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Showing 8 results for Sola

Babaei R., Varahram N., Davami P., Sabzevarzadeh A.,
Volume 1, Issue 2 (6-2004)

In this investigation, chr('94')5 2-D Finite Volume Method (FVM) with unstructured triangular mesh is developed to simulate the mould filling process. The simulation of fluid flow and track of free surface is based on the Marker And Cell (MAC) technique. This technique has capability ofhandling the arbitrary curved solid boundaries in the casting processes. In order to verify the computational results of the simulation, a thin disk plate with transparent mould was tested. The mould filling process was recorded using a 16mm high-speed camera. Images were analyzed frame by frame, in order to tracking of free surface and filling rate during mould filling. Comparison between the experimental method and the simulation results has shown a good agreement.
Mirbagheri S.m.h., Ashouri H., Varahram N., Davami P.,
Volume 1, Issue 2 (6-2004)

In this investigation a new model was developed to calculate gas pressure at the melt/foam interface (Gap) resulting from foam degradation during mould filling in the Lost Foam Casting (LFC) process. Different aspects of the process, such as foam degradation, gas elimination, transient mass, heat transfer, and permeability of the refractory coating were incorporated into this model. A Computational Fluid Dynamic (CFD) code was developed based on the numerical technique of the SOLution Algorithm- Volume Of Fluid (SOLA- VOF) utilizing model, for the simulation and prediction of the fluid flow in the LFC process. In order to verify the computational results of the simulation, a thin plate of gray iron was poured into a transparentfoam mould. The mould filling process was recorded using a 16mm high-speed camera. Images were analysed frame by frame, in order to measuring foam depolymerization rate and the gap volume during mould filling. Comparison between the experimental method and the simulation results, for the LFC filling sequence, has shown a good agreement.
N. Hatami,, R. Babaei, P. Davami,
Volume 5, Issue 2 (6-2008)

Abstract: In this study an algorithm for mold-filling simulation with consideration of surface tension has been developed based on a SOLA VOF scheme. As the governing equations, the Navier-Stokes equations for incompressible and laminar flows were used. We proposed a way of considering surface tension in mold-filling simulation. The proposed scheme for surface tension was based on the continuum surface force (CSF) model we could confirm the remarkable effectiveness of the surface tension by experiment which concluded in very positive outcome.
M. Alzamani, A. Shokuhfar, E. Eghdam, S. Mastal,
Volume 10, Issue 1 (3-2013)

Abstract:In the present research, SiO2–TiO2 nanostructure films were successfully prepared on windshields using the sol–gel technique for photocatalytic applications. To prevent the thermal diffusion of the sodium ions from the glass to TiO2 films, the SiO2 layer was pre-coated on the glass by the sol–gel method. The substrates were dipped in the sol and withdrawn with the speed of 6cm/min-1 to make a gel coating film. The coated films were dried for 2 days at 27 °C to allow slow solvent evaporation and condensation reactions due to rapid sol–gel reaction of Titania precursor. Then, the films were annealed at 100 °C for 30min and at the final temperature (500, 700 °C) for 30 min continuously. The structure and surface morphology properties, which are as a function of annealing temperature, have been studied by SEM FE-SEM and XRD. The FE-SEM surface morphology results indicate that the particle size increases from 19 to 42 nm by increasing the annealing temperature from 500 °C to 700 °C. Likewise, XRD illustrate the crystal anatase and rutile as main phases for TiO2-SiO2 films annealed at 500 °C and 700 °C respectively. This procedure resulted in transparent, crack-free SiO2–TiO2 films.
M. Maleki, S. M. Rozati,
Volume 12, Issue 4 (12-2015)

In this paper, polycrystalline pure zinc oxide nano structured thin films were deposited on two kinds of single crystal and polycrystalline of p and n type Si in three different substrate temperatures of 300, 400 and 500C by low cost APCVD method. Structural, electrical and optical properties of these thin films were characterized by X ray diffraction, two point probe method and UV visible spectrophotometer respectively. IV measurements of these heterojunctions showed that turn on voltage and series resistance will increase with increasing substrate temperature in polycrystalline Si, while in single crystal Si, turn on voltage will decrease. Although they are acceptable diodes, their efficiency as a heterojunction solar cell are so low

R. Ubaid, S. Saroj Kumar, S. Hemalatha,
Volume 15, Issue 3 (9-2018)

Drug resistant pathogenic microbes have been causing serious health issues resulting in the substantial increase of death rates and morbidity paving the way for nanoparticles to be utilized as antimicrobial agents. This study was performed to evaluate the effectiveness of CuNPs on the growth of drug resistant clinical isolates of Streptococcus pyogenes, Enterococcus faecium and Enterococcus faecalis. Minimum inhibitory concentration of CuNPs against Streptococcus pyogenes, Enterococcus faecium and Enterococcus faecalis was found to be 1.25. 1.25 and 0.625 mg/ml and minimum bactericidal concentration against the same isolates was found to be 2.5, 2.5 and 5 mg/ml respectively. The ratio of MBC/MIC, referred to as tolerance level, was calculated for all the isolates which signifies the bactericidal or bacteriostatic effect of any antimicrobial agent. For Streptococcus pyogenes and Enterococcus faecium, the tolerance level was 2 while as for Enterococcus faecalis, it was 8. Antibiotic susceptibility results were calculated which showed that the isolates were resistant to Ampicillin (10 µg), Amoxycillin (30 µg) and Aztreonam (30 µg). Susceptibility results were followed by calculating multiple antibiotic resistance indices (MARI). MARI is an important tool which gives an idea about the bacterial resistance in a given population. For all the three isolates, MARI results were equivalent to 1 because of their resistance towards all the three antibiotics used. Antimicrobial activity through well-plate method was carried out and inhibitory effect of CuNPs on biofilm formation was evaluated.

M. Mahdi, A. Abdul-Hameed, B. Ali, H.f Al-Taay,
Volume 17, Issue 1 (3-2020)

Silicon nanowires (SiNWs) are synthesized through a metal-assisted chemical etching (MACE) method using Si(100) substrates and silver (Ag) as a catalyst. Scanning electron microscope (SEM) images confirmed that length of prepared SiNWs was increased when etching time increased. The prepared SiNWs demonstrated considerably low light reflectance at a wavelength range of 200–1100 nm. The photoluminescence (PL) spectra of the grown SiNWs showed a broad emission band peaked at a wavelength of about 750 nm. A solar cell and photodetector based on heterojunction SiNWs/PEDOT:PSS were fabricated using SiNWs that prepared with different etching time and its J–V, sensitivity, and time response were investigated. The conversion efficiency of fabricated solar cell was increased from 0.39% to 0.68% when wire length decreased from 24 µm to 21 µm, respectively. However, the sensitivity of the heterojunction SiNWs/PEDOT:PSS photodetector was decreased from 53774% to 36826% when wire length decreased from 24 µm to 21 µm, respectively.

Mohammad Reza Zamani Meymian, Razieh Keshtmand,
Volume 18, Issue 4 (12-2021)

Tin oxide (SnO2) is used as an electron transport layer (ETL) in perovskite solar cells with a planar structure due to its good transparency and energy level alignment with the perovskite layer. The modification interface of the electron transport layer and the perovskite absorber layer plays an important role in the efficient charge extraction process at the interface. In this study, planar perovskite solar cells with configuration (FTO/SnO2/mixed-cation perovskite/CuInS2/Au) were prepared to investigate the effect of UV-Ozone (UVO) treated SnO2 as ETL on the performance of devices. ETL treatment was performed at different times (0 to 60 min). It is shown that surface wetting was improved by UVO treating the SnO2 films prior to deposition of the perovskite layer, which improves the contact between the ETL and the perovskite layer, allowing electron transport at the interface to be more efficient. Contact angle, SEM, photoluminescence spectra, and current density-voltage tests were measured to characterize the photovoltaic of the cells. The best PSC performance with a power conversion efficiency of 10.96% was achieved using UVO-treated SnO2 ETL for 30 min, whereas the power conversion efficiency of the perovskite solar cells with SnO2 ETL without UVO treatment was 4.34%.

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