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Structure of human errors in tasks of operators working in the control room of an oil refinery unit
, Article Indian Journal of Science and Technology ; Volume 5, Issue 2 , Feb , 2012 , Pages 2065-2070 ; 09746846 (ISSN) ; Jafari, M. J ; Ghalehnoi, M ; Mehrabi, Y ; Ghadiri, M ; Nikbakht, M ; Sharif University of Technology
2012
Abstract
In the present research, human errors existed in tasks of operators working in two control rooms (Northern and Southern control rooms) in the Tehran oil refinery are identified and evaluated. Then, corrective strategies and actions are advised to decrease errors. At first, using hierarchical task analysis (HTA) method, four positions including shift controller, head operators, control room's operators, and outside operators are analyzed. Afterwards, human errors in the considered positions are identified and assessed using technique for retrospective and predictive analysis of cognitive errors (TRACEr). Results present 670 internal errors and 738 external errors in the Northern sector while...
Study on Continuous Phase Holdup in a Pulsed Disc and Doughnut Extraction Column by Radiotracer Technique
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Tabasi, Mohsen (Supervisor) ; Mostaedi, M.T (Co-Advisor)
Abstract
The dispersed phase holdup is one of the important parameters in the design pulsed column and set the column diameter, height and characteristics of flooding and mass transfer. High efficiency and low space requirements of these columns cause is particularly in the nuclear industry, Due to the possible presence of radiation and the need for protection against radiation, considered and used. In this project, the dispersed phase holdup and mean residence time in a pulsed disc and donut column in a semi-industrial scale using radiotracer and shut down methods compared and presented for water-kerosene system. Also axial dispersion coefficient in the column using radiotracer methods is calculated...
Measurement of Radionuclides Transport Parameters for Soil Samples from Anarak Radioactive Waste Disposal Site by Collimated Gamma Ray Spectroscopy
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor)
Abstract
The Iranian Nuclear waste management Company is responsible for the safe disposal of the low-level radioactive waste resulting from the various processes of the nuclear fuel cycle and other radioactive-related activities. The safety assessment of waste disposal requires the measurement of transport parameters of radioactive nuclides in the soil around the disposal site.In this project, concentration profiles within a column which filled with Anarak Radioactive Waste Disposal Site soil were obtained using collimated gamma scanning method. Concentration profiles were measured at two different times (69 and 138 hours after injection). Then, using STANDMOD software, the equilibrium...
Effect of Natural Ligands on Transport of Radionuclides in Soil Column of Naeen Repository
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor)
Abstract
Nuclear waste management in Iran is the responsibility of the Nuclear Waste Company. The waste company is obliged to bury waste with a certain level of radioactivity, resulting from various processes of the nuclear fuel cycle or other processes such as research projects and medical centers, after the necessary measures, finally at the Anarak landfill site. To evaluate the safety of the site, it is necessary to study the parameters of radioactive nucleation in the soil. Humic substances from natural substances in the soil affect the transport of radioactive nuclei. In this project, to study the effects of the presence of humic acid, the soil of Anarak residue in three weight percent...
Tracer transport in naturally fractured reservoirs: Analytical solutions for a system of parallel fractures
, Article International Journal of Heat and Mass Transfer ; Volume 103 , 2016 , Pages 627-634 ; 00179310 (ISSN) ; Hossieni, M ; Izadmehr, M ; Sharifi, M ; Sharif University of Technology
Elsevier Ltd
Abstract
In naturally fractured reservoirs, modeling of mass transfer between matrix blocks and fractures is an important subject during gas injection or contaminant transport. This study focuses on developing an exact analytical solution to transient tracer transport problem along a discrete fracture in a porous rock matrix. Using Gauss-Legendre quadrature, an expression was obtained in the form of a double integral which is considered as the general transient solution. This solution has the ability to account the following phenomena: advective transport in fractures and molecular diffusion from the fracture to the matrix block. Certain assumptions are made which allow the problem to be formulated...
A new method for determination of concentration profile in a transport column by gamma spectroscopy combined with genetic algorithm
, Article Progress in Nuclear Energy ; Volume 124 , 2020 ; Kazemi, Z ; Samadfam, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
A non-collimated gamma spectroscopy with fewer sampling (counting) and shorter sampling periods is developed and used to estimate the concentration profile of the radiotracers within the column. In this method, the radiotracer activity in the whole column is measured in a few different positions of the detector and then, by using an appropriate advection-dispersion model and the genetic algorithm, the concentration profile within the column is constructed. The concentration profile obtained by the new method fits very well to the experimentally obtained thin-section scanning results with RMSE less than 0.046. The uniqueness of the concentration profile obtained by the method was confirmed by...
Review of Baseflow Estimation Methods and Sensitivity Analysis to the Incorporate Parameters Application of Anzali Wetland Watershed
, M.Sc. Thesis Sharif University of Technology ; Ataie Ashtiani, Behzad (Supervisor)
Abstract
Quantitative estimation of baseflow is necessary for hydrological modeling of a watershed, ground-surface water interaction, water supply reliability, and vulnerability, especially during a dry period, and answering questions pertaining to the responses of human-based activities on natural ecosystems. Extensive research effort spanning more than 50 years provided collections of field, manual, and computer-based methods for baseflow separation study. In this study, a comprehensive review is carried out on the nine digital filters, six graphical methods, four tracer-mass-balance methods, fourteen recession analysis methods, and two frequency analysis methods. Sensitivity analyses of baseflow...
Tuning the dispersion of reactive solute by steady and oscillatory electroosmotic-Poiseuille flows in polyelectrolyte-grafted micro/nanotubes
, Article Journal of Fluid Mechanics ; 2019 , Pages 73-112 ; 00221120 (ISSN) ; Saidi, M. H ; Sharif University of Technology
Cambridge University Press
2019
Abstract
This paper extends the analysis of solute dispersion in electrohydrodynamic flows to the case of band broadening in polyelectrolyte-grafted (soft) capillaries by accounting for the effects of ion partitioning, irreversible catalytic reaction and pulsatile flow actuation. In the Debye-Hückel limit, we present the benchmark solutions of electric potential and velocity distribution pertinent to steady and oscillatory mixed electroosmotic-pressure-driven flows in soft capillaries. Afterwards, the mathematical models of band broadening based on the Taylor-Aris theory and generalized dispersion method are presented to investigate the late-time asymptotic state and all-time evolution of...
Tuning the dispersion of reactive solute by steady and oscillatory electroosmotic-Poiseuille flows in polyelectrolyte-grafted micro/nanotubes
, Article Journal of Fluid Mechanics ; 2019 , Pages 73-112 ; 00221120 (ISSN) ; Saidi, M. H ; Sharif University of Technology
Cambridge University Press
2019
Abstract
This paper extends the analysis of solute dispersion in electrohydrodynamic flows to the case of band broadening in polyelectrolyte-grafted (soft) capillaries by accounting for the effects of ion partitioning, irreversible catalytic reaction and pulsatile flow actuation. In the Debye-Hückel limit, we present the benchmark solutions of electric potential and velocity distribution pertinent to steady and oscillatory mixed electroosmotic-pressure-driven flows in soft capillaries. Afterwards, the mathematical models of band broadening based on the Taylor-Aris theory and generalized dispersion method are presented to investigate the late-time asymptotic state and all-time evolution of...
Fluid particle diffusion through high-hematocrit blood flow within a capillary tube
, Article Journal of Biomechanics ; Volume 44, Issue 1 , Jan , 2011 , Pages 170-175 ; 00219290 (ISSN) ; Ishikawa, T ; Matsuki, N ; Jafar Abdekhodaie, M ; Imai, Y ; Ueno, H ; Yamaguchi, T ; Sharif University of Technology
2011
Abstract
Fluid particle diffusion through blood flow within a capillary tube is an important phenomenon to understand, especially for studies in mass transport in the microcirculation as well as in solving technical issues involved in mixing in biomedical microdevices. In this paper, the spreading of tracer particles through up to 20% hematocrit blood, flowing in a capillary tube, was studied using a confocal micro-PTV system. We tracked hundreds of particles in high-hematocrit blood and measured the radial dispersion coefficient. Results yielded significant enhancement of the particle diffusion, due to a micron-scale flow-field generated by red blood cell motions. By increasing the flow rate, the...
Association of biomarkers of systemic inflammation with organic components and source tracers in quasi-ultrafine particles
, Article Environmental Health Perspectives ; Volume 118, Issue 6 , 2010 , Pages 756-762 ; 00916765 (ISSN) ; Staimer, N ; Tjoa, T ; Arhami, M ; Polidori, A ; Gillen, D. L ; Kleinman, M. T ; Schauer, J. J ; Sioutas, C ; Sharif University of Technology
2010
Abstract
Background: Evidence is needed regarding the air pollutant components and their sources responsible for associations between particle mass concentrations and human cardiovascular outcomes. We previously found associations between circulating biomarkers of inflammation and mass concentrations of quasi-ultrafine particles ≤ 0.25 μm in aerodynamic diameter (PM0.25) in a panel cohort study of 60 elderly subjects with coronary artery disease living in the Los Angeles Basin.Objectives: We reassessed biomarker associations with PM0.25 using new particle composition data.Methods: Weekly biomarkers of inflammation were plasma interleukin-6 (IL-6) and soluble tumor necrosis factor-α receptor II...