Journal of University of Babylon

The paper gives an experimental study on the performance on the wind turbine rotors with several ‎numbers of blades as well as twist angle. The main goal of this study is to demonstrate the effect ‎blades number, tip angles as well as the twist angle of the blades on the power coefficient (Cp) of the ‎rotor. Moreover, this result represents a simple evaluation about the range of depending power ‎coefficient on the average wind speed.‎
Also, this paper studies the performance of wind turbines which are tested by carrying out 2-‎dimensional dynamic using ANSYS-Fluent.‎

‎ The paper deals with a creep behavior of Pb – Sn eutectic alloy is studied. The creep ‎experiments were executed at constant tensile stress (4.2, 5.5 and 6.5 MPa) in range of temperature ‎‎360 – 430K. From traditional analysis of steady – state creep is acquired the creep data. The curves ‎creep are showed temperature effect, the stress sensitive variable, and evident activation energy of ‎creep. The evident activation energy and stress exponent for creep were delimited as approximately ‎‎57 KJ/mole and 4 respectively. The values of n and Q are delicate to the process controlling creep ‎deformation. Optical microscope was used to test the microstructure of samples before and after ‎creep deformation to find the mechanisms of creep deformation. The strain of Pb-61.7wt%Sn is ‎increased during creep test and according to subjected stress value. The best value of strain at 360K ‎and in stress 6.5MPa about 0.3, also can be get little strain values at (360, 370,380,390K) and at ‎‎4.2MPa are (0.1,0.15, 0.2, 0.3) respectively.‎

To ensure the best operations situation of the wind turbine under critical conditions, a thoroughly analysis of ‎converter controls in both machine and grid sides is essential. The grid side is playing the major role therefore its ‎codes as stabilization, fault ride through, quality of power improving, synchronizing, controlling power and other ‎codes must be satisfied. This paper aims to analyze the Doubly-Fed Induction Generator (DFIG). Analysis shall ‎cover the situations: under balanced grid, under voltage sag, under voltage swell, under changes in reactive power ‎demand and under changes in supply frequency. The system model and controlling are needed to analyze the ‎whole DFIG system in the steady-state and transient state operations. A back to back converters are used in this ‎system. A model of the grid converter independently controlling the active and reactive power including dc-link ‎voltage is constructed. Machine side converter model is also built such that it is maintaining the unity power-factor ‎and controlling reactive power regardless the transient condition of the grid. MATLAB/SIMULING models are used ‎for this analysis.‎

There is an impact of population growth on urban land uses, and it is necessary to prepare ‎and predict the possible or potential results, and the problems it causes as a result of poor ‎planning, management and implementation, not to mention the negligence in calculating the ‎direction and size of the relationship between population growth and urban growth, in particular ‎urban saturation and diversity. The potential effect of population growth, and in order not to ‎wait for the problem to occur, we must take the initiative and recognize that there is a local and ‎regional problem in the issue of housing and population growth, meaning that the housing stock ‎does not meet the housing need due to the increasing population growth, which creates an ‎increasing gap between them. The research adopted a descriptive analytical approach to real ‎historical data for both residents and residential areas and the sustainable standard share of ‎residential use for Najaf district. Which was divided into six zones to make it easier for us to ‎study them, analyze their variables, and predict the growing sustainable standard of residential ‎areas for the next five years in the study area. One of the most important results is that there is a ‎mismanagement and wrong estimation of population growth that has generated urban saturation ‎in urban land uses. Foremost among them is the varying impact of population growth on the ‎sustainable housing standard, which, of course, has created a decent and acceptable sustainable ‎standard ratio for residential use and another that is unsustainable, inappropriate and ‎unacceptable for residential use, both of them are located between the upper and lower limits of ‎the standard and sometimes out of standards. In order to maintain the sustainability of the ‎growing standard to conform the reality of urban land uses, it is necessary to move or relocate the ‎developing population within or outside zone to create sustainable harmony between population ‎and housing under a growing and sustainable standard. ‎

The development that took part by the early twentieth century in the field of civil ‎engineering, especially concrete construction, was accompanied by extensive progress in the ‎implementation of high-rise building units.‎
Slipform system is the latest executive method that offers the property of greatly reducing ‎construction time compared to other methods by adopting automatic sliding of the total slipform ‎and‏ ‏enabling continuous work 24 hours.‎
The purpose of this research is to achieve the proactive, organizational and preventive ‎procedures (within scientific and applied frameworks) to implement reinforced concrete structures ‎using the slipform system which insures the possibility and high ability to carry out the work ‎properly.‎
The safe standards in the slipform system are applied through the method of installation of ‎the slipform, pre-work test procedures, the homogeneity of the distribution of the used loads, ‎continuous checking and monitoring of the slipform movement during operation and maintaining ‎its balance, in addition, the appropriate method for using casting concrete and preliminary tests of ‎concrete retarder additives, maintaining the concrete cover during pouring and the movement of ‎the slipform and avoiding concrete sticking to the slipform are considered. These important steps ‎and proper procedures in the implementation work are guarantee of the success of the work.‎

The capacity of eco-friendly biosorbents low cost a biosorbent for methylene blue dye ‎‎(MBD) removal from wastewater is investigated in this work. In order to assess the potential ‎treatment of industrial aqueous solutions by Activated Carbon, Palm leaf and Pomegranate peel, a ‎series of laboratory batch flow experiments were conducted . Batch studies were carried out to ‎investigate the effects of pH dye solution, contact time, biosorbent dosage, beginning dye ‎concentration, and rotational speed on MBD biosorption at room temperature. The optimal ‎parameters for MBD removal by Activated Carbon, Palm leaf, and Pomegranate peel were ‎determined to be pH 5 and 1 g/100 ml dye solution, 120 min contact time for MBD concentration ‎of 100 mg/l, and agitation speed of 250 rpm. The experimental data were analyzed using Langmuir ‎and Freundlich isotherm models. The Langmuir biosorption isotherm was found to be the best ‎model for simulation of MBD bisorption into Activated Carbon, Palm leaf and Pomegranate peel , ‎with the Langmuir constant linked to the biosorption ability (qmax) of 7.87, 2.78 and 2.33 mg/g and ‎a coefficient of determination (R2) of 0.9996, 0.9985 and 0.9999 for Activated Carbon, Palm leaf ‎and Pomegranate pee. The results indicate that activated carbon is the best environmentally friendly ‎bio-adsorbent used in this study, which can be used efficiently to remove methylene blue dye from ‎aqueous solutions.‎