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precipitation
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Increasing risk of meteorological drought in the Lake Urmia basin under climate change: Introducing the precipitation–temperature deciles index
, Article Journal of Hydrology ; 2020 ; Najafi, M. R ; Abrishamchi, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Meteorological droughts due to the concurrent occurrence of low-precipitation and high-temperature events can lead to severe negative impacts on agriculture, economy, ecosystem, and society. This study proposes a novel framework to characterize such drought conditions based on the joint variability of precipitation–temperature, particularly under climate change. Generalized hierarchical linear model is used to downscale precipitation and temperature at multiple stations from the outputs of nine General Circulation Models (GCMs) under Representative Concentration Pathways (RCPs) 4.5 and 8.5. A bivariate drought index called Precipitation–Temperature Deciles Index (PTDI) is developed using...
Plasma electrolytic oxidation and corrosion protection of friction stir welded AZ31B magnesium alloy-titanium joints
, Article Surface and Coatings Technology ; Volume 393 , 2020 ; Rogov, A ; Skeldon, P ; Zhou, X ; Yerokhin, A ; Aliabadi, A ; Ghorbani, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Joining of dissimilar light metals by friction stir welding (FSW) is of interest to reduce weight and fuel consumption in the transport sector. Such coupled metals may need protective surface treatments, e.g. against wear or corrosion, for some applications. In this work, the formation of plasma electrolytic oxidation (PEO) coatings in a silicate-based electrolyte for corrosion protection of FSW AZ31B magnesium alloy-titanium joints has been studied. The joints, if unprotected, may be susceptible to severe galvanic corrosion in chloride-containing environments. The coatings were characterized by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Mg2SiO4 and...
Preparation of mesoporous nanostructure NiO–MgO–SiO2 catalysts for syngas production via propane steam reforming
, Article International Journal of Hydrogen Energy ; Volume 45, Issue 11 , 2020 , Pages 6604-6620 ; Kazemeini, M ; Farhadi, F ; Rezaei, M ; Keshavarz, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this research, the propane steam reforming (PSR) as a promising alternative route over a mesoporous NiO–MgO–SiO2 catalyst to produce syngas (SG) was undertaken. This catalyst was prepared using a co-precipitation method followed by hydrothermal treatment. The influence of such catalyst preparation factors as the hydrothermal time and temperature, pH and calcination temperature on the physicochemical characteristics of the prepared samples were examined. Next, these materials were characterized through the BET-BJH, XRD, TPR, and FTIR analyses. The thermal stability of this catalyst was tested through the TGA and DTA techniques. Furthermore, the deactivation of the calcined catalysts at...
The impact of pavement permeability on time of concentration in a small urban watershed with a semi-arid climate
, Article Water Resources Management ; Volume 34, Issue 9 , 2020 , Pages 2969-2988 ; Tajrishy, M ; Jalilvand, E ; Sharif University of Technology
Springer
2020
Abstract
Despite the popularity of the permeable pavements in urban areas in recent years, a few empirical equations have been developed to estimate the time of concentration (Tc) on pervious surfaces, and almost none of them is evaluated over the permeable pavements. In this paper, we aim to investigate the effect of low impact development (LID) on Tc and develop a new equation for estimating overland flow Tc compatible with both permeable and impermeable pavements in small urban watersheds with a semi-arid climate. An experimental model was devised to determine the new equation. Synthetic rainfall (22–40 mm.h−1) was applied to a rectangular shaped (6 m × 1 m) test watershed with an adjustable...
Oxidation-precipitation of magnetic Fe3O4/AC nanocomposite as a heterogeneous catalyst for electro-Fenton treatment
, Article Chemical Engineering Communications ; Volume 207, Issue 5 , 2020 , Pages 665-675 ; Askari, N ; Rahman Setayesh, S ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
The oxidation-precipitation method was used for the synthesis of Fe3O4/AC. The characterization of the catalyst was accomplished by XRD, FT-IR, FE-SEM, BET, and VSM techniques. The obtained results indicated that magnetite nanoparticles were successfully prepared with cubic spinel structures and uniform distribution on the surface of activated carbon by the oxidation-precipitation method. The effect of operating parameters was evaluated to determine the optimum operating condition for the electro-Fenton (EF) removal of catechol as a phenolic pollutant model. At the optimum operating conditions (pH 3, Fe3O4/AC: 0.9 g L−1, Catechol: 8.0 × 10−4mol L−1 at I: 120 mA), the catechol and COD removal...
Flow stress of 2024 aluminum alloy during multi-directional forging process and natural aging after plastic deformation
, Article Materials Chemistry and Physics ; Volume 254 , 2020 ; Kazeminezhad, M ; Shadkam, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The hardening behavior of heat treatable alloys during deformation is attributed to three mechanisms of forest dislocations, solid solution and precipitation hardening which hinder the motion of dislocations and increase the density of statistically stored dislocation. In this paper, a model for the flow stress of a 2024 heat treatable aluminum alloy during plastic deformation is developed combining the superposition of these three hardening mechanisms. This model was then implemented into the finite element model in order to evaluate the evolution of the flow stress of 2024 aluminum alloy during multi-directional forging (MDF). Subsequently, an equation is developed for evaluating the...
The effect of seasonal variation in precipitation and evapotranspiration on the transient travel time distributions
, Article Advances in Water Resources ; Volume 142 , 2020 ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Precipitation (P), plant water use, and evaporation from the soil surface control the travel time of streamflow (Q) and evapotranspiration (ET) in a complex way. However, the impact of soil moisture and energy availability on the travel time distribution (TTD) of evaporated and transpired waters are yet less understood. In this study, we investigate how the seasonal variability of P and ET in terms of phase shift and rate influences the temporal dynamics of TTDs. To this end, we choose four contrasting climate types described as in-phase P and ET, out-of-phase P and ET, year-round constant P with seasonal ET, and year-round constant ET with seasonal P. We use a physically-based hydrological...
Immobilization of laccase from trametes hirsuta onto CMC coated magnetic nanoparticles
, Article International Journal of Engineering, Transactions A: Basics ; Volume 33, Issue 4 , 2020 , Pages 513-519 ; Ghazvini, S ; Hejazi, S ; Yaghmaei, S ; Ghobadi Nejad, Z ; Sharif University of Technology
Materials and Energy Research Center
2020
Abstract
In this study Fe3O4/CMC magnetic nanoparticles were synthesized through co-precipitation method. Afterward, laccase from Trametes hirsuta was immobilized onto Carboxymethyl cellulose (CMC)-coated magnetic Fe3O4 nanoparticles by covalent bonding between carboxyl groups of carboxymethyl cellulose and amine group of laccases. Also, the resulted magnetic nanoparticles and immobilized laccase were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and dynamic light scattering (DLS) analysis. Moreover, the vital factors in enzyme immobilization, such as contact time, amount of N-hydroxysuccinimide (NHS), and the amount of nanoparticles were...
Optimization of peroxidase-catalyzed oxidative coupling process for phenol removal from wastewater using response surface methodology
, Article Environmental Science and Technology ; Volume 41, Issue 20 , 2007 , Pages 7073-7079 ; 0013936X (ISSN) ; Torabi, S. F ; Ranaei Siadat, S. O ; Jalali Heravi, M ; Ghaemi, N ; Khajeh, K ; Sharif University of Technology
2007
Abstract
Hydroxylated aromatic compounds (HACs) are considered to be primary pollutants in a wide variety of industrial wastewaters. Horseradish peroxidase (HRP) is suitable for the removal of these toxic substances. However, development of a mathematical model and optimization of the HRP-based treatment considering the economical issues by novel methods is a necessity. In the present study, optimization of phenol removal from wastewater by horseradish peroxidase (HRP) was carried out using response surface methodology (RSM) and central composite design (CCD). As the initial experimental design, 2 4-1 half-fraction factorial design (H-FFD) is accomplished in triplicate at two levels to select the...
Apatite-coated Ag/AgBr/TiO2 visible-light photocatalyst for destruction of bacteria
, Article Journal of the American Chemical Society ; Volume 129, Issue 31 , 2007 , Pages 9552-9553 ; 00027863 (ISSN) ; Rahimnejad, S ; Haghighi, S ; Gholami, M. R ; Sharif University of Technology
2007
Abstract
Apatite-coated Ag/AgBr/TiO2 was prepared by deposition of Ag as novel metal to generate electron-hole pairs by extending the excitation wavelength to the visible-light region, AgBr, and hydroxy apatite as photosensitive material and adsorption bioceramic, respectively. The energy dispersive X-ray spectrometry clearly showed the presence of Ti, Ag, Ca, and P elements on the surface of catalyst. The bactericidal experiments in dark media indicated that only the novel catalyst shows inhibiting growth of bacteria in this case. A transmission electron microscopy image illustrated that catalyst nanoparticles adhere to the outer membrane of the cell and act as an inhibitor to the nourishment of...
Extraction and purification of phosphatidylcholine and its potential in nanoliposomal delivery of eucalyptus citriodora oil
, Article Canadian Journal of Chemical Engineering ; 2021 ; 00084034 (ISSN) ; Vaziri, A. S ; Alemzadeh, I ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Phosphatidylcholine (PC) possesses amphiphilic characteristics to form vesicles or liposome nanoparticles and can be utilized to deliver essential nutrients such as proteins, peptide antigens, and essential fatty acids. In this study, an attempt has been made to obtain purified PC and evaluate its potential in nanoliposome synthesis and its corresponding drug release profile. In this regard, four physical separation techniques comprising extraction, precipitation, static, and dynamic adsorption were assessed and applied to purify PC from soybean lecithin. Different solvents and the ratio of lecithin to solvent were used to achieve the highest PC percentage. The results of an HPLC test showed...
Microstructure evolution mechanism and corrosion behavior of transient liquid phase bonded 304l stainless steel
, Article Metals and Materials International ; Volume 27, Issue 9 , 2021 , Pages 3417-3431 ; 15989623 (ISSN) ; Binesh, B ; Sharif University of Technology
Korean Institute of Metals and Materials
2021
Abstract
Abstract: Transient liquid phase (TLP) bonding of 304L austenitic stainless steel was carried out using MBF-20 interlayer at 1070 °C with different holding times. The effect of bonding time on the microstructure and corrosion resistance of the TLP bonded samples was investigated aiming to obtain the optimal bonding time. The results showed that isothermal solidification was completed within 45 min at 1070 °C and shorter holding times gave rise to the formation of intermetallic compounds at the joint centerline. It was found that the solidification sequence in the joint region is as follows: (1) isothermal solidification of γ solid solution, (2) formation of ternary eutectic of γ + Ni boride...
Synthesis and optimization of CuxNi0.6-xMn0.4Fe2O4 oxygen carrier for chemical looping steam methane reforming
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2021 ; 15567036 (ISSN) ; Heydari Nasab, A ; Soltanieh, M ; Maddah, B ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
The self-supported CuxNi0.6-xMn0.4Fe2O4 oxygen carrier (x = 0.1–0.5) is synthesized to be applied in the chemical looping steam methane reforming (CL-SMR) process through the synthesized co-precipitation method. The response surface methodology (RSM) based on the Box–Behnken model is adopted to evaluate the effects of independent variables on the functionality of responses as well as predicting the best response volume. In this method, the variables consisting of reaction temperature (550–700°C), oxygen carrier (OC) loading percentage (0.1–0.5), steam-to-CH4 ratio (S/C), (1.5–3.5), and redox cycles’ count (10–24) and the responses consisting of hydrogen (H2) production yield, CH4 conversion...
Increasing risk of meteorological drought in the Lake Urmia basin under climate change: Introducing the precipitation–temperature deciles index
, Article Journal of Hydrology ; Volume 592 , 2021 ; 00221694 (ISSN) ; Najafi, M. R ; Abrishamchi, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Meteorological droughts due to the concurrent occurrence of low-precipitation and high-temperature events can lead to severe negative impacts on agriculture, economy, ecosystem, and society. This study proposes a novel framework to characterize such drought conditions based on the joint variability of precipitation–temperature, particularly under climate change. Generalized hierarchical linear model is used to downscale precipitation and temperature at multiple stations from the outputs of nine General Circulation Models (GCMs) under Representative Concentration Pathways (RCPs) 4.5 and 8.5. A bivariate drought index called Precipitation–Temperature Deciles Index (PTDI) is developed using...
Increasing risk of meteorological drought in the Lake Urmia basin under climate change: Introducing the precipitation–temperature deciles index
, Article Journal of Hydrology ; Volume 592 , 2021 ; 00221694 (ISSN) ; Najafi, M. R ; Abrishamchi, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Meteorological droughts due to the concurrent occurrence of low-precipitation and high-temperature events can lead to severe negative impacts on agriculture, economy, ecosystem, and society. This study proposes a novel framework to characterize such drought conditions based on the joint variability of precipitation–temperature, particularly under climate change. Generalized hierarchical linear model is used to downscale precipitation and temperature at multiple stations from the outputs of nine General Circulation Models (GCMs) under Representative Concentration Pathways (RCPs) 4.5 and 8.5. A bivariate drought index called Precipitation–Temperature Deciles Index (PTDI) is developed using...
In-depth characterization of light, medium and heavy oil asphaltenes as well as asphaltenes subfractions
, Article Fuel ; Volume 324 , 2022 ; 00162361 (ISSN) ; Husein, M. M ; Ghotbi, C ; Dabir, B ; Taghikhani, V ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Asphaltenes, and their related issues, have been the focus of many literature investigations. However, in-depth analysis of asphaltenes structure and its relation to asphaltenes stability has been considered by fewer studies. In this research, extensive analysis of the structure of asphaltenes extracted from light, medium, and heavy oils is provided, together with analysis of three subfractions of the medium oil asphaltene having the least, intermediate, and highest solubilities. To this end, elemental analysis, EDX, mass spectroscopy, FTIR, NMR, XRD, and SEM results were collected. Higher hydrogen content and hydrogen/carbon atomic ratio, lower aromatic nature and olefinic entities were...
Efficient post-plasma catalytic degradation of toluene via series of Co–Cu/TiO2 catalysts
, Article Research on Chemical Intermediates ; Volume 48, Issue 10 , 2022 , Pages 4227-4248 ; 09226168 (ISSN) ; Zaman, W. Q ; Miran, W ; Ali, M ; Abbas, Z ; Mushtaq, U ; Shahzad, A ; Yang, J ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
Volatile organic compounds (VOCs) represent a very important class of pollutants that causes serious health effects. There is an urgent requirement to establish efficient technologies that can reduce and control VOCs. Non-thermal plasma (NTP) is an emerging technology that can decompose low concentration VOCs. However, the low efficiency and high power cost are major hindrances in its commercialization. In this work, Co–Cu with TiO2 support catalysts are prepared by using the deposition precipitation method and utilized in post-plasma catalysis for the efficient degradation of toluene selected as a model VOC. The synergistic effect of Co–Cu/TiO2 with different Co/Cu molar ratios along with...
Extraction and purification of phosphatidylcholine and its potential in nanoliposomal delivery of Eucalyptus citriodora oil
, Article Canadian Journal of Chemical Engineering ; Volume 100, Issue 10 , 2022 , Pages 2807-2814 ; 00084034 (ISSN) ; Vaziri, A. S ; Alemzadeh, I ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
Phosphatidylcholine (PC) possesses amphiphilic characteristics to form vesicles or liposome nanoparticles and can be utilized to deliver essential nutrients such as proteins, peptide antigens, and essential fatty acids. In this study, an attempt has been made to obtain purified PC and evaluate its potential in nanoliposome synthesis and its corresponding drug release profile. In this regard, four physical separation techniques comprising extraction, precipitation, static, and dynamic adsorption were assessed and applied to purify PC from soybean lecithin. Different solvents and the ratio of lecithin to solvent were used to achieve the highest PC percentage. The results of an HPLC test showed...
A probabilistic climate change assessment for Europe
, Article International Journal of Climatology ; Volume 42, Issue 13 , 2022 , Pages 6699-6715 ; 08998418 (ISSN) ; Teuling, A. J ; Uijlenhoet, R ; Sharif University of Technology
John Wiley and Sons Ltd
2022
Abstract
Globally, the impacts of climate change can vary across different regions. This study uses a probability framework to evaluate recent historical (1976–2016) and near-future projected (until 2049) climate change across Europe using Climate Research Unit and ensemble climate model datasets (under RCPs 2.6 and 8.5). A historical assessment shows that although the east and west of the domain experienced the largest and smallest increase in temperature, changes in precipitation are not as smooth as temperature. Results indicate that the maximum changes between distributions of the variables (temperature and precipitation) mainly occur at extreme percentiles (e.g., 10% and 90%). A group analysis...
Laser welding of titanium grade 2 and aluminium AA 3105-O using a new AlScZr filler metal
, Article Lasers in Manufacturing and Materials Processing ; Volume 9, Issue 1 , 2022 , Pages 37-55 ; 21967229 (ISSN) ; Sadrnezhaad, S. K ; Alali, M ; Fakouri Hasanabadi, M ; Torkamany, M. J ; Abass, M. H ; Mahmoud, A. K ; Kokabi, A. H ; Sharif University of Technology
Springer
2022
Abstract
In this study, a pulsed Nd:YAG laser welding method is implemented to join Ti-G2 (1 mm thick) to AA3105-O (0.5 mm thick) via a ring of spots filled with AlScZr alloy (0.15 mm thick). The filler material improved the weld’s microstructure and mechanical properties by reducing the undesirable intermetallic compounds (IMCs) such as TiAl2 and TiAl3 in the aluminium re-solidified zone near the titanium/aluminium interface. The joints having AlScZr filler were mostly failed at Al heat affected zone (HAZ) during the tensile shear test. The addition of zirconium to binary Al–Sc system formed a substitutional solid-solution in which 50 wt% Zr+10 wt% Ti replaced Al3(Sc,Zr,Ti). Scandium had a...