The present work considers an alternative solution for a complex configuration of rotor discs by applying Galerkin Method. The theoretical model consists of elastic shaft carrying number of discs and supported on number of journal bearings. The equation of motion was discretized to finite degree of freedom in terms of the system generalized coordinates. The various effects of the dynamical forces and moments arising from the bearing, discs and shaft were included. Rayleigh beam model is used for analyzing the shaft while the discs are considered rigid . The validity and convergence of the present analysis was carefully checked by comparing with the Finite Element solution. An example of rotor consists of three different size discs and supported by two journal bearing was considered for the numerical solution .The results shows good agreements between the two methods ,where the maximum error not exceeds 5%. The convergence test showed that using few modes (not more than 6) are sufficient for the accurate analysis. The forward and backward whirl was investigated experimentally .The experimental results of a two discs rotor ,show a reasonable agreement where the maximum error not exceeds 11%. The unbalance response, Cambpell diagram, orbit response were plotted .The effects of geometry, disc sizes , location and arrangement on the unbalance response and natural frequencies of three discs rotor were further investigated .
This paper presents L1-adaptive controller for controlling uncertain parameters and time-varying unknown parameters to control the position of a DC servomotor. For the purpose of comparison, the effectiveness of L1-adaptive controller for position control of studied servomotor has been examined and compared with another adaptive controller; Model Reference Adaptive Controller (MRAC). Robustness of both L1-adaptive controller and model reference adaptive controller to different input reference signals and different structures of uncertainty were studied. Three different types of input signals are taken into account; ramp, step and sinusoidal. The L1-adaptive controller ensured uniformly bounded
... Show MoreThe accumulation of toxic elements in vegetables and melons grown in agriculture, Brassica rapa - turnip, Solanum lycopersicum - tomato, Citrullus lanatus - watermelon, Capsicum annuum - bell pepper, Daucus carota - carrots, Cucurbita pepo - pumpkin, Cucumis melo - melon, and also Prunus armeniaca - apricot from fruit trees were analyzed. The excess of maximum allowable concentrations in agricultural crops of the element As by 1.65-1.75, Cd - 1.6-2.3, Cr -1.2-2.35, Cu -1.6-3.3, Ni - 1.16-3.53, Pb - 1.54-3.08, Al - 1.36-3.5, Sb - 2.0-33, Se - 1.1-3.3 times was established. The maximum allowable concentration of mercury in vegetables and melons was equal to 0.02 mg/kg,
... Show MoreEtoricoxib (EXB) is a highly selective cox-2 inhibitor which belongs to the non-steroidal anti-inflammatory drug (NSAID). EXB is a class II drug according to the biopharmaceutical classification system (BCS), which possess a very low aqueous solubility in water. In the present study, many trials were made to improve the aqueous solubility and dissolution rate of EXB by solid dispersion technique.
Eighteenth EXB formulas were formulated as a solid dispersion using a variety of hydrophilic polymers (as carriers) including poloxamer 407 (PXM 407), poloxamer 188 (PXM 188) and polyethylene glycol 4000 (PEG 4000) at different drug: polymer ratios (1:1, 1:3 and 1:5). These formulas were prepared by two methods; solvent
... Show MoreAbstract
This research deals with studying and analysis of a poetic group under the
title (Trees behind fence) of the great poet Dr. Ahmed Sulaiman AlAhmed
who is the some of the Shek , Sulaiman Al-Ahmed who is the linguist - poet
and famous jurist member in the Arabic scientific assemble in Damascus and
brother of the great poet Badawi Al-Jabal. This poetic group include two big
poetic legends : the first one is (Trees behind fence , ) which include one
hundred and eighty four line and the second one ( AZ-Mebadia ) which is
consists of one hundred and seventy eight line, both of them from the (Al-
Camil ) meter which is free rhyme which bears a many meaning and pictures
and just the great poet composite the
During the educational practices in the Spanish department at the Faculty of Languages , University of Baghdad , we noticed that the personal pronouns in effect replaced by the direct and indirect characterized hardly be expressed , and the difficulty of her education.
Rationale: I chose this topic because the personal pronouns differ between the Spanish language and the Arabic language. We believe that this study may be useful not only for language teachers, but also for students, because it can contribute to a greater awareness of and correct weaknesses.
Objectives: To apply the model from which to address the problems in the use of personal pronouns Spanish , and the difference between effect of direct and indire
... Show MoreArab translators have always paid great attention to the translation of the Persian literary genres, in particular, contemporary Iranian novels. They have always translated for the most prominent Iranian novelists such as Jalal Al Ahmad, Sadiq Hidayat, Mahmoud Dowlatabadi, Bozorg Alavi, Ismail Fasih, Houshang Golshiri, Gholam-Hossein Saedi, Simin Daneshvar, Sadiq Chubak, Samad Behrangi and others that have succeeded in perfectly picturing the Iranian society.
Within the perspectives of Arab translators and by using the descriptive - analytical approach, the present study provides an analytical study of the translation into Arabic some of the modern Persian novels. Moreove
... Show MoreThe study aims to determine the organizational monitoring mechanism in target organization as well as knowing the suffocation of work. The study depends on a questionnaire as a tool of collecting data on distributed random sample involved (45) person from different levels in manufacturing isphelt Dohuk. The study depends on some hypothesis, the most significant one is that there is not impact of organizational monitoring of suffocation especially on the target organization.
New derivative molecular absorption spectrophotometric methods have been developed for the determination of Al (III) , Mn (II) , individually and binary mixtures . The aim of this model of study is to obtain analytical results characterized by adequate standard of analytical figures of merits through application of derivative Spectrophotometry (dnA/d?n). The two metals acetyl acetonates are chemically stable and are widely used as catalysts . Where Interferences are probable due to very close or nearby peaks or Summits, the Zero – Crossing derivative measurement technique is used to avoid interfering effects between two metals pairs.