Iranica Journal of Energy & Environment
Volume:5 Issue: 1, Winter 2014

bioethanol was produced by Saccharomyces cerevisiae using oil palm trunk (OPT) sap supplemented with palm oil mill effluent (POME) in a shake flask culture. Four variables namely OPT sap to POME ratio,inoculum size, pH and incubation time were chosen to investigate their effects on production of bioethanol using One -Factor -at -a -Time (OFAT) method. The optimum process conditions were found to be at OPT sap to POME ratio of 30:20 and inoculum size of 4% v/v. The fermentation process exhibited better result in slightly basic media. The bioethanol concentration at the optimum condition was 12.52 g/l which equal to bioethanol yield of 44% g/g after four days of fermentation. It was found that the cell growth followed a sigmoidal trend. Logistic model, Luedeking-Piret model and Luedeking-Piret-like model were chosen and validated to describe the behavior of dry weight of the biomass, bioethanol production and glucose consumption, respectively. All selected models fitted well to experimental data, proven by high R2 values (>0.9) and low RMSE values.

Saccharomyces cerevisiae is known as the most widely used eukaryotic microorganism for biological studies. In present study, cell growth profile of Saccharomyces cerevisiae in a batch submerged culture was evaluated with three different non-structured kinetic models. Fitness assessment of experimental data on cell growth by models was performed using the curve-fitting tool in Excel and Mat-lab software. Obtained results showed Verhulst kinetic model with R2 equal to 0.97 was the most appropriate to describe the biomass growth rate of Saccharomyces cerevisiae. Maximum specific cell growth rate by Verhulst model was 0.59 h 1. Other kinetic constants were also determined for all the studied models.

This paper presents results of design, analysis, manufacturing and testing of a spiral horizontal axis wind turbine. In first step, modeling and computational fluid dynamic (CFD) analysis was performed. Helix blades angle for spiral rotors of outer and inner diameter of 0.85 and 0.45m, respectively was optimized. In the second step, as per optimized spiral rotor dimensions, a prototype was manufactured. Experiments were carried out for torque and power calculations; obtained results are discussed.

Consumption of Polyunsaturated fatty acid omega-3 is the most recommended fatty acids which have a health benefits for brain, kidney and eye. The conversion of plant-derived omega-3 (n3) -linolenic acid (ALA, 18:3n-3) to long-chain eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) can enhance ALA sufficient diets in compare to ALA deficient diets. Alpha-linolenic acid (ALA) was extracted and enriched from flax seed oil. Commercial lipases Candida rugosa, Pseudomonas cepacea and P. fluorescens were used for transesterification of ALA enriched from flax seed oil into olive oil TAG back bone. Gas chromatography of olive oil showed it contained high amounts of oleic acid (C18:1, n 9), linoleic acid (C18:2, n-6) and palmitic acid (C18:0) with 0% of ALA. Among the commercial lipase C. rugosa has more preference to ALA and 27% of ALA was incorporated to TAG back bone of olive oil. In 2 hours reaction time, the ALA concentration in TAG of olive has increased to 26% while oleic acid decreased to 60% and palmitic acid decreased from 25 to 7%. The highest incorporation of ALA into olive oil (29%) occurred for ALA: olive oil mole ratio (1:2). There was a decline in incorporation of ALA in olive oil backbone with an increase in the amount of water. ALA incorporation of 25% occurred with 100 μl water while without water it was 27%; it decreased to 15% with 1 ml of water.

Polyacrylamide (PAM) is known to pose a hazard to human health. A newly explored plant based flocculant, malva nut gum (MNG) is hypothesized to treat water and as a green material. This study investigates the biodegradation, thermal degradation and photodegradation of MNG and its flocculation capability. The results show MNG has a high biodegradation rate and low oxygen consumption rate. MNG biodegraded at Day-17, whilst, PAM did not show completion of biodegradation by the end of the experiment. Thermal degradation analysis shows MNG has a few decomposition stages and ash content. The photodegradation analysis shows photochemical changes in the structure of MNG and PAM. Factorial experiments show pH, concentration of cation and the concentration of MNG were the influential factors in coagulation-flocculation process. Optimization study observed 97% turbidity reduction at pH 5.77, the concentration of cation at 0.05 mM and the concentration of MNG at 0.42 mg/L. Conclusively, MNG operates effectively at near neutral pH and at low concentration. Such results strongly suggest that MNG is a suitable candidate, which could be used to replace PAM, as flocculant in water treatment.

This paper presents an intelligent state feedback controller of a non-inverting buck-boost converter for fuel cell power sources. The proposed control strategy uses fuzzy logic control and state feedback control in order to combine advantages of both controllers. Fuel cell DC/DC converters often have to be able to both step-up and step-down the input voltage and provide a high efficiency in the whole range of output power. Non-inverting buck-boost converters provide both step-up and step-down characteristics. In this paper a statespace average model of converter is obtained and the effect of using a state feedback controller in order to stabilize and regulate the output voltage has been proposed. The use of intelligent state feedback controller allows choosing the proper pole placement of system and using inductor current as a feedback provides a fast dynamic response. Simulation results showed the capability of proposed control strategy during different conditions in fuel cell electric vehicles.

Stringent emission regulations on diesel-powered vehicles and some of biodiesel emissions have led to development of new technologies to reduce emission of nitrogen oxides (NOX). Out of the choices available, Selective Catalytic Reduction (SCR) has shown to be the most promising exhaust after treatment system for reducing oxides of nitrogen in the near term in-use applications. SCRs use the ammonia containing compound urea, as a reducing agent. This paper describes an experimental investigation of Urea SCR,which has been designed for comparing efficiency of the SCR system for diesel and biodiesel. For this study, a SCR exhaust system was tested on a steady state, direct injection Kirloskar single cylinder diesel engine. Mahua Methyl Ester (MME) oil has used as a biodiesel. From the experimentation, it was concluded that the conversion efficiencies were higher for diesel comparable to biodiesel. The analysis also shows the Urea SCR system has a maximum of 93.4% NOX conversion efficiency of diesel fuel. For biodiesel, maximum NOX conversion efficiency of Urea-SCR was approximately 49%. This experimentation also revealed that the Urea SCR system hasan excellent HC conversion efficiency at all engine loads and using both fuels.

An artificial neural network (ANN) was used to forecast natural airborne dust as well as five gaseous air pollutants concentration by using a combination of daily mean meteorological measurements and dust storm occurrence at a regulatory monitoring site in Kermanshah, Iran for the period of 2007-2011. We used local meteorological measurementsand air quality data collected from three previous days as independent variables and the daily pollutants records as the dependent variables (response). Neural networks could be used to develop rapid air quality warning systems based on a network of automated monitoring stations. Robustness of constructed ANN acknowledged and the effects of variation of input parameters were investigated. As a result, dust had a decreasing impact on the gaseous pollutants level. The prediction tests showed that the ANN models used in this study have the high potential of forecasting dust storm occurrence in the region studied by using conventional meteorological variables.

Xylanase, laccase and manganese peroxidase (MnP) were produced and optimized by three strains of white rot fungi Phanerochaete􀀃sordida MRL3, Lentinus􀀃pigrinus􀀃MRL6 and Poliporus􀀃caliatus􀀃MRL7. These strains were initially isolated from wood decaying samples and then screened on minimal salt media,xylanase activities for the above strains were 55, 77.4 and 64.8 IU/mL, respectively. In addition, laccase activities were 80.65, 112.91 and 101.61 U/L, respectively. The activities forMnP were 123, 182.6 and 106.6 U/L, respectively. The maximum xylanase activity was observed at pH: 5.0, 30°C after 216 hours of incubation period. The maximum activities were 272.7, 278.52 and 292.8 IU/mL and the total protein was 1.24, 1.2 and 1.16 mg/mL, respectively. The maximum laccase activity was observed after 192-216 hours of incubation period, at pH: 5.0 on 30°C, the activities were 483.9, 516.4 and 459.67 U/L and the total protein 1.03, 1. and 1 mg/ml, respectively.The MnP activities were observed after 192-216 hours, at pH: 5.0 on 30°C, the activities were 588.66, 645.16 and 585.27 U/L and the total protein 1, 1.1 and 0.96 mg/mL, respectively.

The prospect of LNG could become a major global energy source is one of the most debated issues. The Liquefied Natural Gas (LNG) supply chain and the properties that make this fuelenvironmental friendly is in high demand for energy supply. In this paper, at first, the process of converting the natural gas to LNG was simulated; then, the process is optimized to archive minimum energy consumption per ton of LNG produced. Using a three stage exchanger is the best way for minimization of energy consumption in LNG production unit. Outlet pressure from the compressor and also type of refrigerant in cooling system is very effective on rate of energy conservations. The best mass fraction for refrigerants in liquefaction cycle are 0.8 for methane and 0.12 for ethane. For subcooling cycle that fraction is defined as 0.6 for methane and 0.4 for nitrogen. The optimized pressure in outlet of compressors in liquefaction cycle is 650 kPa; also, for the subcooling cycle is 1800 kPa. The amount of consumed energy was 14.91 kW per ton of produced LNG.

In this study, waste cooking oil methyl ester (WCOME) and diesel were blended in 20,, 60 and 80% percentage volume basis. Biodiesel and the blends were tested in 4-cylinders, 4-strokes and direct injection diesel engine to investigate the emissions and performance at engine speeds of 600-300 rpm under idle and full load. The result was compared to the data of petroleum diesel. The experimental data showed that the emissions of biodiesel and blends were much lower than B100. In comparison, the emission of biodiesel was more than 50% lower than B100. The average reductions were 76.19% for smoke opacity; and 97.62, 90.36 and 98.69% for brake specific emission factors of BS-HC, BS- CO and BS-SO2, respectively. The engine performances were also observed. Results showed that when WCOME were used both BHP and BMEP showed slight reductions about 8.63% compared to diesel. However, higher fuel consumption, had been indicated by the BSFC. The BSFCs of B100 were recorded to be 9.45% higher than biodiesel. The Highest BTEs were also recorded at a maximum average percentage of 19.93%.

Weather data can vary significantly from year to other, so there is a need to create a Typical Meteorological Year (TMY) data to represent the long-term typical weather data sets which are very important as inputs in modeling, designing and performance evaluation of energy balance calculations. In present study Finkelstein-Schafer statistical method was employed to analyze the long-term measured weather data of a 30-year period (1971-2000) for Baghdad province, which included six major meteorological parameter (Global solar Radiation, Sunshine Duration, Maximum, Minimum and Mean Temperature, Relative Humidity) Typical meteorological months from the period of considered years were selected by choosing the smallest (FS) deviation from the long-term of a TMY for Baghdad province.

Closed space sublimation (CSS) technique was used to deposit pure (99.99%) zinc selenide(ZnSe) powder on to glass substrates for fabricating the ZnSe thin films. The temperatures of source, substrate and the deposition time were optimized to deposit thin films of different thicknesses. Silver (Ag) was used as a dopant by ion exchange process in the ZnSe thin films. The structural analysis showed that as-deposited ZnSe thin films were polycrystalline having preferred orientation [111] direction. Micro structural parameters such as crystallite size, lattice parameter were determined using X-rays diffraction (XRD). Grains boundaries, roughness on surface and the grain density of the thin film samples were measured by scanning electron and atomic force microscopy before and after Ag doping.As-deposited, Ag-doped ZnSe samples before and after annealing were optically characterized by spectrophotometer in ultra violet, visible and infrared regions. The energy band gap of as-deposited ZnSe thin films for varying thicknesses were ranging from 2.62-2.67 eV which was reduced after Ag doping.The electrical properties showed that as-deposited thin films were highly resistive of the order of 108 -cm and after Ag immersion, it was reduced to 1 -cm. Deposition parameters and Ag doping influenced the structural, surface, optical and electrical properties.

Fifteen cyanobacteria species were isolated from fresh water and marine water resources from different parts of Tamil Nadu, India. Based on their morphological features they were identified through microscopic observations. The isolates were then screened for PHB production using nile red staining. It was found eleven of them were capable of producing PHB in their native forms. Further, PHB quantitative analysis by HPLC showed marine Phormidium sp with 7.60±0.005 mg/L (7.6%) of PHB, followed by Synechococcus sp with 4.59±0.012 mg/L (4.5%), Synechocystis sp with 3.74±0.007 mg/L (3.7%) and Anabaena sp with 2.31±0.012 mg/L (2.3%) of fresh water isolates. Among the isolates, Phormidium sp (VIT-BMN3) isolated from marine environments is reporting first time for its PHB production. In addition, biodegradable polymer extracted in hot chloroform is analysed by FTIR which showed strong bands near 1725 cm 1, 2977 cm 1 and 3437 cm 1 wave numbers and confirms the presence of ester carbonyl group (C=O), methylene C-H vibration and terminal OH group of PHB, respectively. Overall, nile red staining, HPLC analysis and FTIR spectrums obtained for all cultures conforms the PHB production by our isolates in their native conditions. Further studies of media optimization for increased PHB production are under the process.