scholarly journals Kinetics of Excess CO2 Output during and after Intensive Exercise.

1999 ◽  
Vol 49 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Takahiro YUNOKI ◽  
Masahiro HORIUCHI ◽  
Tokuo YANO
Keyword(s):  
Intensive Exercise ◽  
Co2 Output ◽  
Kinetics Of

Frequency domain analysis of ventilation and gas exchange kinetics in hypoxic exercise

1991 ◽  
Vol 71 (6) ◽  
pp. 2394-2401 ◽  
Author(s):  
H. C. Xing ◽  
J. E. Cochrane ◽  
Y. Yamamoto ◽  
R. L. Hughson
Keyword(s):  
Frequency Domain ◽  
Binary Sequence ◽  
Domain Analysis ◽  
Exponential Model ◽  
Frequency Domain Analysis ◽  
Pseudorandom Binary Sequence ◽  
Warm Up ◽  
Co2 Output ◽  
Gas Exchange Kinetics ◽  
Kinetics Of

The kinetics of O2 up-take (VO2), CO2 output (VCO2), ventilation (VE), and heart rate (HR) were studied during exercise in normoxia and hypoxia [inspired O2 fraction (FIO2) 0.14]. Eight male subjects each completed 6 on- and off-step transitions in work rate (WR) from low (25 W) to moderate (100–125 W) levels and a pseudorandom binary sequence (PRBS) exercise test in which WR was varied between the same WRs. Breath-by-breath data were linearly interpolated to yield 1-s values. After the first PRBS cycle had been omitted as a warm-up, five cycles were ensemble-averaged before frequency domain analysis by standard Fourier methods. The step data were fit by a two-component (three for HR) exponential model to estimate kinetic parameters. In the steady state of low and moderate WRs, each value of VO2, VCO2, VE, and HR was significantly greater during hypoxic than normoxic exercise (P less than 0.05) with the exception of VCO2 (low WR). Hypoxia slowed the kinetics of VO2 and HR in on- and off-step transitions and speeded up the kinetics of VCO2 and VE in the on-transition and of VE in the off-transition. Frequency domain analysis confined to the range of 0.003–0.019 Hz for the PRBS tests indicated reductions in amplitude and greater phase shifts in the hypoxic tests for VO2 and HR at specific frequencies, whereas amplitude tended to be greater with little change in phase shift for VCO2 and VE during hypoxic tests.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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