Studies on the Determination of Non-Metallic Inclusions in Iron and Steel. I : Determination of Non-Metallic Inclusions in Plain Carbon Steel and Silicon Steel

Non-metallic inclusions in iron and steel are usually determined by hot nitric acid, electrolytic or chlorine methods. The present authors studied the adaptabilities of these three methods in the analyses of plain carbon steel and silicon steel, and obtained the following results : In plain carbon steel, these methods were easily carried out but hot nitric acid method gave a lower value for silica than other methods, and electrolytic method gave a higher value for ferrous oxide and manganese oxide than other methods. After all, chlorine method was most convenient and accurate. Hot nitric acid and electrolytic methods gave somewhat higher value for silica in silicon steel, but if more chlorine would be passed than in the usual case, chlorine method would give correct results

Influences of Arsenic on the Analysis of Iron and Steel. III : Determination of Titanium and Molybdenum in Iron and Steel

When titanium was reduced directly by liquid zinc amalgam and titrated with standard ferric solution immediately after the dissolution of steel sample, the presence of 0.15 per cent of arsenic caused about 0.03 per cent high result for titanium. So the removal of arsenic as arsenic tribromide with bromine in hydrochloric acid solution was recommended. In the gravimetric or volumetric determination after the separation of titanium with sodium thiosulfate or ammonium phosphate, there was no interference by arsenic. For the determination of molybdenum in the volumetric method, it was necessary to remove arsenic as tribromide. In the gravimetric method with α-benzoin oxime, however, arsenic had no influence

Influence of Arsenic on the Analysis of Iron and Steel. II : The Determination of Copper and Manganese in Iron and Steel

The influence of arsenic on the determination of copper and mangnese in iron and steel was studied. On the determination of copper, there was no direct influence of arsenic in the sodium thiosulfate separation method and hydrogen sulfide separation method. But in the separating procedure of copper from iron with hydrogen sulfide, the amount of iron coprecipitated with sulfides became larger by the presence of arsenic, and so the reprecipitation of ferric hydroxide was necessary for the perfect separation of copper. It was found also that arsenic had no effect on the determination of manganese by any of the usual methods

Determination of Manganese in Iron, Steel and Ferromanganese. I : Determination of Manganese in Iron and Steel

The suitable concentration of acids and other conditions in ferrous-permanganate method after the oxidation with persulfate were studied for the determination of manganese in Iron and steel and the following results were obtained : (1) Acid concentration : using 2g of ammonium persulfate in total volume of 200ml, manganese was determined in the concentration range 1.2～2.4N sulfuric acid, 0.53～1.20N nitric acid and 0.6～1.2N mixed acid of sulfuric acid and nitric acid (3:1) but manganese could not be determined in acidic solution with perchloric acid. (2) Boiling time : the time of boiling of the solution for the oxidation of manganese by ammonium persulfate using silver nitrate was 5 min, during which the decomposition of permanganic acid occurred. (3) Influence of phosphoric acid : when 1g of iron and 10mg of manganese were present, the existence of 4ml of phosphoric acid (sp. gr. 1.7) was advisable. (4) The suitable procedure for the determination of manganese in iron and steel was established and the analysis was carried out with several samples and reliable results were obtained

Polarographic Determination of Tin and Antimony in Iron and Steel

For the estimation by ploarography of small amounts of tin and antimony contained as impurities in iron and steel, it was necessary to remove the effect of interference of iron. These impurities were, therefore, separated from iron by co-precipitating with manganese dioxide. The precipitate was decomposed with hydrochloric acid and hydrogen peroxide, and tin was reduced with aluminium foil to Sn^ and its polarogram was taken in ammonium chloride solution. Antimony solution was heated with sulfuric acid till the evolution of white fume to reduce it to Sb^ and the polarogram was taken in 0.1N hydrochloric acid. 0.02～0.1 per cent of tin and 0.005～0.1 per cent antimony in iron and steel could be determined

Influence of Arsenic on the Analysis of Iron and Steel. I : The Determination of Sulfur and Phosphorus in Iron and Steel

The effects of arsenic on the determinations of sulfur and phosphorus in iron and steel were studied, and a method for avoiding the interference of arsenic was established. It was found that the determination of sulfur was not affected by arsenic for any of the combustion, evolution, and gravimetric methods, but that arsenurretted hydrogen evolved during the evolution method so that it seemed advisable to have this gas absorbed in a solution of potassium permanganate in a bottle connected to the end of the apparatus. Determination of phophorus by the usual molybdate method was found to give higher value in proportion to the content of arsenic in the sample, but this error could be lessened to the range of analytical error by the precipitation of phosphomolybdate at low temperatures

Determination of Manganese in Iron, Steel and Ferromanganese. II : Determination of Manganese in Ferromanganese

The suitable concentration of acids and other conditions in ferrous-permanganate method after oxidation with persulfate for the determination of manganese in ferromanganese were studied and the following results were obtaind. (1) On the relation between the amount of manganese and the requisite amount of phosphoric acid, using about 2g of ammonium persulfate in total volume of 200ml, the amount of phosphoric acid added must be increased with the increase of manganese content. But the amount of phosphoric acid necessary was smaller, when the total volume is made to 400ml and 4g of ammonium persulfate are used. (2) On the concentration of the acid, using 4g of ammonium persulfate in total volume of 400ml, 4～28mg of manganese was determined in the concentration range of 1.4～2.6N H_2SO_4 or 0.6～1.0N mixed acid of H_2SO_4 and HNO_3 (3:1). (3) Boiling the solution for 1～5 minutes gave quantitative results while a somewhat lower values were obtained when boiled more than 6 minutes. (4) From the above results, the suitable analytical procedures for the determination of manganese in ferromanganese were established and the analysis of several actual samples were carried out and good results were obtained

A Simplified Determination of Microquantity of Carbon in Iron, Steel and Ferro-Alloy

In order to determine rapidly and accurately microquantity (below 0.1 per cent) of carbon in iron, steel and ferro-alloys, 0.5～1g of the sample was taken, carbon dioxide gas generated by its combustion was solidified by passing through a trap chilled in liquid air, and the solid carbon dioxide was vaporized and allowed to permeate a definite vacuum, the volume being read on the manometer. The analytical results by this method agreed well with those by gravimetric method within a mean standard deviation of 0.0005 per cent in low-carbon steel, and well agreeing results were also obtained with chromium metal and manganese metal. The time required for the analysis by this method was 24～26 minutes

Association between BDNF and clinical response in OCD

Aim: Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family, and it promotes the development and function of dopaminergic and serotonergic neurons. The Met allele of the BDNF Val66Met polymorphism is associated with a decrease in activity-dependent secretion of BDNF compared with the Val allele, and a number of studies have provided evidence for the association between this polymorphism and obsessive-compulsive disorder (OCD). The purpose of this study was to investigate whether this functional variant of the BDNF gene is associated with OCD and treatment response in patients with OCD in the Japanese population. Methods: We first performed a case–control association study between the BDNF Val66Met polymorphism and OCD (175 cases and 2,027 controls). Then, we examined an association between this polymorphism and treatment response in 96 patients with OCD. Results: We found no significant association between the Met allele and OCD risk or between the Met allele and treatment responses to selective serotonin reuptake inhibitors or serotonin reuptake inhibitor with an atypical antipsychotic (P>0.05). Conclusion: Our results suggest that the BDNF Val66Met polymorphism may not be associated as a risk factor for developing OCD or with therapeutic response in patients with OCD in the Japanese population