توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Long term static modeling of Arak refinery hydrogen plant and prediction of temperature and conversion profiles in the reformer tube
نویسنده(ها): ، ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۹
This paper describes steady–state modeling of Arak Refinery Hydrogen Plant (ARHP). Extensive refinery data consisting of temperatures and partial pressures of inlet and outlet gases of the reformer were collected over a five–year period. A one dimensional pseudo–homogeneous reactor model comprising of Langmuir–Hinshelwood–Hougen–Watson (LHHW) reaction kinetic has been developed. The model parameters were optimized using the fresh catalyst refinery data and the validated model was used to predict the ARHP conversions and temperature profiles in the reformer tube. Parametric sensitivity analysis involving the effect of inlet gas temperature, inlet flow rate of gas, reactor pressure, diameter of tube on conversion of methane and the reformer tube temperature profile are presented.<\div>

۲Comparison between Backpropagation, Elman and Radial Basis Function (RBF) networks in modeling of Tehran refinery hydrocracking unit
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۶
Different Artificial Neural Networks for modeling the hydrocracking process were utilized and their abilities were compared. The input–output data for the training and simulation phases of the networks were obtained from the Tehran refinery ISOMAX unit. Backpropagation, Elman and Radial Basis Function (RBF) networks were used for modeling and simulation of the hydrocracking unit. For each network model several architectures were studied and the best parameters for each network were obtained. The trained networks predict the yields of products of the ISOMAX unit(diesel, kerosene, light naphtha and heavy naphtha) with good accuracy. The residual error (root mean squared difference), coefficient correlation and run time, are three criteria that have been used for selection of the best network for modeling the hydrocracking unit.<\div>

۳Sonochemical synthesis of the nano particles lead (II) coordination polymers as precursors for preparation of lead (II) oxide nanoparticles
اطلاعات انتشار: اولین همایش ملی نانومواد و نانو تکنولوژی، سال
تعداد صفحات: ۵
Nano–structures of lead (II) synthesis from lead (II) coordination polymers, [Pb4L6(NO3)]n(1) and [Pb2L2I2]n(2) (L=8–hydroxyquinolin) by sonochemical method and characterized by scanning electron microscopy (SEM), X–ray powder diffraction, elemental analyses and IR spectroscopy.Solvents effect on size and morphology of nano–structuredcompound 1 and 2 have been studid.Calcination of the nano–sized compound 1 and 2 at 400 c under air atmosphere yields PbO structures.The PbO nano particles were characterized by SEM.<\div>

۴the importance of the precursor to prepare high temperature water –gas shift reaction catalysts
اطلاعات انتشار: پانزدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۴
Fe–Cr–Cu catalysts were prepared and studied in regard to their performance in the high–temperature water–gas shift reaction (HTS), which is the key step of hydrogen and ammonia industrial plants. In this work, the effect of the precursor on the activity of magnetite–based catalysts prepared by precipitating a composition containing divalent and trivalent iron compounds and a modifier trivalent chromium with a base, was studied in terms of CO conversion. The production of catalysts in their active form avoids the step of activation prior to use, in industrial processes. Sulfates and chlorides were the selected precursors. A commercial Fe–Cr based WGS catalyst was used for comparison. Catalysts were characterized using BET surface area measurements, temperature–programmed reduction (TPR) and X–ray fluorescence (XRF). According to the obtained results, the materials prepared with sulfate showed lower specific surface areas but they were more active than those obtained from chloride and the commercial one and there were three reduction peaks for all the samples in TPR results<\div>

۵the effect of primary solution concentration and co –precipitation rate on mthanol synthesis catalyst
اطلاعات انتشار: پانزدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۵
Three Cu\Zn\Al catalyst samples were prepared by a co–precipitation method by changing the concentration of the initial solution and also presiptation speed. The catalysts were characterized by BET surface area, X–ray diffraction (XRD) and temperature programmed reduction (TPR) measurement techniques. All catalysts were tested for methanol synthesis activity in fixed–bed reactor under conditions similar to that of commercial operation. In this study, methanol synthesis catalysts have been made using more concentrated solutions and also higher precipitation rate and their performance was compared with a reference catalyst. Increase of concentration of primary solutions and high speed copercipitation decreased catalyst performance slightly but catalysts produced to the this methods still had relatively adequate performance compare industrial catalysts<\div>

۶Combination of Composite Nonlinear Feedback and Adaptive Integral Sliding Mode Controllers for Robust Attitude Stabilization of a Fighter Aircraft
نویسنده(ها): ،
اطلاعات انتشار: همایش یافته های نوین در هوافضا و علوم وابسته، سال
تعداد صفحات: ۹
The problem of attitude stabilization of a fighter aircraft is investigated is this paper. The practical aspects of a real physical system like existence of external disturbances with unknown upper bound and actuator saturation are considered in the process of controller design of this aircraft. In order to design a robust autopilot in the presence of the actuator saturation, the Composite Nonlinear Feedback (CNF) controller along with the Adaptive Integral Sliding Mode (AISM) controller, that is called AISM–CNF control method, is used. The CNF part is used to stabilization of the nominal system and also the improvement the transient performance by considering the actuator saturation. The AISM part guarantees robustness against the disturbances. By the AISM controller the upper bounds of the disturbances are estimated and therefore the basic knowledge of the upper bound of the disturbances is not needed. The total controller satisfies the constraint on the input in the specific region of the state space. Finally, simulation results show the performance of the AISM–CNF controller in term of stabilization, robustness, and the good characteristics of the transient responses of the autopilot system in spite of actuator saturation.<\div>

۷Osmoregulatory capabilities of Zander (Sander lucioperca) fingerlings in different salinities of the Caspian Sea
نویسنده(ها): ، ، ،
اطلاعات انتشار: IRANIAN JOURNAL OF FISHERIES SCIENCES، سيزدهم،شماره۲، Apr ۲۰۱۴، سال
تعداد صفحات: ۲۹
Osmoregulation capabilities of two size groups (1 and 2g) of zander , Sander lucioperca, fingerlings were investigated survival rate, plasma osmolarity, sodium (Na+), chloride (Cl–) ion concentrations and cortisol level within 0, 6, 24, 72 and 240 h after abrupt transfer from freshwater to 7 and 12‰ salinity. Also, some hematological parameters were measured at 240h. The plasma osmolarity and ion concentrations (Na+, Cl–) increased immediately after the transference to 7 and 12‰ salinity, reaching maximum at 72h in 1g and at 24 h in 2g fingerlings, and significantly decreased at 240 h, while the freshwater control group maintained almost constant during 10 days which showed lower than the salinity groups. The pattern of cortisol level changes was similar in two size groups after exposure to different salinities and it reflected stress of handling. There were no significant differences between hematological values of two salinity treatment groups than the freshwater control at 240h. The result showed, not only 2g zander fingerlings acted better than 1g in faced with salinity but also the fingerlings weighing 1g could survived and tolerate Caspian Sea water salinity up to 12‰. It is suggested that the release of zander weighing from 1g would help to restocking management of this species in the southern Caspian Sea.
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