Bayesian Saltwater Intrusion Prediction and Remediation Design under Uncertainty

Groundwater resources are vital for sustainable economic and demographic developments. Reliable prediction of groundwater head and contaminant transport is necessary for sustainable management of the groundwater resources. However, the groundwater simulation models are subjected to uncertainty in their predictions. The goals of this research are to: (1) quantify the uncertainty in the groundwater model predictions and (2) investigate the impact of the quantified uncertainty on the aquifer remediation designs. To pursue the first goal, this study generalizes the Bayesian model averaging (BMA) method and introduces the hierarchical Bayesian model averaging (HBMA) method that segregates and prioritizes sources of uncertainty in a hierarchical structure and conduct BMA for saltwater intrusion prediction. A BMA tree of models is developed to understand the impact of individual sources of uncertainty and uncertainty propagation on model predictions. The uncertainty analysis using HBMA leads to finding the best modeling proposition and to calculating the relative and absolute model weights. To pursue the second goal of the study, the chance-constrained (CC) programming is proposed to deal with the uncertainty in the remediation design. Prior studies of CC programming for the groundwater remediation designs are limited to considering parameter estimation uncertainty. This study combines the CC programming with the BMA and HBMA methods and proposes the BMA-CC framework and the HBMA-CC framework to also include the model structure uncertainty in the CC programming. The results show that the prediction variances from the parameter estimation uncertainty are much smaller than those from the model structure uncertainty. Ignoring the model structure uncertainty in the remediation design may lead to overestimating the design reliability, which can cause design failure

Heat and mass transfer from jet impingement flow for drying machines

Multiple impinging jets are widely used for their enhanced heat and mass transfer characteristics, especially for drying of material such as paper and textiles. Efficient transport characteristics between a drying medium and the material being dried as well as the jet impingement force acting on the force sensitive products (i.e. paper, fabrics) or force sensitive surfaces (i.e. painted, coated) are very critical in the industrial drying applications for the overall performance of the operation. Many variables and influencing factors and parameters need to be considered for the proper design of such multiple impinging jet systems. At present, a complete understanding of the effect of all the design and operating parameters is lacking. Designers should optimize the design parameters of industrial drying equipment to achieve the minimum capital costs (size of the apparatus) and running costs (energy consumption). In the framework of this thesis, the heat and mass transfer rates and pressure force between the multiple impinging round jets and moving surface are investigated numerically. Numerical simulations have been conducted to characterize the impinging jet heat and mass transfer and pressure force on a moving surface with an array of impinging round jets varying the following parameters: jet Reynolds number, nozzle-to-surface distance, jet-to-jet spacing, jet exit angle, relative surface curvature and relative surface velocity. Then, the key controlling design variables such as the nozzle-to-surface distance and the jet-to-jet spacing both normalized by the jet exit diameter (i.e., H/d and S/d), the jet exit velocity, the surface velocity and the jet exit angle have been considered for a design optimization. Correlations describing the average Nusselt number and pressure force coefficient for single row jet configurations impinging on the flat and curved surfaces have been developed. The present work illustrates that it is possible to address the effects of the complex flow phenomena as encountered in industrial drying process using generic CFD codes with good results. Thus complex and extensive computations based on elaborate and time consuming turbulence modelling (i.e. RSM or LES) may be avoided as well the expensive measurements of jet arrays impinging on moving surfaces. Using the correlation equations derived from the computations the dependencies for the main parameters over a wide range may be easily be determined. The analysis of the flow fields showed many different phenomena interacting, leading to different flow regimes. In order to assess these phenomena further investigations, preferably based on LES and DNS modelling and flow measurements are needed. Keywords: Multiple jets, Heat transfer, Pressure force, Energy consumption, Surface motion, Surface curvature, Optimizatio

Multi-objective optimization of drying energy consumption and jet impingement force on a moving curfed surface

For the optimization of the impinging round jet, the pressure force coefficient and drying energy consumption on the moving curved surface are set as the objective functions to be minimized simultaneously. SHERPA search algorithm is used to search for the optimal point from multiple objective tradeoff study (Pareto Front) method. It is found that the pressure force coefficient on the impingement surface is highly dependent on the jet to surface distance and jet angle, while the drying energy consumption is highly dependent on the jet to jet spacing. Generally, the best design study during the multi-objective optimization is found at the maximum jet to surface distance, jet to jet spacing and surface velocity, and also minimum inlet velocity and jet angle. © 2022, International Scientific Information, Inc.. All rights reserved

Organizational e-readiness web: a model for evaluating e-readiness of Iranian commercial banks in order to develop e-banking

E-banking through mutual benefits for customers and banks has become a necessity in the banking industry nowadays. In spite of this, e-banking has not spread in Iran as it is appropriate.In a general categorization it can be said that E-readiness of banks and environmental e-readiness are two effective factors on development of e-banking which have been referred in different studies some models have been proposed in this regard in macro industries and others. However, no specific model has been proposed for the banks. This paper focuses on the first factor of "organizational e-readiness". Therefore, the main question of this study is that according to which model and toolthe state banks' readiness are evaluated in the field of development of e-banking in the state banks and how much is the current state of e-readiness of banks in this area? Accordingly, a model is presented as an organizational e-readiness web in this research, reviewing the organizational e-readiness evaluation models, and carried out research to identify organizational barriers and motivators of business/ e-banking development. According to the introduced dimensions, the banks enjoy relative readiness for the development of e-banking

Increasing the efficiency Proton exchange membrane (PEMFC) & other fuel cells through multi graphene layers including polymer membrane electrolyte

Multi layers Graphene has been simulated theoretically for hydrogen storage and oxygen diffusion at a single unit of fuel cell. Ion transport rate of DFAFC, PAFC, AFC, PEMFC, DMFC and SOFC fuel cells have been studied. AFC which uses an aqueous alkaline electrolyte is suitable for temperature below 90 degree and is appropriate for higher current applications, while PEMFC is suitable for lower temperature compared to others.  Thermodynamic equations have been investigated for those fuel cells in viewpoint of voltage output data. Effects of operating data including temperature (T), pressure (P), proton exchange membrane water content (λ) , and proton exchange membrane thickness  on the optimal performance of the irreversible fuel cells have been studied.Obviously, the efficiency of PEMFC extremely related to amount of the H2 concentration, water activities in catalyst substrates and polymer of electrolyte membranes, temperature, and such variables dependence in the direction of the fuel and air streams

Numerical simulation of large arrays of impinging jets on a flat surface

The objective of the present research is the prediction of large arrays of impingement jets using a computational model. The heat transfer and the force coefficient from single and multiple jet rows (1, 2, 4, 8, and infinity rows) for two different nozzle shapes as either orifice or straight pipe on a fixed flat surface were numerically investigated for drying applications to understand the physical mechanisms which affect the uniformity of the local heat transfer and pressure force coefficient as well as average heat transfer coefficient. The pipe has always a higher averaged Nu and pressure force coefficient compared to the orifice nozzle. Increasing the nozzle to surface distance and decreasing the jet impingement angle reduces the heat transfer and pressure force coefficient. The local Nu number curves for multiple jet rows exhibited many different shapes because of different interference intensities between adjacent jets and also the magnitude of cross-flow. The impact of multiple jet rows on averaged Nu number and jet force coefficient was negligible compared to the single jet row

Correlation development for jet impingement heat transfer and force on a moving curved surface

The effect of jet Reynolds number, jet exit angle, the nozzle to surface distance, jet to jet spacing on the heat transfer, and pressure force performance from multiple impinging round jets on a moving curved surface have been numerically evaluated. Two correlations are developed and validated for the average Nu number and the pressure force coefficient and the agreement between the CFD and correlations was reasonable. The surface motion effect becomes more pronounced on the Nu number distribution for low jet Re number, high jet to jet spacing, large jet to surface distance, and angled jets. The pressure force coefficient is highly dependent on the jet to surface distance and jet angle but relatively insensitive to jet Re number and jet to jet spacing. © 2022, International Scientific Information, Inc.. All rights reserved

Numerical study of jet impingement force and heat transfer on a moving curved suface

The effect of surface curvature, number of jets, number of jet rows, jet arrangement, crossflow, and surface motion on the heat transfer and pressure force performance from multiple impinging round jets on the moving flat and curved surface have been numerically evaluated. The more number of jets (more than three jets) has no significant effect on the average heat transfer rate. The more number of jet rows increases the strength of wall jets interference and crossflow effects and degrade the average heat transfer rates. There is a minor difference between inline and staggered arrangements on both moving flat and curved surfaces. The surface motion has a stronger effect on the impinging jets in the intermediate crossflow scheme than in the minimum crossflow scheme. The total average Nu on both moving flat and curved surfaces reduces with an increase in the velocity ratio and surface curvature. The pressure force is relatively insensitive to the surface motion on both moving flat and curved surfaces. © 2022, International Scientific Information, Inc.. All rights reserved

Optimal Recloser Setting, Considering Reliability and Power Quality in Distribution Networks

International audienceReclosers and fuses are the commonplace protective devices in distribution networks. A recloser can prevent long-time outages by clearing temporary faults before operation of the fuses in the system. Thus, it decreases the rate of long-term outages and improves system reliability and power quality. Despite positive features of reclosers, each operation of a recloser causes a momentary voltage interruption that exacerbates power quality. Nowadays, power quality issues have become more important because of the increasing use of sensitive equipment to voltage interruptions. According to the mentioned concerns, it seems necessary to set reclosers to strike a balance between power quality and the effectiveness of fuse saving scheme. Thus, we proposed a method to set reclosers. Due to the random nature of faults, the proposed method is stochastic based on the Monte Carlo method. The proposed method determines the optimal number of operations, reclosing intervals, and protection zones. The proposed method efficiency is evaluated according to the simulation results, and the proposed method is capable of establishing an optimal trade-off between power quality and protection efficiency