IDENTIFICATION OF RIVER WATER EXCESSIVE POLLUTION SOURCES

2006 ◽  
Vol 05 (02) ◽  
pp. 397-417 ◽  
Author(s):  
K. J. KACHIASHVILI ◽  
D. I. MELIKDZHANIAN
Keyword(s):  
Mathematical Models ◽  
River Water ◽  
Cross Sections ◽  
Pollutant Transport ◽  
Pollution Sources ◽  
Program Package ◽  
Statistical Hypotheses ◽  
Identical Composition

The program package for identification of river water excessive pollution sources located between two controlled cross-sections of the river is described in this paper. The software has been developed by the authors on the basis of mathematical models of pollutant transport in the rivers and statistical hypotheses checking methods. The identification algorithms were elaborated with the supposition that the pollution sources discharge different compositions of pollutants or (at the identical composition) different proportions of pollutants into the rivers.

Using Arc GIS to explore the impact of environmental and ecological factors on water body

2021 ◽  
Vol 7 (6) ◽  
pp. 6247-6261
Author(s):  
Xiaoqing Liu ◽  
Juanfen Wang
Keyword(s):  
Water Quality ◽  
Numerical Model ◽  
Point Source ◽  
River Water ◽  
Ecological Factors ◽  
River Water Quality ◽  
Pollution Sources ◽  
Point Source Pollution ◽  
The Impact ◽  
Non Point Source Pollution

As water pollution is more and more serious, ArcGIS is proposed to explore the impact of environmental and ecological factors on water. Taking the river water quality as the research object, this paper simulates and analyzes the endogenous and non-point source pollution and water quality through indoor physical model experiment, hydrological and water quality numerical model and water quality numerical model, and analyzes the impact of different environmental changes on river water quality and pollution sources from micro and macro perspectives. The main contents include: experimental study on the influence mechanism of overlying water velocity, disturbance and water temperature on sediment endogenous release, construction and simulation of watershed non-point source pollution model, construction and simulation of watershed river water quality model, as well as the impact of environmental change on river water quality and quantitative analysis of river pollution sources.

Twin-rotor hover performance examination using overlap tests

2017 ◽  
Vol 89 (1) ◽  
pp. 155-163
Author(s):  
Farid Shahmiri
Keyword(s):  
Mathematical Models ◽  
Cross Sections ◽  
Test Model ◽  
Test Plan ◽  
Optimal Test ◽  
Content Type ◽  
Hover Performance ◽  
Power Loading ◽  
Overlap Ratio ◽  
Twin Rotor

Purpose The aim of this paper was to experimentally examine twin-rotor hover performance for different rotor overlap ratios at practical rotor loading. Design/methodology/approach The methodology was formed based on data measurements for a designed twin-rotor test model and development of hover performance mathematical models. Thus, measurements were made using a central composite test plan, and then mathematical models for thrust power required power loading (PL) and figure of merit (FM) as functions of collective pitch tip speed; rotor overlap ratio was obtained. In the present paper, the test model consisted of two three-bladed rotors with a diameter of 220 mm and a blade aspect ratio of 16.05. The blades were of a rectangular planform with NACA 0012 cross sections and had no twist or taper. The model was built such that the rear rotor was fixed on the fuselage, and the front rotor could move longitudinally for tests up to about 40 per cent overlap ratio in hover. Findings The best hover aerodynamic efficiency (maximum PL of 14.6 kg/kW) was achieved for non-overlapped rotors at a low value of disc loading (DL) and also at FM of 0.6 at that DL. This result was in agreement with blade element momentum theory predictions. Practical implications Results for the twin-rotor test model can be generalized for actual tandem helicopters through the Reynolds number transformation technique and also some modifications. Originality/value Design and construction of the twin-rotor test model and experimental measurements of hover performance based on an optimal test plan were performed for the first time.

scholarly journals Influence of structural reinforcements on the twist-to-bend ratio of plant axes: a case study on Carex pendula

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Steve Wolff-Vorbeck ◽  
Olga Speck ◽  
Thomas Speck ◽  
Patrick W. Dondl
Keyword(s):  
Mathematical Models ◽  
Cross Sections ◽  
Torsional Rigidity ◽  
Biological Evolution ◽  
Strong Increase ◽  
Herbaceous Plant ◽  
Fibre Reinforcement ◽  
Vascular Bundles ◽  
Flower Stalk

AbstractDuring biological evolution, plants have developed a wide variety of body plans and concepts that enable them to adapt to changing environmental conditions. The trade-off between flexural and torsional rigidity is an important example of sometimes conflicting mechanical requirements, the adaptation to which can be quantified by the dimensionless twist-to-bend ratio. Our study considers the triangular flower stalk of Carex pendula, which shows the highest twist-to-bend ratios ever measured for herbaceous plant axes. For an in-depth understanding of this peak value, we have developed geometric models reflecting the 2D setting of triangular cross-sections comprised of a parenchymatous matrix with vascular bundles surrounded by an epidermis. We analysed the mathematical models (using finite elements) to measure the effect of either reinforcements of the epidermal tissue or fibre reinforcements such as collenchyma and sclerenchyma on the twist-to-bend ratio. The change from an epidermis to a covering tissue of corky periderm increases both the flexural and the torsional rigidity and decreases the twist-to-bend ratio. Furthermore, additional individual fibre reinforcement strands located in the periphery of the cross-section and embedded in a parenchymatous ground tissue lead to a strong increase of the flexural and a weaker increase of the torsional rigidity and thus resulted in a marked increase of the twist-to-bend ratio. Within the developed model, a reinforcement by 49 sclerenchyma fibre strands or 24 collenchyma fibre strands is optimal in order to achieve high twist-to-bend ratios. Dependent on the mechanical quality of the fibres, the twist-to-bend ratio of collenchyma-reinforced axes is noticeably smaller, with collenchyma having an elastic modulus that is approximately 20 times smaller than that of sclerenchyma. Based on our mathematical models, we can thus draw conclusions regarding the influence of mechanical requirements on the development of plant axis geometry, in particular the placement of reinforcements.

Seasonality Of The Basic Physical And Chemical Characteristics Of Water Flowing Through The Cascades Of Small Reservoirs In Urban And Suburban Areas

2013 ◽  
Vol 13 (2) ◽  
pp. 63-71 ◽  
Author(s):  
Adam Bartnik ◽  
Piotr Moniewski ◽  
Przemysław Tomalski
Keyword(s):  
River Water ◽  
Cross Sections ◽  
Seasonal Fluctuations ◽  
Water Conductivity ◽  
Water Turbidity ◽  
Suburban Areas ◽  
Before And After ◽  
Group Water ◽  
Using Data ◽  
Physical And Chemical

Abstract The paper showed the changes of characteristics of river water flowing through the cascades of reservoirs. One of the cascades is located in a highly urbanized area of Lodz. The second is in a suburban area on the northern outskirts of Lodz agglomeration. However, it still remains under the influence of storm water discharged from the highway. Every 2 weeks, in 4 monitoring points (on the input and on the output of each cascade), the measurements of basic physical and chemical water parameters were made (using data registered in cross-sections obtained between 2006 and 2012). The analysed characteristics can be divided into three groups: 1. No changes in the seasonal fluctuations of analysed characteristics before and after the cascade of reservoirs and no differences between urban and suburban areas in the influence of the cascades on river water; 2. Significant changes in the seasonal fluctuations of analysed characteristics before and after the cascade of reservoirs and no differences between urban and suburban areas in the influence of the cascades on river water; 3. Significant changes in the seasonal fluctuations of analysed characteristics before and after the cascade of reservoirs and also significant differences between urban and suburban areas in the influence of the cascades on river water. The first group includes the temperature and pH of the water, the second group water conductivity and the third group water turbidity and dissolved oxygen in water.

An Estimation of Pollution Sources with Monitoring of River Water Quality

1977 ◽  
Vol 10 (7) ◽  
pp. 9-16
Author(s):  
Yuzura Matsuoka ◽  
Hisashi Sumitomo ◽  
Shigeshisa Iwai
Keyword(s):  
Water Quality ◽  
River Water ◽  
River Water Quality ◽  
Pollution Sources

Spatial and Temporal Variation of Water Quality of Typical Rivers in the River-Network Plain to the East of Tai Lake

2012 ◽  
Vol 518-523 ◽  
pp. 4253-4260 ◽  
Author(s):  
Rong Rong Wan ◽  
Xin Yao ◽  
Zhong Hua Yu ◽  
Ya Wen Dong
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Land Use ◽  
River Water ◽  
Cross Sections ◽  
Buffer Zone ◽  
River Network ◽  
Spatial And Temporal Variation ◽  
Flow Parameters ◽  
Tai Lake

Nine cross sections of three typical rivers in the river-network plain to the east of Tai Lake were selected to measure water quality and water flow parameters monthly from September 2007 to August 2008. The spatial and temporal features of water quality were analyzed and the water pollution loads at river sections were estimated using statistic analysis. Combining land use in the riparian buffer zone interpreted form Remote Sensing images, the relationship between river water pollution load and land use were analyzed. It was clear that river water in the study area was polluted so seriously that water quality was ranked Grade V or worse. Pollutant input process in most river sections prevailed river self-purifying process. River qualities varied seasonally as that pollutant were denser in spring and winter than that in summer and autumn. Residential land in the 100 m buffer zone and industrial land in the 500 m buffer zone had the greatest influence on water quality. Forested and grassed riparian land appeared important in mitigating water quality degradation.

scholarly journals A comprehensive one-dimensional numerical model for solute transport in rivers

2017 ◽  
Vol 21 (1) ◽  
pp. 99-116 ◽  
Author(s):  
Maryam Barati Moghaddam ◽  
Mehdi Mazaheri ◽  
Jamal MohammadVali Samani
Keyword(s):  
Cross Sections ◽  
Pollutant Transport ◽  
Study Data ◽  
Transient Storage ◽  
Third Order ◽  
Transport Models ◽  
Storage Model ◽  
Proposed Model ◽  
Main Effect ◽  
Transient Storage Zones

Abstract. One of the mechanisms that greatly affect the pollutant transport in rivers, especially in mountain streams, is the effect of transient storage zones. The main effect of these zones is to retain pollutants temporarily and then release them gradually. Transient storage zones indirectly influence all phenomena related to mass transport in rivers. This paper presents the TOASTS (third-order accuracy simulation of transient storage) model to simulate 1-D pollutant transport in rivers with irregular cross-sections under unsteady flow and transient storage zones. The proposed model was verified versus some analytical solutions and a 2-D hydrodynamic model. In addition, in order to demonstrate the model applicability, two hypothetical examples were designed and four sets of well-established frequently cited tracer study data were used. These cases cover different processes governing transport, cross-section types and flow regimes. The results of the TOASTS model, in comparison with two common contaminant transport models, shows better accuracy and numerical stability.

Testing Statistical Hypotheses about Rat Liver Foci

1989 ◽  
Vol 17 (4_part_1) ◽  
pp. 569-578 ◽  
Author(s):  
Richard W. Morris
Keyword(s):  
Cross Sections ◽  
Treatment Effect ◽  
Statistical Power ◽  
Unit Volume ◽  
Statistical Tests ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Hypothesis Tests ◽  
Statistical Hypotheses ◽  
Average Size

Tests of statistical hypotheses concerning treatment effect on the development of hepatocellular foci can be carried out directly on two-dimensional observations made on histologic sections or on estimates of the density and volume of foci in three dimensions. Inferences about differences in the density or size of foci from tests based on two-dimensional observations, however, can be misleading. This is because both the number of focus cross-sections observed in a tissue section and the percent area occupied by foci can be expressed in terms of the number of foci per unit volume of liver tissue and the mean focus size. As a consequence, a treatment difference may be caused by a difference in the density of foci, their average size, or both. Of more serious concern is the possibility that failure to detect a treatment effect may occur not only when there is no treatment effect but also when the density and size of foci differ between treatments in such a way that their product is unchanged. This can happen if the effect of treatment is to increase the number of foci and decrease their average size, or vice versa. A similar difficulty of interpretation is associated with hypothesis tests based on average focus cross-section area. Tests based on estimates of the number of foci per unit volume and mean focus volume allow direct inference about the quantities of interest, but these estimates are unstable because they have large variances. Empirical estimates of statistical power for the Wilcoxon rank sum test and the t-test from data on control rats suggest power may be limited in experiments with group sizes of ten and low observed numbers of focus cross-sections. If hypothesis tests based on estimates of the density and size of foci are to form the basis for a bioassay, then the power of statistical tests used to identify treatment effects should be investigated.

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