scholarly journals Numerical Investigation of the Combined Slot Effect on the Erosion Pattern Around a Combination of Spur Dikes in Series

2021 ◽  
Author(s):  
Khosrow Hosseini ◽  
Shahab Nayyer ◽  
Mehran Kheirkhahan ◽  
Sayed-Farhad Mousavi
Keyword(s):  
Flood Control ◽  
Effective Area ◽  
The Body ◽  
Scour Depth ◽  
Spur Dike ◽  
Bed Erosion ◽  
Geometrical Shapes ◽  
In Series ◽  
Spur Dikes ◽  
The Web

Abstract Modifying the river course for flood control, prevention of bed erosion, bank protection, and the regulation of river width are among the goals of spur dikes incorporation. The common spur dikes have simple (I), L and T geometrical shapes. The present research has been conducted to reduce the scour depth in front of the spurs dikes and improve the sedimentation conditions for the LTT combination of spur dikes in series by investigating different combinations of slots in the body of the spur dike; using numerical methods. The slot dimension was taken equal to 10% of the effective area of the spur dike body. Finally, the (LS-W-Wi, TS-W, TS-W-Wi) combination contained the slots in the web and wing of the first and third spur dike also the slot at the web of the middle spur dike was found as the best combination of slots. This combination conducted to reduce the scour depth about 6.8% and increase the deposition about 52% comparing by the spurs dikes without slots. Reducing the scour depth and increasing the sedimentation rate of materials between the spurs dikes. Also, the maximum scour depth decreases up to 20%. The results revealed that the presence of slots in spur dike structures and their different positions have complicated and considerable influences on the form and morphology of the erodible bed which could be the topic for further researches.

scholarly journals Estimation of maximum scour depth near a spur dike

2016 ◽  
Vol 43 (3) ◽  
pp. 270-278 ◽  
Author(s):  
Manish Pandey ◽  
Z. Ahmad ◽  
P.K. Sharma
Keyword(s):  
Natural Phenomenon ◽  
Scour Depth ◽  
Flowing Water ◽  
Performance Indices ◽  
Spur Dike ◽  
Bed Erosion ◽  
River Bed ◽  
Spur Dikes ◽  
Dike Failure ◽  
Better Than

Scour is a natural phenomenon in rivers caused by the erosive action of the flowing water on the bed and banks. Spur dikes are constructed across the flow to protect the bank from erosion by shifting of the river away from the bank. The spur dike undermines due to river-bed erosion and scouring, which is generally recognized as the main cause of spur dike failure. In this study, accuracy of existing equations for the computation of maximum scour depth has been checked with available data in the literature and data collected in the present study using graphical and statistical performance indices. Three new relationships are also proposed to estimate the maximum scour depth and maximum scour length upstream and downstream of spur dike. This new relationship for maximum scour depth is shown to perform better than other existing equations.

scholarly journals Numerical Simulation of the Influence of Spur Dikes Spacing on Local Scour and Flow

2019 ◽  
Vol 9 (11) ◽  
pp. 2306
Author(s):  
Jian Ning ◽  
Guodong Li ◽  
Shanshan Li
Keyword(s):  
Shear Stress ◽  
Pearson Correlation ◽  
Fixed Bed ◽  
Maximum Velocity ◽  
Turbulent Energy ◽  
Local Scour ◽  
Shielding Effect ◽  
Scour Depth ◽  
Spur Dike ◽  
Spur Dikes

The spacing of spur dikes is an important consideration for the layout of spur dike channels. This study focuses on the local scour morphology and flow field characteristics of spur dikes with different spacings. The results show that the maximum scour depth is generally found in the vicinity of the first spur dike head. With the increase of the spacing of spur dikes, the shielding effect of the first spur dike is weakened. The maximum velocity in the main flow zone is twice that of the approach flow velocity in the fixed bed. But it is approximately the same as the incoming velocity in equilibrium scouring. The maximum turbulent energy appears to be mainly located in the backflow area of the fourth spur dike in the fixed bed, while the maximum value appears at the second spur dike head in the movable bed. Further, the shear stress decreases as scouring develops. Pearson correlation analysis was carried out between scour depth and shear stress. The analysis results are significantly correlated, indicating that the bed shear stress plays a prominent role in the scouring process. These discoveries can serve as a guide to determine the most reasonable spacing of spur dikes.

scholarly journals Prediction of time variation of scour depth around spur dikes using neural networks

2011 ◽  
Vol 14 (1) ◽  
pp. 180-191 ◽  
Author(s):  
Hojat Karami ◽  
Abdollah Ardeshir ◽  
Mojtaba Saneie ◽  
S. Amin Salamatian
Keyword(s):  
Neural Networks ◽  
Regression Model ◽  
Time Variation ◽  
Back Propagation ◽  
Maximum Depth ◽  
Scour Depth ◽  
Effective Parameters ◽  
Spur Dike ◽  
Feed Forward Back Propagation ◽  
Spur Dikes

The maximum depth of scouring around spur dikes plays an important role in the hydraulic design process. There have been many studies on the maximum depth of scouring, but there is little information available on the time variation of scour depth. In this paper, the time variation of scouring around the first spur dike in a series was investigated experimentally. Experiments were carried out in four different bed materials under different flow intensities (U/Ucr). To achieve a time development of scouring around the first spur dike, more than 750 sets of experimental data were collected. The results showed that 70–90% of the equilibrium scour depths were occurring during the initial 20% of the overall time of scouring. Based on the data analysis, a regression model and artificial neural networks (ANNs) were developed. The models were compared with other empirical equations in the literature. However, the results showed that the developed regression model is quite accurate and more practical, but the ANN models by feed forward back propagation and radial basis function provide a better prediction of observation. Finally, by sensitivity analysis, the most and the least effective parameters, which affected time variation of scouring, were determined.

scholarly journals Numerical scour modeling around parallel spur dikes in FLOW-3D

2017 ◽  
Author(s):  
Hanif Pourshahbaz ◽  
Saeed Abbasi ◽  
poorya taghvaei
Keyword(s):  
Numerical Model ◽  
3D Model ◽  
Flow Characteristics ◽  
3D Models ◽  
Scour Depth ◽  
Spur Dike ◽  
Accuracy Level ◽  
Bank Protection ◽  
Numerical Research ◽  
Spur Dikes

Abstract. Spur dikes are some structures which are built in the flow path with the aim of changing flow characteristics in order to bed and bank protection in rivers. These sudden changes in properties caused by the existence of spur dikes, produces erosion and sedimentation around them. In this paper, effects of series of parallel spur dikes have been investigated numerically. For this purpose, by using experimental and numerical research results from technical literatures, the numerical model conducted in FLOW-3D commercial software and the data were compared with experimental and SSIIM results. The results showed that Froude number and the ratio of U/Ucr affect the accuracy of the models. As a result, by discharge increasing, FLOW-3D models need to be calibrated again. Also, by using a calibrated FLOW-3D model, calculation accuracy of the scour depth at the bottom of the spur dikes becomes better and the accuracy level in the modeling of the surface morphology improves 7 percent more than SSIIM software in the bottom of the first spur dike, more than 80 percent at the bottom of the second spur dike and approximately 40 percent at the bottom of the last spur dike.

ANALYSIS OF THE CREW PART OF THE LOCOMOTIVE TEM23 AND PROPOSALS FOR ELIMINATION OF DISADVANTAGES

2020 ◽  
Author(s):  
Dmitriy Antipin ◽  
Vladimir Vorobev ◽  
Denis Bondarenko ◽  
Gennadiy Petrov
Keyword(s):  
Vertical Plane ◽  
The Body ◽  
Diesel Locomotive ◽  
Design Features ◽  
Bogie Frame ◽  
Spring Suspension ◽  
In Series

The analysis of the design features of the bogie of the TEM23 shunting diesel locomotive is carried out. In the process of analysis, the directions of its improvement are determined. It is proposed to rotate the bogie frame in the vertical plane by reducing the body supports to two and using a pivot with low lowering, equip the bogies with pneumatic spring suspension in the form of two corrugations installed in series with shortened suspension springs. The proposed options for improving the undercarriage of a diesel locomotive will increase the competitiveness of products and reduce costs

Understanding Semantic Web: a conceptual model

2015 ◽  
Vol 64 (1/2) ◽  
pp. 82-100 ◽  
Author(s):  
Michael Calaresu ◽  
Ali Shiri
Keyword(s):  
Semantic Web ◽  
Conceptual Model ◽  
The Body ◽  
Three Dimensional Model ◽  
Conceptual Approach ◽  
Web Based ◽  
Content Type ◽  
Software Applications ◽  
Web Architecture ◽  
The Web

Purpose – The purpose of this article is to explore and conceptualize the Semantic Web as a term that has been widely mentioned in the literature of library and information science. More specifically, its aim is to shed light on the evolution of the Web and to highlight a previously proposed means of attempting to improve automated manipulation of Web-based data in the context of a rapidly expanding base of both users and digital content. Design/methodology/approach – The conceptual analysis presented in this paper adopts a three-dimensional model for the discussion of Semantic Web. The first dimension focuses on Semantic Web’s basic nature, purpose and history, as well as the current state and limitations of modern search systems and related software agents. The second dimension focuses on critical knowledge structures such as taxonomies, thesauri and ontologies which are understood as fundamental elements in the creation of a Semantic Web architecture. In the third dimension, an alternative conceptual model is proposed, one, which unlike more commonly prevalent Semantic Web models, offers a greater emphasis on describing the proposed structure from an interpretive viewpoint, rather than a technical one. This paper adopts an interpretive, historical and conceptual approach to the notion of the Semantic Web by reviewing the literature and by analyzing the developments associated with the Web over the past three decades. It proposes a simplified conceptual model for easy understanding. Findings – The paper provides a conceptual model of the Semantic Web that encompasses four key strata, namely, the body of human users, the body of software applications facilitating creation and consumption of documents, the body of documents themselves and a proposed layer that would improve automated manipulation of Web-based data by the software applications. Research limitations/implications – This paper will facilitate a better conceptual understanding of the Semantic Web, and thereby contribute, in a small way, to the larger body of discourse surrounding it. The conceptual model will provide a reference point for education and research purposes. Originality/value – This paper provides an original analysis of both conceptual and technical aspects of Semantic Web. The proposed conceptual model provides a new perspective on this subject.

scholarly journals CHANGES IN FINE STRUCTURE DURING SILK PROTEIN PRODUCTION IN THE AMPULLATE GLAND OF THE SPIDER ARANEUS SERICATUS

1969 ◽  
Vol 42 (1) ◽  
pp. 284-295 ◽  
Author(s):  
Allen L. Bell ◽  
David B. Peakall
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Protein Production ◽  
Distal Portion ◽  
Silk Gland ◽  
The Body ◽  
Single Type ◽  
Secretory Cells ◽  
The Web ◽  
Tunica Intima

The ampullate silk gland of the spider, Araneus sericatus, produces the silk fiber for the scaffolding of the web. The fine structure of the various parts of the gland is described. The distal portion of the duct consist of a tube of epithelial cells which appear to secrete a substance which forms the tunica intima of the duct wall. At the proximal end of the duct there is a region of secretory cells. The epithelium of the sac portion contains five morphologically distinct types of granules. The bulk of the synthesis of silk occurs in the tail of the gland, and in this region only a single type of secretory droplet is seen in the epithelium. Protein synthesis can be stimulated by the injection of 1 mg/kg acetylcholine into the body fluids. 10 min after injection, much of the protein stored in the cytoplasm of the epithelial cells has been secreted into the lumen. 20 min after stimulation, the ergastoplasmic sacs form large whorls in the cytoplasm. Protein, similar in electron-opacity to protein found in the lumen, begins to form in that portion of the cytoplasm which is enclosed by the whorls. The limiting membrane of these droplets is formed by ergastoplasmic membranes which lose their ribosomes. No Golgi material has been found in these cells. Protein appears to be manufactured in the cytoplasm of the tail cells in a form which is ready for secretion.

Estimation of maximum local scour depth around submerged spur-dike

2016 ◽  
pp. 193-199
Author(s):  
S.Y. Hao ◽  
Y.F. Xia ◽  
H. Xu
Keyword(s):  
Local Scour ◽  
Scour Depth ◽  
Spur Dike

Human pose estimation based on parallel atrous convolution and body structure constraints

2021 ◽  
pp. 1-11
Author(s):  
Min Zhang ◽  
Haijie Yang ◽  
Pengfei Li ◽  
Ming Jiang
Keyword(s):  
Pose Estimation ◽  
The Body ◽  
Human Pose Estimation ◽  
Spatial Relationships ◽  
Body Structure ◽  
Convolutional Network ◽  
In Series ◽  
Human Pose ◽  
Ablation Study ◽  
View Transformation

Human pose estimation is still a challenging task in computer vision, especially in the case of camera view transformation, joints occlusions and overlapping, the task will be of ever-increasing difficulty to achieve success. Most existing methods pass the input through a network, which typically consists of high-to-low resolution sub-networks that are connected in series. Still, during the up-sampling process, the spatial relationships and details might be lost. This paper designs a parallel atrous convolutional network with body structure constraints (PAC-BCNet) to address the problem. Among the mentioned techniques, the parallel atrous convolution (PAC) is constructed to deal with scale changes by connecting multiple different atrous convolution sub-networks in parallel. And it is used to extract features from different scales without reducing the resolution. Besides, the body structure constraints (BC), which enhance the correlation between each keypoint, are constructed to obtain better spatial relationships of the body by designing keypoints constraints sets and improving the loss function. In this work, a comparative experiment of the serial atrous convolution, the parallel atrous convolution, the ablation study with and without body structure constraints are conducted, which reasonably proves the effectiveness of the approach. The model is evaluated on two widely used human pose estimation benchmarks (MPII and LSP). The method achieves better performance on both datasets.

scholarly journals Scour around Spur Dike in Sand–Gravel Mixture Bed

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1417 ◽  
Author(s):  
Manish Pandey ◽  
Wei Haur Lam ◽  
Yonggang Cui ◽  
Mohammad Amir Khan ◽  
Umesh Kumar Singh ◽  
...  
Keyword(s):  
Water Depth ◽  
Velocity Ratio ◽  
Maximum Error ◽  
Length Ratio ◽  
Scour Depth ◽  
Spur Dike ◽  
Particle Ratio ◽  
Cause Of Failure ◽  
Equilibrium Scour Depth ◽  
Sediment Mixture

Scour is the main cause of failure for spur dike. The accurate prediction of scour around spur dike is essential to design a spur dike. The present study focuses on the maximum scour depth in equilibrium condition and parameters, which influence it in a sand–gravel mixture bed. Outcomes of the present experimental study showed that the non-dimensional maximum equilibrium scour depth increases with critical velocity ratio (U/Uca), water depth-armour particle ratio (h/da), Froude number for sediment mixture (Frsm), water depth-spur dike length ratio (h/l), and decreases with increase in armour particle-spur dike length ratio (da/l). The maximum scour depth is proportional to dimensionless parameters of U/Uca, h/da, Frsm, h/l, but the scour depth is inverse proportional to da/l. Scour around spur dike in a sand–gravel mixture is mainly influenced by the property of the sediment mixture. The scour increases with decrease in non-uniformity of the sediment mixture. A non-linear empirical equation is proposed to estimate the maximum scour depth at an upstream nose of rectangular spur dike with a maximum error of 15%. The sensitivity analysis indicates that the maximum non-dimensional equilibrium scour depth depends on Frsm, followed by the secondary sensible parameters da/l, h/l, and h/da.

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