-A vermiculite (Libby, Montana) sample obtained from the Zonolite company contained mostly coarse-grained separates with only 8.7 per cent clay. The 2-50 #m fraction was used for particle-size reduction studies by wet and dry grinding, and size-fractionated into < 2, 2-5, 5-20 and 20--50 #m sizes. About 18 per cent of the sample was attrited to clay after 64 hr of wet grinding, but as much as 5...

Rifamycins are broad spectrum and important antibiotics used in the treatment of pathogenic diseases. They are generally produced by the fermentative cultivation of Amycolatopsis mediterranei, using submerged cultivation system. The medium composition greatly influences the antibiotic production. Trace elements are one of the major factors need to be optimized to enhance the production of rifam...

INTRODUCTION We compared feces culturing in charcoal or vermiculite to obtain Strongyloides venezuelensis larvae. METHODS Feces (5 g) from infected rats was mixed with vermiculite (10 g) or coal (10 g) in plastic cups and incubated at 28°C for 48 h. Larvae were recovered using Baermann-Moraes method. RESULTS Significantly higher number of positive larval cultures were recovered from vermicu...

BACKGROUND Libby, Montana, was home to the largest vermiculite ore mine in the United States. The processing, use, and transport of the ore, which was contaminated with amphibole asbestos, led to generalized contamination of the community. The mine closed in 1990. OBJECTIVES We examined the prevalence of respiratory symptoms in 2000-2001 and their association with history of vermiculite expos...

The effect of orientation of vermiculite particles on the diffusion of Na ion was measured by a tracer technique. The diffusion measurements were made on pellets prepared by pressing freezedried vermiculite in a cylindrical die and the diffusion coefficient evaluated by a thin-film boundary condition of Fick's law. Because flakes of vermiculite were highly oriented under the pressing force, it ...

-The alteration experiments of phlogopite with 0.01 N HC1 solution containing 0.1 M NaC1 at 50*, 80* and 120"C have been carried out to aid in the understanding of the dissolution process of mica and the formation of secondary phases such as vermiculite and interstratified mica/vermiculite. Twenty milligrams of phlogopite samples were suspended in 20 ml or 100 ml of leaching solution. In these ...

Four different composite mixtures with varying amounts of expanded vermiculite were exposed to high temperatures of 300, 600, 900 and 1100uC for 6 h. Physical and mechanical properties including unit weight, porosity, water absorption, residual compressive strength, residual splitting tensile strength and also ultrasonic pulse velocity were determined after air cooling. Microstructures were inv...

Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs+ ...

Poly(L-lactic acid)-co-bisphenol-A epoxy resin/vermiculite nanocomposites (PLLA–co-bis A ER/VMT) were prepared by in situ melt polycondensation of L-LA in the presence of amino-modified vermiculite. The fourier transform infrared (FTIR) spectra was used to investigate molecular interactions between the modified vermiculite and PLLA. Transmission electron microscopy (TEM) testing indicated that ...

OBJECTIVES To describe asbestos-related mortality among manufacturing workers who expanded and processed Libby vermiculite that contained amphibole fiber. METHODS Standardized mortality ratio was calculated for 465 white male workers 31 years after last Libby vermiculite exposure. RESULTS Two workers died from mesothelioma, resulting in a significantly increased standardized mortality ratio...