A new technique for generating heavy metal fumes with high melting point.
There are many kinds of fumes containing heavy metals in the working area. They sometimes have bad effects on the living body. It is important to determine their particle size distribution for considering the effects of those metals on health, together with measuring their amounts. For this purpose, it is neces-sary to generate fumes which are suitable to use. However, effective methods for generating fumes of heavy metals with high melting points have not been developed.In this study we attempted to determine whether the plasma flame metal sprayer can be used as a fume generator. The size distribution, particle form and amounts of the generated fumes were determined for the iron fume which were generated with this instrument under the various conditions. The fume was to consist of coagulated fine particles and dispersed globular particles. Our attempt extended to the generation of fumes consisting not only of one kind of metal but also of two kinds of metal. It was also found that fumes having the required radio might be generated by controlling the ratio of the metals in the powder mixture.We conclude that this instrument might be suitable for generating fumes of heavy metals in the laboratory.
TOXICITY OF INHALED METALLIC CADMIUM FUMES IN RATS
The injury by cadmium fumes of high concentrations to the lung after single exposure is most important in industrial poisoning. However, the experiment of inhalation is very difficult because there has been no technique to generate particle size as designed and to maintain a constant concentration of the metal fumes. At a new technique was developed by the authors, this experiment was performed to study the harmful effect on rats, having cadmium fumes (0.2 ƒÊ of particle size) inhaled for 30 minutes at various concentrations. The LC50 of the inhaled metallic cadmium fumes was 25 mg/m3 for rats. The retention rate of cadmium fumes in the lung was 15% after the exposure to the concentration at 20 mg/m3 for 30 minutes. The macro-findings of the lung after inhalation were characterized by the congestion and the edema. Cadmium retained in the lung showed very slow clearance and appreciable amounts of cadmium were found in other organs on the first day after exposure.
Observations of nearshore infragravity waves: Seaward and shoreward propagating components
[1] The variation of seaward and shoreward infragravity energy fluxes across the shoaling and surf zones of a gently sloping sandy beach is estimated from field observations and related to forcing by groups of sea and swell, dissipation, and shoreline reflection. Data from collocated pressure and velocity sensors deployed between 1 and 6 m water depth are combined, using the assumption of cross-shore propagation, to decompose the infragravity wave field into shoreward and seaward propagating components. Seaward of the surf zone, shoreward propagating infragravity waves are amplified by nonlinear interactions with groups of sea and swell, and the shoreward infragravity energy flux increases in the onshore direction. In the surf zone, nonlinear phase coupling between infragravity waves and groups of sea and swell decreases, as does the shoreward infragravity energy flux, consistent with the cessation of nonlinear forcing and the increased importance of infragravity wave dissipation. Seaward propagating infragravity waves are not phase coupled to incident wave groups, and their energy levels suggest strong infragravity wave reflection near the shoreline. The cross-shore variation of the seaward energy flux is weaker than that of the shoreward flux, resulting in cross-shore variation of the squared infragravity reflection coefficient (ratio of seaward to shoreward energy flux) between about 0.4 and 1.5.