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Anti-Icing System Simulation and Ice Acceration on Wing in Cold & Humidity Weather
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Massoud (Supervisor)
Abstract
The attention to ice accretion subject and its implementation have recently become very serious in our country due to a substantial need to a further understanding of this phenomenon and improving the design and construction of anti-ice systems for the airplanes in-hand. The subject of this study is the numerical simulation of ice accretion at the surface of airplanes, which is a technical approach in aerospace engineering. In other words, this study simulates the details of ice growth at different sections of an airplane wing considering wide ranges of different affecting parameters and conditions. To achieve this, we numerically solve the governing equations for two-phase flow of air and...
Cascade Impactor Modeling and Design
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Sani, Mahdi (Supervisor)
Abstract
Cascade impactors are the instruments which are used to assess the particle size distribution and the cut off diameter. Cascade impactors are wildly used for hygiene purposes, environmental, and toxicological studies. However, to find out the accurate size distribution, the cut off diameter of each stage which is different for different types of impactors with different geometry specifications should be determined. In this study first the basis of the cascade impactor operation is described. Next, different types of cascade impactors are introduced, and the Andersen Cascade Impactor (ACI) is chosen to design. The design criteria are explained and the dimension of each stage, entrance cone,...
Simualtion of Two-Phase Gas-Solid Flow in Electrostatic Precipitator to Increase Particulate Collection Efficiency Using Plate with Aerodynamic Bulges
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud (Supervisor) ; Zakeri, Ramin (Supervisor)
Abstract
Electrostatic precipitators (ESPs) are widely recognized for their pivotal role in the collection of dust and particulate matter. ESPs are essential to ensure a particle- and dust-free atmosphere in industrial and non-industrial work environments. With the ever-increasing significance of maintaining air quality at the desired standards, the role of ESPs has gained paramount importance in mitigating airborne pollutants and protecting public health. Achieving higher collection efficiency for particulate matter and attaining cleaner air is of great importance in the design and selection of precipitators. On the other hand, particle collection efficiency is considered as a crucial factor for ESP...
Improved charge collection efficiency of hollow sphere/nanoparticle composite TiO 2 electrodes for solid state dye sensitized solar cells
, Article Current Applied Physics ; Volume 13, Issue 2 , March , 2013 , Pages 371-376 ; 15671739 (ISSN) ; Mohammadpour, R ; Irajizad, A ; Taghavinia, N ; Dadgostar, S ; Samadpour, M ; Tajabadi, F ; Sharif University of Technology
2013
Abstract
The photoanodes of solid state dye sensitized solar cells (ss-DSCs) embedded with different contents of TiO 2 hollow spheres (HSs) were prepared and the photovoltaic performances were systematically characterized. TiO 2 hollow spheres were synthesized by a facile sacrificial templating method, grounded and added in different ratios to TiO 2 nanoparticle (NP) paste, from which composite HS/NP electrodes were fabricated. The composite photoanodes include hollow spheres of 300-700 nm with enhanced light scattering characteristics in visible range which leads to improved light absorption in conventional thin film electrodes of ss-DSC. By optimizing the amount of HSs in the paste, 40% improvement...
Improved photovoltaic performance of nanostructured solar cells by neodymium-doped TiO2 photoelectrode
,
Article
Materials Letters
;
Volume 159
,
November
,
2015
,
Pages 273-275
;
0167577X (ISSN)
; Mohammadpour, R
; Zad, A. I
; Taghavinia, N
;
Sharif University of Technology
Elsevier
2015
Abstract
Well-crystallized TiO2 and neodymium (Nd)-doped TiO2 nanoparticles with various doping levels were synthesized by hydrothermal method and utilized as the photoanode of nanostructured solar cells. The results indicated that Nd-doping was caused the absorption spectra shift to higher wavelength while the morphology and surface area were unchanged. As a result, by employing 0.4 mol% Nd in the TiO2 photoelectrode, the overall conversion efficiency of the cell reached 9.08% which is 26% higher than pure one. Based on the photo-electrochemical characterizations, the improvement is a consequence of electrons injection increment from dye to TiO2 conduction...
Dispersion and deposition of nanoparticles in microchannels with arrays of obstacles
, Article Microfluidics and Nanofluidics ; Volume 21, Issue 4 , 2017 ; 16134982 (ISSN) ; Moosavi, A ; Sadrhosseini, H ; Sharif University of Technology
Springer Verlag
2017
Abstract
Air pollutants are among the hazardous materials for human health. Therefore, many scientists are interested in removing particles from the carrier gas. In this study, flow of air and airborne particles through the virtual multi-fibrous filters that consist of different fiber cross-sectional shapes and arrangements is simulated where particle deposition and filtration performance are studied. Regular and irregular arrangements of fibers with the circular, elliptical, and equilateral triangular cross sections have been considered. Effects of important parameters such as solid volume fraction, internal structure, and filter thickness on particle collection efficiency and pressure drop are...
Fog harvesting: combination and comparison of different methods to maximize the collection efficiency
, Article SN Applied Sciences ; Volume 3, Issue 4 , 2021 ; 25233971 (ISSN) ; Kazerooni, H ; Sharif University of Technology
Springer Nature
2021
Abstract
Fog harvesting is an unconventional source of water that can be used in some regions with water scarcity to overcome water shortages. The most commonly used collectors are meshes which have intrinsic limitations, the most important of which are clogging and aerodynamic deviation of droplets around the wires. Here, three techniques are compared and combined to overcome these limitations, i.e., replacing the mesh with an array of vertical wires, addition of a hydrophobic layer to the wires, and forcing the ionized droplets to move toward the wires by applying an electric field. The combination of these techniques was found to result in higher fog harvesting efficiency compared to each...
Nitrogen-doped submicron-size TiO2 particles as bifunctional light scatterers in dye-sensitized solar cells
, Article Applied Physics A: Materials Science and Processing ; Volume 119, Issue 4 , 2015 , Pages 1283-1290 ; 09478396 (ISSN) ; Mohammadpour, R ; Iraji zad, A ; Taghavinia, N ; Sharif University of Technology
Springer Verlag
2015
Abstract
The structural, electrical, optical, and photovoltaic properties of aggregated submicron nitrogen-doped TiO2 particles (NTiO2) and the influence of utilizing them, in comparison with undoped ones, as the light-scattering layer of dye-sensitized solar cells were investigated. Field emission scanning electron microscope, X-ray diffraction, and diffuse reflectance spectra showed that both type samples have similar morphology, crystal phase, and scattering feature. Moreover, photoluminescence, Mott–Schottkey, and photovoltaic characteristics such as IMPS/IMVS and charge extraction analysis indicated that the NTiO2 layer is an efficient scatterer in two aspects: enhancement of light-harvesting...
Enhanced electron collection efficiency of nanostructured dye-sensitized solar cells by incorporating TiO2 cubes
, Article Journal of the American Ceramic Society ; Volume 101, Issue 1 , 2018 , Pages 293-306 ; 00027820 (ISSN) ; Mohammadi, M. R ; Sharif University of Technology
Blackwell Publishing Inc
2018
Abstract
Herein, enhancement of dye-sensitized solar cell (DSC) performance is reported by combining the merits of the dye loading of TiO2 nanoparticles and light scattering, straight carrier transport path, and efficient electron collection efficiency of TiO2 cubes. We fabricate DSC devices with various arrangement styles and compositions of the electrodes in the forms of monolayer and double layer films. For this purpose, the solvothermal synthesized TiO2 cubic particles (100-600 nm) are employed as the scattering layer, whereas TiO2 nanoparticles (15-30 nm) synthesized via a combination of solvothermal and sol-gel routes are used as the active layer of devices. We improve the photovoltaic...
Atomic layer deposition of an effective interface layer of tin for efficient and hysteresis-free mesoscopic perovskite solar cells
, Article ACS Applied Materials and Interfaces ; Volume 12, Issue 7 , 2020 , Pages 8098-8106 ; Tavakoli, M. M ; Prochowicz, D ; Yadav, P ; Lote, S. S ; Bhoite, S. P ; Nimbalkar, A ; Hong, C. K ; Sharif University of Technology
American Chemical Society
2020
Abstract
Perovskite solar cells (PSCs) have experienced outstanding advances in power conversion efficiencies (PCEs) by employing new electron transport layers (ETLs), interface engineering, optimizing perovskite morphology, and improving charge collection efficiency. In this work, we study the role of a new ultrathin interface layer of titanium nitride (TiN) conformally deposited on a mesoporous TiO2 (mp-TiO2) scaffold using the atomic layer deposition method. Our characterization results revealed that the presence of TiN at the ETL/perovskite interface improves the charge collection as well as reduces the interface recombination. We find that the morphology (grain size) and optical properties of...