scholarly journals Nucleation and growth of geological faults

2011 ◽  
Vol 18 (4) ◽  
pp. 529-536 ◽  
Author(s):  
D. Stoyan ◽  
R. Gloaguen
Keyword(s):  
Length Distribution ◽  
Nucleation And Growth ◽  
Resistance To Deformation ◽  
Natural Data ◽  
Spatial Locations ◽  
Descriptive Models ◽  
Fault Length ◽  
Fracture Processes ◽  
Weibull Theory ◽  
Statistical Laws

Abstract. We present a new model of fault nucleation and growth based on the Weibull theory, already widely used in fracture research engineering. We propose that, according to a birth-and-growth process, germs (nuclei) are born at random instants at random spatial locations and then grow with time. This leads to a satisfactory formulation of fault length distribution, different from classical statistical laws. Especially, this formulation reconciles previous analyses of fault datasets displaying power-law and/or exponential behaviors. The Weibull parameters can be statistically estimated in a simple way. We show that the model can be successfully fitted to natural data in Kenya and Ethiopia. In contrast to existing descriptive models developed for geological fault systems, such as fractal approaches, the Weibull theory allows to characterize the strength of the material, i.e. its resistance to deformation. Since this model is very general, we expect that it can be applied in many situations, and for simulations of geological fracture processes. The model is independent of deformation intensity and type and therefore allows a better constraint of the seismic risk in threatened regions.

Fault growth model and the universal fault length distribution

1991 ◽  
Vol 18 (6) ◽  
pp. 1079-1081 ◽  
Author(s):  
Didier Sornette ◽  
Philippe Davy
Keyword(s):  
Growth Model ◽  
Length Distribution ◽  
Fault Growth ◽  
Fault Length

scholarly journals Emergence and maintenance of different sized actin filaments in a common pool of building blocks

2021 ◽  
Author(s):  
Deb Sankar Banerjee ◽  
Shiladitya Banerjee
Keyword(s):  
Growth Inhibition ◽  
Actin Filament ◽  
Actin Filaments ◽  
Length Distribution ◽  
Building Blocks ◽  
Nucleation And Growth ◽  
Actin Binding ◽  
Filament Length ◽  
Growth Promoters ◽  
Spontaneous Nucleation

Actin is one of the key structural components of the eukaryotic cytoskeleton that regulates cellular architecture and mechanical properties. Dynamic regulation of actin filament length and organization is essential for the control of many physiological processes including cell adhesion, motility and division. While previous studies have mostly focused on the mechanisms controlling the mean length of individual actin filaments, it remains poorly understood how distinct actin filament populations in cells maintain different size using the same set of molecular building blocks. Here we develop a theoretical model for the length regulation of multiple actin filaments by nucleation and growth rate modulation by actin binding proteins in a limiting pool of monomers. We first show that spontaneous nucleation of actin filaments naturally leads to heterogeneities in filament length distribution. We then investigate the effects of filament growth inhibition by capping proteins and growth promotion by formin proteins on filament length distribution. We find that filament length heterogeneity can be increased by growth inhibition, whereas growth promoters do not significantly affect length heterogeneities. Interestingly, a competition between filament growth inhibitors and growth promoters can give rise to bimodal filament length distribution as well as a highly heterogeneous length distribution with large statistical dispersion. We quantitatively predict how heterogeneity in actin filament length can be modulated by tuning F-actin nucleation and growth rates in order to create distinct filament subpopulations with different lengths.

A generalized treatment of fault length distribution and magnitude-frequency relationship

1987 ◽  
Vol 31 (1) ◽  
pp. 26-36
Author(s):  
Ludmil Christoskov ◽  
Mariana Eneva ◽  
J. Vaněk
Keyword(s):  
Length Distribution ◽  
Frequency Relationship ◽  
Fault Length

Mechanical Behavior of Sintered Porous Two-Phase Titanium Nanolaminate-Composites at High Temperatures

2009 ◽  
Vol 409 ◽  
pp. 300-303
Author(s):  
Sergiy A. Firstov ◽  
Victor F. Gorban ◽  
Inna I. Ivanova ◽  
Engel P. Pechkovsky
Keyword(s):  
Ceramic Materials ◽  
High Temperature Strength ◽  
Two Phase ◽  
Deformation And Fracture ◽  
Appreciable Increase ◽  
Resistance To Deformation ◽  
Tin Content ◽  
Porous Composites ◽  
Mechanisms Of Deformation ◽  
Fracture Processes

Regularities, features and mechanisms of deformation and fracture processes of new ceramic materials – porous (=3-35 %) two-phase titanium nanolaminate-composites Ti3SiC2/TiC, Ti3AlC2/TiC, Ti4AlN3/TiN (content of TiC or TiN – 5-70 % vol.) at 20-1300 оС are established. Composites are made by reaction sintering. On increase in mechanical properties and resistance to deformation they settle down in the following sequence: Ti3AlC2/TiC–Ti4AlN3/TiN–Ti3SiC2/TiC. In porous nanolaminate-composites containing less than 20 % TiC the increase in porosity  results in decrease in high-temperature strength pl and increase of plasticity . Appreciable increase of strength of porous composites is marked at content TiC>25-30 % (vol.).

scholarly journals Reactive Crystallization Kinetics of K2SO4 from Picromerite-Based MgSO4 and KCl

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1558
Author(s):  
Abad Albis ◽  
Yecid P. Jiménez ◽  
Teófilo A. Graber ◽  
Heike Lorenz
Keyword(s):  
Crystal Growth ◽  
Nucleation Rate ◽  
Length Distribution ◽  
Analytical Techniques ◽  
Nucleation And Growth ◽  
Solution Temperature ◽  
Secondary Nucleation ◽  
Primary Nucleation ◽  
Reactive Crystallization ◽  
Kinetics Of

In this work, the kinetic parameters, the degrees of initial supersaturation (S0) and the profiles of supersaturation (S) were determined for the reactive crystallization of K2SO4 from picromerite (K2SO4.MgSO4.6H2O) and KCl. Different reaction temperatures between 5 and 45 °C were considered, and several process analytical techniques were applied. Along with the solution temperature, the crystal chord length distribution (CLD) was continuously followed by an FBRM probe, images of nucleation and growth events as well as the crystal morphology were captured, and the absorbance of the solution was measured via ATR-FTIR spectroscopy. In addition, the ion concentrations were analyzed. It was found that S0 is inversely proportional to the reactive crystallization temperature in the K+, Mg2+/Cl−, SO42−//H2O system at 25 °C, where S0 promotes nucleation and crystal growth of K2SO4 leading to a bimodal CLD. The CLD was converted to square-weighted chord lengths for each S0 to determine the secondary nucleation rate (B), crystal growth rate (G), and suspension density (MT). By correlation, from primary nucleation rate (Bb) and G with S0, the empirical parameters b = 3.61 and g = 4.61 were obtained as the order of primary nucleation and growth, respectively. B versus G and MT were correlated to the reaction temperature providing the rate constants of B and respective activation energy, E = 69.83 kJ∙mol−1. Finally, a general Equation was derived that describes B with parameters KR = 13,810.8, i = 0.75 and j = 0.71. The K2SO4 crystals produced were of high purity, containing maximal 0.51 wt% Mg impurity, and were received with ~73% yield at 5 °C.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

Electrochemical nucleation and growth of copper on iron and aluminum: A TEM study of industrial copper cementation

1978 ◽  
Vol 36 (1) ◽  
pp. 454-455
Author(s):  
L.E. Murr ◽  
V. Annamalai
Keyword(s):  
Metal Surface ◽  
Copper Deposit ◽  
Nucleation And Growth ◽  
16Th Century ◽  
Electrochemical Reactions ◽  
Mine Shaft ◽  
De Re ◽  
Copper Precipitation ◽  
Electrochemical Nucleation ◽  
Interesting System

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.

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