Multi-Scale Numerical Model for Groundwater flow Simulation of a Karst Tunnel in Kunming,China

2020 ◽  
Author(s):  
Mo Xu ◽  
Jihong Qi ◽  
Yige Tang ◽  
Xiao Li ◽  
JIan Guo
Keyword(s):  
Groundwater Flow ◽  
Water Level ◽  
Large Scale ◽  
Early Stage ◽  
Water Discharge ◽  
Scale Model ◽  
Small Scale ◽  
Tunnel Construction ◽  
Multi Scale ◽  
Pipe Model

<p>Due to the inhomogeneity of the carbonate rocks and discreteness of the karst water, delineation of the groundwater flow within karst area remains a challenging task as yet. Based on KunCheng tunnel of a water diversion project in KunMing, multi-scale groundwater flow models were set upto simulate the groundwater flow. Large scale model was used to obtain the boundary conditions and hydrogeological parameters, which were then assigned to the small scale model.The small scale model was generalized as an equivalent continuous medium, and two karst pipelines are established  by module River. After then,  the multi-scale numerical modelswere used to simulate the  groundwater seepage field and predict the recovery of groundwater after tunnel construction. The main results and conclusions are as follows.</p><p>(1)Black karst pipeline and white karst pipeline systems share one recharge source but have two independent discharge systems. The recharge source is the exposed karst rock in the northeast part of study area. Obstructed by aluminum clay rock of P<sub>1</sub>d, groundwater discharge is divided into two parts during the runoff process.</p><p>(2)During the tunnel construction process, the water level at the exit of White karst pipeline reduced 9m in pipe model B<sub>1</sub> while reduced 10m in the solution fissure model B<sub>2</sub>, both two models suggest that the tunnel construction will cause the drainage of White karst pipeline exit. The water level at the exit of black karst pipeline reduced 1m in pipe model B<sub>1</sub> while reduced 4m in the solution fissure model B<sub>2</sub>.</p><p>(3)In model B<sub>1</sub>, total water discharge during tunnel construction is 69876m<sup>3</sup>/d, in model B<sub>2</sub> , the total water discharge is 95817 m<sup>3</sup>/d  and  is much larger than model B<sub>1</sub> due to the quick groundwater transporting and exchange in karst pipeline..</p><p>(4)After the tunnel construction, exits of two pipelines and observation well see the water level recovery because of the formation sealing . The recovery trend is relatively rapid in the early stage, and slow in the later stage. It takes 8.5 years and 10 years for the exits of black and white pipelines and observation wells to reach the original water level, respectively. During the recovery process, groundwater exchange form was changing from pipe supplying aquifer to aquifer supplying pipe, which made model B<sub>2</sub> recovered faster than model B<sub>1</sub> in early stage, and vice versa.</p><p>Using large scale model combining with secondary scale model, and the module River to generalize karst pipeline can reflect the flow dynamic characteristics of karst pipeline effectively.</p>

scholarly journals Study on Multi-Scale Coupled Ecological Dispatching Model Based on the Decomposition-Coordination Principle

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1443
Author(s):  
Zhou ◽  
Dong ◽  
Wang ◽  
Shi ◽  
Gao ◽  
...  
Keyword(s):  
Large Scale ◽  
Scale Model ◽  
Small Scale ◽  
Adaptive Genetic Algorithm ◽  
Hydrologic Alteration ◽  
Multi Scale ◽  
Large Scale Model ◽  
Calculation Results ◽  
Coordination Principle ◽  
Small Scale Model

Studies on environmental flow have developed into a flow management strategy that includes flow magnitude, duration, frequency, and timing from a flat line minimum flow requirement. Furthermore, it has been suggested that the degree of hydrologic alteration be employed as an evaluation method of river ecological health. However, few studies have used it as an objective function of the deterministic reservoir optimal dispatching model. In this work, a multi-scale coupled ecological dispatching model was built, based on the decomposition-coordination principle, and considers multi-scale features of ecological water demand. It is composed of both small-scale model and large-scale model components. The small-scale model uses a daily scale and is formulated to minimize the degree of hydrologic alteration. The large-scale model uses a monthly scale and is formulated to minimize the uneven distribution of water resources. In order to avoid dimensionality, the decomposition coordination algorithm is utilized for the coordination among subsystems; and the adaptive genetic algorithm (AGA) is utilized for the solution of subsystems. The entire model—which is in effect a large, complex system—was divided into several subsystems by time and space. The subsystems, which include large-scale and small-scale subsystems, were correlated by coordinating variables. The lower reaches of the Yellow River were selected as the study area. The calculation results show that the degree of hydrologic alteration of small-scale ecological flow regimes and the daily stream flow can be obtained by the model. Furthermore, the model demonstrates the impact of considering the degree of hydrologic alteration on the reliability of water supply. Thus, we conclude that the operation rules extracted from the calculation results of the model contain more serviceable information than that provided by other models thus far. However, model optimization results were compared with results from the POF approach and current scheduling. The comparison shows that further reduction in hydrologic alteration is possible and there are still inherent limitations within the model that need to be resolved.

RANCANG BANGUN PERANGKAT EKSPERIMENTASI PROSES PIROLISIS BIOMASA GELOMBANG MIKRO

2013 ◽  
Vol 14 (2) ◽  
Author(s):  
Noor Fachrizal
Keyword(s):  
Large Scale ◽  
Continuous Model ◽  
Biomass Energy ◽  
Scale Model ◽  
Small Scale ◽  
Laboratory Apparatus ◽  
Liquid Form ◽  
Large Scale Model ◽  
Bio Oil ◽  
Pyrolysis Of Biomass

Biomass such as agriculture waste and urban waste are enormous potency as energy resources instead of enviromental problem. organic waste can be converted into energy in the form of liquid fuel, solid, and syngas by using of pyrolysis technique. Pyrolysis process can yield higher liquid form when the process can be drifted into fast and flash response. It can be solved by using microwave heating method. This research is started from developing an experimentation laboratory apparatus of microwave-assisted pyrolysis of biomass energy conversion system, and conducting preliminary experiments for gaining the proof that this method can be established for driving the process properly and safely. Modifying commercial oven into laboratory apparatus has been done, it works safely, and initial experiments have been carried out, process yields bio-oil and charcoal shortly, several parameters are achieved. Some further experiments are still needed for more detail parameters. Theresults may be used to design small-scale continuous model of productionsystem, which then can be developed into large-scale model that applicable for comercial use.

scholarly journals Multi-Scale Ionospheric Anomalies Monitoring and Spatio-Temporal Analysis during Intense Storm

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 215
Author(s):  
Na Cheng ◽  
Shuli Song ◽  
Wei Li
Keyword(s):  
Magnetic Storm ◽  
Large Scale ◽  
Temporal Dynamics ◽  
Ionospheric Disturbance ◽  
Ionospheric Scintillation ◽  
Small Scale ◽  
Electron Content ◽  
Total Electron ◽  
Multi Scale ◽  
Intense Storm

The ionosphere is a significant component of the geospace environment. Storm-induced ionospheric anomalies severely affect the performance of Global Navigation Satellite System (GNSS) Positioning, Navigation, and Timing (PNT) and human space activities, e.g., the Earth observation, deep space exploration, and space weather monitoring and prediction. In this study, we present and discuss the multi-scale ionospheric anomalies monitoring over China using the GNSS observations from the Crustal Movement Observation Network of China (CMONOC) during the 2015 St. Patrick’s Day storm. Total Electron Content (TEC), Ionospheric Electron Density (IED), and the ionospheric disturbance index are used to monitor the storm-induced ionospheric anomalies. This study finally reveals the occurrence of the large-scale ionospheric storms and small-scale ionospheric scintillation during the storm. The results show that this magnetic storm was accompanied by a positive phase and a negative phase ionospheric storm. At the beginning of the main phase of the magnetic storm, both TEC and IED were significantly enhanced. There was long-duration depletion in the topside ionospheric TEC during the recovery phase of the storm. This study also reveals the response and variations in regional ionosphere scintillation. The Rate of the TEC Index (ROTI) was exploited to investigate the ionospheric scintillation and compared with the temporal dynamics of vertical TEC. The analysis of the ROTI proved these storm-induced TEC depletions, which suppressed the occurrence of the ionospheric scintillation. To improve the spatial resolution for ionospheric anomalies monitoring, the regional Three-Dimensional (3D) ionospheric model is reconstructed by the Computerized Ionospheric Tomography (CIT) technique. The spatial-temporal dynamics of ionospheric anomalies during the severe geomagnetic storm was reflected in detail. The IED varied with latitude and altitude dramatically; the maximum IED decreased, and the area where IEDs were maximum moved southward.

Simultaneous Segmentation of Fetal Hearts and Lungs for Medical Ultrasound Images via an Efficient Multi-scale Model Integrated With Attention Mechanism

2021 ◽  
pp. 016173462110425
Author(s):  
Jianing Xi ◽  
Jiangang Chen ◽  
Zhao Wang ◽  
Dean Ta ◽  
Bing Lu ◽  
...  
Keyword(s):  
Congenital Anomaly ◽  
Large Scale ◽  
Automatic Segmentation ◽  
Receptive Fields ◽  
Semantic Segmentation ◽  
Attention Mechanism ◽  
Scale Model ◽  
Ultrasound Images ◽  
Multi Scale ◽  
Task Irrelevant

Large scale early scanning of fetuses via ultrasound imaging is widely used to alleviate the morbidity or mortality caused by congenital anomalies in fetal hearts and lungs. To reduce the intensive cost during manual recognition of organ regions, many automatic segmentation methods have been proposed. However, the existing methods still encounter multi-scale problem at a larger range of receptive fields of organs in images, resolution problem of segmentation mask, and interference problem of task-irrelevant features, obscuring the attainment of accurate segmentations. To achieve semantic segmentation with functions of (1) extracting multi-scale features from images, (2) compensating information of high resolution, and (3) eliminating the task-irrelevant features, we propose a multi-scale model with skip connection framework and attention mechanism integrated. The multi-scale feature extraction modules are incorporated with additive attention gate units for irrelevant feature elimination, through a U-Net framework with skip connections for information compensation. The performance of fetal heart and lung segmentation indicates the superiority of our method over the existing deep learning based approaches. Our method also shows competitive performance stability during the task of semantic segmentations, showing a promising contribution on ultrasound based prognosis of congenital anomaly in the early intervention, and alleviating the negative effects caused by congenital anomaly.

scholarly journals Variational data assimilation with superparameterization

2015 ◽  
Vol 2 (2) ◽  
pp. 513-536 ◽  
Author(s):  
I. Grooms ◽  
Y. Lee
Keyword(s):  
Data Assimilation ◽  
Large Scale ◽  
Climate Models ◽  
Low Cost ◽  
Ocean Model ◽  
Variational Data Assimilation ◽  
Scale Model ◽  
Small Scale ◽  
New Applications ◽  
Lorenz 96

Abstract. Superparameterization (SP) is a multiscale computational approach wherein a large scale atmosphere or ocean model is coupled to an array of simulations of small scale dynamics on periodic domains embedded into the computational grid of the large scale model. SP has been successfully developed in global atmosphere and climate models, and is a promising approach for new applications. The authors develop a 3D-Var variational data assimilation framework for use with SP; the relatively low cost and simplicity of 3D-Var in comparison with ensemble approaches makes it a natural fit for relatively expensive multiscale SP models. To demonstrate the assimilation framework in a simple model, the authors develop a new system of ordinary differential equations similar to the two-scale Lorenz-'96 model. The system has one set of variables denoted {Yi}, with large and small scale parts, and the SP approximation to the system is straightforward. With the new assimilation framework the SP model approximates the large scale dynamics of the true system accurately.

Modelling present and future Po river interactions with alluvial aquifers (Low Po River Plain, Italy)

2014 ◽  
Vol 5 (3) ◽  
pp. 457-471 ◽  
Author(s):  
M. Mastrocicco ◽  
N. Colombani ◽  
A. Gargini
Keyword(s):  
Groundwater Flow ◽  
Large Scale ◽  
Flow Model ◽  
Transient Flow ◽  
Scale Model ◽  
Groundwater Flow Model ◽  
Po River ◽  
Local Conditions ◽  
Aquifer System ◽  
Hydrological Conditions

A modelling study on a multi-layered confined/unconfined alluvial aquifer system was performed to quantify surface water/groundwater interactions. The calibrated groundwater flow model was used to forecast climate change impacts by implementing the results of a downscaled A1B model ensemble for the Po river valley. The modelled area is located in the north-western portion of the Ferrara Province (Northern Italy), along the eastern bank of the Po river. The modelling procedure started with a large scale steady state model followed by a transient flow model for the central portion of the domain, where a telescopic mesh refinement was applied. The calibration performance of both models was satisfactory, in both drought and flooding conditions. Subsequently, forecasted rainfall, evapotranspiration and Po river stage at 2050, were implemented in the calibrated large scale groundwater flow model and their uncertainties discussed. Three scenarios were run on the large scale model: the first simulating mean hydrological conditions and the other two simulating one standard deviation above and below the mean hydrological conditions. The forecasted variations in groundwater/Po river fluxes are relevant, with a general increase of groundwater levels due to local conditions, although there are large uncertainties in the predicted variables.

Metagenomic and Metatranscriptomic Responses of Chemical Dispersant Application during a Marine Dilbit Spill

2022 ◽  
Author(s):  
Yiqi Cao ◽  
Baiyu Zhang ◽  
Charles W. Greer ◽  
Kenneth Lee ◽  
Qinhong Cai ◽  
...  
Keyword(s):  
Microbial Community ◽  
Late Stage ◽  
Large Scale ◽  
Community Dynamics ◽  
Early Stage ◽  
Small Scale ◽  
Rrna Gene ◽  
Shotgun Metagenomics ◽  
Microcosm Studies ◽  
Over Time

The global increase in marine transportation of dilbit (diluted bitumen) can increase the risk of spills, and the application of chemical dispersants remains a common response practice in spill events. To reliably evaluate dispersant effects on dilbit biodegradation over time, we set large-scale (1500 mL) microcosms without nutrients addition using low dilbit concentration (30 ppm). Shotgun metagenomics and metatranscriptomics were deployed to investigate microbial community responses to naturally and chemically dispersed dilbit. We found that the large-scale microcosms could produce more reproducible community trajectories than small-scale (250 mL) ones based on the 16S rRNA gene amplicon sequencing. In the early-stage large-scale microcosms, multiple genera were involved into the biodegradation of dilbit, while dispersant addition enriched primarily Alteromonas and competed for the utilization of dilbit, causing depressed degradation of aromatics. The metatranscriptomic based Metagenome Assembled Genomes (MAG) further elucidated early-stage microbial antioxidation mechanism, which showed dispersant addition triggered the increased expression of the antioxidation process genes of Alteromonas species. Differently, in the late stage, the microbial communities showed high diversity and richness and similar compositions and metabolic functions regardless of dispersant addition, indicating the biotransformation of remaining compounds can occur within the post-oil communities. These findings can guide future microcosm studies and the application of chemical dispersants for responding to a marine dilbit spill. Importance In this study, we employed microcosms to study the effects of marine dilbit spill and dispersant application on microbial community dynamics over time. We evaluated the impacts of microcosm scale and found that increasing the scale is beneficial for reducing community stochasticity, especially in the late stage of biodegradation. We observed that dispersant application suppressed aromatics biodegradation in the early stage (6 days) whereas exerting insignificant effects in the late stage (50 days), from both substances removal and metagenomic/metatranscriptomic perspectives. We further found that Alteromonas species are vital for the early-stage chemically dispersed oil biodegradation, and clarified their degradation and antioxidation mechanisms. The findings would help to better understand microcosm studies and microbial roles for biodegrading dilbit and chemically dispersed dilbit, and suggest that dispersant evaluation in large-scale systems and even through field trails would be more realistic after marine oil spill response.

Fracture Strength Estimation of SiC Block for IS Process

2010 ◽  
Author(s):  
Hiroaki Takegami ◽  
Atsuhiko Terada ◽  
Kaoru Onuki ◽  
Ryutaro Hino
Keyword(s):  
Fracture Strength ◽  
Large Scale ◽  
Weibull Modulus ◽  
Reliability Assessment ◽  
Prediction Method ◽  
Scale Model ◽  
Small Scale ◽  
Energy Agency ◽  
Destructive Test ◽  
Small Scale Model

The Japan Atomic Energy Agency has been conducting R&D on thermochemical water-splitting Iodine-Sulfur (IS) process for hydrogen production to meet massive demand in the future hydrogen economy. A concept of sulfuric acid decomposer was developed featuring a heat exchanger block made of SiC. Recent activity has focused on the reliability assessment of SiC block. Although knowing the strength of SiC block is important for the reliability assessment, it is difficult to evaluate a large-scale ceramics structure without destructive test. In this study, a novel approach for strength estimation of SiC structure was proposed. Since accurate strength estimation of individual ceramics structure is difficult, a prediction method of minimum strength in the structure of the same design was proposed based on effective volume theory and optimized Weibull modulus. Optimum value of the Weibull modulus was determined for estimating the lowest strength. The strength estimation line was developed by using the determined modulus. The validity of the line was verified by destructive test of SiC block model, which is small-scale model of the SiC block. The fracture strength of small-scale model satisfied the predicted strength.

Large-Scale Assembly of Carbon Nanotubes

2004 ◽  
Author(s):  
T. El-Aguizy ◽  
Sang-Gook Kim
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Large Scale ◽  
Small Scale ◽  
Manufacturing Processes ◽  
Micro Scale ◽  
Multi Scale ◽  
Novel Method ◽  
Functionalization Of Carbon Nanotubes

The scale decomposition of a multi-scale system into small-scale order domains will reduce the complexity of the system and will subsequently ensure a success in nanomanufacturing. A novel method of assembling individual carbon nanotube has been developed based on the concept of scale decomposition. Current technologies for organized growth of carbon nanotubes are limited to very small-scale order. The nanopelleting concept is to overcome this limitation by embedding carbon nanotubes into micro-scale pellets that enable large-scale assembly as required. Manufacturing processes have been developed to produce nanopellets, which are then transplanted to locations where the functionalization of carbon nanotubes are required.

The Effects of Scaling and Model Complexity in Simulating the Transport of Inorganic Micropollutants in a Lowland River Reach

2006 ◽  
Vol 41 (1) ◽  
pp. 24-36 ◽  
Author(s):  
Karl-Erich Lindenschmidt ◽  
René Wodrich ◽  
Cornelia Hesse
Keyword(s):  
Large Scale ◽  
Transport Model ◽  
Transport Processes ◽  
Model Complexity ◽  
Scale Model ◽  
Small Scale ◽  
Quality Model ◽  
Large Scale Model ◽  
Iron And Zinc ◽  
Physical And Chemical

Abstract A hypothesis stating that more complex descriptions of processes in models simulate reality better (less error) but with more unreliable predictability (more sensitivity) is tested using a river water quality model. This hypothesis was extended stating that applying the model on a domain of smaller scale requires greater complexity to capture the same accuracy as in large-scale model applications which, however, leads to increased model sensitivity. The sediment and pollutant transport model TOXI, a module in the WASP5 package, was applied to two case studies of different scale: a 90-km course of the 5th order (sensu Strahler 1952) lower Saale river, Germany (large scale), and the lock-and-weir system at Calbe (small scale) situated on the same river course. A sensitivity analysis of several parameters relating to the physical and chemical transport processes of suspended solids, chloride, arsenic, iron and zinc shows that the coefficient, which partitions the total heavy metal mass into its dissolved and sorbed fraction, is a very sensitive parameter. Hence, the complexity of the sorptive process was varied to test the hypotheses.

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