Novel thermal energy storage materials were synthesized from graphene-decorated silica (SG) and stearic acid (SA) by vacuum impregnation method. Three kinds of SG (SG₁, SG₅, and SG₁₀) were prepared by decorating silica with different contents of graphene and were then used to stabilize SA to prepare SA/SG₁, SA/SG₅, and SA/SG₁₀ composites. The structures and thermal energy storage performances of the SA/SG composites were investigated. It is of interest that the thermal energy storage behaviors of the SA/SG composites were dramatically changed with different contents of graphene, presenting more than one endothermal or exothermal peak in the differential scanning calorimetry (DSC) curves while pure SA had only one. The SA in SA/SG₁ and SA/SG₅ showed higher crystallinity (F_c, 84.44% and 84.39%) and greater effective energy storage per unit mass (E_ef, ∼150 J g⁻¹) than that of SA in SA/SG₁₀. These thermal energy storage behaviors and properties were revealed to be related to the pore structures of the SG. The thermal stability of the SA/SG composites was analyzed by a thermogravimetric analyzer (TGA), and the SA/SG composites have good thermal stability. Addition of graphene was beneficial to the enhancement in thermal conductivity of the SA/SG composite, which could reach 0.90 W m⁻¹ K⁻¹, 1.05 W m⁻¹ K⁻¹, and 1.12 W m⁻¹ K⁻¹ for SA/SG₁, SA/SG₅, and SA/SG₁₀, respectively; and were 246%, 304%, and 331% higher than pure SA, respectively. SA/SG₅ has potential for application in thermal energy storage, especially in thermal gradients due to it having both high E_ef and thermal conductivity.

Many efforts have recently been dedicated to developing smart sockets that seek to provide insights into the reduction of standby energy waste coupled to electric appliances. However, not all technical solutions consider the techno-economic benefits in the development. This research presents a hardware solution based on STM32F103 (STM32F103 devices use the Cortex-M3 core, with a maximum CPU speed of 72 MHz) for the development of an energy-efficient smart socket to address the standby energy waste of household electric appliances and associated economic losses. Input-output analysis on monitored voltage and current was employed to assess the performance and examine the precision of the developed system. As it was targeted at facilitating easier operation, the smart socket was developed to be compatible with other remote controllers of household electric appliances. Experimental results indicated that the developed system could measure voltage values accurately to avoid overvoltage for security protection. The measuring unit could monitor current values with high precision to support the energy-saving control. A functional testing was conducted on the prototypes with a lifecycle assessment employed to validate the economic attractiveness of the developed system. Results indicated that the system is user friendly and cost-effective as no extra wiring required and network environment independent. Indeed, indirect fruits, such as lifespan extension and safety enhancement, could also be achieved for appliances.

The microstructure, low-cycle fatigue property, and fracture behavior of as-received and aluminized steel were investigated at room temperature, respectively. The results reveal that the aluminized layer is mainly composed of three layers: (I) the external Al₂O₃ layer, (II) the transition Fe-Al mesophase layer, and (III) the diffusion layer with AlFe and AlCrFe phase. The microhardness of as-received steel lower than that of aluminized steel until the distance from aluminized layer is greater than 150 μm. Compared to the original steel, the aluminized steel exhibits lower stress amplitude and fatigue life, which is correlated to the surface integrity. According to the Coffin-Manson relationship, the fatigue-ductility coefficients for as-received and aluminized steel is 4.347 and 3.528, respectively. Fractographic analysis reveals that the fatigue cracks tend to nucleate at the coating and propagate through the grain boundaries apace.

Understanding the mineralogical and chemical characteristics of stone coal is imperative for exploring the thermal storage characteristics of stone coal. Two types stone coal (SC_wt and SC_hc) were sampled from the pond of a stone coal mine in Henan province (China), and the chemical composition, phase composition, and thermal behavior of the stone coal were investigated. Furthermore, the petrography of the stone coal was studied in detail. The mineral phases of the stone coal were quartz, kaolinite, roscoelite, and goethite, as distinguished by reflected light microscopy and further proven by scanning electron microscope-energy dispersive spectrometer (SEM-EDS). The thermal conductivity of SC_wt was 0.19 W m⁻¹ K⁻¹, while that of SC_hc was 0.24 W m⁻¹ K⁻¹. Stearic acid (SA) was blended with SC_wt and SC_hc to prepare SA/SC_wt and SA/SC_hc composites via an impregnation method, respectively. The thermogravimetric (TG) curves show that the loading capacity of SC_hc, at 17.40%, is higher than that of SC_wt (16.63%). The thermal energy storage capacities of SA/SC_wt and SA/SC_hc composites were 29.21 J g⁻¹ and 33.02 J g⁻¹ according to a differential scanning calorimetry (DSC) analysis. Therefore, SC_hc is a potential candidate for thermal storage applications due to more obvious thermal storage characteristics, including higher thermal conductivity and loading capacity.

Microstructures and mechanical properties of Cu-35Ni-15Al alloy in cast and porous states were studied by scanning electron microscopy and compression tests. The influence of porosity, deformation temperature and loading rate on mechanical properties of the two kinds of alloys was investigated. The results show that the as cast alloy and porous alloys have almost the same phase constitution: Cu rich phase, Ni rich phase and K intermetallics. The yield strength of porous alloys increases continuously with decreasing porosity, the relationship between porosity and yield stress follows Gibson-Ashby equation. With decreasing deformation temperature, the yield strength of as cast alloy and porous alloy increase. With the increase of loading rate, the yield strength of these alloys shows an increasing trend. After compression, the microstructure of as cast alloy is more uniform, and porous alloys are more prone to have localized deformations.