The objective of this study was to evaluate the marginal and internal fit of zirconia copings obtained with different digital scanning methods. A human mandibular first molar was set in a typodont with its adjacent and antagonist teeth and prepared for an all-ceramic crown. Digital impressions were made using an intraoral scanner (3Shape). Polyvinyl siloxane impressions and Type IV gypsum model...

The isotopic composition of water in hydrated minerals, such as gypsum and jarosite, has numerous applications in studies of recent climate change, ore formation, and soil development. However, oxygen and hydrogen isotope analysis of water of crystallization is currently a complex procedure. Commonly used techniques involve offline extraction of water from hydrated minerals and subsequent isoto...

to measure soil water content (or soil matric suction) in thin layers of about 30mm, conventional gypsum blocks are not suitable. to carry out the task, mini-gypsum blocks were constructed using plaster of paris in an innovative fashion. a power relationship was found between the soil water content and the mini-gypsum blocks’ readings in kω. the calibration results showed that readings of m...

Irrigation-induced salinization is an important land degradation process that affects crop yield in the Brazilian semi-arid region, and gypsum has been used as a corrective measure for saline soils. Fluvent soil samples (180) were treated with increasing levels of salinization of NaCl, MgCl2 and CaCl2. The salinity was gauged using electrical conductivity (EC). Gypsum was added to one split of ...

Inorganic carbonate in soil occurs predominantly as the sparingly soluble alkaline-earth carbonates, calcite (CaCOs) and dolomite (CaMg(CO,),). Calcite is usually the dominant form in active pedogenic environments (Doner & Lynn, 1977; Nelson, 1982). There are only a few reported occurrences of aragonite (CaCOs) and vaterite (CaCOs) in soils. Sodium carbonate and magnesium carbonate and hydroxyc...

The effectiveness of magnesium as a substitute material in enzyme-mediated calcite precipitation was evaluated. Magnesium sulfate was added to the injecting solution composed of urea, urease, and calcium chloride. The effect of the substitution on the amount of precipitated materials was evaluated through precipitation tests. X-ray powder diffraction and scanning electron microscopy analyses we...

The experiment was conducted on farmer’s field at District Lakki Marwat (NWFP) during Rabi (spring) 2007-08, in order to study the response of wheat to different soil treatments irrigated with poor quality irrigation water. The treatments including control, tillage, gypsum and sulphuric acid were applied before sowing of the wheat crop. The treatments were arranged in a randomized complete bloc...

gypsum found in the soil beneath the foundation of structures, specially hydraulic structures, can cause serious damage to them. the mechanical behavior of gypsiferous soils has not so far been investigated in detail except for the works of petrukhin (1993). here, it has been tried to investigate the mechanical behavior and the effect of soil being leached on settlement and strength of these ki...