Acid–base thermochemistry of isolated amino acids containing oxygen or sulfur in their side chain (serine, threonine, cysteine and methionine) have been examined by quantum chemical computations. Density functional theory (DFT) was used, with B3LYP, B97-D and M06-2X functionals using the 6-31+G(d,p) basis set for geometry optimizations and the larger 6-311++G(3df,2p) basis set for energy comput...

Thioesters and thioacetic acid (TAA) have been invoked as key reagents for the origin of life as activated forms of acetate analogous to acetyl-CoA. These species could have served as high-energy group-transfer reagents and allowed carbon insertions to form higher molecular weight compounds such as pyruvate. The apparent antiquity of the Wood-Ljungdahl CO2 fixation pathway and its presence in o...

Sewage sludge is an unavoidable secondary pollution produced in the process of sewage treatment. At present traditional methods of treating sludge (e.g. landfill, incineration or land application) have some disadvantages and shortages. Direct thermochemical liquefaction of sludge is a new treatment method, which has the advantage of both treatment and energy recovery. Research progress and appl...

Sub-Neptunes (Rp~1.25-4 REarth) remain the most commonly detected exoplanets to date. However, it remains difficult for observations tell whether these intermediate-sized have surfaces and where their are located. Here we propose that abundances of trace species in visible atmospheres sub-Neptunes can be used as proxies determining existence approximate surface conditions. As an example, a stat...

The prediction of toxic emissions from industrial and warehouse fires and explosions involving reactive chemicals has eluded the hazard analysis community for quite some time. To address this issue, we developed a model called ADORA for the time evolution of toxic emissions and their dispersion in the atmosphere. At each time step, the conservation of mass, energy and momentum are solved while ...

Thermochemical cycles that split water into stoichiometric amounts of hydrogen and oxygen below 1,000 °C, and do not involve toxic or corrosive intermediates, are highly desirable because they can convert heat into chemical energy in the form of hydrogen. We report a manganese-based thermochemical cycle with a highest operating temperature of 850 °C that is completely recyclable and does not in...

To determine how active volcanism might affect the standard picture of sulfur dioxide photochemistry on Io, we have developed a one-dimensional atmospheric model in which a variety of sulfur-, oxygen-, sodium-, potassium-, and chlorine-bearing volatiles are volcanically outgassed at Io’s surface and then evolve due to photolysis, chemical kinetics, and diffusion. Thermochemical equilibrium calc...

and the chemical weathering of primary minerals to secondary minerals (i.e., soil) on the surface. Physical properWe present a comprehensive study of the redox state of the lower atmosphere and surface of Venus. This study constrains ties such as the spectral reflectance, dielectric constant, the CO concentration and oxygen fugacity at the surface of electrical conductivity, magnetic susceptibi...

The preparation and full characterization of the 4-(nitrophenyl)phenoxyl radical, 2,6-di-(t)butyl-4-(4'-nitrophenyl) phenoxyl radical ((t)Bu2NPArO(•)) is described. This is a rare example of an isolable and crystallographically characterized phenoxyl radical and is the only example in which the parent phenol is also crystallographically well-defined. Analysis of EPR spectra indicates some spin ...