Articles in This Issue
Abstract
In this work, a Fuzzy Model Reference Adaptive Controller FMRAC is presented for the speed control problem of a DC motor. The proposed controller is designed in two phases. In the first phase, the model reference input-output data is used to obtain the fuzzy rules. Then the effective rules are chosen to be used in the second phase. In the second phase, the obtained controller is applied in two conditions; the non fuzzy rules or adjusting the center of output membership functions. The simulation results shows a good speed motor tracking to the model reference in the word of the step response coefficients.
Abstract
Particle Swarm Optimization Algorithm (PSOA) has emerged recently as an efficient and powerful technique for the optimization of real parameters. The current study presents control scheme for electro-hydraulic actuator system which utilizes particle swarm optimization (PSO) for off-line tuning of the Fuzzy Proportional-Derivative (Fuzzy PD) controller. The gains and Membership Functions (MFs) tuned by PSOA which has been implemented depending on the performance indices: ITAE (Integral Time of Absolute Error), ISE (Integral Square of Error), and IAE (Integral Absolute of Error).
Abstract
In this paper the artificial neural network used to predict dilly evaporation. The model was trained in MATLAB with five inputs. The inputs are Min. Temperature, Max. Temperature, average temperature, wind speed and humidity. The data collected from Alramadi meteorological station for one year. The transfer function models are sigmoid and tangent sigmoid in hidden and output layer, it is the most commonly used nonlinear activation function. The best numbers of neurons used in this paper was three nodes. The results concludes, that the artificial neural network is a good technique for predicting daily evaporation, the empirical equation can be used to compute daily evaporation (Eq.6) with regression more than 96% for all (training, validation and testing) as well as, in this model that the Max. Temperature is a most influence factor in evaporation with importance ratio equal to (30%) then humidity (26%).
Abstract
The White Cement Kiln Dust (WCKD) is a byproduct material, formed in cement factory during the operation of cement production. In highway construction, the WCKD can be used in different ways such as stabilizing the subgrade of highway embankment and as mineral filler in Hot Mix Asphalt (HMA); the latter usage will give clean and healthy environment in addition to more economy. In Iraq, there are two common types of fillers, Portland cement and lime stone powder. In this research, WCKD taken from Fallujah cement plant used as mineral filler in addition to two common types. Various percentages , such as 100%WCKD, 50%WCKD + 50%Cement(C) ,100%C , 50%WCKD+50%Limestone (L), and 100% L, were used to prepare asphaltic concrete mixes. In general, five tests were used to evaluate the performance of these mixes. Standard Marshall Test procedure was applied under three different conditions, two of them at two temperatures at 60 OC and 70 OC and in the third one it was used to test samples immersed in water, at room temperature(24 OC), for four days. Indirect Tensile Strength Test (ITST) was used to evaluate conditioning and un-conditioning samples. All test results, when compared with controlled asphalt concrete sample (Sample contained 100% limestone as filler), were acceptable and within the AASHTO and Iraqi Standard Specifications of Roads & Bridges 2003. Stability values, at standard condition test, of samples containing 100% WCKD, 50%WCKD+50%C, and 50%WCKD+50%L are 11.9kN, 13.2kN, and 14.0kN respectively, while for controlled sample was 9.0kN. The Marshall stiffness values showed similar trends, for samples having 100% WCKD, 50%WCKD+50%C, and 50%WCKD+50%L giving 3.22kN/mm, 3.38kN/mm, 3.5kN/mm respectively but for controlled sample was 2.43 kN/mm. Same trends of results gained in ITST .The results showed the beneficial using of WCKD as filler that will conserve the environment and encourage the HMA producers to use this inexpensive material in their works.
Abstract
Laminar natural convection heat transfer and fluid flow due to the heating from below at variable heat source length inside two dimensional enclosure has been analyzed numerically in this study. The enclosure has filled with air as a working fluid. The vertical inclined walls of the enclosure are maintained at lower temperature while the remaining walls are insulated. The value of Rayleigh number from (1x103 ≤ Ra ≤ 4x104), the inclination angle at (γ = 0o, 22.5o , 45o ) and dimensionless heat source length at ( S = 1 and 0.5 ). The continuity, momentum and energy equations have been applied to the enclosure and solved by using finite difference method. The results showing that the average Nusselt number increases with the increasing of the heating source length and decreases with the increasing in an inclination angle of the vertical walls.
Abstract
This paper presents the experimental results of composite slabs under static and impact loading. Total of six specimens classified one specimen test under static loading and the remaining five were tests under impact dynamic loading with different parameters as type of connections and degree of interaction of composite slab. Low - velocity impact test was adopted by select the falling mass (4 kg) made from steel material and formed as ball shape without nose. The ball dropped freely from height of (2.4 m) and strikes the top of composite slab. The designed dimensions of specimens is (500×500×60 mm) as reinforced concrete slab that reinforced by mesh of (RBC) and the steel plate is (3 mm) in thickness. Deflection due to first crack is recorded, number of blows caused first crack and failure were counted. The test results showed that the welded stud connectors gives high strength capacity and resistance under static and impact dynamic loadings than other than type of connections, also, full interaction as degree of interaction is better than others
Abstract
The Organo modified and unmodified sodium montmorillonite clay effect on thermal and mechanical properties of the waste low density polyethylene (wLDPE) were studied. Commercialize unmodified (MMT) and Organo-modified clay (OMMT) were added to the wLDPE to prepare wLDPE-clay noncomposites by melt intercalation method. OMMT and MMT were added in a range of 1-5 wt %. Fourier transform infrared spectroscopy (FTIR) used to evaluate polymer structure before and after the fabrication. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to analyse the thermal stability and thermal properties for the wLDPE and fabricated nanocomposites. Tensile mechanical characteristics of the waste specimens before and after nanocompsite fabrication were evaluated. The FTIR exhibited no change in the chemical structure of the wLDPE used after clay addition. Melting temperature and crystallization percentage were increased up to 1 wt% loaded and decreased in with clay content increasing when compared to the original waste matrix. The thermal steadiness of the wLDPE /clay nanocomposites were found enhanced in the case of loading 3 wt% of OMMT. The elastic modulus has improved in the 3% OMMT loaded.
Abstract
A sample of 50 randomly selected rural and urban roads of Ramadi district were observed for asphalt pavement Distresses. Three main types of Distresses were considered; rutting, cracks and pavement separation. In addition, different other Distresses types that were observed were grouped in one category named "Other". For each road, information about the age of the pavement was recorded. Kaplan-Meier method was carried out in order to understand the Remain time before pavement deterioration as well as to compare pavement service life with respect to the type of Distress. Results of this research revealed significant differences between pavement service life corresponding to the type of Distress. Pavement service life appeared to last less than 20 months when all the mentioned types of Distresses are occurred on the road