Sharif Digital Repository

In this paper, we present a design method of dual-band waveguide rectangular cavity filters, with a series in-line topology. The coupling matrix is based on asynchronously tuned designs, where two sets of resonances exist for the two bands. Thus the filter is inherently different than the typical dual-band designs in the literature, as existing designs utilize resonators at the same frequency. The design at Ku band validates the underlying idea and concept, and the theory of the detuned coupling matrix. This rectangular waveguide implementation can provide noticeable miniaturization in applications with high-power requirements  

The aim of this paper is to investigate the implementation of a molten carbonate fuel cell (MCFC) as a CO2 separator. By applying multi-objective optimization (MOO) using the genetic algorithm, the optimal values of operating load and the corresponding values of objective functions are obtained. Objective functions are minimization of the cost of electricity (COE) and minimization of CO2 emission rate. CO2 tax that is accounted as the pollution-related cost, transforming the environmental objective to the cost function. The results show that the MCFC stack which is fed by the syngas and gas turbine exhaust, not only reduces CO2 emission rate, but also produces electricity and reduces... 

Greenhouses are complex systems that require considerable amounts of energy. In order to optimize their performance, it is necessary to reduce the amount of energy per unit of crop produced. This requires a combined assessment of greenhouse energy balance and crop growth, as well as their interaction. In this work, more than 30 existing greenhouse models are reviewed and different algorithms are combined to propose an integrated energy-yield model. The physical model of greenhouse energy demand is based on the dynamic energy and mass balance while yield production is based on a physiological crop model. The integrated model is validated with observed energy demand and crop yield datasets... 

The aim of this study is to investigate the most important drivers of environmental impacts and identify the influence of parameters on the uncertainty of the environmental impacts in various climate zones and future climate scenarios. We couple a combined greenhouse energy demand-yield simulation tool with a life cycle assessment to identify the drivers for greenhouse energy, water and CO2 demand as well as yield production. Environmental impacts are evaluated using the methods of IPPC for assessing climate change and available water remaining (AWARE) for water scarcity impacts. Furthermore, we compare the results for all five main climate world regions. With a global sensitivity analysis,... 

The aim of this paper is to develop a simulation framework to minimise the cost associated with commercial greenhouse yields (production cost). Greenhouse energy demand and yield production models are coupled with a cost model to investigate the interaction between energy consumption costs and yield production benefits. The coupled model is defined as an optimisation problem to determine the optimal values of decision variables (e.g. cover material, heating and cooling technology, inside temperature and relative humidity set points, plant density, etc.), which result in minimum production cost as the objective function. The results show that the integrated energy demand-crop yield production... 

The aim of this study is to couple molten carbonate fuel cell (MCFC) stack with integrated gasification combined cycle fed by refinery residues, to remove CO2 from gas turbine exhaust gases that have CO2 emission rate of 14,200 ton/year. By applying multi-objective optimisation (MOO) using genetic algorithm, the optimal values of operating load and the corresponding values of objective functions are obtained. The MOO of the MCFC system regarding two scenarios is performed. The first scenario is minimisation of cost of electricity (COE) and CO2 emission rate. Objective functions of the second scenario are the same as in the first scenario while CO2 tax is taken into account. Results show that... 

Carbon emissions significantly contribute to global warming, amplifying the occurrence of extreme weather events and negatively impacting the overall environmental transformation. In line with the global commitment to combat climate change through the Paris Agreement (COP21), the European Union (EU) has formulated strategies aimed at achieving climate neutrality by 2050. To achieve this goal, EU member states focus on developing long-term national strategies (NLTSs) and implementing local plans to reduce greenhouse gas (GHG) emissions in alignment with EU objectives. This study focuses on the case of Sweden and aims to introduce a comprehensive data-driven framework that predicts CO2... 

In this paper we introduce a Simplified Single Particle Model (SSPM), which is obtained from the general mathematical formulation of Li-ion batteries. The model is validated by using different commercial graphite/LiFePO4 cells, and results show agreement with more complicated models and experimental data for low operating currents of less than 1C. A maximum relative error of less than 2% can be observed to estimate cell voltage in the plateau region of the charge/discharge curves. Therefore, the proposed model is suitable in the case of stand-alone renewable energy systems, where battery current is typically lower than C/10. By increasing the current, the SSPM deviates from more accurate...