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.
In this research, the influence of the orientation and distance factors on the lowest usable frequency (LUF) parameter has been studied theoretically. The calculations of the (LUF) parameter have been made using the (VOACAP) international communication model for the connection links between the capital Baghdad and many other locations that distributed on different distances and directions over the Middle East region. The results shown in this study indicate there is a slight affection of the link direction (orientation) on the LUF parameter, while the influence of the distance factor is more significant on the values of the LUF parameter. The day/night effect appears for the long distance HF links (i.e. more than a 500 Km)
The goal of current research is to identify the difficulties in the application of modern physics in the middle schools of the province of Baghdad schools from the perspective of teachers of physics trends, sample search of (127) teachers, Karkh Third Directorate, and use Researcher questionnaire data collection tool after applying it to teachers who have experience (5) years and more after confirmation of the validity and reliability of the scale (the tool) researcher has used the averages for the purpose of interpreting the results. the results showed that the difficulties have been in the order following: (difficulties related educational environment of modern trends of teaching, curriculum-related dif
... Show MoreEstimation of the unknown parameters in 2-D sinusoidal signal model can be considered as important and difficult problem. Due to the difficulty to find estimate of all the parameters of this type of models at the same time, we propose sequential non-liner least squares method and sequential robust M method after their development through the use of sequential approach in the estimate suggested by Prasad et al to estimate unknown frequencies and amplitudes for the 2-D sinusoidal compounds but depending on Downhill Simplex Algorithm in solving non-linear equations for the purpose of obtaining non-linear parameters estimation which represents frequencies and then use of least squares formula to estimate
... Show MoreThe increase of the scenographic designer role on account of the character of the director in the Iraqi theater constituted a clear phenomenon that has been manifested in many shows, which necessitated a stance on the nature of this relation and delimiting the work space for each one of them inside the theater show. The research focuses on determining the work relation between the directorial vision and the scenographic proposal in the Iraq theater show. The research is divided into four chapters, the first one addressed the methodological framework, where the research problem was stated in the following question (has the scenographic designer been able through his scenographic proposal to remove the director from his position being the
... Show MoreThe research aims to define the main and subsidiary criteria for evaluating the industrial market sectors and proposing a model for arranging these criteria according to priority and knowing the highest criteria in terms of relative importance in the General Company for Automobile Trade and Machinery, and for the purpose of establishing this model, experiences in the concerned company were approved, and this study proposes a multi-criteria decision model According to the FEAHP, the expanded fuzzy hierarchical analysis method enables the commercial company to develop clear strategic policies on which the company’s management system depends on determining criteria for evaluating and selecting market sectors and making appropriate
... Show MoreIn the age of information and communication revolution, education as one of life
aspects has influenced with that revolution by integrating technology in education, which
have become as an important learning tools of the whole educational process . Technology,
when used appropriately, can help make science classroom a site of active learning and
critical thinking, furthering student inquiry and connections with different materials. It is
necessary to develop human rights education programs and materials for discretionary and
extracurricular activities as it provide them with the skills and tools so that they are
empowered to take action to realize their rights. Human rights education is a critical means of
instill
This study aimed at revealing the degree of availability of standards of word problems in mathematics books for the first three grades of the basic stage in Palestine. For this purpose, the researcher prepared an analysis tool and a list of criteria consisting of two areas: linguistic formulation and mathematical content. Every area had seven items. The results of the study showed that the third-grade mathematics book has the highest degree of availability of the standards with 85.75%, and then came the second-grade mathematics book with 83.12%. Finally, the first-grade mathematics book came with 80.13%. In the light of the previous results, the researcher recommended to develop the language of word problems, to take into account their i
... Show MoreAbstract Background: Articular cartilage lesions in the knee joint are frequently seen,its treatment represents a challenge for orthopedic surgeons especially in young age patients and if left untreated,then they can progress to advanced osteoarthritis that may affect the functional status of the patients.Many treatment modalities had developed for these lesions, in the current study arthroscopic micro fracture plus intra articular whole bone marrow(WBM) injection was used as modality of treating these lesions. Objectives: to assess the effectiveness of arthroscopic micro fracture plus WBM intra articular injection as a treatment modality for knee articular cartilage lesions. Patients and Methods : a prospective experimental study was perf
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