In this paper, a new numerical scheme for optimal control of jump-diffusion model is proposed by using stohastic Runge-Kutta (SRK) method. After discretizing the problem with the SRK method, optimality conditions are obtained by using the discretize-then-optimize approach. It is shown that the constructed numerical scheme is similar to the continuous optimality conditions obtained by using the Hamilton-Jacobi-Bellman equations. Moreover, a numerical scheme for control problems of Ornstein-Uhlenbeck (OU) with jump is presented as a simple version of jump diffusion equations. Some numerical examples are chosen to show the efficiency of the theoretical results.
This paper presents a model for energy conversion and derives an exergy balance equation for single-step chemical reactions in flames. The model can evaluate changes in chemical and thermodynamic energy, the loss of available energy, and thermodynamic efficiency. By combining this model with a detailed chemical mechanism, the effects of pressure, temperature, and the equivalence ratio on exergy efficiency are evaluated. In addition, important chemical reactions and substances for energy conversion can be identified. Furthermore, this model is applied to the thermodynamic analysis of an inverse-diffusion ethylene (C2H4) flame. A systematic study, including entropy generation, chemical analysis, and exergy analysis, is carried out. The combustion and thermodynamic characteristics of the inverse-diffusion C2H4 flame are investigated. The results indicate that increasing the temperature of the medium is a relatively direct and effective way to improve exergy efficiency. The pyrolysis and oxidation of C2H4 are the main sources of the chemical entropy generation rate (EGR), while multi-carbon reactions contribute very little. The pathways C2H4 -> C2H3 -> CH2 -> (CH2O or CH) -> HCO -> CO are the most important for the chemical EGR. From the inner to the front of the flame, thermodynamic equilibrium is established, and a low temperature is a more significant factor limiting reactions than reactant concentration. Five reactions (R12, R48, R60, R77, and R55) determine the energy conversion efficiency of the entire flame. These reactions account for more than 95 % of energy conversion and should be emphasised when optimising combustion.
The manufacturing of Ti6Al4V sheet metal components for aerospace applications is strongly limited by the poor formability of the alloy at room temperature, making conventional cold forming techniques unsuitable for manufacturing such components. To overcome these limitations, hot stamping techniques based on controlled thermo-mechanical conditions have been developed to enable the production of sheet metal parts with moderately complex geometries. This paper presents a comprehensive review of hot stamping processes operating at quasi-static strain rate (10−3 –10−1 s−1) within the warm temperature regime (0.3Tm – 0.5Tm), aiming to clarify process regimes, deformation mechanisms, and current technological limitations. Particular attention is given to the influence of key process parameters such as temperature, stamping velocity, and applied load on deformation behavior, microstructure evolution and mechanical performance. In addition, numerical modeling approaches based on finite element analysis are critically reviewed, including comparisons of material models, formability criteria, friction modeling, and thermo-mechanical coupling strategies employed in commercial simulation software. Lastly, the formation of alpha case, oxidation phenomena, and the subsequent pickling processes involved in the manufacturing of Ti6Al4V sheet metal components are discussed. Based on the reviewed literature, the advantages and limitations of different hot stamping techniques are compared, and practical tables are proposed to support efficient, sustainable, repeatable, and controllable process selection. Moreover, current research gaps are identified, particularly regarding tool lifespan, combined effects of hot stamping variables (temperature, stamping velocity and applied load) on formability, and the integration of microstructure-based simulation models, outlining directions for further investigation.
The biogenic synthesis of silver nanoparticles (AgNPs) using microalgae provides a sustainable alternative to conventional physicochemical methods. In this study, AgNPs were synthesized from the cell-free supernatant of the freshwater microalga Mychonastes sp. B1 and characterized by ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FE-SEM/EDS). The nanoparticles were predominantly spherical (15–55 nm), highly stable (ζ = − 42.8 mV), and appeared to be capped by extracellular polymeric substances. The biogenic AgNPs (GS-AgNPs) exhibited potent antibacterial activity, with minimum inhibitory concentrations (MICs) of 2.0 µg/mL against Staphylococcus aureus and 2.5 µg/mL against Pseudomonas aeruginosa, and significantly (p < 0.05) inhibited biofilm formation. Fibroblast viability remained at or above 80
The etiopathogenesis of pediatric obsessive-compulsive disorder (OCD) still remains unclear. Recent literature highlights the involvement of the kynurenine pathway (KP) in psychiatric disorders, particularly major depressive disorder (MDD). However, the potential role of KP in pediatric OCD has yet to be explored. This study aimed to compare serum levels of KP metabolites, including tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYNA), and quinolinic acid (QUIN), and inflammatory markers such as CRP, TNF-α, IL-6, IFN-γ, and TWEAK, in children and adolescents diagnosed with OCD with and without comorbid MDD, and healthy controls, after adjustments for potential confounding factors. Ratios reflecting KP enzyme activities (KYN/TRP, KYNA/KYN, QUIN/KYN) and the neurotoxic index (QUIN/KYNA) were also compared, alongside correlations between inflammatory markers and KP parameters. Serum levels of KP metabolites, TNF-α, IFN-γ, and TWEAK were determined using enzyme-linked immunosorbent assay, IL-6 via electrochemiluminescence immunoassay, and CRP via nephelometric method. A total of 107 drug-naïve participants aged 8-18 years were enrolled: 37 with OCD alone, 32 with OCD+MDD, and 38 healthy controls. Compared to the control group, KYN and KYNA levels, and KYN/TRP ratios were lower in the OCD group, while QUIN/KYNA ratios and TWEAK levels were higher. In the patient groups, IFN-γ and TWEAK were positively correlated with TRP, KYNA, QUIN, KYNA/KYN, and QUIN/KYN, but negatively correlated with KYN/TRP. These findings suggest, within a hypothesis-generating framework, that KP alterations related to immune dysregulation may play a role in childhood OCD pathogenesis, especially in non-comorbid forms or early stages.
