OBJECTIVES To review the published literature on respirable quartz exposure and associated disease in agricultural related settings systematically and to describe personal respirable dust and quartz measurements collected on a sandy soil farm in the Free State province of South Africa. METHODS The published studies on exposure to respirable silica and quartz in agriculture and related setting...

The grade of a quartz ore is not a measure of its chemical reactivity. A high grade quartz sample (B) showed low reactivity in sodium silicate production. Structural imperfection usually occurs due to lattice defects in the quartz tetrahedron as a result of several substitutions that happen during mineralization. The random distortion of the quartz tetrahedron that could be affected by various ...

We have developed a QCM (Quartz Crystal Microbalance) based method for direct gravimetric determination of water adsorption on PuO2 surrogate surfaces, especially CeO2, under conditions representative of those in a typical PuO2 storage can. In this application, the method of transduction of the QCM relies upon the linear relationship between the resonant frequency of piezoelectrically active qu...

High-density arrays of perfectly aligned single-walled carbon nanotubes (SWNTs) consisting almost exclusively of semiconducting nanotubes were grown on ST-cut single crystal quartz substrates. Raman spectroscopy together with electrical measurements of field effect transistors (FETs) fabricated from the as-grown samples showed that over 95% of the nanotubes in the arrays are semiconducting. The...

The first applications of acoustic devices to chemical detection were proposed by Sauerbray in 1959 [1]. For application in liquid media, mainly quartz microbalance (QCM) sensors have been investigated. Recent works on Love waves devices for gas detection have demonstrated definitely their superiority, in particular in term of mass loading effect sensitivity [2]. As the shear horizontal polariz...

The Fuzzy c-Means (FCM) clustering models were used for the discrimination of organic compounds using piezoelectric chemical sensor array data of 14 analytes. Appropriate clusters are found by the sum of the weighted quadratic distances between data points and cluster prototypes. A priori known information can be integrated into the clustering algorithm by using constrained prototypes. A sensor...

been compiled and analyzed to characterize current occupational expo~urcs to quartz: to determine if the quartz percentages of samples collected for different occupations have changed during the period 1985 through 1992; and to study the intranline variability associated \'vid1 quartz sample percentages of selected occupations. Analysis of the occupational data shows that regardless of the type...

Silica, or silicon dioxide (SiO2), is a group IV metal oxide, which naturally occurs in both crystalline and amorphous forms (i.e. polymorphic; NTP, 2005). The various forms of crystalline silica are: α-quartz, β-quartz, α-tridymite, β-tridymite, α-cristobalite, β-cristobalite, keatite, coesite, stishovite, and moganite (NIOSH, 2002). The most abundant form of silica is α-quartz, and the term q...

introduction arefi quartz-bearing conglomerate (middle jurassic) is situated within binalud structural zone. the unit is trending nw-se located 25 km south of mashhad. more than 97% of the pebbles are quartz as mono-crystalline, poly-crystalline, and minor fragments of chert, quartzite, and mica schist. less that 3% of the remaining minerals are feldspar, mica, chlorite, hornblende, tourmaline,...