Importance of Temperature and Humidity Control in Rubber Testing. II—Resistance to Abrasion

1929 ◽  
Vol 2 (4) ◽  
pp. 680-697
Author(s):  
W. A. Gibbons ◽  
J. M. Bierer ◽  
E. R. Bridgewater ◽  
D. F. Cranor ◽  
C. R. Park ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Experimental Error ◽  
Negligible Effect ◽  
Stress Strain ◽  
Humidity Control ◽  
Temperature Changes ◽  
Constant Relative Humidity ◽  
Temperature And Humidity ◽  
Cent Relative Humidity ◽  
Great Error

Abstract This study shows that in determining resistance to abrasion the temperature of the room or cabinet should be controlled within ± 1 ° C. in order to avoid significant errors in the results from this source. Below are shown the percentage differences per degree Centigrade obtained with each of the stocks. It must be remembered that this probably holds only over the range of temperatures studied and might change rapidly outside of this range. As the temperature changes from 15 ° C. to 35 ° C., the resistance to abrasion changes per degree Centigrade in the following manner: In the light of the present investigation there will be no great error in results caused by differences in relative humidity either with the raw or vulcanized stock. Where laboratories are equipped to condition raw and vulcanized stock for stress-strain tests, it appears that it would be advisable also to condition samples for determining resistance to abrasion. It would at least tend to produce more nearly uniform results by eliminating possible sources of small errors. As the relative humidity during exposure of raw stock increases from 10 per cent to 100 per cent, the resistance to abrasion per 1 per cent relative humidity changes roughly in the following manner: As these variations are small compared with the experimental error, it is evident that if the relative humidity does not vary over too wide a range its effect may be neglected. The temperature of storing the cured samples while maintaining a constant relative humidity has a negligible effect as in the case of relative humidity. As the temperature increases the resistance to abrasion per degree changes in the following manner:

Memoirs: The Early Embryonic Development of Rhodnius Prolixus (Hemiptera, Heteroptera)

1935 ◽  
Vol s2-78 (309) ◽  
pp. 71-90
Author(s):  
HELEN MELLANBY
Keyword(s):  
Relative Humidity ◽  
Embryonic Development ◽  
Early Development ◽  
Constant Temperature ◽  
Germ Cells ◽  
Rhodnius Prolixus ◽  
Posterior Pole ◽  
Early Embryonic Development ◽  
Temperature And Humidity ◽  
Cent Relative Humidity

1. Eggs of Rhodnius prolixus were incubated at constant temperature and humidity (21° C. and 90 per cent, relative humidity). Eighty-five per cent, was the lowest record of the controls hatched successfully under these conditions. 2. The processes of maturation and fertilization were not studied. 3. Cleavage begins 12-13 hours after incubation. At 25 hours there are 32 nuclei. Yolk-cells are derived from cleavage nuclei, and they multiply by mitosis up to 50 hours. Blastoderm formation is complete after 55-60 hours of incubation. 4. The ventral embryonic rudiment is similar to that of many other insects. As soon as it is formed, germ-cells are budded off at the posterior pole of the egg. 5. The first stage in blastokinesis is fully described. 6. The formation of the mesoderm is by invagination and overgrowth. 7. The endoderm arises from two proliferating areas situated anteriorly and posteriorly. 8. Numerous cells are given off into the yolk during the early development of the embryo. There they disintegrate.

scholarly journals Regulating temperature and relative humidity in air–liquid interface in vitro systems eliminates cytotoxicity resulting from control air exposures

2017 ◽  
Vol 6 (4) ◽  
pp. 448-459 ◽  
Author(s):  
Jose Zavala ◽  
Rebecca Greenan ◽  
Q. Todd Krantz ◽  
David M. DeMarini ◽  
Mark Higuchi ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Liquid Interface ◽  
Humidity Control ◽  
Exposure System ◽  
Temperature And Humidity ◽  
In Vitro Systems ◽  
Air Liquid Interface

Modifications to a VITROCELL exposure system were required to mitigate cytotoxicity caused by the absence of temperature and humidity control.

scholarly journals The Conditions of Temperature and Humidity of the Air between the Skin and Shirt of Man

1932 ◽  
Vol 32 (2) ◽  
pp. 268-274 ◽  
Author(s):  
Kenneth Mellanby
Keyword(s):  
Relative Humidity ◽  
Temperature And Humidity ◽  
Cent Relative Humidity

Methods for measuring the temperature and humidity of the air beneath the shirt are described.Conditions of temperature and humidity under the shirt are described, for a resting person, with external temperatures varying between 0° C. and 41° C., under different atmospheric humidities. The air beneath the shirt varied between 23° C. and 37° C., and 23 and 70 per cent. relative humidity. The saturation deficiency of the air beneath the shirt varied very little—only between 13 and 18 mm.—in all the observations taken.I am indebted to Dr P. A. Buxton for many helpful suggestions and for reading the manuscript. Also to Prof. G. H. F. Nuttall, F.R.S., for drawing my attention to literature on the earlier work.

Effect of a Filter Cover on Temperature and Humidity in a Mouse Cage

1968 ◽  
Vol 2 (2) ◽  
pp. 113-120 ◽  
Author(s):  
M. L. Simmons ◽  
D. M. Robie ◽  
J. B. Jones ◽  
L. J. Serrano
Keyword(s):  
Relative Humidity ◽  
Measured Temperature ◽  
Ambient Conditions ◽  
Fibrous Filter ◽  
Water Filter ◽  
Average Temperature ◽  
Temperature And Humidity ◽  
Cent Relative Humidity ◽  
The Mean ◽  
Heat And Moisture

To determine how a filter cap affects the heat and moisture build-up in a mouse cage, and how that build-up is affected by ambient conditions of temperature and relative humidity, 50 adult female mice were housed 10 per cage in polycarbonate cages, which were covered with a fibrous filter and sealed with a neoprene gasket and hold-down rod. The cages were placed in a chamber which controlled ambient temperature and humidity. Observations were made at 1°F intervals of temperature (68–74°F, 19.9–23.3°C) and at three different relative humidities (40, 55, and 70 per cent). Every 24 hours the chamber conditions were changed, and cages, bedding, water, filter caps, and food were replaced. Three sensors suspended just under the filter cover measured temperature and humidity and transmitted the data to a recorder. The first reading was taken after a 3-hour equilibraiion period, then every 3 hours until the next day's change. By measuring the average temperature and humidity, it was possible to study the differences between cage and ambient conditions. At 68°F (19.9°C) and 40 per cent relative humidity, the mean conditions in the cages were 72°F (22.2°C) and 50 per cent; at the upper limit of 74°F (23.3 °C) and 70 per cent, the mean cage conditions were 78°F (25.5°C) and 75 per cent.

Importance of Temperature and Humidity Control in Rubber Testing. Progress Report of the Physical Testing Commitee, Rubber Division, A.C.S. (Dated Dec. 8, 1927)

1928 ◽  
Vol 1 (1) ◽  
pp. 182-191
Author(s):  
J. E. Partenheimer ◽  
E. R. Bridgwater ◽  
D. F. Cranor ◽  
E. B. Curtis ◽  
J. W. Schade ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Absolute Humidity ◽  
Rubber Compounds ◽  
Physical Testing ◽  
Temperature And Humidity ◽  
Cent Relative Humidity ◽  
Physical Tests ◽  
A Minor ◽  
Mixed Stock ◽  
Testing Room

Abstract The purpose of the work which this committee has undertaken is to determine the effect of the variables which influence the results of physical tests on rubber. The investigation has proven that variations in temperature which may occur from day to day in an uncontrolled testing room may affect the physical tests to as great a degree as a 25 to 40 per cent change in the time of cure, while relative humidity affects the results to only a minor degree. Furthermore, variations in the absolute humidity of the room in which the unvulcanized rubber is stored between the time of mixing and the time of curing may affect the tensile strength and modulus of rubber compounds to as great a degree as does the temperature after curing. It is, therefore, apparent that laboratory tests which are conducted under uncontrolled conditions of temperature and humidity may give highly erroneous results and may even give misinformation which is worse than no information at all. The committee, therefore, recommends that mixed stock prior to curing and cured stock prior to testing be conditioned for not less than twenty-four nor more than twenty-eight hours at 82 deg. F. ± 2 deg. and 45 per cent relative humidity ± 3 per cent and that the testing room be maintained at 82 deg. F. ± 2 deg. If a temperature of 82 deg. F. cannot be maintained for conditioning the mixed stock prior to curing, the committee recommends a relative humidity corresponding to the temperature used which gives an absolute humidity equal to that obtained under the former conditions. The temperature of the testing room should be controlled within the above stated limits, but it is not necessary to control the humidity of the entire room. A small conditioning cabinet in which the standard humidity is maintained has been found to be sufficient.

Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions

1993 ◽  
Vol 51 ◽  
pp. 876-877
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Microstructural Characterization ◽  
Building Blocks ◽  
Quantitative Information ◽  
Physical Models ◽  
Specimen Preparation ◽  
Time Resolved ◽  
Temperature Changes ◽  
Temperature And Humidity ◽  
Microstructured Fluids ◽  
Air Streams

To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

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