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.

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.

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.

scholarly journals LARGE SCALE MODEL TESTS OF PLACED STONE BREAKWATERS

1976 ◽  
Vol 1 (15) ◽  
pp. 147 ◽  
Author(s):  
Charles K. Sollitt ◽  
Donald H. Debok
Keyword(s):  
Large Scale ◽  
Scale Model ◽  
Small Scale ◽  
Stable Model ◽  
Model Studies ◽  
Drag Forces ◽  
Port Facilities ◽  
Large Scale Model ◽  
Wave Heights ◽  
Water Depths

Large scale model studies reveal that Reynolds scaling can affect the apparent stability and wave modifying properties of layered breakwater structures. Results of a study for a breakwater configuration designed to protect offshore power and port facilities in water depths to 60 feet are presented and discussed. The armor layer of this structure is formed from quarried rock of irregular rectangular parallelepiped shape, individually placed perpendicular to 1:2 seaward slope and crest. The resulting armor layer is relatively smooth, densely packed and very stable. Model studies of similar configurations were studied at 1:10, 1:20 and 1:100 scale ratios. Stability, runup, rundown and reflection were measured for a variety of water depths, wave heights and periods. Analysis of the large scale test results establish that the placed stone armor is approximately as stable as dolos armor units. Runup, rundown and reflection respond similar to rough, impermeable slopes. Comparison of large and small scale results demonstrate that relative increases in drag forces at lower Reynolds numbers decrease stability and runup in small scale models.

scholarly journals Non-Repeatability, Scale- and Model Effects in Laboratory Measurement of Impact Loads Induced by an Overtopped Bore on a Dike Mounted Wall

2019 ◽  
Author(s):  
Maximilian Streicher ◽  
Andreas Kortenhaus ◽  
Corrado Altomare ◽  
Steven Hughes ◽  
Krasimir Marinov ◽  
...  
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Vertical Wall ◽  
Scale Factor ◽  
Scale Model ◽  
Small Scale ◽  
Length Scale ◽  
Force Measurements ◽  
Impact Forces ◽  
Small Scale Model

Abstract Overtopping bore impact forces on a dike mounted vertical wall were measured in similar large-scale (Froude length scale factor 1-to-4.3) and small-scale (Froude length scale factor 1-to-25) models. The differences due to scale effects were studied, by comparing the up-scaled force measurements from both models in prototype. It was noted that if a minimum layer thickness, velocity of the overtopping flow and water depth at the dike toe were maintained in the small-scale model, the resulting differences in impact force due to scale effects are within the range of differences due to non-repeatability and model effects.

Towards a Small-Scale Model for Ubiquitous Learning

2014 ◽  
pp. 60-76
Author(s):  
Jorge Luis Victória Barbosa ◽  
Débora Nice Ferrari Barbosa
Keyword(s):  
Large Scale ◽  
Scale Model ◽  
Small Scale ◽  
Context Aware ◽  
Ubiquitous Learning ◽  
Learning Spaces ◽  
Context Aware Computing ◽  
Real Scenario ◽  
Initial Results ◽  
Small Scale Model

The ever-increasing use of mobile devices allied to the widespread adoption of wireless network technology has greatly stimulated mobile and ubiquitous computing research. The adoption of mobile technology enables improvement to several application areas, such as education. New pedagogical opportunities can be created through the use of location systems and context-aware computing technology to track each learner's location and customize his/her learning process. In this chapter, the authors discuss a ubiquitous learning model called LOCAL (Location and Context Aware Learning). LOCAL was created to explore those aforementioned pedagogical opportunities, leveraging location technology and context management in order to support ubiquitous learning and facilitate collaboration among learners. This model was conceived for small-scale learning spaces, but can be extended in order to be applied to a large-scale environment. Initial results were obtained in a real scenario, attesting the viability of the approach.

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>

New Efficient Sparse Space–Time Algorithms for Superparameterization on Mesoscales

2009 ◽  
Vol 137 (12) ◽  
pp. 4307-4324 ◽  
Author(s):  
Yulong Xing ◽  
Andrew J. Majda ◽  
Wojciech W. Grabowski
Keyword(s):  
Large Scale ◽  
Space Time ◽  
Horizontal Velocity ◽  
Specific Humidity ◽  
Scale Model ◽  
Small Scale ◽  
Squall Lines ◽  
Scale Models ◽  
New Algorithms ◽  
Small Scale Model

Abstract Superparameterization (SP) is a large-scale modeling system with explicit representation of small-scale and mesoscale processes provided by a cloud-resolving model (CRM) embedded in each column of a large-scale model. New efficient sparse space–time algorithms based on the original idea of SP are presented. The large-scale dynamics are unchanged, but the small-scale model is solved in a reduced spatially periodic domain to save the computation cost following a similar idea applied by one of the authors for aquaplanet simulations. In addition, the time interval of integration of the small-scale model is reduced systematically for the same purpose, which results in a different coupling mechanism between the small- and large-scale models. The new algorithms have been applied to a stringent two-dimensional test suite involving moist convection interacting with shear with regimes ranging from strong free and forced squall lines to dying scattered convection as the shear strength varies. The numerical results are compared with the CRM and original SP. It is shown here that for all of the regimes of propagation and dying scattered convection, the large-scale variables such as horizontal velocity and specific humidity are captured in a statistically accurate way (pattern correlations above 0.75) based on space–time reduction of the small-scale models by a factor of ⅓; thus, the new efficient algorithms for SP result in a gain of roughly a factor of 10 in efficiency while retaining a statistical accuracy on the large-scale variables. Even the models with ⅙ reduction in space–time with a gain of 36 in efficiency are able to distinguish between propagating squall lines and dying scattered convection with a pattern correlation above 0.6 for horizontal velocity and specific humidity. These encouraging results suggest the possibility of using these efficient new algorithms for limited-area mesoscale ensemble forecasting.

The Small-Scale Distortion Model Design Method for Ultimate Strength Test of Hull Girder

2014 ◽  
Author(s):  
Chenfeng Li ◽  
Huilong Ren ◽  
Donghao Xu ◽  
Zeng Ji
Keyword(s):  
Large Scale ◽  
Design Method ◽  
Scale Model ◽  
Small Scale ◽  
Model Design ◽  
Hull Girder ◽  
Distortion Model ◽  
Section Modulus ◽  
Large Scale Model ◽  
Ultimate Moment

The objective of this paper is to develop a design method of small-scale distortion model for ultimate bearing capacity test. The ultimate moment is an important index of ship girder strength. Experimental analyses are regarded as the most straightforward and effective methods to predict ultimate moment of hull girder, especially full-scale and/or large-scale model testing. However, large-scale model test not only requires high loading capacity of test device, but it also costs a lot of human and material resources. Based on the similarity theory and failure mechanism of hull girder under bending, a small-scale distortion model design method is presented in this paper. In which, the transverse section is divided into several parts, such as main deck, middle deck, bottom and so on. Then, two similar criterions are required to follow. There are section modulus of each part and critical stress of main stiffened plats. The similar section modulus ensures a similar stress distribution of transverse section between model and real structures under bending; the similar critical stress ensures the same failure modes of stiffened plates. Based on this method, a real vessel is taken as example to design its small-scale (1/25 scale) distortion model. The simulating results indicate that this model design method is precise and reliable.

Uncertainty analysis at large scales: limitations and subjectivity of current practices - a water quality case study

2007 ◽  
Vol 56 (6) ◽  
pp. 1-9 ◽  
Author(s):  
R.M. Bijlsma ◽  
P. Groenendijk ◽  
M.W. Blind ◽  
A.Y. Hoekstra
Keyword(s):  
Uncertainty Analysis ◽  
Large Scale ◽  
Evidence Base ◽  
Uncertainty Assessment ◽  
Scale Model ◽  
Small Scale ◽  
Model Studies ◽  
Large Scale Model ◽  
Current Practices

Uncertainty analysis for large-scale model studies is a challenging activity that requires a different approach to uncertainty analysis at a smaller scale. However, in river basin studies, the practice of uncertainty analysis at a large scale is mostly derived from practice at a small scale. The limitations and inherent subjectivity of some current practices and assumptions are identified, based on the results of a quantitative uncertainty analysis exploring the effects of input data and parameter uncertainty on surface water nutrient concentration. We show that: (i) although the results from small- scale sensitivity analysis are often applied at larger scales, this is not always valid; (ii) the current restriction of the uncertainty assessment to uncertainty types with a strong evidence base gives structurally conservative estimates; (iii) uncertainty due to bias is usually not assessed, but it may easily outweigh the effects of variability; (iv) the uncertainty bandwidth may increase for higher aggregation levels, although the opposite is the standard assumption.

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