Abstract

    Corrosion-fatigue occurs by the combined actions of cyclic loading and corrosive environment. The effect of shot peening on cumulative corrosion-fatigue life of 1100-H12 Al alloy was investigated. Before fatigue testing, specimens were submerged in 3.5%NaCl solution for 71 days. Constant fatigue tests were performed with and without corrosive environment. Cumulative corrosion-fatigue tests were also carried out in order to determine the fatigue life before and after shot peening. The constant fatigue life was significantly reduced due to corrosive environment and the endurance fatigue limit was reduced by 13% compared with dry fatigue. In case of shot peening the cumul

In this paper, a computational method for solving optimal problem is presented, using indirect method (spectral methodtechnique) which is based on Boubaker polynomial. By this method the state and the adjoint variables are approximated by Boubaker polynomial with unknown coefficients, thus an optimal control problem is transformed to algebraic equations which can be solved easily, and then the numerical value of the performance index is obtained. Also the operational matrices of differentiation and integration have been deduced for the same polynomial to help solving the problems easier. A numerical example was given to show the applicability and efficiency of the method. Some characteristics of this polynomial which can be used for solvin

In this paper the variable structure control theory is utilized to derive a discontinuous controller to the magnetic levitation system. The magnetic levitation system model is considered uncertain, which subjected to the uncertainty in system parameters, also it is open-loop unstable and strongly nonlinear. The proposed variable structure control to magnetic levitation system is proved, and the area of attraction is determined. Additionally, the chattering, which induced due to the discontinuity in control law, is attenuated by using a non-smooth approximate. With this approximation the resulted controller is a continuous variable structure controller with a determined steady state error according to the selected control

     The aim of this research is to study the surface alteration characteristics and surface morphology of the superhydrophobic/hydrophobic nanocomposite coatings prepared by an electrospinning method to coat various materials such as glass and metal. This is considered as a low cost method of fabrication for polymer solutions of Polystyrene (PS), Polymethylmethacrylate (PMMA) and Silicone Rubber (RTV). Si were prepared in various wt% of composition for each solutions. Contact angle measurement, surface tension, viscosity, roughness tests were calculated for all specimens. SEM showed the morphology of the surfaces after coated. PS and PMMA showed superhydrophobic properties for metal substrate, while Si showed hydroph

Food comes after air and water in terms of importance in the survival of human beings, In addition, it is the support and strength of health and support, if lost or destroyed man would die or get sick and become a heavy burden on himself and his society. Food, like other sources of life, is subject to various risks and corruption comes from countless sources. Among these dangers is the result of spontaneousness, lack of knowledge or compulsion due to the interaction of variables beyond the will of the producer and the consumer, such as pollution of water, air and environment and their reflection on food consumed by people. However, we can’t deny that some reasons of corruption are intentional and resulting from a planning in advance in

The paper is concerned with a linguistic analysis of  the blurbs, used in advertising English and Arabic novels.  A blurb is an advertising persuasive text, written on the back cover of a book. Blurbs of selected novels are chosen as  representative examples. The selected blurbs belong to two languages, Arabic and English. The paper aims at studying the linguistic features that are characteristic of blurbs as advertising texts and making a sort of comparison between English blurbs and Arabic ones. A linguistic analysis on four levels is presented. Blurbs are tackled from the point of view of four linguistic disciplines that are phonology, syntax, semantics and discourse analysis. A reference is made to the linguistic featu

This study calculated the surface roughness length (Z_o), zero-displacement length (Z_d) and height of the roughness elements (Z_H) using GIS applications. The practical benefit of this study is to classify the development of Baghdad, choose the appropriate places for installing wind turbines, improve urban planning, find rates of turbulence, pollution and others. The surface roughness length (Z_o) of Baghdad city was estimated based on the data of the wind speed obtained from an automatic weather station installed at Al-Mustansiriyah University, the data of the satellite images digital elevation model (DEM), and the digital surface model (DSM), utilizing Remote Sensing Techniques. The study area w

Linking adverbials are used to organize and bridge together extended stretches of discourse to make the text coherent. They are explicit indicators of the communicative function of the sentence and writers use them to let their readers follow what has already been said and to help them anticipate what is about to follow.
Linking adverbials include those relations of addition, enumeration, summation, apposition and so on. Through the use of these adverbials, the writer is able to organize and develop his ideas and help the reader follow him from one sentence to another. Thus, a linking adverbial is a semantic relation used to show the way in which what is to follow is systematically connected to what has gone before. So, they have anap

In the present work, the focusing was on the study of the x-ray diffraction, dielectric constant, loses dielectric coefficient, tangent angle, alter- natively conductivity and morphology of PET/BaTio3. The PET/BaTio3 composite was prepared for polyethylene terephthalate PET polymer composite containing 0, 10, 20, 30, 40, 50, and 60 wt. % from Barium titanate BaTi03 powder. The composite of two materials leads to form mixing solution and hot-pressing method. The effect of BaTio3 on the structure and dielectric properties with morphology was studied on PET matrix polymer using XRD, LCR meter and SEM.