Shell-Driven Localized Oxide Nanoparticles Determine the Thermal Stability of Microencapsulated Phase Change Material.

Not all encapsulation techniques are universally apt for every type of phase change material (PCM), highlighting the imperative for methodological precision. This study addresses the challenges of microencapsulated PCM (MEPCM) arising from the immiscible pairing of α-Al2O3 nanoparticles with Sn microparticles. The high-speed impact blending (HIB) dry synthesis technique is employed, facilitating large-volume production of Sn@α-Al2O3 MEPCMs. The resulting MEPCMs not only seamlessly endure 100 cycles of melting-solidification but also, with the strategic incorporation of a glass frit, exhibit remarkable thermal durability, withstanding up to 1000 melting-solidification cycles. Even under ultrafast thermal fluctuations, the α-Al2O3 shell remained resilient through 100 cycles. A marked reduction in supercooling is observed, which is attributed to the formation of SnO and SnO2 nanoparticles within the α-Al2O3 crystal lattice. The atomically resolved interface dynamics between SnO2 and α-Al2O3 play a pivotal role, lowering the energy barrier for Sn nuclei formation during solidification. This affects the accelerated Sn nucleation rate, effectively suppressing supercooling. Such insights offer a deeper understanding of the interplay between nanoscale crystal lattice imperfections and their implications for energy storage applications.

Assessment of the internal and external exposure risks to methylsiloxanes in communities near a petroleum refinery.

Methylsiloxanes (MSs) are widely used in industrial production and have attracted much attention due to their potential health risks to humans. MSs are present in emissions from petroleum refining, and it is therefore important to assess the health risks to residents living near refineries. In this study, we evaluated the pollution characteristics and human exposure risks of three cyclic MS (CMS) oligomers (D4-D6) in areas upwind and downwind of a petroleum refinery. The concentrations of total CMSs were 4-33 times higher in the downwind than upwind areas. At the same sampling site, the concentrations of CMSs were higher indoors than outdoors. The maximum concentration of CMSs was found in the indoor environment 200 m downwind of the petroleum refinery (75 µg/m3 in air and 2.3 µg/g in dust). The concentrations and detection rates of CMSs in plasma samples were higher in the downwind than upwind residents. Although residents living downwind of the petroleum refinery were a non-occupationally exposed population, they should be considered a highly CMS-exposed population because of their extremely high internal exposure doses. Inhalation exposure was the main source of CMSs in the plasma of these residents. When different exposure pathways were investigated, inhalation exposure was the major contributor to the average daily dose in residents of locations near the petroleum refinery, whereas the dermal absorption of personal care products was the major contributor at other sites. Although the overall risks of exposure to total CMSs were below the chronic reference dose for all exposure pathways, the combined joint toxic effects of various CMSs remain unclear. Further studies are therefore required to determine the exposure risks and subsequent health effects of CMSs for the residents of these areas.

Optimized Preparation of a Low-Working-Temperature Gallium Metal-Based Microencapsulated Phase Change Material.

Gallium has been considered for application in the thermal management of electronic equipment because of its high heat transfer ability and heat storage density. To address the issues of metal corrosion and leakage, a microencapsulation method, through which a stable corrosion-resistant ceramic shell can be formed from the liquid metal, is proposed. In this study, an optimized fabrication method for a microencapsulated phase change material (MEPCM) consisting of liquid-state Ga droplets, possessing high durability and heat storage density, is presented. A fabrication route comprising particle formation, hydrothermal treatment, and calcination is proposed. In particular, the thickness and crystal size of the GaOOH shell are controlled by changing the pH during hydrothermal treatment to produce a highly durable shell. The morphology and microstructure, phase composition, heat storage capacity, and durability of the prepared Ga-MEPCM are investigated. In addition, treatment conditions and the shell formation mechanism are analyzed. The results show that pH 9 is the most suitable shell-forming condition, at which the thickest Ga2O3 shell with the smallest crystal size can be produced, which is beneficial for ensuring durability. The MEPCM achieved 200 cycles without leakage and 300 cycles without shape deformation with a high heat storage density of 369.4 J·cm-3.

Study on temporary resolution for offshore marine oil spill emergencies based on remote sensing system.

Time is particularly critical for an oil spill occurring in the ocean as wind and current can rapidly spread the oil over a large area in a short time. Using the features of sensor surveillance system and mathematical trajectory models, the cooperation of surveillance and trajectory under oil spill emergency response is presented in this paper. Based on integration of equation simulating an oil spill trajectory, the method for remote-sensing application time (Te) has been described, and optimization of processing time described in the application time equation has been proposed. This contribution, which is integrated with remote-sensing and mathematical models, is expected to be a powerful tool for real-time contingency planning in the Dalian Xingang oil spill. According to these findings, the method allowed spills emergency alerts to make the best decision for choosing remote-sensing data, considering effective temporary resolution.

Association of virulent genotypes and phylogenetic origins of Helicobacter pylori with gastric cancer.

OBJECTIVE: To investigate the association between the genotypes, sequence variations and phylogenetic origins of strains of Helicobacter pylori with gastric cancer in Chinese patients. METHODS: Strains of H. pylori were isolated from patients with chronic gastritis and gastric cancer. Genotypes of the cagA and vacA genes were determined using polymerase chain reaction. Sequence analysis was used to detect variations in the 3' and 5' regions of cagA, and to detect known polymorphisms in cagE. A phylogenetic tree was constructed based on the analysis of seven housekeeping genes. RESULTS: A total of 67 strains of H. pylori were analysed. Nearly all strains of H. pylori carried cagA (65/67; 97.0%), an East Asia type of the cagA 3' region (63/65; 96.9%) and the vacA intermediate (i)1 genotype (65/67; 97.0%). None of the H. pylori strains examined had sequence variations in the 5' region of cagA or cagE. Phylogenetic analyses, however, revealed that strains of H. pylori from gastric cancer tended to cluster together. CONCLUSIONS: Virulent strains of H. pylori were highly prevalent, but virulent genotypes of H. pylori associated with gastric cancer were not detected in this geographical region.