High energy density materials based on fluorinated bridged trinitromethyl azo triazole derivatives: a quantum chemical study of thermodynamic and energetic properties

This research article published by Springer Nature Switzerland AG., 2020High energy density materials (HEDM) have gained extensive attention due to their energetic properties and safety issues. Nitro and fluoro groups, among others, have become viable substituents on the triazole framework because of their particular contribution to detonation properties and moderate sensitivity. In this study, Density Function Theory (DFT) approach was employed to design fluorinated bis(trinitromethyl) azo triazoles. The molecular structures, thermodynamic properties of gaseous species (e.g., enthalpies of detonation and enthalpies of formation) and energetic properties of solid materials (detonation heat Q, pressure PD and velocity VD) have been investigated. The best characteristics attained for the designed azo fluorinated solid compounds are as follows: Q 1650–1690 cal g−1, PD 44–46 GPa and VD 9.8 km s−1. These characteristics are superior to those of conventional explosives, indicating that fluorinated bis(trinitromethyl) azo triazoles are promising HEDM

Historia de expeditione Friderici Imperatoris

monografi

High energy density materials based on fluorinated bridged trinitromethyl azo triazole derivatives: a quantum chemical study of thermodynamic and energetic properties

A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Master’s in Materials Science and Engineering of the Nelson Mandela African Institution of Science and TechnologyHigh energy density materials (HEDM) have gained extensive attention due to their energetic properties and safety issues. Nitro and fluoro groups, among others, have become viable substituents in the HEDM triazole framework because of their particular contribution to detonation properties and moderate sensitivity. In this study, fluorinated bis(trinitromethyl) azo triazoles were designed theoretically using the Density Function Theory (DFT) approach with hybrid functional B3LYP. The molecular structures, thermodynamic properties of gaseous species (e.g., enthalpies of detonation and enthalpies of formation) and energetic properties of solid materials (detonation heat Q, pressure PD and velocity VD) have been investigated. The best characteristics attained for the designed azo fluorinated solid compounds are as follows: Q 1650 – 1690 cal g –1 , PD 44 – 46 GPa and VD 9.8 km s –1 . These characteristics are superior to those of conventional explosives, indicating that fluorinated bis(trinitromethyl) azo triazoles are promising HEDM

Potenziale und Kosten für biogene Treibstoffe der 1. Generation

Diese Diplomarbeit wurde von Ao.Univ.Prof.Dr.techn. Reinhard HAAS am Institut für Elektrische Anlagen und Energiewirtschaft der TU-Wien betreut. Um die Abhängigkeit von fossilen Energieträgern zu verringern und die Emission von Treibhausgasen zu reduzieren, verabschiedete die EU die Biokraftstoffrichtlinie, in der Beimischungsziele für Biokraftstoffe festgelegt werden. Damit gewinnt die Produktion von Biokraftstoffen an Bedeutung und wird von der EU gefördert. Die Potenziale für Biokraftstoffe der 1. Generation, insbesondere Biodiesel und Bioethanol, stellen den zentralen Teil der vorliegenden Arbeit dar. Dazu wurden fünf ausgewählte Studien über Flächen und Produktionspotenziale untersucht, wobei besonderes Augenmerk auf deren Grundannahmen, Arbeitsweisen und Ergebnissen gelegt wurde. Um die Studien systematisch miteinander vergleichen zu können, wird zuerst ein Raster entwickelt, um Gemeinsamkeiten und Berührungspunkte herauszufiltern, und diese dann tabellarisch darzustellen. Energiepflanzen, die für Biokraftstoffproduktion in der EU geeignet sind, werden vorgestellt und hinsichtlich ihrer Ansprüche an Boden und Klima, Kulturdaten und Nährstoffversorgung untersucht. Darüber hinaus geht die Arbeit auf die Fruchtfolgenthematik und die möglichen Auswirkungen auf die Erträge der Energiepflanzen ein. Diese Arbeit fokusiert auf den landwirtschaftlichen Bereich der Thematik, es wurden die Rohstoffkosten unter dem Aspekt der Deckungsbeitragsberechnung untersucht. Diese Arbeit zeigt, dass durchaus Flächenpotenziale bestehen, die Erträge aber stark standortabhängig sind und durch angepasste Fruchtfolgen gesteigert werden können.Weiters werden durch die Flächenfreisetzung aus den Überschüssen oft nicht die ertragstärksten Flächen zur Bioenergieproduktion verwendet.In order to reduce dependency on fossil fuel energy sources, and to reduce emissions of greenhouse gases, the EU passed directives for biofuels in which aims of blend were established. Because of this, the production of biofuels is relevant and is promoted by the EU. The potential of the first generation of biofuels, in particular biodiesel and bioethanol, constitute the main topic of this paper. Five selected studies on areas and energy potentials were analyzed, with special attention given to their basic assumptions, methods of operations and results. To systematically compare the studies a chart was developed in order to filter similarities and relationships. Plants which are eligible for the production of biofuel in the EU are introduced and analyzed according to their soil and climate requirements, cultivation data and their nutrient supply. In addition this paper also discusses crop rotation and its possible ramification on the energy yield of plants. As this paper focuses on the agricultural aspect of the topic, the costs of resources with regard to the contribution margin were analyzed. This paper shows that potentials of area do exist. The yield depends on the location, and it can be increased by appropriate crop rotation. Due to the assignment of released areas off the surplus, very often it is not the most productive areas that are utilized for the production of biofuels.Ansbert SturmZsfassung in engl. SpracheWien, Univ. für Bodenkultur, Dipl.-Arb., 2008(VLID)112748

František Steiner, Fußball unterm gelben Stern. Die Liga im Ghetto Theresienstadt 1943–44

   &nbsp

Is the Sprawling Urban Form Sustainable? : An Investigation of the Ecological Impacts of Low-density Fringe Development

The traditional postwar city has been characterized by extensive low-density residential growth coupled with an over-reliance on the private automobile for mobility in the city. As human activities seem to be the defining determinants of the unsustainable urban fabric, it is essential to understand the long-term impacts of the contemporary urban lifestyle and how it detrimentally relates to the planet. In this research, two urban development concepts were investigated to determine the type of urban form suitable for structuring a more sustainable city. By comparing low-density suburban communities to core area communities using an environmental impact assessment tool supported with empirical observations and theory, the differences between these two urban concepts were obtained. Using the ecological footprint methodology, footprint estimations were done for suburban communities (N = 8) and core area communities (N = 4) in Calgary to find out their disparities. The research used neighborhood household income/consumption as a proxy for estimating the ecological footprint values and footprints obtained ranged between 11.35 Gha/cap and 6.77 Gha/cap. All the data used in this research are secondary data obtained from Statistics Canada, The City of Calgary, and a Canadian national footprint study by Mackenzie et al (2008). The research suggests that drawing growth to core areas is a salient part of reducing ecological footprint but it needs to be complemented with novel ways of urban fringe development to maximize the outcomes of ecological footprint interventions. Since the highest ecological footprint values were found in high-income suburban neighborhoods, it is relevant to approach the problem by utilizing income as an integrator in making the urban form less suburban and also changing the structure of the few indispensable suburban communities