The effect of time (or corrosion products formation) on corrosion rates of carbon steel pipe in aerated 0.1N NaCl
solution under turbulent flow conditions is investigated. Tests are conducted using electrochemical polarization
technique by determining the limiting current density of oxygen reduction in Reynolds number range of 15000 to 110000
and temperature range of 30 to 60oC. The effect of corrosion products formation on the friction factor is studied and
discussed. Corrosion process is analyzed as a mass transfer operation and the mass transfer theory is employed to
express the corrosion rate. The results are compared with many proposed models particularly those based on the
concept of analogy among momentum, heat, and mass transport. The capability of these models to predict corrosion
rates in presence of corrosion products is examined and discussed. It is found that formation of corrosion products with
time decreases the corrosion rate (or mass transfer rate) at low Reynolds number and temperature while it increases the
corrosion rate at high Re and temperature. It increases momentum transport and this increase depends on temperature,
Reynolds number, and corrosion rate. Increasing roughness due to the formation of corrosion products causes
overestimation of analogy correlations results by increasing friction factor and decreasing corrosion rate.
Abstract
This study investigated the optimization of wear behavior of AISI 4340 steel based on the Taguchi method under various testing conditions. In this paper, a neural network and the Taguchi design method have been implemented for minimizing the wear rate in 4340 steel. A back-propagation neural network (BPNN) was developed to predict the wear rate. In the development of a predictive model, wear parameters like sliding speed, applying load and sliding distance were considered as the input model variables of the AISI 4340 steel. An analysis of variance (ANOVA) was used to determine the significant parameter affecting the wear rate. Finally, the Taguchi approach was applied to determine
... Show MoreNeonatal sepsis refers to the bacterial bloodstream infections of the newborn during the neonatal period as usually the first twenty-eight days of life. The current study was done in the laboratories of AL-Batool Teaching Hospital for Gynecology and Pediatrics in Baqubah, Diyala Governorate, including 140 blood specimens collected from the neonates admitted to the hospital with suspected sepsis, the ages of the both groups was ranged from 1 day to 28 days. Out of the total cultured samples, 32.14% (45 of 140) were positive and 67.86% (95 of 140) were negative blood culture. 45 of 140 samples were negative to the blood culture chosen as control group. The results showed highest isolates were Coagulase Negative Staphylococcus (CoNS) 19 (42.2%
... Show MoreThe change in the size of the droplets during the pesticide application process could have a negative impact on the percentage of drift or the losses of pesticides to the environment. One of the factors that could affect the droplet size produced from a single nozzle is the internal design of the nozzle itself, in addition to the wear of the nozzle orifice as a result of the usage time. In this research, three types of nozzles with different internal designs were used (Turbo TeeJet (TT), Turbo TwinJet (TTj 6011003), and Drift Guard (DG 11003)). The nozzles were subjected to an accelerated wear test for one hundred hours, and different droplet size parameters (Dv 0.1, Dv 0.5, Dv 0.9),
This paper presents a nonlinear finite element modeling and analysis of steel fiber reinforced concrete (SFRC) deep beams with and without openings in web subjected to two- point loading. In this study, the beams were modeled using ANSYS nonlinear finite element
software. The percentage of steel fiber was varied from 0 to 1.0%.The influence of fiber content in the concrete deep beams has been studied by measuring the deflection of the deep beams at mid- span and marking the cracking patterns, compute the failure loads for each deep beam, and also study the shearing and first principal stresses for the deep beams with and without openings and with different steel fiber ratios. The above study indicates that the location of openings an
Prediction of the formation of pore and fracture pressure before constructing a drilling wells program are a crucial since it helps to prevent several drilling operations issues including lost circulation, kick, pipe sticking, blowout, and other issues. IP (Interactive Petrophysics) software is used to calculate and measure pore and fracture pressure. Eaton method, Matthews and Kelly, Modified Eaton, and Barker and Wood equations are used to calculate fracture pressure, whereas only Eaton method is used to measure pore pressure. These approaches are based on log data obtained from six wells, three from the north dome; BUCN-52, BUCN-51, BUCN-43 and the other from the south dome; BUCS-49, BUCS-48, BUCS-47. Along with the overburden pr
... Show MorePrediction of the formation of pore and fracture pressure before constructing a drilling wells program are a crucial since it helps to prevent several drilling operations issues including lost circulation, kick, pipe sticking, blowout, and other issues. IP (Interactive Petrophysics) software is used to calculate and measure pore and fracture pressure. Eaton method, Matthews and Kelly, Modified Eaton, and Barker and Wood equations are used to calculate fracture pressure, whereas only Eaton method is used to measure pore pressure. These approaches are based on log data obtained from six wells, three from the north dome; BUCN-52, BUCN-51, BUCN-43 and the other from the south dome; BUCS-49, BUCS-48, BUCS-47. Along with the overburden pressur
... Show MoreObjective: the objective of this study was to compare the intraoperative blood loss, intraoperative time, postoperative pain and secondary hemorrhage between electrodissection and cold steel dissection tonsillectomy.
Methods: One hundred and six patients were enrolled in this study, the patients were randomly allocated into electrodissection group A (n=51) and cold steel dissection tonsillectomy group B (n=53). All patients are above 7 years and had history of recurrent tonsillitis and/or tonsillar hypertrophy with obstructive symptoms. Intraoperative parameters and postoperative outcome were assessed.
Results: In group A patients had statically significa
... Show MoreIn this paper, Nordhaus-Gaddum type relations on open support independence number of some derived graphs of path related graphs under addition and multiplication are studied.
Automatic speaker recognition may achieve remarkable performance in matched training and test conditions. Conversely, results drop significantly in incompatible noisy conditions. Furthermore, feature extraction significantly affects performance. Mel-frequency cepstral coefficients MFCCs are most commonly used in this field of study. The literature has reported that the conditions for training and testing are highly correlated. Taken together, these facts support strong recommendations for using MFCC features in similar environmental conditions (train/test) for speaker recognition. However, with noise and reverberation present, MFCC performance is not reliable. To address this, we propose a new feature 'entrocy' for accurate and robu
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