scholarly journals Assessing and Modelling the Interactions of Instrumented Particles with Bed Surface at Low Transport Conditions

2021 ◽  
Vol 11 (16) ◽  
pp. 7306
Author(s):  
Zaid Alhusban ◽  
Manousos Valyrakis
Keyword(s):  
Sediment Transport ◽  
Turbulent Flows ◽  
Particle Transport ◽  
Particle Density ◽  
Probability Distributions ◽  
Low Cost ◽  
Bed Load ◽  
Transport Dynamics ◽  
Field Deployment ◽  
Near Future

Sediment transport at near threshold to low transport stages (below the continuous transport) can still be affected by flow turbulence and its dynamics can benefit from further comprehensive studies. This study uses an instrumented particle embedded with micro electromechanical sensors (MEMS) to allow tracking the motions and forces acting on it, leading to and during its transport. Instrumented particle transport experiments were carried out at laboratory flume under a range of flow conditions. The probability distributions functions (PDFs) of bed load particle instantaneous velocities, hop distances and associated travel times (measured from start to stop of transport) were obtained for all the performed experiments with varying flow rates and particle density. The modelled distributions are useful and enable a deeper understanding of bed load sediment transport dynamics from a Lagrangian perspective. Furthermore, the results analyzed from the instrumented particle (including the particle’s transport mode) were validated using visual particle tracking methods (top and side cameras). The findings of this study demonstrate that for the range of turbulent flows trialed herein, the instrumented particle can be a useful, accessible, and low-cost tool for obtaining particle transport dynamics, having demonstrated satisfactory potential for field deployment in the near future.

Assessing thresholds for fluvial entrainment with instrumented particles

2021 ◽  
Author(s):  
Khaldoon AlObaidi ◽  
Manousos Valyrakis
Keyword(s):  
Sediment Transport ◽  
Turbulent Flows ◽  
River Flow ◽  
Low Cost ◽  
Experimental Studies ◽  
Energy Criterion ◽  
Field Studies ◽  
Incipient Motion ◽  
Sediment Particles ◽  
Sediment Entrainment

<p>Sediment transport is considered to be the governing process in many applications around the fields of geosciences and engineering as well as infrastructure and environment monitoring. Of a special interest to which scientists and engineers have dedicated a lot of time and experimental studies in the last century is the conditions for initiation of sediment entrainment, or incipient motion. In the literature, there are different criteria for determining the conditions that can result in initiation of sediment entrainment. Among these criteria, the impulse (or energy) criterion [1-2] captures the actual physics of sediment entrainment since it accounts for both the magnitude and the duration of the turbulent flow events that can result in initiation of a particle’s motion. The experimental and field studies of incipient motion use relatively expensive tools, like Particle image velocimetry (PIV) or Acoustic Doppler velocimetry (ADV), with indirect methods to determine flow parameters that could be related to predicting sediment entrainment. However, technological developments in recent decades has made it possible to assess sediment entrainment directly. Recently, a number of research studies [3-4] have suggested linking micro-electromechanical system (MEMS) recordings that consist of accelerometers, gyroscopes and magnetometer as well as an internal digital motion processor that are interconnected forming inertial measurement units (IMUs) to the probability of entrainment of individual particles. The particles have been presented provide a direct, non-intrusive, low-cost and accessible method for assessing the probability of entrainment of individual sediment particles rather than inferred using near bed flow diagnostics. In this work, an instrumented particle of 3cm in diameter [5] is used to investigate experimentally the conditions that can result in initiation of sediment entrainment for a range of flowrates that represent the near threshold conditions. The data is used to derive metrics like frequency of entrainment that could be linked to the probability of entrainment of individual sediment particles which could be used as an indicator of the risk of riverbed destabilization based on well-established theories in hydraulic engineering. Additionally, the novelty of this work is explicitly linking the probability of entrainment to the flow hydrodynamics. In addition to that, a stochastic analysis is performed to identify the relevance of certain flow structures (sweeps) to the incipient entrainment of the instrumented particle.</p><p>[1] Valyrakis M., Diplas P., Dancey C.L., Greer K., Celik A.O. (2010). Role of Instantaneous Force Magnitude and Duration on Particle Entrainment. JGR, 115, 1-18.</p><p>[2] Valyrakis M., Diplas P., Dancey C.L. (2013). Entrainment of Coarse Particles in Turbulent Flows: An Energy Approach. JGR- Earth Surf., 118, 42-53.</p><p>[3] Valyrakis, M., Alexakis, A. (2016). Development of a “smart-pebble” for tracking sediment transport. River Flow 2016, MO, USA.</p><p>[4] Al-Obaidi, K., Xu, Y., Valyrakis, M. (2020). The Design and Calibration of Instrumented Particles for Assessing Water Infrastructure Hazards. JSAN, 9, 3, 36.</p><p>[5] Al-Obaidi, K., Valyrakis, M. (2020). A sensory instrumented particle for environmental monitoring applications: development and calibration. IEEE sensors journal (accepted).</p>

Assessing sediment transport energetics with instrumented particles for above threshold of motion turbulent flows

2020 ◽  
Author(s):  
Zaid Al-Husban ◽  
Manousos Valyrakis
Keyword(s):  
Sediment Transport ◽  
Turbulent Flows ◽  
Particle Transport ◽  
Particle Interaction ◽  
Turbulent Channel Flow ◽  
Optimal Operation ◽  
Distribution Functions ◽  
Sensor Data ◽  
Flow Rates ◽  
Test Configuration

<p>Despite the fact sediment transport has been studied for decades, there is still a need to gain a further insight on the nature and driving mechanisms of bed particle motions induced by turbulent flows, for the low transport stages where the particle transport is relatively intermittent. A custom designed and prototyped instrumented particle, embedded with inertial sensors is used herein to study its transport over hydraulically rough bed surfaces. The calibration and error estimation for its sensors is also undertaken before starting the experiments, to ensure optimal operation and estimate any uncertainties.</p><p>The observations and results of this research are obtained from experiments carried out at the University of Glasgow 12 meters long and 0.9 meters wide, tilting and water recirculating flume. The flume walls comprise of smooth transparent glass that enables observing particle transport from the side (also with underwater video cameras) and the bed surface generally is layered with coarse gravel.</p><p>The particle is initially located at the upstream end of the test configuration, fully exposed to the uniform and fully developed turbulent channel flow. The top and side cameras are set in their suitable positions to monitor and study the behaviour of particle motion by capturing the dynamical features of sediment motion and to not interfere with flow field that pushes particle downstream.<span> </span></p><p>Using the sensor data to calculate the kinetic energy for a range of sets of sediment transport experiments with varying flow rates and particle densities, the probability distribution functions (PDFs) of particle transport features, such as particle’s total energy, are generated which give information about particle interaction with the surface bed during its motion. In addition, the effects of different flow rates, particle densities on particle energy are assessed.</p>

scholarly journals The effects of ice and hillslope erosion and detrital transport on the form of detrital thermochronological age probability distributions from glacial settings

2020 ◽  
Author(s):  
Maxime Bernard ◽  
Philippe Steer ◽  
Kerry Gallagher ◽  
David L. Egholm
Keyword(s):  
Sediment Transport ◽  
Particle Transport ◽  
Large Range ◽  
Probability Distributions ◽  
Age Distribution ◽  
Morphological Characteristics ◽  
Transport Processes ◽  
Surface Erosion ◽  
Sediment Particles ◽  
The Impact

<p>The impact of glaciers on the Quaternary evolution of mountainous landscapes remains controversial. While in-situ low-temperature thermochronology offers insights on past rock exhumation and landscape erosion, it also suffers from biases due to the difficulty of sampling bedrocks buried under the ice of glaciers. Detrital thermochronology attempts to bypass this issue by sampling sediments at, e.g. the catchment outlet, that may originate from beneath the ice. However, the age distribution resulting from detrital thermochronology does not only inform on the catchment exhumation, but also on the patterns and rates of surface erosion and sediment transport. In this study, we use a new version of a glacial landscape evolution model, iSOSIA to address the role of erosion and sediment transport by the ice on the form of synthetic detrital age distributions and thus, for inferred catchment erosion from such data. Sediments are tracked as Lagrangian particles that can be formed by bedrock erosion, transported by ice or hillslope processes and deposited. We apply our model to the Tiedemann glacier (British Columbia, Canada), which has simple morphological characteristics, such as a straight form and no connectivity with large tributary glaciers. Synthetic detrital age distributions are generated by specifying an erosion history, then sampling sediment particles at the frontal moraine of the modelled glacier. The detrital ages are represented as synoptic probability density functions (SPDFs).</p><p>A characterization of sediment transport shows that 1500 years are required to reach an equilibrium for detrital particles age distributions, due to the large range of particle transport times from their sources to the frontal moraine. Second, varying sampling locations and strategies at the glacier front lead to varying detrital SPDFs, even at equilibrium. These discrepancies are related to (i) the selective storage of a large proportion of sediments in small tributary glaciers and in lateral moraines, (ii) the large range of particle transport times, due to varying transport lengths and to a strong variability of glacier ice velocity, (iii) the heterogeneous pattern of erosion, (iv) the advective nature of glacier sediment transport along ice streamlines that leads to a poor lateral mixing of particle detrital signatures inside the frontal moraine. Third, systematic comparisons between (U-Th)/He and fission track detrital ages, with different age-elevation profiles and relative age uncertainties, show that (i) the age increasing rate with elevation largely controls the ability to track sediment sources, and (ii) qualitative first-order information about distribution of erosion may still be extracted from thermochronological system with high variable uncertainties (> 30 %). Overall, our distributions in glaciated catchments are strongly impacted by erosion and transport processes and by their spatial variability. Combined with bedrock age distributions, detrital thermochronology can offer a means to constrain the transport pattern and time of sediment particles. However, results also suggest that detrital age distributions of glacial features like frontal moraines, are likely to reflect a transient case as the time required to reach detrital thermochronological equilibrium is of the order of the short-timescale glaciers dynamic variability, as little ice ages or recent glaciers recessions.</p>

scholarly journals The effects of ice and hillslope erosion and detrital transport on the form of detrital thermochronological age probability distributions from glacial settings

2020 ◽  
Author(s):  
Maxime Bernard ◽  
Philippe Steer ◽  
Kerry Gallagher ◽  
David Lundbek Egholm
Keyword(s):  
Sediment Transport ◽  
Particle Transport ◽  
Large Range ◽  
Probability Distributions ◽  
Morphological Characteristics ◽  
Transport Processes ◽  
Surface Erosion ◽  
Sediment Particles ◽  
Time Required ◽  
The Impact

Abstract. The impact of glaciers on the Quaternary evolution of mountainous landscapes remains controversial. Although in situ low-temperature thermochronology offers insights on past rock exhumation and landscape erosion, the methods also suffer from biases due to the difficulty of sampling bedrock buried under glaciers. Detrital thermochronology attempts to bypass this issue by sampling sediments, at e.g. the catchment outlet, that may originate from beneath the ice. However, the age distributions resulting from detrital thermochronology do not only reflect the catchment exhumation, but also the patterns and rates of surface erosion and sediment transport. In this study, we use a new version of a glacial landscape evolution model, iSOSIA, to address the effect of erosion and sediment transport by ice on the form of synthetic detrital age distributions. Sediments are tracked as Lagrangian particles which can be formed by bedrock erosion, transported by ice or hillslope processes and deposited. We apply our model to the Tiedemann glacier (British Columbia, Canada), which has simple morphological characteristics, such as a linear form and no connectivity with large tributary glaciers. Synthetic detrital age distributions are generated by specifying an erosion history, then sampling sediment particles at the frontal moraine of the modelled glacier. An assessment of sediment transport shows that 1500 years are required to reach an equilibrium for detrital particle age distributions, due to the large range of particle transport times from their sources to the frontal moraine. Next, varying sampling locations and strategies at the glacier front leads to varying detrital SPDFs, even at equilibrium. These discrepancies are related to (i) the selective storage of a large proportion of sediments in small tributary glaciers and in lateral moraines, (ii) the large range of particle transport times, due to varying transport lengths and to a strong variability of glacier ice velocity, (iii) the heterogeneous pattern of erosion, (iv) the advective nature of glacier sediment transport, along ice streamlines, that leads to a poor lateral mixing of particle detrital signatures inside the frontal moraine. Finally, systematic comparisons between (U-Th)/He and fission track detrital ages, with different age-elevation profiles and relative age uncertainties, show that (i) the nature of the age-elevation relationship largely controls the ability to track sediment sources, and (ii) qualitative first-order information may still be extracted from thermochronological system with high uncertainties (> 30 %) depending on erosion pattern. Overall, our results demonstrate that detrital age distributions in glaciated catchments are strongly impacted not only by erosion and exhumation but also by sediment transport processes and their spatial variability. Combined with bedrock age distributions, detrital thermochronology offers a means to constrain the transport pattern and time of sediment particles. However, our results also suggest that detrital age distributions of glacial features like frontal moraines, are likely to reflect a transient case as the time required to reach detrital thermochronological equilibrium is of the order of the short-timescale glacier dynamics variability, as little ice ages or recent glaciers recessions.

scholarly journals A Low-Cost Assistive Robot for Children with Neurodevelopmental Disorders to Aid in Daily Living Activities

2021 ◽  
Vol 18 (8) ◽  
pp. 3974
Author(s):  
Roberto J. López-Sastre ◽  
Marcos Baptista-Ríos ◽  
Francisco Javier Acevedo-Rodríguez ◽  
Soraya Pacheco-da-Costa ◽  
Saturnino Maldonado-Bascón ◽  
...  
Keyword(s):  
Neurodevelopmental Disorders ◽  
Low Cost ◽  
Children And Youth ◽  
Proof Of Concept ◽  
Robotic Platform ◽  
Assistive Robot ◽  
Technical Details ◽  
The Impact ◽  
Near Future ◽  
Everyday Living

In this paper, we present a new low-cost robotic platform that has been explicitly developed to increase children with neurodevelopmental disorders’ involvement in the environment during everyday living activities. In order to support the children and youth with both the sequencing and learning of everyday living tasks, our robotic platform incorporates a sophisticated online action detection module that is capable of monitoring the acts performed by users. We explain all the technical details that allow many applications to be introduced to support individuals with functional diversity. We present this work as a proof of concept, which will enable an assessment of the impact that the developed technology may have on the collective of children and youth with neurodevelopmental disorders in the near future.

scholarly journals Relative Transportability for Non-uniform Bed Load Sediment Transport

2018 ◽  
Vol 153 ◽  
pp. 042006
Author(s):  
Li Zhijing ◽  
Li Dazhi ◽  
Liu Xiaobin ◽  
Jin Zhongwu ◽  
Chen Dasong
Keyword(s):  
Sediment Transport ◽  
Bed Load ◽  
Load Sediment

scholarly journals Bacterial Nanocellulose in Dentistry: Perspectives and Challenges

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 49
Author(s):  
Hélida Gomes de Oliveira Barud ◽  
Robson Rosa da Silva ◽  
Marco Antonio Costa Borges ◽  
Guillermo Raul Castro ◽  
Sidney José Lima Ribeiro ◽  
...  
Keyword(s):  
Tissue Repair ◽  
Biomedical Applications ◽  
Low Cost ◽  
Pulp Tissue ◽  
Bacterial Nanocellulose ◽  
Artificial Blood ◽  
Current Trends ◽  
Artificial Blood Vessels ◽  
Near Future ◽  
Dressing Materials

Bacterial cellulose (BC) is a natural polymer that has fascinating attributes, such as biocompatibility, low cost, and ease of processing, being considered a very interesting biomaterial due to its options for moldability and combination. Thus, BC-based compounds (for example, BC/collagen, BC/gelatin, BC/fibroin, BC/chitosan, etc.) have improved properties and/or functionality, allowing for various biomedical applications, such as artificial blood vessels and microvessels, artificial skin, and wounds dressing among others. Despite the wide applicability in biomedicine and tissue engineering, there is a lack of updated scientific reports on applications related to dentistry, since BC has great potential for this. It has been used mainly in the regeneration of periodontal tissue, surgical dressings, intraoral wounds, and also in the regeneration of pulp tissue. This review describes the properties and advantages of some BC studies focused on dental and oral applications, including the design of implants, scaffolds, and wound-dressing materials, as well as carriers for drug delivery in dentistry. Aligned to the current trends and biotechnology evolutions, BC-based nanocomposites offer a great field to be explored and other novel features can be expected in relation to oral and bone tissue repair in the near future.

EFFECTS OF ENVIRONMENT ON GROWING HYDROPONICS MAIZE FODDER USING LOW-COST GREENHOUSE CULTIVATING UNIT FOR LIVESTOCK PRODUCTION.

2021 ◽  
pp. 71-72
Author(s):  
Adamu, B. ◽  
Abdullahi, S. ◽  
Saidu, S. G ◽  
Yustus Sunday Francis
Keyword(s):  
Relative Humidity ◽  
Environmental Factors ◽  
Production System ◽  
Low Cost ◽  
Factors Affecting ◽  
Production Water ◽  
Fodder Production ◽  
Food Requirement ◽  
Greenhouse Cultivation ◽  
Near Future

The term 'Hydroponics' was derived from Greek words 'hydro' means water and 'ponics' means labor. Hydroponic is a modern agricultural technique that uses nutrient solution rather than soil solution for fodder production. As population increases the food demand also increased, the existing system of agriculture will not be able to meet the food requirement in the near future due to environmental challenges in the industry. The major environmental factors affecting the hydroponics production system are; Temperature, relative humidity, and light. The objectives of this studies are to examine the hydroponics greenhouse technologies, impact of environmental factors on hydroponics greenhouse cultivation and challenges of growing on hydroponics greenhouse system. This study revealed that hydroponics greenhouse cultivation is a better option for improved fodder production, water utilization, palatability and digestibility.

scholarly journals Regression analysis between sediment transport rates and stream discharge for the Nestos River, Greece

2013 ◽  
Vol 14 (3) ◽  
pp. 362-370
Keyword(s):  
Sediment Transport ◽  
Suspended Load ◽  
Bed Load ◽  
Regression Curve ◽  
Degree Polynomial ◽  
Stream Discharge ◽  
Nestos River ◽  
Polynomial Curve ◽  
Load Transport ◽  
Bed Load Transport

Systematic measurements of sediment transport rates and water discharge were conducted in the Nestos River (Greece), at a place located between the outlet of Nestos River basin and the river delta. This basin area is about 838 km2 and lies downstream of the Platanovrysi Dam. Separate measurements of bed load transport and suspended load transport were performed at certain cross sections of the Nestos River. In this study, relationships between sediment transport rates and stream discharge for the Nestos River are presented. A nonlinear regression curve (4th degree polynomial curve; r2 equals 0.62) between bed load transport rates and stream discharge, on the basis of 63 measurements, was developed. In addition, a nonlinear regression curve (5th degree polynomial curve; r2 equals 0.95) between suspended load transport rates and stream discharge, on the basis of 65 measurements, was developed. The relatively high r2 values indicate that both bed load transport rates and, especially, suspended load transport rates can be predicted as a function of the stream discharge in the Nestos River. However, the reliability of the regression equations would have been higher if more measured data were available.

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