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 .
This paper deals with an analytical study of the flow of an incompressible generalized Burgers’ fluid (GBF) in an annular pipe. We discussed in this problem the flow induced by an impulsive pressure gradient and compare the results with flow due to a constant pressure gradient. Analytic solutions for velocity is earned by using discrete Laplace transform (DLT) of the sequential fractional derivatives (FD) and finite Hankel transform (FHT). The influences of different parameters are analyzed on a velocity distribution characteristics and a comparison between two cases is also presented, and discussed in details. Eventually, the figures are plotted to exhibit these effects.
Galvanic corrosion of stainless steel 316 (SS316) and carbon steel (CS) coupled in 5% wt/v sulfuric acid solution at agitation velocity was investigated. The galvanic behavior of coupled metals was also studied using zero resistance ammeter (ZRA) method. The effects of agitation velocity, temperature, and time on galvanic corrosion current and loss in weight of both metals in both free corrosion and galvanic corrosion were investigated. The trends of open circuit potential (OCP) of each metal and galvanic potential (Eg) of the couple were, also, determined. Results showed that SS316 was cathodic relative to CS in galvanic couple and its OCP was much more positive than that of CS for all investigated ranges of
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This research’s goal is to restore and to revive the jurisprudence of Mother of Believers (Um alMuaamineen) “Um Salmah” "may God bless her", and to highlight her outstanding assimilation and understanding of religion and her conscious thought. The current research is a comparative scientific theoretical study represented in the comparison of jurisprudence of “Um Salamah” with Hadiths of fasting and pilgrimage rules as well as the duration mentioned in jurisprudence of for doctrines( 4 schools of thought )to identify these hadiths with the inclusion and discussion of their evidence.
The current research included two topics: the first one is to identify and introduce
... Show MoreThe aim of this study is to identify the effect of enabling the effectiveness of the work of the audit committees in private commercial banks and to identify the extent of awareness of the importance of empowerment in the work of these committees, especially as it is known that these committees, especially the inspection committees that go to private banks and from various sources including committees of the Central Bank of Iraq Committees of the Securities Commission and finally committees of the external audit offices, through an analysis of the determinants of empowerment in the performance of the most important work of the audit committees, namely: supervising the process of preparing reports, supervising the system of intern
... Show MoreThis study aims at identifying the role played by Public Relations in the field of security awareness of the dangers of terrorism. The research is directed to the employees at the Directorate General of Public Relations and Media at the Ministry of Interior. And that on the basis that those who play an important role in the security awareness are the security institutions, primarily the Ministry of Interior, since this Directorate is responsible for all subjects related to the public security using public relations science. It aims at identifying the functions, methods and communication tools used by the Directorate to raise awareness about the dangers of terrorism. In order to achieve the research objectives, the researcher uses the sur
... Show MoreAbstract:
The issues related to foreign trade is a broad field for discussions and captures the interest of economists for their contribution to the process of economic development in the economies of the countries, especially developing ones. The imports of goods and services in foreign trade constitute an important part of the local by which the economy gets goods and services that the economy cannot produce because of the incompetent base of production. Further, the demand function of imports occupied a good deal of the attention of researchers in the field of international economics for which agricultural imports constitute an important part. The reason for the interest in the subject is due to its im
... Show MoreBackground: the novel coronavirus (2019-ncov), formally known as severe acute respiratory syndrome coronavirus 2 (sars-cov-2), the etiological cause of the (corona virus disease 2019) covid-19, appeared in wuhan, hubei province, china. On 11 march 2020, the world health organization (who) declared this disease as a pandemic. As new information on the clinical characteristics, treatment options, and outcomes for covid-19 emerges approximately every hour, physicians should keep themselves up-to-date on this topic.
Objective: to study the demographic features, clinical signs and symptoms and certain vital and laboratory findings of covid-19 hospitalized cases; and to identify the used medication, complications, length of stay at the hosp
Background: Ovulation induction by human menopausal gonadotrophin (HMG) results in temporal luteal phase defect. Luteal support therapies are required to support embryo implantation in stimulated cycle especially in luteal phase defect infertile women.
Objective: The objective of the present study was to investigate the clinical significance of progesterone, aspirin and HCG on human embryo implantation in women with luteal phase defect following ICSI and embryo transfer (ET).
Patients and Methods: The female patients were divided into six groups depending on the type of the luteal support protocols (LSP). Group 1 (No= 54), received 10 mg oral progesterone (P), group 2 (No= 35) received P plus HCG
Background: Thalassemias are a group of heterogeneous genetic disorders, in which the rate of production of hemoglobin is partially or completely suppressed due to reduced rate of synthesis of α or β- chain
Objectives: to estimate the prevalence of Hepatitis C infection among B thalassemia patients attending Ibn-AL-Baladi center of blood diseases in AL-Sader city, in AL-Resafa Quarter of Baghdad and to determine the possible risk factors.
Type of the study: Cross- sectional study.
Methods: A cross sectional study conducted on B Thalassemia patients attending the blood diseases center in Ibn-AL-Baladi hospital during the period from 1st
... Show MoreThis study is concerned measuri ng the concentration of some
ions l ike calci um, sodium, potassium, chlor, lithium, carbonate and bicarbonate in drinking and river water in AI-Muthana and AI-Basrah
cities_
These ions usually are found in normal water. When we take di!Ierent samples from different regions on the E uph rates river in Al Muthana and A1-Basrah cities we fou nd that the d rinking water in Al Basrah contains a high prccent from those ions. The low preccnt from those ions found in Arab river as compared with Euphrates river. This study
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