Recent trend of the forest fires and climate in Sakha, Siberia was showed by analyzing the fire history and climate data. The following conclusions were obtained. (1) Analysis of forest fire history from the mid 1950 s in Sakha showed that the mean annual number of forest fires and burnt area were at about 500 and 2,700 km2 respectively. The average burnt area has been increasing since the 1990 s. (2) Analysis of the climate in Yakutsk, Sakha from the nineteenth century showed that the mean air temperature rise since 1830 was about 3 °C. The recent remarkable temperature rise began from the 1970 s. (3) The precipitation history from 1890 showed a gradual decrease beginning from the 1970 s. Specially, the daily mean precipitation in fire season(from May to September)was drastically decreased from the 1990 s. These decreases in precipitation may make boreal forests more dry or flammable. Actually, in 2002, large-scale forest fires occurred near Yakustk under these ongoing global warming condition. (4) A detailed analysis of recent precipitation patterns in Yakutsk, Sakha implies that forest fires became large when annual precipitation is smaller than a mean precipitation or 250 mm. (5) Precipitation patterns also had a great effect to forest fires. A considerable amount of rain in June is a key element in controlling fires in Yakutsk. Actually, about 50 mm of precipitation in June of 1995 seemed to suppress forest fires to a level below the fire year. The total precipitation in 1995 was 185 mm .(6) Thus, catastrophic fires in 2002 occurred due to the above-mentioned low precipitation conditions. Lightning may ignite fires in July because several fires occurred at almost the same time and at some distance from populated areas.
The purpose of this study is to evaluate available fire demand that can be guaranteed in the small-scale block distribution system in the commercial area by analyzing the several types of the small-scale block model. As a result, I came to the following conclusions. (1) Even in case of small-scale blocks four hydrants can be guaranteed to open simultaneously at its maximum by 150 mm pipelines ,which is regulated by The Standard of Fire Demand , or by the standard condition that is under head loss of 5m. (2) Five fire hydrants are guaranteed in the small-scale blocks, which have the scale of 5,000m3/day or over, by the standard condition that is under head loss of 5m.
To investigate the behavior of a sodium leakage fire and evaluate the fire risk, it is necessary to estimate quantitatively the sodium peroxide content in the sodium combustion residue. As the physical and chemical properties of sodium combustion residue are considerably different from the sodium peroxide reagent, it is necessary to verify whether a general method of the quantitative analysis intended for the sodium peroxide reagent is applicable to the analysis of the sodium combustion residue. For this purpose, we first analyzed the sodium peroxide reagent and sodium combustion residue generated under different atmosphere conditions using the potassium permanganate oxidation-reduction titration method and hydrolysis method respectively, and compared the obtained results. Next, we examined whether the oxygen generated from the sample was completely detected in the analysis process of each analysis method. Further, we investigated the cause of the incomplete detection of the generated oxygen in the analysis process of the combustion residue by the potassium permanganate oxidation-reduction titration method established in JIS K8231. From these results, we conclude that JIS K8231 is an improper method to the analysis of the sodium combustion residue and propose the application of the hydrolysis method with the analysis of the residual liquid to the analysis of the sodium combustion residue.
A new type detector tube for light mineral oils was developed for a field test at fire-scenes. The mixture of iodine pentoxide, sulfuric acid and silica gel was enclosed in a glass tube. The reagent in it was colored by reacting with volatile aromatic components contained in oils. The colors of the detector tubes were clearly different among oils. Light mineral oils were discriminated more easily with this new detector tube than the old one.
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