Both iron(II) and (III) form complexes in aqueous thiocyanate solutions 1,2 , and solvent extraction of these metal ions from the solutions is possible with different types of extractants.3 The solvent extraction of iron(III) has been studied with neutral extractants, such as ethers, ketones, alcohols and tributylphosphate, and also with cationic extractants, such as quaternary ammonium ions.3-8 However, the solvent extraction of iron(II) from thiocyanate solutions has not been studied very much. In the present work, the solvent extraction of iron(II) and (III) as anionic thiocyanate complexes with tetrabutylammonium ions into chloroform was studied and the equilibria among the chemical species were estimated by a statistical analysis of the data. The difference in the formation and extraction behaviors of the thiocyanate complexes in these oxidation states was considered by comparing the stability and extractability of the complexes in aqueous solutions.
A remarkable, large 5re occurred in a 20 stories high-rise apartments in 1996 in Hiroshima City. The 5re spread from the 5re origin apartment unit on the 9th 6oor up to the top 20th 6oor, very quickly by external 6ame spread through balconies. The authors investigated the evacuation behaviour of the occupants including reaction to 5re cues, motives for starting evacuation, and choice of evacuation route by means of questionnaire survey and also peer interviews with some of them, focusing on the use of elevators in evacuation by 6oor height and/or age group in this very rare 5re incident. From the investigation, the following results were obtained.(1) Probably due to the experience of many past small 5res, there was a time lag between the perception of 5re and starting the evacuation. Many respondents started their evacuation on the directions of others, not by direct 5re cues such as smoke. Also, the reaction of occupants after the perception of 5re is a4ected by their perception of the seriousness of the 5re.(2) The likelihood of elevator use in evacuation is mainly related to the 6oor height in which the occupants live, but is not so closely related to the age of the occupants. The proportion of elevator use in evacuation grows dramactically from the 10th to 13th 6oor.(3) People are likely to choose 9the route they usually use: or 9a safer route: rather than 9a closer route:.
The solvent extraction of silver(I) in aqueous 0.1 mol dm-3 sodium nitrate solutions with 2-thenoyltrifluoroacetone (Htta) and 4-isopropyltropolone (f3-isopropyltropolone, Hipt) into chloroform was studied in the absence and presence of tetrabutylammonium ions (tba+), and the results were compared. Although extraction with Htta was poor, it was very much enhanced and nearly quantitative extraction was achieved by the addition of tba+. This was assumed to be due to the fact that the complex, Ag(tta), was hydrophilic due to its hydration, but tba+Ag(tta)2-, which was extracted in the presence of tba+, was very weakly hydrated and bulkier. Both Ag(ipt) and Ag(ipt)(Hipt) were extracted; extraction with Hipt was not very effective in the absence of tba+. By the addition of tba+, the anionic complex, tba+Ag(ipt)2-, was also extracted, and nearly quantitative extraction was also achieved. Since the formation of this anionic complex is made by an exchange of ipt-with Hipt of the Ag(ipt)(Hipt) species, the enhancement of extraction was impaired by the dissociation of Hipt from the self-adduct.
In performance-based fire safety design of buildings, design fires are assumed based on relatively coarse information of potential combustible objects described by the object name, weight, size and constituent materials. The fire effect is calculated by using assumed design heat release rate (HRR) to judge appropriateness of fire safety provisions. For this purpose, a simple estimation method to estimate design HRR curve (full time history of HRR) was developed. The method is based on summary of available experimental datasets of various combustibles, which were categorized into groups by their names and constituent materials. As a nature of categorized groups, there are two types of variations of HRR characteristics within each category group. One type is that the object size is almost constant within each category group. For this type, HRR curves are simply averaged over the available datasets in order to obtain the characteristic design HRR curve. The method was applied to chairs and sofas. The other type is that the object size varies within each category group. To develop size-dependent HRR curves, rates of fire growth and decay were averaged over datasets in the group. Maximum HRR and total heat release (THR) were correlated with surface area and weight, respectively.The method was applied to Christmas trees. By using the proposed methods, it is possible to establish a simple formula to represent full HRR diagrams by their category names.
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