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Articles de revues sur le sujet "UPSTREEM LENGHT"
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Baskaran, Kabilan, et K. Srinivasan. « Effects of upstream pipe length on pipe-cavity jet noise ». Physics of Fluids 31, no 10 (1 octobre 2019) : 106103. http://dx.doi.org/10.1063/1.5120460.
Texte intégral
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Kozak, M. « Effects of intercistronic length on the efficiency of reinitiation by eucaryotic ribosomes ». Molecular and Cellular Biology 7, no 10 (octobre 1987) : 3438–45. http://dx.doi.org/10.1128/mcb.7.10.3438-3445.1987.
Texte intégralRésumé :
Simian virus 40-based plasmids that direct the synthesis of preproinsulin during short-term transfection of COS cells have been used to probe the mechanism of reinitiation by eucaryotic ribosomes. Earlier studies from several laboratories had established that the ability of ribosomes to reinitiate translation at an internal AUG codon depends on having a terminator codon in frame with the preceding AUG triplet and upstream from the intended restart site. In the present studies, the position of the upstream terminator codon relative to the preproinsulin restart site has been systematically varied. The efficiency of reinitiation progressively improved as the intercistronic sequence was lengthened. When the upstream "minicistron" terminated 79 nucleotides before the preproinsulin start site, the synthesis of proinsulin was as efficient as if there were no upstream AUG codons. A mechanism is postulated that might account for this result, which is somewhat surprising inasmuch as bacterial ribosomes reinitiate less efficiently as the intercistronic gap is widened.
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Kozak, M. « Effects of intercistronic length on the efficiency of reinitiation by eucaryotic ribosomes. » Molecular and Cellular Biology 7, no 10 (octobre 1987) : 3438–45. http://dx.doi.org/10.1128/mcb.7.10.3438.
Texte intégralRésumé :
Simian virus 40-based plasmids that direct the synthesis of preproinsulin during short-term transfection of COS cells have been used to probe the mechanism of reinitiation by eucaryotic ribosomes. Earlier studies from several laboratories had established that the ability of ribosomes to reinitiate translation at an internal AUG codon depends on having a terminator codon in frame with the preceding AUG triplet and upstream from the intended restart site. In the present studies, the position of the upstream terminator codon relative to the preproinsulin restart site has been systematically varied. The efficiency of reinitiation progressively improved as the intercistronic sequence was lengthened. When the upstream "minicistron" terminated 79 nucleotides before the preproinsulin start site, the synthesis of proinsulin was as efficient as if there were no upstream AUG codons. A mechanism is postulated that might account for this result, which is somewhat surprising inasmuch as bacterial ribosomes reinitiate less efficiently as the intercistronic gap is widened.
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El-Molla, Mohamed A., Naveen Y. Saad et Gada S. Ezizah. « Evaluation of Actual Creep Length Under Heading up Structures Aprons ». Journal of Engineering Research [TJER] 13, no 1 (1 avril 2017) : 14. http://dx.doi.org/10.24200/tjer.vol13iss1pp14-23.
Texte intégralRésumé :
In this paper a 2D finite element model (SEEP2D) is implemented to study the actual head loss along the sheet piles fixed at the ends of an apron of a heading up structure. Different scenarios for the thickness of the pervious layer under the apron, the length of the apron and the depths of the upstream and downstream sheet piles are studied. Results show that assuming the outer and inner faces of the sheet piles have the same weight for estimating the creep length while designing aprons of hydraulic structures is weak. Design equations for the actual head loss along the outer and inner faces for both the upstream and downstream sheet piles are driven. These equations can be used as a tool in the practical design for aprons of heading up structures formed on pervious soil and provided with upstream and downstream sheet piles at its ends.
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El-Molla, Mohamed, Naveen Y. Saad et Gada S. Ezizah. « Evaluation of Actual Creep Length Under Heading up Structures Aprons ». Journal of Engineering Research [TJER] 15, no 2 (7 novembre 2018) : 114. http://dx.doi.org/10.24200/tjer.vol15iss2pp114-123.
Texte intégralRésumé :
In this paper a 2D finite element model (SEEP2D) is implemented to study the actual head loss along the sheet piles fixed at the ends of an apron of a heading up structure. Different scenarios for the thickness of the pervious layer under the apron, the length of the apron and the depths of the upstream and downstream sheet piles are studied. Results show that assuming the outer and inner faces of the sheet piles have the same weight for estimating the creep length while designing aprons of hydraulic structures is weak. Design equations for the actual head loss along the outer and inner faces for both the upstream and downstream sheet piles are driven. These equations can be used as a tool in the practical design for aprons of heading up structures formed on pervious soil and provided with upstream and downstream sheet piles at its ends.
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El-Molla, Mohamed, Naveen Y. Saad et Gada S. Ezizah. « Evaluation of Actual Creep Length Under Heading up Structures Aprons ». Journal of Engineering Research [TJER] 15, no 2 (7 novembre 2018) : 14. http://dx.doi.org/10.24200/tjer.vol15iss2pp14-23.
Texte intégralRésumé :
In this paper a 2D finite element model (SEEP2D) is implemented to study the actual head loss along the sheet piles fixed at the ends of an apron of a heading up structure. Different scenarios for the thickness of the pervious layer under the apron, the length of the apron and the depths of the upstream and downstream sheet piles are studied. Results show that assuming the outer and inner faces of the sheet piles have the same weight for estimating the creep length while designing aprons of hydraulic structures is weak. Design equations for the actual head loss along the outer and inner faces for both the upstream and downstream sheet piles are driven. These equations can be used as a tool in the practical design for aprons of heading up structures formed on pervious soil and provided with upstream and downstream sheet piles at its ends.
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Wilkinson, John C., Enrique Cepero, Lawrence H. Boise et Colin S. Duckett. « Upstream Regulatory Role for XIAP in Receptor-Mediated Apoptosis ». Molecular and Cellular Biology 24, no 16 (15 août 2004) : 7003–14. http://dx.doi.org/10.1128/mcb.24.16.7003-7014.2004.
Texte intégralRésumé :
ABSTRACT X-linked inhibitor of apoptosis (XIAP) is an endogenous inhibitor of cell death that functions by suppressing caspases 3, 7, and 9. Here we describe the establishment of Jurkat-derived cell lines stably overexpressing either full-length XIAP or a truncation mutant of XIAP that can only inhibit caspase 9. Characterization of these cell lines revealed that following CD95 activation full-length XIAP supported both short- and long-term survival as well as proliferative capacity, in contrast to the truncation mutant but similar to Bcl-xL. Full-length XIAP was also able to inhibit CD95-mediated caspase 3 processing and activation, the mitochondrial release of cytochrome c and Smac/DIABLO, and the loss of mitochondrial membrane potential, whereas the XIAP truncation mutant failed to prevent any of these cell death events. Finally, suppression of XIAP levels by RNA interference sensitized Bcl-xL-overexpressing cells to death receptor-induced apoptosis. These data demonstrate for the first time that full-length XIAP inhibits caspase activation required for mitochondrial amplification of death receptor signals and that, by acting upstream of mitochondrial activation, XIAP supports the long-term proliferative capacity of cells following CD95 stimulation.
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Yoon, J. Y., N. W. Sung et C. H. Lee. « Effect of distance between 90° elbow close to upstream of orifice plate and the orifice plate on discharge coefficient ». Proceedings of the Institution of Mechanical Engineers, Part E : Journal of Process Mechanical Engineering 223, no 2 (22 avril 2009) : 97–100. http://dx.doi.org/10.1243/09544089jpme197.
Texte intégralRésumé :
The effect of distance between 90° elbow close to the upstream face of an orifice plate and the orifice plate on discharge coefficient was investigated. The distribution of discharge coefficient and differential pressure caused by elbow and short upstream straight length were examined and a modified discharge coefficient was introduced. The results presented in this study could be useful when the orifice plate is installed under the condition of simple flow disturbance element and short upstream straight length.
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Yang, Shanshan, Quanyuan Zeng, Xiaohua Zhang, Chunzhu Dong et Ling Guan. « Numerical Simulation of Single Droplet Impingement upon Dynamic Liquid Film Obliquely ». Mathematics 10, no 17 (4 septembre 2022) : 3193. http://dx.doi.org/10.3390/math10173193.
Texte intégralRésumé :
To better understand the application of droplet impingement in industry and agriculture, in this paper, the coupled level set and volume of fluid (CLSVOF) method is applied to study droplet oblique impact on a dynamic liquid film. The conclusions are the following: the downstream crown height increases and then decreases as the impact angle increases, whereas upstream crown height and spreading length decrease significantly; moreover, the spreading length and upstream crown height increase with the increase of film velocity, while the downstream crown height decreases instead. The increase of gas density inhibits both upstream and downstream crowns. When the fluid viscosity decreases or the impact velocity increases, the crown height increases significantly, which easily leads to crown rupture or droplet splash. The increase in impact velocity leads to an increase in spreading length; however, viscosity has almost no effect on the spreading length.
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Susanta, B., P. R. Suresh, K. Srinivasan et S. K. Das. « Effect of upstream developing length on the flow field of twin pipe jets ». Proceedings of the Institution of Mechanical Engineers, Part G : Journal of Aerospace Engineering 222, no 6 (juin 2008) : 773–82. http://dx.doi.org/10.1243/09544100jaero325.
Texte intégralThèses sur le sujet "UPSTREEM LENGHT"
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Clawson, Bradley C. « The Effects of Upstream Straight Pipe Length on Magnetic Flow Meter Accuracy ». DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5053.
Texte intégralRésumé :
In closed conduit water systems, being able to accurately measure flow is absolutely essential. For many meter designs, including electromagnetic induction meters (also known as magnetic flow meters), the greatest accuracy is achieved when the device is calibrated correctly. Optimal meter accuracy often depends on the flow conditions associated with the upstream geometry in the pipe system. Manufacturers typically give standards for the length of straight pipe required upstream of the meter. These standards vary, however, and do not address every possible configuration that may be installed upstream of the straight pipe requirement.
An investigation on the effects of the length of straight pipe between a single 90° elbow and the upstream side of magnetic flow meters was completed in this research. Eleven 10-inch meters were chosen for testing. The procedure included a baseline test with more than forty diameters of straight pipe between the elbow and the meter. The accuracy of the meter was determined over a range of flow velocities typical for operation of this type and size of meter. Further tests were performed with the meter installed only three diameters downstream of the elbow. These tests constitute Phase I. In Phase II, four meters were tested with the upstream pipe length varying from a close-coupled installation to ten diameters of straight pipe between the elbow and the meter to observe variances in accuracy with distance from the elbow.
The intent of the research was to show whether manufacturer accuracy specifications are achievable in actual application. It was determined that very few meters meet the manufacturer’s specification for accuracy even when installation requirements were met. Post-factory calibrations and minimization of velocity profile disruption through consideration of upstream geometry is recommended.
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ARYA, ADITYA. « SCOUR AROUND DIFFERENT SHAPES OF PIERS AT DIFFERENT ORIENTATION WITH FLOW ». Thesis, 2014. http://dspace.dtu.ac.in:8080/jspui/handle/repository/15500.
Texte intégralRésumé :
Scour is the process of local lowering of stream bed elevation which takes place in the vicinity or around a structure constructed in flowing water. Scour takes place around bridge piers, abutments, around spurs, jetties and breakwaters due to modification of flow pattern in such a way as to cause increase in local shear stress. Due to improper knowledge of scour around bridge pier, there were lots of bridges failure cases faces by our country which leads to economic loss and life loss. To understand the phenomenon of local scour around piers an attempt is done by experiment on different shape of bridge piers at different angle of attack of flow.
A series of experiments were performed to study the phenomenon of local scour that takes place beside a bridge pier of different shape on straight channel at different angle of attack, and to investigate the relation between the dimensions of the scour hole and between non-dimensional parameters describing the flow ratio, and angle of flow attack. All tests were held under clear-water condition, using a horizontal bed consisted of non-uniform sandy soil.
The experiments were conducted under different condition of flow parameters which helps to better understanding of local scour around different shapes of piers, and piers along the channel flow, across the channel flow and inclined to channel flow. The shape of scour hole, depth of scour, length of scour hole upstream and length of scour hole downstream helps in understanding geometry of scour hole and rate of scour in different cases of piers shape and orientation.
Under the different condition of flow, its helps to understanding the scour depth variation with time, with parts run of flow and with continuous flow run in a certain time. The others parameters like length of scour hole upstream and downstream to study the variation of geometry of scour hole.
With the different shape of piers, the pier having minimum scour is best for the design consideration for scour point of view, it also helps in designing of foundation as the increasing depth of foundation increase the cost of project with proper knowledge about scour phenomenon helps in designing cost effective piers.
Chapitres de livres sur le sujet "UPSTREEM LENGHT"
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Wang, Xiaodong, Jinchao Xu, Long Zhu, Donghui Zhou et Jun Zhao. « Study on the Unsteady Flow of the Approach Channel’s Entrance ». Dans Lecture Notes in Civil Engineering, 680–92. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_59.
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AbstractThe entrance of shiplock’s approach channel always exist a mixing shear layer caused by the shear mixing layer, where is the junction of main river flow and the quiescent water of the approach channel. The flow structure of the turbulent mixing area presented as large-scale vortices frequently and periodically. And the fluctuations of the water surface and velocity induced by the separation of vortices may threat the navigation conditions, which should be considered during the engineering designing. The existing studies regard the mixing shear layer as steady flow and only take care of the average shear velocity, which may underestimate the harm of the shear flow. In this work, RNG k-ε model and LES model were adoped to study the hydraulic characteristics of the entrance. The vortex characteristics and the influence on the water level and velocity were analyzed. Results shown that LES model had better precision than RNG k-ε model in the unsteady characteristics. Then further studies about the recirculation flow were performed with LES model, The length and period of the recirculation flow was studied. It found that the vortex was generated at the upstream of shear zone, and then transferred with the recirculate flow until it was collapsed. All the above provide references for hydraulic characteristics of the entrance.
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Chen, Yuyuan. « Study on the Movement Characteristics of Fire Smoke in V-Shaped Tunnel Under the Chimney Effect ». Dans Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220876.
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Analyze the force of fire smoke in a double-slope coupled V-shaped tunnel to study the influence of tunnel slope, the distance between the change slope point and the fire source on fire wind pressure, determine the basic characteristics of smoke movement, and use numerical simulation to spread the smoke authenticating. The results of the study show that when the smoke spreads to the left (upstream) of the slope change point of the tunnel, and with the increase of the slope, the temperature of the upstream top plate gradually decreases to the ambient temperature, and the smoke layer shows a parallel motion with the tunnel roof. When the tunnel slope reaches more than 10%, the roof temperature drops to the ambient temperature at 5m upstream; the upstream flow decreases with the slope. When the smoke is only in the tunnel to the right of the slope change point, the upstream smoke moves parallel to the horizontal plane. The slope is inversely related to the smoke backlash length, and when the slope is greater than 7%, the smoke backlash length is not sensitive to the change of fire source location.
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Zhou, Yiling, Hefang Jing, Weihong Wang et Qiutong Chen. « Experimental Study on Water Flow Characteristics in Open Channels with Floating Rigid Vegetation Groups ». Dans Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220961.
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To explore the water flow characteristics under the action of floating rigid vegetation groups, several laboratory tests are conducted in a flume of North Minzu University, in which floating rigid vegetation is replaced by glass rods. In the tests, two groups of vegetation are placed at different positions of the flume and the vegetation length into the water is changed. Experimental results show that both the upstream water level of the vegetation group and water surface slope along the way grow with the increasement of the length of the vegetation root. When vegetation root becomes longer, the flow velocity under the vegetation layer increases, while the flow velocity within the upper vegetation layer decreases. In addition, it can be also be found from the measured results that the turbulent kinetic energy of the flow increases as the length of the floating vegetation decreases in the water.
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Graf, William L. « Sediment and Plutonium Storage Upstream from Cochiti ». Dans Plutonium and the Rio Grande. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195089332.003.0014.
Texte intégralRésumé :
The foregoing chapters demonstrated that large amounts of sediment and much of the plutonium entering the Northern Rio Grande have been stored along the river channel. A composite budget analysis gives the quantities of materials involved annually, but except in very broad terms it does not describe where the materials are stored. It is a matter of scale: The budget indicates the overall quantities of sediment and plutonium stored in the system but does not reveal on a local scale where one might search for the materials. The next chapters show that the storage process has particular geographic characteristics and that in representative reaches it is possible to map those sediments that were deposited during the years of maximum input of plutonium into the system. These critical deposits are likely to contain more plutonium than are similar deposits of other years. In this way, the evidence of environmental change along the river provides a guide for determining the fate of plutonium in the system. A sampling program for assessing the storage of plutonium along the Northern Rio Grande depends on the development of the connections among vegetation communities, fluvial landforms, sedimentary deposits, and plutonium contents. Although it is not possible here to map and interpret completely the entire 313 km of river from Espanola to San Marcial, limited reaches can serve as representatives of larger portions of the whole. Eleven representative reaches, each about 3 to 6 km long, provide information on the entire study area because each representative reach exemplifies the conditions that obtain over a much larger portion of the total length of the river. My selection of the representative reaches began by reviewing the entire river by aerial photography and then directly in the field. The river divides itself into sections based on the geomorphologic conditions as modified by engineering works. Each representative reach illustrates the conditions within one larger section. For example, the Frijoles representative reach is similar to other relatively short reaches throughout White Rock Canyon.
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Bang, Joo Young, Il won Seo et Byeong Uk Kim. « Separation flow characteristics upstream of finite crest length weir with a downstream ramp ». Dans River Flow 2020, 175–77. CRC Press, 2020. http://dx.doi.org/10.1201/b22619-26.
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« Burbot : Ecology, Management, and Culture ». Dans Burbot : Ecology, Management, and Culture, sous la direction de Travis B. Horton et Adam C. Strainer. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781888569988.ch13.
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<em>Abstract.</em>—Although burbot <em>Lota lota </em>are native to Montana, little is known about their distribution, life history, and ecology. The objectives of this study were to determine the distribution, relative abundance, and population characteristics of burbot in the upper Missouri River basin in north-central Montana, and to compare sampling efficiency of hoop nets, cod traps, and slat traps. Hoop nets and cod traps were fished in the Missouri River during March 2005 and 2006, and slat traps were fished during March 2006. In total, hoop nets were fished 572 net nights, cod traps for 94 net nights, and slat traps for 92 net nights. Catch rates of hoop nets and cod traps were higher in 2005 than in 2006, and catch rates of all gear types were higher in the upstream half of the study area. Mean section-wide hoop-net catch rates exhibited a significant (<EM>P </EM>≤0.05) inverse relationship with increasing distance downstream from Holter Dam, while catch rates for other gear types did not. Catch rates were not significantly different (<EM>P </EM>≥0.05) among gear types. The size (length and weight) and condition (relative weight) of burbot sampled was significantly (<EM>P </EM>≤0.05) different among gear types. Length, weight, and relative weight were higher for burbot sampled in hoop nets and cod traps than those sampled in slat traps. Slat traps were effective at sampling small (≤300 mm) burbot. Although most (80%) burbot were recaptured within 10 km of where they were tagged, three burbot moved more than 33 km. We hypothesize that the distribution of burbot in our study reach has changed and relative abundance has increased due to the cumulative effect of upstream reservoirs (Canyon Ferry, Hauser, and Holter) by decreasing the downstream water temperature regimen.
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« Community Ecology of Stream Fishes : Concepts, Approaches, and Techniques ». Dans Community Ecology of Stream Fishes : Concepts, Approaches, and Techniques, sous la direction de Gary D. Grossma, Robert E. Ratajczak, Mark D. Farr, C. Michael Wagner et J. Todd Petty. American Fisheries Society, 2010. http://dx.doi.org/10.47886/9781934874141.ch4.
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<em>Abstract</em>.—Studies demonstrating the mechanisms regulating biodiversity are uncommon. Streams and rivers worldwide display a longitudinal gradient in fish biodiversity, and most prior research has used correlative evidence to infer that higher downstream diversity is produced by factors facilitating greater niche separation. We combine 20 years of fish abundance samples from a representative southern Appalachian stream with critical swimming velocity experiments to provide direct evidence that a shifting hydrodynamic barrier affects this gradient in Coweeta Creek. We observed increased diversity in multiple sites, produced by species immigrating upstream during periodic droughts (1985–1988, 1999–2002) and a highly significant positive relationship (<em>r<sup></em>2</sup> = 0.77) between drought (Palmer index) and Shannon-Weiner diversity. Resident fish generally had smaller standard lengths during drought periods. Critical velocity measurements showed that residents could tolerate faster water velocities than drought immigrants and that upstream velocities in nondrought years were faster than those in some downstream sites. These data support the hypothesis that local fish diversity in this system is limited by the ability of drought immigrants to pass an upstream hydrodynamic barrier. Alternative hypotheses such as temperature differences between sites, increased capture efficiency during droughts, and increased productivity during droughts were not supported by the data. The relationship between drought and diversity in this system is counterintuitive because drought should reduce resource availability and produce lower rather than higher diversity. These results highlight the important relationship between natural flow variation and maintenance of local diversity and demonstrate the need for long-term ecological data.
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McClain, Michael E., et Helmut Elsenbeer. « Terrestrial Inputs to Amazon Streams and Internal Biogeochemical Processing ». Dans The Biogeochemistry of the Amazon Basin. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195114317.003.0015.
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Enormous meandering rivers are the most remarkable fluvial feature of the Amazon landscape, but these rivers are only the largest component of a much denser network of streams which finely dissects and drains the basin. In terms of combined length and total amount of lotic habitat, streams dominate over their more visible downstream counterparts; this dominance is especially dramatic for first- and second-order streams which alone may account for greater than 80% of total channel length in meso-scale Amazon drainag basins. The flow of Amazon streams emerges directly from the extensive forests and savannas that compose the basin. Biogeochemical cycles in streams are thus intricately associated with processes operating in adjoining riparian and upland ecosystems. Terrestrial processes regulate the input of organic and inorganic species to stream systems, and the chemistry of inflowing waters determines, to some extent, the nature of subsequent reactions and even the composition of the stream’s biological community (Fittkau 1971). Undisturbed Amazon streams are thought to experience virtually no primary production (Walker 1995), thus most inputs of energy, as well as nutrients, must ultimately derive from terrestrial sources. This connection is particularly acute in first-order streams where there is no upstream input and all water, particulates, and solutes derive from immediately adjacent to the stream. Pathways linking the two systems include groundwater runoff, surface and subsurface storm runoff, wetland seepage, direct litterfall, and litter blow-in. These pathways are active across the entire Amazon basin, but their relative importance may vary regionally (McClain and Richey 1996, Elsenbeer and Lack 1996). Riparian ecosystems continue to influence the biogeochemistry of downstream reaches, but as streams become rivers upstream and in-channel influences become increasingly dominant. Streams and the corridors through which they flow also play a crucial role in regional-scale biogeochemical cycles. Greater than 90% of all terrestrial to lotic transfers in the Amazon basin occur in streams of order 6 and less. Thus, organic and inorganic species moving from terrestrial systems to large rivers and ultimately to the ocean must first pass through streams, where rates of material cycling and processing are rapid.
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« Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages ». Dans Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages, sous la direction de Brendan Martin, Yin-Phan Tsang, Ralph W. TingleyIII, Hannah Clilverd et Dana M. Infante. American Fisheries Society, 2019. http://dx.doi.org/10.47886/9781934874561.ch5.
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<i>Abstract.</i>—Waterfalls, caused by the abrupt changes of elevation in streams, are natural barriers that influence the distribution and dispersion of aquatic species. The resulting habitat fragmentation has contributed to species specialization as well as barriers that inhibit passage of nonnative species upstream. In Hawai‘i, it is assumed that nonnative species are unable to pass waterfall barriers, yet they are present above some waterfalls, possibly facilitated by human introduction. In this study, we used a landscape approach to identify likely human introductions and examine the ability of nonnative stream fauna to bypass waterfalls. We identified the human activities associated with the high likelihood of species introduction. We found that when a local catchment has a population density >4.24 people/km2 or road length density is >0.01 km/km2, the presence of nonnative species in the stream is likely a result of human introduction. After filtering human facilitated introduction, we also assessed the potential waterfall climbing ability of 14 nonnative taxa. We found that 12 out of the 14 taxa were absent upstream of waterfalls, indicative of their inability to traverse waterfalls. Only two species, Tahitian prawn (also known as monkey river shrimp) <i>Macrobrachium lar </i>and American bullfrog <i>Rana catesbiana</i>, seem able to pass waterfalls. This study highlights the role that people play in facilitating species introductions in otherwise inaccessible habitats. Without human interference, waterfalls can be considered effective barriers to nonnative species and can be instrumental in supporting nonnative species eradication and control strategies.
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Bauman, Adrian. « Obesity as a Public Health Problem ». Dans Oxford Textbook of Endocrinology and Diabetes 3e, sous la direction de John A. H. Wass, Wiebke Arlt et Robert K. Semple, 1815–20. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780198870197.003.0223.
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Public health approaches to obesity are distinctly different, but complementary, to clinical management. The history of describing obesity as a public health problem is lengthy, preceding the 1990s high-income country ‘obesity epidemic’. Overweight and obesity now affect half to two-thirds of developed country populations, and rates are still increasing in middle-income countries. Patterns and socioeconomic correlates of obesity differ across countries at different stages of industrial development. In relation to health outcomes, obesity is consistently related to non-communicable disease, especially diabetes. Risk increases across all levels of obesity, but increases exponentially for extreme obesity. Population-wide increases are likely due to a complex system of environmental, societal, economic, and cultural factors, and these need to be addressed in implementing upstream primary prevention solutions. Working outside of the health sector will be required, posing challenge to the implementation of national obesity prevention plans.
Actes de conférences sur le sujet "UPSTREEM LENGHT"
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Kim, Hong-Min, Kwang-Yong Kim, Jae-Young Her et Young-Chul Ha. « Three-Dimensional Flow Analysis for Estimation of Measuring Error of Orifice Flowmeter Due to Upstream Flow Distortion ». Dans ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31081.
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Three-dimensional pipe flows with elbows and tees are calculated to estimate the effect of upstream flow distortion on measuring accuracy of orifice flow meter. Axisymmetric flows through orifice are calculated first to evaluate the performances of various numerical schemes and turbulence models. In three-dimensional calculations of the flow in pipe system, it is evaluated how the pressure difference across the orifice is dependent on the length of upstream straight pipe in a branch. From the results, it is found that, regardless of flow rate, the effect of the length can be neglected for the lengths larger than thirty diameters although there still remain significant swirl at the orifice.
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He, Manman, Weining Liu, Yi Tang, Dihua Sun, Min Zhao, Qiliang Huang et Weiping Wang. « Prediction of Queue Length Considering Upstream Ramp Flow under Abnormal Events on Expressway ». Dans 21st COTA International Conference of Transportation Professionals. Reston, VA : American Society of Civil Engineers, 2021. http://dx.doi.org/10.1061/9780784483565.056.
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Lee, Sang-Youp, Jaesung Jang et Steve T. Wereley. « Entrance Length of Low Reynolds Number Flow in Microchannel ». Dans ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61908.
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The entrance lengths in rectangular microchannels with planar reservoirs, geometries typically produced with microfabrication techniques, have been investigated in the low Reynolds number range, 1 < ReD < 100. Two microchannels having the complementary aspect ratios (H/W) of 2.75 and 0.37 are fabricated and tested. The hydraulic diameters of two microchannels are ~370 μm and ~56.4 μm. μPIV is used to measure the velocity profiles and the entrance lengths are found from the curve fitted centerline velocity growth. The entrance lengths in the channels with planar upstream reservoirs are found to be significantly different from those with infinite upstream reservoirs.
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Pickett, Lyle M., et Dennis L. Siebers. « Orifice Diameter Effects on Diesel Fuel Jet Flame Structure ». Dans ASME 2001 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/2001-ice-399.
Texte intégralRésumé :
Abstract The effects of orifice diameter on several aspects of diesel fuel jet flame structure were investigated in a constant-volume combustion vessel under heavy-duty, direct-injection (DI) diesel engine conditions using Phillips research grade #2 diesel fuel and orifice diameters ranging from 45 μm to 180 μm. The overall flame structure was visualized with time-averaged OH chemiluminescence and soot luminosity images acquired during the quasi-steady portion of the diesel combustion event that occurs after the transient premixed burn is completed and the flame length is established. The lift-off length, defined as the farthest upstream location of high-temperature combustion, and the flame length were determined from the OH chemiluminescence images. In addition, relative changes in the amount of soot formed for various conditions were determined from the soot incandescence images. Combined with previous investigations of liquid-phase fuel penetration and spray development, the results show that air entrainment upstream of the lift-off length (relative to the amount of fuel injected) is very sensitive to orifice diameter. As orifice diameter decreases, the relative air entrainment upstream of the lift-off length increases significantly. The increased relative air entrainment results in a reduced overall average equivalence ratio in the fuel jet at the lift-off length and reduced soot luminosity downstream of the lift-off length. The reduced soot luminosity indicates that the amount of soot formed relative to the amount of fuel injected decreases with orifice diameter. The flame lengths determined from the images agree well with gas jet theory for momentum-driven, non-premixed turbulent flames.
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« Numerical Investigation of the Recirculation Zone Length Upstream of the Round-Nosed Broad Crested Weir ». Dans Sept. 8-10, 2017 Istanbul (Turkey). URST, 2017. http://dx.doi.org/10.17758/urst.u0917303.
Texte intégral
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Peng, Yuhua, et Guangyu Chen. « Study on the Length of Upstream Transition Section in Reconstruction and Expansion Area of Secondary Highway ». Dans 21st COTA International Conference of Transportation Professionals. Reston, VA : American Society of Civil Engineers, 2021. http://dx.doi.org/10.1061/9780784483565.129.
Texte intégral
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Lee, Jang Il, Ae Ju Cheong et Bok Ki Min. « A Numerical Study on Flow Characteristics Through Orifice Flowmeter and Measurement Accuracy Depending on Upstream Straight Length ». Dans ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69033.
Texte intégralRésumé :
In this numerical study, Commercial CFD (Computational Fluid Dynamics) code, ANSYS CFX ver. 17.1, is used to analyze the 3-Dimensional flow characteristics through orifice plate (β = 0.6) with two 90 degree bends in different planes. The purpose of this numerical study is to evaluate measurement accuracy and flow characteristics of orifice flowmeter depending on upstream straight length from 12D to 56D. Thus, numerical calculations of pressure drop caused by swirling flow and distortion of axial velocity profile on orifice plate are performed by using numerical analysis. In addition, numerical analysis results are compared with recommended upstream straight length of ASME Performance Test Codes 19.5 for orifice plates and nozzles. The results show that if upstream straight length of orifice flowmeter is more than 40D, there is a little deviation of differential pressure. Moreover, it is found that up-down asymmetry of recirculation zones is relatively attenuated as the upstream straight length increases.
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Iga, Yuka, Hayato Nishitanaka et Yoshida Yoshiki. « Numerical Analysis of Influence of Pipe Length on Cavitation Surge ». Dans ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-06066.
Texte intégralRésumé :
Generally, in boundary condition of numerical simulation of internal flow, flow velocity is fixed in the inlet boundary and static pressure is fixed in the outlet boundary or the inverse condition, which is supposed that upstream and downstream pipes and the uniform flows inside the pipes extend infinitely from the boundaries. Therefore, a numerical simulation of influence of pipe length of fluid machinery cannot be realized by changing a boundary position of the computational region. In the present study, a boundary condition which is taking into account a pipe length is used to numerical simulation of unsteady cavitation in three-blade cyclic cascade, where generalized unsteady Bernoulli equation is adapted to one dimensional region from a upstream tank to the inlet boundary. In the study, cavitation surge frequencies reproduced in the present study are compared with empirical and theoretical characteristics of cavitation surge frequencies. Then, it shows good agreement with empirical frequency of cavitation surge although it does not take into account of the system such as pipe length. On the other hand, the theoretical frequency, which takes into account of the system, predicts a value which is less than half of the present numerical result.
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Luk, K. F., R. M. C. So, S. C. Kot, Y. L. Lau et R. C. K. Leung. « Airfoil Vibration Due to Upstream Alternating Vortices Generated by a Circular Cylinder ». Dans ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33011.
Texte intégralRésumé :
An experimental investigation of airfoil vibration due to upstream alternating vortices was carried out in a re-circulating wind tunnel. A circular cylinder with a diameter D = 102mm was positioned upstream of an airfoil (NACA0012), with a chord length c = 200mm and a zero angle of attack placed at a gap distance S, to generate the vortex street. The circular cylinder and airfoil were arranged in tandem and the spacing ratio S/D was varied from 0.5 to 6.5 to investigate the effect of the vortices generated upstream on the vibration of the airfoil. The experiment was carried out in a free stream Re range of 1.6×105 to 2.3×105. The vortex formation region behind a single circular cylinder was measured using a hot wire anemometer and the airfoil dynamic responses were examined using a laser vibrometer. It is found that when S/D is reduced beyond a critical value, there is a rapid drop in vortex shedding frequency and a suppression in airfoil vibration. This critical S/D is found to be the normalized length of the vortex formation region behind the single cylinder. It is hypothesized that the vortex could not be formed at this location within the gap distance in the presence of the airfoil, but instead is formed behind the airfoil. Consequently, as vortex shedding is switched from upstream to downstream of the airfoil, the flow-induced vibration of the airfoil is suppressed at the same time.
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Coulthard, Sarah M., Ralph J. Volino et Karen A. Flack. « Effect of Unheated Starting Lengths on Film Cooling Experiments ». Dans ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72392.
Texte intégralRésumé :
The effect of an unheated starting length upstream of a row of film cooling holes was studied experimentally to determine its effect on heat transfer coefficients downstream of the holes. Cases with a single row of cylindrical film cooling holes inclined at 35 degrees to the surface of a flat plate were considered at blowing ratios of 0.25, 0.5, 1.0 and 1.5. For each case experiments were conducted to determine the film cooling effectiveness and the Stanton number distributions in cases with the surface upstream of the holes heated and unheated. Measurements were made using an infrared camera, thermocouples, and hot and cold wire anemometry. Ratios were computed of the Stanton number with film cooling (Stf) to corresponding Stanton numbers in cases without film cooling (Sto) but the same surface heating conditions. Contours of these ratios were qualitatively the same regardless of the upstream heating conditions, but the ratios were larger for the cases with a heating starting length. Differences were most pronounced just downstream of the holes and for the lower blowing rate cases. Even 12 diameters downstream of the holes the Stanton number ratios were 10 to 15% higher with a heated starting length. The differences in Stanton number distributions are related to jet flow structures which vary with blowing rate.
Rapports d'organisations sur le sujet "UPSTREEM LENGHT"
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Friedman, Haya, Julia Vrebalov, James Giovannoni et Edna Pesis. Unravelling the Mode of Action of Ripening-Specific MADS-box Genes for Development of Tools to Improve Banana Fruit Shelf-life and Quality. United States Department of Agriculture, janvier 2010. http://dx.doi.org/10.32747/2010.7592116.bard.
Texte intégralRésumé :
Fruit deterioration is a consequence of a genetically-determined fruit ripening and senescence programs, in which developmental factors lead to a climacteric rise of ethylene production in ethylene-sensitive fruits such as tomato and banana. Breeding of tomato with extended fruit shelf life involves the incorporation of a mutation in RIN, a MADS-box transcription factor participating in developmental control signalling of ripening. The RIN mode of action is not fully understood, and it may be predicted to interact with other MADS-box genes to execute its effects. The overall goal of this study was to demonstrate conservation of ripening control functions between banana and tomato and thus, the potential to genetically extend shelf-life in banana based on tools developed in tomato. The specific objectives were: 1. To increase the collection of potential RIN-like genes from banana; 2. To verify their action as developmental regulators; 3. To elucidate MADS-box gene mode of action in ripening control; 4. To create transgenic banana plants that express low levels of endogenous Le-RIN- like, MaMADS- gene(s). We have conducted experiments in banana as well as in tomato. In tomato we have carried out the transformation of the tomato rin mutant with the MaMADS1 and MaMADS2 banana genes. We have also developed a number of domain swap constructs to functionally examine the ripening-specific aspects of the RIN gene. Our results show the RIN-C terminal region is essential for the gene to function in the ripening signalling pathway. We have further explored the tomato genome databases and recovered an additional MADS-box gene necessary for fruit ripening. This gene has been previously termed TAGL1 but has not been functionally characterized in transgenic plants. TAGL1 is induced during ripening and we have shown via RNAi repression that it is necessary for both fleshy fruit expansion and subsequent ripening. In banana we have cloned the full length of six MaMADS box genes from banana and determined their spatial and temporal expression patterns. We have created antibodies to MaMADS2 and initiated ChI assay. We have created four types of transgenic banana plants designed to reduce the levels of two of the MaMADS box genes. Our results show that the MaMADS-box genes expression in banana is dynamically changing after harvest and most of them are induced at the onset of the climacteric peak. Most likely, different MaMADS box genes are active in the pulp and peel and they are differently affected by ethylene. Only the MaMADS2 box gene expression is not affected by ethylene indicating that this gene might act upstream to the ethylene response pathway. The complementation analysis in tomato revealed that neither MaMADS1 nor MaMADS2 complement the rin mutation suggesting that they have functionally diverged sufficiently to not be able to interact in the context of the tomato ripening regulatory machinery. The developmental signalling pathways controlling ripening in banana and tomato are not identical and/or have diverged through evolution. Nevertheless, at least the genes MaMADS1 and MaMADS2 constitute part of the developmental control of ripening in banana, since transgenic banana plants with reduced levels of these genes are delayed in ripening. The detailed effect on peel and pulp, of these transgenic plants is underway. So far, these transgenic bananas can respond to exogenous ethylene, and they seem to ripen normally. The response to ethylene suggest that in banana the developmental pathway of ripening is different than that in tomato, because rin tomatoes do not ripen in response to exogenous ethylene, although they harbor the ethylene response capability This study has a major contribution both in scientific and agricultural aspects. Scientifically, it establishes the role of MaMADS box genes in a different crop-the banana. The developmental ripening pathway in banana is similar, but yet different from that of the model plant tomato and one of the major differences is related to ethylene effect on this pathway in banana. In addition, we have shown that different components of the MaMADS-box genes are employed in peel and pulp. The transgenic banana plants created can help to further study the ripening control in banana. An important and practical outcome of this project is that we have created several banana transgenic plants with fruit of extended shelf life. These bananas clearly demonstrate the potential of MaMADS gene control for extending shelf-life, enhancing fruit quality, increasing yield in export systems and for improving food security in areas where Musaspecies are staple food crops.