In this work a study was made in centrifugal fan blower to investigate the effect of impeller blade design on sound pressure level (SPL). Shroud and unshroud impeller of nine blades are used. The sound generation from flow inside the test rig at different positions was displayed by using spectral analyzer. The experiments were carried out in anechoic chamber with small holes in its walls, under ambient condition about (25-27) C ° to avoid the effect of temperature on the sound pressure level. The results showed that (SPL) decreased with the increase of distance from the source about (3-4)dB when distance varied about (0.8-1.06)m, and the (SPL) decreased with the decrease of velocity about (8-12)dB when velocity varied between (13000-2600) r.p.m., and when the velocity remain constant (SPL) increased with the increased of pressure about (7-15)dB when the pressure varied between (36-8)mbar. For the purpose of comparison, two types of impellers were tested under same conditions, the results showed that (SPL) increased when shroud used on the impeller. The mathematical results show good agreement with the experimental results. The study also concluded a spectral analysis of the noise generated using 1/3 octave band filter. The analysis showed that (SPL) increased with frequency range of (0.8-400) Hz. The maximum sound pressure level was appeared clearly in the frequency range between 200 – 400 Hz .
Praise be to God, Lord of the worlds, and prayers and peace be upon His messenger, the mercy of the worlds.
As for after ....
It is clear from the legal texts in the Noble Qur’an and the Sunnah of the Prophet, that Islam is a method that interferes in everything in beliefs, worship, behavior and transactions, and it forbids excess and extremism and mistrust of people and looking at them through a black lens, self-conceit and contempt of others.
In our research, we will try, God willing, to study the phenomenon of religious extremism with its comprehensive dimensions, the position of Islam on it through the verses and hadiths discussed by it, and the diagnosis of the reasons for its emergence and emergence, because if we learn
The research sheds light on the subject of phraseology as an important field to present metaphysical issues with contemporary scientific discourse. (Primary psychology) It does not apply with the reality of this science and therefore some tried to call it other names such as (Alsai), a unit of measurement of energy activity of things and assets. It was also called metaphysics or metaphysics, but it eventually settled on parapsychology. We try to win Islam and religious concepts with contemporary scientific discourse. The researcher discussed issues that modern science was unable to comprehend and interpreted. He used these subjects to prove the truths of religion and faith. Modern times because the whole universe miracles or as Imam Ghaz
... Show MorePraise be to God, Lord of the Worlds, and prayers and peace be upon our Master Muhammad and upon all his family and companions:
And then: What most concerns rational people and reformers in the modern era is the moral deviation and delinquency that dominates childhood, due to family disintegration and the lack of discipline of most societies according to the religious and moral motives called for by the heavenly messages, especially Islam, which is the final message and guarantees the reform of people in life. Every time and place.
Islam has drawn attention to this issue (childhood) and made it the focus of its consideration, considering that the child is the nucleus of society and the preparation for the future, so it ordered that
Learning education in the Islamic legacy vision considers a completed The Islamic learning education took its bases from origins of Quran and honored prophet Suna , and stressed on education child a good education and providing him with principles of religion and semantic moral values and Messenger (peace on him) considers the higher example for man in his moral, behavior and goodness and witness on this Higher God said
(you had in God Messenger a good leadership for those were requesting God and last day and mentioned God a lot). Al- Ahzab Surah :21. learning education converts man from religion to another and from culture to another and teacher left his signs on the generation if he accept or refuse.
In his novel entitled Victory. Joseph Conrad asserts himself as a writer for man
as a moral agent in this universe. His characters exhibit the possibilities for isolation
and moral deterioration in modern life. The aim of this research is to investigate some
social issues that touch the core of humanity. In this novel, Conrad's perceptive eyes
has noted so many social issues that need to be tackled. Implicitly and explicitly,
Conrad launches so many controversial issues like : communication and
disengagement or skepticism , conflict between heart and mind ,fate, demonic
identification sense of guilt in man, men , women and homosexuality, the clash
between the civilized and the raw ,the disregarded local people and
This research is the subject of "Domination and Motivation in the Sculptures of Mona the Saudi" to the study of an accomplished Arab sculptor with its varied sculptural activity between the works of the exhibition and the works of the squares, as well as its distinguished place among the contemporary Arab sculptors. This research is divided into four chapters:
The first chapter deals with the general methodological framework of the research in terms of the research problem which is focused on the question: What is the hegemony and motivation in the sculptures of Mona Saudi? The importance of research and the need for it, including the technical scientific material concerned with the sculptural achievement of t
... Show MoreThe subject of the tagged research (becoming and integration of the film in postmodern cinema) is summarized by studying the transformations and complementarity of the film in light of the emergence of the concern of postmodernism. Then the need for it, as well as the objectives of the research and clarify its limits, as well as its importance. Then the transition to the theoretical framework, which included two sections, the first topic was entitled: Postmodern Cinema Formation and Completion, while the second topic was entitled: Paradox in Postmodern Film.
After completing the theoretical aspect, the research concluded with a number of theoretical framework indicators that were adopted as a tool for analyzing the sample, then th
... Show MoreIn this paper, method of steganography in Audio is introduced for hiding secret data in audio media file (WAV). Hiding in audio becomes a challenging discipline, since the Human Auditory System is extremely sensitive. The proposed method is to embed the secret text message in frequency domain of audio file. The proposed method contained two stages: the first embedding phase and the second extraction phase. In embedding phase the audio file transformed from time domain to frequency domain using 1-level linear wavelet decomposition technique and only high frequency is used for hiding secreted message. The text message encrypted using Data Encryption Standard (DES) algorithm. Finally; the Least Significant bit (LSB) algorithm used to hide secr
... Show More