The response of the combustor’s liner to the air-flow that passes through it is the key reason for the combustion chambers noise, hence the instabilities of those chambers that decreases the mechanical efficiency of such sections, by increased its mechanical vibrations, which increases the failure rate created during originating of the cracks spreading by the shakes producing by the series of high-level frequencies. Accordingly, any work debating the impact of the context of liners in the combustion chamber can provide grasping for the combustion noise generated by the undesirable vibrations, and benefits the industrial firms to design an ideal production procedure which increases the lifespan of the combustor. The goal of this wo

Background:The technology of nanoparticles has been expanded to many aspects of modern life. Titanium dioxide nanoparticles were of many nanomaterials utilized in biomedical applications. The interactions between nanoparticles and proteins are believed to be the base for the biological effect of the nanoparticles. The oxidation reaction of many substances is catalyzed by oxidizing enzymes called peroxidases. The activity of salivary peroxidase is elevated with periodontal diseases. the aim ofthis study is to examine the action of titanium dioxide nanoparticles on salivary peroxidase activity.Material and method75 participants were enrolled in this study—Periodontitis group with 44 participants and the non-periodontitis group with 31 pa

Lecture method is still need to a part of PBL in order to explain the difficult and abstract concepts in all fields of physics particularly thermodynamics. Introducing and promoting PBL in the lecture method is wise step for innovation in teaching and learning. The objective of this study is to compare the effects of using three methods: problem-based learning (PBL), PBL with lecture method, and conventional teaching on undergraduate physics students’ understanding of thermodynamics. The actual sample size comprises of 122 students, who were selected randomly from the Physics Department, College of Education in Iraq in the academic year 2011-2012. In this study, the pre- and post-test were done and the instruments were administered to the

Soil stabilization with liquid asphalt is considered as a sustainable step towards roadway construction on problematic subgrade soil, there are no requirements to import good quality materials or to implement energy consumption, but to mix the readily available soil with liquid asphalt through the cold mix technique. In this work, collapsible soil obtained from Nasiriya was mixed with asphalt emulsion, lime, and combinations of lime and asphalt emulsion (combined stabilization) and tested in the laboratory for California bearing ratio in dry and soaked conditions. Field trial sections have been prepared with the same combinations and subjected to plate bearing test. The influence of combined stabilization on the structural properties in ter

Nanomaterials have an excellent potential for improving the rheological and tribological properties of lubricating oil. In this study, oleic acid was used to surface-modify nanoparticles to enhance the dispersion and stability of Nanofluid. The surface modification was conducted for inorganic nanoparticles (NPs) TiO₂ and CuO with oleic acid (OA) surfactant, where oleic acid could render the surface of TiO₂-CuO hydrophobic. Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM) were used to characterize the surface modification of NPs. The main objective of this study was to investigate the influence of adding modified TiO₂-CuO NPs with weight ratio 1:1 on thermal-physical propertie

 This research was to determine the effect of rare earth metal (REM) on the as-cast microstructure of Mg-4Al alloy. The rare earth metal used here is Lanthanum to produce Mg-4Al-1.5La alloy. The microstructure was characterized by optical microscopy. The phases of this alloy were identified by X-ray diffraction. The microstructure of Mg-4Al consists of α-Mg and grain boundaries with precipitated phase particles. With the addition of Lanthanum, three distinct phases were identified in the X-ray diffraction patterns of the as cast Mg-4Al-1.5La:  Mg, Al₁₁La₃, Al₄La. The Mg₁₇Al₁₂ phase was not detected. The addition of Lanthanium increases the hardness and dec

In this study, the effect of construction joints on the performance of reinforced concrete beams was experimentally investigated. Seven beam specimens, with dimensions of 200×100×1000 mm, were fabricated. The variables were considered including; the location and configuration of the joints. One beam was cast without a joint (Reference specimen), two specimens were fabricated with a one horizontal joint located either at tension, or compression zone. The fourth
beam had two horizontal joints placed at tension, and compression area. The remaining specimens were with one or two inclined joints positioned at the shear span or beam’s mid-span. The specimens were subjected to a monotonic central concentrated loading until the failure. T