for cordycepin production using OFAT was composed of (in gL-1): glucose (40.0), potassium nitrate (15.0), K2HPO4 (0.5), KH2PO4 (0.5), MgSO4.7H2O (0.5), and FeSO4.7H2O (3.0). In addition, the optimal medium composition by statistical optimization method was composed of (in gL-1): glucose (55.0), potassium nitrate (17.8), K2HPO4 (0.5), KH2PO4 (0.5), MgSO4.7H2O (0.5), and FeSO4.7H2O (2.5). The cordycepin at 318.51±1.26 mgL-1 was obtained using OFAT-optimized medium. The maximal cordycepin production (461.73 ± 2.72 mgL-1) was achieved using RSM optimized medium, which was approximately 1.44-fold higher than the one attained using OFAT optimized medium. Next, the process was optimized in 5-L stirred tank bioreactor. The amount of cordycepin produced were 446.1 mgL-1 and 381.82 mgL-1 in bioreactor without and with pH control, respectively. The aeration rate of 1.5 v/v/min was the best for cordycepin production. Furthermore, a series of fed-batch cultivations were carried out to determine the factors that limit the cell growth and cordycepin production. A combination of constant monocarbon (glucose) feeding with dissolved oxygen control was found to be the best strategy for maximum cordycepin production (814.19 mgL-1). In addition, the optimal extraction condition was using solvent-solvent mixture (v/v) containing hot water (23%), ethanol (30%), methanol (25%) and ethyl acetate (22%) with extraction temperature at 35 °C for 90 min. The extracted cordycepin has the purity of 81%. The significant findings from this study were successful utilization of potassium nitrate as inexpensive nitrogen source and scalable solvent based extraction technique in producing high amount of cordycepin