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

The aim of this study was to investigate the feasibility of hydrogen production from sugarcane bagasse by supercritical water gasification (SCWG) at low temperature and in presence of alkali catalyst. Experiments were carried out in a batch autoclave reactor at 400 °C and 9% solid content. Effect of reaction time and alkali catalyst on gas yield, gas composition, carbon gasification efficiency (CGE) and hydrogen gasification efficiency (HGE) were investigated. Influence of reaction time on gas yield and composition as well as on CGE was found to be insignificant. Extending the reaction time even up to 4 h could not cause an attractive conversion of bagasse. In the presence of catalysts (K CO, KHCO, NaHCO and NaOH), sugarcane 2 3 3 3 bagasse was partially gasified in SCW and hydrogen-rich gas containing CO as the main carbon compound 2 was produced. Among the implemented catalysts, K CO was identified to be the most effective for 2 3 improvement of HGE. Use of the catalyst under our experimental conditions, the maximum HGE of 19% was achieved; however the highest CGE occurred with KHCO. Results showed that feed to catalyst ratio of 2 was 3 high enough to reach the greatest possible gasification of hydrogen at 400 °C and 45 min. More CGE and HGE would be possible only by increasing the temperature, pressure and/or reaction time.

Gasification offers a combination of flexibility, efficiency and friendliness to the environment that these are important in meeting the energy needs to overcome impurities or contaminants and organic particles, such as tar. In fact tar is a serious problem that must be considered in the process of gasification, especially for an internal combustion engine application. Gas cleaning system is one the methods to reduce the tar produced in gasification process. This study aims to evaluate the content of tar before and after the ventury scrubber. Gasification air flow rate was 189.6 lpm; the water flow rates through the venturi scrubber were in the range of 10 to 30 lpm. The tar contents of the produced gas before and after cleaning were 675 and 125 mg/m3, respectively.

Energy is considered as an important production factor in many systems and therefore should be managed in parallel with other main production resources including land, labor and capital. In this paper, the energy efficiency scores of some selected dairy farms, using the non-parametric data envelopment analysis approach was assessed. The results for efficient farmers based on two DEA models showed that with an energy conservation policy, farmers can perform better in stock farming. The total energy consumption was 72.8 GJ/cow and the top two energy consuming inputs as feed intake and electricity drew the fact that promoting input utilization efficiency seems critical. The mean technical efficiency score of 0.88 made this ample need more apparent. Machinery, electricity and feed were suggested as the main inputs for optimization due to their high contribution in energy saving (46 and 36%, respectively). The least amount of ESTR (Energy Saving Target Ratio) for human labor indicated that it is employed efficiently. By practicing efficiently, dairy farmers are potentially capable of reducing their energy consumption by 16.8%. In this study, adopting new methodologies, cutting the excess use of inputs such as feed stuffs through using standard feeding rations and providing consultancy and extension programs are recommended.

Decline in crop yield has been a problem in Northern Brazil region due to inherent low fertility status of the soils and water deficit of different crops. In order to study the effects of nitrogen and available soil water levels on growth and yield components of sunflower, an experiment was carried out from March to June 2010 in a semi-controlled greenhouse condition of the Federal University of Campina Grande, Paraiba, Brazil using Alfisol soil. The treatments were arranged as a completely randomized design, in a 4×4 factorial experiment (four nitrogen levels and four available soil water levels), in triplicates, total of 48 experimental units. The nitrogen levels in kg/ha were 0; 60; 80 and 100 which was added as urea; the available soil water levels were 55; 70; 85 and 100%. The results of this research indicate that nitrogen had a significant effect only on leaf area at 40 DAS and % achenes viable. The effect of available soil water on sunflower cv. Embrapa 122/V-2000 biometry and the yield showed that there were significant differences, on average, in all growth traits (stem height and diameter) at 40 and 60 DAS, in leaf number at 40 DAS, in leaf area at 40 and 60 DAS and in all production traits. The biometry and yield response to available soil water of different crops is of major importance in production planning. In this study, the maximum biometry and yield response factor of sunflower was determined at 100 % of available soil water.

In view of ever increasing global demand for energy, there has been substantial interest in developing renewable biologically produced fuel. Microalgae are one such emerging resource considered as an alternative for biodiesel production. However its realistic potential is often either over estimated or underestimated. In view of this, a rigorous assessment is carried out to evaluate the realistic potential of micro algal biodiesel based on photosynthesis, thermodynamics and physical assumptions. This paper identifies six best regions in each continent for algal biomass cultivation considering both sunlight and local climatic conditions. The mean hourly meteorological data, sunlight, ambient temperature and rainfall information for the identified potential site is combined to estimate annual biomass production, lipid production and carbon mitigation potential. Maximum possible algal biomass yield and oil productivity have been estimated for six global sites at three different scenarios of photosynthetic efficiency 11.42, 6 and 3%. The upper optimistic biomass, oil yield and carbon fixation potential was calculated to be 533 T/ha/yr, 1, 25, 333 L/ha/yr. and 95 Tons CO /ha/yr. This study 2 provides a baseline data for theoretical maximum, minimum and best estimates of open pond microalgae production systems.

In this paper, application of computational fluid dynamics simulation of the cooking process of bread and energy saving inside an oven is presented. A two dimensional CFD model is applied to investigate the hot air distribution and bread cooking conditions inside the stove. Results are shown as velocity contours, turbulence intensity, static temperature and pressure distribution. It was found that the turbulence intensity was the highest at part of the stove, which means which part of bread would cook the fastest as it receives larger quantity of energy compared to other parts. The arrangement of the stove is discussed and some improvement offered to find a desire temperature distribution that leads to a suitable cooking process. In addition, the current results can be useful for next improvements on the existing stove for energy saving.

This review deals with field studies of particles indoors and exposure to particulate concentrations on recent surveys of homes. The results of indoor and personal exposure concentrations are presented. In addition the effect of other related air pollution factors which might have an effect on exposure to particles are discussed. This paper surveys of particle concentrations and sources in homes from 198 to 2011. Three major studies which in the USA and a large scale study in Europe that carried out to measure personal exposure and indoor home particle concentrations. A number of small personal exposure studies in homes are also briefly summarized. Personal exposure studies in the USA, EXPOLIS cities and Toronto and others similar studies have documented that the personal exposure to PM concentrations was higher than those measured indoors. Most 2.5 of these studies found a suitable relationship between residential indoor and personal exposure to particulate matter. Personal exposure to respirable particulate matter highly correlated with indoor air. Ambient concentrations obtained from Fixed Site Monitors poorly correlated with total personal exposure to particulate matter concentrations. Some indoor particle source such as smoking, cooking and resuspension of indoor dust may increase subjected to personal exposure and indoor particulate concentrations.

Alzheimer's disease (AD) is characterized by impaired glucose metabolism and can be detected using Positron Emission Tomography (PET) neuroimaging. In this study, an automatic method for diagnosis of AD based on region of interest (ROI) is presented. First, subject’s PET neuroimage is automatically parcellated into 48 predefined ROIs using Harvard-Oxford structural Atlas. The most discriminative regions are discovered using principal component analysis (PCA). Based on features extracted using PCA, support vector machines are adapted to discriminate normal control (NC) from AD. For classification of AD from NC, the proposed method achieves 89.14% of classification accuracy; while the accuracy of Automated Anatomical Labeling (AAL)-based approach is only 80.68%.

In this paper, the peak ground acceleration (PGA) over the bedrock is calculated by a probabilistic and deterministic seismic hazard assessment. An active fault map of the region is prepared. For this purpose, all active faults in a radius of 100 km from Amol city center are recognized and their seismic and rapture parameters are determined. Afterwards, for seismic hazard analysis, the seismic parameters of study region are determined and seismic classification zone is performed. Maximum earthquake, seismic parameters and also occurrence rate are determined. Seismic hazard analysis is performed using 3 different attenuation relationships resulted in seismic hazard curves for Amol city center. The peak ground acceleration (PGA) for design levels MCE, OBE and benefit life structure 50 and 100 years are presented. For the PGA quantity design levels operating base earthquake (OBE), maximum credible earthquake (MCE) for horizontal and vertical dimensions were equal to sequences of 0.33, 0.5 and 0.3, 0.53 g, respectively.

The infrared and electronic absorption spectra of a series of new heteroleptic chelated copper (II) complexes [Cu(diamine)(acac)]X that encompass N,N'-1,6-bis(2-bromophenyl)-2,5 diazahexane (diamine), acetylacetonate (acac) and ClO, BPh, PF and BF (X) were studied. The IR, electronic absorption spectra and 4 4 6 4 - - - - the molar conductivity of the newly prepared complexes were presented and discussed. The molar conductivity in dichloromethane reveals a predominance of electrostatic interactions between [C (diamine)(acac)]+ entity and anions, X- that counterbalance the positive charge. The resulting complexes with local symmetry of CuO N 2 2 attain a square-coplanar structure and exhibit the tendency for axial ligation, which is enhanced when an electron-attracting substituent is attached to the phenyl ring of diamine moiety. The tendency for axial ligation is particularly fulfilled when suitable nucleophiles (solvents) with different donor abilities exist, leading to solvatochromism. The solute-solvent interactions are revealed by shifts in the ligand field absorption spectra that are enhanced as the donor power of the solvent increases. Linear dependence of the ligand field absorption maximum on solvent donor number is generally observed.

An important part of maintaining a solid waste landfill is managing the leachate through proper treatment to prevent pollution into the surrounding ground and surface water. Any assessment of potential impact of a landfill on groundwater quality requires consideration of the component of leachate most likely to cause an envionental impact as well as the source of concentration of those components. Leachate pollution index (LPI) is an environmental index used to quantify and compare the leachate contamination potential of solid waste landfill. This index is based on concentration of 18 pollutants in leachate and their corresponding significance. That means, for calculating the LPI of a landfill, concentration of these 18 parameters are to be known. However, sometimes the data for all the 18 pollutants included in the LPI may not be available to calculate the LPI. In this study, the possible errors involved in calculating the LPI due to nonavailability of data are reported by the author. The leachate characteristic data for solid waste landfill at Chittagong in Bangladesh have been used to estimate these errors. Based on this study, it can be concluded that the errors may be high if the data for the pollutants having significantly high or low concentration are not available. However, LPI can be reported with a marginal error if the concentrations of the nonavailable pollutants are not completely biased.

The sesame seeds were mechanically cold pressed at temperature below 45°C then centrifuged. No chemicals were used. The temperature during centrifugation of sesame paste was recorded. Temperatures in less than one hour operation has elevated to 148, 273 and 315°C in 1200, 1800 and 2400 G-force centrifugal acceleration, respectively. Since the centrifugal accelerations during the process cut at 1200, 1800 and 2400 G-force at about 35, 20 and 10 minutes, respectively. The maximum allowable temperatures raised to about 100°C. Linear and quadratics regression model were fitted to data.

Semiconductor materials with coatings have a wide range of applications in MEMS and NEMS. This work uses transfer-matrix method for calculating the radiative properties. Dopped silicon is used and the coherent formulation is applied. The Drude model for the optical constants of doped silicon is employed. Results showed that for the visible wavelengths, more emittance occurs in high concentrations and the reflectance decreases as the concentration increases. In these wavelengths, transmittance is negligible. Donars and acceptors act similar in visible wavelengths. The effect of wave interference can be understood by plotting the spectral properties such as reflectance or transmittance of a thin dielectric film versus the film thickness and analyzing the oscillations of properties due to constructive and destructive interferences. But this effect has not been shown at visible wavelengths. At room temperature, the scattering process is dominated by lattice scattering for lightly doped silicon and the impurity scattering becomes important for heavily doped silicon when the dopant concentration exceeds 1018cm-3.