Nuclear-thermal rocket thrust transient effects on minimum-fuel lunar trajectories

Transient model of oxygen transfer rate in a sequencing batch reactor is derived and solved numerically. The dissolved oxygen response under several conditions is analyzed. Effects of operational parameters and liquid bath height are studied. When with short, intermittent aeration periods, the transient effects on oxygen transfer rate may be substantial and should be taken into considerations. An example considering bioreaction is also given.

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U.S. Economic Uncertainty Shocks and China’s Economic Activities: A Time-Varying Perspective

SAGE Open ◽

10.1177/21582440211032672 ◽

2021 ◽

Vol 11 (3) ◽

pp. 215824402110326

Author(s):

Lin Liu

Keyword(s):

Global Financial Crisis ◽

The United States ◽

Time Varying ◽

Economic Uncertainty ◽

Transient Effects ◽

Economic Activities ◽

Common Shocks ◽

Uncertainty Shocks ◽

Intensive Intervention ◽

The Global Financial Crisis

This paper presents new empirical evidence concerning the time-varying responses of China’s macroeconomy to U.S. economic uncertainty shocks through a novel TVP-VAR model. The results robustly reveal that a rise in U.S. economic uncertainty would exert sizable, persistent, and significant detrimental effects on China’s gross domestic product (GDP), price level, and short-term interest rate during the period when common shocks take place, such as the global financial crisis around 2008, whereas small and transient effects in the tranquil times. Therefore, China should diversify its international linkages and gradually reduce the dependence on the United States into a certain range to shield the domestic economy, as well as improve the independence of monetary policy. Furthermore, to withstand unfavorable external shocks, China should be prudent on greater opening-up and carry out more intensive intervention when common shocks hit the world economy. Finally, investors should be alert to the potential detrimental impact of U.S. economic uncertainty on Chinese assets’ fundamentals.

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Screening for Effects of Inhaled Nanoparticles in Cell Culture Models for Prolonged Exposure

Nanomaterials ◽

10.3390/nano11030606 ◽

2021 ◽

Vol 11 (3) ◽

pp. 606

Author(s):

Claudia Meindl ◽

Kristin Öhlinger ◽

Verena Zrim ◽

Thomas Steinkogler ◽

Eleonore Fröhlich

Keyword(s):

Prolonged Exposure ◽

A549 Cells ◽

Cytokine Release ◽

Transient Effects ◽

Particle Uptake ◽

Particle Accumulation ◽

Low Concentrations ◽

Culture Models ◽

20 Nm ◽

Inhaled Nanoparticles

Respiratory exposure of humans to environmental and therapeutic nanoparticles repeatedly occurs at relatively low concentrations. To identify adverse effects of particle accumulation under realistic conditions, monocultures of Calu-3 and A549 cells and co-cultures of A549 and THP-1 macrophages in the air–liquid interphase culture were exposed repeatedly to 2 µg/cm2 20 nm and 200 nm polystyrene particles with different functionalization. Particle accumulation, transepithelial electrical resistance, dextran (3–70 kDa) uptake and proinflammatory cytokine secretion were determined over 28 days. Calu-3 cells showed constant particle uptake without any change in barrier function and cytokine release. A549 cells preferentially ingested amino- and not-functionalized particles combined with decreased endocytosis. Cytokine release was transiently increased upon exposure to all particles. Carboxyl-functionalized demonstrated higher uptake and higher cytokine release than the other particles in the A549/THP-1 co-cultures. The evaluated respiratory cells and co-cultures ingested different amounts and types of particles and caused small (partly transient) effects. The data suggest that the healthy cells can adapt to low doses of non-cytotoxic particles.

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Effects of slide-to-roll ratio and varying velocity on the lubrication performance of grease at low speed

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650121993362 ◽

2021 ◽

pp. 135065012199336

Author(s):

Yiming Han ◽

Jing Wang ◽

Xuyang Jin ◽

Shanshan Wang ◽

Rui Zhang

Keyword(s):

Steady State ◽

Critical Speed ◽

Industrial Applications ◽

Transient Effects ◽

Disintegration Time ◽

Low Speed ◽

Existence Time ◽

Pure Rolling ◽

Lubrication Performance ◽

Long Time

Under steady-state pure rolling conditions with low speed, the thickener fiber agglomerations can be maintained for a long time, generating a beneficial thicker film thickness. However, in industrial applications, motions with sliding or transient effects are very common for gears, rolling-element bearings or even chain drives, evaluation of the grease performance under such conditions is vital for determining the lubrication mechanism and designing new greases. In this project, optical interferometry experiments were carried out on a ball-disk test rig to study the disintegration time of the grease thickener agglomerations with the increase of the slide-to-roll ratio under steady-state and reciprocation motions. Under steady-state conditions, the thickener fiber agglomeration can exist for a while and the time becomes shorter with the increase of the slide-to-roll ratio above the critical speed. Below the critical speed, the thickener fiber can exist in the contact in the form of a quite thick film for a very long time under pure rolling conditions but that time is decreased with the increase of the slide-to-roll ratio. The introduction of the transient effect can further reduce the existence time of the thickener.

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