Continuous density transition

2020 ◽  
pp. 433-475
Keyword(s):  
Continuous Density

Development of hydrodynamic calculation method for selective water intake process in the reservoir with continuous density stratification along the entire depth

2018 ◽  
Author(s):  
Н.И. Музаев ◽  
К.С. Харебов ◽  
И.Д. Музаев
Keyword(s):  
Froude Number ◽  
Water Intake ◽  
Calculation Method ◽  
Density Stratification ◽  
Industrial Enterprises ◽  
Intake Process ◽  
Continuous Density ◽  
Power Stations ◽  
Hydrodynamic Calculation ◽  
Density Froude Number

Разработан гидродинамический метод расчета селективного водозаборного процесса в водоеме с непрерывной по всей глубине плотностной стратификацией. В качестве математической модели водозаборного процесса использована краевая задача линейной теории поверхностных гравитационных волн малой амплитуды в идеальной несжимаемой и неоднородной жидкости. Получена совокупность расчетных формул, которая позволяет решить задачу водоснабжения промышленных предприятий, в том числе тепловых и атомных электростанций, из водоемов с непрерывной плотностной стратификацией. Предлагаемый метод расчета позволяет определить скорость водозабора через окно и высоту водозаборного окна, которые обеспечивают надлежащее положение поверхности раздела, соответствующее заданной плотности (температуры) забираемой воды. The purpose of this work is to develop the hydrodynamic calculation method for selective water-intake process applied to the problem of water supply to industrial enterprises, including thermal and atomic power stations using the reservoirs with the continuous density stratification. In the method of solving the problem, the variation of density along the depth is approximated by an exponential function. The water is taken through a window arranged on the side of the water body. The boundary value problem for the linear theory of surface gravity waves of small amplitude in an ideal incompressible and inhomogeneous fluid is used as a mathematical model of the water intake process. As a result, a set of calculation formulas has been obtained that allows solving the problem of water supply to industrial enterprises, including thermal and nuclear power stations, from water bodies with a continuous density stratification along the depth. Computational experiments have been performed, the results of which are given in the form of graphs of the dependence of the thickness of the bottom layer of water sucking the window on the density Froude number and on the height of the water intake window. The following conclusions are made on the basis of the comparison of the developed hydrodynamic calculation method compared with the existing hydraulic method: 1. In the existing hydraulic method of calculation, only the law of the dependence of the thickness of the suction ground layer of water on the density Froude number is described, however the nature of its dependence on the height of the water intake window is not established. 2. In the hydrodynamic calculation method of selective water-intake process developed in the article, the law of the dependence of the sucking through the window water ground layer thickness both on the density Froude number and on the height of waterintake window is established. 3. In connection with the aforementioned deficiency of the hydraulic calculation method, in reservoirs characterized by a continuous density stratification in depth, calculations and design of selective water intake devices should be carried out according to the hydrodynamic method developed in the article.

scholarly journals Comparison of Tissue Loading Before and After the Creation of a Continuous Density Gradient in Porcine Islet Purification

Cell Medicine ◽  
2018 ◽  
Vol 10 ◽  
pp. 215517901878134 ◽  
Author(s):  
Chika Miyagi-Shiohira ◽  
Yoshiki Nakashima ◽  
Nana Ebi ◽  
Eri Hamada ◽  
Yoshihito Tamaki ◽  
...  
Keyword(s):  
Density Gradient ◽  
Stimulation Index ◽  
High Yield ◽  
Pancreatic Islet Transplantation ◽  
Post Transplantation ◽  
Porcine Pancreas ◽  
Purification Method ◽  
Continuous Density ◽  
Porcine Islet ◽  
The Impact

The purification step is one of the most important and difficult procedures in islet isolation for pancreatic islet transplantation. We previously reported that a purification method using large plastic bottles effectively achieved a high yield of islets from the porcine pancreas. In this study, we evaluated the impact of the timing of tissue loading on porcine islet purification using large plastic bottles. One method involved loading digested tissue after creating a continuous density gradient (tissue after gradient [TAG]). The other method involved loading digested tissue before creating a continuous density gradient (tissue before gradient [TBG]). There were no significant differences between TAG and TBG in terms of the islet yield, rates of viability and purity, score, and in the stimulation index after purification. Furthermore, there were no marked differences in the attainability or suitability of post-transplantation normoglycemia. Our study shows the equivalency of these two methods of islet purification.

Development of the Richtmyer-Meshkov instability on an interface with continuous density variation

1996 ◽  
Vol 31 (5) ◽  
pp. 672-677 ◽  
Author(s):  
S. G. Zaitsev ◽  
S. N. Titov ◽  
E. I. Chebotareva
Keyword(s):  
Density Variation ◽  
Continuous Density

scholarly journals Hybrid Continuous Density Hmm-Based Ensemble Neural Networks for Sensor Fault Detection and Classification in Wireless Sensor Network

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 745 ◽  
Author(s):  
Malathy Emperuman ◽  
Srimathi Chandrasekaran
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Wireless Sensor Networks ◽  
Fault Detection ◽  
Vector Quantization ◽  
Probabilistic Neural Network ◽  
Wireless Sensor ◽  
Detection Accuracy ◽  
Sensor Faults ◽  
Continuous Density

Sensor devices in wireless sensor networks are vulnerable to faults during their operation in unmonitored and hazardous environments. Though various methods have been proposed by researchers to detect sensor faults, only very few research studies have reported on capturing the dynamics of the inherent states in sensor data during fault occurrence. The continuous density hidden Markov model (CDHMM) is proposed in this research to determine the dynamics of the state transitions due to fault occurrence, while neural networks are utilized to classify the faults based on the state transition probability density generated by the CDHMM. Therefore, this paper focuses on the fault detection and classification using the hybridization of CDHMM and various neural networks (NNs), namely the learning vector quantization, probabilistic neural network, adaptive probabilistic neural network, and radial basis function. The hybrid models of each NN are used for the classification of sensor faults, namely bias, drift, random, and spike. The proposed methods are evaluated using four performance metrics which includes detection accuracy, false positive rate, F1-score, and the Matthews correlation coefficient. The simulation results show that the learning vector quantization NN classifier outperforms the detection accuracy rate when compared to the other classifiers. In addition, an ensemble NN framework based on the hybrid CDHMM classifier is built with majority voting scheme for decision making and classification. The results of the hybrid CDHMM ensemble classifiers clearly indicates the efficacy of the proposed scheme in capturing the dynamics of change of statesm which is the vital aspect in determining rapidly-evolving instant faults that occur in wireless sensor networks.

scholarly journals Boundary Isomorphism between Dirichlet Finite Solutions of Δu = Pu and Harmonic Functions

1973 ◽  
Vol 50 ◽  
pp. 7-20 ◽  
Author(s):  
Ivan J. Singer
Keyword(s):  
Differential Equation ◽  
Riemann Surface ◽  
Laplace Operator ◽  
Nontrivial Solution ◽  
Harmonic Functions ◽  
Green’S Functions ◽  
Hölder Continuous ◽  
Open Riemann Surface ◽  
Continuous Density ◽  
The Laplace Operator

Consider an open Riemann surface R and a density P(z)dxdy (z = x + iy), well defined on R. As was shown by Myrberg in [3], if P ≢ 0 is a nonnegative α-Hölder continuous density on R (0 < α ≤ 1) then there exists the Green’s functions of the differential equationp>on R, where Δ means the Laplace operator. As a consequence, there always exists a nontrivial solution on R.

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