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Nanoenergetic composites are nanostructured fuel and oxidizer mixtures that store a large amount of chemical energy and release it, typically in the form of heat, upon ignition. They are promising candidates for energy intensive applications such as propellants and pyrotechnics, due to their high energy density. The overall reaction kinetics of the heterogenous nanoenergetic system is controlled by mass transfer. The use of nanoparticles is to reduce diffusion length and thus increase energy release rate. The objective of the proposed research is to understand how intrinsic properties of fuel and oxidizer affect the reaction of nanoenergetic composites, and to develop novel, multifunctional nanoenergetic materials with tunable ignition threshold and energy release rate. Experiments were conducted utilizing primarily a time resolved Temperature-Jump time-of-flight mass spectrometer (T-Jump TOFMS) to analyze gas phase reaction intermediatespecies and products at a high heating rate (~105 K/s), along with a combustion cell for reactivity evaluation. New fuels including hydrogenated amorphous silicon, and oxidizers including oxygen deficient Co3O4-x and ferroelectric Bi2WO6 were investigated. The role of surface chemistry in the energetic characteristics of silicon nanoparticles was investigated, leading to the uncovering of a new reaction mechanism. Modulating the initiation temperature of aluminothermic reaction via defect engineered metal oxide was demonstrated. A study of piezoelectric oxidizers reveals the superior reactivity of a complex metal oxide. Moreover, tuning the energy release rate of I2O5 based biocidal nanoenergetic composites via a ternary system was studied. These results indicate that by modifying the chemistry or structure of fuels and oxidizers, the combustion characteristics of nanoenergetic composites can be tailored.

Energetic materials appear in a wide range of industrial and defense applications such as mining, construction, rocket propellant, design of munitions, etc. Understanding the physical and chemical processes that result in phenomena leading to initiation is critical for the safe development, usage, transport, and storage of high-performance energetics. A long held belief is that shock energy induces initiation of an energetic material through an energy up-pumping mechanism involving phonon scattering through doorway modes. In Chapters 4 and 6, a 3-phonon theoretical analysis of vibrational energy up-pumping in RDX is presented that considers possible doorway pathways through which energy transfer occurs. The vibrational energy transfer is modeled via 3-phonon scattering processes based on Fermi’s Golden Rule. Our results indicate that the low frequency vibrational modes (below ~100 cm-1) scatter less than 0.5% of the vibrational energy directly to the critical high frequency intramolecular vibrations. In contrast, the mid-frequency modes between 457 and 462 cm-1 and between 831 and 1331 cm-1 are the most critical for vibrational heating of the critical intramolecular vibrations such as N-N stretching. In Chapters 3 and 5, we examine the nature of thermal transport and how bond strain and rotation carry heat in RDX. To draw the distinction between propagating and diffusive carriers of heat, we compare the thermal conductivity estimates from three microscale models: Phonon Gas Model, Cahill-Watson-Pohl formula, and Allen-Feldman harmonic theory. We observed that due to a strong crystal anharmonicity, diffusive carriers contribute to over 95% of the thermal conductivity in RDX. These results indicate that van der Waals bonded organic crystalline solids conduct heat in a manner more akin to amorphous materials than simple atomic crystals. In Chapter 7, we perform a numerical experiment to investigate the effects of stimulating different IR active vibrational modes on cha

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch), This work is part of the interlaboratory collaboration to study the stability of organic solar cells containing PCDTBT polymer as a donor material. The varieties of the OPV devices with different device architectures, electrode materials, encapsulation, and device dimensions were prepared by seven research laboratories. Sets of identical devices were aged according to four different protocols: shelf lifetime, laboratory weathering under simulated illumination at ambient temperature, laboratory weathering under simulated illumination, and elevated temperature (65°C) and daylight outdoor weathering under sunlight. The results generated in this study allow us to outline several general conclusions related to PCDTBT-based bulk heterojunction (BHJ) solar cells. The results herein reported can be considered as practical guidance for the realization of stabilization approaches in BHJ solar cells containing PCDTBT.

The atmospheric pressure plasma sources with a coaxial geometry were used for generation of the radio frequency, microwave and pulsed dc plasmas inside water and aqueous solutions. Pulsed dc plasma generated in ethanol-water mixtures leads to production of the hydrogen-rich synthesis gas with hydrogen content up to 65 % The effect of various plasma generation regimes on the performance of plasma, on the hydrogen production efficiency and on the hydrogen-rich synthesis gas production was examined. A role of the composition of the ethanol-water mixture was investigated.

This work is part of the interlaboratory collaboration to study the stability of organic solar cells containing PCDTBT polymer as a donor material. The varieties of the OPV devices with different device architectures, electrode materials, encapsulation, and device dimensions were prepared by seven research laboratories. Sets of identical devices were aged according to four different protocols: shelf lifetime, laboratory weathering under simulated illumination at ambient temperature, laboratory weathering under simulated illumination, and elevated temperature (65 °C) and daylight outdoor weathering under sunlight. The results generated in this study allow us to outline several general conclusions related to PCDTBT-based bulk heterojunction (BHJ) solar cells. The results herein reported can be considered as practical guidance for the realization of stabilization approaches in BHJ solar cells containing PCDTBT.

The study of the thesis is about the energetic material that are used in semiconductor industries. A process model is developed to simulate the processes that results in some run-away exothermic reactions involving reactive deposited materials in the downstream of typical deposition reactors used in semiconductor manufacturing, such as chemical vapor deposition(CVD) and atomic level deposition(ALD). The potential sources of energetic material have been pointed out in the study. This model takes into account various transport and reactions involved in the process and reveals the details of the mechanism that trigger these uncontrolled energetic reactions and the potential damaging effects due to formation of hotspots. Using the developed model, a parameter study is conducted to see the effect of various parameters on this process. In particular, the concentration of reactants, the accumulation due to competition between the deposition and reaction, the gas flow rate and the properties of reactants and reactions play the key role in the trigger mechanism as well as the location and time of hot spot formation. Based on the results, a number of techniques are suggested to minimize and mitigate the occurrence of these energetic events.

This thesis represents a brief overview of author´s research work done in the characterization of explosives, their detonation properties and effects they impose on the surroundings. This includes development of methods and instrumentation as well as their application in particular cases of individual explosives and explosive composition. The topics studied cover determination of detonation velocity with optical methods, determination of detonation pressure by shock or particle velocity measurements, studies of the ability of explosives to accelerate inert materials, characterization of material under explosive or shock loading and the issues of blast wave generation in air by detonating explosive., Tato habilitační práce prezentuje stručný přehled autorovy vědecko-výzkumné činnosti v oblasti charakterizace výbušnin, jejich vlastností a působení na okolí. Práce zahrnuje nejen vývoj vhodných metod a instrumentální techniky nezbytných pro tuto charakterizaci, ale i jejich aplikaci na konkrétní výbušniny. Zkoumaná témata zahrnují měření detonační rychlosti optickými metodami, stanovení detonačního tlaku z měření rychlosti rázových vln nebo rychlosti částic, studie schopnosti výbušnin urychlovat inertní materiály, charakterizaci inertních materiálů při výbušném nebo nárazovém zatížení a problémy spojené se vznikem vzdušných rázových vln vlivem detonace trhaviny., Faculty of Chemical Technology. Institute of Energetic Materials., Dokončená práce s úspěšnou obhajobou

The tetrahydrate of the tetrapotassium salt of octahydroimidazo-[4,5-d]imidazol-1,3,4,6-tetrasulfonic acid (TACOS-K), an new energetic material, was investigated in terms of its crystal structure, heat of combustion, thermal stability and decomposition kinetics. Its heat of combustion is -5487±96 J.g-1 from which a heat of formation of -3150 kJ.mol-1 was estimated. It has been found that this compound has a hexagonal crystal space group with a density of 2.026 g.mol-1/150 K. The organic anionic skeleton of the TACOS-K molecule is distinctly deformed. Six tetraanions interconnected by a coordination to the potassium cations and hydrogen bridges to water molecules form hydrophilic as well as hydrophobic cavities. As an intermediate to synthesize cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (BCHMX), it decomposes at around 31°C with a first peak temperature range of 46.6-94.3 °C due to loss of water, depending on the heating rates. Hydrolysis of the N-S bonds might play an important role here. Crystalline water evaporation competes with this hydrolysis. TACOS-K has a residual mass of about 46% at 2°C.min-1, which increases with the heating rate. Peak of the exothermic process occurs at 235.6 °C at the same heating rate with an enthalpy change of 164 J.g-1. Dehydration occurs with an energy barrier of 36.7 kJ mol-1 followed by a shoulder mass loss process with a much higher activation energy 110.6 kJ mol-1, while the activation energy for the main exothermic reaction is about 136.2 kJ mol-1., Tetrahydrát na tetradraselné soli oktahydroimidazo- [4,5-d] imidazol-1,3,4,6-tetrasulfonové kyseliny (TACOS-K) je nový energetický materiál, zkoumaný z hlediska své krystalické struktury, spalného tepla, tepelné stability a rozkladné kinetiky. Jeho spalné teplo je -5487 ± 96 J.g-1, ze kterého bylo odhadnuté slučovací teplo -3150 kJ.mol-1. Bylo zjištěno, že tato sloučenina má hexagonální krystalovou strukturu s hustotou 2.026 g.mol-1 při 150 K. Skelet organického aniontu molekuly TACOS-K je výrazně deformovaný. Šest tetraanionů je koordinačně propojeno s kationtů draslíku a vodíkovými můstky s molekulmi vody tvoří hydrofilní i hydrofobní dutiny. Tento meziprodukt pro syntézu cis-1,3,4,6-tetranitro-oktahydroimidazo- [4,5-d] imidazolu (BCHMX) se rozkládá při teplotě okolo 31 ° C, s prvním vrcholem v rozmezí teplot 46.6-94.3 ° C v důsledku ztráty vody a v závislosti na rychlosti ohřevu. Hydrolýza vazeb N-S zde může hrát důležitou roli. Odpařování krystalické vody soutěží s touto hydrolýzou. V TGA má TACOS-K zbytkovou hmotu 46% při vzestupu teploty 2 ° C.min-1, což se zvyšuje s rychlostí ohřevu. Vrchol exotermického procesu se vyskytuje při 235,6 ° C a při stejné rychlosti ohřevu s entalpickou změnou 164 J.g-1. Dehydratace nastává s energetickou bariéru 36,7 kJ mol-1 s následným hromadným procesem ztráty hmotnosti s mnohem vyšší aktivační energie 110,6 kJ mol-1, zatímco aktivační energie pro hlavní exotermní reakci je asi 136,2 kJ mol-1.

Energetic materials are materials which can release large amounts of energy in a short time interval. When the size of energetic materials is reduced from micro into nanoscale, the reactivity of energetic materials increases dramatically due to increase in intimate contact and faster mass and heat transfer. Finding an efficient way to synthesize energetic nanocomposites has become an import research topic. Here I demonstrate the use of electrospray methods to generate mesostructured microparticles containing nanomaterials and a gas generator. The system was designed for characterization of the size distribution as well as combustion properties. In this thesis, size distribution of the Al/NC mesoparticles is tuned from 0.7-2.0 µm, and the ignition delay is shown significantly decrease (15 ms to 3 ms) compared to nano-size Al. The burn time is also decreased significantly (4036 µs to 366 µs) by using electrospray assembly. This demonstrated that assembly of nanocomponents can significantly impact combustion performance.

The decomposition pathways of ionized ammonium dinitramide (ADN) have been analyzed using the B3LYP and the M06-2X density functional theory methods, coupled cluster theory and the composite CBS-QB3 method. Ionization and subsequent decomposition of the major decomposition products have also been studied. The ADN(+) ion dissociates into the stable DN radical and NH4+ with a dissociation enthalpy of 50 kJ/mol. The subsequently formed DN+ ion has an activation enthalpy of 102 kJ/mol for decomposition into N2O, O-2 and NO+. A competing pathway for ionization and decomposition of ADN involves the HDN+ ion, which dissociates into NO2+ and HNNO2 with a barrier of only 17 kJ/mol. The ionization product HNNO2+ is stable toward further decomposition, and the barrier for isomerization to HONNO+ is 167 kJ/mol. The computed adibatic ionization potentials of ADN, HDN, DN and HNNO2 are 9.4, 11.5, 10.2 and 10.9 eV, respectively. The results of the study have implications for the future use of ADN in propellants for electromagnetic space propulsion., QC 20131127

Catastrophic initiation of an energetic material consists of a complex, interactive, sequential train of mechanistic mechanical, physical, and chemical processes which occur over a finite time period and proceed from macroscopic into sub-microscopic composition levels (bulk > crystalline > molecular > atomic). Initiation results when these processes proceed at a rate which generates sufficient energy (heat) to reach a threshold stage within this finite time period. Thus, the rate at which these mechanistic processes occur defines initiation sensitivity and affects performance. Thermochemical decomposition processes regulate the rate at which heat energy is released at the molecular level, and therefore to some extent, control energetic material initiation sensitivity and performance characteristics. Kinetic deuterium isotope effect (KDIE) data, obtained during ambient pressure thermochemical decomposition process, identifies the mechanistic rate-controlling bond rupture which ultimately regulates the energy release rate of a given energetic material. This same rate-controlling bond rupture also appears as a significant rate-limiting feature in higher order deflagration, combustion, and explosion phenomena. The effect the KDIE-determined rate-controlling bond rupture exerts on initiation sensitivity, and its potential influence in combustion and explosion performance is delineated., Submitted for presentation at the International Seminar on New Trends in Research of Energetic Materials (10th), held in Pardubice, Czech Republic, on 25-27 Apr 2007.

V textu diplomové práce je nejprve stručně pojednáno o problematice měření parametrů energetických materiálů v obecné rovině. Důraz je kladen především na popis detonační rychlosti a stručný rozbor nejčastěji používaných metod. Převážná část textu je věnována návrhu a popisu systému, jenž byl vytvořen v prostředí ISE Design Suite s využitím jazyka VHDL. Vývoj byl prováděn s ohledem na pozdější integraci do desky s FPGA a A/D převodníky. Funkčnost algoritmu detekce, implementovaného na základě modelu, byla ověřena v závěrečné části práce simulací zpracování reálných signálů optických sond., In the text of the master´s thesis, it is at first briefly referred about Energetic Material Measurement topic in general. Emphasis is placed especially at the description of the Velocity of Detonation and short analysis of selected measurement method. The most significant part of the paper is dedicated to the design and description of the system that was created in ISE Design Suite environment using VHDL language. The development was performed with respect to oncoming integration into the board with FPGA and A/D converters. The operation of detection algorithm which was created based on the MATLAB model was verified in the final part of the thesis by simulation of processing of real optical probe signals.

V textu diplomové práce je nejprve stručně pojednáno o problematice měření parametrů energetických materiálů v obecné rovině. Důraz je kladen především na popis detonační rychlosti a stručný rozbor nejčastěji používaných metod. Převážná část textu je věnována návrhu a popisu systému, jenž byl vytvořen v prostředí ISE Design Suite s využitím jazyka VHDL. Vývoj byl prováděn s ohledem na pozdější integraci do desky s FPGA a A/D převodníky. Funkčnost algoritmu detekce, implementovaného na základě modelu, byla ověřena v závěrečné části práce simulací zpracování reálných signálů optických sond., In the text of the master´s thesis, it is at first briefly referred about Energetic Material Measurement topic in general. Emphasis is placed especially at the description of the Velocity of Detonation and short analysis of selected measurement method. The most significant part of the paper is dedicated to the design and description of the system that was created in ISE Design Suite environment using VHDL language. The development was performed with respect to oncoming integration into the board with FPGA and A/D converters. The operation of detection algorithm which was created based on the MATLAB model was verified in the final part of the thesis by simulation of processing of real optical probe signals.

V textu diplomové práce je nejprve stručně pojednáno o problematice měření parametrů energetických materiálů v obecné rovině. Důraz je kladen především na popis detonační rychlosti a stručný rozbor nejčastěji používaných metod. Převážná část textu je věnována návrhu a popisu systému, jenž byl vytvořen v prostředí ISE Design Suite s využitím jazyka VHDL. Vývoj byl prováděn s ohledem na pozdější integraci do desky s FPGA a A/D převodníky. Funkčnost algoritmu detekce, implementovaného na základě modelu, byla ověřena v závěrečné části práce simulací zpracování reálných signálů optických sond., In the text of the master´s thesis, it is at first briefly referred about Energetic Material Measurement topic in general. Emphasis is placed especially at the description of the Velocity of Detonation and short analysis of selected measurement method. The most significant part of the paper is dedicated to the design and description of the system that was created in ISE Design Suite environment using VHDL language. The development was performed with respect to oncoming integration into the board with FPGA and A/D converters. The operation of detection algorithm which was created based on the MATLAB model was verified in the final part of the thesis by simulation of processing of real optical probe signals.

This dissertation examines the electronic structure and thermochemistry of low-valent aluminum clusters that may serve as precursors for new energetic materials. Clusters such as Al₅ₒ0Cp* ₁₂ (Cp*=C₅Me₅) have theoretical heats of combustion more than twice that of common high explosives and potentially faster combustion kinetics than bulk metals. The tetrameric aluminum cluster Al₄Cp* ₄ is a prototypical monovalent aluminum compound, and a potential precursor for these larger metalloid clusters. The synthesis of Al₄R₄ (R=C ₅Me₄Pr, C ₅Me₄iPr), two clusters similar to Al₄Cp*₄, was recently reported and the effect of their increased steric bulk is discussed here. Experimental results and density functional theory (DFT) analysis show that these clusters are enthalpically more stable than the Cp* variant, due primarily to non-covalent interactions (NCIs) across ligand groups. These NCIs show how ligand steric bulk can add stability to tetrameric clusters in addition to low-valent metal bonding. Similar calculations are performed on seven other homoleptic Cp-related clusters with varying levels of steric bulk. DFT results are used to predict monomer/tetramer equilibrium for all clusters and show trends counter to expectations regarding the role of ligand bulk. This equilibrium could be an important component in determining the viability of a cluster as a precursor for larger clusters., http://archive.org/details/ligandeffectsinl1094556186, Commander, United States Navy, Approved for public release; distribution is unlimited.

V textu diplomové práce je nejprve stručně pojednáno o problematice měření parametrů energetických materiálů v obecné rovině. Důraz je kladen především na popis detonační rychlosti a stručný rozbor nejčastěji používaných metod. Převážná část textu je věnována návrhu a popisu systému, jenž byl vytvořen v prostředí ISE Design Suite s využitím jazyka VHDL. Vývoj byl prováděn s ohledem na pozdější integraci do desky s FPGA a A/D převodníky. Funkčnost algoritmu detekce, implementovaného na základě modelu, byla ověřena v závěrečné části práce simulací zpracování reálných signálů optických sond., In the text of the master´s thesis, it is at first briefly referred about Energetic Material Measurement topic in general. Emphasis is placed especially at the description of the Velocity of Detonation and short analysis of selected measurement method. The most significant part of the paper is dedicated to the design and description of the system that was created in ISE Design Suite environment using VHDL language. The development was performed with respect to oncoming integration into the board with FPGA and A/D converters. The operation of detection algorithm which was created based on the MATLAB model was verified in the final part of the thesis by simulation of processing of real optical probe signals.

V textu diplomové práce je nejprve stručně pojednáno o problematice měření parametrů energetických materiálů v obecné rovině. Důraz je kladen především na popis detonační rychlosti a stručný rozbor nejčastěji používaných metod. Převážná část textu je věnována návrhu a popisu systému, jenž byl vytvořen v prostředí ISE Design Suite s využitím jazyka VHDL. Vývoj byl prováděn s ohledem na pozdější integraci do desky s FPGA a A/D převodníky. Funkčnost algoritmu detekce, implementovaného na základě modelu, byla ověřena v závěrečné části práce simulací zpracování reálných signálů optických sond., In the text of the master´s thesis, it is at first briefly referred about Energetic Material Measurement topic in general. Emphasis is placed especially at the description of the Velocity of Detonation and short analysis of selected measurement method. The most significant part of the paper is dedicated to the design and description of the system that was created in ISE Design Suite environment using VHDL language. The development was performed with respect to oncoming integration into the board with FPGA and A/D converters. The operation of detection algorithm which was created based on the MATLAB model was verified in the final part of the thesis by simulation of processing of real optical probe signals.

V textu diplomové práce je nejprve stručně pojednáno o problematice měření parametrů energetických materiálů v obecné rovině. Důraz je kladen především na popis detonační rychlosti a stručný rozbor nejčastěji používaných metod. Převážná část textu je věnována návrhu a popisu systému, jenž byl vytvořen v prostředí ISE Design Suite s využitím jazyka VHDL. Vývoj byl prováděn s ohledem na pozdější integraci do desky s FPGA a A/D převodníky. Funkčnost algoritmu detekce, implementovaného na základě modelu, byla ověřena v závěrečné části práce simulací zpracování reálných signálů optických sond., In the text of the master´s thesis, it is at first briefly referred about Energetic Material Measurement topic in general. Emphasis is placed especially at the description of the Velocity of Detonation and short analysis of selected measurement method. The most significant part of the paper is dedicated to the design and description of the system that was created in ISE Design Suite environment using VHDL language. The development was performed with respect to oncoming integration into the board with FPGA and A/D converters. The operation of detection algorithm which was created based on the MATLAB model was verified in the final part of the thesis by simulation of processing of real optical probe signals.