Influence of Moisture Content of Carbon Black on Rubber Properties

1942 ◽  
Vol 15 (1) ◽  
pp. 216-219
Author(s):  
Leonard H. Cohan ◽  
C. R. Johnson

Abstract The moisture content of carbon black should be kept approximately constant if maximum accuracy in rubber testing is to be attained. In this laboratory we have found it convenient to equilibrate blacks at about 30 per cent humidity, under which condition most rubber channel blacks adsorb 1.5 to 2.0 per cent water. In the case of most of the properties of tread stocks, this precaution decreases the average deviation from the mean value in any series of experiments. In the case of extrusion tests, the effect of adsorbed moisture is so great that the use of a standard moisture content, or at least the determination of moisture content at the same time as the black is milled for extrusion, is necessary if reproducible results are to be expected.

Author(s):  
Offurum Julius Chigozie ◽  
C.M. Morgan

The water content determination of two maize species (Yellow corn- and White corn- ) located at Ohaji in Imo State of Nigeria were  considered in this study. This was motivated by the regular reported cases of the seed post-harvest spoilages, especially in the local communities. And the moisture content of a particular seed could vary according to the various location of crop, presumably due to the soil texture. The moisture content of a given crop seed can influence its storage value, as well as its choice of selection during manufacturing processes. It was, thus, necessary to determine the moisture content of the two maize species (white and yellow corn) from Ohaji in Imo State of Nigeria, in order to identify their dispositions, especially during storage. Modified High Constant Temperature Oven method, as prescribed by the International Seed Testing Association (which involves preliminary pre-drying and grinding), was employed, at a temperature of 102oC. This involved the use of dry-weight technique, which is expressed as a percentage of the dry weight of the seeds. The procedure for each sampling was replicated accordingly, and the mean value identified as the actual result. The moisture content for Sample A (white corn) was found to be 31.7%, while that of Sample B (yellow corn) was found to be 21.5%, which shows that the yellow corn would always have longer storage value than the white corn. As any change in the seed moisture content has a way of affecting its storage life, it is advisable not to store the white corn longer than it could be applied in the yellow corn for a better storage value.Keywords: Determination, Moisture Content, White Corn, Yellow Corn, Dry-weight Basis


1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.


1966 ◽  
Vol 16 (01/02) ◽  
pp. 038-050 ◽  
Author(s):  
Ulla Hedner ◽  
Inga Marie Nilsson ◽  
B Robertson

SummaryThe plasminogen content was determined by a casein method in plasma and serum from 20 normal volunteers. The mean plasminogen content was found to be 10.1 ACU (the arbitrary caseinolytic unit defined in such a way that using a 3% casein solution and a digestion time of 20 min. at 37°C, 10 ACU gave an extinction of 0.300). No difference between serum and plasma regarding the plasminogen content was found.Plasminogen was determined in drained and drained plus washed clots prepared from 2 ml plasma. The highest values found in the drained clots were 0.9 ACU/clot and 0.2 ACU/clot in the drained plus washed clots.Plasminogen was also determined in drained and drained plus washed clots prepared from plasma with added purified plasminogen. The plasminogen was recovered in the washing fluid. According to these tests, then, purified added plasminogen is washed out of the clots.The plasminogen content of 20 thrombi obtained post mortem was also determined. The mean value was found to be 0.7 ACU/cm thrombus. Judging from our results, the “intrinsic clot lysis theory” is not the main mechanism of clot dissolution.


2010 ◽  
Vol 35 (4) ◽  
pp. 543-550 ◽  
Author(s):  
Wojciech Batko ◽  
Bartosz Przysucha

AbstractAssessment of several noise indicators are determined by the logarithmic mean <img src="/fulltext-image.asp?format=htmlnonpaginated&src=P42524002G141TV8_html\05_paper.gif" alt=""/>, from the sum of independent random resultsL1;L2; : : : ;Lnof the sound level, being under testing. The estimation of uncertainty of such averaging requires knowledge of probability distribution of the function form of their calculations. The developed solution, leading to the recurrent determination of the probability distribution function for the estimation of the mean value of noise levels and its variance, is shown in this paper.


1967 ◽  
Vol 56 (1) ◽  
pp. 99-106 ◽  
Author(s):  
K. Leybold ◽  
J. Rieper ◽  
L. Weissbecker

ABSTRACT A simple method for the determination of cortisol-binding capacity is described. For saturation of the cortisol-binding proteins, plasma samples are incubated with an excess of cortisol. In the next step NADPH and liver microsomes of female rats are added. The microsomal Δ4-3-ketosteroid hydrogenase only reduces non protein-bound cortisol to tetrahydrocortisol-5α. Then the steroids are extracted by dichloromethane, and after some purification steps analyzed by fluorometry. Tetrahydrocortisol gives practically no fluorescence. The cortisol determined by this method corresponds to protein-bound cortisol and indicates the extent of cortisolbinding capacity. Precision and accuracy of the method were found to be good. The values of cortisol-binding capacity obtained by our method are compared with the results of other authors. The mean value of adult men was 25.5 ± 3.4 μg/100 ml, that of pregnant women, mens IX-X, 42.3 ± 4.2 μg/100 ml.


Author(s):  
Mingjian Zhang ◽  
Feng Huang ◽  
Qing Chen ◽  
Le Wang ◽  
Haisheng Wang ◽  
...  

A mathematical model was established to predict the mean value and variance of tobacco strip during drying processing, based that the physical and chemical properties of tobacco strip as agriculture products show probability distributions. The results show that the model can predict the mean value of moisture content at different times, and there is a certain deviation in predicting the variance of moisture content at initial stage of drying process. However, the prediction value of the variance of tobacco strip is much more accurate while the moisture content is between 8% and 10%, which is the interval of quality requirements.Keywords: tobacco strip; drying; mean value;variance model.  


1999 ◽  
Vol 42 (3) ◽  
pp. 235-240
Author(s):  
A. Jacková ◽  
P. Siklenka ◽  
J. Pleva

Abstract. In a study with 12 calves on milk nutrition, the course of methemoglobinemia as well as ttansrenal passage of nitrates and nitrites after single per os administrations of 4 g NaNO2 per animal and 30 g KNO3 per animal in the form of water Solutions has been observed. The response of the organism of calves to per os administered doses of sodium nitrite and potassium nitrate was observed by the determination of tlie methemoglobin percentage in blood and the nitrate and nitrite content in urine before the administration ofthe respective dose and after h 1, 2, 3 and 4 after the administration. A significant elevation in the values of methemoglobin was recorded after h 2 after the administration of 4g NaNO3 per animal. The mean value of methemoglobin in blood was 18.84% of total hemoglobin. A slight decline in the values occurred as early as after h 3 after the administration. Of clinical signs, cyanosis of visible mucosae was observed. The highest nitrite and nitrate values in urine were determined after h 2 after per os administration of 4g NaNO2, With the administration of 30g KNO3 per animal, the most pronounced elevation in methemoglobinemia was observed after h 3, when the means values of methemoglobin was 11,75%. Of clinical signs, only slight cyanosis of mucosae was detectable. Maximum values of nitrates in urine of experimental calves after h 3 after the administration of 30 g KNO3 per animal, with the mean value of 29,9 mM NO3−1 clearly demonstrate a good transrenal passage of nitrates in calves on milk nutrition.


1980 ◽  
Vol 26 (9) ◽  
pp. 1275-1277 ◽  
Author(s):  
Y Yamaguchi

Abstract I describe a method for measuring high-density lipoprotein phospholipids. Magnesium chloride and dextran sulfate are used to precipitate all low-density and very-low-density lipoproteins. The supernate contains only high-density lipoproteins, the phospholipid concentration of which is determined by an enzymic method. The precision of the method (CV) is 2.35% (10 repeated assays), and the mean value for HDL-phospholipids was 1006 (SD 248) mg/L for 30 apparently healthy subjects. I used electrophoresis and enzymic color development to confirm the presence of HDL-phospholipids. Results are compared with those obtained by an ultracentrifugation method.


1960 ◽  
Vol 15 (2) ◽  
pp. 225-228 ◽  
Author(s):  
John H. Knowles ◽  
William Newman ◽  
Wallace O. Fenn

At the end of a normal expiration the subject inhaled a given volume of gas mixtures containing different concentrations of CO2 in O2 from 5 to 17%. These were held in the lung for 3 and then again for 12 seconds and were then expired and analyzed. Analyses were made with an infrared analyzer and times were obtained from the graphical record. If the rate of change of CO2 tension is plotted against the mean CO2 tension a straight line results which passes through zero rate at the tension which equals the tension of CO2 in the mixed oxygenated venous blood. From the slope of this straight line it is possible to calculate the cardiac output if the lung volume and slope of the CO2 dissociation curve of the blood are known. Data are presented from 37 experiments on 10 subjects. The method is believed to be theoretically sound but has not been validated as a practical clinical method. Occasional erratic points were obtained, especially in untrained subjects. The standard error of the mean value for venous CO2 tension was 1.9 mm Hg. Submitted on July 13, 1959


1981 ◽  
Author(s):  
I Rákóczi ◽  
Gy Geró ◽  
J Demeter ◽  
I Gáti

It is known that platelet hyperaggregation observed in diabetic patients is, at least in part, due to an increased activity of the endoperoxide-thromboxane forming metabolic pathway. It was interesting to determine the platelet malondialdehyde /MDA/ production in normal and diabetic pregnancies. Following individuals have been studied: /I/ twenty-five healthy non-pregnant volunteers; /II/ thirty women in third trimester of non-complicated pregnancies; /III/ twenty two diabetic pregnant women without retinopathy; /IV/ fifteen diabetic pregnant women with retinopathy. Platelet MDA production following N-ethyl-maleimide induced aggregation was measured according to Stuart et al. The mean value of MDA production was similar in volunteers and normal pregnant women /SDM, 7.07±0.73 nmoles MDA per 109 platelets; 7.22±0.81/. The mean MDA production in diabetic women without retinopathy was slightly but nonsignificantly higher than that in normal pregnant women /7.57±1.02; p>0.05/. The corresponding value in diabetic women with retinopathy was significantly higher than the values in the other three groups /8.47±0.82; p<0.01/. These data suggest that the activation of prostaglandin synthetic pathway /measured by MDA/ is significantly increased in diabetic pregnancy complicated by retinopathy. The increase of platelet prostaglandin synthesis in diabetic pregnancy might play an important role in initiating and/or promoting the small-vessel complications of placenta.


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