Fluidized-bed biological reactors (FBBRs) may be used to remove chloroethenes such as trichloroethene (TCE) from groundwater. Proper selection of FBBR aqueous growth medium, biofilm solid support media type and size, and bed charge (bed depth to column length fraction) are critical for establishing a biomass of sufficient quantity and activity to transform TCE via aerobic cometabolism, which re...

The two well known techniques which are used in plant-nutrition studies are conveniently designated the solution-culture method and the sand-culture method. Some other slightly soluble materials, such as cinders, gravel, vermiculite, and Sponge Rok or various combinations of these may be substituted for sand. The use of slightly soluble material as a medium, to which the nutrient solution is pr...

Devonian black shales that were deposited on the North American craton contain abundant Tasmanites cysts. Although these are typically flattened because of compaction, a small proportion of cysts is filled with diagenetic silica. The latter are spherical to ellipsoidal (0.1-0.5mm), and filled with chalcedony, microand megaquartz, and with single quartz crystals. Chalcedonic cyst fillings are pr...

Abstract Detrital coesite-bearing garnet is the final product of a complex geological cycle including coesite entrapment at ultra-high-pressure conditions, exhumation to Earth’s surface, erosion and sedimentary transport. In contrast usual enrichment high-grade metamorphic in medium- coarse-sand fractions, grains are often enriched very-fine-sand fraction. To understand this imbalance, we analy...

In moulding of large-size castings, the lack of uniformity in heating results in the deformation of individual mould parts. The resulting deformations cause internal stre-sses in the casting and scabbing in the mould. The main cause of deformation in the mould element is to be found in the α β transformation of the quartz grains. The allotropic modification of the quartz crystals from α into β ...

Endoliths in sandstones: Many scenarios for the colonization of planetary surfaces by microbial life involve endoliths [1, 2]. The need to avoid the damaging effects of ultraviolet radiation makes colonization of the immediate sub-surface desirable, particularly at an early stage of evolution before screening pigments have been developed [3, 4]. Minimal (millimetreto sub-millimetre-scale) penet...

and Vagners (1971, 1972) expressed this phenomenon elegantly by introducing the concept of "terminal mode" for the optimum grain size to which a mineral can be reduced, given the force and energy typically available in the glacial environment. Thus, hard, uncleaved or poorly cleaved minerals such as quartz, fcldspar, garnet, pyrite and magnetite dominate either the medium or the fine sand fract...

The filling of thin-walled steel tubes with quartz sand can help to prevent the premature buckling of the steel tube at a low cost. During an impact, the internal stress of the quartz sand-filled steel tube column is subjected to not only axial force but also lateral confining force, resulting in complicated internal stress. A suitable sensor for monitoring the internal stress of such a structu...

-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 ...