The Kinetics of Seed Imbibition: Controlling Factors and Relevance to Seedling Vigor

2015 ◽  
pp. 93-115 ◽  
Author(s):  
Christina W. Vertucci
Keyword(s):  
Controlling Factors ◽  
Seedling Vigor ◽  
Seed Imbibition ◽  
Kinetics Of

Polymeric Film Dialysis in Organic Solvent Media for Cleanup of Organic Contaminants

1990 ◽  
Vol 73 (2) ◽  
pp. 290-293 ◽  
Author(s):  
James N Huckins ◽  
Mark W Tubergen ◽  
Jon A Lebo ◽  
Robert W Gale ◽  
Ted R Schwartz
Keyword(s):  
Organic Contaminants ◽  
Gel Permeation Chromatography ◽  
Controlling Factors ◽  
Polymeric Film ◽  
Membrane Diffusion ◽  
Model Compounds ◽  
New Approach ◽  
Organic Solvent Media ◽  
Fish Lipid ◽  
Kinetics Of

Abstract Dialytic enrichment, using a nonpolar polymeric film or membrane, is proposed as a new approach for the separation of organic contaminants from fish lipid. Nonpolar organochlorine analytes diffuse from the fish lipid through a polyethylene membrane into cyclopentane. Separations of 48 h or less in duration afforded excellent recoveries for all analytes tested and removed 93% of the fish oil. Kinetics of membrane diffusion and possible controlling factors are elucidated for selected analytes and model compounds. Potential advantages of this technique over conventional lipld-removal methods such as gel permeation chromatography include simplicity, large sample capacity, reduced solvent requirements, and amenability to interfacing in-line with other enrichment modules.

scholarly journals Imbibition Rates in Film-coated Shrunken-2 Sweet Corn (Zea mays) Seeds

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 552A-552
Author(s):  
Tina Wilson ◽  
Robert Geneve ◽  
Brent Rowell
Keyword(s):  
Seed Treatment ◽  
Sweet Corn ◽  
Membrane Damage ◽  
Film Coating ◽  
Seedling Vigor ◽  
Fresh Weight ◽  
Significant Difference ◽  
Film Treatment ◽  
Lag Period ◽  
Kinetics Of

Mutant endosperm associated with shrunken-2 sweet corn possesses a high osmotic potential that increases the rate of imbibition. Membrane damage associated with the rapid influx of water during imbibition can play a role in the poor emergence and seedling vigor associated with sweet corn germination. Film-coating as a seed treatment has been used to improve germination and vigor in sweet corn. This improvement may be associated with alterations in the kinetics of imbibition. Two seed lots of shrunken-2 sweet corn, low-vigor `Even Sweeter' and high vigor `Sugar Bowl', were treated with a polymer film-coating and evaluated for differences in water uptake. Imbibition curves were established for nontreated and film-coated seeds. Seeds were weighed every hour for 6 hours and showed a significant difference between the two treatments in fresh weight for both cultivars. This pattern continues throughout the imbibition phase of germination and continues into the lag period. Bulk conductivity tests resulted in no significant mean difference between untreated and film treated seeds after 24 hours. Film treatment assumes characteristics of a hydrophilic polymer. Electrolyte leakage is not reduced and imbibition rate increases by 18% for both varieties of film-coated seeds.

scholarly journals The kinetics of photosynthesis

1935 ◽  
Vol 117 (804) ◽  
pp. 218-239 ◽  
Keyword(s):  
Surrounding Medium ◽  
Controlling Factors ◽  
Primary Reaction ◽  
Complete Understanding ◽  
Initial State ◽  
Living Plant ◽  
Dark Reaction ◽  
Whole Process ◽  
Rate Of Photosynthesis ◽  
Kinetics Of

The influence of the various controlling factors on the rate of photosynthesis is one of the most interesting problems met with in the study of the living plant. If the photosynthetic cycle be considered as a problem in physical chemistry, the three important controlling factors are temperature, intensity of irradiation, and concentration of carbon dioxide in the surrounding medium. During recent years accurate measurements have been made by Warburg and by Emerson of the influence of each of these on the rate of photosynthesis, but no explanation of that influence has been put forward. Of the three controlling factors, the most important is the temperature, since an explanation of the whole process must depend on a complete understanding of the relation between the velocity of photosynthesis and the temperature. It is obvious from the fact that the velocity increases with the temperature that there must be associated with the primary photosynthetic reaction a dark reaction which has a temperature coefficient. This was first recognized by F. F. Blackman (1905), who also proved that when the intensity of illumination is very small the rate of photosynthesis becomes independent of the temperature, a fact which was later confirmed by Warburg (1919). It is evident from this that the Blackman reaction cannot be the precursor of the primary photosynthetic reaction, and there seems little doubt that it is the restoration to its initial state of the chlorophyll which has undergone some change as the result of the primary reaction (Emerson and Arnold, 1932, a ).

A new probe for reaction kinetics—the spectrum of scattered light

1969 ◽  
Vol 2 (4) ◽  
pp. 315-349 ◽  
Author(s):  
Yin Yeh ◽  
R. N. Keeler
Keyword(s):  
Reaction Mechanisms ◽  
Scattered Light ◽  
Life Forms ◽  
Enzymic Activity ◽  
Life Cycles ◽  
Controlling Factors ◽  
Metallic Ions ◽  
The Subject ◽  
Living Organisms ◽  
Kinetics Of

The rates of reaction and reaction mechanisms in biological systems are the controlling factors in the metabolism and life cycles of all living organisms. Nevertheless, very little is known today about the details of these processes, particularly in more complicated life forms. For example, addition of certain metallic ions to an enzymic matrix can cause gross changes in enzymic activity (Brewer & Weber, 1966); just how these ions specifically enter into enzymic reactions is a subject of intense interest. The nature of the kinetics of bonding in nucleic acids is also the subject of much research (Eigen, 1967).

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

1995 ◽  
Vol 53 ◽  
pp. 256-257
Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss
Keyword(s):  
Electron Beam ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Quantum Effect ◽  
Line Drawing ◽  
Chemical Vapor ◽  
Environmental Cell ◽  
Engineering Changes ◽  
Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

Investigation of irradiation-induced nucleation processes in silicon and germanium

1995 ◽  
Vol 53 ◽  
pp. 224-225
Author(s):  
Harry A. Atwater ◽  
C.M. Yang ◽  
K.V. Shcheglov
Keyword(s):  
Room Temperature ◽  
Crystal Size ◽  
Initial Distribution ◽  
Engineering Control ◽  
Size Evolution ◽  
Silicon And Germanium ◽  
Ge Quantum Dot ◽  
And Control ◽  
Germanium Quantum Dots ◽  
Kinetics Of

Studies of the initial stages of nucleation of silicon and germanium have yielded insights that point the way to achievement of engineering control over crystal size evolution at the nanometer scale. In addition to their importance in understanding fundamental issues in nucleation, these studies are relevant to efforts to (i) control the size distributions of silicon and germanium “quantum dots𠇍, which will in turn enable control of the optical properties of these materials, (ii) and control the kinetics of crystallization of amorphous silicon and germanium films on amorphous insulating substrates so as to, e.g., produce crystalline grains of essentially arbitrary size.Ge quantum dot nanocrystals with average sizes between 2 nm and 9 nm were formed by room temperature ion implantation into SiO2, followed by precipitation during thermal anneals at temperatures between 30°C and 1200°C[1]. Surprisingly, it was found that Ge nanocrystal nucleation occurs at room temperature as shown in Fig. 1, and that subsequent microstructural evolution occurred via coarsening of the initial distribution.

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