The expense of repair and maintenance of private and public sewage systems in Germany runs to about 100 billion US $. This primarily affects concrete pipes and brickwork sewers. Approximately 40 per cent of the damage can be attributed to corrosion by biogenous sulfuric acid attack as a result of long flow periods and insufficient ventilation of waste water. The report deals with investigations...

Electrolytic manganese dioxide (EMD) was prepared by using gas diffusion electrode (GDE) instead of traditional hydrogen evolution cathode. Sulfate acid’s effects on the cell voltage, the current efficiency, the electro-catalytic activity and the lifetime of GDE are studied. The results show that as the concentration of sulfuric acid increases, the current efficiency increases, while the cell v...

nano silica sulfuric acid as a solid acid, was described to be an effective catalyst for one-pot three-component reaction of kojic acid, aryl aldehydes and indoles for the preparation of 2-substituted aryl (indolyl) kojic acid derivatives. the catalyst was prepared by combination of chlorosulfonic acid to nano silica gel. the size of nanoparticles were observed with sem.all prepared compounds w...

the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...

The electron capture gas liquid chromatography test method for chick edema factor has been modified by replacing the alumina column s t ep with an additional sulfuric acid cleanup and a caustic wash which permits a reduction in sample cleanup time. Samples are subjected to double preliminary sulfuric acid cleanup and caustic wash and extracted each time with t r imethyl pentane. The final extra...

A number of the components of the tissues contain in their molecules either phosphoric or sulfuric acid. The phosphoric acid radicle is contained in the monoand polynucleotides, and the sulfuric acid radicle in chondroitinand mucoitin-sulfuric acids. In all these compounds the acid radicle is linked in ester form to either a carbohydrate or a polyhydric alcohol. On long acquaintance with substa...

formaldehyde in small quantities is commonly analyzed by spectrophotometric methods. one of the most-commonly used spectrophotometric techniques for this purpose is based on the reaction with chromotropic acid. because of its simplicity, sensitivity, selectivity and its low cost, it is still widely used. investigations for replacing the concentrated sulfuric acid with other acids or using more ...