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Article Robust Divergence-Based Tests of Hypotheses for Simple Step-Stress Accelerated Life-Testing Under Gamma Lifetime Distributions(Elsevier B.V., 2026) Balakrishnan, N.; Jaenada, M.; Pardo, L.Many 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. © 2026Article Citation - WoS: 6Citation - Scopus: 7Polyethyleneimine Functionalized Waste Tissue Paper@waste PET Composite for the Effective Adsorption and Filtration of Organic Dyes From Wastewater(Elsevier B.V., 2025) Radoor, Sabarish; Karayil, Jasila; Devrim, Yilser; Kim, HernThis study explores the potential of repurposing discarded plastic bottles and cellulosic paper waste to develop cost-effective and high-performance composites for dye removal applications. A novel composite, polyethyleneimine (PEI)-functionalized waste tissue integrated into waste polyethylene terephthalate (wPET) (PEIWT/wPET), was designed as an environmentally friendly adsorbent for wastewater treatment. Successful surface functionalization with PEI was confirmed through FTIR, EDX, and XPS analyses. The PEI-modified composite exhibited enhanced mechanical and thermal stability while demonstrating significantly improved dye adsorption/filtration performance. The composite was evaluated for the removal of both cationic (crystal violet, CV) and anionic (orange II, O II) dyes under optimized conditions; (10,000 mg/L and 1666 mg/L) adsorbent dosage, (11 and 1) pH, 10 mg/L initial dye concentration, and (180 min and 120 min) contact time for CV and O II respectively. Experimental results showed that PEIWT/wPET achieved maximum adsorption capacities of 3.94 mg/g for CV and 11.73 mg/g for O II, approximately five times higher than the unmodified composite (0.74 and 2.4 mg/g). Adsorption isotherm and kinetic studies indicated that the data aligned well with the Langmuir as well as Freundlich and pseudo-second order models. The membrane also exhibited filtration capability for both dyes, achieving a filtration efficiency of 78.69 % for anionic and 41.31 % for cationic dye separation. Overall, the PEIWT/wPET composite offers a promising, sustainable, and energy-efficient solution for the removal of organic pollutants.Article Fröbenius Expansions for Second-Order Random Differential Equations: Stochastic Analysis and Applications to Lindley-Type Damping Models(Elsevier B.V., 2026) Halim, H.; Kerker, M.A.; Boduroğlu, E.This 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(Ω) 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. © 2026 Elsevier B.V.Article Citation - Scopus: 2A Solution To Adhesion Problem of Oxide Thin Films on Zinc Selenide Optical Substrates(Elsevier B.V., 2017) Cosar,M.B.; Aydogdu,G.H.; Batman,H.; Ozhan,A.E.S.Zinc Selenide optical substrates have high transparency within the 0.5 to 14.0 μm wavelength range. This makes them an attractive candidate for multi band imaging applications in the optical components. In order to minimize reflection losses for visible, near-infrared and mid-infrared applications, Zinc Selenide lens are coated with multi-layered oxide thin films by physical vapor deposition method or Ion Beam Deposition. In this study, four-layer dual beam anti-reflective coating design at 1.064 μm and between 3.6 and 4.9 μm is applied using Ion Beam Deposition system directly on Zinc Selenide substrates. Because of solving the adhesion problem which is observed after the coating of oxides on Zinc Selenide substrates, they were treated at 300 °C for varying amounts of time before coating oxides. Treated samples were examined in terms of their roughness, contact angle, morphology, refractive index, transparency, crystallography and chemical composition. It is found that it is possible to manufacture durable oxide thin film coatings on Zinc Selenide, utilizing well designed pre-treatment processes. © 2016 Elsevier B.V.Editorial Special Issue: Computational Methods in System Reliability(Elsevier B.V., 2024) Tank F., Professor,; Eryilmaz S., Professor,[No abstract available]
