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Design of on-board calibration methods for a digital sun sensor based on Levenberg–Marquardt algorithm and Kalman filters

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Chinese Journal of Aeronautics 2020年第1期33卷 339-351页

作者： Ali RAHDAN hossein BOLANDI Mostafa ABEDI Department of Electrical Engineering Iran University of Science&TechnologyTehran ***Iran Department of Electrical Engineering Shahid Beheshti UniversityTehran ***Iran

Digital sun sensor is one of the most important sensors used in the Attitude Determination System(ADS)of the *** to the harsh environmental conditions that exist in the space,various distortions may occur in the sun sensor optical system that lead to the reduced accuracy of this ***,it is necessary to recalibrate the optical parameters of the aforementioned *** this purpose,first a novel attitude independent error model is proposed for the SS-411 sun sensor that includes the central point of the CCD array,installation error,filter thickness and sensor ***,the mutual interfaces between the sensor parameters are considered in the developed *** order to extract the sensor parameters,a nonlinear optimization technique called the Levenberg–Marquardt is applied to the developed model as a batch *** addition,the Extended Kalman Filter(EKF)and the Unscented Kalman Filter(UKF)have been utilized as sequential *** will be shown that by considering a worst case of variation amount for sensor parameters,an accuracy improvement of about 17°is achieved by the developed calibration *** between the developed algorithms represents that UKF has higher accuracy,shorter time convergence but higher computational load.

关键词： Digital sun sensor Extended Kalman filter Levenberg–Marquardt On-board calibration Unscented Kalman filter

A blockchain maturity model in agricultural supply chain

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Information Processing in Agriculture 2021年第3期8卷 398-408页

作者： Mohammad hossein Ronaghi Department of Management Shiraz UniversityShirazIran

Blockchain technology is a disruptive technology that changes business and supply chain *** distributed software architecture and advanced computing,blockchain can change the way information is exchanged between actors in the *** technol-ogy provides a platform for solving the problem of tracking product information in supply chain ***,the present study aims to provide a model for evaluating the maturity of blockchain technology in the agricultural supply *** present research is applied that has been done in three *** the first phase,the dimensions of the blockchain are ranked by agricultural experts using the SWARA *** research experts are 13 faculty members of the department of agriculture active in the field of technology *** the second phase,a model is designed to evaluate blockchain maturity using each dimension of blockchain technology and maturity *** the third phase,the proposed model is tested using data collected by a questionnaire in the supply chain of a company active in the agriculture *** research findings show that smart contracts,Internet of Things(IoT),and transaction records are of the highest impor-tance among the blockchain ***,the supply chain under study is in a good condition in digital ***,the originality aspect of the research is that it determines the importance of blockchain dimensions in the field of agriculture and from an applied point of view,it introduces the maturity model of blockchain in supply chain management.

关键词： Blockchain Agricultural supply chain Maturity model SWARA

A New Evaluation Criterion for Optimizing the Mechanical Properties of Toughened Polypropylene/Silica Nanocomposites

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Chinese Journal of Polymer Science 2020年第8期38卷 877-887,I0008页

作者： hossein Pourrahmani Mona Golparvar Mohammad Fasihi Group of Energy Materials (E)cole Polytechnique Fédérale de LausanneSion 1951Switzerland School of Chemical Petroleum and Gas EngineeringIran University of Science and TechnologyTehran 16846-13114Iran School of Mechanical Engineering Braunschweig university of technologyBraunschweig 38106Germany

This study aims to experiment with the mechanical properties of polypropylene(PP)/thermoplastic elastomer/nano-silica/compatibilizer nanocomposite using the melt mixing *** addition of polyolefin elastomers has proved to be an approachable solution for low impact strength of PP,while it would also reduce the Young's modulus and tensile *** is why reinforcement would be applied to this combination to enhance the elastic *** mechanical properties of the prepared composites were devised to train an artificial neural network to predict these properties of the system in 6256 unknown ***,the sensitivity analysis was performed and the share of each input parameter on the respective output values was ***,a novel parameter called nanocomposite evaluation criterion(NEC)is introduced to analyze the suitability of the nanocomposites considering the mechanical ***,the formulation with optimal mechanical properties of toughness,elongation at break,tensile strength,Young's modulus,and impact strength was obtained.

关键词： Nanocomposite Polypropylene(PP) Silica Artificial neural networks Nanocomposite evaluation criterion(NEC) Sensitivity analysis

New insight into prediction of phase behavior of natural gas hydrate by different cubic equations of state coupled with various mixing rules

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Petroleum Science 2017年第4期14卷 780-790页

作者： Amir hossein Saeedi Dehaghani Deparlment of Petroleum Engineering Faculty of Chemical EngineeringTarbiat Modares UniversityTehranlran

Progress in hydrate thermodynamic study necessitates robust and fast models to be incorporated in reservoir simulation softwares. However, numerous models presented in the literature makes selection of the best,proper predictive model a cumbersome task. It is of industrial interest to make use of cubic equations of state(EOS) for modeling hydrate equilibria. In this regard, this study focuses on evaluation of three common EOSs including Peng–Robinson, Soave–Redlich–Kwong and Valderrama–Patel–Teja coupled with van der Waals and Platteeuw theory to predict hydrate P–T equilibrium of a real natural gas sample. Each EOS was accompanied with three mixing rules, including van der Waals(vd W),Avlonitis non-density dependent(ANDD) and general nonquadratic(GNQ). The prediction of cubic EOSs was in sufficient agreement with experimental data and with overall AARD% of less than unity. In addition, PR plus ANDD proved to be the most accurate model in this study for prediction of hydrate equilibria with AARD% of *** was observed that the accuracy of cubic EOSs studied in this paper depends on mixing rule coupled with them,especially at high-pressure conditions. Lastly, the present study does not include any adjustable parameter to be correlated with hydrate phase equilibrium data.

关键词： Gas Hydrate Cubic equation of state Mixing rule Thermodynamic modeling

Dearomatization of normal paraffin by adsorption process using synthesized NaX zeolite

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Petroleum Science 2013年第3期10卷 408-414页

作者： hossein Faghihian Leila Riazi Department of Chemistry Shahreza Branch Islamic Azad University86145-311 Iran R&D Department I. C. I. I. C.Isfahan Iran

Linear alkyl benzenes （LABs） are the main materials for detergent production. The presence of aromatic compounds in this material can decrease the quality of the final product and enhance the deactivation rate of catalysts. In this research we used zeolite NaX for de-aromatization of the recycled paraffin from the alkylation unit of an LAB production complex. The effect of different parameters on the removal efficiency of adsorbent was studied and optimized. To study the re-usability of the adsorbent, the breakthrough curves were obtained by using a fixed bed column filled with the adsorbent. The results indicated that the adsorbent capacity remained unchanged after three regeneration cycles. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. It was concluded that the Langmuir model agreed well with the experimental data. The calculated thermodynamic parameters of the adsorption showed that the adsorption process was spontaneous and exothermic. The reaction rate was estimated by the pseudo-second order kinetic model.

关键词： Dearomatization LAB zeolite adsorption separation

Computational Study of Electromagnetic Fields,Eddy Currents and Induction Heating in Thin and Thick Workpieces

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Communications in Computational Physics 2010年第6期8卷 211-225页

作者： Mohammad hossein Tavakoli hossein Karbaschi Feridoun Samavat Physics Department Bu-Ali Sina UniversityHamedan 65174Iran

A set of 2D steady state finite element numerical simulations of electromagnetic fields,eddy currents distribution and induction heating pattern has been done for different thicknesses of a metal *** between the calculation results show the importance of workpiece thickness on induction heating process including electromagnetic field distribution,eddy currents pattern,heating structure and coil efficiency.

关键词： Computer simulation finite element analysis modeling induction heating metals

Molecular Structure and Theoretical Thermodynamic Study of Folic Acid Based on the Computational Approach

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Chinese Journal of Structural Chemistry 2015年第9期34卷 1307-1316页

作者： Shahla Hamedani hossein Aghaie Department of Chemistry Science and Research BranchIslamic Azad University

In our previous work, we studied the interaction of folic acid, FA, molecule with single- walled carbon nanotube and the related binding energies with other related parameters. Now, in order to extend our study with respect to the other structural properties of folic acid molecule and its thermodynamic properties, we optimized the structures of both neutral and zwitteronic forms of this molecule by using the DFT/B3LYP method in the gas phase and then in different solvents. In addition, the electronic properties, such as the molecular orbital study （HOMO, LUMO, PDOS, and TDOS） and geometrical structure, were investigated by the above-mentioned method with 6-3 l G（d） basis set. The thermodynamic properties of both neutral and zwitterionic forms of the FA molecule at different temperature have been calculated. Natural bond orbital （NBO） analysis has been done to study the stability of the molecule arising from charge delocalization.

关键词： folic acid, thermodynamic properties, DFT, NBO

Searching for α variation and cosmic acceleration in the generalized BSBM theory with tachyonic potential

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Research in Astronomy and Astrophysics 2015年第2期15卷 191-198页

作者： hossein Farajollahi Fatemeh Tayebi Department of Physics University of GuilanNamjou BLV Rasht Iran School of Physics University of New South WalesSydney NSW 2052 Australia

Abstract We consider the BSBM （Bekenstein, Sandvik, Barrow and Magueijo） cos- mological model in the presence of tachyon potential with the aim of studying the sta- bility of the model and test it against observations. The phase space analysis shows that from fourteen critical points that represent the state of the universe, only one is stable. With a small perturbation, the universe transits from a state of unstable deceleration to stable acceleration. The stability analysis combined with the best fitting process imposes constraints on the cosmological parameters that are in agreement with ob- servation. In the BSBM theory, the variation of fundamental constants is driven from variation of a scalar field. The tachyonic scalar field, responsible for both variation of fundamental constants and universal acceleration, is reconstructed.

关键词： cosmology:theory—cosmology:observations—cosmological parameters

Cadmium sorption from aqueous solutions onto Iranian sepiolite:Kinetics and isotherms

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Journal of Central South University 2013年第12期20卷 3627-3632页

作者： HOJATI Saeid KHADEMI hossein Department of Soil Science College of Agriculture Shahid Chamran University of Ahvaz Department of Soil Science College of Agriculture Isfahan University of Technology

This work aims to investigate the efficiency of Fariman sepiolite from Iran as an adsorbent to remove Cd from aqueous solutions. The effects of different experimental factors such as the initial Cd concentration, contact time and the sorbent dose were investigated through a series of batch adsorption experiments. The results show that the adsorption capacity of sepiolite for Cd increases with the contact time, the initial concentration of Cd solutions and the sorbent dose. Sorption of Cd by Fariman sepiolite is rapid within the first hour of the experiment and then slowly increases until a pseudo equilibrium is approached at 8 h. The results also show that the time-dependent Cd sorption data are better described with pseudo second-order （7〉0.999） than that of pseudo first-order （r2〉0.971） kinetic model. Equilibrium isotherm studies show that the experimental data are better correlated by the Freundlich adsorption isotherm （7〉0.995） than the Langmuir （P〉0.825）. It is suggested that both adsorption and cation exchange reactions are responsible for the sorption of Cd by the sepiolite, and the mineral has a very good potential to remove Cd from aqueous solutions.

关键词： sepiolite cadmium adsorption capacity kinetics isotherm