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Astrobiology
January 2025
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA.
Meteoritic impacts on planetary surfaces deliver a significant amount of energy that can produce prebiotic organic compounds such as cyanides, which may be a key step to the formation of biomolecules. To study the chemical processes of impact-induced organic synthesis, we simulated the physicochemical processes of hypervelocity impacts (HVI) in experiments with both high-speed C projectiles and laser ablation. In the first approach, a C beam was accelerated to collide with ammonium nitrate (NHNO) to reproduce the shock process and plume generation of meteoritic impacts on nitrogen-rich planetary surfaces.
View Article and Find Full Text PDFLangmuir
January 2025
Research Center for Water Resources and Interface Science, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.
The mechanism of the emulsion polymerization of styrene to polystyrene nanoparticles (PSNPs) remains a subject of debate. Herein, a series of reaction parameters with different surfactant concentrations, monomer contents, temperatures, and equilibration times were investigated to understand the formation mechanism of PSNPs, which demonstrate a correlation between the properties of PSNPs and the mesostructure of the premix. Cooling the model systems with self-emulsifying nanodroplets (SENDs) in the early reaction stages resulted in the hollow polystyrene spheres (H-PSSs), ruptured PSNPs, and dandelion-like PSNPs, further indicating that the oil nanodroplets are the key sites for the formation of PSNPs.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemical Engineering, Indian Institute of Technology, Jodhpur 342037, India.
Molecular aggregation frequently occurs during material synthesis, cellular processes, and drug delivery systems, often resulting in decreased performance and efficiency. One major reason for such aggregation in an aqueous solution is hydrophobicity. While the basic understanding of the aggregation process of hydrophobic molecules from a thermodynamic standpoint is known, the present literature lacks a connection between the aggregation kinetics and the molecular basis of hydrophobicity.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Mechanical Engineering, Hanyang University ERICA, 55, Hanyangdaehak-ro, Sangnok-gu, Ansan-si 15588, Gyeonggi-do, Republic of Korea.
This study focuses on an equivalent model of Polyvinyl Butyral (PVB) laminated glass to simulate the Head Injury Criterion (HIC) when a pedestrian collides with a TRAM. To simulate the collision behavior that occurs when a pedestrian's head collides with PVB laminated glass, a comparison was made between the results of the widely used PLC model for PVB laminated glass modeling and an actual dynamic head impact test. The material properties of the tempered glass and PVB film used in the PLC and equivalent models were obtained via four-point bending tests and tensile tests, respectively.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)─UMR 6251, F-35000 Rennes, France.
Chloronium (HCl) is an important intermediate of Cl-chemistry in space. The accurate knowledge of its collisional properties allows a better interpretation of the corresponding observations in interstellar clouds and, therefore, a better estimation of its abundance in these environments. While the ro-vibrational spectroscopy of HCl is well-known, the studies of its collisional excitation are rather limited and these are available for the interaction with helium atoms only.
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