USBR Type III and Type IV Stilling Basins and Rock Aprons Associated with Stepped Chutes

2018 ◽  
Vol 34 (2) ◽  
pp. 389-394
Author(s):  
Sherry L. Hunt ◽  
Kem C. Kadavy
Keyword(s):  
Research Unit ◽  
Stepped Spillways ◽  
Engineering Research ◽  
Bureau Of Reclamation ◽  
Stilling Basin ◽  
Type Iii ◽  
Design Engineers ◽  
Type Iv ◽  
Rock Stability ◽  
Stilling Basins

Abstract. Stilling basins are commonly used as energy dissipators for structural chutes. Classical research conducted by scientists of the U. S. Bureau of Reclamation (USBR) led to the development of design criteria for a variety of stilling basin configurations as the outlet works for smooth chutes, but little is known about the performance of these dissipators when paired with stepped chutes. Research at the USDA-ARS Hydraulic Engineering Research Unit (HERU) in Stillwater, Oklahoma, was conducted on USBR Type III and Type IV stilling basins with rock aprons located downstream of a near prototype stepped chute. Data indicates Froude numbers based on the incoming clear water flow depth to the stilling basin range from 3.3 = F = 5.5. Visual observations noted during the tests indicate acceptable performance of the Type III and Type IV stilling basins when operated at recommended or greater tailwater settings as set forth by the USBR. Three methods, the Isbash, USBR, and USGS, were chosen for evaluating the rock stability of the rock aprons placed downstream of the endsill of the stilling basins used in association with stepped chutes. Data indicate each method is suitable for riprap sizing of the rock apron. The intent of this research is to provide design engineers with knowledge regarding the performance of USBR Type III and Type IV stilling basins with rock aprons designed in conjunction with stepped chutes. Keywords: Dam safety, Embankment dams, Energy dissipation, Rock apron, Roller compacted concrete, Stepped spillways, Stilling basin.

scholarly journals Analysis of the Flow in a Typified USBR II Stilling Basin through a Numerical and Physical Modeling Approach

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 227 ◽  
Author(s):  
Juan Francisco Macián-Pérez ◽  
Rafael García-Bartual ◽  
Boris Huber ◽  
Arnau Bayon ◽  
Francisco José Vallés-Morán
Keyword(s):  
Physical Model ◽  
Hydraulic Jump ◽  
Numerical Approach ◽  
Free Surface Flows ◽  
United States Bureau ◽  
Bureau Of Reclamation ◽  
Stilling Basin ◽  
Modeling Approach ◽  
Stilling Basins ◽  
Energy Dissipation Devices

Adaptation of stilling basins to higher discharges than those considered for their design implies deep knowledge of the flow developed in these structures. To this end, the hydraulic jump occurring in a typified United States Bureau of Reclamation Type II (USBR II) stilling basin was analyzed using a numerical and experimental modeling approach. A reduced-scale physical model to conduct an experimental campaign was built and a numerical computational fluid dynamics (CFD) model was prepared to carry out the corresponding simulations. Both models were able to successfully reproduce the case study in terms of hydraulic jump shape, velocity profiles, and pressure distributions. The analysis revealed not only similarities to the flow in classical hydraulic jumps but also the influence of the energy dissipation devices existing in the stilling basin, all in good agreement with bibliographical information, despite some slight differences. Furthermore, the void fraction distribution was analyzed, showing satisfactory performance of the physical model, although the numerical approach presented some limitations to adequately represent the flow aeration mechanisms, which are discussed herein. Overall, the presented modeling approach can be considered as a useful tool to address the analysis of free surface flows occurring in stilling basins.

Radial flow stilling basins with baffle blocks

1989 ◽  
Vol 16 (4) ◽  
pp. 489-497 ◽  
Author(s):  
Peter C. Nettleton ◽  
John A. McCorquodale
Keyword(s):  
Key Words ◽  
Hydraulic Jump ◽  
Water Surface ◽  
Radial Flow ◽  
Surface Profile ◽  
Hydraulic Jumps ◽  
Bureau Of Reclamation ◽  
Stilling Basin ◽  
Jump Length ◽  
Stilling Basins

A total of 120 tests of forced radial flow hydraulic jumps have been analyzed in order to develop curves and equations for the design of radial stilling basins. The jump depth, the water surface profile, wave amplitudes, the allowable flare angle, and the jump length are defined in terms of entrance conditions, the baffle position, and the baffle height. An example design is given and compared with a USBR (U.S. Bureau of Reclamation) Type III stilling basin. Key words: forced hydraulic jump, radial flow, design, stilling basins, baffles, radial hydraulic jump, circular hydraulic jump.

scholarly journals History of stepped channels and spillways: a rediscovery of the “wheel”

1995 ◽  
Vol 22 (2) ◽  
pp. 247-259 ◽  
Author(s):  
H. Chanson
Keyword(s):  
Energy Dissipation ◽  
Key Words ◽  
Mediterranean Sea ◽  
Irrigation System ◽  
Stepped Spillways ◽  
Stilling Basin ◽  
Design Engineers ◽  
Irrigation Channels ◽  
History Of ◽  
The Mediterranean

Recently, spillways with a stepped profile have regained interest and favor among design engineers to pass flood waters over the dams. The stepped geometry enhances the energy dissipation above the spillway and reduces the size of a downstream stilling basin. In this paper, the author shows that the technique of stepped channels has been developed since Antiquity. Spillways and irrigation channels with stepped profiles were developed by several civilisations around the Mediterranean sea and in America. The main characteristics of the stepped spillways along the ages suggest a regular evolution rather than a revolution. Present stepped spillways are designed to pass similar discharges as 200 years ago. Key words: stepped channels, spillway, irrigation system, history, design techniques, energy dissipation.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

scholarly journals Outcomes of one-stage reconstruction for chronic multiligament injuries of knee

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Tarun Goyal ◽  
Souvik Paul ◽  
Sushovan Banerjee ◽  
Lakshmana Das
Keyword(s):  
Cruciate Ligament ◽  
Lysholm Score ◽  
Activity Level ◽  
Type Ii ◽  
Hamstring Tendons ◽  
Peroneus Longus ◽  
Type Iii ◽  
Type Iv ◽  
Ikdc Score

Abstract Purpose This article aims to evaluate patterns of chronic multiligament injuries and outcomes of treatment with single-stage reconstruction using autografts. Methods All patients with clinicoradiologically diagnosed multiligament knee injury (MKI) were included in this prospective observational study. As the time since injury was more than 6 weeks in all of the patients, they were categorized as having chronic MKI. Patients were assessed clinically for laxity, and the diagnosis was confirmed radiologically. Ipsilateral hamstring tendons were used for medial collateral ligament (MCL) or posterolateral corner reconstruction in a patient with Schenck knee dislocation (KD) type III. In these cases, the posterior cruciate ligament (PCL) and anterior cruciate ligament (ACL) were reconstructed by using the peroneus longus and contralateral hamstring tendons respectively. Ipsilateral hamstring tendons were used for ACL reconstruction and an ipsilateral peroneus longus tendon graft was used for reconstruction of the PCL in a KD type II injury. In two cases of KD type IV injury, the lateral laxity was only grade II and was managed conservatively; the rest of the ligaments were addressed like a KD type III injury. Outcome evaluation was done using a visual analogue scale (VAS) for pain, International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity level, preoperatively and postoperatively at 2 years’ follow-up. Results A total of 27 patients of mean age 33.48 ± 9.9 years with MKI were included in the study. The patients were classified as eight KD type II, 17 KD type III, and two KD type IV. The majority of the patients had associated meniscal (59.2%) or chondral (40.7%) injuries. At the 2 years’ follow-up visit, there were significant improvements in VAS score (p = 0.0001) IKDC score (p = 0.0001), Lysholm score (p = 0.0001), and range of motion (p = 0.001). None of the patients had residual laxity on clinical examination of the knee joint at the 2 years’ follow-up. All but two of the patients went back to their previous activity level. These two patients had progressive knee arthritis and needed knee arthroplasty. Conclusion Single-stage surgical reconstruction for chronic MKI has favourable functional outcomes. Level of evidence Level IV, case series.

scholarly journals Brachial supporting structure of Spiriferida (Brachiopoda)

2020 ◽  
pp. 1-15
Author(s):  
Zhiwei Yuan ◽  
Wen Guo ◽  
Dan Lyu ◽  
Yuanlin Sun
Keyword(s):  
Mantle Cavity ◽  
Family Type ◽  
Type I ◽  
Type Ii ◽  
Feeding Apparatus ◽  
Single Family ◽  
Supporting Structure ◽  
Type Iii ◽  
Type Iv ◽  
Evolutionary Lineages

Abstract The filter-feeding organ of some extinct brachiopods is supported by a skeletal apparatus called the brachidium. Although relatively well studied in Atrypida and Athyridida, the brachidial morphology is usually neglected in Spiriferida. To investigate the variations of brachidial morphology in Spiriferida, 65 species belonging to eight superfamilies were analyzed. Based on the presence/absence of the jugal processes and normal/modified primary lamellae of the spiralia, four types of brachidium are recognized. Type-I (with jugal processes) and Type-II (without jugal processes), both having normal primary lamellae, could give rise to each other by losing/re-evolving the jugal processes. Type-III, without jugal processes, originated from Type-II through evolution of the modified lateral-convex primary lamellae, and it subsequently gave rise to Type-IV by evolving the modified medial-convex primary lamellae. The evolution of brachidia within individual evolutionary lineages must be clarified because two or more types can be present within a single family. Type-III and Type-IV are closely associated with the prolongation of the crura, representing innovative modifications of the feeding apparatus in response to possible shift in the position of the mouth towards the anterior, allowing for more efficient feeding on particles entering the mantle cavity from the anterior gape. Meanwhile, the modified primary lamellae adjusted/regulated the feeding currents. The absence of spires in some taxa with Type-IV brachidium might suggest that they developed a similar lophophore to that in some extant brachiopods, which can extend out of the shell.

Two new variants of the Rhodococcus equi virulence plasmid, 90 kb type III and type IV, recovered from a foal in Japan

2001 ◽  
Vol 82 (4) ◽  
pp. 373-381 ◽  
Author(s):  
Shinji Takai ◽  
Norihisa Murata ◽  
Ryudai Kudo ◽  
Nobuhiro Narematsu ◽  
Tsutomu Kakuda ◽  
...  
Keyword(s):  
Rhodococcus Equi ◽  
Virulence Plasmid ◽  
Type Iii ◽  
Type Iv

scholarly journals Serum Levels of Laminin, Type IV Collagen and Type III Procollagen Peptide as Markers for Detection of Metastasis

1994 ◽  
Vol 85 (12) ◽  
pp. 1263-1269 ◽  
Author(s):  
Kazuo Yudoh ◽  
Hisao Matsui ◽  
Masahiko Kanamori ◽  
Kazuo Ohmori ◽  
Haruo Tsuji ◽  
...  
Keyword(s):  
Type Iv Collagen ◽  
Serum Levels ◽  
Type Iii ◽  
Type Iv ◽  
Type Iii Procollagen ◽  
Type Iii Procollagen Peptide
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