Vertical slot fish pass

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Contribution of experimental fluid mechanics to the design of vertical slot fish passes

Contribution of experimental fluid mechanics to the design of vertical slot fish passes

This paper presents the main results of an experimental study of mean and turbulent characteristics of flow in a scale model of a vertical slot fish pass with varying width and slope (from 5% to 15%). Experimental hydraulic modelling was combined with the study of fish behaviour in the model. The discharge coefficient, which significantly affects the design of such facilities, varied from 0.67 to 0.89 and was strongly influenced by the slope. Two distinct flow patterns were observed, depending on the slope and the fish pass width. The point of transition between the two states was determined. Low velocity areas are likely resting zones for fish and particular attention was paid to evaluating these areas. Slope was found to affect both the volume of the low velocity zone, and the value of turbulent kinetic energy in these areas. The statistical characteristics of turbulent kinetic energy in the pools were linked primarily to the maximum velocity in the jet. An analysis of the behaviour of juvenile brown trout (Salmo trutta) in the scale model clearly showed that the fish avoided the areas of high velocities in the jet, except at the slot itself where they took advantage of the jet’s non-stationary character. Low-velocity areas were not frequented uniformly by fish, which stayed most frequently in the zone located just downstream from the slot and behind the small side baffle. It is suggested that future studies might investigate lower pool-length to slot-width ratios, which might make it possible to increase the slope significantly and should also examine ways of improving hydraulic conditions for fish by carefully distributing obstacles in pools.
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An experimental study of turbulent flow in vertical slot fishways

An experimental study of turbulent flow in vertical slot fishways

ABSTRACT The vertical slot fishways are hydraulic structures that allow the upstream migration of fishes through engineering constructions or natural obstructions in rivers. This type of pool fish pass is generally very effective in ensuring passage of the target species, particularly diadromous species. However, visual observations have shown that certain small species may be trapped in the large recirculation zones and seem to have difficulty in rapidly passing through very large pools. An experimental study was undertaken to characterize the turbulent flow for various configurations of vertical slot fishways and to determine how their characteristics might be modified in order to facilitate the passage of small species. The characteristics of mean flow and turbulence were studied by PIV and visualizations for several different slopes, flow discharges and pool widths. The results showed that the flow pattern always takes one of two topology models depending on the ratio length/width of the pool. In order to study the extent to which the dimensions of recirculation zones can be reduced, the effect of the insertion of vertical cylinders within the pools was visualized.
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Topologies and measurements of turbulent flow in vertical slot fishways

Topologies and measurements of turbulent flow in vertical slot fishways

Abstract Several vertical slot fishways have been built in France over the last 20 years. This type of pool fish pass is generally very effective in ensuring passage of the target species, particularly diadromous species. However, visual observations have shown that certain small species may be trapped in the large recirculation zones and seem to have difficulty in rapidly passing through very large pools. An experimental study was undertaken to characterize the turbulent flow for various configurations of vertical slot fishways and to determine how they might be modified to facilitate the passage of small species. The characteristics of mean flow and turbulence were studied by particle image velocimetry (PIV) for three slopes (I = 5%, 10%, 15%), three flow discharges (Q = 576, 736, 864 L/s) and four pool widths (B = 1.7, 2, 2.3, 2.7 m). The results showed that the flow pattern always follows one of two topological models depending on the length/
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Effects of various configurations of vertical slot fishways on fish behaviour in an experimental flume

Effects of various configurations of vertical slot fishways on fish behaviour in an experimental flume

1 INTRODUCTION In an attempt to restore the connectivity of fragmented river habitat which is very important to achieve ecological status in relation to the EU Water Framework Directive, a variety of passage facilities have been installed at river barriers. Vertical slot fishways (VSFs) is one of this device used to facilitate fish passage through dams particularly diadromous species. However, the small cyprinids are rarely considered like target species and the efficiency of fish pass are rarely documented to produce improvement of fishways. A detailed knowledge of flows within these hydraulic structures and the interactions between fishes and turbulence characteristics are vital for successful passage through a fishway ([6], [7] and [10]).
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An experimental study of turbulent flow in vertical slot fishways

An experimental study of turbulent flow in vertical slot fishways

ABSTRACT The vertical slot fishways are hydraulic structures that allow the upstream migration of fishes through engineering constructions or natural obstructions in rivers. This type of pool fish pass is generally very effective in ensuring passage of the target species, particularly diadromous species. However, visual observations have shown that certain small species may be trapped in the large recirculation zones and seem to have difficulty in rapidly passing through very large pools. An experimental study was undertaken to characterize the turbulent flow for various configurations of vertical slot fishways and to determine how their characteristics might be modified in order to facilitate the passage of small species. The characteristics of mean flow and turbulence were studied by PIV and visualizations for several different slopes, flow discharges and pool widths. The results showed that the flow pattern always takes one of two topology models depending on the ratio length/width of the pool. In order to study the extent to which the dimensions of recirculation zones can be reduced, the effect of the insertion of vertical cylinders within the pools was visualized.
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Detailed experimental study of hydrodynamic turbulent flows generated in vertical slot fishways

Detailed experimental study of hydrodynamic turbulent flows generated in vertical slot fishways

2 Experimental setup and postprocessing tools 2.1 Experimental device For this experimental study the geometry of the physical model used was based on an analysis of the geometry of VSFs built in France over the last 20 years, from which we defined an ‘average’ geometry. The fishway model conceived in the P’ Institute Laboratory was built at the largest possible geometrical scale to be able to carry out observations on the fish behav- iour in the future. The model was made of five pools, L = 0.75 m long and H = 0.55 m deep, installed in a plexiglass flume (Fig. 1 ). The width of the slot was b = 0.075 m. Four different values of B, the pool width, have been tested: B = 0.675, 0.575, 0.50 and 0.425 m (B/b = 9– 5.67). The baffles in the pools had the following dimensions: A = 0.15 m ( A/b = 2), a = 0.1 m (a/b = 1.3) with “ A” being the length of the large central deflector and “a” being the length of the small side deflector. The model and the prototype were related by the Froude similitude, on a geometrical scale between 1/2.5 (for a small trout fish pass) and approximately 1/6 (for a large fish pass for shad and large diadromous species) depending on the dimensions of the prototype pools.
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Filtering slot antenna using coupled line resonator

Filtering slot antenna using coupled line resonator

erwan.fourn@insa-rennes.fr Abstract—This paper presents the design of a novel slot filter- ing antenna suitable for modern electronic devices integrating various wireless systems that have to coexist. The approach consists in feeding the slot antenna through a filtering microstrip- to-slot-line transition. This transition comprises a coupled line resonator which enables to create two out-of-band transmission zeros and by this way to increase drastically the frequency selectivity of the transition. As proof-of-concept, a slot filtering antenna has been designed for WLAN applications operating in the 2.4GHz band, by using the HFSS TM simulation tool.
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A mountain pass for reacting molecules

A mountain pass for reacting molecules

We then restrict our study to a simplified (but still relevant) model: a molecule made of two interacting parts, the geometry of each part being frozen. We show that this lack of compactness is impossible under some natural assumptions about the configurations ”at infinity”, proving the existence of the mountain pass in these cases. More precisely, we suppose either that the molecules at infinity are charged, or that they are neutral but with dipoles at their ground state.

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Accès aux soins des mineurs non accompagnés en France : proposition d'amélioration retenues par les coordinateurs de PASS Régionaux après enquêtes auprès des équipes PASS

Accès aux soins des mineurs non accompagnés en France : proposition d'amélioration retenues par les coordinateurs de PASS Régionaux après enquêtes auprès des équipes PASS

Le sujet des MNA est régulièrement abordé par les médias (21, 22) et les associations qui dénoncent un retard dans la mise en place des dispositifs des conseils départementaux. Des études épidémiologiques ont été effectuées sur la population des MNA, la grande majorité traitant des pathologies psychiatriques secondaires à leur parcours de vie et de migrants. (23-26). Quelques travaux français ont étudié la santé des mineurs migrants consultant dans les PASS (27, 28). Aux Pays Bas, une étude de 2018 énumère les difficultés de prise en charge médicale par les pédiatres confrontés à cette population (29).
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Electronic architectures of optical slot switching nodes

Electronic architectures of optical slot switching nodes

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignemen[r]

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Flexible Issue Slot Assignment for VLIW Architectures

Flexible Issue Slot Assignment for VLIW Architectures

Unit´e de recherche INRIA Lorraine, Technopˆole de Nancy-Brabois, Campus scientifique, ` NANCY 615 rue du Jardin Botanique, BP 101, 54600 VILLERS LES Unit´e de recherche INRIA Rennes, Ir[r]

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How to handle frozen fish.  Hints on frozen fish

How to handle frozen fish. Hints on frozen fish

Frozen Fish Retain Best Elements.-Accurate investigations bty experts prove that there is no important difference between frozen fish and fresh fish of the same s[r]

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Microwave linear array of slot radiators

Microwave linear array of slot radiators

Microwave linear array of slot radiators National Research Council of Canada, Radio Branch https://publications-cnrc.canada.ca/fra/droits L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

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Equidispersive Dual-Mode Long Slot Arrays

Equidispersive Dual-Mode Long Slot Arrays

analytic calculation was also validated using the full-wave simulator [15]. V. Q UASI E QUI - DISPERSIVE O PEN -E NDED S TUBS As a difference with [5], open-ended ED PPWs radiate two orthogonally-oriented modes, whose frequency dispersion is the same. The unit cell of the CTS array is shown in Figs. 6(a) and (b) for TM and TE modes, respectively. Periodic boundary conditions are enforced on lateral faces along x-axis. Also, perfect magnetic (PMC) and electric (PEC) boundary conditions are alternately considered along y-axis for optimal operation of TM and TE modes, respectively. The long-slot array is designed to operate at Ka-band. The width of the slot is a = λ min /2, where λ min is the wavelength at 35 GHz.
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Metal-Only Transmitarray Based on C-Shaped Slot

Metal-Only Transmitarray Based on C-Shaped Slot

Fig. 4. Simulated co-polarized gain components of the MOTA at 19 GHz. IV. C ONCLUSIONS AND P ERSPECTIVES Metal-only unit-cells and transmitarrays have been introduced for very low cost applications, particularly for Satcom ground terminals at down-link band. The corresponding unit-cells are based on pass-band C-shaped frequency selective surfaces. Fabrication of the prototypes is under progress and detailed experimental results will be presented during the conference (fabrication techniques, assembly, and performance in radiation). The proposed concept can be scaled for other applications (e.g., up-link Satcom in Ka-band, outdoor flat antenna panels for 5G access points and backhaul links in Ka-band and V-band).
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Détermination de critères d'évaluation des PASS avec les usagers du dispositif : un travail avec des patients consultant dans les PASS des centres hospitaliers de Grenoble et Chambéry

Détermination de critères d'évaluation des PASS avec les usagers du dispositif : un travail avec des patients consultant dans les PASS des centres hospitaliers de Grenoble et Chambéry

A : je comprends services avec un s (tous d’accord). P4 : Moi je viens du Congo Kinshasa (comparaison par rapport au pays) où l’aide à un malade à l’hôpital n’est pas organisé comme ici. Quand au début je suis arrivé, je suis tombé gravement malade le jour où j’ai rencontré [nom de l’infirmière de la PASS cité]. Je suis vraiment tombé malade parce que j’avais une déprime psychologique. (Décrit les conditions de son hébergement les premiers jours au secours catholique puis à l’accueil de jour pendant l’hiver, mauvais souvenirs, n’avait pas dormi, ils étaient très nombreux dans une salle un peu insalubre, …) J’ai eu tellement mal à la tête, je suis hypertendu. Avec toutes les réflexions pleins la tête, le matin j’étais vraiment malade. Je savais bien que je ne pouvais accéder aux soins, car sur moi je n’avais aucun papier. Chez nous, vous êtes malade vous allez à l’hôpital. Si vous n’avez pas d’argent vous ne pouvez pas accéder aux soins, ça n’existe pas. Ils regardent d’abord l’argent. L’aspect service est nul. Même au niveau du service médical, les infirmières, elles peuvent être là, elles verront d’abord l’administration, c'est-à-dire l’enregistrement, le paiement des frais. L’aspect service gratuité n’existe pas. Etre à la disposition de pour écouter ça n’existe presque pas. Apres j’ai rencontré [nom de l’infirmière de la PASS cité] qui m’a dit que je pouvais consulter à 14h. Je suis revenu, je lui ai expliqué ce qui n’allait pas, elle m’a donné un doliprane en attendant de voir le médecin. Ce qui m’a frappé aussi, un autre service, c’est que le médecin ne me demande pas si j’ai payé ou pas, il vous demande rien, il se met à votre disposition pour que vous lui disiez quels sont vos problèmes. Et c’est l’aspect du temps qu’il a mis à m’écouter, qui a fait à un moment donné que les maux de tête ont même réussi à un peu s’évanouir. Il m’a écouté pendant longtemps, ce qui n’existe pas au Congo. Sans tenir compte de votre qualité. Après
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Végétal - Vertical

Végétal - Vertical

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignemen[r]

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Original Theory of NGD Low Pass-High Pass Composite Function for Designing Inductorless BP NGD Lumped Circuit

Original Theory of NGD Low Pass-High Pass Composite Function for Designing Inductorless BP NGD Lumped Circuit

ABSTRACT This paper aims to develop an original circuit theory of inductorless NGD topology. The considered passive cell comprised of resistor and capacitor elements without inductor operates as a bandpass (BP) NGD function. The specifications of NGD functions are defined. Generally, the BP NGD fully lumped circuits available in the literature operate with resonant RLC-network. In the introduced research work, a lumped circuit was first time identified to exhibit the BP behavior without the presence of inductive component. The inductorless BP NGD topology is inspired from the combination of low-pass (LP) and high-pass (HP) NGD passive cells. Therefore, an original LP-HP NGD composite topology is obtained. The identified BP NGD topology is constituted only by passive RC-networks. Then, theoretical development of BP NGD analysis is explored. The inductorless circuit theory starts with the identification of BP NGD canonical form. Then, the expressions of NGD value, center frequency and attenuation in function of RC-network parameters are established. The synthesis equations allowing to determine the resistor and capacitor elements are derived. Proofs-of-concept are designed and prototypes are fabricated to verify the effectiveness of the developed LP-HP NGD composite theory. To validate the developed original circuit theory, two prototypes of RC-network based LP-HP NGD composite were designed, fabricated, simulated and tested. The two prototypes were synthesized with respect to two different NGD center frequencies 13.5 MHz and 22 MHz. As expected, the calculated, simulated and measurement results are in very good agreement with NGD value of about some negative nanoseconds. In the future, the characterized inductorless topology enable to overcome the traditional limitations of RLC-network based BP NGD circuits because of inductance self-effect limitation.
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Dans mon silence vertical

Dans mon silence vertical

Parce ce que les images sont placées entre d’autres images provenant d’un lieu différent, et appartiennent à une autre histoire, elles agissent alors comme ce qu’elles sont en réalité [r]

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Which fish should I eat? Perspectives influencing fish consumption choices.

Which fish should I eat? Perspectives influencing fish consumption choices.

life stage, and reliance on fish intake because of subsistence needs or cultural traditions. Based on evidence we present here, fish consumption advice addressed to the general public should be clear and simple to have an impact. We suggest developing a list of fish to eat, and those to minimize or avoid, that considers these multiple perspectives and not solely the health effects of contaminants and nutrients. This list should include links to more detailed resources that can be used by those wanting more information about individual fish types or wishing to optimize one or more parameters. The simple message needs to be provided on a national level but with the cooperation of local and regional partners (e.g., states and nongovernmental organizations). Thus, adjustments could be made on a regional level if necessary, as long as the framework can be followed. As further information becomes available, the list of beneficial choices, as well as choices to avoid, could be improved upon. Although simplicity of messaging is paramount, the underlying paradigm addressing the challenges presented in Table 3 would not be simple. Yet with transparency, an approach on a national level could be developed that
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