The hydraulic behavior of the flow can be changed by using large-scale geometric roughness elements in open channels. This change can help in controlling erosions and sedimentations along the mainstream of the channel. Roughness elements can be large stone or concrete blocks placed at the channel's bed to impose more resistance in the bed. The geometry of the roughness elements, numbers used, and configuration are parameters that can affect the flow's hydraulic characteristics. In this paper, velocity distribution along the flume was theoretically investigated using a series of tests of T-shape roughness elements, fixed height, arranged in three different configurations, differ in the number of lines of roughness element. These elements were used to find the best configuration of roughness elements that can be applied to change the flow's hydraulic characteristics. ANSYS Parametric Design Language, APDL, and Computational Fluid Dynamics, CFD, was used to simulate the flow in an open channel with roughness elements. CFD can be used to study the hydrodynamics of open channels under different conditions with inclusive details rather than relying on the costly field and time-consuming. Runs were implemented with different conditions, the discharge, and water depth in upstream and downstream of the flume. T-shape roughness elements with height equal to 3cm placed in three different configurations, two lines, four lines, and fully rough configurations were tested. The results show that the effect of roughness elements increasing with increasing the number of lines of roughness elements. Cases of four lines and fully rough configurations have almost the same hydraulic performance by having the same results of the velocity decrease percentage, which is decreased by approximately about 66% and 61% of the control case's velocity in the zone near the roughness elements consequently. But the difference is that four lines configuration is affected in a part of the test section. This behavior increases the velocity values by about 11% in the other side and by about 10% near the free surface in the case of four lines configuration and increased by about 32% above the roughness elements in a fully rough configuration.
Public relations have become vital functions in modern institutions in the complex business world. They play an important role in facilitating the process of communication between the institution and its audiences and achieve mutual understanding between the parties as public relations play this important role based on research and analysis, policy formulation and programming programs and communication with the public.
The significance of this research comes from the challenges faced by public relations in state institutions. Misunderstandings and ambiguities still plague most workers in this field, especially in defining the concept, objectives and basic functions of public rela
... Show MoreArchitecture forms theoretical summaries and multi systems that have the essence of change, and that what distinguishes Architecture from other sciences and their systems. Architecture means way of life via its expressional products and that appears through its systems. These systems are based on formative and technological properties in form, structure, services and materials as well as
their moral forms. All these are associated with techniques and facilities in order to establish integrated system.
Architectural creation does not come from void but it depends on a conception base to create a new condition for creative architectural product. The general problem of the research concentrated on limited theoretical and practica
Before the unit environmental problems serious the issues of the environment and conservation of contemporary issues important in the developed and developing worlds, it was natural that leads increasing global awareness to alert a group of intellectuals, scientists and politicians to the seriousness of this problem and the call to take steps deeper and more comprehensive with respect to the environment humanitarian based on the study of the various elements of this environment and a greater understanding of the relationships among them, and on this basis, steps have been taken to target the environment and to identify problems and make efforts to achieve the goals I: stop the deterioration of the environment and the second impro
... Show MoreBackground: Periodontal diseases are initiated by microbial plaque, which accumulates in the sulcular region and induces an inflammatory response. The Receptor activator of nuclear factor-kappa B ligand / osteoprotegerin (RANKL/OPG) axis is involved in the regulation of bone metabolism in periodontitis, in which an increase in receptor activator of nuclear factor-kappa B ligand or a decrease in osteoprotegerin can tip the balance in favor of osteoclastogenesis and the resorption of alveolar bone that is the hallmark of periodontitis. This study was performed to investigate the role of salivary levels of RANKL and OPG in pathogenesis of chronic periodontitis. Subjects and Methods: Fifty five subjects with chronic periodontitis with ages rang
... Show MoreThe proliferation of electronic games, video games and computers has caused children and teenagers to become attracted to these games and become their favorite entertainment. The widespread of these games has generated widespread debate about positive aspects and negative aspects. It is evident that there are two main trends in the impact of electronic games on the behavior of children and adolescents. The first trend is that e-games have positive effects on children and adolescents, especially in cognitive abilities and skills in learning. While the second view sees that electronic games have negative effects that appear in social isolation and lack of movement and aggression. Through the review of previous literature, the current resea
... Show MoreA summary of zooplankton research done in Peruvian marine waters is presented. We first provide a brief overview of the evolution of zooplankton studies off Peru before reviewing zooplankton biodiversity, regional distribution, seasonal and interannual fluctuation, trophodynamics, secondary production, and modeling are some of these topics. We evaluate research on various meroplankton, macroplankton, mesoplankton, and microplankton groups and provide a list of species from both published and unpublished sources. Three regional zooplankton groups have been identified: A shelf group on the continental shelf dominated by Acartia tonsa and Centropages brachiatus; A slope group on the continental shelf with siphonophores, bivalves, foramin
... Show MoreDegradation is one of the key processes governing the impact of pharmaceuticals in the aquatic environment. Most studies on the degradation of pharmaceuticals have focused on soil and sludge, with fewer exploring persistence in aquatic sediments. We investigated the dissipation of 6 pharmaceuticals from different therapeutic classes in a range of sediment types. Dissipation of each pharmaceutical was found to follow first‐order exponential decay. Half‐lives in the sediments ranged from 9.5 (atenolol) to 78.8 (amitriptyline) d. Under sterile conditions, the persistence of pharmaceuticals was considerably longer. Stepwise multiple linear regression analysis was performed to
Ismailism is of great importance in Islamic history and Islamic political thought. In different countries of the Muslim world today their presence exists and is active but is confused with mystery and secrecy. The most important characteristic of their political ideology is their dependence on the esoteric exegesis, which they have made an intellectual basis for which their most ideas relate, when they make for everything visible and exposed a hidden matter, not only aware of the esoteric exegesis, which only God knows and entrenched in science, and they mean imams or whoever They are called "(esoteric)" as a result of the Ismaili belief in esoteric interpretation and that everything is apparent inward, as well as they called the ((seven
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