We investigate whether a single population of first stars could have influenced both the metal enrichment and reionization of the high-redshift intergalactic medium (IGM), by calculating the generated ionizing radiation per unit metal yield as a function of the metallicity of stellar populations. We examine the relation between the ionizing radiation and carbon created by the first stars, since...

Hydrogen enrichment induced by pipeline welding residual stress is a key issue affecting the safe service of hydrogen pipelines. In order to explore influence on diffusion and effect heat treatment, an X80 model with six-layer girth weld was established using ABAQUS software, coupling analysis temperature field, carried out. The distribution in area local inclusion analyzed, relationship betwee...

Liquid-to-gas mass transfer in anaerobic processes was investigated theoretically and experimentally. By using the classical definition of k(L)a, the global volumetric mass transfer coefficient, theoretical development of mass balances in such processes demonstrates that the mass transfer of highly soluble gases is not limited in the usual conditions occurring in anaerobic fermentors (low-inten...

The preferential escape of the lighter isotope of hydrogen controls the global (D/H)H2O abundance ratio and comparison of the present abundance ratio with escape models provides an estimate of the amount of water lost over time. Earlier measurements reported a global atmospheric enrichment (D/H) of five times the mean terrestrial ocean value (VSMOW). Because of HDO and H2O different vapor press...

Hydrogen sulfide exists mostly as a detrimental byproduct in the gas processing units well refineries, and it must be eliminated from natural streams. In Sulfur Recovery Unit (SRU), hydrogen is converted into elemental sulfur during modified Claus process. Efficiency of recovery significantly depends on reaction furnace temperature. this work, effect oxygen acid enrichment temperature according...

The molecular origin of the isotope-induced diastereomeric enrichment in helical supramolecular polymers consisting of trialkylbenzene-1,3,5-tricarboxamides (BTAs) is studied using plane-wave DFT calculations. We demonstrate that the creation of a chiral center at the α-position of the alkyl chains of a BTA by H-D exchange leads to a small but notable preference for the formation of supramolecu...

Structure-based virtual screening (SBVS) protocols were developed to find cyclooxygenase-2 (COX-2) inhibitors using the Protein-Ligand ANT System (PLANTS) docking software. The directory of useful decoys (DUD) dataset for COX-2 was used to retrospectively validate the protocols; the DUD consists of 426 known inhibitors in 13289 decoys. Based on criteria used in the article describing DUD datase...

Introduction Because of a systematic enrichment in deuterium, the insoluble organic molecules (IOM) of the carbonaceous meteorites are generally considered to represent interstellar materials. However, since the D/H ratios in IOM remain much lower than those measured astronomically for organic molecules synthesized in the interstellar medium (ISM), no plausible process has been proposed to acco...