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    Effects of drying temperature and aggregate shape on the concrete compressive strength: Experiments and data mining techniques

    , Article International Journal of Engineering Transactions C: Aspects ; Volume 33, Issue 9 , 2020 , Pages 1780-1791 Reza Kashyzadeh, K ; Ghorbani, S ; Forouzanmehr, M ; Sharif University of Technology
    Materials and Energy Research Center  2020
    The main purpose of this paper is to assess the impact of the geometry and size of the aggregate, as well as the drying temperature on the compressive strength of the ordinary concrete. To this end, two aggregates with sharp and round corners were prepared in three different aggregate sizes. After preparing concrete samples, the drying operations were carried out in the vicinity of room temperature, cold wind, and hot wind. Next, the linear relationship between the concrete strength and the studied parameters was estimated using Multiple Linear Regression (MLR) method. Finally, the Taguchi Sensitivity Analysis (TSA) and Decision Tree Analysis (DTA) were applied in order to determine the... 

    Thin-layer drying characteristics and modeling of pistachio nuts

    , Article Journal of Food Engineering ; Volume 78, Issue 1 , 2007 , Pages 98-108 ; 02608774 (ISSN) Kashaninejad, M ; Mortazavi, A ; Safekordi, A ; Tabil, L. G ; Sharif University of Technology
    Thin-layer drying characteristics of pistachio nuts were determined experimentally as a function of temperature, relative humidity and air velocity. Six mathematical models (Page model, modified Page model, exponential model, diffusion model, two term exponential model and Thompson model) for describing the thin-layer drying behavior of pistachio nuts were investigated. Tests were conducted using four air temperatures (25, 40, 55 and 70 °C), three air velocities (0.5, 1.0 and 1.5 m/s) and two levels of relative humidity (5% and 20%) and three replications for each treatment. Out of the six models considered, Page model was found to be the most suitable for describing the drying behavior of... 

    Effects of sucrose, skim milk and yeast powder on survival of lactobacillus rhamnosus gg encapsulated with alginate during one-week storage at room conditions

    , Article Applied Food Biotechnology ; Volume 9, Issue 3 , 2022 , Pages 251-259 ; 23455357 (ISSN) Khodadadi, P ; Tabandeh, F ; Alemzadeh, I ; Soltani, M ; Sharif University of Technology
    National Nutrition and Food Technology Research Institute  2022
    Background and Objective: During the manufacture and storage of probiotic products, there are always possibilities that probiotics be exposed to harmful stresses such as high temperature, low pH, various osmotic pressures and high oxygen levels, which can decrease the number of living cells. Encapsulation is one of the methods used to protect living cells such as probiotic bacteria from environmental challenges. Up-to-date, various compounds with abilities to protect bacteria during freeze-drying and to increase viability during storage have been identified. In this study, alginate with calcium chloride was used to encapsulate probiotic bacteria using extrusion method. Then, effects of... 

    Simultaneous measurements of the resistance and capacitance using a cylindrical sensor system

    , Article Modern Physics Letters B ; Volume 22, Issue 8 , 2008 , Pages 595-610 ; 02179849 (ISSN) Golnabi, H ; Azimi, P ; Sharif University of Technology
    In this article, the design and operation of a cylindrical capacitive sensor based on the dielectric reactance capacitance and conductance changes of the gap medium is reported. The proposed system was used to determine characteristics of different water liquids as a result of the capacitance and resistance variations. The air gap capacitance (dry signal) is measured and then by filling the gap with a liquid, the capacitance (wet signal) is monitored for different liquids. A reported sensor is used for the distilled, tap, boiled, and salt water measurements and the capacitance and resistance results are compared. A big difference of about 38.5 μF in the measured capacitance values for the... 

    Determination of a suitable thin layer drying curve model for saffron (Crocus sativus L) stigmas in an infrared dryer

    , Article Scientia Iranica ; Volume 18, Issue 6 , 2011 , Pages 1397-1401 ; 10263098 (ISSN) Akhondi, E ; Kazemi, A ; Maghsoodi, V ; Sharif University of Technology
    The drying of saffron stigma was investigated in a laboratory infrared dryer. The effect of temperature on the drying rate of samples at various temperatures (60,70...110 °C) was studied. The drying time decreased with an increase in drying air temperature. The constant-rate period is absent from the drying curve. The drying of saffron occurred in the falling rate period. Four, thin-layer drying models, namely, Lewis, Handerson and Pabis, Page, and Midilli and Kucuk, were fitted to drying data. The performance of these models was investigated by comparing the determination of coefficient ( R2) and Root Mean Square Error (RMSE) between the observed and predicted moisture ratios. Among these... 

    Calibrating priestley-taylor model to estimate open water evaporation under regional advection using volume balance method-case study: chahnimeh reservoir, Iran

    , Article Journal of Applied Sciences ; Volume 8, Issue 22 , 2008 , Pages 4097-4104 ; 18125654 (ISSN) Daneshkar Arasteh, P ; Tajrishy, M ; Sharif University of Technology
    The objective of this study is to calibrate Priestley-Taylor (PT) model for estimating open water evaporation from an arid region reservoir called Chahnimeh. Chahnimeh Reservoir which is situated in the Sistan area in the southeast of Iran is being affected by regional energy advection during May to October. Therefore, common models of open water evaporation estimation such as PT require calibration. PT method was calibrated for Chahnimeh Reservoir using a volume balance method. Results showed that PT coefficient, αPT, as a constant over the year varies between 2.47±0.09 and 1.20±0.03 for two different hydrologic conditions of dry and wet. It means that there is also an intra-annular... 

    Effect of drying methods on quality of Pistachio nuts

    , Article Drying Technology ; Volume 21, Issue 5 , 2003 , Pages 821-838 ; 07373937 (ISSN) Kashani Nejad, M ; Tabil, L. G ; Mortazavi, A ; Safe Kordi, A ; Sharif University of Technology
    Marcel Dekker Inc  2003
    The effect of various methods of drying (sun drying, bin drying, vertical continuous drying, vertical cylindrical drying, and funnel cylindrical drying) on moisture content, lipid quality (peroxide value, thiobarbituric acid value, and free fatty acids), sensory attributes (firmness, sweetness, rancidity, roasted flavor, split shell, shell appearance, and overall palatability), and percent split shell of pistachio nuts (Pistacia vera L.) were studied. Sun drying and bin drying resulted in higher split shell percent on pistachio nuts than other drying methods. The different drying methods used in this study did not have any significant influence on the free fatty acids, peroxide value, and... 

    Optimal in-depth trapping by tuning the correction collar of a dry objective lens

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 39, Issue 12 , 2022 , Pages 3209-3215 ; 07403224 (ISSN) Gorjizadeh Alinezhad, H ; Mahdavi, S. M ; Reihani, S. N. S ; Sharif University of Technology
    Optica Publishing Group (formerly OSA)  2022
    Optical tweezers are proven and indispensable micro-manipulation tools. It is very common to use an immersion-assisted high NA objective for optical trapping of micrometer-sized beads. However, such objectives suffer from low working depth range. Here we show, both by theory and experiment, that a dry objective can be utilized for optimal trapping of even sub-micrometer objects. For the first time, to the best of our knowledge, we were able to stably trap polystyrene beads with radii of 270 and 175 nm in 3D using an objective with numerical aperture of 0.9. © 2022 Optica Publishing Group  

    Analytical and Experimental Study of Transverse Vibration of Ulerr-Bernoulli Beam with Dry Friction Boundary Condition

    , M.Sc. Thesis Sharif University of Technology Kavyanpoor, Mobin (Author) ; Dehghani Firouzabadi, Roohollah (Supervisor)
    The dry friction and its effect on the dynamics and vibrations of structures have always been one of the remarkable engineering issues. In the structures of engineering, dry friction mostly exists at the joints of structures and substrates and dry friction can lead to the nonlinearity and even chaos in the vibration of structures. There are different theories for the friction modeling and the most famous theory is the relation between the proportional ratio of the force of friction and perpendicular force to the surface. The main characteristic of friction as a damper force is the change of direction along with change in the direction of velocity. In the present study, at first, the nature... 

    Experimental and theoretical investigation of drying of Green Peas in a Fluidized Bed Dryer of inert particles assisted by Infrared heat source

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 32, Issue 1 , 2013 , Pages 83-94 ; 10219986 (ISSN) Honarvar, B ; Mowla, D ; Safekordi, A. A ; Sharif University of Technology
    Drying of green peas in a Fluidized Bed Dryer (FBD) with inert particle, heated by combined sources of hot air and InfraRed (IR) radiation, has been experimentally and theoretically studied. For this purpose, an experimental set up was constructed. This setup was composed of a cylindrical bed dryer containing some inert particles which are fluidized by hot air. Some infrared lamps were also placed around the bed for heating assistance. A sample of green pea was hung in the fluidized bed and its moisture content, surface and central temperature were measured with time. A mathematical model, based on the two layers concept of penetration and conduction was also proposed for this process. The... 

    Calculating leakage inductances of split-windings in dry-type traction transformers

    , Article Transactions on Electrical Engineering, Electronics, and Communications ; Volume 10, Issue 1 , 2012 , Pages 17-24 ; 16859545 (ISSN) Azizian, D ; Vakilian, M ; Faiz, J ; Bigdeli, M ; Sharif University of Technology
    Calculating leakage inductances between windings of multi-winding traction transformers is one of the most important schemes in design procedure. In this paper, a new analytical method and finite element models have been introduced for electromagnetic modeling of traction transformers with four split windings. Using these methods, the leakage inductances between the split windings are calculated and the methods have been validated with the help of experimental data gathered from a typical 4000kVA cast-resin dry-type transformer. Some reformations are employed to improve the finite element results and effects of these reformations on accuracy of the models are studied. Employing the validated... 

    Moisture diffusivity and shrinkage of broad beans during bulk drying in an inert medium fluidized bed dryer assisted by dielectric heating

    , Article Journal of Food Engineering ; Volume 92, Issue 3 , 2009 , Pages 331-338 ; 02608774 (ISSN) Hashemi, G ; Mowla, D ; Kazemeini, M ; Sharif University of Technology
    Drying behavior of broad beans (Vicia faba) was studied in a pilot scaled fluidized bed dryer with inert particles assisted by dielectric heating. The effective diffusion coefficient of moisture transfer was determined by Fickian method at four different air drying temperatures of 35, 45, 55 and 65 °C. Correlations for moisture diffusivity as a function of moisture content and temperature of the drying medium were developed. The values of moisture diffusivity were obtained within the range of 1.27 × 10-9-6.48 × 10-9 m2/s and the activation energies for FBD and FBD + DE were found to be 27.71 and 17.10 kJ/mol, respectively. The shrinkage behavior of the broad beans was also investigated by... 

    Suppression of torsional vibrations in drilling systems by using the optimization-based adaptive back-stepping controller

    , Article International Journal of Mechanics and Control ; Volume 20, Issue 1 , 2019 , Pages 105-110 ; 15908844 (ISSN) Tashakori, S ; Fakhar, M ; Sharif University of Technology
    Levrotto and Bella  2019
    Stick-slip oscillations are one of the main sources of system failure and bit damage in a rotary drilling system. Thus, suppressing such vibrations is of great importance. There are different modelling approaches demonstrating drill string dynamics, among which lumped parameter models are more common in control studies due to faster computations. Since the system dynamic includes uncertain terms, in this paper an adaptive back-stepping controller is proposed. To tune controller gains, particle swarm optimization algorithm has been employed which guarantees a better control performance. The simulation results demonstrate the feasibility of the designed controller. The results have been also... 

    Simulation of thermal profile in a single pellet during drying process with CFD method

    , Article Proceedings of the 24th International Mining Congress of Turkey, IMCET 2015, 14 April 2015 through 17 April 2015 ; 2015 , Pages 797-803 ; 9786050107050 (ISBN) Gitiara, A ; Namehi, A ; Vali, H ; Shahrokhshahi, H. R ; Soltani, H ; Alamdari, E. K ; Cheraghi, A ; Karadeniz, M ; Gulsun Kilic, M ; Torun Bilgic, E ; Basarir, H ; Onel, O ; Sharif University of Technology
    TMMOB Maden Muhendisleri Odasi  2015
    Green iron oxide pellets are indurated with thermal treatment in pelletizing plant to achieve sufficient mechanical properties and to be used in iron-steel industry. In the first stage, the pellets are dried with hot air coming from the firing unit. High heat transfer makes the evaporation rate exceeding the outgoing steam rate from the pellets and as a result, increasing the inner pressure of the pellets and fragment. On the other hand, low heat transfer causes low production rate. Using the related equations and considering the pellets' moisture and porosity and applying the pellets' condition on parameters such as specific heat capacity and heat conductivity, an acceptable standard is... 

    Preparation of biodegradable gelatin/PVA porous scaffolds for skin regeneration

    , Article Artificial Cells, Nanomedicine and Biotechnology ; 2016 , Pages 1-8 ; 21691401 (ISSN) Mahnama, H ; Dadbin, S ; Frounchi, M ; Rajabi, S ; Sharif University of Technology
    Taylor and Francis Ltd  2016
    Porous scaffolds composed of gelatin/poly (vinyl alcohol), (Gel/PVA), were prepared using combination of freeze gelation and freeze drying methods. The effect of polymer concentration, gelatin/PVA ratio, and glutaraldehyde/gelatin ratio (GA/Gel) was investigated on morphology of pores, swelling ratio, biodegradation, and skin cell culture. At optimum preparation conditions the scaffolds had uniform pore size distributions showing high swelling ratio of 23.6. The scaffolds were of biodegradable nature and almost degraded in 28 days. Human dermal fibroblast cells (HDF) were cultured on the scaffolds and MTS assay was conducted to evaluate the influence of PVA on growth and proliferation of the... 

    The Study of Wind Aerodynamics Effects on Degrading the Dry Cooling Tower Performance; Using Experimental and CFD Tools

    , M.Sc. Thesis Sharif University of Technology Bagheri, Amir Hossein (Author) ; Darbandi, Massoud (Supervisor)
    A power plant cooling tower is like a tower, which needs to be studied very carefully from the aerodynamics point of view. Both the aerodynamics forces on the plume and intake stram are affected by the local winds and the performance of cooling tower decreases. There is a symmetric turbulent flow through the cooling tower if there is no. Wind blowing creates different vorticies, which appear in the lower section of the tower. Their periodic and wuick movments causes deficiency in towers performance and efficiency. Additionally there is wind effect on the plane of cooling tower and this causes a chocked plume which is named Wind Cover. The objective of this study is to decrease the adverse... 

    Thermal Analysis of Dry Friction Clutch and its Effect in Torque Transmission

    , M.Sc. Thesis Sharif University of Technology Hasanpour, Hadi (Author) ; Kazemzadeh Hannani, Siamak (Supervisor)
    For optimum designing of dry friction clutch, we should taking into account a lot of parameters, in order to the clutch have good efficiency in torque transmission and power train. These parameters include: the type of friction plate and the mechanical properties, Clutch geometry, diaphragm spring and its ability to make pressure. In this project, the goal is the analysis of effect of different parameters in clutch's temperature distribution and effect of these issues in torque transmission. In next step, the clutch's temperature distribution analyzed by changing the friction plate (ceramic), pressure applied and relative round in order to gain optimum properties of clutch. These works done... 

    Effects of Fluctuation in Urmia Lake Water Level on Local Climate of Basin

    , M.Sc. Thesis Sharif University of Technology Dehghanipour, Amir Hossien (Author) ; Tajrishi, Masoud (Supervisor)
    Saline and fresh water lakes comprise a high proportion of the surface water resources and take effects from climate, hydrological, geomorphological changes and human activities in their basins. Variation in area of lakes causes changes in weather and local climate of their basins. Due to high environmental value of lakes and their particular effects on the ecosystem of the region, they have been always center of attention. Lake Urmia as the greatest lake in IRAN and the second largest saline lake in the world always has been considered by many researchers. In recent years Lake Urmia has had many changes such as decrease in area and level. Various factors such as climate change, periodic... 

    Fabrication of Nano Structure Tialite-fibroin Scaffold

    , M.Sc. Thesis Sharif University of Technology Hajseyedjavadi, Mahdieh (Author) ; Maddah Hosseini, Hamid Reza (Supervisor)
    The development of novel three dimensional degradable porous scaffolds is of great interest for tissue engineering.silk ibroin has recently received intensive attention as a material for use in fabrication of 3D porous scaffolds beacuse of its excellent biocompatibility, physical and mechanical properties, and easy processibility. However, silk alone has no osteoinductive property and considerebely lower mechanical properties than native bone. In order to overcome this limitation silk fibroin can be combined with other materials.the properties of scaffold can be significantly improved and new features can be endowed by the second ccomposition. The present study deals with fabrication of... 

    Fabrication of aluminum nitride coatings by electrophoretic deposition: Effect of particle size on deposition and drying behavior

    , Article Ceramics International ; Volume 37, Issue 1 , 2011 , Pages 313-319 ; 02728842 (ISSN) Abdoli, H ; Zarabian, M ; Alizadeh, P ; Sadrnezhaad, S. K ; Sharif University of Technology
    Electrophoretic technique was used to deposit micro- and nano-sized aluminum nitride coatings on stainless steel surfaces by using a well-dispersed stable suspension produced by addition of AlN powder plus a small amount of iodine to ethanol. Parabolic regime governed the deposition. Electrophoretic deposition for 240 s at 100 V resulted in formation of a uniformly dense film on the top, but a porous inhomogeneous layer at the bottom. This was attributed to fast deposition of coarse particles and/or agglomerates at large electric fields. After drying, micro-sized particles led to a uniform crack-free interface while nano-particles resulted in fragmented non-cohesive layers. Weight loss...