The effects of diffusion due to gravity and due to composition gradients on the rate of hydrogen burning in a cooling degenerate dwarf. II - Dependence on initial metallicity and on buffer mass

1986 ◽  
Vol 301 ◽  
pp. 164 ◽  
Author(s):  
I., Jr. Iben ◽  
J. MacDonald
Keyword(s):  
Hydrogen Burning ◽  
Composition Gradients

Water, Water, Here and There

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quark Mass ◽  
Mass Difference ◽  
Baryon Number ◽  
Electroweak Phase Transition ◽  
Hydrogen Burning ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Down Quark ◽  
Unified Theories ◽  
The Stability

Chapter 4 deals with the stability of the proton, hence of hydrogen, and how to reconcile that stability with the baryon number nonconservation (or baryon conservation) needed to establish a matter–antimatter imbalance in the infant universe. Sakharov’s three conditions for establishing a matter–antimatter imbalance are presented. Grand unified theories and experimental searches for proton decay are described. The concept of spontaneous symmetry breaking is introduced in describing the electroweak phase transition in the infant universe. That transition is treated as the potential site for introducing the imbalance between quarks and antiquarks, via either baryogenesis or leptogenesis models. The up–down quark mass difference is presented as essential for providing the stability of hydrogen and of the deuteron, which serves as a crucial stepping stone in stellar hydrogen-burning reactions that generate the energy and elements needed for life. Constraints on quark masses from lattice QCD calculations and violations of chiral symmetry are discussed.

scholarly journals The Chemical Evolution of the Main Component of the Binary System v Sagitarrii

1998 ◽  
Vol 11 (1) ◽  
pp. 390-390
Author(s):  
V. Leushin ◽  
V. Chuvenkov ◽  
L. Snezhko
Keyword(s):  
Chemical Composition ◽  
Binary System ◽  
Core Mass ◽  
Hydrogen Burning ◽  
Convective Mixing ◽  
Mixing Parameters ◽  
Burning Zone ◽  
Nuclear Burning ◽  
Nitrogen Abundance ◽  
Main Component

A model of internal structure and evolution of the peculiar binary system v Sgr is presented. The model corresponds well to the observed chemical composition of the main component atmosphere (10-4 H, 0.844 He, 0.013 C, 0.042 N by mass). It is supposed that about 5 million years ago the main component passed the stage of hydrogen nuclear burning in the shell over the helium core where the helium-carbon reactions took place. Because of convective mixing, the synthesized carbon diffusing into the hydrogen burning zone was catalyzing the reactions of the CN - cycle. This has resulted in anomalies in the chemical composition, particularly high nitrogen abundance in the layer observed now as the atmosphere of the main component since external layers were thrown off during the evolution. Following the calculated results, the quantitative restrictions of temperature and density in the layers and values of mixing parameters are obtained. It is shown that the best agreement with observations exists if the mass of the matter penetrating from the zone of helium-carbon reactions into the helium layer is 0.25 of the helium-carbon core mass. Moreover, the ratio of mass concentration He/C in this matter should equal 2, and the mass share diffusing into the layer of hydrogen burning should be in the range 0.25 - 0.30 of the layer mass.

scholarly journals Study of Stellar Reactions in Explosive Hydrogen Burning with CRIB

2005 ◽  
Vol 758 ◽  
pp. 733-736
Author(s):  
S. Kubono ◽  
T. Teranishi ◽  
M. Notani ◽  
H. Yamaguchi ◽  
A. Saito ◽  
...  
Keyword(s):  
Hydrogen Burning

Fabrication of microscale materials with programmable composition gradients

Lab on a Chip ◽  
2016 ◽  
Vol 16 (7) ◽  
pp. 1234-1242 ◽  
Author(s):  
Cédric Laval ◽  
Anne Bouchaudy ◽  
Jean-Baptiste Salmon
Keyword(s):  
Composition Gradients

Fabrication of microscale materials with programmable composition gradients using the coupling of pervaporation and Quake valves.

scholarly journals Shell and explosive hydrogen burning

2016 ◽  
Vol 52 (4) ◽  
Author(s):  
A. Boeltzig ◽  
C. G. Bruno ◽  
F. Cavanna ◽  
S. Cristallo ◽  
T. Davinson ◽  
...  
Keyword(s):  
Hydrogen Burning

scholarly journals PULSATIONS IN HYDROGEN BURNING LOW-MASS HELIUM WHITE DWARFS

2010 ◽  
Vol 718 (1) ◽  
pp. 441-445 ◽  
Author(s):  
Justin D. R. Steinfadt ◽  
Lars Bildsten ◽  
Phil Arras
Keyword(s):  
White Dwarfs ◽  
Hydrogen Burning ◽  
Low Mass

Emerging Capabilities for the High-Throughput Characterization of Structural Materials

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Daniel B. Miracle ◽  
Mu Li ◽  
Zhaohan Zhang ◽  
Rohan Mishra ◽  
Katharine M. Flores
Keyword(s):  
High Throughput ◽  
Materials Science ◽  
Structural Materials ◽  
Rapid Screening ◽  
Annual Review ◽  
Publication Date ◽  
Synthesis Methods ◽  
Alloy Development ◽  
Composition Gradients ◽  
Future Vision

Structural materials have lagged behind other classes in the use of combinatorial and high-throughput (CHT) methods for rapid screening and alloy development. The dual complexities of composition and microstructure are responsible for this, along with the need to produce bulk-like, defect-free materials libraries. This review evaluates recent progress in CHT evaluations for structural materials. High-throughput computations can augment or replace experiments and accelerate data analysis. New synthesis methods, including additive manufacturing, can rapidly produce composition gradients or arrays of discrete alloys-on-demand in bulk form, and new experimental methods have been validated for nearly all essential structural materials properties. The remaining gaps are CHT measurement of bulk tensile strength, ductility, and melting temperature and production of microstructural libraries. A search strategy designed for structural materials gains efficiency by performing two layers of evaluations before addressing microstructure, and this review closes with a future vision of the autonomous, closed-loop CHT exploration of structural materials. Expected final online publication date for the Annual Review of Materials Science, Volume 51 is August 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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