Kirkendall Effect during Grain Boundary Interdiffusion in Polycrystalline Thin Films

2012 ◽  
Vol 323-325 ◽  
pp. 49-54
Author(s):  
Leonid Klinger ◽  
Eugen Rabkin
Keyword(s):  
Kirkendall Effect ◽  
Thin Metal Film ◽  
Stress Evolution ◽  
Initial Value ◽  
Compressive Stresses ◽  
Polycrystalline Thin Films ◽  
Interdiffusion Process ◽  
Inert Substrate ◽  
The Difference ◽  
Kinetics Of

We consider the kinetics of chemical interdiffusion along the grain boundaries in stressed thin metal film attached to inert substrate. We show that the kinetics of stress relaxation in the film can be either accelerated or slowed down if compared with the same kinetics in a single-component film, depending on the difference of intrinsic GB diffusion coefficients of the two components. In the case of faster matrix atoms the tensile stress in the film significantly increases beyond its initial value at the beginning of interdiffusion process, while in the case of faster diffuser atoms the compressive stresses develop in the film at the intermediate stages of stress evolution.

Plasticity in Polycrystalline Thin Films: a 2D Dislocation Dynamics Approach

2003 ◽  
Vol 779 ◽  
Author(s):  
Lucia Nicola ◽  
Erik Van der Giessen ◽  
Alan Needleman
Keyword(s):  
Thin Films ◽  
Dislocation Dynamics ◽  
Stress Evolution ◽  
Polycrystalline Thin Films ◽  
Discrete Dislocation ◽  
Dislocation Plasticity ◽  
Strain Formulation ◽  
The Difference ◽  
Film Substrate ◽  
Edge Dislocations

AbstractThermal stress evolution in polycrystalline thin films is analyzed using discrete dislocation plasticity. Stress develops in the film during cooling from a stress-free configuration due to the difference in thermal expansion coefficient between the film and its substrate. A plane strain formulation with only edge dislocations is used and each grain of the polycrystal has a specified set of slip systems. The film–substrate interface and the grain boundaries are impenetrable for the dislocations. Results are presented for two film thicknesses, with higher hardening seen for the thinner films.

The effect of composition of cobalt-molybdenum catalysts on their surface acidity and isomerisation activity

1980 ◽  
Vol 45 (3) ◽  
pp. 697-702 ◽  
Author(s):  
Vlastimil Vyskočil ◽  
Miroslav Zdražil
Keyword(s):  
Chromatographic Method ◽  
Surface Acidity ◽  
Parallel Reaction ◽  
Molybdenum Catalysts ◽  
The Difference ◽  
Kinetics Of ◽  
Alumina Catalysts

Kinetics of isomerisation of cyclohexene to methylcyclopentene proceeding as parallel reaction to hydrogenation of cyclohexene to cyclohexane on cobalt-molybdenum catalysts of different composition has been measured. The surface acidity of these catalysts was estimated from the difference in the adsorption of toluene and heptane which was measured by chromatographic method. In a series of catalysts containing molybdenum the acidity parallels isomerisation activity. Cobalt on alumina catalysts and alumina itself have greater acidity but exhibit lower isomerisation activity compared to the catalysts containing molybdenum.

Model for Epitaxial growth of Cobalt on CU(100)

1989 ◽  
Vol 160 ◽  
Author(s):  
Dimitri D. Vvedensky ◽  
Shaun Clarke
Keyword(s):  
Epitaxial Growth ◽  
Growth Kinetics ◽  
Solid Model ◽  
Free Energies ◽  
Diffusion Parameters ◽  
The Difference ◽  
Kinetics Of

AbstractThe epitaxial growth kinetics of Co on Cu(100) are investigated with a kinetic solid-on-solid model. Two effects are found to dominate the growth of this system reflecting the difference in surface free energies betweenthe two materials: the difference of diffusion parameters, and the inability of Co to wet Cu(100) at lower temperatures.

Kinetics of mercury accumulation by freshwater biofilms

2017 ◽  
Vol 14 (7) ◽  
pp. 458 ◽  
Author(s):  
Perrine Dranguet ◽  
Vera I. Slaveykova ◽  
Séverine Le Faucheur
Keyword(s):  
Food Webs ◽  
Food Chain ◽  
Microbial Composition ◽  
Biofilm Thickness ◽  
Aquatic Microorganisms ◽  
Uptake Rate Constant ◽  
The Difference ◽  
Accumulation Kinetics ◽  
Kinetics Of ◽  
Hg Accumulation

Environmental contextMercury (Hg) is a major environmental contaminant due to its toxicity, accumulation and biomagnification along the food chain. We demonstrate that Hg accumulation by biofilms, one possible entry point for Hg into food webs, is rapid and depends on biofilm structure and composition. These findings have important implications for the understanding of Hg bioavailability and effects towards aquatic microorganisms. AbstractMercury contamination is of high concern due to its bioaccumulation, toxicity and biomagnification along the food chain. Biofilms can accumulate Hg and contribute to its incorporation in freshwater food webs. Nevertheless, the accumulation kinetics of Hg by biofilms is not well described and understood. The aim of the present study was thus to gain mechanistic understanding of Hg accumulation by biofilms. Kinetics of Hg uptake by biofilms of different ages (e.g. different compositions) was characterised by determining Hg contents in biofilms with and without a cysteine-washing step. Hg accumulation was rapid in both biofilms, with the uptake rate constant of the younger biofilm 10 times higher than that of the older biofilm. Moreover, accumulated Hg reached a plateau at 24h exposure in the younger biofilm, whereas it increased linearly in the older biofilm. The observed difference in Hg uptake by the studied biofilms is likely a result of the difference in biofilm thickness (and thus Hg diffusion inside the biofilm matrix) and microbial composition. These findings have important implications for the understanding of Hg bioavailability and effects towards aquatic microorganisms.

scholarly journals Membrane-permeable luciferin esters for assay of firefly luciferase in live intact cells

1991 ◽  
Vol 276 (3) ◽  
pp. 637-641 ◽  
Author(s):  
F F Craig ◽  
A C Simmonds ◽  
D Watmore ◽  
F McCapra ◽  
M R H White
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cells ◽  
Firefly Luciferase ◽  
Luciferase Expression ◽  
Intact Cells ◽  
Cos Cells ◽  
Escherichia Coli Cells ◽  
Luminescent Signal ◽  
The Difference ◽  
Kinetics Of

Five esters of luciferin were synthesized and compared with native luciferin as substrates for firefly luciferase expressed in live intact mammalian cells. The esters themselves were not substrates for purified luciferase, but four were substrates for a purified esterase and all appeared to be hydrolysed to luciferin within mammalian cells. At a substrate concentration of 0.01 mM, the peak luminescence from the cos cells expressing luciferase was up to 6-fold greater with the esters than with unmodified luciferin. At 0.1 mM, the difference between luciferin and the esters was decreased. The kinetics of the luminescent signal with the different luciferin esters varied significantly, indicating possible differences in the rates of uptake, breakdown and enzyme inhibition. The esters did not support luminescence from Escherichia coli cells expressing firefly luciferase, suggesting a lack of appropriate esterase activity in this particular strain. The esters could be useful for the assay of luciferase expression in intact mammalian cells when luciferin levels are limiting, for example in tissues, and in plants. Alternative luciferin derivatives may allow further improvements in sensitivity.

The kinetics of Ge lateral overgrowth on SiO2

MRS Advances ◽  
2015 ◽  
Vol 1 (23) ◽  
pp. 1703-1708 ◽  
Author(s):  
M. Yako ◽  
N. J. Kawai ◽  
Y. Mizuno ◽  
K. Wada
Keyword(s):  
Growth Kinetics ◽  
Growth Rates ◽  
Growth Process ◽  
Theoretical Calculations ◽  
Film Formation ◽  
Lateral Overgrowth ◽  
Flat Film ◽  
The Difference ◽  
Kinetics Of

ABSTRACTThe kinetics of Ge lateral overgrowth on SiO2 with line-shaped Si seeds is examined. The growth process is described by the difference between the growth rates of Ge on (100) planes (GR100) and <311> facets (GR311). The theoretical calculations well reproduce the growth kinetics. It is shown that narrowing the line-seeds helps Ge coalescence and flat film formation.

scholarly journals Influence of microadditive of carbon dioxide on the kinetics of boiling-up of superheated w-pentane

2021 ◽  
Vol 2039 (1) ◽  
pp. 012027
Author(s):  
S A Perminov ◽  
E V Lipnyagov ◽  
M A Parshakova
Keyword(s):  
High Speed ◽  
Gas Adsorption ◽  
Glass Tube ◽  
Initial Value ◽  
Active Centers ◽  
High Speed Video ◽  
Inner Surface ◽  
Vertical Glass ◽  
Attainable Superheat ◽  
Kinetics Of

Abstract The effect of a low-boiling impurity (CO2 gas <1.5% mol) on the kinetics of boiling-up of superheated n-pentane in a vertical glass tube have been studied by high-speed video (2050 fps). The method of continuous pressure decrease from 2.00 to 0.10 MPa (in the temperature range of 100.2-145.1 °C), as well as the method of measuring the lifetimes of superheated liquids at 0.10 MPa (90.2-134.1 °C) have been used. The inner surface of the tube has two visible defects, one of which defines the boundary of the attainable superheat. After degassing the system, the defects of tube cease to play an appreciable role, the active centers are redistributed. The temperature of the attainable superheat increases from the initial value by 20 °C in tests with gas and by 10 °C in subsequent tests without it. The result obtained may be related to physical gas adsorption on the glass surface during the process of evacuation of the system.

scholarly journals DRYING KINETICS OF OIL PALM FROND WASTE USING SIMPLE BATCH OVEN DRYER

2016 ◽  
Vol 5 (1) ◽  
pp. 1-7
Author(s):  
Abdul Halim ◽  
Bayu Triwibowo
Keyword(s):  
Oil Palm ◽  
Longitudinal Direction ◽  
Experimental Result ◽  
Operation Temperature ◽  
Drying Kinetic ◽  
Oil Palm Frond ◽  
The Difference ◽  
Difference Operation ◽  
Kinetics Of ◽  
Palm Frond

Drying phenomena of oil palm frond waste as agriculture waste was observed using simple batch oven dryer. The operation temperatures were 50, 80 and 120 C. The sample of oil palm frond was weighed periodically every 30 minutes. Moisture content, shrinkage phenomena and drying kinetic model were investigated to the difference operation temperature. Experimental result exhibited that temperature influent significantly to the drying rate. The water transport controlled by diffuse mechanism. Shrinkage occurred in radial direction and decreased the size to almost 65% from initial size. In longitudinal direction almost is not change of size.

Scaling Behavior of Dynamic Hysteresis in Hard PZT Bulk Ceramics under Influence of Compressive Stress

2008 ◽  
Vol 55-57 ◽  
pp. 281-284 ◽  
Author(s):  
N. Wongdamnern ◽  
Athipong Ngamjarurojana ◽  
Supon Ananta ◽  
Yongyut Laosiritaworn ◽  
Rattikorn Yimnirun
Keyword(s):  
Energy Dissipation ◽  
Electric Field ◽  
Mechanical Stress ◽  
Compressive Stress ◽  
Power Law ◽  
Field Amplitude ◽  
Electric Field Amplitude ◽  
Bulk Ceramic ◽  
Compressive Stresses ◽  
The Difference

Effects of electric field-amplitude and mechanical stress on hysteresis area were investigated in partially depoled hard PZT bulk ceramic. At any compressive stress, the hysteresis area was found to depend on the field-amplitude with a same set of exponents to the power-law scaling. Consequently, inclusion of compressive stresses into the power-law was also obtained in the form of < A – Aσ=0 > α E05.1σ1.19 which indicated the difference of the energy dissipation between the under-stress and stress-free conditions.

THE ALTERATION OF INTRACELLULAR ENZYMES: IV. KINETICS OF CATALASE ALTERATION INDUCED BY CHEMICAL AGENTS

1956 ◽  
Vol 34 (1) ◽  
pp. 25-38
Author(s):  
J. Gordin Kaplan ◽  
Woon-Ki Paik
Keyword(s):  
Molecular Level ◽  
Narrow Range ◽  
Intact Cell ◽  
Cellular Level ◽  
Causal Connection ◽  
Rate Limiting Step ◽  
Chemical Agents ◽  
The Difference ◽  
Rate Limiting ◽  
Kinetics Of

The rate with which n-butanol alters the properties of yeast catalase has been studied as a function of temperature and concentration of altering agent. Activation energies for catalase alteration lay within the rather narrow range of 20–23 kcal./mole, thus confirming a prediction made previously on the basis of the difference in energies of activation for heat destruction of altered and unaltered catalases. Alteration by optimal concentration of butanol was a reaction of zero order. Chloroform also altered yeast catalase with an activation energy within this range of μ values. The close agreement in μ values leads us to conclude that the action of these two altering agents, at all concentrations, is characterized by the same rate-limiting step, even though their action differs in other respects. It was concluded that catalase alteration is probably all-or-none on the molecular level, rather than on the cellular level. Alteration was invariably accompanied by a decrease in the size of the treated cells; alteration was sometimes accompanied by changes in the cytochrome spectrum, but there was no causal connection between these two events. These data are consistent with the interfacial hypothesis, which, in its present crude form, pictures alteration as consisting essentially in the desorption of catalase from some intracellular interface at which it is normally bound in the intact cell.

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