A localized stenosis or aneurysm is a discontinuity that presents the pulse wave produced by the contracting heart with a reflection site. However, neither wave speed ( c) in these discontinuities nor the size of reflection in relation to the size of the discontinuity has been adequately studied before. Therefore, the aim of this work is to study the propagation of waves traversing flexible tubes in the presence of aneurysm and stenosis in vitro. We manufactured different sized four stenosis and four aneurysm silicone sections, connected one at a time to a flexible ‘mother’ tube, at the inlet of which a single semi-sinusoidal wave was generated. Pressure and velocity were measured simultaneously 25 cm downstream the inlet of the respective mother tube. The wave speed was measured using the PU-loop method in the mother tube and within each discontinuity using the foot-to-foot technique. The stenosis and aneurysm dimensions and c were used to determine the reflection coefficient ( R) at each discontinuity. Wave intensity analysis was used to determine the size of the reflected wave. The reflection coefficient increased with the increase and decrease in the size of the aneurysm and stenosis, respectively. c increased and decreased within stenosis and aneurysms, respectively, compared to that of the mother tube. Stenosis and aneurysm induced backward compression and expansion waves, respectively; the size of which was related to the size of the reflection coefficient at each discontinuity, increases with smaller stenosis and larger aneurysms. Wave speed is inversely proportional to the size of the discontinuity, exponentially increases with smaller stenosis and aneurysms and always higher in the stenosis. The size of the compression and expansion reflected wave depends on the size of R, increases with larger aneurysms and smaller stenosis.
Labrotary experiment was conducted to study the effect of different levels of nematode population densities of Meloidogyne spp on seed germination percentage and seedling characteristics of Vigna sinensis, Ahelmoschus esculentus, Cicer arietinum, Helianthus annuus and Rap-hanus sativus. Four different levels of nematode populat-ion densities ranged from 1 to 4 prepared from radish in-fected roots and used as inoculating agent to infect all seed types in the experiment Seed germination percentage of Vigna sinensis and Ablemoschus eseulentus were highly reduced (at 0.01 level of significance) with increased nematode population level from 1 to 4. Seedling length of the remaining seed types were significantly reduced (at 0.01 level of signif
... Show MoreFour local hemolysin producer bacterial isolates were selected, tow of them gram negative bacteria (Escherichia coli ,Pseudomonas aeruginosa ) and the other two were gram positive bacteria (Staphylococcus aureus , Bacillus cereus ). Minimum inhibitory concentration of the aqueous and alcoholic extracts of Punica granatum L. pericarp were determined towards the four bacterial isolates ,results obtaind showed that MICs of the aqueous extract were 200 mg/ml for E .coli and P. aeruginosa isolates while were 5 mg/ml and 2 mg/ml for B. cereus, S. aureus , respectively The MICs for the ethanolic extract were 50 mg/ml , 20 mg/ml ,1 mg/ml ,0.5 mg/ml for E. coli ,P. aeruginosa ,B. cereus ,S. aureus , respectively. The effect of Sub-MICs o
... Show MoreThe present study aims at examining the stylistic development in the crafts of the sculptor Mohammed Ghani Hikmat. It gives answers to the following two questions: what is the nature of the stylistic development? And what are these principles and techniques led him to this development? The researcher has used the descriptive, analytic approach in examining the selected five samples out of the sculptor’s displayed crafts. The observational technique is used as a tool of examination. Among the main findings are: integrating space in the cubic crafts, represented by the existence of holes within this general construction of that space; the evident influence of critical contemporary orientations through the direct insertion of recipients i
... Show MoreAppending is a morphological term which means the addition of one or two letters to a structure to be similar to other structures of well-known abstractor additional nouns and verbs constructions. The goal of appending is to organize what have been expanded linguistically and collect similarities to reduce the syntactic rules. This is because the appended word exists for expanding purposes; however, it has no construction of its own. An appending was included with another construction with mentioning the additional letter. This by itself means that appending as a process is a term that helps organize rather than expand language. Scholars further noticed that the appending letter is not semantically significant, and so it differs from the
... Show MoreThe Providence of the Rosaly's family to the Intellectual Movement in Yemen
the contemporary Arab scholars deal with semiotics as an approach that helps them understand the texts, its meaning, and its structural functionalism . that’s why every now and then we find some
studies and researches using semiotics as an approach in study and comparatives, some of them even used the semiotic approach in analyzing old and new texts, while others think that semiotic holds and important place in critical approaches .
even though some of them considers semiotic just a trend of fashion this really didn’t lessen the value of semiotic as a scientific and procedural approach in literary and media studies as well as in analyzing literary and journalistic texts. for this reason it is considered as an important approa
The current research dealt with (the deliberative dimension of the visual sign in the contemporary Iraqi poster) in an attempt to identify the importance of the contemporary poster and the role of the international dimension of the visual sign of exceptional importance.
What is the international dimension of the visual mark?
- What is the effect of the visual label on the contemporary Iraqi poster?
The current research aims to identify the pragmatic dimension in the contemporary Iraqi poster.
Across the temporal and spatial research boundaries of the year (2000-2020) in Iraq. The limits of the objective research The limits of this study on the pragmatics in the visual sign and the determination of the relationship betwee
Aqueous root extract has been used to examine the green production of silver nanoparticles (AgNPs) by reducing the Ag+ ions in a silver nitrate solution. UV-Vis spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy (FTIR) were used to analyze the produced AgNPs. The AgNPs that were created had a maximum absorbance at 416 nm, were spherical in form, polydispersed in nature, and were 685 nm in size.The AgNPs demonstrated antibacterial efficacy against Escherichia coli and Staphylococcus. The dengue vector Aedes aegypti's second instar larvae were very susceptible to the AgNPs' powerful larvicidal action.