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yes / A two dimensional (2D) RNG k-ε sediment model including the effects of secondary currents is developed to simulate sediment transport and bed deformation in rivers with continuous bends. Nonuniform suspended and bedload sediment transports and variation of effective bed material size distribution are included in the model. A semi-coupled scheme for sediment model is proposed, which can be used for simulating both the long- and short-term sediment transport whenever riverbed changes. The model is applied to simulate the flow and sediment transport in the Shapotou reservoir in the upper reach of the Yellow River which is a typical natural river reach with continuous bends. River bed deformations caused by suspended and bedload sediment transport are investigated. Good agreement between the numerically simulated results and the field measurements is obtained, indicating that the model is capable of simulating the sediment transport and predicting the bed deformation of rivers having continuous bends with reasonable accuracy. / the Major Research Plan Project, National Natural Science Foundation of China(Grant No.: 91230111 and 51279071); National Key BasicResearch Development Program of China (973 Program, Grant No.: 2010CB429002);Project of Science and Technology of Colleges in Ningxia, China (Grant No.:NGY2012097)

Yes / This study investigated the impact of sedimentation on rainwater storage system using a case study at the Ikorodu area of Lagos state, a rural area in Nigeria. In this investigation, the proportions of Escherichia coli (E. coli) that were settleable (due to sedimentation) and those that were at the free phase have been studied. Water samples were collected from different depths in the inspected rainwater storage tank at two different periods (i.e. rainy and dry periods) for 20 days. The samples collected from these periods have been analysed for physical and microbial measures before passing it through the serial filters with pore sizes of 500 μm, 100 μm, 10 μm and 1.5 μm to measure the retained particle mass. From the results, it was observed that: (1) the water quality at the free-phase zone was better than that at the tank’s bottom; (2) the settleable bacteria rapidly sinked to bottom; (3) the correlation of turbidity, E. coli and total suspended solids (TSS) for all the rain events showed a relatively high Pearson’s coefficient of 0.9 to one another; and (4) over 70% of settling TSS occurred within first 36 hours. Finally, it has been found that the physical sedimentation process can significantly reduce the microbial measures.

Yes / This paper reviews existing studies relating to the assessment of sediment concentration profiles within various flow conditions due to their importance in representing pollutant propagation. The effects of sediment particle size, flow depth, and velocity were considered, as well as the eddy viscosity and Rouse number influence on the drag of the particle. It is also widely considered that there is a minimum threshold velocity required to increase sediment concentration within a flow above the washload. The bursting effect has also been investigated within this review, in which it presents the mechanism for sediment to be entrained within the flow at low average velocities. A review of the existing state-of-the-art literature has shown there are many variables to consider, i.e., particle density, flow velocity, and turbulence, when assessing the suspended sediment characteristics within flow; this outcome further evidences the complexity of suspended sediment transport modelling.

Sediment, an integral part of rivers and watersheds, is eroded from, stored in, and transported through various watershed components. Rivers often receive sediment in the form of episodic, discrete pulses from a variety of natural and anthropogenic processes, this sediment can be transported downstream along the bed or suspended in the water column. Most sediment measurements are focused on the component suspended in the water column. Recent advances in data collection techniques have substantially increased both the resolution and spatial scale of data on suspended sediment dynamics, which is helpful in linking small, site-scale measurements of transport processes in the field with large-scale modeling efforts. Part of this research evaluates the accuracy of the latest laser diffraction instrument for suspended-sediment measurement in rivers, LISST-SL2 for measuring suspended sediment concentration (SSC), particle size distribution (PSD), and velocity by comparing to concurrent physical samples analyzed in a lab for SSC and PSD, and velocity measured using an acoustic Doppler current profiler (ADCP) at 11 sites in Washington and Virginia during 2018-2020. Another part of this work employs a 1-D river network, bed material transport model to investigate the magnitude, timing, and persistence of downstream changes due to the introduction of sediment pulses in a linear river network. We specifically focus on comparing bed responses between mixed and uniform grain size sediment pulses. Then the model capability is utilized to explore the control of hydrograph structure on debris flow sediment transport through a more complex river network at different time horizons. Another part of this work investigates the effect of differences in spatial distribution of debris flow sediment input to the network by analyzing corresponding tributary and mainstem characteristics. Based on an extensive dataset, our results highlight the need for a correction of the raw LISST-SL2 measurements to improve the estimation of effective density and particle size distribution with the help of a physical sample. Simulation results from the river network model show that bed response is primarily influenced by the sediment-pulse grain size and distribution. Intermediate mixed-size pulses are likely to have the largest downstream impact because finer sizes translate quickly and coarser sizes (median bed gravel size and larger) disperse slowly. Furthermore, a mixed-size pulse, with a smaller median grain size than the bed, increases bed mobility more than a uniform-size pulse. While investigating the hydrologic control on debris flow simulation, this study finds that differences between transport by a 30-year daily hydrograph and simplified hydrographs were greatest in the first few years, but errors decreased to around 10% after 10 years. Our simulation results highlight that the sequence of flows (initial high/low flow) is less important for transport of finer sediment. We show that such network-scale modeling can quantitatively identify geomorphically significant network characteristics for efficient transport from tributaries to the mainstem, and eventually to the outlet. Results suggest that watershed area and slope characteristics are important to predict aggradation hotspots in a network. However, to predict aggradation and fluvial geomorphic responses to variations in sediment supply from river network characteristics more confidently, more widespread (in several other river networks) model applications with field validation would be useful. This work has important implications for river management, as it allows us to better predict geomorphically significant tributaries and potential impact on downstream locations, which are important for river biodiversity. Model results lead the way to use of simplified flow hydrographs for different timescales, which is crucial in large-scale modeling as it is often restricted by computational capacity. Finally, given the ability for reliable quantification of a high-resolution time-series of different suspended-sediment characteristics, in-stream laser diffraction offers great potential to advance our understanding of suspended-sediment transport. / Doctor of Philosophy / Rivers receive sediment from different natural and human sources, and water moves this sediment in various ways. These ways include along the bottom of the stream or suspended in the water. Quantifying suspended sediment in streams is an important step to estimate the threat to riverine environments as suspended sediments not only carry chemicals and pollutants, but also interact with the river bottom to affect the characteristics of streams. Measurement of suspended-sediment concentration and particle-size is critical for many engineering, ecological, and river-structure issues, but obtaining an accurate measurement of sediment quantity in a river is challenging. The recent advancement of a laser diffraction instrument allows us to obtain frequent measurements of suspended-sediment concentration and particle size by volume. We applied the most recent such instrument at 11 sites in Washington and Virginia during 2018-2020, along with concurrent water samples to measure suspended-sediment concentration and particle size by mass in a laboratory. Our analysis suggests that at least one supporting physical mass measurement be obtained to improve the estimation from laser measurement. Beside this site-scale measurement, we apply a large-scale river network model to estimate how sediment moves along the bed of rivers at large spatial extents. We simulate how this added sediment results in downstream changes in the amount of sediment in the river channel. We compare observed changes in the elevation of the stream bottom and sediment accumulation rates in a downstream lake to model results. Then we investigate the magnitude, timing, and persistence of downstream changes due to the introduction of added sediment by comparing the changes against a baseline condition (without the added sediment). We find that the added sediment that is half as large as on the river bottom and with a range of sizes are likely to affect the largest downstream changes because smaller sizes move quickly and larger sizes move slowly. Furthermore, added sediment that is smaller than on the river bottom and with a range of sizes help more sediment on the river bottom move than if that sediment addition all had the same particle size. We also employ this model to explore the effect of flow variation and river characteristics on sediment movement. Comparing between a 30-year flow record and simplified flow records, we show that results from simplified flow records vary initially, but errors decrease after 10 years. That is, both flow records result in similar sediment movement in the long-term. In terms of aggradation from added sediment, results show that the characteristics of elevation change of the river bottom play a vital role along with the contributing landscape area. This work has important implications for river management, as it not only allows us to accurately measure suspended sediment with an advanced instrument, but also better understand how rivers and aquatic habitat are affected by variations in added sediment.

Yes / Based on the Lagrangian approach, this study proposes a random displacement model (RDM) to predict the concentration of suspended sediment in vegetated steady open channel flow. Validation of the method was conducted by comparing the simulated results by using the RDM with available experimental measurements for uniform open-channel flows. The method is further validated with the classical Rouse formula. To simulate the important vertical dispersion caused by vegetation in the sediment-laden open channel flow, a new integrated sediment diffusion coefficient is introduced in this study, which is equal to a coefficient multiplying the turbulent diffusion coefficient. As such, the RDM approach for sandy flow with vegetation was established for predicting the suspended sediment concentration in low-sediment-concentration flow with both the emergent and submerged vegetation. The study shows that the value of for submerged vegetation flow is larger than that for emergent vegetation flow. The simulated result using the RDM is in good agreement with the available experimental data, indicating that the proposed sediment diffusion coefficient model can be accurately used to investigate the sediment concentration in vegetated steady open channel flow. / National Natural Science Foundation (No. 51439007, 11672213, and 11872285); Open Funding of State Key Laboratory of Water Resources and Hydropower Engineering Science (WRHES), Wuhan University (Project No: 2018HLG01)

Yes / Ice cover formed on an alluvial channel can significantly alter the flow characteristics, such as the vertical distributions of streamwise velocity and shear stress, and hence the water and sediment transport process. The vertical profile of the suspended sediment concentration in the ice-covered alluvial channels with steady uniform flows is investigated in this study. To calculate the suspended sediment concentration, we are based on the Schmidt O’Brien equation and deduce an analytical model that employs an existing eddy viscosity model and a modified formula of the sediment fall velocity considering the common effects of the upper and lower boundaries. The proposed analytical model is then validated by using available experimental data reported in the literature. The predicted accuracy of the proposed model is evaluated through error statistics by comparing to previous modeled results. The relative concentration profiles of the suspended sediment are subsequently simulated by applying the validated analytical model with different characteristic parameters. Results show that the relative concentration decreases with the increase of both the ice cover roughness and the sediment fall velocity. The uniformity of the relative concentration distribution is closely related to the value of the proportionality parameter σ, revealing the physical mechanism that the more prominent the turbulent diffusion effect is, the more uniform the relative concentration profile is. / This work was supported by the National Natural Science Foundation of China (grant 604 numbers 52020105006 and 11872285) and the Open Funding of State Key Laboratory of Water Resources and Hydropower Engineering Science (WRHES), Wuhan University (Project number 2018HLG01).

The Diploma thesis deals with the topic of conditionally suspended sentence of imprisonment as a separate type of punishment which is not considered merely as a variation of an unconditional imprisonment sentence. It analyses the individual elements of this institute, its history and development, the conditions of imposing and methods of termination. It also includes a comparison with foreign legislation that should bring suggestions for a better and more efficient execution of conditionally suspended sentence of imprisonment. The thesis is divided into eight chapters. The first chapter deals with general knowledge of conditionally suspended sentence of imprisonment as an alternative punishment and its legal nature. In the second chapter is outlined the historical development of the institute both in the world and in the territory of Czechoslovakia, respectively the Czech Republic. The third chapter is a major part of the thesis and describes the conditions under which conditionally suspended sentence of imprisonment may be imposed, as well as examining the probation period, adequate restraints and adequate duties or compensation for the damage or detriment caused by the offense, or the unjust enrichment gained by the crime. Following chapter relates to the decision on conditionally suspended...

Trotz aller technischen Weiterentwicklungen in der Vergangenheit unterscheiden sich moderne elektronische Tachymeter in ihrer Grundkonstruktion nicht wesentlich von ihren analogen Vorgängern. Ihnen allen ist gemeinsam, dass eine Visur um den Nadir nicht möglich ist. Dies bedeutet, dass Punkte, welche sich in einem Zenitwinkelbereich zwischen ca. 170 und 230 gon befinden, nicht direkt gemessen werden können. Gegenstand der vorliegenden Arbeit war daher die Entwicklung eines Systems, mit welchem tachymetrische Messungen auch in einem Zenitwinkelbereich zwischen 170 und 230 gon möglich sind. Das Konzept basiert auf dem aus dem Markscheidewesen bekannten Hängetheodolit. Um Messungen im Bereich des Nadirs durchführen zu können, wird ein Tachymeter ähnlich einem Hängetheodolit in hängender Position montiert. In dieser Position ist der zur Horizontierung dienende interne elektronische Neigungskompensator jedoch nicht funktionsfähig. Die Horizontierung wird daher extern überwacht. Zu diesem Zweck wird das Tachymeter über eine geeignete Aufhängevorrichtung mit einem Neigungssensor verbunden. Die Kombination aus in hängender Position montiertem Tachymeter und externem Neigungssensor wird als Hängetachymeter bezeichnet. Bei der Kombination des Systems mit einem externen Neigungssensor kann eine geringe Abweichung zwischen der Stehachse des Tachymeters und der Lotachse des Neigungssensors fertigungsbedingt nicht vermieden werden. Zur Bestimmung dieser Abweichung wurden geeignete Verfahren entwickelt und auf ihre Genauigkeit untersucht. Die mit dem Tachymeter ermittelten Messwerte werden durch Instrumentenabweichungen beeinflusst und müssen um diese korrigiert werden. Auch sind die Messwerte um die mit dem externen Neigungssensor ermittelte Stehachsenneigung zu korrigieren. Die Achsenabweichungen des Tachymeters müssen in hängender Position bestimmt werden. Es kann nicht generell vorausgesetzt werden, dass diese mit den in aufrechter Position bestimmten Werten übereinstimmen. Zur Steuerung des Hängetachymeters wurde eine Software entwickelt, in welche die Kalibrierung der Sensoren, die Auswertung und Korrektur der Messwerte, deren Speicherung und Weiterverarbeitung sowie der Datenexport integriert wurden. Eine Kombination des Hängetachymeters mit einer Okularkamera ermöglicht die automatische Zielerkennung und -verfolgung nichtsignalisierter Punkte auch bei Messungen nahe dem Nadir. Zur Realisierung eines Autofokus wurde das Hängetachymeter mit einem Schrittmotor kombiniert, welcher über den Fokussierring des Tachymeters die Fokussierlinse bewegt. Eine Autofokusfunktion wurde auf Grundlage des Bildkontrastes entwickelt. Die Kalibrierung der Okularkamera basiert auf einer Modellierung des Abbildungsprozesses durch lineare Funktionen. Hierbei wurde die Abhängigkeit der Kalibrierwerte von der Position der Fokussierlinse (Position des Schrittmotors) aufgezeigt. Die zur optischen Zielerkennung eingesetzten Bildverarbeitungsalgorithmen gliedern sich in eine manuelle Punktanzielung im Bild, die Messung punktförmiger Muster durch Kantendetektion und Ellipsenanpassung und Bildzuordnungsverfahren nach der Methode der kleinsten Quadrate. Um die Leistungsfähigkeit des Hängetachymeters zu bestimmen, aber auch um die Güte der Kalibrierung zu testen, wurden mehrere Genauigkeitsuntersuchungen durchgeführt. Abschließend wurde das Hängetachymeter auch erfolgreich in der Industrievermessung eingesetzt und eine automatische Kalibrierroutine ohne Interaktion des Benutzers entwickelt. Die erreichten Genauigkeiten des Systems liegen im Bereich der Genauigkeiten des eingesetzten Tachymeters. / Despite all technical enhancements in the past modern electronic tacheometers do not differ significantly to their analogue predecessors. All have in common that aiming around the nadir is not possible. This means that points situated in the zenith angle region between ca. 170 to 230 gon cannot be measured directly. Therefore the subject of the present work was the development of a system that makes measurements in the zenith angle region between 170 and 230 gon possible. The concept is based upon the suspended theodolite which is known in mine-surveying. To carry out measurements in the region of the nadir a total station is mounted in a hanging position similar to a suspended theodolite. However the function of the tilt compensator which is used for levelling of the instrument is not supported in this position. Hence inclination is monitored externally. For this purpose the tacheometer is connected to a clinometer by an appropriate suspension arrangement. The combination of a tacheometer mounted in a suspended position and an external clinometer is called suspended tacheometer. Combining the system with an external clinometer a marginal variation occurs between the vertical axis of the tacheometer and the plummet axis of the clinometer due to production conditions. To quantify this variation an appropriate method was developed and its accuracy tested. Measurements conducted by the tacheometer are influenced by the variations of the instrument and must therefore be adjusted. Moreover these measurements must be adjusted by the inclination detected by the external clinometer. The axis variations of the tacheometer must be determined in suspended position. It cannot be generally presumed that these measurements comply with the ones determined in upright position. To actuate the suspended tacheometer a software was developed. This software also offers integrated functions for calibration of the sensors, analysis and adjustment of the measurements and their storage and processing as well as export of data. A combination of the suspended tacheometer with an ocular camera makes automatic target detection and tracking of non-cooperative signals possible also when measuring near the region of the nadir. To realize an autofocus the suspended tacheometer was combined with a stepper motor which moves the focus lens. Based on the image contrast an autofocus function was developed. The calibration of the ocular camera is based on modelling the mapping process by linear functions. Here the dependency of calibration values on the position of the focus lens (position of the stepping motor) was demonstrated. Image processing algorithms used for optical target detection can be divided into manual target detection in the image, measurement of point-shaped patterns by edge detection and ellipse adjustment and image allocation operations (Least squares matching). To determine the efficiency of the suspended tacheometer as well as to test the performance of the calibration several accuracy tests were performed. Also the suspended tacheometer was successfully deployed in industrial surveying. An automatic calibration routine without participation of a user was developed. The achieved accuracies of the system correspond with the accuracies of the inserted tacheometer.