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Wear of MgO-C Refractories in EBT Type Furnaces Experienced at Iranian Mobarakeh Steel Plant

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China's Refractories 2002年第4期11卷 3-8页

作者： Ali Reza Rezaie Amir Reza Hanifi Farhad Golestani-Fard Dept. of Metallurgy & Materials Engineering Iran University of Science & Technology Narmak Tehran 16844 IranDept. of Metallurgy & Materials Engineering Iran University of Science & Technology Narmak Tehran 16844 IranDept. of Metallurgy & Materials Engineering Iran University of Science & Technology Narmak Tehran 16844 Iran

Mobarakeh Steel Company produces 3 million tons of steel annually with eight 180 tons EBT furnaces. Different types of magnesia-carbon refractories have been employed at slagline during last 5 years. In the present study the wear and corrosion of MgO-C refractories of these furnaces have been studied via post-mortem analysis of used bricks and the observation of operational effects. Laboratory corrosion tests were also arranged to investigate the effect of slag chemistry and the mechanism of chemical corrosion . Characterization of different magnesia-carbon bricks clarified that the crystal size , type and chemistry of magnesia as well as graphite structure have the main influence on corrosion resistance. The CaO: SiO2 ratio in slag also plays a vital role in the wear of slagline refractories. The iron oxide content of slag also has a major role in graphite oxidation. Of metallurgical parameters , the electric power input and the contact time have great influence on refractories life. The results will be discussed with emphasis on particular operational factors in Mobarakeh steel plant.

关键词： Magnesia-carbon brick Electric arc furnace Wear mechanism test Iran

Traditional Structures Technologies in Tekye-Amir-Chakhmagh

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Journal of Civil Engineering and Architecture 2010年第9期4卷 47-55页

作者： Hessam Ghamari Mohesn Vafamehr Faculty of Architecture and Urbanism lran University of Science and Technology Narmak Tehran *** Iran

Iranian traditional architecture can be identified in many of its old famous buildings in the country. The principles and specifications in these buildings show the intelligence of implemented techniques that makes them to remain stable. Thus, it is important to explore the traditional structures and architectural technologies in order to understand the reasons for this stability toward the new methods in modem architecture. Many of historical buildings in Iran have remained standing after many years and they show the deep wisdom of their architects. The purpose of this article is studying the various aspects of traditional structure and integration between this well-oriented structure and architecture. For reaching this goal, we refer to Tekye-Amir-Chakhmagh in Yazd as our case study, which is one of the most important and noticeable examples of Iranian traditional architecture. By introducing Amir-Chakhmagh Complex, we analyzed the specifications and fundamental elements that played an important role in stability and sustainability of Tekye-Amir-Chakhmagh and thereafter, we assessed the technologies that were used intelligently and intricately in this historical building. In this research, information is collected with field study and library resources. Finally, qualities and characteristics of the structure are studied by drawings and structural analysis and as conclusion, the suggestions and guidelines are presented.

关键词： Structure Iranian architecture load technology Tekye-Amir-Chakhmagh.

Synthesis of WC powder through microwave heating of WO_3–C mixture

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 202-207页

作者： Amir Karimzadeh Behnami Arman Hoseinpur Masoud Sakaki Mohammad Sh. Bafghi Kazumichi Yanagisawa School of Metallurgy and Materials Engineering Iran University of Science and Technology (IUST) Narmak Tehran 16846-13114 Iran Department of Materials Engineering Faculty of Engineering Malayer University Malayer 65719-95863 Iran Research Laboratory of Hydrothermal Chemistry Faculty of Science Kochi University Kochi 780-8073 Japan

A simple, easy, and low-cost process for the fabrication of tungsten carbide （WC） powder through microwave heating of WO3-C mixtures was developed. Thermodynamic calculations and experimental investigations were carried out for WO3-and W-C systems, and a formation mechanism was proposed. In the results, for the synthesis of WC, the use of over stoichiometric amount of C together with a spe- cially assembled experimental setup （which effectively retains heat in the system） is necessary. The WC powder is successfully obtained by heating WO3：5C mixture for 900 s in a domestic microwave oven.

关键词： tungsten carbide microwave heating carbothermic reduction thermodynamic analysis

Recurrent Polynomial Neural Networks for Enhancing Performance of GPS in Electric Systems

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Wireless Sensor Network 2009年第2期1卷 95-103页

作者： Mohammad Reza MOSAVI Associate Professor Department of Electrical Engineering Iran University of Science and Technology Narmak Iran

Global Positioning System (GPS) is a worldwide satellite system that provides navigation, positioning, and timing for both military and civilian applications. GPS based time reference provides inexpensive but highly-accurate timing and synchronization capability and meets requirements in power system fault location, monitoring, and control. In the present era of restructuring and modernization of electric power utilities, the applications of GIS/GPS technology in power industry are growing and covering several technical and man-agement activities. Because of GPS receiver’s error sources are time variant, it is necessary to remove the GPS measurement noise. This paper presents novel recurrent neural networks called the Recurrent Pi-Sigma Neural Network (RPSNN) and Recurrent Sigma-Pi Neural Network (RSPNN). The proposed NNs have been used as predictor in GPS receivers timing errors. The NNs were trained using the dynamic Back Propagation (BP) algorithm. The actual data collection was used to test the performance of the proposed NNs. The ex-perimental results obtained from a Coarse Acquisition (C/A)-code single-frequency GPS receiver strongly support the potential of the method using RPSNN to give high accurate timing. The GPS timing RMS error reduces from 200 to less than 40 nanoseconds.

关键词： Accurate Timing GPS Electric Systems Neural Networks

COPLANAR TRANSMISSION LINE EXPOSED TO ELECTROMAGNETIC FIELD

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COPLANAR TRANSMISSION LINE EXPOSED TO ELECTROMAGNETIC FIELD

Effect of Orbital Characteristic of Inclined Third-body on Motion of Secondary-body for a Hierarchical Triple Systems

IEEE 2005 International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications

作者： Ahmad Cheldavi Mohammad Khalaj-Amirhosseini Shima Abbasi College of Electrical Engineering Iran University of Science and Technology narmak Tehran I.R. IRAN College of Electrical Engineering Iran University of Science and Technology narmak Tehran I.R. IRAN College of Electrical Engineering Iran University of Science and Technology narmak Tehran I.R. IRAN

The concept of this paper is to find the voltages and currents induced by externall plane waves on a coplanar transmission line. This three dimensional problem is subdivided into two simple problems:

关键词： COPLANAR TRANSMISSION LINE EXPOSED TO ELECTROMAGNETIC FIELD

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Research in Astronomy and Astrophysics 2023年第6期23卷 1-11页

作者： Majid Bakhtiari Assistant Professor School of Advanced TechnologiesIran University of Science and TechnologyNarmakTehran 16844Iran

The influence of a third-body's orbital elements on the second-body's motion in a hierarchical triple system is a crucial problem in *** prolonged evaluation studies have focused on a distant zero-inclined *** study presents a new perspective on second-body motion equations that addresses a perturbing-body in an elliptic orbit derived with consideration of the axial-tilt(obliquity)of the *** proposed model is compared by the dual-averaged method and the N-body problem *** validation,a generalized threebody model is derived to investigate the effects of the third-body's orbital elements on secondary-body motion *** proposed model considers short-time oscillations that affect secular evaluation and applies to exoplanets with all the primary and third body eccentricities,inclinations,and mass *** is shown that the obliquity of the primary(or third-body's inclination)must be considered for precise long-term assessment,even in highly-hierarchical systems.

关键词： celestial mechanics planets and satellites:dynamical evolution and stability Planetary Systems gravitation

Modeling of hot deformation behavior and prediction of flow stress in a magnesium alloy using constitutive equation and artificial neural network(ANN)model

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Journal of Magnesium and Alloys 2018年第2期6卷 134-144页

作者： S.Aliakbari Sani G.R.Ebrahimi H.Vafaeenezhad A.R.Kiani-Rashid School of materials and metallurgical engineering Iran University of science and technology(IUST)NarmakTehranIran Materials and Polymers Engineering Department Faculty of EngineeringHakim Sabzevari UniversitySabzevarIran Department of Metallurgical and Materials Engineering Faculty of EngineeringFerdowsi university of MashhadMashhadIran

The aim of the present study was to investigate the modeling and prediction of the high temperature flow characteristics of a cast magnesium(Mg-Al-Ca)alloy by both constitutive equation and ANN *** this end,hot compression experiments were performed in 250-450℃and in strain rates of 0.001-1 s^(−1).The true stress of alloy was first and foremost described by the hyperbolic sine function in an Arrhenius-type of constitutive equation taking the effects of strain,strain rate and temperature into *** indicated that unlike low strain rates and high temperature with dominant DRX activation,in relatively high strain rate and low temperature values,the precision of the models become decreased due to activation of twinning *** that moment and for a better evaluation of twinning effect during deformation,a feed-forward back propagation ANN was developed to study the flow behavior of the investigated ***,the performance of the two suggested models has been assessed using a statistical *** comparative assessment of the gained results specifies that the well-trained ANN is much more precise and accurate than the constitutive equations in predicting the hot flow behavior.

关键词： Hot deformation Magnesium alloy Modeling Twinning Hyperbolic sine equation ANN model

Solution for generalized fuzzy fractional Kortewege-de Varies equation using a robust fuzzy double parametric approach

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Journal of Ocean Engineering and Science 2023年第6期8卷 602-622页

作者： L.Verma R.Meher Z.Avazzadeh O.Nikan Department of Applied Mathematics&Humanities S.V.National Institute of TechnologySurat 395007India Department of Applied Mathematics Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China School of Mathematics Iran University of Science and TechnologyNarmakTehran 16846-13114Iran

The nonlinear Kortewege-de Varies(KdV)equation is a functional description for modelling ion-acoustic waves in plasma,long internal waves in a density-stratified ocean,shallow-water waves and acoustic waves on a crystal *** paper focuses on developing and analysing a resilient double parametric analytical approach for the nonlinear fuzzy fractional KdV equation(FFKdVE)under gH-differentiability of Caputo fractional order,namely the q-Homotopy analysis method with the Shehu transform(q-HASTM).A triangular fuzzy number describes the Caputo fractional derivative of orderα,0<α≤1,for modelling *** fuzzy velocity profiles with crisp and fuzzy conditions at different spatial positions are in-vestigated using a robust double parametric form-based q-HASTM with its convergence *** ob-tained results are compared with existing works in the literature to confirm the efficacy and effectiveness of the method.

关键词： Fuzzy set Double parametric approach Hukuhara differentiability Shehu transform KdV equation q-HAShTM Caputo fractional derivative

Effects of Multiple Strengthening Treatments on Mechanical Properties and Stability of Nanoscale Precipitated Phases in an Aluminum-Copper-Lithium Alloy

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Journal of Materials Science & Technology 2010年第12期26卷 1078-1082页

作者： S.Ahmadi H.Arabi A.Shokuhfar Department of Material Science Faculty of EngineeringTarbiat Modares UniversityTehranIran Center of Excellence of Advanced Materials and Processing(CEAMP) Department of Metallurgy and Materials Science and EngineeringIran University of Science & Technology(IUST)NarmakTehranIran Department of Material Science Faculty of Mechanical EngineeringK.N.Toosi University of TechnologyTehranIran

Effects of multiple strengthening treatments （i.e. ag mechanical properties and stability of nanoscale prec in this research. Various tests such as hardness, tensi ng either at three or four consecutive temperatures） on pitated phases in an AA2090 alloy have been evaluated e, electrical resistance, differential scanning calorimetric （DSC）, and transmission electron microscopy （TEM） have been performed. The results show that the ultimate tensile strength （UTS） and the yield strength of the samples aged at four consecutive temperatures （i.e. natural aging＋190℃＋150℃＋100℃） can be increased approximately to 660 and 610 MPa, respectively. It is also found that precipitation of T1 phase occurs during multiple aging process of the alloy and the higher amounts of enthalpies shown in DSC charts are linked to higher volume fraction of this precipitate. Furthermore, TEM observations reveal that T1 phase has plate shape morphology and its crystal structure is in the form of hcp with lattice parameters of a=0.467 nm and c=0.878 nm.

关键词： Multiple strengthening Thermo mechanical treatment (TMT) Selected area electron diffraction (SAED) pattern Inter planar spacing (d)