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.
In an earlier paper, the basic analytical formula for particle-hole nuclear state densities was derived for non-Equidistant Spacing Model (non-ESM) approach. In this paper, an extension of the former equation was made to include pairing. Also a suggestion was made to derive the exact formula for the particle-hole state densities that depends exactly on Fermi energy and nuclear binding energies. The results indicated that the effects of pairing reduce the state density values, with similar dependence in the ESM system but with less strength. The results of the suggested exact formula indicated some modification from earlier non-ESM approximate treatment, on the cost of more calculation time
Abstract
The study of oxygen mass transfer was conducted in a laboratory scale 5 liter stirred bioreactor equipped with one Rushton turbine impeller. The effects of superficial gas velocity, impeller speed, power input and liquid viscosity on the oxygen mass transfer were considered. Air/ water and air/CMC systems were used as a liquid media for this study. The concentration of CMC was ranging from 0.5 to 3 w/v. The experimental results show that volumetric oxygen mass transfer coefficient increases with the increase in the superficial gas velocity and impeller speed and decreases with increasing liquid viscosity. The experimental results of kla were correlated with a mathematical correlation des
... Show MoreIn the marsh of the vast technical development and its reflections on the public life in all of its forms man lives in the shade of this and that and he is in a disprate need to took attentively at his reality through a new artistic vision which the imagination gives it , its value, from this point we find the designers pay great efforts in creating advertising designs that creation and fertile imagination are consisting one unit, and through her flying study on the reality of employing the creative imagination in the designing of printed advertisements, the researcher submitted her questions where some of which are: -What are the requirements of employing the creative imagination in the designing process? And -What are the machineries o
... Show MoreThe nuclear structure of 38Ar, 59Co, 124Sn, 146Nd, 153Eu and 203Tl target nuclei used in technology for nuclear batteries have been investigation, in order that, these nuclei are very interesting for radioisotope thermo-electric generator (RTG) space studies and for betavoltaic battery microelectronic systems. The single particle radial density distribution, the corresponding root mean square radii (rms), neutron skin thicknesses and binding energies have been investigated within the framework of Hartree-Fock Approximation with Skyrme interaction. The bremsstrahlung spectrums produced by absorption of beta particles in betavoltaic process and backscattered p
... Show MoreThis study was conducted to delineate diversity and species composition of non-diatoms planktonic algae in Hoor- Al- Azime marshes, Iran. The samples were collected from four sites at monthly basis from April 2011 to March 2012. A total 88 taxa were identified, out of which (40 taxa, 45.45%) belonging to Cyanophyta followed by Chlorophyta (29 taxa, 32.96%), Euglenophyta (18 taxa, 20.45%) and (1 taxa, 1.14%) of Dinophyta recorded. Comparing species richness (65 taxa, 34.76%) at Shat- Ali (St4) was the highest and the lowest (34 taxa, 18.18%) was observed at Rafi (St2). Species occurrence was associated with temperature where in summer (66 taxa) and (25 taxa) encountered winter. The phy
What concerns the research is employing the modern technology in a compatible way, because it has multiplied with the visual working functions and has grown in a special way with the development of the digital graphic design field which represents a crystallization product according to investigation and experimentation mechanism within the field of the scientific research in the design field and development of the skills of the first designing worker, who always seeks to find working and functional structures in order to produce a design with a clear meaning by utilizing the technological abilities including the acoustic tech
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... Show MoreThe importance of this research came through the question: Are there a privacy in the design in the ceramic arts, what are they? What are the basis of design for the ceramic art sculptures?The study refers to the design privacy in the contemporary ceramic arts, not as a serviceable art, but the art of being a dialectic collecting the arts across the craft and compositionThis research is the first study to look at the privacy of design and the connection with the formation of the large sizes ceramic art sculptures, and what they have as privacy of design and the way of formations.To highlight on the most prominent technical problems facing the ceramist in the production of so sculptural worksThe need for the study comes to help the worker
... Show MoreContemporary art has been widely affected by technology, and ceramics production is no exception. As an ancient art that originates from clay and other humble materials found in the ground, ceramics is considered one of the most adaptable art forms. Once it is realised how flexible ceramics as a material is, it can be easily altered into endless forms and shapes. Therefore, it is vital for ceramics practitioners to find a relationship between this wonderful material and the media of contemporary art, culture and modelling software or technology in general so that they can take their deformable art pieces to a whole new level. Such a relationship is worth investigating. Thus, for the purposes of this research, several ceramic pieces were
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