main channel
Recently Published Documents


TOTAL DOCUMENTS

584
(FIVE YEARS 187)

H-INDEX

33
(FIVE YEARS 4)

2022 ◽  
Author(s):  
Bandita Naik ◽  
Vijay Kaushik ◽  
Munendra Kumar

Abstract The computation of the boundary shear stress distribution in an open channel flow is required for a variety of applications, including the flow resistance relationship and the construction of stable channels. The river breaches the main channel and spills across the floodplain during overbank flow conditions on both sides. Due to the momentum shift between the primary channel and adjacent floodplains, the flow structure in such compound channels becomes complicated. This has a profound impact on the shear stress distribution in the floodplain and main channel subsections. In addition, agriculture and development activities have occurred in floodplain parts of a river system. As a consequence, the geometry of the floodplain changes over the length of the flow, resulting in a converging compound channel. Traditional formulas, which rely heavily on empirical approaches, are ineffective in predicting shear force distribution with high precision. As a result, innovative and precise approaches are still in great demand. The boundary shear force carried by floodplains is estimated by gene expression programming (GEP) in this paper. In terms of non-dimensional geometric and flow variables, a novel equation is constructed to forecast boundary shear force distribution. The proposed GEP-based method is found to be best when compared to conventional methods. The findings indicate that the predicted percentage shear force carried by floodplains determined using GEP is in good agreement with the experimental data compared to the conventional formulas (R2 = 0.96 and RMSE = 3.395 for the training data and R2 = 0.95 and RMSE = 4.022 for the testing data).


Data ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Margaret Kalacska ◽  
J. Pablo Arroyo-Mora ◽  
Oliver T. Coomes ◽  
Yoshito Takasaki ◽  
Christian Abizaid

We describe a new minimum extent, persistent surface water classification for reaches of four major rivers in the Peruvian Amazon (i.e., Amazon, Napo, Pastaza, Ucayali). These data were generated by the Peruvian Amazon Rural Livelihoods and Poverty (PARLAP) Project which aims to better understand the nexus between livelihoods (e.g., fishing, agriculture, forest use, trade), poverty, and conservation in the Peruvian Amazon over a 35,000 km river network. Previous surface water datasets do not adequately capture the temporal changes in the course of the rivers, nor discriminate between primary main channel and non-main channel (e.g., oxbow lakes) water. We generated the surface water classifications in Google Earth Engine from Landsat TM 5, 7 ETM+, and 8 OLI satellite imagery for time periods from circa 1989, 2000, and 2015 using a hierarchical logical binary classification predominantly based on a modified Normalized Difference Water Index (mNDWI) and shortwave infrared surface reflectance. We included surface reflectance in the blue band and brightness temperature to minimize misclassification. High accuracies were achieved for all time periods (>90%).


2022 ◽  
Vol 2022 (1) ◽  
pp. 013403
Author(s):  
Liping Lian ◽  
Xu Mai ◽  
Weiguo Song ◽  
Jun Zhang ◽  
Kwok Kit Richard Yuen ◽  
...  

Abstract Merging pedestrian flow can be observed often at public intersections and locations where two or more channels merge. Because of restrictions on the flow, pedestrian congestion, or even crowd disasters (e.g. Hajj crush 2015) happen easily at these junctions. However, studies on merging behaviors in large crowds remain rare. This paper investigates the merging characteristics of the pedestrian flow with controlled experiments under laboratory conditions. The formation of lanes is observed, and the lane separation width can vary for different density levels. Shannon entropy is used to analyze the utilization of the passage. The space usage in the merging area is most efficient when the width of the two branches is half that of the main corridor. Furthermore, the branch and main channel can mutually bottleneck each other in the large crowds and the flowrates for the upstream, downstream and branches are investigated. This study uses spatiotemporal diagrams to explore the clogging propagation of the merging flow as well as the relationship of the velocity and position. The results can be used as references for the design of public infrastructure and human safety management.


2022 ◽  
Vol 82 ◽  
Author(s):  
W. Khan ◽  
N. N. Nisa ◽  
S. Pervez ◽  
S. Ahmed ◽  
M. S. Ahmed ◽  
...  

Abstract The study reveals the prevalence of a potential rodent-borne zoonotic helminth species, Hymenolepis diminuta in commensal rodents caught from irrigated and rain-fed areas of Swat, Pakistan. Three hundred and fifty rodents (269 rats and 81 mice) trapped during vegetative, flowering/fruiting and mature/harvesting stages of crops were studied from 2011-2013. Hymenolepisdiminuta eggs were identified on the basis of their shape, size, colour and markings on the surface of the egg shell and three pairs of embryonic hook-lets. Overall prevalence of H. diminuta was 3.14% (n=11/350). The highest prevalence 3.49% (n=5/143) of H. diminuta was noted at harvesting stages of the crops whereas the lowest 2.59% (n=2/77) during vegetative stage. Infection was higher in males 3.25% (n=7/215) than females 2.96% (n=4/135). Adult rodents were highly infected while no sub-adult was found infected. Infection was higher in mice 3.70% (3/81) than rats 2.69% (8/269) while no significance (p=1.0000:0.1250 to 32.00 CI). Rats and mice appears to show the most suitable reservoirs by hosting H. diminuta a zoonotic helminth. The presence of these rodents in all possible habitats can act as a main channel of transferring parasites through various habitats and can pose a hazard to humans in the area.


2021 ◽  
Vol 6 (2) ◽  
pp. 20
Author(s):  
Liping Zhang ◽  
Pengwei Lv

Patriotic education in the new era needs to give full play to the role of the main channel of ideological and political courses, strengthen and improve the ideological and political work team, strengthen the construction of practical education base. At the same time, we will continue to explore new channels for educating people, and will fully integrate patriotic education with cultural and moral education. Students need to strengthen their ideals and beliefs, cultivate their patriotism, and turn their patriotism into a trip to serve the country.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mingrui Song ◽  
Yijun Zhao ◽  
Xianguo Li ◽  
Lu Meng

With the development of Internet e-commerce channels, online shopping platforms have become the main channel for consumers to buy nearly expired food. Date labels, as one of the main external clues, play a decisive role in nearly expired food purchasing. Therefore, based on attention-related theory, this study attempts to explore the influence exerted by different time frames on consumers’ willingness to buy and its mechanism. The results show that compared with the date, consumers have a higher willingness to buy nearly expired food when the expiration time is framed by delay. More specifically, compared to the date, the delay causes the individual to have a longer time perception, thus more preference for nearly expired food. Meanwhile, the mediating effect of time perception is moderated by food type. The conclusion of this research is helpful to expand the theoretical framework of time frames and related fields on nearly expired food, as well as provide practical guidance for marketers to effectively promote nearly expired food.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Haiying Yang

The thinking course is an innovative move to implement the fundamental task of moral education and realize the whole process of education and all-round education in universities. The Apriori-TIDS algorithm proposed in this paper adopts the TID list of transaction identifiers to calculate the support count and generate the frequent item set of the Hou option set, and the whole frequency set generation process only needs to scan the transaction database once, which greatly improves the operation efficiency of the mining algorithm. The course is based on the three focus points of ideological and political education, such as “matters, times, and situations”, to explore the elements of ideological and political education hidden in the course, and to give the principles and criteria for evaluating the effectiveness of ideological and political teaching in the course, in order to make the professional degree course become the main channel to lead the ideological and political education of postgraduate courses and improve the effectiveness of the course in educating people.


Check List ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. 1681-1714
Author(s):  
Melanie L. J. Stiassny ◽  
S. Elizabeth Alter ◽  
Tobit L. D. Liyandja ◽  
Myriam Y. Modimo ◽  
Raoul J. C. Monsembula Iyaba

Despite the cultural and economic importance of fisheries to communities in the region, the Mfimi is one of the least well-documented river systems in the central Congo basin. Here we present a preliminary listing of species collected during two surveys sampling 35 sites along the main channel, in major tributaries, and in some marginal habitats. A total of 2195 specimens representing 141 species were collected and archived at the American Museum of Natural History, New York, and in the teaching collections of the University of Kinshasa. Five species are considered as potentially new to science, and range extensions of numerous species into the Mfimi are recorded. Based on the data presented we conclude that the fish communities in the Mfimi share affinities with those of the Cuvette Centrale to the north, rather than the Kasai basin with which the river is currently connected via an inflow at the Kwa-Kasai junction.


Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3451
Author(s):  
Weicheng Lo ◽  
Chih-Tsung Huang ◽  
Meng-Hsuan Wu ◽  
Dong-Jiing Doong ◽  
Leng-Hsuan Tseng ◽  
...  

In recent years, climate change has been widely discussed around the world. The Intergovernmental Panel on Climate Change (IPCC) published the Sixth Assessment Report (AR6) in 2021, which stated that with the intensification of global warming, heavy rainfalls are becoming more severe and frequent. Economic development in recent years has also caused the proportion of impervious areas in urban regions to increase with the advancement of urbanization. When the two aforementioned factors are coupled together, the result is faster surface runoff speeds and reduced infiltration rates, which in turn result in worse flooding. Thus, water disaster mitigation is becoming a topic of great importance to developed and developing countries. This study examined five Nature-based Solutions (NbS) cases (A, B C, D, E) for the Nangang river in Taiwan. Case A is to design levees with a 100-year return period flood design standard. Under steady flow conditions, floods can be smoothly discharged downstream without any significant inundation in most situations. Case B and C used gabions with a 10-year return period flood design standard and discontinuous levees with a 25-year return period flood design standard, respectively. Though neither case is as effective in flood mitigation, both cases B and C can still reduce inundation from the flooding disaster relatively well. Case D is to dredge local areas of the main channel, but the steady flow simulation showed little flood mitigation effect. Case E is the implementation of “Room for the River”, and employs main channel dredging and floodplain land grading to increase flood conveyance capacity. Case E provides good flood mitigation.


2021 ◽  
Vol 3 (4) ◽  
pp. 471-486
Author(s):  
Abhijit Banerjee ◽  
Esther Duflo ◽  
Garima Sharma

This paper studies the long-run effects of a “ big-push” program providing a large asset transfer to the poorest Indian households. In a randomized controlled trial that follows these households over ten years, we find positive effects on consumption (0.6 SD), food security (0.1 SD), income (0.3 SD), and health (0.2 SD). These effects grow for the first seven years following the transfer and persist until year ten. One main channel for persistence is that treated households take better advantage of opportunities to diversify into more lucrative wage employment, especially through migration. (JEL I32, I38, J22, J31, O12, O18)


Sign in / Sign up

Export Citation Format

Share Document