The standard formulation of Wave Intensity Analysis (WIA) assumes that the flow velocity (U) in the conduit is <;<; the velocity of propagation of waves (c) in the system, and Mach number, M=U/c, is negligible. However, in the large conduit arteries, U is relatively high due to ventricular contraction and c is relatively low due to the large compliance; thus M is > 0, and may not be ignored. Therefore, the aim of this study is to identify experimentally the relationship between M and the reflection coefficient in vitro. Combinations of flexible tubes, of 2 m in length with isotropic and uniform circular cross sectional area along their longitudinal axes, were used to present mother and daughter tubes to produce a range of reflection coefficients. An approximately semi-sinusoidal pulse was generated at the inlet of the mother tube using a syringe pump, first in the condition of initial velocity, U 0 =0, and when U 0 >0 with steady flow to superimpose the pulse. Pressure (P) and Velocity (U) were measured in the mother tube, wave speed was determined using the foot to foot and PU-loops methods. The theoretical reflection coefficient, R t at M=0, has been compared to the experimental reflection coefficient, R at M>0, which was determined as dP-/dP+ as calculated using WIA. The function R(M) changes significantly with the geometrical and mechanical features of the connected tubes. In our experiments, R increased significantly with small values of M. In the range of M=0-0.02, R increased by 4-36%. Therefore, we conclude that M significantly affects the magnitude of reflections.
ABSTRACT Porous silicon has been produced in this work by photochemical etching process (PC). The irradiation has been achieved using ordinary light source (150250 W) power and (875 nm) wavelength. The influence of various irradiation times and HF concentration on porosity of PSi material was investigated by depending on gravimetric measurements. The I-V and C-V characteristics for CdS/PSi structure have been investigated in this work too.
This study includes replication and attenuation of foot and mouth disease virus type O which isolated from infected calves. Many passages for the virus in chick-Embryo were established as a substitute method to the tissue culture which is highly caustic in contrast to the chick embryo. The virus passed ten consequent passages which lead to the reduce of the titer of the virus from 106.53 TCID50/ 0.1 ml in cattle testis tissue culture to 103 TCID50/ 0.1 ml. the pathogenecity of attenuated FMD virus were also studied in both chick-embryo and guinea pigs. Using agar gel diffusion test precipitation antibodies was detected in guinea pig serum after 14 and 21 days post exposure to the attenuated virus. The inoculated guine
... Show MoreAfter the year 2003, Iraq went through multiple waves of violence and at different levels on the security, intellectual, political and social levels. Behind that stood several motives and incentives to enable violence that represented the first axis of research, the most important of which was the political motives that circulated an atmosphere that politics against society and transformed power into a field of political brutality against the individual and the group at once. There are also cultural, intellectual, media and economic motives such as weak cultural independence, poverty, marginalization, unemployment and want, and the absence of a media discourse that rejects violence but incites it, on the other ha
... Show MoreMost of the literature on the management and application terkzat waved the last period on large organizations was the negligence of knowledge management in small organizations where research aims to find out knowleddge management, small projects In oxygen Ahli plant in Iraq, and the fact the role of knowledge management in small projects from the standpoint of employees in order to achieve this used production method results. The results showed that knowledge management has a role in the high level of productivity during the years 2010-2013. The results showed that knowledge management has a role in the high level of productivity during the years 2
... Show MoreBackground: In the Thermafil as a root canal obturation, system little is known about the effect that varying rates of insertion have on the adaptability of thermoplasticized GP and the amount of apical extrusion. Materials and methods: thirty simulated root canals were obturated with thermafil obturators and Apexit Plus sealer at three different insertion rates. The obturated canals were sectioned at three different levels, the sealer average film thickness for each section was calculated and the amount of apical extrusion for each canal was conducted. Results: the higher adaptability was seen with the faster insertion rate while the slower insertion rate showed fewer tendencies to cause apical extrusion. Conclusions: the intermediate i
... Show MoreThe main objectives of present study are to evaluate the trace elements pollution in the sediment of the Tigris River and drainage canals in Wasit Governorate, Iraq. Assessment of trace elements pollutants were conducted for 18 sediment samples collected in March 2017. Trace elements were analyzed in sediment Tigris River samples in Wasit Governorate. This metal pollution was evaluated using geo-accumulation (I-geo) index, Contamination Factor (CF) and Pollution Load Index (PLI). According to these statistical indices, the sediments collected from Tigris River in the study area are highly polluted with Titanium (71.9 ppm), Nickel (226.6 ppm) Chromium (425.2 ppm), Cadmium (2ppm) and Molybdenum (15.8 ppm) while the sediments&nb
... Show MoreThis research aims to focus on the reality of the imbalance of the balance of trade structure in order to improve it and determine the size of the imbalance as a result of dependence on one commodity, namely crude oil in the structure of exports versus the diversity of the structure of imports of various goods and goods.
In order to achieve that goal, a deductive approach was adopted, which included a shift from general theory data to special applications.
We have reached through the research to a number of conclusions, most notably the effectiveness of public spending in correcting the imbalance of the balance of trade structure during the study pe
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