A Comprehensive Overview of Atmospheric and Spaceflight Operation| Chapter 2 | Physical Science: New Insights and Developments Vol. 2

 

The limit of the atmosphere and the beginning of space are considered to be at 100 km altitude. Microgravity is the term used to characterise the very low acceleration level encountered inside a spacecraft in LEO (Low Earth Orbit). The study aims to monitor atmospheric operations and their applications. Chemical composition in the lower layers: 78% of nitrogen, 21% of oxygen, 1% of argon, and < 0.1% others and then a very small amount of other molecules, mainly water vapour and carbon dioxide, are present, which are in fact greenhouse gases, so they are important although they are small in quantity in the atmosphere compared to the other components. In terms of temperature evolution towards the atmosphere, at the level of the ground, with a temperature of 288 K, or 15°C. As one goes up in the mesosphere, about 50 km altitude, the temperature decreases again, and then above 80-90 km altitude it starts to increase again, because of the ionisation of the oxygen, mainly, and somewhat nitrogen atoms in the so-called thermosphere. Microgravity: these are the conditions that one can have in free fall. If someone has pure free fall, they are going to have zero-g or weightlessness, but in fact, there are always perturbing forces. The Hohmann transfer is a special kind of transfer from one circular orbit to another circular orbit. First of all, manoeuvring in orbit is basically <i>ΔV vectorial</i> that, if applied at some point in the orbit of a satellite or spacecraft that one will change the orbit. Here is an example of an initial circular orbit, and if velocity is added in the direction of the circular velocity. At some point,  <i>ΔV</i>, if added, it will change the orbit to an elliptical orbit of high energy. Basically, energy was added to the orbit, kinetic energy was also added, so a larger value of the semi-major axis can be obtained instead of the radius <i>r</i> of the initial circular orbit. An elliptical orbit appears, which has a semi-major axis larger than the radius of the initial circular orbit. Now, only instantaneous <i>ΔV</i> will be considered. This is the simplification. Most of the time, the initial conditions are a spacecraft on the ground, called the chaser, which is active and another spacecraft in orbit, the target, which is passive.

 

Author(s) DetailsP.Sateesh
Department of Physics, St. Peter’s Engineering College, India.

 

A.Rajesh
Department of Physics, St. Peter’s Engineering College, India.

 

Ch.Chakrapani
Department of BS&H, Seshadri Rao Gudlavalleru Engineering College, India.

 

P.Siva Kumar
Department of Physics, Kaveri University, Gowraram, India.

 

Y.Durga Sravanthi
Department of Chemistry, St. Peter’s Engineering College, India.

 

Masma Shaik
Department of Chemistry, St. Peter’s Engineering College, India.

 

Hemanth Kumar Narsetti
Department of Physics, St. Peter’s Engineering College, India.

 

M.Rajesh
Department of Physics, St. Peter’s Engineering College, India.

 

T.Ram Prasad
Department of Physics, St. Peter’s Engineering College, India.

 

K.Gopinath
Department of Chemistry, St. Peter’s Engineering College, India.

 

Please see the book here:- https://doi.org/10.9734/bpi/psniad/v2/5931

 

Numerical Study on the Effect of Convection on Grain Growth Structure in Metallic Systems | Chapter 9 | Proceedings of the 8th International Conference on Solidification and Gravity

 The effect of convection within the droplet during the levitation experiment on the grain structure was investigated using phase-field simulation considering convection. This study aims to distinguish the effects of convection and heterogeneous nucleation on the grain structure. In binary alloy systems, convection generates a strong solute gradient near the solid-liquid interface, leading to faster solid growth.  The effect of flow velocity on the degree of grain deformation was investigated based on elliptical fitting and aspect ratio, and it was found that the shape of grown grains tends to deform with an increase in convection velocity. Under levitation experimental conditions, the aspect ratio decreased up to 0.80 times compared to the no-flow case. Small vortices are generated for the further large velocity, creating the local concentration gradient, thus resulting in the short-wavelength grain interface. In the solidification of pure metals based on heat transport, the effect of convection on grain shape was relatively small compared to the case of binary alloys because of the large thermal diffusion.

 

Author (s) Details

 

Kohei Tanimoto
Graduate School of Integrative Science and Engineering, Tokyo City University, Tokyo 158-8557, Japan.

Nagano Hideaki
Department of Mechanical Systems Engineering, Tokyo City University, Tokyo 158-8557, Japan.

Kenjiro Shimano
Department of Mechanical Systems Engineering, Tokyo City University, Tokyo 158-8557, Japan.

Suguru Shiratori
Department of Mechanical Systems Engineering, Tokyo City University, Tokyo 158-8557, Japan.

 

Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-49473-95-9/CH9

Comparison of Image Analysis Techniques for the Determination of the Influence of Melt Flow on the Solidification Microstructure of Technical Aluminum Alloys | Chapter 5 | | Proceedings of the 8th International Conference on Solidification and Gravity

This work aims to contribute to the improvement of automated analysis of 2D microstructures in technical aluminum alloys by evaluating the effectiveness of various microstructural image analysis methods: Traditional analysis techniques for 2D images and cutting-edge computer vision deep learning-based methods (Mask Region-based Convolutional Neural Networks or Mask R-CNN [1], a model used to detect the position and exact shape of objects) are compared for detecting, classifying, and quantifying microstructural features in technical iron containing aluminum alloys. Determining that deep learning-based methods lead to comparable or better results would allow for such models to be used for analysis of the chosen microstructural features. This could improve detection accuracy and speed, as well as measurement reproducibility.

The focus is on detecting and characterizing Fe-containing intermetallic phases that precipitate during solidification, with the aim of examining the effects of increased iron content on the microstructure of these alloys. Therefore, the microstructure of directionally solidified hypoeutectic AlSi6Cu4Fe1 and hypereutectic AlSi6Cu4Fe2 alloys is analyzed with regards to area fraction and size of the intermetallic precipitates within two distinct sample processing zones: the first half of the samples was solidified under diffusive mass transport conditions and the second under forced convective conditions, both in microgravity. This dual approach allows for the evaluation of the impact of convection on the microstructure of aluminum alloys with elevated iron content.

 

Author (s) Details

 

Golo Zimmermann
RWTH Aachen University, Foundry Institute, Intzestraße 5, 52072 Aachen, Germany.

 

Sonja Steinbach
Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.

Laszlo Sturz
ACCESS e.V., Intzestraße 5, 52072 Aachen, Germany.

 

Alexandre Viardin
ACCESS e.V., Intzestraße 5, 52072 Aachen, Germany.

 

Angelos Theofilatos
ACCESS e.V., Intzestraße 5, 52072 Aachen, Germany.

 

Florian Kargl
RWTH Aachen University, Foundry Institute, Intzestraße 5, 52072 Aachen, Germany and Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.

 

Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-49473-95-9/CH5

Effect of Solidification Parameters on the Amount of Eutectic and Secondary Arm Spacing of Al–7wt%Si Alloy Solidified under Microgravity: An Experimental Analysis | Chapter 4 | Effect of Microgravity and Magnetic Steering on the Melt Flow and the Microstructure of Solidified Alloys

This chapter highlights the effect of G and v on the secondary dendrite arm spacing (SDAS) in purely diffusion circumstances, analysed the thermal data of the experiments in detail, and take into account the macrosegregation caused by the diffusion of Si from the initial mushy zone during the homogenization step of experiments. During the solidification of hypoeutectic alloy (like Al-7% Si), density difference develops in the melt generated by concentration and temperature difference. On Earth, as an effect of this density difference, the melt can flow due to gravity affecting the solidified microstructure. The developing meso- and micro-structures are also significantly affected by the melt flow occurring during the solidification processes in different casting technologies. This melt flow can be eliminated in a microgravity environment, which then makes it possible to examine the solidification process under conditions of pure diffusion. In the Materials Science Lab (MSL) on board the International Space Station (ISS), four solidification experiments were conducted on grain refined and non-grain refined Al-7wt% Si alloy to investigate the effects of the solidification parameters  (solid/liquid front velocity v, temperature gradient G) on the dendritic microstructures and the grain structure. A detailed analysis of the grain structure was conducted in a few previous articles. The macrosegregation was calculated by the Finite Different Method. Because the steady-state solidification conditions were never reached, the solidification process was characterized by the average front velocity and temperature gradient. It is shown that steady-state solidification conditions are never reached. At a given sample position, the velocity of the solid/liquid S/L) and the eutectic/liquid (E/L) fronts and the temperature gradient at the two fronts are different. Then, the solidification process can be characterized by the average front velocity and average temperature gradient.

Author(s) Details:

András Roósz,
HUN REN- University of Miskolc, Materials Science Research Group, Hungary and Institute of Physical Metallurgy, Metal Forming, and Nanotechnology, University of Miskolc, Hungary.

Arnold Rónaföldi,
HUN REN- University of Miskolc, Materials Science Research Group, Hungary and Institute of Physical Metallurgy, Metal Forming, and Nanotechnology, University of Miskolc, Hungary.

Yuze Li,
School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an, 710100, China.

Nathalie Mangelinck-Noël,
Aix Marseille University, Université de Toulon, CNRS, IM2NP, 13013 Marseille, France.

Gerherd Zimmermann,
ACCESS e.V., Intzestrasse 5, Aachen, Germany.

Henri Nguyen-Thi,
Aix Marseille University, Université de Toulon, CNRS, IM2NP, 13013 Marseille, France.

Mária Svéda,
HUN REN- University of Miskolc, Materials Science Research Group, Hungary.

Zsolt Veres,
HUN REN- University of Miskolc, Materials Science Research Group, Hungary and Institute of Physical Metallurgy, Metal Forming, and Nanotechnology, University of Miskolc, Hungary.

Please see the link here: https://stm.bookpi.org/EMMSMFMSA/article/view/13079

Microgravity, Bone Homeostasis, and Insulin-Like Growth Factor-1: A Review | Chapter 01 | Recent Developments in Medicine and Medical Research Vol. 16

 Despite their devotion to high-impact exercise training regimens and meals high in minerals, potassium, calcium, and vitamin D, astronauts are at danger of losing 1.0-1.5 percent of their bone mass for every month they stay in space, all of which are designed to preserve the skeletal system. The anatomy and function of osteoblasts, osteocytes, osteoclasts, and their mesenchymal and hematopoietic stem cell origins are discussed in this chapter, as well as how exposure to microgravity or simulated microgravity affects them. It goes through the importance of insulin-like growth factor-1 (IGF-1) and its receptor insulin-like growth factor-1 receptor (GF1-R) in maintaining bone homeostasis, as well as how microgravity impacts the activity of these growth factors in bone cells. Finally, it discusses the potential of TRAIL, syncytin-A, sclerostin inhibitors, and recombinant IGF-1 (rIGF-1) as bone-saving therapy for astronauts in space and during moon colonisation. IGF-1 and its receptor, IGF1R, are important at all stages of bone development, encouraging both radial and linear bone growth.

 
Author(S) Details

John Kelly Smith
Departments of Academic Affairs and Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, P.O. Box 70300, Johnson City, TN 37614, USA.

View Book:- https://stm.bookpi.org/RDMMR-V16/article/view/5230

Lunar Diastolic Hypertension of Neil Armstrong | Chapter 9 | Highlights on Medicine and Medical Science Vol. 12

 Because of its high iron concentration, which can be picked up by a magnet, lunar dust has been discovered to be very poisonous. It's a special type of regolith on the moon, made up mostly of impact-created glass with nano-sized metallic iron particles. There is a link between airborne particulate matter and cardiovascular illness and mortality, according to epidemiological studies. In instrumented large animals exposed to concentrated ambient particles, there is evidence of immediate cardiovascular consequences. The challenges encountered on Earth with ever rising urban pollution and exposure to automotive brake iron packed dust are exemplified by Neil Armstrong's solitary spacewalk, which resulted in heart failure and inhalation of fatal lunar dust.

Author (S) Details

William J. Rowe
Medical University of Ohio, Toledo, USA.

View Book :- https://stm.bookpi.org/HMMS-V12/article/view/2700