Properties of Higher Polymers in Solution. III. The Action of Ultra-Violet Light on Dissolved Rubber

1936 ◽  
Vol 9 (4) ◽  
pp. 570-572 ◽  
Author(s):  
Kurt H. Meyer ◽  
Cesare Ferri
Keyword(s):  
Physical Properties ◽  
Wave Length ◽  
Ultra Violet ◽  
The Other ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Ultra Violet Radiation ◽  
Gutta Percha ◽  
Other Hand ◽  
Violet Radiation

Abstract The action of ultra-violet radiation on rubber has been the object of a long series of investigations. According to van Rossem, rubber is depolymerized under the action of light. Asano on the other hand thinks that ultra-violet light, is able to bring about either polymerization or depolymerization according to its wave-length. More recently Dogadkin and Pantschenkov have carried out experiments in an atmosphere of nitrogen, during the course of which they have found a strong diminution in the viscosity. From this fact they have concluded that light is able to cause depolymerization and micellar degradation. We have undertaken a study of the action of ultra-violet light on rubber in order to prove whether the double cis-linkages of rubber undergo a transposition into trans-linkages, for numerous instances are known where light causes these cis-trans-transpositions. In the case of rubber, one should obtain, therefore, either a hydrocarbon of the gutta-percha type or, if light causes a sort of cis-trans-equilibrium, a hydrocarbon with double cis-linkages distributed irregularly. In our experiments we were extremely careful to exclude oxygen, since some years ago Henri proved that ultra-violet light activates greatly the oxidation of rubber. On the other hand it is known that oxidation causes a diminution in the length of the chains which modifies considerably the physical properties, for example, the viscosity, and which may mask the effect produced by light.

scholarly journals The action of ultra-violet radiation on barium and strontium azides

1939 ◽  
Vol 172 (950) ◽  
pp. 299-314 ◽  
Keyword(s):  
Induction Period ◽  
Alkaline Earth ◽  
Room Temperature ◽  
Wave Length ◽  
Ultra Violet ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Ultra Violet Radiation ◽  
Pre Treatment ◽  
Violet Radiation

The alkaline earth azides decompose at appreciable rates at temperatures above 100° C, and the reactions which occur are of the accelerating type increasing in speed as the 6th-8th power of the time, there being a marked induction period during which the reaction occurs at a negligible rate (Harvey 1933; Marke 1937; Maggs 1939). The decomposition is accelerated and the length of the induction period shortened when the solid is acted upon by β -rays at room temperature before the heat treatment (Garner and Moon 1933; Maggs 1939). It was, therefore, possible that ultra-violet light would cause an acceleration of these reactions in a similar manner. Muller and Brous (1933) have shown that sodium azide is decomposed by ultra-violet light at a rate which is proportional to the intensity and that the threshold wave-length for the decomposition is around 405 m µ . In the present investigation it is shown that barium and strontium azides are decomposed by ultra-violet light at room temperature and that the thermal decomposition of these substances is accelerated by pre-treatment with this radiation.

scholarly journals QUANTITATIVE STUDIES ON THE PHOTOLETHAL EFFECTS OF QUARTZ ULTRA-VIOLET RADIATION UPON PARAMECIUM

1935 ◽  
Vol 18 (4) ◽  
pp. 557-571 ◽  
Author(s):  
A. C. Giese ◽  
P. A. Leighton
Keyword(s):  
Wave Length ◽  
Ultra Violet ◽  
The Other ◽  
Ultra Violet Radiation ◽  
Quantitative Studies ◽  
Controlled Conditions ◽  
Order Of Magnitude ◽  
Intense Light ◽  
Violet Radiation

Paramecia grown under controlled conditions were irradiated at known intensities of light of wave-lengths 2537, 2654, 2804, 3025, and 3130 A. The approximate absorption of the light by the Parmecia was found to be greatest and of the same order of magnitude at the three shortest wave-lengths, considerably less at 3025, and least at 3130 A. Paramecia did not die when irradiated with high dosages of intense light of wave-length 3130 A. At the other wave-lengths 50 per cent vesiculation occurred when between 1012 and 1013 quanta had been absorbed by a Paramecium. This would indicate that a very large number of molecules in a Paramecium are affected before vesiculation occurs.

scholarly journals RESULTS OF IRRADIATING SACCHAROMYCES WITH MONOCHROMATIC ULTRA-VIOLET LIGHT

1935 ◽  
Vol 18 (3) ◽  
pp. 351-355 ◽  
Author(s):  
R. H. Oster ◽  
W. A. Arnold
Keyword(s):  
Cell Division ◽  
Ultra Violet ◽  
Sufficient Data ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Ultra Violet Radiation ◽  
Degree Of Damage ◽  
Multiple Hit ◽  
Violet Radiation

Data obtained on yeast irradiated with monochromatic ultra-violet radiation has been analyzed for the number of quantum hits involved in the production of different degrees of inhibition of cell division, according to the method proposed by Mme. Curie (1929). Sufficient data are not available for a rigorous determination, but the calculated results tend to indicate that a multiple hit to kill relation is followed, that different numbers of hits are involved in the production of different degrees of inhibition, and that this number increases with increase in the degree of damage sustained.

XXII.—Deficiency Effects of Ultra-violet Light in Drosophila melanogaster

1942 ◽  
Vol 61 (3) ◽  
pp. 297-315
Author(s):  
B. M. Slizynski
Keyword(s):  
Drosophila Melanogaster ◽  
Ultra Violet ◽  
Maize Pollen ◽  
X Ray ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Ultra Violet Radiation ◽  
Chromosomal Changes ◽  
Ray Series ◽  
Violet Radiation

Stadler and Sprague in a series of papers (1936) succeeded in demonstrating by a genetical method the effect of ultra-violet radiation in maize pollen, and found that in their experiments in the X-ray series the chromosomal changes are very common, while in the ultra-violet series they are rare.

scholarly journals Studies on air-borne virus infections: II. the killing of virus aerosols by ultra-violet radiation

1943 ◽  
Vol 43 (1) ◽  
pp. 11-15 ◽  
Author(s):  
D. G. ff. Edward ◽  
Dora Lush ◽  
R. B. Bourdillon
Keyword(s):  
Influenza Virus ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Wave Length ◽  
Ultra Violet ◽  
Virus Infections ◽  
Ultra Violet Radiation ◽  
Vaccinia Viruses ◽  
Simplex Virus ◽  
Violet Radiation

The experiments show that rapid and effective sterilization of atmospheres containing atomized particles of influenza and vaccinia viruses, and probably also of herpes simplex virus, can be obtained by ultra-violet radiation of wave-length 2537 A. At least 99 % and probably more of an aerosol of influenza virus was killed by exposure for 6 sec. at. a distance of 2 cm. from either a Hanovia lamp or a G.E.C. ‘Sterilamp’. These findings confirm the work of Wells and his associates who first demonstrated the susceptibility of this virus to ultra-violet radiation (Wells & Brown, 1936; Wells & Henle, 1941). At the same distance the ‘Sterilamp’ produced more than a 99 % kill of vaccinia virus with an exposure of 1 sec. and about a 90 % kill in 0·5 sec. The experiments with herpes were less satisfactory but suggested a similar sensitivity. These results support the view that ‘germicidal’ lamps are likely to be useful in reducing the infectivity of air contaminated with particles from persons suffering from virus infections of the respiratory tract.We wish to acknowledge our indebtedness to the late Sir Patrick Laidlaw who, although his name does not appear as author, largely inspired the investigation and took an active part in it until his death.

Studies on the Joule Effect in Rubber. I. The Thermal Effect on Stretched Vulcanized Rubber

1935 ◽  
Vol 8 (2) ◽  
pp. 174-176
Author(s):  
Yoshio Tanaka ◽  
Shū Kambara ◽  
Hironosuke Fujita
Keyword(s):  
Carbon Black ◽  
Thermal Effect ◽  
Ultra Violet ◽  
Sulfur Compounds ◽  
The Other ◽  
Joule Effect ◽  
Ultra Violet Radiation ◽  
Vulcanized Rubber ◽  
High Heating ◽  
Violet Radiation

Abstract The experiments may be summarized as follows: 1. With an increase in the time of cure, the elongation and heating elongation diminish and the Joule effect increases. 2. An increase in the vulcanization coefficient is followed by a decrease in the elongation and heating elongation and an increase in the Joule effect. The increase in the Joule effect, however, has a limit. 3. An organic accelerator reduces the elongation and heating elongation and increases the Joule effect. 4. The greater the degree of mastication the greater the elongation and the heating elongation and the less the Joule effect. 5. By exposure to ultra-violet radiation, the elongation and heating elongation are increased and the Joule effect decreased. 6. A filler increases the heating elongation and decreases the elongation and the Joule effect. Thus samples with relatively high elongations at a definite tension have relatively high heating elongations and low Joule effects. Such specimens seem to have been affected by the disaggregation and depolymerization of the rubber molecules. The effects of the time of cure, mastication, and exposure to ultra-violet radiation prove this fact. Vulcanization increases the Joule effect, but on the other hand, it is accompanied by a disaggregation and depolymerization of the rubber molecules, so the increase in the Joule effect with the progress of vulcanization has a limit. On vulcanization with an accelerator, the combination of sulfur occurs so rapidly that the increase in the Joule effect is predominant. A filler, such as carbon black, behaves only as a diluent of Joule effect. These results lead to the conclusion that the more highly polymerized rubber molecules and their sulfur compounds seem to be the chief factor in the Joule effect of vulcanized rubber.

scholarly journals Diet and Tuberculosis

1927 ◽  
Vol 26 (2) ◽  
pp. 204-212 ◽  
Author(s):  
Harry Schütze ◽  
S. S. Zilva
Keyword(s):  
Vitamin C ◽  
Guinea Pigs ◽  
Ultra Violet ◽  
The Other ◽  
Cod Liver Oil ◽  
Large Excess ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Fat Soluble Vitamins ◽  
Intraperitoneal Inoculation

Guinea-pigs living on a diet restricted in quantity but not deficient in vitamin C survived inoculation with T.B. but half as long as others which had received a similar diet in abundance.Sodium chaulmoograte did not inhibit the development of the omental tumour that appears in rats after intraperitoneal inoculation with tubercle bacilli.On the other hand, there was some evidence for assuming that a large excess of fat-soluble vitamins in the diet, as supplied by cod-liver oil, inhibits the formation in rats of these tuberculous tumours, but such evidence was by no means conclusive.Similar inhibition of omental infection was obtained on exposing rats to ultra-violet light.Ultra-violet irradiation or the inclusion of large amounts of cod-liver oil in the diet of the rats produced a slight but constant leucocytosis.No evidence was obtained that lack of fat soluble vitamins in their diet renders tubercle infected rats susceptible to tuberculin shock.

Aging of Stretched Rubber

1928 ◽  
Vol 1 (1) ◽  
pp. 106-112
Author(s):  
Arthur Kelly ◽  
Bert S. Taylor ◽  
Webster N. Jones
Keyword(s):  
Direct Relationship ◽  
Strain Curve ◽  
Ultra Violet ◽  
The Other ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Test Strips ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Early Stages

Abstract Sunlight aging under tension of many compounds including the following has been investigated: tire tread shoe upper, tube stocks, golf ball thread, jar rubber, solid tire, bathing cap stock, channel rubber. With some of these stocks the sunlight aging as been compared with unstretched samples by Geer oven, Bierer bomb, and ultra-violet light methods. The stretching of the test strips accelerates deterioration in sunlight, ultra-violet light, and Geer oven. Stretched samples have not yet been tested in the Bierer bomb. The rate of deterioration was not proportional to the degree of stretch in any of the stocks in the early stages of exposure. In sunlight there is a critical elongation for each stock at which the deterioration progresses more rapidly than at any other in the early stages of aging. No direct relationship was found between the results of sunlight aging and the other methods employed. Stretched strips aged in ultra-violet light were found to give softer stress-strain curves than the unaged samples, whereas sunlight aging under the same conditions stiffens the stress-strain curve.

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