Iranica Journal of Energy & Environment
Volume:3 Issue: 4, Autumn 2012

Expanded bed adsorption (EBA) is an integration technology for capturing target bioproducts directly from unclarified feedstock, designing and applying a good adsorbent affects its performance. In present work, a novel matrix has been developed for expanded bed adsorption process. The prepared matrix was manufactured using water-in-oil emulsification method. Desirable adsorbents tend to be of small size, high density as well as high porosity. Here, the prepared matrices had regular spherical shape, wet density of 1.95, followed logarithmic normal size distribution within the range of 50-200 μm, mean diameter of 126.4 μm and 91.93% prosily. The Richardson-Zaki equation expressed the bed expansion and operation flow rate for the prepared matrix and Streamline DEAE. In addition, the theoretical prediction of correlation parameters (Ut and n) was also measured. To characterize the hydrodynamic properties in the expanded bed, the residence time distribution method was used. The physical and hydrodynamic properties of the fabricated matrix were studied and compared with those of the commercial Streamline DEAE matrix. The results indicated that the prepared matrices showed good expansion and stability in the bed and are thus suitable for expanded bed applications.

Bank erosion in populated areas could cause fatalities and property damage if banks collapse abruptly, compromising the integrity of residential buildings and civil facilities. Bank erosion study is in general a very complex problem because of it involves multi-processes such as bank surface erosion, bank toe erosion and bank material mechanic failure, etc. Each of these processes is related to several parameters: sediment size distribution, bank material cohesion, slope, homogeneity, consolidation, soil moisture and ground water level, as well as bank height. The bank erosion rate is also related to the strength of the flow in the river indicated by the flow shear stress, water depth and channel curvature, etc. In this study, the numerical model CCHE2D has been applied to study real-world bank erosion cases in a mountain river, Khoske Rud Farsan River, Iran, which is a braided river with high sediment loads and channel mobility; the bank erosion of this river is dominated by floods during rainy seasons.

Hydrogen production from steam reforming of methanol was performed in an adiabatic fixed bed heterogeneous reactor by using Cu/ZnO/Al2O3/CeO2 /ZrO2 nanocatalyst. The catalyst was prepared by co-precipitation method and characterized by TGA, XRD, SEM and BET. By changing the mean average temperature of the catalyst bed (or reactor operation temperature) from 230 to 270°C, variations in methanol conversion were monitored. The results showed that the conversion of methanol was strongly dependent on the reaction temperature. In addition, the effects of weight hourly space velocity (WHSV) on methanol conversion were investigated. According to the results, the maximum conversion was obtained at 270°C with WHSV of 15 h 1.

The adsorption of lead ions on granular activated carbon (GAC) and removal of lead as heavy metal using GAC studied in a reverse fluidized bed. GAC is suitable adsorbent particularly to remove heavy metals from water. A fluidized bed was more suitable technology for GAC, due to its certain advantages over packed bed. The only problem arises in fluidized bed is the low density (0.44 g/cm3) of GAC, which makes it to float onthe liquid surface. A simple concept of reverse fluidized bed can be a better replacement. Experimental investigations were carried out in a reverse fluidized bed. Result for removal efficiency of GAC with change in concentration of solution, change in pH of solution, change in bed height of GAC, change in residence time was investigated. It was observed that % removal of lead increases with an increase in bed height and time, where as it gets decreased with an increase in initial lead concentration and pH of the solution.

The paper examined whether investment serves as a channel through energy could promote economic growth in Nigeria. A model that incorporated energy as a separate input and as an indirect input was developed and estimated. The results showed that the potential of investment to enhance economic growth is significantly depressed by the energy resources dependence. Although pubic investment was found to be a channel through which energy resources enhanced economic growth in Nigeria. There is evidence that Dutch disease/resource curse problem is a Nigerian phenomenon as energy abundance is found to significantly impair economic growth in Nigeria.

In dry thermal oxidation process with Si, the growth rate of the initial parts of the reaction is currently modeled with additional terms; besides the usual linear parabolic was time dependent. However, due to limitation in the process set up, it was found in literature and in patent; these methods did not produce oxides less than 1.5 nm thick, often assumed equal to the native thickness. Attempt made to grow oxides in a furnacewith dry oxygen, including cycles of cleaning and annealing in Ar. The effects limitthe thickness to about 1.5 nm was investigated. These oxides were evaluated for the resulting quality of the interface of the oxides,with low temperature layer-by-layer methods.

Some physical and mechanical property testing of main stalks of Lilium was conducted to provide information for future automatic machine design. Shear, compression and bending properties of Lilium stalks were determined with using a universal testing machine. The experiments were conducted at three rate of loading levels from 30 to 50 mm/min, three knife bevel angle levels from 30 to 60 degree and at two levels the stalk; upper and lower. The results showed that all the mentioned above parameters had significant effect on the measured mechanical properties (P<0.01). In all three loading rate, an increasing the shear strength and specific cutting energy were observed as the knife bevel angle increased. The highest compression strength and specific compressing energy were 6.86 MPa and 21.34 mJ/mm2 at the lower level, while the lowest compression strength and specific compressing energy were 2.90 MPa and 10.69 mJ/mm2 at the upper level. As the loading rate of the stalk increased, the bending strength decreased, indicating a reduction in the brittleness of the stalk. The average values for modulus of elasticity were found to be 23.48 and 15.96 MPa for stalk regions of upper and lower, respectively.

Barium cerate-based perovskite oxides are protonic conductor candidates for intermediate temperature solid oxide fuel cells due to their high ionic conductivity and good sinterability. The aim of the present study is to fabricate a half-cell single-cell includes substrate, anode and electrolyte layers. The exact composition of BaZr0.1Ce0.7Y0.2O3─δ (BZCY7) has been selected as a proton conducting electrolyte. The fabrication process of a dense electrolyte membrane on a NiO- BaZr0.1Ce0.7Y0.2O3─δ (NiO-BZCY7) anode substrate has been studied by a copressing process after co-firing at 1400ºC. BZCY7 powders were synthesized by solid-state reaction method after calcinations at 1150ºC. A single phase was obtained at this low temperature. The phase composition of the resulting specimens was investigated using X-ray diffraction (XRD) analysis. Scanning electron microscope (SEM) was used to evaluate the features of the synthesized powders and also the condition of connected layers in half-cell.

In this article, an indirect forced convection solar dryer is used to study the kinetic drying of eggplant. The effective moisture diffusivity calculated by slop method follows the solar intensity with the maximum value of 1.68 E-09 at 15 PM. Performance of solar dryer is determined by defining the efficiency of collector and an effectiveness factor as the ratio of the drying rate in the indirect solar dryer to the drying rate in the open sun. The collector efficiency and the effectiveness factor vary with the drying time inversely. 2. Hr and is 2 g H2O. g ds. Hr for 1 1 1 1 the open sun drying method in the beginning of the process. Several well-known mathematical models are applied in order to select the best model to present the eggplant drying behavior. Midilli and Kucuck model refers to drying process of product with correlation coefficients (R2) which are 0.9998 for solar dryer and 0.9996 for open sun.

The study attempts at finding the impact of foreign direct investment on carbon dioxide emissions in Pakistan. It takes carbon dioxide emissions as dependent variable and foreign direct investment, share of manufacturing value added and population density as independent variables. ADF, PP, Ng-Perron and Zivot-Andrews Unit root tests were used to find the unit root problem. ARDL and its error correction model were used to find the long run and short run relationships. The study found the long run relationship in the model but short run relationship did not exist. Foreign direct investment, manufacturing value added and population density have positive impact on carbon dioxide emissions.

In this article, nonlinear thermal Analysis of air-heating flat-plate solar collectors was conducted to obtain temperature distribution inside the heat transfer unit. Due to temperature-dependency of specific heat coefficient of air, the governing differential equation had a noticeable nonlinear nature. Therefore, for the solution of nonlinear equation a highly accurate and simple analytical method which is called Differential Transformation Method (DTM) and basic numerical method, Runge-Kutta (RG) was employed. As a significant result, it is depicted that the DTM results have an interesting conformity with numerical ones. After this verification, the effects of physical applicable parameters on temperature distribution, useful gained heat and thermal efficiency of collectors were investigated. It was concluded that increase in dimension of collector maynot increase the efficiency (about 10% decreased). However an increase in the effectiveness coefficient () and air mass flow rate () enhanced the performance of solar collectors and the process efficiency increased up to 12%.

A technique to quantify the leachate pollution potential of solid waste landfills on a comparative scale using an index known as the leachate pollution index (LPI) developed. The LPI is a quantitative tool by which the leachate pollution data of the landfill sites can be reported uniformly. It is an increasing scale index and has been formulated based on Delphi technique. The formulation process involved selecting variables, deriving weights for the selected pollutant variables, formulating their sub-indices curves and finally representing the pollutant variables to arrive at LPI. The aggregation function is one of the most important steps in calculating any environmental index. If aggregation function is ambiguous, the result will raise an unnecessary alarm, indicating a comparatively less polluted environmental situation as mere contaminated. Similarly, if the aggregation function is eclipsed a false sense of security may be created, indicating a highly polluted environmental situation as less polluted. In this paper, the concept of LPI is briefly described. In order to select the most appropriate aggregation function, various possible aggregation functions are described and used to calculate LPI values for pilot scale landfill lysimeter at KUET campus, Khulna, Bangladesh. Based on obtained results, it is concluded that the weighted linear sum aggregation function is the best possible aggregation function for calculating LPI. Sensitivity analysis of the six short-listed aggregation functions is performed to substantiate this conclusion.

The present research study is on development and performance evaluation of a solar thermal collector that warms up air as transferring medium of heat for drying of grains. A 6 meter long, 4 meter wide and 0.3 meter thick solar thermal collector was constructed in which a V-corrugated steel sheet was used as absorber and a 6 mm thick glass used as glazing. The collector body was fabricated from plywood. The solar thermal collector is linked with a 4 meter high grain storage bin having a diameter of 2 meter. Performance of this collector was evaluated from November 2011 to January 2012 at seven different convective flow rates of air (7.5, 14.16, 28.30, 56.6, 112.2, 168.5 and 224.4 kg.h). The statistical analysis showed that increase 1 in mass flow rate significantly (P > 0.003) increases the performance of the solar collector. Also there was decrease in performance by the change of months of year. The efficiency was 10% higher in November 2011 as compared to January 2012. It was concluded that for drying of grains the solar thermal collector must be operated at high mass flow rates of air from 9:00 am to 4:00 pm to get maximum performance from the solar thermal collector used for grain drying.

The effect of irrigation and nitrogen fertilization on the growth characteristics of cocoa (Theobroma cacao L.), specifically the clone CCN-51, was evaluate in a field experiment conducted on the period from August 2010 to June 2011 in Jequié city, Bahia State, Brazil. The experimental area, approximately 0.18 ha with the planting of cocoa clonal CCN- 51 in Yellow Oxisol was irrigated drip emitters. The statistical experimental design was randomized blocks with four replications where the factors water level and nitrogen level were factorial combined resulting in the 16 treatments. During the experimental period were measured plant height in plant height and stem diameter. The biometric variables responded to treatments. The water level used in this study negatively affected the plant growth. The nitrogen level used in this study positively influenced the plant growth. The relative growth rate in relation to the plant height and stem diameter, on average, corresponded to about 14% and 15%, respectively.