Dam and powerhouse operation sustainability is a major concern from the hydraulic engineering perspective. Powerhouse operation is one of the main sources of vibrations in the dam structure and hydropower plant; thus, the evaluation of turbine performance at different water pressures is important for determining the sustainability of the dam body. Draft tube turbines run under high pressure and suffer from connection problems, such as vibrations and pressure fluctuation. Reducing the pressure fluctuation and minimizing the principal stress caused by undesired components of water in the draft tube turbine are ongoing problems that must be resolved. Here, we conducted a comprehensive review of studies performed on dams, powerhouses, and turbine vibration, focusing on the vibration of two turbine units: Kaplan and Francis turbine units. The survey covered several aspects of dam types (e.g., rock and concrete dams), powerhouse analysis, turbine vibrations, and the relationship between dam and hydropower plant sustainability and operation. The current review covers the related research on the fluid mechanism in turbine units of hydropower plants, providing a perspective on better control of vibrations. Thus, the risks and failures can be better managed and reduced, which in turn will reduce hydropower plant operation costs and simultaneously increase the economical sustainability. Several research gaps were found, and the literature was assessed to provide more insightful details on the studies surveyed. Numerous future research directions are recommended.
It is well known that the spread of cancer or tumor growth increases in polluted environments. In this paper, the dynamic behavior of the cancer model in the polluted environment is studied taking into consideration the delay in clearance of the environment from their contamination. The set of differential equations that simulates this epidemic model is formulated. The existence, uniqueness, and the bound of the solution are discussed. The local and global stability conditions of disease-free and endemic equilibrium points are investigated. The occurrence of the Hopf bifurcation around the endemic equilibrium point is proved. The stability and direction of the periodic dynamics are studied. Finally, the paper is ended with a numerical simul
... Show MorePauses as pragmatic markers are considered important devices that help readers to gain a better and deeper understanding of certain texts as well as speech, promoting effectively language communication. They can help both the speaker and the hearer, due to the functions they have in a text. Their occurrence in speech has a value that they make it more understandable. In this regard, the present study aims to examine the forms and functions of pauses in literary texts, more specifically, in selected extracts from two dramas, namely, Pinter's The Homecoming and Baker's Circle Mirror Transformation and to compare how the two writers use pauses in these two dramas. To do so, the sequential production approach of turn-taking by Sacks, Sc
... Show MoreBanking institutions are considered one of development foundations,and they also performe active role in supporting national economey and itsinstitutions. Banks became diversed in their activities that specialized Banksbecame one of the constituents of developing work in any activity, especiallyin investiment sector .In view of the importance of insurance sector and thenecessity of developing its divices and its working instituments, studyinginsurance Banking reality became a necessity, because insurance Companies inIraq are suffering of weakness in the level of insurance service, in addition tothe existence of a problem in the relationship between Banks network andinsurance industry.So this research aims to define insurance reality; the
... Show MoreIt is not long time since globalization has started along with knowledge economy and, communication media and technical information control on the world. As a result serious events appeared like failure in businesses, financial corruption and shortage of administration and control.
In spite of the great efforts held by international organizations and foundations to find organizational frames that adopt independence, que
... Show MoreA particular solution of the two and three dimensional unsteady state thermal or mass diffusion equation is obtained by introducing a combination of variables of the form,
η = (x+y) / √ct , and η = (x+y+z) / √ct, for two and three dimensional equations
respectively. And the corresponding solutions are,
θ (t,x,y) = θ0 erfc (x+y)/√8ct and θ( t,x,y,z) =θ0 erfc (x+y+z/√12ct)
Geographic information system (GIS) is utilized in a variety of tasks such as, resource management, urban planning, emergency planning in case of accident, and rapid response etc. The aim of this study is to produce a digital map with the aid of GIS and a survey data. A survey data is conducted with Total Station technique on sanitary planning positions. The campus of Baghdad University is chosen to test the execution and accuracy of the results for sewer manholes locations. During the field survey, Total Station (Nikon Nivo) is used to identify the 3-D coordinates for each location. Finally, Geographical Information System (GIS) are utilized to present the digital map of the network sewer pipe line to the end users. Although Geographic Inf
... Show MoreWe prepared polythiophene (PTH) with single wall carbon nanotube (SWCNT) nanocomposite thin films for Nitrogen dioxide (NO2) gas sensing applications. Thin films were synthesized via electrochemical polymerization method onto (Indium tin oxide) ITO coated glass substrate of thiophene monomer with magnesium perchlorate and different concentration from SWCNT (0.012 and 0.016) % in the presence130mL of Acetonitrile used. X-ray diffraction (XRD), Field Emission Scanning Electron microscopy (FE-SEM), Atomic Force Microscope (AFM) and Fourier Transform Infrared Spectroscopy (FT-IR) were used to characterized these nanocomposite thin films. The response of these nanocomposite for NO2 gas was evaluated via monitoring the change
... Show MoreIraqi legislator taxation married women in charge of the income tax treatment of the man in charge of tax and the application of the principle of equality of individuals to bear public burdens. The factor legislator women in charge of special treatment in some cases, taking into account the circumstances family allow tax in the case of whether she was married to a man is unable to completely work and does not have a resource, as well as giving the legislator allow for her children. it observed that the amount of allowing still little is notcommensurate with the high cost of living in addition to limiting the tax allowances granted within the limits of the taxpayer and his immediate family did not take the legisla
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