• Energy Research
• 2021-2025close
• Closed Access close
• Embargo close
• FR close

The growing global awareness of social and environmental issues has led investors to prioritize sustainable investments. This study examines the relationship between ten Islamic and conventional sector indices, which include stocks screened for environmental, social, and governance (ESG) factors, across three energy-related fields: renewable energy, energy efficiency, and oil equipment and services. Using a quantile cross-spectral approach, this research finds a high level of long-term synchronization among all energy-related sectors and indices. However, as markets shift from bearish to bullish, the current relationship between energy-related sectors and Islamic and conventional indices weakens. To support the findings in this research and investigate potential financial implications, this investigation applies a causality-in-quantiles approach. The research in this study shows a bidirectional causal relationship between conventional and Islamic indices, particularly in the energy efficiency sector during bearish market conditions. At lower tails, ESG market indices are found to cause renewable energy products, suggesting a hedging mechanism. The findings of this study assert that investments that do not possess any ESG shortcomings are imperative for effectively bolstering renewable energy companies and fostering opportunities for energy efficiency. These conclusions hold considerable ramifications for energy policymakers as they strive to devise more robust financial mechanisms that can provide substantial support to the burgeoning green sector.

This paper focuses on mixed [Formula: see text] fuzzy maximum power point tracking (MPPT) of photovoltaic (PV) system under asymmetric saturation and variations in climatic conditions. To maximize the power from the PV panel array, the DC–DC boost converter is controlled by its duty ratio which is practically saturated between 0 and 1. MPPT based on conventional control presents the problems of oscillations around maximum power point (MPP) and divergence under rapid climatic changes. In order to attenuate the effect of atmospheric condition variation and take into account asymmetric saturation of the duty ratio, we propose a novel robust saturated controller based on both [Formula: see text] performances and Takagi-Sugeno (T-S) representation of PV-boost nonlinear system. Within this approach, the nonlinear PV-boost system and its reference are first described by T-S fuzzy models. Second, the saturation effect is represented by a polytopic model. Then, a fuzzy integral state feedback controller is designed to achieve stable MPPT control. Based on Lyapunov function, the mixed [Formula: see text] stabilization conditions are derived in terms of linear matrix inequalities (LMIs). The optimization of the attraction domain of closed-loop system is solved as a convex optimization problem in LMI terms. Finally, the efficiency of the proposed controller under irradiance and temperature variations is demonstrated through the simulation results. The comparison with some existing controllers shows an improvement of MPPT control performance in terms of power extraction.

Abstract Intentional frequency mistuning referred to as detuning is known to be an effective mean to prevent aeroelastic flutter in gas turbines. The Coriolis effect, which is usually discarded, can reduce the mistuning effects and therefore compromise the stabilizing effect of detuning with respect to flutter. This paper presents an original study of the influence of the Coriolis effect on the aeroelastic stability of a single-piece bladed disk (blisk), which made it possible to highlight for the first time the complex interactions between flutter, mistuning, and the Coriolis effect. The blisk is modeled with a lumped parameter model and the aeroelastic self-excitations using Whitehead's theory. A genetic algorithm is used to determine the best detuning pattern to stabilize the flutter-prone blisk. The results show that if the detuning pattern is identified without taking the Coriolis effect into account, the detuned blisk can still be prone to flutter. The key driver of this loss of stability is the frequency separation of the modes resulting from the Coriolis effect, which decreases the mode interactions that are required to stabilize the system. This article demonstrates the need to consider the Coriolis effect when studying the aeroelastic stability of cyclic structures with flexible disk and blade-disk coupling. By doing so, it is shown that a higher level of detuning is needed to compensate the adverse effects of Coriolis and ensure stability to flutter.

Adenomyosis is characterized by the presence of ectopic endometrial tissue within the myometrium. Treatment options ranges from use of non-steroidal anti-inflammatory drugs and hormonal suppression for symptomatic relief, to endometrial ablation or even hysterectomy. In this paper we report the case of successful ultrasound-guided aspiration of focal adenomyosis with intracavitary alcohol instillation in a young patient with symptomatic juvenile cystic adenomyoma. This is the second report of the treatment of sclerotherapy by alcohol instillation, which may be considered as an alternative modality in treating the cases of symptomatic adenomyoma.

This study presents the numerical development of a generator–rectifier combined component (called a “combined-generator”) composed of plate heat exchangers, designed and meant to be integrated in a single-stage ammonia–water absorption cooling system. Investigations are made to find the most compact and efficient design. Numerical simulations are presented describing parameters such as the ammonia fraction in the vapor produced and the combined generator efficiency as a function of the inlet temperatures or mass flow rate of the heat transfer fluid. The combined generator produces vapor with a high ammonia mass fraction and high mass efficiency for a solution inlet temperature range of [315–320 K] and a mass flow rate of the heat transfer fluid between [0.4 and 0.6 kg.s−1]. The impacts of the length and number of plates as well as the adiabatic/heated ratio of the plates are also examined. The ammonia fraction increases with the increase in the adiabatic/heated ratio, and the combined generator efficiency increases with the increase in the plate aspect ratio of length/width. The proposed system is developed to be operated in compact and medium-capacity absorption chillers (approximately 5 kW cold) for air-conditioning.