Oxygen Transfer through Air Entrainment in Riparian Riffles: A Case Study of Seomjin River, Korea

2015 ◽  
Vol 74 (3) ◽  
Author(s):  
Jin-Hong Kim
Keyword(s):  
Oxygen Transfer ◽  
Particle Diameter ◽  
Air Entrainment ◽  
Field Investigation ◽  
Average Value ◽  
River Bed ◽  
Trailing Edges ◽  
Upstream Part ◽  
Seomjin River

Field investigation on the oxygen transfer through the air entrainment, the riffle geometries, and the relationships between the efficiency of the oxygen transfer and the hydraulic parameters in the riparian riffles were performed. Investigation of the air entrainment and measurements of the oxygen transfer in the riffles were conducted. Types of bed height in the riffles were upward convex. Slopes of the water surface and the river bed were steeper at the downstream rather than at the upstream part. Air entrainment occurred more frequently in the edged gravels rather than in the round and edgeless gravels, and it was formed mainly from behind the trailing edges of the gravels. Oxygen transfer was found to be proportional to the flow velocity, the flow discharge, and the Froude number, but not closely related to the particle diameter. Average value of oxygen transfer in the riffles of the study area was about 0.085, which shows good habitat condition for the aquatic creatures. 

scholarly journals Deep Learning Based Instance Segmentation of Titanium Dioxide Particles in the Form of Agglomerates in Scanning Electron Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 968
Author(s):  
Paul Monchot ◽  
Loïc Coquelin ◽  
Khaled Guerroudj ◽  
Nicolas Feltin ◽  
Alexandra Delvallée ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Titanium Dioxide ◽  
Learning Community ◽  
Spherical Particles ◽  
Average Value ◽  
Size Characterization ◽  
Scanning Electron

The size characterization of particles present in the form of agglomerates in images measured by scanning electron microscopy (SEM) requires a powerful image segmentation tool in order to properly define the boundaries of each particle. In this work, we propose to use an algorithm from the deep statistical learning community, the Mask-RCNN, coupled with transfer learning to overcome the problem of generalization of the commonly used image processing methods such as watershed or active contour. Indeed, the adjustment of the parameters of these algorithms is almost systematically necessary and slows down the automation of the processing chain. The Mask-RCNN is adapted here to the case study and we present results obtained on titanium dioxide samples (non-spherical particles) with a level of performance evaluated by different metrics such as the DICE coefficient, which reaches an average value of 0.95 on the test images.

scholarly journals How effective is river restoration in re-establishing groundwater–surface water interactions? – A case study

2015 ◽  
Vol 19 (6) ◽  
pp. 2663-2672 ◽  
Author(s):  
A.-M. Kurth ◽  
C. Weber ◽  
M. Schirmer
Keyword(s):  
Surface Water ◽  
River Restoration ◽  
Morphological Changes ◽  
Cost Effective ◽  
Urban Stream ◽  
Distributed Temperature Sensing ◽  
River Bed ◽  
Before And After ◽  
Restoration Measures

Abstract. In this study, we investigated whether river restoration was successful in re-establishing groundwater–surface water interactions in a degraded urban stream. Restoration measures included morphological changes to the river bed, such as the installation of gravel islands and spur dykes, as well as the planting of site-specific riparian vegetation. Standard distributed temperature sensing (DTS) and novel active and passive DTS approaches were employed to study groundwater–surface water interactions in two reference streams and an experimental reach of an urban stream before and after its restoration. Radon-222 analyses were utilized to validate the losing stream conditions of the urban stream in the experimental reach. Our results indicated that river restoration at the study site was indeed successful in increasing groundwater–surface water interactions. Increased surface water downwelling occurred locally at the tip of a gravel island created during river restoration. Hence, the installation of in-stream structures increased the vertical connectivity and thus groundwater–surface water interactions. With the methods presented in this publication, it would be possible to routinely investigate the success of river restorations in re-establishing vertical connectivity, thereby gaining insight into the effectiveness of specific restoration measures. This, in turn, would enable the optimization of future river restoration projects, rendering them more cost-effective and successful.

scholarly journals Scaling for lobe and cleft patterns in particle-laden gravity currents

2013 ◽  
Vol 20 (1) ◽  
pp. 121-130 ◽  
Author(s):  
A. Jackson ◽  
B. Turnbull ◽  
R. Munro
Keyword(s):  
Granular Material ◽  
Froude Number ◽  
Particle Diameter ◽  
Granular Flows ◽  
Leading Edge ◽  
Air Entrainment ◽  
Gravity Currents ◽  
Laboratory Scale ◽  
Scale Model ◽  
Snow Avalanches

Abstract. Lobe and cleft patterns are frequently observed at the leading edge of gravity currents, including non-Boussinesq particle-laden currents such as powder snow avalanches. Despite the importance of the instability in driving air entrainment, little is known about its origin or the mechanisms behind its development. In this paper we seek to gain a better understanding of these mechanisms from a laboratory scale model of powder snow avalanches using lightweight granular material. The instability mechanisms in these flows appear to be a combination of those found in both homogeneous Boussinesq gravity currents and unsuspended granular flows, with the size of the granular particles playing a central role in determining the wavelength of the lobe and cleft pattern. When scaled by particle diameter a relationship between the Froude number and the wavelength of the lobe and cleft pattern is found, where the wavelength increases monotonically with the Froude number.

scholarly journals PENERAPAN PBL MELALUI PEMBUATAN TAMAN RUMPUT PADA MATERI LINGKARAN DI KELAS VIII

2019 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Dian Septa Novari ◽  
Indah Widyaningrum ◽  
Widiawati W.
Keyword(s):  
Student Learning ◽  
Learning Outcomes ◽  
Experimental Research ◽  
Student Learning Outcomes ◽  
Average Value ◽  
Class Viii ◽  
The Creation ◽  
Pbl Model

This study aims to determine 1) the student's activity during the implementation of PBL models and 2) student learning outcomes after the implementation of PBL models through the creation of grass park on the material circle in class VIII SMP Negeri 1 Pagaralam. This research is an experimental research category one shot case study involving 32 students of class VIII SMP Negeri 1 Pagaralam. The results showed that the activity of students during the loading applied to the model PBL through grass park is categorized as very active seen from the activity of visual, verbal, listening, metrics, and writing. While student learning outcomes after the implementation of the PBL model through the creation of grass park are categorized very well as indicated by the average value of students. Thus, the PBL model is very suitable for use in mathematics, especially in the area of a circle of matter.

scholarly journals The economics the correlation issues in EU-28

2016 ◽  
Vol 5 (1-2) ◽  
pp. 77-82
Author(s):  
Yaser Mueeth A. Alkahtani ◽  
Zoltán László Szabó ◽  
Gan Quan
Keyword(s):  
Social Protection ◽  
Purchase Power Parity ◽  
Strong Correlations ◽  
Power Parity ◽  
Member States ◽  
Average Value ◽  
Bartlett’S Test ◽  
Statistical Program ◽  
The Eu

In this case study the analyses focus on the some correlation compares among EU-28 member states. Also the analyses focus on the wide side overview for the EU-28 member states using eight variances of three principal components for EU-28. The economic growing rate of EU-28 member states concerning some economic issues as GDP growing rate, employment, unemployment accompanying with social protection and government debt, price fluctuating, purchase power parity of consumers and also probably lifelong learning. The eight numbers according to each variance give the average value of KMO, which shows in the first line of T able T. KMO and Bartlett's Test, namely 0.628. In this case all of other variances expect RisPov2014 have strong correlations with themselves. The LLeam2014 has the strongest correlations by value of 0.767 (76%), also the GovDebt2014 has strong one, by 0.744 (74%), HICPan2014 has 0.731 (73%), the GDPcap2014 has value of 0.706 (70.6%). This SPSS statistical program can help to make clear overview for the correlations and differences among EU-28 member states from different issues and approaches, as variances. Also it is important, when the researchers choose these variances; they should know that the correlations among variances based on the principle components. These last one can select variances into different components, which mostly can explain the role and importance of each variance.

scholarly journals Investment Of Fixed Equipment Assets On Improving Profitability (case study cv.Parahyangan Express BranchKarawang)

2020 ◽  
Vol 17 (1) ◽  
pp. 30-42
Author(s):  
Sri Suartini ◽  
Dian Hakip Nurdiansyah ◽  
Sheli Rosdayanti
Keyword(s):  
Primary Data ◽  
Test Results ◽  
Fixed Asset ◽  
Financial Report ◽  
Verification Method ◽  
Average Value ◽  
Fixed Assets ◽  
Data Source ◽  
Fixed Asset Investment

The purpose of this study to determine how much influence of fixed asset investment vehicles against profitability CV. Parahyangan Express Karawang Branch. This research uses a descriptive verification method with a primary data source that is a financial report CV. Parahyangan Express Karawang Branch period 2007 to 2016. The result of this research is r average investment value CV. Parahyangan Express in the period 2007 until 2016 tends to decrease, the average value of profitability CV. Parahyang n Express in the period 2007 to 2016 tends to decline. Based on test results t comparison t arithmetic with t table showing 2.840> 2.093 t count more than t table. vehicle fixed asset investment has a significant effect on profitability in a CV. Parahyangan Express. The percentage of influence of fixed asset investment of 30% means 30 % development of profitability CV. Parahyangan Express is influenced by in-kind fixed assets while 70 % is influenced by other factors not examined in this study.

scholarly journals Productive Protection of Intangible Cultural Heritage Based on the Theory of Involvement: A Case Study on the Farmers’ Paintings of XinJi County, Hebei Province, China

2020 ◽  
Vol 86 ◽  
pp. 01031
Author(s):  
Kong Xuhong ◽  
Hong Jingjing
Keyword(s):  
Cultural Heritage ◽  
Field Investigation ◽  
Hebei Province ◽  
Intangible Cultural Heritage ◽  
Cultural Connotation ◽  
Involvement Theory ◽  
Present Context ◽  
History Of ◽  
The Times

The productive protection of intangible cultural heritages, always in the form of tourism development under the present context, is put forward by Chinese scholars, which are beneficial to both the protection of the heritage and the economy development of the locals. While not all intangible cultural heritages can be understood and accepted by tourists due to the reasons that the living circumstances and contexts of these heritages are changing and disappearing that it’s hard for tourists to understand, neither do they desire to pay for it. Therefore, how to make tourists even including some craftsmen understand and accept the heritage means a lot to the protection and inheritance of these heritages. The paper argues that the Involvement Theory can be referred to analyze settle the problems. A case study of the farmers’ painting in Xinji County, Hebei Province was carried out as the example, which is one of the most representative intangible cultural heritage of folk art in Hebei Province, China, with a long history of development, rich cultural connotation and high artistic value. A field investigation and deep-interview was carried out to gather the information of its status quo, problems of its inheriting and developing were analyzed, the paper found that with the development of the times and society, farmers’ painting is losing its survival environment, the income of farmers’ painting is not proportional to their putting-in and cost, the value of farmers painting can not be reflected, and the productive protection is seriously hindered. Therefore, based on the perspective of involvement theory, this study analyzed the bottleneck of productive protection of Xinji Farmers’ Painting, suggested how to stimulate the involvement of tourists into the understanding and producing and creation of the paintings in order to promote the inheritance of the heritage.

scholarly journals Evaluation of the Influence Caused by Tunnel Construction on Groundwater Environment: A Case Study of Tongluoshan Tunnel, China

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Jian Liu ◽  
Dan Liu ◽  
Kai Song
Keyword(s):  
Indicator System ◽  
Field Investigation ◽  
Assessment Method ◽  
Tunnel Construction ◽  
Moderate Degree ◽  
Tunnel Excavation ◽  
Construction Period ◽  
Environmental Investigation ◽  
Groundwater Environment

Problems related to water inflow during tunnel construction are challenging to designers, workers, and management departments, as they can threaten tunneling project from safety, time, and economic aspects. Identifying the impacts on groundwater environment resulting from tunnel drainage and making a correct assessment before tunnel construction is essential to better understand troubles that would be encountered during tunnel excavation and helpful to adopt appropriate countermeasures to minimize the influences. This study presents an indicator system and quantifies each indicator of Tongluoshan tunnel, which is located in southwest China with a length of 5.2 km and mainly passes through carbonate rocks and sandstones, based on field investigation and related technological reports. Then, an evaluation is made using fuzzy comprehensive assessment method, with a result showing that it had influenced the local groundwater environment at a moderate degree. Information fed back from environmental investigation and hydrologic monitoring carried out during the main construction period proves the evaluation, as the flow of some springs and streams located beside the tunnel route was found experiencing an apparent decline.

The Effect of Nozzle Type on Air Entrainment by Plunging Water Jets

2002 ◽  
Vol 37 (3) ◽  
pp. 599-612 ◽  
Author(s):  
Tamer Bagatur ◽  
Ahmet Baylar ◽  
Nusret Sekerdag
Keyword(s):  
Penetration Depth ◽  
Oxygen Transfer ◽  
Free Water ◽  
Air Entrainment ◽  
Water Jet ◽  
Transfer Efficiency ◽  
Entrainment Rate ◽  
Water Jets ◽  
Air Entrainment Rate ◽  
Oxygen Transfer Efficiency

Abstract In this study, for the plunging water jet aeration system using various inclined nozzle types, bubble penetration depth, air entrainment rate, water jet expansion, effect of water jet circumference at impact point, oxygen transfer coefficient and oxygen transfer efficiency which changed depending on the water jet velocity, were researched in an air-water system. Numerous studies were conducted with circular nozzles. The present study describes new experiments performed with different nozzle types. Three types of nozzles were examined, i.e., those with circular, ellipse and rectangle duct with rounded ends. Experimental results showed that water jets produced with ellipse and rectangle duct with rounded ends nozzles have very different flow characteristics, entrainment patterns on free water jet surface, and submerged water jet region within the receiving tank. Higher air entrainment rate and oxygen transfer efficiency was observed in the rectangle duct with rounded ends nozzle due to water jet expansion. Bubble penetration depth, however, is lower for the rectangle duct with rounded ends nozzle than for the other nozzles. The ellipse nozzle provided the highest bubble penetration depth. These results showed that it is appropriate to use ellipse nozzle in aeration of deep pool and rectangle duct with rounded ends nozzle in the applications where high bubble concentration is desirable.

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