Search

In this work, an anisotropic constitutive model for equilibrium swelling of cellulose-reinforced salt-sensitive hydrogels is proposed and its capability is verified using the experimental data. This model is able to predict the swelling behavior of salt-sensitive hydrogels reinforced with fibers in different types of orientation such as perfectly aligned, uniform in-plane, and uniform volumetric. The model is implemented numerically in the finite element method framework. Several related parameters i.e., swelling ratio, principal stretches, true concentration of counter-ion and co-ion, and salt concentration are investigated both analytically and through finite element method (FEM). Good agreement between the analytical and numerical results indicates that the model can be used for simulating more complex structures including multi-layer strips and sheets. The results show that adding cellulose fibers to the hydrogel's medium leads to a significant enhancement in the strength of the material while preserving the inherent flexibility of the hydrogel. [ABSTRACT FROM AUTHOR]

At present, wastewater reuse and recycling in water-stressed countries such as Iran has become a vital option for better management of water scarcity. However, despite the benefits of wastewater reuse, there is a probability of incomplete treatment of wastewater in accordance with the standards. Risk assessment of a wastewater treatment plant is required in order to determine the causes and consequences of failure in the treatment system. Among various methods used for risk assessment, the bow-tie (BT) approach is an efficient technique since it represents a failure event from causes to effects. In this method, for a wastewater treatment plant (WWTP), causes of an adverse event, including the violation of the effluent water quality from the standard limit is studied using fault tree analysis (FTA). Then, the impacts of these adverse events are classified in different scenarios by the use of event tree analysis (ETA). In this study, the BT technique was applied to assess the risk of the WWTP of the Moorchekhort industrial complex (MIC), located in the central part of Iran. The plant consists of two parts, including activated sludge and advanced treatment processes to provide reclaimed water for different industrial uses. Results showed a 41% risk of violation from the effluent standard limit in the MIC WWTP. In addition, analyzing the risk factors revealed that the human error had the largest contribution to the risk calculation of the WWTP failure. In this regard, a number of mitigation measures were proposed to improve the reliability of the WWTP. [ABSTRACT FROM AUTHOR]

Disparity in water supply and demand often leads to conflicts among users over water resources in basins. Game theory is a new tool recently employed for resolving such conflicts. The present study uses non-cooperative games to resolve the conflicts in the Zayandehroud basin. The games are simulated between two stakeholders by the graph model conflict resolution (GMCR) method as one of the non-cooperative methods. The stakeholders are Isfahan Regional Water Company (IRWC) and Agriculture-Jahad Organization (AJO). Stakeholders can execute some strategies competitively, which include A: developing farming lands, B: improving irrigation efficiency, C: controlling withdrawals from aquifers, and D: selling water to the industrial sector. A and B are executed by AJO and C and D are executed by IRWC. The sustainable water allocation scenarios are obtained by GMCR and employed in a water evaluation and planning simulation model to supply consumers' water demand. The best sustainable scenario selected based on GMCR concepts requires irrigation efficiency of agricultural lands to be improved in order to achieve a demand meeting index of 90% and, in contrast, there will be not control on water withdrawal from aquifers. [ABSTRACT FROM AUTHOR]

Zayandehroud River Basin has been experiencing a rapid industrial and agricultural development which caused severe water crisis with several environmental and social consequences. This study presents a dynamic model to analyse the interaction of groundwater and surface water resources in the basin by applying various conjunctive management scenarios. Different scenarios for the management of the Zayandehroud River Basin under the conjunctive use of surface and groundwater resources were evaluated. The water evaluation and planning (WEAP) and the MODFLOW models were used as the planning tool to assess the status of the basin under the designed scenarios and to simulate groundwater resources considering dynamic link between them. The proposed scenarios were based on a demand and supply management approach and accommodate changes in consumption patterns and irrigation efficiency. Finally, the designed scenarios were evaluated based on economic, social, and environmental criteria using the multi-criteria decision-making (MCDM) method. Our analysis indicated that under proper management policies the aquifer withdrawal would reduce from 74% to 62% leading to enhancement of basin sustainability. [ABSTRACT FROM AUTHOR]

In this paper, cooperative game theory (CGT) approaches are used for water allocation in a river basin considering equity benefit shares among stakeholders. An optimization model is initially developed for allocating water to competing users including agricultural, industrial, and environmental users based on both economic objectives. The model is implemented to determine water shares for different likely coalitions among water users. Then, CGT approaches such as Shapely, Nucleolus, and Nash-Harsanyi are used for reallocating net profits to the users as an attempt to encourage them to participate in equitable cooperation. Finally, the results of different game theoretic approaches are evaluated using the stability index and voting methods such as social choice and fallback bargaining. The proposed methodology is applied to the Zayandehrood River basin located in central part of Iran which struggles with water scarcity. The different CGT approaches applied to two predefined real-life scenarios in the basin under study and their performance were evaluated. The results indicate the proper performance of both Nash-Harsanyi and Shapely methods for pessimist and optimistic scenarios, respectively. It is also found that application of the proposed methodology effectively increases the users’ benefits in the study region through optimal water allocation and reallocation of benefits. [ABSTRACT FROM PUBLISHER]