Faculty of Engineering، Department of Chemical Eng.

In the present work the production of biodiesel using bitter almond oil (BAO) in a potassium hydroxide catalyzed transesterification reaction was investigated. The BAO was obtained from resources available in Iran and its physical and chemical properties including iodine value, acid value, density, kinematic viscosity, fatty acid composition and mean molecular weight were specified. The low acid value of BAO (0.24 mg KOH/g) indicated that the pretreatment of raw oil with acid was not required. The fatty acid content analysis confirmed that the contribution of unsaturated fatty acids in the BAO is high (84.7 wt.%). Effect of different parameters including methanol to oil molar ratio (3–11 mol/mol), potassium hydroxide concentration (0.1–1.7% w/w) and reaction temperature (30–70 °C) on the production of biodiesel were investigated. The results indicated that these parameters were important factors affecting the tranesterification reaction. The fuel properties of biodiesel including iodine value, acid value, density, kinematic viscosity, saponification value, cetane number, flash point, cloud point, pour point and distillation characteristics were measured. The properties were compared with those of petroleum diesel, EN 14214 and ASTM 6751 biodiesel standards and an acceptable agreement was observed.

The comminution of fuelwood for efficient transportation and handling exposes the material to various biological and chemical decomposition processes. The stockpiling of fuel chips can result in significant dry matter losses (DML) and consequent release of CO2 into the atmosphere. The decomposition processes could be controlled by managing the chip moisture content (MC). MC control by utilizing the self-heating of stockpiled stemwood chips together with wind-driven ventilation was tested in a practical storage experiment, using uncovered and plastic-covered piles as references. The data were analyzed with linear mixed models. The predicted DML was 2.4–3.8% during the monitoring period of 5.9 months, but no significant differences appeared between the storage treatments. The increase in the basic density of the chips decreased DML. On average 1.7–3.5% of the recoverable energy content of the chips was lost during the experiment. The predicted average decline in the MC was ca. 4–8 per...

Trimetallic oxide CuCrNiO nanoparticles (NPs) were successfully synthesized from their precursor salts including CuSO4.5H2O, Cr(NO3)3.9H2O, and Ni(NO3)2.6H2O in a facile and green method using aqueous leaf extract of Eryngium campestre as reducing and stabilizing agents. NPs were characterized using UV-vis spectroscopy, FTIR, EDX, XRD, and FESEM showing that trimetallic oxide NPs were synthesized in the form of nanoplates with the thickness of 18.73 nm and crystallite size of 17.39 nm.

In this work, we investigated the loading and conjugation of Curcumin on oleic acid (OA) and citric acid (CA) functionalized iron oxide nanoparticles and its applications in improving contrast in MRI. Magnetic iron oxide nanoparticles (Fe3O4, MNPs) were synthesized using the co-precipitation method and characterized by XRD, DLS, FT-IR, VSM, and SEM. FT-IR results confirmed functionalization with oleic acid and citric acid. Curcumin was loaded and conjugated with the Nano-Systems and the amount of Curcumin loaded was quantified using spectrophotometry at 419 nm wavelength. The impact of solvent on the loading of Curcumin was studied. The wt% of loaded Curcumin was found to be 0.189 wt% using dimethylformamide (DMF) whereas using a combination of water-ethanol (15% v/v), this increased to 56.149 wt%. T2 relaxation time was determined using a 1.5 Tesla MRI machine; results showed that the MNPs reduced T2. Cytotoxicity of Nano-Systems (NS) in MTT assay showed that concentrations higher ...

Magnetic nanoparticles (MNPs) were prepared by a co-precipitation method and thiol and urea functionalized using (3-mercaptopropyl) trimethoxysilane (MPTS) and 1-(3-trimethoxysilyl propyl) urea (TMSPU). The samples were characterized by SEM, XRD and FTIR, and BET surface area measurement and used for immobilization of Candida rugosa lipase type VII (CRL7) and Thermomyces lanuginosus lipase (TLL) for a transesterification reaction. The loading capacities of the lipases immobilized on the functionalized MNPs were also studied. The activity and thermal stability of the immobilized lipases were compared to those of the free enzymes too. The loading capacities of CRL7 and TLL on MNPs-TMSPU are 410 and 440 mg/g-MNPs, 5.9 and 5.5 times higher than those on the unfunctionalized MNPs, respectively. The initial activities of both CRL7 and TLL on MNPs-TMSPU are higher than those on MNPs-MPTS. After 30 min incubation at 80 °C, the remained activity of TLL on MNPs-TMSPU is 2.5 times higher than ...

This project attempts to evaluate the effect of nanofluids on thermal performance and the economic parameters of shell and tube heat exchangers. First, two thermodynamic processes including combined heat and power (CHP) system and solar-driven organic Rankine cycle (ORC) are simulated using the Aspen HYSYS. The CHP and ORC systems can produce 25 MW and 175.8 kW of electrical power, respectively. Thereafter, to use the nanofluids in the heat exchangers of these systems, the thermophysical specifications are modeled in the MATLAB software and validated with previous investigations. For this purpose, four kinds of nanofluids consisting of Al2O3/H2O, TiO2/H2O, Cu/H2O and Ag/H2O are utilized. According to the results, by adding the nanoparticles to the base fluid, the thermal conductivity, viscosity, heat transfer coefficient and density increase and the heat capacity reduces. The economic assessment and parametric analysis on concentration of the nanoparticles are conducted. The variati...

A 2D multi-physic in-house-model has been developed to analyse the performances of Solid Oxide Electrolysis Cell (SOEC) stack. This model encompasses a combined electrochemical and thermal description of the electrolyser. An analytical solution for multi-species diffusion across the porous cathode has been implemented in the model. This numerical tool is useful to provide all the important parameters of the stack operation: distribution of temperature, heat fluxes, local current densities, gas concentrations and overpotentials. Simulations show that thermal equilibrium of the stack is strongly dependant on radiative heat losses, whereas convective heat transfers are limited. In the exothermic operation mode, the cell warming depends on the radiation efficiency. A parametric study has been carried out to analyse SOEC irreversible losses. It is found that the anode activation overpotential is significant, whereas the polarisation due to the cathode activation remains much more limited. Anode concentration overpotentials are found to be insignificant whatever the operating condition. Cathode concentration overpotentials are found to be moderate in the case of Electrolyte Supported Cell (ESC), while they can increase drastically with current density in the case of Cathode Supported Cell (CSC). Addition of diluent gases into the H 2 , H 2 O mixture is found to increase the concentration overpotentials.