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Multi-objective optimal design of gas-fired heater based on modified design model of fired heater taking into account exergy, economic and environmental factors
, Article International Journal of Engineering, Transactions A: Basics ; Volume 34, Issue 7 , 2021 , Pages 1785-1798 ; 17281431 (ISSN) ; Rezaei, F ; Saboohi, Y ; Sassani, F ; Sharif University of Technology
Materials and Energy Research Center
2021
Abstract
Heaters are one of the central parts of natural gas reduction stations using turboexpanders to prevent the formation of hydrate and corrosion failure. This study intends to design a fired heater by applying a combustion sub-model to derive an optimal model for this kind of application. This model is developed to accurately consider all subsections of the fired heater namely radiation, convection, and shield sections, as well as flue gas composition, and its volume. Within this context, a multi-objective optimization is employed to identify the optimal design of the gas-fired heater in the natural gas reduction station for the Ramin power plant case study. The total economic and environmental...
Mechanical characteristics of cement paste in the presence of carbon nanotubes and silica oxide nanoparticles: An experimental study
, Article Materials ; Volume 14, Issue 6 , 2021 ; 19961944 (ISSN) ; Farhangi, V ; Farani, M. R ; Joshaghani, A ; Zadehmohamad, M ; Ahmadzadeh, M ; Sharif University of Technology
MDPI AG
2021
Abstract
Considering the remarkable characteristics of nanomaterials, previous research studies investigated the effects of incorporating different types of these materials on improving the concrete properties. However, further studies are required to evaluate the complementary hybridization and synergistic influence of nanomaterials. In this research, the combined effect of adding nano silica particles (NS) and multi-walled carbon nanotubes (MWCNT) on enhancing both the compressive and flexural strengths of the cement paste was investigated. Moreover, the morphology of the interface between cement paste and aggregates was studied by scanning electron microscopy (SEM). The mixtures were prepared...
Effect of a monomeric sequence on the structure of hydrated Nafion in the sandwich model and solvent dynamics in nano-channels: A molecular dynamic study
, Article Molecular Physics ; Volume 108, Issue 24 , 2010 , Pages 3393-3404 ; 00268976 (ISSN) ; Akbarzadeh, H ; Taherkhani, F ; Parsafar, G ; Sharif University of Technology
2010
Abstract
Molecular dynamics simulations are performed to obtain insight into the structural properties of hydrated Nafion using the sandwich model of the polymer membrane. It is shown that a larger distance between the sulfonate groups of a chain leads to the polymer forming a better inverted micelles structure. Water- and hydronium-polymer interfaces are investigated. Comparing our results with others indicates that, from the perspective of distance, the formation of shells of water and hydronium ions is independent of the model and monomer type, but depends on both if the coordination number is considered. The behaviour of water molecules and hydronium ions is also studied dynamically. Our survey...
Thermodynamics and Kinetics Study of Gas Hydrates in Presence of Ionic Liquids
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Taghikhani, Vahid (Supervisor) ; Nazari, Khodadad (Supervisor)
Abstract
Gas hydrates are ice-like clathrate compounds. Methane, carbon dioxie and natural gas compounds can form gas hydrate and plug pipelines, in order to preventing of gas hydrate formation, inhibitors like electrolytes are added to the natural gas pipelines. In this work a model proposed to predict the hydrate formation conditions in presence of some inhibitors such as NaCl, KCl, NaBr, KBr, [BMIM][BF4] and [BMIM][Br]. So a new equation of state that can be applied to both electrolyte and associating solutions called GV-SAFT-MSA is developed. Two dialkylimidazolium ionic liquids [BMIM][BF4] and [BMIM][MS] have been investigated for their potential application as novel gas hydrate inhibitors. The...
Performance Modeling of Nano-Porous Monolayers in Water Desalination Using Molecular Dynamics Simulations Approach
, Ph.D. Dissertation Sharif University of Technology ; Moosavi, Ali (Supervisor) ; Nejat, Hossein (Co-Supervisor)
Abstract
Water plays an essential role in the daily lives of humans, plants, and animals. Due to the lack of safe water on the planet, in recent years there have been many challenges in the field of water treatment, which has made water desalination technology always one of the most advanced technologies. The most advanced technology in this field is the use of nanotechnology in water and wastewater treatment, especially the use of Membrane processes such as reverse osmosis. Unlike conventional reverse osmosis membranes, nanoporous membranes can ensure rapid water transfer during the displacement process. The purpose of this thesis is to introduce new monolayers that have an incredible performance in...
The agglomeration kinetics of aluminum hydroxide in Bayer process
, Article Powder Technology ; Volume 224 , July , 2012 , Pages 351-355 ; 00325910 (ISSN) ; Nattaghi, E ; Movahedirad, S ; Ranjbarian, S ; Farhadi, F ; Sharif University of Technology
2012
Abstract
The effects of temperature, seed mass and agitation rate on agglomeration kinetics of aluminum hydroxide in Bayer process have been studied in a batch system. Collected raw data were analyzed and the kinetics data of agglomeration were derived through simulation of the process using a pre-developed software. The results showed that agglomeration kinetics constant (agglomeration kernel) increases with increase in temperature and agitation rate. Moreover a maximum value of agglomeration rate versus added seed mass was observed. Furthermore the magnitude of calculated activation energy of agglomeration was close to that of growth
Mechanism of nanostructured fluorapatite formation from CaO, CaF2 and P2O5 precursors by mechanochemical synthesis
, Article Progress in Reaction Kinetics and Mechanism ; Volume 43, Issue 3-4 , 2018 , Pages 201-210 ; 14686783 (ISSN) ; Sadrnezhaad, S. K ; Vahdati Khaki, J ; Sharif University of Technology
Science Reviews 2000 Ltd
2018
Abstract
We determined the mechanism of mechanochemical synthesis of fluorapatite from CaO, CaF2 and P2O5 by characterisation of the intermediate compounds. We used atomic absorption spectroscopy, X-ray diffraction, field emission scanning electron microscopy, FTIR spectroscopy and transmission electron microscopy to find the transitional compounds. Investigation of the binary and ternary powder mixtures revealed the appearance of H3PO4, Ca(OH)2, Ca2P2O7 and CaCO3 as the intermediate compounds. At early stages of the milling, conversions of P2O5 to H3PO4 and CaO to Ca(OH)2 occurred in the wet atmosphere. Later, a combination of Ca(OH)2 and H3PO4 formed Ca2P2O7 while the unreacted CaO was converted to...
Application of the MSA-based models in correlating the surface tension for single and mixed electrolyte solutions
, Article Journal of Chemical Thermodynamics ; Volume 41, Issue 11 , 2009 , Pages 1264-1271 ; 00219614 (ISSN) ; Taghikhani, V ; Ghotbi, C ; Sharif University of Technology
2009
Abstract
Experimental values for surface tension of single and mixed electrolyte solutions were correlated using the models based on the perturbation theory. The Mean Spherical Approximation (MSA) model, coupled with the Ghotbi-Vera (GV) and the Mansoori et al. (BMCSL) equations of state, were used to correlate the experimental values of the surface tension. The results showed that the models can favourably correlate the experimental values for single electrolyte solutions. However, it was observed that the GV-MSA model can more accurately predict the surface tension for single electrolytes, especially at higher concentrations. Two different expressions for concentration dependency of cation hydrated...
Performance evaluation of slurry seals containing reclaimed asphalt pavement
, Article Transportation Research Record ; Volume 2673, Issue 1 , 2019 , Pages 358-368 ; 03611981 (ISSN) ; 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...
Graphene oxide nanoplatforms reduction by green plant-sourced organic compounds for construction of an active anti-corrosion coating; experimental/electronic-scale DFT-D modeling studies
, Article Chemical Engineering Journal ; Volume 397 , 1 October , 2020 ; Ramezanzadeh, M ; Akbarzadeh, S ; Bahlakeh, G ; Ramezanzadeh, B ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In this study, the Peganum harmala seed extract (PHSE) was used as a green reducing agent of graphene oxide with high deoxygenation capability. PHSE not only acts as a reducing agent of GO due to the high amount of nitrogen-rich compounds but also plays an essential role in the particles' active anti-corrosion performance improvement. In order to add more active inhibition property, the zinc cations were doped successfully on the chemical structure of GO nanosheets, and eventually, the RGO-PHSE-Zn nanocomposite was obtained. The FT-IR results and UV–visible achievements declared that the epoxide (-C-O-C-) functional groups attached to the surface of the GO nanosheets had been successfully...
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) ; 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...
An investigation on the influence of milling time and calcination temperature on the characterization of nano cerium oxide powder synthesized by mechanochemical route
, Article Materials Research Bulletin ; Volume 47, Issue 11 , 2012 , Pages 3586-3591 ; 00255408 (ISSN) ; Amoozegar, Z ; Sadrnezhaad, S. K ; Sharif University of Technology
2012
Abstract
The synthesis of nano-sized CeO 2 powder was investigated via mechanochemical reactions between hydrate cerium chloride and sodium hydroxide as the starting materials. The process was followed by a subsequent calcination procedure. Characterization of as-synthesized powder was performed using X-ray diffraction, FTIR spectroscopy, Brunner-Emmett-Teller (BET) nitrogen gas absorption, scanning electron microscopy (SEM) and particle size analyzer (PSA). The precursors were milled for different milling times and then were subjected to different heat treatment procedure at variable temperatures from 100 to 700 °C. According to the results, milling time and calcination temperatures induce...
Wettability alteration in carbonates during "Smart Waterflood": Underling mechanisms and the effect of individual ions
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 487 , 2015 , Pages 142-153 ; 09277757 (ISSN) ; Mousapour, M. S ; Ayatollahi, S ; Vossoughi, M ; Beigy, A. H ; Sharif University of Technology
Elsevier
2015
Abstract
There are increasing evidences that adjusting the chemistry of the injecting water improves the oil recovery efficiency. However, the underlying mechanisms for this technique which is referred to as "smart waterflood" have not yet been thoroughly understood. It is needed to explore the role of individual ions through set of different tests, to find the right mechanisms behind "smart waterflood". This study is focused on the fluid/solid (carbonate) interactions through systematic wettability measurement. Contact angle measurements accompanied by spontaneous imbibition tests were employed to determine the role of individual monovalent and divalent ions in wettability alteration process by...
Thermo-mechanical analysis of Roller Compacted Concrete (RCC) dams (Jahgin Dam)
, Article Proceedings of the Symposium on the Application of Geophyics to Engineering and Environmental Problems, SAGEEP, 29 March 2009 through 2 April 2009, Fort Worth, TX ; Volume 1 , 2009 , Pages 417-427 ; 15548015 (ISSN) ; 9781615670512 (ISBN) ; Ghaemian, M ; Azimfar, S. M ; Sharif University of Technology
Abstract
In this paper a procedure for two-dimensional unsteady thermo-mechanical analysis of layered structures is presented, allowing the determination of the temperature and stress field at each step the construction period. The finite element method is employed in the methodology. Numerical simulation are focused on concrete structures, particularly roller compacted concrete (RCC) dams. A time varying elasticity modulus is introduced in the model. One case study is presented and analysis under different design approaches. Thermal effects must be considered in the process of designing of certain types of concrete structures in order to prevent the damage during either the construction phase (early...
The impact of salinity on ionic characteristics of thin brine film wetting carbonate minerals: An atomistic insight
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 571 , 2019 , Pages 27-35 ; 09277757 (ISSN) ; Badizad, M. H ; Kargozarfard, Z ; Ayatollahi, S ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Connate water has been coexisting with oil and mineral for centuries within underground reservoirs. The oil recovery techniques, such as low salinity water injection, disturb this prolonged equilibrium state of oil/brine/rock system. However, a thorough understanding of this complex equilibrium in the reservoir is still lacking. In this study, we performed molecular dynamics simulations to provide quantitative comprehension of the thin brine film characteristics that wets carbonate reservoir rocks at molecular level. While an electric double layer is formed at the interface of calcite/low salinity water, the ions in the high saline water form several aggregates of ions. We found that these...
In vitro study of hydroxyapatite/polycaprolactone (HA/PCL) nanocomposite synthesized by an in situ sol-gel process
, Article Materials Science and Engineering C ; Volume 33, Issue 1 , 2013 , Pages 390-396 ; 09284931 (ISSN) ; Mohammadi, M. R ; Sharif University of Technology
2013
Abstract
Hydroxyapatite (HA) is the most substantial mineral constituent of a bone which has been extensively used in medicine as implantable materials, owing to its good biocompatibility, bioactivity high osteoconductive, and/or osteoinductive properties. Nevertheless, its mechanical property is not utmost appropriate for a bone substitution. Therefore, a composite consist of HA and a biodegradable polymer is usually prepared to generate an apt bone scaffold. In the present work polycaprolactone (PCL), a newly remarkable biocompatible and biodegradable polymer, was employed as a matrix and hydroxyapatite nanoparticles were used as a reinforcement element of the composite. HA/PCL nanocomposites were...
Hydrothermal synthesis of ZnO nanorod arrays for photocatalytic inactivation of bacteria
, Article Journal of Physics D: Applied Physics ; Volume 42, Issue 22 , 2009 ; 00223727 (ISSN) ; Mehrabian, M ; Mirabbaszadeh, K ; Azimirad, R ; Sharif University of Technology
2009
Abstract
Arrays of ZnO nanorods were synthesized on ZnO seed layer/glass substrates by a hydrothermal method at a low temperature of 70 °C. The effect of pH > 7 of the hydrated zinc nitrate-NaOH precursor on the morphology and topography (e.g. size, surface area and roughness), the optical characteristics (e.g. optical transmission and band-gap energy), hydrophilicity and antibacterial activity of the grown ZnO nanostructure and nanorod coatings were investigated. For pH = 11.33 of the precursor (NaOH concentration of 0.10M), a fast growth of ZnO nanorods on the seed layer (length of ∼1 νm in 1.5 h) was observed. The fast growth of the ZnO nanorods resulted in a significant reduction in the optical...
3D Bioprinting of oxygenated cell-laden gelatin methacryloyl constructs
, Article Advanced Healthcare Materials ; Volume 9, Issue 15 , 2020 ; Darabi, M. A ; Nasiri, R ; Sangabathuni, S ; Ertas, Y. N ; Alem, H ; Hosseini, V ; Shamloo, A ; Nasr, A. S ; Ahadian, S ; Dokmeci, M. R ; Khademhosseini, A ; Ashammakhi, N ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
Cell survival during the early stages of transplantation and before new blood vessels formation is a major challenge in translational applications of 3D bioprinted tissues. Supplementing oxygen (O2) to transplanted cells via an O2 generating source such as calcium peroxide (CPO) is an attractive approach to ensure cell viability. Calcium peroxide also produces calcium hydroxide that reduces the viscosity of bioinks, which is a limiting factor for bioprinting. Therefore, adapting this solution into 3D bioprinting is of significant importance. In this study, a gelatin methacryloyl (GelMA) bioink that is optimized in terms of pH and viscosity is developed. The improved rheological properties...
Niosomal formulation for antibacterial applications
, Article Journal of Drug Targeting ; Volume 30, Issue 5 , 2022 , Pages 476-493 ; 1061186X (ISSN) ; Gharehchelou, B ; Haghighi Poodeh, S ; Jamshidifar, E ; Karimifard, S ; Farasati Far, B ; Akbarzadeh, I ; Seifalian, A ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Infection is a disease that is mainly caused by different Gram-negative and Gram-positive bacteria. Treatment of infections requires a considerable amount of antibiotics, which can cause serious damage to the patient's body. Delivering the antibiotic only to the site of infection can prevent these destructive effects, such as the destruction of the normal intestinal flora. The drug delivery system through carriers will take antibiotics into a part of the body involved in the disease. Niosome nanoparticles, which have been made from non-ionic surfactants, have been emerging as ideal drug/antibiotics delivery vehicles. Recently, niosome formulations have been targeted to reduce toxicity and...
Delivery of melittin-loaded niosomes for breast cancer treatment: an in vitro and in vivo evaluation of anti-cancer effect
, Article Cancer Nanotechnology ; Volume 12, Issue 1 , 2021 ; 18686958 (ISSN) ; Akbarzadeh, I ; Marzbankia, E ; Farid, M ; khaledi, L ; Reihani, A. H ; Javidfar, M ; Mortazavi, P ; Sharif University of Technology
BioMed Central Ltd
2021
Abstract
Background: Melittin, a peptide component of honey bee venom, is an appealing candidate for cancer therapy. In the current study, melittin, melittin-loaded niosome, and empty niosome had been optimized and the anticancer effect assessed in vitro on 4T1 and SKBR3 breast cell lines and in vivo on BALB/C inbred mice. "Thin-layer hydration method" was used for preparing the niosomes; different niosomal formulations of melittin were prepared and characterized in terms of morphology, size, polydispersity index, encapsulation efficiency, release kinetics, and stability. A niosome was formulated and loaded with melittin as a promising drug carrier system for chemotherapy of the breast cancer cells....