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Micro-scale evolution of mechanical properties of glass-ceramic sealant for solid oxide fuel/electrolysis cells
, Article Ceramics International ; Volume 47, Issue 3 , 2021 , Pages 3884-3891 ; 02728842 (ISSN) ; Malzbender, J ; Groß Barsnick, S. M ; Abdoli, H ; Kokabi, A. H ; Faghihi Sani, M. A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The structural integrity of the sealant is critical for the reliability of solid oxide cells (SOCs) stacks. In this study, elastic modulus (E), hardness (H) and fracture toughness (KIC) of a rapid crystallizing glass of BaO–CaO–SiO2 system termed “sealant G” are reported as determined using an indentation test method at room temperature. A wide range of indentation loads (1 mN–10 N) was used to investigate the load-dependency of these mechanical properties. Values of 95 ± 12 GPa, 5.8 ± 0.2 GPa and 1.15 ± 0.07 MPa m0.5 were derived for E, H and KIC using the most suitable indentation loads. An application relevant annealing treatment of 500 h at 800 °C does not lead to a significant change of...
Longitudinal quantitative assessment of covid-19 infection progression from chest CTs
, Article 24th International Conference on Medical Image Computing and Computer Assisted Intervention, MICCAI 2021, 27 September 2021 through 1 October 2021 ; Volume 12907 LNCS , 2021 , Pages 273-282 ; 03029743 (ISSN); 9783030872335 (ISBN) ; Goli, L ; Paschali, M ; Khakzar, A ; Keicher, M ; Czempiel, T ; Burian, E ; Braren, R ; Navab, N ; Wendler, T ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Chest computed tomography (CT) has played an essential diagnostic role in assessing patients with COVID-19 by showing disease-specific image features such as ground-glass opacity and consolidation. Image segmentation methods have proven to help quantify the disease and even help predict the outcome. The availability of longitudinal CT series may also result in an efficient and effective method to reliably assess the progression of COVID-19, monitor the healing process and the response to different therapeutic strategies. In this paper, we propose a new framework to identify infection at a voxel level (identification of healthy lung, consolidation, and ground-glass opacity) and visualize the...
The non-linear effect of oil polarity on the efficiency of low salinity waterflooding: A pore-level investigation
, Article Journal of Molecular Liquids ; January , 2021 ; 01677322 (ISSN) ; Mohammadi, S ; Mahani, H ; Ayatollahi, S ; Sharif University of Technology
Elsevier B. V
2021
Abstract
Oil polarity is an important property impacting the efficiency of low salinity waterflooding (LSWF). It directly affects fluid/fluid and rock/fluid interactions, controlling the interfacial properties and forces. However, the current findings in the literature on the effect of concentration of polar components on oil recovery by LSWF are contradictory. Therefore, the main objective of this paper is to investigate how the type of non-polar fractions and the concentration of acidic polar oil constituents change the trapped oil saturation at the pore-scale during LSWF. In this regard, we conducted a series of microfluidics LSWF experiments in both secondary and tertiary modes, using clay-free...
Characterization of etched glass surfaces by wave scattering
, Article Surface and Interface Analysis ; Volume 37, Issue 7 , 2005 , Pages 641-645 ; 01422421 (ISSN) ; Mahdavi, S. M ; Iraji Zad, A ; Kaghazchi, P ; Sharif University of Technology
2005
Abstract
The roughness of glass surfaces after different stages of etching is investigated by reflection measurements with a spectrophotometer, light scattering, atomic force microscopy (AFM, on a small scale) and profilometry (on a large scale). The results suggest that there are three regimes during etching, according to their optical reflectivity and roughness. The first and the second regimes are studied by the Kirchhoff theory and the third one is studied by the optical geometric theory. Also, the roughness obtained by optical scattering is compared with the AFM results. Copyright © 2005 John Wiley & Sons, Ltd
Radiopaque crystalline, non-crystalline and nanostructured bioceramics
, Article Materials ; Volume 15, Issue 21 , 2022 ; 19961944 (ISSN) ; Gonçalves, G. V. S ; Barreto, M. E. V ; Lima, E. P. N ; Cerqueira, G. R. C ; Sousa, J. A ; Malek Khachatourian, A ; Souza, M. K. S ; Silva, S. M. L ; Fook, M. V. L ; Baino, F ; Sharif University of Technology
MDPI
2022
Abstract
Radiopacity is sometimes an essential characteristic of biomaterials that can help clinicians perform follow-ups during pre- and post-interventional radiological imaging. Due to their chemical composition and structure, most bioceramics are inherently radiopaque but can still be doped/mixed with radiopacifiers to increase their visualization during or after medical procedures. The radiopacifiers are frequently heavy elements of the periodic table, such as Bi, Zr, Sr, Ba, Ta, Zn, Y, etc., or their relevant compounds that can confer enhanced radiopacity. Radiopaque bioceramics are also intriguing additives for biopolymers and hybrids, which are extensively researched and developed nowadays for...
Influence of Microstructure on Mechanical Properties and Fracture Behavior of Hybrid PP/GF/CaCO3 Composites
, M.Sc. Thesis Sharif University of Technology ; Ekrami, Ali Akbar (Supervisor) ; Bagheri, Reza (Supervisor)
Abstract
Homo-polymer of Polypropylene is a commodity thermoplastic with good physical and mechanical properties along with fair recyclability and cost. However, its application is limited in some cases, especially in automotive industry, due to a lack of toughness. One of the approaches for PP toughening is the copolymerization of PP with some ethylene co-monomers. However, existence of elastomers in this kind of polymers causes a decrease in tensile properties. Besides, glass fibers improve tensile properties of homo-and co-PP and decrease toughness of co-polymers but result in an increase for homo-polymers. A rise in expenditure of energy due to increasing the processing temperature and...
Experimental Investigation of Mechanical Behavior of Structural Concrete with Combination of Waste Glass and Silica Fume
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Ali Reza (Supervisor)
Abstract
Concrete is the second most structural material in the world. So attention and promotion of the concrete mix design with respect to variable issues and requirements, is very important. On the other hand, these days environment and its pollution has become very popular discussion. Waste-glass which is produced by human products is one of the environmental pollutants. In this thesis it replaces some aggregate in concrete and it can reduce the level of this material in the world. Also we study effects of silica-fume as cement replacement and properties enhancer in our concrete mix design and see how it can ...
Chitosan–Bioactive Glass Composite Coating on Nd-Fe-B Magnetic Alloy Substrate by Electrophoretic Deposition
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
This research work deals with application of poly-saccharide to improve coating process of bioactive ceramic composite on aNd-Fe-B magnetic alloy substrate. Bioactive glass particles were synthesized through a sol-gel process and coated in the form of composite with poly-saccharide onto a magnetic substrate by electrophoretic deposition technique. Stable suspensions of 0.5 gr/lit polysaccharide polymer-ceramic were prepared using bioactive glass particles (<1µm), acetic acid 1%. The influence of added water to ethanol, pH and tri-ethanol-amine (TEA) additive on suspension stability, deposition rate and coating’s structure was investigated. It was shown that by increasing the water to ethanol...
Electrical behaviour of glass/ carbon- phenolic conductive hybrid composite woven used in electrostatics precipitator filter
, Article International Journal of Electrochemical Science ; Vol. 9, issue. 11 , 2014 , p. 6416-6430 ; Nazari, S. A ; Sadeghbeigi, N ; Karimzadeh, A ; Sharif University of Technology
Abstract
Electrical behavior of hybrid conductive composites made of phenolic resin, graphite woven, glass woven and graphite nano powder has been studied for the first time in the present research to apply as collecting plates in electro static precipitators. To this purpose, two types of four-layer composites smeared with phenolic resin by different amounts of graphite nano powder then produced at 120°C and 200 bars with proper curing cycle. Finally, electrical resistivity of all the plates undergoing impact loading after different rapping cycles was measured by means of a repetitive rapping tester system particularly manufactured for this task. This study performs changes in mechanical behavior of...
Effect of utilizing glass fiber-reinforced polymer on exural strengthening of rc arches
, Article Scientia Iranica ; Volume 26, Issue 4A , 2019 , Pages 2299-2309 ; 10263098 (ISSN) ; Khaloo, A. R ; Shekarchi, M ; Kazemian, A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
An experimental study of the. flexural behavior of Reinforced-Concrete (RC) arches strengthened with Glass Fiber-Reinforced Polymer (GFRP) layers was performed. A total of 36 specimens including 3 un-strengthenod (control) and 33 strengthened RC arches were tested under centrally concentrated point load. The variables of this study were steel reinforcement ratio, number of GFRP layers, and location and arrangement of GFRP layers. Failure mode, load-displacement response of specimens, crack propagation patterns, and GFRP debonding were examined. The extrados strengthening method was shown to Ix1 more effective than the intrados strengthening one in improving the failure load and rigidity of...
Deformation mechanism of epoxy/clay nanocomposite
, Article European Polymer Journal ; Volume 43, Issue 3 , 2007 , Pages 782-788 ; 00143057 (ISSN) ; Bagheri, R ; Sharif University of Technology
2007
Abstract
Polymer-layered silicate nanocomposites have been noticed recently due to their outstanding properties. The mechanical properties and deformation mechanism of epoxy/montmorillonite nanocomposites under compressive and flexural loadings were investigated. A reduction in compressive and flexural yield stress and also glass transition temperature with increasing the amount of organoclay was observed. This change in mechanical behavior of epoxy can be explained with observation of plastic deformation mechanism. The study of deformation mechanism revealed that presence of organoclay accelerates shear yielding in epoxy. Microscopic evaluation illustrated that nanoparticles in this system act as...
Etched glass surfaces, atomic force microscopy and stochastic analysis
, Article Physica A: Statistical Mechanics and its Applications ; Volume 375, Issue 1 , 2007 , Pages 239-246 ; 03784371 (ISSN) ; Reza Rahimi Tabar, M ; Iraji zad, A ; Kavei, G ; Sharif University of Technology
2007
Abstract
The effect of etching time scale of glass surface on its statistical properties has been studied using atomic force microscopy technique. We have characterized the complexity of the height fluctuation of an etched surface by the stochastic parameters such as intermittency exponents, roughness, roughness exponents, drift and diffusion coefficients and found their widths in terms of the etching time. © 2006 Elsevier B.V. All rights reserved
Investigation of vacuum annealing effects on physical-mechanical properties of thermoplastic parts
, Article Materials and Design ; Volume 26, Issue 1 , 2005 , Pages 89-93 ; 02613069 (ISSN) ; Mousavi, S ; Sharif University of Technology
Elsevier Ltd
2005
Abstract
Impact and tensile strength of polystyrene and nylon 6 samples, which have been produced by injection molding before and after annealing in different conditions are obtained. Polystyrene samples that are heated on vacuum conditions can deform highly even in temperatures much less than polystyrene glass temperature. This phenomenon is reduced significantly by heating samples to annealing temperature in atmospheric pressure and then removing air from sample environment in constant temperature. Deformation problems for nylon were not so important but due to high temperature implied for annealing of nylon parts, some color change due to oxidative degradation are observed. So for nylon parts a...
Detection of molecular vibrations of atrazine by accumulation of silver nanoparticles on flexible glass fiber as a surface-enhanced Raman plasmonic nanosensor
, Article Optical Materials ; Volume 128 , 2022 ; 09253467 (ISSN) ; Kordzadeh, A ; Zeinalizad, L ; Sahbafar, H ; Aghanouri, H ; Hadi, A ; Ghaderi, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Surface-Enhanced Raman Spectroscopy (SERS) is a sensitive vibration spectroscopy method applied to analyze a variety of analytes, including toxins and pesticides. The SERS method is an accurate method for detecting significantly low concentrations of biomaterials and chemicals. In the present study, in order to detect atrazine pesticide, the glass fiber substrates coated with silver nanoparticles have been used as SERS plasmonic nanosensors. First, silver nanoparticles were prepared by applying a chemical approach named the Tollens' method, and the SERS plasmonic substrates (SPS) were fabricated by depositing the colloidal silver solution on a glass fiber substrate. The SERS plasmonic...
Synthesis and spectral properties of Nd-doped glass-ceramics in SiO 2-CaO-MgO system prepared by sol-gel method
, Article Journal of Rare Earths ; Volume 31, Issue 6 , 2013 , Pages 595-599 ; 10020721 (ISSN) ; Zohreh, H ; Ali, N ; Sharif University of Technology
2013
Abstract
SiO2-CaO-MgO glass and glass-ceramic powder doped with Nd 3+ were synthesized with sol-gel method. Tetraethylorthosilicate (TEOS), Ca(NO3)2·4H2O, Mg(NO 3)2·6H2O, Nd(NO3) 3·6H2O, ethanol, distilled water, and HNO 3 were used as starting materials. The synthesized powder's properties were examined with simultaneous thermal analysis (STA), X-ray diffraction (XRD), photoluminescence (PL) and scanning electron microscopy (SEM) analysis. The STA curves showed that the softening point and crystallization temperatures were shifted to higher temperatures with increasing dopant content. Regarding XRD patterns of glass samples, Nd was found to act as an intermediate oxide in glass matrix. The XRD...
Molecular dynamics simulation of melting, solidification and remelting processes of aluminum
, Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 36, Issue M1 , 2012 , Pages 13-23 ; 22286187 (ISSN) ; Simchi, A ; Aashuri, H ; Sharif University of Technology
2012
Abstract
A molecular dynamics simulation study has been performed to investigate the solidification and remelting of aluminum using Sutton-Chen many body potential. Different numbers of atoms from 108 to 2048 atoms were considered to find an adequate size for the system. Three different cooling and heating rates, i.e. 10 12 K/s, 10 13 K/s and 10 14 K/s, were used. The structure of the system was examined using radial distribution function. The melting and crystallization temperatures of aluminum were evaluated by calculating the variation of heat capacity during the phase transformation. Additionally, Wendt-Abraham parameters were calculated to determine the glass transition temperature. It is shown...
Effects of ion-exchange and hydrolysis mechanisms on lead silicate glass corrosion
, Article Corrosion ; Volume 68, Issue 9 , September , 2012 , Pages 793-800 ; 00109312 (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
2012
Abstract
Corrosion of lead silicate glass (LSG) contacting 0.5 M aqueous nitric acid (HNO 3) was investigated via scanning electron microscopy, energy-dispersive spectroscopy, inductively coupled plasma analysis, and weight-loss measurement to determine the respective contributions of the ion-exchange vs. the hydrolysis reactions. The LSG having X M ≡ Pb+K+Na/Si mole ratios of less than 0.7 showed very little weight loss with no Si network deterioration. At X M > 0.7, the mechanism changed into the hydrolysis, which caused the formation of a networkless gel layer resting at the solid/liquid interface. Addition of titania (TiO 2) and zirconia (ZrO 2) had disparate effects: X M < 0.7 improved corrosion...
Evaluation of interfacial layer properties in the polystyrene/silica nanocomposite
, Article Journal of Applied Polymer Science ; Volume 119, Issue 4 , August , 2011 , Pages 2039-2047 ; 00218995 (ISSN) ; Farzi, G ; Kalaee, M. R ; Zabihpoor, M ; Sharif University of Technology
2011
Abstract
Processing conditions and final mechanical properties of polymer nanocomposites are affected by their interfacial layers behavior. However, it is impossible to determine directly the properties of these layers by dynamic rheometry tests. In this work, the interfacial layers properties are evaluated for polystyrene containing silica nanoparticles by the concept of glass-transition temperature shift. The samples were prepared via solution-mixing method and dynamic rheometry was used to determine the viscoelastic behavior of filled polymers in the melt state. This initial step showed that addition of silica particles increased the glass-transition temperature. By preference, decrease in the...
Corrosion behavior of ZrO2-SiO2-Al2O3 refractories in lead silicate glass melts
, Article Journal of the European Ceramic Society ; Volume 31, Issue 5 , 2011 , Pages 715-721 ; 09552219 (ISSN) ; Ahmadi, A ; Kakooei, S ; Sadrnezhaad, S. K ; Sharif University of Technology
2011
Abstract
High-temperature (1200-1350°C) corrosion of fused-cast ZrO2-Al2O3-SiO2 (ZAS) refractory contacting lead silicate glass melt (LSG) containing 68.5wt% PbO was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC), x-ray diffraction (XRD), thickness measurement and Archimedes density measurement. ZAS durability was improved by baddeliyete content and deteriorated with open porosity proportion, corundum percentage and eutectic mixture presence. Diffusion of lead resulted in fusion-temperature lowering of the glassy layers embedded within the ZAS particles. Heating caused viscosity drop across the interface, loosening the...
Study of synergistic toughening in a bimodal epoxy nanocomposite
, Article Journal of Reinforced Plastics and Composites ; Volume 34, Issue 4 , February , 2015 , Pages 281-292 ; 07316844 (ISSN) ; Khamesinia, A ; Bagheri, R ; Kouchakzadeh, M. A ; Abadyan, M ; Sharif University of Technology
SAGE Publications Ltd
2015
Abstract
Toughening of epoxy with different types of modifiers produces a bimodal blend that might show better fracture resistance in comparison with single-modified ones. In this research, bimodal epoxy formulations including mixtures of glass microsphere and silica nanoparticles are explored for possible synergistic toughening. The influence of composition on the glass transition temperature (Tg), tensile characteristics, and fracture toughness (KIC) is investigated. Interestingly, a synergism in fracture toughness is observed when mixtures of modifiers were incorporated. For the fixed overall modifier content, KIC is higher when the volume fraction of glass microsphere is lesser than the volume...