Background and Objective: The concentration of nitrate, factors affecting the balance sheet, and the changes in an aquifer is of utmost importance. Because modeling is an efficient method to predict the concentration of ions in water resources, in this study using Lumped-parameter model and Monte Carlo simulation model, the nitrate concentrations in groundwater resources of Qazvin Plain were estimated and analyzed.Materials and Methods: A total of 19 wells in different climates of saline watershed in Qazvin Plain were selected and entry and exit routes of nitrate to these sources were analyzed using Lumped-parameter model. Finally, Monte Carlo simulation was used to determine the probability of the estimated nitrate concentration in aquifer.Results: Application of Lumped-parameter model for a part of a part of groundwater resources in Qazvin Plain watershed predicted the nitrate concentration in the range of 8.12 to 15.94 mg/l. The maximum concentration was estimated in cold-dry climate with 12.8±0.04 mg/L.Moreover, it was found that the difference between the estimated nitrate concentration and factors affecting its concentration in different climates was significant (p<0.05).Conclusion: Despite the predicted concentrations of nitrate in the study area were in accordance with the Iran national standard for drinking purposes, the cumulative probability of Monte Carlo simulation showed that the possible violation of nitrate from the safe limit of 10 mg/l in the study area is 90% (p=0.005).

Background and Objective: Numerical modeling of biological structures would be very helpful tool to analyze hundreds of human body phenomena and also diseases diagnosis. One physiologic phenomenon is blood circulatory system and heart hemodynamic performance that can be simulated by utilizing Lumped method. In this study, we can predict hemodynamic behavior of one artery of circulatory system (anterior cerebral artery) when disease such as internal carotid artery occlusion is occurred.Method: Pressure-flow simulation is one the leading common approaches for modeling of circulatory system behavior and forecasts of hemodynamic in numerous physiological conditions. In this paper, by using Lumped model (electrical analogy), CV system is simulated in MATLAB software (SIMULINK environment).Results: The performance of healthy blood circulation and heart is modeled and the obtained results used for further analyses. The stenosis of internal carotid artery at different rates was, then, induced in the circuit and the effects are studied. In stenosis cases, the effects of internal carotid artery occlusion on left anterior cerebral artery pressure waveform are investigated.Conclusion: The findings of this study may have implications not only for understanding the behavior of human biological system at healthy condition but also for diagnosis of diseases in circulatory and cardiovascular system of human body.

In this study a new minimum Lumped electrical model of total circulatory system through numerical solutions to approximate the response of the human circulatory system was presented. Among five existent ventricular elastances as activity function of heart pumps, a more accurate model was chosen as well as the operation of baroreflex system to accommodate variations in heart rate and systemic vascular resistance of a native human circulatory system. The model with extracting the hemodynamic reaction of a patient with heart failure has the ability to study completely the influence of left heart failure on the right ventricle performance. The model can be used to analyze the variations of pressure-volume loop curve for normal hearts and dilated and hypertrophic heart failure patients at rest. The simulation results, in comparison with the clinical data, showed that the model could efficiently simulate the progressed states of heart failure with an acceptable accuracy and among all studied states of disease, hypertrophic LS and RSHF state caused to make critical conditions for the simulated patient.

One of the most important factors in reducing the lifetime of PEM fuel cells is heterogeneous current distribution on membrane surface. Since flow field plays an important role in reactants distribution and water depletion and consequently current distribution, hence, in this paper, with development of a Lumped model, water and current distributions on membrane surface were evaluated in two different designs. In this model, the flow field is divided into equal segments and connection between segments are created through flow field pattern. In both designs, flow field of anode side was serpentine, but on cathode side, parallel and serpentine flow field were used in first and second design, respectively. Simulations were carried out for different input relative humidity from 0 to 100 in both sides. The results showed that flow field had no significant effect on polarization curve and the second design had a little better performance in high current density. Also, in terms of current distribution, the second design shows a better uniformity, so that in the first design in fully saturated inlet condition, difference between the percentage of current generated between the first and last segments is about 1.57 percent which recehes to 1.45 percent in the second case.

This paper focuses on the development of a complete model of the Timoshenko beam, based on considering the effects of shear deformation. A method based on distributed-Lumped modeling approach is proposed to solve the governing equations. Natural frequencies obtained by this method are compared and verified with Chebyshev pseudo spectral method. The effects of shear deformation on natural frequency of pinned and clamped beams are discussed for various diameters. In addition, the effects of Lumped mass and its position are investigated for clamped and pinned rotors with different diameters. It is shown that, while the new method leads to highly accurate results, its simplicity and accuracy makes it appropriate for application on industrial systems.

The paper discusses the theory of critical strain energy levels for structures with Lumped parameters. The theoretical assumptions and profs for common case are presented. The idea of external actions and strain energy field separation leads to the minimum strain energy principle. It has the self-stress of the structure physical sense. In the general case, a structure's extremal values of parameters are determined from an eigenvalue problem. The critical levels criterion means the self-stress state change. The strain energy consists of two parts: strain energy, which equilibrates the action work, and residual strain energy, which does not allow a deformable body to collapse. This allows for the total and residual strain energy to be calculated. The traditional problem formulation does not give us that option. The proposed theory is illustrated on a rod system, which explains the change in the self-stress state of the structure in a simple manner. The static matrix and stiffness matrix are obtained for the three-bar structure. The eigenvalue problem allows us to obtain the principal values of the nodal reactions and displacements of the structure. New formulations of structural design and structural analysis tasks are given. The results are compared with classical methods of solution. The formulations of weak link problems and progressive limit state problems are given. A structure's residual load capacity is evaluated by the residual strain energy.

Conjunctive use of surface and groundwater resources is a preferred approach in water resources management. Compared to dam construction, groundwater has certain advantages, among which are less costs, less sedimentation and evaporation, fewer water quality problems, and less social and cultural problems. To reduce the major problems associated with the development of large-scale surface impoundment systems, cyclic storage systems can be used as an alternative. A cyclic storage system (CYCS) is an integrated interactive system consisting of two subsystems of surface water storage (reservoir) and groundwater; this system together with artificial recharge is able to satisfy the predefined demands with rather high reliability. In order to optimize these systems, one must consider the hydraulic interactions between all the components, but unfortunately it has been neglected in many studies. In this article, a nonlinear optimization model for design and operation of cyclic storage systems has been developed using the Lumped approach. In order to evaluate the model, its results have been compared with the results of a model in which distributed approach had been deployed, and so the efficiency of Lumped models to solve the problems of cyclic storage systems has been investigated.

Flood routing is one of the complicated subjects in hydraulic engineering. Several methods have been developed for flood routing. These methods can be classified into two different groups, distributed and Lumped routing methods. The main objective of this research is to search for the capabilities of the Artificial Neural Network (ANN) method for flood routing and to introduce a new method based on ANN that can be more accurate than the conventional Lumped routing methods. After utilization of different ANN structures and analysing different data, it was found that a 3-layer perceptron ANN (2 cells in the hidden layer) with sigmoid activation function and bias term in the cells can give good results. Comparison of the ANN results with those of the linear Muskingum method shows that, despite the weakness of the ANN method in exactly satisfying the mass balance equation, it performs better in term of other error criteria such as the sum of square of errors or the error in predicting the time and magnitude of the peak discharge. Another advantage of the ANN method is its capability of interpolating flood wave characteristics. This capability is highlighted in this paper.