In this letter, we measured the nanoscale thermal radiation between a microsphere and a substrate which were both coated with thick gold films. Although gold is highly reflective for thermal radiation, the radiative heat transfer between two gold surfaces was demonstrated to be significantly enhanced at nanoscale gaps beyond the blackbody radiation limit due to the tunneling of non-resonant evanescent waves. The measured heat transfer coefficient between two gold surfaces agreed well with theoretical prediction. At a gap d ¼ 30 nm 6 5 nm, the heat transfer coefficient between two gold surfaces was observed to be as large as $400 W/m 2 ÁK, much greater than the blackbody radiation limit ($5 W/m 2 ÁK). When the gap size between two objects is smaller than the dominant thermal wavelength at the temperatures of the objects, photon tunneling can significantly enhance the radiative heat transfer beyond Planck's law of blackbody radiation. Cravalho et al. 1 theoretically investigated the enhancement of thermal radiation between two dielectrics at small separations. Polder and van Hove 2 established a theoretical approach to calculate the near-field radiation between metallic surfaces based on fluctuational electrodynamics theory developed by Rytov 3 that became the foundation for future investigations. This theoretical framework has been extensively used subsequently by many groups to study the near-field radiation between the surfaces of dielectrics, 4,5 semiconductors, 6 and thin films. 7 A number of experiments were also reported to measure the near-field thermal radiation between two parallel plates or between a small tip and a flat substrate. Domoto et al. 8 and Kuteladze et al. 9 investigated the radiative transfer between two parallel metallic surfaces at cryogenic temperatures. Hargreaves 10 carried out the experiments between two metallic films of chromium at room temperature and showed the enhanced heat transfer around 1 lm. Xu et al. 11 measured the radiative transfer between a deformed indium surface and a small gold surface but did not conclusively confirm near-field effects. Hu et al. 12 measured the radiative heat transfer between two glass plates and observed the radiative heat transfer exceeding the predictions of the Planck law by 35% when the two plates were separated by $1 lm. Very recently, Ottens et al. 13 measured the radiative heat transfer between two macroscopic planar sapphire surfaces with a separation down to several micrometers around room temperature. Kittel et al. 14 measured the radiative heat transfer between a scanning probe microscope (STM) tip and a flat substrate. The saturation of heat flux was observed at extremely small distances ($10 nm). They attributed this phenomenon to spatial dispersion effects and the contribution of the infrared magnetic dipole component.We have developed over the last few years a technique to measure the near-field radiation between a microsphere and a substrate at nanoscale gaps, using a bi-material atomic force microscope (AFM) cantilever. 15,16 The n...

Metal-organic framework (MOF) nanomaterials offer a wide range of promising applications due to their unique properties, including open micro- and mesopores and rich of functionalization. Herein, a facile synthesis via...

The alternative electric vehicle for delivery (E-Trike) is a developing three-wheel electric vehicle for goods delivery. Small size and its three-wheel mobility are required for flexible manoeuvrability on urban space due to traffic, parking and alley road. In this study, three different Alpha frames (Alpha-0, Alpha-1, and Alpha-2) of E-Trike vehicle are analysed using numerical simulation LS-DYNA. This study is conducted to obtain the modal response E-Trike vehicle. Eigenvalues of dynamics properties are investigated to avoid a resonance on excitation frequency. LS-DYNA implicit simulation used for simulating quadrangular shell element for the surface geometry of the frames. Boundary conditions are applied to the steering and suspension joints represent the real field. The result shows the amplitudes and the natural frequencies of Alpha frames. Bending mode and torsion mode can be determined. Based on the simulation, there is a pattern of vibration modes. Alpha-2 which is the latest version of three configurations has better response on vibration modes. There is about 3% reduction of vibration amplitude at Alpha-2 than Alpha-0 and Alpha-1. Natural frequency response for each mode occurs at similar range. Furthermore, a shifted natural frequency of Alpha-2 combination mode occurs due to addition of the stretched frame.

Temperature management for battery packs installed in electric vehicles is crucial to ensure that the battery works properly. For lithium-ion battery cells, the optimal operating temperature is in the range of 25 to 40 °C with a maximum temperature difference among battery cells of 5 °C. This work aimed to optimize lithium-ion battery packing design for electric vehicles to meet the optimal operating temperature using an air-cooling system by modifying the number of cooling fans and the inlet air temperature. A numerical model of 74 V and 2.31 kWh battery packing was simulated using the lattice Boltzmann method. The results showed that the temperature difference between the battery cells decreased with the increasing number of cooling fans; likewise, the mean temperature inside the battery pack decreased with the decreasing inlet air temperature. The optimization showed that the configuration of three cooling fans with 25 °C inlet air temperature gave the best performance with low power required. Even though the maximum temperature difference was still 15 °C, the configuration kept all battery cells inside the optimum temperature range. This finding is helpful to develop a standardized battery packing module and for engineers in designing low-cost battery packing for electric vehicles.

This paper demonstrates the design of an electric trike’s energy management system for a goods delivery service via various possible component configurations. A model of the energy management system was first developed based on general engineering vehicles’ equations using Matlab software. Various component configurations, such as the usage of two battery types (lithium iron phosphate (LFP) and lithium nickel cobalt aluminum oxide (NCA)), implementation of three braking strategies (full mechanical, parallel, and series strategies), the presence of a range extender (RE), and various masses of range extenders were simulated by using the model. The driving cycle of the e-trike as input data in the simulation was obtained by driving the vehicle around Bandung City. Speed, distance, and elevation were obtained by using GPS-based software. The simulation results showed that the most efficient and effective component configuration was to use the serial regenerative braking strategy with no RE equipped. This configuration achieved an efficiency of 18.07 km/kWh. However, for a longer route, the usage of a 20-kg RE was required to prevent the state of charge drop below 30%. The NCA with serial regenerative braking and 20-kg RE had an efficiency of 17.47 km/kWh for the complete route.