Search for: laboratory-method
0.006 seconds

    Growth and damping of interfacial waves on a diffuse interface

    , Article Environmental Fluid Mechanics ; Volume 16, Issue 2 , 2016 , Pages 401-412 ; 15677419 (ISSN) Fazeli, M ; Jamali, M ; Lawrence, G. A ; Seymour, B ; Sharif University of Technology
    The resonant interaction of surface and internal waves produces a nonlinear mechanism for energy transfer among wave components in oceans, lakes, and estuaries. In many field situations, the stratification may be well approximated by a two-layer fluid with a diffuse interface. The growth and damping rates of sub-harmonic interfacial waves generated by a surface wave through a three-wave resonant interaction are measured in the laboratory. These measurements are compared with theoretical predictions. A diffuse interface reduces the damping rate and increases the growth rate. The predicted growth rate provides excellent comparison with the laboratory measurements. The inclusion of the effects... 

    Experimental investigation of steel frames with single bays of symmetrical y-shaped concentric bracings

    , Article Scientia Iranica ; Volume 19, Issue 2 , 2012 , Pages 195-210 ; 10263098 (ISSN) Majid Zamani, S ; Vafai, A ; Aghakouchak, A. A ; Kazemi, M. T ; Sharif University of Technology
    To obtain wider openings than those provided by Chevron bracing, the braces are cranked and connected to the frame corner by an additional brace to form double y-shaped bracings. However, y-bracings are prone to instability and out of plane buckling, accompanied by low hysteretic energy absorption. An experimental research program, focused on y-bracing, was conducted at the BHRC structural engineering laboratory. Specimens presented in this paper include three full-scale single bay frames, with symmetric y-bracing of different cross sections and connection types. In addition, one specimen with Chevron bracing was tested as a reference. A quasi-static cyclic loading was applied increasingly... 

    The prediction of the density of undersaturated crude oil using multilayer feed-forward back-propagation perceptron

    , Article Petroleum Science and Technology ; Volume 30, Issue 1 , 2011 , Pages 89-99 ; 10916466 (ISSN) Rostami, H ; Shahkarami, A ; Azin, R ; Sharif University of Technology
    Crude oil density is an important thermodynamic property in simulation processes and design of equipment. Using laboratory methods to measure crude oil density is costly and time consuming; thus, predicting the density of crude oil using modeling is cost-effective. In this article, we develop a neural network-based model to predict the density of undersaturated crude oil. We compare our results with previous works and show that our method outperforms them  

    Effects of temperature and mixing modes on the performance of municipal solid waste anaerobic slurry digester 09 Engineering 0907 Environmental Engineering 09 Engineering 0904 Chemical Engineering

    , Article Journal of Environmental Health Science and Engineering ; Volume 17, Issue 2 , 2020 , Pages 1077-1084 Babaei, A ; Shayegan, J ; Sharif University of Technology
    Springer  2020
    Purpose: Anaerobic digestion is a promising technology for simultaneous treatment of biodegradable organic matter of municipal solid waste (MSW) and production of renewable energy. Mixing modes and temperature have influences on biogas production in anaerobic digesters treating MSW. Therefore, in this study, digester was operated at different modes of mixing and temperatures to obtain design criteria. Methods: The experiments were carried out in a semi-continuous digester. In the first part of the investigation, temperature was set at 25, 28, 31 and 34 °C. During this step, digester content was mixed in an intermittent mode by mechanical mixers. In the second part of the study, mixing... 

    A new and applicable method to calculate mass and heat transfer coefficients and efficiency of industrial distillation columns containing structured packings

    , Article Energy ; Volume 36, Issue 3 , 2011 , Pages 1415-1423 ; 03605442 (ISSN) Sadeghifar, H ; Safe Kordi, A. A ; Sharif University of Technology
    Most of the methods developed for efficiency estimation of distillation columns were based on the empirical mass transfer and hydraulic relations correlated to laboratory data. Therefore, these methods cannot estimate efficiency of industrial columns with sufficient accuracy. In this paper, a new and applicable method was developed for calculation of efficiency (and mass and heat transfer coefficients) of distillation columns containing structured packings. This method has potential advantages; e.g., it can calculate efficiency without using any empirical mass transfer and hydraulic correlations and models, and without the need to estimate the operational and hydraulic parameters of column.... 

    Experimental study of fuel regression rate in an HTPB/N2O hybrid rocket motor

    , Article Scientia Iranica ; Volume 25, Issue 1 , 2018 , Pages 253-265 ; 10263098 (ISSN) Rezaei, H ; Soltani, M. R ; Mohammadi, A. R ; Sharif University of Technology
    Sharif University of Technology  2018
    The performance of an HTPB/N2O hybrid motor was experimentally investigated. A hybrid motor was designed and manufactured in a laboratory with the purpose of studying the effects of various parameters on the motor's performance, including fuel regression rate and specific impulse. A series of tests were conducted to find a correlation between the fuel regression rate and the oxidizer's mass flux. The effects of chamber's pressure on the regression rate as well as other performance parameters were investigated. While the burning rate did not change dramatically, both the efficiency and ISP of the motor increased. The local fuel regression rate and the fuel port were also calculated. In... 

    Educational robot for principles of electrical engineering

    , Article Scientia Iranica ; Volume 25, Issue 3D , 2018 , Pages 1582-1592 ; 10263098 (ISSN) Rahnavard, M ; Alavi, M. H ; Khorasani, S ; Vakilian, M ; Fardmanesh, M ; Sharif University of Technology
    Sharif University of Technology  2018
    An educational robot is described, which is designed and constructed for use in the laboratory of Principles of Electrical Engineering. The discrete nature of design, conforming to a simple block strategy, allows for fairly easy introduction of basic and fundamental concepts of Electrical Engineering to the freshman students, including control, actuation, wireless signal transmission, and analogue/digital conversions. Each block or module represents one or few engineering ideas and helps the students to understand the interplay and connection between system divisions, and enhance their creative thinking. Circuits are designed and implemented such that both structure and functionality of each... 

    Harmful algal blooms (red tide): a review of causes, impacts and approaches to monitoring and prediction

    , Article International Journal of Environmental Science and Technology ; Volume 16, Issue 3 , 2019 , Pages 1789-1806 ; 17351472 (ISSN) Zohdi, E ; Abbaspour, M ; Sharif University of Technology
    Center for Environmental and Energy Research and Studies  2019
    Red tide, an impermanent natural phenomenon including harmful algal blooms, causes changing the color of the sea generally to red or almost brown, and has a serious impact on environment along the coast and aquatic ecosystem. Due to recent extensive steady harmful algal blooms events that cause adverse impacts on human healthsome, aquaculture and tourism industry, and the entire economy of the coastal region, the need of society for realizing these phenomena is much greater than the past. In the recent decades, consideration of algal blooms and determination of bloom-former species and fundamental researches about dynamics of blooms are increased worldwide. Development in technology has... 

    Experimental observation of the flow structure of turbidity currents

    , Article Journal of Hydraulic Research ; Volume 49, Issue 2 , 2011 , Pages 168-177 ; 00221686 (ISSN) Nourmohammadi, Z ; Afshin, H ; Firoozabadi, B ; Sharif University of Technology
    The structure of turbidity currents released on a sloping bed below fresh water is investigated. Kaolin is used as a suspended material. Laboratory observations indicate that if a dense layer moves through the channel, the current thickness increases due to a hydraulic jump. This phenomenon occurs under special inlet conditions and has a significant effect on the current structure including velocity profile, current height and bed shear stress. Flows with different inlet Froude numbers based on various inlet concentrations behave more distinctly than those based on different inlet opening heights. Laboratory experiments indicate that an increase in the inlet Froude number causes an increase... 

    Proposing a new model to approximate the elasticity modulus of granite rock samples based on laboratory tests results

    , Article Bulletin of Engineering Geology and the Environment ; Volume 78, Issue 3 , 2019 , Pages 1527-1536 ; 14359529 (ISSN) Behzadafshar, K ; Esfandi Sarafraz, M ; Hasanipanah, M ; Mojtahedi, S. F. F ; Tahir, M. M ; Sharif University of Technology
    Springer Verlag  2019
    An accurate examination of deformability of rock samples in response to any change in stresses is deeply dependent on the reliable determination of properties of the rock as analysis inputs. Although Young’s modulus (E) can provide valuable characteristics of the rock material deformation, the direct determination of E is considered a time-consuming and complicated analysis. The present study is aimed to introduce a new hybrid intelligent model to predict the E of granitic rock samples. Hence, a series of granitic block samples were collected from the face of a water transfer tunnel excavated in Malaysia and transferred to laboratory to conduct rock index tests for E prediction. Rock index... 

    Saturated hydraulic conductivity of problematic soils measured by a newly developed low-compliance triaxial permeameter

    , Article Engineering Geology ; Volume 278 , 2020 Sadeghi, H ; AliPanahi, P ; Sharif University of Technology
    Elsevier B.V  2020
    Research on the reliable characterization of saturated permeability has received great yet necessary attention globally. However, most studies were carried out on soils with a volumetric tendency being almost insensitive to water saturation or at least with this hidden assumption. This is clearly not the case when dealing with the two broad categories of problematic soils, including collapsible and expansive soils. As confirmed by previous research, at least one-fifth of the planet comprises of these soils with a relatively fair distribution. Therefore, the main objective of this study is to introduce a low-compliance double cell/burette permeameter to track all volumetric changes during the... 

    Hysteresis of soil water retention and shrinkage behaviour for various salt concentrations

    , Article Geotechnique Letters ; Volume 11, Issue 1 , 2021 , Pages 21-29 ; 20452543 (ISSN) Sadeghi, H ; Nasiri, H ; Sharif University of Technology
    ICE Publishing  2021
    Laboratory investigation on the influence of solute concentration on the soil water-retention curve (SWRC) and volumetric behaviour of expansive soils has received much attention in recent years due to increasing environmental pollution. However, most studies only considered applying wetting or drying path with almost no attention to hydraulic hysteresis. Furthermore, these studies have focused on examining expansive soils and only marginal effort has been devoted to collapsible soils. Therefore, the main objective of this study is to systematically explore the SWRC and shrinkage characteristics of an artificially made collapsible soil at various molar concentrations. The tests were... 

    Bench-scaled nano-Fe 0 permeable reactive barrier for nitrate removal

    , Article Ground Water Monitoring and Remediation ; Volume 31, Issue 4 , 2011 , Pages 82-94 ; 10693629 (ISSN) Hosseini, S. M ; Ataie Ashtiani, B ; Kholghi, M ; Sharif University of Technology
    There are many fundamental problems with the injection of nano-zero-valent iron (NZVI) particles to create permeable reactive barrier (PRB) treatment zone. Among them the loss of medium porosity or pore blocking over time can be considered which leads to reduction of permeability and bypass of the flow and contaminant plume up-gradient of the PRB. Present study provides a solution for such problems by confining the target zone for injection to the gate in a funnel-and-gate configuration. A laboratory-scale experimental setup is used in this work. In the designed PRB gate, no additional material from porous media exists. NZVI (d 50 = 52 ± 5 nm) particles are synthesized in water mixed with... 

    Anaerobic treatment of synthetic medium-strength wastewater using a multistage biofilm reactor

    , Article Bioresource Technology ; Volume 100, Issue 5 , 2009 , Pages 1740-1745 ; 09608524 (ISSN) Ghaniyari Benis, S ; Borja, R ; Monemian, S. A ; Goodarzi, V ; Sharif University of Technology
    A laboratory-scale multistage anaerobic biofilm reactor of three compartments with a working volume of 54-L was used for treating a synthetic medium-strength wastewater containing molasses as a carbon source at different influent conditions. The start-up period, stability and performance of this reactor were assessed at mesophilic temperature (35 °C). During the start-up period, pH fluctuations were observed because there was no microbial selection or zoning, but as the experiment progressed, results showed that phase separation had occurred inside the reactor. COD removal percentages of 91.6, 91.6, 90.0 and 88.3 were achieved at organic loading rates of 3.0, 4.5, 6.75 and 9.0 kg COD/m3 day,... 

    Effect of salinity and ion type on formation damage due to inorganic scale deposition and introducing optimum salinity

    , Article Journal of Petroleum Science and Engineering ; Volume 177 , 2019 , Pages 270-281 ; 09204105 (ISSN) Ghasemian, J ; Riahi, S ; Ayatollahi, S ; Mokhtari, R ; Sharif University of Technology
    Elsevier B.V  2019
    Smart water injection is recognized as an effective EOR process to alter the wettability and interfacial tension to obtain higher micro/macro sweep efficiencies. This water contains reactive ions such asMg2+, Ca2+ andSO42- which can act as potential-determining ions and change the surface charge of calcite rocks. One of the major concerns in the execution of an effective water-flood process, especially in tight carbonate reservoirs, is the chemical incompatibility between the formation brine and the injecting water. In the present study, laboratory fluid compatibility tests were carried out and software simulation was done to investigate the most important challenges of the water-flooding... 

    Development of bioreactors for comparative study of natural attenuation, biostimulation, and bioaugmentation of petroleum-hydrocarbon contaminated soil

    , Article Journal of Hazardous Materials ; Volume 342 , 2018 , Pages 270-278 ; 03043894 (ISSN) Safdari, M. S ; Kariminia, H. R ; Rahmati, M ; Fazlollahi, F ; Polasko, A ; Mahendra, S ; Wilding, W. V ; Fletcher, T. H ; Sharif University of Technology
    Elsevier B.V  2018
    Bioremediation of soil and groundwater sites contaminated by petroleum hydrocarbons is known as a technically viable, cost-effective, and environmentally sustainable technology. The purpose of this study is to investigate laboratory-scale bioremediation of petroleum-hydrocarbon contaminated soil through development of eight bioreactors, two bioreactors for each bioremediation mode. The modes were: (1) natural attenuation (NA); (2) biostimulation (BS) with oxygen and nutrients; (3) bioaugmentation (BA) with hydrocarbon degrading isolates; (4) a combination of biostimulation and bioaugmentation (BS-BA). Total petroleum hydrocarbons (TPH) mass balance over the bioreactors showed about 2% of...