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 .
Investment in Human is one of the best and most important investments as it is renewed and developed resource over time in comparison with depleted material resources. Human resources is considered the part of the population that could be employed economically to contribute in increasing production energies as it is the support pillar of the society and have great energies that construct the society and raise of nations as well as he is distinguished with characteristics of ambitions to freedom.
Iraq is one of the countries that has large number of population in age of work and production and reduce in age dependent classes (children and old people).This dynamic in population led to step
... Show MoreWater injection equipments such as pipelines, which are used in the second recovery of oil in the Al-Ahdeb wells, suffer from the corrosion in water during maintaining vacuum deoxygenated tower that used to decrease concentration of the dissolved oxygen gas in the water from 6.2-9.1 ppm to o.5 ppm. This study involved calculation the corrosion rates of the internal surfaces of the
pipelines either during operation of the vacuum unit or when the tower out of operation. Finally, find the solution by one of the following suggestions. In the first suggestion removal of the dissolved O2 from water is achieved by increasing the dosage of the oxygen scavenger (sodium sulphite). The second suggestion involves removing the dissolved O2 from w
The electrical activity of the heart and the electrocardiogram (ECG) signal are fundamentally related. In the study that has been published, the ECG signal has been examined and used for a number of applications. The monitoring of heart rate and the analysis of heart rhythm patterns, the detection and diagnosis of cardiac diseases, the identification of emotional states, and the use of biometric identification methods are a few examples of applications in the field. Several various phases may be involved in the analysis of electrocardiogram (ECG) data, depending on the type of study being done. Preprocessing, feature extraction, feature selection, feature modification, and classification are frequently included in these stages. Ever
... Show MorePlacental dysfunction and or fetal central nervous system infestation caused by Human cytomegalovirus (HCMV) is the leading cause of congenital non-genetic neuro-developmental problems of the newborn, worldwide. Although the highest rates of congenital infection and CMV seroprevalence occurs in developing countries like Iraq, there remains a paucity of data from that part of the world. This descriptive case control study was undertaken in Babylon/ Iraq to determine the local seroprevalence of CMV in women of child bearing age, and to identify the socio-demographic factors associated with it. This study found a seropositivity peak amongst the 26-35 yr olds which declined in the 36 – 45 yr olds. However, the
... Show MoreResults of the current study demonstratedthat out of eighty-three isolatesof Pseudomonas aeruginosa,only twenty-five isolateswere resistant to five different antibiotics (of different classes) that were consequentlyconsideredmultidrug resistant isolates.These isolates developed variable susceptibility toward Eucalyptuscamaldulensisleavesoil (ECO). GC-MS analysis of ECOrevealed that the aromatic oil eugenol is the major constituent.However, the most frequent MIC was 0.39 µg/ml, while the lowest frequent MIC was 3.125 µg/ml.Moreover, this oil at ½ MIC (0.195µg/ml) increased the gene expression of exoU. Itis concluded from the outcomes of the studythat ECOmay cause severe damagewhen used to treat infections caused by P. aeruginosa.
... Show Moreهدفت هذه الدراسة إلى تحليل نتائج الاختبار الوطني الموحد الذي تطبقه وزارة التربية والتعليم الفلسطينية في مادة الرياضيات لطلبة الصف الثامن الأساسي في المدارس الحكومية في محافظة طولكرم، وذلك لمعرفة مستوى الطلبة على هذا الاختبار في ضوء متغيرات الجنس والمنطقة التعليمية ونوع المدرسة، ومعرفة علاقة التحصيل على هذا الاختبار بتحصيل الطلبة المدرسي والمعدل العام. ولتحقيق ذلك تم تحليل درجات (3218) طالباً وطالبة؛ وهم ي
... Show MoreThe investment portfolio of financial instruments & banking relatively new in the banking sector & the world of investment &capital markets in spite of its importance & its advantages in terms of the nature of the diversity of investment instruments as well as reduce the risk of investment & its contribution to the revitalization of the banks & the financial market , economic, &characterized by developments accelerated under information & communications technology , as is the portfolio tool vehicle of investment tools that provide for people who want to invest & they can not manag
... Show MoreThis study detects the presence of an important flavonoid "Casticin" in the fruits of Vitex agnus-castus L. grown in Iraq. The pharmaceutical importance of Casticin arise from its consideration as anti-tumor substance and have cytotoxic effects, and the absence of any study concerning Casticin content of this medicinal plant in Iraq, gave this study its importance. This study concerned with the extraction, identification, isolation and purification of Casticin from the fruits of Vitex agnus-castus L. The extraction of this compound was carried out using two methods. Identification of this compound was done by Thin Layer Chromatography (TLC) in which three different solvent system has been tried. This identif
... Show MoreThis study detects the presence of the most important steroidal sapogenin “Tigogenin†in the leaves of Yucca aloifolia widely cultivated in Iraq. The absence of any study concerning the Tigogenin content of this medicinal plant in Iraq, and the industrial importance of Tigogenin depending on its role as a precursor in the synthesis of some steroidal drugs, acquired this study its value. This study concerned with extraction, identification, isolation, and purification of Tigogenin from the leaves of Yucca aloifolia. Extraction of this compound was carried out using two methods. Identification of this compound was done using thin layer chromatography (TLC) where different solvent systems had been tried. Liberm
... Show MoreIn light of the corona pandemic, educational institutions have moved to learning and teaching via the Internet and e-learning ,and this is considered a turning point in course of higher education in Iraq in particular and education in general, which generated a great challenge for educational institutions to achieve the highest possible levels in practices and processes to reach the highest quality of their outputs from graduate students to the labor market that auditing performance by adopting e-learning standards is one of the effective tools that help the management of educational institutions by providing information on the ex
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