scholarly journals Methods for the determination of organic substances in water and fluvial sediments

1987 ◽  
Keyword(s):  
Fluvial Sediments ◽  
Organic Substances

The Perchloric Method for the Determination of Sulfur in Rubber

1934 ◽  
Vol 7 (4) ◽  
pp. 730-735
Author(s):  
Ernest Kahane
Keyword(s):  
Nitric Acid ◽  
Perchloric Acid ◽  
Organic Substance ◽  
Present Author ◽  
General Idea ◽  
Organic Substances ◽  
Gutta Percha ◽  
Higher Temperature ◽  
As If

Abstract The problem of the determination of sulfur in rubber has been dealt with extensively in the literature, and it seems as if discussions and descriptions of new technic are nowhere nearly ended yet. The determination is so essential, and its rapid and precise execution is of such importance in industrial technic, that efforts in this direction should not be regarded as wasted. In 1926 and in 1927 Le Caoutchouc et La Gutta-Percha contained two articles in which the present author discussed the conditions of the determination of sulfur in rubber and then proposed the use of a new oxidizing mixture, not mentioned previous to that time, which involved the destruction of organic substances by perchloric acid. This method consisted simply in the attack on a 1-gram sample of rubber by 10 cc. of nitric acid (d. 1.39) and 5 cc. of perchloric acid (d. 1.61). Upon heating, attack by the nitric acid takes place, and this is followed by evaporation of the excess nitric acid, then at a little higher temperature there is an attack by the perchloric acid, which oxidizes the rest of the organic substance completely. This publication was concerned much more, in the determination of sulfur by the perchloric method, with the general idea of the destruction of organic substances than it was with the precise details of carrying it out. The technic had been studied somewhat superficially, as is shown by the text of the article itself.

scholarly journals An improvement of calcium determination technique in the shell of molluscs

2009 ◽  
Vol 52 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Cristiane Soído ◽  
Maurício Carvalho Vasconcellos ◽  
Antônia Gonçalves Diniz ◽  
Jairo Pinheiro
Keyword(s):  
Hydrogen Peroxide ◽  
Nitric Acid ◽  
Experimental Model ◽  
Calcium Content ◽  
Conventional Technique ◽  
Organic Substances ◽  
Complexometric Method ◽  
Wet Weight ◽  
Calcium Determination

The complexometric method is usually applied to quantitative calcium determination in different materials; however the application of this method to calcium determination in molluscs shells infers significant interferences to the results. The snail Bradybaena similaris, a terrestrial gastropod, was used as experimental model to the improvement of this method. The shells were calcinated and dissolved in nitric acid, the hydrogen peroxide was also used to clarify the medium after the acid addition. The calcination procedure and the use of nitric acid reduced the significantly the interferences, allowing a major degree of destruction of the organic substances of the shell. The improvement of the calcium determination technique usually employed showed calcium content of 874.24 ± 56.617 mg of CaCO3/g of ash in comparison to the conventional technique that allowed the determination of 607.79 ± 67.751 mg of CaCO3/g of shell, wet weight.

scholarly journals Determination of crystallization enthalpies of some organic peroxides by a differential isothermal calorimeter

2021 ◽  
pp. 90-94
Keyword(s):  
Supercooled Liquids ◽  
Sublimation Enthalpy ◽  
Residual Pressure ◽  
Heat Conducting ◽  
Dicumyl Peroxide ◽  
Organic Substances ◽  
Fusion Temperature ◽  
The Difference ◽  
Isothermal Calorimeter

We developed a method for determination of the crystallization enthalpy of organic substances in a heat-conducting calorimeter at a temperature close to 298 K. Crystallization was conducted in the MID-200 calorimeter using an ampoule technique. The volume of ampoules, which contain the supercooled liquids, was approximately 0.2 cm3. The residual pressure was 650 Pa to lessen the heat loss. A few crystals of the material under investigation were employed as the crystallization centers. Based on the results of the experiment, the crystallization enthalpies of dicumyl peroxide, peroxyoctanoic acid and di-tert-butylperoxy isophthalate were determined. The vaporization and sublimation enthalpies of peroxyoctanoic acid were assessed using an ampoule method in the calorimeter. It was established that dicumyl peroxide which was supercooled 14 K below the fusion temperature exhibited a 20% increase in crystallization enthalpy as compared with that calculated from the difference between vaporization and sublimation enthalpy. At the same time, the crystallization enthalpy of peroxyoctanoic acid supercooled by 5 K was equal to that calculated from the difference between vaporization and sublimation enthalpy within the limiting experimental error. The received data show that the proposed method is promising for determining the heat of crystallization of liquids that are able to exist in a supercooled state during some time.

scholarly journals Determination of the biological efficiency of microbial transformation of organic substances of champignon substrates using biodestructors and their importance as organic fertilizer of plants

2020 ◽  
pp. 94-110
Author(s):  
T. Ivanova ◽  
K. Podmarkova ◽  
S. Gruzinsky ◽  
M. Patyka ◽  
I. Chabanyuk
Keyword(s):  
Winter Wheat ◽  
Root System ◽  
Organic Fertilizer ◽  
Microbial Transformation ◽  
Stem Length ◽  
Biological Efficiency ◽  
Organic Substances ◽  
Spent Mushroom Substrate ◽  
Model Object

Goal. Determination of the biological effect of microbial transformation of organic substances of mushroom substrates for the use of biodestructors. Methods. The subject of the study was the used waste substrate after growing mushrooms. The biodestructors Extrakon and Bionorma Destructor were used for the transformation of organic substances of champignon substrates. Winter wheat ‘Smuglyanka’ variety was used as a test object. Research methods: biotechnological, biochemical, microbiological, statistical, light microscopy. Results. Scientific research was carried out and the literature data on the study of waste mushroom substrates and their use as an organic fertilizer were summarized. The monitoring of the possibilities was carried out using substrates after mushroom cultivation. The influence of domestic Extrakon and the Bionorma Destructor on spent mushroom substrates was studied. Established the benefits of using microfertilizer Extrakon and Bionorma Destructor on spent champignon substrates when growing agricultural plants using the example of winter wheat. The research results showed that when using an extract from a spent mushroom substrate, the stem length of the model increases 43.15% longer, and the root length is 1.17% longer, compared to distilled water. When we used an extract from a spent mushroom substrate fermented by Extrakon, the stem length of the model object is 25.12% longer, in comparison with the control, it is 79.11% longer. The length of the roots is 35.66% more compared with the use of an extract from an unfermented spent mushroom substrate, compared with the control — 37.24% more. When Destructor Bionorma was used, the growth of the model object is inhibited. Conclusions. Preparation Extrakon with a spent mushroom substrate in plants, the root system increases due to this, and the feeding area increases. This is due to the fact that the preparation Extrakon is designed for introduction into the soil and for its use the beneficial microflora of the soil is activated, transforms the components of the spent liver substrate, which are then absorbed by the plants and positively affect the nutrition of the root system.

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