Collagen-fibril matrix properties modulate the kinetics of silica polycondensation to template and direct biomineralization

2016 ◽  
Vol 31 (3) ◽  
pp. 311-320 ◽  
Author(s):  
Jennifer L. Kahn ◽  
Necla Mine Eren ◽  
Osvaldo Campanella ◽  
Sherry L. Voytik-Harbin ◽  
Jenna L. Rickus
Keyword(s):  
Collagen Fibril ◽  
Matrix Properties ◽  
Image Position ◽  
Kinetics Of

Abstract

Kinetics of reactions of Ni contact pads with Si nanowires

2011 ◽  
Vol 26 (17) ◽  
pp. 2282-2285 ◽  
Author(s):  
Nicholas S. Dellas ◽  
Michael Abraham ◽  
Sharis Minassian ◽  
Chito Kendrick ◽  
Suzanne E. Mohney
Keyword(s):  
Si Nanowires ◽  
Image Position ◽  
Kinetics Of

Abstract

Annealing experiments on CO2-bearing jadeite glass: an insight into the true temperature dependence of CO2 speciation in silicate melts

2001 ◽  
Vol 65 (6) ◽  
pp. 701-707 ◽  
Author(s):  
Y. Morizet ◽  
S. C. Kohn ◽  
R. A. Brooker
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Negative Charge ◽  
Silicate Melts ◽  
True Temperature ◽  
Carbonate Group ◽  
Image Position ◽  
Kinetics Of ◽  
Annealing Experiments ◽  
Insight Into

AbstractThe thermodynamics and kinetics of CO2 speciation in silicate melts have been studied by measuring the concentration of CO2mol and carbonate in jadeite glass annealed at 575, 450 and 400°C. Assuming that the reaction is1where CO2mol..Obr represents a CO2 molecule weakly bonded to a bridging oxygen in the network and CO3 represents a bridging carbonate group with no net negative charge, ΔH for the reaction is –17 (+4/–8) kJ mol−1 and ΔS is –24 (+6/–9) J K−1 mol−1. The rate of equilibration of the species was measured at each temperature and the rate constants were deduced. The temperature dependence of the rate constants was used to determine the activation energy of the forward and reverse reactions which are 68 (+3/–31) kJ mol−1 and 86 (+1/–69) kJ mol−1 respectively. The data suggest that CO2mol may be much more abundant in silicate melts than previously assumed on the basis of studies of CO2-bearing glasses. Models of solubility, diffusion, and isotope fractionation should take this into account.

Stimulation Electrodes Based on MnO2 Thin Films: Electrical Properties in Carbonate Buffered Saline

1985 ◽  
Vol 55 ◽  
Author(s):  
Ellen M. Kelliher ◽  
Timothy L. Rose
Keyword(s):  
Manganese Dioxide ◽  
Active Surface ◽  
Alkaline Solutions ◽  
Manganese Acetate ◽  
Proton Diffusion ◽  
Rate Determining Step ◽  
Solid Film ◽  
Image Position ◽  
Saline Solutions ◽  
Kinetics Of

ABSTRACTHydrous manganese dioxide films are being investigated as a new redox material for the active surface of intracortical stimulation electrodes. The films are electrodeposited at room temperature on Pt substrates from a neutral solution of manganese acetate. The electrochemical properties of the films have been evaluated by cyclic voltammetry in neutral saline solutions buffered with bicarbonate. The films undergo a reversible charge injection reaction represented asThe results obtained in electrolytes of different buffer concentrations indicate the film is able to store the most charge in solutions having the lowest buffer capacity. The kinetics of the redox reaction thus favor operation in an acidic or basic environment in agreement with earlier published results. Two different mechanisms are proposed to explain the rate enhancement at the different pH's. In acidic electrolytes the reaction proceeds by dissolution of the film, while in alkaline solutions the rate determining step of proton diffusion in the solid film is increased. For neural stimulation, therefore, electrodes with manganese dioxide films should be pulsed cathodically to insure a neutral or alkaline environment around the electrode and minimize dissolution of the film.

Kinetics of Alumina Removal from a Calcined Kaolin with Nitric, Sulphuric and Hydrochloric Acids

Clay Minerals ◽  
1970 ◽  
Vol 8 (3) ◽  
pp. 337-345 ◽  
Author(s):  
S. F. Hulbert ◽  
D. E. Huff
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Kinetic Data ◽  
Acid Leaching ◽  
Normal Reaction ◽  
Reaction Equation ◽  
Experimental Conditions ◽  
Image Position ◽  
Calcined Kaolin ◽  
Kinetics Of

AbstractAn investigation of the acid-leaching of a calcined kaolin was made to compare the reaction kinetics of hydrochloric, nitric, and sulphuric acids. The acid concentrations used were 5·9 and 8·6 normal. Reaction temperatures used were 95°, 80° and 60° C.Particular attention was given to finding a reaction equation which would mathematically represent the kinetic data. A nucleation rate equation of the general form, was found to represent these data. Values of m varied from 1·10 to 1·55 depending on the experimental conditions.Under the conditions employed the rate of alumina leaching is fastest with hydrochloric acid, slower with sulphuric acid, and slowest with nitric acid. The rate controlling steps are proposed from the experimental evidence.

Performance and kinetics of Pt–CNT catalyst electrodes in a PEM fuel cell

2012 ◽  
Vol 27 (11) ◽  
pp. 1497-1505 ◽  
Author(s):  
Ayo Samuel Afolabi ◽  
Ambali Saka Abdulkareem ◽  
Sunny Esayegbemu Iyuke ◽  
Hendrick Christoffel Van Zyl Pienaar
Keyword(s):  
Fuel Cell ◽  
Pem Fuel Cell ◽  
Image Position ◽  
Kinetics Of

Abstract

Kinetics of hydrogen in preparing amorphous B5C:H thin films

2011 ◽  
Vol 26 (7) ◽  
pp. 867-873 ◽  
Author(s):  
Ruqiang Bao ◽  
Douglas B. Chrisey ◽  
Daniele J. Cherniak
Keyword(s):  
Thin Films ◽  
Image Position ◽  
Kinetics Of

Abstract

Nucleation and growth of Si quantum nanocrystals in silicon-rich oxide films

1996 ◽  
Vol 54 ◽  
pp. 234-235
Author(s):  
S. C. Mehta ◽  
D. A. Smith ◽  
M. R. Libera ◽  
J. Ott ◽  
G. Tompa ◽  
...  
Keyword(s):  
Amorphous Matrix ◽  
Bulk Diffusion ◽  
Nucleation And Growth ◽  
Light Emitters ◽  
Si Nanocrystals ◽  
Uniform Dispersion ◽  
Silicon Nanocrystallites ◽  
Image Position ◽  
Silicon Based ◽  
Kinetics Of

The observation of photoluminescence and electroluminescence in Si nanocrystals has generated renewed interest in these novel silicon based materials for their possible application as light emitters and detectors. Silicon Rich Oxide (SRO) films with a uniform dispersion of silicon nanocrystallites in a wider bandgap SiO2 matrix manifest electroluminescence and photoluminescence in the infrared and visible portions of the spectrum. Understanding the nucleation and growth kinetics of these crystallites in amorphous matrix is of critical importance in the fabrication of future optoelectronic devices. One route to the fabrication of Si nanocrystals is by the crystallization of amorphous SiO2-x. Consider the case when x=1. The reaction leading to the formation of Si crystallites can be written as;(1)The nucleation, growth and coarsening processes of Si nanocrystals each require bulk diffusion of Si atoms through the amorphous matrix.

Spreading Kinetics of Molten 60Sn40Pb on Higher Melting Temperature Pb-Sn Alloy Substrates

1995 ◽  
Vol 390 ◽  
Author(s):  
H. Conrad ◽  
Z. Guo ◽  
D. Y. Jung
Keyword(s):  
Activation Energy ◽  
Contact Angle ◽  
Melting Point ◽  
Kcal Mole ◽  
Depth Of Penetration ◽  
Spherical Cap ◽  
Solid Diffusion ◽  
Time Exponent ◽  
Image Position ◽  
Kinetics Of

ABSTRACTThe spreading of molten 60Sn40Pb drops on higher melting point Pb-Sn alloy substrates (3 to 10 wt.% Sn) was investigated for reflow temperatures of 205° to 300°C. Following melting the drop assumed the form of a slightly flared, spherical cap with some penetration into the substrate beneath the contact area. The effects of time and temperature on the contact angle θ and the depth of penetration h were of the formwhere the apparent activation energy Q was 4.2 kcal/mole for θ and 16 kcal/mole for h. The time exponent m (negative for θ and positive for h) decreased with temperature from ∼ 0.2–0.3 at 205°C to ∼0.05 at 260° and then increased again at higher temperatures. The magnitude of Q for θ is in accord with that for the viscosity of molten Pb-Sn alloys and that for h with a combined liquid-solid diffusion involved in the dissolution. Further work is however needed to identify unequivocally the mechanisms which govern the wetting in these duplex Pb-Sn alloy systems.

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