Solid–liquid phase equilibria for binary mixtures of propellant’s stabilizers

Solid–liquid equilibria for three binary mixtures of N-(2-acetoxyethyl)-p-nitroaniline (1) + 2-nitrodiphenylamine (2), N-(2-acetoxyethyl)-p-nitroaniline (1) + ethyl centralite (2) and N-(2-acetoxyethyl)-p-nitroaniline (1) + methyl centralite (2) have been determined experimentally using differential scanning calorimeter (DSC). Simple eutectic behaviours for these systems have been observed. The experimental results have been correlated by means of NRTL and UNIQUAC equations. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.61 to 3.32 K and depend on the particular model used. The best solubility correlation has been obtained with the UNIQUAC model.     

Experimental determination and prediction of (solid + liquid) phase equilibria for binary mixtures of heavy alkanes and fatty acids methyl esters

Solid–liquid equilibria for three binary mixtures of {n-eicosane (1) + methyl palmitate (2)}, {n-tetracosane (1) + methyl stearate (2)} and {n-octacosane (1) + methyl stearate (2)} were measured using differential scanning calorimeter. Simple eutectic behaviours for these systems were observed. The experimental results were correlated by means of the modified UNIFAC (Larsen and Gmehling versions), UNIQUAC and ideal models. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.21 K (for UNIQUAC model) to 1.07 K (for Ideal model) and depend on the particular model used. The best solubility correlation was obtained with UNIQUAC model.     

High precision measurement of the superallowed 0+ --> 0+ beta decay of 22Mg

The half-life, 3.8755(12) s, and superallowed branching ratio, 0.5315(12), for 22Mg beta decay have been measured with high precision. The latter depended on gamma-ray intensities being measured with an HPGe detector calibrated for relative efficiencies to an unprecedented 0.15%. Previous precise measurements of 0+ --> 0+ transitions have been restricted to the nine that populate stable daughter nuclei. No more such cases exist, and any improvement in a critical Cabibbo-Kobayashi-Maskawa unitarity test must depend on precise measurements of more exotic nuclei. With this branching-ratio measurement, we show those to be possible for T(z)=-1 parents. We obtain a corrected Ft value of 3071(9) s, in good agreement with expectations.     

Asymptotic Normalization Constants in Nuclear Astrophysics

The indirect method of determining astrophysical nuclear reaction rates is discussed. The overall normalization of the astrophysical S-factor for such reactions may be determined from one quantity, the asymptotic normalization coefficient of the overlap function of the bound state wave functions for the initial and final channels. These coefficients can be found also from peripheral transfer reactions whose amplitudes are determined by the same overlap function as the amplitudes of the corresponding astrophysical radiative capture processes. The experimental test of this approach and the last results of S₁₇ measurements are presented.     

First observation of F

We measured the excitation function for ¹³O + p elastic scattering to obtain data on the unknown ¹⁴F nucleus. The ground state and several low-lying excited states in ¹⁴F were observed and spin/parity assignments were made. ¹⁴F appears to be much less unstable than was predicted. We compare theoretical predictions for the ¹⁴F level scheme with the experimental results.     

Weighted product Hardy space associated with operators

Assuming that the operators L₁, L₂ are self-adjoint and {\mathrm{e}}^{-{{\displaystyle tL}}_i}(i=\mathrm{1},\mathrm{2}) satisfy the generalized Davies-Gaffney estimates, we shall prove that the weighted Hardy space {{\displaystyle H}}_{{{\displaystyle L}}_{\mathrm{1}},{{\displaystyle L}}_{\mathrm{2}},\omega }^{\mathrm{1}}({ℝ}^{{{\displaystyle n}}_{\mathrm{1}}}\times {ℝ}^{{{\displaystyle n}}_{\mathrm{2}}}) associated to operators L₁, L₂ on product domain, which is defined in terms of area function, has an atomic decomposition for some weight \omega.     

Measurement of the 20 and 90 keV resonances in the 18O(p,alpha)15N reaction via the Trojan horse method

The 18O(p,alpha)15N reaction is of primary importance in several astrophysical scenarios, including fluorine nucleosynthesis inside asymptotic giant branch stars as well as oxygen and nitrogen isotopic ratios in meteorite grains. Thus the indirect measurement of the low energy region of the 18O(p,alpha)15N reaction has been performed to reduce the nuclear uncertainty on theoretical predictions. In particular the strength of the 20 and 90 keV resonances has been deduced and the change in the reaction rate evaluated.     

Elaboration,Characterization and Thermal Decomposition Kinetics of New Nanoenergetic Composite Based on Hydrazine 3-Nitro-1,2,4-triazol-5-one and Nanostructured Cellulose Nitrate

This research aims to develop new high-energy dense ordinary- and nano-energetic composites based on hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) and nitrated cellulose and nanostructured nitrocellulose (NC and NMCC). The elaborated energetic formulations (HNTO/NC and HNTO/NMCC) were fully characterized in terms of their chemical compatibility, morphology, thermal stability, and energetic performance. The experimental findings implied that the designed HNTO/NC and HNTO/NMCC formulations have good compatibilities with attractive characteristics such as density greater than 1.780 g/cm³ and impact sensitivity around 6 J. Furthermore, theoretical performance calculations (EXPLO5 V6.04) displayed that the optimal composition of the as-prepared energetic composites yielded excellent specific impulses and detonation velocities, which increased from 205.7 s and 7908 m/s for HNTO/NC to 209.6 s and 8064 m/s for HNTO/NMCC. Moreover, deep insight on the multi-step kinetic behaviors of the as-prepared formulations was provided based on the measured DSC data combined with isoconversional kinetic methods. It is revealed that both energetic composites undergo three consecutive exothermic events with satisfactory activation energies in the range of 139–166 kJ/mol for HNTO/NC and 119–134 kJ/mol for HNTO/NMCC. Overall, this research displayed that the new developed nanoenergetic composite based on nitrated cellulose nanostructure could serve as a promising candidate for practical applications in solid rocket propellants and composite explosives.     

Experimental determination and prediction of (solid + liquid) phase equilibria for binary mixtures of aromatic and fatty acids methyl esters

Solid–liquid equilibria for binary mixtures of {methyl stearate (1) + biphenyl (2)}, {methyl stearate (1) + naphthalene (2)}, {methyl palmitate (1) + biphenyl (2)} and {methyl palmitate (1) + naphthalene (2)} were measured using differential scanning calorimeter. Simple eutectic behaviours for these systems were observed. The experimental results were correlated by means of the NRTL, Wilson, UNIQUAC and ideal models. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.5477 K (for UNIQUAC model) to 7.79 K; the deviations depend on the binary system studied and particular model used. The best solubility correlation was obtained with UNIQUAC model and this observation confirms previous results.