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The acceleration of the energy transition away from traditional energy systems depends on the inclusion of H2 in energy plans. Using biomass to produce hydrogen energy holds significant promise in the field of renewable energy. This article explores the history of biomass as a sustainable energy source and highlights the important role of hydrogen energy. Various biomass hydrogen conversion technologies, including thermochemical, biological, electrochemical, and hybrid processes, are discussed and compared to other renewable energy sources. Given hydrogen energy inclusion into the energy mix, comparisons are made between methods of biomass-to-hydrogen conversion in terms of cost per kg of H2, power consumption in kWh as well as feedstocks utilized for hydrogen production, and their strengths and weaknesses. Case study applications of these conversion methodologies are highlighted and their strengths as well as limitations are addressed in the course of discussion. This article provides an in-depth look at the prospects and challenges of biomass hydrogen production, providing a review of the research literature, insights into efficiency improvements, level of advancement technology, and catalyst development. The role of catalysts, machine learning, and artificial intelligence along with other factors for improving hydrogen production were discussed. Challenges such as food supply, techno-economic constraints, environmental impact, and energy consumption have all been examined. The article concludes by highlighting current applications, prospects, and the overall importance of biomass hydrogen in transportation, business processes, and policy changes. [ABSTRACT FROM AUTHOR]

This study investigates the impact of temperature on the tribological performance of duplex layer CrN/DLC and nano-multilayers DLC-W coatings deposited using hybrid PVD-PECVD techniques on carburized and hardened 16MnCr5 discs cut from internal combustion engines valve tappets. Reciprocating dry sliding experiments were conducted at 25 °C, 150 °C, 200 °C, and 250 °C to analyze the high-temperature tribological behavior of the coatings. The wear mechanisms were characterized using SEM, EDS mapping, Raman spectroscopy, and nanoindentation. The lowest coefficient of friction was obtained for CrN/DLC at 25 °C. The CrN/DLC coefficients of friction (COF) increase with temperatures due to increasing adhesive wear. Similarly, DLC-W exhibited a comparable trend with increasing temperature from 25 °C to 250 °C. Both coatings' wear resistance decreased with higher temperatures due to the transformation of sp3 C bonds to sp2 C bonds, facilitating the plastic deformation of the coatings and afterward of the substrate. The CrN/DLC displayed superior wear resistance to the DLC-W coating across all temperatures. The DLC-W multilayer coating showed poor wear resistance above 150 °C, being completely removed during the testing. Compared to both coatings, the uncoated 16MnCr5 discs exhibited higher coefficients of friction and wear rates at all temperatures. Predominant wear mechanisms observed in the coated discs were adhesive and abrasive. The study revealed a decrease in the coatings' structural and mechanical properties with rising temperatures. Hard abrasive WC particles were identified as contributing to increased wear rates in the multilayer DLC-W coatings. [ABSTRACT FROM AUTHOR]

The focus of this study is to propose statistical models for predicting wear and coefficient of friction of the 16MnCr5 steel valve tappet using the analysis of variance (ANOVA). The 16MnCr5 steel valve tappet was fabricated from a steel strip and thermochemically treated by carburizing, quenching, and tempering. Under dry conditions, tribological tests were performed for 16MnCr5 steel valve tappet with a ball-on-plane configuration in a reciprocating slide using an Optimol SRV® v4 device. Subsequently, the results of the coefficient of friction (COF) and the wear rate were then analyzed using the ANOVA. Regression analysis was used to derive the predictive equations for both friction coefficient and wear rate. The applied load was found to be the most significant parameter affecting the COF and wear rate. The proposed statistical models has 88 - 92% percent reliability. These models can be beneficial for predicting the tribological operating conditions for the 16MnCr5 steel valve tappet to avoid premature failure within the tested load and temperature conditions. [ABSTRACT FROM AUTHOR]