SORPTION OF WATER AND ALCOHOL VAPORS BY CELLULOSE

1937 ◽  
Vol 15b (1) ◽  
pp. 13-37 ◽  
Author(s):  
J. K. Russell ◽  
O. Maass ◽  
W. Boyd Campbell
Keyword(s):  
Water Vapor ◽  
Vapor Pressures ◽  
Propyl Alcohol ◽  
Cellulose Structure ◽  
Alcohol Vapor ◽  
Long Period ◽  
Tensile Forces ◽  
Wood Pulps ◽  
Sorption Curve ◽  
Degree Of Sorption

Measurements were made of the amount of water vapor sorbed by beaten and unbeaten samples of kraft, unbleached sulphite and bleached sulphite wood pulps at relative vapor pressures ranging from 0 to 100%. Beating of the pulp made practically no difference to the degree of sorption at any relative vapor pressure. This indicated that beating caused no change in the hydration of the cellulose. Measurements were made of the sorption of methyl alcohol vapor by bleached sulphite, kraft and groundwood, and of the sorption of propyl alcohol vapor by bleached sulphite and cotton, all previously wetted with water and then dried. After sorption of alcohol, evacuation at room temperatures did not completely remove the alcohol. Measurements were also made of sorption of propyl alcohol by bleached sulphite and by cotton which had been dewatered by washing with propyl alcohol. The shape of the sorption curve was different for these samples, and the residual alcohol after evacuation was less. After a sample of cotton had been dried over phosphorus pentoxide in vacuo for a long period it was found to hold 0.35% of water by weight which could be removed by heating the cellulose to 100 °C. This was regained from the pentoxide on cooling the cellulose.The data are explained on the hypothesis that the crystalline submicroscopic elements of the cellulose structure are drawn together by internal tensile forces during the evaporation of the sorbed liquid, and that bonding between these elements may take place by the growing together of the crystal elements, leaving the structure internally stressed. On absorption, dissolution of these bondings takes place and the stresses are relieved as liquid enters the structure.

Thickness of the Still Air Layer Adhering to Perforated Plastic Plates and Fabric

1988 ◽  
Vol 58 (2) ◽  
pp. 86-90 ◽  
Author(s):  
Kozo Tsubouchi
Keyword(s):  
Water Vapor ◽  
Humidity Sensor ◽  
Unit Area ◽  
Water Vapor Pressure ◽  
Sample Surface ◽  
Hole Diameter ◽  
Vapor Pressures ◽  
Wide Range ◽  
Vapor Pressure Gradient ◽  
Surface Construction

The thickness of the still air layer adhering to perforated plastic plates and a fabric was investigated in terms of the water vapor pressure gradient in the zone of diffusion above the samples. The water vapor pressures above the samples were determined from measurements using a temperature and relative humidity sensor. To analyze the thickness of the still air layer for a wide range of evaporation rates, the hole diameter and the number of holes per unit area were changed and the measurements were under different temperature and humidity/gradient conditions. The thickness of the still air layer corresponded to a distance of 10 mm from the sample surface and was not related to the surface construction and materials.

scholarly journals Methods for Determining Mold Development and Condensation on the Surface of Building Barriers

Buildings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 4 ◽  
Author(s):  
Aleksander Starakiewicz ◽  
Przemysław Miąsik ◽  
Joanna Krasoń ◽  
Lech Lichołai
Keyword(s):  
Water Vapor ◽  
Vapor Condensation ◽  
Mold Growth ◽  
Vapor Pressures ◽  
Climate Conditions ◽  
Outdoor Climate ◽  
Surface Condensation ◽  
Water Vapor Condensation ◽  
Calculation Results ◽  
Temperature Factors

The article presents four equivalent methods for checking mold growth on the surface of building barriers and checking water vapor condensation on their surface. Each method applies to two parallel phenomena that may occur on a building barrier. The first method is to calculate and compare temperature factors. In the second method, the characteristic humidity in the room is calculated and compared. The third method is to calculate and compare the characteristic temperatures in the room. The fourth method is based on the calculation and comparison of characteristic water vapor pressures. Three boundary conditions are presented for each method and phenomenon: when a given phenomenon can occur, when it begins or ends, and when it does not occur. The presented methods systematize the approach to the problem of mold development and surface condensation. The presented calculation results relate to the selected building barrier functioning in specific indoor and outdoor climate conditions. The calculation results confirm the compliance of the presented methods in identifying the phenomenon of mold growth or condensation on the surface of the barrier. A graphical interpretation of the results for each method with periods of occurrence or absence of a given phenomenon is also presented.

Preparation of matched reagents for use with the Scholander gas analyzer

1977 ◽  
Vol 43 (1) ◽  
pp. 164-166
Author(s):  
R. G. Collins ◽  
V. W. Musasche ◽  
E. T. Howley
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Volume Change ◽  
Quantitative Method ◽  
Gas Analysis ◽  
Vapor Pressures ◽  
Gas Analyzer ◽  
Atmospheric Air ◽  
Fixed Acid

Scholander's method of gas analysis requires that the solutions for CO2 absorber, O2 absorber, and acid-rinse be matched in terms of water vapor tension throughout the analysis. Any difference in vapor pressure between either or both of the absorbing solutions and the indicator drop (composed of acid-rinse) will produce a measurable volume change which cannot be attributed to the presence of absorbable gases. This paper describes a practical and quantitative method for preparing reagents whose vapor pressures are matched. A fixed acid-rinse formulation was used throughout. A CO2 absorber prepared from 1.35 N KOH and an O2 absorber prepared from 0.76 N KOH were both matched in terms of vapor pressure with Scholander's acid-rinse solution. Analysis of atmospheric air provided a check on the accuracy of the technique. The values obtained were O2 20.94%, CO2 0.03%, and N2 (balance) 79.04%.

scholarly journals Experimental Investigations on Some Synthetic Leucite Rocks under Water Vapor Pressures

1976 ◽  
Vol 52 (9) ◽  
pp. 469-472 ◽  
Author(s):  
Alok K. GUPTA ◽  
Kenzo YAGI ◽  
Yu HARIYA ◽  
Kosuke ONUMA
Keyword(s):  
Water Vapor ◽  
Experimental Investigations ◽  
Vapor Pressures

Isotopic Exchange Between Hydrogen and Water Vapor over Supported Metal Catalysts. Part I. Kinetics of the Exchange

1972 ◽  
Vol 50 (12) ◽  
pp. 1900-1906 ◽  
Author(s):  
J. H. Rolston ◽  
J. W. Goodale
Keyword(s):  
Water Vapor ◽  
Transfer Rate ◽  
Water Vapor Pressure ◽  
Adsorbed Water ◽  
Deuterium Atom ◽  
Supported Metal Catalysts ◽  
Vapor Pressures ◽  
Order Dependence ◽  
Rate Limiting ◽  
Kinetics Of

Some rate data for the transfer of a deuterium atom tracer between hydrogen and water vapor, catalyzed by platinum supported on γ-alumina, are reported. Above 100 °C the transfer rate measured at 1 atm total pressure is shown to be free of mass transfer effects, and obeys an initial first order dependence on water vapor for vapor pressures less than 10 Torr. A near zero order dependence is observed at higher water vapor pressures. At temperatures below 100 °C the transfer rate is essentially independent of water vapor pressure between 5 and 100 Torr suggesting that surface adsorbed water is involved in the rate limiting transfer step.

EFFECT OF WATER VAPOR ON THE FORMATION OF MODIFICATIONS

1965 ◽  
Vol 43 (9) ◽  
pp. 2522-2529 ◽  
Author(s):  
R. A. Kuntze
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Atmospheric Pressure ◽  
Calcium Sulfate ◽  
Water Vapor Pressure ◽  
Exothermic Peak ◽  
Vapor Pressures ◽  
Ambient Water ◽  
Rate Of Heating ◽  
Calcium Sulfate Hemihydrate

The two recognized forms of calcium sulfate hemihydrate can be identified by the position of a relatively small exothermic peak in their differential thermograms. Hemihydrates prepared at various water vapor pressures up to 760 mm Hg were found to produce this exothermic peak in a position which is characteristic for the β-form. These results indicate that α-hemihydrate cannot be made at atmospheric pressure, as was previously suggested on the basis of heat solution measurements. The typical differential thermogram of α-hemihydrate is only obtained with material made by dehydration in solution or by autoclaving. The effect of ambient water vapor pressure on the position of the three peaks that occur in the differential thermogram of CaSO4•2H2O has also been studied. It was found that the incipient temperature of the second endothermic peak, corresponding to the transition of hemihydrate to soluble anhydrite, is displaced independent of the rate of heating from 145 °C to 187 °C with increasing water vapor pressures up to 760 mm Hg. This indicates that, for each temperature, a threshold water vapor pressure exists, above which soluble anhydrite cannot be formed.

Determining the period of the long-period activity of the water-vapor maser in W75N

2000 ◽  
Vol 26 (1) ◽  
pp. 38-48 ◽  
Author(s):  
E. E. Lekht ◽  
V. V. Krasnov
Keyword(s):  
Water Vapor ◽  
Long Period

THE EXCHANGE OF OXYGEN-18 BETWEEN CELLULOSE, ADSORBED WATER, AND WATER VAPOR

1959 ◽  
Vol 37 (11) ◽  
pp. 1829-1833 ◽  
Author(s):  
A. R. G. Lang ◽  
S. G. Mason
Keyword(s):  
Water Vapor ◽  
Adsorption Isotherm ◽  
Adsorbed Water ◽  
Regenerated Cellulose ◽  
Vapor Pressures ◽  
Dilution Technique

The adsorption on regenerated cellulose of water at vapor pressures of 0 to 40 μ Hg has been measured by an oxygen-18 dilution technique. The results showed that cellulose may be dried to less than 0.04% moisture by evacuation at 70 °C. The adsorption isotherm was compared with that of Taylor for viscose rayon.It was also shown that oxygen-18 does not exchange between cellulose and water.

scholarly journals A System for Controlling Water Potential in Seed Germination Research

HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 364-366 ◽  
Author(s):  
Phil S. Allen ◽  
Donald B. White ◽  
Karl Russer ◽  
Dave Olson
Keyword(s):  
Water Vapor ◽  
Seed Germination ◽  
Water Potential ◽  
Constant Temperature ◽  
Filter Paper ◽  
Water Reservoir ◽  
Vapor Pressures ◽  
Salt Solutions ◽  
Petri Dishes ◽  
Germinating Seeds

An inexpensive system for maintaining desired water potentials throughout seed germination was developed. During hydration, a water reservoir at the base of inclined petri dishes allowed continual saturation of filter paper on which seeds were placed. During dehydration, seeds were exposed to equilibrium vapor pressures above saturated salt solutions. Constant temperature, necessary to prevent condensation of water vapor, was achieved via a small (0.2 A) fan that furnished and circulated heat throughout an insulated chamber in which salt solutions were placed. By operating the chamber above ambient laboratory temperature, interior cooling was not required. The system allowed manipulation of the rate, degree, and frequency of dehydration episodes to which germinating seeds were exposed.

Sorption of Water Vapor by Gelatin-Based Polymers: Estimation of Rate and Degree of Sorption Using the Spin-Probe Method

2020 ◽  
Vol 75 (5) ◽  
pp. 269-273
Author(s):  
E. M. Zubanova ◽  
E. N. Golubeva ◽  
M. Ya. Melnikov ◽  
E. A. Nemets ◽  
V. I. Sevastianov
Keyword(s):  
Water Vapor ◽  
Spin Probe ◽  
Probe Method ◽  
Spin Probe Method ◽  
Sorption Of Water Vapor ◽  
Degree Of Sorption
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