Download or read book Synthesis and Optical Ignition of Aluminum and Silicon based Energetic Materials written by Yuma Ohkura and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Energetic materials, aluminum (Al) and silicon (Si), due to their large volumetric energy densities, earth abundance, and low cost, have broad applications in propulsion, thermal batteries, waste disposal and power generation for microsystems. The energetic materials are commonly prepared by mixing fuel and oxidizer powders, however, the energy release rates are slow and difficult to ignite. Furthermore, the large portion of the reactants remains unburned due to the formation of the oxide layer during the reaction. Optimized energetic materials would have the reactive components mixed on a scale as fine as possible to reduce the mass transport distance and facilitate the ignition. This leads to the idea of reducing the sizes of energetic materials down to nanoscale to increase the surface area and contact area between the fuel and oxidizer. In this study, we investigated two new areas: 1) the effects of the nanostructured morphology on the exothermic reaction of Al and CuO, 2) demonstrate and understand the flash ignition of Al nanoparticles (NPs), and extending the flash ignition to Al microparticles (MPs) and porous Si. First, it remains a challenge to create energetic materials, a mixture of Al and metal oxides, with nanoscale uniformity. Here, we report synthesis and ignition studies on thermites (mixtures of Al and metal oxides) with unique nanostructures, i.e., CuO/Al core/shell nanowires (NWs) and Al/CuO core/shell micro and nano particles. The CuO NW cores were synthesized by the thermal annealing of copper films and served as templates for the deposition of Al shells by subsequent sputtering. Similarly, for core/shell particles, the Al particles were coated with a very thin CuO shell using a solution phase method. The advantage of such core/shell structures are that CuO and Al are uniformly mixed at the nanoscale with no aggregation. The onset temperatures of the exothermic reaction of the core/shell NWs were similar to those of nanoparticle NP-based thermites in terms of magnitude, and insensitivity to equivalence ratios. Moreover, the core/shell NW thermites, compared to NP-based thermites, exhibit greatly improved mixing uniformity and reduced activation energy for the thermite reaction. For Al/CuO core/shell particles, in comparison to mixtures of Al particles and CuO NPs, have better chemical homogeneity and physical contact between Al and CuO, so that the core/shell particles exhibit much larger burning rates. The core/shell structure is a general and effective structure to tailor the combustion performance of energetic materials. Second, nonintrusive optical flash ignition is attractive for many applications due to its simplicity, and flexibility in controlling the area exposed to the flash. However, the oxidation mechanism of Al NPs at large heating rates remains inconclusive due to the lack of direct experimental evidence. We studied the oxidation mechanism of Al NPs under large heating rate (on the order of 106 K/s or higher) by a simple flash ignition method, which uses a xenon flash to ignite Al NPs. The flash ignition occurs when the Al NPs have suitable diameters and sufficient packing density to increase the temperature above their ignition temperatures. We then extended the flash ignition to Al MPs. Flash ignition of Al MPs is challenging due to their higher minimum flash ignition energy, which originates from weaker light absorption and higher ignition temperature compared to Al NPs. By the addition of WO3 NPs to Al MPs, the minimum flash ignition energy of Al MPs was reduced and we studied the roles of WO3 NPs upon flash ignition. Finally, we demonstrate that freestanding porous Si films can also be optically ignited in ambient air by a xenon flash. Our complementary experimental and numerical studies reveal that the minimum flash ignition energy increases with increasing the thickness due to heat loss through the porous Si layer. The minimum flash ignition energy is lower for higher porosity Si film since higher porosity reduces the heat capacity and thermal conductivity, facilitating the temperature rise. We believe that these results will be of great importance to reliably ignite energetic materials and to prevent unwanted combustion for practical energetic applications.
Download or read book Enhancing the Ignition and Combustion Performance of Metal based Energetic Materials written by Sindy K.Y. Tang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Energetic materials consisting of a fuel and oxidizer are capable of rapidly releasing large amounts of energy through their redox reaction. These materials have a broad range of applications ranging from solid rocket propellants and explosives to heat generators. Metal (e.g., silicon (Si), boron (B), and aluminum (Al))-based energetic materials are attractive due to their high volumetric and gravimetric energy densities. However, these materials exhibit slow energy release rates and are difficult to ignite, preventing them from being leveraged for their superior energy densities in these applications. In this dissertation, three approaches are developed for lowering the ignition threshold and improving the energy release rates of metal-based energetic materials. One approach utilizes the optical flash ignition method which can achieve distributed ignition of energetic materials to reduce ignition threshold and enhance energy release rates. Another approach is to add a metal oxide that supplies additional oxygen to improve oxygen diffusion rates to the fuel so to enhance energy release rates. Finally, creating a unique core/shell nanostructure increases intimate contact, along with a modified micro-emulsion method reduces particle agglomeration, increasing the energy release rates of metal-based energetic materials. First, the optical flash ignition of Si particles is examined, and complementary experimental and numerical studies unveil the impact of particle size and porosity on the ignition properties. Furthermore, a sensitivity analysis is presented, which details the role of the porosity of the Si particle bed in reducing the minimum radiant fluence for ignition. Five common metal oxides (CuO, Bi2O3, MoO3, Co3O4, and Fe2O3) are then surveyed as candidate oxidizers for improving the combustion characteristics of Boron particles, and it is found that binary oxide mixtures (CuO + Bi2O3) are more effective at promoting combustion characteristics of B particles than a single metal oxide. Though these metal oxide mixtures substantially improve the combustion performance of metal fuels, challenges in obtaining homogeneous mixtures and interfacial contact between fuels and oxidizers are prevalent. As a potential solution, we report synthesis and ignition studies of fuel and metal oxide systems (Si/Fe2O3) with a unique core/shell structure, which drastically lowers the ignition threshold compared to the traditionally mechanically mixed Si/Fe2O3. Finally, a modified micro-emulsion method is detailed here, which incorporates particle surface functionalization and pre-dispersion to achieve uniform distribution and contact between an aluminum fuel and polyvinylidene fluoride oxidizer (Al/PVDF). The fluoro-based oxidizer provides an advantage of higher oxidation potential, but Al fuel typically suffers from substantial agglomeration within fluoro-based oxidizers. The novel modified micro-emulsion method was found to reduce ignition delay and improve combustion efficiency. These approaches are applicable in preparing diverse metal-based energetic materials to improve their ignition and combustion properties.
Download or read book Nano Energetic Materials written by Shantanu Bhattacharya and published by Springer. This book was released on 2018-11-09 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest research on the area of nano-energetic materials, their synthesis, fabrication, patterning, application and integration with various MEMS systems and platforms. Keeping in mind the applications for this field in aerospace and defense sectors, the articles in this volume contain contributions by leading researchers in the field, who discuss the current challenges and future perspectives. This volume will be of use to researchers working on various applications of high-energy research.
Download or read book Nanocomposites for Visible Light induced Photocatalysis written by Mohammad Mansoob Khan and published by Springer. This book was released on 2017-09-07 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book details the chemistry of visible light-induced photocatalysis using different classes of nanocomposites. Starting with a general introduction and explanation of basic principles and mechanisms of (visible) light-induced photocatalysis in the first two chapters (not omitting a plaidoyer for furthering research and development in this promising field), the following chapters detail the different types and classes of nanocomposites currently used in light-induced photocatalytic applications, including e.g. metal and mixed metal-oxide nanoparticles and –composites, nanoporous materials, polymeric and carbon-based nanocomposites. They explain the characteristics and importance of the different types of nanocomposites, as well as their synthesis and fabrication.In the end of the book an outlook on the unique applications of novel nanocomposites is offered, for example in water treatment and disinfection and removal of pollutants from wastewater, self-cleaning window panes based on photoactive materials, and many more. The book also addresses the challenges in present photocatalytic research, and therefore is a must-read for everybody interested in the developing field of nanocomposites and visible light-induced photocatalysis.
Download or read book Nanoscale Materials written by Luis M. Liz-Marzán and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organized nanoassemblies of inorganic nanoparticles and organic molecules are building blocks of nanodevices, whether they are designed to perform molecular level computing, sense the environment or improve the catalytic properties of a material. The key to creation of these hybrid nanostructures lies in understanding the chemistry at a fundamental level. This book serves as a reference book for researchers by providing fundamental understanding of many nanoscopic materials.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energetic Nanomaterials written by Vladimir E Zarko and published by Elsevier. This book was released on 2016-01-21 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energetic Nanomaterials: Synthesis, Characterization, and Application provides researchers in academia and industry the most novel and meaningful knowledge on nanoenergetic materials, covering the fundamental chemical aspects from synthesis to application. This valuable resource fills the current gap in book publications on nanoenergetics, the energetic nanomaterials that are applied in explosives, gun and rocket propellants, and pyrotechnic devices, which are expected to yield improved properties, such as a lower vulnerability towards shock initiation, enhanced blast, and environmentally friendly replacements of currently used materials. The current lack of a systematic and easily available book in this field has resulted in an underestimation of the input of nanoenergetic materials to modern technologies. This book is an indispensable resource for researchers in academia, industry, and research institutes dealing with the production and characterization of energetic materials all over the world. Written by high-level experts in the field of nanoenergetics Covers the hot topic of energetic nanomaterials, including nanometals and their applications in nanoexplosives Fills a gap in energetic nanomaterials book publications
Download or read book Chemistry of Nanocrystalline Oxide Materials written by K. C. Patil and published by World Scientific. This book was released on 2008 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nano-oxide materials lend themselves to applications in a wide variety of emerging technological fields such as microelectronics, catalysts, ceramics, coatings, and energy storage. However, developing new routes for making nano-based materials is a challenging area for solid-state materials chemists. This book does just that by describing a novel method for preparing them. The authors have developed a novel low-temperature, self-propagating synthetic route to nano-oxides by the solution combustion and combustible precursor processes. This method provides the desired composition, structure, and properties for many types of technologically useful nanocrystalline oxide materials like alumina, ceria, iron oxides, titania, yttria, and zirconia, among others.The book is particularly instructive in bringing readers one step closer to the exploration of nanomaterials. Students of nanoscience can acquaint themselves with the actual production and evaluation of nanopowders by this route, while academic researchers and industrial scientists will find answers to a host of questions on nano-oxides. The book also provides an impetus for scientists in industrial research to evaluate and explore new ways to scale up the production of nanomaterials, offering helpful suggestions for further research.
Download or read book Comprehensive Energy Systems written by Ibrahim Dincer and published by Elsevier. This book was released on 2018-02-07 with total page 5543 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Energy Systems, Seven Volume Set provides a unified source of information covering the entire spectrum of energy, one of the most significant issues humanity has to face. This comprehensive book describes traditional and novel energy systems, from single generation to multi-generation, also covering theory and applications. In addition, it also presents high-level coverage on energy policies, strategies, environmental impacts and sustainable development. No other published work covers such breadth of topics in similar depth. High-level sections include Energy Fundamentals, Energy Materials, Energy Production, Energy Conversion, and Energy Management. Offers the most comprehensive resource available on the topic of energy systems Presents an authoritative resource authored and edited by leading experts in the field Consolidates information currently scattered in publications from different research fields (engineering as well as physics, chemistry, environmental sciences and economics), thus ensuring a common standard and language
Download or read book Combustion Synthesis Novel Routes to Novel Materials written by Maximilian Lackner and published by Bentham Science Publishers. This book was released on 2010-07-08 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion Synthesis covers a wide range of technologies to produce advanced materials, ranging from oxides, nitrides and intermetallics to various nanostructured compounds, such as nanopowders and carbon nano tubes (CNT). This Ebook, with contributions from leading experts in industry and academia, provides an up-to-date overview about combustion synthesis. a comparison to conventional methods as well as a description of analytical techniques is given, alongside the description of special techniques, such as microwave or electrical field assistance. Aspects such as historic development and scale-up make this book a concise, yet comprehensive review about combustion synthesis. This book should be useful for scientists, engineers and practitioners working in materials science and related fields.
Download or read book Chemical Rocket Propulsion written by Luigi T. De Luca and published by Springer. This book was released on 2016-08-19 with total page 1069 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developed and expanded from the work presented at the New Energetic Materials and Propulsion Techniques for Space Exploration workshop in June 2014, this book contains new scientific results, up-to-date reviews, and inspiring perspectives in a number of areas related to the energetic aspects of chemical rocket propulsion. This collection covers the entire life of energetic materials from their conceptual formulation to practical manufacturing; it includes coverage of theoretical and experimental ballistics, performance properties, as well as laboratory-scale and full system-scale, handling, hazards, environment, ageing, and disposal. Chemical Rocket Propulsion is a unique work, where a selection of accomplished experts from the pioneering era of space propulsion and current technologists from the most advanced international laboratories discuss the future of chemical rocket propulsion for access to, and exploration of, space. It will be of interest to both postgraduate and final-year undergraduate students in aerospace engineering, and practicing aeronautical engineers and designers, especially those with an interest in propulsion, as well as researchers in energetic materials.
Download or read book Properties and Applications of Silicon Carbide written by Rosario Gerhardt and published by BoD – Books on Demand. This book was released on 2011-04-04 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, we explore an eclectic mix of articles that highlight some new potential applications of SiC and different ways to achieve specific properties. Some articles describe well-established processing methods, while others highlight phase equilibria or machining methods. A resurgence of interest in the structural arena is evident, while new ways to utilize the interesting electromagnetic properties of SiC continue to increase.
Download or read book Energy a Continuing Bibliography with Indexes written by and published by . This book was released on 1983 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combustion for Material Synthesis written by Alexander S. Rogachev and published by CRC Press. This book was released on 2014-12-15 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the state of the art in combustion synthesis of advanced materials. It is a first attempt to summarize and critically review in one monograph the mechanisms of combustion and product structure formation for a variety of systems, including nanosystems. The authors discuss a wide range of topics including phenomenology, theory, and modern in-situ experimental approaches to investigate the heterogeneous self-sustained reactions, as well as properties of the product synthesized, and methods for large-scale materials production.
Download or read book Mechanical Alloying And Milling written by Cury Suryanarayana and published by CRC Press. This book was released on 2004-09-28 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book surveys the broad field of mechanical alloying from a scientific and technological perspective to form a timely and comprehensive resource valuable to both students and researchers. The treatment progresses from the historical background through a description of the process, the different metastable effects produced, and the mechanisms of
Download or read book U S Government Research Reports written by and published by . This book was released on 1962 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methanol The Basic Chemical and Energy Feedstock of the Future written by Martin Bertau and published by Springer Science & Business Media. This book was released on 2014-02-18 with total page 699 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methanol - The Chemical and Energy Feedstock of the Future offers a visionary yet unbiased view of methanol technology. Based on the groundbreaking 1986 publication "Methanol" by Friedrich Asinger, this book includes contributions by more than 40 experts from industry and academia. The authors and editors provide a comprehensive exposition of methanol chemistry and technology which is useful for a wide variety of scientists working in chemistry and energy related industries as well as academic researchers and even decision-makers and organisations concerned with the future of chemical and energy feedstocks.
