توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Rhodium\Iridium complex Catalyzed Methanol Carbonylation:Study the Effects of Various Parameters on Carbonyl Impurities Concentration
اطلاعات انتشار: دوازدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۱۲
Acetic acid is an important industrial commodity chemical that prepared by various methods. Among currently employed processes one of the most useful commercially is the Celanese acid optimization (AO) method. In this research, we evaluated the AO process flow sheet based on a simulation by Hysis 3.1 and then studied the effect of various parameters on production of by products. The results show that the increasing the concentration of carbon monoxide causes the increasing the formation of propionic acid instead the acetaldehyde. Achieved results have shown a maximum point for acetaldehyde in 40% w\w of Carbon monoxide feed. Study the effects of methanol and lithium iodide concentration show that the increasing of methanol up to 30% w\w causes the increasing by–product concentration instead lithium iodide. Investigation of water content in 2–5% w\w shows that increasing of water content causes to increasing of propionic acid concentration instead of acetaldehyde.<\div>

۲Application of 0–1 Fuzzy Programming in Optimum Project Selection
نویسنده(ها): ، ،
اطلاعات انتشار: پنجمین کنفرانس بین المللی مدیریت پروژه، سال
تعداد صفحات: ۷
In this article, a mathematical programming model for choosing an optimum portfolio of investments is developed. The investments are considered as investment projects. The uncertainties of the real world are associated through fuzzy concepts for coefficients of the proposed model (i. e. initial investment costs, profits, resource requirement, and total available). Model has been coded by using LINGO 11.0 solver. The results of a full analysis of optimistic and pessimistic derivative models are promising for selecting an optimum portfolio of projects in presence of uncertainty.<\div>

۳Avoiding of Resonance Over Voltage Under Off–State Condition of Hybrid Active Power Filter by an Active Resistive Damper
نویسنده(ها): ،
اطلاعات انتشار: بیست و ششمین کنفرانس بین المللی برق، سال
تعداد صفحات: ۱۱
Powerline communication(PLC) is one of the latest progressive technology in the field of communication. It has many advantages if it is commonl This paper presents a hybrid active power filter (HAPF) comprising an active resistive damper (ARD). The ARD can damp over voltage or over current under resonance condition, when the active part of the HAPF (inverter) is disconnected from the grid due to electrical or non–electrical failure. Whereas the electronic switches are employed in the ARD, the proposed topology can response to damping of over voltage or over current rapidly. The control method of the ARD is presented in this paper too. Also the magnitude–frequency characteristics of the HAPF and control method of the HAPF based on source current detection strategy are of the HAPF are presented with and without the ARD in this paper. Finally the simulation results are provided to validate the proposed topology analyzed in detail. Analysis and investigation<\div>

۴Control of b–Shape C–Type Hybrid Active Power Filter Based on State–Space Variables
نویسنده(ها): ،
اطلاعات انتشار: بیست و ششمین کنفرانس بین المللی برق، سال
تعداد صفحات: ۹
A control method of hybrid active power filter (HAPF) based on state–space variables and equations is proposed in this paper. The statespace equations are extracted by the averaged model of the HAPF comprising an inverter, fifth and seventh passive filters. Whereas the inverter control signals of the HAPF are extracted by the state–space variables, the output currents of the inverter are controlled effectively. The principles of the proposed control method are examined for compensation of the load harmonic currents. The presented control method was simulated and the simulation results are provided to show validation of proposed control method.<\div>

۵Analysis and performance Evaluation of trapezoidal filter in pulse shaping
نویسنده(ها): ، ،
اطلاعات انتشار: پنجمین کنفرانس بین المللی پیشرفتهای علوم و تکنولوژی، سال
تعداد صفحات: ۶
The Implementation and realization of a digital pulse processor depends on the complexity of its software algorithms. Therefore, it is better to have simpler algorithms so that the possibility of straightaway use of them is provided. Based on recursive algorithms for real–time digital pulse shaping, exponential pulse is amplified and then digitized. Digital data are deconvolved and this deconvolved pulse is processed by a time–invariant digital filter which allows trapezoidal\triangular output pulse to be synthesized. Pulse shaping techniques used in trapezoidal filter are analyzed through MATLAB program. The new experiment shows how changes in parameters of pulse shaping algorithms affects the output waveform.<\div>

۶Three–Level NPC Inverter Control System of Hybrid Active Power Filter by Modulation Ratios of Switching Functions
نویسنده(ها): ،
اطلاعات انتشار: هفدهمین کنفرانس سراسری شبکه های توزیع نیروی برق، سال
تعداد صفحات: ۱۵
For harmonic compensation, a control system of a four–wire three–level NPC inverter employedin a hybrid active power filter (HAPF) based on modulation ratios of switching functions is proposed in thispaper. The inverter and two parallel passive filters (PPFs) tuned in 5th and 7th orders of harmonic currentsform the HAPF. The PPFs are used for compensating of average reactive power of loads and filtering of 5thand 7th orders of harmonic currents to decrease rated power of the inverter. The switching functions of theinverter control system are extracted based on compensation of variable load reactive power and the ordersof harmonic currents with exception of 5th and 7th orders. The averaged model of the inverter is extracted bypossible switching states of the inverter’s IGBTs. The proposed control method is applicable underasymmetrical non–sinusoidal source and non–linear loads conditions .The principles of the presented controlmethod are analyzed in this paper too. The proposed control method was simulated and the simulationresults are provided to validate effectiveness of the proposed control method.<\div>

۷Pushing the limits in hydraulic fracture design with a P–3D model and non–Darcy flow effect consideration
نویسنده(ها): ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۱۶
With the onset of hydraulic fracturing an applicable development method for production from gas wells– high or low permeable– was introduced, with fracture parameters optimization being the mainstay for the hydraulic fracturing design. In this study, a method for optimizing fracture parameters is introduced based on the Unified Fracturing Design (UFD. Thereafter, the maximum dimensionless productivity index and optimal dimensionless fracture flow conductivity are calculated for a certain proppant number in a fractured well. The calculations are followed by determining the corresponding dimensionless productivity index, the optimal half–length and the width of the fracture.Assuming a constant fracture height, the calculations become easy and a 2D fracture model would suffice to design it. But, it is not constant throughout the fracture and varies with the net pressure exerted on the fracture medium. All calculations above are carried out taking into account the effect of non–Darcy flow in the fracture with not only the fracture width and length, but also the fracture height being optimized. Considering these two issues, the effects of design parameters on the production from a hydraulically fractured well are investigated<\div>

۸Effects of dietary prebiotic MHF–Y and starvation on the compensatory growth, survival, and some hematological parameters in common carp Cyprinus carpio fry
نویسنده(ها): ، ، ،
اطلاعات انتشار: کنفرانس بین المللی پژوهش های نوین در علوم کشاورزی و محیط زیست، سال
تعداد صفحات: ۹
This study aimed to determine the effects of dietary prebiotic Mito (MHF–Y) on compensatory growth common carp Cyprinus carpio fry (n= 300; 4.5 ± 0.05 g) following one week starvation. The experiment was conducted within 60 days with three triplicate treatments: a control fed with non–prebiotic diet with no starvation period (T1), a 2nd group starved for one week then fed 2.0 g of prebiotic per kg diet (T2), and the 3rd one received no prebiotic following one week starvation (T3). The results showed the highest final weight and length in the control followed by T2 (P< 0.05). T1 and T2 gained the greatest (0.81 ± 0.00 and 0.57 ± 0.01 d−1, respectively) specific growth rate (SGR). The condition factor significantly increased (1.8 ± 0.11) in T3 while T1 and T2 were not different in this respect (P > 0.05). The lowest (2.26 ± 0.02 and 2.59 ± 0.1) feed conversion ratio (FCR) and highest (1.2 ± 0.04 and 1.38 ± 0.01) protein efficiency ratio (PER) were recorded in T1 and T2, respectively. Numbers of red blood cells were similar in the three treatments (P > 0.05). Hemoglobin and hematocrit were utmost in T3 and T1, respectively. T2 contained the highest (13800 ± 600) number of white blood cells (WBC). The treatments were not different in WBC differential counts of basophils, eosinophils, and monocytes. The greatest (77.59 ± 1.00) and lowest (74.33 ± 0.57) amounts of lymphocytes, respectively, were detected in T2 and T1. The results show that the addition of 2% of prebiotic Mito in the diet of carp fry could not improve their growth performance, it, however, could give rise to better results compared with T3 that fed no prebiotic after starvation; in addition, the fry in T2 showed the best results concerning improved immunity.<\div>

۹Anti–inflammatory effect of Prunus armeniaca L. (Apricot) extracts ameliorates TNBS–induced ulcerative colitis in rats
نویسنده(ها): ، ، ، ،
اطلاعات انتشار: Research in Pharmaceutical Sciences، نهم،شماره۴(پياپي ۲۵)، ۲۰۱۴، سال
تعداد صفحات: ۷
Prunus armeniaca L. (Apricot) is a tree cultivated in different parts of the world. Apricot kernel as a good dietary supplement has shown antioxidant, anti–inflammatory and other pharmacologic properties which suggest that it may be functional as an anticolitis agent. In this study we evaluated the effects of apricot kernel extract and oil on ulcerative colitis in rats. Rats were fasted for 36 h before the experiment. Colitis was induced by intra–rectal instillation of 50 mg\kg trinitrobenzene sulfonic acid in male Wistar rats. Treatments were started 6 h after colitis induction and continued every 24 h for 5 days. Apricot kernel extract (100, 200, 400 mg\kg p.o. and 100, 400 mg\kg i.p.) and apricot kernel extract\oil (100, 200, 400 mg\kg p.o.) were used as experimental treatments and prednisolone (4 mg\kg p.o. or i.p.) was used as reference drug. On the day 6, colon tissue was removed and macroscopic and pathologic parameters were evaluated. Ulcer index and total colitis index as representative of macroscopic and histologic parameters respectively showed ameliorating effects in experimental groups especially those treated by intraperitoneal administration route. Results also demonstrated that oil fraction was not able to potentiate the effects of extract. These data suggest that apricot kernel extracts (with or without oil) can be introduced for further mechanistic and clinical studies as a complementary medicine for inflammatory bowel disorders.
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