An External Beam Method for Multi-Elemental Analysis of Heavy Metals in Stream Water

An improvement has been made on a liquid target preparation for an external proton beam PIXE which is regarded as an excellent technique for multi-elemental analysis. A 2 MeV proton beam taken out to the atmosphere through an exit Kapton foil bombards an acidic solution target directly. Such direct bombardment enables the direct comparison of X-ray yields of a liquid sample with those of the standard solution so that one can determine the elemental concentration in a liquid sample more precisely and easily. An example is given for the analysis of heavy metals in stream water

住宅における自然換気量及び大気浮遊粉塵濃度の測定(B. 生活科学)

We have measured CO_2 concentrations of the neighboring three rooms in a dwelling house simultaneously. The ventilation volumes of these rooms are deduced from the observed changes of CO_2 concentrations. By taking into account the effects of diffusion and flow on a ventilation, the observed changes of CO_2 concentrations are reproduced very well. At the same time, mass concentrations of airborne dust were also measured inside and outside of the dwelling house. The mass concentration ratio of airborne dust inside of the dwelling house to outside was ranging from 0.3 to 0.4,which agreed very well with our previous measurements. It was found that mass concentration of windward room was higher than that of downwind one. Such difference is interpreted qualitatively by the deduced air flow from the ventilation measurement

生活水の中の重金属 : 煮沸による鍋からの重金属(B. 生活科学)

With the aid of the external beam PIXE we have developed a method for analysis of heavy metals in the water boiled with a pan. It was shown that this method could successfully determine the concentration of nickel in the water boiled with a pan of aluminium

住宅の内外における大気浮遊粉塵の季節変化(B. 生活科学)

Mass and elemental concentrations of airborne dust inside and outside of a dwelling house were measured at four seasons over a year. The airborne dust samples were collected by using low volume air samplers and the elemental concentration was determined by INAA method. The mass concentration varied remarkably over a year. On the other hand, it was found that the shielding factor (mass ratio of the outside to the inside) does not change. The elemental concentration showed same trend to the mass one. The shielding factor for individual element, however, was classified into two groups according to the size distribution of dust particles. These results indicate that the shielding function of a dwelling house depends mainly on the dust particle size. To obtain a correlation between wind and mass concentration, simultaneous measurments were carried out employing a computerised wind vane and an anemometer, as well as a piezobalance dust meter

風船法による住宅の自然換気量の測定(B. 生活科学)

Natural ventilation of a dwelling house has been measured by using CO_2 gas method. To avoid an increase of the atmospheric pressure of the room, a balloon which was filled with CO_2 gas under the same pressure was employed as a CO_2 gas source. The measurement was carried out with a remote control system. The measured decrease of the CO_2 gas concentration was reproduced by sum of two exponential components and constant background level, which indicates that the ventilation of the room is affected at least by three states including the relevant room, surrounding atmosphere and the neighbouring room. We applied two room model, i.e. three states model instead of simple one room model, to analyse the observed decay of CO_2 gas concentration