System Stability | ScienceGate

Постановка задачи. Рассматривается теплообменный процесс, протекающий в модифицированном гофрированном межпластинном канале интенсифицированного пластинчатого теплообменного аппарата с повышенной турбулизацией теплоносителя. Необходимо разработать компьютерную модель движения теплоносителя в диапазоне скоростей 0,1-1,5 м/с и определить коэффициент турбулизации пластинчатого теплообменника. Результаты. Приведены результаты компьютерного моделирования движения теплоносителя в межпластинном гофрированном канале оригинального пластинчатого теплообменного аппарата с помощью программного комплекса Аnsys . Определены критерии устойчивости системы. Выполнено 3 D -моделирование канала, образуемого гофрированными пластинами. При исследовании процесса турбулизации были рассмотрены несколько скоростных режимов движения теплоносителя. Определен коэффициент турбулизации Tu, %. Выводы. В результате компьютерного моделирования установлено увеличение коэффициента теплопередачи К, Вт/(м ℃ ) за счет повышенной турбулизации потока, что приводит к снижению металлоемкости и уменьшению стоимости теплообменного оборудования. Statement of the problem. The heat exchange process occurring in a modified corrugated interplate channel of an intensified plate heat exchanger with an increased turbulence of the heat carrier is discussed. A computer model of the coolant movement in the speed range of 0.1-1.5 m/s is developed and the turbulence coefficient of the plate heat exchanger is determined. Results. The article presents the results of computer modeling of the coolant movement in the interplate corrugated channel of the original plate heat exchanger using the Ansys software package. The criteria of system stability are defined. 3D modeling of the channel formed by corrugated plates is performed. In the study of the process of turbulence several high-speed modes of movement of the coolant were considered. The turbulence coefficient Tu, % is determined. Conclusions. As a result of computer simulation, an increase in the heat transfer coefficient K, W/(m ℃) was found due to an increased turbulization of the flow, which leads to a decrease in metal consumption and a decrease in the cost of heat exchange equipment.

Download Full-text

Russian Banking System: Stability Factors in the Wake of 2008-2009 Crisis

SSRN Electronic Journal ◽

10.2139/ssrn.2186117 ◽

2012 ◽

Author(s):

Andrey Zubarev

Keyword(s):

Banking System ◽

System Stability

Download Full-text

Stock Market Prices and Financial System Stability

SSRN Electronic Journal ◽

10.2139/ssrn.3443372 ◽

2019 ◽

Author(s):

Zaäfri A. Husodo ◽

Muhammad Budi Prasetyo ◽

Rizky Luxianto ◽

Theresia Silitonga ◽

Januar Hafidz ◽

...

Keyword(s):

Stock Market ◽

Financial System ◽

System Stability ◽

Market Prices

Download Full-text

A FO-PID Controlled Automatic Generation Control of Multi Area Power Systems Tuned by Harmony Search

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096511666180719105754 ◽

2020 ◽

Vol 13 (1) ◽

pp. 101-109

Author(s):

Aurobindo Behera ◽

Tapas K. Panigrahi ◽

Arun K. Sahoo

Keyword(s):

Power Systems ◽

Harmony Search ◽

Automatic Generation ◽

System Stability ◽

Automatic Generation Control ◽

Similar System ◽

Thermal Plant ◽

Clear Idea ◽

Generation Control ◽

Fractional Controller

Background: Power system stability demands minimum variation in frequency, so that loadgeneration balance is maintained throughout the operation period. An Automatic Generation Control (AGC) monitors the frequency and varies the generation to maintain the balance. A system with multiple energy sources and use of a fractional controller for efficient control of stability is presented in the paper. At the outset a 2-area thermal system with governor dead band, generation rate constraint and boiler dynamics have been applied. Methods: A variation of load is deliberated for the study of the considered system with Harmony Search (HS) algorithm, applied for providing optimization of controller parameters. Integral Square Time Square Error (ISTSE) is chosen as objective function for handling the process of tuning controller parameters. : A study of similar system with various lately available techniques such as TLBO, hFA-PS and BFOA applied to PID, IDD and PIDD being compared to HS tuned fractional controller is presented under step and dynamic load change. The effort extended to a single area system with reheat thermal plant, hydel plant and a unit of wind plant is tested with the fractional controller scheme. Results: The simulation results provide a clear idea of the superiority of the combination of HS algorithm and FO-PID controller, under dynamically changing load. The variation of load is taken from 1% to 5% of the connected load. Conclusion: Finally, system robustness is shown by modifying essential factors by ± 30%.

Download Full-text

Testing the Causal Mechanisms in Additional Cases

10.1093/oso/9780198807872.003.0008 ◽

2017 ◽

Author(s):

Paul D. Kenny

Keyword(s):

Twentieth Century ◽

Latin America ◽

Case Studies ◽

Democratic Party ◽

Party System ◽

Liberal Democratic Party ◽

System Stability ◽

Relative Autonomy ◽

Causal Mechanisms ◽

Liberal Democratic

Case studies of Indonesia and Japan illustrate that party-system stability in patronage democracies is deeply affected by the relative autonomy of political brokers. Over the course of a decade, a series of decentralizing reforms in Indonesia weakened patronage-based parties hold on power, with the 2014 election ultimately being a contest between two rival populists: Joko Widodo and Subianto Prabowo. Although Japan was a patronage democracy throughout the twentieth century, the ruling Liberal Democratic Party (LDP) remained robust to outsider appeals even in the context of economic and corruption crises. However, reforms in the 1990s weakened the hold of central factional leaders over individual members of the LDP and their patronage machines. This was instrumental to populist Junichiro Koizumi’s winning of the presidency of the LDP and ultimately the prime ministership of Japan. This chapter also reexamines canonical cases of populism in Latin America.

Download Full-text

Introduction

10.1093/oso/9780198826927.003.0001 ◽

2018 ◽

Author(s):

Ekrem Karakoç

Keyword(s):

Party System ◽

Median Voter ◽

System Stability ◽

New Democracies ◽

The Czech Republic ◽

Electoral Volatility ◽

Large N ◽

Multimethod Approach ◽

Median Voter Theory ◽

Nondemocratic Regimes

This chapter opens by providing empirical evidence that income inequality persists or increases in many new democracies after their transition. Then it gives a brief overview of studies that expect reduced inequality because of democratization and questions their three assumptions regarding median voters, party system stability, and the authoritarian legacy on citizen–party linkage. It offers a revision to the median voter theory, emphasizes high electoral volatility in new democracies, and reexamines the legacy of previous nondemocratic regimes on citizen–party linkage. Having offered its argument in a nutshell, it turns to research methodology and case selection. It offers the rationale behind employing a multimethod approach to test its arguments. It tests its argument through large-N analysis in new and longstanding democracies in Europe as well as two paired case studies: Poland and the Czech Republic in postcommunist Europe and Turkey and Spain in Southern Europe.

Download Full-text