scholarly journals Demonstration of the effect of stirring on nucleation from experiments on the International Space Station using the ISS-EML facility

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
A. K. Gangopadhyay ◽  
M. E. Sellers ◽  
G. P. Bracker ◽  
D. Holland-Moritz ◽  
D. C. Van Hoesen ◽  
...  

AbstractThe effect of fluid flow on crystal nucleation in supercooled liquids is not well understood. The variable density and temperature gradients in the liquid make it difficult to study this under terrestrial gravity conditions. Nucleation experiments were therefore made in a microgravity environment using the Electromagnetic Levitation Facility on the International Space Station on a bulk glass-forming Zr57Cu15.4Ni12.6Al10Nb5 (Vit106), as well as Cu50Zr50 and the quasicrystal-forming Ti39.5Zr39.5Ni21 liquids. The maximum supercooling temperatures for each alloy were measured as a function of controlled stirring by applying various combinations of radio-frequency positioner and heater voltages to the water-cooled copper coils. The flow patterns were simulated from the known parameters for the coil and the levitated samples. The maximum nucleation temperatures increased systematically with increased fluid flow in the liquids for Vit106, but stayed nearly unchanged for the other two. These results are consistent with the predictions from the Coupled-Flux model for nucleation.

2019 ◽  
Vol 111 ◽  
pp. 01045
Author(s):  
Matei-Razvan Georgescu ◽  
Ilinca Nastase ◽  
Amina Meslem ◽  
Mihnea Sandu ◽  
Florin Bode

An attempt at improving the ventilation solution for the crew quarters aboard the International Space Station requires a thorough understanding of the flow dynamics in a microgravity environment. An experimental study is required in order to validate the numerical models. As part of this process, a small-scale model was proposed for a detailed study of the velocity field. PIV measurements in water offer high quality results and were chosen for the subject. Following certain similitude criteria, an equivalence can be found between the results of these measurements and the real ventilation scenario. This paper describes the development process of this small-scale model as well as its performance in the initial test runs. Details regarding the advantages and weaknesses of this first model are the core of the paper, with the intention of aiding researchers in their design of similar models. The conclusion presents future steps and proposed improvements to the model.


2015 ◽  
Vol 10 (6) ◽  
pp. 1025-1030 ◽  
Author(s):  
Masaki Shirakawa ◽  
◽  
Fumiaki Tanigaki ◽  
Takashi Yamazaki ◽  

The International Space Station (ISS) is a completely closed environment that offers a long-term microgravity environment. It is a unique environment where microbes can fly and attach themselves to devices or humans, especially the exposed parts of the body and head. The ongoing monitoring and analysis of microbes and their movement inside the Japanese Experiment Module (named “Kibo”) of the ISS are intended to study the effects of microbes on humans and prevent health hazards caused by microbes during a long-term space mission. This paper describes the current status and future plan of Japanese microbiological experiments to monitor microbial dynamics in Kibo. It also describes the future prospective and prioritized microbiological research areas based on the “Kibo utilization scenario towards 2020 in the field of life science.” Given the microbial research in space being actively conducted by the USA, NASA and international activities are also reported.


2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Gioia D. Massa ◽  
Nicole F. Dufour ◽  
John A. Carver ◽  
Mary E. Hummerick ◽  
Raymond M. Wheeler ◽  
...  

AbstractThe Veggie vegetable production system was launched to the International Space Station with three sets of test plants for an initial hardware validation test, designated VEG-01. VEG-01A and B featured the crop ‘Outredgeous’ red romaine lettuce, while VEG-01C tested ‘Profusion’ zinnia plants for longer duration growth and flowering characteristics. Irrigation of plants in all three growth studies presented a challenge, with lettuce suffering from inadequate water and zinnia suffering from excess water. Direct plant pillow watering by crew members enabled plant growth, and returned samples from the first crop, VEG-01A, indicated that food safety was acceptable. VEG-01B plants at harvest were split to allow for on-orbit crew consumption as well as science sample return. Direct-watered zinnias suffered fungal growth and other physiological stresses, but two plants survived and these produced numerous flowers. The VEG-01 series allowed a large amount of data on system performance, human factors, procedures, microbiology, and chemistry of space-grown plants to be gathered. Observations from these tests are helping to drive future hardware modifications and provide information on food crop growth and development in a microgravity environment.


Sign in / Sign up

Export Citation Format

Share Document