EFFECTS OF DYNAMIC VS. STATIC COMPACTION ON THE SINTERABILITY OF ALUMINA POWDERS**Submitted by Y. Horie

Kim, K.Y.; Palmour, Hayne; Batchelor, A. D.; Kanda, H.; Akaishi, Minoru; Fukunaga, Osamu

doi:10.1016/b978-0-444-86904-3.50103-2

Cited by 3 publications

(4 citation statements)

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“…However, the explosive compacted powders, after sintering, reached values of density and microhardness comparables to the ones of commercial alumina. This enhanced sinterability, due to the increase of lattice distortion, is in accordance with what has been referred by several authors [4,5].…”

Section: Sintering Experimentssupporting

confidence: 92%

“…Kim et al [5] reported that the significant differences in the initial density found for alumina specimens compacted by different ways, have effects only in the early stages of the densification process. However, in the present study, those consequences are still perceptible in the final density and consequently in the hardness.…”

Section: Sintering Experimentsmentioning

confidence: 99%

“…In fact, being the sintering largely controlled by the morphology and microstructure of the particles, it is expected that variations in those parameters induce significant differences in the sinterability of the powders/compacts. Shock processing of powders, usually described as shock activation, is thought to be capable of such variations due to particle comminution and increase of lattice distortion [4,5].…”

Section: Introductionmentioning

confidence: 99%

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Shock activation of α-alumina from calcinated Al-rich sludge

Farinha¹,

Ribeiro²,

Mendes³

et al. 2009

Ceramics International

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Enormous quantities of Al-sludge from aluminum surface treatments are yearly generated all over the world. Despite of being known as important supplier of alumina, the Al-sludge also have some other components that need to be removed. Calcination has revealed to be an inevitable treatment to achieve such objective. It was also found that conventional densification processes are not efficient for this kind of powders and, to overcome that difficulty, a dynamic compaction approach, using detonation generated shock waves have been followed. The calcinated powders compacted by this way have shown up values of density and hardness, after sintering, comparable to the ones of commercial alumina processed by the conventional methods.

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Section: Sintering Experimentssupporting

confidence: 92%

Section: Sintering Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Shock activation of α-alumina from calcinated Al-rich sludge

Farinha¹,

Ribeiro²,

Mendes³

et al. 2009

Ceramics International

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“…Inclusion of these interactions extends the present one dimensional two-layer Potts model into higher dimensions and one expects even richer physics [16]. Furthermore, epigenetic memory is maintained by a closed network coupling regulations at different levels including gene expression, epigenetic modification, chromatin remodeling, etc [34,35], and requires an integrated treatment in the future.…”

mentioning

confidence: 99%

Statistical Mechanics Model for the Dynamics of Collective Epigenetic Histone Modification

et al. 2014

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Epigenetic histone modifications play an important role in the maintenance of different cell phenotypes. The exact molecular mechanism for inheritance of the modification patterns over cell generations remains elusive. We construct a Potts-type model based on experimentally observed nearest-neighbor enzyme lateral interactions and nucleosome covalent modification state biased enzyme recruitment. The model can lead to effective nonlocal interactions among nucleosomes suggested in previous theoretical studies, and epigenetic memory is robustly inheritable against stochastic cellular processes.PACS numbers: 82.39. Rt, 87.17.Aa, 87.16.Yc, 87.16.A Nucleosomes are basic organizational units of chromatin in eukaryotic cells. A typical nucleosome has approximately 147 base pairs wrapped around a histone octamer and are interconnected by linker DNA of varying length (see Fig. 1) [1,2]. Covalent modifications of several amino acid residues on the histone core can lead to either active or repressive gene expression activities [3]. A dynamic equilibrium in the nucleosome modification state is attained due to a 'tug-of-war' between the associated covalent mark addition and removal enzymes [4]. The system may show a bistable behavior due to coexistence of repressive and active epigenetic states for different copies of a gene within the same cell [5].Experiments suggest that at least some of the nucleosome covalent patterns can be transmitted over a number of generations [1]. Although the actual mechanism for this epigenetic memory is unclear, a simple rule-based model by Dodd et al. [5] shows that robust bistability requires cooperative effects beyond neighboring nucleosomes, which they suggest is due to compact chromatin structures. Subsequent theoretical studies on yeast chromatin silencing [6], mouse stem cell differentiation [7], and plant flowering regulation [8] also conclude that this nonlocal cooperativity is necessary for generating stable epigenetic memory.In recent years molecular details on nucleosome covalent modification dynamics have been extensively studied. Measurements show that the typical residence time of a modification enzyme on chromatin is within sub-seconds to a few minutes [4]. Experimental observations also suggest that a modified nucleosome may have higher binding affinity for the corresponding enzymes [3,[9][10][11]. Another interesting observation is that a nucleosome bound modification enzyme complex laterally interacts with another bound to neighboring nucleosomes [10,12,13].Although the functional consequences of these interactions on epigenetic dynamics are unclear, recent work suggests that increased [14,15].In this work we construct a theoretical model aiming to bridge the gap between detailed molecular events occurring at the sub-second time scale, and the long-time scale epigenetic change dynamics that is typically in days or longer. To be specific we focus on lysine 4 (active) and lysine 9 (repressive) methylation on histone H3, although we expect the mechanism discussed here can be...

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Mid-Life Turning Points

Horie

2022

My Journey With Shock Waves

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EFFECTS OF DYNAMIC VS. STATIC COMPACTION ON THE SINTERABILITY OF ALUMINA POWDERS**Submitted by Y. Horie

Cited by 3 publications

References 1 publication

Shock activation of α-alumina from calcinated Al-rich sludge

Shock activation of α-alumina from calcinated Al-rich sludge

Statistical Mechanics Model for the Dynamics of Collective Epigenetic Histone Modification

Mid-Life Turning Points

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