Introduction: Carbonates have been recently detected in dust shells of evolved stars [1] and protostars [2,3] suggesting that they could form under dry conditions (without liquid water). Around young stars, silicates are mainly magnesium-rich, amorphous and porous dusts [4], believed to form in the interstellar medium (ISM) by irradiation [5]. Such material is far from equilibrium and potential...

The organocatalytic synthesis of substituted vinylene carbonates from benzoins and acyloins was studied using diphenyl carbonate as a carbonyl source. A range N-Heterocyclic Carbene (NHC) precursors were screened it found that imidazolium salts the most active for this transformation. reaction occurs at 90 °C under solvent-free conditions. wide (symmetrical unsymmetrical, aromatic or aliphatic)...

Facies modeling is an essential part of reservoir characterization. The connectivity of facies model is very critical for the dynamic modeling of reservoirs. Carbonate reservoirs are so heterogeneous that variogram-based methods like sequential indicator simulation are not very useful for facies modeling. In this paper, multiple point geostatistics (MPS) is used for facies modeling in one of th...

Travertine deposits are a kind of continental carbonates that form in specific chemical, physical and biological conditions. Garab travertines in southeast of Mashhad are studied based on field, geochemistry (elemental and stable isotope analysis) and hydro-geochemistry analysis. Field and petrographic characterization led to recognize of crystalline crust, raft, foam, shrub, laminated, black m...