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Article Robust Divergence-Based Tests of Hypotheses for Simple Step-Stress Accelerated Life-Testing Under Gamma Lifetime Distributions(Elsevier, 2026) Balakrishnan, Narayanaswamy; Jaenada, Maria; Pardo, LeandroMany modern devices are highly reliable, with long lifetimes before their failure. Conducting reliability tests under actual use conditions may require therefore impractically long experimental times to gather sufficient data for developing accurate inference. To address this, Accelerated Life Tests (ALTs) are often used in industrial experiments to induce product degradation and eventual failure more quickly by increasing certain environmental stress factors. Data collected under such increased stress conditions are analyzed, and results are then extrapolated to normal operating conditions. These tests typically involve a small number of devices and so pose significant challenges, such as interval-censoring. As a result, the outcomes are particularly sensitive to outliers in the data. Additionally, a comprehensive analysis requires more than just point estimation; inferential methods such as confidence intervals and hypothesis testing are essential to fully assess the reliability behaviour of the product. This paper presents robust statistical methods based on minimum divergence estimators for analyzing ALT data of highly reliable devices under step-stress conditions and Gamma lifetime distributions. Robust test statistics generalizing the Rao test and divergence-based tests for testing linear null hypothesis are then developed. These hypotheses include in particular tests for the significance of the identified stress factors and for the validity of the assumption of exponential lifetimes.Article Regular AdS3 Black Holes From a Regularized Gauss-Bonnet Coupling(Elsevier, 2026) Alkac, Gokhan; Mesta, Murat; Unal, GonulWe obtain a three-dimensional bi-vector-tensor theory of the generalized Proca class by regularizing the Gauss-Bonnet invariant within the Weyl geometry. We show that the theory admits a regular AdS3 black hole solution with primary hairs. Introducing a deformation in the theory, a different regular AdS3 black hole solution is obtained. Charged generalizations of these solutions are given by coupling to Born-Infeld electrodynamics.Book Part Hydrogen Production: Electrolysis Methods(Elsevier, 2025) Celebi, C.; Altınışık, H.; Atak, Y.N.; Çolpan, C.; Devrim, Y.Electrolyzers are at the forefront of sustainable energy technologies, which are important in converting electrical energy into storable and transportable chemical energy. Electrolyzers enable the production of environmentally friendly green hydrogen using excess electricity from renewable sources, thereby reducing outage problems and facilitating grid balancing. Furthermore, using hydrogen as an energy carrier has great potential for decarbonizing hard-to-decarbonize sectors such as heavy industry, aviation and shipping. This chapter provides a comprehensive overview of electrolyzers, covering their basic principles, their various types and their significant importance in the transition to a greener energy environment. The chapter first discusses the basic operation of electrolyzers and explains the electrochemical processes involved in decomposing water molecules into hydrogen and oxygen gases. Each type of electrolyzer is discussed in detail, highlighting their unique features, efficiency, scalability, and technological advancements. Comparative analysis between electrolyzer types provides insights into their suitability for various applications and deployment scenarios. In conclusion, this chapter highlights the critical role of electrolyzers in enabling the hydrogen economy and advocates for continued research, development and deployment efforts to harness their full potential in moving towards a sustainable and carbon-neutral future. © 2025 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.Book Part Fuel Cell Energy Conversion(Elsevier, 2025) Ercelik, M.; Nalbant, Y.; Çolpan, C.; Ismail, M.S.Fuel cells are electrochemical devices that convert the chemical energy of the fuel into electrical energy directly. There are different types of fuel cells, which can be categorized according to their electrolyte type and fuel used. The performance of these fuel cells mainly depends on the materials of their components and the manufacturing method. In this chapter, an introduction to different fuel cell types, the materials and manufacturing methods that can be used for fuel cells, and characterization techniques are first presented. Then, the basic concepts and equations for the thermodynamics and electrochemistry of fuel cells are given. The principles of fuel cell stack design including the calculations of pressure drop within a flow field are discussed. Energy and exergy analyses of integrated fuel cells systems are also presented. This chapter also covers several illustrative examples and a case study on the mathematical modeling of fuel cells. © 2025 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.Book Part Clinical Development of Quinone-Based Drugs(Elsevier, 2024) Altuner, E.E.; Issa, G.; Ozalp, V.C.; Aldemir, O.; Torlak, Y.; Dar, U.A.This chapter provides a detailed explanation of the clinical investigations, pharmacological effects, and characteristics of quinone and quinone derivatives, along with references to pertinent sources. Although quinones have an oxygen group in their structure, they are quickly oxidized and interact with reactive oxygen species. This demonstrates how quinones work as drugs. Quinones and their derivatives are used as medications to treat a wide range of diseases, including cancer, lung, kidney, brain, and tumor disorders. Each of the following has effects on a different area of health; lapochols, anthraquinones, naphthoquinone and its derivatives, and other wide range of quinone derivatives are thoroughly explored in this chapter. © 2025 Elsevier Inc. All rights reserved.Article Fröbenius Expansions for Second-Order Random Differential Equations: Stochastic Analysis and Applications to Lindley-Type Damping Models(Elsevier, 2026) Zeghdoudi, Halim; Kerker, Mohamed Amine; Boduroglu, ElifThis paper develops a Frobenius series framework for the stochastic analysis of second-order random differential equations of the form Y(t) + A(t)Y(t) = 0, where the damping coefficient A(t) is a positive stochastic process and the initial conditions are square-integrable random variables. Assuming mean-square analyticity of A(t) in a neighborhood of the initial time, we establish existence and uniqueness of the solution in L2(Omega) and derive exponentially convergent truncation error bounds for the associated Frobenius expansion. The resulting series representation enables the numerical approximation of the probability density function of Y(t) via Monte Carlo simulation. To improve computational efficiency, a control variates strategy is incorporated for variance reduction. A comprehensive numerical study is conducted for a broad family of positive, right-skewed damping distributions, including the Lindley, XLindley, New XLindley (NXLD), Gamma-Lindley, Inverse-Lindley, Truncated-Lindley, Log-Lindley, and a newly proposed Mixed Lindley-Uniform model. The simulations illustrate how different tail behaviors and boundedness properties of the damping coefficient influence the stochastic dynamics and the accuracy of density estimation. Finally, stylized applications to option pricing and Value-at-Risk estimation are presented to illustrate how the Frobenius-based framework and control variates methodology can be embedded within standard uncertainty quantification workflows. Overall, the proposed approach provides a flexible and computationally efficient tool for the analysis of randomly damped dynamical systems.
