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Simulation Approaches for Supporting Microservice Architectures: A Systematic Review

2026-05-23T02:00:37Z

Title: Simulation Approaches for Supporting Microservice Architectures: A Systematic Review Authors: Asim, A; Ali, N Abstract: ... Description: ...

Assessment of Monel 400 corrosion in hydrofluoric–hydrochloric acid condensation environments for condensing heat exchangers

2026-05-23T02:00:50Z

Title: Assessment of Monel 400 corrosion in hydrofluoric–hydrochloric acid condensation environments for condensing heat exchangers Authors: Stathopoulos, V; Pandis, PK; Zarkadoulas, A; Nanou, P; Fragkoulis, D; Poškas, R; Sirvydas, A; Poškas, P; Jankaukas, J; Jouhara, H Abstract: This study assesses Monel 400′s corrosion behavior in liquid and vapor phases in hydrofluoric (HF), hydrochloric (HCl), and mixed HF-HCl acid environments. Through mass loss testing and electrochemical measurements, the alloy’s degradation was evaluated under varying acid concentrations, temperatures, gas atmospheres (N₂, O₂), and metal ion contaminants (Cu²⁺, Fe³⁺). Electrochemical measurements (ASTM G59/G102) and mass loss (ASTM G31/G1) were used for corrosion testing. The findings demonstrate that corrosion rates are considerably increased by vapor-phase exposure, especially in combined HF-HCl vapors (up to 0.8 mm·y⁻¹), because of combined fluoride and chloride chemical attack. Improved anodic dissolution and decreased passivation are confirmed by electrochemical data, particularly when oxidizing conditions (O₂) and Cu²⁺ and Fe³⁺ ions are present. Significant surface deterioration, dealloying, and the development of corrosion products rich in fluoride and chloride were discovered by SEM/EDS investigations. The addition of CuCl₂ and FeCl₃ changed the surface chemistry and increased localized corrosion. Similar degradation trends were shown by industrial validation in a condensing heat exchange unit employing Monel 400, where concentrated acidic condensates promoted rapid material loss and corrosion deposits consisting of chlorides. The findings emphasize the limitations of Monel 400 in HF-HCl systems, notably under vapor-phase and oxidizing conditions, and propose mitigation measures such as alternate Ni-Cr-Mo alloys, protective coatings, and oxygen exclusion to improve durability in harsh fluorinated environments. Description: Data availability: Data will be made available on request.

The influence of thermal radiation absorption on the interaction of transient transfer processes for a water droplet evaporating in a high-temperature gas flow

2026-05-23T02:01:00Z

Title: The influence of thermal radiation absorption on the interaction of transient transfer processes for a water droplet evaporating in a high-temperature gas flow Authors: Miliauskas, G; Maziukiene, M; Poškas, R; Puida, E; Jouhara, H Abstract: This work presents a study of transient transfer processes of water droplets evaporating in flue gas, including spectral radiation absorption and droplet slip. The results of numerical modelling of condensation, transitional and equilibrium evaporation regimes of water droplets in flue gas at temperatures ranging from 633 to 1833 K are presented. The modelled radiative transfer is based on geometrical optics theory. Convective heating and evaporation of the droplet are defined by the empirical Clift correlation for Reynolds numbers Re < 400. The interaction between transient processes and the dependence of the physical and optical spectral properties of a warming droplet on temperature are taken into account. The numerical iterative scheme defining the average instantaneous temperature of the droplet’s surface and working according to the fastest descent method is based on the balance of heat fluxes. The influence of Stefan flow, evaluated by the Spalding heat- and mass-transfer parameters, is made universal for different droplet phase change regimes by carefully assessing the dynamics of the temperature gradient within the droplet. It was verified that the competing effects of droplet slipping and the absorption of radiation are essential for the interaction between droplet transfer processes. The internal heat transfer in a droplet is affected by absorbed radiation and influenced by water circulation. Due to the effect of absorbed radiation, the evaporation rate of a large water droplet more than doubles in flue gas at 818 K and increases up to fourfold at 1133 K. These simulation results agree with the experimental data.

An FPGA-Calibrated Modulo ADC for High-Dynamic-Range Signal Acquisition

2026-05-23T02:00:49Z

Title: An FPGA-Calibrated Modulo ADC for High-Dynamic-Range Signal Acquisition Authors: Zeyuan, L; Yan, W; Gan, L; Li, G; Hongqing, L Abstract: Conventional analog-to-digital converters (ADCs) suffer from irreversible clipping when input amplitudes exceed their fixed full-scale range. Modulo ADCs address this by folding the input signal prior to quantization; however, stable hardware operation under deep-folding conditions and experimental validation of algorithmic recoverability remain outstanding challenges. This paper presents a calibrated FPGA-based modulo ADC platform in which a finite state machine with multi-bit update control governs folding dynamics, replacing instantaneous comparator-triggered feedback to ensure deterministic and stable operation. A controlled under-compensation calibration strategy converts fold-dependent threshold mismatch and oscillatory instability into a bounded constant residual, enabling reliable folding at high folding depths. The platform achieves a dynamic range expansion exceeding two orders of magnitude while maintaining signal fidelity comparable to that of the standalone ADC. Experimental validation across diverse waveforms confirms robust signal acquisition and demonstrates the practical feasibility of dynamic-range extension using modulo sampling principles.