Abstract: Wearable thermoelectric generators (w-TEGs) rely on heat transfer between the human body and the surrounding environment to produce electrical power. Their performance depends strongly on how heat flows through the contact area between the skin and w-TEGs, through the thermoelectric legs, and toward the surrounding environment. This presentation provides an overview of the heat transfer processes that influence the operation of w-TEGs, including conduction within the device layers, convection at the external surfaces, and radiation exchange with the environment. The discussion highlights how these mechanisms affect the temperature differences available during real use and, consequently, the electrical output. The aim is to provide a clear perspective on the heat transfer processes that affect w-TEG performance and to outline approaches to improve their performance across different applications.

Abstract: Unmanned marine devices require long-term autonomous operation, yet limited onboard energy storage remains a critical challenge. In-situ wave energy harvesting offers a promising solution, but conventional pendulum harvesters suffer from narrow frequency bandwidth and poor adaptability to irregular excitations and variable sea states. This work presents two novel pendulum-based designs to address these issues. First, a magnetic multi-stable pendulum harvester creates multiple potential wells to enhance broadband response under multi-directional irregular waves, significantly improving output performance compared to traditional designs. Second, an origami-inspired deformable pendulum harvester enables dual-mode operation, with a fully expanded state for normal energy harvesting and a fully folded state for protection in harsh sea conditions. The folding mechanism is actuated pneumatically with low pressure requirements. Both concepts are validated through analytical modeling, numerical simulation, and field experiments. The proposed designs substantially improve the adaptability and robustness of in-situ pendulum wave energy harvesters, offering practical pathways for powering unmanned marine devices in diverse ocean environments.

Abstract: Dry reforming of methane (DRM) is a promising technology for converting greenhouse gases (CH4 and CO2) into syngas, but it is typically hindered by high energy barriers and rapid catalyst deactivation due to severe coking. This work presents a comprehensive study on designing advanced Ni-based catalysts to overcome these challenges through active site engineering and photothermal catalysis. First, we reveal the non-thermal effects of light on Ni/Ga2O3, where light irradiation reverses the electron transfer direction and generates hot electrons, effectively tuning the H2/CO ratio near unity by suppressing the reverse water-gas shift reaction. Second, moving to single-atom catalysis on NiSA/CeO2, we demonstrate that light irradiation reinforces the formation of the key anti-coking intermediate (CH3O*), achieving exceptional stability for over 230 hours at a low temperature of 472 °C. Third, we explore heteroatom doping strategies to stabilize active sites. Praseodymium-modified CeO2 (Ni/Pr-CeO2) is found to facilitate direct carbonate cleavage under light, significantly boosting CO yield, while Molybdenum-stabilized Nickel-oxo sites (NiMo/MgO) enable a "hydroxyl-mediated" pathway involving CH2OH intermediates, further lowering the activation temperature to 465 °C. Finally, we scale up these concepts to a concentrated-solar catalytic system using Ni-O4 coordinated sites on CeO2(100), achieving ultrahigh conversion (>93%) and light-to-chemical energy conversion efficiency (25.9%) with over 800 hours of durability. These findings collectively provide critical mechanistic insights into C-H/C-O bond activation and offer a multidimensional roadmap for developing sustainable, solar-driven C1 chemistry technologies.

Abstract: While a break accident occurs in the reactor, the spray system will spray dense droplet to depress temperature and pressure in the interior of the containment, the behavior of multi-droplet evaporation will be complicated by evaporation shielding effects. To investigate the phase change characteristics of dense droplets in motion, this article proposes a spray droplet evaporation model modified by Distributed Point Source Method (DPSM) based on the macroscopic characteristics of the "shielding effect" of droplet groups under different droplet numbers, droplet sizes, and other working conditions. Simultaneously, to investigate the intrinsic relationship between the multiple droplets evaporation characteristics under shielding effects and the droplet boundary layer, numerical simulations and experimental investigations were conducted on suspended double droplets in a linear arrangement with different droplet diameter, droplet spacing to diameter ratio (C), relative velocity and temperature difference working conditions. The research results indicate that: The shielding effect has a significant impact on droplet evaporation, with a minimum correction coefficient of 0.07. As the droplets becomes denser, the shielding effect tends to a stable value, and after correcting for the droplet group shielding effect, the spray calculation program can achieve better prediction. The same variation pattern of droplet evaporation rate was observed through experiments and numerical simulations, as the distance between two droplets increases, the mutual influence of evaporation between droplets decreases, and the evaporation rate of droplets increases. However, as the spacing increases, the evaporation rate gradually weakens under the influence of the spacing variation. The temperature boundary layer dimensionless thickness (δ*) progressively increasing in the direction of air flow. The average of δ* has a quadratic polynomial relationship with the diameter when the difference between the diameters of two droplets increases, the difference has a significant influence on Nusselt number. As the value of C increases, the average of δ* decreases in a quadratic trend, and the Nusselt number on downstream droplet surface increases but the difference decreases. In the sensitivity analysis of evaporation influencing factors, droplet diameter has the most significant impact.

Abstract: A potential enabler of a low carbon economy is the energy vector ammonia, which is a carbon free carrier with high energy density. Hence, it is proposed that ammonia, with its established transportation network and high flexibility, could provide a practical next generation system for energy transportation, storage and use for power generation. Therefore, previous studies and ongoing research are presented to use this chemical as a viable energy vector for power applications, emphasizing the challenges before implementation and commercial deployment is achieved at a larger scale. The talk covers fundamental research results on ammonia combustion are presented including ignition delay times, laminar flame speeds, species concentration profiles, oxidation chemistry, laminar and turbulent flames structures. Ammonia flame stabilization behaviors and emission characteristics are presented and discussed by using a gas turbine combustor. Injection and co-firing strategy in swirl combustors and the combustion enhancement will also be addressed. A better understanding on emission controls over the combustion on NOx mitigation and other techniques will be revealed.

Abstract: In nuclear power plant wet scrubbers and chemical plant bubble columns, where radioactive decay and exothermic reactions occur respectively, the liquid phase may experience continuous and uniform volumetric heating and have an obvious influence on the evaporation process. The existing research has predominantly focused on bubble evaporation under non-continuous heat sources or boundary heating conditions, but the mechanisms of bubble phase change under the unique thermal boundary of continuous uniform volumetric heating are still scare. This study investigates the migration and distribution characteristics of water vapor within bubbles under conditions of continuous uniform liquid heating, with particular focus on the effects of decay heat power. For volumetric heating powers increased by equal increments, the difference between the non-heating condition and the lowest heating power case exhibits the most substantial changes in bubble velocity, evaporation rate, and water vapor concentration near the gas-liquid interface. Specifically, the application of continuous uniform heating leads to an increase in near-interface vapor concentration, accompanied by significant decreases in both bubble velocity and evaporation rate. When comparing cases with heating powers separated by subsequent increments of the same magnitude, the vapor concentration and bubble velocity continue to rise, while the evaporation rate continues to decline, with the magnitudes of these variations being considerably smaller than those observed between the non-heating and the lowest heating power cases. These findings enhance the understanding of bubble phase change under continuous uniform heating and provide a theoretical basis for thermal-hydraulic safety analysis and design optimization of relevant industrial equipment.