When cracks form in a thin contracting layer, they sequentially break the layer into smaller and smaller pieces. A rectilinear crack pattern encodes information about the order of crack formation, as later cracks tend to intersect with earlier cracks at right angles. In a hexagonal pattern, in contrast, the angles between all cracks at a vertex are near 120 degrees. Hexagonal crack patterns are...

Gypsum soils are among the most restrictive and widespread substrates for plant life. Plants living on gypsum are classified as gypsophiles (exclusive to gypsum) and gypsovags (non-exclusive to gypsum). The former have been separated into wide and narrow gypsophiles, each with a putative different ecological strategy. Mechanisms displayed by gypsum plants to compete and survive on gypsum are st...

Dental plaster is one of these products that mainly used to produce dental casts and mounting purposes. Although the cost very low, their inferior compressive strength, low abrasion resistance dimensional instability restricted usage as primary working casts. The inclusion different fillers in gypsum could play an important role improving performance. Aim: aim this study was evaluate physical p...

BACKGROUND AND AIMS Plants from gypsum habitats are classified as gypsophiles and gypsovags. The former include both narrow endemics limited to small gypsum areas and regionally dominant gypsophiles growing in gypsum areas of large regions, whereas gypsovags are plants that can grow both in gypsum and non-gypsum soils. Factors controlling the distribution of gypsum plants are still not fully un...

An original and detailed study focusing the petrography of evaporites from the Late Aptian deposits exposed in the eastern and southern São Luís-Grajaú Basin is presented herein, with the attempt of distinguishing between primary and secondary evaporites, and reconstructing their post-depositional evolution. Seven evaporites phases were recognized: 1. chevron gypsum; 2. nodular to lensoidal gyp...

Among other factors, the precision of dental impressions is an important and determining factor for the fit of dental restorations. The aim of this study was to examine the three-dimensional (3D) precision of gypsum dies made using a range of impression techniques and materials. Ten impressions of a steel canine were fabricated for each of the 24 material-method-combinations and poured with typ...

Background Gypsum, or calcium sulfate dihydrate, (CaSO4 l 2H2O) is the major component of drywall, or gypsum board, core. It is a naturally occurring mineral, deposited largely as a result of the evaporation of water in ancient inland seas, which contained large amounts of dissolved gypsum. For example, the evaporation of a typical 20,000 gallon residential swimming pool filled with seawater wi...

Mineral trioxide aggregate (MTA) cement is widely used in the field of endodontic treatment. We herein synthesized calcium silicates from carbonate and silicon dioxide, with aim reducing cost associated MTA. Additionally, we prepared gypsum-containing silicate to reduce setting time while enhancing mechanical strength. evaluated physical properties this investigated response human dental pulp s...

The rate of hydration influences many important physical properties of gypsum. Previous research examined the rate of gypsum hydration and related this to compressive strength and microstructure development using BET specific surface area analysis. The analysis of gypsum porosity in combination with BET surface area and rate of hydration remains to be done. In the present study, mesoporosity is...