scholarly journals Experimental and Theoretical Study on Three Combustion Models for the Determination of the Performance Parameters of Nitrocellulose - Based Propellants

2020 ◽  
Vol 71 (9) ◽  
pp. 87-97
Author(s):  
Titi Paraschiv ◽  
Tudor Viorel Tiganescu ◽  
George Ovidiu Iorga ◽  
Raluca Elena Ginghina ◽  
Octavian Constantin Grigoroiu
Keyword(s):  
Chemical Composition ◽  
Energetic Materials ◽  
Specific Volume ◽  
Flame Temperature ◽  
Performance Parameters ◽  
Heat Of Explosion ◽  
Combustion Gases ◽  
Combustion Models ◽  
Double Base

Nitrocellulose based propellants are the main materials used for ballistic and rocket applications. The chemical composition of the propellants, the loading density and propellant grain geometry are the decisive parameters that influence the performance parameters in ballistic application. In this paper the authors evaluate three models of combustion for energetic materials for the determination of heat of explosion and specific volume together with the adiabatic flame temperature. The authors select six types of propellant (two simple base propellants, two double base propellants based on nitroglycerine and two triple base propellants based on nitroguanidine) and the authors determined the heat of explosion and specific volume using a bomb calorimeter and a Julius-Peters device. The results obtained from the combustion models were compared to the experimental results and assumptions were done on the influence of pressure and temperature on the chemical composition of combustion gases produced by the confined deflagration of nitrocellulose-based propellants.

Preparation of graft copolymers by the reaction of polymeric acyl chlorides with monohydroxy-terminated polymers: An introductory study

1988 ◽  
Vol 53 (8) ◽  
pp. 1735-1744 ◽  
Author(s):  
Jitka Horská ◽  
Jaroslav Stejskal ◽  
Pavel Kratochvíl ◽  
Aubrey D. Jenkins ◽  
Eugenia Tsartolia ◽  
...  
Keyword(s):  
Light Scattering ◽  
Chemical Composition ◽  
Statistical Model ◽  
Graft Copolymers ◽  
Coupling Reaction ◽  
Molecular Characteristics ◽  
Gel Formation ◽  
Acyl Chlorides ◽  
Molecular Weights

An attempt was made to prepare well-defined graft copolymers by the coupling reaction between acyl chloride groups located along the backbone chain and monohydroxy-terminated grafts prepared separately. The molecular weights and the parameters of heterogeneity in chemical composition of the products were determined by light scattering and osmometry. The determination of molecular characteristics revealed that the degree of grafting was low. The results therefore could not be confronted with a statistical model at this stage. The problems encountered in the synthesis, e.g., gel formation, and the data relating to the soluble products are discussed.

Mechanical Behaviour of CoCrMo Alloy with Si Content

2015 ◽  
Vol 754-755 ◽  
pp. 1017-1022 ◽  
Author(s):  
Petrică Vizureanu ◽  
Mirabela Georgiana Minciună ◽  
Dragoş Cristian Achiţei ◽  
Andrei Victor Sandu ◽  
Kamarudin Hussin
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Testing Machine ◽  
Base Material ◽  
Optical Emission ◽  
Experimental Tests ◽  
Optical Emission Spectrometry ◽  
Emission Spectrometry ◽  
Standard Samples

.The paper present aspects about the obtaining of non-precious dental alloys (type CoCrMo and CoCrMoSi7), the determination of chemical composition by optical emission spectrometry and the experimental tests for determining the tensile strength, made on standard plate samples. The base material used in experiments was a commercial alloy, from CoCrMo system, which belongs to the class of dental non-precious alloys, intended to medical applications. The obtaining of studied alloy was made on arc re-melting installation, under vacuum, type MRF ABJ 900. The process followed to realize a rapid melting, with a maximum admissible current intensity. The samples for tests were obtained by casting in an electric arc furnace, under vacuum, in optimal conditions for melting and solidification and processing by electro-erosion, to eliminate all the disturbing factors which come by processing conditions for the samples. The determination of chemical composition for cobalt based alloys, by optical emission spectrometry, was made on SpectromaxX equipment with spark. The electrical discharge is made with the elimination of an energy quantity, fact which determine plasma forming and light issue. Tensile tests for standard samples, made from cobalt based alloy, was made on Instron 3382 testing machine, and assisted by computer. The obtained results are: elongation, elasticity modulus, tensile strength and offer complete information about the analyzed mechanical properties. For the certitude of obtained experimental results, the tests were made on samples with specific dimensions according ISO 6892-1:2009(E) standard, both for the tensile strength, and also machine operation.

Determination of Relationship between Chemical Composition of Electrolyte and Surface Sample Quality

2015 ◽  
Vol 669 ◽  
pp. 150-157
Author(s):  
Peter Michal ◽  
Alena Vagaská ◽  
Miroslav Gombár
Keyword(s):  
Sodium Chloride ◽  
Chemical Composition ◽  
Oxalic Acid ◽  
Boric Acid ◽  
Oxide Layer ◽  
Surface Finish ◽  
Chemical Factors ◽  
Substrate Sample

Paper tracks experimentally confirmed relationship between chemical composition of electrolyte and resulting surface finish quality of created oxide layer during the process of anodic oxidation of aluminium. Examined chemical factors were: concentrations of sulphuric acid, oxalic acid, boric acid and sodium chloride. Aggressive effects of electrolyte were chosen as indicator of resulting layer quality – presence and extent of etching of used substrate sample.

Laser-induced breakdown spectroscopy (LIBS) technique for the determination of the chemical composition of complex inorganic materials

2014 ◽  
Author(s):  
Łukasz Łazarek ◽  
Arkadiusz J. Antończak ◽  
Michał R. Wójcik ◽  
Paweł E. Kozioł ◽  
Bogusz Stępak ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Inorganic Materials ◽  
Laser Induced Breakdown Spectroscopy ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown
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