Recently, environmental noise has arisen from various sources, such as those from exhaust mufflers of combustion engines found in cars, trucks, or power generators, which produce significant noise during their operation. Controlling the radiated noise from these mufflers is a major factor in improving acoustic comfort and minimizing the impact on the surrounding communities. Numerous research has been presented for this reason by modification of the internal structure of the exhaust muffler. The main objective of this work is to reduce the noise level emitted from exhaust mufflers. This can be achieved by adjusting structure parameters to attenuate the surrounding environment's radiated noise. Analysis of pressure-wave propagation has been done by building 3D models using COMSOL Multiphysics software. Different entities were conducted to investigate the influence of muffler shells and plate thicknesses on acoustic performance through the frequency domain to obtain better attenuation. SPL over a frequency band is presented, describing how the sound intensity varies at different frequencies within a given bandwidth. The results showed that increasing the muffler shell thickness improved the TL; this particularly causes a double value at a range above 1.2 kHz, where there are two distinct peaks at 1.3 kHz and 2.8 kHz. Additionally, it was found that increasing the muffler plate thickness reduces the TL whole range and moves the curve peak to higher frequencies. This is because the pressure pulses that stimulate the shell plates would exert a more distinct influence on plates characterized by a reduced thickness, and the muffler structure thickness is correlated with its increased stiffness, resulting in an elevation of the frequency for this eigenmode
The present paper sheds light on the psychological structure of Simha Bin Zion’s A Broken Soul. After reviewing the biography of the storyteller, it is clear that the hero of the rebellious character in the story of (A Broken Soul) is the writer himself. The storyteller directly begins to depict his psychological sufferings in his childhood days. He tells a story full of sadness and refusal of the neglect he suffered in his childhood. It is obvious that the early five years of Samha bin Zion’s life is considered a period of conflict that participated in the formation of his individual identity. The story represents an outlet for a hidden secret world buried under the layers of his consciousness. It deals with
... Show MoreCervical carcinoma represent the second predominant cancer in female and there is a strong correlation between cervical cancer and the infection with high-risk types of HPV and expression the viral oncogenes. EMT is viewed as a vital advance in carcinoma development and ensuing metastasis. To evaluate correlation between the expression of Twist and HPV16 infection in a group of Iraqi patients with cervical carcinoma. A total of forty paraffin blocks included in this study which were divided into 30 sample of cervical cancer infected with HPV16and 10 sample of normal cervical tissues. The samples were subjected to immunohistochemical technique using Anti-Twist2 polyclonal antibody. The obtained data from this study indicate that majority of
... Show MoreLuqman's story stated that human instinct, if I was brought up properly, reaches wisdom and inflicts the right to everything. It is to go to worship God and adhere to the satisfaction of morals and high morals that are ordered to meet among human beings in this life, because this worship educates in the soul the most beautiful morals needed by human beings of honesty, honesty and modesty, and the work of good and virtues, and distancing the soul from evil and vices.
The military presence in the Gulf region after the British withdrawal from it in 1971 was one of the most important pillars of the American strategy to climb the ladder of global leadership, as the geostrategic features that the region enjoyed provided factors of controlling energy sources and global trade routes. The United States of America guarantees Western Europe and Japan the process of access to energy sources and the exclusion of its opponents from the region, especially the Soviet Union, and the growing American military presence in the Gulf after the invasion of Iraq in 2003. On the other hand, the region experiences many contradictions, some of which threaten its security, such as the exacerbation of disputes between its count
... Show MoreOne of the most important problems in tablet process is to control the flow of the catalyst through the hopper; Controlling the flow can be done either by changing the size of particles or added the different lubricant (stearic acid, starch, graphite) or blending of different lubricants. The study showed that we can control (increase or decrease) on the flow of the catalyst through the hopper by blending different lubricants for the constant percentage. The flow increasing when particles size (0.6 mm) and then decrease with or without lubricants, no effect on flow when particles size lower than (0.2 mm) with use that lubricants, and good flow on (0.4 mm) when use stearic acid and starch.
This research aims to create lightweight concrete mixtures containing waste from local sources, such as expanded polystyrene (EPS) beads and waste plastic fibers (WPFs), all are cheap or free in the Republic of Iraq and without charge. The modern, rigid, and mechanical properties of LWC were investigated, and the results were evaluated. Three mixtures were made, each with different proportions of plastic fibers (0.4%, 0.8%, 1.2%), in addition to a lightweight concrete mixture containing steak fibers (0.4%, 0.8%, 1.2%), in addition to a lightweight concrete mixture. It contains 20% EPS. The study found that the LWC caused by the addition of WPFs reduced the density (lightweight) of the concrete mixtures because EPS tends
... Show MoreBirds of prey (Raptors) are top predator avian species that many migrate annually through Mesopotamian marshes in southern Iraq toward their wintering grounds in Arabia and Africa, while others are breeding residents; however, information on their current status is scarce. From January 2016 to April 2019, a total of 20 field expeditions were conducted in the geographical zone of the Mesopotamian marshes, wetlands of international importance. The survey covered the Central Marshes, Al-Hammar and Hawizeh Marsh. One of the objectives of the field surveys is to list the raptors species that wintering and/or migrating through the Mesopotamian marshes and to understand their current spatial and temporal distribution. In the present study, a to
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The current research aims to testing the impact of leadership styles (autocratic, democratic) in crises management (Making decision response, communications and information flows, Mobilization of resources) through strategic planning (Mission, objectives, and environmental analysis, and strategic choice) among managers of the Iraqi Ministry of electricity. Questionnaire has been adopted as a tool in data and information relating to research, as it had prepared on the basis of number of scales and finished using the included Likert quintet, which has been subjected to standards of validity and reliability and distributed to a sample consisting of (96) managers at the three departments of Min
... Show MoreMost studies on deep beams have been made with reinforced concrete deep beams, only a few studies investigate the response of prestressed deep beams, while, to the best of our knowledge, there is not a study that investigates the response of full scale (T-section) prestressed deep beams with large web openings. An experimental and numerical study was conducted in order to investigate the shear strength of ordinary reinforced and partially prestressed full scale (T-section) deep beams that contain large web openings in order to investigate the prestressing existence effects on the deep beam responses and to better understand the effects of prestressing locations and opening depth to beam depth ratio on the deep beam performance and b
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