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31.
T. Amani Ph.D. M. Nosrati Ph.D. S. M. Mousavi Ph.D. R. K. Kermanshahi Ph.D. 《International Journal of Environmental Science and Technology》2011,8(1):83-96
Volatile fatty acids are the most important intermediates in anaerobic digestion, and their degradations are extremely complicated thermodynamically. In this research, syntrophic anaerobic digestion of volatile fatty acids using enriched acetogenic and methanogenic cultures in a batch reactor at mesophilic conditions was investigated. Interactive effects of key microbiological and operating variables (propionic, butyric and acetic acids, retention time and methanogen to acetogen populations ratio) on the anaerobic degradation of volatile fatty acids were analyzed. Acetogenic and methanogenic anaerobes in the granular sludge from an up-flow anaerobic sludge blanket reactor were enriched at mesophilic conditions within a period of four weeks, separately. Enriched cultures were mixed with known proportions and then used in the bioreactor. Experiments were carried out based on central composite design and analyzed using response surface methodology. Four parameters (final concentrations of propionic, butyric and acetic acids and biogas production) were directly measured as response. Also, the optimum conditions for volatile fatty acid degradation were found to be 937.5 mg/L, 3275.5 mg/L, 2319.5 mg/L, 45 h and 2.2 proportions for propionic acid, butyric acid, acetic acid, retention time and methanogen to acetogen populations ratio, respectively (corresponding to maximum volatile fatty acid removal efficiencies and biogas production). The results of the verification experiment and the predicted values from the fitted correlations at the optimum conditions were in close agreement at a 95% confidence interval. The present study provides valuable information about the interrelations of quality and process parameters at different values of microbiological and operating variables. 相似文献
32.
An appropriate multiple criteria decision making method for solving electricity planning problems, addressing sustainability issue 总被引：1，自引：1，他引：0
N. Bagheri Moghaddam M. Nasiri S. M. Mousavi 《International Journal of Environmental Science and Technology》2011,8(3):605-620
In the past, decision making within the energy sector, especially in Iran, was limited to economic analysis. Lately, multiple criteria decision making has gained great popularity. However, this is not enough to make a right decision by considering sustainability. This paper deals with designing an appropriate multiple criteria decision making method to address the multifaceted nature of such problems. This task is the second precondition to make a decision which meets the sustainability criterion. This is done by revealing new facts about quantitative and qualitative data and the degree of compensation between the criteria. Moreover, this paper illustrates the capability of different methods with regard to sustainable energy planning and management in two steps: 1) comparison of two main approaches in the strategic energy planning context; 2) evaluation of multi attribute decision making methods and combining them. Combining four methods including Analytical hierarchy process, Preference ranking organization method for enrichment evaluation II, geometric mean and weighted sum seems to result in designing an appropriate method which meets the sustainability criterion. These contributions are proposed for comparing the renewable energy technologies with non-renewable ones. Nevertheless, these seem to be applicable in any comparison between discrete alternatives in the energy sector. 相似文献
33.
Global warming and hurricanes: the potential impact of hurricane intensification and sea level rise on coastal flooding 总被引：3，自引：1，他引：2
Mir Emad Mousavi Jennifer L. Irish Ashley E. Frey Francisco Olivera Billy L. Edge 《Climatic change》2011,104(3-4):575-597
Tens of millions of people around the world are already exposed to coastal flooding from tropical cyclones. Global warming has the potential to increase hurricane flooding, both by hurricane intensification and by sea level rise. In this paper, the impact of hurricane intensification and sea level rise are evaluated using hydrodynamic surge models and by considering the future climate projections of the Intergovernmental Panel on Climate Change. For the Corpus Christi, Texas, United States study region, mean projections indicate hurricane flood elevation (meteorologically generated storm surge plus sea level rise) will, on average, rise by 0.3 m by the 2030s and by 0.8 m by the 2080s. For catastrophic-type hurricane surge events, flood elevations are projected to rise by as much as 0.5 m and 1.8 m by the 2030s and 2080s, respectively. 相似文献
34.
The authors would like to thank the discusser for his considerations and comments. The discusser believes that some of the derived formulations need to be referred to his previously published works and also some related studies have not been cited. 相似文献
35.
S. Jamshid Mousavi Hosein Alizadeh Kumaraswamy Ponnambalam 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(8):2051-2061
Stochastic optimization methods are used for optimal design and operation of surface water reservoir systems under uncertainty. Chance-constrained (CC) optimization with linear decision rules (LDRs) is an old approach for determining the minimum reservoir capacity required to meet a specific yield at a target level of reliability. However, this approach has been found to overestimate the reservoir capacity. In this paper, we propose the reason for this overestimation to be the fact that the reliability constraints considered in standard CC LDR models do not have the same meaning as in other models such as reservoir operation simulation models. The simulation models have fulfilled a target reliability level in an average sense (i.e., annually), whereas the standard CC LDR models have met the target reliability level every season of the year. Mixed integer nonlinear programs are presented to clarify the distinction between the two types of reliability constraints and demonstrate that the use of seasonal reliability constraints, rather than an average reliability constraint, leads to 80–150 % and 0–32 % excess capacity for SQ-type and S-type CC LDR models, respectively. Additionally, a modified CC LDR model with an average reliability constraint is proposed to overcome the reservoir capacity overestimation problem. In the second stage, we evaluate different operating policies and show that for the seasonal (average) reliability constraints, open-loop, S-type, standard operating policy, SQ-type, and general SQ-type policies compared to a model not using any operation rule lead to 190–460 % (200–550 %), 100–200 % (80–300 %), 0–90 % (0–60 %), 30–90 % (0–20 %), and 10–90 % (0–10 %) excess capacity, respectively. 相似文献
36.
M. Mousavi Ph.D. A. Taymouri V. Ghaffavian 《International Journal of Environmental Science and Technology》2009,6(3):499-508
In this paper, modeling and simulation of combustion process for polybrominated diphenyl ethers in rotary kilns has been investigated. Proper formula is found for the solid wastes which contain polybrominated diphenyl ethers and then combustion process is simulated by considering possible reactions, appropriate dimensions and operating conditions for rotary kiln and necessary relations for reaction rates. The software of MATLAB is used for the simulation. The mass variations for solid waste, outlet gas and its components are calculated during 20 h. The results show that the reaction rate is high for the first 2 h, thus the value of solid waste and oxygen decrease quickly while value of produced gases increases. The mass increase of polychlorinated dibenzo-p-dioxins/furans and polybrominated dibenzo-p-dioxins/furans during the whole time of the process is linear with mild slope but for the other compounds, including steam, carbon dioxide, nitrogen, nitrogen oxide, sulphur dioxide, hydrogen chloride and hydrogen bromine, the slope of variations becomes mild after 3 h. The process becomes steady state almost after 9 h. 相似文献
37.
Mohammad Ethteram Sayed-Farhad Mousavi Hojat Karami Saeed Farzin Ravinesh Deo Faridah Binti Othman Kwok-wing Chau Saeed Sarkamaryan Vijay P. Singh Ahmed El-Shafie 《Environmental Earth Sciences》2018,77(13):510
Optimizing reservoir operation rule is considered as a complex engineering problem which requires an efficient algorithm to solve. During the past decade, several optimization algorithms have been applied to solve complex engineering problems, which water resource decision-makers can employ to optimize reservoir operation. This study investigates one of the new optimization algorithms, namely, Bat Algorithm (BA). The BA is incorporated with different rule curves, including first-, second-, and third-order rule curves. Two case studies, Aydoughmoush dam and Karoun 4 dam in Iran, are considered to evaluate the performance of the algorithm. The main purpose of the Aydoughmoush dam is to supply water for irrigation. Hence, the objective function for the optimization model is to minimize irrigation deficit. On the other hand, Karoun 4 dam is designed for hydropower generation. Three different evaluation indices, namely, reliability, resilience, and vulnerability were considered to examine the performance of the algorithm. Results showed that the bat algorithm with third-order rule curve converged to the minimum objective function for both case studies and achieved the highest values of reliability index and resiliency index and the lowest value of the vulnerability index. Hence, the bat algorithm with third-order rule curve can be considered as an appropriate optimization model for reservoir operation. 相似文献
38.
A limiting factor in developing artificial recharge of groundwater is clogging of the soil surface and consequent reduction
of infiltration rates. In order to evaluate the degree of improving infiltration rates by scraping away various amounts of
the upper soil materials, a study was conducted at three artificial recharge sites (Kohrouyeh, Bagh-Sorkh, and Kachak) in
Isfahan Province, central Iran. Five treatments (T1–T5) were considered. Infiltration was measured: T1, on deposited sediment
layer; T2, after removing the sediments; T3, scraping of sediments and 5 cm of soil; T4, scraping of sediments and 10 cm of
soil; and T5, removing sediments and 15 cm of soil. Initial soil-moisture content of the sites ranged from 1.0–2.87% for Kohrouyeh,
1.18–3.47% for Bagh-Sorkh, and 1.89–3.93% for Kachak. The main texture of the soils was sandy loam. Clay particles have penetrated
to a depth of more than 40 cm in some of the recharge basins. A significant increase in final infiltration rate of T5 as compared
to T1 treatment was observed for all recharge sites. The final infiltration rates of T1 and T5 treatments for Kohrouyeh, Bagh-Sorkh,
and Kachak sites were 0.35, 7.9; 1.22, 12.3; and 0.93, 6.2 cm/h, respectively. The differences between infiltration rates
of T2, T3, and T4 treatments were not statistically significant. It is concluded that on average, the infiltration capacity
of the untreated recharge facilities have reached 20.3% of the original values, and that scraping the top sediment layer and
15 cm of topsoil could restore 68.3% of the initial infiltration capacity.
Received, July 1998 / Revised, April 1999, May 1999 / Accepted, June 1999 相似文献
39.
A feature weighting and selection method for improving the homogeneity of regions in regionalization of watersheds 
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下载免费PDF全文 The method used for feature selection or feature weighting in regionalization of watersheds may affect the results of regionalization methods considerably. It can play a key role in forming hydrologically homogeneous regions for regional flood frequency analysis. In this study, a method based on exploring the nearest and farthest neighbours of data points is introduced for identifying salient features for regionalization of watersheds. The method includes options to relate watershed features to flood data records in order to increase the homogeneity of the regions. The nearest and farthest neighbours are identified based on the criteria such as the mutual information criterion and Spearman's rank correlation coefficient. Then, the watershed features more able to explain the relationships between the nearest and farthest neighbours are identified as salient features to form homogeneous features for regional flood frequency analysis. The results show that the optimum option of the proposed method improves the performances of the hard and fuzzy clustering algorithms in more than half of the cases based on the cluster validity indices. Furthermore, the results reveal that the optimum option can increase the number of the homogeneous regions formed by clustering algorithms to a great extent. By using the optimum option with 5 nearest and 5 farthest neighbours, longitude, drainage area, and run‐off coefficient are identified as the salient features to regionalize Sefidrud basin. The results show that the proposed method can be considered as an efficient method to form homogeneous regions for regional flood frequency analysis. 相似文献
40.
Slope stability analysis of soil with a weak layer sandwiched between two strong layers is considered as a complex geotechnical problem. In this problem, the objective function is non‐convex and discontinuous with the presence of multiple strong local minima. Classical optimization techniques fail to converge to a valid solution unless a proper initial trial is adopted. Even though many new optimization algorithms have emerged, they have not been applied to geotechnical problems yet. In the present study, some recent swarm intelligence algorithms are adopted for some complicated example of slope stability problems and benchmarked with the traditional particle swarm optimization algorithm. From the results, it seems the levy flight krill herd algorithm is the most efficient method over proposed algorithms for this kind of problem. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献