Aims. We investigate the purely thermal formation of hexamethylenetetramine (HMT, C6H12N4) in interstellar ice analogs from nonphotolysed ice and compare our results with those for the formation from photolysed ice. Methods. We use Fourier transform-infrared spectroscopy to follow residue formation from VUV irradiation of H2CO:NH3 ice mixture in different concentration ratios. We also report th...

Non-enzymatic oligomerization of activated ribonucleotides leads to ribonucleic acids that contain a mixture of 2',5'- and 3',5'-linkages, and overcoming this backbone heterogeneity has long been considered a major limitation to the prebiotic emergence of RNA. Herein, we demonstrate non-enzymatic chemistry that progressively converts 2',5'-linkages into 3',5'-linkages through iterative degradat...

A major computational code called CERV was developed to determine complex equilibrium compositions of a nonideal mixture of numerous imperfect gases and compressible liquid and solid species with phase transitions for closed-vessel applications. This code minimizes Gibbs energy using reaction variables, in contrast to other major codes like BRL-Blake, BRCBagheera and NASA-CEA that use compositi...

This paper examines the problem of distant microphone speech recognition in noisy indoor home environments. The noise background can be roughly characterised in terms of a slowly varying noise floor in which there are embedded a mixture of energetic but unpredictable acoustic events. Our solution to the problem combines two complementary techniques. First, a soft missing data mask is formed whi...

Metal/fluoropolymer composites represent a new category of energetic structural materials that release energy through exothermic chemical reactions initiated under shock loading conditions. This paper describes an experiment designed to study the reaction characteristics of energetic materials with low porosity under explosive loading. Three PTFE (polytetrafluoroethylene)/Ti/W mixtures with dif...

This article discusses the technology for doping hydrogen into fermenter to increase methane production and amount of energy in mixture. Hydrogen is anticipated enable more carbon be applied produce methane. proposed produced by using excess electricity from, example, off-peak hours at night. The possibilities a mixture biogas combustion boilers internal engines have been determined. It has pro...

This work presents a method for estimation of the acoustic intensity, the energy density and the associated sound field diffuseness around the origin, when the sound field is weighted with a spatial filter. The method permits energetic DOA estimation and sound field characterization focused in a specific angular region determined by the beam pattern of the spatial filter. The formulation of the...

Nanocomposite reactive microspheres with diameters of approximately 1-5 mum were created via electrostatic self-assembly of aluminum and cupric oxide nanoparticles. The ability to utilize this novel approach of bottom-up assembly to create these reactive materials allows for the potential for a more intimate mixture between the two nanoreactants and, thus, an overall more energetic combustion p...

Abstract. We study the energetic aspects of hybrid pressure-gravity modes pulsations. The case of hybrid β Cephei-SPB pulsators is considered with special attention. In addition to the already known sensitivity of the driving mechanism to the heavy elements mixture (mainly the iron abundance), we show that the characteristics of the propagation and evanescent regions play also a major role, det...