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 .
In spite of increasing clinical cases which caused by enteroviruses transferred by water and no documents about entericviruses in the Iraqi water standards. The use of coliphages as an indicator of enteroviruses and fecal pollution were suggested two procedures were applied . The first is Two-Step Enrichment Method and the second is Single Agar Layer Method. Both methods gives good results in Identification of coliphages through testing fifty different water samples (Tap water, Surface water and Bottled water) the study shows the presence of coliphages in fourteen samples.
هذه الدراسة مكرسة للخصائص الوظيفية والدلالية المعقدة للفئات اللفظية من التوتر والنوع في اللغة الروسية سيتم الكشف في هذه الدراسة عن السمات الدلالية والأسلوبية للفرق بين الأفعال المكتملة وغير المكتملة، قد تكون الاختلافات مرتبطة بخصائص المعاني المعجمية للكلمات، وكذلك معاني اللواحق المكونة للكلمات) السوابق واللواحق). يعكس استخدام هذه الفئة النحوية في أنماط مختلفة بوضوح تفاصيل كل منها، لأن درجة واقعية ال
... Show MoreStatisticians often use regression models like parametric, nonparametric, and semi-parametric models to represent economic and social phenomena. These models explain the relationships between different variables in these phenomena. One of the parametric model techniques is conic projection regression. It helps to find the most important slopes for multidimensional data using prior information about the regression's parameters to estimate the most efficient estimator. R algorithms, written in the R language, simplify this complex method. These algorithms are based on quadratic programming, which makes the estimations more accurate.
ABSTRACT This paper has a three-pronged objective: offering a unitary set of semantic distinctive features to the analysis of nominal “hatred synonyms” in the lexicon of both English and Standard Arabic (SA), applying it procedurally to test its scope of functionality crosslinguistically, and singling out the closest noun synonymous equivalents among the membership of the two sets in this particular lexical semantic field in both languages. The componential analysis and the matching procedures carried have been functional in identifying ten totally matching equivalents (i.e. at 55.6%), and eight partially matching ones (i.e. at %44.4%). This result shows that while total matching equivalences do exist in the translation of certain Eng
... Show MoreThe main aim of the current research is to focus the light on some bacterial contamination on cracked eggshell and egg content plus studying the sensitivity of these bacterial isolates to antibiotics. For this purpose, a total of 50 eggs were collected from the markets in Baghdad city (Iraq) and examined for bacterial isolation from cracked eggshells and from the egg contents. The bacterial isolates were cultured and purified then transferred to a specific media to study its sensitivity against antibiotics. The results revealed that bacteria isolated from both cracked eggshells (46%) and egg contents (44%). The bacteria isolated include E. coli, Staphylococcus, Enterococcus faecalis, Enterobacter and Pseudomonas. The results of antibiotic s
... Show MoreIntroduction:Serratia marcescens is a gram-negative pathogen of many species. Its pathogenicity and survival are linked to its capacity to build biofilms as well as its strong inherent resistance to antimicrobials and cleaning agents. Objectives: To analyse the impact of glyceryl trinitrate (GTN) on the gene expression of QS-related genes (rssB, rsmA,and pigP) of S. marcescens. Methodology: The broth microdilution technique estimated the bactericidal effectiveness of glyceryl trinitrate. The presence of rssB, rsmA,and pigP in S. marcescens isolates was detected using PCR. qRT-PCR was used to assess the effect of GTN on rssB, rsmA,and pigPgene expression. Results: The results demonstrated that GTN has no effect on S. marcesce
... Show MoreEsterification reaction is most important reaction in biodiesel production. In this study, oleic acid was used as a suggested feedstock to study and simulate production of biodiesel. Batch esterification of oleic acid was carried out at operating conditions; temperature from 40 to 70 °C, ethanol to oleic acid molar ratio from 1/1 to 6/1, H2SO4 as the catalyst 1 and 5% wt of oleic acid, reaction time up to 180 min. The optimum conditions for the esterification reaction were molar ratio of ethanol/oleic acid 6/1, 5%wt H2SO4 relative to oleic acid, 70 °C, 90 min and conversion of oleic 0.92. The activation energy for the suggested model was 26625 J/mole for forward reaction and 42189 J/mole for equilibrium constant. The obtained results s
... Show MoreVitamin E, having the well known antioxidant activity through scavenging free radicals و it occurs in several isomeric forms , these isomers have relatively different functions . One of these actions is related to its ability to inhibit platelets aggregation and hence thrombosis. The present study included a total number of apparently healthy 62 males . 11of them served as standard group , treated with 100 mg aspirin /day for more than one month . Another 31 subjects were randomly grouped into 5 groups that received different daily doses of α – tocopherol : 400 IU , 800 IU and 1200 IU for 2-6 months.The remainder ( 20 ) subjects served
... Show MoreObjective(s): To evaluate students’ communication skills and their academic performance; to compare between the students relative to communication skills and their academic performance in the University of Baghdad and to identify the relationship between students’ communication skills, academic performance and their socio-demographic characteristics of age, gender, grade and socioeconomic status. Methodology: A descriptive design, using the evaluation approach, is carried through the present study to evaluate colleges’ students’ communication skills and their academic performance in the University of Baghdad for the period of January 7th 2019 to August 28th 2019. A non-probability, purposive sample, of (80) university students, i
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