Laser Powder Bed Fusion (LPBF) of In718 and the Impact of Pre-Heating at 500 and 1000 °C: Operando Study

The morphology of a melt pool has a critical role in laser powder bed fusion (LPBF). Nevertheless, directly characterizing the melt pool during LPBF is incredibly hard. Here, we present the melt pool flow of the entire melt pool in 3D using mesoscopic simulation models. The physical processes occurring within the melt pool are pinpointed. The flow patterns throughout the same are exposed and measured. Moreover, the impact of pre-heating at 500 and 1000 °C has been described. The study findings offer insights into LPBF. The findings presented here are critical for comprehending the LPBF and directing the establishment of improved metrics for process parameters optimization.

MESOSCOPIC SIMULATION OF STRUCTURAL TRANSITIONS IN CYSTEINE-SILVER SOLUTION

Выполнено изучение структурных переходов в цистеин-серебряном растворе в зависимости от изменения концентрации соли - инициатора гелеобразования. Расчеты осуществлялись с использованием скорректированной мезоскопической модели, базирующейся на модели «липких сфер». Построена диаграмма состояний системы в координатах концентрация соли - энергия парного взаимодействия кластеров меркаптида серебра. Показано, что скорректированная модель хорошо воспроизводит все структурные превращения в цистеин-серебряном растворе: золь-гель переход, распад гель сетки и выпадения меркаптида серебра в осадок. The study of structural transitions in a cysteine-silver solution was carried out depending on the change in the concentration of the salt - the initiator of gelation. The calculations are carried out using a modified mesoscopic model based on the «sticky spheres» model. A state diagram was constructed in the coordinates - salt concentration, the pair interaction energy of silver mercaptide clusters. It is shown that the modified model reproduces well all structural transformations in a cysteine-silver solution: sol-gel transition, the disintegration of the gel network, and precipitation of silver mercaptide.

Quantitative Estimation of Cyclotide-Induced Bilayer Membrane Disruption by Lipid Extraction with Mesoscopic Simulation

Cyclotide-induced membrane disruption is studied at the microsecond timescale by Dissipative Particle Dynamics (DPD) to quantitatively estimate a kinetic rate constant for membrane lipid extraction with a “sandwich” interaction model where two bilayer membranes enclose a cyclotide/water compartment. The obtained bioactivity trends for cyclotides Kalata B1, Cycloviolacin O2 and selected mutants with different membrane types are in agreement with experimental findings: For all membranes investigated, Cycloviolacin O2 shows a higher lipid extraction activity than Kalata B1. The presence of cholesterol leads to a decreased cyclotide activity compared to cholesterol-free membranes. Phosphoethanolamine-rich membranes exhibit an increased membrane disruption. A cyclotide’s “hydrophobic patch” surface area is important for its bioactivity. A replacement of or with charged amino acid residues may lead to super-mutants with above-native activity but without simple charge-activity patterns. Cyclotide mixtures show linearly additive bioactivities without significant sub- or over-additive effects.<br>