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Derivative-free methods for nonlinear programming with general lower-level cons...
Diniz-Ehrhardt,M. A.; Martínez,J. M.; Pedroso,L. G.Augmented Lagrangian methods for derivative-free continuous optimization with constraints are introduced in this paper. The algorithms inherit the convergence results obtained by Andreani, Birgin, Martínez and Schuverdt for the case in which analytic derivatives exist and are available. In particular, feasible limit points satisfy KKT conditions under the Constant Positive Linear Dependence (CPLD) constraint qu...
Low-Temperature FTIR Spectroscopic and Theoretical Study on an Energetic Nitroi...
Simões, P. N.; Reva, I.; Pedroso, L. M.; Fausto, R.; Portugal, A. A.This paper presents an overview of recent progress in spectroscopic studies of the energetic nitroimine 4,6-bis(nitroimino)-1,3,5-triazinan-2-one (DNAM), based on experimental and theoretical data. The following topics are considered: variable temperature FTIR spectroscopy (4000−400 cm-1) applied to the study of natural and isotopically substituted (deuterated) samples aiming to obtain a successful vibrational...
Crystal and Molecular Structure of 4,6-Bis(nitroimino)-1,3,5-triazinan-2-one: ...
Simões, P. N.; Pedroso, L. M.; Beja, A. M. Matos; Silva, M. Ramos; MacLean, Elizabeth; Portugal, A. A.This paper provides an overview of recent progress on structural data on the title compound. Theoretical work based on quantum mechanical calculations was performed to gain some understanding on the heterocyclic tautomerism potentially exhibited by the compound. The computational studies encompassed a wide range of tautomers/conformers, allowing the determination of the most probable molecular structure. In the...
Cyanuric acid-epichlorohydrin prepolymers
Pedroso, L. M.; Simões, P.; Portugal, A.In this study, we investigated the reaction of cyanuric acid and epichlorohydrin (ECH). SnCl4 was used as a catalyst. Several reaction conditions were tested, and the products were analyzed by means of Fourier transform infrared and 1H-NMR spectroscopy, hydroxyl group content, molar mass, elemental and thermal analysis, viscosity, and density. ECH reacted with the amine groups of the cyanuric acid ring to form ...
New Propellant Component, Part II. Study of a PSAN/DNAM/HTPB Based Formulation
Simões, P.; Pedroso, L.; Portugal, A.; Plaksin, I.; Campos, J.A study of DNAM as a candidate ingredient for propellant formulations is reported. A formulation including DNAM and based on Phase Stabilized Ammonium Nitrate (PSAN) and Hydroxy-Terminated-Poly Butadiene (HTPB) was selected for the study. This includes thermoanalytical measurements on the mixtures of solid components and propellant samples. Performance is assessed by burning rate measurements. A new small-scale...
New Propellant Component, Part I. Study of 4,6-Dinitroamino-1,3,5-Triazine-2(1 ...
Simões, P.; Pedroso, L.; Portugal, A.; Carvalheira, P.; Campos, J.This paper reports a study of the synthesis and characterization of 4,6-dinitroamino-1,3,5-triazine-2(1 H)-one (DNAM) carried out under the perspective of looking for new ingredients in propellant formulations. Emphasis is given to the characterization of DNAM. The following attributes were identified: low sensitivity to impact and friction, thermal stability over a wide temperature range, energetic nature, hig...
Thermal decomposition of solid mixtures of 2-oxy-4,6-dinitramine-s-triazine (DN...
Simões, P. N.; Pedroso, L. M.; Portugal, A. A.; Campos, J. L.The thermal decomposition of solid mixtures of 2-oxy-4,6-dinitramine-s-triazine (DNAM) and phase stabilized ammonium nitrate (PSAN) at different mass ratios has been studied. Simultaneous thermal analysis (DSC/TG) and thermomicroscopy have been used. It was found that PSAN promotes the lowering of the decomposition temperature of DNAM. The beginning of this process occurs when both components are in the solid s...
Study of the decomposition of phase stabilized ammonium nitrate (PSAN) by simul...
Simões, P. N.; Pedroso, L. M.; Portugal, A. A.; Campos, J. L.Ammonium nitrate (AN) has been extensively used both in explosive and propellant formulations. Unlike AN, there is a lack of information about the thermal decomposition and related kinetic analysis of phase stabilized ammonium nitrate (PSAN). Simultaneous thermal analysis (DSC-TG) has been used in the thermal characterisation of a specific type of PSAN containing 1.0% of NiO (stabilizing agent) and 0.5% of Petr...
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