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Variation of XCO_(2) anomaly patterns in the Middle East from OCO-2 satellite data

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International Journal of Digital Earth 2022年第1期15卷 1219-1235页

作者： Foroogh Golkar seyed Mohsen Mousavi Department of Water Engineering&Oceanic and Atmospheric Research Centre College of AgricultureShiraz UniversityShirazIran Department of Environmental Planning and Design Shahid Beheshti UniversityTehranIran

The anthropogenic CO_(2) emission is contributed to the rapid increase in CO_(2) *** the current study the anthropogenic CO_(2) emission in the Middle East(ME)is investigated using 6 years columnaveraged CO_(2) dry air mole fraction(XCO_(2))observation from Orbiting Carbon Observatory-2(OCO-2)*** this way,the XCO_(2) anomaly(DXCO_(2))as the detrended and deseasonalized term of OCO-2XCO_(2) product,was computed and compared to provide the direct spacebased anthropogenic CO_(2) emission *** a result,the high positive and negative DXCO_(2) values have corresponded to the major sources such as oil and gas industries,and growing seasons over ME,***,the Open-source Data Inventory for Anthropogenic CO_(2)(ODIAC)emission and the gross primary productivity(GPP)were utilized in exploring the DXCO_(2) relation with human and natural driving *** results showed the capability of DXCO_(2) maps in detecting CO_(2) emission fluctuations in defined periods were detectible in daily to annual *** simplicity and accuracy of the method in detecting the man-made and natural driving factors including the main industrial areas,megacities,or local changes due to COVID-19 pandemic or geopolitical situations as well as the vegetation absorption and biomass burning is the key point that provides the environmental managers and policymakers with valuable and accessible information to control and ultimately reduce the CO_(2) emission over critical regions.

关键词： Greenhouse gas remote sensing CO_(2)emission ODIAC GPP

Stability and thermal conductivity of water-based carbon nanotube nanofluids

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Particuology 2015年第5期13卷 59-65页

作者： Mansoor Farbod Ameneh Ahangarpour seyed Gholamreza Etemad Department of Physics Shahid-Chamran University Department of Chemical Engineering Isfahan University of Technology

Water-based nanofluids were prepared with multi walled carbon nanotubes （MWCNTs） of different lengths in concentrations of 0,1,0,25 and 0,5 vol%, To improve their dispersibility, pristine MWCNTs were functionalized and cut into small lengths by reflux in an oxidizing mixture of 3：1 sulfuric and nitric acids, The initial length of the carbon nanotubes （CNTs; 10-15 μm） was reduced to 203, 171 and 134nm after 1, 2 and 4 h of reflux, respectively, Surface modification and the reduced length of the CNTs, improved the stability of the nanofluids with no significant sedimentation observed after 80 days. Furthermore, the thermal conductivities of nanofluids prepared using refluxed CNTs, were higher than that of the pristine CNTs. The thermal conductivity also increased with the nanofluid temperature, The nanofluid prepared with 1 h refluxed CNTs had the highest thermal conductivity, The enhanced thermal conductivity and stabilitv of the nanofluids was attributed to the decreased length of CNTs.

关键词： Nanofluids Thermal conductivity Stability Carbon nanotubes Refluxing time

Design of Second Order Sliding Mode and Sliding Mode Algorithms:A Practical Insight to DC-DC Buck Converter

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IEEE/CAA Journal of Automatica Sinica 2017年第3期4卷 483-497页

作者： seyed Mehdi RakhtAla Monazzahalsadat Yasoubi Hassan HosseinNia Department of Electrical Engineering Golestan University Department of Electrical and Computer Engineering Concordia University Department of Precision and Microsystem Engineering Delft University of Technology

This paper presents a simple and systematic approach to design second order sliding mode controller for buck *** second order sliding mode control(SOSMC)based on twisting algorithm has been implemented to control buck switch mode *** idea behind this strategy is to suppress chattering and maintain robustness and finite time convergence properties of the output voltage error to the equilibrium point under the load variations and parametric *** addition,the influence of the twisting algorithm on the performance of closed-loop system is investigated and compared with other algorithms of first order sliding mode control such as adaptive sliding mode control(ASMC),nonsingular terminal sliding mode control(NTSMC).In comparative evaluation,the transient response of the output voltage with the step change in the load and the start-up response of the output voltage with the step change in the input voltage of buck converter were *** results were obtained from a hardware setup constructed in ***,for all of the surveyed control methods,the theoretical considerations,numerical simulations,and experimental measurements from a laboratory prototype are compared for different operating *** is shown that the proposed twisting method presents an improvement in steady state error and settling time of output voltage during load changes.

关键词： DC-DC buck converter non-singular-terminal sliding mode second order sliding mode twisting algorithm

Contribution of tuned liquid column gas dampers to the performance of offshore wind turbines under wind, wave, and seismic excitations

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Earthquake Engineering and Engineering Vibration 2016年第3期15卷 551-561页

作者： Khosrow Bargi Reza Dezvareh seyed Amin Mousavi School of Civil Engineering College of Engineering University of Tehran

The main intention of the present study is to reduce wind, wave, and seismic induced vibrations of jacket- type offshore wind turbines （JOWTs） through a newly developed vibration absorber, called tuned liquid column gas damper （TLCGD）. Using a Simulink-based model, an analytical model is developed to simulate global behavior of JOWTs under different dynamic excitations. The study is followed by a parametric study to explore efficiency of the TLCGD in terms of nacelle acceleration reduction under wind, wave, and earthquake loads. Study results indicate that optimum frequency of the TLCGD is rather insensitive to excitation type. In addition, while the gain in vibration control from TLCGDs with higher mass ratios is generally more pronounced, heavy TLCGDs are more sensitive to their tuned frequency such that ill-regulated TLCGD with high mass ratio can lead to destructive results. It is revealed that a well regulated TLCGD has noticeable contribution to the dynamic response of the JOWT under any excitation.

关键词： offshore wind turbine wind load wave load seismic load tuned liquid column gas damper

Unraveling a Driven Damped Harmonic Oscillator through Entangled State Representation

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Chinese Physics Letters 2013年第11期30卷 22-24页

作者： seyed Mahmoud Ashrafi Mohammad Reza Bazrafkan Department of Physics Faculty of ScienceI.K.I.UniversityQazvinIran

Employing the thermo-entangled state representation,the common eigenstates of relative position and the total momentum of a two-mode system,we solve the master equation of a damped harmonic oscillator driven by a time... 详细信息

关键词： field momentum harmonic

Establishment of a calibration curve for an isocentric cobalt unit using Monte Carlo simulation

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Nuclear Science and Techniques 2017年第9期28卷 21-24页

作者： seyed Milad Vahabi Mojtaba Shamsaie-Zafarghandi Department of Energy Engineering and Physics Amirkabir University of Technology 424 Hafez Ave P.O. Box 15875-4413 Tehran Iran

Measurement of dose distribution in patients during radiotherapy is impossible. The Monte Carlo simulation is an alternative method for dose calculations. In routine radiotherapy, the source-to-surface distance(SSD)method is not practical for an isocentric unit because it requires numerous values of tissue–air ratios and inverse square law. Therefore, this method is time consuming. In this paper, the curves of relative depth doses were obtained for three different SSDs using the MCNP4C Monte Carlo simulation and approximated with a single curve called calibration curve. This curve was compared to the curve obtained by published data, differing in approximately 5% in the worst case. It was also observed that the obtained results were more accurate for distances between-5 and 10 cm from source-to-axis distance.

关键词：校准曲线蒙特卡罗模拟蒙特卡洛模拟单位平方反比定律剂量分布放射治疗剂量计算

Ce-promoted Mn/Na_2 WO_4/SiO_2 catalyst for oxidative coupling of methane at atmospheric pressure

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Journal of Natural Gas Chemistry 2010年第1期19卷 47-53页

作者： seyed Mehdi Kamali Shahri Ali Nakhaei Pour Research Institute of Petroleum Industry (RIPI) National Iranian Oil Company P. O. Box 18745-4163 Tehran Iran

A series of Ce-promoted Mn-Na2WO4/SiO2 catalysts were prepared by incipient wetness impregnation method, and their catalytic performance for oxidative coupling of methane （OCM） was investigated at atmospheric pressure in a micro-quartz-tube reactor. The catalysts were characterized by X-ray diffraction （XRD）, temperature program reduction （TPR） and BET surface area. Ce promoter increased surface area and Na2WO4 species dispersion, which enriched the amount of the surface species. In addition, Ce promoter increased the Na/W species reduction, but the reduction peak shifted to higher temperature. Stability test of 5wt%Ce catalyst indicated suitable performance and stability. The selectivity and yield of C^2＋ hydrocarbons after 50 h operation reached 65.5% and 19.6%, respectively, at 840 ℃ over 5wt%Ce-2wt%Mn5wt%Na2WO4/SiO2 catalyst.

关键词： oxidative coupling of methane CeO2 promoter Mn/Na2WO4/SiO2

Synthesis and stability evaluation of hierarchical silicoaluminophosphates with different structural frameworks in the methanol to olefins process

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Particuology 2018年第2期16卷 43-53页

作者： seyed Hesam Mousavi Shohreh Fatemi Marian Razavian School of Chemical Engineering College of Engineering University of Tehran P.O. Box 11365 4563 TehranIran

Silicoaluminophosphates （SAPOs） with different pore structures were synthesized through the implementation of polyethylene glycol （PEG） as a mesopores impregnation agent. Using PEGs with different molecular weights （MWs） and concentrations in the synthesis precursor, several samples were synthesized and characterized. Applying a PEG capping agent to the precursors led to the formation of tuned mesopores within the microporous matrix of the SAPO. The effects of the PEG molecular weight and PEG/Al molar ratio were investigated to maximize the efficiency of the catalyst in the methanol-to-olefin （MTO） process. Using PEG with a MW of 6000 resulted in the formation of both Zeolite Rho and chabazite structural frameworks （i.e., DNL-6 and SAPO-34）. Pure SAPO-34 samples were successfully prepared using PEG with a MW of 4000. Our results showed that the PEG concentrations affect the porosity and acidity of the synthesized materials. Furthermore, the SAPO-34 sample synthesized with PEG （MW of 4000） and a PEG/Al molar ratio of 0.0125 showed a superior catalytic stability in the MTO reaction owing to the tuned bi-modal porosity and tailored acidity pattern. Finally, through reactivation experiments, it was found that the catalyst is stable even after several regeneration cycles.

关键词： Hierarchical SAPO-34 PEG Mesoporosity DNL-6 zeolite MTO process Catalytic stability

Seismic reliability assessment of a steel moment-resisting frame with two different ductility levels using a cloud analysis approach

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 171-185页

作者： seyed Bahram Beheshti Aval Amir Masoumi Verki Department of Civil Engineering K.N.Toosi University of Technology

A cloud method for generating percentile engineering demand parameter versus intensity measure(EDP-IM) curves of a structure subjected to a set of synthetic ground motions is presented. To this end, an ensemble of synthetic ground motions based on available real ones is generated. This is done by using attenuation relationships, duration and suitable Gutenberg-Richter relations attributed to the considered seismic hazard at a given site by estimating a suitable distribution of magnitude and site to source distance. The study aims to clarify the significance of the duration and frequency content on the seismic performance of structures, which were not considered in developing percentile incremental dynamic analysis(IDA) curves. The collapse probabilities of two steel moment-resisting frames with different ductility levels generated by IDA and the proposed cloud method are compared at different intensity levels. When compared with conventional IDA, the suggested cloud analysis(SCA) methodology with the same run number of dynamic analyses was able to develop response hazard curves that were more consistent with site-specific seismic hazards. Eliminating the need to find many real records by generating synthetic records consistent with site-specific seismic hazards from a few available recorded ground motions is another advantage of using this scheme over the IDA method..

关键词： cloud analysis (CA) multiple-strip analysis (MSA) incremental dynamic analysis (IDA) synthetic ground motions