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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

CHARACTERIZATION OF INKJET PRINTED HIGH NITROGEN ENERGETIC MATERIALS AND BILAYER NANOTHERMITE

Adarsh Patra (6897383) 15 August 2019 (has links)
<p>This thesis presents work on two major areas of research. The first area of research involves the use of a dual-nozzle piezoelectric inkjet printing system to print bilayer aluminum bismuth (III) oxide nanothermite samples. The combinatorial printing method allows for separate fuel and oxidizer inks to be printed adjacent to each other at prescribed offset distances. The effect of the bilayer thickness on the burning rate of the samples is investigated using high-speed imaging. Analysis of the burning rate data revealed that there is no statistically significant relationship between these two parameters. This result was used to determine the dominant processes that control the propagation rate in nanothermite systems. It was concluded that convective processes dominate the burning rate rather than diffusive processes. The second area of research involved synthesizing inks suitable for inkjet printing using two promising high nitrogen energetic materials called BTATz and DAATO<sub>3.5</sub>. The performance of the developed inks was characterized using four experiments. The thermal stability and exothermic behavior of the inks were determined using DSC and TGA analysis. The results revealed that the inks are more thermally stable than the base materials. The inks were used to print lines that were subsequently used to determine burning rates. DAATO<sub>3.5</sub> samples were determined to have faster burning rates than BTATz. Closed pressure bomb experiments were conducted to determine the gas producing capability of the high nitrogen inks. BTATz samples showed better performance in terms of peak static pressures and pressurization rates. 3D printed microthrusters were developed to test the thrust performance of the inks. Peak thrust, total impulse, and specific impulse values are reported and were determined to be suitable for use with Class 1 micro-spacecraft. Finally, a microthruster array prototype was developed to demonstrate the capability to use additive manufacturing to create high packing density arrays.</p>
2

Termochemie polydusíkatých heterocyklických sloučenin / Thermochemistry of high nitrogen heterocyclic compounds

Bartošková, Monika January 2011 (has links)
The prediction of detonation properties of the new generation of high-nitrogen energetic materials (HNEM) is based on knowledge of their heats of formation, which are sum of values of particular nitrogen heterocyclic fragments. The diploma thesis describes theoretical calculations of heats of formation in gas phase ?f H°(298,g) for series of azines (number of N atoms 2-6) and azoles (number of N atoms 2-5) by means of quantum chemical methods. The semiempirical methods as PM3, DFT methods utilizing isodesmic approach and finally thermochemical G-recipes were used. All calculated values of heats of formation were scrutinized and for future application to HNEM materials the DFT B3LYP/cc-pVTZ method and thermochemical recipe T1 were recommended.
3

Termochemické vlastnosti vysokodusíkatých energetických materiálů / Thermochemical Properties of High Nitrogen Energetic Materials

Bartošková, Monika January 2015 (has links)
The main goal of the presented thesis is a theoretical study of heat of formation for high-nitrogen energetic materials. A modification of the classical approach to the isodesmic reactions is realized with the intent that molecules on both sides of the corresponding equation have not only the same number of atoms but also approximately the same size and skeletal similarity. This approach is designated as a method "Alternative Isodesmic Reaction (AIR method)". At its base, using the DFT B3LYP / cc-pVTZ and B3PW91 / cc-pVTZ, for the high nitrogen heterocycles, which are selected from the group of triazoles, triazines, tetrazines, the enthalpy of formation values the gaseous phase f H°(298,g), were obtained whose values are close to the published f H°(298,g). Their application in the calculation of the relevant characteristics of these heterocycles detonation gave real values.

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