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Preparation of α-MnO2 nanowires and its application in low temperature CO oxidation
Mehran Rezaei,Mohammad Sadeghinia,Ehsan Amini 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.11
α-MnO2 nanowires were synthesized through a simple hydrothermal route and employed as support to obtain CuO/α-MnO2 catalysts in low temperature CO oxidation. The prepared samples were characterized by X-ray diffraction (XRD), N2 adsorption (BET), temperature programmed reduction (TPR), thermal gravimetric/differential thermal analysis (TGA/DTA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The results showed that the prepared samples have nanowire morphology with a size about 30-40 nm in diameter. The obtained results revealed a remarkably high activity for the prepared catalysts in low temperature CO oxidation.
Rezaei Mehran,Talebi Ali Asghar,Fathipour Yaghoub,Karimzadeh Javad,Mehrabadi Mohammad 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1
This study was performed to investigate the age-dependent functional response of Aphidius matricariae Haliday (Hymenoptera: Braconidae) at varying densities of tobacco aphid, Myzus persicae nicotianae Blackman (Hemi ptera: Aphididae). Six densities (2, 4, 8, 16, 32, and 64 numbers) of third instar nymphs of M. persicae nicotianae were daily exposed to one pair of 1-day-old A. matricariae until the parasitoid female died. Each host aphid density was replicated 10 times. The experiments were conducted at constant environmental conditions (25 ± 1 ◦ C, 70 ± 5% RH and 16:8h L:D photoperiod). The logistic regression model demonstrated that the functional response of A. matricariae was type III in the second day and type II in the first day and from third to the end of adult parasitoid lifetime. The handling time (T h ) was lowest in the first day (0.2305 h) and highest in the sixth day (2.9296 h) of the parasitoid’s life. The searching efficiency (a) values were 0.0573, 0.0649, 0.0503, 0.0229, and 0.0077 h − 1 in the first, third, fourth, fifth, and sixth days of the parasitoid’s life, respectively. Also, the b value for type III functional response was 0.0147 in the second day. The values of maximum attack rate (T/T h ) ranged from 104.12 nymphs/24 h in the first day to 19.8 nymphs/24 h in the sixth day of parasitoid’s life. Based on the results, A. matricariae showed a high potential to control the population of tobacco aphid and the highest efficiency gained in the first half of the female parasitoid life.
Mehran Rezaei,Nima Bayat,Fereshteh Meshkani 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.2
Nickel catalysts supported on mesoporous nanocrystalline gamma alumina with various nickel loadings were prepared and employed for thermocatalytic decomposition of methane into COx-free hydrogen and carbon nanofibers. The prepared catalysts with different nickel contents exhibited mesoporous structure with high surface area in the range of 121.3 to 66.2m2g−1. Increasing in nickel content decreased the pore volume and increased the crystallite size. The catalytic results revealed that the nickel content and operating temperature both play important roles on the catalytic performance of the prepared catalysts. The results showed that increasing in reaction temperature increased the initial conversion of catalysts and significantly decreased the catalyst lifetime. Scanning electron microscopy (SEM) analysis of the spent catalysts evaluated at different temperatures revealed the formation of intertwined carbon filaments. The results showed that increasing in reaction temperature decreased the diameters of nanofibers and increased the formation of encapsulating carbon.
Mehran Rezaei,Mohammad Hossein Aboonasr Shiraz,Fereshteh Meshkani 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12
Mesoporous nanocrystalline nickel-alumina promoted catalysts with high surface area were prepared by microemulsion (ME) method and employed in dry reforming of methane reaction. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller surface area analysis (BET), temperature programmed reduction (TPR) and temperature programmed oxidation (TPO) techniques. The results showed that the prepared catalysts had high porosity with great surface area and small crystallite size. Among the K2O, MgO, CaO and BaO promoters, the MgO promoter showed considerable effect on catalytic performance and coke suppression of catalyst.
Mehran Rezaei,Ramin Khaghani,Saeid Moharramipour 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.4
The German cockroach, Blattella germanica (L.) (Blattodea: Blattellidae), has been recognized as a serious health problem because of its potential to harbor and transmit human disease-causing pathogens. The development of new and environmentally friendly control agents is essential as alternative tool to conventional chemical insecticides. The aim of the current study was to determine the fumigant and contact toxicity of essential oils (EOs), Artemisia sieberi Besser, Eucalyptus camaldulensis Dehn. and Thymus persicus (Ronniger ex Rech. f.) and cold press oil of Eruca sativa (Miller) (ESO) against first instar nymphs and adults. According to results, the LC 50 values of EOs were between 15.01 and 28.80 μl/l air for fumigant toxicity, 2202.8 and 5600.2 mg/l for dipping toxicity and 9484.2 and 34,421.1 mg/l for applied surface toxicity. Fumigant activity of the oils were significantly more toxic than other methods. In general, the toxicity of A. sieberi was higher than other EOs. Also, the first instar nymphs were more susceptible than adults. Additionally, the results showed that the EOs were significantly more toxic than ESO in both fumigant and dipping methods. In addition to contact effects, the fumigant activity of ESO was proved, although the toxicity was lower than the EOs. Hence, it is important to consider the production cost benefit of ESO in comparison with the EOs. So, the ESO could be considered as a good candidate in control of the cockroach but in enclosed spaces such as inaccessible cockroach hiding places, the EO of A. sieberi can be useful.
Mehran Vagheian,Dariush Rezaei Ochbelagh,Morteza Gharib 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.5
A new moving-mesh Finite Volume Method (FVM) for the efficient solution of the two-dimensionalneutron diffusion equation is introduced. Many other moving-mesh methods developed to solve theneutron diffusion problems use a relatively large number of sophisticated mathematical equations, andso suffer from a significant complexity of mathematical calculations. In this study, the proposed methodis formulated based on simple mathematical algebraic equations that enable an efficient mesh movementand CV deformation for using in practical nuclear reactor applications. Accordingly, a computationalframework relying on a new moving-mesh FVM is introduced to efficiently distribute the meshesand deform the CVs in regions with high gradient variations of reactor power. These regions of interestare very important in the neutronic assessment of the nuclear reactors and accordingly, a higher accuracyof the power densities is required to be obtained. The accuracy, execution time and finally visual comparison of the proposed method comprehensivelyinvestigated and discussed for three different benchmark problems. The results all indicated a higheraccuracy of the proposed method in comparison with the conventional fixed-mesh FVM.
On general $(\alpha,\beta)$-metrics with isotropic $E$-curvature
Mehran Gabrani,Bahman Rezaei 대한수학회 2018 대한수학회지 Vol.55 No.2
General $(\alpha,\beta)$-metrics form a rich and important class of Finsler metrics. In this paper, we obtain a differential equation which characterizes a general $(\alpha,\beta)$-metric with isotropic $E$-curvature, under a certain condition. We also solve the equation in a particular case.
ISOTROPIC MEAN BERWALD FINSLER WARPED PRODUCT METRICS
Mehran Gabrani,Bahman Rezaei,Esra Sengelen Sevim 대한수학회 2023 대한수학회보 Vol.60 No.6
It is our goal in this study to present the structure of isotropic mean Berwald Finsler warped product metrics. We bring out the rich class of warped product Finsler metrics behaviour under this condition. We show that every Finsler warped product metric of dimension $n\geq 2$ is of isotropic mean Berwald curvature if and only if it is a weakly Berwald metric. Also, we prove that every locally dually flat Finsler warped product metric is weakly Berwaldian. Finally, we prove that every Finsler warped product metric is of isotropic Berwald curvature if and only if it is a Berwald metric.
ON GENERAL (α, β)-METRICS WITH ISOTROPIC E-CURVATURE
Gabrani, Mehran,Rezaei, Bahman Korean Mathematical Society 2018 대한수학회지 Vol.55 No.2
General (${\alpha},\;{\beta}$)-metrics form a rich and important class of Finsler metrics. In this paper, we obtain a differential equation which characterizes a general (${\alpha},\;{\beta}$)-metric with isotropic E-curvature, under a certain condition. We also solve the equation in a particular case.