The Time Variation in the Water Vapor Bands in Oxygen-Rich Mira Variables

2001 ◽  
pp. 433-438 ◽  
Author(s):  
Mikako Matsuura ◽  
Issei Yamamura ◽  
Hiroshi Murakami ◽  
Takashi Onaka
Keyword(s):  
Water Vapor ◽  
Time Variation ◽  
Mira Variables

Determination of Sorption Rate and Apparent Solid-Side Diffusivity of Pure H2O in Silica Gel Using a Constant Volume/Variable Pressure Apparatus

1991 ◽  
Vol 113 (4) ◽  
pp. 257-263 ◽  
Author(s):  
L. T. Lu ◽  
D. Charoensupaya ◽  
Z. Lavan
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Moisture Content ◽  
Silica Gel ◽  
Time Variation ◽  
Constant Volume ◽  
Variable Pressure ◽  
Test Unit ◽  
Sorption Rate ◽  
Sorption Data

Silica gel-water vapor is commonly suggested as a working media for solar-powered desiccant cooling systems since the system can be regenerated at relatively low temperatures. In the present study the sorption rates of water vapor by regular density silica gel particles were measured in the pressure range of 1–25 torr using a constant volume/variable pressure apparatus. The sorption rate was determined from recorded time variation of water vapor pressure in a test unit of known volume during the sorption process. The mass transfer film resistance was eliminated by evacuating the system and by introducing pure water vapor into the test unit. The apparent solid-side diffusivity was obtained by matching the analytical solution of the simultaneous heat and mass transfer governing equations to the experimental data. The uptake measurements had been performed for three particle sizes of silica gel (150 μm, 1 mm, and 3 mm). The tests were performed sequentially in small steps over a range of initial silica gel moisture content ranging from near zero up to 0.25 kg H2O per kg dry silica gel. The effect of moisture content and particle size on the sorption rate and apparent diffusivity were determined. The effect of charging on time variation of pressure was evaluated and used for correction on all sorption data.

scholarly journals Time variation of SWS spectra of M-type Mira variables

2002 ◽  
Vol 388 (2) ◽  
pp. 573-586 ◽  
Author(s):  
T. Onaka ◽  
T. de Jong ◽  
I. Yamamura
Keyword(s):  
Time Variation ◽  
Mira Variables

scholarly journals Time Variation of SiO Maser Emissions

1980 ◽  
Vol 87 ◽  
pp. 539-540
Author(s):  
Nobuharu Ukita ◽  
Norio Kaifu
Keyword(s):  
Time Variation ◽  
Astronomical Observatory ◽  
Mira Variables

We report a series of observations of the v=1, J=2-1 transition of SiO (86243.28 MHz) toward four Mira variables (o Cet, R Leo, W Hya, and R Cas) and Orion A over the period September 1976 - February 1978. Observations were made with the 6-m mm-wave telescope of the Tokyo Astronomical Observatory. Most of the spectra were taken with an acousto-optical spectrometer with an effective resolution of about 57 kHz.

scholarly journals Time Variation in the Chemical and Isotopic Composition of Volcanic Gas at Mt. Mihara of Izu-Oshima Island, Japan

2019 ◽  
Vol 14 (7) ◽  
pp. 972-977
Author(s):  
Takeshi Ohba ◽  
Muga Yaguchi ◽  
Kana Nishino ◽  
Nozomi Numanami ◽  
◽  
...  
Keyword(s):  
Water Vapor ◽  
Isotopic Composition ◽  
Time Variation ◽  
Excess Enthalpy ◽  
Vapor Condensation ◽  
Hydrogen Gas ◽  
Volcanic Gas ◽  
Water Vapor Condensation ◽  
Pit Crater ◽  
Fumarolic Gas

Volcanic gas was sampled at three fumaroles and one borehole on Mt. Mihara, Izu-Oshima volcano. The fumarolic gas and the borehole steam possessed an excess enthalpy relative to the air saturated with water vapor. The fumarolic gas located west of the pit crater on Mt. Mihara showed a time variation in chemical and isotopic composition. The cause of the variation seems to be an enhancement of water vapor condensation. No similar variation was observed in the fumarolic gas located east of the pit crater, suggesting the above variation is a phenomena localized around the western fumarole. Hydrogen gas was detected in the sampled gases with low concentration. The change in the H2 concentration synchronized among the three fumaroles, suggesting the H2 gas originated in the hydrothermal system developed beneath Mt. Mihara.

scholarly journals The time variation in infrared water-vapour bands in Mira variables

2002 ◽  
Vol 383 (3) ◽  
pp. 972-986 ◽  
Author(s):  
M. Matsuura ◽  
I. Yamamura ◽  
J. Cami ◽  
T. Onaka ◽  
H. Murakami
Keyword(s):  
Water Vapour ◽  
Time Variation ◽  
Mira Variables

Polarimetric Observations of Red Variables: A Study of Gas and Particle Interactions

1979 ◽  
Vol 46 ◽  
pp. 386-408 ◽  
Author(s):  
G. V. Coyne ◽  
I. S. McLean
Keyword(s):  
Wavelength Dependence ◽  
Stellar Atmosphere ◽  
Molecular Absorption ◽  
Absorption Bands ◽  
Absorption And Emission ◽  
Mira Variables ◽  
Stellar Photosphere ◽  
Regular Variable ◽  
Red Supergiants ◽  
Balmer Lines

AbstractIn recent years the wavelength, dependence of the polarization in a number of Mira variables, semi-regular variables and red supergiants has been measured with resolutions between 0.3 and 300 A over the range 3300 to 11000 A. Variations are seen across molecular absorption bands, especially TiO bands, and across atomic absorption and emission lines, especially the Balmer lines. In most cases one can ignore or it is possible to eliminate the effects due to interstellar polarization, so that one can study the polarization mechanisms operating in the stellar atmosphere and environment. The stars Omicron Ceti. (Mira), V CVn (semi-regular variable) and Mu Cephei (M2 la), in addition to other stars similar to them, will be discussed in some detail.Models to explain the observed polarization consider that the continuum flux is polarized either by electron, molecular and/or grain scattering or by temperature variations and/or geometrical asymmetries over the stellar photosphere. This polarized radiation is affected by atomic and molecular absorption and emission processes at various geometric depths in the stellar atmosphere and envelope. High resolution spectropolarimetry promises, therefore, to be a power-rul tool for studying stratification effects in these stars.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

Hydration Chamber for Jeolco 200 Kv Microscope

1970 ◽  
Vol 28 ◽  
pp. 542-543
Author(s):  
V. R. Matricardi ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscope ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Pressure Gradient ◽  
Room Temperature ◽  
List Type ◽  
Type Number ◽  
Equilibrium Vapor Pressure

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied: The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.There should be no pressure gradient across the grid so that specimens can be straddled across holes.Leakage of water vapor to the column should be minimized.

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