Green or gas in OPEC member countries: a linear and asymmetric investigation of energy–growth nexus

2020 ◽  
Author(s):  
Ebere Ume Kalu ◽  
Florence U. Nwafor ◽  
Augustine C. Arize ◽  
Leo‐Paul Dana ◽  
John Malindretos ◽  
...  
Keyword(s):  
2012 ◽  
Vol 22 (09) ◽  
pp. 1250207 ◽  
Author(s):  
DIEGO F. M. OLIVEIRA ◽  
MARKO ROBNIK

We study some dynamical properties of a classical time-dependent elliptical billiard. We consider periodically moving boundary and collisions between the particle and the boundary are assumed to be elastic. Our results confirm that although the static elliptical billiard is an integrable system, after introducing time-dependent perturbation on the boundary the unlimited energy growth is observed. The behavior of the average velocity is described using scaling arguments.


2010 ◽  
Vol 81 (5) ◽  
Author(s):  
Kushal Shah ◽  
Dmitry Turaev ◽  
Vered Rom-Kedar
Keyword(s):  

2010 ◽  
Vol 24 (13) ◽  
pp. 1449-1452
Author(s):  
ZHI-WEI GUO ◽  
DE-JUN SUN

The resonance phenomenon for nonmodal perturbation of Batchelor vortex is studied. For azimuthal wavenumber n = - 1, two resonant peaks appear and the left one is always dominant. For n = 1, the resonant character becomes very complicated. There is a resonant mode switch from right peak to left peak as swirl parameter q increases from 2 to infinity. The resonant wavenumber k is the largest when q approaches to infinity for n = - 1 while it is the smallest for n = 1. The maximum value of the optimal energy growth for n = 1 is at q approaches to infinity, whereas it decreases monotonically as q increases for n = - 1. The resonance for n = - 1 is the more important one.


2022 ◽  
Author(s):  
Nasiru Inuwa ◽  
Haruna Usman Modibbo ◽  
Sagir Adamu ◽  
Mohammed Bello Sani
Keyword(s):  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ismail Aliyu Danmaraya ◽  
Aminu Hassan Jakada ◽  
Suraya Mahmood ◽  
Bello Alhaji Ibrahim ◽  
Ahmad Umar Ali

Purpose The purpose of this paper is to look at the asymmetric effect of oil production on environmental degradation in OPEC member countries from 1970–2019. Design/methodology/approach The authors build a nonlinear panel ARDL–PMG model using the Shin et al. (2014) nonlinear autoregressive distributed lag (ARDL) approach in panel form to assess both the short- and long-run impact of positive and negative oil production movements on CO2 emissions. Findings The result demonstrates that the variables are cointegrated. According to the linear long run coefficients, oil production, FDI inflows and economic growth both have a positive and significant relationship with CO2 emissions, implying that they deteriorate environmental quality in OPEC countries, while renewable energy has a negative relationship with CO2, implying that increasing renewable energy improves environmental quality. The asymmetric findings prove that positive and negative shocks of oil production exert a positive effect on carbon emissions in short run and long run. Research limitations/implications To begin with, the empirical assessments do not include all OPEC member nations; researchers are advised to resolve this constraint by looking at the economies of other OPEC members. Albeit the lack of data for other energy sources may serve as another constraint of this research, future research is expected to broaden the current framework via other energy sources such as nuclear, electricity, biomass, solar as well as wind. Originality/value The research adds to the body of knowledge as many of the prevailing studies in the literature failed to look at the asymmetric effect of oil production on the quality of environment. This is another gap in the literature that the current study is set out to fill. This study adds oil production as an explanatory variable and helps to extend the existing literature for OPEC countries, which could propose a solution to deal with ensuing environmental issues.


Author(s):  
Luohui Ouyang ◽  
Qingzhen Bi ◽  
Hua Chen ◽  
Hai Shang ◽  
Li-Min Zhu

Abstract Blisks suffer from flutter, a self-sustained vibration caused by aerodynamic coupled forces. This instability could cause serious damage to the blades and the machine. Flutter stability is usually analyzed based on the eigenvalue method in the aspect of the linear structural dynamic system, which transforms a dynamics stability analysis into a point of equilibrium in an infinite time scale. However, in reality, most of the blisk vibrations arise on a finite time horizon. The transient vibration amplification may cause serious damage. This paper proposes a transient flutter stability analysis method in a finite time for structural mistuned blisk based on the energy growth method. Firstly, two common blisk models coupled aerodynamic force with different complexity are built, and are all expressed in the state space representation. A novel energy growth method is then employed to analyze the transient stability and to find the maximum energy growth of the models. The optimal initial condition which leads to the maximum energy growth is obtained. A new flutter stability criterion is developed to consider the transient stability based on the energy growth method and the infinite time stability based on the eigenvalue method. The new transient stability method is verified by two numerical studies. It is found that the structural mistuned blisk model which is traditionally predicted stable still has a transient instability in a finite time due to the non-normal property of the dynamic state matrix.


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