Atomistic Simulation of Pipe Diffusion in AlCu Alloys

2006 ◽  
Vol 249 ◽  
pp. 47-54 ◽  
Author(s):  
E. Jannot ◽  
Volker Mohles ◽  
Günter Gottstein ◽  
B. Thijsse
Keyword(s):  
Activation Energy ◽  
Atomistic Simulation ◽  
Formation Energy ◽  
Activation Energies ◽  
Solute Diffusion ◽  
Atomistic Simulations ◽  
Pipe Diffusion ◽  
The Core ◽  
Very High ◽  
Insight Into

Activation energies for solute diffusion along dislocations are difficult to measure experimentally. The aim of this work is to provide insight into pipe diffusion with the help of atomistic simulations. The distribution of vacancy formation energy and the activation energy for copper migration are determined in the core of an edge dislocation in aluminum. The Dimer method is used to find activation energies for vacancy migration. The activated region around the dislocation where a very high diffusivity is observed and the activation energy for copper diffusion associated with this region are interpreted with regard to the contribution of the dislocation and the contribution of the alloying.

scholarly journals Two interacting PPR proteins are major Arabidopsis editing factors in plastid and mitochondria

2017 ◽  
Vol 114 (33) ◽  
pp. 8877-8882 ◽  
Author(s):  
Damien Guillaumot ◽  
Mauricio Lopez-Obando ◽  
Kevin Baudry ◽  
Alexandra Avon ◽  
Guillem Rigaill ◽  
...  
Keyword(s):  
Affinity Purification ◽  
Rna Modification ◽  
Chloroplast Biogenesis ◽  
Pentatricopeptide Repeat ◽  
The Core ◽  
Ppr Protein ◽  
Ppr Proteins ◽  
P Type ◽  
Very High ◽  
Insight Into

RNA editing is converting hundreds of cytosines into uridines during organelle gene expression of land plants. The pentatricopeptide repeat (PPR) proteins are at the core of this posttranscriptional RNA modification. Even if a PPR protein defines the editing site, a DYW domain of the same or another PPR protein is believed to catalyze the deamination. To give insight into the organelle RNA editosome, we performed tandem affinity purification of the plastidial CHLOROPLAST BIOGENESIS 19 (CLB19) PPR editing factor. Two PPR proteins, dually targeted to mitochondria and chloroplasts, were identified as potential partners of CLB19. These two proteins, a P-type PPR and a member of a small PPR-DYW subfamily, were shown to interact in yeast. Insertional mutations resulted in embryo lethality that could be rescued by embryo-specific complementation. A transcriptome analysis of these complemented plants showed major editing defects in both organelles with a very high PPR type specificity, indicating that the two proteins are core members of E+-type PPR editosomes.

Will Love Tear Us Apart: Adapting the Lyrical to the Ludic

CounterText ◽  
2016 ◽  
Vol 2 (2) ◽  
pp. 217-235
Author(s):  
Gordon Calleja
Keyword(s):  
Design Process ◽  
Game Design ◽  
Digital Games ◽  
Design Decisions ◽  
The Core ◽  
Lyrical Poetry ◽  
Insight Into ◽  
Made In

This paper gives an insight into the design process of a game adaptation of Joy Division's Love Will Tear Us Apart (1980). It outlines the challenges faced in attempting to reconcile the diverging qualities of lyrical poetry and digital games. In so doing, the paper examines the design decisions made in every segment of the game with a particular focus on the tension between the core concerns of the lyrical work being adapted and established tenets of game design.

Force in Nature

2020 ◽  
pp. 146-160
Author(s):  
David Carus
Keyword(s):  
Natural Science ◽  
The Body ◽  
The Core ◽  
Thing In Itself ◽  
The Will ◽  
Insight Into

This chapter explores Schopenhauer’s concept of force, which lies at the root of his philosophy. It is force in nature and thus in natural science that is inexplicable and grabs Schopenhauer’s attention. To answer the question of what this inexplicable term is at the root of all causation, Schopenhauer looks to the will within us. Through will, he maintains that we gain immediate insight into forces in nature and hence into the thing in itself at the core of everything and all things. Will is thus Schopenhauer’s attempt to answer the question of the essence of appearance. Yet will, as it turns out, cannot be known immediately as it is subject to time, and the acts of will, which we experience within us, do not correlate immediately with the actions of the body (as Schopenhauer had originally postulated). Hence, the acts of will do not lead to an explanation of force, which is at the root of causation in nature. Schopenhauer sets out to explain what is at the root of all appearances, derived from the question of an original cause, or as Schopenhauer states “the cause of causation,” but cannot determine this essence other than by stating that it is will; a will, however, that cannot be immediately known.

scholarly journals High-Temperature Deformation of Naturally Aged 7010 Aluminum Alloy

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 581
Author(s):  
Abdulhakim A. Almajid
Keyword(s):  
Activation Energy ◽  
Aluminum Alloy ◽  
High Temperature ◽  
Threshold Stress ◽  
Activation Energies ◽  
Temperature Deformation ◽  
High Temperature Range ◽  
Temperature Range ◽  
True Activation Energy ◽  
Two Temperatures

This study is focused on the deformation mechanism and behavior of naturally aged 7010 aluminum alloy at elevated temperatures. The specimens were naturally aged for 60 days to reach a saturated hardness state. High-temperature tensile tests for the naturally aged sample were conducted at different temperatures of 573, 623, 673, and 723 K at various strain rates ranging from 5 × 10−5 to 10−2 s−1. The dependency of stress on the strain rate showed a stress exponent, n, of ~6.5 for the low two temperatures and ~4.5 for the high two temperatures. The apparent activation energies of 290 and 165 kJ/mol are observed at the low, and high-temperature range, respectively. These values of activation energies are greater than those of solute/solvent self-diffusion. The stress exponents, n, and activation energy observed are rather high and this indicates the presence of threshold stress. This behavior occurred as a result of the dislocation interaction with the second phase particles that are existed in the alloy at the testing temperatures. The threshold stress decreases in an exponential manner as temperature increases. The true activation energy was computed by incorporating the threshold stress in the power-law relation between the stress and the strain. The magnitude of the true activation energy, Qt dropped to 234 and 102 kJ/mol at the low and high-temperature range, respectively. These values are close to that of diffusion of Zinc in Aluminum and diffusion of Magnesium in Aluminum, respectively. The Zener–Hollomon parameter for the alloy was developed as a function of effective stress. The data in each region (low and high-temperature region) coalescence in a segment line in each region.

scholarly journals Effect of CaO on catalytic combustion of semi-coke

2021 ◽  
Vol 10 (1) ◽  
pp. 011-020
Author(s):  
Luyao Kou ◽  
Junjing Tang ◽  
Tu Hu ◽  
Baocheng Zhou ◽  
Li Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Combustion Rate ◽  
Activation Energies ◽  
Combustion Reaction ◽  
Tg Analysis ◽  
Conversion Rates ◽  
Apparent Activation Energies ◽  
Ozawa Integral Method ◽  
Addition Amount

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

scholarly journals Temporal hierarchy of intrinsic neural timescales converges with spatial core-periphery organization

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mehrshad Golesorkhi ◽  
Javier Gomez-Pilar ◽  
Shankar Tumati ◽  
Maia Fraser ◽  
Georg Northoff
Keyword(s):  
Time Window ◽  
Human Cortex ◽  
The Core ◽  
Novel Variant ◽  
Open Issue ◽  
Task Differences ◽  
Spatial Hierarchy ◽  
Fundamental Insight ◽  
Insight Into ◽  
And Task

AbstractThe human cortex exhibits intrinsic neural timescales that shape a temporal hierarchy. Whether this temporal hierarchy follows the spatial hierarchy of its topography, namely the core-periphery organization, remains an open issue. Using magnetoencephalography data, we investigate intrinsic neural timescales during rest and task states; we measure the autocorrelation window in short (ACW-50) and, introducing a novel variant, long (ACW-0) windows. We demonstrate longer ACW-50 and ACW-0 in networks located at the core compared to those at the periphery with rest and task states showing a high ACW correlation. Calculating rest-task differences, i.e., subtracting the shared core-periphery organization, reveals task-specific ACW changes in distinct networks. Finally, employing kernel density estimation, machine learning, and simulation, we demonstrate that ACW-0 exhibits better prediction in classifying a region’s time window as core or periphery. Overall, our findings provide fundamental insight into how the human cortex’s temporal hierarchy converges with its spatial core-periphery hierarchy.

scholarly journals The Effect of α-Al(MnCr)Si Dispersoids on Activation Energy and Workability of Al-Mg-Si-Cu Alloys during Hot Deformation

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiaoguo Wang ◽  
Jian Qin ◽  
Hiromi Nagaumi ◽  
Ruirui Wu ◽  
Qiushu Li
Keyword(s):  
Activation Energy ◽  
Aluminum Alloys ◽  
Constitutive Equation ◽  
Hot Deformation ◽  
Flow Instability ◽  
Void Formation ◽  
Activation Energies ◽  
Compression Tests ◽  
Softening Mechanism ◽  
Dynamic Softening

The hot deformation behaviors of homogenized direct-chill (DC) casting 6061 aluminum alloys and Mn/Cr-containing aluminum alloys denoted as WQ1 were studied systematically by uniaxial compression tests at various deformation temperatures and strain rates. Hot deformation behavior of WQ1 alloy was remarkably changed compared to that of 6061 alloy with the presence of α-Al(MnCr)Si dispersoids. The hyperbolic-sine constitutive equation was employed to determine the materials constants and activation energies of both studied alloys. The evolution of the activation energies of two alloys was investigated on a revised Sellars’ constitutive equation. The processing maps and activation energy maps of both alloys were also constructed to reveal deformation stable domains and optimize deformation parameters, respectively. Under the influence of α dispersoids, WQ1 alloy presented a higher activation energy, around 40 kJ/mol greater than 6061 alloy’s at the same deformation conditions. Dynamic recrystallization (DRX) is main dynamic softening mechanism in safe processing domain of 6061 alloy, while dynamic recovery (DRV) was main dynamic softening mechanism in WQ1 alloy due to pinning effect of α-Al(MnCr)Si dispersoids. α dispersoids can not only resist DRX but also increase power required for deformation of WQ1 alloy. The microstructure analysis revealed that the flow instability was attributed to the void formation and intermetallic cracking during hot deformation of both alloys.

New experiments on the relationship between light-induced defects and photoconductivity degradation

2001 ◽  
Vol 664 ◽  
Author(s):  
Stephan Heck ◽  
Howard M. Branz
Keyword(s):  
Activation Energy ◽  
Defect Density ◽  
Activation Energies ◽  
Dangling Bond ◽  
Fast Recovery ◽  
Slow Recovery ◽  
Degradation Model ◽  
Induced Defects ◽  
The Relationship ◽  
Hydrogenated Amorphous

ABSTRACTWe report experimental results that help settle apparent inconsistencies in earlier work on photoconductivity and light-induced defects in hydrogenated amorphous silicon (a-Si:H) and point toward a new understanding of this subject. After observing that light-induced photoconductivity degradation anneals out at much lower T than the light-induced increase in deep defect density, Han and Fritzsche[1] suggested that two kinds of defects are created during illumination of a-Si:H. In this view, one kind of defect degrades the photoconductivity and the other increases defect sub-bandgap optical absorption. However, the light-induced degradation model of Stutzmann et al.[2] assumes that photoconductivity is inversely proportional to the dangling-bond defect density. We observe two kinds of defects that are distinguished by their annealing activation energies, but because their densities remain in strict linear proportion during their creation, the two kinds of defects cannot be completely independent.In our measurements of photoconductivity and defect absorption (constant photocurrent method) during 25°C light soaking and during a series of isochronal anneals between 25 < T < 190°C, we find that the absorption measured with E ≤1.1 eV, first increases during annealing, then exhibits the usual absorption decrease found for deeper defects. The maximum in this absorption at E ≤1.1eV occurs simultaneously with a transition from fast to slow recovery of photoconductivity. The absorption for E ≤1.1eV shows two distinct annealing activation energies: the signal rises with about 0.87 eV and falls with about 1.15 eV. The 0.87 eV activation energy roughly equals the activation energy for the dominant, fast, recovery of photoconductivity. The 1.15 eV activation energy roughly equals the single activation energy for annealing of the light-induced dangling bond absorption.

Insight into the formation of a continuous sheath structure for the PS phase in tri-continuous PVDF/PS/HDPE blends

RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 439-447 ◽  
Author(s):  
Rui Dou ◽  
Shuanglin Li ◽  
Yan Shao ◽  
Bo Yin ◽  
Mingbo Yang
Keyword(s):  
Ternary Blends ◽  
Continuous Structure ◽  
High Level ◽  
Very High ◽  
Insight Into ◽  
Sheath Structure

A hierarchical tri-continuous structure is formed and controlled in PVDF/PS/HDPE ternary blends. A very high level of PS continuity, about 80%, is achieved only with a PS volume composition as low as 11 vol%.

Atomistic Simulation of Volumetric Properties of Epoxy Networks: Effect of Monomer Length

Soft Matter ◽  
2021 ◽  
Author(s):  
Ketan S. Khare ◽  
Cameron F Abrams
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Atomistic Simulation ◽  
Volumetric Properties ◽  
Epoxy Networks ◽  
Design Requirements ◽  
Dynamics Simulations ◽  
Insight Into

Properties of epoxy thermosets can be varied broadly to suit design requirements by altering the chemistry of the component agents. Atomistically-detailed molecular dynamics simulations are well-suited for molecular insight into...

Sign in / Sign up

Export Citation Format

Share Document