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 Leishmania species are intracellular protozoan parasites that spend a portion of their life cycle in the midgut of sand flies and the remainder in the tissues of mammals. These parasites, which cause a class of human disorders known as leishmaniasis, live mostly in macrophages, where they multiply and survive by employing a variety of defense mechanisms against the oxidative stress and acidity generated by these immune cells. To help control their reaction to heat stress, they also produce heat shock proteins. Furthermore, the promastigote form has a glycocalyx that is necessary for colonizing the gut wall of the sand fly and completing its life cycle. Consequently, a variety of virulence factors contribute to the parasite's pathog
... Show MoreIntroduction and Aim: Bacteriocins are antimicrobial peptides that have bactericidal and/or bacteriostatic activity against other bacteria. The aim of this study was to assess the antibacterial efficiency of Klebocin a K. pneumoniae bacteriocin, against biofilm formation by clinical isolates of methicillin resistant Staphylococcus aureus MRSA. Materials and Methods: S. aureus isolated from clinical samples was identified according to vitek 2 system Antibiotic susceptibility test was performed according to disc diffusion method. Vitek 2 compact system was also used to detect MRSA strains. Agar well diffusion method was used to evaluate the antibacterial activity of klebocin from K. pneumoniae towards 11 strains of S. aureus by
... Show Morethe physical paraneters of oxadizole derivaties as donor molecules have been measured the charge transfer and methanol as solvent have been estimated from the electonic spectra
The notion of interval value fuzzy k-ideal of KU-semigroup was studied as a generalization of afuzzy k-ideal of KU-semigroup. Some results of this idea under homomorphism are discussed. Also, we presented some properties about the image (pre-image) for interval~ valued fuzzy~k-ideals of a KU-semigroup. Finally, the~ product of~ interval valued fuzzyk-ideals is established.
In this paper, An application of non-additive measures for re-evaluating the degree of importance of some student failure reasons has been discussed. We apply non-additive fuzzy integral model (Sugeno, Shilkret and Choquet) integrals for some expected factors which effect student examination performance for different students' cases.
Teikyo Medical and medicine Journal (ISSN:03875547) is a monthly peer reviewed fast publishing international medical and medicine journal that aims to publish good quality of Medical and pharmaceutical, medicine and health science Journal.
The study of cooperative education is important not only for researchers but also for those interested in studying educational methods, such as university professors, teachers in schools, and all educational institutions. This is because of its effectiveness in teaching students, developing their skills, developing their ideas and employing them in the study and finding appropriate solutions to the questions posed by the teacher. It also helps in instilling a spirit of cooperation among the students by dividing them into groups to achieve the desired goals. The aim of the study is to clarify how important it is for teachers to use cooperative education in addressing the educational, social and psychological aspects when teaching stu
... Show MoreIn this paper, the probabilistic behavior of plain concrete beams subjected to flexure is studied using a continuous mesoscale model. The model is two-dimensional where aggregate and mortar are treated as separate constituents having their own characteristic properties. The aggregate is represented as ellipses and generated under prescribed grading curves. Ellipses are randomly placed so it requires probabilistic analysis for model using the Monte Carlo simulation with 20 realizations to represent geometry uncertainty. The nonlinear behavior is simulated with an isotropic damage model for the mortar, while the aggregate is assumed to be elastic. The isotropic damage model softening be
This paper displays a survey about the laboratory routine core analysis study on ten sandstone core samples taken from Zubair Reservoir/West Quarna Oil Field. The Petrophysical properties of rock as porosity, permeability, grain's size, roundness and sorting, type of mineral and volumes of shales inside the samples were tested by many apparatus in the Petroleum Technology Department/ University of Technology such as OFITE BLP-530 Gas Porosimeter, PERG-200TM Gas Permeameter and liquid Permeameter, GeoSpec2 apparatus (NMR method), Scanning Electron Microscopy (SEM) and OFITE Spectral Gamma Ray Logger apparatus. By comparing all the results of porosity and permeability measured by these instruments, it is clear a significant vari
... Show MoreAbstract
Robotics manipulators with structural flexibility provide an attractive alternative to rigid robotics manipulators for many of the new and evolving applications in robotics. In certain applications their use is unavoidable. The increased complexity in modeling and control of such manipulators is offset by desirable performance enhancements in some respects. In this paperthe single- link flexible robotics manipulator was designed and implemented from Perspex and designed with 0.5 m length , 0.02 m width and with 0.004 m thickness with mass located at the tip. There are four subsystems; motion, control, accelerometer and gyro and a host computer subsystem. The work principle of single-link robotics manipul
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