Polyethylene Glycol/Rice Husk Ash Shape-Stabilized Phase Change Materials: Recovery of Thermal Energy Storage Efficacy via Engineering Porous Support Structure.

This study focuses on modifying the porous structure of acid-treated rice husk ash (ARHA) to enhance the thermal energy storage capacity of poly(ethylene glycol) (PEG) confined within shape-stabilized phase change materials. The modification process involved a cost-effective sol-gel method in which ARHA was initially dissolved in an alkaline solution and subsequently precipitated in an acidic environment. ARHA, being a mesoporous SiO-based material with a high surface area but low pore volume, had limited capacity to adsorb PEG (50%).

Using Carbonized Cotton Fabric Waste to Prepare Poly(ethylene glycol) Composite Phase Change Materials with Improved Thermal Conductivity and Solar-to-Thermal Conversion.

Poly(ethylene glycol) (PEG) boasts excellent thermal energy storage capabilities but lacks efficiency in thermal conductivity and solar absorption. Simultaneously, the escalating concern surrounding the substantial volume of discarded cotton fabric underscores environmental issues. In this study, we devised composite phase change materials (PCMs) by embedding PEG into a carbon cotton material (CCM), varying PEG content from 50 to 80%, and conducted a comprehensive analysis of their thermal properties and solar-to-thermal conversion.

Polyethylene Glycol Confined in SiO-Modified Expanded Graphite as Novel Form-Stable Phase Change Materials for Thermal Energy Storage.

Form-stable phase change materials (FSPCMs) composed of poly(ethylene glycol) (PEG) encapsulated in SiO-modified expanded graphite (EG@SiO) were prepared and investigated for thermal energy storage behaviors. The modification of SiO on EG was done using a simple sol-gel method, and then the resulting EG@SiO was introduced to confine PEG at varying content (60-90 wt %). Surface properties (including microstructure, morphology, and functional groups), PEG adsorptivity, leakage-proof ability, and thermal energy storage of the prepared materials were thoroughly characterized and discussed.

Polyethylene glycol/fumed silica composites as shape-stabilized phase change materials with effective thermal energy storage.

Shape-stabilized phase change materials (SSPCMs), adopting polyethylene glycol (PEG) as the phase change material (PCM) confined in fumed silica (FS) as the porous support, and their thermal energy storage properties were thoroughly characterized with varying PEG contents, 60-90 wt%. Given a highly interconnected porous structure and a high porosity (88%), FS offered plenty of cavities to confine a large amount of PEG with interactions such as surface tension, capillary, and interfacial hydrogen bonds (H-bond). The interfacial H-bonds negatively affected the crystallinity of PEG and decreased the thermal energy storage capacity, which could be relieved by a large content of confined PEG.

Quadcopter UAVs Extended States/Disturbance Observer-Based Nonlinear Robust Backstepping Control.

A trajectory tracking control for quadcopter unmanned aerial vehicle (UAV) based on a nonlinear robust backstepping algorithm and extended state/disturbance observer (ESDO) is presented in this paper. To obtain robust attitude stabilization and superior performance of three-dimension position tracking control, the construction of the proposed algorithm can be separated into three parts. First, a mathematical model of UAV negatively influenced by exogenous disturbances is established.