@article { author = {Mohammadi, B. and Ranjbar, S. F. and Ajabshirchi, Y.}, title = {Comprehensive evaluation of a semi-solar greenhouse:Energy, exergy, and economic analyses with experimental validation}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2613-2627}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.53709.3375}, abstract = {This study deals with dynamic modeling and analyzing of an innovative semi-solar greenhouse structure applying MATLAB software from the viewpoints of energy, exergy and economic. This Modeling is applied to predict the temperatures of four different points inside the semi-solar greenhouse, regarding the evapotranspiration of the crop. Measured data recorded from the constructed typical semi-solar greenhouse is used to evaluate the results of the proposed thermodynamic analysis. Measurements during the experiment show considerable temperature difference of 20 ℃ between the indoor and outdoor air. The mean values of 5.94% and 2.06℃ for MAPE(Mean Absolute Percentage Error) and RMSE(Root Mean Squared Error) indicates the accuracy of the thermal simulation. Furthermore, in different heat and mass transfer processes, the total exergy destruction values are analyzed. The target of this research is considered as providing suitable environmental conditions for the inside of the greenhouse. In this respect, the greenhouse air unit cost for each time step of one minute is inspected. By increasing the interest rate from 10% to 20% the greenhouse air unit cost raises almost twice. Decrease of about 45.36 % in total exergy destruction is obtained by the technique of applying double layer glass as the greenhouse cover.}, keywords = {Dynamic model,Semi-solar greenhouse,Air unit cost,Exergy Destruction}, url = {https://scientiairanica.sharif.edu/article_22340.html}, eprint = {https://scientiairanica.sharif.edu/article_22340_bb93077054df9671b64d3018959b6414.pdf} } @article { author = {Bayat, S. and Nejat Pishkenari, H. and Salarieh, H.}, title = {Observation of Stage Position in a 2-Axis Nano-positioner Using Hybrid Kalman Filter}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2628-2638}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.54441.3752}, abstract = {This paper presents a novel method for observation of the stage position in a 2D Nano-positioning system based on a hybrid Kalman filter. In the proposed method, there is no need to measure the stage position directly using complex and costly capacity sensors. Instead, by using traditional piezo actuators equipped with strain gauge sensors, the deflection of the magnification system at the position of actuators is measured. Then, by employing a powerful estimation algorithm named as Kalman filter, the displacements of the stage are observed. The designed hybrid Kalman filter uses dynamical equations of motion in the prediction step. The piezo actuators deflections are measured and exploited to correct the predicted values for the system state variables. In order to simulate realistic conditions, a relatively exact COMSOL model has been developed for the nano-positioner where noise has been added to the piezo displacements obtained by simulating this model and these noisy data are used as measurements in the Kalman filter algorithm. The designed hybrid Kalman filter is examined for three different updating time steps. The results show that the designed Kalman filter appropriately estimates the stage displacements, and its accuracy is improved when the filter time step reduces.}, keywords = {Nano positioning stage,observer,hybrid Kalman filter}, url = {https://scientiairanica.sharif.edu/article_22456.html}, eprint = {https://scientiairanica.sharif.edu/article_22456_4c2630ac5fdbe146c372110720f59fb2.pdf} } @article { author = {Sundriyal, S. and Vipin, vipin and Walia, R. S.}, title = {Study on parameter’s optimization for the minimizing of the residual stress in powder mixed near-dry electric discharge machining}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2639-2654}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.55837.4429}, abstract = {There are some undesired effects left in the machined products by electric discharge machining (EDM) and the most prominent among those is the residual stress. These induced residual stresses influence fatigue behavior, dimensional stability, and stress corrosion which is responsible for the failure of the machined product. It was observed that the products obtained by powder mixed near dry- EDM or (PMND-EDM) have a considerably low value of residual stress (RS). The objective of this research is to minimize the residual stresses induced in the machined workpiece (EN-31) by optimizing the process parameters which affects the machining characteristics significantly. Selected parameters were tool diameter, mist flow rate, metallic powder concentration, and mist pressure while the workpiece selected was EN-31 due to its desirable mechanical properties and immense applications in the manufacturing industry. The minimum value of residual stress at optimized values of process parameters was found to be 106.32 MPa.}, keywords = {  Residual stress,EDM,Powder,Near dry,X-ray method}, url = {https://scientiairanica.sharif.edu/article_22458.html}, eprint = {https://scientiairanica.sharif.edu/article_22458_7cde1824986d77c8347987deecec2c89.pdf} } @article { author = {Sahinoglu, A. and Rafighi, M.}, title = {Machinability of hardened AISI S1 cold work tool steel using cubic boron nitride}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2655-2670}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.55772.4398}, abstract = {Recently, hard turning became an interesting method to the manufacturers as an alternative to the grinding process due to its superior features such as good surface quality, good productivity, lower production costs, lower power consumption, and shorter processing time. Despite its considerable benefits, hard turning is a difficult process that needs advanced cutting inserts such as ceramics and cubic boron nitride. However, these cutting inserts are costly and should be used properly by choosing appropriate machining parameters. In the presented work, the hard turning process was performed to investigate the machinability of AISI S1 cold work tool steel using cubic boron nitride insert. The relation between machining parameters namely, depth of cut, cutting speed, and feed rate on the responses such as power consumption, surface roughness, and machining sound was found using a full factorial orthogonal array of response surface methodology. In addition, analysis of variance was used to identify the most important machining parameters that influence output parameters. Based on the results, surface roughness was dominantly affected by feed rate, whereas, sound and power consumption were influenced by all machining parameters especially cutting speed and feed rate. A good agreement between the experimental and the predicted values were observed.}, keywords = {AISI S1 steel,hard turning,surface roughness,machining sound,power consumption,Response Surface Methodology}, url = {https://scientiairanica.sharif.edu/article_22390.html}, eprint = {https://scientiairanica.sharif.edu/article_22390_878b0e023f9131cb0017364105230b68.pdf} } @article { author = {Adibi, T. and Razavi, S. E. and Adibi, O. and Vajdi, M. and Sadegh Moghanlou, F.}, title = {The response of nano-ceramic doped fluids in heat convection models: A characteristics-based numerical approach}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2671-2683}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56574.4794}, abstract = {In this paper, forced, free, and mixed convections in incompressible flow were studied numerically. Nano-sized Al2O3, TiO2, MgO, and ZnO ceramics with water were considered as nano-fluids. Simulations were carried out for cavity flow with different boundary conditions and aspect ratios, as well as flow over stationary and rotating cylinders. The mean Nusselt number ((Nu) ̅) and friction factor for cavity flow and (Nu) ̅ for flow over a cylinder were compared for different nano-fluids. A new code was developed in FORTRAN 95 for numerical simulations. A fifth-order Runge-Kutta method for time discretization and a characteristic-based scheme for convective terms were used in this code. The averaging scheme on the secondary cells is used to obtain viscous fluxes. Primary results are validated with other researcher's outputs. Results showed that MgO-water and ZnO-water had maximum and minimum heat transfer rates, respectively. Moreover, maximum and minimum shear stresses were recorded for the Al2O3-water and TiO2-water, respectively. Using nanofluid increases the heat transfer rate between 15 and 37 percent depending on the Richardson number and selected nano-particles.}, keywords = {Nano-fluid,mixed convection,cavity,Flow over a cylinder,Richardson number}, url = {https://scientiairanica.sharif.edu/article_22160.html}, eprint = {https://scientiairanica.sharif.edu/article_22160_21611bc6a8d1f78e70161b22426f9be0.pdf} } @article { author = {Kumruoglu, L. C.}, title = {Prediction of shrinkage ratio of ZA 27 die casting alloy with artificial neural network, computer aided simulation and comparison with experimental studies}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2684-2700}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.54596.3824}, abstract = {In the cast alloys with a long freezing range such as ZA-27, casting defects such as porosity and shrinkage will occur if casting variables are not controlled carefully. In this study, the effect of casting variables on shrinkage and micro-porosity defects in ZA-27 was investigated. The defects of casting were predicted with Artificial Neural Network algorithms. The cooling rate, solidification time, temperature, liquid phase, initial mold temperature, and %shrinkage were obtained from a series of simulation- experimental tests. The heat transfer coefficient of ZA-27 and graphite die was calculated as 2000 W/(m2K). In the samples poured into the mold heated at 350 °C, the minimum feeder shrinkage volume was observed. Locations of the chronic Hotspot and Shrinkage problem was estimated. It was observed that the casting heated to 150 °C had wide-deep shrinkage on the upper and lateral surfaces of the feeder. A good correlation was obtained between the modeling results of the ANN and the experimental results. Optimum ANNs were designed, trained, and tested to predict the shrinkage rate for various initial mold temperatures and physical conditions. Thanks to the sigmoid (sigmoaxon) function training, the most systematic modeling ANN set was revealed with 99% (Vol. 7.65% Shrinkage) prediction.}, keywords = {CASTING,Simulation,Heat Transfer,ANN,SHRINKAGE, ZA-27}, url = {https://scientiairanica.sharif.edu/article_22265.html}, eprint = {https://scientiairanica.sharif.edu/article_22265_7bd89217da813bdd10864688fbb6ff6e.pdf} } @article { author = {Sahu, P. and Sharma, N. and Panda, S. k.}, title = {Multi-layer advanced fiber hybridisation (glass-carbon-Kevlar) and variable stiffness effect on composite structure responses (stress and deformation): An FE approach}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2701-2718}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2020.56810.4920}, abstract = {This article reported the influence of one/more numbers advanced layer fibre hybridization effect on the composite structural stiffness and the stress behaviour under the variable loading (uniformly distributed and sinusoidal) are computed numerically through an isoparametric finite element approach. This is the first time the hybrid composite panel model is derived in the framework of the higher-order kinematic model to satisfy the inter-laminar stress continuity via the strains. The necessary structural equilibrium equations under the influence of variable mechanical loadings are derived through the variational principle to compute the panel’s central point deflections, as well as the stress values. The varied structural stiffness and their corresponding deflection parameters due to the hybridization of different advanced fibres (Carbon/Glass/Kevlar) are obtained through an in-house computer code (prepared in MATLAB) by incorporating the necessary elastic constant through the constitutive relationship. The steadiness of the numerical solution is confirmed and extended further to verify the necessary solution correctness by solving a different number of examples similar to the published results. The influences of structural parameters relevant to the geometry, boundary conditions and the order of hybridizing layers on the bending strength have been highlighted by solving a series of examples and explained in details.}, keywords = {Flexural behaviour,hybrid composite laminates,HSDT,geometrical parameters,FEM,MATLAB}, url = {https://scientiairanica.sharif.edu/article_22105.html}, eprint = {https://scientiairanica.sharif.edu/article_22105_edf9407464d28e42afe26af988adc515.pdf} } @article { author = {Ghorbani, R. and T. Manzari, M. and Hajilouy-Benisi, A.}, title = {Development of a saturation-based Mu(I)-rheology for wet granular materials using discrete element method}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2719-2732}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.56993.5014}, abstract = {The discrete element method (DEM) is used to establish a rheological model that relates the apparent viscosity of a granular material to shear rate, normal stress, and water saturation. A theoretical model is developed to determine water distribution and water-induced forces between particles for different saturations. The resulting forces are embedded in a 3D shear cell as a numerical rheometer and a wet specimen is sheared between two walls. A power law rheological model is obtained as a function of inertia number and saturation. It was found that up to a critical saturation, the apparent viscosity increases with saturation and is higher than that of the dry specimen. However, when the saturation exceeds a critical value, the viscosity suddenly drops below that of dry condition. To evaluate the model, the collapse of two-dimensional granular material on a horizontal rigid bed is studied using continuum-based numerical simulation which utilizes the proposed rheological model.}, keywords = {Rheological model,DEM,Inertia number,Water saturation,Spherical grains}, url = {https://scientiairanica.sharif.edu/article_22208.html}, eprint = {https://scientiairanica.sharif.edu/article_22208_20bde0120f9acd58c24e6f4e6abae599.pdf} } @article { author = {Esmaeilion, F. and Ahmadi, A. and Dashti, R.}, title = {Exergy-economic-environment optimization of the waste-to-energy power plant using Multi-Objective Particle-Swarm Optimization (MOPSO)}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2733-2750}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2021.55633.4323}, abstract = {This paper brings together the benefits of the results of exergy, exergoeconomic, exergoenvironmental analysis, and ‎optimization for a waste-to-energy (WTE) power plant. Initially, exergoeconomic balances for each stream were ‎calculated. For validating the current simulations, the actual data of the Amsterdam WTE power plant in working ‎conditions were examined. Moreover, the behaviors of the influential parameters on the objective functions were ‎evaluated. In order to perform multi-objective optimization, the Multi-Objective Particle-Swarm Optimization‎ ‎‎(MOPSO) algorithm is implemented. To obtain optimum operating conditions, 14 design parameters, and 3 ‎objective functions are considered, while the total cost rate, total exergy efficiency of the cycle, and environmental ‎impacts are the objective functions. Finally, the TOPSIS decision-making method determined optimum-operating ‎conditions. The results of exergy analysis indicated that the most exergy destruction belonged to the incinerator unit ‎at 66%. Instead, the pumps contributed the least in this field, (approximately 1%). Because of the optimization ‎process, the total exergy efficiency of the power plant increased from 30.89% to 38.9% while the total cost rate was ‎‎5188.05 USD/hour. By comparison between the obtained results from the optimization procedure, introducing ‎optimum working conditions has caused an increase in exergy efficiency and reduced exergy destruction for ‎components.}, keywords = {Exergy,MOPSO,Exergoenvironmental,exergoeconomic,Waste-to-energy}, url = {https://scientiairanica.sharif.edu/article_22202.html}, eprint = {https://scientiairanica.sharif.edu/article_22202_3a5d0fab3780224bf3b7dd31e9d75587.pdf} } @article { author = {Nazemian, A. and Ghadimi, P.}, title = {Automated CFD-based optimization of inverted bow shape of a trimaran ship: An applicable and efficient optimization platform}, journal = {Scientia Iranica}, volume = {28}, number = {5}, pages = {2751-2768}, year = {2021}, publisher = {Sharif University of Technology}, issn = {1026-3098}, eissn = {2345-3605}, doi = {10.24200/sci.2020.56644.4833}, abstract = {This paper investigates the improvement of bow region of a trimaran ship hull, proposing a CFD-based automated approach to reduce total resistance. Two main goals are pursued; to create and develop a useful optimization platform for ship hull modification, and then investigate the influence of different inverted bow on hydrodynamic performance of trimaran ship. A wave-piercing bow trimaran hull is the baseline design. Ship bow is redesigned by Arbitrary Shape Deformation (ASD) technique that defines the input variables for optimization process. The objective function is the drag force and this study is conducted at cruise speed. To accomplish this task, two optimization methods are sequentially applied. A Latin Hypercube Sampling tool distributes design points and an RBF based surrogated model is constructed to investigate system behavior. Final optimum design in Design of Experiment (DOE) study is introduced to direct optimization SHERPA algorithm. Integration of CFD solver, geometric parametrization, and optimizer tool is managed by HEEDS MDO package with a multi-connection approach. Optimization results show successful optimization along with 10.2% resistance reduction. Comparison between initial and optimized hull demonstrates that the proposed optimization platform can be used for ship hull optimization in industrial application with significantly reduced computational time and effort.}, keywords = {Trimaran hull,Arbitrary Shape Deformation (ASD),CFD,optimization,Total resistance,Surrogated model}, url = {https://scientiairanica.sharif.edu/article_22110.html}, eprint = {https://scientiairanica.sharif.edu/article_22110_a96f64298ebeda13ca7b6266b7581814.pdf} }