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1.
Sci Total Environ ; 792: 148215, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465034

RESUMO

Tidal flats are biogeomorphic landscapes, shaped by physical forces and interaction with benthic biota. We used a metabolic approach to assess the overarching effect of bioturbators on tidal landscapes. The benthic bivalve common cockle (Cerastoderma edule) was used as model organism. The effect of C. edule on sediment resuspension was approximated as a function of the overall population metabolic rate per unit of area. We combined i) laboratory observations on how C. edule affect sediment resuspension along gradients of bioturbation activity, sediment cohesiveness and hydrodynamic force with ii) spatial data on the natural distribution of intertidal C. edule populations. This allowed us to build an integrated model of the C. edule effect on sediment resuspension along the tidal gradient. Owing to the temperature dependence of metabolic rate, the model also accounted for seasonal variation in bioturbators activity. Laboratory experiments indicated that sediment resuspension is positively related to the metabolic rate of the C. edule population especially in cohesive sediments. Based on this observation, we predicted a clear spatial and seasonal pattern in the relative importance of C. edule contribution to sediment resuspension along a tidal transect. At lower elevations, our model indicates that hydrodynamics overrules biotic effects; at higher elevations, inter-tidal hydrodynamics should be too low to suspend bioturbated sediments. The influence of C. edule on sediment resuspension is expected to be maximal at the intermediate elevation of a mudflat, owing to the combination of moderate hydrodynamic stress and high bioturbator activity. Also, bio-mediated sediment resuspension is predicted to be particularly high in the warm season. Research into metabolic dependency of bio-mediated sediment resuspension may help to place phenomenological observations in the broader framework of metabolic theories in ecology and to formulate general expectations on the coastal ecosystem functioning.


Assuntos
Bivalves , Cardiidae , Animais , Ecossistema , Sedimentos Geológicos , Hidrodinâmica
2.
Chaos ; 31(8): 083122, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34470224

RESUMO

Skin cancer is one of the most frequent cancers worldwide. Recently, it has been shown that the tumor proliferation rate in skin and its dynamics can be changed by an osmotic pressure. However, these findings are rather unstructured. A weak pressure can slow down the tumor growth, while a very high pressure can, on the contrary, lead to accelerated growth and metastases. The magnitude and spatial distribution of osmotic pressures in tumors at present cannot be measured experimentally. Therefore, it is of particular interest to find appropriate models that would simulate the effects of additional osmotic pressures in skin and assess the features of its implementation. In this paper, we suggest an improved model based on the principles of the conventional hydrodynamic model for macrophase separations, which allows one to include not only the properties of healthy and cancer cells but also the microenvironment. We study and analyze the proliferation of cancer cells in 3D models of the epidermal layer of skin under an osmotic pressure. There are two suggested 3D models that are based on the same principles: (1) cellular cubic lattice and (2) cell spheroid. This allows expanding the application of the model depending on a given task. Here, we are focused on the study of melanoma at an early stage when there are not many cancer cells. Additional compressive and expansive pressures are added to the central part of the system. Both systems demonstrate similar results in slowing down the rate of tumor growth with a small pressure.


Assuntos
Neoplasias , Humanos , Hidrodinâmica , Microambiente Tumoral
3.
Adv Exp Med Biol ; 1334: 205-222, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34476751

RESUMO

Computational fluid dynamics (CFD) is a tool that has been used by engineers for over 50 years to analyse heat transfer and fluid flow phenomena. In recent years, there have been rapid developments in biomedical and health research applications of CFD. It has been used to evaluate drug delivery systems, analyse physiological flows (e.g. laryngeal jet flow), facilitate surgical planning (e.g. management of intracranial aneurysms), and develop medical devices (e.g. vascular stents and valve prostheses). Due to the complexity of these fluid flows, it demands an interdisciplinary approach consisting of engineers, computer scientists, and mathematicians to develop the computer programs and software used to solve the mathematical equations. Advances in technology and decreases in computational cost are allowing CFD to be more widely accessible and therefore used in more varied contexts. Cardiovascular medicine is the most common area of biomedical research in which CFD is currently being used, followed closely by upper and lower respiratory tract medicine. CFD is also being used in research investigating cerebrospinal fluid, synovial joints, and intracellular fluid. Although CFD can provide meaningful and aesthetically pleasing outputs, interpretation of the data can be challenging for those without a strong understanding of mathematical and engineering principles. Future development and evolution of computational medicine will therefore require close collaboration between experts in engineering, computer science, and biomedical research. This chapter aims to introduce computational fluid dynamics and present the reader with the basics of biological fluid properties, the CFD method, and its applications within biomedical research through published examples, in hope of bridging knowledge gaps in this rapidly emerging method of biomedical analysis.


Assuntos
Hidrodinâmica , Aneurisma Intracraniano , Simulação por Computador , Humanos , Software , Stents
4.
Soft Matter ; 17(35): 8160-8174, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34525162

RESUMO

Despite being a fundamental tool in soft matter research and biosensing, quartz crystal microbalance (QCM) analyses of discrete macromolecules in liquids so far lack a firm theoretical basis. Quite often, acoustic signals of discrete particles are qualitatively interpreted using ad hoc frameworks based on effective electrical circuits, effective springs and trapped-solvent models with many fitting parameters. Nevertheless, due to its extreme sensitivity, the QCM technique pledges to become an accurate predictive tool. Using unsteady low Reynolds hydrodynamics we derive analytical expressions for the acoustic impedance of adsorbed discrete spheres. The present approach is successfully validated against 3D simulations and a plethora of experimental results covering more than a decade of research on proteins, viruses, liposomes, and massive nanoparticles, with sizes ranging from a few to hundreds of nanometers. The agreement without fitting parameters indicates that the acoustic response is dominated by the hydrodynamic propagation of the particle surface stress over the resonator. Understanding this leading contribution is a prerequisite for deciphering the secondary contributions arising from the relevant specific molecular and physico-chemical forces.


Assuntos
Técnicas Biossensoriais , Técnicas de Microbalança de Cristal de Quartzo , Hidrodinâmica , Lipossomos , Proteínas , Quartzo
5.
Proc Biol Sci ; 288(1956): 20211260, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34375552

RESUMO

The occurrence and proliferation of reef-forming corals is of vast importance in terms of the biodiversity they support and the ecosystem services they provide. The complex three-dimensional structures engineered by corals are comprised of both live and dead coral, and the function, growth and stability of these systems will depend on the ratio of both. To model how the ratio of live : dead coral may change, the 'Goldilocks Principle' can be used, where organisms will only flourish if conditions are 'just right'. With data from particle imaging velocimetry and numerical smooth particle hydrodynamic modelling with two simple rules, we demonstrate how this principle can be applied to a model reef system, and how corals are effectively optimizing their own local flow requirements through habitat engineering. Building on advances here, these approaches can be used in conjunction with numerical modelling to investigate the growth and mortality of biodiversity supporting framework in present-day and future coral reef structures.


Assuntos
Antozoários , Animais , Biodiversidade , Recifes de Corais , Ecossistema , Hidrodinâmica
6.
No Shinkei Geka ; 49(4): 888-897, 2021 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-34376621

RESUMO

Since intracranial aneurysm(IA)is a disease that follows an extremely unpredictable course, from initiation to rupture, experimental models have greatly contributed to a better understanding of IA pathophysiology. This article aims to review the history of IA models through the pivotal theme of the ideal IA model. In addition, this article introduces updated findings from the application of these experimental models. Though the first IA model, known as a venous pouch model, was reported in 1954, it mimicked only the shape of the IA, without reproducing its pathological structure or blood-flow characteristics. Currently, two models are generally applied: the "Hashimoto model," produced by unilateral common carotid artery(CCA)ligation followed by systemic hypertension and weakening of the vascular wall, and the "elastase injection model," induced by intraventricular elastase injection and also followed by systemic hypertension. In addition, other models, including a rabbit basilar top IA, developed after bilateral CCA ligation, and an artificial bifurcation model, generated by an anastomosis between the CCAs, have been found to be valuable for computational fluid dynamics analysis. Through this advancement, the IA model has gradually elucidated the pathophysiology of IA as a flow-induced inflammatory disease. Nowadays, vascular inflammation is suggested to be regulated by bacterial flora. Further development of IA models and a better understanding of IA pathophysiology are expected in the future.


Assuntos
Aneurisma Intracraniano , Animais , Artéria Carótida Primitiva , Modelos Animais de Doenças , Hemodinâmica , Humanos , Hidrodinâmica , Modelos Teóricos , Coelhos
7.
Water Res ; 203: 117504, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34388501

RESUMO

An integrated computational fluid dynamics (CFD)-kinetic model framework was developed to numerically describe the hydrodynamic and kinetic phenomena in a liquid-solid two phases Fluidized-bed reactor Fenton/granular activated carbon (FBR-Fenton/GAC) system. The model obtained excellent accuracy for predicting chemical oxygen demand (COD) removal in reverse osmosis concentrate (ROC) treatment under different operation conditions. Hydrodynamic evaluation demonstrated that under the quasi-steady state, the GAC particles were uniformly circulated in the bed region with two pairs of counter-rotating recirculation cells, and a clear interface layer formed between the solid and the liquid phases. Superficial liquid velocity highly affected the fluidized bed expansion and solid volume fraction, while its impact on the overall COD removal efficiency was negligible. Chemical evaluation revealed that GAC/H2O2 catalytic reaction enhanced the •OH production in FBR-Fenton/GAC process by 2.7 folds as compared to homogenous Fenton process. Fenton reaction mainly occurred in the upper liquid region and its kinetics for •OH generation significantly diminished by 75% within the first 10 min. GAC/H2O2 reaction took place in the fluidized bed region for continuous •OH generation with a relatively stable rate from 1.21 × 10-6 to 0.60 × 10-6 M/s. Along the ROC treatment with FBR-Fenton/GAC process, the simulated COD degradation rate decreased along the reaction time with 2.05 × 10-6 M/s and 2.93 × 10-7 M/s at 2 min and 60 min, respectively. Faster COD removal was attained in the fluidized bed region due to combining effects of •OH oxidation and GAC adsorption. The overall predicted COD concentration reduced from 122 to 35 mg/L, •OH oxidation and GAC adsorption contributed 59% and 41%, respectively, to the total COD removal.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Carvão Vegetal , Hidrodinâmica , Peróxido de Hidrogênio , Cinética , Eliminação de Resíduos Líquidos
8.
Water Res ; 203: 117528, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34399247

RESUMO

The addition of hydrogen to anaerobic digesters is an emerging technique for the sustainable upgrading of biogas to biomethane with renewable electricity. However, it is critically dependent on the effective gas-liquid transfer of hydrogen, which is a sparingly soluble gas. Very little is known about the impact of liquid and gas flow and bubble size on gas-liquid transfer during H2 injection in full-scale anaerobic digesters. A computational fluid dynamic model was developed using a two-fluid approach for non-Newtonian liquid in the open-source computational fluid dynamics (CFD) platform, OpenFOAM. The newly developed model was validated against published experimental data-sets of a gas-mixed, laboratory-scale anaerobic digester, with good agreement between the numerical and experimental velocity fields. The hydrodynamics of the full-scale in-situ biomethanation system using venturi ejectors for H2 injection was then simulated to investigate gas-liquid dynamics, including gas-liquid mass transfer, at different operational conditions. Gas-liquid mixing is mainly controlled by the gas-plumes interaction, which promotes turbulence at the interaction zone, resulting in increasing gas bubbles mixing with the liquid and the gas-liquid interfacial area. However, beyond the plume interaction zone, the digester had flow short-circuiting and inactive zones. It was found that, due to this short-circuiting behaviour, an increase in gas flow-rate may not be an effective option in reducing inactive zones, although it can increase the gas-liquid interfacial area. Comparative analysis of the impact of gas flow and bubble size indicated that gas flow had a linear effect on both kLa and gas holdup, but that bubble size had a non-linear impact, with higher kLa values achieved at bubble sizes less than 2 mm. Comparison against measured data in the same system indicated the predicted kLa values were at the same level as measured kLa, at a bubble size of 2 mm.


Assuntos
Biocombustíveis , Hidrodinâmica , Anaerobiose , Reatores Biológicos , Hidrogênio , Esterco , Metano
9.
Water Sci Technol ; 84(3): 632-643, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34388123

RESUMO

The water body inside the constructed wetland is affected by various factors, and the flow state is relatively complicated. There will always be a certain degree of low velocity area and rapid outflow phenomenon, which makes part of the space in the wetland unable to be effectively used. Based on Computational Fluid Dynamics (CFD) technology, this paper uses Fluent's porous media model and discrete phase model to establish a hydrodynamic model of up and down baffled subsurface flow constructed wetland system. The internal flow field of the wetland is simulated, and the hydraulic performance of different baffle settings and substrate laying methods in the wetland is systematically evaluated. The results show that when the number of baffles is the same, the hydraulic efficiency is higher when the first baffle is located on the lower part of the substrate. Compared with the position of the baffle, the increase in the number of baffles does not significantly improve the hydraulic efficiency of the constructed wetland. The substrate layer thickness ratio has a significant effect on the two parameters of the variance of the hydraulic residence time distribution (σ2) and the flow divergence (σ02). By increasing the thickness of the middle substrate, the low flow rate phenomenon caused by the small porosity substrate area of the upper layer and the rapid outflow phenomenon of the lower substrate can be improved to a certain extent, the utilization efficiency of the middle substrate layer is improved, and the hydraulic performance is increased. The research results are of great significance for improving the utilization of wetland space and ensuring its efficient decontamination and purification function.


Assuntos
Purificação da Água , Áreas Alagadas , Simulação por Computador , Hidrodinâmica , Eliminação de Resíduos Líquidos
10.
Rev Sci Instrum ; 92(7): 074101, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34340456

RESUMO

A fluid mechanics model of inhaled air gases, nitrogen (N2) and oxygen (O2) gases, and exhaled gas components (CO2 and water vapor particles) through a facial mask (membrane) to shield the COVID-19 virus is established. The model was developed based on several gas flux contributions that normally take place through membranes. Semiempirical solutions of the mathematical model were predicted for the N95 facial mask accounting on several parameters, such as a range of porosity size (i.e., 1-30 nm), void fraction (i.e., 10-3%-0.3%), and thickness of the membrane (i.e., 10-40 µm) in comparison to the size of the COVID-19 virus. A unitless number (Nr) was introduced for the first time to describe semiempirical solutions of O2, N2, and CO2 gases through the porous membrane. An optimum Nr of expressing the flow of the inhaled air gases, O2 and N2, through the porous membrane was determined (NO2 = NN2 = -4.4) when an N95 facial mask of specifications of a = 20 nm, l = 30 µm, and ε = 30% was used as a personal protection equipment (PPE). The concept of the optimum number Nr can be standardized not only for testing commercially available facial masks as PPEs but also for designing new masks for protecting humans from the COVID-19 virus.


Assuntos
COVID-19/prevenção & controle , Máscaras , SARS-CoV-2 , Fenômenos Biomecânicos , Dióxido de Carbono , Desenho de Equipamento , Expiração , Gases , Humanos , Hidrodinâmica , Inalação , Conceitos Matemáticos , Membranas Artificiais , Modelos Teóricos , Respiradores N95 , Nitrogênio , Oxigênio , Equipamento de Proteção Individual , Porosidade , Vapor
11.
Nat Commun ; 12(1): 4682, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34344886

RESUMO

A key impediment to studying water-related mechanisms in plants is the inability to non-invasively image water fluxes in cells at high temporal and spatial resolution. Here, we report that Raman microspectroscopy, complemented by hydrodynamic modelling, can achieve this goal - monitoring hydrodynamics within living root tissues at cell- and sub-second-scale resolutions. Raman imaging of water-transporting xylem vessels in Arabidopsis thaliana mutant roots reveals faster xylem water transport in endodermal diffusion barrier mutants. Furthermore, transverse line scans across the root suggest water transported via the root xylem does not re-enter outer root tissues nor the surrounding soil when en-route to shoot tissues if endodermal diffusion barriers are intact, thereby separating 'two water worlds'.


Assuntos
Raízes de Plantas/metabolismo , Água/metabolismo , Arabidopsis/anatomia & histologia , Arabidopsis/citologia , Arabidopsis/genética , Arabidopsis/metabolismo , Transporte Biológico , Hidrodinâmica , Modelos Biológicos , Mutação , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/citologia , Raízes de Plantas/genética , Brotos de Planta/metabolismo , Estômatos de Plantas/metabolismo , Análise Espectral Raman , Xilema/metabolismo
12.
Artigo em Inglês | MEDLINE | ID: mdl-34360365

RESUMO

Knowledge of dam construction in floodplain systems and its hydrodynamic effects plays a critical role in managing various kinds of floodplains. This study uses 3D floodplain hydrodynamic modeling to explore the possible effects of a proposed hydraulic project in Poyang Lake (PLHP) on the hydrodynamics, exemplified by a large floodplain system. Simulations showed that the water levels across most lake regions presented more significant changes than in the floodplain areas during the study period. The increased water levels upstream from the PLHP (~1.0 m) were distinctly higher than that downstream (~0.1 m). The PLHP may decrease the magnitude of the water velocities in the main channels of the lake, whereas velocities may experience mostly minor changes in the floodplains, depending upon the altered flow dynamics and transport. On average, the water temperature may exhibit mostly minor changes (~<1.0 °C) for both the horizontal and vertical scales within the flood-pulse-influenced lake system. Additionally, the model results indicated that the outflow process caused by the PLHP may be altered from the natural discharge into the Yangtze River to frequent backflow events during the storage period, demonstrating the non-negligible effect of the PLHP on the water supply for the downstream Yangtze River in the future.


Assuntos
Hidrodinâmica , Lagos , China , Hidrologia , Rios , Estações do Ano
13.
Sensors (Basel) ; 21(15)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34372232

RESUMO

The influence of wind on the maneuverability of sea-going vessels is a known factor limiting their maneuverability, especially in the case of very large vessels. Adverse weather conditions often limit the maneuverability of vessels or even make it impossible to enter the port. This results in longer delivery times for transported goods as well as measurable material losses for both carriers and their owners. This situation is often caused by a lack of information on differences in the prevailing weather conditions at the entrance to the port and at the seaport itself. There are simulation tools, such as the methods of computational fluid dynamics (CFD), which, after their appropriate adaptation and use in a virtual environment, have become important decision-making tools supporting the port administration when deciding about the movement of vessels. In this article, the authors present the results of research aimed at adapting one of the CFD methods for the needs of maritime navigation. The effects of the work were verified in a virtual environment and were successfully implemented in the port waters of Gdansk, Poland.


Assuntos
Hidrodinâmica , Vento , Simulação por Computador , Humanos , Polônia , Reprodutibilidade dos Testes
14.
Sensors (Basel) ; 21(13)2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34283129

RESUMO

The lateral line organ of fish has inspired engineers to develop flow sensor arrays-dubbed artificial lateral lines (ALLs)-capable of detecting near-field hydrodynamic events for obstacle avoidance and object detection. In this paper, we present a comprehensive review and comparison of ten localisation algorithms for ALLs. Differences in the studied domain, sensor sensitivity axes, and available data prevent a fair comparison between these algorithms from their original works. We compare them with our novel quadrature method (QM), which is based on a geometric property specific to 2D-sensitive ALLs. We show how the area in which each algorithm can accurately determine the position and orientation of a simulated dipole source is affected by (1) the amount of training and optimisation data, and (2) the sensitivity axes of the sensors. Overall, we find that each algorithm benefits from 2D-sensitive sensors, with alternating sensitivity axes as the second-best configuration. From the machine learning approaches, an MLP required an impractically large training set to approach the optimisation-based algorithms' performance. Regardless of the data set size, QM performs best with both a large area for accurate predictions and a small tail of large errors.


Assuntos
Sistema da Linha Lateral , Algoritmos , Animais , Peixes , Hidrodinâmica , Aprendizado de Máquina
15.
Comput Methods Programs Biomed ; 208: 106257, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34245951

RESUMO

OBJECTIVE: To evaluate the quantitative changes of respiratory functions for critically ill COVID-19 patients with mechanical ventilation, computational fluid dynamics (CFD) analysis was performed based on patient-specific three-dimensional airway geometry. METHODS: 37 cases of critically ill patients with COVID-19 admitted to the ICU of Huangshi Traditional Chinese Medicine Hospital from February 1st to March 20th, 2020 were retrospectively analyzed. 5 patients whose clinical data met the specific criteria were finally cataloged into death group (2 patients) and survival group (3 patients). The patient-specific three-dimensional airways were reconstructed from the central airways down to the 4th-5th bifurcation of the tracheobronchial tree. The volume changes of bronchi were calculated during the disease progression according to the comparison of two CT scans. Additionally, the changes of air flow resistance were analyzed using numerical simulation of CFD. RESULTS: Pearson correlation analysis demonstrated that there was negative correlation between the change of volume (ΔV) and the change of resistance (ΔR) for all COVID-19 patients (r=-0.7025). For total airway volume, an average decrease of -11.41±15.71% was observed in death group compared to an average increase of 1.86±10.80% in survival group (p=0.0232). For air flow through airways in lower lobe, the resistance increases for death group by 10.97±77.66% and decreases for survival group by -45.49±42.04% (p=0.0246). CONCLUSION: The variation of flow resistance in the airway could be used as a non-invasive functional evaluation for the prognosis and outcome of critically ill patients with COVID-19. The 'virtual' pulmonary function test by integrating follow-up CT scans with patient-derived CFD analysis could be a potentially powerful way in improving the efficiency of treatment for critically ill patients with COVID-19.


Assuntos
Resistência das Vias Respiratórias , COVID-19 , Estado Terminal , Humanos , Hidrodinâmica , Pulmão , Prognóstico , Estudos Retrospectivos , SARS-CoV-2
16.
Sci Total Environ ; 795: 148740, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34246148

RESUMO

A catchment model for river basins and a hydrodynamic model were combined in order to simulate the spreading of the turbidity plume produced by sediment discharges from the Guadalquivir River basin within the Gulf of Cádiz under different meteorological conditions. The current fields provided by the hydrodynamic model and a transport-diffusion scheme based on tracking virtual particles tracking released at the river mouth have enabled us to simulate turbidity plumes that show great similarity with the plumes observed in satellite images. The most relevant results of the study show that in the absence of winds, the plume tends to spread very slowly, gradually progressing northwards; this is because of the symmetry between the filling and draining flows at the mouth of the Guadalquivir and low intensity of the tidal currents beyond the mouth. In addition, the transport of the plume towards the Strait of Gibraltar requires wind conditions with a northerly, north-westerly or westerly component. Westwards transport, however, requires winds with an easterly, southerly, or south-easterly component. The periods of heaviest rainfall in the Guadalquivir River basin coincide with winds mainly from the west; therefore, the times of maximum discharge at the mouth of the river occur when there are wind conditions that favour the transport of the matter suspended in the plume, southwards along the coast, towards the Strait of Gibraltar and the Alboran Sea. Linking the watershed catchment and hydrodynamic models has proved its suitability to predict the evolution and reaching of the sediment plumes from the Guadalquivir River discharges and the experience encourages the use of that methodology to be applied in a future prediction system for the creation and evolution of those sediment plumes.


Assuntos
Hidrodinâmica , Rios , Gibraltar , Vento
17.
Sensors (Basel) ; 21(14)2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34300679

RESUMO

Scour around bridge piers remains the leading cause of bridge failure induced in flood. Floods and torrential rains erode riverbeds and damage cross-river structures, causing bridge collapse and a severe threat to property and life. Reductions in bridge-safety capacity need to be monitored during flood periods to protect the traveling public. In the present study, a scour monitoring system designed with vibration-based arrayed sensors consisting of a combination of Internet of Things (IoT) and artificial intelligence (AI) is developed and implemented to obtain real-time scour depth measurements. These vibration-based micro-electro-mechanical systems (MEMS) sensors are packaged in a waterproof stainless steel ball within a rebar cage to resist a harsh environment in floods. The floodwater-level changes around the bridge pier are performed using real-time CCTV images by the Mask R-CNN deep learning model. The scour-depth evolution is simulated using the hydrodynamic model with the selected local scour formulas and the sediment transport equation. The laboratory and field measurement results demonstrated the success of the early warning system for monitoring the real-time bridge scour-depth evolution.


Assuntos
Inteligência Artificial , Inundações , Hidrodinâmica , Rios , Vibração
18.
Water Sci Technol ; 84(2): 323-332, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34312340

RESUMO

Hydrodynamic simulation (CFD: computational fluid dynamics) is one of the major tools for planning the reconstruction and operation of the structures in wastewater treatment plants, and its routine use is commonplace because of the cost savings and efficiency gains that can be achieved. This paper provides examples of how CFD can contribute to substantial improvements in the overall efficiency of wastewater treatment plants.The case studies presented in the paper include rarely investigated issues, such as the operation of aerated grit chambers, performance of primary settling tanks, mixing performance in oxidation ditches and return sludge control. The results show that: (1) air intake rate can be strongly decreased in most of the grit chambers, (2) optimization of the inlet geometry design of primary settling tanks is crucial, especially at high loads caused by storm events, (3) mixer performance design based on current design guidelines is often of an unnecessarily high capacity, (4) sludge recirculation rate should be optimized by CFD investigations based on secondary settling tank performance.


Assuntos
Eliminação de Resíduos Líquidos , Purificação da Água , Hidrodinâmica , Modelos Teóricos , Esgotos
19.
Water Sci Technol ; 84(2): 333-348, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34312341

RESUMO

Appropriately used, computational fluid dynamics models are powerful tools to design and optimize primary settling tanks (PSTs). This paper uses a Fluent-based 3D model to identify the possible causes for underperformance of the circular PSTs at the Cali waste-water treatment plant, Colombia, and to propose design modifications to improve performance. A new configuration for the center well (CW) is proposed and evaluated. The influence of a rotational sludge scraper and of continuous sludge removal were considered in the numerical simulation. The new configuration included the modification of the current CW diameter and the location of a second baffle with the CW. The results suggest that the installation of the second baffle allows a more uniform flow distribution within the PST and consequently, the hydrodynamic problems associated with short-circuiting of the influent to the bottom of the tank are reduced. The second baffle suppresses the downward current, effectively dissipates the kinetic energy in the influent and forces the particles to move toward the bottom of the PST. In addition, the second CW baffle allows the formation in the inlet zone of a consistently more concentrated sludge blanket layer and thicker sludge, reducing the risk of solids leaving in the effluent of the PST.


Assuntos
Hidrodinâmica , Purificação da Água , Colômbia , Modelos Teóricos , Esgotos , Eliminação de Resíduos Líquidos
20.
Sensors (Basel) ; 21(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207336

RESUMO

The efficient and reliable monitoring of the flow of water in open channels provides useful information for preventing water slow-downs due to the deposition of materials within the bed of the channel, which might lead to critical floods. A reliable monitoring system can thus help to protect properties and, in the most critical cases, save lives. A sensing system capable of monitoring the flow conditions and the possible geo-environmental constraints within a channel can operate using still images or video imaging. The latter approach better supports the above two features, but the acquisition of still images can display a better accuracy. To increase the accuracy of the video imaging approach, we propose an improved particle tracking algorithm for flow hydrodynamics supported by a machine learning approach based on a convolutional neural network-evolutionary fuzzy integral (CNN-EFI), with a sub-comparison performed by multi-layer perceptron (MLP). Both algorithms have been applied to process the video signals captured from a CMOS camera, which monitors the water flow of a channel that collects rain water from an upstream area to discharge it into the sea. The channel plays a key role in avoiding upstream floods that might pose a serious threat to the neighboring infrastructures and population. This combined approach displays reliable results in the field of environmental and hydrodynamic safety.


Assuntos
Hidrodinâmica , Aprendizado de Máquina , Algoritmos , Eletrocardiografia , Redes Neurais de Computação
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