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The quadrotor suspended payload systems have difficulties to achieve precise positioning of the quadrotor UAV and suppression of the load swing angle at the same time because of their characteristics, such as underactuated, strongly coupling, nonlinear and so on. An enhanced coupling anti-swing controller is proposed to solve these problems. With analysis on the relationship between the displacement of quadrotor UAV and the payload swing angle, the three-dimensional dynamic variable rope length model of a quadrotor UAV based on Euler–Lagrange equation is built. An anti-swing method based on energy coupling is designed for this system to realize positioning and eliminate the problem of residual load swing. A new auxiliary signal function is constructed to enhance the coupling relationship between UAV position and load position. The control strategy of three-dimensional quadrotor UAV is designed based on the signal function by the Lyapunov stability theory. The stability of this system is proved by the Lyapunov method and the Barbalat's Lemma. With the experiment, the proposed method is compared with different control methods, the results show that the proposed method can realize the accurate positioning of the quadrotor UAV more quickly and restrain the load swing more effectively. It has strong robustness and stability after the system is added to the disturbance. [ABSTRACT FROM AUTHOR]

National Capital Integrated Coastal Development (NCICD) aims to protect Jakarta from flooding. This project includes a coastal reservoir (CR) development plan at the Cisadane Estuary, Tangerang Regency, Indonesia. CR planning must consider the sedimentation process. With numerical modelling of sediment transport, the sedimentation pattern of bed load and suspended load sediments will be known. This study used the MIKE21/3 Integrated Models software that is coupled with Flow Model (FM) and Mud Transport (MT) for one year (August 1, 2020 - July 31, 2021). The validation result of surface elevation shows that the modelling results are valid with NRMSD 93.35%. Based on the simulation results, suspended sediment concentration in the west monsoon is higher than in the east. The sediment concentration around the coastal reservoir at the bottom layer of the water is slightly higher than the surface layer. There is an increase in the maximum bed thickness of 1.2 m in the northeast corner of CR. There is a reduction in the bottom thickness of about 0.5 m on the west side of the CR embankment. The results of this study can be used to develop the most optimal CR design to minimise the environmental impacts. [ABSTRACT FROM AUTHOR]

Riverbeds often fine downstream, with a gravel‐bedded reach, a relatively abrupt gravel‐sand transition (GST), and a sand‐bedded reach. Underlying this behavior, bed grain size distributions are often bimodal, with a relative paucity (gap) around the range 1–5 mm. There is no general morphodynamic model capable of producing the grain size gap and gravel‐sand transition autogenically from a unimodal sediment supply. Here we use a one‐dimensional morphodynamic model including size‐specific bedload and suspended load transport, to show that bimodality readily evolves autogenically even under unimodal sediment feed. A GST forms when we include a floodplain width that abruptly increases at some point. Upstream of the transition, non‐gap gravel ceases to move and gap sediment is preferentially transported. At the transition, non‐gap sand rapidly deposits from suspension, enhancing gap sediment mobility and diluting its presence on the bed. Plain Language Summary: The bed surface layer of many rivers is a mixture of sand and gravel. This mixture is described by the probability distribution of grain sizes, and in particular by the median size. Consider the long profile of such a river. Surface median size commonly becomes finer downstream, but often changes abruptly from a value above 5 mm to a value below 1 mm over a short reach. The range 1–5 mm is termed "gap sediment." Here we explain how this abrupt change evolves, even when there is no deficit of gap sediment supplied to the reach, and even though particle abrasion is not included. The grain size distribution autogenically develops two peaks, one in the sand range and one in the gravel range above 5 mm. When abrupt floodplain widening is included, the gravel peak is stronger in the upper reach and the sand peak is stronger in the lower reach, leading to a relatively abrupt gravel‐sand transition. Gap sediment can be diluted both upstream and downstream by a combination of effects due to bedload and suspended load, so that it dominates nowhere in the grain size distribution. Key Points: Numerical simulations show that bed bimodality evolves autogenically, even with unimodal sediment feed and no abrasionAbrupt floodplain widening can lead to the formation of a distinct gravel‐sand transitionThe behavior can be explained by preferential mobility of 1–5 mm sediment over a sand bed combined with fallout of sand from suspension [ABSTRACT FROM AUTHOR]

Sedimentation in rivers is a major issue of environmental damage in the Kepulauan Bangka Belitung Province. In the last two decades, since tin mining was carried out by the community, massive sedimentation has occurred in the river. The purpose of the study is to investigate the characteristics of sediment materials and the effects of illegal tin mining on river sedimentation on Bangka Island. Sediment characteristics can be seen from the distribution of grain size and specific gravity of the bed sediment material and the concentration of suspended sediments seen from their position along the river. Sediment grain size is classified according to the American Geophysical Union. A total of 45 sediment samples spread across 12 rivers in the district capital area on Bangka Island were collected at the end of the rainy season in 2023, and 4 more samples were added in the dry season of 2023 in the Muntok River. The MPM formula was applied to estimate bedload transport and statistical methods were used to estimate suspended sediment rates. Additionally, the sedimentation rates are estimated based on dependable continuous flow with a probability exceeding 50% (Q50%). The study's findings indicate that Illegal tin mining in Bangka Island has a major impact on river sedimentation. The particle size distribution of bed material sediments does not align with what is typically found in nature, which often exhibits coarser particles upstream and finer downstream. Similarly, in areas downstream of tin mining operations, the concentration of suspended particles increases significantly, up to 12 times higher than natural conditions. [ABSTRACT FROM AUTHOR]

Sediment connectivity at the catchment scale includes the processes linking sediment sources, sinks and the river outlet. Soil erosion models usually estimate yields without considering riverine processes or human infrastructure that may affect sediment connectivity. Quantifying these processes at a large scale is a determinant of understanding sediment transfers from continental lands to marine ecosystems. This study tries to fill this gap by coupling the soil erosion model WaTEM/SEDEM (WS) with the riverine connectivity tool CASCADE to quantify sediment fluxes in the Rhône watershed. The coupling returned a good fit, with deviations of −51.7%. WS alone predicts the exported fluxes better with a deviation of −34.9%. Nevertheless, this paper shows the importance of considering connectivity and transport capacity to develop a more realistic representation of fine sediment dynamics at a large scale. However, connectivity tools depend on the quality of the models (soil erosion and hydrology) and the geomorphological data on which they depend, which is a limiting factor in large‐scale studies. [ABSTRACT FROM AUTHOR]

Introduction Rivers are always faced with erosion and sediment transport. Sediment transport in rivers is one of the most complex topics in river engineering and is always the focus of experts and water engineers. This phenomenon is one of the important hydrodynamic processes that affect many hydraulic systems and water facilities and is considered one of the basic problems in the exploiting surface water resources globally. Estimating the sediment load of rivers is one of the important and practical issues in the studies and design of water engineering projects, such as the design and development of irrigation and drainage networks, water extraction from rivers, etc. Sediment concentration can be calculated by direct or indirect methods, which are usually expensive and timeconsuming direct methods. Various factors affect this phenomenon, which makes their analysis difficult. Therefore, they cannot model the sedimentation phenomenon with acceptable accuracy. Hydraulic models cannot always be trusted due to the need for a lot of data, unavailability of the required data, and the inaccuracy of the data due to human error for simulating sediments. Nowadays, fuzzy and neural intelligent conductor systems, due to their ability to solve complex and nonlinear phenomena, have found many applications in various water engineering problems, including sedimentation. The purpose of this research is to evaluate and compare adaptive neural fuzzy models (ANFIS), support vector machine (SVM), gene expression programming (GEP), and group model of data handling (GMDH) in estimating the sediment load of Tirah River, Markazi Province. Materials and Methods In this research, first, the long-term daily statistics of temperature, rainfall, average flow rate, and sediment concentration of Hasan Abad hydrometric and sediment measuring station located on the main branch of the Tirah River were collected. Then, the data sufficiency test for analysis, checking the correlation between parameters of river discharge, precipitation, temperature with sediment discharge, and determining the long-term average of suspended sediment in the studied stations were performed. In the next step, a suitable combination of input variables was selected. The design of the input parameter pattern can be based on the relationship between flow and sediment flow parameters, rainfall, temperature, flow, and sediment flow. Of course, considering that the mentioned parameters have a historical course, therefore, the design of the input patterns of soft computing models should be done based on time delays (like what is discussed in the analysis and forecasting of time series). Determining the most appropriate time delay of the input parameters in the modeling of discharge, sediment, temperature, and rainfall, then the appropriate design of the structure of the used soft calculation models was done. In the next step, the estimation of sediment discharge using an SVM, GEP, and ANFIS group method of GMDH data control and comparison of three data mining methods, and also with the sediment rating curve and observational data. About 70 % of the research data was used as training and between 20 to 30 % for validation and testing. Results and Discussion Based on the statistical indicators of optimal model selection, the best performance of the SVR model has been obtained for model number one. In this model, the R² and RMSE obtained from the model are 0.96 and 0.0047, respectively. Besides, the R² and the RMSE error of the models in predicting suspended sediment values in the test stage are 0.95 and 0.014, respectively for the ANFIS model, and 0.50 and 4.97, respectively for the GEP model. The best performance of the ANFIS model has been obtained for model number one. In this model, the R2 and the RMSE obtained from the model are 0.95 and 0.014. The R² and RMSE of the models in predicting suspended sediment values in the test stage are 0.96, 0.0047 for the SVR model, and 0.50, 4.97 for the GEP model, respectively. The best performance of the GEP model has been obtained for pattern number nine. In this model, the R² and RMSE obtained from the model are 0.99 and 0.010, respectively. The R² and the RMSE of the models in predicting the amount of suspended sediment in the test stage are respectively equal to 0.70, 0.015 for the ANFIS model and 0.78, 0.0185 tons respectively for the SVR model. Conclusion It can be seen that the performance of the GEP model was better compared to other models. SVR and ANFIS models are ranked second and third. In the next step, the best-selected pattern of ANFIS, SVM, and GEP models was used as the input of the GMDH model. First, input pattern one, which was selected as the best pattern for ANFIS and SVM models, was introduced as the input of the GMDH model. In the training and test, the values of R² statistical indices are 0.94 and 0.99, respectively, the RMSE error value is 0.0079 and 0.0038, respectively, the MSE value is 0.000062 and 0.000015, respectively, and the MAPE values are respectively 0.007 and 0.003. In the next step, input pattern nine, which was selected as the best pattern for the GEP model, is introduced as GMDH input. In the training and test steps, the value of R² is equal to 0.95 and 0.98 respectively, the RMSE error value is equal to 0.0077 and 0.0045 respectively, and the MSE value is equal to 0.0006 and 0.00002 respectively, and MAPE value is equal to 363 and 502. The results showed the acceptable performance of the GMDH model [ABSTRACT FROM AUTHOR]

Sedimentation in rivers is a major issue of environmental damage in the Kepulauan Bangka Belitung Province. In the last two decades, since tin mining was carried out by the community, massive sedimentation has occurred in the river. The purpose of the study is to investigate the characteristics of sediment materials and the effects of illegal tin mining on river sedimentation on Bangka Island. Sediment characteristics can be seen from the distribution of grain size and specific gravity of the bed sediment material and the concentration of suspended sediments seen from their position along the river. Sediment grain size is classified according to the American Geophysical Union. A total of 45 sediment samples spread across 12 rivers in the district capital area on Bangka Island were collected at the end of the rainy season in 2023, and 4 more samples were added in the dry season of 2023 in the Muntok River. The MPM formula was applied to estimate bedload transport and statistical methods were used to estimate suspended sediment rates. Additionally, the sedimentation rates are estimated based on dependable continuous flow with a probability exceeding 50% (Q50%). The study’s findings indicate that Illegal tin mining in Bangka Island has a major impact on river sedimentation. The particle size distribution of bed material sediments does not align with what is typically found in nature, which often exhibits coarser particles upstream and finer downstream. Similarly, in areas downstream of tin mining operations, the concentration of suspended particles increases significantly, up to 12 times higher than natural conditions.

Abstract Riverbeds often fine downstream, with a gravel‐bedded reach, a relatively abrupt gravel‐sand transition (GST), and a sand‐bedded reach. Underlying this behavior, bed grain size distributions are often bimodal, with a relative paucity (gap) around the range 1–5 mm. There is no general morphodynamic model capable of producing the grain size gap and gravel‐sand transition autogenically from a unimodal sediment supply. Here we use a one‐dimensional morphodynamic model including size‐specific bedload and suspended load transport, to show that bimodality readily evolves autogenically even under unimodal sediment feed. A GST forms when we include a floodplain width that abruptly increases at some point. Upstream of the transition, non‐gap gravel ceases to move and gap sediment is preferentially transported. At the transition, non‐gap sand rapidly deposits from suspension, enhancing gap sediment mobility and diluting its presence on the bed.

Introduction Rivers are always faced with erosion and sediment transport. Sediment transport in rivers is one of the most complex topics in river engineering and is always the focus of experts and water engineers. This phenomenon is one of the important hydrodynamic processes that affect many hydraulic systems and water facilities and is considered one of the basic problems in the exploiting surface water resources globally. Estimating the sediment load of rivers is one of the important and practical issues in the studies and design of water engineering projects, such as the design and development of irrigation and drainage networks, water extraction from rivers, etc. Sediment concentration can be calculated by direct or indirect methods, which are usually expensive and time-consuming direct methods. Various factors affect this phenomenon, which makes their analysis difficult. Therefore, they cannot model the sedimentation phenomenon with acceptable accuracy. Hydraulic models cannot always be trusted due to the need for a lot of data, unavailability of the required data, and the inaccuracy of the data due to human error for simulating sediments. Nowadays, fuzzy and neural intelligent conductor systems, due to their ability to solve complex and nonlinear phenomena, have found many applications in various water engineering problems, including sedimentation. The purpose of this research is to evaluate and compare adaptive neural fuzzy models (ANFIS), support vector machine (SVM), gene expression programming (GEP), and group model of data handling (GMDH) in estimating the sediment load of Tirah River, Markazi Province. Materials and Methods In this research, first, the long-term daily statistics of temperature, rainfall, average flow rate, and sediment concentration of Hasan Abad hydrometric and sediment measuring station located on the main branch of the Tirah River were collected. Then, the data sufficiency test for analysis, checking the correlation between parameters of river discharge, precipitation, temperature with sediment discharge, and determining the long-term average of suspended sediment in the studied stations were performed. In the next step, a suitable combination of input variables was selected. The design of the input parameter pattern can be based on the relationship between flow and sediment flow parameters, rainfall, temperature, flow, and sediment flow. Of course, considering that the mentioned parameters have a historical course, therefore, the design of the input patterns of soft computing models should be done based on time delays (like what is discussed in the analysis and forecasting of time series). Determining the most appropriate time delay of the input parameters in the modeling of discharge, sediment, temperature, and rainfall, then the appropriate design of the structure of the used soft calculation models was done. In the next step, the estimation of sediment discharge using an SVM, GEP, and ANFIS group method of GMDH data control and comparison of three data mining methods, and also with the sediment rating curve and observational data. About 70 % of the research data was used as training and between 20 to 30 % for validation and testing. Results and Discussion Based on the statistical indicators of optimal model selection, the best performance of the SVR model has been obtained for model number one. In this model, the R2 and RMSE obtained from the model are 0.96 and 0.0047, respectively. Besides, the R2 and the RMSE error of the models in predicting suspended sediment values in the test stage are 0.95 and 0.014, respectively for the ANFIS model, and 0.50 and 4.97, respectively for the GEP model. The best performance of the ANFIS model has been obtained for model number one. In this model, the R2 and the RMSE obtained from the model are 0.95 and 0.014. The R2 and RMSE of the models in predicting suspended sediment values in the test stage are 0.96, 0.0047 for the SVR model, and 0.50, 4.97 for the GEP model, respectively. The best performance of the GEP model has been obtained for pattern number nine. In this model, the R2 and RMSE obtained from the model are 0.99 and 0.010, respectively. The R2 and the RMSE of the models in predicting the amount of suspended sediment in the test stage are respectively equal to 0.70, 0.015 for the ANFIS model and 0.78, 0.0185 tons respectively for the SVR model. Conclusion It can be seen that the performance of the GEP model was better compared to other models. SVR and ANFIS models are ranked second and third. In the next step, the best-selected pattern of ANFIS, SVM, and GEP models was used as the input of the GMDH model. First, input pattern one, which was selected as the best pattern for ANFIS and SVM models, was introduced as the input of the GMDH model. In the training and test, the values of R2 statistical indices are 0.94 and 0.99, respectively, the RMSE error value is 0.0079 and 0.0038, respectively, the MSE value is 0.000062 and 0.000015, respectively, and the MAPE values are respectively 0.007 and 0.003. In the next step, input pattern nine, which was selected as the best pattern for the GEP model, is introduced as GMDH input. In the training and test steps, the value of R2 is equal to 0.95 and 0.98 respectively, the RMSE error value is equal to 0.0077 and 0.0045 respectively, and the MSE value is equal to 0.0006 and 0.00002 respectively, and MAPE value is equal to 363 and 502. The results showed the acceptable performance of the GMDH model with the highest R2 equal to 0.99 and 0.98 and the lowest RMSE equal to 0.0038 and 0.0045, respectively.

Confluences act as crucial intersection in a fluvial system as they regulate the flow, sediment, and geomorphological stability. Two of the natural occurrences that have an effect on hydro-morphological processes that characterize the channel are sediment movement and stream discharge. However, assessments of suspended sediment distribution patterns across channel confluences and functions of tributaries on sediment transfer in downstream streams are still inadequately explored. To fulfil this, a year-long field investigation was conducted around river confluence at various time scales during the hydrological season. The bathymetry of the confluence was performed using digital echo-sounding equipment, electro-magnetic current meter, and differential global positioning equipment. This study uses in situ measurement and empirical techniques to quantify the spatiotemporal distribution of suspended sediment particles. Furthermore, Yang's formula was used to analyze the sediment concentration, and several statistical standards were employed to establish a differentiation between predicted and observed data. The results illustrated that a good agreement has been achieved among the calculated and measured statistics based on the correlation coefficient value. According to the findings, 8% fewer errors in the quantification of suspended sediment were induced in the tributary than in the main river because of the very low flow of the tributary. The present ramifications can help increase our database and understanding of the dynamics of major river confluences. HIGHLIGHTS A year-long field investigation was carried out to assess short-term suspended sediment rates and stream flow rates.; Statistical analysis was concluded between observed and predicted data.; The grain size of bed material varied significantly among individual channels in a variety of fluvial circumstances.; The tributary channel reflects the fluctuations along the longitudinal gradient of sediment rate.;

The phenomenon of sediment transport has always affected many river and civil structures. Not knowing the exact amount of sediment, causes much damage. Correct estimation of river sediment concentration is essential for planning and managing water resources projects and environmental issues. For this, you can use the artificial intelligence method, which has high flexibility. In this research, adaptive neuro-fuzzy models (ANFIS), gene expression programming (GEP), support vector regression (SVR), Group Method of Data Handling (GMDH), and the classical method of sediment rating curve (SRC) were used to model and prediction. For this purpose, the daily data of temperature, rainfall, sediment, and discharge of the Jalair station located in the Markazi province of Iran were used. The results obtained from these five methods were compared with each other and with the measured data. To evaluate the methods used, correlation coefficient, root mean square error, mean absolute error, and Taylor diagram were used. The results show the acceptable performance of data mining methods compared to the Sediment rating curve. Also, the model's superiority (GEP) was shown with the highest coefficient of determination R2 with a value of 0.98 and the lowest root mean square error RMSE in terms of tons per day with a value of 3721. The efficiency of the ANFIS and GMDH model with R2 values of 0.93, 0.98, and RMSE values of 16556, and 18638 was somewhat better than the SVR model with an R2 value of 0.90 and RMSE value of 35158. [ABSTRACT FROM AUTHOR]

There is abundant evidence from fluvial landforms and deposits that Mars had rivers that actively transported sediment and shaped its surface. Sediment transport equations are playing a key role in quantifying river processes from these observations, which continue to increase in quality and quantity. In this study, we review sediment transport equations developed on Earth and isolate the effect of gravity for the case of an alluvial channel. We compare 33 formulas used to calculate the sediment transport rate, under transport‐limited conditions, for grain sizes that range from silt to boulders and a lognormal sediment distribution. Results indicate that for a given discharge, channel morphology and grain size, the lower gravity on Mars compared to Earth results in: (a) larger grains mobilized on Mars and transported in suspension, and (b) larger suspended sediment transport rates on Mars and therefore larger total transport rates. Importantly, the effect of gravity is different for bed load and suspended load, with nonlinearity at the bed load‐suspended load transition zone. Therefore, typical total‐load transport relations that do not distinguish between bedload and suspended load are not appropriate for other planets as they simplify the effect of gravity. Gravity‐driven differences in fluvial sediment transport should produce differences in sediment sorting, morphology and stratigraphy between Earth and Mars. Additionally, our results show how Earth‐derived fluvial sediment transport theory can be applied beyond Mars to other planets and moons. Plain Language Summary: There is much evidence that Mars had rivers that actively transported sediment and shaped its surface. Preserved ancient landscapes altered by water provide valuable insights into past processes on the planet's surface and the presence of water. To better understand these landforms, we rely on knowledge gained from systems on Earth. However, is it fair to do so when the gravity on Mars is much lower? How does gravity affect sediment transport and the landforms created by water? In this study, we isolate the effect of gravity on sediment transport by water with an analytical river model. We used 32 sediment transport formulas to compare sediment transport rates on Earth and Mars for the same conditions except gravity. The results show that larger grains are picked up by the flow on Mars and the transport rate of sediment traveling in suspension is higher, and therefore total transport as well. Because grains transported near and on the bed are less affected than the grains in suspension, the effect of gravity varies with the way of transport and hence grain size. Therefore, gravity‐driven differences in sediment transport by water should produce differences in sediment sorting, morphology and stratigraphy between Earth and Mars. Key Points: Fluvial sediment transport rates are higher on Mars than on Earth for the same discharge and channel geometryGravity affects suspended sediment transport more than bed load transport and could hence lead to differences in morphology and stratigraphyTotal load sediment transport equations should be avoided on other planets and moons due to simplified attribution of gravity [ABSTRACT FROM AUTHOR]

The construction of new breakwaters in Anzali port has had a significant impact on the water body of the Anzali international lagoon. The Anzali wetland is under threat from sediment influx from mountainous regions, and the study used satellite image processing to demonstrate how the construction of new breakwaters impedes the natural transfer of sediment from the lagoon to the sea. The methodology employed a hybrid approach combining two methods: normal water index (MNDWI) and supervised classification (SVM) to detect sediment accumulation in the wetland water zone. Following the construction of new breakwaters in 2009, an island formed and expanded exponentially in parts of Sorkhankol Wildlife Sanctuary's water body. This phenomenon is attributed to decreased water flow caused by increased cross-section current and volume of water, creating a dam-like function against channel flow leading to the sea. Consequently, sediments and suspended loads settle in Sorkhankol's water zone, leading to an increase in island area from 0.39 hectares to over 26 hectares during the studied period. Result showed Kappa coefficients by SVM algorithm for years 2002, 2010, 2012 and 2017 which were found to be 0.76, 0.62, 0.71 and 0.86 respectively indicating that SVM outperforms MNDWI in effectively monitoring landform changes. [ABSTRACT FROM AUTHOR]

Small urban areas, due to their specificity (high anthroposphere, multiple forms of land use, variable drainage conditions), are often overlooked in studies on soil erosion and sediment transport that predominantly focus on a large scale. The sediment yield from such small urban areas may greatly vary depending, for example, on the state of the land development. Therefore, its proper estimation is crucial for water resources management, improving urban runoff quality or designing and maintaining local retention ponds. In this study, two different approaches were applied to estimate sediment yield from a small urban catchment of Służew Creek, located in Warsaw, Poland. While the first was based on direct hydrological measurements and field samples, the second (indirect) used various empirical formulas to predict bed load transport (local formula of Skibiński) in the stream channel and the suspended sediment delivery from the catchment (USLE equation, Build‐up/Wash‐off model). The sediment load established according to the direct approach equals 714 Mg/year, of which 83 Mg/year results from the bed load transport and 631 Mg/year comes from the suspended sediment transport. The total sediment load calculated according to the indirect approach equals 579 Mg/year. The relative difference in loads calculated with these two methods is about 20%. This paper combines various established methods into a novel composite analysis of sediment yield. The methodology presented in this study may support the estimation of sediment load in small urban catchments with a heterogenous land use structure. Hence, it may support urban planning and water resources management in such small catchments. [ABSTRACT FROM AUTHOR]

Introduction Wind Erosion is the natural process of transportation and deposition of soil by wind. It is a common phenomenon occurred mostly in dry, sandy soils or anywhere the soil is loose, dry, and finely granulated. Heavy metals are found in the environment and soils may become contaminated by accumulation of heavy metals through emissions from the rapidly expanding industrial areas, mine tailings, disposal of high metal wastes, leaded gasoline and paints, land application of fertilizers, animal manures, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, spillage of petrochemicals, and atmospheric deposition. Soils are the major sink for heavy metals released into the environment by the aforementioned anthropogenic activities and their total concentration in soils persists for a long time after their introduction. The heavy metal contamination of soil and its potential risks to humans and the ecosystem is a significant concern. Windy deposition, which is the process of heavy metals being transported by erosive winds and deposited onto soil, is one of the sources of heavy metal contamination. Due to the geographical situation and climatic conditions such as arid soil, erosive winds are blown in periods of year in Tabas. Since wind are erosion is severe in this area, huge amounts of wind deposition accompanied with erosive winds entered into this town. Heavy metals through the windy deposition are suspended, translated and finally deposited in residential regions, which can create some problems for human health. Therefore, the knowledge of wind erosion and the human risk of these deposits is essential. The aim of this research was to determine the rate of wind erosion and the concentration of some heavy metals in these deposits. Materials and Methods For this purpose, the rate of suspended load was measured monthly from February 2021 to January 2022. Based on previous information from the erosive winds and storms, suspended depositions were gathered in some directions (north, northwest, northeast, west and southwest) of the Tabas entrance. In addition, the suspended load in the city center of Tabas was also measured. The cumulative load of suspended depositions was measured monthly and the concentration of some heavy metals such as manganese (Mn), iron (Fe), cupper (Cu), and zinc (Zn) were measured in these suspended particles. Soil digestion was made by Aqua regia (nitric acid and chloridric acid; ratio of 3:1), and after then atomic absorption was used to measure the total concentration of above heavy metals. Results and Discussion The results indicate that Tabas experiences significant wind deposition of suspended loads, with the highest rates entering from the northeast direction and the lowest rates from the southwest direction. This pattern aligns with the wind rose of Tabas, which illustrates the prevailing wind directions in the region. Additionally, substantial suspended loads are observed in the northwest and north directions. The variations in suspended load discharge reveal that the maximum discharge occurs in the city center of Tabas during the months of June and July 2021. This corresponds to the arid climate conditions of these months, where plant growth is limited, soil cohesion is low, and loose soil particles on the surface are susceptible to wind forces. As a result, these loose particles are easily detached by the wind, contributing to the high levels of suspended load. Regarding the spatial variation of heavy metals in suspended particles, the cumulative concentrations of Mn, Fe, Cu, and Zn are found to be higher in the west, northwest, north, and west directions, respectively. This suggests that these heavy metals are transported and deposited in specific areas within Tabas due to the prevailing wind patterns. In terms of temporal variation, the highest concentrations of Mn and Fe in suspended particles are observed in April 2021, predominantly in the northeast and west directions, respectively. On the other hand, the highest concentrations of Cu and Zn are found in May 2021, with the southwest and northeast directions being the primary deposition areas for each metal, respectively. These findings highlight the spatial and temporal dynamics of suspended load and heavy metal deposition in Tabas, emphasizing the influence of wind patterns and climatic conditions on these processes. Understanding these variations is crucial for assessing the potential risks associated with heavy metal contamination and implementing appropriate mitigation measures in the region. Conclusion The results of this research showed that most contents of the suspended load are entered from the northeast direction into Tabas. In addition, the spatial variation of heavy metals indicated that the concentrations of studied heavy metals (Mn, Fe, Cu, and Zn) in suspended particles, especially in the western, northwestern, and northern in spring, are very high and they can cause carcinogenic effects on human life. Therefore, the management practices should be mostly made in these directions to control or reduce soil erosion and reduce its damage effects.

As an extended application of unmanned aerial vehicle (UAV), the system of a quadrotor with suspended load has a good development prospect because of its flexible performance and stable structure. However, the suppressive swing of the load and the consequently swaying of the UAV may cause crashes during the flight transportation. In order to solve the above problems, this paper introduces a rope with elasticity and damping of the transportation system of quadrotor with suspended load, which reduces the swing of the load by increasing the dissipativity of the system, and establishes the dynamic model of the proposed system. Then a new adaptive controller with unknown mass parameter is designed based on energy analysis method. The stability of the closed-loop system is proved by Lyapunov method and LaSalle's invariance principle. Numerical simulation results show that the proposed adaptive controller can eliminate the effects of the uncertain mass, and the proposed system can reach the specified position rapidly and the swing of the load can converge quickly under the action of the controller, which avoids flight accidents. [ABSTRACT FROM AUTHOR]

Sediment transport load monitoring is important in civil and environmental engineering fields. Monitoring the total load is difficult, especially because of the cost of the bed load transport measurement. This study proposes estimation models for the suspended‐to‐total load fraction using dimensionless hydro‐morphological variables. Two prominent variable combinations were identified using the recursive feature elimination for support vector regression (SVR): (a) width‐to‐depth ratio, dimensionless particle size, flow Reynolds number, densimetric Froude number, and falling particle Reynolds number, and (b) flow Reynolds number, Froude number, and densimetric Froude number. The explicit relations between the suspended‐to‐total load fraction and the two combinations were revealed by two modern symbolic regression methods: multi‐gene genetic programming and Operon. The five‐variable SVR model showed the best performance. Clustering analyses using a self‐organizing map and Gaussian mixture model, respectively, identified the underlying relationships between dimensionless variables. Subsequently, the one‐at‐a‐time sensitivity of the input variables of the empirical models was investigated. The suspended‐to‐total load fraction is positively related to the flow Reynolds number and is inversely related to the densimetric Froude number. The models developed in this study are practical and easy to implement in other suspended sediment monitoring methods because they only require basic measurable hydro‐morphological variables, such as velocity, depth, width, and median bed material size. Key Points: Empirical models were developed to estimate the ratio of suspended sediment load to total load using three different machine‐learning modelsSensitivity and clustering analyses elucidate relations among physical variablesFlow Reynolds and densimetric Froude numbers are the two dominant parameters in the proposed empirical models [ABSTRACT FROM AUTHOR]

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The present paper studies the two-dimensional unsteady suspended sediment transport problem through an open channel turbulent flow that carries large amounts of sediments. Presence of large amounts of sediments causes separate, distinct horizontal layers that result to differences in density, which is called density stratification. Also, due to interactions with neighboring particles, a particle settles at a reduced speed relative to that of a single particle in clear fluid, which is called hindered settling. The model includes both of these effects and the governing equation, which is a nonlinear partial differential equation (PDE), has been solved by the finite difference (FD) method. The model has been validated with existing models under certain specific conditions. It is found that stratification causes a decrement in sediment concentration values and the effect becomes prominent as time increases until it reaches a stable value. A reverse result is obtained for the case of hindered settling and both the effects are visible mainly in the main suspension region. Finally, the model has been validated with a few existing models together with some experimental data at steady-state and far-field conditions. [ABSTRACT FROM AUTHOR]

This note proposes a new formula for predicting the self-cleansing velocity of suspended particles in sewer pipes. Dimensional analysis is carried out to develop a new equation based on sediment and hydraulic characteristics. Model performance is tested using experimental data collected at laboratory scale and benchmarking data from the literature. The accuracy of the developed formula is evaluated with the Coefficient of Determination (R2), the Mean Absolute Percentage Error (MAPE) and the Root Mean Squared Error (RMSE). Results demonstrate that the proposed equation is able to predict the particle Froude number and hence the self-cleansing velocity for a wide range of variations of sediment concentration, particle diameter, and hydraulic characteristics. [ABSTRACT FROM AUTHOR]

Quadrotors have been utilized in a variety of applications where the payload needs to be transferred from one location to another, such as in mine detection, load delivery through hazardous environments, or locations that are inaccessible to ground vehicles. In these applications, the payload will be suspended underneath the vehicle and is subjected to large oscillations due to external disturbances or the acceleration of the vehicle itself. In this article, the most recent advancements in controlling the quadrotors vehicles with suspended loads are presented including control algorithms and techniques to implement these controllers. These techniques include the hardware and sensors besides the testing techniques for the developed control algorithms.

A theoretical model is presented here for the transient grain-size distribution of non-uniform sediments in suspension over erodible sediment beds based on the advection–diffusion equation in a turbulent open channel flow. The effect of particle–particle interaction near the channel bed is included in the reference level computation. In addition, pick-up probability, non-ceasing probability and incipient probability of sediment particles are incorporated in the calculation of reference concentration. Non-uniform sediments settle at a different velocity compared to uniform sediment and the difference in settling velocity in suspension influences their concentration in suspension. The present model accounts for the influence of non-uniform sediment on settling velocity through hindered and hiding effects. The governing equations in the proposed model are solved using OpenFOAM, an open source finite-volume method (FVM)-based framework. When settling velocity is calculated from uniform and non-uniform sediment expressions, the concentration difference is notable, especially in medium-size particles. In some particular heights, grain-size distributions have been analyzed over time for different sediment beds. Observations indicate that, as time passes, the stronger peak of the bimodal grain-size distribution in suspension weakens, while the weaker peak strengthens, until the distribution achieves a steady state at a specific height. In addition, grain-size distributions at various vertical heights over a long period of time have also been studied. It is found that the grain-size distribution becomes more skewed at the finer end with increasing vertical height. In the absence of unsteady transport data, the simulated numerical results were compared with existing steady transport data for non-uniform particle size over a suitably high time. After a considerable amount of time, the model attains a steady state and the numerical results under steady-state conditions depict good correspondence with the experimental data. In contrast to the majority of previous works, the present model can predict the transient grain-size distribution and reveal several latent phenomena of particle–particle and particle–turbulence interaction in the presence of suspended sediment particles of various sizes. [ABSTRACT FROM AUTHOR]

Introduction Wind Erosion is the natural process of transportation and deposition of soil by wind. It is a common phenomenon occurred mostly in dry, sandy soils or anywhere the soil is loose, dry, and finely granulated. Heavy metals are found in the environment and soils may become contaminated by accumulation of heavy metals through emissions from the rapidly expanding industrial areas, mine tailings, disposal of high metal wastes, leaded gasoline and paints, land application of fertilizers, animal manures, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, spillage of petrochemicals, and atmospheric deposition. Soils are the major sink for heavy metals released into the environment by the aforementioned anthropogenic activities and their total concentration in soils persists for a long time after their introduction. The heavy metal contamination of soil and its potential risks to humans and the ecosystem is a significant concern. Windy deposition, which is the process of heavy metals being transported by erosive winds and deposited onto soil, is one of the sources of heavy metal contamination. Due to the geographical situation and climatic conditions such as arid soil, erosive winds are blown in periods of year in Tabas. Since wind are erosion is severe in this area, huge amounts of wind deposition accompanied with erosive winds entered into this town. Heavy metals through the windy deposition are suspended, translated and finally deposited in residential regions, which can create some problems for human health. Therefore, the knowledge of wind erosion and the human risk of these deposits is essential. The aim of this research was to determine the rate of wind erosion and the concentration of some heavy metals in these deposits. Materials and Methods For this purpose, the rate of suspended load was measured monthly from February 2021 to January 2022. Based on previous information from the erosive winds and storms, suspended depositions were gathered in some directions (north, northwest, northeast, west and southwest) of the Tabas entrance. In addition, the suspended load in the city center of Tabas was also measured. The cumulative load of suspended depositions was measured monthly and the concentration of some heavy metals such as manganese (Mn), iron (Fe), cupper (Cu), and zinc (Zn) were measured in these suspended particles. Soil digestion was made by Aqua regia (nitric acid and chloridric acid; ratio of 3:1), and after then atomic absorption was used to measure the total concentration of above heavy metals. Results and Discussion The results indicate that Tabas experiences significant wind deposition of suspended loads, with the highest rates entering from the northeast direction and the lowest rates from the southwest direction. This pattern aligns with the wind rose of Tabas, which illustrates the prevailing wind directions in the region. Additionally, substantial suspended loads are observed in the northwest and north directions. The variations in suspended load discharge reveal that the maximum discharge occurs in the city center of Tabas during the months of June and July 2021. This corresponds to the arid climate conditions of these months, where plant growth is limited, soil cohesion is low, and loose soil particles on the surface are susceptible to wind forces. As a result, these loose particles are easily detached by the wind, contributing to the high levels of suspended load. Regarding the spatial variation of heavy metals in suspended particles, the cumulative concentrations of Mn, Fe, Cu, and Zn are found to be higher in the west, northwest, north, and west directions, respectively. This suggests that these heavy metals are transported and deposited in specific areas within Tabas due to the prevailing wind patterns. In terms of temporal variation, the highest concentrations of Mn and Fe in suspended particles are observed in April 2021, predominantly in the northeast and west directions, respectively. On the other hand, the highest concentrations of Cu and Zn are found in May 2021, with the southwest and northeast directions being the primary deposition areas for each metal, respectively. These findings highlight the spatial and temporal dynamics of suspended load and heavy metal deposition in Tabas, emphasizing the influence of wind patterns and climatic conditions on these processes. Understanding these variations is crucial for assessing the potential risks associated with heavy metal contamination and implementing appropriate mitigation measures in the region. Conclusion The results of this research showed that most contents of the suspended load are entered from the northeast direction into Tabas. In addition, the spatial variation of heavy metals indicated that the concentrations of studied heavy metals (Mn, Fe, Cu, and Zn) in suspended particles, especially in the western, northwestern, and northern in spring, are very high and they can cause carcinogenic effects on human life. Therefore, the management practices should be mostly made in these directions to control or reduce soil erosion and reduce its damage effects. [ABSTRACT FROM AUTHOR]

An accurate assessment of sediment transport can assist land and resource managers in any region. The primary objective of this study was to develop a distributed hydrological model for calculating rainfall-runoff coupled with sediment transport to provide a practical method for estimating sediment transport in western Heilongjiang Province, China. The Alun River Basin, which has typical meteorological and hydrological characteristics of western Heilongjiang Province, was chosen as the study area. A sediment transport calculation module was developed based on physically based formulas for the suspended load and bedload, which was coupled with a numerical model of the physical distributed rainfall-runoff process. The model’s ability was validated by comparing the sediment sampling survey results of the particle size group distribution (PSGD) in the flow and the corresponding value of the model calculation results for a control case. The root mean square error ( RMSE ) and the mean absolute error ( MAE ) were mostly 15%. The results provide a basis for the assessment of sediment transport and the development of a numerical platform for modeling hydrological processes coupled with land surface processes in western Heilongjiang Province, China.

Quadrotors have been utilized in a variety of applications where the payload needs to be transferred from one location to another, such as in mine detection, load delivery through hazardous environments, or locations that are inaccessible to ground vehicles. In these applications, the payload will be suspended underneath the vehicle and is subjected to large oscillations due to external disturbances or the acceleration of the vehicle itself. In this article, the most recent advancements in controlling the quadrotors vehicles with suspended loads are presented including control algorithms and techniques to implement these controllers. These techniques include the hardware and sensors besides the testing techniques for the developed control algorithms. [ABSTRACT FROM AUTHOR]

A volume-filtered Large Eddy Simulation (LES) of oscillatory flow over a mobile rippled bed is conducted using an Euler–Lagrange approach. The modeling is done to complement the experimental work, which shows quasi-steady state ripples in a sand bed under oscillatory flow, as observed in unsteady marine flows over sedimentary beds. Simulations approximate the experimental configuration with a sinusoidal pressure gradient driven flow and a sinusoidally shaped rippled bed of particles. The LES equations, which are volume-filtered to account for the effect of the particles, are solved on an Eulerian grid, and the particles are tracked in a Lagrangian framework. A Discrete Particle Method (DPM) is used, where the particle collisions are handled by a soft-sphere model, and the liquid and solid phases are coupled through volume fraction and momentum exchange terms. Comparison of the numerical results to the experimental data show that the LES-DPM captures the mesoscale features of the system. The simulations reproduced the large scale shedding of vortices from the ripple crests observed in experiments. Likewise, the simulations exhibited quantitative agreement between the wall-normal flow statistics, and qualitative agreement in ripple shape evolution and sand particle entrainment behavior above the fluid-bed interface. The numerical data provide insight into the formation of shear layers and eddies within the flow field above and through the ripple and their influence on the particle transport and the dilation of the ripple mobile layer thickness during an oscillatory period. The resolution of flow structures within the particle bed in the LES-DPM simulations make the framework a unique tool for investigating ripple driven sediment transport and distribution of momentum over the ripple. [ABSTRACT FROM AUTHOR]

Water systems contain fine sediment as a natural phenomenon. The main cause of ecological deterioration is undesirable fine sediment. Fine sediment comprises inorganic particles of sand, silt, and clay that are less than 2 mm in diameter. Fine sediment is considered to be pollutant in water bodies (rivers, streams, lakes, and reservoirs). Sediment has various channel and nonchannel sources. Fine sediment can alter the hydraulics of rivers and their morphology. It has detrimental effects on reservoir storage and function, can degrade the food chain, and affects the reproduction of aquatic animals, which ultimately affects river ecosystems. The deposition of fine sediment renders waterways difficult to navigate and hinders recreational uses. It degrades the water quality for drinking purposes, wildlife, and affects the land surrounding the bodies of water. The intrusion of fine sediment is a global problem, and with time, researchers will understand the effects on biological and physical processes. Comprehension may help scientists minimize the effects of fine sediment on river ecosystems by considering various disciplines such as ecology, hydraulics, fluvial geomorphology, and hydrochemistry. Many researchers have investigated fine sediment in rivers. This paper reviews the literature, focusing on the consequences of intrusion on the river ecosystem, river health, and associated hydraulic parameters. The study of FSI is a major application in applied environmental science. It is applied to gain as complete an understanding of the physical and biological processes as possible. It has been applied to estimate the trap efficiency and to determine the live storage capacity of reservoirs. Excess fine sediment is a primary reason for the failure of water bodies, so it is important to control it and maintain necessary fluid properties such as viscosity, specific weight, and the optical properties of water. Proper control of fine sediment in bodies of water maintains both the survival and growth of plants, and the food chain of aquatic animals. It is important to control excess fine sediment to avoid turbidity in water. In brief, the topic has applications in various fields such as evaluating river health, live reservoir capacity, growth of flora and fauna, and water quality standards. [ABSTRACT FROM AUTHOR]

Bedload is rarely measured in Indian rivers. It is recommended that 5% of suspended load can be taken as bedload in the absence of measured bedload. The present study validates this by direct physical measurement of bedload using the Helley–Smith sampler in an ephemeral mountain stream of Gujarat, India. It was observed that, on an average, the bedload formed 3.97% of the suspended load. The measured bedload flux was 1.02 tonnes/ day. To overcome the need and dependability on actual physical bedload measurement, a bedload rating curve against specific discharge was developed to predict the bedload rate in the study reach. Few prominent existing bedload equations selected from the literature were tested against the measured bedload, which over-predicted the bedload transport rate with a discrepancy ratio greater than 2 and RMSE 2.4–48. A calibration coefficient ξ = 0.00167 was introduced in the widely used Recking (2013) equation for the study reach resulting in an improvement of the coefficient of variation as 1.92 and RMSE as 1.35. [ABSTRACT FROM AUTHOR]

The study is to evaluate the total sediment transport (suspended and bed load) in a Mediterranean river (Bellah, Tipaza, Algeria). To understand this study, we based our analysis on hydrometric data related to the instantaneous discharge and to the concentration of suspended sediment, over a period of 33 years (from 1974/75 to 2006/07). The results show that a good correlation between the suspended sediments and water discharge. The exponent b of our model is equal to 1.38, a value close to those found by researchers who worked in semi-arid region. The suspended sediment transport is about 610 t km-2 year-1. This value is comparable to those found in other regions with similar hydrologic regimes. The bed load is about 170 t km-2 year-1 for τ0 = γ × I × Rh t km-2 year-1 and it is about 115 t km-2 year-1 for τ0 = 0.7×γ × I × Rh. The total sediment transport is estimated at 725 t km-2 year-1 if we take into account the corrective coefficient of roughness in the bed of the wadi and equal to 780 t km-2 year-1 in other direction. To better judge our results, we compared them with those obtained by the relationship Tixeront which remains the most used for estimating the specific degradation in the basins of the Maghreb. The value obtained by the relation of Tixeront is slightly below our own values, but it is permissible to say that the results are of the same order of magnitude. This slight difference can be explained by the introduction of the amount of sediments carried in the determination of the specific erosion of the watershed rates. [ABSTRACT FROM AUTHOR]

With the operation of six cascade reservoirs, the flow regime and sediment discharge of the Lancang River have changed greatly. The changes of runoff and suspended load have attracted extensive attention. The hydrological data of Gajiu and Yunjinghong stations in Lancang River from 1964 to 2019 were analyzed by using wavelet analysis, double mass curve and abrupt change analysis. The temporal trends in runoff and suspended load were evaluated. Results revealed that the reduction of suspended load was much more profound than the change of runoff. There was a slight downward trend in annual runoff due to climate change. After the completion of Xiaowan and Nuozhadu reservoirs, the proportion of runoff in flood season decreased by 22.64 and 30.75%, respectively. Wavelet analysis was used to reveal the characteristics of runoff evolution. With the operation of reservoirs, suspended load showed abrupt changes in 1993 and 2008. The amount of suspended load during 2009–2019 decreased by 95.47–98.78% compared with that before the reservoir construction. This paper presents the latest quantitative study on the temporal variation of runoff and suspended load since the completion of Xiaowan and Nuozhadu reservoirs, which is of great importance for guiding the operation of reservoirs and maximizing the value of the whole Lancang-Mekong River basin. HIGHLIGHTS Variations of runoff and suspended load during 1964–2019 in Lancang River were first quantified in detail after Xiaowan and Nuozhadu reservoirs were completed.; The total amount of runoff was dominated by climate change, while reservoir construction mainly influenced the annual process of runoff.; Suspended load exhibited abrupt changes in 1993 and 2008 and the reduction reached 95–99% after the reservoir construction.;

Abstract Sedimentary structures in ancient deposits are clues to reconstruct past geohazards. While parallel lamination formed by plane beds is one of the most common sedimentary structures in event deposits such as turbidites, the formative conditions for plane beds remain unclear. In the literature, two types of plane beds (upper and lower plane beds) exist and are supposed to develop under different shear stresses, particle sizes, and flow regimes. Here, we present new phase diagrams based on the compilation of existing data regarding formative hydraulic conditions for plane beds to clarify the formation processes associated with the two types of plane beds. The diagrams indicated that the data form two separate populations and the gap between them corresponds to the threshold condition of the particle entrainment into suspension. Lower plane beds form when sediment particles move only as bed load. This phase space can be discerned from fine sand to gravel and differs from the conventional view in which the formation of the lower plane bed is limited to grain sizes above 0.7 mm. In addition, our phase diagrams suggest that upper plane beds appear under conditions of the active suspended load. Our analyses demonstrate that the suspended load contributes to the formation of plane beds, whereas other mechanisms can also produce fine-grained plane beds in flows with low bed shear stress. Thus, the results of this study suggest that the existing interpretations on fine-grained parallel lamination such as Bouma’s Td division need to be reconsidered. The bedform phase diagrams newly established in this study will be useful for estimating the flow conditions from the geologic records of event beds.

A method is proposed to estimate the swing state of a suspended payload in multirotor drone delivery scenarios. Starting from the equations of motion of the coupled slung load system, defined by two point masses interconnected by a rigid link, a recursive algorithm is developed to estimate cable swing angle and rate from acceleration measurements available from an onboard Inertial Measurement Unit, without the need for extra sensors. The estimation problem is addressed according to the Extended Kalman Filter structure. With respect to the classical linear formulation, the proposed approach allows for improved estimation accuracy in both stationary and maneuvering flight. As an additional contribution, filter performance is enhanced by accounting for aerodynamic disturbance force, which largely affects the estimation accuracy in windy flight conditions. The validity of the proposed methodology is demonstrated as follows. First, it is applied to an octarotor platform where propellers are modeled according to blade element theory and the load is suspended by an elastic cable. Numerical simulations show that estimated swing angle and rate represent suitable feedback variables for payload stabilization, with benefits on flying qualities and energy demand. The algorithm is finally implemented on a small-scale quadrotor and is investigated through an outdoor experimental campaign, thus proving the effectiveness of the approach in a real application scenario.

In natural rivers, sediment heterogeneity and flow variability control the diversity of transport modes that occur. Although these different modes contribute to the total sediment transport, a law extending from bed load to suspended load that is, relevant for a wide range of sediment mixtures and flow conditions is lacking. Besides, a transport‐limited assumption is often made in modeling of fluvial morphodynamics and thus potentially misses under‐/over‐capacity regimes associated with a particular range of grain sizes and hydraulic conditions. We present a Multi Grain‐Size Total Load model based on widely accepted concepts of sediment transport and developed within the transport length framework in combination with an erosion‐deposition formulation. The new transport length model captures the diversity of transport modes as a physical continuum. Transport capacities for single or bimodal grain sizes are reasonably predicted when compared to published data and scale with the bed shear stress through a continuously varying exponent linked to the characteristic transport height. Modeled transport lengths extend over several orders of magnitude at given flow conditions. Extremely long distances suggest that suspended transport is probably never at capacity. The model can be extended to populations of various grain sizes with a threshold of motion corrected from hiding‐exposure. However, further experimental constraints are needed to better describe entrainment and saltation in strongly heterogeneous bed load transport. The new theoretical formalism we introduce paves the way for a Multi Grain‐Size Total Load Sediment Transport model that includes the variety of transport modes in both non‐stationary and stationary regimes. Plain Language Summary: In natural rivers, flow variability and sediment heterogeneity affect how sediment grains are transported. Whether grains move close to the bed or higher in the water column, they all contribute to the total sediment transport as bed load and suspended load, respectively. However, a unique law that predicts the total amount of sediment that can be transported by a river for a wide range of sediment mixtures and flow conditions is lacking. Besides, in modeling of fluvial morphodynamics, the river is often assumed at capacity, meaning that it carries the maximum sediment load it can, and thus under‐/over‐capacity regimes are potentially missed. We present a Multi Grain‐Size Total Load model, built by bringing together widely accepted concepts of sediment transport, that includes the variety of transport modes in both capacity and under‐/over‐capacity regimes. The two main components of this model are: (a) the transport length defined as the distance over which sediments are transported and (b) the erosion‐deposition formulation that explicitly describes the transfer of sediment from the sediment bed to the above water column, and conversely. While the new transport length model captures the transport from bed load to suspension continuously, the erosion‐deposition model applies to several grain sizes. Key Points: Emergence of a continuous description of sediment transport using the transport length model and the erosion‐deposition frameworkUnified theory of sediment transport encompassing the diversity of transport modes such as bed load and suspended loadModel applicable to both non‐stationary and stationary regimes while showing that transport in suspension is likely never at capacity [ABSTRACT FROM AUTHOR]

Sedimentation is almost a serious problem for reservoir dams due to loss of storage, malfunction of bottom intakes, corrosion, and damage to power generators, increased flood risk, water quality degradation, and other environmental degradation problems. There are some methods of sediment removal from the reservoir, such as dredging and flushing. The above techniques are not feasible for all reservoirs due to high cost and low efficiency. In this paper, a new sediment extractor referred hereafter as Dam-Type Sediment Excluder (DTSE) is introduced. The self-cleaning DTSE excludes suspended sediment from the river flow upstream of the reservoir and then bypasses the river downstream of the reservoir. The efficiency of the proposed DTSE was examined under different excluding flow rates, opening heights, inlet flow Froude numbers, and sediment concentrations. This research also investigates the influence of suspended- sediment concentration profile on the model efficiency. The results indicate that the efficiency of the DTSE is highly sensitive to the flow velocity and the middle intake location and height. The maximum extracted efficiency of the model was found to be about 40%, while the average optimal efficiency was 26%. [ABSTRACT FROM AUTHOR]

Sediment transport in tidal estuaries is complex and changeable. How to scientifically classify the forms of sediment transport and evaluate its impact on channel sedimentation is the key to clarify the source of sediments deposited in the channel and formulate channel siltation reduction measures. In this paper, a new method identifying three forms of sediment transport, that is the bed load (BL), the suspended load ( SL) and the bed-suspended conversion load (BSCL), was proposed based on analyzing the grain size of surficial bed sediment ( SBS) and near bottom suspended sediment (NBSS) . The sediment samples were collected along the Deepwater Navigational Channel (DNC) in the Yangtze Estuary (YE) during the flood and dry seasons of 2015 and 2018, and the contributions of three forms of sediment transport to the channel sedimentation was quantified. The results show that the upper turning point of grain size cumulative frequency curve is able to well represent the sediment transport form transition from BL to SL. There exists a significant sediment exchange between SBS and NBSS at the South Channel ( SC) as well as the North Passage (NP) of YE. The sediment transport in DNC are not only in forms of BL and SL, but also in BSCL, which accounts for the proportion of 50% to 60% of the channel sedimentation. The contribution of BL to the channel deposition at SC segment of DNC in flood and dry season are 36% and 26% respectively, which is higher than that of SL occupying 6% and 13% . In contrast, the contribution of SL to the channel deposition at NP segment of DNC ranges from 44% to 48%, which is much higher than that of BL only accounting for 3% to 6% . The proposed method based on the grain size analysis provides a new sight on understanding the characteristics of sediment movement in tidal estuary and identifying the source of sediments deposited in the channel. [ABSTRACT FROM AUTHOR]

Sediment transport is one of the most important issues in river engineering. In this study, the capability of the Kernel Extreme Learning Machine (KELM) approach for predicting the river daily Suspended Sediment Concentration (SSC) and Discharge (SSD) was assessed. Three successive hydrometric stations of Mississippi river were considered and based on the sediment and flow characteristics during the period of 2005–2008. Several models were developed and tested for SSC and SSD modeling. For improving the applied model efficiency, two post-processing techniques, namely Wavelet Transform (WT) and Ensemble Empirical Mode Decomposition (EEMD), were used. Also, two states of modeling based on stations' own data (state 1) and previous stations' data (state 2) were considered. The single and integrated KELM model results comparison indicated that the integrated WT and EEMD-KELM models resulted in more accurate outcomes. Results showed that data processing with WT was more effective than EEMD in increasing the models' efficiency. Data processing enhanced the models' capability by up to 15%. The results showed that the state 1 modeling led to better results, however, using the integrated KELM approaches the previous stations data could be applied successfully for SSC and SSD modeling when the stations' own data were not available. HIGHLIGHT The suspended sediment concentration (SSC) and suspended sediment discharge (SSD) were predicted via artificial intelligence approach in successive hydrometric stations. The data pre-processing impacts on models' efficiency improvement was assessed. The sensitivity analysis showed the most effective subseries was obtained from pre-processing models.;

Because of multifunctional weirs installed as part of large river regulation works in Korea, water quality problems have arisen from environmental changes in tandem with decreased flow rates. However, there has been limited research into the green algae removal effect, water quality improvement in congested waters, dam and weir operations, and consequential riverbed changes. Studies regarding outflow in a basin, the application and development of sediment load output analysis methods, feasibility of related dam operations, and riverbed patterns have been separately performed. However, basins and rivers should be analyzed by an integrated method instead of an individual one. Therefore, in the present study, the effect of congestion on a river connected to a dam/weir and estuary bank was analyzed based on climate change scenarios HadGEM3-RA RCP 4.5 and 8.5, with the aim of integrating individual studies using watershed and river models. Flow was controlled by dam- and weir-related discharge simulations. Variations in the riverbed caused by the transfer of suspended load in the downstream region were analyzed for both long and short durations. The results of this analysis suggest that given future climate change scenarios, the width of the river and riverbed variations in the riverbed are expected to rise. HIGHLIGHTS Impact of long-term geometric variation in rivers.; Analysis of climate change scenarios.; Integrate watershed and river.; Variations in the riverbed for both long and short durations.; Analysis of both watershed runoff and sediment transport in a river.;

River sediment budgets are prepared globally, under different conditions and requirements. This paper proposes a general methodology for sediment budgeting – the River Sediment Budget Approach (RSBA), to demonstrate the challenges and opportunities involved in establishing a sediment budget. The methodological approach focuses on the bedload, suspended sediment load as well as changes in the river bed and morphology. Four approaches are provided for sediment budgeting, which can be used individually or in combination and are selected based on the time scale and data availability. If measurement data is available or can still be undertaken, a (i) field-based approach is selected. Specifically, the morphological changes or data required for formulas can be gathered using a (ii) GIS-based approach. When calculations are carried out without measured data, a (iii) formula-based approach is pursued. Due to the numerous budgets already conducted and sediment data already measured, an approach dependent on (iv) literature data and estimations can also be considered. Due to the complexity of sediment dynamics in rivers, strict rules are not beneficial in sediment budgeting and, to avoid misinterpretation, it is essential to validate the results. • A budget approach (RSBA) with a hierarchical decision matrix. • Sediment budgets as a methodology to budget suspended sediment and bedload at different temporal and spatial scales. • Opportunities for sediment budgeting with weak datasets. [ABSTRACT FROM AUTHOR]

Sedimentary structures in ancient deposits are clues to reconstruct past geohazards. While parallel lamination formed by plane beds is one of the most common sedimentary structures in event deposits such as turbidites, the formative conditions for plane beds remain unclear. In the literature, two types of plane beds (upper and lower plane beds) exist and are supposed to develop under different shear stresses, particle sizes, and flow regimes. Here, we present new phase diagrams based on the compilation of existing data regarding formative hydraulic conditions for plane beds to clarify the formation processes associated with the two types of plane beds. The diagrams indicated that the data form two separate populations and the gap between them corresponds to the threshold condition of the particle entrainment into suspension. Lower plane beds form when sediment particles move only as bed load. This phase space can be discerned from fine sand to gravel and differs from the conventional view in which the formation of the lower plane bed is limited to grain sizes above 0.7 mm. In addition, our phase diagrams suggest that upper plane beds appear under conditions of the active suspended load. Our analyses demonstrate that the suspended load contributes to the formation of plane beds, whereas other mechanisms can also produce fine-grained plane beds in flows with low bed shear stress. Thus, the results of this study suggest that the existing interpretations on fine-grained parallel lamination such as Bouma's Td division need to be reconsidered. The bedform phase diagrams newly established in this study will be useful for estimating the flow conditions from the geologic records of event beds. [ABSTRACT FROM AUTHOR]

Multi-rotor flying vehicles (MRFVs) are increasingly becoming the preferred means of transportation in various civilian and military applications, such as mine detection, reconnaissance missions, agriculture, and load transfer to areas inaccessible to ground vehicles. In these applications, the payload is suspended underneath the vehicle and subjected to large oscillations because of external disturbances or the vehicle's acceleration. This study proposes an anti-swing controller (ASC) based on time-delayed feedback of the load swing angles to be implemented in MRFVs with suspended load and operated by a PX4 autopilot. The PX4 autopilot is now widely used in commercial drones. The implementation of the proposed ASC does not require any modifications to the original PX4 firmware because it adds additional displacements to the original trajectories of MRFVs. The effectiveness of the ASC is evaluated by simulating a quadrotor as an example of MRFVs with different flight conditions. [ABSTRACT FROM AUTHOR]

Estimating the effect of sediment transport, especially suspended load, is important in river planning and management. The aim of this study was to investigate the effect of suspended sediment load on the roughness coefficient and the intensity of flow turbulence in Haraz, Rostamabad and Beheshtabad Rivers. In order to better understand these relationships, the geometric characteristics of the sections, the flow velocity and the suspended load were measured in different sections of these rivers. Then shear stress, Manning coefficient and Von karman coefficient were calculated using related equations in each section. The intensity of turbulence was also determined by measuring velocity fluctuations. The study of the effect of suspended load on roughness coefficient and Van Carmen coefficient showed that in most sections roughness coefficient and Van Carmen coefficient have decreased due to the presence of suspended load. In Haraz, Rostamabad and Beheshtabad Rivers, the ratio of roughness coefficient in the presence of suspended load to roughness coefficient without suspended load was 0.9, 0.94 and 0.6, respectively. The results of this study showed that the turbulence intensity distribution is independent from the flow rate and the distribution is always convergent and its maximum value occurred not in the bed but above the bed. Besides, the distribution of turbulence intensity in the presence of suspended load in gravel-boulder rivers is convergent and can be analyzed based on the boundary layer equation. Quadrant analysis was performed on the dominant events at three flow depths. In the areas close to the bed, the predominant phenomena were inward, outward and ejection, respectively, and the contribution of the sweeping event in this section was negligible.

Quadrotor flying vehicles with suspended loads have a lot of applications, such as mine detection and transferring loads for delivery, or through places where ground vehicles cannot reach. In these applications, the payload will be suspended underneath the vehicle and it is subjected to large oscillations due to external disturbances or the acceleration of the vehicle itself. These oscillations add additional forces and moments to the quadrotor, and this deteriorates its performance and stability. In this paper, we developed a hardware-in-the-loop (HIL) simulation platform for a quadrotor with a suspended load system using Gazebo. The developed platform can be used to understand the dynamics of the system and design control systems to suppress the oscillation of the suspended load. An anti-swing controller that is based on time-delayed feedback of the load swing angles is implemented in the designed HIL environment to show the usefulness of the newly developed system and the effectiveness of the anti-swing controller. [ABSTRACT FROM AUTHOR]