Experimental Study on the Impact of Slope and Silt-laden inflow Conditions on Vegetation Sediment Trapping Process

2020 ◽  
Author(s):  
Mingjie Luo ◽  
Chengzhong Pan ◽  
Chunlei Liu
Keyword(s):  
Flow Rate ◽  
Influencing Factor ◽  
Stable State ◽  
Sediment Concentration ◽  
Trapping Efficiency ◽  
Sediment Trapping ◽  
Sediment Delivery ◽  
Trapping Effect ◽  
The Impact ◽  
Trapping Process

<p>Vegetation-restored hillslope surfaces not only reduce erosion but they also remove sediment from upslope silt-laden inflow. To investigate the sediment trapping effect of grassland, this study conducted a series of crossed sediment trapping experiments that examined various factors, such as slope (5°–20°), sediment concentration (40–160 g L<sup>−1</sup>), and unit flow rate (7.5–45.0 L min<sup>−1</sup> m<sup>−1</sup>). The duration of each experiment was longer than required to reach the stable state of sediment trapping, so we measured and verified the individual sediment trapping capacity (R<sub>m</sub>) by experiments. The results showed that gentler slopes generated higher instantaneous sediment trapping efficiency (ISTE) and greater R<sub>m</sub>. As the sediment concentration of the silt-laden inflow increased, the impact of slope on R<sub>m</sub> increased. Higher sediment concentration led to lower ISTE but greater R<sub>m</sub>. Similar to the effect of sediment concentration, a larger unit flow rate led to lower ISTE and greater R<sub>m</sub>. Thus, it is evident that interaction among these factors affects sediment trapping process. The experiments revealed the greatest sediment trapping effect of grass strips was concentrated mainly in the first 2-m width, and that 90% of sediment deposition occurred within half the time needed to reach the stable state. Slope and flow rate were found to have an effect on sediment trapping in each section of grass strips, whereas the effect of sediment concentration was concentrated primarily in the first 5-m width. Standard regression coefficients of a comprehensive regression analysis showed that the intensities of the influencing factors on R<sub>m</sub> were as follows: slope (0.736) > grassland width (0.498) > unit flow rate (0.398) > sediment concentration (0.240). It was established that slope is the strongest influencing factor, and that sediment concentration and unit flow rate mainly affect R<sub>m</sub> by changing the rate of sediment delivery. These results will help expand the theoretical basis regarding the effects of vegetation restoration on watersheds in soil erosion research.</p>

Uncovering the impact of delay phenomenon on random walks in a family of weighted m-triangulation networks

2021 ◽  
pp. 2150234
Author(s):  
Junhao Guo ◽  
Zikai wu
Keyword(s):  
Random Walk ◽  
Random Walks ◽  
Analytical Solutions ◽  
Network Models ◽  
Trapping Efficiency ◽  
Trapping Time ◽  
Delay Phenomenon ◽  
The Impact ◽  
Insight Into ◽  
Trapping Process

Uncovering the impact of special phenomena on dynamical processes in more distinct weighted network models is still needed. In this paper, we investigate the impact of delay phenomenon on random walk by introducing delayed random walk into a family of weighted m-triangulation networks. Specifically, we introduce delayed random walk into the networks. Then one and three traps are deployed, respectively, on the networks in two rounds of investigation. In both rounds of investigation, average trapping time (ATT) is applied to measure trapping efficiency and derived analytically by harnessing iteration rule of the networks. The analytical solutions of ATT obtained in both investigations show that ATT increases sub-linearity with the size of the network no matter what value the parameter [Formula: see text] manipulating delayed random walk takes. But [Formula: see text] can quantitatively change both its leading scaling and prefactor. So, introduction of delay phenomenon can control trapping efficiency quantitatively. Besides, parameters [Formula: see text] and [Formula: see text] governing networks’ evolution quantitatively impact both the prefactor and leading scaling of ATT simultaneously. In summary, this work may provide incremental insight into understanding the impact of observed phenomena on special trapping process and general random walks in complex systems.

scholarly journals Effects of Different Aboveground Structural Parts of Grass Strips on the Sediment-Trapping Process

2021 ◽  
Vol 13 (14) ◽  
pp. 7591
Author(s):  
Mingjie Luo ◽  
Chengzhong Pan ◽  
Yongsheng Cui ◽  
Yahui Guo ◽  
Yun Wu
Keyword(s):  
Overland Flow ◽  
Sediment Concentration ◽  
Sediment Deposition ◽  
Sediment Trapping ◽  
Flow Process ◽  
Initial Stage ◽  
Structural Parts ◽  
And Control ◽  
Total Sediment ◽  
Trapping Process

Grass strips can decrease erosion, trap sediment in silt-laden water flowing downhill, and control nonpoint source pollution. Determining the effects of different parts of grass strips on silt-laden overland flow will improve our understanding of sediment trapping by grass strips with different structures. Sediment trapping by grass strips was studied using a 5° slope, 30 L min−1 m−1 flow rate, 120 g L−1 sediment concentration, and different aboveground components of grass strips (complete grass, removed green grass, and removed green and withered grass). The whole overland flow process was monitored. Meanwhile, the runoff sediment samples at the outlet were collected and measured. Sediment trapping by aboveground grass parts was quantified at different stages. Of the soil bed surface, green grass, and withered grass, the soil bed surface dominated sediment trapping in the initial stage of the sediment-trapping process, contributing about 90% of total sediment deposition in the first 5 min. As the sediment-trapping process continued, the effect of the soil bed surface weakened, and the green grass played a major role at the later stage of sediment trapping. The ratio of the soil bed surface, green grass, and withered grass contributions to total sediment deposition at the stable stage of the experiments was approximately 3:5:2. The results will help assess the effects of vegetation restoration on sediment transport in entire watersheds.

scholarly journals Estimating the Sediment Flux and Budget for a Data Limited Rift Valley Lake in Ethiopia

Hydrology ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 1 ◽  
Author(s):  
Alemu Aga ◽  
Assefa Melesse ◽  
Bayou Chane
Keyword(s):  
Rift Valley ◽  
Sediment Concentration ◽  
Management Program ◽  
Sediment Flux ◽  
Trapping Efficiency ◽  
Lake Basin ◽  
Watershed Model ◽  
Sediment Trapping ◽  
Regression Methods ◽  
Lake Outlet

Information on sediment concentration in rivers is important for the design and management of reservoirs. In this paper, river sediment flux and siltation rate of a rift valley lake basin (Lake Ziway, Ethiopia) was modeled using suspended sediment concentration (SSC) samples from four rivers and lake outlet stations. Both linear and non-linear least squares log–log regression methods were used to develop the model. The best-fit model was tested and evaluated qualitatively by time-series plots, quantitatively by using watershed model evaluation statistics, and validated by calculating the prediction error. Sediment yield (SY) of ungauged rivers were assessed by developing and using a model that includes catchment area, slope, and rainfall, whereas bedload was estimated. As a result, the gross annual SY transported into the lake was 2.081 Mton/year. Annually, 0.178 Mton/year of sediment is deposited in floodplains with a sediment trapping rate of 20.6%, and 41,340 ton/year of sediment leaves the lake through the Bulbula River. The annual sediment deposition in the lake is 2.039 Mton/year with a mean sediment trapping efficiency of 98%. Based on the established sediment budget with average rainfall, the lake will lose its volume by 0.106% annually and the lifetime of Lake Ziway will be 947 years. The results show that the approach used can be replicated at other similar ungauged watersheds. As one of the most important sources of water for irrigation in the country, the results can be used for planning and implementing a lake basin management program targeting upstream soil erosion control.

Impact Of Transurethral Resection Of Prostate On International Prostate Symptom Score And Peak Urinary Flow Rate

2020 ◽  
Vol 16 (1) ◽  
pp. 11-15
Author(s):  
Md Waliul Islam ◽  
Md Abul Hossain ◽  
Md Nurul Hooda ◽  
Kazi Rafiqul Abedin ◽  
Husne Ara
Keyword(s):  
Flow Rate ◽  
Transurethral Resection ◽  
Urine Volume ◽  
T Test ◽  
Urinary Symptoms ◽  
Urinary Flow Rate ◽  
Transurethral Resection Of Prostate ◽  
Urinary Flow ◽  
Paired Student ◽  
The Impact

Objectives: To evaluate urinary symptoms and quality of life in patient with BPH before and after TURP. To determine the impact of TURP on the urinary symptoms (IPSS) and peak urinary flow rate. Methods: This study is prospective study carried out between 2010 and 2011 in the department of Urology, National Institute of Kidney Diseases & Urology. Total 102 cases were selected purposively according to selection criteria. Each patient was observed and followed up at 8 weeks (1st visit), 16 weeks (2nd visit) 24 weeks (3rd visit) after transurethral resection of prostate (TURP). IPSS score, QOL score also recorded and uroflowmetry was done to see the peak urinary flow rate (Qmax) of urine and voiding time. USG was done to see post voidal residual urine volume and DRE also done in selected cases. Data was complied and statistical analysis were done using computer based software, Statistical Package for Social Science (SPSS), using paired ‘t’ test. A P value <0.05 was taken as significance. Results: Before TURP, IPSS range 17-25 and mean 21.61+2.43, after TURP, range 0-7 and mean 4.27+1.71). Hence a significant improvement of IPSS was found from 2 months to 6 months follow up after TURP. The change was tested using “paired student ‘t’ test”. Before TURP Qmax range 7-12.2 and mean was 9.96+1.69, which became range 18-25 and mean was 22.61+2.28 after TURP and therefore change of mean Qmax was 12.64+2.69. The change was tested using “paired student ‘t’ test”. The change was found significant (P<0.001). Conclusion: Transurethral resection of prostate resolves obstructive symptoms, rapid improvement of urinary flow rate Bangladesh Journal of Urology, Vol. 16, No. 1, Jan 2013 p.11-15

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Research on the impact of ship traffic flow on the restricted channel segment of the middle Yangtze River based on traffic wave theory

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Ting Liu ◽  
Gabriel Lodewijks
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Flow Simulation ◽  
Wave Theory ◽  
Flow Density ◽  
List Type ◽  
Ship Traffic ◽  
Traffic Wave ◽  
The Impact ◽  
Channel Segment

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

scholarly journals Evaluation of the impact of viscosity, injection volume, and injection flow rate on subcutaneous injection tolerance

2015 ◽  
pp. 473 ◽  
Author(s):  
Florence Schwarzenbach ◽  
Cecile Berteau ◽  
Orchidee Filipe-Santos ◽  
Tao Wang ◽  
Humberto Rojas ◽  
...  
Keyword(s):  
Flow Rate ◽  
Subcutaneous Injection ◽  
Injection Volume ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
The Impact

scholarly journals A Mathematical Model for Swallowing of Concentrated Fluids in Oesophagus

2011 ◽  
Vol 8 (3-4) ◽  
pp. 309-321 ◽  
Author(s):  
S. K. Pandey ◽  
Dharmendra Tripathi
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Plug Flow ◽  
Flow Region ◽  
Mechanical Efficiency ◽  
Casson Fluid ◽  
Local Pressure ◽  
Integral Number ◽  
Tomato Puree ◽  
The Impact

This model investigates particularly the impact of an integral and a non-integral number of waves on the swallowing of food stuff such as jelly, tomato puree, soup, concentrated fruits juices and honey transported peristaltically through the oesophagus. The fluid is considered as a Casson fluid. Emphasis is on the study of the dependence of local pressure distribution on space and time. Mechanical efficiency, reflux limit and trapping are also discussed. The effect of Casson fluid vis-à-vis Newtonian fluid is investigated analytically and numerically too. The result is physically interpreted as that the oesophagus makes more efforts to swallow fluids with higher concentration. It is observed that the pressure is uniformly distributed when an integral number of waves is there in the oesophagus; but it is non-uniform when a non-integral number of waves is present therein. It is further observed that as the plug flow region widens, the pressure difference increases, which indicates that the averaged flow rate will reduce for a Casson fluid. It is also concluded that Casson fluids are more prone to reflux.

Cultural influence on brand loyalty of rural consumers in the Indian context

2017 ◽  
Vol 11 (1) ◽  
pp. 60-72 ◽  
Author(s):  
Rashmi Ranjan Parida ◽  
Sangeeta Sahney
Keyword(s):  
Brand Loyalty ◽  
Influencing Factor ◽  
Cultural Factors ◽  
Business Organizations ◽  
Market Strategy ◽  
Content Type ◽  
Four Dimensions ◽  
Rural Market ◽  
Rural Consumers ◽  
The Impact

Purpose The purpose of the study is to develop a scale to identify and measure cultural factors and brand loyalty among rural consumers. The study also seeks to analyze the impact of identified cultural factors on the overall brand loyalty of rural consumers. Design/methodology/approach A questionnaire was developed to measure cultural factors and brand loyalty of rural consumers. Exploratory factor analysis was carried out to identify cultural factors, and a regression analysis was carried out to study the impact of the identified factors on brand loyalty. Findings Four dimensions of culture were identified from the study, i.e. virtuousness, religion, sociability and ethnocentrism. The analysis reveals that virtuousness is the most influencing factor on brand loyalty of rural consumers, followed by sociability and religion. Ethnocentrism was found to have insignificant influence on brand loyalty. Research limitations/implications The Indian rural market is a market of opportunity and unlimited business potential. An understanding of the cultural factors of rural markets and their influence on brand loyalty would help marketers and business organizations build an appropriate market strategy to explore benefits. Originality/value The paper attempts to explore the influence of certain cultural factors on the brand loyalty of Indian rural consumers, which has not been researched extensively. This provides a good insight for all marketers who want to succeed in this market.

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