Fatigue failure is almost considered as the predominant problem affecting automotive parts under dynamic loading condition. Thus, more understanding of crack behavior during fatigue can strongly help in finding the proper mechanism to avoid the final fracture and extent the service life of components. The main goal of this paper is to study the fracture behavior of low carbon steel which is used mostly in automotive industry. For this purpose, the fractography of samples subjected to high and low stress levels in fatigue test then was evaluated and analyzed. Hardness and tensile tests were carried out to determine the properties of used steel. Also, the samples were characterized by microstructure test and XRD analysis to examine the constitute phases. The fatigue test (S-N curve) was done at stress ratio (R= -1), and the fracture examination was perform using Scanning Electron Microscope (SEM). The results of microstructure and XRD analysis were indicating that the Ferrite and a little amount of pearlite are the dominant phases of this steel. Whereas, the fractography observations reveal that the void coalescence ductile fracture is the main failure mode in samples with high stress level, while the ductile fracture (void coalescence) with Transgranular Cleavage fracture was noticed in low stress fatigue mode for this alloy.
يحتل افلاطون (427-327 ق.م) المكانة الاولى بين الفلاسفة والمفكرين والمربين على امتداد تاريخ البشرية ، ويعد بعض الباحثين كتابه الشهير(الجمهورية) كتاباً في التربية والتعليم قبل ان يكون كتاباً في الاخلاق والسياسة ، فهذا الكتاب – المحاورة ضم بين دفتيه أجوبة على الكثير من الاسئلة التربوية والتعليمية عوضاً عن مضامينه الاخلاقية والسياسية والمعرفية والنفسية ، التي ساقها افلاطون باسلوب ادبي متين على شكل محاورة طو
... Show MoreRiding in Andalusia was a sport emphasized by Islam. It also works to strengthen the muscles, prevent them from sagging, gain vitality and vitality, regulate blood circulation and improve brain and heart function. The research we discussed in the study is not limited to a particular class. Most Andalusian rulers practiced equestrian And they hold concerts and competitions of horse competition, as happened during the reign of Caliph al-Hakam al-Mustansir and Muzaffar ibn Abi Amer and the governor adopted Ben Abbad and the Caliph Muhammad bin Bani al-Ahmar, the governor of the city of Granada in the presence of the great poets such as the son of Abu Salt and Ibn
... Show Moreلطالما تحاشينا الخوض في الحديث عن المرأة , وكل ما يتعلق بها من موضوعات , خصوصا في سياق ما يطرح حولها من أمور كأنها لاتخص غيرها مثل : " الحرية " "والمساواة " " والحقوق " ... وغيرها من المواضيع التي تعج بها الكتب والشاشات والبرامج والمؤتمرات والندوات , التي غالبا ما ترفع فيها الشعارات المؤدلجة وتوضع اخرى , في أتون محموم , إن دل على شيئ فانه يدل بالدرجة الاولى عن مدى الفوضى الفكرية التي نعي
... Show MoreBackground: The purpose of this study is to investigate the relationship between the roots of the maxillary posterior teeth and the maxillary sinus using spiral computed tomography, and measured the distances between the roots of the maxillary posterior teeth and the sinus floor. Materials and Methods: The sample of the present study was a total of 120 Iraqi subject (60 males & 60 females) aged (20-60) years old, who admitted to spiral Computed Tomography scan unit in AL-Zahraa hospital in AL-Kut city to have Computed Tomography scan of the brain and paranasal sinuses who had complaints of headaches or with suspicion of sinusitis but without pathological findings in maxillary sinuses. From November 2012 to April 2013, CT sagittal reconstruc
... Show MoreDeveloping and researching antenna designs are analogous to excavating in an undiscovered mine. This paper proposes a multi-band antenna with a new hexagonal ring shape, theoretically designed, developed, and analyzed using a CST before being manufactured. The antenna has undergone six changes to provide the best performance. The results of the surface current distribution and the electric field distribution on the surface of the hexagonal patch were theoretically analyzed and studied. The sequential approach taken to determine the most effective design is logical, and prevents deviation from the work direction. After comparing the six theoretical results, the fifth model proved to be the best for making a prototype. Measured results rep
... Show MoreA new ligand [N-(4-methoxy benzoyl amino)-thioxo methyl ] leucine (MBL) was prepared from the reaction of (4-methoxy benzoyl isothiocyanate with leucine acid in molar ratio (l:l), it was characterized by elemental analysis (C.H.N.S), FT-IR, UV-Vis, 1H and 13C-NMR. The complexes of the bivalent ions (Mn, Fe, Co, Ni, Cu, Zn, Cd and Hg ) have been prepared and characterized too. The structural was established by elemental analysis (C.H.N.S), FT-IR, UV-Vis spectra, conductivity measurements atomic absorption and magnetic susceptibility and determination of molar ration (M:L). The complexes showed characteristic behavior of tetrahedral geometry around the metal ions except with (Cu) complex showed square planer.
This paper presents the implementation of a complex fractional order proportional integral derivative (CPID) and a real fractional order PID (RPID) controllers. The analysis and design of both controllers were carried out in a previous work done by the author, where the design specifications were classified into easy (case 1) and hard (case 2) design specifications. The main contribution of this paper is combining CRONE approximation and linear phase CRONE approximation to implement the CPID controller. The designed controllers-RPID and CPID-are implemented to control flowing water with low pressure circuit, which is a first order plus dead time system. Simulation results demonstrate that while the implemented RPID controller fails to stabi
... Show MoreThe paper is concerned with the state and proof of the existence theorem of a unique solution (state vector) of couple nonlinear hyperbolic equations (CNLHEQS) via the Galerkin method (GM) with the Aubin theorem. When the continuous classical boundary control vector (CCBCV) is known, the theorem of existence a CCBOCV with equality and inequality state vector constraints (EIESVC) is stated and proved, the existence theorem of a unique solution of the adjoint couple equations (ADCEQS) associated with the state equations is studied. The Frcéhet derivative derivation of the "Hamiltonian" is obtained. Finally the necessary theorem (necessary conditions "NCs") and the sufficient theorem (sufficient conditions" SCs") for optimality of the stat
... Show MoreReal Time Extended (RTX) technology works to take advantage of real-time data comes from the global network of tracking stations together with inventor locating and compression algorithms to calculate and relaying the orbit of satellite, satellite atomic clock, and any other systems corrections to the receivers, which lead to real-time correction with high accuracy. These corrections will be transferred to the receiver antenna by satellite (where coverage is available) and by IP (Internet Protocol) for the rest of world to provide the accurate location on the screen of smartphone or tablet by using specific software. The purpose of this study was to assess the accuracy of Global Navig