Physical and mechanical properties of waste ground at inert waste landfills.

The physical and mechanical properties of waste ground were examined at 14 locations across 4 inert waste landfills in Japan with the goal of establishing a safe and cost-effective design methodology specific to inert waste landfills. Composition analysis, basic physical properties, angle of repose, CASPOL impact value tests, and in situ direct shear tests were conducted. Inert wastes were comprised of three main components: fibrous, granular, and soil-like content, and their compositions varied between 3.6-54%, 13-45%, and 43-74%, respectively. As the fibrous content and age after reclamation increased, the water content increased but the percentage air voids decreased. The impact value (Ia), which is an indicator of the bearing capacity, increased as the dry density increased. For all locations, the angle of repose after avalanche (αa) was found between 34 and 44°. In direct shear tests, the cohesion (c) and internal angle of friction (φ) ranged from 2 to 21 kN/m2 and 22-59°, respectively. The shear stresses obtained from these c and φ values were higher than those for the municipal solid wastes, particularly for landfills with fibrous fractions ranging 14-31% under a normal stress of 25.55 kN/m2. c increased and φ decreased as the dry density increased. The correlation calculated for c and φ with Ia for inert waste landfill were c = 4.10Ia - 21.32 and φ = -4.61Ia + 82.37. Finally, the utilization of the results obtained in this study is discussed in three design stages: planning, landfilling, and future expansion.

Preliminary study of a challenge test to the patients with Japanese cedar pollinosis using an environmental exposure unit.

OBJECTIVE: Although clinical studies on pollinosis have been performed employing placebo-controlled double-blind comparative and field techniques, accurate evaluation is difficult because the scattering pollen count and climatic conditions vary between years and regions, leading to a bias in the results. Thus, we prepared a pollen challenge test unit (allergen challenge chamber: ACC) which facilitates quantitative pollen challenge at any time, and, so, the acquisition of objective data. METHODS: The control of constant conditions and maintenance of specified pollen concentrations in ACC were investigated. In addition, the pollen distribution in ACC was measured while maintaining the level at 10,000 counts/m(3). The pollen levels were measured employing the aspiration and Durham methods, and the measured values were compared. Furthermore, whether symptoms are adequately induced in the chamber during the non-cedar pollen-scattering season was investigated in 14 volunteers with cedar pollinosis. RESULTS: When the pollen level in ACC was set at 6000 counts/m(3) or higher, the rate of variation was +/-15%, within the adjustable range, and that of the pollen distribution in the chamber was within +/-20%. When the volunteers with cedar pollinosis were exposed to cedar pollen in ACC, pollinosis symptoms were induced, and challenge for 2 consecutive days significantly induced symptoms. CONCLUSIONS: The temporal and spatial variations of the pollen level in ACC were small, facilitating stable pollen challenge, and pollinosis symptoms were induced in the volunteers with cedar pollinosis. The challenge chamber may be useful to judge the effects of therapy against pollinosis.