Environmental Science
S. Pourkarimi; A. Hallajisani; A. Alizadehdakhel; A. Nouralishahi
Abstract
BACKGROUND AND OBJECTIVES: In this study, the characteristics of bio-oil samples produced through slow pyrolysis of two different macroalgae, i.e. Azolla filiculoides and Ulva fasciata, at optimized conditions were determined and compared.METHODS: For this purpose, the effects of temperature (300-500 ...
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BACKGROUND AND OBJECTIVES: In this study, the characteristics of bio-oil samples produced through slow pyrolysis of two different macroalgae, i.e. Azolla filiculoides and Ulva fasciata, at optimized conditions were determined and compared.METHODS: For this purpose, the effects of temperature (300-500 °C), carrier gas flow rate (0.2-0.8 L/min), and heating rate (10-20 °C/min) on the final bio-oil production were optimized using response surface methodology established by a central composite design.FINDINGS: The highest bio-oil yield from U. fasciata (34.29%) was obtained at the temperature of 500 °C, nitrogen flow rate of 0.2 L/min, and heating rate of 10 °C/min. As for A. filiculoides feedstock, the highest bio-oil yield (30.83%) was achieved at the temperature of 461 °C, nitrogen flow rate of 0.5 L/min, and heating rate of 20 °C/min. Both bio-oil samples contained saturated and unsaturated hydrocarbons. However, the average hydrocarbon chain length was relatively shorter in U. fasciata bio-oil (C4-C16) than in bio-oil from A. filiculoides (C6-C24). Although both bio-oils had almost identical heating values, the U. fasciata bio-oil showed more appropriate properties, i.e. lower viscosity and density. Furthermore, the energy recovery from U. fasciata pyrolysis was calculated as 56.6% which was almost 1.5 times higher than the energy recovery from A. filiculoides pyrolysis.CONCLUSION: The results indicated that U. fasciata bio-oil, with its superior characteristics, could be proposed as a promising candidate for application in diesel-based automotive industries.
Environmental Science
Z. Mohebi; H. Mirzaei
Abstract
BACKGROUND AND OBJECTIVES: Assessment of biodiversity is a key factor in understanding of function and ecosystem management. Nevertheless, an operating procedure for assessing biodiversity and spatial pattern has not been established yet. Therefore, this empirical study was conducted to explore the role ...
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BACKGROUND AND OBJECTIVES: Assessment of biodiversity is a key factor in understanding of function and ecosystem management. Nevertheless, an operating procedure for assessing biodiversity and spatial pattern has not been established yet. Therefore, this empirical study was conducted to explore the role of diversity of species in the spatial patterning of tow shrub herbaceous communities. METHODS: First, the biodiversity analysis was performed by Past3 software to compare the relationship between the two communities. Secondly, the distance and quadrat indices were employed to explore the spatial relationship of dominant species with diversity. In this regard, 64 and 84 plant species recorded in two vegetation types were investigated. Distribution patterns were extracted by distance and quadrat indices and Ecological Methodology software.FINDINGS: The results showed that vegetation type 2 had more diversity and richness compared to vegetation type 1. Besides, the spatial distributions of dominant species (Astragalus gossipinus and Bromus tomentellus) in the two vegetation types were clumped and random with tendency to be clumped. The Scrophulariaceae, Malvaceae, Papaveraceae, and Euphorbiaceae families were not found in vegetation Type 1, and vegetation Type 2 had no species of the Boraginaceae, Rosaceae, Thumeliaceae, Capparidaceae, Oleaceae, Sistaceae, and Dispaceae families. The results showed significant differences in the number of Gaminae and Legominosea families between the two vegetation types. CONCLUSION: It was concluded that in communities with a dominant cover of shrub, the distribution pattern was clumped, and quadrat indices were less efficient than distance indices. While, in high-diversity communities with a predominant cover of gross, spatial distribution was random and distance and quadrat indices were more convergent.
Environmental Science
H. Nouri; J. Mohammadi Roushandeh; A. Hallajisani; A. Golzary; S. Daliry
Abstract
BACKGROUND AND OBJECTIVES: Bioenergy is a phenomenon that has attracted humans’ attention for about a century. The desirable biological properties of chlorella sp.microalgae have turned it to one of the most ideal options for the production of biodiesel. However, the economic issues must be taken ...
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BACKGROUND AND OBJECTIVES: Bioenergy is a phenomenon that has attracted humans’ attention for about a century. The desirable biological properties of chlorella sp.microalgae have turned it to one of the most ideal options for the production of biodiesel. However, the economic issues must be taken into account in its industrial scale production. The present study aims to investigate chlorella sp. biomass production and growth conditions by studying the influence of glucose concentration as a carbon source, nitrate concentration as a nitrogen source and pH, as three of the most important factors.METHODS: For this purpose, design of experiment was done by response surface methodology and each factor was investigated simultaneously under glucose concentration in 2-20 g/L, nitrate concentration in 0-1 g/L and 6FINDINGS: The results indicated that carbon concentration has maximum effect on growth and biomass production. The best results were obtained in glucose concentration of 2.6-6 g/L, nitrate concentration of 0.2-0.5 g/L and pH values 7-9. Moreover, the maximum biomass production (1.31 g/L), the highest specific growth rate (0.167 1/day), and the highest biomass productivity (0.085 g/L/Day) were obtained in the following conditions: glucose concentration of 2.6 g/L, nitrate concentration of 0.5 g/L, and pH = 8. The optimal C/N ratio was determined and significant correlation was observed between pH and growth rate change.CONCLUSION: It was concluded that Chlorella sp < /em>., if properly adjusted for both chemical and physical parameters could be a valuable source of biomass for biodiesel production in industrial scale.
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