Effect of Moisture Variations on Curing Rate of GR-S

1949 ◽  
Vol 22 (3) ◽  
pp. 775-785
Author(s):  
Ian C. Rush ◽  
S. C. Kilbank

Abstract Variations which are beyond experimental error have occurred in the rate of curing of GR-S control and production lot samples tested in this laboratory. It is believed that other laboratories in the synthetic rubber industry have encountered similar variations. Changes in the moisture content of the compounded stock at the time of curing have been suspected of causing the fluctuations in the rate of curing. Several papers on the effect of moisture on the rate of curing of GR-S have dealt largely with relatively high moisture contents. However, this investigation was undertaken to correlate the 300 per cent modulus with the moisture contained in the stock at the time of cure. Rupert and Gage observed that, in testing a large master batch of GR-S at intervals, variations in the rate of curing and modulus values beyond experimental error occurred without any apparent relation to time of standing. The same authors have shown that both GR-S raw polymer and compounded stock absorbs or adsorbs moisture from the air, the amount depending on the humidity of the air. Braendle and Wiegand have shown that the moisture content of rubber-grade carbon black during storage can vary from 0 to 4 per cent. Samples of black taken in this laboratory between December 1946 and March 1947 varied from 0.2 to 2.5 per cent moisture. Under the same conditions at which the black contained 1.0 per cent moisture, the other pigments (sulfur, zinc oxide and mercaptobenzothiazole) each contained roughly 0.7 per cent moisture. Two previous papers have shown that the moisture retained in a mixed batch varies in proportion to, but is less than, the moisture added to dry pigments. Both authors, however, used relatively inaccurate means to determine the water retained, and were interested in higher moisture contents than mixed batches would normally contain.

1979 ◽  
Vol 59 (4) ◽  
pp. 911-916 ◽  
Author(s):  
R. N. SINHA ◽  
N. D. G. WHITE ◽  
H. A. H. WALLACE ◽  
R. I. H. McKENZIE

The effects of various seed moisture contents in hulless (cv. Terra) and hulled oats (cv. Random) on susceptibility to mite infestation and on mycofloral growth and germination loss were studied at weekly intervals. Fat acidity values were determined for Terra oats only after 4 wk of storage. Moisture content-relative humidity adsorption and desorption curves were determined for Terra at 22 °C and at relative humidities of 35–100%. Terra oats, which had a higher level of Penicillium infection at 90–100% RH than Random oats, lost viability more rapidly than Random. Fat acidity values of Terra increased rapidly from 35 mg KOH/100 g of seed to 87–118 mg KOH/100 g of seed, only when seeds were stored at 90–100% RH. Terra offered a more favorable substrate for the multiplication of the mites Tyrophagus putrescentiae, Acarus farris, and Lepidoglyphus destructor than did Random. With the exception of susceptibility to mite infestation, safe storage criteria are similar for hulled and hulless oats at usual moisture contents.


1946 ◽  
Vol 24f (6) ◽  
pp. 430-436
Author(s):  
R. L. Hay ◽  
Jesse A. Pearce

Dried sugar–egg powders, obtained from a commercial Canadian source, were adjusted to 1.4, 2.8, and 3.2% moisture and stored at 40°, 80°, and 120° F. from 1 to 52 weeks. Quality of the powder was assessed by measurement of fluorescence, potassium chloride value, pH, and foaming volume. The rate of deterioration increased with an increase in moisture content at 80° and 120° F. The effect of moisture content on fluorescence and potassium chloride values was negligible at 40° F., but high moisture in powders stored at this temperature accelerated the development of acidity and the loss in baking quality as assessed by foaming volume.Packing in carbon dioxide, nitrogen, and in vacuo had a slight beneficial effect on dried sugar–egg powder.


2011 ◽  
Vol 282-283 ◽  
pp. 47-50
Author(s):  
Xue Dong Feng ◽  
Yan Fei Ma

Volatilization of diesel oil in sand columns was conducted at the ambient temperature of 20 °C by spilling oil on the sand surface. The weight loss of oil was determined by pre and post weight of the sand columns and desiccant was measured on an electronic balance. The aim of this paper was to investigate the effect of moisture content on the volatilization of diesel oil in sand. The results show that the diesel oil and water in sand both volatilize at a linear rate with respect to time. The largest volatilization mass of diesel oil and water reach when the moisture contents are 8% and 20% respectively. Appropriate water content can help to pull the oil contaminants to the surface of the sand.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 577c-577
Author(s):  
Noël Pallais

True potato seed of Atzimba × 104.12LB (intermediate dormancy) was dried to seed moisture contents ranging from 3.85 to 12.5% (dry wt basis) and was stored for 2 years at 30, 15 and 5°C. Seed was tested for various germination and seedling vigor criteria at 4 month intervals. Seed dormancy and viability were better preserved at seed moisture levels below 7% and as temperature decreased. High moisture (>9%) was lethal to seed stored at 30°C. TPS should be stored at <5% seed moisture content. Under this condition seed dormancy in the genotype studied was lost after about 12 months at 30°C.


1965 ◽  
Vol 16 (3) ◽  
pp. 301 ◽  
Author(s):  
JS Gladstones ◽  
CM Francis

Seeds of Lupinus angustifolius were given X-ray doses of 2.5, 5, 10, and 20 kr at each of 12 moisture contents ranging from 6.1 to 18.1 % (wet weight basis). Various measures of injury were recorded in the X1 generation, and the types and rates of mutations in the X2. At moisture contents below 16%, total mutation rates were closely correlated with X1 injury. Injury and mutation rate decreased with increasing moisture up to 11–12% moisture, and thereafter remained at a constant minimum up to 16%. Between 16 and 18% moisture there was again an increase in X1 injury, but not in mutation rate. Between 6 and 12 % moisture, a linear relationship was found between moisture content and the logarithm of the dose required to cause a given level of injury or mutation. A possible mechanism for such a pattern of protection is discussed. Lethal mutations increased as a proportion of all mutations as dose and mutation rate increased. There were also proportionately more lethals at high moisture contents than in lower moisture treatments giving the same mutation rates. It is concluded that lethal and seedling chlorophyll-deficient mutations could be misleading when used as indicators of total and viable mutation rates, and that, contrary to the conclusions of some previous authors, no advantage is likely to be gained in practical breeding work from irradiating at high seed moisture contents.


Soil Research ◽  
1966 ◽  
Vol 4 (2) ◽  
pp. 165 ◽  
Author(s):  
N Collis-George ◽  
MJ Rosenthal

Examination of the existing outflow methods reveals that none of the available methods consider membrane impedance without simultaneously involving subjective curve matching. A method is proposed that meets both these requirements and also allows determination of hydraulic conductivity after only small changes of moisture content; the results are therefore easier to interpret. A comparison is made between results obtained from the proposed method and from published outflow methods, as well as from the horizontal infiltration and 'air-pressure' methods. The results obtained exhibit hysteresis for both diffusivity and hydraulic conductivity as functions of moisture content. An hypothesis explaining occurrence of hysteresis in hydraulic conductivity at low moisture contents is presented. It is concluded that the proposed outflow method is experimentally suited to the dry end of the moisture content range, because of the restriction imposed at high moisture contents by the membrane impedance being large relative to the sample impedance. A simple criterion to determine the range of validity of the method is proposed.


2006 ◽  
Vol 46 (7) ◽  
pp. 933 ◽  
Author(s):  
M. E. Dowling ◽  
A. C. Schlink ◽  
J. C. Greeff

Moisture in greasy wool is associated with wool yellowing, fleece rot and fly strike, whereas the high moisture content of wool fabric is related to desired woollen fabric traits. This paper reports on a simple gravimetric method of determining greasy and clean wool moisture contents to determine fleece moisture heritability. The moisture index of greasy wool has a heritability of 0.37 ± 0.04 and phenotypic correlations of –0.31 ± 0.02 with yield, 0.69 ± 0.01 with suint index and 0.50 ± 0.01 with Methylene Blue absorption. The moisture index of greasy wool was strongly genetically correlated with yield (–0.48 ± 0.06), suint index (0.93 ± 0.03), Methylene Blue absorption (0.92 ± 0.03) but not significantly genetically correlated with clean wool moisture absorption (0.18 ± 044). Moisture absorption of clean wool has a very low heritability of 0.02 ± 0.03. The correlations between moisture index and suint index suggest that greasy fleece moisture index is primarily determined by suint index. The implications of variation in the moisture index of wool on fleece rot and fly strike are discussed.


1963 ◽  
Vol 54 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Gordon Surtees

Dispersion behaviour in adults of the saw-toothed grain beetle, Oryzaephilus surinamensis (L.), was studied under controlled laboratory conditions. The effect of density, temperature and moisture content on surface dispersion was studied using groups of insects in jars of 500 g. grain and vertical dispersion by using groups of insects in thin vertical plates of wheat held between two sheets of glass. The ethological basis of group behaviour was investigated by using isolated individuals.Over the range of conditions used, 1–10 per cent, of the individuals comprising the groups studied appeared on the surface of the grain. In grain at 14 per cent, moisture content, at 25°C., 3·4 per cent, of the group appeared on the surface. A greater proportion was found on the surface of grain at 9 per cent, moisture content than at higher moisture contents at all temperatures tested (15–35°C.). At all moisture contents, surface numbers were relatively high at 15°C.In grain at 14 per cent, moisture content and 25°C., individuals moved vertically and laterally at random but were more active in the evening than in the morning. In grain at 9 per cent, moisture, there was marked irritability, and at 15°C. and 14 per cent, moisture, there was continual but slow movement without any detectable diurnal pattern of activity. Activity was reduced at 30°C., and at 25°C. it was reduced in grain of 17 per cent, moisture content.The significance of these results is discussed in relation to the detection of populations, group formation and the initiation of foci of heating in patches of damp grain.


1946 ◽  
Vol 19 (3) ◽  
pp. 773-780
Author(s):  
Ian C. Rush

Abstract Moisture has been discussed as a factor which may give rise to variable rates of cure of GR-S. This moisture may be present in GR-S itself or in the compounding ingredients used. Accordingly, a program was initiated in the spring of 1944 to establish the influence of moisture, not only on the rate of cure of GR-S, but also on its physical properties. Since that time two papers have been published on this subject by other investigators. The results reported here verify some of the conclusions drawn by these investigators but seem to be at variance with others. In this study various proportions of water were added in the following ways : by premixing with carbon black, by adding directly on the mill rolls at the completion of normal milling, and by soaking GR-S crumb in water. Curing curves were obtained for each batch, and were used to evaluate the rate of cure. To eliminate day-to-day variations in physical properties due to error in testing methods, three batches of different moisture contents were mixed and tested on the same day. This same group was then remixed and tested on successive days until at least three batches had been tested for each moisture content and each method of addition. The averages of the individual results (stress-strain data and percentage moisture retained) on batches to which the same percentage of water was added, were then considered free from day-to-day variations.


2018 ◽  
Vol 36 (9-10) ◽  
pp. 1648-1668 ◽  
Author(s):  
Zun-Guo Zhang ◽  
Shu-Gang Cao ◽  
Yong Li ◽  
Ping Guo ◽  
Hongyun Yang ◽  
...  

Intermolecular forces that act between moisture and the atoms of the coal structure have a significant influence on methane adsorption- and desorption-induced deformation in coal. After analyzing the porous characteristics and existing forms of moisture in coal, both the adsorption-induced swelling and the desorption-induced shrinkage deformation experiments were carried out under the conditions of varying moisture content, constant temperature, and variable equilibrium pressure. Both the swelling and shrinkage volumetric strains with different coal moisture contents were fitted by Langmuir-type equations in which the fitting coefficients were functions of the moisture content. It was found that there is a lag between the swelling curve and the corresponding shrinkage curve, and a variable known as the hysteresis rate was defined to illustrate this characteristic. A mathematical model of swelling and shrinkage deformation that considers the effect of moisture content was established based on the experimental results and analysis.


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