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    The impact of long-term curing period on the mechanical features of lime-geogrid treated soils

    , Article Geomechanics and Geoengineering ; 19 March , 2020 Jahandari, S ; Mojtahedi, S. F ; Zivari, F ; Jafari, M ; Mahmoudi, M. R ; Shokrgozar, A ; Kharazmi, S ; Vosough Hosseini, B ; Rezvani, S ; Jalalifar, H ; Sharif University of Technology
    Taylor and Francis Ltd  2020
    Abstract
    One problem that has always been a challenge for geotechnical engineers is construction on problematic and soft soils. Traditional methods of lime and cement stabilisation can be used to treat soils with these properties. The main drawback of lime addition to the clayey soils is a significant loss in ductility of lime-treated soils. Using ductile materials such as geogrids in lime-treated soils is one of the most effective ways to increase the soil ductility. Therefore, the effect of geogrids and lime on unconfined compressive strength (UCS), failure strain (ɛf), secant modulus (Es), deformability indexes (ID), resilient modulus (Mr), bulk modulus (K), and shear modulus (G) of the treated... 

    Triaxial behaviour of a cemented gravely sand, Tehran alluvium

    , Article Geotechnical and Geological Engineering ; Volume 21, Issue 1 , 2003 , Pages 1-28 ; 09603182 (ISSN) Asghari, E ; Toll, D. G ; Haeri, S. M ; Sharif University of Technology
    2003
    Abstract
    Cemented coarse-grained alluvium is present in a vast area of Tehran city. Iran including its suburbs. This deposit consists of gravely sand to sandy gravel with some cobbles and is dominantly cemented by carbonaceous materials. In order to understand the mechanical behaviour of this soil, a series of triaxial compression tests were performed on uncemented, artificially cemented and destructured samples. Hydrated lime was used as the cementation agent for sample preparation to model the Tehran deposit. The tests were performed on cemented samples after an appropriate time for curing. The tests on cemented samples show that a shear zone appears as the shear stress approaches the peak shear... 

    The impact of long-term curing period on the mechanical features of lime-geogrid treated soils

    , Article Geomechanics and Geoengineering ; Volume 17, Issue 1 , 2022 , Pages 269-281 ; 17486025 (ISSN) Jahandari, S ; Mojtahedi, S. F ; Zivari, F ; Jafari, M ; Mahmoudi, M. R ; Shokrgozar, A ; Kharazmi, S ; Vosough Hosseini, B ; Rezvani, S ; Jalalifar, H ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    One problem that has always been a challenge for geotechnical engineers is construction on problematic and soft soils. Traditional methods of lime and cement stabilisation can be used to treat soils with these properties. The main drawback of lime addition to the clayey soils is a significant loss in ductility of lime-treated soils. Using ductile materials such as geogrids in lime-treated soils is one of the most effective ways to increase the soil ductility. Therefore, the effect of geogrids and lime on unconfined compressive strength (UCS), failure strain (ɛf), secant modulus (Es), deformability indexes (ID), resilient modulus (Mr), bulk modulus (K), and shear modulus (G) of the treated... 

    The effects of a hydrochloric acid pre-treatment on the physicochemical properties and pozzolanic performance of rice husk ash

    , Article Cement and Concrete Composites ; Volume 39 , 2013 , Pages 131-140 ; 09589465 (ISSN) Gholizadeh Vayghan, A ; Khaloo, A. R ; Rajabipour, F ; Sharif University of Technology
    2013
    Abstract
    This paper investigates the effects of acid normality (0.01-6 N HCl) and combustion retention time (0.25- 16 hours) on the pozzolanic properties of pre-combustion acid-treated rice husk ash. The pozzolanic reactivity was quantified by adding ground ash to saturated Ca(OH)2 solutions and monitoring the time-dependent electrical conductivity and pH of the solutions. Also, the strength activity of ashes from different processes was measured by testing the compressive strength of mortars. It was observed that acid treatment results in ashes with higher SiO2 content, lower alkali and unburned carbon content, better grindability, and smaller particle size, in comparison with ash from non-acid... 

    Effects of substrate material and annealing temperature on morphology of zinc oxide films

    , Article Materials Science and Technology ; Volume 22, Issue 3 , 2006 , Pages 308-314 ; 02670836 (ISSN) Vaezi, M. R ; Sadrnezhaad, S. K ; Sharif University of Technology
    2006
    Abstract
    A two stage chemical deposition (TSCD) technique is used to produce ZnO films on quartz glass (QG), soda lime glass (SLG) and high purity alumina (HPA) from an aqueous solution of zinc complex. The effects of the substrate material on the chemical composition and morphology of the deposited layer are investigated. The effects of different annealing temperatures (180, 300, 500 and 800°C) on the morphology and orientation of the ZnO crystallites are also determined. X-ray diffraction diffractograms show that above 300°C, the intensity of (002) peak considerably decreases with increasing temperature. Results indicate that changing the substrate from QG to SLG does not significantly influence... 

    Effects of saturation degrees, freezing-thawing, and curing on geotechnical properties of lime and lime-cement concretes

    , Article Cold Regions Science and Technology ; Volume 160 , 2019 , Pages 242-251 ; 0165232X (ISSN) Jahandari, S ; Saberian, M ; Tao, Z ; Mojtahedi, S.F ; Li, J ; Ghasemi, M ; Rezvani, S. S ; Li, W ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    There are very limited researches carried out to investigate the influence of saturation degrees, freezing-thawing, and curing times on geotechnical properties of lime concrete (LC) and lime-cement concrete (LCC) due to the capillary action and changes in groundwater table. Subsequently, the primary goal of this research is to investigate the influence of these parameters on mechanical properties of LC and LCC using unconfined compression tests, namely uniaxial compressive strength (UCS), stress-strain behavior, deformability index (I D ), secant modulus (E S ), failure strain, bulk modulus (K), resilient modulus (M R ), brittleness index (I B ), and shear modulus (G). At first, the... 

    Characterization of optical properties of amorphous BaTiO3 nanothin films

    , Article Journal of Non-Crystalline Solids ; Volume 355, Issue 50-51 , 2009 , Pages 2480-2484 ; 00223093 (ISSN) Ashiri, R ; Nemati, A ; Sasani Ghamsari, M ; Aadelkhani, H ; Sharif University of Technology
    Abstract
    Amorphous barium titanate nanothin films were prepared by sol-gel dip-coating method. According to transmission spectrum, the refractive index and optical band gap of nanothin films have been determined. High transmission spectrum without any fluctuation in visible wavelength region was recorded. Experimental results indicated that the surface morphology of prepared nanothin films were improved and as a result of that, a better optical properties, less optical losses and higher band gap width were obtained in contrast with other reported data. It was found that optical propagation loss of BaTiO3 nanothin film was much lower than normal polycrystalline BaTiO3 thin film. It seems to us that,... 

    AlV Alloy by Aluminothermic Reduction of Vanadium Pentoxide

    , M.Sc. Thesis Sharif University of Technology Saboor Bagherzadeh, Elahe (Author) ; Halali, Mohammad (Supervisor)
    Abstract
    In the present work, aluminothermic reduction of vanadium pentoxide have been used to produce aluminium vanadium alloys. The effect of addition of lime and excess aluminium on the produced alloy was studied. The experiments were carried out in air and in argon. The alloys microstructure were analyzed bu light and scanning electron microscopy. Other methods such as XRD, XRF, ICP, AAS and titration were employed to analyzed the alloy and the slag. It was found that the addition of lime and excess aluminium increase the yield of the alloy. Vanadium recovery was not affected by the atmosphere used.
     

    Effect of Hydrated Lime on Performance Properties of Hot Mix Asphalt

    , M.Sc. Thesis Sharif University of Technology Nabizadeh Shahri, Hadi (Author) ; Tabatabaee, Nader (Supervisor)
    Abstract
    Hydrated lime has been used as an anti-stripping agent with acceptable performance. Numorous studies have been conducted to evaluate hydrated lime as an anti-stripping agent, however effect of hydrated lime on performance properties of asphalt mixture has not been fully addressed. In the present study, the effect of hydrated lime was investigated. In this study, three methods of adding hydrated lime were evaluated. These methods consist of a) adding dry hydrated lime to dry aggregates, b) adding hydrated lime to the binder to form mastic, and c) adding slurry lime to dry aggregates.
    More uniform distribution of hydrated lime on aggregate surface in the slurry method improved performance... 

    Two-stage chemical deposition of oxide films

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 21, Issue 1 , 2008 , Pages 65-70 ; 1728-144X (ISSN) Vaezi, M. R ; Sadrnezhaad, S. K ; Sharif University of Technology
    Materials and Energy Research Center  2008
    Abstract
    Two-stage chemical deposition (TSCD) technique is used to produce ZnO, Mn2O3 and NiO films on soda-lime glass (SL-G) from an aqueous solution of zinc, manganese and nickel complex, respectively. The TSCD method enables the deposition of metal oxide thin films with a thickness which can be controlled during the preparation procedure. The ZnO, Mn 2O3 and NiO thin films were polycrystalline films which were adherent well to the substrates. The SEM micrographs clearly indicate that the zinc oxide layer is composed of oval shaped crystallites preferably orientated perpendicular to the surface of the substrate. The Mn 2O3 and NiO layers were closely packed on the substrate. These particles seem to... 

    Simulation of windscreen bending using viscoplastic formulation

    , Article Journal of Materials Processing Technology ; Volume 170, Issue 1-2 , 2005 , Pages 298-303 ; 09240136 (ISSN) Parsa, M. H ; Rad, M ; Shahhosseini, M. R ; Shahhosseini, M. H ; Sharif University of Technology
    2005
    Abstract
    Soda-lime glass material has been widely used for automobile windscreens. Two commercial finite element programs have been evaluated for simulation of the creep forming process using isotropic viscoplastic behavior assumption for soda-lime glass. This was done by selecting one of the programs and using it in connection with an optimization program for controlling the glass surface temperature, to examine the effect of considering thermal stresses and temperature variations along the surface of glass sheet for obtaining desired geometrical shape. The results show that the thermal stress effect must be considered for achieving more accurate simulation of glass creep forming process. Also... 

    Effects of moisture on warm mix asphalt containing Sasobit

    , Article Scientia Iranica ; Volume 24, Issue 4 , 2017 , Pages 1866-1873 ; 10263098 (ISSN) Nabizadeh, H ; Naderi, B ; Tabatabaee, N ; Sharif University of Technology
    Sharif University of Technology  2017
    Abstract
    The asphalt industry has been at the forefront of sustainable development. Warm Mix Asphalt (WMA) has been developed to cope with issues such as high energy prices and air pollution. These mixes require less energy and generate fewer pollutants during production in comparison with conventional Hot Mix Asphalt (HMA). Although a promising technology, the durability of WMA is not clear because long-term WMA field performance data is limited. This study investigated the susceptibility of Sasobit-modified WMA to moisture, since moisture damage is a major cause of premature pavement failure in asphalt concrete. To this end, WMA samples were made using different concentrations of Sasobit and the... 

    Performance evaluation of slurry seals containing reclaimed asphalt pavement

    , Article Transportation Research Record ; Volume 2673, Issue 1 , 2019 , Pages 358-368 ; 03611981 (ISSN) Saghafi, M ; Tabatabaee, N ; Nazarian, S ; Sharif University of Technology
    SAGE Publications Ltd  2019
    Abstract
    Preventive pavement maintenance methods such as slurry seals are cost-effective treatments that increase the longevity of pavements. The incorporation of recycled materials such as reclaimed asphalt pavement (RAP) into asphalt pavement helps to further reduce costs and energy consumption. The present research studied the feasibility of incorporating RAP into slurry seal mixtures or RAP slurry seals. Two slurry seal mixtures containing cement and hydrated lime as fillers were tested. The first mixture comprised slurry seal made with virgin aggregate and the second used RAP as the aggregate. The wet track abrasion test (WTAT) and loaded wheel test (LWT) were conducted to evaluate the... 

    Pure sulfide Cu2ZnSnS4 layers through a one-step low-temperature PLD technique: Insight into simulation on modified back contact to overcome the barrier of MoS2

    , Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 262 , 2020 Heidariramsheh, M ; Haghighi, M ; Dabbagh, M. M ; Mahdavi, S. M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Targeting on the selenium free, pure sulfide kesterite compound (CZTS) allows retention of the higher band gap nontoxic absorber for a single-junction solar cell. In this work, CZTS thin films were deposited by the PLD method and the Structural/optical properties, as well as Mott–Schottky analysis, were studied at different substrate temperatures. Without undergoing the sulfurization process, the single-phase CZTS thin film is prepared at 300 ℃. In the second step, a numerical simulation is performed using the solar cell capacitance simulator to study the effect of the grading layer of MoS(Se)2 on the rear side of pure sulfide kesterite based solar cells. The device with a MoSe2 coated... 

    A Study on Optoelectronic Properties of Copper Zinc Tin Sulfur Selenide: A Promising Thin-Film Material for Next Generation Solar Technology

    , Article Crystal Research and Technology ; Volume 56, Issue 7 , 2021 ; 02321300 (ISSN) Ali, N ; Zubair, M ; Khesro, A ; Ahmed, R ; Uddin, S ; Shahzad, N ; Alrobei, H ; Kalam, A ; Al-Sehemi, A. G ; Ul Haq, B ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    Abstract
    Studies on copper zinc tin sulpher selenide (CZTSSe) thin-film material and its applications as a base material are intensively being researched since it is an earth-abundant, inexpensive, flexible, and interesting material for next-generation optoelectronic technologies. Apropos, this study explores and reports the synthesis of CZTSSe thin films and their key optoelectronics characteristics. The reported films are fabricated on a soda-lime glass substrate by using a physical vapor deposition technique, and then annealed from 250 to 450 °C. From the X-ray diffraction analysis, the structure of the as-deposited thin films is found to be amorphous in nature. Annealed thin films of CZTSSe... 

    A study on optoelectronic properties of copper zinc tin sulfur selenide: A promising thin-film material for next generation solar technology

    , Article Crystal Research and Technology ; Volume 56, Issue 7 , 2021 ; 02321300 (ISSN) Ali, N ; Zubair, M ; Khesro, A ; Ahmed, R ; Uddin, S ; Shahzad, N ; Alrobei, H ; Kalam, A ; Al Sehemi, A. G ; Ul Haq, B ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    Abstract
    Studies on copper zinc tin sulpher selenide (CZTSSe) thin-film material and its applications as a base material are intensively being researched since it is an earth-abundant, inexpensive, flexible, and interesting material for next-generation optoelectronic technologies. Apropos, this study explores and reports the synthesis of CZTSSe thin films and their key optoelectronics characteristics. The reported films are fabricated on a soda-lime glass substrate by using a physical vapor deposition technique, and then annealed from 250 to 450 °C. From the X-ray diffraction analysis, the structure of the as-deposited thin films is found to be amorphous in nature. Annealed thin films of CZTSSe... 

    Evaporation mitigation assessment by self-assembled nano-thickness films in shallow fresh water lake using fixed and semi-floating pans

    , Article Environmental Processes ; Volume 9, Issue 3 , 2022 ; 21987491 (ISSN) Nejatian, A ; Mohammadi, M ; Doulabi, M ; Iraji zad, A ; Tajrishy, M ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    Controlling evaporation plays an essential role in arid and semi-arid water resources systems where it accounts for a considerable amount of reservoirs outflow. In this study, we have evaluated evaporation reduction efficiency of different kinds of self-assembled nano-thickness films. The films consist of six different combinations of stearyl and cetyl alcohols with additives such as jojoba oil, stearic acid, and calcium hydroxide. The study lasted from July to August and utilized two pairs of class A evaporation pans: one pair was semi-floating on Chitgar lake water surface while the other one was located on the shore. The experimental results showed that a monolayer containing 3:1 stearyl... 

    Design and Laboratory Evaluation of Slurry Seal Mixes

    , M.Sc. Thesis Sharif University of Technology Saghafi, Mahdi (Author) ; Tabatabaee, Nader (Supervisor)
    Abstract
    Pavement preventive maintenance methods such as slurry seals are cost-effective treatments that enhance pavement longevity. Incorporation of recycled materials such as reclaimed asphalt pavement (RAP) into asphalt pavements helps further reduce costs and energy consumption. Because the use of emulsions and pavement preventive methods is uncommon in Iran, there is little experience with the technology in this area. The present study designed and developed slurry seal and emulsion test devices at Sharif University lab to study the feasibility of incorporation of RAP into slurry seal mixtures while respecting the limits specified by the ISSA and ASTM. Two slurry seal mixtures in which cement... 

    Characterization of RAP Binder and Warm Mix Asphalt Containing High RAP Percentage and Crumb Rubber

    , M.Sc. Thesis Sharif University of Technology Morsali, Atefeh (Author) ; Tabatabaei, Nader (Supervisor)
    Abstract
    Increased environmental concerns and high oil prices have encouraged highway agencies to maximize the use of recycled materials like Reclaimed Asphalt Pavements (RAP) in pavement construction. However, utilization of RAP has limited to low percentage, generally less than 25%. This is due aged, stiffer, and less strain tolerant asphalt binder in RAP. As the RAP proportion increases, a large amount of the aged binder will be introduced into the mixture. The excessive stiffness of HMA mixture tends to lead to less workable mixture. Studies were conducted to examine the effect of Sasobit on the workablility of high RAP mixtures. The results indicated while the utilization of Sasobit had improved... 

    Growth of Na0.3WO3 nanorods for the field emission application

    , Article Journal of Physics D: Applied Physics ; Volume 42, Issue 20 , 2009 ; 00223727 (ISSN) Azimirad, R ; Khademi, A ; Akhavan, O ; Zaker Moshfegh, A. R ; Sharif University of Technology
    2009
    Abstract
    Na0.3WO3 1D nanostructure forms (nanorods and nanobelts) were grown by a solid-liquid-solid mechanism from a 40 nm sputtered tungsten film deposited on a soda-lime substrate and annealed at 700 °C in a tubular furnace in N2 ambient. The morphology, structure, composition and chemical state of the prepared nanostructures were characterized by SEM, XRD, TEM, SAED and XPS measurements. The Na0.3WO3 1D nanostructures were found to have a cubic crystalline structure and grown along the [0 0 1] direction. The nanorods are a few micrometres in length and about 50 nm in diameter. The field-emission application of the prepared samples at different distances between the cathode and the anode was...