SEM, EDS and vibrational spectroscopic study of the sulphate mineral rostite AlSO₄(OH,F)·5(H₂O).

We have studied the mineral rostite, a sulphate mineral of aluminium of formula AlSO4(OH,F)·5(H2O). The mineral is formed in mine dumps and wastes. Chemical analysis proves the presence of Al, F and S.

Vibrational spectroscopic study of poldervaartite CaCa[SiO3(OH)(OH)].

We have studied the mineral poldervaartite CaCa[SiO3(OH)(OH)] which forms a series with its manganese analogue olmiite CaMn[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis, Raman and infrared spectroscopy. Chemical analysis shows the mineral is reasonably pure and contains only calcium and manganese with low amounts of Al and F. Thermogravimetric analysis proves the mineral decomposes at 485°C with a mass loss of 7.

The molecular structure of the borate mineral inderite Mg(H4B3O7)(OH) · 5H2O--a vibrational spectroscopic study.

We have undertaken a study of the mineral inderite Mg(H4B3O7)(OH) · 5H2O a hydrated hydroxy borate mineral of magnesium using scanning electron microscopy, thermogravimetry and vibrational spectroscopic techniques. The structure consists of [Formula: see text] soroborate groups and Mg(OH)2(H2O)4 octahedra interconnected into discrete molecules by the sharing of two OH groups. Thermogravimetry shows a mass loss of 47.

Thermal analysis and vibrational spectroscopic characterization of the boro silicate mineral datolite - CaBSiO4(OH).

The objective of this work is to determine the thermal stability and vibrational spectra of datolite CaBSiO4(OH) and relate these properties to the structure of the mineral. The thermal analysis of datolite shows a mass loss of 5.83% over a 700-775°C temperature range.

Vibrational spectroscopy of the phosphate mineral kovdorskite-Mg2PO4(OH)·3H2O.

The mineral kovdorskite Mg2PO4(OH)·3H2O was studied by electron microscopy, thermal analysis and vibrational spectroscopy. A comparison of the vibrational spectroscopy of kovdorskite is made with other magnesium bearing phosphate minerals and compounds. Electron probe analysis proves the mineral is very pure.

Characterization of the sulphate mineral amarantite - Fe2(3+)(SO4)O·7H2O using infrared, Raman spectroscopy and thermogravimetry.

The mineral amarantite Fe2(3+)(SO4)O·7H2O has been studied using a combination of techniques including thermogravimetry, electron probe analyses and vibrational spectroscopy. Thermal analysis shows decomposition steps at 77.63, 192.

Vibrational spectroscopy of the mineral meyerhofferite CaB3O3(OH)5·H2O--an assessment of the molecular structure.

Meyerhofferite is a calcium hydrated borate mineral with ideal formula: CaB3O3(OH)5·H2O and occurs as white complex acicular to crude crystals with length up to ~4 cm, in fibrous divergent, radiating aggregates or reticulated and is often found in sedimentary or lake-bed borate deposits. The Raman spectrum of meyerhofferite is dominated by intense sharp band at 880 cm(-1) assigned to the symmetric stretching mode of trigonal boron. Broad Raman bands at 1046, 1110, 1135 and 1201 cm(-1) are attributed to BOH in-plane bending modes.

Mine water treatment with limestone for sulfate removal.

Limestone can be an option for sulfate sorption, particularly from neutral mine drainages because calcium ions on the solid surface can bind sulfate ions. This work investigated sulfate removal from mine waters through sorption on limestone. Continuous stirred-tank experiments reduced the sulfate concentration from 588.

Edentulism and shortened dental arch in Brazilian elderly from the National Survey of Oral Health 2003.

Objective: To describe the distribution of edentulism and estimate the prevalence of functional dentition and shortened dental arch among elderly population.

Methods: A population-based epidemiological study was carried out with a sample of 5,349 respondents aged 65 to 74 years obtained from the 2002 and 2003 Brazilian Ministry of Health/Division of Oral Health survey database. The following variables were studied: gender; macroregion of residence; missing teeth; percentage that met the World Health Organization goal for oral health in the age group 65 to 74 years (50% having at least 20 natural teeth); presence of shortened dental arch; number of posterior occluding pairs of teeth.

HIV/AIDS risk among female sex workers who use crack in Southern Brazil.

Objective: To understand the social context of female sex workers who use crack and its impact on HIV/AIDS risk behaviors. METHODODOLOGICAL PROCEDURES: Qualitative study carried out in Foz do Iguaçu, Southern Brazil, in 2003. Twenty-six in-depth interviews and two focus groups were carried out with female commercial sex workers who frequently use crack.