In this paper, variable gain nonlinear PD and PI fuzzy logic controllers are designed and the effect of the variable gain characteristic of these controllers is analyzed to show its contribution in enhancing the performance of the closed loop system over a conventional linear PID controller. Simulation results and time domain performance characteristics show how these fuzzy controllers outperform the conventional PID controller when used to control a nonlinear plant and a plant that has time delay.
In this paper, an analytical solution describing the deflection of a cracked beam repaired with piezoelectric patch is introduced. The solution is derived using perturbation method. A novel analytical model to calculate the proper dimensions of piezoelectric patches used to repair cracked beams is also introduced. This model shows that the thickness of the piezoelectric patch depends mainly on the thickness of the cracked beam, the electro-mechanical properties of the patch material, the applied load and the crack location. Furthermore, the model shows that the length of the piezoelectric patches depends on the thickness of the patch as well as it depends on the length of the cracked beam and the crack depth. The additio
... Show MoreThe ionospheric characteristics exhibit significant variations with the solar cycle, geomagnetic conditions, seasons, latitudes and even local time. Representation of this research focused on global distribution of electron (Te) and ion temperatures (Ti) during great and severe geomagnetic storms (GMS), their daily and seasonally variation for years (2001-2013), variations of electron and ion temperature during GMS with plasma velocity and geographic latitudes. Finally comparison between observed and predicted Te and Ti get from IRI model during the two kinds of storm selected. Data from satellite Defense Meteorological Satellite Program (DMSP) 850 km altitude are taken for Te, Ti and plasma velocity for different latitudes during great
... Show MoreIn this paper, the effect of thermal radiation and magnetic field on the boundary layer flow and heat transfer of a viscous fluid due to an exponentially stretching sheet is proposed. The governing boundary layer equations are reduced to a system of ordinary differential equations. The homotopy analysis method (HAM) is employed to solve the velocity and temperature equations.
In this paper, a robust adaptive sliding mode controller is designed for a mobile platform trajectory tracking. The mobile platform is an example of a nonholonomic mechanical system. The presence of holonomic constraints reduces the number of degree of freedom that represents the system model, while the nonholonomic constraints reduce the differentiable degree of freedom. The mathematical model was derived here for the mobile platform, considering the existence of one holonomic and two nonholonomic constraints imposed on system dynamics. The partial feedback linearization method was used to get the input-output relation, where the output is the error functions between the position of a certain point on the platform
... Show Moresolation of candida spp. From cancer patients who suffered oral candidiasis due to immunodeficiency
Background: the most common cause of obstructive jaundice is CBD stones, and these can produce significant morbidity and mortality. The management of the obstructive jaundice due to CBD stones is in evolution; several methods of investigations and treatment have been introduced, and each one has its own advantages and disadvantages.
Objective: to study and evaluate the management of obstructive jaundice due to CBD stones in Baghdad teaching hospital.
Results: from the 125 patients presented with obstructive jaundice included in this study 14 patients were found to have a periampullary lesions, and they were excluded from the study, so the total number of the patients was
... Show MoreIn this research, the concentration of radon gas has been calculated in the classrooms of schools in Diyala Governorate by using the nuclear track detector (CR-39), which was one of the organic solid-state nuclear detectors (SSNTDs). After calculating the radon gas concentration, the lung cancer cases were calculated. The results showed that the lowest value was found in (Alshumue) school (4.753) people. In contrast, the highest value was found in (Habhib) school (20.421). The average values of lung cancer cases in Diyala governorate were equal to (9.319) per person. The results showed that the number of lung cancer cases per year per million persons in Diyala Governorate schools was below the allowed limit from (ICRP) agency (170-230) p
... Show MoreIn this paper, we introduce and study the essential and closed fuzzy submodules of a fuzzy module X as a generalization of the notions of essential and closed submodules. We prove many basic properties of both concepts.
Background: Seasonal variation and gender preponderance have not been adequately studied in Guillain-Barre syndrome (GBS).
Objective: This study aims to evaluate the seasonal variation and sex preponderance in children with Guillian Barré Syndrome.
Patients and methods: A cross sectional study was carried out by reviewing wards’ registry of all cases with Guillian Barré Syndrome admitted to Children Welfare Teaching Hospital during a 10-year period (1999 - 2008). Age, sex, seasonal distribution, residence and outcome were analysed.
Results: Guillian Barré Syndrome was diagnosed in 217 (126 boys, 91 girls) patients and the annual hospital rate of admission was 22.9 /100000 children. There was increase annual incidence from 1