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Sample records for nanostructured energetic materials

  1. Nanostructured Energetic Materials with Sol-Gel Methods

    Energy Technology Data Exchange (ETDEWEB)

    Gash, A; Satcher, J; Simpson, R; Clapsaddle, B

    2003-11-25

    The utilization of sol-gel chemical methodology to prepare nanostructured energetic materials as well as the concepts of nanoenergetics is described. The preparation and characterization of two totally different compositions is detailed. In one example, nanostructured aerogel and xerogel composites of sol-gel iron (III) oxide and ultra fine grained aluminum (UFG Al) are prepared, characterized, and compared to a conventional micron-sized Fe{sub 2}O{sub 3}/Al thermite. The exquisite degree of mixing and intimate nanostructuring of this material is illustrated using transmission and scanning electron microscopies (TEM and SEM). The nanocomposite material has markedly different energy release (burn rate) and thermal properties compared to the conventional composite, results of which will be discussed. Small-scale safety characterization was performed aerogels and xerogels of the nanostructured thermite. The second nanostructured energetic material consists of a nanostructured hydrocarbon resin fuel network with fine ammonium perchlorate (NH{sub 4}ClO{sub 4}) oxidizer present.

  2. Nanostructured energetic materials derived from sol-gel chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, R L; Tillotson, T M; Hrubesh, L W; Gash, A E

    2000-03-15

    Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocrystalline ammonium perchlorate, the oxidizer, trapped within its pores. At optimum stoichiometry it has approximately the energy density of HMX. Transmission electron microscopy indicated no ammonium perchlorate crystallites larger than 20 nm while near-edge soft x-ray absorption microscopy showed that nitrogen was uniformly distributed, at least on the scale of less than 80 nm. Small-angle neutron scattering studies were conducted on the material. Those results were consistent with historical ones for this class of nanostructured materials. The average skeletal primary particle size was on the order of 2.7 nm, while the nanocomposite showed the growth of small 1 nm size crystals of ammonium perchlorate with some clustering to form particles greater than 10 nm.

  3. Preparation and reactivity of gasless nanostructured energetic materials.

    Science.gov (United States)

    Manukyan, Khachatur V; Shuck, Christopher E; Rogachev, Alexander S; Mukasyan, Alexander S

    2015-04-02

    High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites.

  4. Nanostructured energetic materials using sol-gel methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Tillotson, T M; Simpson, R L; Hrubesh, L W; Gash, A E; Thomas, I M; Poco, J F

    2000-09-27

    The fundamental differences between energetic composites and energetic materials made from a monomolecular approach are the energy density attainable and the energy release rates. For the past 4 years, we have been exploiting sol-gel chemistry as a route to process energetic materials on a microstructural scale. At the last ISA conference, we described four specific sol-gel approaches to fabricating energetic materials and presented our early work and results on two methods - solution crystallization and powder addition. Here, we detail our work on a third approach, energetic nanocomposites. Synthesis of thermitic types of energetic nanocomposites are presented using transition and main group metal-oxide skeletons. Results on characterization of structure and performance will also be given.

  5. Complex Nanostructures: Synthesis and Energetic Applications

    OpenAIRE

    Dunwei Wang; Stafford Sheehan; Sa Zhou; Yongjing Lin; Xiaohua Liu

    2010-01-01

    Connected through single crystalline junctions, low dimensional materials such as nanowires and nanorods form complex nanostructures. These new materials exhibit mechanical strengths and electrical conductivities superior to their constituents while maintaining comparable surface areas, an attribute ideal for energetic applications. More efficient solar cells, higher capacity batteries and better performing photoelectrochemical cells have been built using these materials. This article reviews...

  6. Electrostatic interactions for directed assembly of high performance nanostructured energetic materials of Al/Fe{sub 2}O{sub 3}/multi-walled carbon nanotube (MWCNT)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tianfu; Ma, Zhuang; Li, Guoping; Wang, Zhen; Zhao, Benbo; Luo, Yunjun, E-mail: yjluo@bit.edu.cn

    2016-05-15

    Electrostatic self-assembly in organic solvent without intensively oxidative or corrosive environments, was adopted to prepare Al/Fe{sub 2}O{sub 3}/MWCNT nanostructured energetic materials as an energy generating material. The negatively charged MWCNT was used as a glue-like agent to direct the self-assembly of the well dispersed positively charged Al (fuel) and Fe{sub 2}O{sub 3} (oxide) nanoparticles. This spontaneous assembly method without any surfactant chemistry or other chemical and biological moieties decreased the aggregation of the same nanoparticles largely, moreover, the poor interfacial contact between the Al (fuel) and Fe{sub 2}O{sub 3} (oxide) nanoparticles was improved significantly, which was the key characteristic of high performance nanostructured energetic materials. In addition, the assembly process was confirmed as Diffusion-Limited Aggregation. The assembled Al/Fe{sub 2}O{sub 3}/MWCNT nanostructured energetic materials showed excellent performance with heat release of 2400 J/g, peak pressure of 0.42 MPa and pressurization rate of 105.71 MPa/s, superior to that in the control group Al/Fe{sub 2}O{sub 3} nanostructured energetic materials prepared by sonication with heat release of 1326 J/g, peak pressure of 0.19 MPa and pressurization rate of 33.33 MPa/s. Therefore, the approach, which is facile, opens a promising route to the high performance nanostructured energetic materials. - Graphical abstract: The negatively charged MWCNT was used as a glue-like agent to direct the self-assembly of the well dispersed positively charged Al (fuel) and Fe{sub 2}O{sub 3} (oxide) nanoparticles. - Highlights: • A facile spontaneous electrostatic assembly strategy without surfactant was adopted. • The fuels and oxidizers assembled into densely packed nanostructured composites. • The assembled nanostructured energetic materials have excellent performance. • This high performance energetic material can be scaled up for practical application. • This

  7. One-pot synthesis of interpenetrating inorganic/organic networks of CuO/resorcinol-formaldehyde aerogels: nanostructured energetic materials.

    Science.gov (United States)

    Leventis, Nicholas; Chandrasekaran, Naveen; Sadekar, Anand G; Sotiriou-Leventis, Chariklia; Lu, Hongbing

    2009-04-01

    For many applications ranging from catalysis to sensors to energetic materials, it is desirable to produce intimate mixtures of nanoparticles. For instance, to improve the reaction rates of energetic materials, the oxidizing agent and the fuel need to be mixed as intimately as possible, ideally at the nanoscopic level. In this context, the acidity of a hydrated CuCl(2) solution reacting toward a network of CuO nanoparticles (a good oxidant) is used to induce one-pot cogelation of a nanostructured network of a resorcinol-formaldehyde resin (RF, the fuel). The resulting wet gels are dried to aerogels, and upon pyrolysis under Ar, the interpenetrating CuO/RF network undergoes a smelting reaction toward metallic Cu. Upon ignition in the open air, pure RF aerogels do not burn, while CuO/RF composites, even with substoichiometric CuO, sustain combustion, burning completely leaving only a solid residue of CuO whose role then has been that of a redox mediator through the smelting reaction.

  8. Complex Nanostructures: Synthesis and Energetic Applications

    Directory of Open Access Journals (Sweden)

    Dunwei Wang

    2010-02-01

    Full Text Available Connected through single crystalline junctions, low dimensional materials such as nanowires and nanorods form complex nanostructures. These new materials exhibit mechanical strengths and electrical conductivities superior to their constituents while maintaining comparable surface areas, an attribute ideal for energetic applications. More efficient solar cells, higher capacity batteries and better performing photoelectrochemical cells have been built using these materials. This article reviews this exciting new class of materials and covers topics from controlled syntheses to applications in photovoltaics, chemical energy conversion and electrical charge storage. Mechanisms responsible for the improved performance are discussed. The prospect of their applications in a broader energy-related field is analyzed.

  9. Nanostructured Materials

    Science.gov (United States)

    2012-08-30

    with macroscopic reinforcements such as fiber, clay, glass mineral and other fillers. The nano-alloyed polymers are particularly useful for producing...applications, including space-sur- vivable materials and seals, gaskets, cosmetics , and personal care. 25 Claims, 10 Drawing Sheets B-3 U.S. Patent Mar...the incorporation of fluorinated nanostructured chemicals onto the surface of a secondary material (such as Ti02 , CaC03 , glass or mineral

  10. Nanostructured energetic composites: synthesis, ignition/combustion modeling, and applications.

    Science.gov (United States)

    Zhou, Xiang; Torabi, Mohsen; Lu, Jian; Shen, Ruiqi; Zhang, Kaili

    2014-03-12

    Nanotechnology has stimulated revolutionary advances in many scientific and industrial fields, particularly in energetic materials. Powder mixing is the simplest and most traditional method to prepare nanoenergetic composites, and preliminary findings have shown that these composites perform more effectively than their micro- or macro-sized counterparts in terms of energy release, ignition, and combustion. Powder mixing technology represents only the minimum capability of nanotechnology to boost the development of energetic material research, and it has intrinsic limitations, namely, random distribution of fuel and oxidizer particles, inevitable fuel pre-oxidation, and non-intimate contact between reactants. As an alternative, nanostructured energetic composites can be prepared through a delicately designed process. These composites outperform powder-mixed nanocomposites in numerous ways; therefore, we comprehensively discuss the preparation strategies adopted for nanostructured energetic composites and the research achievements thus far in this review. The latest ignition and reaction models are briefly introduced. Finally, the broad promising applications of nanostructured energetic composites are highlighted.

  11. NANOSTRUCTURE PATTERNING UNDER ENERGETIC PARTICLE BEAM IRRADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lumin [Regents of the University of Michigan; Lu, Wei [Regents of the University of Michigan

    2013-01-31

    Energetic ion bombardment can lead to the development of complex and diverse nanostructures on or beneath the material surface through induced self-organization processes. These self-organized structures have received particular interest recently as promising candidates as simple, inexpensive, and large area patterns, whose optical, electronic and magnetic properties are different from those in the bulk materials [1-5]. Compared to the low mass efficiency production rate of lithographic methods, these self-organized approaches display new routes for the fabrication of nanostructures over large areas in a short processing time at the nanoscale, beyond the limits of lithography [1,4]. Although it is believed that surface nanostructure formation is based on the morphological instability of the sputtered surface, driven by a kinetic balance between roughening and smoothing actions [6,7], the fundamental mechanisms and experimental conditions for the formation of these nanostructures has still not been well established, the formation of the 3-D naopatterns beneath the irradiated surface especially needs more exploration. During the last funding period, we have focused our efforts on irradiation-induced nanostructures in a broad range of materials. These structures have been studied primarily through in situ electron microscopy during electron or ion irradiation. In particular, we have performed studies on 3-D void/bubble lattices (in metals and CaF2), embedded sponge-like porous structure with uniform nanofibers in irradiated semiconductors (Ge, GaSb, and InSb), 2-D highly ordered pattern of nanodroplets (on the surface of GaAs), hexagonally ordered nanoholes (on the surface of Ge), and 1-D highly ordered ripple and periodic arrays (of Cu nanoparticles) [3,8-11]. The amazing common feature in those nanopatterns is the uniformity of the size of nanoelements (nanoripples, nanodots, nanovoids or nanofibers) and the distance separating them. Our research focuses on the

  12. Bulk Nanostructured Materials

    Science.gov (United States)

    Koch, C. C.; Langdon, T. G.; Lavernia, E. J.

    2017-09-01

    This paper will address three topics of importance to bulk nanostructured materials. Bulk nanostructured materials are defined as bulk solids with nanoscale or partly nanoscale microstructures. This category of nanostructured materials has historical roots going back many decades but has relatively recent focus due to new discoveries of unique properties of some nanoscale materials. Bulk nanostructured materials are prepared by a variety of severe plastic deformation methods, and these will be reviewed. Powder processing to prepare bulk nanostructured materials requires that the powders be consolidated by typical combinations of pressure and temperature, the latter leading to coarsening of the microstructure. The thermal stability of nanostructured materials will also be discussed. An example of bringing nanostructured materials to applications as structural materials will be described in terms of the cryomilling of powders and their consolidation.

  13. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  14. The role of energetic ions from plasma in the creation of nanostructured materials and stable polymer surface treatments

    Energy Technology Data Exchange (ETDEWEB)

    Bilek, M.M.M. [Department of Applied and Plasma Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)]. E-mail: mmmb@physics.usyd.edu.au; Newton-McGee, K. [Department of Applied and Plasma Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); McKenzie, D.R. [Department of Applied and Plasma Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); McCulloch, D.G. [Department of Applied and Plasma Physics, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

    2006-01-15

    Plasma processes for the synthesis of new materials as thin films have enabled the production of a wide variety of new materials. These include meta-stable phases, which are not readily found in nature, and more recently, materials with structure on the nanoscale. Study of plasma synthesis processes at the fundamental level has revealed that ion energy, depositing flux and growth surface temperature are the critical parameters affecting the microstructure and the properties of the thin film materials formed. In this paper, we focus on the role of ion flux and impact energy in the creation of thin films with nanoscale structure in the form of multilayers. We describe three synthesis strategies, based on the extraction of ions from plasma sources and involving modulation of ion flux and ion energy. The microstructure, intrinsic stress and physical properties of the multilayered samples synthesized are studied and related back to the conditions at the growth surface during deposition. When energetic ions of a non-condensing species are used, it is possible to place active groups on the surfaces of materials such as polymers. These active groups can then be used as bonding sites in subsequent chemical attachment of proteins or other macromolecules. If the energy of the non-condensing ions is increased to a few keV then modified layers buried under the surface can be produced. Here we describe a method by which the aging effect, which is often observed in plasma surface modifications on polymers, can be reduced and even eliminated using high energy ion bombardment.

  15. Nanostructured Materials for Magnetoelectronics

    CERN Document Server

    Mikailzade, Faik

    2013-01-01

    This book provides an up-to-date review of nanometer-scale magnetism and focuses on the investigation of the basic properties of magnetic nanostructures. It describes a wide range of physical aspects together with theoretical and experimental methods. A broad overview of the latest developments in this emerging and fascinating field of nanostructured materials is given with emphasis on the practical understanding and operation of submicron devices based on nanostructured magnetic materials.

  16. Nanostructured electronic and magnetic materials

    Indian Academy of Sciences (India)

    R V Ramanujan

    2003-02-01

    Research and development in nanostructured materials is one of the most intensely studied areas in science. As a result of concerted R & D efforts, nanostructured electronic and magnetic materials have achieved commercial success. Specific examples of novel industrially important nanostructured electronic and magnetic materials are provided. Advantages of nanocrystalline magnetic materials in the context of both materials and devices are discussed. Several high technology examples of the use of nanostructured magnetic materials are presented. Methods of processing nanostructured materials are described and the examples of sol gel, rapid solidification and powder injection moulding as potential processing methods for making nanostructured materials are outlined. Some opportunities and challenges are discussed.

  17. Nanostructured materials in potentiometry.

    Science.gov (United States)

    Düzgün, Ali; Zelada-Guillén, Gustavo A; Crespo, Gastón A; Macho, Santiago; Riu, Jordi; Rius, F Xavier

    2011-01-01

    Potentiometry is a very simple electrochemical technique with extraordinary analytical capabilities. It is also well known that nanostructured materials display properties which they do not show in the bulk phase. The combination of the two fields of potentiometry and nanomaterials is therefore a promising area of research and development. In this report, we explain the fundamentals of potentiometric devices that incorporate nanostructured materials and we highlight the advantages and drawbacks of combining nanomaterials and potentiometry. The paper provides an overview of the role of nanostructured materials in the two commonest potentiometric sensors: field-effect transistors and ion-selective electrodes. Additionally, we provide a few recent examples of new potentiometric sensors that are based on receptors immobilized directly onto the nanostructured material surface. Moreover, we summarize the use of potentiometry to analyze processes involving nanostructured materials and the prospects that the use of nanopores offer to potentiometry. Finally, we discuss several difficulties that currently hinder developments in the field and some future trends that will extend potentiometry into new analytical areas such as biology and medicine.

  18. Nanostructured materials for hydrogen storage

    Science.gov (United States)

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  19. Shock Sensitivity of energetic materials

    Science.gov (United States)

    Kim, K.

    1980-01-01

    Viscoplastic deformation is examined as the principal source of hot energy. Some shock sensitivity data on a proposed model is explained. A hollow sphere model is used to approximate complex porous matrix of energetic materials. Two pieces of shock sensitivity data are qualitatively compared with results of the proposed model. The first is the p2 tau law. The second is the desensitization of energetic materials by a ramp wave applied stress. An approach to improve the model based on experimental observations is outlined.

  20. Energetic materials at extreme conditions

    Energy Technology Data Exchange (ETDEWEB)

    Millar, David I.A. [Edinburgh Univ. (United Kingdom). EaStCHEM Research School of Chemistry

    2012-07-01

    This thesis describes the high-pressure structural behaviour of a series of energetic compounds that includes the widely used explosive RDX and gas generators such as sodium azide. Using a combination of X-ray and neutron diffraction techniques, crystal structures of these compounds have been obtained under conditions of elevated pressure and temperature. Such studies present significant technical challenges associated with both data collection and analysis, especially for compounds containing conformationally flexible molecules, but the structural information obtained is crucial for enhancing the understanding of the characteristics of energetic materials. Particularly significant is the observation that a high-pressure, high-temperature form of RDX may be recovered to ambient pressure. This has implications for the discovery of new forms of energetic materials that may exhibit enhanced properties, e.g. reduced sensitivity to accidental initiation. The rich high-pressure behaviour of the simple inorganic azides is also noteworthy. All of the six compounds studied in this work were found to undergo at least one phase transition and a total of ten polymorphs have been identified at variable pressure and/or temperature. For example, at high pressure sodium azide adopts the same structure observed for the larger alkali metal azides at atmospheric conditions. The first two chapters of this thesis provide a very accessible introduction to high-pressure research and energetic materials. The subsequent chapters detail the results of these high-pressure studies of energetic materials, demonstrating excellent clarity of expression and highly developed critical analysis. The final chapter points clearly to future opportunities for extending these studies to other energetic materials and for alternative methodologies for their structural modification. (orig.)

  1. Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Gash, A; Pantoya, M; Jr., J S; Zhao, L; Shea, K; Simpson, R; Clapsaddle, B

    2003-11-18

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Furthermore, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. As a result, the desired organic functionality is well dispersed throughout the composite material on the nanoscale. By introducing a fuel metal into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of these metal oxide/silicon oxide nanocomposites and their performance as energetic materials will be discussed.

  2. Preparation and characterization of GA/RDX nanostructured energetic composites

    Indian Academy of Sciences (India)

    YUANFEI LAN; XUEBAO WANG; YUNJUN LUO

    2016-12-01

    Graphene aerogel (GA) with nano-porous structure was assembled through the formation of physical cross-links between graphene sheets by a facile sol–gel method and supercritical CO$_2$ drying process. Thenhexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was added and trapped in the nano-porous three-dimensional networks of GA to obtain a novel GA/RDX nanostructured energetic composite. The composition, morphology andstructure of the obtained GA/RDX nanostructured energetic composite were characterized by elemental analysis, scanning electron microscopy, nitrogen sorption tests and X-ray diffraction. Moreover, the thermal decompositioncharacteristic was investigated by thermogravimetry and differential scanning calorimetry. The results showed that GA could be a perfect aerogel matrix for the fabrication of GA/RDX nanostructured energetic composite due to itsunique nano-porous structure and attributes. It was also demonstrated that RDX homogeneously disperses in the asprepared GA/RDX nanostructured energetic composite at nanometric scale. GA showed promising catalytic effects for the thermal decomposition of RDX. After incorporating with GA, the decomposition of RDX was obviously accelerated.

  3. Nano Engineered Energetic Materials (NEEM)

    Science.gov (United States)

    2011-01-12

    reactivity of the nitro group. The more perpendicular orientation of the NO2 in p- NBA leaves both oxygen atoms available to complex vapor deposited Al...different solutes have been recorded in supercritical CO2 in the past, the information on the solubility of many energetic materials including RDX is...The pH level of the solution was monitored before and after to record the ionic activity of the solution. Different amounts of dispersant and

  4. Energetic materials research using scanning electron microscopy

    NARCIS (Netherlands)

    Elshout, J.J.M.H. van den; Duvalois, W.; Benedetto, G.L. Di; Bouma, R.H.B.; Heijden, A.E.D.M. van der

    2016-01-01

    A key-technique for the research of energetic materials is scanning electron microscopy. In this paper several examples are given of characterization studies on energetic materials, including a solid composite propellant formulation. Results of the characterization of energetic materials using scann

  5. Energetic materials research using scanning electron microscopy

    NARCIS (Netherlands)

    Elshout, J.J.M.H. van den; Duvalois, W.; Benedetto, G.L. Di; Bouma, R.H.B.; Heijden, A.E.D.M. van der

    2016-01-01

    A key-technique for the research of energetic materials is scanning electron microscopy. In this paper several examples are given of characterization studies on energetic materials, including a solid composite propellant formulation. Results of the characterization of energetic materials using

  6. Nanoporous Silicon Based Energetic Materials

    Science.gov (United States)

    2008-12-01

    performed at SINTEF , Norway as shown in Figure 4 (line a). 3 Annealing PSi in air at different temperatures can be used to change the surface...3h (c)PSi annealed at 500C for 0.5 h (courtesy SINTEF ) e is C d magnification bright field TEM image of PSi-Fe2O3. The inset electron...Dr. Knut Thorshaug and Dr Diplos Spyros of SINTEF Norway for DRIFTS and XPS data. REFERENCES dvanced Energetics Materials, 2004; report byA ring

  7. Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Clapsaddle, B; Gash, A; Plantier, K; Pantoya, M; Jr., J S; Simpson, R

    2004-04-27

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. By introducing a fuel metal, such as aluminum, into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. In addition, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. These organic additives can cause the generation of gas upon ignition of the materials, therefore resulting in a composite material that can perform pressure/volume work. Furthermore, the desired organic functionality is well dispersed throughout the composite material on the nanoscale with the other components, and is therefore subject to the same increased reaction kinetics. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of iron(III) oxide/organosilicon oxide nanocomposites and their performance as energetic materials will be discussed.

  8. Femtosecond Laser Interaction with Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E; Benterou, J; Lee, R; Roeske, F; Stuart, B

    2002-03-25

    Femtosecond laser ablation shows promise in machining energetic materials into desired shapes with minimal thermal and mechanical effects to the remaining material. We will discuss the physical effects associated with machining energetic materials and assemblies containing energetic materials, based on experimental results. Interaction of ultra-short laser pulses with matter will produce high temperature plasma at high-pressure which results in the ablation of material. In the case of energetic material, which includes high explosives, propellants and pyrotechnics, this ablation process must be accomplished without coupling energy into the energetic material. Experiments were conducted in order to characterize and better understand the phenomena of femtosecond laser pulse ablation on a variety of explosives and propellants. Experimental data will be presented for laser fluence thresholds, machining rates, cutting depths and surface quality of the cuts.

  9. Energetic materials and methods of tailoring electrostatic discharge sensitivity of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, Michael A.; Heaps, Ronald J.; Wallace, Ronald S.; Pantoya, Michelle L.; Collins, Eric S.

    2016-11-01

    An energetic material comprising an elemental fuel, an oxidizer or other element, and a carbon nanofiller or carbon fiber rods, where the carbon nanofiller or carbon fiber rods are substantially homogeneously dispersed in the energetic material. Methods of tailoring the electrostatic discharge sensitivity of an energetic material are also disclosed.

  10. Destruction of Energetic Materials in Supercritical Water

    Science.gov (United States)

    2002-06-25

    THERMOCHEMISTRY OF ENERGETIC MATERIALS IN SUPERCRITICAL WATER...fringe spacing is 13.5 µm and the acoustic signal period is 28.3 ns. 138 SECTION VI THERMOCHEMISTRY OF ENERGETIC MATERIALS IN...validation calculation studied the solvation free energies of alkali–chloride ion pairs in liquid water. Such information can teach us about the

  11. Safer energetic materials by a nanotechnological approach.

    Science.gov (United States)

    Siegert, Benny; Comet, Marc; Spitzer, Denis

    2011-09-01

    Energetic materials - explosives, thermites, populsive powders - are used in a variety of military and civilian applications. Their mechanical and electrostatic sensitivity is high in many cases, which can lead to accidents during handling and transport. These considerations limit the practical use of some energetic materials despite their good performance. For industrial applications, safety is one of the main criteria for selecting energetic materials. The sensitivity has been regarded as an intrinsic property of a substance for a long time. However, in recent years, several approaches to lower the sensitivity of a given substance, using nanotechnology and materials engineering, have been described. This feature article gives an overview over ways to prepare energetic (nano-)materials with a lower sensitivity.

  12. Nanostructured materials for thermoelectric applications.

    Science.gov (United States)

    Bux, Sabah K; Fleurial, Jean-Pierre; Kaner, Richard B

    2010-11-28

    Recent studies indicate that nanostructuring can be an effective method for increasing the dimensionless thermoelectric figure of merit (ZT) in materials. Most of the enhancement in ZT can be attributed to large reductions in the lattice thermal conductivity due to increased phonon scattering at interfaces. Although significant gains have been reported, much higher ZTs in practical, cost-effective and environmentally benign materials are needed in order for thermoelectrics to become effective for large-scale, wide-spread power and thermal management applications. This review discusses the various synthetic techniques that can be used in the production of bulk scale nanostructured materials. The advantages and disadvantages of each synthetic method are evaluated along with guidelines and goals presented for an ideal thermoelectric material. With proper optimization, some of these techniques hold promise for producing high efficiency devices.

  13. Nanostructured materials for water desalination

    Energy Technology Data Exchange (ETDEWEB)

    Humplik, T; Lee, J; O' Hern, S C; Fellman, B A; Karnik, R; Wang, E N [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge (United States); Baig, M A; Hassan, S F; Atieh, M A; Rahman, F; Laoui, T, E-mail: tlaoui@kfupm.edu.sa, E-mail: karnik@mit.edu, E-mail: enwang@mit.edu [Departments of Mechanical Engineering and Chemical Engineering and Research Institute, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2011-07-22

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity. (topical review)

  14. Nanostructured materials for water desalination

    Science.gov (United States)

    Humplik, T.; Lee, J.; O'Hern, S. C.; Fellman, B. A.; Baig, M. A.; Hassan, S. F.; Atieh, M. A.; Rahman, F.; Laoui, T.; Karnik, R.; Wang, E. N.

    2011-07-01

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

  15. Nanostructured materials for water desalination.

    Science.gov (United States)

    Humplik, T; Lee, J; O'Hern, S C; Fellman, B A; Baig, M A; Hassan, S F; Atieh, M A; Rahman, F; Laoui, T; Karnik, R; Wang, E N

    2011-07-22

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

  16. Composite materials formed with anchored nanostructures

    Science.gov (United States)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2015-03-10

    A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

  17. Method of fabrication of anchored nanostructure materials

    Science.gov (United States)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-11-26

    Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

  18. Nanostructured materials in electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Eftekhari, Ali (ed.) [Avicenna Institute of Technology, Cleveland, OH (United States)

    2008-07-01

    Providing the unique and vital link between the worlds of electrochemistry and nanomaterials, this reference and handbook covers advances in electrochemistry through the nanoscale control of electrode structures, as well as advances in nanotechnology through electrochemical synthesis strategies. It demonstrates how electrochemical methods are of great scientific and commercial interest due to their low cost and high efficiency, and includes the synthesis of nanowires, nanoparticles, nanoporous and layered nanomaterials of various compositions, as well as their applications - ranging from superior electrode materials to energy storage, biosensors, and electroanalytical devices. (orig.)

  19. Nanostructured conductive polymeric materials

    Science.gov (United States)

    Al-Saleh, Mohammed H.

    Conductive polymer composites (CPCs) are a suitable alternative to metals in many applications due to their light-weight, corrosion resistance, low cost, ease of processing and design flexibility. CPCs have been formulated using different types of conductive fillers. In this PhD thesis, the focus is on CPCs for electrostatic discharge (ESD) protection and electromagnetic interference (EMI) attenuation. Despite the versatility of conductive fillers, carbon black (CB) has been the dominant filler to make CPCs for ESD protection applications because CB/polymer composites have a cost advantage over all other CPCs. For EMI shielding, stainless steel fibres and metal coated fibers are the preferred fillers, however CPCs made of those fibers are not the dominant EMI shielding materials. Metal coated and polymer plated polymers are the most widely used EMI shielding options. The limited use of CPCs in the EMI shielding market is because the high filler loading required to formulate a composite with an adequate level of shielding remarkably increases the composite price. In order to increase the competitiveness of CPCs, percolation threshold should be minimized as much as possible and composites with high EMI shielding capabilities at low filler loading should be formulated because all conductive fillers are expensive compared to polymers. In this thesis, two different methodologies to reduce percolation threshold in CPCs have been successfully developed and a CPC with exceptional EMI shielding capability has been formulated using copper nanowires as conductive filler. The first percolation threshold reduction technique is based on the selective localization of CB at the interface of immiscible polymer blend. The technique requires adding a copolymer that prefers the blend's interface and for which CB nanoparticles has the highest affinity. The second method is based on producing a CPC powder and then using this powder as a conductive filler to produce composite by dry

  20. Anchored nanostructure materials and method of fabrication

    Science.gov (United States)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2012-11-27

    Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

  1. Energy transfer in nanostructured materials

    Science.gov (United States)

    Haughn, Chelsea

    Energy transport and loss are critical to the performance of optoelectronic devices such as photovoltaics and terahertz imaging devices. Nanostructured materials provide many opportunities to tailor transport and loss parameters for specific device applications. However, it has been very difficult to correlate specific nanoscale structural parameters with changes in these performance metrics. I report the development of new ways of using time-resolved photoluminescence (TRPL) to probe charge and energy transport and loss dynamics. These techniques are applied to several types of nanostructured materials, including bulk semiconductors with defects, self-assembled quantum dots and colloidal quantum dots. First, GaAs/InP double heterostructures grown via metal organic chemical vapor deposition (MOCVD) were characterized with TRPL. TRPL is typically used to extract minority carrier lifetimes, but we discovered that the measured lifetime depended critically on the intensity of the exciting laser. We developed a Shockley-Read-Hall model to extract trap state densities from intensity-dependent TRPL measurements. Second, we characterized energy and charge transfer between InAs quantum dots and ErAs nanoinclusions within III-V heterostructures. Using intensity- and temperature-dependent TRPL, we confirmed tunneling as the dominant mechanism of charge transport and characterized the electronic structure of the ErAs nanoparticles. Finally, we characterized energy transport in colloidal quantum dot cascade structures. These cascade structures utilize Forster Resonance Energy Transfer and trap state recycling to funnel excitons from donor layers to acceptor layers and suggest a promising method for avoiding losses associated with surface trap states. Collectively, the analysis of these disparate material types advances our understanding of energy dynamics in nanostructured materials and improves our ability to design the next generation of photovoltaic and optoelectronic

  2. Quantitative Characterization of Nanostructured Materials

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Frank (Bud) Bridges, University of California-Santa Cruz

    2010-08-05

    The two-and-a-half day symposium on the "Quantitative Characterization of Nanostructured Materials" will be the first comprehensive meeting on this topic held under the auspices of a major U.S. professional society. Spring MRS Meetings provide a natural venue for this symposium as they attract a broad audience of researchers that represents a cross-section of the state-of-the-art regarding synthesis, structure-property relations, and applications of nanostructured materials. Close interactions among the experts in local structure measurements and materials researchers will help both to identify measurement needs pertinent to real-world materials problems and to familiarize the materials research community with the state-of-the-art local structure measurement techniques. We have chosen invited speakers that reflect the multidisciplinary and international nature of this topic and the need to continually nurture productive interfaces among university, government and industrial laboratories. The intent of the symposium is to provide an interdisciplinary forum for discussion and exchange of ideas on the recent progress in quantitative characterization of structural order in nanomaterials using different experimental techniques and theory. The symposium is expected to facilitate discussions on optimal approaches for determining atomic structure at the nanoscale using combined inputs from multiple measurement techniques.

  3. Nanostructured materials in electroanalysis of pharmaceuticals.

    Science.gov (United States)

    Rahi, A; Karimian, K; Heli, H

    2016-03-15

    Basic strategies and recent developments for the enhancement of the sensory performance of nanostructures in the electroanalysis of pharmaceuticals are reviewed. A discussion of the properties of nanostructures and their application as modified electrodes for drug assays is presented. The electrocatalytic effect of nanostructured materials and their application in determining low levels of drugs in pharmaceutical forms and biofluids are discussed.

  4. Amination of energetic anions: high-performing energetic materials.

    Science.gov (United States)

    Klapötke, Thomas M; Piercey, Davin G; Stierstorfer, Jörg

    2012-08-21

    The new energetic materials 2-amino-5-nitrotetrazole (ANT, 1), 1-amino-3,4-dinitro-1,2,4-triazole (ADNT, 2), and both 1,1'-diamino-5,5'-bistetrazole and 1,2'-diamino-5,5'-bistetrazole (11DABT, 3 and 12DABT, 4) have been prepared by the amination of the parent anion with O-tosylhydroxylamine. The 5-H-tetrazolate anion has also been aminated using hydroxylamine O-sulfonic acid to both 1-aminotetrazole and 2-aminotetrazole (1AT, 5 and 2AT, 6). The prepared materials have been characterized chemically (XRD (1-4, 6·AtNO(2), 8), multinuclear NMR, IR, Raman) and as explosives (mechanical and electrostatic sensitivity) and their explosive performances calculated using the EXPLO5 computer code. The prepared N-amino energetic materials, which can also be used as new ligands for high energy-capacity transition metal complexes, exhibit high explosive performances (in the range of hexogen and octogen) and a range of sensitivities from low to extremely high.

  5. Compatibility testing of energetic materials, which technique?

    NARCIS (Netherlands)

    Klerk, W.P.C. de; Schrader, M.A.; Steen, A.C. van der

    1999-01-01

    Compatibility is an important safety aspect related to the production and storage of energetic materials. To test different combinations of materials a simple test method with clear criteria is advisable. At the last ESTAC the use of microcalorimetry and the vacuum stability test for the

  6. Reapplication of energetic materials at fuels

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.; Sinquefield, S.; Huey, S.; Lipkin, J.; Shah, D.; Ross, J.; Sclippa, G. [Sandia National Labs., Livermore, CA (United States); Davis, K. [Reaction Engineering Internaional, Salt Lake City, UT (United States)

    1995-05-01

    This investigation addresses the combustion-related aspects of the reapplication of energetic materials as fuels in boilers as an economically viable and environmentally acceptable use of excess energetic materials. The economics of this approach indicate that the revenues from power generation and chemical recovery approximately equal the costs of boiler modification and changes in operation. The primary tradeoff is the cost of desensitizing the fuels against the cost of open burn/open detonation (OB/OD) or other disposal techniques. Two principal combustion-related obstacles to the use of energetic-material-derived fuels are NO{sub x} generation and the behavior of metals. NO{sub x} measurements obtained in this investigation indicate that the nitrated components (nitrocellulose, nitroglycerin, etc.) of energetic materials decompose with NO{sub x} as the primary product. This can lead to high uncontrolled NO{sub x} levels (as high as 2600 ppM on a 3% O{sub 2} basis for a 5% blend of energetic material in the fuel). NO{sub x} levels are sensitive to local stoichiometry and temperature. The observed trends resemble those common during the combustion of other nitrogen containing fuels. Implications for NO{sub x} control strategies are discussed. The behavior of inorganic components in energetic materials tested in this investigation could lead to boiler maintenance problems such as deposition, grate failure, and bed agglomeration. The root cause of the problem is the potentially extreme temperature generated during metal combustion. Implications for furnace selection and operation are discussed.

  7. Fluidjet machining of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sang-Wook; Reitter, T.; Carlson, G. [Lawrence Livermore National Lab., CA (United States); Do, B. [Mason and Hanger-Silas Mason Co., Inc., Amarillo, TX (United States)

    1994-01-01

    Fluidjet machining phenomena have been analyzed as a potential method for dismantling nuclear weapons in a way that is environmentally clean, efficient and safe. Preliminary experiments and analyses have revealed that at small standoff distances there is no mass removal from the workpiece, and that far from the nozzle there exists an optimum standoff distance at which the mass removal rate is a maximum. Such results suggest a mass-removal process due to the droplets and ligaments impinging on the material that cause sudden pressure increases in the impact regions. This proposed material-removal mechanism has been addressed theoretically by considering a series of multiple droplet impacts on a material. The calculated results display a series of pressure peaks at the target surface as each of these droplets strikes the material, supporting the plausibility of the proposed mass-removal scenario at the optimum standoff distance. Further experiments and analyses are planned to verify the proposed mechanism of mass removal by means of fluidjet machining processes.

  8. Energetic materials standards – Chemical compatibility

    NARCIS (Netherlands)

    Tuukkanen, I.M.; Bouma, R.H.B.

    2014-01-01

    Subgroup A Energetic Materials Team, SG/A (EMT), develops and maintains standards that are relevant to all life-cycle phases of ammunition/weapon systems. STANAG 4147 is the standard regarding chemical compatibility of explosives with munition components, and is a document of prime importance.

  9. Carbonyl-bridged energetic materials: biomimetic synthesis, organic catalytic synthesis, and energetic performances.

    Science.gov (United States)

    Feng, Yong-An; Qiu, Hao; Yang, Sa-Sha; Du, Jiang; Zhang, Tong-Lai

    2016-11-01

    In order to obtain high-performance energetic materials, in this work, carbonyl groups (C[double bond, length as m-dash]O) have been newly introduced as sole bridging groups in the field of energetic materials. To this end, two tailored green methods for the synthesis of carbonyl-bridged energetic compounds have been developed for the first time. One is a biomimetic synthesis, in which the conversion route of heme to biliverdin has been used to obtain metal-containing energetic compounds. The other one is an organocatalysis, in which guanidinium serves as an energetic catalyst to afford other energetic compounds. Experimental studies and theoretical calculations have shown that carbonyl-bridged energetic compounds exhibit excellent energetic properties, which is promising for the carbonyl group as a new important and effective linker in energetic materials.

  10. Sol-Gel Manufactured Energetic Materials

    Science.gov (United States)

    Simpson, Randall L.; Lee, Ronald S.; Tillotson, Thomas M.; Hrubesh, Lawrence W.; Swansiger, Rosalind W.; Fox, Glenn A.

    2005-05-17

    Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

  11. Formation of energetic materials using supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Teipel, U.; Kroeber, H.; Krause, H.H. [Fraunhofer-Institut fuer Chemische Technologie (ICT), Pfinztal (Germany)

    2001-10-01

    A new field of applications of compressed gases is the formation of solid particles with well-defined properties, e.g. the particle size, the particle size distribution, the particle shape, the specific surface area and free of solvent inclusions. It is possible to process moderately solids like energetic materials which are difficult to comminute due to their sensitivity to mechanical or thermal stress. The characteristics of compressed gases allow to vary the morphology of solid particles in a wide range. A pilot plant is presented, which has been built to prepare fine particles by the rapid expansion of supercritical solutions (RESS process) and precipitation by a compressed fluid antisolvent (PCA process). In this contribution the micronization of different energetic materials by the RESS and PCA processes will be under investigation. (orig.)

  12. Energetic oxygen atom material degradation studies

    Science.gov (United States)

    Caledonia, George E.; Krech, Robert H.

    1987-01-01

    As part of a study designed to test potential Shuttle surface materials for the extents of degradation and mass loss expected to be suffered in space from the velocity impacts of ambient oxygen atoms, a novel technique was developed for generation of a high flux of energetic oxygen atoms. The generation technique involves laser-induced breakdown of molecular oxygen followed by a rapid expansion of energetic oxygen atoms. The high-velocity streams developed in an evacuated hypersonic nozzle have average O-atom velocities of about 5 to 13 km/s, with an estimated total production of 10 to the 18th atoms per pulse over pulse durations of several microseconds. Results on preliminary material degradation tests conducted with this test facility have been reported by Caledonia et al. (1987). Diagrams of the experimental setup are included.

  13. Nanostructured materials and their applications

    CERN Document Server

    Logothetidis, Stergios

    2012-01-01

    This book applies nanostructures and nanomaterials to energy and organic electronics, offering advanced deposition and processing methods and theoretical and experimental aspects for nanoparticles, nanotubes and thin films for organic electronics applications.

  14. Nanoprobes, nanostructured materials and solid state materials

    Science.gov (United States)

    Yin, Houping

    2005-07-01

    Novel templates have been developed to prepare nanostructured porous materials through nonsurfactant templated pathway. And new applications of these materials, such as drug delivery and molecular imprinting, have been explored. The relationship between template content and pore structure has been investigated. The composition and pore structures were studied in detail using IR, TGA, SEM, TEM, BET and XRD. The obtained mesoporous materials have tunable diameters in the range of 2--12 nm. Due to the many advantages of this nonsurfactant templated pathway, such as environment friendly and biocompatibility, controlled release of antibiotics in the nanoporous materials were studied. The in vitro release properties were found to depend on the silica structures which were well tuned by varying the template content. A controlled long-term release pattern of vancomycin was achieved when the template content was 30 wt% or lower. Nanoscale electrochemical probes with dimensions as small as 50 nm in diameter and 1--2 mum in length were fabricated using electron beam deposition on the apex of conventional micron size electrodes. The electroactive region was limited to the extreme tip of the nanoprobe by coating with an insulating polymer and re-opening of the coating at the extreme tip. The novel nanoelectrodes thus prepared were employed to probe neurons in mouse brain slice and the results suggest that the nanoprobes were capable of recording neuronal excitatory postsynaptic potential signals. Interesting solid state chemistry was found in oxygenated iron phthalocyanine. Their Mossbauer spectra show the formation of four oxygenated species apart from the unoxygenated parent compound. The oxygen-bridged compounds formed in the solid matrix bear no resemblance to the one formed by solution chemistry. Tentative assignment of species has been made with the help of Mossbauer and IR spectroscopy. An effort to modify aniline trimer for potential nanoelectronics applications and to

  15. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    Science.gov (United States)

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-11-01

    This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  16. Hierarchically nanostructured materials for sustainable environmental applications

    Science.gov (United States)

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-01-01

    This review presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions, and multiple functionalities toward water remediation, biosensing, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing, and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology. PMID:24790946

  17. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    Directory of Open Access Journals (Sweden)

    Zheng eRen

    2013-11-01

    Full Text Available This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  18. Application opportunities for nanostructured materials and coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gell, M. [Connecticut Univ., Storrs, CT (United States). Dept. of Metallurgy

    1995-12-01

    Nanostructured materials have the potential to change materials science as we know it today significantly, as well as to provide a new generation of materials with a quantum improvement in properties. While many interesting properties have been generated in the laboratory, there is still much work to be done before there are production applications for nanostructured materials and coatings in gas turbine engines and similar demanding strength- and temperature-limited applications. This paper (1) describes the need for improved materials in gas turbine engines, (2) summarizes the improved physical and mechanical properties that have been reported for nanostructured materials, (3) discusses a research and development methodology that has the potential for accelerating technology implementation, and (4) describes high pay-off applications. (orig.)

  19. High Strain Rate Experiments of Energetic Material Binder

    OpenAIRE

    Rangel Mendoza, Roberto; Harr, Michael; Chen, Weinong

    2016-01-01

    Energetic materials, in particular HMX, is widely used in many applications as polymer bonded explosives (PBX) and rocket propellant. However, when damaged, HMX is known to be an unstable substance which renders it a hazardous material and in some cases unreliable. Finding critical mechanical conditions at high rates that render various forms of energetic materials as unreliable would be vital to understand the effects that vibrations and compression forces have on energetic materials. A bett...

  20. Shockwave Consolidation of Nanostructured Thermoelectric Materials

    Science.gov (United States)

    Prasad, Narasimha S.; Taylor, Patrick; Nemir, David

    2014-01-01

    Nanotechnology based thermoelectric materials are considered attractive for developing highly efficient thermoelectric devices. Nano-structured thermoelectric materials are predicted to offer higher ZT over bulk materials by reducing thermal conductivity and increasing electrical conductivity. Consolidation of nano-structured powders into dense materials without losing nanostructure is essential towards practical device development. Using the gas atomization process, amorphous nano-structured powders were produced. Shockwave consolidation is accomplished by surrounding the nanopowder-containing tube with explosives and then detonating. The resulting shock wave causes rapid fusing of the powders without the melt and subsequent grain growth. We have been successful in generating consolidated nano-structured bismuth telluride alloy powders by using the shockwave technique. Using these consolidated materials, several types of thermoelectric power generating devices have been developed. Shockwave consolidation is anticipated to generate large quantities of nanostructred materials expeditiously and cost effectively. In this paper, the technique of shockwave consolidation will be presented followed by Seebeck Coefficient and thermal conductivity measurements of consolidated materials. Preliminary results indicate a substantial increase in electrical conductivity due to shockwave consolidation technique.

  1. Nonlinear Electromagnetic Interactions in Energetic Materials

    CERN Document Server

    Wood, M A; Moore, D S

    2016-01-01

    We study the scattering of electromagnetic waves in anisotropic energetic materials. Nonlinear light-matter interactions in molecular crystals result in frequency-conversion and polarization changes. Applied electromagnetic fields of moderate intensity can induce these nonlinear effects without triggering chemical decomposition, offering a mechanism for non-ionizing identification of explosives. We use molecular dynamics simulations to compute such two-dimensional Raman spectra in the terahertz range for planar slabs made of PETN and ammonium nitrate. We discuss third-harmonic generation and polarization-conversion processes in such materials. These observed far-field spectral features of the reflected or transmitted light may serve as an alternative tool for stand-off explosive detection.

  2. Towards coherent control of energetic material initiation

    Energy Technology Data Exchange (ETDEWEB)

    Greenfield, Margo T [Los Alamos National Laboratory; Mcgrane, Shawn D [Los Alamos National Laboratory; Scharff, R Jason [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

    2009-01-01

    Direct optical initiation (DOI) of energetic materials using coherent control of localized energy deposition requires depositing energy into the material to produce a critical size hot spot, which allows propagation of the reaction and thereby initiation, The hot spot characteristics needed for growth to initiation can be studied using quantum controlled initiation (QCI). Achieving direct quantum controlled initiation (QCI) in condensed phase systems requires optimally shaped ultrafast laser pulses to coherently guide the energy flow along the desired paths. As a test of our quantum control capabilities we have successfully demonstrated our ability to control the reaction pathway of the chemical system stilbene. An acousto-optical modulator based pulse shaper was used at 266 nm, in a shaped pump/supercontinuum probe technique, to enhance and suppress th relative yields of the cis- to trans-stilbene isomerization. The quantum control techniques tested in the stilbene experiments are currently being used to investigate QCI of the explosive hexanitroazobenzene (HNAB).

  3. Characterization of thermally degraded energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Renlund, A.M.; Miller, J.C.; Trott, W.M.; Erickson, K.L.; Hobbs, M.L.; Schmitt, R.G.; Wellman, G.W.; Baer, M.R.

    1997-12-31

    Characterization of the damage state of a thermally degraded energetic material (EM) is a critical first step in understanding and predicting cookoff behavior. Unfortunately, the chemical and mechanical responses of heated EMs are closely coupled, especially if the EM is confined. The authors have examined several EMs in small-scale experiments (typically 200 mg) heated in both constant-volume and constant-load configurations. Fixtures were designed to minimize free volume and to contain gas pressures to several thousand psi. The authors measured mechanical forces or displacements that correlated to thermal expansion, phase transitions, material creep and gas pressurization as functions of temperature and soak time. In addition to these real-time measurements, samples were recovered for postmortem examination, usually with scanning electron microscopy (SEM) and chemical analysis. The authors present results on EMs (HMX and TATB), with binders (e.g., PBX 9501, PBX 9502, LX-14) and propellants (Al/AP/HTPB).

  4. Environmentally compatible next generation green energetic materials (GEMs).

    Science.gov (United States)

    Talawar, M B; Sivabalan, R; Mukundan, T; Muthurajan, H; Sikder, A K; Gandhe, B R; Rao, A Subhananda

    2009-01-30

    This paper briefly reviews the literature work reported on the environmentally compatible green energetic materials (GEMs) for defence and space applications. Currently, great emphasis is laid in the field of high-energy materials (HEMs) to increase the environmental stewardship along with the deliverance of improved performance. This emphasis is especially strong in the areas of energetic materials, weapon development, processing, and disposal operations. Therefore, efforts are on to develop energetic materials systems under the broad concept of green energetic materials (GEMs) in different schools all over the globe. The GEMs program initiated globally by different schools addresses these challenges and establishes the framework for advances in energetic materials processing and production that promote compliance with environmental regulations. This review also briefs the principles of green chemistry pertaining to HEMs, followed by the work carried out globally on environmentally compatible green energetic materials and allied ingredients.

  5. Multidimensional DDT modeling of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Baer, M.R.; Hertel, E.S.; Bell, R.L.

    1995-07-01

    To model the shock-induced behavior of porous or damaged energetic materials, a nonequilibrium mixture theory has been developed and incorporated into the shock physics code, CTH. The foundation for this multiphase model is based on a continuum mixture formulation given by Baer and Nunziato. This multiphase mixture model provides a thermodynamic and mathematically-consistent description of the self-accelerated combustion processes associated with deflagration-to-detonation and delayed detonation behavior which are key modeling issues in safety assessment of energetic systems. An operator-splitting method is used in the implementation of this model, whereby phase diffusion effects are incorporated using a high resolution transport method. Internal state variables, forming the basis for phase interaction quantities, are resolved during the Lagrangian step requiring the use of a stiff matrix-free solver. Benchmark calculations are presented which simulate low-velocity piston impact on a propellant porous bed and experimentally-measured wave features are well replicated with this model. This mixture model introduces micromechanical models for the initiation and growth of reactive multicomponent flow that are key features to describe shock initiation and self-accelerated deflagration-to-detonation combustion behavior. To complement one-dimensional simulation, two-dimensional numerical calculations are presented which indicate wave curvature effects due to the loss of wall confinement. This study is pertinent for safety analysis of weapon systems.

  6. Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria

    Science.gov (United States)

    2015-07-01

    L R E P O R T DTRA-TR-13-52 Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria Distribution Statement A...Z39.18 00-07-2015 Technical N/A Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria HDTRA1-10-1-0108 Emily M. Hunt, Ph.D. West...understand the interaction between spore forming bacteria and thermite reactions and products and to exploit energetic material reactions with

  7. Energetic materials destruction using molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Upadhye, R.S.; Watkins, B.E.; Pruneda, C.O.; Brummond, W.A.

    1994-04-29

    The Lawrence Livermore National Laboratory in conjunction with the Energetic Materials Center is developing methods for the safe and environmentally sound destruction of explosives and propellants as a part of the Laboratory`s ancillary demilitarization mission. LLNL has built a small-scale unit to test the destruction of HE using the Molten Salt Destruction (MSD) Process. In addition to the high explosive HMX, destruction has been carried out on RDX, PETN, ammonium picrate, TNT, nitroguanadine, and TATB. Also destroyed was a liquid gun propellant comprising hydroxyammonium nitrate, triethanolammonium nitrate and water. In addition to these pure components, destruction has been carried out on a number of commonly used formulations, such as LX-10, LX-16, LX-17, and PBX-9404.

  8. The importance of the energetic species in pulsed laser deposition for nanostructuring.

    Science.gov (United States)

    Castelo, A; Afonso, C N; Pesce, E; Piscopiello, E

    2012-03-16

    This work reports on the optical and structural properties of nanostructured films formed by Ag nano-objects embedded in amorphous aluminium oxide (a-Al(2)O(3)) prepared by alternate pulsed laser deposition (PLD). The aim is to understand the importance of the energetic species involved in the PLD process for nanostructuring, i.e. for organizing nanoparticles (NPs) in layers or for self-assembling them into nanocolumns (NCls), all oriented perpendicular to the substrate. In order to change the kinetic energy of the species arriving at the substrate, we use a background gas during the deposition of the embedding a-Al(2)O(3) host. It was produced either in vacuum or in a gas pressure (helium and argon) while the metal NPs were always produced in vacuum. The formation of NPs or NCls is easily identified through the features of the surface plasmon resonances (SPR) in the extinction spectra and confirmed by electron microscopy. The results show that both the layer organization and self-assembling of the metal are prevented when the host is produced in a gas pressure. This result is discussed in terms of the deceleration of species arriving at the substrate in gas that reduces the metal sputtering by host species (by ≈58%) as well as the density of the host material (by ≥19%). These reductions promote the formation of large voids along which the metal easily diffuses, thus preventing organization and self-organisation, as well as an enhancement of the amount of metal that is deposited.

  9. Strategies for Tuning the Reactivity of NanoEnergetic Materials

    Science.gov (United States)

    Prakash, Anand

    2005-07-01

    Nanostructured fuel/oxidizer composites are being looked upon as a possible approach to enhance energy release rates. Here we report on two approaches to moderate/tune reactivity. In the first example we accelerate reactivity. The method is based on electrostatically enhanced assembly to promote the preferential arrangement of aluminum (fuel) nanoparticles with iron oxide (oxidizer) nanoparticles in the aerosol phase. Two unipolar chargers are employed to generate oppositely charged aluminum and iron oxide particles, which enhance the formation of intimately interconnected nanocomposite energetic materials. The results of burning tests and thermal analysis using differential scanning calorimetry (DSC) showed that aluminum/iron oxide nanocomposite aerosol materials synthesized by bipolar assembly had burning rates that are a factor of 10 higher than those produced by random Brownian coagulation. In a second approach we employ a very reactive oxidizer (Potassium permanganate; ˜150 nm) and create a less reactive shell (Iron oxide). The measured reactivity for a nano-Al/composite oxidizer could be varied by more than a factor of 10 as measured by the pressurization rate in a closed vessel (Psi/microsecond), by changing the coating thickness of the iron oxide. The composite oxidizer nanoparticles were synthesized by a new aerosol approach, where the non-wetting interaction between iron oxide and molten potassium permanganate aids the phase segregation of a nanocomposite droplet into a core-shell structure.

  10. Energetic materials: crystallization, characterization and insensitive plastic bonded explosives

    NARCIS (Netherlands)

    Heijden, A.E.D.M. van der; Creyghton, Y.L.M.; Marino, E.; Bouma, R.H.B.; Scholtes, G.J.H.G.; Duvalois, W.; Roelands, C.P.M.

    2008-01-01

    The product quality of energetic materials is predominantly determined by the crystallization process applied to produce these materials. It has been demonstrated in the past that the higher the product quality of the solid energetic ingredients, the less sensitive a plastic bonded explosive contain

  11. Particle coating – a novel trend in energetic materials engineering

    NARCIS (Netherlands)

    Abadjieva, E.; Heijden, A.E.D.M. van der; Creyghton, Y.L.M.

    2010-01-01

    The development of new energetic materials with enhanced blast properties requires better understanding of factors as particle type, size and particle/matrix distribution. The ability of growing a coating on particles opens new possibilities in energetic materials engineering. Functionalities as

  12. Energetic materials: crystallization, characterization and insensitive plastic bonded explosives

    NARCIS (Netherlands)

    Heijden, A.E.D.M. van der; Creyghton, Y.L.M.; Marino, E.; Bouma, R.H.B.; Scholtes, G.J.H.G.; Duvalois, W.; Roelands, C.P.M.

    2008-01-01

    The product quality of energetic materials is predominantly determined by the crystallization process applied to produce these materials. It has been demonstrated in the past that the higher the product quality of the solid energetic ingredients, the less sensitive a plastic bonded explosive

  13. Shear initiated reactions in energetic and reactive materials

    NARCIS (Netherlands)

    Meuken, B.; Martinez Pacheco, M.; Verbeek, H.J.; Bouma, R.H.B.; Katgerman, L.

    2006-01-01

    Deformation of energetic materials may cause undesired reactions and therefore hazardous situations. The deformation of an energetic material and in particular shear deformation is studied in this paper. Understanding of the phenomena leading to shear initiation is not only necessary to explain for

  14. Shear initiated reactions in energetic and reactive materials

    NARCIS (Netherlands)

    Meuken, B.; Martinez Pacheco, M.; Verbeek, H.J.; Bouma, R.H.B.; Katgerman, L.

    2006-01-01

    Deformation of energetic materials may cause undesired reactions and therefore hazardous situations. The deformation of an energetic material and in particular shear deformation is studied in this paper. Understanding of the phenomena leading to shear initiation is not only necessary to explain for

  15. Nanostructured materials in the food industry.

    Science.gov (United States)

    Augustin, Mary Ann; Sanguansri, Peerasak

    2009-01-01

    Nanotechnology involves the application, production, and processing of materials at the nanometer scale. Biological- and physical-inspired approaches, using both conventional and innovative food processing technologies to manipulate matter at this scale, provide the food industry with materials with new functionalities. Understanding the assembly behavior of native and modified food components is essential in developing nanostructured materials. Functionalized nanostructured materials are finding applications in many sectors of the food industry, including novel nanosensors, new packaging materials with improved mechanical and barrier properties, and efficient and targeted nutrient delivery systems. An improved understanding of the benefits and the risks of the technology based on sound scientific data will help gain the acceptance of nanotechnology by the food industry. New horizons for nanotechnology in food science may be achieved by further research on nanoscale structures and methods to control interactions between single molecules.

  16. Photoemission from optoelectronic materials and their nanostructures

    CERN Document Server

    Ghatak, Kamakhya Prasad; Bhattacharya, Sitangshu

    2009-01-01

    This monograph investigates photoemission from optoelectronic materials and their nanostructures. It contains open-ended research problems which form an integral part of the text and are useful for graduate courses as well as aspiring Ph.D.'s and researchers..

  17. Understanding and tuning nanostructured materials for chemical energy conversion

    Science.gov (United States)

    Jian, Guoqiang

    The conversion of energy that employs chemical reaction is termed chemical energy conversion. In my dissertation, I have focused on chemical energy conversion systems involving energetic materials and lithium ion batteries, where performance is strongly dependent on the properties of materials and their architecture. The objective of this study is to enhance our understanding and tuning of nanostructured materials that might find application toward energetic materials and electrode materials in lithium ion batteries. Rapid heating diagnostics tools, i.e. temperature-jump techniques, have been used to study the ignition of aluminum nanoparticles, nanothermite reaction mechanism and metal oxides nanoparticles decomposition under rapid heating conditions (˜105-106 K/s). Time-resolved mass spectra results support the hypothesis that Al containing species diffuse outwards through the oxide shell. Low effective activation energies were found for metal oxides nanoparticles decomposition at high heating rates, implying the mass transfer control at high heating rates. The role of oxygen release from oxidizer in nanothermite reactions have been examined for several different systems, including some using microsized oxidizer (i.e., nano-Al/micro-I 2O5). In particular, for periodate based nanothermites, direct evidence from high heating rate SEM and mass spectrometry results support that direct gas phase oxygen release from oxidizer decomposition is critical in its ignition and combustion. Efforts have also been made to synthesize nanostructured materials for nanoenergetic materials and lithium ion batteries applications. Hollow CuO spheres were synthesized by aerosol spray pyrolysis, employing a gas blowing mechanism for the formation of hollow structure during aerosol synthesis. The materials synthesized as oxidizers in nanothermite demonstrated superior performance, and of particular note, periodate salts based nanothermite demonstrated the best gas generating performance

  18. Nanostructure studies of strongly correlated materials.

    Science.gov (United States)

    Wei, Jiang; Natelson, Douglas

    2011-09-01

    Strongly correlated materials exhibit an amazing variety of phenomena, including metal-insulator transitions, colossal magnetoresistance, and high temperature superconductivity, as strong electron-electron and electron-phonon couplings lead to competing correlated ground states. Recently, researchers have begun to apply nanostructure-based techniques to this class of materials, examining electronic transport properties on previously inaccessible length scales, and applying perturbations to drive systems out of equilibrium. We review progress in this area, particularly emphasizing work in transition metal oxides (Fe(3)O(4), VO(2)), manganites, and high temperature cuprate superconductors. We conclude that such nanostructure-based studies have strong potential to reveal new information about the rich physics at work in these materials.

  19. Gas sensors based on nanostructured materials.

    Science.gov (United States)

    Jiménez-Cadena, Giselle; Riu, Jordi; Rius, F Xavier

    2007-11-01

    Gas detection is important for controlling industrial and vehicle emissions, household security and environmental monitoring. In recent decades many devices have been developed for detecting CO(2), CO, SO(2), O(2), O(3), H(2), Ar, N(2), NH(3), H(2)O and several organic vapours. However, the low selectivity or the high operation temperatures required when most gas sensors are used have prompted the study of new materials and the new properties that come about from using traditional materials in a nanostructured mode. In this paper, we have reviewed the main research studies that have been made of gas sensors that use nanomaterials. The main quality characteristics of these new sensing devices have enabled us to make a critical review of the possible advantages and drawbacks of these nanostructured material-based sensors.

  20. Enforced Layer-by-Layer Stacking of Energetic Salts towards High-Performance Insensitive Energetic Materials.

    Science.gov (United States)

    Zhang, Jiaheng; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

    2015-08-26

    Development of modern high-performance insensitive energetic materials is significant because of the increasing demands for both military and civilian applications. Here we propose a rapid and facile strategy called the "layer hydrogen bonding pairing approach" to organize energetic molecules via layer-by-layer stacking, which grants access to tunable energetic materials with targeted properties. Using this strategy, an unusual energetic salt, hydroxylammonium 4-amino-furazan-3-yl-tetrazol-1-olate, with good detonation performances and excellent sensitivities, was designed, synthesized, and fully characterized. In addition, the expected unique layer-by-layer structure with a high crystal packing coefficient was confirmed by single-crystal X-ray crystallography. Calculations indicate that the layer-stacking structure of this material can absorb the mechanical stimuli-induced kinetic energy by converting it to layer sliding, which results in low sensitivity.

  1. Chemical Conversion of Energetic Materials to Higher Value Products

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A R; Hsu, P C; Coburn, M D; Schmidt, R D; Pagoria, P F; Lee, G S

    2005-04-19

    The objective of this program is to develop new processes for the disposal of surplus energetic materials. Disposal through open burning/open detonation (OB/OD) is considered less attractive today due to environmental, cost and safety concerns. The use of energetic materials as chemical feedstocks for higher value products can provide environmentally sound and cost-effective alternatives to OB/OD. Our recent studies on the conversion of surplus energetic materials (Explosive D, TNT) to higher value products will be described.

  2. Hydrogen storage in nanostructured materials

    Energy Technology Data Exchange (ETDEWEB)

    Assfour, Bassem

    2011-02-28

    Hydrogen is an appealing energy carrier for clean energy use. However, storage of hydrogen is still the main bottleneck for the realization of an energy economy based on hydrogen. Many materials with outstanding properties have been synthesized with the aim to store enough amount of hydrogen under ambient conditions. Such efforts need guidance from material science, which includes predictive theoretical tools. Carbon nanotubes were considered as promising candidates for hydrogen storage applications, but later on it was found to be unable to store enough amounts of hydrogen under ambient conditions. New arrangements of carbon nanotubes were constructed and hydrogen sorption properties were investigated using state-of-the-art simulation methods. The simulations indicate outstanding total hydrogen uptake (up to 19.0 wt.% at 77 K and 5.52wt.% at 300 K), which makes these materials excellent candidates for storage applications. This reopens the carbon route to superior materials for a hydrogen-based economy. Zeolite imidazolate frameworks are subclass of MOFs with an exceptional chemical and thermal stability. The hydrogen adsorption in ZIFs was investigated as a function of network geometry and organic linker exchange. Ab initio calculations performed at the MP2 level to obtain correct interaction energies between hydrogen molecules and the ZIF framework. Subsequently, GCMC simulations are carried out to obtain the hydrogen uptake of ZIFs at different thermodynamic conditions. The best of these materials (ZIF-8) is found to be able to store up to 5 wt.% at 77 K and high pressure. We expected possible improvement of hydrogen capacity of ZIFs by substituting the metal atom (Zn{sup 2+}) in the structure by lighter elements such as B or Li. Therefore, we investigated the energy landscape of LiB(IM)4 polymorphs in detail and analyzed their hydrogen storage capacities. The structure with the fau topology was shown to be one of the best materials for hydrogen storage. Its

  3. Investigations of Novel Energetic Materials to Stabilize Rocket Motors

    Science.gov (United States)

    2002-04-30

    and various additives were developed in the second half of the 20th Century. The earliest such propellants were asphalt -based developed at GALCIT with...Decomposition of Energetic Materials 74. Volatile Metal Isocyanates from Flash Pyrolysis of Metal-NTO and Metal-Picrate Salts and an Application Hypothesis...B. Brill, T. L. Zhang and B. C. Tappan, Thermal Decomposition of Energetic Materials 74. Volatile Metal Isocyanates from Flash Pyrolysis of Metal-NTO

  4. Leafy nanostructure PANI for material of supercapacitors

    Directory of Open Access Journals (Sweden)

    XI Dong

    2013-06-01

    Full Text Available Nanostructure conducting polyaniline(PANI has great potential applications in supercapacitor electrode materials.In this paper,we report a template-free approach to synthesize PANI by a galvanostatic current procedure with a three-electrode configuration directly on indium-doped tin-oxide substrates (ITO.The morphology of product was characterized by Hitachi S-4800 field emission scanning electron microscope (FE-SEM.Due to the nanostructure,the specific capacitance of PANI film with the thickness of 100nm were measured as high as 829 F/g and 667 F/g at a charge-discharge current density of 1 A/g and 10 A/g respectively.After 500 cycle charge-discharge test employed at the current density of 20 A/g the PANI film still had a 95.1% capacitance retention.

  5. Electrochemical Synthesis and Characterization of Nanostructured Chalcogenide Materials

    OpenAIRE

    Chang, Chong Hyun

    2011-01-01

    Nanostructured materials have attracted extensive attention due to their small dimension and enhanced properties compared to bulk materials, and their large range of potential applications in energy harvesting devices. Among these materials, nanostructured chalcogenides play an important role in thermoelectric and solar cell devices. Electrochemical techniques have drawn attention as an improved method for synthesizing nanostructured chalcogenide materials, since they provide a cost-effective...

  6. Energetic Materials Effects on Essential Soil Processes: Decomposition of Orchard Grass (Dactylis glomerata) Litter in Soil Contaminated with Energetic Materials

    Science.gov (United States)

    2014-02-01

    GRASS (DACTYLIS GLOMERATA) LITTER IN SOIL CONTAMINATED WITH ENERGETIC MATERIALS ECBC-TR-1199 Roman G. Kuperman Ronald T. Checkai Michael Simini...of Orchard Grass (Dactylis glomerata) Litter in Soil Contaminated with Energetic Materials 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...soils using the U.S. Environmental Protection Agency Method 8330A. The results showed that soil contamination with 2,4-DNT or NG can inhibit litter

  7. Environmentally Responsible Energetic Materials: Another Look at the Styphnates

    Science.gov (United States)

    Collins, Adam; Angliss, Timothy; Proud, William

    2009-06-01

    Lead Styphnate (lead 2,4,6-trinitroresorcinate) has many applications as a primary explosive, most notably in priming compositions. Its largest drawback, however, is the toxicity of lead. Heavy metals often feature in primary explosives, providing favourable density, bonding, and reaction products; but, the toxic nature of heavy metals makes these explosives of limited use. Current research efforts are being made to design new energetic materials (such as those based around the 5-nitrotetrazole molecule), but familiar energetics can still be of use. The styphnate anion provides many favourable energetic qualities (such as a ring structure and nitro groups), and while the lead salt has proven its usefulness, other metallic styphnates also provide a range of energetic qualities. This paper reports on ignition thresholds, energetic output, and thermal properties of the following salts of trinitroresorcinol: Barium, Bismuth, Calcium, Copper, Lithium, and Lead. Such information provides a list of characterized energetic materials, but also insight into how metal cations can control measurable energetic effects at the molecular and crystal level.

  8. Mechanical Spectroscopy of Nanostructured Composite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Mari, Daniele; Schaller, Robert; Mazaheri, Mehdi, E-mail: daniele.mari@epfl.ch [Ecole Polytechnique Federale de Lausanne, Laboratoire de Physique de la Matiere Complexe, Groupe de Spectroscopie Mecanique, CH-1015 Lausanne (Switzerland)

    2011-07-06

    The thermo-mechanical behavior of different nano-structured composite materials, which were processed within the SAPHIR European Integrated Project, has been characterized by mechanical spectroscopy. The obtained results show clearly that creep resistance of fine grain ceramics such as zirconia can be improved by carbon nano-tube (CNT) reinforcements. On the other hand the elastic modulus and the damping capacity of aluminum matrix composites were increased by SiC nano-particle additions. It has also been observed that CNT additions are responsible for a better thermal stability of polymer such as ABS (Acrylonitrile-Butadiene-Styrene) used in automotive industry.

  9. Computational design of surfaces, nanostructures and optoelectronic materials

    Science.gov (United States)

    Choudhary, Kamal

    Properties of engineering materials are generally influenced by defects such as point defects (vacancies, interstitials, substitutional defects), line defects (dislocations), planar defects (grain boundaries, free surfaces/nanostructures, interfaces, stacking faults) and volume defects (voids). Classical physics based molecular dynamics and quantum physics based density functional theory can be useful in designing materials with controlled defect properties. In this thesis, empirical potential based molecular dynamics was used to study the surface modification of polymers due to energetic polyatomic ion, thermodynamics and mechanics of metal-ceramic interfaces and nanostructures, while density functional theory was used to screen substituents in optoelectronic materials. Firstly, polyatomic ion-beams were deposited on polymer surfaces and the resulting chemical modifications of the surface were examined. In particular, S, SC and SH were deposited on amorphous polystyrene (PS), and C2H, CH3, and C3H5 were deposited on amorphous poly (methyl methacrylate) (PMMA) using molecular dynamics simulations with classical reactive empirical many-body (REBO) potentials. The objective of this work was to elucidate the mechanisms by which the polymer surface modification took place. The results of the work could be used in tailoring the incident energy and/or constituents of ion beam for obtaining a particular chemistry inside the polymer surface. Secondly, a new Al-O-N empirical potential was developed within the charge optimized many body (COMB) formalism. This potential was then used to examine the thermodynamic stability of interfaces and mechanical properties of nanostructures composed of aluminum, its oxide and its nitride. The potentials were tested for these materials based on surface energies, defect energies, bulk phase stability, the mechanical properties of the most stable bulk phase, its phonon properties as well as with a genetic algorithm based evolution theory of

  10. Electrical Breakdown Characteristic of Nanostructured W-Cu Contacts Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Junbo; CHEN Wen'ge; DING Bingjun

    2006-01-01

    Nanostructured (NS) W- Cu composite powder was prepared by mechanical alloying ( MA ), and nanostructured bulk of W- Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The microstructure, electric conductivity, hardness and break down voltage of NS W-Cu alloys were measured and compared to those of conventional W- Cu alloys prepared by powder metallurgy. The experimental results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of nanostructured W- Cu contacts materials. Also, the nanostructured W- Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.

  11. Final Technical Progress Report NANOSTRUCTURED MAGNETIC MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Charles M. Falco

    2012-09-13

    This report describes progress made during the final phase of our DOE-funded program on Nanostructured Magnetic Materials. This period was quite productive, resulting in the submission of three papers and presentation of three talks at international conferences and three seminars at research institutions. Our DOE-funded research efforts were directed toward studies of magnetism at surfaces and interfaces in high-quality, well-characterized materials prepared by Molecular Beam Epitaxy (MBE) and sputtering. We have an exceptionally well-equipped laboratory for these studies, with: Thin film preparation equipment; Characterization equipment; Equipment to study magnetic properties of surfaces and ultra-thin magnetic films and interfaces in multi-layers and superlattices.

  12. Silk fibroin nanostructured materials for biomedical applications

    Science.gov (United States)

    Mitropoulos, Alexander N.

    Nanostructured biopolymers have proven to be promising to develop novel biomedical applications where forming structures at the nanoscale normally occurs by self-assembly. However, synthesizing these structures can also occur by inducing materials to transition into other forms by adding chemical cross-linkers, changing pH, or changing ionic composition. Understanding the generation of nanostructures in fluid environments, such as liquid organic solvents or supercritical fluids, has not been thoroughly examined, particularly those that are based on protein-based block-copolymers. Here, we examine the transformation of reconstituted silk fibroin, which has emerged as a promising biopolymer due to its biocompatibility, biodegradability, and ease of functionalization, into submicron spheres and gel networks which offer applications in tissue engineering and advanced sensors. Two types of gel networks, hydrogels and aerogels, have small pores and large surface areas that are defined by their structure. We design and analyze silk nanoparticle formation using a microfluidic device while offering an application for drug delivery. Additionally, we provide a model and characterize hydrogel formation from micelles to nanoparticles, while investigating cellular response to the hydrogel in an in vitro cell culture model. Lastly, we provide a second model of nanofiber formation during near-critical and supercritical drying and characterize the silk fibroin properties at different drying pressures which, when acting as a stabilizing matrix, shows to improve the activity of entrapped enzymes dried at different pressures. This work has created new nanostructured silk fibroin forms to benefit biomedical applications that could be applied to other fibrous proteins.

  13. Gold nanostructure materials in diabetes management

    Science.gov (United States)

    Si, Satyabrata; Pal, Arttatrana; Mohanta, Jagdeep; Sagar Satapathy, Smith

    2017-04-01

    Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia, and is now one of the most non-communicable diseases globally and can be lethal if not properly controlled. Prolonged exposure to chronic hyperglycemia, without proper management, can lead to various vascular complications and represents the main cause of morbidity and mortality in diabetes patients. Studies have indicated that major long-term complications of diabetes arise from persistent oxidative-nitrosative stress and dysregulation in multiple metabolic pathways. Presently, the main focus for diabetes management is to optimize the available techniques to ensure adequate blood sugar level, blood pressure and lipid profile, thereby minimizing the diabetes complications. In this regard, nanomedicine utilizing gold nanostructures has great potential and seems to be a promising option. The present review highlights the basic concepts and up-to-date literature survey of gold nanostructure materials in management of diabetes in several ways, which include sensing, imaging, drug delivery and therapy. The work can be of interest to various researchers working on basic and applied sciences including nanosciences.

  14. Nanostructured photovoltaic materials using block polymer assemblies

    Science.gov (United States)

    Mastroianni, Sarah Elizabeth

    Despite its potential as an abundant, sustainable alternative to non-renewable energy sources, solar energy currently is underutilized. Photovoltaics, which convert energy from sunlight into electricity, commonly are made from inorganic semiconductor materials that require expensive manufacturing and processing techniques. Alternatively, organic materials can be used to produce flexible and lightweight organic photovoltaic (OPV) devices, which can be prepared using solution-based processing techniques. However, OPV devices are limited by low efficiencies and short lifetimes compared to their inorganic counterparts. In OPV systems, charge carriers are generated in the active layer via the separation of excitons (electron-hole pairs) at interfaces between donor and acceptor materials. Because excitons have a limited diffusion length (˜10 nm), they may recombine before reaching a donor-acceptor interface if domain sizes are large. This exciton recombination can limit device efficiency; thus, the design parameters for improved active layer morphologies include large interfacial areas, small size scales, and continuous conducting pathways. Currently, most OPV devices are prepared by blending donor and acceptor materials in bulk heterojunction (BHJ) devices, often resulting in non-ideal, process-dependent morphologies. Alternatively, the self-assembly of block polymers (BP)s offers a reproducible means to generate nanostructured active layers. The work presented in this dissertation examines the synthetic approaches to preparing BPs containing different electroactive materials: non-conjugated, amorphous poly(vinyl-m-triphenylamine) [PVmTPA] and conjugated poly(3-alkythiophene) [P3AT] p-type materials as well as fullerene-based n-type materials. The synthesis and self-assembly of a model poly(methyl methacrylate)- b-PVmTPA system is presented. This work was extended to synthesize PVmTPA BPs with complementary poly(methyl methacrylate- co-hydroxyethyl methacrylate) [P

  15. Nanostructured Materials for Li-Ion Batteries and Beyond

    Directory of Open Access Journals (Sweden)

    Xifei Li

    2016-04-01

    Full Text Available This Special Issue “Nanostructured Materials for Li-Ion Batteries and Beyond” of Nanomaterials is focused on advancements in the synthesis, optimization, and characterization of nanostructured materials, with an emphasis on the application of nanomaterials for building high performance Li-ion batteries (LIBs and future systems.[...

  16. Chemical rocket propulsion a comprehensive survey of energetic materials

    CERN Document Server

    Shimada, Toru; Sinditskii, Valery; Calabro, Max

    2017-01-01

    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...

  17. Cesium pentazolate: A new nitrogen-rich energetic material

    Science.gov (United States)

    Steele, Brad A.; Stavrous, Elissaios; Prakapenka, Vitali B.; Radousky, Harry; Zaug, Joseph; Crowhurst, Jonathan C.; Oleynik, Ivan I.

    2017-01-01

    We report theoretical and experimental evidence for a new class of high-nitrogen content energetic material compounds consisting of molecular pentazoles, which are stabilized in the crystal phase upon introduction of elemental cesium. First-principles structural predictions show that the material with composition CsN5 is thermodynamically stable above 15 GPa. Indexing of the measured X-ray diffraction spectra indicate the synthesis of this material at 60 GPa as well its stability upon decompression down to 24 GPa.

  18. Thermal Damage Characterization of Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, P C; DeHaven, M R; Springer, H K; Maienschein, J L

    2009-08-14

    We conducted thermal damage experiments at 180?C on PBXN-9 and characterized its material properties. Volume expansion at high temperatures was very significant which led to a reduction in material density. 2.6% of weight loss was observed, which was higher than other HMX-based formulations. Porosity of PBXN-9 increased to 16% after thermal exposure. Small-scale safety tests (impact, friction, and spark) showed no significant sensitization when the damaged samples were tested at room temperature. Gas permeation measurements showed that gas permeability in damaged materials was several orders of magnitude higher than that in pristine materials. In-situ measurements of gas permeability and density were proved to be possible at higher temperatures.

  19. Modeling plasticity of materials with nanostructure

    Science.gov (United States)

    Kudinova, N. R.

    2017-02-01

    A new approach to modeling of the plasticity of materials with the particle size in the range from 3 to 20 nm (nanostructure) has been proposed. It is based on classical thermodynamic approach employing the surface tension of nanoparticles. Its main advantage is the minimum number of physical parameters in use. In the context of the proposed model, we calculated the dependence of the melting temperature on the nanoparticle size which is consistent with experimental data. The volume density of the surface energy of nanoparticles was also determined. This energy is assumed to be a significant part of the internal energy during deformation Yield point was interpreted as the result of changes of grains surface energy during the deformation. The obtained yield point dependence on the grain size was related to the Hall–Petch law, and this resulted in confirmation of the hypothesis on the crucial role of surface tension forces in the initial stage of plastic deformation of nanomaterials.

  20. Nanostructured Electrode Materials for Electrochemical Capacitor Applications

    Directory of Open Access Journals (Sweden)

    Hojin Choi

    2015-06-01

    Full Text Available The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013. Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

  1. Computational Materials: Modeling and Simulation of Nanostructured Materials and Systems

    Science.gov (United States)

    Gates, Thomas S.; Hinkley, Jeffrey A.

    2003-01-01

    The paper provides details on the structure and implementation of the Computational Materials program at the NASA Langley Research Center. Examples are given that illustrate the suggested approaches to predicting the behavior and influencing the design of nanostructured materials such as high-performance polymers, composites, and nanotube-reinforced polymers. Primary simulation and measurement methods applicable to multi-scale modeling are outlined. Key challenges including verification and validation of models are highlighted and discussed within the context of NASA's broad mission objectives.

  2. Debye screening length effects of nanostructured materials

    CERN Document Server

    Ghatak, Kamakhya Prasad

    2014-01-01

    This monograph solely investigates the Debye Screening Length (DSL) in semiconductors and their nano-structures. The materials considered are quantized structures of non-linear optical, III-V, II-VI, Ge, Te, Platinum Antimonide, stressed materials, Bismuth, GaP, Gallium Antimonide, II-V and Bismuth Telluride respectively. The DSL in opto-electronic materials and their quantum confined counterparts is studied in the presence of strong light waves and intense electric fields on the basis of newly formulated electron dispersion laws that control the studies of such quantum effect devices. The suggestions for the experimental determination of 2D and 3D DSL and the importance of measurement of band gap in optoelectronic materials under intense built-in electric field in nano devices and strong external photo excitation (for measuring photon induced physical properties) have also been discussed in this context. The influence of crossed electric and quantizing magnetic fields on the DSL and the DSL in heavily doped ...

  3. New fluidized bed reactor for coating of energetic materials

    NARCIS (Netherlands)

    Abadjieva, E.; Huijser, T.; Creyghton, Y.L.M.; Heijden, A.E.D.M. van der

    2009-01-01

    The process of altering and changing the properties of the energetic materials by coating has been studied extensively by several scientific groups. According to the desired application different coating techniques have been developed and applied to achieve satisfactory results. Among the already de

  4. New fluidized bed reactor for coating of energetic materials

    NARCIS (Netherlands)

    Abadjieva, E.; Huijser, T.; Creyghton, Y.L.M.; Heijden, A.E.D.M. van der

    2009-01-01

    The process of altering and changing the properties of the energetic materials by coating has been studied extensively by several scientific groups. According to the desired application different coating techniques have been developed and applied to achieve satisfactory results. Among the already

  5. Propulsion and energetic materials research in the Netherlands

    NARCIS (Netherlands)

    Zevenbergen, J.F.; Pekalski, A.A.; Heijden, A.E.D.M. van der; Keizers, H.L.J.; Berg, R.P. van den; Maree, A.G.M.; Vliet, L.D. van; Welland, W.H.M.; Wierckx, F.J.M.

    2005-01-01

    Fundamental research on new and existing propellant formulations and energetic materials in the Netherlands is essentially carried out by the Delft University of Technology, Utrecht University, the Dutch Defense Laboratory ‘TNO Defense Security and Safety’ and the SME Aerospace Propulsion Products.

  6. Inorganic nanostructured materials for high performance electrochemical supercapacitors.

    Science.gov (United States)

    Liu, Sheng; Sun, Shouheng; You, Xiao-Zeng

    2014-02-21

    Electrochemical supercapacitors (ES) are a well-known energy storage system that has high power density, long life-cycle and fast charge-discharge kinetics. Nanostructured materials are a new generation of electrode materials with large surface area and short transport/diffusion path for ions and electrons to achieve high specific capacitance in ES. This mini review highlights recent developments of inorganic nanostructure materials, including carbon nanomaterials, metal oxide nanoparticles, and metal oxide nanowires/nanotubes, for high performance ES applications.

  7. The Reactivity of Energetic Materials At Extreme Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fried, L E

    2006-10-23

    Energetic materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. Energetic materials are commonly divided into high explosives, propellants, and pyrotechnics. We will focus on high explosive (HE) materials here, although there is a great deal of commonality between the classes of energetic materials. Although the history of HE materials is long, their condensed-phase properties are poorly understood. Understanding the condensed-phase properties of HE materials is important for determining stability and performance. Information regarding HE material properties (for example, the physical, chemical, and mechanical behaviors of the constituents in plastic-bonded explosive, or PBX, formulations) is necessary for efficiently building the next generation of explosives as the quest for more powerful energetic materials (in terms of energy per volume) moves forward. In modeling HE materials there is a need to better understand the physical, chemical, and mechanical behaviors from fundamental theoretical principles. Among the quantities of interest in plastic-bonded explosives (PBXs), for example, are thermodynamic stabilities, reaction kinetics, equilibrium transport coefficients, mechanical moduli, and interfacial properties between HE materials and the polymeric binders. These properties are needed (as functions of stress state and temperature) for the development of improved micro-mechanical models, which represent the composite at the level of grains and binder. Improved micro-mechanical models are needed to describe the responses of PBXs to dynamic stress or thermal loading, thus yielding information for use in developing continuum models. Detailed descriptions of the chemical reaction mechanisms of condensed energetic materials at high densities and temperatures are essential for understanding events that occur at the reactive front under combustion or detonation conditions. Under

  8. Size-dependent density of nanoparticles and nanostructured materials

    Energy Technology Data Exchange (ETDEWEB)

    Nanda, Karuna Kar, E-mail: nanda@mrc.iisc.ernet.in [Materials Research Centre, Indian Institute of Science, Bangalore 12 (India)

    2012-10-01

    We discuss the size-dependent density of nanoparticles and nanostructured materials keeping the recent experimental results in mind. The density is predicted to increase with decreasing size for nanoparticles but it can decrease with size for nanostructured materials that corroborates the experimental results reported in the literature. -- Highlights: ► Density of nanoparticles depends mainly on the size-dependent lattice parameter. ► Density is predicted to increase with decreasing size for nanoparticles. ► Density decreases with size for nanostructured materials.

  9. Modeling thermal/chemical/mechanical response of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Baer, M.R.; Hobbs, M.L.; Gross, R.J. [and others

    1995-07-01

    An overview of modeling at Sandia National Laboratories is presented which describes coupled thermal, chemical and mechanical response of energetic materials. This modeling addresses cookoff scenarios for safety assessment studies in systems containing energetic materials. Foundation work is discussed which establishes a method for incorporating chemistry and mechanics into multidimensional analysis. Finite element analysis offers the capabilities to simultaneously resolve reactive heat transfer and structural mechanics in complex geometries. Nonlinear conduction heat transfer, with multiple step finite-rate chemistry, is resolved using a thermal finite element code. Rate equations are solved element-by-element using a modified matrix-free stiff solver This finite element software was developed for the simulation of systems requiring large numbers of finite elements. An iterative implicit scheme, based on the conjugate gradient method, is used and a hemi-cube algorithm is employed for the determination of view factors in surface-to-surface radiation transfer The critical link between the reactive heat transfer and mechanics is the introduction of an appropriate constitutive material model providing a stress-strain relationship for quasi-static mechanics analysis. This model is formally derived from bubble nucleation theory, and parameter variations of critical model parameters indicate that a small degree of decomposition leads to significant mechanical response. Coupled thermal/chemical/mechanical analysis is presented which simulates experiments designed to probe cookoff thermal-mechanical response of energetic materials.

  10. Modeling the Reactions of Energetic Materials in the Condensed Phase

    Energy Technology Data Exchange (ETDEWEB)

    Fried, L E; Manaa, M R; Lewis, J P

    2003-12-03

    High explosive (HE) materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. Although the history of HE materials is long, condensed-phase properties are poorly understood. Understanding the condensed-phase properties of HE materials is important for determining stability and performance. Information regarding HE material properties (for example, the physical, chemical, and mechanical behaviors of the constituents in plastic-bonded explosive, or PBX, formulations) is necessary in efficiently building the next generation of explosives as the quest for more powerful energetic materials (in terms of energy per volume) moves forward. In addition, understanding the reaction mechanisms has important ramifications in disposing of such materials safely and cheaply, as there exist vast stockpiles of HE materials with corresponding contamination of earth and groundwater at these sites, as well as a military testing sites The ability to model chemical reaction processes in condensed phase energetic materials is rapidly progressing. Chemical equilibrium modeling is a mature technique with some limitations. Progress in this area continues, but is hampered by a lack of knowledge of condensed phase reaction mechanisms and rates. Atomistic modeling is much more computationally intensive, and is currently limited to very short time scales. Nonetheless, this methodology promises to yield the first reliable insights into the condensed phase processes responsible for high explosive detonation. Further work is necessary to extend the timescales involved in atomistic simulations. Recent work in implementing thermostat methods appropriate to shocks may promise to overcome some of these difficulties. Most current work on energetic material reactivity assumes that electronically adiabatic processes dominate. The role of excited states is becoming clearer, however. These states are not accessible in perfect

  11. Sensitivity and performance of azole-based energetic materials.

    Science.gov (United States)

    Yu, Zijun; Bernstein, Elliot R

    2013-10-24

    Imidazole, pyrazole, 1,2,3-triazole-, 1,2,4-triazole-, and tetrazole-based energetic materials are theoretically investigated by employing density functional theory (DFT). Heats of formation (ΔfH(0)'s) for the studied compounds (298 K) in the gas phase are determined at the B3P86/6-311G (d, p) theory level through isodesmic reactions. The bond dissociation energies (BDEs) corresponding to NO2, NH2, CH3, and Cl removal from carbon or nitrogen positions of the azole ring are also calculated at the B3P86/6-311G (d, p) theory level. The substituent effect of electron-withdrawing (NO2, Cl) and electron-donating (NH2, CH3) groups on the ΔfH(0)s and BDEs is discussed. Both electron-withdrawing groups and electron-donating groups (except the CH3 group) dramatically increase the ΔfH(0)s of these energetic materials when the substituent is at an N position on the azole ring. For substitution at a C atom on the azole ring, electron-withdrawing and electron-donating groups have different effects on the ΔfH(0)s for different azole compounds. A correlation is developed for this series of energetics between impact sensitivity h50% and the defined sensitivity index (SI): based on this empirical relationship and its extrapolation, the impact sensitivities of compounds for which experiments are not available are provided. The promising energetic compounds in each groups, which have potentially good energetic performance and low sensitivity, are 1-amino-2,4,5-trinitroimidazole, 1-amino-3,4,5-trinitropyrazole, 1,4-dinitro-1,2,3-triazole, 1,3-dinitro-1,2,4-triazole, and 1-nitrotetrazole.

  12. Evaluation of nanoparticles in the performance of energetic materials

    Directory of Open Access Journals (Sweden)

    José Atílio Fritz Fidel Rocco

    2010-04-01

    Full Text Available The addition of nanosized metal particles in propulsion systems such as solid and liquid propellants, hybrid propellant and ramjet motors has recently became a major focus of research. Significant increases in the burning velocity and in the specific impulse are some of the advantages of using nano-scale energetic materials in many different types of propulsion systems. Aluminum has been largely employed as a metallic additive in energetic materials, also in a recently new propulsion system (aluminum/ice propulsion, “Alice”, and some studies show that the advantages of using nanosized aluminum instead of microsized aluminum are facilitating the ignition of the systems and allowing better incorporation of the components in the formulations and improving its homogeneity. Some of the combustion processes that require high pressures and even higher temperatures can occur in moderate conditions due to the increase of the surface area of the reactants, in this case, the metallic additive.

  13. Ultrafast laser diagnostics to investigate initiation fundamentals in energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Farrow, Darcie; Jilek, Brook Anton; Kohl, Ian Thomas; Kearney, Sean Patrick

    2013-08-01

    We present the results of a two year early career LDRD project, which has focused on the development of ultrafast diagnostics to measure temperature, pressure and chemical change during the shock initiation of energetic materials. We compare two single-shot versions of femtosecond rotational CARS to measure nitrogen temperature: chirped-probe-pulse and ps/fs hybrid CARS thermometry. The applicability of measurements to the combustion of energetic materials will be discussed. We have also demonstrated laser shock and particle velocity measurements in thin film explosives using stretched femtosecond laser pulses. We will discuss preliminary results from Al and PETN thin films. Agreement between our results and previous work will be discussed.

  14. UV fluorescence enhancement from nanostructured aluminum materials

    Science.gov (United States)

    Montanari, Danielle E.; Dean, Nathan; Poston, Pete E.; Blair, Steve; Harris, Joel M.

    2016-09-01

    Interest in label-free detection of biomolecules has given rise to the need for UV plasmonic materials. DNA bases and amino acid residues have electronic resonances in the UV which allow for sensitive detection of these species by surface-enhanced UV fluorescence spectroscopy. Electrochemical roughening has been used extensively to generate plasmonically-active metal surfaces that produce localized enhancement of excitation and emission of electromagnetic radiation from surface-bound molecules. Electrochemically roughened gold and silver surfaces produce enhancement in the visible and near-IR regions, but to the best of our knowledge, application of this technique for producing UV-enhancing substrates has not been reported. Using electropolishing of aluminum, we are able to generate nanostructured surfaces that produce enhanced spectroscopic detection of molecules in the UV. Aluminum is a natural choice for substrate composition as it exhibits a relatively large quality factor in the UV. We have fabricated electropolished aluminum films with nanometer scale roughness and have studied UV-excited fluorescence enhancement from submonolayer coverage of tryptophan on these substrates using a UV-laser based spectrometer. Quantitative dosing by dip-coating was used to deposit known surface concentrations of the aromatic amino acid tryptophan, so that fluorescence enhancement could be evaluated. Compared to a dielectric substrate (surface-oxidized silicon), we observe a 180-fold enhancement in the total fluorescence emitted by tryptophan on electropolished aluminum under photobleaching conditions, allowing detection of sub-monolayer coverages of molecules essential for development of biosensor technologies.

  15. Electronic State Decomposition of Energetic Materials and Model Systems

    Science.gov (United States)

    2010-11-17

    tetrazine1,4-dioxde ( DATO ), is investigated. Although these molecules are based on N -oxides of a tetrazine aromatic heterocyclic ring, their...nitramines, furazan, tetrazines, tetrazine-N oxides, terazoles, PETN, RDX,HMX,CL-20,DAATO,ACTO, DATO ,conical intersections Elliot R Bernstein Colorado State...Tetrazine-N-Oxide Based High Nitrogen Content Energetic Materials from Excited Electronic States," J. Chem. Phys. 131, 194304 (2009). A

  16. The influence of nanostructured materials on biointerfacial interactions.

    Science.gov (United States)

    Koegler, Peter; Clayton, Andrew; Thissen, Helmut; Santos, Gil Nonato C; Kingshott, Peter

    2012-12-01

    Control over biointerfacial interactions in vitro and in vivo is the key to many biomedical applications: from cell culture and diagnostic tools to drug delivery, biomaterials and regenerative medicine. The increasing use of nanostructured materials is placing a greater demand on improving our understanding of how these new materials influence biointerfacial interactions, including protein adsorption and subsequent cellular responses. A range of nanoscale material properties influence these interactions, and material toxicity. The ability to manipulate both material nanochemistry and nanotopography remains challenging in its own right, however, a more in-depth knowledge of the subsequent biological responses to these new materials must occur simultaneously if they are ever to be affective in the clinic. We highlight some of the key technologies used for fabrication of nanostructured materials, examine how nanostructured materials influence the behavior of proteins and cells at surfaces and provide details of important analytical techniques used in this context.

  17. Application of Nanostructures in Electrochromic Materials and Devices: Recent Progress.

    Science.gov (United States)

    Wang, Jin Min; Sun, Xiao Wei; Jiao, Zhihui

    2010-11-26

    The recent progress in application of nanostructures in electrochromic materials and devices is reviewed. ZnO nanowire array modified by viologen and WO₃, crystalline WO₃ nanoparticles and nanorods, mesoporous WO₃ and TiO₂, poly(3,4-ethylenedioxythiophene) nanotubes, Prussian blue nanoinks and nanostructures in switchable mirrors are reviewed. The electrochromic properties were significantly enhanced by applying nanostructures, resulting in faster switching responses, higher stability and higher optical contrast. A perspective on the development trends in electrochromic materials and devices is also proposed.

  18. Application of Nanostructures in Electrochromic Materials and Devices: Recent Progress

    Directory of Open Access Journals (Sweden)

    Jin Min Wang

    2010-11-01

    Full Text Available The recent progress in application of nanostructures in electrochromic materials and devices is reviewed. ZnO nanowire array modified by viologen and WO3, crystalline WO3 nanoparticles and nanorods, mesoporous WO3 and TiO2, poly(3,4-ethylenedioxythiophene nanotubes, Prussian blue nanoinks and nanostructures in switchable mirrors are reviewed. The electrochromic properties were significantly enhanced by applying nanostructures, resulting in faster switching responses, higher stability and higher optical contrast. A perspective on the development trends in electrochromic materials and devices is also proposed.

  19. Diagnostics for the Analysis of Surface Chemistry Effects on Composite Energetic Material Reactions

    Science.gov (United States)

    2015-10-30

    Distribution Unlimited Final Report: Diagnostics for the Analysis of Surface Chemistry Effects on Composite Energetic Material Reactions The views...peer-reviewed journals: Final Report: Diagnostics for the Analysis of Surface Chemistry Effects on Composite Energetic Material Reactions Report...2.00 4.00 Evan Vargas, Michelle L. Pantoya, Mohammed A Saed, Brandon L Weeks. Advanced Susceptors for Microwave Heating of Energetic Materials

  20. 77 FR 25932 - Revisions to the Export Administration Regulations (EAR): Control of Energetic Materials and...

    Science.gov (United States)

    2012-05-02

    ... Regulations (EAR): Control of Energetic Materials and Related Articles That the President Determines No Longer... this proposed rule describing how energetic materials and related articles that the President determines no longer warrant control under Category V (Explosives and Energetic Materials, Propellants...

  1. Surface analysis of nanostructured carbonaceous materials

    Science.gov (United States)

    Wepasnick, Kevin Andrew

    The characterization of surfaces is central to understanding its interaction with other materials. Current ground-breaking research in interfacial science is focusing on surfaces which have a nanoscopic-size to their structuring. In particular, carbon nanotubes (CNTs) have been explored extensively. However, to utilize these materials in commercial and scientific applications, the surfaces are often modified to tailor specific properties, such as dispersion, sorption, and reactivity. The focus of this thesis is to apply surface analytical techniques to explore the chemical and structural characteristics of modified nanostructured surfaces. Specifically studied are the covalent surface modifications of CNTs by strategies that involve the direct incorporation of specific elements into the graphene sidewalls by commonly used wet chemical oxidants. These resulting CNTs are then evaluated in terms of their change in surface chemistry and structure. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface oxidation, while chemical derivatization techniques in conjunction with XPS afforded the concentration of carboxyl, carbonyl, and hydroxyl groups on the CNT surface. Transmission electron microscopy (TEM) was able to provide detailed structural information on the modified CNT, including the extent of sidewall damage. Results indicate that the distribution of oxygen-containing functional groups was insensitive to the reaction conditions, but was dependent upon the identity of the oxidant. These trends in functional group concentration were then applied to determining environmental properties, specifically divalent metal cation sorption. Consistently, the increases in COOH functional groups result in an increase in sorption capacity of divalent metal cations, such as Zn2+ and Cd2+. Furthermore, the interactions of size-selected metal and metal-oxide nanoclusters with graphite surfaces were studied by atomic force microscopy (AFM), scanning tunneling

  2. Hollow Nanostructured Anode Materials for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2010-01-01

    Full Text Available Abstract Hollow nanostructured anode materials lie at the heart of research relating to Li-ion batteries, which require high capacity, high rate capability, and high safety. The higher capacity and higher rate capability for hollow nanostructured anode materials than that for the bulk counterparts can be attributed to their higher surface area, shorter path length for Li+ transport, and more freedom for volume change, which can reduce the overpotential and allow better reaction kinetics at the electrode surface. In this article, we review recent research activities on hollow nanostructured anode materials for Li-ion batteries, including carbon materials, metals, metal oxides, and their hybrid materials. The major goal of this review is to highlight some recent progresses in using these hollow nanomaterials as anode materials to develop Li-ion batteries with high capacity, high rate capability, and excellent cycling stability.

  3. Giant magnetoresistive nanostructured materials by electrodeposition

    Science.gov (United States)

    Myung, No Sang

    NiFe/Cu and CoFe/Cu multilayers and NiFe compositional modulated alloys (CMA) electrodeposited by newly developed flow-through electrochemical reactor. Sub-micron (Ni)Cu and nano-size (CoFe)Cu granular alloys have been electrodeposited by magneto-electrodeposition method. These two methods eliminate the problems confronted by conventional methods and provide a new direction in fabrication of nanostructured materials by electrodeposition. Prior to fabrication of GMR materials, electrodeposition kinetics of individual metals (Co, NiFe, Cu) were studied. In Co electrodeposition and dissolution from sulfate bath, substrates have a great impact on the initial growth mode of film. On polycrystalline platinum metal, cobalt film grew in hemispherical shape (nodule) where it grew in right conical shape on amorphous glass carbon. In NiFe alloys electrodeposition, the effects of applied current density, solution composition, substrate and solution hydrodynamics on current efficiency, film composition, crystal structure, corrosion resistant, and magnetic properties of NiFe alloys from all-chloride and citrate-sulfate-chloride bath have been studied. Citrate ions enhance the anomalous codeposition phenomena in NiFe electrodeposition. In crystal structure studies on electrodeposited. NiFe, the narrow mixed phase solid region was noted around 50% Fe. In addition, the smallest grain size were also observed in that region. In corrosion studies, the maximum corrosion resistance was observed at 50% Fe in naturally aerated 0.5 M NaCl. In Ni/Cu and Co/Cu multilayers by single bath technique, the optimum deposition potential ranges of pure copper and nickel (cobalt) were determined to minimize copper codeposition during nickel (cobalt) deposition and to minimize cobalt dissolution during copper deposition. Well defined laminated NiFe/Cu and CoFe/Cu multilayers and NiFe compositional modulated alloys (CMA) were successfully electrodeposited by utilizing flow-through electrochemical

  4. Phthalocyanine-Carbon Nanostructure Materials Assembled through Supramolecular Interactions.

    Science.gov (United States)

    Bottari, Giovanni; Suanzes, Juan A; Trukhina, Olga; Torres, Tomas

    2011-04-21

    The use of self-assembly for the construction of materials based on phthalocyanines and carbon nanostructures-fullerenes, single-walled carbon nanotubes, and graphene-has demonstrated to be a versatile strategy for the preparation of novel, multifunctional systems. Photophysical studies carried out on these photo- and electroactive supramolecular ensembles have revealed the occurrence of an efficient photoinduced electron-transfer process, thus paving the way for the utilization of these materials as active components in optoelectronic devices. This Perspective highlights the recent progress in the preparation of such materials and the potential use of these systems for the construction of nanostructured materials with singular physicochemical properties.

  5. Dynamic behavior of particulate/porous energetic materials

    Science.gov (United States)

    Nesterenko, Vitali F.; Chiu, Po-Hsun; Braithwaite, C. H.; Collins, Adam; Williamson, David Martin; Olney, Karl L.; Benson, David; McKenzie, Francesca

    2012-03-01

    Dynamic behavior of particulate/porous energetic materials in a broad range of dynamic conditions (low velocity impact and explosively driven expansion of rings) is discussed. Samples of these materials were fabricated using Cold Isostatic Pressing and Hot Isostatic Pressing with and without vacuum encapsulation. The current interest in these materials is due to the combination of their high strength and output of energy under critical conditions of mechanical deformation. They may exhibit high compressive and tensile strength with the ability to undergo bulk distributed fracture resulting in small size reactive fragments. The mechanical properties of these materials and the fragment sizes produced by fracturing are highly sensitive to mesostructure. For example, the dynamic strength of Al-W composites with fine W particles is significantly larger than the strength of composites with coarse W particles at the same porosity. The morphology of W inclusions had a strong effect on the dynamic strength and fracture pattern. Experimental results are compared with numerical data.

  6. Advances in science and technology of modern energetic materials: an overview.

    Science.gov (United States)

    Badgujar, D M; Talawar, M B; Asthana, S N; Mahulikar, P P

    2008-03-01

    Energetic materials such as explosives, propellants and pyrotechnics are widely used for both civilian and military explosives applications. The present review focuses briefly on the synthesis aspects and some of the physico-chemical properties of energetic materials of the class: (a) aminopyridine-N-oxides, (b) energetic azides, (c) high nitrogen content energetic materials, (d) imidazoles, (e) insensitive energetic materials, (f) oxidizers, (g) nitramines, (h) nitrate esters and (i) thermally stable explosives. A brief comment is also made on the emerging nitration concepts. This paper also reviews work done on primary explosives of current and futuristic interest based on energetic co-ordination compounds. Lead-free co-ordination compounds are the candidates of tomorrow's choice in view of their additional advantage of being eco-friendly. Another desirable attribute of lead free class of energetic compounds is the presence of almost equivalent quantity of fuel and oxidizer moieties. These compounds may find wide spectrum of futuristic applications in the area of energetic materials. The over all aim of the high energy materials research community is to develop the more powerful energetic materials/explosive formulations/propellant formulations in comparison to currently known benchmark materials/compositions. Therefore, an attempt is also made to highlight the important contributions made by the various researchers in the frontier areas energetic ballistic modifiers, energetic binders and energetic plasticizers.

  7. Electrostatic Discharge Sensitivity and Electrical Conductivity of Composite Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Michael A. Daniels; Daniel J. Prentice; Chelsea Weir; Michelle L. Pantoya; Gautham Ramachandran; Tim Dallas

    2013-02-01

    Composite energetic material response to electrical stimuli was investigated and a correlation between electrical conductivity and ignition sensitivity was examined. The composites consisted of micrometer particle aluminum combined with another metal, metal oxide, or fluoropolymer. Of the nine tested mixtures, aluminum with copper oxide was the only mixture to ignite by electrostatic discharge with minimum ignition energy (MIE) of 25 mJ and an electrical conductivity of 1246.25 nS; two orders of magnitude higher than the next composite. This study showed a similar trend in MIE for ignition triggered by a discharged spark compared with a thermal hot wire source.

  8. Synthesis of New Energetic Materials and Ionic Liquids Derived from Metronidazole

    OpenAIRE

    Romero, Miguel A.

    2016-01-01

    Simple and efficient synthetic procedures were established for the preparation of new energetic covalent compounds, salts, and protonated ionic liquids based on the readily available antimicrobial agent metronidazole. Some of these materials exhibit the desirable properties of energetic materials and energetic ionic liquids, such as low vapor pressure, low melting point, good chemical and thermal stability, and high energetic content. For each of the relevant compounds prepared, thermal stabi...

  9. Theoretical studies on energetic materials bearing pentaflurosulphyl (SF5) groups

    Indian Academy of Sciences (India)

    Li Xiao-Hong; Cui Hong-Ling; Ju Wei-Wei; Li Tong-Wei; Zhang Rui-Zhou; Yong Yong-Liang

    2014-07-01

    Heats of formation (HOF) for a series of energetic materials containing SF5 group were studied by density functional theory. Results show that HOFs increase with the augmention of field effects of substituted groups. Addition of furazan or furoxan ring increases HOF of the energetic materials. All the SF5-containing compounds have densities which are ∼0.19 g/cm3 higher than those containing -NH2 group. S-F bond is the trigger bond for the thermolysis process in the title compounds and bond dissociation energies of the weakest bonds range from 351.1 to 388.3 kJ/mol. Detonation velocities (D) and pressures (P) are evaluated by Kamlet-Jacobs equations with the calculated densities and HOFs. Results show that increasing the amount of furazan rings results in a larger D and P. Considering the detonation performance and thermal stability, eight compounds may be considered as potential candidates for high-energy density materials.

  10. ZnS nanostructure arrays: a developing material star.

    Science.gov (United States)

    Fang, Xiaosheng; Wu, Limin; Hu, Linfeng

    2011-02-01

    Semiconductor nanostructure arrays are of great scientific and technical interest because of the strong non-linear and electro-optic effects that occur due to carrier confinement in three dimensions. The use of such nanostructure arrays with tailored geometry, array density, and length-diameter-ratio as building blocks are expected to play a crucial role in future nanoscale devices. With the unique properties of a direct wide-bandgap semiconductor, such as the presence of polar surfaces, excellent transport properties, good thermal stability, and high electronic mobility, ZnS nanostructure arrays has been a developing material star. The research on ZnS nanostructure arrays has seen remarkable progress over the last five years due to the unique properties and important potential applications of nanostructure arrays, which are summarized here. Firstly, a survey of various methods to the synthesis of ZnS nanostructure arrays will be introduced. Next recent efforts on exploiting the unique properties and applications of ZnS nanostructure arrays are discussed. Potential future directions of this research field are also highlighted.

  11. One-dimensional Nanostructured Materials From Organic Precursor

    Institute of Scientific and Technical Information of China (English)

    K. F. Cai

    2005-01-01

    @@ 1Introduction One-dimensional nanostructured materials, such as nanowires, nanobelts, nanotubes and nanocables have been attracting a great research interest in the last decade due to their superior electrical, optical, mechanical and thermal properties, and many methods have been explored to synthesis of the materials, e.g., arc discharge, laser ablation, chemical vapor deposition, thermal evaporation, sol-gel method, template method and so on. In this work, we present a novel and simple method to one-dimensional nanostructured materials by pyrolysis of organic precursor.

  12. Modeling of space environment impact on nanostructured materials. General principles

    Science.gov (United States)

    Voronina, Ekaterina; Novikov, Lev

    2016-07-01

    In accordance with the resolution of ISO TC20/SC14 WG4/WG6 joint meeting, Technical Specification (TS) 'Modeling of space environment impact on nanostructured materials. General principles' which describes computer simulation methods of space environment impact on nanostructured materials is being prepared. Nanomaterials surpass traditional materials for space applications in many aspects due to their unique properties associated with nanoscale size of their constituents. This superiority in mechanical, thermal, electrical and optical properties will evidently inspire a wide range of applications in the next generation spacecraft intended for the long-term (~15-20 years) operation in near-Earth orbits and the automatic and manned interplanetary missions. Currently, ISO activity on developing standards concerning different issues of nanomaterials manufacturing and applications is high enough. Most such standards are related to production and characterization of nanostructures, however there is no ISO documents concerning nanomaterials behavior in different environmental conditions, including the space environment. The given TS deals with the peculiarities of the space environment impact on nanostructured materials (i.e. materials with structured objects which size in at least one dimension lies within 1-100 nm). The basic purpose of the document is the general description of the methodology of applying computer simulation methods which relate to different space and time scale to modeling processes occurring in nanostructured materials under the space environment impact. This document will emphasize the necessity of applying multiscale simulation approach and present the recommendations for the choice of the most appropriate methods (or a group of methods) for computer modeling of various processes that can occur in nanostructured materials under the influence of different space environment components. In addition, TS includes the description of possible

  13. On the propagation of Voigt waves in energetically active materials

    Science.gov (United States)

    Mackay, Tom G.; Lakhtakia, Akhlesh

    2016-11-01

    If Voigt-wave propagation is possible in a dissipative anisotropic dielectric material characterised by the permittivity dyadic \\mathop{\\varepsilon }\\limits\\raise{2pt=}, then it is also possible in the analogous energetically active material characterised by the permittivity dyadic \\mathop{\\tilde{\\varepsilon }}\\limits\\raise{2pt=}, where \\mathop{\\tilde{\\varepsilon }}\\limits\\raise{2pt=} is the hermitian conjugate of \\mathop{\\varepsilon }\\limits\\raise{2pt=}. This symmetry follows directly from a theoretical analysis of the necessary and sufficient conditions for Voigt-wave propagation in anisotropic materials. As a consequence of this symmetry, a porous dissipative material that exhibits Voigt-wave propagation can be used to construct a material that allows the propagation of Voigt waves with attendant linear gain in amplitude with propagation distance, by means of infiltration with an electrically or optically activated dye, for example. This phenomenon is captured by the Bruggeman formalism for homogenised composite materials based on isotropic dielectric component materials that are randomly distributed as oriented spheroidal particles.

  14. Controlled nanopatterning & modifications of materials by energetic ions

    Science.gov (United States)

    Sinha, O. P.

    2016-05-01

    Compound semiconductors (InP, InAs and GaSb) has been exposed to energetic 3kev Ar+ ions for a varying fluence range of 1013 ions/cm2 to 1018 ions/cm2 at room temperature. Morphological modifications of the irradiated surfaces have been investigated by Scanning Tunneling Microscopy (STM) in UHV conditions. It is observed that InP and GaSb have fluence dependent nanopattering e.g. nanoneedle, aligned nanodots, superimposed nanodots ripple like structures while InAs has little fluence dependent behaviour indicating materials dependent growth of features on irradiated surfaces. Moreover, surface roughness and wavelength of the features are also depending on the materials and fluences. The RMS surface roughness has been found to be increased rapidly in the early stage of irradiation followed by slower escalate rate and later tends to saturate indicating influence of the nonlinear processes.

  15. Hybrid nanostructured materials for high-performance electrochemical capacitors

    KAUST Repository

    Yu, Guihua

    2013-03-01

    The exciting development of advanced nanostructured materials has driven the rapid growth of research in the field of electrochemical energy storage (EES) systems which are critical to a variety of applications ranging from portable consumer electronics, hybrid electric vehicles, to large industrial scale power and energy management. Owing to their capability to deliver high power performance and extremely long cycle life, electrochemical capacitors (ECs), one of the key EES systems, have attracted increasing attention in the recent years since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review article describes the most recent progress in the development of nanostructured electrode materials for EC technology, with a particular focus on hybrid nanostructured materials that combine carbon based materials with pseudocapacitive metal oxides or conducting polymers for achieving high-performance ECs. This review starts with an overview of EES technologies and the comparison between various EES systems, followed by a brief description of energy storage mechanisms for different types of EC materials. This review emphasizes the exciting development of both hybrid nanomaterials and novel support structures for effective electrochemical utilization and high mass loading of active electrode materials, both of which have brought the energy density of ECs closer to that of batteries while still maintaining their characteristic high power density. Last, future research directions and the remaining challenges toward the rational design and synthesis of hybrid nanostructured electrode materials for next-generation ECs are discussed. © 2012 Elsevier Ltd.

  16. Atomic layer deposition of nanostructured materials

    CERN Document Server

    Pinna, Nicola

    2012-01-01

    Atomic layer deposition, formerly called atomic layer epitaxy, was developed in the 1970s to meet the needs of producing high-quality, large-area fl at displays with perfect structure and process controllability. Nowadays, creating nanomaterials and producing nanostructures with structural perfection is an important goal for many applications in nanotechnology. As ALD is one of the important techniques which offers good control over the surface structures created, it is more and more in the focus of scientists. The book is structured in such a way to fi t both the need of the expert reader (du

  17. Nanostructured materials, production and application in construction

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2014-12-01

    Full Text Available The paper considers characteristics of water-soluble high module silicate systems: based on polysilicates of alkali element called liquid glasses and the chains of their transformations from the lowest oligomers into the highest ones with further formation colloid solutions – silica sol. The authors describe the potentialities of the use of such systems as binders or modifying additives to produce different nanostructured silicate polymer concretes. There are examples of prospective application of liquid glass and water solutions of high module silicates in industrial areas and construction. Quantum-chemical calculations of the structure and properties of tetraphenylarsonium are given and heterogeneity of its functional groups is shown.

  18. Nanostructure materials for biosensing and bioimaging applications

    Science.gov (United States)

    Law, Wing Cheung

    not fully understand, three possible factors are concluded after systematic researches: (i) an increase of the absolute mass in each binding event, (ii) an increase in the bulk refractive index of the analyte, and (iii) coupling between the localized surface plasmon resonance (LSPR) of metallic nanoparticles and surface plasmon resonance (SPR) of the sensing film. Indeed, the role of plasmonic coupling in sensitivity enhancement is still an open question. In order to obtain a better understanding of this phenomenon, at the end of part I, extended studies were performed to investigate how the LSPR properties of metallic nanoparticle labels correlate with the enhancement factor. For this purpose, gold nanorods (Au-NRs) were chosen as the amplification labels because of the easy tunability of LSPR peak of Au-NR. After reading the "Result and Discussion" section, the readers will have better understanding of "plasmonic coupling" between the sensing film and the metallic labels with suitable operating laser source. In the second part of the thesis, the bioimaging part, the application of nanostructure materials in live cancer cell imaging and small animal imaging were demonstrated. There are different types of imaging technique available in laboratories and clinics: optical imaging, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), thermography and ultrasound imaging. Although such imaging techniques have been well developed and used over a decade, improving the sensitivity, enhancing the contrast, decreasing the acquisition time and reducing the toxicity of the contrast agent are highly desirable. For optical imaging, the scientists discovered that the use of near infrared fluorescence materials can assist the surgeon to locate the tumor, the nerve and the lymph node more accurately. For CT scan, the use of Au-NR as the contrast agent can improve the sensitivity. Iron oxide nanoparticle or gadolinium ion containing

  19. Molten salt destruction of energetic material wastes as an alternative to open burning

    Energy Technology Data Exchange (ETDEWEB)

    Upadhye, R.S.; Pruneda, C.O.; Watkins, B.E.

    1995-09-26

    The Lawrence Livermore National Laboratory in conjunction with the Energetic Materials Center ( a partnership of Lawrence Livermore and Sandia National Laboratories), is developing methods for the safe and environmentally sound destruction of explosives and propellants as a part of the Laboratory`s ancillary demilitarization mission. As a result of the end of the Cold War and the shift in emphasis to a smaller stockpile, many munitions, both conventional and nuclear, are scheduled for retirement and rapid dismantlement and demilitarization. Major components of these munitions are the explosives and propellants, or energetic materials. The Department of Energy has thousands of pounds of energetic materials which result from dismantlement operations at the Pantex Plant. The Department of Defense has several hundred million pounds of energetic materials in its demilitarization inventory, with millions more added each year. In addition, there are vast energetic materials demilitarization inventories world-wide, including those in the former Soviet Union and eastern Bloc countries. Although recycling and reusing is the preferred method of dealing with these surplus materials, there will always be the necessity of destroying intractable or unusable energetic materials. Traditionally, open bum/open detonation (OB/OD) has been the method of choice for the destruction of energetic materials. Public concerns and increasingly stringent environmental regulations have made open burning and open detonation of energetic materials increasingly costly and nearly unacceptable. Thus, the impetus to develop environmentally sound alternatives to dispose of energetic materials is great.

  20. Potential applications of nanostructured materials in nuclear waste management.

    Energy Technology Data Exchange (ETDEWEB)

    Braterman, Paul S. (The University of North Texas, Denton, TX); Phol, Phillip Isabio; Xu, Zhi-Ping (The University of North Texas, Denton, TX); Brinker, C. Jeffrey; Yang, Yi (University of New Mexico, Albuquerque, NM); Bryan, Charles R.; Yu, Kui; Xu, Huifang (University of New Mexico, Albuquerque, NM); Wang, Yifeng; Gao, Huizhen

    2003-09-01

    This report summarizes the results obtained from a Laboratory Directed Research & Development (LDRD) project entitled 'Investigation of Potential Applications of Self-Assembled Nanostructured Materials in Nuclear Waste Management'. The objectives of this project are to (1) provide a mechanistic understanding of the control of nanometer-scale structures on the ion sorption capability of materials and (2) develop appropriate engineering approaches to improving material properties based on such an understanding.

  1. Nanostructured Ion Storage Electrode Materials for Lithium Batteries and Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    S.R.S.Prabaharan

    2007-01-01

    1 Results Performance of lithium-ion batteries, electrochemical capacitors, and other electric-energy storage devices is not only determined simply by macroscopic chemical composition of their electrode, but also strongly affected by shape and size of the active materials. Nanostructured materials are distinguished from conventional polycrystalline materials by the nanometer size of the structural units that compose them, and they often exhibit properties that are drastically different from the conventi...

  2. Shock induced chemical reactions in energetic structural materials

    Science.gov (United States)

    Reding, Derek J.

    Energetic structural materials (ESMs) constitute a new class of materials that provide dual functions of strength and energetic characteristics. ESMs are typically composed of micron-scale or nano-scale intermetallic mixtures or mixtures of metals and metal oxides, polymer binders, and structural reinforcements. Voids are included to produce a composite with favorable chemical reaction characteristics. In this thesis, a continuum approach is used to simulate gas-gun or explosive loading experiments where a strong shock is induced in the ESM by an impacting plate. Algorithms are developed to obtain equations of state of mixtures. It is usually assumed that the shock loading increases the energy of the ESM and causes the ESM to reach the transition state. It is also assumed that the activation energy needed to reach the transition state is a function of the temperature of the mixture. In this thesis, it is proposed that the activation energy is a function of temperature and the stress state of the mixture. The incorporation of such an activation energy is selected in this thesis. Then, a multi-scale chemical reaction model for a heterogeneous mixture is introduced. This model incorporates reaction initiation, propagation, and extent of completed reaction in spatially heterogeneous distributions of reactants. A new model is proposed for the pore collapse of mixtures. This model is formulated by modifying the Carol, Holt, and Nesterenko spherically symmetric model to include mixtures and compressibility effects. Uncertainties in the model result from assumptions in formulating the models for continuum relationships and chemical reactions in mixtures that are distributed heterogeneously in space and in numerical integration of the resulting equations. It is important to quantify these uncertainties. In this thesis, such an uncertainty quantification is investigated by systematically identifying the physical processes that occur during shock compression of ESMs which are

  3. Prospective Symbiosis of Green Chemistry and Energetic Materials.

    Science.gov (United States)

    Kuchurov, Ilya V; Zharkov, Mikhail N; Fershtat, Leonid L; Makhova, Nina N; Zlotin, Sergey G

    2017-07-06

    A global increase in environmental pollution demands the development of new "cleaner" chemical processes. Among urgent improvements, the replacement of traditional hydrocarbon-derived toxic organic solvents with neoteric solvents less harmful for the environment is one of the most vital issues. As a result of the favorable combination of their unique properties, ionic liquids (ILs), dense gases, and supercritical fluids (SCFs) have gained considerable attention as suitable green chemistry media for the preparation and modification of important chemical compounds and materials. In particular, they have a significant potential in a specific and very important area of research associated with the manufacture and processing of high-energy materials (HEMs). These large-scale manufacturing processes, in which hazardous chemicals and extreme conditions are used, produce a huge amount of hard-to-dispose-of waste. Furthermore, they are risky to staff, and any improvements that would reduce the fire and explosion risks of the corresponding processes are highly desirable. In this Review, useful applications of almost nonflammable ILs, dense gases, and SCFs (first of all, CO2 ) for nitration and other reactions used for manufacturing HEMs are considered. Recent advances in the field of energetic (oxygen-balanced and hypergolic) ILs are summarized. Significant attention is paid to the SCF-based micronization techniques, which improve the energetic performance of HEMs through an efficient control of the morphology and particle size distribution of the HEM fine particles, and to useful applications of SCFs in HEM processing that makes them less hazardous. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Nanostructured Materials Developed for Solar Cells

    Science.gov (United States)

    Bailey, Sheila G.; Castro, Stephanie L.; Raffaelle, Ryne P.; Fahey, Stephen D.; Gennett, Thomas; Tin, Padetha

    2004-01-01

    There has been considerable investigation recently regarding the potential for the use of nanomaterials and nanostructures to increase the efficiency of photovoltaic devices. Efforts at the NASA Glenn Research Center have involved the development and use of quantum dots and carbon nanotubes to enhance inorganic and organic cell efficiencies. Theoretical results have shown that a photovoltaic device with a single intermediate band of states resulting from the introduction of quantum dots offers a potential efficiency of 63.2 percent. A recent publication extended the intermediate band theory to two intermediate bands and calculated a limiting efficiency of 71.7 percent. The enhanced efficiency results from converting photons of energy less than the band gap of the cell by an intermediate band. The intermediate band provides a mechanism for low-energy photons to excite carriers across the energy gap by a two-step process.

  5. Self-assembled peptide nanostructures for functional materials

    Science.gov (United States)

    Sardan Ekiz, Melis; Cinar, Goksu; Aref Khalily, Mohammad; Guler, Mustafa O.

    2016-10-01

    Nature is an important inspirational source for scientists, and presents complex and elegant examples of adaptive and intelligent systems created by self-assembly. Significant effort has been devoted to understanding these sophisticated systems. The self-assembly process enables us to create supramolecular nanostructures with high order and complexity, and peptide-based self-assembling building blocks can serve as suitable platforms to construct nanostructures showing diverse features and applications. In this review, peptide-based supramolecular assemblies will be discussed in terms of their synthesis, design, characterization and application. Peptide nanostructures are categorized based on their chemical and physical properties and will be examined by rationalizing the influence of peptide design on the resulting morphology and the methods employed to characterize these high order complex systems. Moreover, the application of self-assembled peptide nanomaterials as functional materials in information technologies and environmental sciences will be reviewed by providing examples from recently published high-impact studies.

  6. Nanostructured Mo-based electrode materials for electrochemical energy storage.

    Science.gov (United States)

    Hu, Xianluo; Zhang, Wei; Liu, Xiaoxiao; Mei, Yueni; Huang, Yunhui

    2015-04-21

    The development of advanced energy storage devices is at the forefront of research geared towards a sustainable future. Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport features, and attractive physicochemical properties. They have been extensively explored in various fields of energy storage and conversion. This review is focused largely on the recent progress in nanostructured Mo-based electrode materials including molybdenum oxides (MoO(x), 2 ≤ x ≤ 3), dichalconides (MoX2, X = S, Se), and oxysalts for rechargeable lithium/sodium-ion batteries, Mg batteries, and supercapacitors. Mo-based compounds including MoO2, MoO3, MoO(3-y) (0 energy storage systems because of their unique physicochemical properties, such as conductivity, mechanical and thermal stability, and cyclability. In this review, we aim to provide a systematic summary of the synthesis, modification, and electrochemical performance of nanostructured Mo-based compounds, as well as their energy storage applications in lithium/sodium-ion batteries, Mg batteries, and pseudocapacitors. The relationship between nanoarchitectures and electrochemical performances as well as the related charge-storage mechanism is discussed. Moreover, remarks on the challenges and perspectives of Mo-containing compounds for further development in electrochemical energy storage applications are proposed. This review sheds light on the sustainable development of advanced rechargeable batteries and supercapacitors with nanostructured Mo-based electrode materials.

  7. Micro-and nano-structured conducting polymeric materials

    Institute of Scientific and Technical Information of China (English)

    LU Gewu; CHEN Feng'en; WU Xufeng; QU Liangti; ZHANG Jiaxin; SHI Gaoquan

    2005-01-01

    Conducting polymeric materials with micro-/nano-structures have potential applications in fabrication of various optical, electronic, sensing and electrochemical devices. This is mainly because these materials not only possess the characteristics of conducting polymers, but also have special functions based on their micro- or nano-structures. In this review, we summarize the recent work on "soft" and "hard" template-guided syntheses of micro-/nano-structured conducting polymers and open up the prospects of the main trends in this field.

  8. Energetic salts with π-stacking and hydrogen-bonding interactions lead the way to future energetic materials.

    Science.gov (United States)

    Zhang, Jiaheng; Zhang, Qinghua; Vo, Thao T; Parrish, Damon A; Shreeve, Jean'ne M

    2015-02-04

    Among energetic materials, there are two significant challenges facing researchers: 1) to develop ionic CHNO explosives with higher densities than their parent nonionic molecules and (2) to achieve a fine balance between high detonation performance and low sensitivity. We report a surprising energetic salt, hydroxylammonium 3-dinitromethanide-1,2,4-triazolone, that exhibits exceptional properties, viz., higher density, superior detonation performance, and improved thermal, impact, and friction stabilities, then those of its precursor, 3-dinitromethyl-1,2,4-triazolone. The solid-state structure features of the new energetic salt were investigated with X-ray diffraction which showed π-stacking and hydrogen-bonding interactions that contribute to closer packing and higher density. According to the experimental results and theoretical analysis, the newly designed energetic salt also gives rise to a workable compromise in high detonation properties and desirable stabilities. These findings will enhance the future prospects for rational energetic materials design and commence a new chapter in this field.

  9. Nanostructure of gel-derived aluminosilicate materials.

    Science.gov (United States)

    Sinkó, Katalin; Hüsing, Nicola; Goerigk, Günter; Peterlik, Herwig

    2008-02-01

    In the present work, aluminosilicate aerogels prepared under various conditions were compared with respect to their nanostructures and porosity. The purpose of this investigation was to find a suitable way to predict the final product structure and to tailor a required texture. Several Al and Si precursors (Al nitrate, Al isopropoxide, Al acetate, tetraethoxysilane (TEOS), and sodium silicate) were used in our examinations; the solvent content (water and alcohols), surfactants, as well as the catalysts were varied. In addition, the aerogels were subjected to various heat treatments. Hybrid aerogels were synthesized by the addition of different polymers (poly(acrylic acid), polyvinyl acetate, and polydimethylsiloxane). Aluminosilicate and hybrid aerogel structures were investigated by 27Al MAS NMR, SAXS, SEM, and porosity measurements. Loose fractal structures with a good porosity and high Al incorporation can be achieved from TEOS and Al nitrate or isopropoxide via a sol-gel preparation route. The use of Al acetate led to compact aerogel structures independently of the Si precursor, the pH, and the catalyst.

  10. Nanostructured polymeric materials for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Di-Jia [Argonne National Lab. (ANL), Argonne, IL (United States; Yu, Luping [Argonne National Lab. (ANL), Argonne, IL (United States

    2013-03-01

    The objective of this project is to develop a new class of hydrogen storage adsorbent, nanostructured porous organic polymers (POPs), through collaboration between Argonne National Laboratory and The University of Chicago. POPs have excellent thermal stability and tolerance to gas contaminants such as moisture. They also have low skeleton density and high intrinsic porosity via covalent bonds, capable of maintaining specific surface area (SSA) during high pressure pelletizing for better volumetric density. Furthermore, they can be produced at a commercial scale with the existing industrial infrastructure. The team’s approach focused on improving hydrogen uptake capacity and the heat of adsorption by enhancing SSA, porosity control, and framework-adsorbate interactions through rational design and synthesis at the molecular level. The design principles aim at improving the following attributes of the polymers: (a) high SSA to provide sufficient interface with H2; (b) narrow pore diameter to enhance van der Waals interactions in the confined space; and (c) “metallic” features, either through π- conjugation or metal doping, to promote electronic orbital interactions with hydrogen.

  11. Structure and Stability of Deflagrations in Porous Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    stephen B. Margolis; Forman A. Williams

    1999-03-01

    Theoretical two-phase-flow analyses have recently been developed to describe the structure and stability of multi-phase deflagrations in porous energetic materials, in both confined and unconfined geometries. The results of these studies are reviewed, with an emphasis on the fundamental differences that emerge with respect to the two types of geometries. In particular, pressure gradients are usually negligible in unconfined systems, whereas the confined problem is generally characterized by a significant gas-phase pressure difference, or overpressure, between the burned and unburned regions. The latter leads to a strong convective influence on the burning rate arising from the pressure-driven permeation of hot gases into the solid/gas region and the consequent preheating of the unburned material. It is also shown how asymptotic models that are suitable for analyzing stability may be derived based on the largeness of an overall activation-energy parameter. From an analysis of such models, it is shown that the effects of porosity and two-phase flow are generally destabilizing, suggesting that degraded propellants, which exhibit greater porosity than their pristine counterparts, may be more readily subject to combustion instability and nonsteady deflagration.

  12. Kinetic stability and propellant performance of green energetic materials.

    Science.gov (United States)

    Rahm, Martin; Brinck, Tore

    2010-06-11

    A thorough theoretical investigation of four promising green energetic materials is presented. The kinetic stability of the dinitramide, trinitrogen dioxide, pentazole, and oxopentazole anions has been evaluated in the gas phase and in solution by using high-level ab initio and DFT calculations. Theoretical UV spectra, solid-state heats of formation, density, as well as propellant performance for the corresponding ammonium salts are reported. All calculated properties for dinitramide are in excellent agreement with experimental data. The stability of the trinitrogen dioxide anion is deemed sufficient to enable synthesis at low temperature, with a barrier for decomposition of approximately 27.5 kcal mol(-1) in solution. Oxopentazolate is expected to be approximately 1200 times more stable than pentazolate in solution, with a barrier exceeding 30 kcal mol(-1), which should enable handling at room temperature. All compounds are predicted to provide high specific impulses when combined with aluminum fuel and a polymeric binder, and rival or surpass the performance of a corresponding ammonium perchlorate based propellant. The investigated substances are also excellent monopropellant candidates. Further study and attempted synthesis of these materials is merited.

  13. Swift heavy ions for materials engineering and nanostructuring

    CERN Document Server

    Avasthi, Devesh Kumar

    2011-01-01

    Ion beams have been used for decades for characterizing and analyzing materials. Now energetic ion beams are providing ways to modify the materials in unprecedented ways. This book highlights the emergence of high-energy swift heavy ions as a tool for tailoring the properties of materials with nanoscale structures. Swift heavy ions interact with materials by exciting/ionizing electrons without directly moving the atoms. This opens a new horizon towards the 'so-called' soft engineering. The book discusses the ion beam technology emerging from the non-equilibrium conditions and emphasizes the power of controlled irradiation to tailor the properties of various types of materials for specific needs.

  14. Friction, impact, and electrostatic discharge sensitivities of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, P.S.; Hall, G.F.

    1985-05-31

    Impact, friction, and electrostatic discharge sensitivities of energetic materials (explosives and pyrotechnics) used or manufactured at Mound were tested by the ''one-shot'' method. The Bruceton statistical method was used to derive 50% initiation levels, and the results were compared. The materials tested include: PETN, HMX, Plastic Bonded Explosives (PBX), CP, TATB, RX26BB, RX26BH, barium styphnate, LX-15, LX-16, Ti/KClO/sub 4/, TiH/sub 0.65//KClO/sub 4/, TiH/sub 1.65//KClO/sub 4/, Fe/KClO/sub 4/, TiH/sub 1.75//B/CaCrO/sub 4/, Ti/B/CaCrO/sub 4/, B/CaCrO/sub 4/, TiH/sub 0.65//2B, TiH/sub 0.65//3B, 2Ti/B, TiH/sub 1.67//2B, Ti/2B, TiH/sub 1/67//3B, Ti/B, and Ti/3B. Some samples were investigated for aging effects, physical variables, and the effect of manufacturing paramters on sensitivities. The results show that in both friction and impact tests, CP and barium styphnate are the most sensitive; TiH/sub 1.65/KClO/sub 4/, LX-15, TATB and its related materials are the least sensitive; and other materials such as PETN and HMX are in the mid-range. In the electrostatic tests of Ti-based pyrotechnics, a decrease of sensitivity with increasing hydrogen concentration was observed. 20 refs., 12 figs., 7 tabs.

  15. The reapplication of energetic materials as boiler fuels

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, S.G.; Sclippa, G.C.; Ross, J.R. [and others

    1997-02-01

    Decommissioning of weapons stockpiles, off-specification production, and upgrading of weapons systems results in a large amount of energetic materials (EM) such as rocket propellant and primary explosives that need to be recycled or disposed of each year. Presently, large quantities of EM are disposed of in a process known as open-burn/open-detonation (OB/OD), which not only wastes their energy content, but may release large quantities of hazardous material into the environment. Here the authors investigate the combustion properties of several types of EM to determine the feasibility of reapplication of these materials as boiler fuels, a process that could salvage the energy content of the EM as well as mitigate any potential adverse environmental impact. Reapplication requires pretreatment of the fuels to make them safe to handle and to feed. Double-base nitrocellulose and nitroglycerin, trinitrotoluene (TNT), nitroguanidine, and a rocket propellant binder primarily composed of polybutidiene impregnated with aluminum flakes have been burned in a 100-kW downfired flow reactor. Most of these fuels have high levels of fuel-bound nitrogen, much of it bound in the form of nitrate groups, resulting in high NO{sub x} emissions during combustion. The authors have measured fuel-bound nitrate conversion efficiencies to NO{sub x} of up to 80%, suggesting that the nitrate groups do not follow the typical path of fuel nitrogen through HCN leading to NO{sub x}, but rather form NO{sub x} directly. They show that staged combustion is effective in reducing NO{sub x} concentrations in the postcombustion gases by nearly a factor of 3. In the rocket binder, measured aluminum particle temperatures in excess of 1700{degrees}C create high levels of thermal NO{sub x}, and also generate concern that molten aluminum particles could potentially damage boiler equipment. Judicious selection of the firing method is thus required for aluminum-containing materials.

  16. Novel thermal properties of nanostructured materials.

    Energy Technology Data Exchange (ETDEWEB)

    Eastman, J. A.

    1999-01-13

    A new class of heat transfer fluids, termed nanofluids, has been developed by suspending nanocrystalline particles in liquids. Due to the orders-of-magnitude larger thermal conductivities of solids compared to those of liquids such as water, significantly enhanced thermal properties are obtained with nanofluids. For example, an approximately 20% improvement in effective thermal conductivity is observed when 5 vol.% CuO nanoparticles are added to water. Even more importantly, the heat transfer coefficient of water under dynamic flow conditions is increased more than 15% with the addition of less than 1 vol.% CuO particles. The use of nanofluids could impact many industrial sectors, including transportation, energy supply and production, electronics, textiles, and paper production by, for example, decreasing pumping power needs or reducing heat exchanger sizes. In contrast to the enhancement in effective thermal transport rates that is obtained when nanoparticles are suspended in fluids, nanocrystalline coatings are expected to exhibit reduced thermal conductivities compared to coarse-grained coatings. Reduced thermal conductivities are predicted to arise because of a reduction in the mean free path of phonons due to presence of grain boundaries. This behavior, combined with improved mechanical properties, makes nanostructured zirconia coatings excellent candidates for future applications as thermal barriers. Yttria-stabilized zirconia (YSZ) thin films are being produced by metal-organic chemical vapor deposition techniques. Preliminary results have indicated that the thermal conductivity is reduced by approximately a factor-of-two at room temperature in 10 nm grain-sized YSZ compared to coarse-grained or single crystal YSZ.

  17. Quantitative Electron Tomography for Nanostructured Materials

    NARCIS (Netherlands)

    Friedrich, H.

    2009-01-01

    The controlled assembly of materials on the nanoscale has been a major focus of research across many scientific disciplines. In the nanometer size range, materials characteristics can be tuned not only by composition but more importantly by size and shape of constituent phases, giving rise to except

  18. Composite, nanostructured, super-hydrophobic material

    Science.gov (United States)

    D'Urso, Brian R.; Simpson, John T.

    2007-08-21

    A hydrophobic disordered composite material having a protrusive surface feature includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wherein the protrusive phase protrudes from the surface to form a protrusive surface feature, the protrusive feature being hydrophobic.

  19. STUDY OF THERMAL SENSITIVITY AND THERMAL EXPLOSION VIOLENCE OF ENERGETIC MATERIALS IN THE LLNL ODTX SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    HSU, P C; Hust, G; May, C; Howard, M; Chidester, S K; Springer, H K; Maienschein, J L

    2011-08-03

    Some energetic materials may explode at fairly low temperatures and the violence from thermal explosion may cause a significant damage. Thus it is important to understand the response of energetic materials to thermal insults for safe handling and storage of energetic materials. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory can measure times to explosion, lowest explosion temperatures, and determine kinetic parameters of energetic materials. Samples of different configurations can be tested in the system. The ODTX testing can also generate useful data for determining thermal explosion violence of energetic materials. We also performed detonation experiments of LX-10 in aluminum anvils to determine the detonation violence and validated the Zerilli Armstrong aluminum model. Results of the detonation experiments agreed well with the model prediction.

  20. Synthesis of New Energetic Materials and Ionic Liquids Derived from Metronidazole

    Directory of Open Access Journals (Sweden)

    Miguel A. Romero

    2016-01-01

    Full Text Available Simple and efficient synthetic procedures were established for the preparation of new energetic covalent compounds, salts, and protonated ionic liquids based on the readily available antimicrobial agent metronidazole. Some of these materials exhibit the desirable properties of energetic materials and energetic ionic liquids, such as low vapor pressure, low melting point, good chemical and thermal stability, and high energetic content. For each of the relevant compounds prepared, thermal stability was determined by differential scanning calorimetry. Some of these compounds may be considered promising precursors of pharmaceuticals such as antimicrobial, antiparasitic, antifungal, antineoplastic agents, or enzyme inhibitors.

  1. Ignition of Propellants Through Nanostructured Materials

    Science.gov (United States)

    2016-03-31

    case gaseous O2 was introduced in a coaxial flow at a rate of 7 Lit/min with a swirl motion in order to produce an effective fuel and oxidizer mixing...system should be robust, efficient , reliable, simple, low cost, and flexible. Also, an ignition system should initiate combustion under a broad range...discovered that the SWCNT material does not ignite well if wet, so we encapsulated the material to protect it from the fuel spray. To improve the

  2. Combination of lightweight elements and nanostructured materials for batteries.

    Science.gov (United States)

    Chen, Jun; Cheng, Fangyi

    2009-06-16

    In a society that increasingly relies on mobile electronics, demand is rapidly growing for both primary and rechargeable batteries that power devices from cell phones to vehicles. Existing batteries utilize lightweight active materials that use electrochemical reactions of ions such as H(+), OH(-) and Li(+)/Mg(2+) to facilitate energy storage and conversion. Ideal batteries should be inexpensive, have high energy density, and be made from environmentally friendly materials; batteries based on bulk active materials do not meet these requirements. Because of slow electrode process kinetics and low-rate ionic diffusion/migration, most conventional batteries demonstrate huge gaps between their theoretical and practical performance. Therefore, efforts are underway to improve existing battery technologies and develop new electrode reactions for the next generation of electrochemical devices. Advances in electrochemistry, surface science, and materials chemistry are leading to the use of nanomaterials for efficient energy storage and conversion. Nanostructures offer advantages over comparable bulk materials in improving battery performance. This Account summarizes our progress in battery development using a combination of lightweight elements and nanostructured materials. We highlight the benefits of nanostructured active materials for primary zinc-manganese dioxide (Zn-Mn), lithium-manganese dioxide (Li-Mn), and metal (Mg, Al, Zn)-air batteries, as well as rechargeable lithium ion (Li-ion) and nickel-metal hydride (Ni-MH) batteries. Through selected examples, we illustrate the effect of structure, shape, and size on the electrochemical properties of electrode materials. Because of their numerous active sites and facile electronic/ionic transfer and diffusion, nanostructures can improve battery efficiency. In particular, we demonstrate the properties of nanostructured active materials including Mg, Al, Si, Zn, MnO(2), CuV(2)O(6), LiNi(0.8)Co(0.2)O(2), LiFePO(4), Fe(2)O(3

  3. Nano-scale spinning detonation in condensed phase energetic materials

    Science.gov (United States)

    Zhakhovsky, Vasily; Budzevich, Mikalai; Landerville, Aaron; White, Carter; Oleynik, Ivan

    2013-06-01

    Single- and multi-headed spinning detonation waves are observed in molecular dynamics simulations of a condensed phase detonation of an energetic material (EM) confined in round tubes of different radii. The EM is modeled using a modified AB Reactive Empirical Bond Order potential. The thermochemistry and reactive equation of state are varied by adjusting the barrier height for the exothermic reaction AB +B --> A +BB. This allows us to study the evolution of the detonation-wave structure as a function of physico-chemical properties of the AB explosive. The detonation wave is found to exhibit a pulsating planar front in a tube of 8 nm radius, which later collapses due to the development of longitudinal perturbations. Upon increase of the tube's radius to 16 nm, the detonation wave structure is stabilized through the development of a single-headed spinning detonation. The spinning detonation displays a four-wave configuration, including incident, oblique, transverse, and contact shock waves. The contact shock generated by a contact discontinuity is observed for the first time in our MD simulations. A multi-headed turbulent-like detonation structure develops within tubes of larger radii, and exhibit features similar to those observed in gases.

  4. Synthesis and Investigation of Advanced Energetic Materials Based on Bispyrazolylmethanes.

    Science.gov (United States)

    Fischer, Dennis; Gottfried, Jennifer L; Klapötke, Thomas M; Karaghiosoff, Konstantin; Stierstorfer, Jörg; Witkowski, Tomasz G

    2016-12-23

    Herein we present the preparation and characterization of three new bispyrazolyl-based energetic compounds with great potential as explosive materials. The reaction of sodium 4-amino-3,5-dinitropyrazolate (5) with dimethyl iodide yielded bis(4-amino-3,5-dinitropyrazolyl)methane (6), which is a secondary explosive with high heat resistance (Tdec =310 °C). The oxidation of this compound afforded bis(3,4,5-trinitropyrazolyl)methane (7), which is a combined nitrogen- and oxygen-rich secondary explosive with very high theoretical and estimated experimental detonation performance (Vdet (theor)=9304 m s(-1) versus Vdet (exp)=9910 m s(-1) ) in the range of that of CL-20. Also, the thermal stability (Tdec =205 °C) and sensitivities of 7 are auspicious. The reaction of 6 with in situ generated nitrous acid yielded the primary explosive bis(4-diazo-5-nitro-3-oxopyrazolyl)methane (8), which showed superior properties to those of currently used diazodinitrophenol (DDNP). © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Shock-Induced Chemical Reactions in Structural Energetic Materials

    Science.gov (United States)

    Narayanan, V.; Lu, X.; Hanagud, S.

    2006-07-01

    Various powder mixtures like intermetallic mixtures and mixtures of metals and metal oxides have potential applications as structural energetic materials (SEMs). Technologies of varying the compositions and the powder sizes and their synthesis are being investigated to provide multiple desirable characteristics, like high strength and high energy content. In this paper, we formulate a model for SEMs for their application in shock conditions, in the framework of nonequilibrium thermodynamics and continuum mechanics. A mixture of Al and KClO4 is selected as the example for SEMs. A mixture, pore collapse and chemical reaction model are included. By adapting energy barriers for reaction as a function of temperature, particle size and pressure and introducing a relaxation mechanism in the reaction model, a shock-induced chemical reaction model is developed. The variation of the relaxation mechanism is also modeled. The initiation and propagation of chemical reactions are studied. The time and spatial dependency of chemical reaction on the shock wave conditions are investigated.

  6. Bis(nitroamino-1,2,4-triazolates): N-bridging strategy toward insensitive energetic materials.

    Science.gov (United States)

    Yin, Ping; Parrish, Damon A; Shreeve, Jean'ne M

    2014-11-17

    Modern energetic motifs for military and civilian applications are most often evaluated using various criteria, for example, energetic properties, production costs, and safety issues. Given this background, the design of energetic materials requires a deep understanding of both detonation performance and molecular stability. Here a new family of energetic bis(nitroamino-1,2,4-triazolates), which exhibit good thermal stabilities, excellent detonation properties, and low sensitivities, has been designed. Furthermore, two hydroxylammonium bis(azolates) with pyrazole and tetrazole backbones were synthesized, and they exhibit energetic properties analogous to the triazoles. This work highlights the application potential of N-bridged bis(azolates) as promising energetic materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Laser Propagation in Nanostructured Ultra-Low-Density Materials

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, K. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Colvin, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Yogo, A [Osaka Univ. (Japan). Inst. of Laser Engineering; Kemp, G. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matsukuma, H. [Osaka Univ. (Japan). Inst. of Laser Engineering; Tanaka, N. [Osaka Univ. (Japan). Inst. of Laser Engineering; Zhang, Z. [Osaka Univ. (Japan). Inst. of Laser Engineering; Koga, K. [Osaka Univ. (Japan). Inst. of Laser Engineering; Tosaki, S. [Osaka Univ. (Japan). Inst. of Laser Engineering; Nishimura, H. [Osaka Univ. (Japan). Inst. of Laser Engineering

    2016-03-15

    The nanostructure of very-low-density aerogels (< 10 mg/cm3) affects the laser heating and propagation of the subsequent heat front. Simulations treat these materials as an atomistic medium without any structure differentiating between near-solid-density material and voids. Thus, simulations fail to predict the effects of the aerogel’s physical micro or nanostructure on the laser-matter interaction. We have designed an experiment using the GEKKO XII laser and ILE diagnostics to characterize the ionization-wave propagation and x-ray yield from aerogel and mass-matched gaseous targets as the laser passes through each. By design, the gas and aerogel targets will have identical densities and identical effective ionization states.

  8. Nanostructured core-shell electrode materials for electrochemical capacitors

    Science.gov (United States)

    Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

    2016-11-01

    Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

  9. Magnetic Cluster States in Nanostructured Materials

    Energy Technology Data Exchange (ETDEWEB)

    Diandra Leslie-Pelecky

    2008-06-13

    The goal of this work is to fabricate model nanomaterials with different types of disorder and use atomic-scale characterization and macroscopic magnetization measurements to understand better how specific types of disorder affects macroscopic magnetic behavior. This information can be used to produce magnetic nanomaterials with specific properties for applications such as permanent magnets, soft magnetic material for motors and biomedical applications.

  10. Analysis of ignition of a porous energetic material

    Energy Technology Data Exchange (ETDEWEB)

    Telengator, A.M.; Williams, F.A. [Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Applied Mechanics and Engineering Sciences; Margolis, S.B. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility

    1998-04-01

    A theory of ignition is presented to analyze the effect of porosity on the time to ignition of a semi-infinite porous energetic solid subjected to a constant energy flux. An asymptotic perturbation analysis, based on the smallness of the gas-to-solid density ratio and the largeness of the activation energy, is utilized to describe the inert and transition stages leading to thermal runaway. As in the classical study of a nonporous solid, the transition stage consists of three spatial regions in the limit of large activation energy: a thin reactive-diffusive layer adjacent to the exposed surface of the material where chemical effects are first felt, a somewhat thicker transient-diffusive zone, and finally an inert region where the temperature field is still governed solely by conductive heat transfer. Solutions in each region are constructed at each order with respect to the density-ratio parameter and matched to one another using asymptotic matching principles. It is found that the effects of porosity provide a leading-order reduction in the time to ignition relative to that for the nonporous problem, arising from the reduced amount of solid material that must be heated and the difference in thermal conductivities of the solid and gaseous phases. A positive correction to the leading-order ignition-delay time, however, is provided by the convective flow of gas out of the solid, which stems from the effects of thermal expansion and removes energy from the system. The latter phenomenon is absent from the corresponding calculation for the nonporous problem and produces a number of modifications at the next order in the analysis arising from the relative transport effects associated with the gas flow.

  11. Realization of New and Enhanced Materials Properties Through Nanostructural Control

    Science.gov (United States)

    2006-05-15

    by modifying limits of integration over certain orientational variables [1,64,66]. Typical agreement between theory and experiment is shown below...must be different to realize an entropy enhancement, our preliminary experiments indicate that the difference can be realized in 400 ! , 5 . 3146-C168(75...Lecture: "Rational Desing of Nanostructured Organic Electro-Optic Materials". Conference-January 15-20, 2006--Conference on Photoresponsive Organics and

  12. Nanostructured Electrode Materials for Fuel Cells and Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    W.Sugimoto; T.Saida; Y.Takasu

    2007-01-01

    1 Results Owing to its electrochemical stability, catalytic activity and high electrical conductivity, ruthenium-based oxides have been realized in electrochemistry as excellent electrode materials with applications ranging from electrocatalysts for industrial electrolysis to high power energy storage. Recent studies have suggested that RuOx may have an active role in electrocatalysts for fuel cells.We have been engaged in the fundamental and practical study of nanostructured RuO2-based electrodes[1-5]....

  13. Hybrid Aluminum Composite Materials Based on Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Tatiana S. Koltsova

    2015-09-01

    Full Text Available We investigated formation of carbon nanofibers grown by chemical deposition (CVD method using an acetylene-hydrogen mixture on the surface of micron-sized aluminum powder particles. To obtain uniform distribution of the carbon nanostructures on the particles we deposited nickel catalyst on the surface by spraying from the aqueous solution of nickel nitrate. It was found that increasing the time of the synthesis lowers the rate of growth of carbon nanostructures due to the deactivation of the catalyst. The Raman spectroscopy measurements confirm the presence of disordered carbon corresponding to CNFs in the specimen. X-ray photoelectron spectroscopy showed the presence of aluminum carbide in the hot pressed samples. An aluminum composite material prepared using 1 wt.% CNFs obtained by uniaxial cold pressing and sintering showed 30% increase in the hardness compared to pure aluminum, whereas the composites prepared by hot pressing showed 80% increase in the hardness. Composite materials have satisfactory ductility. Thus, the aluminum based material reinforced with carbon nanostructures should be appropriate for creating high-strength and light compacts for aerospace and automotive applications and power engineering.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7355

  14. Electron Field Emission from Nanostructured Carbon Materials

    Science.gov (United States)

    Gupta, Sanju

    2005-03-01

    Fabricating small structures has almost become fashionable and the rationale is that reducing one or more dimensions below some critical length changes the systems' physical properties drastically, where nanocrystalline diamond (n-D) and carbon nanotubes (CNTs) in the class of advanced carbon materials serve model examples. Emission of electrons at room temperature - cold electron emitters - are of vital importance for a variety of vacuum microelectronic devices - electron microscopes, photo multipliers, X-ray generators, lamps, and flat panel displays and microwave cathodes. Electron emitters may lead to otherwise difficult to obtain advantages in performance and/or design. This is the driving force to investigate the carbon-related materials as cold cathodes. In this talk, the performance of various forms of carbon in thin film form including diamond, n-D, and vertically aligned CNTs as cold cathodes for their potential use in field emission displays (FEDs) in terms of I-V characteristics and corresponding spatial imaging will be presented. Physics based models such as, NEA, surface modification, geometric enhancement, and microstructure alteration due to particle bombardment, and doping, will be described to support the experimental observations of electron field enhancement (low turn-on voltage, high current and emission site density) and its reliability from the abovementioned carbon-related materials. Other vacuum device applications such as thermionic power generators will be mentioned briefly.

  15. High volume production of nanostructured materials

    Science.gov (United States)

    Ripley, Edward B.; Morrell, Jonathan S.; Seals, Roland D.; Ludtka, Gerard M.

    2009-10-13

    A system and method for high volume production of nanoparticles, nanotubes, and items incorporating nanoparticles and nanotubes. Microwave, radio frequency, or infrared energy vaporizes a metal catalyst which, as it condenses, is contacted by carbon or other elements such as silicon, germanium, or boron to form agglomerates. The agglomerates may be annealed to accelerate the production of nanotubes. Magnetic or electric fields may be used to align the nanotubes during their production. The nanotubes may be separated from the production byproducts in aligned or non-aligned configurations. The agglomerates may be formed directly into tools, optionally in compositions that incorporate other materials such as abrasives, binders, carbon-carbon composites, and cermets.

  16. X-ray characterisation of nanostructured materials

    DEFF Research Database (Denmark)

    Oddershede, Jette

    austenite produced using a novel method showed that CrN formed even at temperatures below 450± where the mobility of Cr is very low. 3) Carbon nanotubes, a non-crystalline material with a periodic structure. It was shown that the mean bulk structural properties of the nanotubes can be obtained from XRPD...... of the experi- mental XRPD patterns, the need for new interpretation methods has arisen. The method described in the present thesis is by no means new, in fact it was developed by Debye in 1915. However, the Debye method it is rather computationally heavy, so in practise it is only applicable to the X-ray char...

  17. Nanostructural Materials for Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Bronislaw Buczek

    2011-01-01

    Full Text Available The aim of this study was to assess of carbonaceous monoliths used for adsorption cooling systems. The carbonaceous monoliths prepared from coal precursors are obtained. The porous structure of monoliths was evaluated on the basis of nitrogen adsorption-desorption data. The investigated monoliths have significantly developed microporous structure. The large specific area of carbonaceous monoliths (about 2000 m2/g and volume of micropores are observed. Methanol adsorption isotherms and heat of wetting using methanol was determined. Results show that monoliths materials are high adsorption capacity of methanol and heat of wetting, which can improve of heat exchange and efficiency in processes of refrigeration and air conditioning.

  18. Recent advances in the molten salt destruction of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Pruneda, C. O., LLNL

    1996-09-01

    We have demonstrated the use of the Molten Salt Destruction (MSD) Process for destroying explosives, liquid gun propellant, and explosives-contaminated materials on a 1.5 kg of explosive/hr bench- scale unit (1, 2, 3, 4, 5). In our recently constructed 5 kg/hr pilot- scale unit we have also demonstrated the destruction of a liquid gun propellant and simulated wastes containing HMX (octogen). MSD converts the organic constituents of the waste into non-hazardous substances such as carbon dioxide, nitrogen, and water. Any inorganic constituents of the waste, such as metallic particles, are retained in the molten salt. The destruction of energetic materials waste is accomplished by introducing it, together with air, into a vessel containing molten salt (a eutectic mixture of sodium, potassium, and lithium carbonates). The following pure explosives have been destroyed in our bench-scale experimental unit located at Lawrence Livermore National Laboratory`s (LLNL) High Explosives Applications Facility (HEAF): ammonium picrate, HMX, K- 6 (keto-RDX), NQ, NTO, PETN, RDX, TATB, and TNT. In addition, the following compositions were also destroyed: Comp B, LX- IO, LX- 1 6, LX- 17, PBX-9404, and XM46 (liquid gun propellant). In this 1.5 kg/hr bench-scale unit, the fractions of carbon converted to CO and of chemically bound nitrogen converted to NO{sub x} were found to be well below 1%. In addition to destroying explosive powders and compositions we have also destroyed materials that are typical of residues which result from explosives operations. These include shavings from machined pressed parts of plastic-bonded explosives and sump waste containing both explosives and non-explosive debris. Based on the process data obtained on the bench-scale unit we designed and constructed a next-generation 5 kg/hr pilot-scale unit, incorporating LLNL`s advanced chimney design. The pilot unit has completed process implementation operations and explosives safety reviews. To date, in this

  19. Defect evolution and pore collapse in crystalline energetic materials

    Science.gov (United States)

    Barton, Nathan R.; Winter, Nicholas W.; Reaugh, John E.

    2009-04-01

    This work examines the use of crystal based continuum mechanics in the context of dynamic loading. In particular, we examine model forms and simulations which are relevant to pore collapse in crystalline energetic materials. Strain localization and the associated generation of heat are important for the initiation of chemical reactions in this context. The crystal mechanics based model serves as a convenient testbed for the interactions among wave motion, slip kinetics, defect generation kinetics and physical length scale. After calibration to available molecular dynamics and single crystal gas gun data for HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), the model is used to predict behaviors for the collapse of pores under various conditions. Implications for experimental observations are discussed. This document was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor Lawrence Livermore National Security, LLC, nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or Lawrence Livermore National Security, LLC. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or Lawrence Livermore National Security, LLC, and shall not be used for advertising or product endorsement purposes.

  20. Preparation and characterization of energetic materials coated superfine aluminum particles

    Science.gov (United States)

    Liu, Songsong; Ye, Mingquan; Han, Aijun; Chen, Xin

    2014-01-01

    This work is devoted to protect the activity of aluminum in solid rocket propellants by means of solvent/non-solvent method in which nitrocellulose (NC) and Double-11 (shortened form of double-base gun propellant, model 11) have been used as coating materials. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of coated Al particles. Other characterization data of coated and uncoated Al particles, such as infrared absorption spectrum, laser particle size analysis and the active aluminum content were also studied. The thermal behavior of pure and coated aluminum samples have also been studied by simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The results indicated that: superfine aluminum particles could be effectively coated with nitrocellulose and Double-11 through a solvent/non-solvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 20-50 nm. The active aluminum content of different coated samples was measured by means of oxidation-reduction titration method. The results showed that after being stored in room temperature and under 50% humidity condition for about 4months the active aluminum content of coated Al particles decreased from 99.8 to 95.8% (NC coating) and 99.2% (Double-11 coating) respectively. Double-11 coating layer had a much better protective effect. The TG-DTA and DSC results showed that the energy amount and energy release rate of NC coated and Double-11 coated Al particles were larger than those of the raw Al particles. Double-11 coated Al particles have more significant catalytic effect on the thermal decomposition characters of AP than that of NC coated Al particles. These features accorded with the energy release characteristics of solid propellant.

  1. Preparation and characterization of energetic materials coated superfine aluminum particles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Songsong; Ye, Mingquan, E-mail: liusong8366@gmail.com; Han, Aijun; Chen, Xin

    2014-01-01

    This work is devoted to protect the activity of aluminum in solid rocket propellants by means of solvent/non-solvent method in which nitrocellulose (NC) and Double-11 (shortened form of double-base gun propellant, model 11) have been used as coating materials. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of coated Al particles. Other characterization data of coated and uncoated Al particles, such as infrared absorption spectrum, laser particle size analysis and the active aluminum content were also studied. The thermal behavior of pure and coated aluminum samples have also been studied by simultaneous thermogravimetry–differential thermal analysis (TG–DTA) and differential scanning calorimetry (DSC). The results indicated that: superfine aluminum particles could be effectively coated with nitrocellulose and Double-11 through a solvent/non-solvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 20–50 nm. The active aluminum content of different coated samples was measured by means of oxidation–reduction titration method. The results showed that after being stored in room temperature and under 50% humidity condition for about 4months the active aluminum content of coated Al particles decreased from 99.8 to 95.8% (NC coating) and 99.2% (Double-11 coating) respectively. Double-11 coating layer had a much better protective effect. The TG–DTA and DSC results showed that the energy amount and energy release rate of NC coated and Double-11 coated Al particles were larger than those of the raw Al particles. Double-11 coated Al particles have more significant catalytic effect on the thermal decomposition characters of AP than that of NC coated Al particles. These features accorded with the energy release characteristics of solid propellant.

  2. Liquid Nitrogen and Water Jet Milling of Energetic Material Production Wastes

    Science.gov (United States)

    1996-05-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP017711 TITLE: Liquid Nitrogen and Water Jet Milling of Energetic...NITROGEN AND WATER JET MILLING OF ENERGETIC MATERIAL PRODUCTION WASTES Roger L. Schneider Rho Sigma Associates, Inc. Whitefish Bay, WI 53217-5968 USA 414

  3. Probing the Dynamics of Ultra-Fast Condensed State Reactions in Energetic Materials

    Science.gov (United States)

    Piekiel, Nicholas William

    2012-01-01

    Energetic materials (EMs) are substances with a high amount of stored energy and the ability to release that energy at a rapid rate. Nanothermites and green organic energetics are two classes of EMs which have gained significant interest as they each have desirable properties over traditional explosives. These systems also possess downfalls, which…

  4. Scaling Laws for van der Waals Interactions in Nanostructured Materials

    Science.gov (United States)

    Gobre, Vivekanand; Tkatchenko, Alexandre

    2014-03-01

    Van der Waals (vdW) forces originate from interactions between fluctuating multipoles in matter and play a significant role in the structure and stability of nanostructured materials. Many models used to describe vdW interactions in nanomaterials are based on a simple pairwise-additive approximation, neglecting the strong electrodynamic response effects caused by long-range fluctuations in matter. We develop and utilize an efficient microscopic method to demonstrate that vdW interactions in nanomaterials act at distances greater than typically assumed, and can be characterized by different scaling laws depending on the dimensionality and size of the system. Specifically, we study the behaviour of vdW interactions in single-layer and multilayer graphene, fullerenes of varying size, single-wall carbon nanotubes and graphene nanoribbons. As a function of nanostructure size, the van der Waals coefficients follow unusual trends for all of the considered systems, and deviate significantly from the conventionally employed pairwise-additive picture. We propose that the peculiar van der Waals interactions in nanostructured materials could be exploited to control their self-assembly.

  5. Surface modification of microfibrous materials with nanostructured carbon

    Energy Technology Data Exchange (ETDEWEB)

    Krasnikova, Irina V., E-mail: tokareva@catalysis.ru [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk 634050 (Russian Federation); Mishakov, Ilya V.; Vedyagin, Aleksey A. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk 634050 (Russian Federation); Bauman, Yury I. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk 630090 (Russian Federation); Korneev, Denis V. [State Research Center of Virology and Biotechnology VECTOR, Koltsovo, Novosibirsk Region 630559 (Russian Federation)

    2017-01-15

    The surface of fiberglass cloth, carbon and basalt microfibers was modified with carbon nanostructured coating via catalytic chemical vapor deposition (CCVD) of 1,2-dichloroethane. Incipient wetness impregnation and solution combustion synthesis (SCS) methods were used to deposit nickel catalyst on the surface of microfibrous support. Prepared NiO/support samples were characterized by X-ray diffraction analysis and temperature-programmed reduction. The samples of resulted hybrid materials were studied by means of scanning and transmission electron microscopies as well as by low-temperature nitrogen adsorption. The nature of the support was found to have considerable effect on the CCVD process peculiarities. High yield of nanostructured carbon with largest average diameter of nanofibers within the studied series was observed when carbon microfibers were used as a support. This sample characterized with moderate surface area (about 80 m{sup 2}/g after 2 h of CCVD) shows the best anchorage effect. Among the mineral supports, fiberglass tissue was found to provide highest carbon yield (up to 3.07 g/g{sub FG}) and surface area (up to 344 m{sup 2}/g) due to applicability of SCS method for Ni deposition. - Highlights: • The microfibers of different nature were coated with nanostructured carbon layer. • Features of CNF growth and characteristics of hybrid materials were studied. • Appropriate anchorage of CNF layer on microfiber’s surface was demonstrated.

  6. Coupled thermal/chemical/mechanical modeling of energetic materials in ALE3D

    Science.gov (United States)

    Nichols, A. L.; Couch, R.; Maltby, J. D.; McCallen, R. C.; Otero, I.

    1996-01-01

    We must improve our ability to model the response of energetic materials to thermal stimuli and the processes involved in the energetic response. We have developed and used a time step option to efficiently and accurately compute the hours that the energetic material can take to react. Since on these longer film scales, materials can be expected to have significant motion, it is even more important to provide high-order advection for all components, including the chemical species. We show an example cook-off problem to illustrate these capabilities.

  7. Novel hybrid nanostructured materials of magnetite nanoparticles and pectin

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, Saurabh [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India); Dutta, Raj Kumar, E-mail: duttafcy@iitr.ernet.i [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)

    2011-04-15

    A novel hybrid nanostructured material comprising superparamagnetic magnetite nanoparticles (MNPs) and pectin was synthesized by crosslinking with Ca{sup 2+} ions to form spherical calcium pectinate nanostructures, referred as MCPs, which were typically found to be 100-150 nm in size in dried condition, confirmed from transmission electron microscopy and scanning electron microscopy. The uniform size distribution was revealed from dynamic light scattering measurement. In aqueous medium the MCPs showed swelling behavior with an average size of 400 nm. A mechanism of formation of spherical MCPs is outlined constituting a MNP-pectin interface encapsulated by calcium pectinate at the periphery, by using an array of characterization techniques like zeta potential, thermogravimetry, Fourier transformed infrared and X-ray photoelectron spectroscopy. The MCPs were stable in simulated gastrointestinal fluid and ensured minimal loss of magnetic material. They exhibited superparamagnetic behavior, confirmed from zero field cooled and field cooled profiles and showed high saturation magnetization (M{sub s}) of 46.21 emu/g at 2.5 T and 300 K. M{sub s} decreased with increasing precursor pectin concentrations, attributed to quenching of magnetic moments by formation of a magnetic dead layer on the MNPs. - Research highlights: > In the present investigation we have developed a facile route to synthesize a novel, low cost calcium pectinate nanostructure functionalized with SPIONs (magnetite nanoparticles). > Though there are sufficient scientific illustrations on polymer as well as biopolymers coated on SPIONs for various biomedical applications, the one presented here, is novel of its kind as it is considered to offer a new dimension to the magnetic responsive properties of calcium pectinate nanomaterials towards biomedical applications, especially as a potential carrier for magnetically targeted drug delivery to colon specific sites. > The synthesis of these nanostructured

  8. Thermal properties of graphene and nanostructured carbon materials

    Science.gov (United States)

    Balandin, Alexander A.

    2011-08-01

    Recent years have seen a rapid growth of interest by the scientific and engineering communities in the thermal properties of materials. Heat removal has become a crucial issue for continuing progress in the electronic industry, and thermal conduction in low-dimensional structures has revealed truly intriguing features. Carbon allotropes and their derivatives occupy a unique place in terms of their ability to conduct heat. The room-temperature thermal conductivity of carbon materials span an extraordinary large range -- of over five orders of magnitude -- from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. Here, I review the thermal properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. Special attention is given to the unusual size dependence of heat conduction in two-dimensional crystals and, specifically, in graphene. I also describe the prospects of applications of graphene and carbon materials for thermal management of electronics.

  9. Advanced Nanostructured Anode Materials for Sodium-Ion Batteries.

    Science.gov (United States)

    Wang, Qidi; Zhao, Chenglong; Lu, Yaxiang; Li, Yunming; Zheng, Yuheng; Qi, Yuruo; Rong, Xiaohui; Jiang, Liwei; Qi, Xinguo; Shao, Yuanjun; Pan, Du; Li, Baohua; Hu, Yong-Sheng; Chen, Liquan

    2017-09-19

    Sodium-ion batteries (NIBs), due to the advantages of low cost and relatively high safety, have attracted widespread attention all over the world, making them a promising candidate for large-scale energy storage systems. However, the inherent lower energy density to lithium-ion batteries is the issue that should be further investigated and optimized. Toward the grid-level energy storage applications, designing and discovering appropriate anode materials for NIBs are of great concern. Although many efforts on the improvements and innovations are achieved, several challenges still limit the current requirements of the large-scale application, including low energy/power densities, moderate cycle performance, and the low initial Coulombic efficiency. Advanced nanostructured strategies for anode materials can significantly improve ion or electron transport kinetic performance enhancing the electrochemical properties of battery systems. Herein, this Review intends to provide a comprehensive summary on the progress of nanostructured anode materials for NIBs, where representative examples and corresponding storage mechanisms are discussed. Meanwhile, the potential directions to obtain high-performance anode materials of NIBs are also proposed, which provide references for the further development of advanced anode materials for NIBs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Applications of Nanostructured Carbon Materials in Constructions: The State of the Art

    Directory of Open Access Journals (Sweden)

    Shu-Nan Lu

    2015-01-01

    Full Text Available The most recent studies on the applications of nanostructured carbon materials, including carbon nanotubes, carbon nanofibers, and graphene oxides, in constructions are presented. First, the preparation of nanostructured carbon/infrastructure material composites is summarized. This part is mainly focused on how the nanostructured carbon materials were mixed with cementitious or asphalt matrix to realize a good dispersion condition. Several methods, including high speed melting mixing, surface treatment, and aqueous solution with surfactants and sonication, were introduced. Second, the applications of the carbon nanostructured materials in constructions such as mechanical reinforcement, self-sensing detectors, self-heating element for deicing, and electromagnetic shielding component were systematically reviewed. This paper not only helps the readers understand the preparation process of the carbon nanostructured materials/infrastructure material composites but also sheds some light on the state-of-the-art applications of carbon nanostructured materials in constructions.

  11. Ammonia Oxide as a Building Block for High-Performance and Insensitive Energetic Materials.

    Science.gov (United States)

    Tang, Yongxing; Mitchell, Lauren A; Imler, Gregory H; Parrish, Damon A; Shreeve, Jean'ne M

    2017-05-15

    3,5-Dinitrimino-1,2,4-triazole (2) with three protons has the potential of deprotonation to form energetic salts. Neutralization of 2 with 50 % hydroxylamine in varying molar ratios leads to the formation of the corresponding mono/dihydroxylammonium energetic salts. Additionally compound 5, an ammonia oxide adduct of dihydroxylammonium 3,5-dinitramino-1,2,4-triazolate, was prepared when excess hydroxylamine was used. The structures of 3-5 are supported by single-crystal X-ray diffraction. The energetic properties of the new materials are competitive. Utilization of ammonia oxide adducts in hydroxylammonium energetic salts could lead to future practical applications as energetic materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Furazans with Azo Linkages: Stable CHNO Energetic Materials with High Densities, Highly Energetic Performance, and Low Impact and Friction Sensitivities.

    Science.gov (United States)

    Qu, Yanyang; Zeng, Qun; Wang, Jun; Ma, Qing; Li, Hongzhen; Li, Haibo; Yang, Guangcheng

    2016-08-22

    Various highly energetic azofurazan derivatives were synthesized by simple and efficient chemical routes. These nitrogen-rich materials were fully characterized by FTIR spectroscopy, elemental analysis, multinuclear NMR spectroscopy, and high-resolution mass spectrometry. Four of them were further confirmed structurally by single-crystal X-ray diffraction. These compounds exhibit high densities, ranging from 1.62 g cm(-3) up to a remarkably high 2.12 g cm(-3) for nitramine-substituted azofurazan DDAzF (2), which is the highest yet reported for an azofurazan-based CHNO energetic compound and is a consequence of the formation of strong intermolecular hydrogen-bonding networks. From the heats of formation, calculated with Gaussian 09, and the experimentally determined densities, the energetic performances (detonation pressure and velocities) of the materials were ascertained with EXPLO5 v6.02. The results suggest that azofurazan derivatives exhibit excellent detonation properties (detonation pressures of 21.8-46.1 GPa and detonation velocities of 6602-10 114 m s(-1) ) and relatively low impact and friction sensitivities (6.0-80 J and 80-360 N, respectively). In particular, they have low electrostatic spark sensitivities (0.13-1.05 J). These properties, together with their high nitrogen contents, make them potential candidates as mechanically insensitive energetic materials with high-explosive performance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Thermal and Thermoelectric Properties of Nanostructured Materials and Interfaces

    Science.gov (United States)

    Liao, Hao-Hsiang

    Many modern technologies are enabled by the use of thin films and/or nanostructured composite materials. For example, many thermoelectric devices, solar cells, power electronics, thermal barrier coatings, and hard disk drives contain nanostructured materials where the thermal conductivity of the material is a critical parameter for the device performance. At the nanoscale, the mean free path and wavelength of heat carriers may become comparable to or smaller than the size of a nanostructured material and/or device. For nanostructured materials made from semiconductors and insulators, the additional phonon scattering mechanisms associated with the high density of interfaces and boundaries introduces additional resistances that can significantly change the thermal conductivity of the material as compared to a macroscale counterpart. Thus, better understanding and control of nanoscale heat conduction in solids is important scientifically and for the engineering applications mentioned above. In this dissertation, I discuss my work in two areas dealing with nanoscale thermal transport: (1) I describe my development and advancement of important thermal characterization tools for measurements of thermal and thermoelectric properties of a variety of materials from thin films to nanostructured bulk systems, and (2) I discuss my measurements on several materials systems done with these characterization tools. First, I describe the development, assembly, and modification of a time-domain thermoreflectance (TDTR) system that we use to measure the thermal conductivity and the interface thermal conductance of a variety of samples including nanocrystalline alloys of Ni-Fe and Co-P, bulk metallic glasses, and other thin films. Next, a unique thermoelectric measurement system was designed and assembled for measurements of electrical resistivity and thermopower of thermoelectric materials in the temperature range of 20 to 350 °C. Finally, a commercial Anter Flashline 3000 thermal

  14. In situ transmission electron microscopy experimentation of nanostructured materials

    Science.gov (United States)

    Alducin, Diego

    Due to the remarkable mechanical and electrical properties some nanostructured materials possess, it is important to be able to quantitatively characterize how these materials react under different types of stimulus. In situ transmission electron microscopy is a unique technique that allows the user to fully observe and record the crystallographic behavior of such materials undergoing a variety of tests. The crystallographic orientations silver nanowires were mapped in order to understand the structure and facets due to its geometry. Measuring the toughness and yield of the material led us to understand the anisotropic behavior of AgNWs. Depending on whether a load is applied to either a boundary between facets or on a facet will change the mechanical strength of the nanowire. By measuring the resistivity of the this material during deformation has also led us to understand that the intrinsic defects in the crystal structure of nanowires will change the way the material reacts to an electric potential. We have been also able to completely map the crystallographic orientations of very complex geometries of gold nanoparticles and characterize the weak forces involved in the manipulation if these nanoparticles. Finally, the elasticity of MoS2 was tested and found to be exponentially dependent upon the thickness of the nanosheets. However, the resistivity of this material does not seem to be affected by any type of deformation it is subjected to. The complete categorization of how materials interact with external stimulus while comparing the changes observed in its crystal structure is essential to understanding the underlying properties of nanostructured materials, which would not be possible without in situ transmisison electron microscopy experimentation.

  15. Self-assembled peptide nanostructures for functional materials.

    Science.gov (United States)

    Ekiz, Melis Sardan; Cinar, Goksu; Khalily, Mohammad Aref; Guler, Mustafa O

    2016-10-07

    Nature is an important inspirational source for scientists, and presents complex and elegant examples of adaptive and intelligent systems created by self-assembly. Significant effort has been devoted to understanding these sophisticated systems. The self-assembly process enables us to create supramolecular nanostructures with high order and complexity, and peptide-based self-assembling building blocks can serve as suitable platforms to construct nanostructures showing diverse features and applications. In this review, peptide-based supramolecular assemblies will be discussed in terms of their synthesis, design, characterization and application. Peptide nanostructures are categorized based on their chemical and physical properties and will be examined by rationalizing the influence of peptide design on the resulting morphology and the methods employed to characterize these high order complex systems. Moreover, the application of self-assembled peptide nanomaterials as functional materials in information technologies and environmental sciences will be reviewed by providing examples from recently published high-impact studies.

  16. Experimental characterization of energetic material dynamics for multiphase blast simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Beresh, Steven Jay; Wagner, Justin L.; Kearney, Sean Patrick; Wright, Elton K.; Baer, Melvin R.; Pruett, Brian Owen Matthew

    2011-09-01

    Currently there is a substantial lack of data for interactions of shock waves with particle fields having volume fractions residing between the dilute and granular regimes, which creates one of the largest sources of uncertainty in the simulation of energetic material detonation. To close this gap, a novel Multiphase Shock Tube has been constructed to drive a planar shock wave into a dense gas-solid field of particles. A nearly spatially isotropic field of particles is generated in the test section by a gravity-fed method that results in a spanwise curtain of spherical 100-micron particles having a volume fraction of about 19%. Interactions with incident shock Mach numbers of 1.66, 1.92, and 2.02 were achieved. High-speed schlieren imaging simultaneous with high-frequency wall pressure measurements are used to reveal the complex wave structure associated with the interaction. Following incident shock impingement, transmitted and reflected shocks are observed, which lead to differences in particle drag across the streamwise dimension of the curtain. Shortly thereafter, the particle field begins to propagate downstream and spread. For all three Mach numbers tested, the energy and momentum fluxes in the induced flow far downstream are reduced about 30-40% by the presence of the particle field. X-Ray diagnostics have been developed to penetrate the opacity of the flow, revealing the concentrations throughout the particle field as it expands and spreads downstream with time. Furthermore, an X-Ray particle tracking velocimetry diagnostic has been demonstrated to be feasible for this flow, which can be used to follow the trajectory of tracer particles seeded into the curtain. Additional experiments on single spherical particles accelerated behind an incident shock wave have shown that elevated particle drag coefficients can be attributed to increased compressibility rather than flow unsteadiness, clarifying confusing results from the historical database of shock tube

  17. Experimental characterization of energetic material dynamics for multiphase blast simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Beresh, Steven Jay; Wagner, Justin L.; Kearney, Sean Patrick; Wright, Elton K.; Baer, Melvin R.; Pruett, Brian Owen Matthew

    2011-09-01

    Currently there is a substantial lack of data for interactions of shock waves with particle fields having volume fractions residing between the dilute and granular regimes, which creates one of the largest sources of uncertainty in the simulation of energetic material detonation. To close this gap, a novel Multiphase Shock Tube has been constructed to drive a planar shock wave into a dense gas-solid field of particles. A nearly spatially isotropic field of particles is generated in the test section by a gravity-fed method that results in a spanwise curtain of spherical 100-micron particles having a volume fraction of about 19%. Interactions with incident shock Mach numbers of 1.66, 1.92, and 2.02 were achieved. High-speed schlieren imaging simultaneous with high-frequency wall pressure measurements are used to reveal the complex wave structure associated with the interaction. Following incident shock impingement, transmitted and reflected shocks are observed, which lead to differences in particle drag across the streamwise dimension of the curtain. Shortly thereafter, the particle field begins to propagate downstream and spread. For all three Mach numbers tested, the energy and momentum fluxes in the induced flow far downstream are reduced about 30-40% by the presence of the particle field. X-Ray diagnostics have been developed to penetrate the opacity of the flow, revealing the concentrations throughout the particle field as it expands and spreads downstream with time. Furthermore, an X-Ray particle tracking velocimetry diagnostic has been demonstrated to be feasible for this flow, which can be used to follow the trajectory of tracer particles seeded into the curtain. Additional experiments on single spherical particles accelerated behind an incident shock wave have shown that elevated particle drag coefficients can be attributed to increased compressibility rather than flow unsteadiness, clarifying confusing results from the historical database of shock tube

  18. Molten salt destruction of energetic material wastes as an alternative to open burning

    Energy Technology Data Exchange (ETDEWEB)

    Upadhye, R.S.; Brummond, W.A.; Pruneda, C.O.; Watkins, B.E.

    1994-09-08

    The Lawrence Livermore National Laboratory in conjunction with the Energetic Materials Center (a partnership of Lawrence Livermore and Sandia National Laboratories), is developing methods for the safe and environmentally sound destruction of explosives and propellants as a part of the Laboratory`s ancillary demilitarization mission. As a result of the end of the Cold War and the shift in emphasis to a smaller stockpile, many munitions, both conventional and nuclear, are scheduled for retirement and rapid dismantlement and demilitarization. major components of these munitions are the explosives and propellants, or energetic materials. The Department of Energy has thousands of pounds of energetic materials which result from dismantlement operations at the Pantex Plant. The Department of Defense has several hundred million pounds of energetic materials in its demilitarization inventory, with millions more added each year.

  19. Nanostructured materials: A novel approach to enhanced performance. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Korth, G.E.; Froes, F.H.; Suryanarayana, C. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)] [and others

    1996-05-01

    Nanostuctured materials are an emerging class of materials that can exhibit physical and mechanical characteristics often exceeding those exhibited by conventional course grained materials. A number of different techniques can be employed to produce these materials. In this program, the synthesis methods were (a) mechanical alloying , (b) physical vapor deposition, and (c) plasma processing. The physical vapor deposition and plasma processing were discontinued after initial testing with subsequent efforts focused on mechanical alloying. The major emphasis of the program was on the synthesis, consolidation, and characterization of nanostructured Al-Fe, Ti-Al, Ti-Al-Nb, and Fe-Al by alloying intermetallics with a view to increase their ductilities. The major findings of this project are reported.

  20. Indirect ignition of energetic materials with laser-driven flyer plates.

    Science.gov (United States)

    Dean, Steven W; De Lucia, Frank C; Gottfried, Jennifer L

    2017-01-20

    The impact of laser-driven flyer plates on energetic materials CL-20, PETN, and TATB has been investigated. Flyer plates composed of 25 μm thick Al were impacted into the energetic materials at velocities up to 1.3 km/s. The flyer plates were accelerated by means of an Nd:YAG laser pulse. The laser pulse generates rapidly expanding plasma between the flyer plate foil and the substrate to which it is adhered. As the plasma grows, a section of the metal foil is ejected at high speed, forming the flyer plate. The velocity of the flyer plate was determined using VISAR, time of flight, and high-speed video. The response of the energetic material to impact was determined by light emission recorded by an infrared-sensitive photodiode. Following post-impact analysis of the impacted energetic material, it was hypothesized that the light emitted by the material after impact is not due to the impact of the flyer itself but rather is caused by the decomposition of energetic material ejected (via the shock of flyer plate impact) into a cloud of hot products generated during the launch of the flyer plate. This hypothesis was confirmed through schlieren imaging of a flyer plate launch, clearly showing the ejection of hot gases and particles from the region surrounding the flyer plate launch and the burning of the ejected energetic material particles.

  1. Compatibility Study of DNTF with Some Insensitive Energetic Materials and Inert Materials

    Science.gov (United States)

    Li, Xi; Wang, Bo-Liang; Lin, Qiu-Han; Chen, Li-Ping

    2016-10-01

    The compatibility of 3,4-dinitrofurazanfuroxan (DNTF) with insensitive energetic materials and inert materials was studied in detail using differential scanning calorimetry (DSC). 2,4,6-Trinitrotoluene (TNT), 2,4,6-triamino-1,3,5-trinitrobenzene (TATB), 3-nitro-1,2,4-triazol-5-one (NTO), 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), 2,6-diamino-3,5-dinitropyridine-1-oxide (ANPyO), and 5-amino-1H-tetrazole nitrate (5-ATEZN) are used as insensitive energetic materials, and polymer(vinyl acetate) (PVAC), hydroxyl-terminated polybutadiene (HTPB), dinoctylsebacate (DOS), 2,4-dinitrotoluene (DNT), and wax are used as inert materials. The results show that DNTF/TNT and DNTF/5-ATEZN possess good compatibility, DNTF/NTO and DNTF/TATB have moderate compatibility, and the compatibility of DNTF/LLM-105 and DNTF/PVAC is poor; in addition, DNTF/ANPyO, DNTF/HTPB, DNTF/DNT, DNTF/DOS, and DNTF/wax have bad compatibility.

  2. Semiconductive Nanostructures - Materials for Spinelectronics: New Data Bank Requirement

    Directory of Open Access Journals (Sweden)

    Paata J Kervalishvili

    2007-12-01

    Full Text Available Nanoscience, the interdisciplinary science that draws on physics, chemistry, biology, and computational mathematics, is still in its infancy. Control and manipulation on a nanometric scale allow the fabrication of nanostructures, the properties of which are mainly determined by quantum mechanics and differ considerably from that of the common crystalline state. Nanostructures constructed from inorganic solids such as semiconductors have new electronic and optical properties because of their size and quantization effects [1, 2]. The quantization effects reflect the fundamental characteristics of structures as soon as their size falls below a certain limit. An example of the simplest nanostructure is the quantum dot formed from the energy well of certain semiconductor materials with 5-10nm thickness sandwiched between other semiconductors with normal properties. Quantum dots, for example, have led to important novel technology for lasers, optical sensors, and other electronic devices. The application of nanolayers to data storage, switching, lighting, and other devices can lead to substantially new hardware, for example, energy cells, and eventually to the quantum-based internet. Nanoscience and nanotechnology encompass the development of nano-spinelectronics, spinelectronics materials production, and nano-spinelectronic measuring devices and technologies. Nano-spinelectronics, based on usage of magnetic semiconductors, represents a new and emerging area of science and engineering of the 21st century. It is a primary example of the creation and enhancement of new materials and devices for information technologies, operating with charge and spin degrees of freedom of carriers, free from present-day limitations. This new multi-disciplinary direction of science and technology is very much in need of support from new data banks, which will function as a source of new ideas and approaches.

  3. Surfactant Assisted Hydrothermal Synthesis of CdSe Nanostructural Materials

    Institute of Scientific and Technical Information of China (English)

    Ganganagappa Nagaraju; Cujjarahalli Thimmanna Chandrappa

    2012-01-01

    CdSe/CTAB composite nanostructural materials were successfully synthesized at 160-200℃ for 2 days through a facile surfactant (cetyl trimethyl ammonium bromide-CTAB) assisted hydrothermal method us- ing cadmium acetate and sodium selenate as precursor. The obtained products were characterized by X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and thermo gravimetric analysis. Optical properties were studied by photoluminescence and UV-visible spectroscopy and morphology was investigated by scanning electron microscopy.

  4. Soft nanostructured films for directing the assembly of functional materials

    Science.gov (United States)

    Steer, D.; Kang, M.; Leal, C.

    2017-04-01

    Lipids are a class of biological small molecules with hydrophilic and hydrophobic constituents forming the structural membranes in cells. Over the past century an extensive understanding of lipid biology and biophysics has been developed illuminating lipids as an intricate, highly tunable, and hierarchical soft-matter system. In addition to serving as cell membrane models, lipids have been investigated as microphase separated structures in aqueous solutions. In terms of applications lipids have been realized as powerful structural motifs for the encapsulation and cellular delivery of genetic material. More recently, lipids have also revealed promise as thin film materials, exhibiting long-range periodic nano-scale order and tunable orientation. In this review we summarize the pertinent understanding of lipid nanostructure development in bulk aqueous systems followed by the current and potential perturbations to these results induced by introduction of a substrate. These effects are punctuated by a summary of our published results in the field of lipid thin films with added nucleic acids and key results introducing hard materials into lipid nanostructured substrates.

  5. Micro-/nanostructured multicomponent molecular materials: design, assembly, and functionality.

    Science.gov (United States)

    Yan, Dongpeng

    2015-03-23

    Molecule-based micro-/nanomaterials have attracted considerable attention because their properties can vary greatly from the corresponding macro-sized bulk systems. Recently, the construction of multicomponent molecular solids based on crystal engineering principles has emerged as a promising alternative way to develop micro-/nanomaterials. Unlike single-component materials, the resulting multicomponent systems offer the advantages of tunable composition, and adjustable molecular arrangement, and intermolecular interactions within their solid states. The study of these materials also supplies insight into how the crystal structure, molecular components, and micro-/nanoscale effects can influence the performance of molecular materials. In this review, we describe recent advances and current directions in the assembly and applications of crystalline multicomponent micro-/nanostructures. Firstly, the design strategies for multicomponent systems based on molecular recognition and crystal engineering principles are introduced. Attention is then focused on the methods of fabrication of low-dimensional multicomponent micro-/nanostructures. Their new applications are also outlined. Finally, we briefly discuss perspectives for the further development of these molecular crystalline micro-/nanomaterials.

  6. Stabilized super-thermite colloids: A new generation of advanced highly energetic materials

    Science.gov (United States)

    Elbasuney, Sherif; Gaber Zaky, M.; Radwan, Mostafa; Mostafa, Sherif F.

    2017-10-01

    One of the great impetus of nanotechnology on energetic materials is the achievement of nanothermites (metal-oxide/metal) which are characterized by massive heat output. Yet, full exploitation of super-thermites in highly energetic systems has not been achieved. This manuscript reports on the sustainable fabrication of colloidal Fe2O3 and CuO nanoparticles for thermite applications. TEM micrographs demonstrated mono-dispersed Fe2O3 and CuO with an average particle size of 3 and 15 nm respectively. XRD diffractograms demonstrated highly crystalline materials. SEM micrographs demonstrated a great tendency of the developed oxides to aggregate over drying process. The effective integration and dispersion of mono-dispersed colloidal thermite particles into energetic systems are vital for enhanced performance. Aluminum is of interest as highly energetic metal fuel. In this paper, synthesized Fe2O3 and CuO nanoparticles were re-dispersed in isopropyl alcohol (IPA) with aluminum nanoparticles using ultrasonic prope homogenizer. The colloidal thermite peraticles can be intgegrated into highly energetic system for subsequent nanocomposite development. Thanks to stabilization of colloidal CuO nanoparticles in IPA which could offer intimate mixing between oxidizer and metal fuel. The stabilization mechanism of CuO in IPA was correlated to steric stabilization with solvent molecules. This approach eliminated nanoparticle drying and the re-dispersion of dry aggregates into energetic materials. This manuscript shaded the light on the real development of colloidal thermite mixtures and their integration into highly energetic systems.

  7. Growth of Carbon Nanostructure Materials Using Laser Vaporization

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Lehozeky, S.

    2000-01-01

    Since the potential applications of carbon nanotubes (CNT) was discovered in many fields, such as non-structure electronics, lightweight composite structure, and drug delivery, CNT has been grown by many techniques in which high yield single wall CNT has been produced by physical processes including arc vaporization and laser vaporization. In this presentation, the growth mechanism of the carbon nanostructure materials by laser vaporization is to be discussed. Carbon nanoparticles and nanotubes have been synthesized using pulsed laser vaporization on Si substrates in various temperatures and pressures. Two kinds of targets were used to grow the nanostructure materials. One was a pure graphite target and the other one contained Ni and Co catalysts. The growth temperatures were 600-1000 C and the pressures varied from several torr to 500 torr. Carbon nanoparticles were observed when a graphite target was used, although catalysts were deposited on substrates before growing carbon films. When the target contains catalysts, carbon nanotubes (CNT) are obtained. The CNT were characterized by scanning electron microscopy, x-ray diffraction, optical absorption and transmission, and Raman spectroscopy. The temperature-and pressure-dependencies of carbon nanotubes' growth rate and size were investigated.

  8. Nanomanufacturing : nano-structured materials made layer-by-layer.

    Energy Technology Data Exchange (ETDEWEB)

    Cox, James V.; Cheng, Shengfeng; Grest, Gary Stephen; Tjiptowidjojo, Kristianto (University of New Mexico); Reedy, Earl David, Jr.; Fan, Hongyou; Schunk, Peter Randall; Chandross, Michael Evan; Roberts, Scott A.

    2011-10-01

    Large-scale, high-throughput production of nano-structured materials (i.e. nanomanufacturing) is a strategic area in manufacturing, with markets projected to exceed $1T by 2015. Nanomanufacturing is still in its infancy; process/product developments are costly and only touch on potential opportunities enabled by growing nanoscience discoveries. The greatest promise for high-volume manufacturing lies in age-old coating and imprinting operations. For materials with tailored nm-scale structure, imprinting/embossing must be achieved at high speeds (roll-to-roll) and/or over large areas (batch operation) with feature sizes less than 100 nm. Dispersion coatings with nanoparticles can also tailor structure through self- or directed-assembly. Layering films structured with these processes have tremendous potential for efficient manufacturing of microelectronics, photovoltaics and other topical nano-structured devices. This project is designed to perform the requisite R and D to bring Sandia's technology base in computational mechanics to bear on this scale-up problem. Project focus is enforced by addressing a promising imprinting process currently being commercialized.

  9. Novel hybrid nanostructured materials of magnetite nanoparticles and pectin

    Science.gov (United States)

    Sahu, Saurabh; Dutta, Raj Kumar

    2011-04-01

    A novel hybrid nanostructured material comprising superparamagnetic magnetite nanoparticles (MNPs) and pectin was synthesized by crosslinking with Ca2+ ions to form spherical calcium pectinate nanostructures, referred as MCPs, which were typically found to be 100-150 nm in size in dried condition, confirmed from transmission electron microscopy and scanning electron microscopy. The uniform size distribution was revealed from dynamic light scattering measurement. In aqueous medium the MCPs showed swelling behavior with an average size of 400 nm. A mechanism of formation of spherical MCPs is outlined constituting a MNP-pectin interface encapsulated by calcium pectinate at the periphery, by using an array of characterization techniques like zeta potential, thermogravimetry, Fourier transformed infrared and X-ray photoelectron spectroscopy. The MCPs were stable in simulated gastrointestinal fluid and ensured minimal loss of magnetic material. They exhibited superparamagnetic behavior, confirmed from zero field cooled and field cooled profiles and showed high saturation magnetization (Ms) of 46.21 emu/g at 2.5 T and 300 K. Ms decreased with increasing precursor pectin concentrations, attributed to quenching of magnetic moments by formation of a magnetic dead layer on the MNPs.

  10. Thermal Characterization of Nanostructures and Advanced Engineered Materials

    Science.gov (United States)

    Goyal, Vivek Kumar

    Continuous downscaling of Si complementary metal-oxide semiconductor (CMOS) technology and progress in high-power electronics demand more efficient heat removal techniques to handle the increasing power density and rising temperature of hot spots. For this reason, it is important to investigate thermal properties of materials at nanometer scale and identify materials with the extremely large or extremely low thermal conductivity for applications as heat spreaders or heat insulators in the next generation of integrated circuits. The thin films used in microelectronic and photonic devices need to have high thermal conductivity in order to transfer the dissipated power to heat sinks more effectively. On the other hand, thermoelectric devices call for materials or structures with low thermal conductivity because the performance of thermoelectric devices is determined by the figure of merit Z=S2sigma/K, where S is the Seebeck coefficient, K and sigma are the thermal and electrical conductivity, respectively. Nanostructured superlattices can have drastically reduced thermal conductivity as compared to their bulk counterparts making them promising candidates for high-efficiency thermoelectric materials. Other applications calling for thin films with low thermal conductivity value are high-temperature coatings for engines. Thus, materials with both high thermal conductivity and low thermal conductivity are technologically important. The increasing temperature of the hot spots in state-of-the-art chips stimulates the search for innovative methods for heat removal. One promising approach is to incorporate materials, which have high thermal conductivity into the chip design. Two suitable candidates for such applications are diamond and graphene. Another approach is to integrate the high-efficiency thermoelectric elements for on-spot cooling. In addition, there is strong motivation for improved thermal interface materials (TIMs) for heat transfer from the heat-generating chip

  11. Nanostructured powders and their industrial application. Materials Research Society symposium proceedings Volume 520

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, G.; Mark, J.E.; Burns, G.T.; Hua, D.W. [eds.

    1998-07-01

    This new volume from the MRS brings together industrial and academic researchers involved in the synthesis and use of nanostructured powders such as fumed silica, pyrolytic titania and precipitated silica, as well as less conventional nanostructured powders such as exfoliated clays. Similarities and differences among these various fields of study and application are featured. In some ways, the volume is a continuation of the ``Better Ceramics Through Chemistry'' series. One main difference, however, is that this volume focused on the industrial use of these materials. Topics include: overview of nanopowder technology; physical aspects of nanostructured powders; synthesis of nanostructured powders; and applications of nanostructured powders.

  12. Quantum materials. Lateral semiconductor nanostructures, hybrid systems and nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Heitmann, Detlef (ed.) [Hamburg Univ. (Germany). Inst. fuer Angewandte Physik

    2010-07-01

    Semiconductor nanostructures are ideal systems to tailor the physical properties via quantum effects, utilizing special growth techniques, self-assembling, wet chemical processes or lithographic tools in combination with tuneable external electric and magnetic fields. Such systems are called ''Quantum Materials''.The electronic, photonic, and phononic properties of these systems are governed by size quantization and discrete energy levels. The charging is controlled by the Coulomb blockade. The spin can be manipulated by the geometrical structure, external gates and by integrating hybrid ferromagnetic emitters.This book reviews sophisticated preparation methods for quantum materials based on III-V and II-VI semiconductors and a wide variety of experimental techniques for the investigation of these interesting systems. It highlights selected experiments and theoretical concepts and gives such a state-of-the-art overview about the wide field of physics and chemistry that can be studied in these systems. (orig.)

  13. Stab Sensitivity of Energetic Nanolaminates

    Energy Technology Data Exchange (ETDEWEB)

    Gash, A; Barbee, T; Cervantes, O

    2006-05-22

    This work details the stab ignition, small-scale safety, and energy release characteristics of bimetallic Al/Ni(V) and Al/Monel energetic nanolaminate freestanding thin films. The influence of the engineered nanostructural features of the energetic multilayers is correlated with both stab initiation and small-scale energetic materials testing results. Structural parameters of the energetic thin films found to be important include the bi-layer period, total thickness of the film, and presence or absence of aluminum coating layers. In general the most sensitive nanolaminates were those that were relatively thick, possessed fine bi-layer periods, and were not coated. Energetic nanolaminates were tested for their stab sensitivity as freestanding continuous parts and as coarse powders. The stab sensitivity of mock M55 detonators loaded with energetic nanolaminate was found to depend strongly upon both the particle size of the material and the configuration of nanolaminate material, in the detonator cup. In these instances stab ignition was observed with input energies as low as 5 mJ for a coarse powder with an average particle dimension of 400 {micro}m. Selected experiments indicate that the reacting nanolaminate can be used to ignite other energetic materials such as sol-gel nanostructured thermite, and conventional thermite that was either coated onto the multilayer substrate or pressed on it. These results demonstrate that energetic nanolaminates can be tuned to have precise and controlled ignition thresholds and can initiate other energetic materials and therefore are viable candidates as lead-free impact initiated igniters or detonators.

  14. Synthesis, Characterization, and Multimillion-Atom Simulation of Halogen-Based Energetic Materials for Agent Defeat

    Science.gov (United States)

    2013-04-01

    Kolesnikov NIST: Liu New Discoveries, Inventions, or Patent Disclosures K. O. Christe and G. Drake, “Energetic Ionic Liquids ,” US Patent 7,771,549, Aug...DTRA-TR-13-23 Synthesis, Characterization, and Multimillion-Atom Simulation of Halogen -Based Energetic Materials for Agent Defeat Approved for...second foot foot-pound-force gallon (U.S. liquid ) inch jerk joule/kilogram (J/kg) radiation dose absorbed kilotons kip (1000 lbf) kip/inch 2

  15. Irradiation Induced Microstructure Evolution in Nanostructured Materials: A Review.

    Science.gov (United States)

    Liu, Wenbo; Ji, Yanzhou; Tan, Pengkang; Zang, Hang; He, Chaohui; Yun, Di; Zhang, Chi; Yang, Zhigang

    2016-02-06

    Nanostructured (NS) materials may have different irradiation resistance from their coarse-grained (CG) counterparts. In this review, we focus on the effect of grain boundaries (GBs)/interfaces on irradiation induced microstructure evolution and the irradiation tolerance of NS materials under irradiation. The features of void denuded zones (VDZs) and the unusual behavior of void formation near GBs/interfaces in metals due to the interactions between GBs/interfaces and irradiation-produced point defects are systematically reviewed. Some experimental results and calculation results show that NS materials have enhanced irradiation resistance, due to their extremely small grain sizes and large volume fractions of GBs/interfaces, which could absorb and annihilate the mobile defects produced during irradiation. However, there is also literature reporting reduced irradiation resistance or even amorphization of NS materials at a lower irradiation dose compared with their bulk counterparts, since the GBs are also characterized by excess energy (compared to that of single crystal materials) which could provide a shift in the total free energy that will lead to the amorphization process. The competition of these two effects leads to the different irradiation tolerance of NS materials. The irradiation-induced grain growth is dominated by irradiation temperature, dose, ion flux, character of GBs/interface and nanoprecipitates, although the decrease of grain sizes under irradiation is also observed in some experiments.

  16. Near-Resonant Thermomechanics of Energetic and Mock Energetic Composite Materials

    Science.gov (United States)

    2016-11-01

    the inelastic behavior of many materials like metals [12,13], concrete [14], soils [15], metal matrix composites [16], filled rubber [17], Asphalt...endochronic constitutive equations in 3D. The scheme has been modified to include rate-dependent (viscoplastic) effects. In addition, an efficient...histories. Strength of Materials. 1993. 25(5): p. 315–322. 14. Z. P. Bazant and P. D. Bath. Endochronic theory of inelasticity and failure of concrete

  17. EPR and magnetism of the nanostructured natural carbonaceous material shungite

    Science.gov (United States)

    Augustyniak-Jabłokow, Maria Aldona; Yablokov, Yurii V.; Andrzejewski, Bartłomiej; Kempiński, Wojciech; Łoś, Szymon; Tadyszak, Krzysztof; Yablokov, Mikhail Y.; Zhikharev, Valentin A.

    2010-04-01

    The X-band EPR and magnetic susceptibility in the temperature range 4.2-300 K study of the shungite-I, natural nanostructured material from the deposit of Shunga are reported. Obtained results allow us to assign the EPR signal to conduction electrons, estimate their number, N P, and evaluate the Pauli paramagnetism contribution to shungite susceptibility. A small occupation (~5%) of the localized nonbonding π states in the zigzag edges of the open-ended graphene-like layers and/or on σ ( sp 2+ x ) orbitals in the curved parts of the shungite globules has been also revealed. The observed temperature dependence of the EPR linewidth can be explained by the earlier considered interaction of conduction π electrons with local phonon modes associated with the vibration of peripheral carbon atoms of the open zigzag-type edges and with peripheral carbon atoms cross-linking different nanostructures. The relaxation time T 2 and diffusion time T D are found to have comparable values (2.84 × 10-8 and 1.73 × 10-8 s at 5.2 K, respectively), and similar dependence on temperature. The magnetic measurements have revealed the suppression of orbital diamagnetism due to small amount of large enough fragments of the graphene layers.

  18. Water-evaporation-induced electricity with nanostructured carbon materials.

    Science.gov (United States)

    Xue, Guobin; Xu, Ying; Ding, Tianpeng; Li, Jia; Yin, Jun; Fei, Wenwen; Cao, Yuanzhi; Yu, Jin; Yuan, Longyan; Gong, Li; Chen, Jian; Deng, Shaozhi; Zhou, Jun; Guo, Wanlin

    2017-01-30

    Water evaporation is a ubiquitous natural process that harvests thermal energy from the ambient environment. It has previously been utilized in a number of applications including the synthesis of nanostructures and the creation of energy-harvesting devices. Here, we show that water evaporation from the surface of a variety of nanostructured carbon materials can be used to generate electricity. We find that evaporation from centimetre-sized carbon black sheets can reliably generate sustained voltages of up to 1 V under ambient conditions. The interaction between the water molecules and the carbon layers and moreover evaporation-induced water flow within the porous carbon sheets are thought to be key to the voltage generation. This approach to electricity generation is related to the traditional streaming potential, which relies on driving ionic solutions through narrow gaps, and the recently reported method of moving ionic solutions across graphene surfaces, but as it exploits the natural process of evaporation and uses cheap carbon black it could offer advantages in the development of practical devices.

  19. Water-evaporation-induced electricity with nanostructured carbon materials

    Science.gov (United States)

    Xue, Guobin; Xu, Ying; Ding, Tianpeng; Li, Jia; Yin, Jun; Fei, Wenwen; Cao, Yuanzhi; Yu, Jin; Yuan, Longyan; Gong, Li; Chen, Jian; Deng, Shaozhi; Zhou, Jun; Guo, Wanlin

    2017-05-01

    Water evaporation is a ubiquitous natural process that harvests thermal energy from the ambient environment. It has previously been utilized in a number of applications including the synthesis of nanostructures and the creation of energy-harvesting devices. Here, we show that water evaporation from the surface of a variety of nanostructured carbon materials can be used to generate electricity. We find that evaporation from centimetre-sized carbon black sheets can reliably generate sustained voltages of up to 1 V under ambient conditions. The interaction between the water molecules and the carbon layers and moreover evaporation-induced water flow within the porous carbon sheets are thought to be key to the voltage generation. This approach to electricity generation is related to the traditional streaming potential, which relies on driving ionic solutions through narrow gaps, and the recently reported method of moving ionic solutions across graphene surfaces, but as it exploits the natural process of evaporation and uses cheap carbon black it could offer advantages in the development of practical devices.

  20. Advanced nanostructured materials for energy storage and conversion

    Science.gov (United States)

    Hutchings, Gregory S.

    Due to a global effort to reduce greenhouse gas emissions and to utilize renewable sources of energy, much effort has been directed towards creating new alternatives to fossil fuels. Identifying novel materials for energy storage and conversion can enable radical changes to the current fuel production infrastructure and energy utilization. The use of engineered nanostructured materials in these systems unlocks unique catalytic activity in practical configurations. In this work, research efforts have been focused on the development of nanostructured materials to address the need for both better energy conversion and storage, with applications toward Li-O2 battery electrocatalysts, electrocatalytic generation of H2, conversion of furfural to useful chemicals and fuels, and Li battery anode materials. Highly-active alpha-MnO2 materials were synthesized for use as bifunctional oxygen reduction (ORR) and evolution (OER) catalysts in Li-O2 batteries, and were evaluated under operating conditions with a novel in situ X-ray absorption spectroscopy configuration. Through detailed analysis of local coordination and oxidation states of Mn atoms at key points in the electrochemical cycle, a self-switching behavior affecting the bifunctional activity was identified and found to be critical. In an additional study of materials for lithium batteries, nanostructured TiO2 anode materials doped with first-row transition metals were synthesized and evaluated for improving battery discharge capacity and rate performance, with Ni and Co doping at low levels found to cause the greatest enhancement. In addition to battery technology research, I have also sought to find inexpensive and earth-abundant electrocatalysts to replace state-of-the-art Pt/C in the hydrogen evolution reaction (HER), a systematic computational study of Cu-based bimetallic electrocatalysts was performed. During the screening of dilute surface alloys of Cu mixed with other first-row transition metals, materials with

  1. Pentazadiene: a high-nitrogen linkage in energetic materials.

    Science.gov (United States)

    Wang, Qi; Pang, Fuqing; Wang, Guilong; Huang, Jinglun; Nie, Fude; Chen, Fu-Xue

    2017-02-16

    A novel N5-linear energetic moiety of pentazadiene has been constructed for the first time from a triazene precursor. Thus, a series of 1,3,5-tri(tetrazol-5-yl)pentaza-1,4-dienes have been synthesized in moderate to high yields by treatment of 1,3-bis(tetr-azol-5-yl)triazenes with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) under mild conditions. All compounds were fully characterized using IR spectroscopy, (1)H and (13)C NMR spectroscopy, HRMS, and differential scanning calorimetry (DSC), and, in the case of 1,3,5-tri(2-methyltetrazol-5-yl)pentaza-1,4-diene (2a) together with single crystal X-ray structuring and (15)N NMR spectroscopy. Calculations predict that 2a has a heat of formation of 1699.2 kJ mol(-1).

  2. Compatibility testing of energetic materials at TNO-PML and MIAT

    NARCIS (Netherlands)

    Krabbendam-La Haye, E.L.M.; Klerk, W.P.C. de; Miszczak, M.; Szymanowski, J.

    2003-01-01

    Compatibility is an important property for energetic materials and their additives such as a casing material or a binder. If these substances are incompatible an extra risk is introduced in handling and storage of ammunition and explosives. As part of a co-operation program between the Dutch TNO-PML

  3. On the decomposition mechanisms of new imidazole-based energetic materials.

    Science.gov (United States)

    Yu, Zijun; Bernstein, Elliot R

    2013-02-28

    New imidazole-based energetic molecules (1,4-dinitroimidazole, 2,4-dinitroimidazole, 1-methyl-2,4-dinitroimidazole, and 1-methyl-2,4,5-trinitroimidazole) are studied both experimentally and theoretically. The NO molecule is observed as a main decomposition product from the above nitroimidazole energetic molecules excited at three UV wavelengths (226, 236, and 248 nm). Resolved rotational spectra related to three vibronic bands (0-0), (0-1), and (0-2) of the NO (A (2)Σ(+) ← X (2)Π) electronic transition have been obtained. A unique excitation wavelength independent dissociation channel is characterized for these four nitroimidazole energetic molecules: this pathway generates the NO product with a rotationally cold (10-60 K) and vibrationally hot (1300-1600 K) internal energy distribution. The predicted reaction mechanism for the nitroimidazole energetic molecule decomposition subsequent to electronic excitation is the following: electronically excited nitroimidazole energetic molecules descend to their ground electronic states through a series of conical intersections, dissociate on their ground electronic states subsequent to a nitro-nitrite isomerization, and produce NO molecules. Different from PETN, HMX, and RDX, the thermal dissociation process (ground electronic state decomposition from the Franck-Condon equilibrium point) of multinitroimidazoles is predicted to be a competition between NO(2) elimination and nitro-nitrite isomerization followed by NO elimination for all multinitroimidazoles except 1,4-dinitroimidazole. In this latter instance, N-NO(2) homolysisis becomes the dominant decomposition channel on the ground electronic state, as found for HMX and RDX. Comparison of the stability of nitro-containing energetic materials with R-NO(2) (R = C, N, O) moieties is also discussed. Energetic materials with C-NO(2) are usually more thermally stable and impact/shock insensitive than are other energetic materials with N-NO(2) and O-NO(2) moieties. The

  4. Multifunctional, flexible electronic systems based on engineered nanostructured materials.

    Science.gov (United States)

    Ko, Hyunhyub; Kapadia, Rehan; Takei, Kuniharu; Takahashi, Toshitake; Zhang, Xiaobo; Javey, Ali

    2012-08-31

    The development of flexible electronic systems has been extensively researched in recent years, with the goal of expanding the potential scope and market of modern electronic devices in the areas of computation, communications, displays, sensing and energy. Uniquely, the use of soft polymeric substrates enables the incorporation of advanced features beyond mechanical bendability and stretchability. In this paper, we describe several functionalities which can be achieved using engineered nanostructured materials. In particular, reversible binding, self-cleaning, antireflective and shape-reconfigurable properties are introduced for the realization of multifunctional, flexible electronic devices. Examples of flexible systems capable of spatial mapping and/or responding to external stimuli are also presented as a new class of user-interactive devices.

  5. SIMULATION OF SYNTHESIS OF CLUSTER-ASSEMBLED NANOSTRUCTURED MATERIALS

    Directory of Open Access Journals (Sweden)

    M.S.Byshkin

    2003-01-01

    Full Text Available A model is described to simulate the formation of nanostructured materials by cluster beam deposition. Clusters are modelled by spherical balls with a given size distribution function, which fall to the substrate and stick to the growing structure. The mobility of clusters along the film surface is modelled by introduction of a critical angle at which a falling ball meets a ball that belongs to the structure. When the falling ball touches one of the balls in the structure at an angle smaller than the critical one, it sticks to the film; otherwise the ball rolls along the surface till it meets other balls. It is shown that a variety of structures similar to those observed experimentally can be produced. The density of the model structures, percolation thresholds and the surface roughness are analyzed.

  6. Nanostructured lithium sulfide materials for lithium-sulfur batteries

    Science.gov (United States)

    Lee, Sang-Kyu; Lee, Yun Jung; Sun, Yang-Kook

    2016-08-01

    Upon the maturation and saturation of Li-ion battery technologies, the demand for the development of energy storage systems with higher energy densities has surged to meet the needs of key markets such as electric vehicles. Among the many next generation high-energy storage options, the Lisbnd S battery system is considered particularly close to mass commercialization because of its low cost and the natural abundance of sulfur. In this review, we focus on nanostructured Li2S materials for Lisbnd S batteries. Due to a lithium source in its molecular structure, Li2S can be coupled with various Li-free anode materials, thereby giving it the potential to surmount many of the problems related with a Li-metal anode. The hurdles that impede the full utilization of Li2S materials include its high activation barrier and the low electrical conductivity of bulk Li2S particles. Various strategies that can be used to assist the activation process and facilitate electrical transport are analyzed. To provide insight into the opportunities specific to Li2S materials, we highlight some major advances and results that have been achieved in the development of metal Li-free full cells and all-solid-state cells based on Li2S cathodes.

  7. Azole energetic materials: initial mechanisms for the energy release from electronical excited nitropyrazoles.

    Science.gov (United States)

    Yuan, Bing; Yu, Zijun; Bernstein, Elliot R

    2014-01-21

    Decomposition of energetic material 3,4-dinitropyrazole (DNP) and two model molecules 4-nitropyrazole and 1-nitropyrazole is investigated both theoretically and experimentally. The initial decomposition mechanisms for these three nitropyrazoles are explored with complete active space self-consistent field (CASSCF) level. The NO molecule is observed as an initial decomposition product from all three materials subsequent to UV excitation. Observed NO products are rotationally cold (energetic material DNP, NO is produced on the ground state surface, as the S1 decomposition pathway is energetically unavailable. The theoretically predicted mechanism is consistent with the experimental results, as DNP decomposes in a lower electronic state than do the model systems and thus the vibrational energy in the NO product from DNP should be hotter than from the model systems. The observed rotational energy distributions for NO are consistent with the final structures of the respective transition states for each molecule.

  8. Preparation and properties on hollow nano-structured smoke material

    Science.gov (United States)

    Liu, Xiang-cui; Dai, Meng-yan; Fang, Guo-feng; Shi, Wei-dong; Cheng, Xiang; Liu, Hai-feng; Zhang, Tong

    2013-09-01

    In recent years, the weapon systems of laser guidance and infrared (IR) imaging guidance have been widely used in modern warfare because of their high precision and strong anti-interference. Notwithstanding, military smoke, as a rapid and effective passive jamming means, can effectively counteract the attack of enemy precision-guided weapons by scattering and absorbability. Conventional smoke has good attenuation capability only to visible light (0.4-0.76 μm), but hardly any effect to other electromagnetic wave band. The weapon systems of laser guidance and IR imaging guidance usually work in broad band, including near IR (1-3 μm), middle IR (3-5 μm), far IR (8-14 μm), and so on. Accordingly, exploiting and using new efficient obscurant materials, which is one of the important factors that develop smoke technology, have become a focus and attracted more interests around the world. Then nano-structured materials that are developing very quickly have turned into our new choice. Hollow nano-structured materials (HNSM) have many special properties because of their nano-size wall-thickness and sub-micron grain-size. After a lot of HNSM were synthesized in this paper, their physical and chemical properties, including grain size, phase composition, microstructure, optical properties and resistivity were tested and analysed. Then the experimental results of the optical properties showed that HNSM exhibit excellent wave-absorbing ability in ultraviolet, visible and infrared regions. On the basis of the physicochemmical properties, HNSM are firstly applied in smoke technology field. And the obscuration performance of HNSM smoke was tested in smoke chamber. The testing waveband included 1.06μm and 10.6μm laser, 3-5μm and 8-14μm IR radiation. Then the main parameters were obtained, including the attenuation rate, the transmission rate, the mass extinction coefficient, the efficiency obscuring time, and the sedimentation rate, etc. The main parameters of HNSM smoke were

  9. Combustion aspects of the reapplication of energetic materials as fuels as a viable demil technology

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.; Davis, K.; Sinquefield, S.; Huey, S.; Lipkin, J.; Shah, D.; Ross, J.; Sclippa, G. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility

    1996-05-01

    This investigation addresses the combustion-related aspects of the reapplication of energetic materials as fuels in boilers as an economically viable and environmentally acceptable use of excess energetic materials. The economics of this approach indicate that the revenues from power generation and chemical recovery approximately equal the costs of boiler modification and changes in operation. The primary tradeoff is the cost of desensitizing the fuels against the cost of open burn/open detonation (OB/OD) or other disposal techniques. Two principal combustion-related obstacles to the use of energetic-material-derived fuels are NO{sub x} generation and the behavior of metals. NO{sub x} measurements obtained in this investigation indicate that the nitrated components (nitrocellulose, nitroglycerin, etc.) of energetic materials decompose with NO{sub x} as the primary product. This can lead to high uncontrolled NO{sub x} levels (as high as 2,600 ppm on a 3% O{sub 2} basis for a 5% blend of energetic material in the fuel). NO{sub x} levels are sensitive to local stoichiometry and temperature. The observed trends resemble those common during the combustion of other nitrogen-containing fuels. Implications for NO{sub x} control strategies are discussed. The behavior of inorganic components in energetic materials tested in this investigation could lead to boiler maintenance problems such as deposition, grate failure, and bed agglomeration. The root cause of the problem is the potentially extreme temperature generated during metal combustion. Implications for furnace selection and operation are discussed.

  10. Theoretical Studies of Small-System Thermodynamics in Energetic Materials

    Science.gov (United States)

    2016-01-06

    3D hard - sphere and Lennard-Jones fluids for which the surroundings are modelled as reflecting hard walls that confine the system along one direction...Molecular Materials under Static and Dynamic Compression " 2013 Fall ACS COMP Symposium: "Chemical Mechanisms in Advanced Materials" in the Materials...Jiang: 19th Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter (SCCM-2015) Tampa, Florida, 2015; “Molecular

  11. An evaluation of complementary approaches to elucidate fundamental interfacial phenomena driving adhesion of energetic materials.

    Science.gov (United States)

    Hoss, Darby J; Knepper, Robert; Hotchkiss, Peter J; Tappan, Alexander S; Boudouris, Bryan W; Beaudoin, Stephen P

    2016-07-01

    Cohesive Hamaker constants of solid materials are measured via optical and dielectric properties (i.e., Lifshitz theory), inverse gas chromatography (IGC), and contact angle measurements. To date, however, a comparison across these measurement techniques for common energetic materials has not been reported. This has been due to the inability of the community to produce samples of energetic materials that are readily compatible with contact angle measurements. Here we overcome this limitation by using physical vapor deposition to produce thin films of five common energetic materials, and the contact angle measurement approach is applied to estimate the cohesive Hamaker constants and surface energy components of the materials. The cohesive Hamaker constants range from 85zJ to 135zJ across the different films. When these Hamaker constants are compared to prior work using Lifshitz theory and nonpolar probe IGC, the relative magnitudes can be ordered as follows: contact angle>Lifshitz>IGC. Furthermore, the dispersive surface energy components estimated here are in good agreement with those estimated by IGC. Due to these results, researchers and technologists will now have access to a comprehensive database of adhesion constants which describe the behavior of these energetic materials over a range of settings. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Computational studies on energetic properties of nitrogen-rich energetic materials with ditetrazoles

    Indian Academy of Sciences (India)

    Li Xiao-Hong; Zhang Rui-Zhou

    2014-11-01

    Based on the full optimized molecular geometric structures at B3LYP/6-311++G**level, the densities (), heats of formation (HOFs), detonation velocities (D) and pressures (P) for a series of ditetrazoles derivatives, were investigated to look for high energy density materials (HEDMs). The results show that the influence of different substituted groups on HOFs has the order of -N3>-CN>-NH2>-NO2>-NF2>-ONO2>-H>-CH3>-CF3. The introduction of -CF3 groups is more favourable for increasing the density and the introduction of -CH3 groups is not favourable for increasing the density. In addition, all the series combined with -NF2 group except B-NF2 all have higher densities, larger D and P. F-NF2 may be regarded as the potential candidates of HEDMs because of the largest detonation velocity and pressure among these derivatives.The energy gaps between the HOMO and LUMO of the studied compounds are also investigated.

  13. Computational studies on 1,2,4-Triazolium-based salts as energetic materials

    Indian Academy of Sciences (India)

    Rakhi Singh; Hari Ji Singh; S K Sengupta

    2015-06-01

    The results of the computational studies performed on 1,2,4-triazolium cation-based salts designed by pairing it with energetic nitro-substituted 5- membered N-heterocyclic anions such as 5-nitrotetrazolate, 3,5-dinitrotriazolate, and 2,4,5 trinitroimidazolate are reported. Condensed phase heats of formation of the designed ionic salts and their thermodynamic and energetic properties have also been calculated. The results show that these salts are potential energetic materials and possess high positive heats of formation. The detonation velocity, D, and detonation pressure, P, have been calculated using the Kamlet-Jacobs equation and found to be 7–8 km/s and 25–29 GPa, respectively. These values fall in the range of the criteria to designate them as high-energy-density materials. Nucleus independent chemical shift (NICS) studies performed on the designed molecules show that these salts are stable in nature.

  14. Hydrogen Transfer in Energetic Materials from ReaxFF and DFT Calculations.

    Science.gov (United States)

    Sergeev, Oleg V; Yanilkin, Alexey V

    2017-04-27

    Energetic materials are characterized by fast and complex chemical reactions. It makes them hardly available for kinetic experiments in relevant conditions and a good target for reactive molecular dynamics simulations. In this work, unimolecular and condensed-phase thermal decomposition of pentaerythritol tetranitrate (PETN) are investigated by ReaxFF molecular dynamics. It is shown that the decomposition kinetics in condensed phase may be described with the activation barrier lower by a factor of 2 than that for isolated molecules. The effect of the intermolecular hydrogen transfer is revealed in condensed phase. Energetic barriers for hydrogen transfer in two energetic materials (methyl nitrate, which is a nitroester as well as PETN, and o-nitrotoluene) are studied with ReaxFF and DFT using nudged elastic band technique. The results indicate that ReaxFF gives significantly lower activation energy for intermolecular hydrogen transfer in nitroesters than different DFT approximations, which explains the molecular dynamics results for PETN.

  15. Thermal Energetic Reactor with High Reproduction of Fission Materials

    Directory of Open Access Journals (Sweden)

    Vladimir M. Kotov

    2012-01-01

    On the base of thermal reactors with high fission materials reproduction world atomic power engineering development supplying higher power and requiring smaller speed of raw uranium mining, than in the variant with fast reactors, is possible.

  16. Nanostructured materials with biomimetic recognition abilities for chemical sensing

    Science.gov (United States)

    Bajwa, Sadia Zafar; Mustafa, Ghulam; Samardzic, Renata; Wangchareansak, Thipvaree; Lieberzeit, Peter A.

    2012-06-01

    Binding features found in biological systems can be implemented into man-made materials to design nanostructured artificial receptor matrices which are suitable, e.g., for chemical sensing applications. A range of different non-covalent interactions can be utilized based on the chemical properties of the respective analyte. One example is the formation of coordinative bonds between a polymerizable ligand (e.g., N-vinyl-2-pyrrolidone) and a metal ion (e.g., Cu(II)). Optimized molecularly imprinted sensor layers lead to selectivity factors of at least 2 compared to other bivalent ions. In the same way, H-bonds can be utilized for such sensing purposes, as shown in the case of Escherichia coli. The respective molecularly imprinted polymer leads to the selectivity factor of more than 5 between the W and B strains, respectively. Furthermore, nanoparticles with optimized Pearson hardness allow for designing sensors to detect organic thiols in air. The `harder' MoS2 yields only about 40% of the signals towards octane thiol as compared to the `softer' Cu2S. However, both materials strongly prefer molecules with -SH functionality over others, such as hydrocarbon chains. Finally, selectivity studies with wheat germ agglutinin (WGA) reveal that artificial receptors yield selectivities between WGA and bovine serum albumin that are only about a factor of 2 which is smaller than natural ligands.

  17. Studies on compatibility of energetic materials by thermal methods

    Directory of Open Access Journals (Sweden)

    Maria Alice Carvalho Mazzeu

    2010-04-01

    Full Text Available The chemical compatibility of explosives, pyrotechnics and propellants with those materials is studied to evaluate potential hazards when in contact with other materials during production, storage and handling. Compatibility can be studied by several thermal methods as DSC (differential scanning calorimetry, TG (Thermogravimetry, VST (Vacuum stability test and others. The test methods and well defined criteria are the most important elements when a compatibility study is being accomplished. In this paper, the compatibility of two very important high explosives used in ammunition, RDX (Cyclo-1,3,5-trimethylene-2,4,6-trinitramine and HMX (Cyclotetramethylene tetranitramine was studied with the materials: fluoroelastomer (Viton and powdered aluminum (Al, using DSC and VST methods. The criteria to judge the compatibility between materials is based on a standardization agreement (STANAG 4147, 2001, and the final conclusion is that explosives and this materials are compatible, but in DSC it was observed that the peak of decomposition temperature of the admixture of RDX with Al decreased in 3º C and another peak appeared after the decomposition peak.

  18. Development of Methods for Surface Modification of Nanostructured Materials

    Science.gov (United States)

    Marsh, David A.

    The surfaces of a material become increasingly more influential when the dimensions are reduced, because a larger percentage of the atoms are exposed on the surface. The surface environment of nanostructured materials dictates both physical properties and function, but is synthetically challenging to control. Although the desired functionality is commonly introduced via post-synthetic modification, it would be advantageous to minimize the number of synthetic steps by having specific function installed in the precursor. This work describes efforts to investigate new precursor complexes for the synthesis of nanoparticles, in addition to electrochemical studies on single monolayer films for electrocatalysis. Chapter 2 focuses on the preparation of magnetic nanoaparticles, and the synthesis of a polymerizable surfactant, stacac, to be used to generate composite materials. Although an iron complex of stacac could be used as a precursor for magnetic nanoparticles, favorable composite materials could only be produced by introduction of stacac after isolation of magnetic nanoparticles. Chapter 3 describes the synthesis of Au(I) complexes with various thiourea-based ligands, to be used as precursors for gold nanoparticles. The experimental conditions were varied and parameters were found where addition of a reducing agent generated solution-stable gold nanoparticles in a reproducible manner. It was determined that only aggregated gold nanoparticles were produced when Au(I) complexes were generated in situ and the use of crystalline precursors resulted in soluble gold nanoparticles. Chapter 4 discusses the preparation of electrocatalysts for the oxidation of water with a focus on accurately determining the active surface area. A monolayer of cobalt was prepared on a gold electrode by underpotential deposition and used as an electrocatalyst for water oxidation. Because the surface area of gold can be measured directly, deposition of a single monolayer produced negligible

  19. Some aspects of applying nanostructured materials in air filtration, water filtration and electrical engineering

    Science.gov (United States)

    Kimmer, Dusan; Vincent, Ivo; Lovecka, Lenka; Kazda, Tomas; Giurg, Adam; Skorvan, Ondrej

    2017-05-01

    Nanostructures prepared from nanofibres and nanostructured composites prepared from nanofibres and fillers are gradually becoming increasingly demanded materials for applications in various industrial branches connected with catalysis, environment protection (air filtration, waste water treatment, sound absorption), in biological engineering, electronics (battery separators, electrode materials), etc. Selected applications of these materials prepared in the company SPUR a.s. are summed up in the following presentation.

  20. Encapsulation of energetic materials by cooling and electrospray crystallization

    NARCIS (Netherlands)

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der

    2012-01-01

    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  1. Encapsulation of energetic materials by cooling and electrospray crystallization

    NARCIS (Netherlands)

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der

    2012-01-01

    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  2. Chemical conversion of energetic materials to higher value products

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A.R.; Sanner, R.D.; Pagoria, P.F.

    1996-05-01

    The objective of this program is to develop novel, innovative solutions for the disposal of surplus explosives resulting from the demilitarization of nuclear and conventional munitions. Studies related to the conversion of TNT and Explosive D to potentially useful materials are described.

  3. Self-Channeling of Femtosecond Laser Pulses for Rapid and Efficient Standoff Detection of Energetic Materials

    Science.gov (United States)

    2009-01-01

    Laser Pulses for Rapid and Efficient Standoff Detection of Energetic Materials Matthieu Baudelet, Martin Richardson, Townes laser Institute, CREOL...2007 [3] D.A. Cremers and L.J. Radziemski, Handbook of laser-induced breakdown spectroscopy, Wiley, 2006 [4] A.W. Miziolek, V. Palleschi and I

  4. High-Energy-Density LCA-Coupled Structural Energetic Materials for Counter WMD Applications

    Science.gov (United States)

    2014-04-01

    morphology , etc.) of reactants. In the case of the equivolumetric Ta+Fe2O3 powder mixtures, pre-densification results in generating Fe2O3 as the more...published in the following papers. • N.N. Thadhani and J.K. Cochran, "Energetic Materials", DTRA Basic and Applied Research Program Newsletter , V2, N3, p

  5. Growth and energetics in Spisula subtruncata (Da Costa) and the effect of suspended bottom material

    DEFF Research Database (Denmark)

    Møhlenberg, F.; Kiørboe, Thomas

    1981-01-01

    The influence of suspended bottom material (0-25 mg/l) and algal cells (Phaeodactylum tricornutum) (0-500 .mu.g dry org wt[organic weight]/l) on clearance, growth and energetics in S. subtruncata (da Costa) was studied. Clearance and respiration rate were independent of concentrations of algae...

  6. Single-Molecule Investigations of Morphology and Mass Transport Dynamics in Nanostructured Materials

    Science.gov (United States)

    Higgins, Daniel A.; Park, Seok Chan; Tran-Ba, Khanh-Hoa; Ito, Takashi

    2015-07-01

    Nanostructured materials such as mesoporous metal oxides and phase-separated block copolymers form the basis for new monolith, membrane, and thin film technologies having applications in energy storage, chemical catalysis, and separations. Mass transport plays an integral role in governing the application-specific performance characteristics of many such materials. The majority of methods employed in their characterization provide only ensemble data, often masking the nanoscale, molecular-level details of materials morphology and mass transport. Single-molecule fluorescence methods offer direct routes to probing these characteristics on a single-molecule/single-nanostructure basis. This article provides a review of single-molecule studies focused on measurements of anisotropic diffusion, adsorption, partitioning, and confinement in nanostructured materials. Experimental methods covered include confocal and wide-field fluorescence microscopy. The results obtained promise to deepen our understanding of mass transport mechanisms in nanostructures, thus aiding in the realization of advanced materials systems.

  7. Spallation products induced by energetic neutrons in plastic detector material

    CERN Document Server

    Grabisch, K; Enge, W; Scherzer, R

    1977-01-01

    Cellulose nitrate plastic detector sheets were irradiated with secondary neutrons of the 22 GeV/c proton beam at the CERN accelerator. He, Li and Be particles which are produced in nuclear interactions of the neutrons with the target elements C, N and O of the plastic detector material are measured. Preliminary angle and range distributions and isotropic abundances of the secondary particles are discussed. (6 refs).

  8. DMSO/base hydrolysis method for the disposal of high explosives and related energetic materials

    Science.gov (United States)

    Desmare, Gabriel W.; Cates, Dillard M.

    2002-05-14

    High explosives and related energetic materials are treated via a DMSO/base hydrolysis method which renders them non-explosive and/or non-energetic. For example, high explosives such as 1,3,5,7-tetraaza-1,3,5,7-tetranitrocyclooctane (HMX), 1,3,5-triaza-1,3,5-trinitrocyclohexane (RDX), 2,4,6-trinitrotoluene (TNT), or mixtures thereof, may be dissolved in a polar, aprotic solvent and subsequently hydrolyzed by adding the explosive-containing solution to concentrated aqueous base. Major hydrolysis products typically include nitrite, formate, and nitrous oxide.

  9. N-Nitrosarcosine: An Economic Precursor for the Synthesis of New Energetic Materials.

    Science.gov (United States)

    Klapötke, Thomas M; Krumm, Burkhard; Scharf, Regina

    2016-11-07

    New energetic compounds have been synthesized starting from the readily available N-(cyanomethyl)-N-methylamine. From this, N-nitrosarcosine was prepared in few steps, which serves as a starting material for the synthesis of oxygen-rich compounds. The compounds were thoroughly characterized including multinuclear NMR and vibrational spectroscopy and also molecular structures by single X-ray diffraction were obtained. Their energetic properties were determined including the sensitivities towards impact and friction, their heat of formations were calculated and the detonation and combustion parameters were predicted using EXPLO5 V6.02. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Electrochemical synthesis of nanostructured materials for electrochemical energy conversion and storage.

    Science.gov (United States)

    Li, Gao-Ren; Xu, Han; Lu, Xue-Feng; Feng, Jin-Xian; Tong, Ye-Xiang; Su, Cheng-Yong

    2013-05-21

    Electrochemical synthesis represents a highly efficient method for the fabrication of nanostructured energy materials, and various nanostructures, such as nanorods, nanowires, nanotubes, nanosheets, dendritic nanostructures, and composite nanostructures, can be easily fabricated with advantages of low cost, low synthetic temperature, high purity, simplicity, and environmental friendliness. The electrochemical synthesis, characterization, and application of electrochemical energy nanomaterials have advanced greatly in the past few decades, allowing an increasing understanding of nanostructure-property-performance relationships. Herein, we highlight some recent progress in the electrochemical synthesis of electrochemical energy materials with the assistance of additives and templates in solution or grafted onto metal or conductive polymer supports, with special attention to the effects on surface morphologies, structures and, more importantly, electrochemical performance. The methodology for preparing novel electrochemical energy nanomaterials and their potential applications has been summarized. Finally, we outline our personal perspectives on the electrochemical synthesis and applications of electrochemical energy nanomaterials.

  11. Nanostructured Semiconductor Materials for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Carmen Cavallo

    2017-01-01

    Full Text Available Since O’Regan and Grätzel’s first report in 1991, dye-sensitized solar cells (DSSCs appeared immediately as a promising low-cost photovoltaic technology. In fact, though being far less efficient than conventional silicon-based photovoltaics (being the maximum, lab scale prototype reported efficiency around 13%, the simple design of the device and the absence of the strict and expensive manufacturing processes needed for conventional photovoltaics make them attractive in small-power applications especially in low-light conditions, where they outperform their silicon counterparts. Nanomaterials are at the very heart of DSSC, as the success of its design is due to the use of nanostructures at both the anode and the cathode. In this review, we present the state of the art for both n-type and p-type semiconductors used in the photoelectrodes of DSSCs, showing the evolution of the materials during the 25 years of history of this kind of devices. In the case of p-type semiconductors, also some other energy conversion applications are touched upon.

  12. Energetic N-Nitramino/N-Oxyl-Functionalized Pyrazoles with Versatile π-π Stacking: Structure-Property Relationships of High-Performance Energetic Materials.

    Science.gov (United States)

    Yin, Ping; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

    2016-11-07

    N-Nitramino/N-oxyl functionalization strategies were employed to investigate structure-property relationships of energetic materials. Based on single-crystal diffraction data, π-π stacking of pyrazole backbones can be tailored effectively by energetic functionalities, thereby resulting in diversified energetic compounds. Among them, hydroxylammonium 4-amino-3,5-dinitro-1H-pyrazol-1-olate and dipotassium N,N'-(3,5-dinitro-1H-pyrazol-1,4-diyl)dinitramidate, with unique face-to-face π-π stacking, can be potentially used as a high-performance explosive and an energetic oxidizer, respectively. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Nanostructured Lead Compounds in Electrode Materials of a Lead-Acid Battery

    Directory of Open Access Journals (Sweden)

    A.P. Kuzmenko

    2016-11-01

    Full Text Available The nanostructure and phase composition of the electrode material of lead-acid batteries, formed by chemical transformations with involvement of sulfuric acid solutions of various concentrations, water and carbon dioxide have been studied.

  14. The development of biopolymer-based nanostructured materials : plastics, gels, IPNs and nanofoams

    NARCIS (Netherlands)

    Soest, van J.J.G.

    2006-01-01

    The ability to design products with structural features on a nanometric scale is a major technology driver in materials research Nanostructured materials are defined as materials with structural features on a sub-micron scale determining specific properties They consist of materials such as metals,

  15. The development of biopolymer-based nanostructured materials : plastics, gels, IPNs and nanofoams

    NARCIS (Netherlands)

    Soest, van J.J.G.

    2006-01-01

    The ability to design products with structural features on a nanometric scale is a major technology driver in materials research Nanostructured materials are defined as materials with structural features on a sub-micron scale determining specific properties They consist of materials such as metals,

  16. Nanostructures formed on carbon-based materials with different levels of crystallinity using oxygen plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Tae-Jun [Institute for Multidisciplinary Convergence of Matter, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Jo, Wonjin; Lee, Heon Ju [Institute for Multidisciplinary Convergence of Matter, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Oh, Kyu Hwan [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Moon, Myoung-Woon, E-mail: mwmoon@kist.re.kr [Institute for Multidisciplinary Convergence of Matter, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

    2015-09-01

    Nanostructure formation was explored for various carbon-based materials, such as diamond, carbon fiber, polyethylene terephthalate and poly (methyl methacrylate), which have different levels of crystallinity, ranging from perfect crystal to polymeric amorphous. After treatment of oxygen plasma glow discharge, the nanostructures on these carbon-based materials were found to evolve via preferential etching due to the co-deposition of metal elements sputtered from the metal cathode plate. Local islands or clusters formed by the metal co-deposition have a low etching rate compared to pristine regions on each material, resulting in anisotropic patterns on the carbon-based materials. This pattern formation mechanism was confirmed by covering the cathode or preventing the co-deposition of metallic sources with a polymeric material. Regardless of the level of crystallinity of the carbon-based materials, no patterns were observed on the surfaces covered with the polymeric material, and the surfaces were uniformly etched. It was found that the materials with low crystallinity had a high etching rate due to low carbon atom density, which thus easily formed high-aspect-ratio nanostructures for the same plasma treatment duration. - Highlight: • Reactive ion etching & metal deposition were occurred in oxygen plasma treatment. • High-aspect-ratio nanostructures can be fabricated on carbon-based materials. • Materials with low crystallinity easily formed high-aspect-ratio nanostructure. • Amount of etching inhibitors affects the pattern formation and configuration.

  17. Development of numerical framework to study microstructural effects on shock initiation in heterogeneous energetic materials

    Science.gov (United States)

    Schmidt, Martin; Rai, Nirmal; Udaykumar, H. S.

    2015-06-01

    Heterogeneous energetic materials like plastic bonded explosives (PBX) have very detailed and non-uniform microstructure. The heterogeneity is mainly because of presence of HMX crystals embedded in a polymer binder matrix. Also, manufacturing defects often creates pores and cracks in the material. Shock interaction with these heterogeneities leads to local heated regions known as hot spots. It is widely accepted that these hot spots are predominantly the cause of triggering reaction and eventually ignition in these energetic materials. There are various physical phenomenon through which hot spot can be created such as pore collapse, inter-granular friction in HMX crystals, shock heating of HMX crystals and binder etc. Hence, microstructural heterogeneity can play a vital role for shock initiation in PBX. In the current work, a general framework has been established for performing mesoscale simulations on heterogeneous energetic material. In order to get an accurate representation of the microstructure, image processing algorithms have been employed on XCMT images of PBX microstructure. The image processing framework has been built up with massively parallel Eulerian code, SCIMITAR3D. Shock simulation on PBX microstructures has been performed and the effect of microstructure geometry has been studied for different shock strengths case. The simulation results have been shown to resolve hot spots created due to various heterogeneities present in the microstructure.

  18. Computational survey of representative energetic materials as propellants for microthruster applications

    Science.gov (United States)

    Fuchs, Brian; Stec, Daniel, III

    2007-04-01

    Microthrusters are critical for the development of terrestrial micromissiles and nano air vehicles for reconnaissance, surveillance, and sensor emplacement. With the maturation of MEMS manufacturing technology, the physical components of the thrusters can be readily fabricated. The thruster type that is the most straightforward is chemical combustion of a propellant that is ignited by a heating element giving a single shot thrust. Arrays of MEMS manufactured thrusters can be ganged to give multiple firings. The basic model for such a system is a solid rocket motor. The desired elements for the propellant of a chemical thruster are high specific impulse (I sp), high temperature and pressure, and low molecular weight combustion gases. Since the combustion chamber of a microthruster is extremely small, the propellant material must be able to ignite, sustain and complete its burn inside the chamber. The propellant can be either a solid or a liquid. There are a large number of energetic materials available as candidates for a propellant for microthrusters. There has been no systematic evaluation of the available energetic materials as propellant candidates for microthrusters. This report summarizes computations done on a series of energetic materials to address their suitabilities as microthruster propellants.

  19. Emissions from energetic material waste during the Molten Salt Destruction process

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, B.E.; Upadhye, R.S.; Pruneda, C.O.; Brummond, W.A.

    1994-07-05

    The Molten Salt Destruction (MSD) process is an alternative to open burn/open detonation for destroying energetic materials; MSD has inherently low gaseous emissions, and the salt bath can scrub both acidic gases and particulates. It was demonstrated that high explosives and a liquid propellant can be safely and completely destroyed using MSD. Gaseous emissions of NOx and CO are very low. Nitrate builds up in the salt bath when nitrate-rich materials are destroyed, but addition fuel reduces the nitrate to NO. A program has been begun to add catalytic materials to the bed to further reduce emissions; a small molten salt bath has been constructed for chemical kinetic studies.

  20. Effect of pressure vents on the fast cookoff of energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Marcia A.; Oliver, Michael S.; Erikson, William W

    2013-10-01

    The effect of vents on the fast cookoff of energetic materials is studied through experimental modifications to the confinement vessel of the Radiant Heat Fast Cookoff Apparatus. Two venting schemes were investigated: 1) machined grooves at the EM-cover plate interface; 2) radial distribution of holes in PEEK confiner. EM materials of PBXN-109 and PBX 9502 were tested. Challenges with the experimental apparatus and EM materials were identified such that studying the effect of vents as an independent parameter was not realized. The experimental methods, data and post-test observations are presented and discussed.

  1. Unreacted equation of states of typical energetic materials under static compression: A review

    Science.gov (United States)

    Zhaoyang, Zheng; Jijun, Zhao

    2016-07-01

    The unreacted equation of state (EOS) of energetic materials is an important thermodynamic relationship to characterize their high pressure behaviors and has practical importance. The previous experimental and theoretical works on the equation of state of several energetic materials including nitromethane, 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), hexanitrostilbene (HNS), hexanitrohexaazaisowurtzitane (HNIW or CL-20), pentaerythritol tetranitrate (PETN), 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), triamino-trinitrobenzene (TATB), 1,1-diamino-2,2-dinitroethene (DADNE or FOX-7), and trinitrotoluene (TNT) are reviewed in this paper. The EOS determined from hydrostatic and non-hydrostatic compressions are discussed and compared. The theoretical results based on ab initio calculations are summarized and compared with the experimental data. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174045 and 11404050).

  2. Potential space debris shield structure using impact-initiated energetic materials composed of polytetrafluoroethylene and aluminum

    Science.gov (United States)

    Wu, Qiang; Zhang, Qingming; Long, Renrong; Zhang, Kai; Guo, Jun

    2016-03-01

    A whipple shield using Al/PTFE (polytetrafluoroethylene) energetic material to protect against space debris is presented. The hypervelocity impact characteristics were investigated experimentally using a two-stage light gas gun at velocities between 3 and 6 km/s. A good protection of the shield was obtained through comparative experiments which used the same bumper areal density. The results showed that the critical projectile diameter can be improved by 28% by contrast with the Christiansen ballistic limit equations. The Al/PTFE energetic material bumper can break up the projectile into smaller, less massive, and slower projectiles due to the combined effect of impact and explosion, thereby producing a sharp rise in the spacecraft protection ability.

  3. Damaging impacts of energetic charge particles on materials in plasma energy explosive events

    Institute of Scientific and Technical Information of China (English)

    Deng Bai-Quan; Peng Li-Lin; Yan Jian-Cheng; Luo Zheng-Ming; Chen Zhi

    2006-01-01

    To provide some reference data for estimation of the erosion rates and lifetimes of some candidate plasma facing component (PF3 materials in the plasma stored energy explosive events (PSEEE), this paper calculates the sputtering yields of Mo, W and deuterium saturated Li surface bombarded by energetic charged particles by a new sputtering physics description method based on bipartition model of charge particle transport theory. The comparisons with Monte Carlo data of TRIM code and experimental results are made. The dependences of maximum energy deposition,particle and energy reflection coefficients on the incident energy of energetic runaway electrons impinging on the different material surfaces are also calculated. Results may be useful for estimating the lifetime of PFC and analysing the impurity contamination extent, especially in the PSEEE for high power density and with high plasma current fusion reactor.

  4. Fabrication of bioinspired nanostructured materials via colloidal self-assembly

    Science.gov (United States)

    Huang, Wei-Han

    ultimate strains than nacre and pure GO paper (also synthesized by filtration). Specifically, it exhibits ˜30 times higher fracture energy than filtrated graphene paper and nacre, ˜100 times tougher than filtrated GO paper. Besides reinforced nanocomposites, we further explored the self-assembly of spherical colloids and the templating nanofabrication of moth-eye-inspired broadband antireflection coatings. Binary crystalline structures can be easily accomplished by spin-coating double-layer nonclose-packed colloidal crystals as templates, followed by colloidal templating. The polymer matrix between self-assembled colloidal crystal has been used as a sacrificial template to define the resulting periodic binary nanostructures, including intercalated arrays of silica spheres and polymer posts, gold nanohole arrays with binary sizes, and dimple-nipple antireflection coatings. The binary-structured antireflection coatings exhibit better antireflective properties than unitary coatings. Natural optical structures and nanocomposites teach us a great deal on how to create high performance artificial materials. The bottom-up technologies developed in this thesis are scalable and compatible with standard industrial processes, promising for manufacturing high-performance materials for the benefits of human beings.

  5. Quantitative Scanning Transmission Electron Microscopy of Electronic and Nanostructured Materials

    Science.gov (United States)

    Yankovich, Andrew B.

    Electronic and nanostructured materials have been investigated using advanced scanning transmission electron microscopy (STEM) techniques. The first topic is the microstructure of Ga and Sb-doped ZnO. Ga-doped ZnO is a candidate transparent conducting oxide material. The microstructure of GZO thin films grown by MBE under different growth conditions and different substrates were examined using various electron microscopy (EM) techniques. The microstructure, prevalent defects, and polarity in these films strongly depend on the growth conditions and substrate. Sb-doped ZnO nanowires have been shown to be the first route to stable p-type ZnO. Using Z-contrast STEM, I have showed that an unusual microstructure of Sb-decorated head-to-head inversion domain boundaries and internal voids contain all the Sb in the nanowires and cause the p-type conduction. InGaN thin films and InGaN / GaN quantum wells (QW) for light emitting diodes are the second topic. Low-dose Z-contrast STEM, PACBED, and EDS on InGaN QW LED structures grown by MOCVD show no evidence for nanoscale composition variations, contradicting previous reports. In addition, a new extended defect in GaN and InGaN was discovered. The defect consists of a faceted pyramid-shaped void that produces a threading dislocation along the [0001] growth direction, and is likely caused by carbon contamination during growth. Non-rigid registration (NRR) and high-precision STEM of nanoparticles is the final topic. NRR is a new image processing technique that corrects distortions arising from the serial nature of STEM acquisition that previously limited the precision of locating atomic columns and counting the number of atoms in images. NRR was used to demonstrate sub-picometer precision in STEM images of single crystal Si and GaN, the best achieved in EM. NRR was used to measure the atomic surface structure of Pt nanoacatalysts and Au nanoparticles, which revealed new bond length variation phenomenon of surface atoms. In

  6. Structural and vibrational properties of nitrogen-rich energetic material guanidinium 2-methyl-5-nitraminotetrazolate

    OpenAIRE

    Babu, K Ramesh; Vaitheeswaran, G.

    2014-01-01

    We present density functional theory calculations on the crystal structure, equation of state, vibrational properties and electronic structure of nitrogen-rich solid energetic material guanidinium 2-methyl-5-nitraminotetrazolate (G-MNAT). The ground state structural properties calculated with dispersion corrected density functionals are in good agreement with experiment. The computed equilibrium crystal structure is further used to calculate the equation of state and zone-center vibrational f...

  7. Explosive Chemistry: Simulating the Chemistry of Energetic Materials at Extreme Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Reed, E J; Manaa, M R; Fried, L E

    2003-11-18

    In the brief instant of a high-explosive detonation, the shock wave produces a pressure 500,000 times that of the Earth's atmosphere, the detonation wave travels as fast as 10 kilometers per second, and internal temperatures soar up to 5,500 Kelvin. As the shock propagates through the energetic material, the rapid heating coupled with compression that results in almost 30% volume reduction, initiate complex chemical reactions. A dense, highly reactive supercritical fluid is established behind the propagating detonation front. Energy release from the exothermic chemical reactions serve in turn to drive and sustain the detonation process until complete reactivity is reached. Several experimental results suggest the existence of strong correlations between the applied mechanical stress and shocks, the local heterogeneity and defects (dislocations, vacancies, cracks, impurities, etc.), and the onset of chemical reactions. The reaction chemistry of energetic materials at high pressure and temperature is, therefore, of considerable importance in understanding processes that these materials experience under impact and detonation conditions. Chemical decomposition models are critical ingredients in order to predict, among other things, the measured times to explosion and the conditions for ignition of hot spots, localized regions of highly concentrated energy associated with defects. To date, chemical kinetic rates of condense-phase energetic materials at detonation conditions are virtually non-existent, and basic questions such as: (a) which bond in a given energetic molecule breaks first, and (b) what type of chemical reactions (unimolecular versus bimolecular, etc.) that dominate early in the decomposition process, are still largely unknown.

  8. Microscale electromagnetic heating in heterogeneous energetic materials based on X-ray CT imaging

    CERN Document Server

    Kort-Kamp, W J M; Ionita, A; Glover, B B; Duque, A L Higginbotham; Perry, W L; Patterson, B M; Dalvit, D A R; Moore, D S

    2015-01-01

    Electromagnetic stimulation of energetic materials provides a noninvasive and nondestructive tool for detecting and identifying explosives. We combine structural information based on X-ray computed tomography, experimental dielectric data, and electromagnetic full-wave simulations, to study microscale electromagnetic heating of realistic three-dimensional heterogeneous explosives. We analyze the formation of electromagnetic hot spots and thermal gradients in the explosive-binder meso-structures, and compare the heating rate for various binder systems.

  9. Isotope abundances of solar coronal material derived from solar energetic particle measurements

    Science.gov (United States)

    Mewaldt, R. A.; Stone, E. C.

    1989-01-01

    Coronal isotopic abundances for the elements He, C, N, O, Ne, and Mg are derived from previously published measurements of the isotopic composition of solar energetic particles by first measuring, and then correcting for, the charge-to-mass-dependent fractionation due to solar flare acceleration and propagation processes. The resulting coronal composition generally agrees with that of other samples of solar system material, but the previously noted difference between the solar flare and solar wind Ne-22/Ne-20 ratios remains unresolved.

  10. Energetic materials research and development activities at Sandia National Laboratories supported under DP-10 programs

    Energy Technology Data Exchange (ETDEWEB)

    Ratzel, A.C. III

    1998-09-01

    This report provides summary descriptions of Energetic Materials (EM) Research and Development activities performed at Sandia National Laboratories and funded through the Department of Energy DP-10 Program Office in FY97 and FY98. The work falls under three major focus areas: EM Chemistry, EM Characterization, and EM Phenomenological Model Development. The research supports the Sandia component mission and also Sandia's overall role as safety steward for the DOE Nuclear Weapons Complex.

  11. Experimental Investigation of the Role of Defects in Detonation Sensitivity of Energetic Materials: Development of Techniques for Characterization

    Science.gov (United States)

    2008-03-04

    Chein . B 2007, 111, 3430-3437 Computer Simulations and Analysis of Structural and Energetic Features of Some Crystalline Energetic Materials Craig J...B, Vol. I H, No. 13, 2007 3437 Brand, H. V. Combust. Flame 2002. 130, 185-203. (c) Taylor, J. W.; (11) (a) Gavezzotti, A. J1 Phys. Chein . B 2002, 106

  12. Morphology and interfacial energetics controls for hierarchical anatase/rutile TiO2 nanostructured array for efficient photoelectrochemical water splitting.

    Science.gov (United States)

    Yang, Jih-Sheng; Liao, Wen-Pin; Wu, Jih-Jen

    2013-08-14

    In this work, a three-dimensional (3D) hierarchical TiO2 nanostructured array is constructed on the basis of the considerations of morphology and interfacial energetics for photoelectrochemical water splitting. The photoelectrode is composed of a core-shell structure where the core portion is a rutile TiO2 nanodendrite (ND) array and the shell portion is rutile and anatase TiO2 nanoparticles (NPs) sequentially located on the surface. The TiO2 ND array provides a fast electron transport pathway due to its quasi-single-crystalline structure. The 3D configuration with NPs in the shell portion provides a larger surface area for more efficient photocharge separation without significantly sacrificing the electron collection efficiency. Moreover, anatase TiO2 NPs constructed on the surface of the ND/rutile TiO2 NP nanostructured array enhance charge separation and suppress charge recombination at the interfacial region due to the higher conduction band edge of anatase TiO2 compared to that of rutile TiO2. A photocurrent density and photoconversion efficiency of 2.08 mA cm(-2) at 1.23 V vs reversible hydrogen electrode (RHE) and 1.13% at 0.51 V vs RHE are, respectively, attained using the hierarchical TiO2 nanostructured array photoelectrochemical cell under illumination of AM 1.5G (100 mW cm(-2)).

  13. Meeting the challenge of characterizing emissions produced by burning chlorinated energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, J.L. [Army West Desert Test Center, Dugway, UT (United States); Bacon, D.P. [ECO, L.C., Salt Lake City, UT (United States)

    1996-12-01

    As the US Environmental Protection Agency (USEPA) and state regulators increase the stringency and enforcement of regulations concerning emissions produced by open-air detonation of energetic materials, research must provide the means of obtaining emissions data. The BangBox emissions testing program established the technical foundations for emissions characterization which have been accepted by the USEPA and other regulatory agencies; the technical issues remaining are nettlesome and require new approaches in test procedures. Characterizing emissions produced by the open burning (OB) or open detonation (OD) of chlorine-containing energetics is an excellent example. Highly reactive, chlorine combines with a number of materials found in most testing environments, e.g., metal in sampling devices and moisture in the air, thus greatly complicating the testing situation. This paper describes the materials tested, special considerations in preparing the test facility, the means used to account for chlorine, and preliminary results of a developmental test on solid rocket-motor propellants conducted in July and August 1995 at the BangBox test facility at the US Army West Desert Test Center in Utah. The paper also projects how the creative processes used in developing the means for testing chlorine-containing energetics can be applied in resolving other emissions-data needs of the explosives industry such as supporting OB/OD permit applications and responding to notices of deficiency and notices of violation.

  14. Searching for new energetic materials: Computational design of novel nitro-substituted heterocyclic explosives

    Science.gov (United States)

    Tsyshevsky, Roman V.; Pagoria, Philip; Kuklja, Maija M.

    2017-01-01

    The continuous search for safe and powerful energetic materials is an exciting research challenge that attracts experts in material science, chemistry, physics, and engineering. Elucidation of meaningful relationships between sensitivity and structures of explosives is a fundamental problem, which needs to be addressed to ensure successful design of new materials and improvements of existing energetics. In this paper, quantum-chemical DFT study of thermal decomposition of a series of recently synthesized oxadiazole-based explosives, BNFF (3,4-bis(4-Nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole-N-oxide), BNFF-1 (3,4-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole) and ANFF-1 (3-(4-amino-1,2,5-oxadiazol-3-yl)-4-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole) is presented. We also show how the knowledge of discovered interplay between the structures and thermal stability of these compounds is used to design several novel candidate heterocyclic energetic molecules, including DNBTT (2,7-dinitro-4H,9H-bis([1,2,4]triazolo)[1,5-b:1',5'-e][1,2,4,5]tetrazine), the compound with high thermal stability, which is on predicted to be par or better than that of TATB.

  15. Experimental Study on Reaction Characteristics of PTFE/Ti/W Energetic Materials under Explosive Loading

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-11-01

    Full Text Available Metal/fluoropolymer composites represent a new category of energetic structural materials that release energy through exothermic chemical reactions initiated under shock loading conditions. This paper describes an experiment designed to study the reaction characteristics of energetic materials with low porosity under explosive loading. Three PTFE (polytetrafluoroethylene/Ti/W mixtures with different W contents are processed through pressing and sintering. An inert PTFE/W mixture without reactive Ti particles is also prepared to serve as a reference. Shock-induced chemical reactions are recorded by high-speed video through a narrow observation window. Related shock parameters are calculated based on experimental data, and differences in energy release are discussed. The results show that the reaction propagation of PTFE/Ti/W energetic materials with low porosity under explosive loading is not self-sustained. As propagation distance increases, the energy release gradually decreases. In addition, reaction failure distance in PTFE/Ti/W composites is inversely proportional to the W content. Porosity increased the failure distance due to higher shock temperature.

  16. Experimental Study on Reaction Characteristics of PTFE/Ti/W Energetic Materials under Explosive Loading.

    Science.gov (United States)

    Li, Yan; Jiang, Chunlan; Wang, Zaicheng; Luo, Puguang

    2016-11-18

    Metal/fluoropolymer composites represent a new category of energetic structural materials that release energy through exothermic chemical reactions initiated under shock loading conditions. This paper describes an experiment designed to study the reaction characteristics of energetic materials with low porosity under explosive loading. Three PTFE (polytetrafluoroethylene)/Ti/W mixtures with different W contents are processed through pressing and sintering. An inert PTFE/W mixture without reactive Ti particles is also prepared to serve as a reference. Shock-induced chemical reactions are recorded by high-speed video through a narrow observation window. Related shock parameters are calculated based on experimental data, and differences in energy release are discussed. The results show that the reaction propagation of PTFE/Ti/W energetic materials with low porosity under explosive loading is not self-sustained. As propagation distance increases, the energy release gradually decreases. In addition, reaction failure distance in PTFE/Ti/W composites is inversely proportional to the W content. Porosity increased the failure distance due to higher shock temperature.

  17. Sensitivity Characterization of Pressed Energetic Materials using Flyer Plate Mesoscale Simulations

    Science.gov (United States)

    Rai, Nirmal; Udaykumar, H. S.

    Heterogeneous energetic materials like pressed explosives have complicated microstructure and contain various forms of heterogeneities such as pores, micro-cracks, energetic crystals etc. It is widely accepted that the presence of these heterogeneities can affect the sensitivity of these materials under shock load. The interaction of shock load with the microstructural heterogeneities may leads to the formation of local heated regions known as ``hot spots''. Chemical reaction may trigger at the hot spot regions depending on the hot spot temperature and the duration over which the temperature can be maintained before phenomenon like heat conduction, rarefaction waves withdraws energy from it. There are different mechanisms which can lead to the formation of hot spots including void collapse. The current work is focused towards the sensitivity characterization of two HMX based pressed energetic materials using flyer plate mesoscale simulations. The aim of the current work is to develop mesoscale numerical framework which can perform simulations by replicating the laboratory based flyer plate experiments. The current numerical framework uses an image processing approach to represent the microstructural heterogeneities incorporated in a massively parallel Eulerian code SCIMITAR3D. The chemical decomposition of HMX is modeled using Henson-Smilowitz reaction mechanism. The sensitivity characterization is aimed towards obtaining James initiation threshold curve and comparing it with the experimental results.

  18. Cooperative enhancement of the nonlinear optical response in conjugated energetic materials: A TD-DFT study.

    Science.gov (United States)

    Sifain, Andrew E; Tadesse, Loza F; Bjorgaard, Josiah A; Chavez, David E; Prezhdo, Oleg V; Scharff, R Jason; Tretiak, Sergei

    2017-03-21

    Conjugated energetic molecules (CEMs) are a class of explosives with high nitrogen content that posses both enhanced safety and energetic performance properties and are ideal for direct optical initiation. As isolated molecules, they absorb within the range of conventional lasers. Crystalline CEMs are used in practice, however, and their properties can differ due to intermolecular interaction. Herein, time-dependent density functional theory was used to investigate one-photon absorption (OPA) and two-photon absorption (TPA) of monomers and dimers obtained from experimentally determined crystal structures of CEMs. OPA scales linearly with the number of chromophore units, while TPA scales nonlinearly, where a more than 3-fold enhancement in peak intensity, per chromophore unit, is calculated. Cooperative enhancement depends on electronic delocalization spanning both chromophore units. An increase in sensitivity to nonlinear laser initiation makes these materials suitable for practical use. This is the first study predicting a cooperative enhancement of the nonlinear optical response in energetic materials composed of relatively small molecules. The proposed model quantum chemistry is validated by comparison to crystal structure geometries and the optical absorption of these materials dissolved in solution.

  19. Development of quantitative structure property relationships for predicting the melting point of energetic materials.

    Science.gov (United States)

    Morrill, Jason A; Byrd, Edward F C

    2015-11-01

    The accurate prediction of the melting temperature of organic compounds is a significant problem that has eluded researchers for many years. The most common approach used to develop predictive models entails the derivation of quantitative structure-property relationships (QSPRs), which are multivariate linear relationships between calculated quantities that are descriptors of molecular or electronic features and a property of interest. In this report the derivation of QSPRs to predict melting temperatures of energetic materials based on descriptors calculated using the AM1 semiempirical quantum mechanical method are described. In total, the melting points and experimental crystal structures of 148 energetic materials were analyzed. Principal components analysis was performed in order to assess the relative importance and roles of the descriptors in our QSPR models. Also described are the results of k means cluster analysis, performed in order to identify natural groupings within our study set of structures. The QSPR models resulting from these analyses gave training set R(2) values of 0.6085 (RMSE = ± 15.7 °C) and 0.7468 (RMSE = ± 13.2 °C). The test sets for these clusters had R(2) values of 0.9428 (RMSE = ± 7.0 °C) and 0.8974 (RMSE = ± 8.8 °C), respectively. These models are among the best melting point QSPRs yet published for energetic materials. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Growth and energetics in Spisula subtruncata (Da Costa) and the effect of suspended bottom material

    DEFF Research Database (Denmark)

    Møhlenberg, F.; Kiørboe, Thomas

    1981-01-01

    The influence of suspended bottom material (0-25 mg/l) and algal cells (Phaeodactylum tricornutum) (0-500 .mu.g dry org wt[organic weight]/l) on clearance, growth and energetics in S. subtruncata (da Costa) was studied. Clearance and respiration rate were independent of concentrations of algae...... and suspended bottom material. Algal ingestion rate was proportional to algal concentration and independent of the concentration of suspended bottom material. Growth rate increased with algal concentration and was further increased by 10-110% by adding suspended bottom material. The positive effect of suspended...... bottom material on growth is due to a higher efficiency of assimilation of the ingested algae and/or the utilization of organic matter in the suspended bottom material. The efficiency of algal assimilation decreased from 76% at a low (150 .mu.g dry org wt/l) to 33% at a high (500 .mu.g) algal...

  1. Fabrication and characterization of nanostructured titanate materials by the hydrothermal treatment method.

    Science.gov (United States)

    Doong, Ruey-an; Kao, I-ling

    2008-01-01

    The synthesis and characterization of one-dimensional (1-D) tubular and fibrous nanostructured materials have recently received highly attention. Various morphologies of 1-D nanostructured titanate materials including nanosheets, nanotubes, nanowires, and nanoribbons have recently been successfully synthesized using the alkaline hydrothermal method. In spite of the controversy of the chemical structures and formation mechanisms, titanate nanostructures have attracted much attention on applications of dye-sensitized solar cell, hydrogen sensing, lithium storage and photocatalysis because of their unique features of high specific surface area, ion-exchange capacity and aspect ratio, and unique optical and electrochemical properties. The morphology and microstructure of titanate nanostructures are highly dependent on the preparation conditions. In this review, we highlight the synthesis of TiO(2)-derived nanomaterials under various hydrothermal conditions. The patents for fabrication of various morphologies of nanostructures are also introduced. Effects of preparation parameters including hydrothermal temperature, duration, alkaline concentration, starting materials, and post-treatment on the morphology and microstructure of titanate nanomaterials are reviewered. In addition, the microwave-assisted method for fabrication of 1-D titanate nanostructures is discussed and compared. The applications of titanate nanomaterials in photocatalysis, ion-exchange, and lithium storages are also introduced.

  2. Energetic multifunctionalized nitraminopyrazoles and their ionic derivatives: ternary hydrogen-bond induced high energy density materials.

    Science.gov (United States)

    Yin, Ping; Parrish, Damon A; Shreeve, Jean'ne M

    2015-04-15

    Diverse functionalization was introduced into the pyrazole framework giving rise to a new family of ternary hydrogen-bond induced high energy density materials. By incorporating extended cationic interactions, nitramine-based ionic derivatives exhibit good energetic performance and enhanced molecular stability. Performance parameters including heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 v6.01 programs, respectively. It is noteworthy to find that 5-nitramino-3,4-dinitropyrazole, 4, has a remarkable measured density of 1.97 g cm(-3) at 298 K, which is consistent with its crystal density (2.032 g cm(-3), 150 K), and ranks highest among azole-based CHNO compounds. Energetic evaluation indicates that, in addition to the molecular compound 4, some ionic derivatives, 9, 11, 12, 17, 19, and 22, also have high densities (1.83-1.97 g cm(-3)), excellent detonation pressures and velocities (P, 35.6-41.6 GPa; vD, 8880-9430 m s(-1)), as well as acceptable impact and friction sensitivities (IS, 4-30 J; FS, 40-240 N). These attractive features highlight the application potential of nitramino hydrogen-bonded interactions in the design of advanced energetic materials.

  3. Photoelectron spectroscopy and density functional theory studies of N-rich energetic materials.

    Science.gov (United States)

    Zeng, Zhen; Bernstein, Elliot R

    2016-10-28

    The geometric and electronic structures of molecular anionic energetic materials (EMs) DAAF (3,3'-diamino-4,4'-azoxyfurazan), FOX-7 (1,1-diamino-2,2-dinitroethene), 5,5'-BT (5,5'-bistetrazole), and 1,5'-BT (1,5'-bistetrazole) are explored employing anionic photoelectron spectroscopy and density functional theory calculations. The electron binding energies of the observed anionic, energetic material related species are determined and their corresponding anionic structures are assigned. Decomposition reactions for negatively charged EMs can proceed with different energy barriers, and thus mechanisms, from those for their related neutral EMs. Reactivity based on the anionic initial fragments of these EM species further reinforces their respective highly reactive and explosive nature. Fragment ions of the form EM(-)-H-X (X = N2, N2+NH, …) are additionally observed. Detection of such species suggests that EM(-)-H could serve as promising new candidates for EMs, assuming that such species are synthetically available, perhaps as energetic salts. Vertical detachment energies for transitions to the ground and first triplet electronic excited states of neutral matrix dye anion DCM(-) are additionally determined.

  4. Photoelectron spectroscopy and density functional theory studies of N-rich energetic materials

    Science.gov (United States)

    Zeng, Zhen; Bernstein, Elliot R.

    2016-10-01

    The geometric and electronic structures of molecular anionic energetic materials (EMs) DAAF (3,3'-diamino-4,4'-azoxyfurazan), FOX-7 (1,1-diamino-2,2-dinitroethene), 5,5'-BT (5,5'-bistetrazole), and 1,5'-BT (1,5'-bistetrazole) are explored employing anionic photoelectron spectroscopy and density functional theory calculations. The electron binding energies of the observed anionic, energetic material related species are determined and their corresponding anionic structures are assigned. Decomposition reactions for negatively charged EMs can proceed with different energy barriers, and thus mechanisms, from those for their related neutral EMs. Reactivity based on the anionic initial fragments of these EM species further reinforces their respective highly reactive and explosive nature. Fragment ions of the form EM--H-X (X = N2, N2+NH, …) are additionally observed. Detection of such species suggests that EM--H could serve as promising new candidates for EMs, assuming that such species are synthetically available, perhaps as energetic salts. Vertical detachment energies for transitions to the ground and first triplet electronic excited states of neutral matrix dye anion DCM- are additionally determined.

  5. New high-nitrogen energetic materials for gas generators in space ordnance

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, M.S.; Lee, Kien-Yin; Hiskey, M.A.

    1995-08-01

    High-nitrogen nitroheterocyclic energetic compounds are used as explosives, propellants, and gas generants when safe, thermally stable, cool-burning energetic materials are desired. A series of compounds are compared for sensitivity properties and calculated burn performance. Thermodynamic equilibrium calculations by NASA/Lewis rocket propellant and Blake gun propellant codes gave flame temperatures, average molecular weight, and identity of the equilibrium burn products for ambient, rocket, and gun pressure environments. These compounds were subjected to calculations both as monopropellants and as 50/50 weight ratio mixtures with ammonium nitrate (AN). Special attention was paid to calculated toxic products such as carbon monoxide and hydrogen cyanide, and how these were affected by the addition of an oxidizer AN. Several compounds were noted for further calculations of a formulation ad experimental evaluation.

  6. Quantum Simulations of Materials and Nanostructures (Q-SIMAN). Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Galli, Giulia [Univ. of California, Davis, CA (United States); Bai, Zhaojun [Univ. of California, Davis, CA (United States); Ceperley, David [Univ. of Illinois, Urbana, IL (United States); Cai, Wei [Stanford Univ., CA (United States); Gygi, Francois [Univ. of California, Davis, CA (United States); Marzari, Nicola [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Pickett, Warren [Univ. of California, Davis, CA (United States); Spaldin, Nicola [Univ. of California, Santa Barbara, CA (United States); Fattebert, Jean-Luc [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schwegler, Eric [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-16

    The focus of this SciDAC SAP (Scientific Application) is the development and use of quantum simulations techniques to understand materials and nanostructures at the microscopic level, predict their physical and chemical properties, and eventually design integrated materials with targeted properties. (Here the word ‘materials’ is used in a broad sense and it encompasses different thermodynamic states of matter, including solid, liquids and nanostructures.) Therefore our overarching goal is to enable scientific discoveries in the field of condensed matter and advanced materials through high performance computing.

  7. Laser-shocked energetic materials with metal additives: evaluation of detonation performance

    Science.gov (United States)

    Gottfried, Jennifer; Bukowski, Eric

    A focused, nanosecond-pulsed laser with sufficient energy to exceed the breakdown threshold of a material generates a laser-induced plasma with high peak temperatures, pressures, and shock velocities. Depending on the laser parameters and material properties, nanograms to micrograms of material is ablated, atomized, ionized and excited in the laser-induced plasma. The subsequent shock wave expansion into the air above the sample has been monitored using high-speed schlieren imaging in a recently developed technique, laser-induced air shock from energetic materials (LASEM). The estimated detonation velocities using LASEM agree well with published experimental values. A comparison of the measured shock velocities for various energetic materials including RDX, DNTF, and LLM-172 doped with Al or B to the detonation velocities predicted by CHEETAH for inert or active metal participation demonstrates that LASEM has potential for predicting the early time participation of metal additives in detonation events. The LASEM results show that reducing the amount of hydrogen present in B formulations increases the resulting detonation velocities

  8. Comparative Study of Various Pyrazole-based Anions: A Promising Family of Ionic Derivatives as Insensitive Energetic Materials.

    Science.gov (United States)

    Yin, Ping; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

    2017-02-01

    In the design of advanced energetic materials, high-density explosophores play a pivotal role because of their remarkable enhancement of both density and molecular stability. Using diversified functionalization strategies, a comparative study involving various nitropyrazole anions shows that these are crucially important in determining performance and stability. A promising family of pyrazole-based energetic ionic derivatives were synthesized and characterized by NMR and IR spectroscopies, and elemental analysis. Among them, 7, 8, 11-13 exhibit favorable overall performance as energetic materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The Effects of Surface Properties of Nanostructured Bone Repair Materials on Their Performances

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-01-01

    Full Text Available Nanotechnology has been expected to be an extraordinarily promising method for bone repair. Meanwhile, the promise of nanobiomaterials for therapeutic applications has been widely reported, and a lot of studies have been made in terms of repairing bone using nanomaterials accompanied by rapid development of nanotechnology. Compared with conventional biomaterials, nanostructured implants have been shown to possess positive effects on cellular functions because of their unique surface properties, such as nanotopography, increased wettability, larger surface area, and microenvironment similar to extracellular matrix. Moreover, many positive cellular responses have been found to take place at the interface between nanostructured implants and host bone. In this paper, we will give a review about the effects of surface properties of nanostructured bone repair materials on their performances in terms of several aspects and a detailed interpretation or introduction on the specific cellular recognitions at the interface between nanostructured implants and host bone.

  10. Towards the Industrial Application of Spark Ablation for Nanostructured Functional Materials

    NARCIS (Netherlands)

    Pfeiffer, T.V.

    2014-01-01

    Nanostructuring of functional materials is an essential part in the design of energy related devices – but the industrial tools we have to make these materials are lacking. This dissertation explores the green, flexible, and scalable spark discharge process for the fabrication of complex

  11. Towards the Industrial Application of Spark Ablation for Nanostructured Functional Materials

    NARCIS (Netherlands)

    Pfeiffer, T.V.

    2014-01-01

    Nanostructuring of functional materials is an essential part in the design of energy related devices – but the industrial tools we have to make these materials are lacking. This dissertation explores the green, flexible, and scalable spark discharge process for the fabrication of complex nanostructu

  12. Assembly and Characterization of Coordination Polymer Nanostructural Materials at Interfaces

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Molecular self-assembly of one-/two-dimensional (1D/2D) nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties. Coordination polymers contain two central components, connectors and linkers. Transition metal ions are often used as versatile connectors, with coordination numbers ranging from 2 to 7 dependant on the oxidation states of the metal ions. Multidentate ligands are often used as linkers, wh...

  13. A micro-macro coupling approach of MD-SPH method for reactive energetic materials

    Science.gov (United States)

    Liu, Gui Rong; Wang, Guang Yu; Peng, Qing; De, Suvranu

    2017-01-01

    The simulation of reactive energetic materials has long been the interest of researchers because of the extensive applications of explosives. Much research has been done on the subject at macro scale in the past and research at micro scale has been initiated recently. Equation of state (EoS) is the relation between physical quantities (pressure, temperature, energy and volume) describing thermodynamic states of materials under a given set of conditions. It plays a significant role in determining the characteristics of energetic materials, including Chapman-Jouguet point and detonation velocity. Furthermore, EoS is the key to connect microscopic and macroscopic phenomenon when simulating the macro effects of an explosion. For instance, an ignition and growth model for high explosives uses two JWL EoSs, one for solid explosive and the other for gaseous products, which are often obtained from experiments that can be quite expensive and hazardous. Therefore, it is ideal to calculate the EoS of energetic materials through computational means. In this paper, the EoSs for both solid and gaseous products of β-HMX are calculated using molecular dynamics simulation with ReaxFF-d3, a reactive force field obtained from quantum mechanics. The microscopic simulation results are then compared with experiments and the continuum ignition and growth model. Good agreement is observed. Then, the EoSs obtained through micro-scale simulation is applied in a smoothed particle hydrodynamics (SPH) code to simulate the macro effects of explosions. Simulation results are compared with experiments.

  14. The quest for greater chemical energy storage in energetic materials: Grounding expectations

    Science.gov (United States)

    Lindsay, C. Michael; Fajardo, Mario E.

    2017-01-01

    It is well known that the performance of modern energetic materials based on organic chemistry has plateaued, with only ˜ 40% improvements realized over the past half century. This fact has stimulated research on alternative chemical energy storage schemes in various U.S. government funded "High Energy Density Materials" (HEDM) programs since the 1950's. These efforts have examined a wide range of phenomena such as free radical stabilization, metallic hydrogen, metastable helium, polynitrogens, extended molecular solids, nanothermites, and others. In spite of the substantial research investments, significant improvements in energetic material performance have not been forthcoming. This paper discusses the lessons learned in the various HEDM programs, the different degrees of freedom in which to store energy in materials, and the fundamental limitations and orders of magnitude of the energies involved. The discussion focuses almost exclusively on the topic of energy density and only mentions in passing other equally important properties of explosives and propellants such as gas generation and reaction rate.

  15. Importance of the gas phase role to the prediction of energetic material behavior: An experimental study

    Science.gov (United States)

    Ali, A. N.; Son, S. F.; Asay, B. W.; Sander, R. K.

    2005-03-01

    Various thermal (radiative, conductive, and convective) initiation experiments are performed to demonstrate the importance of the gas phase role in combustion modeling of energetic materials (EM). A previously published condensed phase model that includes a predicted critical irradiance above which ignition is not possible is compared to experimental laser ignition results for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2,4,6-trinitrotoluene (TNT). Experimental results conflict with the predicted critical irradiance concept. The failure of the model is believed to result from a misconception about the role of the gas phase in the ignition process of energetic materials. The model assumes that ignition occurs at the surface and that evolution of gases inhibits ignition. High speed video of laser ignition, oven cook-off and hot wire ignition experiments captures the ignition of HMX and TNT in the gas phase. A laser ignition gap test is performed to further evaluate the effect of gas phase laser absorption and gas phase disruption on the ignition process. Results indicate that gas phase absorption of the laser energy is probably not the primary factor governing the gas phase ignition observations. It is discovered that a critical gap between an HMX pellet and a salt window of 6mm±0.4mm exists below which ignition by CO2 laser is not possible at the tested irradiances of 29W /cm2 and 38W/cm2 for HMX ignition. These observations demonstrate that a significant disruption of the gas phase, in certain scenarios, will inhibit ignition, independent of any condensed phase processes. These results underscore the importance of gas phase processes and illustrate that conditions can exist where simple condensed phase models are inadequate to accurately predict the behavior of energetic materials.

  16. Calculated Lattice Energies of Energetic Materials in a Prediction of their Heats of Fusion and Sublimation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper specifies an unambiguous basic relationship between the published results of ab initio calculations of lattice energies,EL,and heats of sublimation,ΔHs,of individual energetic materials. In this relationship,the ΔHs value has been replaced by heats of fusion,ΔHm,tr. Thereby its unambiguity has been lost,and the similarity of details of molecular structure begins to be of decisive importance. The resulting partial relationships,together with the basic relationship,have been used for prediction of ΔHs,and ΔHm,tr values of technically attractive polynitro compounds.

  17. Isentropic Compression Experiments Performed By LLNL On Energetic Material Samples Using The Z Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Vandersall, K S; Reisman, D B; Forbes, J W; Hare, D E; Garcia, F; Uphaus, T M; Elsholz, A J; Tarver, C M; Eggert, J H

    2007-10-25

    Several experiments have been conducted by LLNL researchers using isentropic compression experiments (ICE) on energetic materials as samples from Fiscal Year 2001 (FY01) to Fiscal Year 2005 (FY05). Over this span of time, advancements of the experimental techniques and modeling of the results have evolved to produce improved results. This report documents the experiments that have been performed, provides details of the results generated, and modeling and analysis advances to fully understand the results. Publications on the topics by the various principal investigators (PI's) are detailed in the Appendices for quick reference for the work as it progressed.

  18. Isotope-specific detection of low density materials with mono-energetic (gamma)-rays

    Energy Technology Data Exchange (ETDEWEB)

    Albert, F; Anderson, S G; Gibson, D J; Hagmann, C A; Johnson, M S; Messerly, M J; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P; Barty, C J

    2009-03-16

    The first demonstration of isotope-specific detection of a low-Z, low density object, shielded by a high-Z and high density material using mono-energetic gamma-rays is reported. Isotope-specific detection of LiH shielded by Pb and Al is accomplished using the nuclear resonance fluorescence line of {sup 7}Li at 0.478 MeV. Resonant photons are produced via laser-based Compton scattering. The detection techniques are general and the confidence level obtained is shown to be superior to that yielded by conventional x-ray/{gamma}-ray techniques in these situations.

  19. Eye-safe infrared laser-induced breakdown spectroscopy (LIBS) emissions from energetic materials

    Science.gov (United States)

    Brown, Ei E.; Hömmerich, Uwe; Yang, Clayton C.; Jin, Feng; Trivedi, Sudhir B.; Samuels, Alan C.

    2016-05-01

    Laser-induced breakdown spectroscopy is a powerful diagnostic tool for detection of trace elements by monitoring the atomic and ionic emission from laser-induced plasmas. Besides elemental emissions from conventional UV-Vis LIBS, molecular LIBS emission signatures of the target compounds were observed in the long-wave infrared (LWIR) region in recent studies. Most current LIBS studies employ the fundamental Nd:YAG laser output at 1.064 μm, which has extremely low eye-damage threshold. In this work, comparative LWIR-LIBS emissions studies using traditional 1.064 μm pumping and eye-safe laser wavelength at 1.574 μm were performed on several energetic materials for applications in chemical, biological, and explosive (CBE) sensing. A Q-switched Nd: YAG laser operating at 1.064 μm and the 1.574 μm output of a pulsed Nd:YAG pumped Optical Parametric Oscillator were employed as the excitation sources. The investigated energetic materials were studied for the appearance of LWIR-LIBS emissions (4-12 μm) that are directly indicative of oxygenated breakdown products as well as partially dissociated and recombination molecular species. The observed molecular IR LIBS emission bands showed strong correlation with FTIR absorption spectra of the studied materials for 1.064 μm and 1.574 μm pump wavelengths.

  20. Insensitive high-energy energetic structural material of tungsten-polytetrafluoroethylene-aluminum composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liu; Liu, Jinxu, E-mail: liujinxu@bit.edu.cn; Zhang, Xinbo [School of Material Science and Engineering, Beijing Institute of Technology, No.5 yard, Zhong Guan Cun South Street, Beijing, 100081 (China); Li, Shukui [School of Material Science and Engineering, Beijing Institute of Technology, No.5 yard, Zhong Guan Cun South Street, Beijing, 100081 (China); State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, No. 5 yard, Zhong Guan Cun South Street, Beijing 100081 (China)

    2015-11-15

    Energetic structural material is a kind of materials that are inert under normal conditions but could produce exothermic chemical reaction when subjected to impact. This report shows a kind of energetic structural material of tungsten (W)-polytetrafluoroethylene (PTFE)-aluminum (Al) with density of 4.12 g/cm{sup 3}, excellent ductility and dynamic compressive strength of 96 MPa. Moreover, 50W-35PTFE-15Al (wt%) can exhibit a high reaction energy value of more than 2 times of TNT per unit mass and 5 times of TNT per unit volume, respectively, but with excellent insensitivity compared with traditional explosives. Under thermal conditions, the W-PTFE-Al composite can keep stable at 773 K. Under impact loading, when the strain rate up to ∼4820 s{sup −1} coupled with the absorbed energy per unit volume of 120 J/cm{sup 3}, deflagration occurs and combustion lasts for 500 μs. During impact compressive deformation, the PTFE matrix is elongated into nano-fibers, thus significantly increases the reaction activity of W-PTFE-Al composites. The nano-fiber structure is necessary for the reaction of W-PTFE-Al composites. The formation of PTFE nano-fibers must undergo severe plastic deformation, and therefore the W-PTFE-Al composites exhibit excellent insensitivity and safety. Furthermore, the reaction mechanisms of W-PTFE-Al composites in argon and in air are revealed.

  1. Insensitive high-energy energetic structural material of tungsten-polytetrafluoroethylene-aluminum composites

    Directory of Open Access Journals (Sweden)

    Liu Wang

    2015-11-01

    Full Text Available Energetic structural material is a kind of materials that are inert under normal conditions but could produce exothermic chemical reaction when subjected to impact. This report shows a kind of energetic structural material of tungsten (W-polytetrafluoroethylene (PTFE-aluminum (Al with density of 4.12 g/cm3, excellent ductility and dynamic compressive strength of 96 MPa. Moreover, 50W-35PTFE-15Al (wt% can exhibit a high reaction energy value of more than 2 times of TNT per unit mass and 5 times of TNT per unit volume, respectively, but with excellent insensitivity compared with traditional explosives. Under thermal conditions, the W-PTFE-Al composite can keep stable at 773 K. Under impact loading, when the strain rate up to ∼4820 s−1 coupled with the absorbed energy per unit volume of 120 J/cm3, deflagration occurs and combustion lasts for 500 μs. During impact compressive deformation, the PTFE matrix is elongated into nano-fibers, thus significantly increases the reaction activity of W-PTFE-Al composites. The nano-fiber structure is necessary for the reaction of W-PTFE-Al composites. The formation of PTFE nano-fibers must undergo severe plastic deformation, and therefore the W-PTFE-Al composites exhibit excellent insensitivity and safety. Furthermore, the reaction mechanisms of W-PTFE-Al composites in argon and in air are revealed.

  2. Zinc-oxide-based nanostructured materials for heterostructure solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bobkov, A. A.; Maximov, A. I.; Moshnikov, V. A., E-mail: vamoshnikov@mail.ru; Somov, P. A.; Terukov, E. I. [St. Petersburg Electrotechnical University LETI (Russian Federation)

    2015-10-15

    Results obtained in the deposition of nanostructured zinc-oxide layers by hydrothermal synthesis as the basic method are presented. The possibility of controlling the structure and morphology of the layers is demonstrated. The important role of the procedure employed to form the nucleating layer is noted. The faceted hexagonal nanoprisms obtained are promising for the fabrication of solar cells based on oxide heterostructures, and aluminum-doped zinc-oxide layers with petal morphology, for the deposition of an antireflection layer. The results are compatible and promising for application in flexible electronics.

  3. Hazards Response of Energetic Materials - Initiation Mechanisms, Experimental Characterization, and Development of Predictive Capability

    Energy Technology Data Exchange (ETDEWEB)

    Maienschein, J; Nichols III, A; Reaugh, J; McClelland, M; Hsu, P C

    2005-04-15

    We present our approach to develop a predictive capability for hazards -- thermal and non-shock impact -- response of energetic material systems based on: (A) identification of relevant processes; (B) characterization of the relevant properties; (C) application of property data to predictive models; and (D) application of the models into predictive simulation. This paper focuses on the first two elements above, while a companion paper by Nichols et al focuses on the final two elements. We outline the underlying mechanisms of hazards response and their interactions, and present our experimental work to characterize the necessary material parameters, including thermal ignition, thermal and mechanical properties, fracture/fragmentation behavior, deflagration rates, and the effect of material damage. We also describe our validation test, the Scaled Thermal Explosion Experiment. Finally, we integrate the entire collection of data into a qualitative understanding that is useful until such time as the predictive models become available.

  4. MATEO: a software package for the molecular design of energetic materials.

    Science.gov (United States)

    Mathieu, Didier

    2010-04-15

    To satisfy the need of energetic materials chemists for reliable and efficient predictive tools in order to select the most promising candidates for synthesis, a custom software package is developed. Making extensive use of publicly available software, it integrates a wide range of models and can be used for a variety of tasks, from the calculation of molecular properties to the prediction of the performance of heterogeneous materials, such as propellant compositions based on ammonium perchlorate/aluminium mixtures. The package is very easy to use through a graphical desktop environment. According to the material provided as input, suitable models and parameters are automatically selected. Therefore, chemists can apply advanced predictive models without having to learn how to use complex computer codes. To make the package more versatile, a command-line interface is also provided. It facilitates the assessment of various procedures by model developers.

  5. Could Nano-Structured Materials Enable the Improved Pressure Vessels for Deep Atmospheric Probes?

    Science.gov (United States)

    Srivastava, D.; Fuentes, A.; Bienstock, B.; Arnold, J. O.

    2005-01-01

    A viewgraph presentation on the use of Nano-Structured Materials to enable pressure vessel structures for deep atmospheric probes is shown. The topics include: 1) High Temperature/Pressure in Key X-Environments; 2) The Case for Use of Nano-Structured Materials Pressure Vessel Design; 3) Carbon based Nanomaterials; 4) Nanotube production & purification; 5) Nanomechanics of Carbon Nanotubes; 6) CNT-composites: Example (Polymer); 7) Effect of Loading sequence on Composite with 8% by volume; 8) Models for Particulate Reinforced Composites; 9) Fullerene/Ti Composite for High Strength-Insulating Layer; 10) Fullerene/Epoxy Composite for High Strength-Insulating Layer; 11) Models for Continuous Fiber Reinforced Composites; 12) Tensile Strength for Discontinuous Fiber Composite; 13) Ti + SWNT Composites: Thermal/Mechanical; 14) Ti + SWNT Composites: Tensile Strength; and 15) Nano-structured Shell for Pressure Vessels.

  6. Enzymes for Degradation of Energetic Materials and Demilitarization of Explosives Stockpiles - SERDP Annual (Interim) Report, 12/98

    Energy Technology Data Exchange (ETDEWEB)

    Shah, M.M.

    1999-01-18

    The current stockpile of energetic materials requiring disposal contains about half a million tons. Through 2001, over 2.1 million tons are expected to pass through the stockpile for disposal. Safe and environmentally acceptable methods for disposing of these materials are needed. This project is developing safe, economical, and environmentally sound processes using biocatalyst (enzymes) to degrade energetic materials and to convert them into economically valuable products. Alternative methods for destroying these materials are hazardous, environmentally unacceptable, and expensive. These methods include burning, detonation, land and sea burial, treatment at high temperature and pressure, and treatment with harsh chemicals. Enzyme treatment operates at room temperature and atmospheric pressure in a water solution.

  7. Metal Nanoparticles and Carbon-Based Nanostructures as Advanced Materials for Cathode Application in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Pietro Calandra

    2010-01-01

    Full Text Available We review the most advanced methods for the fabrication of cathodes for dye-sensitized solar cells employing nanostructured materials. The attention is focused on metal nanoparticles and nanostructured carbon, among which nanotubes and graphene, whose good catalytic properties make them ideal for the development of counter electrode substrates, transparent conducting oxide, and advanced catalyst materials.

  8. Formulation and Performance of Novel Energetic Nanocomposites and Gas Generators Prepared by Sol-Gel Methods

    Energy Technology Data Exchange (ETDEWEB)

    Clapsaddle, B J; Zhao, L; Prentice, D; Pantoya, M L; Gash, A E; Satcher Jr., J H; Shea, K J; Simpson, R L

    2005-03-24

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing nanostructured metal oxide materials. By introducing a fuel metal, such as aluminum, into the nanostructured metal oxide matrix, energetic materials based on thermite reactions can be fabricated. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Due to the versatility of the preparation method, binary oxidizing phases can also be prepared, thus enabling a potential means of controlling the energetic properties of the subsequent nanocomposites. Furthermore, organic additives can also be easily introduced into the nanocomposites for the production of nanostructured gas generators. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its micro-scale counterparts due to the expected increase of mass transport rates between the reactants. The unique synthesis methodology, formulations, and performance of these materials will be presented. The degree of control over the burning rate of these nanocomposites afforded by the compositional variation of a binary oxidizing phase will also be discussed. These energetic nanocomposites have the potential for releasing controlled amounts of energy at a controlled rate. Due to the versatility of the synthesis method, a large number of compositions and physical properties can be achieved, resulting in

  9. Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test

    Energy Technology Data Exchange (ETDEWEB)

    Switzer, L L; Vandersall, K S; Chidester, S K; Greenwood, D W; Tarver, C M

    2003-07-01

    Impact tests performed at low velocity on heated energetic material samples are of interest when considering the situation of energetic materials involved in a fire. To determine heated reaction thresholds, Steven Test targets containing PBX 9404 or LX-04 samples heated to the range of 150-170 C were impacted at velocities up to 150 m/s by two different projectile head geometries. Comparing these measured thresholds to ambient temperature thresholds revealed that the heated LX-04 thresholds were considerably higher than ambient, whereas the heated PBX 9404 thresholds were only slightly higher than the ambient temperature thresholds. The violence of reaction level of the PBX 9404 was considerably higher than that of the LX-04 as measured with four overpressure gauges. The varying results in these samples with different HMX/binder configurations indicate that friction plays a dominant role in reaction ignition during impact. This work outlines the experimental details, compares the thresholds and violence levels of the heated and ambient temperature experiments, and discusses the dominant mechanisms of the measured thresholds.

  10. Laser-shocked energetic materials with metal additives: evaluation of chemistry and detonation performance.

    Science.gov (United States)

    Gottfried, Jennifer L; Bukowski, Eric J

    2017-01-20

    A focused, nanosecond-pulsed laser has been used to ablate, atomize, ionize, and excite milligram quantities of metal-doped energetic materials that undergo exothermic reactions in the laser-induced plasma. The subsequent shock wave expansion in the air above the sample has been monitored using high-speed schlieren imaging in a recently developed technique, laser-induced air shock from energetic materials (LASEM). The method enables the estimation of detonation velocities based on the measured laser-induced air-shock velocities and has previously been demonstrated for organic military explosives. Here, the LASEM technique has been extended to explosive formulations with metal additives. A comparison of the measured laser-induced air-shock velocities for TNT, RDX, DNTF, and LLM-172 doped with Al or B to the detonation velocities predicted by the thermochemical code CHEETAH for inert or active metal participation demonstrates that LASEM has potential for predicting the early time (<10  μs) participation of metal additives in detonation events. The LASEM results show that while Al is mostly inert at early times in the detonation event (confirmed from large-scale detonation testing), B is active-and reducing the amount of hydrogen present during the early chemical reactions increases the resulting estimated detonation velocities.

  11. Molecular design and performance prediction of poly-dinitroamino pyrrole compounds as energetic materials

    Indian Academy of Sciences (India)

    MEI LI; FENG-MIN WU; HANG XU

    2017-01-01

    To identify superior and safe energetic materials, eighteen poly-dinitroamino pyrrole derivatives were studied at the B3LYP/6-311G** level of density functional theory (DFT). The isodesmic reactions were employed to calculate the heats of formation (HOFs) for these compounds. The detonation velocity (D) and pressure (P) were evaluated using the Kamlet-Jacobs equations. Results indicate that –N(NO₂)₂ group is an effective substituent for enhancing the detonation performance since most of the molecules have larger energy density than RDX (1,3,5-trinitro-1,3,5-triazinane), and a few molecules, C1(N-R) - D3(N-R), with D ranging from 8.55 to 9.04 km s−1 and P ranging from 35.53 to 40.36 GPa outperform RDX (D = 8.75 km s⁻¹ and P = 34.00 GPa). The calculated bond dissociation energy (BDE) revealed that the new compounds exhibit good thermal stability and meet the requirements of energetic materials. Besides, the N-NO₂ bond on the side chain was found to be the trigger bond during decomposition. The characteristic height (h₅₀) of the compound was calculated, and thirteen compounds exhibited lower sensitivity than CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane).

  12. A Market-Basket Approach to Predict the Acute Aquatic Toxicity of Munitions and Energetic Materials.

    Science.gov (United States)

    Burgoon, Lyle D

    2016-06-01

    An ongoing challenge in chemical production, including the production of insensitive munitions and energetics, is the ability to make predictions about potential environmental hazards early in the process. To address this challenge, a quantitative structure activity relationship model was developed to predict acute fathead minnow toxicity of insensitive munitions and energetic materials. Computational predictive toxicology models like this one may be used to identify and prioritize environmentally safer materials early in their development. The developed model is based on the Apriori market-basket/frequent itemset mining approach to identify probabilistic prediction rules using chemical atom-pairs and the lethality data for 57 compounds from a fathead minnow acute toxicity assay. Lethality data were discretized into four categories based on the Globally Harmonized System of Classification and Labelling of Chemicals. Apriori identified toxicophores for categories two and three. The model classified 32 of the 57 compounds correctly, with a fivefold cross-validation classification rate of 74 %. A structure-based surrogate approach classified the remaining 25 chemicals correctly at 48 %. This result is unsurprising as these 25 chemicals were fairly unique within the larger set.

  13. The Interaction of Bacteria with Engineered Nanostructured Polymeric Materials: A Review

    Directory of Open Access Journals (Sweden)

    Ilaria Armentano

    2014-01-01

    Full Text Available Bacterial infections are a leading cause of morbidity and mortality worldwide. In spite of great advances in biomaterials research and development, a significant proportion of medical devices undergo bacterial colonization and become the target of an implant-related infection. We present a review of the two major classes of antibacterial nanostructured materials: polymeric nanocomposites and surface-engineered materials. The paper describes antibacterial effects due to the induced material properties, along with the principles of bacterial adhesion and the biofilm formation process. Methods for antimicrobial modifications of polymers using a nanocomposite approach as well as surface modification procedures are surveyed and discussed, followed by a concise examination of techniques used in estimating bacteria/material interactions. Finally, we present an outline of future sceneries and perspectives on antibacterial applications of nanostructured materials to resist or counteract implant infections.

  14. The Interaction of Bacteria with Engineered Nanostructured Polymeric Materials: A Review

    Science.gov (United States)

    Armentano, Ilaria; Arciola, Carla Renata; Fortunati, Elena; Ferrari, Davide; Mattioli, Samantha; Amoroso, Concetta Floriana; Rizzo, Jessica; Kenny, Jose M.; Imbriani, Marcello; Visai, Livia

    2014-01-01

    Bacterial infections are a leading cause of morbidity and mortality worldwide. In spite of great advances in biomaterials research and development, a significant proportion of medical devices undergo bacterial colonization and become the target of an implant-related infection. We present a review of the two major classes of antibacterial nanostructured materials: polymeric nanocomposites and surface-engineered materials. The paper describes antibacterial effects due to the induced material properties, along with the principles of bacterial adhesion and the biofilm formation process. Methods for antimicrobial modifications of polymers using a nanocomposite approach as well as surface modification procedures are surveyed and discussed, followed by a concise examination of techniques used in estimating bacteria/material interactions. Finally, we present an outline of future sceneries and perspectives on antibacterial applications of nanostructured materials to resist or counteract implant infections. PMID:25025086

  15. Novel applications exploiting the thermal properties of nanostructured materials.

    Energy Technology Data Exchange (ETDEWEB)

    Eastman, J. A.

    1998-11-20

    A new class of heat transfer fluids, termed nanofluids, has been developed by suspending nanocrystalline particles in liquids. Due to the orders-of-magnitude larger thermal conductivities of solids compared to those of liquids such as water, significantly enhanced thermal properties are obtained with nanofluids. The use of nanofluids could impact many industrial sectors, including transportation, energy supply and production, electronics, textiles, and paper production by, for example, decreasing pumping power needs or reducing heat exchanger sizes. In contrast to the enhancement in effective thermal transport rates that is obtained when nanoparticles are suspended in fluids, nanocrystalline coatings are expected to exhibit reduced thermal conductivities compared to coarse-grained coatings. Reduced thermal conductivities are predicted to arise because of a reduction in the mean free path of phonons due to presence of grain boundaries. This behavior, combined with improved mechanical properties, makes nanostructured zirconia coatings excellent candidates for future applications as thermal barriers.

  16. Nanostructured composite materials of cerium oxide and barium cerate

    Science.gov (United States)

    Medvedev, D. A.; Pikalova, E. Yu.; Demin, A. K.; Khrustov, V. R.; Nikolaenko, I. V.; Nikonov, A. V.; Malkov, V. B.; Antonov, B. D.

    2013-02-01

    Nanosized powders with a composition of (1- x)Ce0.8Sm0.2O2-δ- xBace0.8Sm0.2O3-δ ( x = 0, 0.3, and 1) were obtained by self-ignition combustion synthesis (SICS) from the appropriate nitrates and various organic fuels (glycine, glycerol, citric acid, and a mixture of citric acid and ethylene glycol). The most finely dispersed powders formed when the concentration of the perovskite phase in the system decreased or when glycerol or citric acid-enthyleneglycol mixture was used as a fuel during SICS. A procedure for the preparation of powders and nanostructured ceramics was developed and their electric properties were studied.

  17. MPS/CAS Partner Group on Nanostructured Materials

    Institute of Scientific and Technical Information of China (English)

    Lu Ke; Manfred Rühle

    2004-01-01

    @@ As one of the first Partner Groups which were initiated to foster scientific exchange and interaction between the Max Pianck Society (MPS) and the Chinese Academy of Sciences (CAS), the Partner Group led by Lu Ke was established on April 1, 1999.During the past five years, the group has received substantial support from the CAS for equipment and from the MPS for personnel and travel expenses. Extensive and productive collaborations between the research staff and students of the Partner Group with several professors (departments) in the Max Planck Institute for Metals Research (MPI-MF) have led to significant advances in synthesis,mechanical properties, melting and superheating of nanostructured metals. The research is well recognized internationally and a substantial number of publications in high quality, peer-reviewed journals (including Science and Physical Review Letters) have resulted.

  18. Development of Nanostructured Materials with Improved Radiation Tolerance for Advanced Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    Zinghang Zhang; K. Ted Hartwig

    2009-08-12

    This project will explore the fundamental mechanisms through which interfaces in nanolayered structures and grain boundaries of bulk nanomaterials are able to attract and rapidly eliminate point defects and unwanted foreign species. Candidate materials that will be studied include both nanostructured multilayer composites synthesized by magnetron sputtering and structural bulk nanomaterials produced by severed plastic deformation, equal channel angular extrusion.

  19. Electrospray-assisted synthesis methods of nanostructured materials for Li-ion batteries

    NARCIS (Netherlands)

    Valvo, M.

    2010-01-01

    This PhD thesis focuses on the synthesis of nanostructured materials via an aerosol-assisted route based on electrospraying of liquid precursors. Electrospraying is a powerful technique for the production of nearly-monodispersed, highly-charged droplets. The possibility of tailoring the droplet

  20. Electrospray-assisted synthesis methods of nanostructured materials for Li-ion batteries

    NARCIS (Netherlands)

    Valvo, M.

    2010-01-01

    This PhD thesis focuses on the synthesis of nanostructured materials via an aerosol-assisted route based on electrospraying of liquid precursors. Electrospraying is a powerful technique for the production of nearly-monodispersed, highly-charged droplets. The possibility of tailoring the droplet size

  1. Development of Nanostructured Materials with Improved Radiation Tolerance for Advanced Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    Zinghang Zhang; K. Ted Hartwig

    2009-08-12

    This project will explore the fundamental mechanisms through which interfaces in nanolayered structures and grain boundaries of bulk nanomaterials are able to attract and rapidly eliminate point defects and unwanted foreign species. Candidate materials that will be studied include both nanostructured multilayer composites synthesized by magnetron sputtering and structural bulk nanomaterials produced by severed plastic deformation, equal channel angular extrusion.

  2. High-capacity nanostructured germanium-containing materials and lithium alloys thereof

    Science.gov (United States)

    Graetz, Jason A.; Fultz, Brent T.; Ahn, Channing; Yazami, Rachid

    2010-08-24

    Electrodes comprising an alkali metal, for example, lithium, alloyed with nanostructured materials of formula Si.sub.zGe.sub.(z-1), where 0capacities, cycle lives, and/or cycling rates compared with similar electrodes made from graphite. These electrodes are useful as anodes for secondary electrochemical cells, for example, batteries and electrochemical supercapacitors.

  3. Excited electronic state decomposition mechanisms and dynamics of nitramine energetic materials and model systems

    Science.gov (United States)

    Greenfield, Margo

    Energetic materials play an important role in aeronautics, the weapon industry, and the propellant industry due to their broad applications as explosives and fuels. RDX (1,3,5-trinitrohexahydro-s-triazine), HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), and CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) are compounds which contain high energy density. Although RDX and HMX have been studied extensively over the past several decades a complete understanding of their decomposition mechanisms and dynamics is unknown. Time of flight mass spectroscopy (TOFMS) UV photodissociation (ns) experiments of gas phase RDX, HMX, and CL-20 generate the NO molecule as the initial decomposition product. Four different vibronic transitions of the initial decomposition product, the NO molecule, are observed: A2Sigma(upsilon'=0)←X 2pi(upsilon"=0,1,2,3). Simulations of the rovibronic intensities for the A←X transitions demonstrate that NO dissociated from RDX, HMX, and CL-20 is rotationally cold (˜20 K) and vibrationally hot (˜1800 K). Conversely, experiments on the five model systems (nitromethane, dimethylnitramine (DMNA), nitropyrrolidine, nitropiperidine and dinitropiperazine) produce rotationally hot and vibrationally cold spectra. Laser induced fluorescence (LIF) experiments are performed to rule out the possible decomposition product OH, generated along with NO, perhaps from the suggested HONO elimination mechanism. The OH radical is not observed in the fluorescence experiments, indicating the HONO decomposition intermediate is not an important pathway for the excited electronic state decomposition of cyclic nitramines. The NO molecule is also employed to measure the dynamics of the excited state decomposition. A 226 nm, 180 fs light pulse is utilized to photodissociate the gas phase systems. Stable ion states of DMNA and nitropyrrolidine are observed while the energetic materials and remaining model systems present the NO molecule as the only

  4. Recent advances in multistep solution nanosynthesis of nanostructured three-dimensional complexes of semiconductive materials

    Institute of Scientific and Technical Information of China (English)

    Huajun Zhou; Z. Ryan Tian

    2013-01-01

    Constructing simply nanostructured zero-, one-, and two-dimensional crystallites into three-dimensional multifunctional assemblies and systems at low-cost is essential and highly challenging in materials science and engineering. Compared to the simply nanostructured components, a three-dimensional (3D) complex made with a precisely controlled spatial organization of all structural nanocomponents can enable us to concert functionalities from all the nanocomponents. Methodologically, so doing in nm-scales via a solution chemistry route may be much easier and less expensive than via other mechanisms. Hence, we discuss herein some recent advances in multistep solution syntheses of nanostructured 3D complexes of semiconductors with a focus mainly on their synthetic strategies and detailed mechanisms.

  5. Nanostructured material surfaces--preparation, effect on cellular behavior, and potential biomedical applications: a review.

    Science.gov (United States)

    Guduru, Deepak; Niepel, Marcus; Vogel, Jürgen; Groth, Thomas

    2011-10-01

    Nanostructures play important roles in vivo, where nanoscaled features of extracellular matrix (ECM) components influence cell behavior and resultant tissue formation. This review summarizes some of the recent developments in fostering new concepts and approaches to nanofabrication, such as top-down and bottom-up and combinations of the two. As in vitro investigations demonstrate that man-made nanotopography can be used to control cell reactions to a material surface, its potential application in implant design and tissue engineering becomes increasingly evident. Therefore, we present recent progress in directing cell fate in the field of cell mechanics, which has grown rapidly over the last few years, and in various tissue-engineering applications. The main focus is on the initial responses of cells to nanostructured surfaces and subsequent influences on cellular functions. Specific examples are also given to illustrate the potential nanostructures may have for biomedical applications and regenerative medicine.

  6. Precursor Mediated Synthesis of Nanostructured Silicas: From Precursor-Surfactant Ion Pairs to Structured Materials

    Directory of Open Access Journals (Sweden)

    Peter Hesemann

    2014-04-01

    Full Text Available The synthesis of nanostructured anionic-surfactant-templated mesoporous silica (AMS recently appeared as a new strategy for the formation of nanostructured silica based materials. This method is based on the use of anionic surfactants together with a co-structure-directing agent (CSDA, mostly a silylated ammonium precursor. The presence of this CSDA is necessary in order to create ionic interactions between template and silica forming phases and to ensure sufficient affinity between the two phases. This synthetic strategy was for the first time applied in view of the synthesis of surface functionalized silica bearing ammonium groups and was then extended on the formation of materials functionalized with anionic carboxylate and bifunctional amine-carboxylate groups. In the field of silica hybrid materials, the “anionic templating” strategy has recently been applied for the synthesis of silica hybrid materials from cationic precursors. Starting from di- or oligosilylated imidazolium and ammonium precursors, only template directed hydrolysis-polycondensation reactions involving complementary anionic surfactants allowed accessing structured ionosilica hybrid materials. The mechanistic particularity of this approach resides in the formation of precursor-surfactant ion pairs in the hydrolysis-polycondensation mixture. This review gives a systematic overview over the various types of materials accessed from this cooperative ionic templating approach and highlights the high potential of this original strategy for the formation of nanostructured silica based materials which appears as a complementary strategy to conventional soft templating approaches.

  7. A review of nanostructured lithium ion battery materials via low temperature synthesis.

    Science.gov (United States)

    Chen, Jiajun

    2013-01-01

    Nanostructured materials afford us new opportunities to improve the current technology for synthesizing Li ion batteries. Generating nanomaterials with new properties via an inexpensive approach offers a tremendous potential for realizing high performance Li-ion batteries. In this review, I mainly summarize some of the recent progress made, and describe the patents awarded on synthesizing nanostructured cathode materials for these batteries via low temperature wet- chemistry methods. From an economical view, such syntheses, especially hydrothermal synthesis, may offer the opportunities for significantly lowering the cost of manufacturing battery materials, while conferring distinct environmental advantages. Recent advances in in-situ (real time) X-ray diffraction for studying hydrothermal synthesis have great potential for bettering the rational design of advanced lithium-electrode materials. The development of this technique also will be discussed.

  8. Effect of energetic materials wettability on their outdoor effective elution rate.

    Science.gov (United States)

    Lapointe, Marie-Claude; Martel, Richard; Lange, Sébastien F; Coté, Sébastien

    2016-07-05

    Energetic materials (EM) contained in military ammunitions have been found in the surface soil and water of training areas and may potentially represent a threat to human health and the environment. EM wettability is an essential physical parameter to characterize because it controls EM dissolution rate. This paper was conducted to determine the wettability of conventional and new EM formulations used in military ammunition. Wettability was estimated in the laboratory via contact angle measurements of water droplets on different EM surfaces. Results show that 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), Octol and energetic thermoplastic elastomer (ETPE) 1000 are hydrophilic while Composition B, XRT, GIM, CX-85, ETPE 2000, and C4 are hydrophobic whereas HELOVA gun propellant has a mixed wettability oscillating between hydrophilic and hydrophobic. The present study demonstrates that wettability of EM formulation is generally controlled by their matrix constituents. Results indicate that hydrophobic formulations have a much slower outdoor environmental effective elution rate than hydrophilic ones, with the exception of the hydrophobic C4 formulation whose elution rate is extremely high. The addition of hydrophobic components into EM formulations is recommended to diminish the environmental impact on water, as it has already been done with XRT, GIM and CX-85 formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. From FOX-7 to H-FOX to insensitive energetic materials with hypergolic properties.

    Science.gov (United States)

    Srinivas, Dharavath; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

    2016-06-08

    Nitrogen/halogen rich derivatives, , , , and of FOX-7 (1,1-diamino-2,2-dinitroethene), and H-FOX (1-hydrazinyl-2,2-dinitroethenamine) have been synthesized, characterized and found to exhibit good energetic properties. Compound displays hypergolic properties with commonly utilized fuels such as monomethyl hydrazine (MMH), and hydrazine hydrate (HH), as well as with ethylenediamine (EN), and 1,3-diaminopropane (DAP) showing ignition delay times between 2.5 to 10 ms. Additionally, the hypergolic properties of 4 and 8 were further studied by using ammonia borane as a fuel solubilized in a green ionic liquid, 1-allyl-3-methyl imidazolium dicyanamide, (1 : 1 molar ratio). This is a new role for a derivative of H-FOX. The energetic and physical properties of all the molecules were either measured or calculated. All of materials were characterized by NMR, and infrared spectra, elemental analyses, and differential scanning calorimetry. Single crystal X-ray structural measurements for and were helpful in their confirmation.

  10. Quantifying protein adsorption and function at nanostructured materials: enzymatic activity of glucose oxidase at GLAD structured electrodes.

    Science.gov (United States)

    Jensen, Uffe B; Ferapontova, Elena E; Sutherland, Duncan S

    2012-07-31

    Nanostructured materials strongly modulate the behavior of adsorbed proteins; however, the characterization of such interactions is challenging. Here we present a novel method combining protein adsorption studies at nanostructured quartz crystal microbalance sensor surfaces (QCM-D) with optical (surface plasmon resonance SPR) and electrochemical methods (cyclic voltammetry CV) allowing quantification of both bound protein amount and activity. The redox enzyme glucose oxidase is studied as a model system to explore alterations in protein functional behavior caused by adsorption onto flat and nanostructured surfaces. This enzyme and such materials interactions are relevant for biosensor applications. Novel nanostructured gold electrode surfaces with controlled curvature were fabricated using colloidal lithography and glancing angle deposition (GLAD). The adsorption of enzyme to nanostructured interfaces was found to be significantly larger compared to flat interfaces even after normalization for the increased surface area, and no substantial desorption was observed within 24 h. A decreased enzymatic activity was observed over the same period of time, which indicates a slow conformational change of the adsorbed enzyme induced by the materials interface. Additionally, we make use of inherent localized surface plasmon resonances in these nanostructured materials to directly quantify the protein binding. We hereby demonstrate a QCM-D-based methodology to quantify protein binding at complex nanostructured materials. Our approach allows label free quantification of protein binding at nanostructured interfaces.

  11. Nanostructured titanium-based materials for medical implants: Modeling and development

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Levashov, Evgeny; Valiev, Ruslan Z.

    2014-01-01

    . Computational methods of nanostructure properties simulation and various approaches to the computational, "virtual" testing and numerical optimization of these materials are discussed. Applications of atomistic methods, continuum micromechanics and crystal plasticity as well as analytical models to the analysis...... of the reserves of the improvement of materials for medical implants are demonstrated. Examples of successful development of a nanomaterial-based medical implants are presented. (C) 2014 Elsevier B.V. All rights reserved....

  12. N-oxide 1,2,4,5-tetrazine-based high-performance energetic materials.

    Science.gov (United States)

    Wei, Hao; Gao, Haixiang; Shreeve, Jean'ne M

    2014-12-15

    One route to high density and high performance energetic materials based on 1,2,4,5-tetrazine is the introduction of 2,4-di-N-oxide functionalities. Based on several examples and through theoretical analysis, the strategy of regioselective introduction of these moieties into 1,2,4,5-tetrazines has been developed. Using this methodology, various new tetrazine structures containing the N-oxide functionality were synthesized and fully characterized using IR, NMR, and mass spectroscopy, elemental analysis, and single-crystal X-ray analysis. Hydrogen peroxide (50 %) was used very effectively in lieu of the usual 90 % peroxide in this system to generate N-oxide tetrazine compounds successfully. Comparison of the experimental densities of N-oxide 1,2,4,5-tetrazine compounds with their 1,2,4,5-tetrazine precursors shows that introducing the N-oxide functionality is a highly effective and feasible method to enhance the density of these materials. The heats of formation for all compounds were calculated with Gaussian 03 (revision D.01) and these values were combined with measured densities to calculate detonation pressures (P) and velocities (νD ) of these energetic materials (Explo 5.0 v. 6.01). The new oxygen-containing tetrazines exhibit high density, good thermal stability, acceptable oxygen balance, positive heat of formation, and excellent detonation properties, which, in some cases, are superior to those of 1,3,5-tritnitrotoluene (TNT), 1,3,5-trinitrotriazacyclohexane (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Recent advances in the molten salt technology for the destruction of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Upadhye, R.S.; Watkins, B.E.; Pruneda, C.O.

    1995-11-01

    The DOE has thousands of pounds of energetic materials which result from dismantlement operations at the Pantex Plant. The authors have demonstrated the Molten Salt Destruction (MSD) Process for the treatment of explosives and explosive-containing wastes on a 1.5 kilogram of explosive per hour scale and are currently building a 5 kilogram per hour unit. MSD converts the organic constituents of the waste into non-hazardous substances such as carbon dioxide, nitrogen and water. Any inorganic constituents of the waste, such as binders and metallic particles, are retained in the molten salt. The destruction of energetic material waste is accomplished by introducing it, together with air, into a crucible containing a molten salt, in this case a eutectic mixture of Na, K, and Li carbonates. The following pure component DOE and DoD explosives have been destroyed in LLNL`s experimental unit at their High Explosives Applications Facility (HEAF): ammonium picrate, HMX, K-6, NQ, NTO, PETN, RDX, TATB, and TNT. In addition, the following formulations were also destroyed: Comp B, LX-10, LX-16, LX-17, PBX-9404, and XM46, a US Army liquid gun propellant. In this 1.5 kg/hr unit, the fractions of carbon converted to CO and of chemically bound nitrogen converted to NOx were found to be well below 1T. In addition to destroying explosive powders and molding powders the authors have also destroyed materials that are typical of real world wastes. These include shavings from machined pressed parts of plastic bonded explosives and sump waste containing both explosives and non-explosive debris. Based on the information obtained on the smaller unit, the authors have constructed a 5 kg/hr MSD unit, incorporating LLNL`s advanced chimney design. This unit is currently under shakedown tests and evaluation.

  14. Large-Scale Reactive Atomistic Simulation of Shock-induced Initiation Processes in Energetic Materials

    Science.gov (United States)

    Thompson, Aidan

    2013-06-01

    Initiation in energetic materials is fundamentally dependent on the interaction between a host of complex chemical and mechanical processes, occurring on scales ranging from intramolecular vibrations through molecular crystal plasticity up to hydrodynamic phenomena at the mesoscale. A variety of methods (e.g. quantum electronic structure methods (QM), non-reactive classical molecular dynamics (MD), mesoscopic continuum mechanics) exist to study processes occurring on each of these scales in isolation, but cannot describe how these processes interact with each other. In contrast, the ReaxFF reactive force field, implemented in the LAMMPS parallel MD code, allows us to routinely perform multimillion-atom reactive MD simulations of shock-induced initiation in a variety of energetic materials. This is done either by explicitly driving a shock-wave through the structure (NEMD) or by imposing thermodynamic constraints on the collective dynamics of the simulation cell e.g. using the Multiscale Shock Technique (MSST). These MD simulations allow us to directly observe how energy is transferred from the shockwave into other processes, including intramolecular vibrational modes, plastic deformation of the crystal, and hydrodynamic jetting at interfaces. These processes in turn cause thermal excitation of chemical bonds leading to initial chemical reactions, and ultimately to exothermic formation of product species. Results will be presented on the application of this approach to several important energetic materials, including pentaerythritol tetranitrate (PETN) and ammonium nitrate/fuel oil (ANFO). In both cases, we validate the ReaxFF parameterizations against QM and experimental data. For PETN, we observe initiation occurring via different chemical pathways, depending on the shock direction. For PETN containing spherical voids, we observe enhanced sensitivity due to jetting, void collapse, and hotspot formation, with sensitivity increasing with void size. For ANFO, we

  15. Review on recent progress of nanostructured anode materials for Li-ion batteries

    KAUST Repository

    Goriparti, Subrahmanyam

    2014-07-01

    This review highlights the recent research advances in active nanostructured anode materials for the next generation of Li-ion batteries (LIBs). In fact, in order to address both energy and power demands of secondary LIBs for future energy storage applications, it is required the development of innovative kinds of electrodes. Nanostructured materials based on carbon, metal/semiconductor, metal oxides and metal phosphides/nitrides/sulfides show a variety of admirable properties for LIBs applications such as high surface area, low diffusion distance, high electrical and ionic conductivity. Therefore, nanosized active materials are extremely promising for bridging the gap towards the realization of the next generation of LIBs with high reversible capacities, increased power capability, long cycling stability and free from safety concerns. In this review, anode materials are classified, depending on their electrochemical reaction with lithium, into three groups: intercalation/de-intercalation, alloy/de-alloy and conversion materials. Furthermore, the effect of nanoscale size and morphology on the electrochemical performance is presented. Synthesis of the nanostructures, lithium battery performance and electrode reaction mechanisms are also discussed. To conclude, the main aim of this review is to provide an organic outline of the wide range of recent research progresses and perspectives on nanosized active anode materials for future LIBs.

  16. Combustion of porous energetic materials in the merged-flame regime

    Energy Technology Data Exchange (ETDEWEB)

    Margolis, S.B. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Williams, F.A.; Telengator, A.M. [Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Applied Mechanics and Engineering Sciences

    1996-02-01

    The structure and burning rate of an unconfined deflagration propagating through a porous energetic material is analyzed in the limit of merged condensed and gas-phase reaction zones. A global two-step reaction mechanism, applicable to certain types of degraded nitramine propellants and consisting of sequential condensed and gaseous steps, is postulated. Taking into account important effects due to multiphase flow and exploiting the limit of large activation energies, a theoretical analysis based on activation energy asymptotics leads to explicit formulas for the deflagration velocity in a specifically identified regime that is consistent with the merged-flame assumption. The results clearly indicate the influences of two-phase flow and the multiphase, multi-step chemistry on the deflagration structure and the burning rate, and define conditions that support the intrusion of the primary gas flame into the two-phase condensed decomposition region at the propellant surface.

  17. The thermochemistry and reaction mechanisms in the decomposition of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Melius, C.F.

    1994-05-01

    The chemical processes involved in the decomposition of energetic materials have been investigated theoretically using quantum chemical methods to determine the thermochemistry and reaction pathways. The Bond-Additivity-Corrected Moller-Plesset 4th order perturbation theory method (BAC-MP4) has been used to determine heats of formation and free energies of reaction intermediates of decomposition. In addition, the BAC-MP4 method has been used to determine action pathways involving these intermediates. A theoretical method for calculating solvation energies has been developed to treat the non-idealities of high pressure and the condensed phase. The resulting chemical processes involving decomposition and ignition are presented for nitrate compounds, nitramines, and nitromethane.

  18. Efficient Synthesis of Primary Nitrocarbamates of Sugar Alcohols: From Food to Energetic Materials.

    Science.gov (United States)

    Axthammer, Quirin J; Klapötke, Thomas M; Krumm, Burkhard

    2016-02-18

    The synthesis of various new polyvalent nitrocarbamates derived from sugar alcohols was accomplished by an economically benign two-step synthesis. The precursor carbamates were synthesized with the reagent chlorosulfonyl isocyanate (CSI) and further nitrated using mixed acid. The starting materials, sugar alcohols, are renewable biomass, mainly used in food and cosmetic industry. The structures of one carbamate and one nitrocarbamate were exemplary described by single-crystal X-ray-analysis. The heat of formation is calculated by the use of isodesmic reactions and the energetic performance data were estimated. All compounds were fully characterized by elemental analysis, vibrational spectroscopy, (1)H, (13)C, and (14/15)N NMR spectroscopy and thermal analysis (DSC). The nitrocarbamates exhibit good detonation performance and have significantly lower sensitivities compared to the commonly used nitrate ester explosive PETN.

  19. Propagation of combustion waves in the shell-core energetic materials with external heat losses.

    Science.gov (United States)

    Gubernov, V V; Kudryumov, V N; Kolobov, A V; Polezhaev, A A

    2017-03-01

    In this paper, the properties and stability of combustion waves propagating in the composite solid energetic material of the shell-core type are numerically investigated within the one-dimensional diffusive-thermal model with heat losses to the surroundings. The flame speed is calculated as a function of the parameters of the model. The boundaries of stability are determined in the space of parameters by solving the linear stability problem and direct integration of the governing non-stationary equations. The results are compared with the characteristics of the combustion waves in pure solid fuel. It is demonstrated that a stable travelling combustion wave solution can exist for the parameters of the model for which the flame front propagation is unstable in pure solid fuel and it can propagate several times faster even in the presence of significant heat losses.

  20. Investigations on deflagration to detonation transition in porous energetic materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, D.S. [Univ. of Illinois, Urbana, IL (United States)

    1999-07-01

    The research carried out by this contract was part of a larger effort funded by LANL in the areas of deflagration to detonation in porous energetic materials (DDT) and detonation shock dynamics in high explosives (DSD). In the first three years of the contract the major focus was on DDT. However, some researchers were carried out on DSD theory and numerical implementation. In the last two years the principal focus of the contract was on DSD theory and numerical implementation. However, during the second period some work was also carried out on DDT. The paper discusses DDT modeling and DSD modeling. Abstracts are included on the following topics: modeling deflagration to detonation; DSD theory; DSD wave front tracking; and DSD program burn implementation.

  1. Application of simultaneous thermogravimetric modulated beam mass spectrometry to the study of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, R. Jr. [Sandia National Labs., Livermore, CA (United States)

    1995-03-01

    Simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) and time-of-flight velocity (TOF) spectra have been developed to study reactions that occur during the thermal decomposition of liquids and solids. The data obtained with these techniques are the identity of the reaction products and their rates of gas formation as a function of time. Over the past several years, these techniques have been applied to the study of energetic materials that are used in propellants and explosives. In this presentation, the details of the STMBMS and TOF velocity spectra techniques will be reviewed, the advantages of the techniques over more conventional thermal analysis and mass spectrometry measurements will be discussed, and the use of the techniques will be illustrated with results on the thermal decomposition of hexahydro-1,3,5-s-triazine (RDX).

  2. Pressure Dependent Decomposition Kinetics of the Energetic Material HMX up to 3.6 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Glascoe, E A; Zaug, J M; Burnham, A K

    2009-05-29

    The effect of pressure on the thermal decomposition rate of the energetic material HMX was studied. HMX was precompressed in a diamond anvil cell (DAC) and heated at various rates. The parent species population was monitored as a function of time and temperature using Fourier transform infrared (FTIR) spectroscopy. Decomposition rates were determined by fitting the fraction reacted to the extended-Prout-Tompkins nucleation-growth model and the Friedman isoconversional method. The results of these experiments and analysis indicate that pressure accelerates the decomposition at low to moderate pressures (i.e. between ambient pressure and 1 GPa) and decelerates the decomposition at higher pressures. The decomposition acceleration is attributed to pressure enhanced autocatalysis whereas the deceleration at high pressures is attributed pressure inhibiting bond homolysis step(s), which would result in an increase in volume. These results indicate that both {beta} and {delta} phase HMX are sensitive to pressure in the thermally induced decomposition kinetics.

  3. Tungsten bridge for the low energy ignition of explosive and energetic materials

    Science.gov (United States)

    Benson, David A.; Bickes, Jr., Robert W.; Blewer, Robert S.

    1990-01-01

    A tungsten bridge device for the low energy ignition of explosive and energetic materials is disclosed. The device is fabricated on a silicon-on-sapphire substrate which has an insulating bridge element defined therein using standard integrated circuit fabrication techniques. Then, a thin layer of tungsten is selectively deposited on the silicon bridge layer using chemical vapor deposition techniques. Finally, conductive lands are deposited on each end of the tungsten bridge layer to form the device. It has been found that this device exhibits substantially shorter ignition times than standard metal bridges and foil igniting devices. In addition, substantially less energy is required to cause ignition of the tungsten bridge device of the present invention than is required for common metal bridges and foil devices used for the same purpose.

  4. Computational investigation of the properties of double furazan-based and furoxan-based energetic materials.

    Science.gov (United States)

    Xia, Mingzhu; Chu, Yuting; Wang, Tianyi; Lei, Wu; Wang, Fengyun

    2016-11-01

    As a kind of promising energetic materials, the double furazan-based and furoxan-based compounds have raised concerns of many researchers in recent years. In this paper, the optimized structures, energetic properties, heat of formation (HOF), detonation properties, and bond dissociation energies of these compounds were calculated by density functional theory (DFT) method. The results show that the N-O bond, which is close to the adjacent coordinated oxygen atom in furoxan ring, is more fragile than the other N-O bonds in the ring. The double furazan-based derivatives are more stable than the double furoxan-based derivatives. All the titled compounds are divided into five groups because of the different substitute groups on both ends. The HOFs of the substances offer the order of 4 group (the both ends are 1,2,3,4-tetrazine ) ≈ 5 group (1,2,4,5-tetrazine) > 3 group (tetrazole) ≈ 1 group (1,2,3-triazole) > 2 group (1,2,4-triazole). All the title compounds also can be divided into three types with the different linkages, -N=N-, -N=N(O)-, and -NH-NH-. The results show that the HOFs of the compounds with different linkages obey the order -N=N- type > -N=N(O)- type> -NH-NH- type. For all titled compounds, bis(4-(1,2,4,5-tetrazin-3-yl)-1,2,5-oxadiazol-3-yl) diazene (E5) has the best gas-phase and solid-phase HOFs. The heat of detonation(Q) of bis(3-(1,2,3,4-tetrazin-5-yl)-1,2,5-oxidiazole-2 -oxide)diazene-1,2-diyl (B4) is the best of all titled compounds. The density of bis((3-2H-tetrazol-5-yl)-1,2,5-oxidiazole -2-oxide)oxidodiazene-1,2-diyl (A3) is the best and the second best is bis((4-2H-tetrazol-5-yl)-1,2,5-oxidiazol-3-yl) diazene (E3). The detonation velocities and detonation pressure of A3 and E3 are better than other titled compounds. 1,2-bis((4-2H-tetrazol-5-yl)-1,2,5 -oxidiazol-3-yl) diazene-1-oxide (D3) and 1,2-bis((4-2H-tetrazol-5-yl)-1,2,5-oxidiazol-3-yl) hydrazine (F3) have superior D and P with low sensitivity. The tetrazole ring plays a vital role in

  5. Micro- and Nanoscale Energetic Materials as Effective Heat Energy Sources for Enhanced Gas Generators.

    Science.gov (United States)

    Kim, Sang Beom; Kim, Kyung Ju; Cho, Myung Hoon; Kim, Ji Hoon; Kim, Kyung Tae; Kim, Soo Hyung

    2016-04-13

    In this study, we systematically investigated the effect of micro- and nanoscale energetic materials in formulations of aluminum microparticles (Al MPs; heat source)/aluminum nanoparticles (Al NPs; heat source)/copper oxide nanoparticles (CuO NPs; oxidizer) on the combustion and gas-generating properties of sodium azide microparticles (NaN3 MPs; gas-generating agent) for potential applications in gas generators. The burn rate of the NaN3 MP/CuO NP composite powder was only ∼0.3 m/s. However, the addition of Al MPs and Al NPs to the NaN3 MP/CuO NP matrix caused the rates to reach ∼1.5 and ∼5.3 m/s, respectively. In addition, the N2 gas volume flow rate generated by the ignition of the NaN3 MP/CuO NP composite powder was only ∼0.6 L/s, which was significantly increased to ∼1.4 and ∼3.9 L/s by adding Al MPs and Al NPs, respectively, to the NaN3 MP/CuO NP composite powder. This suggested that the highly reactive Al MPs and NPs, with the assistance of CuO NPs, were effective heat-generating sources enabling the complete thermal decomposition of NaN3 MPs upon ignition. Al NPs were more effective than Al MPs in the gas generators because of the increased reactivity induced by the reduced particle size. Finally, we successfully demonstrated that a homemade airbag with a specific volume of ∼140 mL could be rapidly and fully inflated by the thermal activation of nanoscale energetic material-added gas-generating agents (i.e., NaN3 MP/Al NP/CuO NP composites) within the standard time of ∼50 ms for airbag inflation.

  6. RNA as a stable polymer to build controllable and defined nanostructures for material and biomedical applications.

    Science.gov (United States)

    Li, Hui; Lee, Taek; Dziubla, Thomas; Pi, Fengmei; Guo, Sijin; Xu, Jing; Li, Chan; Haque, Farzin; Liang, Xing-Jie; Guo, Peixuan

    2015-10-01

    The value of polymers is manifested in their vital use as building blocks in material and life sciences. Ribonucleic acid (RNA) is a polynucleic acid, but its polymeric nature in materials and technological applications is often overlooked due to an impression that RNA is seemingly unstable. Recent findings that certain modifications can make RNA resistant to RNase degradation while retaining its authentic folding property and biological function, and the discovery of ultra-thermostable RNA motifs have adequately addressed the concerns of RNA unstability. RNA can serve as a unique polymeric material to build varieties of nanostructures including nanoparticles, polygons, arrays, bundles, membrane, and microsponges that have potential applications in biomedical and material sciences. Since 2005, more than a thousand publications on RNA nanostructures have been published in diverse fields, indicating a remarkable increase of interest in the emerging field of RNA nanotechnology. In this review, we aim to: delineate the physical and chemical properties of polymers that can be applied to RNA; introduce the unique properties of RNA as a polymer; review the current methods for the construction of RNA nanostructures; describe its applications in material, biomedical and computer sciences; and, discuss the challenges and future prospects in this field.

  7. [The application of the nanostructured bioplastic material for the plastic reconstruction of perforations in the nasal septum].

    Science.gov (United States)

    Grigor'eva, M V; Akimov, A V; Bagautdinov, A A

    2014-01-01

    The objective of the present work was to estimate the effectiveness of the application of the nanostructured bioplastic material for the plastic reconstruction of perforations in the nasal septum. A total of 80 patients were recruited for the study. Half of them underwent plastic reconstruction of perforations in the nasal septum with the application of the nanostructured bioplastic material. Forty patients were treated using no biotransplants. The functional state of nasal cavity mucosa was evaluated before and after surgery. It is concluded that the nanostructured bioplastic material used in the present study ensures efficacious reconstruction of nasal septum integrity after plastic correction of septal perforations.

  8. EOS determination through microscopy- interferometry measurements: A low symmetry energetic materials case study

    Science.gov (United States)

    Stavrou, Elissaios; Zaug, Joseph; Crowhurst, Jonathan; Bastea, Sorin; Armstrong, Mike

    2015-03-01

    Measuring equation of state (EOS) of solid specimens under pressure usually involves the determination of the primitive cell volume using x-ray diffraction (XRD) measurements. However, in the case of low symmetry (e.g. triclinic) materials with twining features and large primitive cells, this can be problematic and ambiguous. In order to address this issue we examine the possibility of a direct approach which is based on measuring the surface area and thickness with microscopy and optical interferometry respectively. To test the validity of this approach applied to a crystalline material, we first compared our results from Triamino-Trinitrobenzene (TATB, SG P-1) with the published EOS, as determined with XRD measurements, by Stevens et al. [1]. A near perfect match between the two sets of data has been observed. We also present the results of our study on the energetic material 5-nitro-2,4-dihydro-1,2,4,-triazol-3-one (a-NTO) which crystallizes as a four-component twin [2] with triclinic symmetry. No high-pressure XRD data have been published on a-NTO, probably due to its highly complex crystal structure, making this technique a viable way to probe the cold compression EOS of such compounds. Work performed by the U.S. Department of Energy jointly by Lawrence Livermore National Laboratory; Contract DE-AC52-07NA27344.

  9. Experimental and Numerical Investigations of Thermal Ignition of a Phase Changing Energetic Material

    Directory of Open Access Journals (Sweden)

    Priyanka Shukla

    2016-04-01

    Full Text Available Fortuitous exposure to high temperatures initiates reaction in energetic materials and possibilities of such event are of great concern in terms of the safe and controlled usage of explosive devices. Experimental and numerical investigations on time to explosion and location of ignition of a phase changing polymer bonded explosive material (80 per cent RDX and 20 per cent binder, contained in a metallic confinement subjected to controlled temperature build-up on its surface, are presented. An experimental setup was developed in which the polymer bonded explosive material filled in a cylindrical confinement was provided with a precise control of surface heating rate. Temperature at various radial locations was monitored till ignition. A computational model for solving two dimensional unsteady heat transfer with phase change and heat generation due to multi-step chemical reaction was developed. This model was implemented using a custom field function in the framework of a finite volume method based standard commercial solver. Numerical study could simulate the transient heat conduction, the melting pattern of the explosive within the charge and also the thermal runaway. Computed values of temperature evolution at various radial locations and the time to ignition were closely agreeing with those measured in experiment. Results are helpful both in predicting the possibility of thermal ignition during accidents as well as for the design of safety systems.

  10. Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development.

    Energy Technology Data Exchange (ETDEWEB)

    Kearney, Sean Patrick; Jilek, Brook Anton; Kohl, Ian Thomas; Farrow, Darcie; Urayama, Junji

    2014-11-01

    We present the results of an LDRD project to develop diagnostics to perform fundamental measurements of material properties during shock compression of condensed phase materials at micron spatial scales and picosecond time scales. The report is structured into three main chapters, which each focus on a different diagnostic devel opment effort. Direct picosecond laser drive is used to introduce shock waves into thin films of energetic and inert materials. The resulting laser - driven shock properties are probed via Ultrafast Time Domain Interferometry (UTDI), which can additionally be used to generate shock Hugoniot data in tabletop experiments. Stimulated Raman scattering (SRS) is developed as a temperature diagnostic. A transient absorption spectroscopy setup has been developed to probe shock - induced changes during shock compressio n. UTDI results are presented under dynamic, direct - laser - drive conditions and shock Hugoniots are estimated for inert polystyrene samples and for the explosive hexanitroazobenzene, with results from both Sandia and Lawrence Livermore presented here. SRS a nd transient absorption diagnostics are demonstrated on static thin - film samples, and paths forward to dynamic experiments are presented.

  11. Fabrication of a nanostructured gold-polymer composite material.

    Science.gov (United States)

    Mallick, K; Witcomb, M; Scurrell, M

    2006-07-01

    A facile synthesis route is described for the preparation of a poly-(o-aminophenol)-gold nanoparticle composite material by polymerization of o-aminophenol (AP) monomer using HAuCl(4) as the oxidant. The synthesis was carried out in a methanol medium so that it could serve a dual solvent role, a solvent for both the AP and the water solution of HAuCl(4). It was found that oxidative polymerization of AP leads to the formation of poly-AP with a diameter of 50+/-10nm, while the reduction of AuCl(4) (-) results in the formation of gold nanoparticles ( approximately 2nm). The gold nanoparticles were uniformly dispersed and highly stabilized throughout the macromolecular chain that formed a uniform metal-polymer composite material. The resultant composite material was characterized by means of different techniques, such as UV-vis, IR and Raman spectroscopy, which offered the information about the chemical structure of polymer, whereas electron microscopy images provided information regarding the morphology of the composite material and the distribution of the metal particles in the composite material.

  12. Synthesis and characterization of large specific surface area nanostructured amorphous silica materials.

    Science.gov (United States)

    Marquez-Linares, Francisco; Roque-Malherbe, Rolando M A

    2006-04-01

    Large specific surface area materials attract wide attention because of their applications in adsorption, catalysis, and nanotechnology. In the present study, we describe the synthesis and characterization of nanostructured amorphous silica materials. These materials were obtained by means of a modification of the Stobe-Fink-Bohn (SFB) method. The morphology and essential features of the synthesized materials have been studied using an automated surface area and pore size analyzer and scanning electron microscopy. The existence of a micro/mesoporous structure in the obtained materials has been established. It was also found that the obtained particle packing materials show large specific surface area up to 1,600 m2/g. (To our best knowledge, there is no any reported amorphous silica material with such a higher specific surface area.) The obtained materials could be useful in the manufacture of adsorbents, catalyst supports, and other nanotechnological applications.

  13. Nanostructured silicon for photonics from materials to devices

    CERN Document Server

    Gaburro, Z; Daldosso, N

    2006-01-01

    The use of light to channel signals around electronic chips could solve several current problems in microelectronic evolution including: power dissipation, interconnect bottlenecks, input/output from/to optical communication channels, poor signal bandwidth, etc. It is unfortunate that silicon is not a good photonic material: it has a poor light-emission efficiency and exhibits a negligible electro-optical effect. Silicon photonics is a field having the objective of improving the physical properties of silicon; thus turning it into a photonic material and permitting the full convergence of elec

  14. Thermal radiative properties of metamaterials and other nanostructured materials: A review

    Institute of Scientific and Technical Information of China (English)

    Ceji FU; Zhuomin M. ZHANG

    2009-01-01

    The ability to manufacture, control, and manipulate structures at extremely small scales is the hallmark of modem technologies, including microelec-tronics, MEMS/NEMS, and nano-biotechnology. Along with the advancement of microfabrication technology, more and more investigations have been performed in recent years to understand the influence of microstructures on radiative properties. The key to the enhancement of performance is through the modification of the reflection and transmission properties of electromagnetic waves and thermal emission spectra using one-, two-, or three-dimensional micro/nanostructures. This review focuses on recent developments in metamaterials-manmade mate-rials with exotic optical properties, and other nanostruc-tured materials, such as gratings and photonic crystals, for application in radiative energy transfer and energy conversion systems.

  15. In situ neutron scattering study of nanostructured PbTe-PbS bulk thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Fei [Temple University; Schmidt, Robert D [ORNL; Case, Eldon D [Michigan State University, East Lansing; An, Ke [ORNL

    2016-01-01

    Nanostructures play an important role in thermoelectric materials. Their thermal stability, such as phase change and evolution at elevated temperatures, is thus of great interest to the thermoelectric community. In this study, in situ neutron diffraction was used to examine the phase evolution of nanostructured bulk PbTe-PbS materials fabricated using hot pressing and pulsed electrical current sintering (PECS). The PbS second phase was observed in all samples in the as-pressed condition. The temperature dependent lattice parameter and phase composition data show an initial formation of PbS precipitates followed by a redissolution during heating. The redissolution process started around 570 600 K, and completed at approximately 780 K. During cooling, the PECS sample followed a reversible curve while the heating/cooling behavior of the hot pressed sample was irreversible.

  16. Asymmetrically substituted 5,5 `-bistriazoles - nitrogen-rich materials with various energetic functionalities

    OpenAIRE

    Dippold, Alexander A.; Klapötke, Thomas M.; Oswald, Michaela

    2013-01-01

    In this contribution the synthesis and full structural and spectroscopic characterization of three asymmetrically substituted bis-1,2,4-triazoles, along with different energetic moieties like amino, nitro, nitrimino and azido moieties, is presented. Additionally, selected nitrogen-rich ionic derivatives have been prepared and characterized. This comparative study on the influence of these energetic moieties on structural and energetic properties constitutes a complete characterization includi...

  17. Novel Nanostructured Electrodes Obtained by Pyrolysis of Composite Polymeric Materials

    DEFF Research Database (Denmark)

    Amato, Letizia; Schulte, Lars; Heiskanen, Arto

    2015-01-01

    In this work, we compare pyrolyzed carbon derived from the photoresist SU‐8 alone or in combination with polystyrene and poly(styrene)‐block‐poly(dimethylsiloxane) copolymer (PS‐b‐PDMS), to be used as novel materials for micro‐ and nanoelectrodes. The pyrolyzed carbon films are evaluated with sca...

  18. Functional Scanning Probe Imaging of Nanostructured Solar Energy Materials.

    Science.gov (United States)

    Giridharagopal, Rajiv; Cox, Phillip A; Ginger, David S

    2016-09-20

    From hybrid perovskites to semiconducting polymer/fullerene blends for organic photovoltaics, many new materials being explored for energy harvesting and storage exhibit performance characteristics that depend sensitively on their nanoscale morphology. At the same time, rapid advances in the capability and accessibility of scanning probe microscopy methods over the past decade have made it possible to study processing/structure/function relationships ranging from photocurrent collection to photocarrier lifetimes with resolutions on the scale of tens of nanometers or better. Importantly, such scanning probe methods offer the potential to combine measurements of local structure with local function, and they can be implemented to study materials in situ or devices in operando to better understand how materials evolve in time in response to an external stimulus or environmental perturbation. This Account highlights recent advances in the development and application of scanning probe microscopy methods that can help address such questions while filling key gaps between the capabilities of conventional electron microscopy and newer super-resolution optical methods. Focusing on semiconductor materials for solar energy applications, we highlight a range of electrical and optoelectronic scanning probe microscopy methods that exploit the local dynamics of an atomic force microscope tip to probe key properties of the solar cell material or device structure. We discuss how it is possible to extract relevant device properties using noncontact scanning probe methods as well as how these properties guide materials development. Specifically, we discuss intensity-modulated scanning Kelvin probe microscopy (IM-SKPM), time-resolved electrostatic force microscopy (trEFM), frequency-modulated electrostatic force microscopy (FM-EFM), and cantilever ringdown imaging. We explain these developments in the context of classic atomic force microscopy (AFM) methods that exploit the physics of

  19. Elastomer-Carbon Nanostructure Composites as Prospective Materials for Flexible Robotic Tactile Sensors

    OpenAIRE

    Knite, M; Podiņš, G; Zīke, S; Zavickis, J

    2008-01-01

    Our recent achievements in the design, processing and studies of physical properties of elastomer – nano-structured carbon composites as prospective compressive strain sensor materials for robotic tactile elements are presented. Composites made of polyisoprene matrix and high-structured carbon black or multi-wall carbon nano-tube filler have been designed and manufactured to develop completely flexible conductive polymer nano-composites for tactile sensing elements. Electrical resistance of t...

  20. Facile one-pot synthesis of multi-yolk-shell Bi@C nanostructures by the nanoscale Kirkendall effect.

    Science.gov (United States)

    Cui, C M; Guo, X H; Geng, Y M; Dang, T T; Xie, G; Chen, S P; Zhao, F Q

    2015-06-01

    Multi-yolk-shell Bi@C nanostructures were prepared via a facile one-pot template-free hydrothermal approach. The prepared Bi@C nanostructures can act as a solid catalyst in the thermal decomposition of cyclotrimethylenetrinitramine (RDX) and display excellent catalytic activity, which highlights their application in the field of energetic materials.

  1. Synthesis of pentafluorosulfanylpyrazole and pentafluorosulfanyl-1,2,3-triazole and their derivatives as energetic materials by click chemistry.

    Science.gov (United States)

    Ye, Chengfeng; Gard, Gary L; Winter, Rolf W; Syvret, Robert G; Twamley, Brendan; Shreeve, Jean'ne M

    2007-09-13

    1-Pentafluorosulfanyl acetylene and its derivatives react with azide or diazomethane giving rise to an SF5-substituted 1,2,3-triazole or pyrazole. The SF5 group increases density remarkably and as a result enhances the detonation performance of the energetic materials relative to the CF3 group.

  2. SOME PROGRESS IN NANOSTRUCTURED LUMINESCENT MATERIALS%纳米发光材料研究的若干进展

    Institute of Scientific and Technical Information of China (English)

    周永慧; 林君; 张洪杰

    2001-01-01

    本文综述了纳米发光材料的研究进展情况,着重总结了(稀土)掺杂型纳米发光材料的制备方法和表征手段,同时介绍了这些纳米发光材料的性质和应用,并对其未来发展趋势进行了展望。%The progress in nanostructured luminescent materials has been reviewed in this paper.Emphases are laid on the synthesis and characterization methods of (rare earth) doped nanostructured luminescent materials.In the meanwhile,the properties and applications of the nanostructured luminescent materials are introduced,and the future development trends for the nanostructured luminescent materials are forecasted in brief.

  3. Nanostructured Composite Materials for High Temperature Thermoelectric Energy Conversion

    Science.gov (United States)

    2012-08-29

    Mechanical Testing Measurements were made of the Young’s modulus and toughness of half-Heusler bulk materials with compositions [Zro.5Hfo...will be optimized to meet the needs of engineered devices. A microhardness tester will be used to obtain hardness measurements and determine the...modulus of elasticity for thermoelectric samples. These tests will be used to assess homogeneity of mechanical properties as a function of processing

  4. Nanostructured materials for biological imaging and chemical sensing

    OpenAIRE

    Yıldırım, Adem

    2014-01-01

    Cataloged from PDF version of thesis. Includes bibliographical references (leaves 116-139). Thesis (Ph. D.): Bilkent University, Materials Science and Nanotechnology Program, İhsan Doğramacı Bilkent University, 2014. In the recent years, the design and synthesis of fluorescent nanoparticles for biological and chemical sensing applications have received considerable attention due to the excellent photostability and emission intensity of fluorescent nanoparticles and the intri...

  5. Structure-Interaction Effects In Novel Nanostructured Materials

    Science.gov (United States)

    Le, Nam B.

    Recent advances in experimental and computational methods have opened up new directions in graphene fundamental studies. In addition to understanding the basic properties of this material and its quasi-one dimensional structures, significant efforts are devoted to describing their long ranged dispersive interactions. Other two-dimensional materials, such as silicene, germanene, and transition metal dichalcogenides, are also being investigated aiming at finding complementary to graphene systems with other "wonder" properties. The focus of this work is to utilize first principles simulations methods to build our basic knowledge of structure-interaction relations in two-dimensional materials and design their properties. In particular, mechanical folding and extended defects in zigzag and armchair graphene nanoribbons can be used to modulate their electronic and spin polarization characteristics and achieve different stacking patterns. Our simulations concerning zigzag silicene nanoribbons show width-dependent antiferromagnetic-ferromagnetic transitions unlike the case of zigzag graphene nanoribbons, which are always antiferromagnetic. Heterostructures, build by stacking graphene, silicene, and MoS2, are also investigated. It is found that hybridization alters the electronic properties of the individual layers and new flexural and breathing phonon modes display unique behaviors in the heterostructure compositions. Anchored to SiC substrate graphene nanoribbons are also proposed as possible systems to be used in graphene electronics. Our findings are of importance not only for fundamental science, but they could also be used for future experimental developments.

  6. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    Science.gov (United States)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; Lowther, S. E.; Lillehei, P. T.; Bryant, R. G.

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  7. Hot spots in energetic materials generated by infrared and ultrasound, detected by thermal imaging microscopy.

    Science.gov (United States)

    Chen, Ming-Wei; You, Sizhu; Suslick, Kenneth S; Dlott, Dana D

    2014-02-01

    We have observed and characterized hot spot formation and hot-spot ignition of energetic materials (EM), where hot spots were created by ultrasonic or long-wavelength infrared (LWIR) exposure, and were detected by high-speed thermal microscopy. The microscope had 15-20 μm spatial resolution and 8.3 ms temporal resolution. LWIR was generated by a CO2 laser (tunable near 10.6 μm or 28.3 THz) and ultrasound by a 20 kHz acoustic horn. Both methods of energy input created spatially homogeneous energy fields, allowing hot spots to develop spontaneously due to the microstructure of the sample materials. We observed formation of hot spots which grew and caused the EM to ignite. The EM studied here consisted of composite solids with 1,3,5-trinitroperhydro-1,3,5-triazine crystals and polymer binders. EM simulants based on sucrose crystals in binders were also examined. The mechanisms of hot spot generation were different with LWIR and ultrasound. With LWIR, hot spots were most efficiently generated within the EM crystals at LWIR wavelengths having longer absorption depths of ∼25 μm, suggesting that hot spot generation mechanisms involved localized absorbing defects within the crystals, LWIR focusing in the crystals or LWIR interference in the crystals. With ultrasound, hot spots were primarily generated in regions of the polymer binder immediately adjacent to crystal surfaces, rather than inside the EM crystals.

  8. Ignition analysis of a porous energetic material. 2. Ignition at a closed heated end

    Energy Technology Data Exchange (ETDEWEB)

    Alexander M. Telegentor; Stephen B. Margolis; Forman A. Williams

    1998-11-01

    A continuation of an ignition analysis for porous energetic materials subjected to a constant energy flux is presented. In the first part, the analysis was developed for the case of an open-end, semi-infinite material such that gas flow, generated by thermal expansion, flowed out of the porous solid, thereby removing energy from the system. In the present study, the case of a closed end is considered, and thus the thermally-induced gas flow is now directed into the solid. In these studies, an asymptotic perturbation analysis, based on the smallness of the gas-to-solid density ratio and the largeness of the activation energy, is utilized to describe the inert and transition stages leading to thermal runaway. In both cases it is found that the effects of porosity provide a leading-order reduction in the time to ignition relative to that for the nonporous problem, arising from the reduced amount of solid material that must be heated and the difference in thermal conductivities of the solid and gaseous phases. A correction to the leading-order ignition-delay time, however, is provided by the convective flow of gas through the solid, and the sign of this correction is shown to depend on the direction of the gas flow. Thus, gas flowing out of an open-end solid was previously shown to give a positive correction to the leading-order time to ignition. Here, however, it is demonstrated that when the flow of gas is directed into the porous solid, the relative transport effects associated with the gas flow serve to preheat the material, resulting in a negative correction and hence a decrease in the ignition-delay time.

  9. Stability of quasi-steady deflagrations in confined porous energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Alexander M. Telengator; Stephen B. Margolis; Forman A. Williams

    2000-03-01

    Previous analyses have shown that unconfined deflagrations propagating through both porous and nonporous energetic materials can exhibit a thermal/diffusive instability that corresponds to the onset of various oscillatory modes of combustion. For porous materials, two-phase-flow effects, associated with the motion of the gas products relative to the condensed material, play a significant role that can shift stability boundaries with respect to those associated with the nonporous problem. In the present work, additional significant effects are shown to be associated with confinement, which produces an overpressure in the burned-gas region that leads to reversal of the gas flow and hence partial permeation of the hot gases into the unburned porous material. This results in a superadiabatic effect that increases the combustion temperature and, consequently, the burning rate. Under the assumption of gas-phase quasi-steadiness, an asymptotic model is presented that facilitates a perturbation analysis of both the basic solution, corresponding to a steadily propagating planar combustion wave, and its stability. The neutral stability boundaries collapse to the previous results in the absence of confinement, but different trends arising from the presence of the gas-permeation layer are predicted for the confined problem. Whereas two-phase-flow effects are generally destabilizing in the unconfined geometry, the effects of increasing overpressure and hence combustion temperature associated with confinement are shown to be generally stabilizing with respect to thermal/diffusive instability, analogous to the effects of decreasing heat losses on combustion temperature and stability in single-phase deflagrations.

  10. High resolution backscattering studies of nanostructured magnetic and semiconducting materials

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, A. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal)]. E-mail: afonseca@itn.pt; Franco, N. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal); Alves, E. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Barradas, N.P. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Leitao, J.P. [Departamento de Fisica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Sobolev, N.A. [Departamento de Fisica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Banhart, D.F. [Z. E. Elektronenmikroskopie, Universitaet Ulm, Albert-Einstein-Allee 11, D-89069 Ulm (Germany); Presting, H. [Daimler-Chrysler Forschungszentrum, 89081 Ulm (Germany); Ulyanov, V.V. [Institute of Semiconductor Physics, 630090 Novosibirsk (Russian Federation); Nikiforov, A.I. [Institute of Semiconductor Physics, 630090 Novosibirsk (Russian Federation)

    2005-12-15

    Low dimension structures raises inevitably new technological challenges in materials science. The new structures must fulfill stringent requirements in composition, crystalline quality and interface sharpness among others. We present and discuss the results of Si/Ge quantum structures and FePt/C multilayer structures deposited at different temperatures by ion beam sputtering. Evidence for the presence of FePt nanoparticles embedded in the C matrix and Ge islands in Ge/Si multilayers structures was found. Size and stoichiometry of the nanoparticles and the multilayer periodicity was obtained using Rutherford backscattering at grazing angles of incidence. The strain state of the single crystalline layers was determined by tilt axis channelling.

  11. Nano-structured carbon materials for improved biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Razumiene, J., E-mail: julija.razumiene@bchi.vu.lt [Institute of Biochemistry, Vilnius University, Mokslininku 12, Vilnius 08662 (Lithuania); Sakinyte, I. [Institute of Biochemistry, Vilnius University, Mokslininku 12, Vilnius 08662 (Lithuania); Barkauskas, J. [Faculty of Chemistry, Vilnius University, Naugarduko 24, Vilnius 03225 (Lithuania); Baronas, R. [Faculty of Mathematics and Informatics, Vilnius University, Naugarduko 24, Vilnius 03225 (Lithuania)

    2015-04-15

    Graphical abstract: - Highlights: • Novel protocols of graphite oxidation were used for successful synthesis of GOPs. • Newly synthesized GOPs were applicable for electrode design in reagentless bioelectrocatalytic systems operating on direct electron transfer. • We show that bioelectrocatalytic processes strongly depend on functionalities, morphology and structural features of GOPs. - Abstract: A set of oxidized graphite samples have been newly synthesized using different protocols. Atomic force microscopy, Raman spectroscopy, thermal gravimetric analysis and Brunauer–Emmett–Teller analysis revealed the changes in structure and functionalities of obtained graphite oxidation products (GOPs) compared to pristine graphite. The substances have been tested as electrode materials applicable for bioelectrocatalytic systems using pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH). The application of GOPs allowed achieving the direct electron transfer (DET) from active site of PQQ-GDH to the electrode surface. Needless of additional electron transfer (ET) mediating compounds highly improved features of the biosensors. The efficiency of the biosensors has been evaluated for all types of biosensors varied from 32 μA/cm{sup 2} to 64 μA/cm{sup 2} using as electrode materials GOP1 and thermally reduced graphite oxide (TRGO), respectively. TRGO containing function groups (according TGA, ∼6% of the weight loss) and smallest particles (average diameter was ∼11 nm and the average height was ∼0.5 nm) exhibited the higher efficiency for ET acceleration in the biosensor acting on principle of DET.

  12. Thermoelectric and thermospintronic transport in Dirac material-based nanostructures

    Science.gov (United States)

    Chang, Po-Hao

    The growing need for power due to the rapid developments of the technologies has urged both engineers and scientists to study more sustainable types of energy. On the other hand, the improvement of our abilities although enable us, for example, to double the number of transistors in a dense integrated circuit approximately every two years (Moore's law), comes with side effect due to overheating. Taking advantage of thermoelectric effect has thus become one of the obvious solutions for the problems. But due to the poor efficiency of electricity-heat conversion, there are still challenges to be overcome in order to fully utilize the idea. In the past few years, the realization of graphene along with the discoveries of topological insulators (TI) which are both considered as Dirac material (DM) have offer alternative routs for improving the energy conversion efficiency through different approaches as well as novel quantum effects of materials themselves for investigation. The aim of this thesis is to present contributions to improving the efficiency of thermoelectric conversion as well as analyzing spin transport phenomena that occur in nano-devices. This thesis spans the areas of thermoelectric (TE) effect, spin-Seebeck effect (SSE) and the spin transport on the 3D topological insulator (TI). The different methods have been applied ranging from tight-binding (TB) approximation to density function theory (DFT) combined with non-equilibrium function (NEGF) techniques.

  13. Scalability of Phase Change Materials in Nanostructure Template

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2015-01-01

    Full Text Available The scalability of In2Se3, one of the phase change materials, is investigated. By depositing the material onto a nanopatterned substrate, individual In2Se3 nanoclusters are confined in the nanosize pits with well-defined shape and dimension permitting the systematic study of the ultimate scaling limit of its use as a phase change memory element. In2Se3 of progressively smaller volume is heated inside a transmission electron microscope operating in diffraction mode. The volume at which the amorphous-crystalline transition can no longer be observed is taken as the ultimate scaling limit, which is approximately 5 nm3 for In2Se3. The physics for the existence of scaling limit is discussed. Using phase change memory elements in memory hierarchy is believed to reduce its energy consumption because they consume zero leakage power in memory cells. Therefore, the phase change memory applications are of great importance in terms of energy saving.

  14. Crystal engineering of energetic materials: co-crystals of Ethylenedinitramine (EDNA) with modified performance and improved chemical stability.

    Science.gov (United States)

    Aakeröy, Christer B; Wijethunga, Tharanga K; Desper, John

    2015-07-27

    In the area of energetic materials, co-crystallization is emerging as a new technology for modifying or enhancing the properties of existing energetic substances. Ethylenedinitramine (EDNA) is a known energetic material which requires attention partly due to its chemical instability originating with its two highly acidic protons. In order to stabilize EDNA, a co-crystallization approach targeting the acidic protons using a series of co-crystallizing agents with suitable hydrogen-bond acceptors was employed. Fifteen attempted co-crystallizations resulted in eight successful outcomes and six of these were crystallographically characterized and all showed evidence of hydrogen bonds to the intended protons. Calculated detonation properties and experimental thermal and impact data for the co-crystals were obtained and compared with those of pure EDNA. The co-crystal of EDNA and 1,2-bis(4-pyridyl)ethylene was recognized as a more thermally stable alternative to EDNA while the co-crystal of EDNA and pyrazine N,N'-dioxide showed comparable detonation strengths (and much improved chemical stability) compared with that of EDNA. The co-crystals EDNA:4,4'-bipyridine and EDNA:pyrazine N,N'-dioxide were found to be about 50 % less impact sensitive than EDNA, all of which illustrate how co-crystallizations can be utilized for successfully modifying specific aspects of energetic materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Excited Electronic and Vibrational State Decomposition of Energetic Materials and Model Systems on Both Nanosecond and Femtosecond Time Scales

    Science.gov (United States)

    2014-07-22

    behavior of these species is then compared with that of very similar model systems in order to enable the synthesis of new materials that will be...systems in order to enable the synthesis of new materials that will be energetic by design. This must be the first step in the determination of the unique...1,2,4- triazole -1,1’-diol, respectively), following electronic state excitation, is investigated both experimentally and theoretically. Different from

  16. Poly(3-hexylthiophene) nanostructured materials for organic electronics applications.

    Science.gov (United States)

    Bhatt, M P; Magurudeniya, H D; Rainbolt, E A; Huang, P; Dissanayake, D S; Biewer, M C; Stefan, M C

    2014-02-01

    Semiconducting polymers have been developed during the last few decades and are currently used in various organic electronics applications. Regioregular poly(3-hexylthiophene) (P3HT) is the most employed semiconducting polymer for organic electronics applications. The development of living Grignard metathesis polymerization (GRIM) allowed the synthesis of P3HT with well-defined molecular weights and functional end groups. A large number of block copolymers containing P3HT have been reported, and their opto-electronic properties have been investigated. The performance of P3HT homopolymer and block copolymers in field-effect transistors and bulk heterojunction solar cells are discussed in this review. The morphology of the P3HT materials is also discussed.

  17. Nanostructured material for advanced energy storage : magnesium battery cathode development.

    Energy Technology Data Exchange (ETDEWEB)

    Sigmund, Wolfgang M. (University of Florida, Gainesville, FL); Woan, Karran V. (University of Florida, Gainesville, FL); Bell, Nelson Simmons

    2010-11-01

    Magnesium batteries are alternatives to the use of lithium ion and nickel metal hydride secondary batteries due to magnesium's abundance, safety of operation, and lower toxicity of disposal. The divalency of the magnesium ion and its chemistry poses some difficulties for its general and industrial use. This work developed a continuous and fibrous nanoscale network of the cathode material through the use of electrospinning with the goal of enhancing performance and reactivity of the battery. The system was characterized and preliminary tests were performed on the constructed battery cells. We were successful in building and testing a series of electrochemical systems that demonstrated good cyclability maintaining 60-70% of discharge capacity after more than 50 charge-discharge cycles.

  18. Nanostructured carbon materials decorated with organophosphorus moieties: synthesis and application

    Science.gov (United States)

    Biagiotti, Giacomo; Langè, Vittoria; Ligi, Cristina; Caporali, Stefano; Muniz-Miranda, Maurizio; Flis, Anna; Pietrusiewicz, K Michał; Ghini, Giacomo; Brandi, Alberto

    2017-01-01

    A new synthetic approach for the production of carbon nanomaterials (CNM) decorated with organophosphorus moieties is presented. Three different triphenylphosphine oxide (TPPO) derivatives were used to decorate oxidized multiwalled carbon nanotubes (ox-MWCNTs) and graphene platelets (GPs). The TPPOs chosen bear functional groups able to react with the CNMs by Tour reaction (an amino group), nitrene cycloaddition (an azido group) or CuAAC reaction (one terminal C–C triple bond). All the adducts were characterized by FTIR, Raman spectroscopy, TEM, XPS, elemental analysis and ICP-AES. The cycloaddition of nitrene provided the higher loading on ox-MWCNTs and GPs as well, while the Tour approach gave best results with nanotubes (CNTs). Finally, we investigated the possibility to reduce the TPPO functionalized CNMs to the corresponding phosphine derivatives and applied one of the materials produced as heterogeneous organocatalyst in a Staudinger ligation reaction.

  19. Nanostructure multilayer dielectric materials for capacitors and insulators

    Science.gov (United States)

    Barbee, Jr., Troy W.; Johnson, Gary W.

    1998-04-21

    A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3) in alternating layers to form a nano-laminate.

  20. Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion.

    Science.gov (United States)

    Chen, Kan-Sheng; Xu, Rui; Luu, Norman S; Secor, Ethan B; Hamamoto, Koichi; Li, Qianqian; Kim, Soo; Sangwan, Vinod K; Balla, Itamar; Guiney, Linda M; Seo, Jung-Woo T; Yu, Xiankai; Liu, Weiwei; Wu, Jinsong; Wolverton, Chris; Dravid, Vinayak P; Barnett, Scott A; Lu, Jun; Amine, Khalil; Hersam, Mark C

    2017-04-12

    Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at -20 °C, this work advances lithium-ion battery technology into unprecedented regimes of operation.

  1. Hexagonal CeO2 nanostructures: an efficient electrode material for supercapacitors.

    Science.gov (United States)

    Maheswari, Nallappan; Muralidharan, Gopalan

    2016-09-28

    Cerium oxide (CeO2) has emerged as a new and promising pseudocapacitive material due to its prominent valance states and extensive applications in various fields. In the present study, hexagonal CeO2 nanostructures have been prepared via the hydrothermal method employing cationic surfactant cetyl trimethyl ammonium bromide (CTAB). CTAB ensures a slow rate of hydrolysis to form small sized CeO2 nanostructures. The role of calcination temperature on the morphological, structural, electrochemical properties and cyclic stability has been assessed for supercapacitor applications. The mesoscopic hexagonal architecture endows the CeO2 with not only a higher specific capacity, but also with an excellent rate capability and cyclability. When the charge/discharge current density is increased from 2 to 10 A g(-1) the reversible charge capacity decreased from 927 F g(-1) to 475 F g(-1) while 100% capacity retention at a high current density of 20 A g(-1) even after 1500 cycles could be achieved. Furthermore, the asymmetric supercapacitor based on CeO2 exhibited a significantly higher energy density of 45.6 W h kg(-1) at a power density of 187.5 W kg(-1) with good cyclic stability. The electrochemical richness of the CeO2 nanostructure makes it a suitable electrode material for supercapacitor applications.

  2. Energetics Conditioning Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Energetics Conditioning Facility is used for long term and short term aging studies of energetic materials. The facility has 10 conditioning chambers of which 2...

  3. Energetics Conditioning Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Energetics Conditioning Facility is used for long term and short term aging studies of energetic materials. The facility has 10 conditioning chambers of which 2...

  4. Physical Delivery of Macromolecules using High-Aspect Ratio Nanostructured Materials.

    Science.gov (United States)

    Lee, Kunwoo; Lingampalli, Nithya; Pisano, Albert P; Murthy, Niren; So, Hongyun

    2015-10-28

    There is great need for the development of an efficient delivery method of macromolecules, including nucleic acids, proteins, and peptides, to cell cytoplasm without eliciting toxicity or changing cell behavior. High-aspect ratio nanomaterials have addressed many challenges present in conventional methods, such as cell membrane passage and endosomal degradation, and have shown the feasibility of efficient high-throughput macromolecule delivery with minimal perturbation of cells. This review describes the recent advances of in vitro and in vivo physical macromolecule delivery with high-aspect ratio nanostructured materials and summarizes the synthesis methods, material properties, relevant applications, and various potential directions.

  5. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials

    OpenAIRE

    2015-01-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase....

  6. An investigation into carbon nanostructured materials as catalyst support in proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Veltzé, Sune

    black support materials for low platinum containing electrocatalyst. This is partly due to their high electronic conductivity. Partly due to their high surface area needed for the dispersion of nanoparticulate metal-clusters. In addition carbon nano-structures (CNF, SWCNT, MWCNT etc.) are more durable...... dispersion methods as the weak Van der Waals forces prevent the solvatisation and dispersion carbon nano structured materials. As the dispersion of SWCNT, MWCNT and CNF exhibit colloidal dispersion behaviour, the usual methods of consist solvatisation in organic solvents, mixture of water and an organic...

  7. Rare earth based nanostructured materials: synthesis, functionalization, properties and bioimaging and biosensing applications

    Science.gov (United States)

    Escudero, Alberto; Becerro, Ana I.; Carrillo-Carrión, Carolina; Núñez, Nuria O.; Zyuzin, Mikhail V.; Laguna, Mariano; González-Mancebo, Daniel; Ocaña, Manuel; Parak, Wolfgang J.

    2017-06-01

    Rare earth based nanostructures constitute a type of functional materials widely used and studied in the recent literature. The purpose of this review is to provide a general and comprehensive overview of the current state of the art, with special focus on the commonly employed synthesis methods and functionalization strategies of rare earth based nanoparticles and on their different bioimaging and biosensing applications. The luminescent (including downconversion, upconversion and permanent luminescence) and magnetic properties of rare earth based nanoparticles, as well as their ability to absorb X-rays, will also be explained and connected with their luminescent, magnetic resonance and X-ray computed tomography bioimaging applications, respectively. This review is not only restricted to nanoparticles, and recent advances reported for in other nanostructures containing rare earths, such as metal organic frameworks and lanthanide complexes conjugated with biological structures, will also be commented on.

  8. Nanostructured membrane material designed for carbon dioxide separation

    KAUST Repository

    Yave, Wilfredo

    2010-03-15

    In this work carbon dioxide selective membrane materials from a commercially available poly(amide-b-ethylene oxide) (Pebax (R), Arkema) blended with polyethylene glycol ethers are presented. The preferred PEG-ether was PEG-dimethylether (PEG-DME). PEG-DME is well known as a physical solvent for acid gas absorption. It is used under the trade name Genosorb (R) in the Selexol (R) process (UOP) for acid gas removal from natural gas and synthesis gas. The combination of the liquid absorbent with the multiblock copolymer resulted in mechanically stable films with superior CO(2) separation properties. The addition of 50 wt.% PEG-DME to the copolymer resulted in a 8-fold increase of the carbon dioxide permeability; the CO(2)/H(2)-selectivity increased simultaneously from 9.1 to 14.9. It is shown that diffusivity as well as solubility of carbon dioxide is strongly increased by the blending of the copolymer with PEG-ethers. (c) 2009 Elsevier B.V. All rights reserved.

  9. Anisotropic Thermal Properties of Nanostructured Magnetic, Carbon and Hybrid Magnetic - Carbon Materials

    Science.gov (United States)

    Ramirez, Sylvester

    In this dissertation research we investigated thermal properties of three groups of nanostructured materials: (i) magnetic; (ii) reduced graphene oxide films; and (iii) hybrid magnetic -- graphite -- graphene composites. The thermal measurements were conducted using the transient "hot disk" and "laser flash" techniques. The rare-earth free nanostructured SrFe12O19 permanent magnets were produced by the current activated pressure assisted densification technique. The thermal conductivity of the nanostructured bulk magnets was found to range from 3.8 to 5.6 W/mK for the in-plane and 2.36 W/mk to 2.65 W/mK for the cross-plane directions, respectively. The heat conduction was dominated by phonons near the room temperature. The anisotropy of heat conduction was explained by the brick-like alignment of crystalline grains with the longer grain size in-plane direction. The thermal conductivity scales up with the average grain size and mass density of the material revealing weak temperature dependence. Using the nanostructured ferromagnetic Fe3O4 composites as an example system, we incorporated graphene and graphite fillers into magnetic material without changing their morphology. It was demonstrated that addition of 5 wt. % of equal mixture of graphene and graphite flakes to the composite results in a factor of x2.6 enhancement of the thermal conductivity without significant degradation of the saturation magnetization. We investigated thermal conductivity of free-standing reduced graphene oxide films subjected to a high-temperature treatment of up to 1000°C. It was found that the high-temperature annealing dramatically increased the in-plane thermal conductivity, K, of the films from ˜3 W/mK to ˜61 W/mK at room temperature. The cross-plane thermal conductivity, K⊥, revealed an interesting opposite trend of decreasing to a very small value of ˜0.09 W/mK in the reduced graphene oxide films annealed at 1000°C. The obtained films demonstrated an exceptionally strong

  10. Self-Assembly of Crystalline Structures of Magnetic Core-Shell Nanoparticles for Fabrication of Nanostructured Materials.

    Science.gov (United States)

    Xue, Xiaozheng; Wang, Jianchao; Furlani, Edward P

    2015-10-14

    A theoretical study is presented of the template-assisted formation of crystalline superstructures of magnetic-dielectric core-shell particles. The templates produce highly localized gradient fields and a corresponding magnetic force that guides the assembly with nanoscale precision in particle placement. The process is studied using two distinct and complementary computational models that predict the dynamics and energy of the particles, respectively. Both mono- and polydisperse colloids are studied, and the analysis demonstrates for the first time that although the particles self-assemble into ordered crystalline superstructures, the particle formation is not unique. There is a Brownian motion-induced degeneracy in the process wherein various distinct, energetically comparable crystalline structures can form for a given template geometry. The models predict the formation of hexagonal close packed (HCP) and face centered cubic (FCC) structures as well as mixed phase structures due to in-plane stacking disorders, which is consistent with experimental observations. The polydisperse particle structures are less uniform than the monodisperse particle structures because of the irregular packing of different-sized particles. A comparison of self-assembly using soft- and hard-magnetic templates is also presented, the former being magnetized in a uniform field. This analysis shows that soft-magnetic templates enable an order-of-magnitude more rapid assembly and much higher spatial resolution in particle placement than their hard-magnetic counterparts. The self-assembly method discussed is versatile and broadly applies to arbitrary template geometries and multilayered and multifunctional mono- and polydisperse core-shell particles that have at least one magnetic component. As such, the method holds potential for the bottom-up fabrication of functional nanostructured materials for a broad range of applications. This work provides unprecedented insight into the assembly

  11. The potential, limitations, and challenges of divide and conquer quantum electronic structure calculations on energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Jon R.; Magyar, Rudolph J.

    2012-02-01

    High explosives are an important class of energetic materials used in many weapons applications. Even with modern computers, the simulation of the dynamic chemical reactions and energy release is exceedingly challenging. While the scale of the detonation process may be macroscopic, the dynamic bond breaking responsible for the explosive release of energy is fundamentally quantum mechanical. Thus, any method that does not adequately describe bonding is destined to lack predictive capability on some level. Performing quantum mechanics calculations on systems with more than dozens of atoms is a gargantuan task, and severe approximation schemes must be employed in practical calculations. We have developed and tested a divide and conquer (DnC) scheme to obtain total energies, forces, and harmonic frequencies within semi-empirical quantum mechanics. The method is intended as an approximate but faster solution to the full problem and is possible due to the sparsity of the density matrix in many applications. The resulting total energy calculation scales linearly as the number of subsystems, and the method provides a path-forward to quantum mechanical simulations of millions of atoms.

  12. Thermally stable 3,6-dinitropyrazolo[4,3-c]pyrazole-based energetic materials.

    Science.gov (United States)

    Zhang, Jiaheng; Parrish, Damon A; Shreeve, Jean'ne M

    2014-10-01

    3,6-Dinitropyrazolo[4,3-c]pyrazole was prepared using an efficient modified process. With selected cations, ten nitrogen-rich energetic salts and three metal salts were synthesized in high yield based on the 3,6-dinitropyrazolo[4,3-c]pyrazolate anion. These compounds were fully characterized by IR and multinuclear NMR spectroscopies, as well as elemental analyses. The structures of the neutral compounds 4 and its salt 16 were confirmed by single-crystal X-ray diffraction showing extensive hydrogen-bonding interactions. The neutral pyrazole precursor and its salts are remarkably thermally stable. Based on the calculated heats of formation and measured densities, detonation pressures (22.5-35.4 GPa) and velocities (7948-9005 m s(-1)) were determined, and they compare favorably with those of TNT and RDX. Their impact and friction sensitivities range from 12 to >40 J and 80 to 360 N, respectively. These properties make them competitive as insensitive and thermally stable high-energy density materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Energetic materials identification by laser-induced breakdown spectroscopy combined with artificial neural network.

    Science.gov (United States)

    Farhadian, Amir Hossein; Tehrani, Masoud Kavosh; Keshavarz, Mohammad Hossein; Darbani, Seyyed Mohammad Reza

    2017-04-20

    In this study, for the first time to the best of our knowledge, a combination of the laser-induced breakdown spectroscopy (LIBS) technique and artificial neural network (ANN) analysis has been implemented for the identification of energetic materials, including TNT, RDX, black powder, and propellant. Also, aluminum, copper, inconel, and graphite have been used for more accurate investigation and comparison. After the LIBS test and spectrum acquisition on all samples in both air and argon ambient, optimized neural networks were designed by LIBS data. Based on input data, three ANN algorithms are proposed: the first is fed with the whole LIBS spectra in air (ANN1) and the second with the principle component analysis (PCA) scores of each spectrum in air (ANN2) and the other with the PCA scores of the spectrum in Ar (ANN3). According to the results, error of the network is very low in ANN2 and 3 and the best identification and discrimination was obtained by ANN3. After these, in order to validate and for more investigation of this combined method, we also used Al/RDX standard samples for analysis.

  14. Detection of highly energetic materials on non-reflective substrates using quantum cascade laser spectroscopy.

    Science.gov (United States)

    Castro-Suarez, John R; Hidalgo-Santiago, Migdalia; Hernández-Rivera, Samuel P

    2015-09-01

    A quantum cascade laser spectrometer was used to obtain the reflection spectra of highly energetic materials (HEMs) deposited on nonideal, low-reflectivity substrates, such as travel-bag fabric (polyester), cardboard, and wood. Various deposition methods were used to prepare the standards and samples in the study. The HEMs used were the nitroaromatic explosive 2,4,6-trinitrotoluene (TNT), the aliphatic nitrate ester pentaerythritol tetranitrate (PETN), and the aliphatic nitramine 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). Chemometrics algorithms were applied to analyze the recorded spectra. Partial least squares (PLS) regression analysis was used to find the best correlation between the infrared signals and the surface concentrations of the samples, and PLS combined with discriminant analysis (PLS-DA) was used to discriminate, classify, and identity similarities in the spectral datasets. Several preprocessing steps were applied to prepare the mid-infrared spectra of HEMs deposited on the target substrates. The results demonstrate that the infrared vibrational method described in this study is well suited for the rapid screening analysis of HEMs on low-reflectivity substrates when a supervised model has been previously constructed or when a reference spectrum of the clean substrate can be acquired to be subtracted from the HEM-substrate spectrum.

  15. Analysis of selected specimens from the STS-46 Energetic Oxygen Interaction with Materials-3 experiment

    Science.gov (United States)

    Golden, Johnny L.; Bourassa, Roger J.; Dursch, Harry W.; Pippin, H. Gary

    1995-01-01

    The Energetic Oxygen Interaction with Materials 3 (EOIM-3) experiment was flown on the STS-46 mission, which was launched on 31 Jul. 1992 and returned 8 Aug. 1992. Boeing specimens were located on both the NASA Marshall Space Flight Center (MSFC) tray and the Ballistic Missile Defense Organization (BMDO) tray integrated by the Jet Propulsion Laboratory (JPL). The EOIM-3 pallet was mounted in the Space Shuttle payload bay near the aft bulkhead. During the mission, the atomic oxygen (AO) exposure levels of specimens in these passive sample trays was about 2.3 x 10(exp 20) atoms/sq cm. The specimens also received an estimated 22 equivalent sun hours of solar exposure. In addition, it appears that the EOIM-3 pallet was exposed to a silicone contamination source and many specimens had a thin layer of silicon based deposit on their surfaces after the flight. The specimens on the MSFC tray included seven solid film lubricants, a selection of butyl rubber (B612) and silicone (S383) o-rings, three indirect scatter surfaces, and Silver/Fluorinated Ethylene Propylene (Ag/FEP) and Chemglaze A276 specimens which had previously flown on trailing edge locations of the Long Duration Exposure Facility (LDEF). The specimens on the JPL tray included composites previously flown on LDEF and two indirect scattering surfaces.

  16. Effects of bimetallic catalysts on synthesis of nitrogen-doped carbon nanotubes as nanoscale energetic materials

    Institute of Scientific and Technical Information of China (English)

    Hao Liu; Yong Zhang; Ruying Li; Xueliang Sun; Hakima Abou-Rachid

    2011-01-01

    Well aligned nitrogen-doped carbon nanotubes (CNx-NTs),as energetic materials,are synthesized on a silicon substrate by aerosol-assisted chemical vapor deposition.Tungsten (W) and molybdenum (Mo) metals are respectively introduced to combine with iron (Fe) to act as a bimetallic co-catalyst layer.Correlations between the composition and shape of the co-catalyst and morphology,size,growth rate and nitrogen doping amount of the synthesized CNx-NTs are investigated by secondary and backscattered electron imaging in a field emission scanning electron microscope (FESEM) and X-ray photoelectron spectrometer (XPS).Compared to pure iron catalyst.W-Fe co-catalyst can result in lower growth rate,larger diameter and wider size distribution of the CNx-NTs; while incorporation of molybdenum into the iron catalyst layer can reduce the diameter and size distribution of the nanotubes.Compared to the sole iron catalyst,Fe-W catalyst impedes nitrogen doping while Fe-Mo catalyst promotes the incorporation of nitrogen into the nanotubes.The present work indicates that CNx-NTs with modulated size,growth rate and nitrogen doping concentration are expected to be synthesized by tuning the size and composition of co-catalysts,which may find great potential in producing CNx-NTs with controlled structure and properties.

  17. Explosive Compations of Intermetallic-Forming Powder Mixtures for Fabricating Structural Energetic Materials

    Science.gov (United States)

    Du, S. W.; Aydelotte, B.; Fondse, D.; Wei, C.-T.; Jiang, F.; Herbold, E.; Vecchio, K.; Meyers, M. A.; Thadhani, N. N.

    2009-12-01

    A double-tube implosion geometry is used to explosively shock consolidate intermetallic-forming Ni-Al, Ta-Al, Nb-Al, Mo-Al and W-Al powder mixtures for fabricating bulk structural energetic materials, with mechanical strength and ability to undergo impact-initiated exothermic reactions. The compacts are characterized based on uniformity of micro structure and degree of densification. Mechanical properties of the compacts are characterized over the strain-rate range of 10-3 to 104 s-1. The impact reactivity is determined using rod-on-anvil experiments, in which disk-shaped compacts mounted on a copper projectile, are impacted against a steel anvil in using a 7.62 mm gas gun. The impact reactivity of the various explosively-consolidated reactive powder mixture compacts is correlated with overall kinetic energy and impact stress to determine their influence on threshold for reaction initiation. The characteristics of the various compacts, their mechanical properties and impact-initiated chemical reactivity will be described in this paper.

  18. Molecular Theory of Detonation Initiation: Insight from First Principles Modeling of the Decomposition Mechanisms of Organic Nitro Energetic Materials.

    Science.gov (United States)

    Tsyshevsky, Roman V; Sharia, Onise; Kuklja, Maija M

    2016-02-19

    This review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation initiation theory in a widely agreed upon form. However, recent advances in experimental and theoretical methods allow for a constructive and rigorous approach to design and test the theory or at least some of its fundamental building blocks. In this review, we analyzed a set of select experimental and theoretical articles, which were augmented by our own first principles modeling and simulations, to reveal new trends in energetic materials and to refine known existing correlations between their structures, properties, and functions. Our consideration is intentionally limited to the processes of thermally stimulated chemical reactions at the earliest stage of decomposition of molecules and materials containing defects.

  19. Molecular Theory of Detonation Initiation: Insight from First Principles Modeling of the Decomposition Mechanisms of Organic Nitro Energetic Materials

    Directory of Open Access Journals (Sweden)

    Roman V. Tsyshevsky

    2016-02-01

    Full Text Available This review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation initiation theory in a widely agreed upon form. However, recent advances in experimental and theoretical methods allow for a constructive and rigorous approach to design and test the theory or at least some of its fundamental building blocks. In this review, we analyzed a set of select experimental and theoretical articles, which were augmented by our own first principles modeling and simulations, to reveal new trends in energetic materials and to refine known existing correlations between their structures, properties, and functions. Our consideration is intentionally limited to the processes of thermally stimulated chemical reactions at the earliest stage of decomposition of molecules and materials containing defects.

  20. Disposal of energetic materials by alkaline pressure hydrolysis and combined techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bunte, G.; Krause, H.H.; Hirth, T. [Fraunhofer-Institut fuer Chemische Technologie (ICT), Pfinztal-Berghausen (Germany)

    1997-07-01

    Due to the reduction of armament and especially due to the German reunification we are met by objective of the diposal of energetic materials. Environmentally friendly disposal methods available for the different propellants, explosives and pyrotechnics are urgently needed. The main component of gun and rocket propellants is the energetic polymer nitrocellulose. One method to dispose nitrocellulose containing propellants is the combination of rapid chemical destruction by pressure hydrolysis and the biological degradation of the reaction mixture. The study describes the results of pressure hydrolysis of different gun and rocket propellants. Under alkaline conditions (propellant to NaOH ratio 2.3:1; reaction temperature 150 C; pressure below 30 bar) biological degradable reaction products were formed. The main products in the liquid phase were simple mono- and dicarboxylic acids. Dependent on the reaction conditions 30-50% of the nitrogen content of the propellants was transformed to nitrite and nitrate. The gaseous nitrogen containing products were N{sub 2} (16-46%), N{sub 2}O (2-23%), NO{sub x} (0-5%). Overall 40%-60% of the propellant nitrogen was transformed to gaseous products. In the solid residues a nitrogen content between 2% and 9% was found. The residues were mostly due to additives used in propellant manufacturing. In the case of nitrocellulose pressure hydrolysis below 30 bar and reaction temperature about 150 C are sufficient. (orig.) [Deutsch] Nicht zuletzt aufgrund der in den letzten Jahren erfolgten Abruestungsmassnahmen sowie auch der Wiedervereinigung beider deutscher Staaten ergab sich die Problematik der Entsorgung von energetischen Materialien. Alternativ zur Verbrennung besteht Bedarf an der Entwicklung von Entsorgungsverfahren, die eine umweltfreundliche Entsorgung von Treibladungspulvern, Raketenfesttreibstoffen oder pyrotechnischen Komponenten ermoeglichen. Eine interessante Methode zur Beseitigung von auf Nitrocellulose basierenden

  1. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials.

    Science.gov (United States)

    Kamarulzaman, Norlida; Kasim, Muhd Firdaus; Rusdi, Roshidah

    2015-12-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase. UV-visible spectroscopy showed that materials in the nanostructured state exhibit band gap widening with respect to their micron state while for the doped compounds exhibited band gap narrowing both in the nano and micron states with respect to the pure ZnO materials. The degree of band gap change was dependent on the doped elements and crystallite size. X-ray photoelectron spectroscopy (XPS) revealed that there were shifts in the valence bands. From both UV-visible and XPS spectroscopy, it was found that the mechanism for band gap narrowing was due to the shifting of the valance band maximum and conduction band minimum of the materials. The mechanisms were different for different samples depending on the type of dopant and dimensional length scales of the crystallites.

  2. Nanostructure-based plasmon-enhanced Raman spectroscopy for surface analysis of materials

    Science.gov (United States)

    Ding, Song-Yuan; Yi, Jun; Li, Jian-Feng; Ren, Bin; Wu, De-Yin; Panneerselvam, Rajapandiyan; Tian, Zhong-Qun

    2016-06-01

    Since 2000, there has been an explosion of activity in the field of plasmon-enhanced Raman spectroscopy (PERS), including surface-enhanced Raman spectroscopy (SERS), tip-enhanced Raman spectroscopy (TERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). In this Review, we explore the mechanism of PERS and discuss PERS hotspots — nanoscale regions with a strongly enhanced local electromagnetic field — that allow trace-molecule detection, biomolecule analysis and surface characterization of various materials. In particular, we discuss a new generation of hotspots that are generated from hybrid structures combining PERS-active nanostructures and probe materials, which feature a strong local electromagnetic field on the surface of the probe material. Enhancement of surface Raman signals up to five orders of magnitude can be obtained from materials that are weakly SERS active or SERS inactive. We provide a detailed overview of future research directions in the field of PERS, focusing on new PERS-active nanomaterials and nanostructures and the broad application prospect for materials science and technology.

  3. Synthesis of nanostructured manganese oxides based materials and application for supercapacitor

    Science.gov (United States)

    Dung Dang, Trung; Le, Thi Thu Hang; Bich Thuy Hoang, Thi; Mai, Thanh Tung

    2015-01-01

    Manganese oxides are important materials with a variety of applications in different fields such as chemical sensing devices, magnetic devices, field-emission devices, catalysis, ion-sieves, rechargeable batteries, hydrogen storage media and microelectronics. To open up new applications of manganese oxides, novel morphologies or nanostructures are required to be developed. Via sol—gel and anodic electrodeposition methods, M (Co, Fe) doped manganese oxides were prepared. On the other hand, nanostructured (nanoparticles, nanorods and hollow nanotubes) manganese oxides were synthesized via a process including a chemical reaction with carbon nanotubes (CNTs) templates followed by heat treatment. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV) and impedance spectroscopy (EIS) were used for characterization of the prepared materials. The influence of chemical reaction conditions, heat treatment and template present on the morphology, structure, chemical and electrochemical properties of the prepared materials were investigated. Chronopotentiometry (CP) and CV results show high specific capacitance of 186.2 to 298.4 F g-1 and the charge/discharge stability of the prepared materials and the ideal pseudocapacitive behaviors were observed. These results give an opening and promising application of these materials in advanced energy storage applications.

  4. Nitramines with varying sensitivities: functionalized dipyrazolyl-N-nitromethanamines as energetic materials.

    Science.gov (United States)

    Zhang, Jiaheng; He, Chunlin; Parrish, Damon A; Shreeve, Jean'ne M

    2013-07-01

    1,3-Dichloro-2-nitro-2-azapropane is an excellent precursor to dense energetic functionalized dipyrazolyl-N-nitromethanamines. This new family of energetic compounds was fully characterized by using (1)H, (13)C, and (15)N NMR and IR spectroscopy, differential scanning calorimetry, elemental analysis, and impact sensitivity tests. Additionally, single-crystal X-ray structuring was done for 3 and 5·CH3CN, which gave insight into structural characteristics. The experimentally determined densities of 2-9 fall between 1.69 and 1.90 g cm(-3). Heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 programs, respectively. The influence of different energetic moieties on the structural and energetic properties was established theoretically. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Properties of heterogeneous energetic materials under high strain, high strain rate deformation

    Science.gov (United States)

    Cai, Jing

    Heterogeneous energetic materials have many applications. Their dynamic behavior and microstructural evolution upon plastic deformation have remained not fully understood. The following heterogeneous materials were investigated in the this study: the pure PTFE (usually a mixture of crystalline and amorphous phases), PTFE-Sn, PTFE-Al, PTFE-Al-W, and carbon fibers filled Al alloy. Sample manufacturing processes involving ball milling and Cold Isostatic Pressing were employed. Quasi-static and Hopkinson bar tests were carried out to obtain the compressive strengths of composites. The Conventional Thick-walled Cylinder (TWC) method and newly developed small-scale Hopkinson bar based TWC experiments were conducted to investigate single shear bands and their assembly. Conventional and "soft" drop-weight tests were performed to examine the mechanical properties and the initiation of chemical reactions. Scanning Electron Microscopy was used to detect the details of the microstructures and failure mechanisms of heterogeneous materials. New features in the dynamic behavior of heterogeneous materials were observed. They include the following: (1) Strain softening, instead of thermal softening, is the main mechanism in the initiation of shear bands in explosively driven TWC tests of solid PTFE. (2) Cold isostatically pressed PTFE-Sn samples were more stable with respect to shear localization than solid PTFE. (3) The dynamic collapse of solid PTFE-Al samples with different particle sizes was accomplished with the shear localization bands and cracks. (4) Force chains in the fine W and Al particles were attributed to the high strength of the porous PTFE-Al-W composite containing fine W particles in comparison with composites with coarse W particles. (5) Debonding of metal particles from the PTFE matrix and the fracture of the matrix were identified to be two major mechanisms for the failure of the PTFE-Al-W composites. (6) The formation of PTFE nano-fibers during high strain flow

  6. Thermoelectric properties of LaFe3CoSb12 skutterudite materials with different nanostructures

    Institute of Scientific and Technical Information of China (English)

    LU Pengxian; WANG Chunhua; YAN Guojin; ZOU Wenjun; HU Xing

    2011-01-01

    Nanostructures with different morphologies could profoundly influence the electron and phonon transport in thermoelectric materials and thus their properties could be improved by tuning the nanostructures.The LaFe3CoSb12 skutterudite nano powders with different morphologies were fabricated via a hydro/solvo thermal route.The microstructures of the hot-pressed LaFe3CoSb12 bulks were characterized through X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the effects of the nanostructures on the thermoelectric properties were investigated by measuring the electrical conductivity,the Seebeck coefficient and the thermal conductivity.The results suggested that the mixed morphology of nanorods and nanospheres could enhance the electrical conductivity largely although the Seebeck coefficient was decreased and the themal conductivity was increased slightly.Differently,a higher Seebeck coefficient,a lower thermal conductivity and a lower electrical conductivity could be obtained for the LaFe3CoSb12 bulk with a single morphology of nanospheres.Consequently,the figure of merit of LaFe3CoSb12 bulk with a mixed morphology of nanorods and nanospheres could be increased by about 59% as compared to that with a single morphology of nanospheres.

  7. Complex Nanostructures from Materials based on Metal-Organic Frameworks for Electrochemical Energy Storage and Conversion.

    Science.gov (United States)

    Guan, Bu Yuan; Yu, Xin Yao; Wu, Hao Bin; Lou, Xiong Wen David

    2017-09-27

    Metal-organic frameworks (MOFs) have drawn tremendous attention because of their abundant diversity in structure and composition. Recently, there has been growing research interest in deriving advanced nanomaterials with complex architectures and tailored chemical compositions from MOF-based precursors for electrochemical energy storage and conversion. Here, a comprehensive overview of the synthesis and energy-related applications of complex nanostructures derived from MOF-based precursors is provided. After a brief summary of synthetic methods of MOF-based templates and their conversion to desirable nanostructures, delicate designs and preparation of complex architectures from MOFs or their composites are described in detail, including porous structures, single-shelled hollow structures, and multishelled hollow structures, as well as other unusual complex structures. Afterward, their applications are discussed as electrode materials or catalysts for lithium-ion batteries, hybrid supercapacitors, water-splitting devices, and fuel cells. Lastly, the research challenges and possible development directions of complex nanostructures derived from MOF-based-templates for electrochemical energy storage and conversion applications are outlined. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Nanostructured Carbon Materials as Supports in the Preparation of Direct Methanol Fuel Cell Electrocatalysts

    Directory of Open Access Journals (Sweden)

    María Jesús Lázaro

    2013-08-01

    Full Text Available Different advanced nanostructured carbon materials, such as carbon nanocoils, carbon nanofibers, graphitized ordered mesoporous carbons and carbon xerogels, presenting interesting features such as high electrical conductivity and extensively developed porous structure were synthesized and used as supports in the preparation of electrocatalysts for direct methanol fuel cells (DMFCs. The main advantage of these supports is that their physical properties and surface chemistry can be tailored to adapt the carbonaceous material to the catalytic requirements. Moreover, all of them present a highly mesoporous structure, diminishing diffusion problems, and both graphitic character and surface area can be conveniently modified. In the present work, the influence of the particular features of each material on the catalytic activity and stability was analyzed. Results have been compared with those obtained for commercial catalysts supported on Vulcan XC-72R, Pt/C and PtRu/C (ETEK. Both a highly ordered graphitic and mesopore-enriched structure of these advanced nanostructured materials resulted in an improved electrochemical performance in comparison to the commercial catalysts assayed, both towards CO and alcohol oxidation.

  9. Development of sensors based on advanced micro- and nanostructured carbon materials

    Science.gov (United States)

    Mendoza Centeno, Frank Willi

    The thesis is focused on the development of sensors based on advanced micro- and nano-structured carbon materials. In particular, we developed prototype diamond-based ultraviolet photodetectors and carbon nanotubes-based gas sensors. We describe the method of preparation and characterization of the active carbon-based materials and their structural and compositional characterizations. This is followed by the corresponding device fabrication and testing. The thesis briefly gives an introduction to our current understanding about carbon materials, with emphasis on synthetic diamond and bamboo-like carbon nanotubes, and to the materials' properties that are useful for ultraviolet photodetectors and gas sensor applications. The thesis also give an overview of the experience gained through this research, and some suggestions for those who would like follow the research methods employ here. It provides experimental information learned through experience that may be helpful and avoid delays to the newer experimentalists.

  10. Nanostructured composites based on carbon nanotubes and epoxy resin for use as radar absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Valdirene Aparecida [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil); Folgueras, Luiza de Castro; Candido, Geraldo Mauricio; Paula, Adriano Luiz de; Rezende, Mirabel Cerqueira, E-mail: mirabelmcr@iae.cta.br [Instituto de Aeronautica e Espaco (IAE), Sao Jose dos Campos, SP (Brazil). Div. de Materiais; Costa, Michelle Leali [Universidade Estadual Paulista Julio de Mesquita Filho (DMT/UNESP), Guaratingueta, SP (Brazil). Dept. de Materiais e Tecnologia

    2013-07-01

    Nanostructured polymer composites have opened up new perspectives for multifunctional materials. In particular, carbon nanotubes (CNTs) present potential applications in order to improve mechanical and electrical performance in composites with aerospace application. The combination of epoxy resin with multi walled carbon nanotubes results in a new functional material with enhanced electromagnetic properties. The objective of this work was the processing of radar absorbing materials based on formulations containing different quantities of carbon nanotubes in an epoxy resin matrix. To reach this objective the adequate concentration of CNTs in the resin matrix was determined. The processed structures were characterized by scanning electron microscopy, rheology, thermal and reflectivity in the frequency range of 8.2 to 12.4 GHz analyses. The microwave attenuation was up to 99.7%, using only 0.5% (w/w) of CNT, showing that these materials present advantages in performance associated with low additive concentrations (author)

  11. Synthesis of one-molecule-thick single-crystalline nanosheets of energetic material for high-sensitive force sensor.

    Science.gov (United States)

    Yang, Guangcheng; Hu, Hailong; Zhou, Yong; Hu, Yingjie; Huang, Hui; Nie, Fude; Shi, Weimei

    2012-01-01

    Energetic material is a reactive substance that contains a great amount of potential energy, which is extremely sensitive to external stimuli like force. In this work, one-molecule-thick single-crystalline nanosheets of energetic material were synthesized. Very small force applied on the nanosheet proves to lead to the rotation of the tilted nitro groups, and subsequently change of current of the nanosheet. We apply this principle to design high-sensitive force sensor. A theoretical model of force-current dependence was established based on the nanosheets' molecular packing structure model that was well supported with the high resolution XPS, AFM analysis results. An ultra-low-force with range of several picoNewton to several nanoNewton can be measured by determination of corresponding current value.

  12. Collapse of elongated voids in porous energetic materials: Effects of void orientation and aspect ratio on initiation

    Science.gov (United States)

    Rai, Nirmal Kumar; Schmidt, Martin J.; Udaykumar, H. S.

    2017-04-01

    The sensitivity of porous energetic materials depends on mesostructural heterogeneities such as voids, defects, cracks, and grain boundaries. The mesostructure of pressed explosives contains voids of arbitrary shapes including elongated voids of various orientations and aspect ratios. Mesoscale simulations to date have analyzed the effect of void morphology on the sensitivity of energetic materials for idealized shapes such as cylindrical, conical, and elliptical. This work analyzes the sensitivity behavior of elongated voids in an HMX matrix subject to shock loading. Simulations show that sensitivity of elongated voids depends strongly on orientation as well as aspect ratio. Ranges of orientations and aspects ratios are identified that enhance or inhibit initiation. Insights obtained from single elongated void analyses are used to identify sensitive locations in an imaged mesostructure of a pressed explosive sample.

  13. Theoretical Study of the N-NO2 Bond Dissociation Energies for Energetic Materials with Density Functional Theory

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Hong; TANG Zheng-Xin; Abraham F.Jalbout; ZHANG Xian-Zhou; CHENG Xin-Lu

    2008-01-01

    The N-NO2 bond dissociation energies (BDEs) for 7 energetic materials were computed by means of accurate density functional theory (B3LYP, B3PW91 and B3P86) with 6-31G** and 6-311G** basis sets. By comparing the computed energies and experimental results, we find that the B3P86/6-311G** method can give good results of BDE, which has the mean absolute deviation of 1.30 kcal/mol. In addition, substituent effects were also taken into account. It is noted that the Hammett constants of substituent groups are related to the BDEs of the N-NO2 bond and the bond dissociation energies of the energetic materials studied decrease when increasing the number of NO2 group.

  14. Shock response of single crystal and nanocrystalline pentaerythritol tetranitrate: Implications to hotspot formation in energetic materials.

    Science.gov (United States)

    Cai, Y; Zhao, F P; An, Q; Wu, H A; Goddard, W A; Luo, S N

    2013-10-28

    hotspot formation related to initiation in energetic materials, in the absence of other, likely more effective, means for hotspot formation such as void collapse.

  15. Determination of nitroaromatic and nitramine type energetic materials in synthetic and real mixtures by cyclic voltammetry.

    Science.gov (United States)

    Üzer, Ayşem; Sağlam, Sener; Tekdemir, Yasemin; Ustamehmetoğlu, Belkıs; Sezer, Esma; Erçağ, Erol; Apak, Reşat

    2013-10-15

    Nitro-explosives contain reducible aromatic -NO2 groups or cyclic >N-NO2 bonds that may undergo reductive cleavage. This work reports the development of a cyclic voltammetric (CV) assay for nitro-aromatics (trinitrotoluene (TNT), dinitrotoluene (DNT)) and nitramines (1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)) using a glassy carbon electrode. This determination was first used for these energetic materials by resolving current responses of reduction potentials primarily due to one constituent but partly contributed by other constituents. Calibration curves of current intensity versus concentration were linear in the range of 30-120 mg L(-1) for RDX with a limit of detection (LOD) of 10.2 mg L(-1), 40-120 mg L(-1) for HMX (LOD=11.7 mg L(-1)), 40-120 mg L(-1) for TNT (LOD=11.2 mg L(-1)), and 40-140 mg L(-1) for DNT (LOD=10.8 mg L(-1)). Results showed that the CV method could provide a sensitive approach for the simultaneous determination of RDX and TNT in synthetic and real mixtures. Deconvolution of current contributions of mixtures at peak potentials of constituents was performed by multiple linear regression. The proposed method was successfully applied to the analysis of military explosives comp A5 and octol, and method validation was performed both against HPLC on a comp B (TNT+RDX) sample and against GC-MS on real post-blast residual samples containing both explosives.

  16. Inhibition of soil microbial activity by nitrogen-based energetic materials.

    Science.gov (United States)

    Kuperman, Roman G; Minyard, Morgan L; Checkai, Ronald T; Sunahara, Geoffrey I; Rocheleau, Sylvie; Dodard, Sabine G; Paquet, Louise; Hawari, Jalal

    2017-05-18

    We investigated individual toxicities of the nitrogen-based energetic materials (EMs) 2,4-dinitrotoluene (2,4-DNT); 2-amino-4,6-dinitrotoluene (2-ADNT); 4-amino-2,6-dinitrotoluene (4-ADNT); and nitroglycerin (NG) on microbial activity in Sassafras sandy loam (SSL) soil, which has physicochemical characteristics that support very high qualitative relative bioavailability for organic chemicals. Batches of SSL soil for basal respiration (BR) and substrate-induced respiration (SIR) assays were separately amended with individual EMs or acetone carrier control. Total microbial biomass carbon (biomass C) was determined from CO2 production increases after addition of 2500 mg/kg of glucose-water slurry to the soil. Exposure concentrations of each EM in soil were determined using US Environmental Protection Agency method 8330A. Basal respiration was the most sensitive endpoint for assessing the effects of nitroaromatic EMs on microbial activity in SSL, whereas SIR and biomass C were more sensitive endpoints for assessing the effects of NG in soil. The orders of toxicity (from greatest to least) were 4-ADNT > 2,4-DNT = 2-ADNT > NG for BR; but for SIR and biomass C, the order of toxicity was NG > 2,4-DNT > 2-ADNT = 4-ADNT. No inhibition of SIR was found up to and including the greatest concentration of each ADNT tested in SSL. These ecotoxicological data will be helpful in identifying concentrations of contaminant EMs in soil that present acceptable ecological risks for biologically mediated processes in soil. Environ Toxicol Chem 2017;9999:1-10. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2017 Wiley Periodicals Inc., on behalf of SETAC.

  17. Electric Spark Sensitivity of Polynitro Compounds. Part V. A Relationship between Electric Spark and Impact Sensitivities of Energetic Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The spark energy, EES, required for 50 percent initiation probability of 41 polynitro compounds was determined. The relationships between the EES values and impact sensitivity, expressed as drop energies Ed of the "first reaction", were established and discussed. The conclusion is made that depending on intermolecular interaction factors in crystals of energetic materials, the mechanism of impact energy transition to the reaction centre of their molecule can be differ from that of transition of energy of electric spark.

  18. Toxicity of Nitro-Heterocyclic and Nitroaromatic Energetic Materials to Folsomia candida in a Natural Sandy Loam Soil

    Science.gov (United States)

    2015-04-01

    FOLSOMIA CANDIDA IN A NATURAL SANDY LOAM SOIL ECBC-TR-1272 Carlton T. Phillips Ronald T. Checkai Roman G. Kuperman Michael Simini Jan E...SUBTITLE Toxicity of Nitro-Heterocyclic and Nitroaromatic Energetic Materials to Folsomia candida in a Natural Sandy Loam Soil 5a. CONTRACT NUMBER 5b...2,4-dinitrotoluene (2,4-DNT) Folsomia candida octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) 2,6-dinitrotoluene

  19. Permittivity of dielectric composite materials comprising graphene nanoribbons. The effect of nanostructure.

    Science.gov (United States)

    Dimiev, Ayrat; Zakhidov, Dante; Genorio, Bostjan; Oladimeji, Korede; Crowgey, Benjamin; Kempel, Leo; Rothwell, Edward J; Tour, James M

    2013-08-14

    New lightweight, flexible dielectric composite materials were fabricated by the incorporation of several new carbon nanostructures into a dielectric host matrix. Both the permittivity and loss tangent values of the resulting composites were widely altered by varying the type and content of the conductive filler. The dielectric constant was tuned from moderate to very high values, while the corresponding loss tangent changed from ultralow to extremely high. The data exemplify that nanoscale changes in the structure of the conductive filler result in dramatic changes in the dielectric properties of composites. A microcapacitor model most explains the behavior of the dielectric composites.

  20. Compressibility of nanostructured Fe-Cu materials prepared by mechanical milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Olsen, J.S.; Gerward, Leif

    1999-01-01

    The compressibility of nanostructured Fe-Cu materials prepared by mechanical milling has been investigated by in-situ high-pressure x-ray diffraction using synchrotron radiation. It is found that the bulk modulus of both fcc-Cu and bcc-Fe phases decreases with decreasing grain sizes. The unstable...... ferromagnetic fcc-FeCu solid solution prepared by mechanical alloying has a bulk modulus of about 85 GPa, which is much smaller than the corresponding values for bulk fcc-Cu and bcc-Fe....

  1. Nanostructured Functional Thermoplastic Polymeric Materials Based on the Molecular Control of the Blending

    Institute of Scientific and Technical Information of China (English)

    E.Passaglia; M.Bertoldo; S.Coiai; S.Augier; F.Ciardelli

    2007-01-01

    1 Results The development of the concepts of nanotechnology has given an important impact on the design of new polymer based materials which are in most cases characterized by a multiphase morphology. When at least one phase has nanometric dimension(s) the system can be considered as a nanocomposite where the interface is not only determining for the adhesion but also may play a role in some bulk properties. Indeed in nanostructured multiphase solids the interface is significant as a bulk component. The...

  2. A brief review on graphene/inorganic nanostructure composites: materials for the future

    Science.gov (United States)

    Mitra, S.; Banerjee, S.; Datta, A.; Chakravorty, D.

    2016-09-01

    The exotic physical properties of graphene have led to intense research activities on the synthesis and characterization of graphene composites during the last decade. The methods developed for preparation of such materials and the different application areas are reviewed. Mainly the inorganic nanostructure/graphene composites have been discussed. The techniques of ex-situ and in-situ hybridization respectively, have been pointed out. Some of the application areas such as batteries, ultracapacitors for energy storage, fuel cells and solar cells for energy generation are discussed. The possible future directions of research are highlighted.

  3. Probe beam deflection studies of nanostructured catalyst materials for fuel cells.

    Science.gov (United States)

    García, G; Bruno, M M; Planes, G A; Rodriguez, J L; Barbero, C A; Pastor, E

    2008-11-28

    Probe beam deflection (PBD) techniques, both as cyclic voltadeflectometry (CVD) and chronodeflectometry (CD), were applied for the first time to the study of the electrochemistry of nanostructured Pt materials which are commonly used as electrocatalysts in fuel cells. The electrochemical surface reactions, including faradaic processes, double layer charging and specific anion adsorption were easily detected. Quantitative analysis of the chronodeflectometric data made possible to elucidate the dynamics of double layer charging in such materials and to determine the potential of zero charge (pzc) of the metal present either as a monolithic mesoporous material or as metal nanoparticles supported on carbon. The electro-oxidation of CO, adsorbed on nanostructured Pt, was also studied by CVD and CD being able to detect the formation of CO2 and H3O+ related with the nucleation and growth process which controls the rate of CO stripping. The interplay of Pt oxide formation and COad electrooxidation, both in potential and time, was detected indicating possible application of the technique to other electrocatalysts.

  4. Nanostructured metal oxide-based materials as advanced anodes for lithium-ion batteries.

    Science.gov (United States)

    Wu, Hao Bin; Chen, Jun Song; Hng, Huey Hoon; Lou, Xiong Wen David

    2012-04-21

    The search for new electrode materials for lithium-ion batteries (LIBs) has been an important way to satisfy the ever-growing demands for better performance with higher energy/power densities, improved safety and longer cycle life. Nanostructured metal oxides exhibit good electrochemical properties, and they are regarded as promising anode materials for high-performance LIBs. In this feature article, we will focus on three different categories of metal oxides with distinct lithium storage mechanisms: tin dioxide (SnO(2)), which utilizes alloying/dealloying processes to reversibly store/release lithium ions during charge/discharge; titanium dioxide (TiO(2)), where lithium ions are inserted/deinserted into/out of the TiO(2) crystal framework; and transition metal oxides including iron oxide and cobalt oxide, which react with lithium ions via an unusual conversion reaction. For all three systems, we will emphasize that creating nanomaterials with unique structures could effectively improve the lithium storage properties of these metal oxides. We will also highlight that the lithium storage capability can be further enhanced through designing advanced nanocomposite materials containing metal oxides and other carbonaceous supports. By providing such a rather systematic survey, we aim to stress the importance of proper nanostructuring and advanced compositing that would result in improved physicochemical properties of metal oxides, thus making them promising negative electrodes for next-generation LIBs.

  5. Vertically Aligned Nanostructured Arrays of Inorganic Materials: Synthesis, Distinctive Physical Phenomena, and Device Integration

    Science.gov (United States)

    Velazquez, Jesus Manuel

    The manifestation of novel physical phenomena upon scaling materials to finite size has inspired new device concepts that take advantage of the distinctive electrical, mechanical, and optical, properties of nanostructures. The development of fabrication approaches for the preparation of their 1D nanostructured form, such as nanowires and nanotubes, has contributed greatly to advancing fundamental understanding of these systems, and has spurred the integration of these materials in novel electronics, photonic devices, power sources, and energy scavenging constructs. Significant progress has been achieved over the last decade in the preparation of ordered arrays of carbon nanotubes, II---VI and III---V semiconductors, and some binary oxides such as ZnO. In contrast, relatively less attention has been focused on layered materials with potential for electrochemical energy storage. Here, we describe the catalyzed vapor transport growth of vertical arrays of orthorhombic V2O 5 nanowires. In addition, near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is used to precisely probe the alignment, uniformity in crystal growth direction, and electronic structure of single-crystalline V2O5 nanowire arrays prepared by a cobalt-catalyzed vapor transport process. The dipole selection rules operational for core-level electron spectroscopy enable angle-dependant NEXAFS spectroscopy to be used as a sensitive probe of the anisotropy of these systems and provides detailed insight into bond orientation and the symmetry of the frontier orbital states. The experimental spectra are matched to previous theoretical predictions and allow experimental verification of features such as the origin of the split-off conduction band responsible for the n-type conductivity of V2O5 and the strongly anisotropic nature of vanadyl-oxygen-derived (V=O) states thought to be involved in catalysis. We have also invested substantial effort in obtaining shape and size control of metal oxide

  6. Synthesis and functional properties of nanostructured ceria materials; Synthese und funktionelle Eigenschaften nanostrukturierter Ceroxidmaterialien

    Energy Technology Data Exchange (ETDEWEB)

    Naumann, Meike

    2014-06-02

    Nanostructured ceria tubes have been synthesised using electro spun polymer fibers as templating material. These polymer mats are produced by electro spinning starting with a polymer solution. In a next step polymer fibers are decorated with cer containing sol, which is then dried. To receive ceria tubes the polymer is removed on the one hand by thermal decomposition of the polymer or on the other hand by oxygen plasma treatment of ceria/polymer hybrid material. The resulting ceria tubes have a specific surface area of 98 m2 g-1. TEM, XRD, SAED and Raman investigations show a fully nanostructured crystallinity with cubic fluorine type structure. This obtained material shows a photo catalytic activity within decomposition of methylene blue in the Vis part of the electromagnetic spectrum. This photo catalytic activity can be increased using doping ions of transition and rare earth elements that are introduced in the sol-gel synthesis. Also here XRD and TEM investigations show a fully nano crystalline structure of ceria. Raman spectroscopy verifies the doping of ceria by transition and rare earth elements up to 22% of doping. No phase separation can be observed. The photo catalytic activity can be increased using these doped materials. Additionally a catalytic activity of pure ceria and mixed ceria/zirconia materials have been investigated synthesis of dimethylcarboxilate without water addition. Here a direct dependence between turn over and doping cannot be detected. The dependence can be deduced to the synthesis process of the catalyst. Terminal sensoric properties of doped and undoped ceria (n-type semiconductor) are investigated. The prepared materials are used as chemiresistors against oxygen at temperatures of 700 C. These investigations show a reversible increase of the electrical resistance against oxygen.

  7. Dancing with Energetic Nitrogen Atoms: Versatile N-Functionalization Strategies for N-Heterocyclic Frameworks in High Energy Density Materials.

    Science.gov (United States)

    Yin, Ping; Zhang, Qinghua; Shreeve, Jean'ne M

    2016-01-19

    Nitrogen-rich heterocycles represent a unique class of energetic frameworks featuring high heats of formation and high nitrogen content, which have generated considerable research interest in the field of high energy density materials (HEDMs). Although traditional C-functionalization methodology of aromatic hydrocarbons has been fully established, studies on N-functionalization strategies of nitrogen-containing heterocycles still have great potential to be exploited by virtue of forming diverse N-X bonds (X = C, N, O, B, halogen, etc.), which are capable of regulating energy performance and the stability of the resulting energetic compounds. In this sense, versatile N-functionalization of N-heterocyclic frameworks offers a flexible strategy to meet the requirements of developing new-generation HEDMs. In this Account, the role of strategic N-functionalization in designing new energetic frameworks, including the formation of N-C, N-N, N-O, N-B and N-halogen bonds, is emphasized. In the family of N-functionalized HEDMs, energetic derivatives, by virtue of forming N-C bonds, are the most widely used type due to the good nucleophilic capacity of most heterocyclic backbones. Although introduction of carbon tends to decrease energetic performance, significant improvement in material sensitivity makes this strategy attractive for safety concerns. More importantly, most "explosophores" can be readily introduced into the N-C linkage, thus providing a promising route to various HEDMs. Formation of additional N-N bonds typically gives rise to higher heats of formation, implying the potential enhancement in detonation performance. In many cases, the increased hydrogen bonding interactions within N-N functionalized heterocycles also improve thermal stability accordingly. Introduction of a single N,N'-azo bridge into several azole moieties leads to an extended nitrogen chain, demonstrating a new strategy for designing high-nitrogen compounds. The strategy of N-O functionalization

  8. QSPR modeling of detonation parameters and sensitivity of some energetic materials: DFT vs. PM3 calculations.

    Science.gov (United States)

    Zhang, Jianying; Chen, Gangling; Gong, Xuedong

    2017-06-01

    The quantitative structure-property relationship (QSPR) methodology was applied to describe and seek the relationship between the structures and energetic properties (and sensitivity) for some common energy compounds. An extended series of structural and energetic descriptors was obtained with density functional theory (DFT) B3LYP and semi-empirical PM3 approaches. Results indicate that QSPR model constructed using quantum descriptors can be applied to verify the confidence of calculation results compared with experimental data. It can be extended to predict the properties of similar compounds.

  9. The process of nanostructuring of metal (iron) matrix in composite materials for directional control of the mechanical properties.

    Science.gov (United States)

    Zemtsova, Elena; Yurchuk, Denis; Smirnov, Vladimir

    2014-01-01

    We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1) preparation of porous metal matrix; (2) surface structuring of the porous metal matrix by TiC nanowires; (3) pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1-50 nm. This material can be represented as the material type "frame in the frame" that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based) materials with improved mechanical properties for the different areas of technology.

  10. The Process of Nanostructuring of Metal (Iron Matrix in Composite Materials for Directional Control of the Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Elena Zemtsova

    2014-01-01

    Full Text Available We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1 preparation of porous metal matrix; (2 surface structuring of the porous metal matrix by TiC nanowires; (3 pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1–50 nm. This material can be represented as the material type “frame in the frame” that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based materials with improved mechanical properties for the different areas of technology.

  11. Self-assembly strategies for the synthesis of functional nanostructured materials

    Science.gov (United States)

    Perego, M.; Seguini, G.

    2016-06-01

    Self-assembly is the autonomous organization of components into patterns or structures without human intervention. This is the approach followed by nature to generate living cells and represents one of the practical strategies to fabricate ensembles of nanostructures. In static self-assembly the formation of ordered structures could require energy but once formed the structures are stable. The introduction of additional regular features in the environment could be used to template the self-assembly guiding the organization of the components and determining the final structure they form. In this regard self-assembly of block copolymers represents a potent platform for fundamental studies at the nanoscale and for application-driven investigation as a tool to fabricate functional nanostructured materials. Block copolymers can hierarchically assemble into chemically distinct domains with size and periodicity on the order of 10nm or below, offering a potentially inexpensive route to generate large-area nanostructured materials. The final structure characteristics of these materials are dictated by the properties of the elementary block copolymers, like chain length, volume fraction or degree of block incompatibility. Modern synthetic chemistry offers the possibility to design these macromolecules with very specific length scales and geometries, directly embodying in the block copolymers the code that drives their self- assembling process. The understanding of the kinetics and thermodynamics of the block copolymer self-assembly process in the bulk phase as well as in thin films represents a fundamental prerequisite toward the exploitation of these materials. Incorporating block copolymer into device fabrication procedures or directly into devices, as active elements, will lead to the development of a new generation of devices fabricated using the fundamental law of nature to our advantage in order to minimize cost and power consumption in the fabrication process

  12. Surface modification of plasmonic nanostructured materials with thiolated oligonucleotides in 10 seconds using selective microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Abel, B.; Aslan, K. [Morgan State University, Department of Chemistry, 1700 East Cold Spring Lane, Baltimore, MD 21251 (United States)

    2012-11-15

    This study demonstrates the proof-of-principle of rapid surface modification of plasmonic nanostructured materials with oligonucleotides using low power microwave heating. Due to their interesting optical and electronic properties, silver nanoparticle films (SNFs, 2 nm thick) deposited onto glass slides were used as the model plasmonic nanostructured materials. Rapid surface modification of SNFs with oligonucleotides was carried out using two strategies (1) Strategy 1: for ss-oligonucleotides, surface hybridization and (2) Strategy 2: for ds-oligonucleotides, solution hybridization, where the samples were exposed to 10, 15, 30 and 60 seconds microwave heating. To assess the efficacy of our new rapid surface modification technique, identical experiments carried out without the microwave heating (i.e., conventional method), which requires 24 hours for the completion of the identical steps. It was found that SNFs can be modified with ss- and ds-oligonucleotides in 10 seconds, which typically requires several hours of incubation time for the chemisorption of thiol groups on to the planar metal surface using conventional techniques. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Quick preparation and thermal transport properties of nanostructured β-FeSi2 bulk material

    Institute of Scientific and Technical Information of China (English)

    Li Han; Tang Xin-Feng; Cao Wei-Qiang; Zhang Qing-Jie

    2009-01-01

    This paper reports that the nanostructured β-FeSi2 bulk materials are prepared by a new synthesis process by combining melt spinning (MS) and subsequent spark plasma sintering (SPS). It investigates the influence of linear speed of the rolling copper wheel, injection pressure and SPS regime on microstructure and phase composition of the rapidly solidified ribbons after MS and bulk production respectively, and discusses the effects of the microstructure on Sis2 and ε-FeSi) in the rapidly solidified ribbons;thermal transport properties. There are two crystalline phases (α-Fe the crystal grains become smaller when the cooling rate increases (the 20 nm minimum crystal of ε-FeSi is obtained). Having been sintered for 1 min above 1123K and annealed for 5min at 923K, the single-phase nanostructured β- FeSi2 bulk materials with 200-500 nm grain size and 98% relative density are obtained. The microstructure of β-FeSi2has great effect on thermal transport properties. With decreasing sintering temperature, the grain size decreases, the thermal conductivity of β-FeSi2is reduced remarkably. The thermal conductivity of β-FeSi decreases notably (reduced 72% at room temperature) in comparison with the β-FeSi2prepared by traditional casting method.

  14. Simultaneous measurement of orientational and spectral dynamics of single molecules in nanostructured host-guest materials.

    Science.gov (United States)

    Jung, Christophe; Hellriegel, Christian; Platschek, Barbara; Wöhrle, Dieter; Bein, Thomas; Michaelis, Jens; Bräuchle, Christoph

    2007-05-02

    Nanostructured host-guest materials are important for various applications in nanoscience, and therefore, a thorough understanding of the dynamics of the guest molecules within the host matrix is needed. To this aim we used single-molecule fluorescence techniques to simultaneously examine the spectral and the orientational behavior of single molecules in nanostructured porous host materials. Two types of host-guest systems have been investigated. First, oxazine-1 dye molecules were fixed rigidly in the channels of microporous AlPO4-5 crystals. Second, it was shown that terrylenediimide (TDI) dye molecules move in the mesoporous network of an uncalcined M41S thin film. In the first sample both spectral fluctuations ( approximately 5 nm) and rare spectral jumps (>10 nm) of the emission maximum were observed. However, the orientation of the emission dipole of the dye molecules remained constant. In contrast, the second system showed orientational dynamics as well as substantially more spectral dynamics. In this system the molecules were found to move between different regions in the host. The typical motion of the TDI molecules in the pores of M41S was not continuous but characterized by jumps between specific sites. Moreover, the spectral and orientational dynamics were correlated and arose directly from the different environments that were being explored by the mobile molecule.

  15. Nanostructured materials on 3D nickel foam as electrocatalysts for water splitting.

    Science.gov (United States)

    Chaudhari, Nitin K; Jin, Haneul; Kim, Byeongyoon; Lee, Kwangyeol

    2017-08-31

    Highly efficient and low-cost electrocatalysts are essential for water spitting via electrolysis in an economically viable fashion. However, the best catalytic performance is found with noble metal-based electrocatalysts, which presents a formidable obstacle for the commercial success of electrolytic water splitting-based H2 production due to their relatively high cost and scarcity. Therefore, the development of alternative inexpensive earth-abundant electrode materials with excellent electrocatalytic properties is of great urgency. In general, efficient electrocatalysts must possess several key characteristics such as low overpotential, good electrocatalytic activity, high stability, and low production costs. Direct synthesis of nanostructured catalysts on a conducting substrate may potentially improve the performance of the resultant electrocatalysts because of their high catalytic surface areas and the synergistic effect between the electrocatalyst and the conductive substrate. In this regard, three dimensional (3D) nickel foams have been advantageously utilized as electrode substrates as they offer a large active surface area and a highly conductive continuous porous 3D network. In this review, we discuss the most recent developments in nanostructured materials directly synthesized on 3D nickel foam as potential electrode candidates for electrochemical water electrolysis, namely, the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). We also provide perspectives and outlooks for catalysts grown directly on 3D conducting substrates for future sustainable energy technologies.

  16. 3,6-Dinitropyrazolo[4,3-c]pyrazole-Based Multipurpose Energetic Materials through Versatile N-Functionalization Strategies.

    Science.gov (United States)

    Yin, Ping; Zhang, Jiaheng; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

    2016-10-04

    A family of 3,6-dinitropyrazolo[4,3-c]pyrazole-based energetic compounds was synthesized by using versatile N-functionalization strategies. Subsequently, nine ionic derivatives of the N,N'-(3,6-dinitropyrazolo[4,3-c]pyrazole-1,4-diyl)dinitramidate anion were prepared by acid-base reactions and fully characterized by infrared, multinuclear NMR spectra, and elemental analysis. The structures of four of these compounds were further confirmed by single-crystal X-ray diffraction. Based on their different physical and detonation properties, these compounds exhibit promising potential as modern energetic materials and can be variously classified as green primary explosives, high-performance secondary explosives, fuel-rich propellants, and propellant oxidizers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Measurement and modeling of energetic-material mass transfer to soil-pore water - Project CP-1227 final technical report.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua S.; Sallaberry, Cedric M.; Webb, Stephen Walter; Phelan, James M.; Hadgu, Teklu

    2006-05-01

    Military test and training ranges operate with live-fire engagements to provide realism important to the maintenance of key tactical skills. Ordnance detonations during these operations typically produce minute residues of parent explosive chemical compounds. Occasional low-order detonations also disperse solid-phase energetic material onto the surface soil. These detonation remnants are implicated in chemical contamination impacts to groundwater on a limited set of ranges where environmental characterization projects have occurred. Key questions arise regarding how these residues and the environmental conditions (e.g., weather and geostratigraphy) contribute to groundwater pollution. This final report documents the results of experimental and simulation model development for evaluating mass transfer processes from solid-phase energetics to soil-pore water.

  18. Asymmetrically substituted 5,5'-bistriazoles--nitrogen-rich materials with various energetic functionalities.

    Science.gov (United States)

    Dippold, Alexander A; Klapötke, Thomas M; Oswald, Michaela

    2013-08-21

    In this contribution the synthesis and full structural and spectroscopic characterization of three asymmetrically substituted bis-1,2,4-triazoles, along with different energetic moieties like amino, nitro, nitrimino and azido moieties, is presented. Additionally, selected nitrogen-rich ionic derivatives have been prepared and characterized. This comparative study on the influence of these energetic moieties on structural and energetic properties constitutes a complete characterization including IR, Raman and multinuclear NMR spectroscopy. Single crystal X-ray crystallographic measurements were performed and provide insight into structural characteristics as well as inter- and intramolecular interactions. The standard enthalpies of formation were calculated for all compounds at the CBS-4M level of theory, revealing highly positive heats of formation for all compounds. The detonation parameters were calculated using the EXPLO5 program and compared to the common secondary explosive RDX as well as recently published symmetric bistriazoles. As expected, the measured sensitivities to mechanical stimuli and decomposition temperatures strongly depend on the energetic moiety of the triazole ring. All compounds were characterized in terms of sensitivities (impact, friction, electrostatic) and thermal stabilities, the ionic derivatives were found to be thermally stable, insensitive compounds.

  19. Leading research on super metal. 3. Amorphous and nanostructured metallic materials; Super metal no sendo kenkyu. 3. Kogata buzai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Very fine structure control technique for amorphous and nanostructured metallic materials was reviewed to exceed the marginal performance of small metallic member materials. In Japan, high strength alloys and anticorrosion alloys are currently developed as an amorphous structure control technique, and ultra fine powder production and nano-compaction molding are studied for nanostructured materials. Fabrication of amorphous alloy wire materials and metal glass in USA are also introduced. Fabrication of metallic nanocrystals deposited within gas phase in Germany are attracting attention. The strength and abrasion resistance are remarkably enhanced by making nanostructured crystals and dispersing them. It may be most suitable to utilize amorphous and nanostructured metallic materials for earth-friendly materials having anticorrosion, and catalyst and biomaterial affinities, and also for magnetic materials. It is important for controlling micro-structures to clarify the formation mechanism of structures. For their processing techniques, the diversity and possibility are suggested, as to the condensation and solidification of gaseous and liquid phase metals, the molding and processing of very fine solid phase alloys, and the manufacturing members by heat treatment. 324 refs., 109 figs., 21 tabs.

  20. Center for Fundamental and Applied Research in Nanostructured and Lightweight Materials. Final Technical Summary

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, Michael; Rogers, Tony; King, Julia; Keith, Jason; Cornilsen, Bahne; Allen, Jeffrey; Gilbert, Ryan; Holles, Joseph

    2010-09-28

    The core projects for this DOE-sponsored Center at Michigan Tech have focused on several of the materials problems identified by the NAS. These include: new electrode materials, enhanced PEM materials, lighter and more effective bipolar plates, and improvement of the carbon used as a current carrier. This project involved fundamental and applied research in the development and testing of lightweight and nanostructured materials to be used in fuel cell applications and for chemical synthesis. The advent of new classes of materials engineered at the nanometer level can produce materials that are lightweight and have unique physical and chemical properties. The grant was used to obtain and improve the equipment infrastructure to support this research and also served to fund seven research projects. These included: 1. Development of lightweight, thermally conductive bipolar plates for improved thermal management in fuel cells; 2. Exploration of pseudomorphic nanoscale overlayer bimetallic catalysts for fuel cells; 3. Development of hybrid inorganic/organic polymer nanocomposites with improved ionic and electronic properties; 4. Development of oriented polymeric materials for membrane applications; 5. Preparation of a graphitic carbon foam current collectors; 6. The development of lightweight carbon electrodes using graphitic carbon foams for battery and fuel cell applications; and 7. Movement of water in fuel cell electrodes.

  1. Ultra-strong and damage tolerant metallic bulk materials: A lesson from nanostructured pearlitic steel wires.

    Science.gov (United States)

    Hohenwarter, A; Völker, B; Kapp, M W; Li, Y; Goto, S; Raabe, D; Pippan, R

    2016-09-14

    Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today's strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material's strength.

  2. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    Science.gov (United States)

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-02-06

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  3. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

    Directory of Open Access Journals (Sweden)

    Kateryna Shavanova

    2016-02-01

    Full Text Available The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical. A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  4. Electrical, thermal, catalytic and magnetic properties of nano-structured materials and their applications

    Science.gov (United States)

    Liu, Zuwei

    Nanotechnology is a subject that studies the fabrication, properties, and applications of materials on the nanometer-scale. Top-down and bottom-up approaches are commonly used in nano-structure fabrication. The top-down approach is used to fabricate nano-structures from bulk materials by lithography, etching, and polishing etc. It is commonly used in mechanical, electronic, and photonic devices. Bottom-up approaches fabricate nano-structures from atoms or molecules by chemical synthesis, self-assembly, and deposition, such as sol-gel processing, molecular beam epitaxy (MBE), focused ion beam (FIB) milling/deposition, chemical vapor deposition (CVD), and electro-deposition etc. Nano-structures can have several different dimensionalities, including zero-dimensional nano-structures, such as fullerenes, nano-particles, quantum dots, nano-sized clusters; one-dimensional nano-structures, such as carbon nanotubes, metallic and semiconducting nanowires; two-dimensional nano-structures, such as graphene, super lattice, thin films; and three-dimensional nano-structures, such as photonic structures, anodic aluminum oxide, and molecular sieves. These nano-structured materials exhibit unique electrical, thermal, optical, mechanical, chemical, and magnetic properties in the quantum mechanical regime. Various techniques can be used to study these properties, such as scanning probe microscopy (SPM), scanning/transmission electron microscopy (SEM/TEM), micro Raman spectroscopy, etc. These unique properties have important applications in modern technologies, such as random access memories, display, solar energy conversion, chemical sensing, and bio-medical devices. This thesis includes four main topics in the broad area of nanoscience: magnetic properties of ferro-magnetic cobalt nanowires, plasmonic properties of metallic nano-particles, photocatalytic properties of titanium dioxide nanotubes, and electro-thermal-optical properties of carbon nanotubes. These materials and their

  5. Initial mechanisms for the unimolecular decomposition of electronically excited bisfuroxan based energetic materials.

    Science.gov (United States)

    Yuan, Bing; Bernstein, Elliot R

    2017-01-07

    Unimolecular decomposition of energetic molecules, 3,3'-diamino-4,4'-bisfuroxan (labeled as A) and 4,4'-diamino-3,3'-bisfuroxan (labeled as B), has been explored via 226/236 nm single photon laser excitation/decomposition. These two energetic molecules, subsequent to UV excitation, create NO as an initial decomposition product at the nanosecond excitation energies (5.0-5.5 eV) with warm vibrational temperature (1170 ± 50 K for A, 1400 ± 50 K for B) and cold rotational temperature (energetic barrier is that for which the furoxan ring opens on the S1 state via the breaking of the N1-O1 bond. Subsequently, the molecule moves to the ground S0 state through related ring-opening conical intersections, and an NO product is formed on the ground state surface with little rotational excitation at the last NO dissociation step. For the ground state ring opening decomposition mechanism, the N-O bond and C-N bond break together in order to generate dissociated NO. With the MP2 correction for the CASSCF(12,12) surface, the potential energies of molecules with dissociated NO product are in the range from 2.04 to 3.14 eV, close to the theoretical result for the density functional theory (B3LYP) and MP2 methods. The CASMP2(12,12) corrected approach is essential in order to obtain a reasonable potential energy surface that corresponds to the observed decomposition behavior of these molecules. Apparently, highly excited states are essential for an accurate representation of the kinetics and dynamics of excited state decomposition of both of these bisfuroxan energetic molecules. The experimental vibrational temperatures of NO products of A and B are about 800-1000 K lower than previously studied energetic molecules with NO as a decomposition product.

  6. Zero-dimensional nanostructured material with metallic bismuth nanoparticles: a new route for thermoelectrics

    Science.gov (United States)

    Benoit, Roland; Treguer, Mona; Saboungi, Marie-Louise

    2011-03-01

    The thermoelectric figure of merit ZT has so far not exceeded the value ZT=3 need to compete with mechanical energy conversion systems. However, theoretical work has shown that it is possible to reach values of ZT higher than this. One of the most promising routes is nanostructured materials, which offer the opportunity to tailor physical properties such as electrical and heat transport, due to the effects of electron filtering and phonon confinement. Dresselhaus et al. (ref.?) were among the first to show that 2D and 1D structures are capable of reaching ZT values higher than 2. The thermoelectric materials of current interest are in the form of nanotubes, nanodots and, more generally, superlattices composed of a matrix and nanoparticles. In our work we synthesize a periodic network of bismuth nanoparticles in a matrix of mesoporous Si O2 . We find that in this form bismuth transforms from a rhombohedral to a cubic structure, with improved filtering of electrons and phonons.

  7. Synchrotron SAXS Studies of Nanostructured Materials and Colloidal Solutions: A Review

    Directory of Open Access Journals (Sweden)

    Craievich A.F.

    2002-01-01

    Full Text Available Structural characterisations using the SAXS technique in a number of nanoheterogeneous materials and liquid solutions are reviewed. The studied systems are protein (lysozyme/water solutions, colloidal ZnO particles/water sols, nanoporous NiO-based xerogels, hybrid organic-inorganic siloxane-PEG and PPG nanocomposites and PbTe semiconductor nanocrystals embedded in a glass matrix. These investigations also focus on the transformations of time-varying structures and on structural changes related to variations in temperature and composition. The reviewed investigations aim at explaining the unusual and often interesting properties of nanostructured materials and solutions. Most of the reported studies were carried out using the SAXS beamline at the National Synchrotron Light Laboratory (LNLS, Campinas, Brazil.

  8. Ultrathin Two-Dimensional Nanostructured Materials for Highly Efficient Water Oxidation.

    Science.gov (United States)

    Zhang, Wang; Zhou, Kun

    2017-08-01

    Water oxidation, also known as the oxygen evolution reaction (OER), is a crucial process in energy conversion and storage, especially in water electrolysis. The critical challenge of the electrochemical water splitting technology is to explore alternative precious-metal-free catalysts for the promotion of the kinetically sluggish OER. Recently, emerging two-dimensional (2D) ultrathin materials with abundant accessible active sites and improved electrical conductivity provide an ideal platform for the synthesis of promising OER catalysts. This Review focuses on the most recent advances in ultrathin 2D nanostructured materials for enhanced electrochemical activity of the OER. The design, synthesis and performance of such ultrathin 2D nanomaterials-based OER catalysts and their property-structure relationships are discussed, providing valuable insights to the exploration of novel OER catalysts with high efficiency and low overpotential. The potential research directions are also proposed in the research field. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Laser Photolysis and Thermolysis of Organic Selenides and Tellurides for Chemical Gas-phase Deposition of Nanostructured Materials

    Directory of Open Access Journals (Sweden)

    Josef Pola

    2009-03-01

    Full Text Available Laser radiation-induced decomposition of gaseous organic selenides and tellurides resulting in chemical deposition of nanostructured materials on cold surfaces is reviewed with regard to the mechanism of the gas-phase decomposition and properties of the deposited materials. The laser photolysis and laser thermolysis of the Se and Te precursors leading to chalcogen deposition can also serve as a useful approach to nanostructured chalcogen composites and IVA group (Si, Ge, Sn element chalcogenides provided that it is carried out simultaneously with laser photolysis or thermolysis of polymer and IVA group element precursor.

  10. Laser photolysis and thermolysis of organic selenides and tellurides for chemical gas-phase deposition of nanostructured materials.

    Science.gov (United States)

    Pola, Josef; Ouchi, Akihiko

    2009-03-12

    Laser radiation-induced decomposition of gaseous organic selenides and tellurides resulting in chemical deposition of nanostructured materials on cold surfaces is reviewed with regard to the mechanism of the gas-phase decomposition and properties of the deposited materials. The laser photolysis and laser thermolysis of the Se and Te precursors leading to chalcogen deposition can also serve as a useful approach to nanostructured chalcogen composites and IVA group (Si, Ge, Sn) element chalcogenides provided that it is carried out simultaneously with laser photolysis or thermolysis of polymer and IVA group element precursor.

  11. Ultra-strong and damage tolerant metallic bulk materials: A lesson from nanostructured pearlitic steel wires

    Science.gov (United States)

    Hohenwarter, A.; Völker, B.; Kapp, M. W.; Li, Y.; Goto, S.; Raabe, D.; Pippan, R.

    2016-09-01

    Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today’s strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material’s strength.

  12. Thermoelectric properties and nanostructures of materials prepared from rice husk ash

    Energy Technology Data Exchange (ETDEWEB)

    Pukird, S.; Tipparach, U.; Kasian, P. [Ubon Ratchathani Univ., Ubon Ratchathani (Thailand). Dept. of Physics; Limsuwan, P. [King Mongkut' s Univ. of Technology Thonburi, Bangkok (Thailand). Dept. of Physics

    2009-07-01

    Thailand produces large amounts of agricultural residues such as rice husk and coconut shells. Rice husk is considered to be a potential source for solar grade silicon. Studies have shown that reasonably pure polycrystalline silicon can be prepared from rice husk white ash by a metallothermic reduction process. This paper reported on a study that investigated the thermoelectric properties of ceramic material prepared by mixing silica from rice husk ash and carbon obtained from coconut shell charcoal. The thermoelectric properties of the materials were examined along with their microstructures. The materials were made from burning rice husk ash and coconut shell at different temperatures and then doped with metal oxides. Pellets were heated at temperature of 700 degrees C for 1-3 hours. The voltage on both sides of the pellets was observed. The electromotive force was found when different temperatures were applied on both sides of the pellet specimens. The Seebeck coefficient was then calculated. The results showed that these materials can be used as thermoelectric devices. Scanning electron microscope (SEM) and energy dispersive X-rays (EDX) were used to investigate the source of materials and the products on the substrates. The images of SEM and EDX showed nanostructures of materials such as nanowires, nanorods and nanoparticles of the products and sources. 22 refs., 2 tabs., 9 figs.

  13. Controllable preparation of CeO2 nanostructure materials and their catalytic activity

    Institute of Scientific and Technical Information of China (English)

    Shan Wenjuan; Guo Hongjuan; Liu Chang; Wang Xiaonan

    2012-01-01

    Well-crystalline CeO2 nanostructures with the morphology ofnanorods and nanocubes were synthesized by a template-free hydrothermal method.X-ray diffraction (XRD),transmission electron microscopy (TEM),Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption measurements were employed to characterize the synthesized materials.The reducibility and catalytic activity of nanostructured CeO2 were examined by hydrogen temperature-programmed reduction (H2-TPR) and CO oxidation.The results showed that CeO2 nanorods could be converted into CeO2 nanocubes with the increasing of the reaction time and the hydrothermal temperature,CeO2 nanorods became longer gradually with the increasing of the concentrations of NaOH.H2-TPR characterization demonstrated that the intense low-temperature reduction peak in the CeO2 nanorods indicated the amount of hydrogen consumed is larger than CeO2 nanocubes.Meantime the CeO2 nanorods enhanced catalytic activity for CO oxidation,the total conversion temperature was 340 ℃.The reasons were that CeO2 nanorods have much smaller crystalline sizes and higher surface areas than CeO2 nanocubes.

  14. Interfacial engineering of two-dimensional nano-structured materials by atomic layer deposition

    Science.gov (United States)

    Zhuiykov, Serge; Kawaguchi, Toshikazu; Hai, Zhenyin; Karbalaei Akbari, Mohammad; Heynderickx, Philippe M.

    2017-01-01

    Atomic Layer Deposition (ALD) is an enabling technology which provides coating and material features with significant advantages compared to other existing techniques for depositing precise nanometer-thin two-dimensional (2D) nanostructures. It is a cyclic process which relies on sequential self-terminating reactions between gas phase precursor molecules and a solid surface. ALD is especially advantageous when the film quality or thickness is critical, offering ultra-high aspect ratios. ALD provides digital thickness control to the atomic level by depositing film one atomic layer at a time, as well as pinhole-free films even over a very large and complex areas. Digital control extends to sandwiches, hetero-structures, nano-laminates, metal oxides, graded index layers and doping, and it is perfect for conformal coating and challenging 2D electrodes for various functional devices. The technique's capabilities are presented on the example of ALD-developed ultra-thin 2D tungsten oxide (WO3) over the large area of standard 4" Si substrates. The discussed advantages of ALD enable and endorse the employment of this technique for the development of hetero-nanostructure 2D semiconductors with unique properties.

  15. Recent advances in MoS2 nanostructured materials for energy and environmental applications - A review

    Science.gov (United States)

    Theerthagiri, J.; Senthil, R. A.; Senthilkumar, B.; Reddy Polu, Anji; Madhavan, J.; Ashokkumar, Muthupandian

    2017-08-01

    Molybdenum disulfide (MoS2), a layered transition metal dichalcogenide with an analogous structure to graphene, has attracted enormous attention worldwide owing to its use in a variety of applications such as energy storage, energy conversion, environmental remediation and sensors. MoS2 and graphene have almost similar functional properties such as high charge carrier transport, high wear resistance and good mechanical strength and friction. However, MoS2 is advantageous over graphene due to its low-cost, abundancy, tailorable morphologies and tuneable band gap with good visible light absorption properties. In this review, we have focussed mainly on recent advances in MoS2 nanostructured materials for the applications in the broad area of energy and environment. Special attention has been paid to their applications in dye-sensitized solar cells, supercapacitor, Li-ion battery, hydrogen evolution reaction, photocatalysis for the degradation of organic pollutants, chemical/bio sensors and gas sensors. Finally, the challenges to design MoS2 nanostructures suitable for energy and environmental applications are also highlighted.

  16. Efficient dual mode multicolor luminescence in a lanthanide doped hybrid nanostructure: a multifunctional material.

    Science.gov (United States)

    Singh, S K; Singh, A K; Rai, S B

    2011-07-08

    The present work deals with inorganic-organic hybrid nanostructures capable of producing intense visible emission via upconversion (UC), downconversion (DC), and energy transfer (ET) processes which show the potential of the material as a luminescent solar collector (LSC), particularly to improve the efficiency of silicon solar cells. To achieve this, Gd2O3:Yb3+/Er3+ phosphor (average particle size∼35 nm) and a Eu(DBM)3Phen organic complex have been synthesized separately and then the hybrid structure has been developed using a simple mixing procedure. Intense UC emission (in the red, green, and blue regions) due to Er3+ is observed on near infrared (976 nm) excitation which shows color tunability with input pump power. In contrast, intense red emission of Eu3+ is observed on ultaviolet (UV) (355 nm) excitation. The feasibility of energy transfer from Er3+ ions to Eu3+ ions has also been noted. These excellent optical properties are retained even if the particles of the hybrid nanostructure are dispersed in liquid medium, which also makes it suitable for security ink purposes.

  17. Sorptive removal of trinitroglycerin (TNG) from water using nanostructured silica-based materials.

    Science.gov (United States)

    Saad, Rabih; Thibutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2010-01-01

    Trinitroglycerin (TNG), a nitrate ester, is widely used in the pharmaceutical industry for the treatment of angina pectoris (chest pain) and by the military for the manufacturing of dynamite and propellants. Currently, TNG is considered as a key environmental contaminant due to the discharge of wastewater tainted with the chemical from various military and pharmaceutical industries. The present study describes the use of a nanostructured silica material (Mobil Composite Material no. 48 [MCM-48]) prepared by mixing tetraethylorthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) to remove TNG from water. The sorption of TNG onto MCM-48 rapidly reached equilibrium within 1 h. Sorption kinetics were best described using a pseudo-second order model, whereas sorption isotherms were best interpreted using the Langmuir model. The latter gave a maximum sorption capacity of 55.2 mg g(-1) at 40 degrees C. The enthalpy and entropy of TNG sorption onto MCM-48 were 1.89 kJ mol(-1) and 79.0 J mol(-1).K(-1), indicating the endothermic nature of the TNG sorption onto MCM-48. When MCM-48 was heated at 540 degrees C for 5 h, the resulting calcined material (absence of the surfactant) did not sorb TNG, suggesting that the surfactant component of the nanomaterial was responsible for TNG sorption. Finally, we found that MCM-48 lost approximately 30% of its original sorption capacity after five sorption-desorption cycles. In conclusion, the nanostructured silica based sorbent, with high sorption capacity and remarkable reusability, should constitute the basis for the development of an effective technology for the removal of TNG from contaminated water.

  18. Bioinspired High-Performance Energetic Materials Using Heme-Containing Crystals.

    Science.gov (United States)

    Slocik, Joseph M; Drummy, Lawrence F; Dickerson, Matthew B; Crouse, Christopher A; Spowart, Jonathan E; Naik, Rajesh R

    2015-08-05

    Synthetic hemozoin crystals (β-hematin) are assembled with aluminium nanoparticles (nAl) to create a nanomaterial composite that is highly energetic and reactive. The results here demonstrate that hemozoin rapidly oxidizes the nAl fuel to release large amounts of energy (+12.5 ± 2.4 kJ g(-1) ). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Carbon fiber CVD coating by carbon nanostructured for space materials protection against atomic oxygen

    Science.gov (United States)

    Pastore, Roberto; Bueno Morles, Ramon; Micheli, Davide

    2016-07-01

    adhesion and durability in the environment. Though these coatings are efficient in protecting polymer composites, their application imposes severe constraints. Their thermal expansion coefficients may differ markedly from those of polymer composite substrates: as a result, cracks develop in the coatings on thermal cycling and AO can penetrate through them to the substrate. In addition to the technicalities of forming an effective barrier, such factors as cost, convenience of application and ease of repair are important considerations in the selection of a coating for a particular application. The latter issues drive the aerospace research toward the development of novel light composite materials, like the so called polymer nanocomposites, which are materials with a polymer matrix and a filler with at least one dimension less than 100 nanometers. Current interest in nanocomposites has been generated and maintained because nanoparticle-filled polymers exhibit unique combinations of properties not achievable with traditional composites. These combinations of properties can be achieved because of the small size of the fillers, the large surface area the fillers provide, and in many cases the unique properties of the fillers themselves. In particular, the carbon fiber-based polymeric composite materials are the basic point of interest: the aim of the present study is to find new solution to produce carbon fiber-based composites with even more upgraded performances. One intriguing strategy to tackle such an issue has been picked out in the coupling between the carbon fibers and the carbon nanostructures. That for two main reasons: first, carbon nanostructures have shown fancy potentialities for any kind of technological applications since their discovery, second, the chemical affinity between fiber and nanostructure (made of the same element) should be a likely route to approach the typical problems due to thermo-mechanical compatibility. This work is joined in such framework

  20. Theory of light propagation in nano-structured materials and semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Schaarschmidt, M.

    2006-05-03

    This work presents a theory for the propagation of intense electromagnetic radiation in nano-structures materials and semiconductors. One main area is the modelling and simulation of the microscopic material dynamics of low dimensional semiconductors, both structured and bulk, and of a laser induced plasma. The ultrafast microscopic dynamics of these electronic many particle systems under the influence of light fields and scattering mechanisms like electron-electron interaction or interaction with lattice vibrations is described in the density matrix formalism. This description in second quantization yields the temporal nonlocal and nonlinear response of the material to electromagnetic fields. Laser induced plasma in quantum wells will be shown to be a possible new semiconductor source for terahertz-emission (wavelength mm to micrometer). The second focus of interest of this work lies in the simulation of the propagation of electromagnetic waves in different systems like photonic crystals, optical fibers and wave guides. The propagation in bulk semiconductors and waveguides is considered in both slowly varying envelope approximation (SVEA) and with the nonlinear Schroedinger equation. For complex systems like photonic band gap structures with high symmetry a matrix-transfer formalism is applied. For arbitrary structured systems (which may include local breaches of symmetry) a very flexible finite-differences algorithm is employed. The combination of microscopic material dynamics and light propagation enables the calculation of reflection and transmission properties of nano-structured materials not only in linear excitation but also for high intensities where nonlinear light-matter coupling dominates and novel effects arise. One used model system are Bragg-resonant multiple quantum wells. On this one dimensional resonant absorbing photonic crystal new nonlinear effects are studied. Some effect to mention are the possible application as an ultrafast optical switch

  1. Computational and Experimental Study of Energetic Materials in a Counterflow Microgravity Environment

    Science.gov (United States)

    Takahashi, Fumiaki (Technical Monitor); Urban, David (Technical Monitor); Smooke, M. D.; Parr, T. P.; Hanson-Parr, D. M.; Yetter, R. A.; Risha, G.

    2004-01-01

    thermal wave penetration into the liquid, these experiments were found feasible, but not used for obtaining quantitative data. Microgravity experiments are needed to eliminate the dripping and boiling phenomena of these systems at normal gravity. Microgravity tests in the NASA Glenn 2.2 second drop tower were performed (1) to demonstrate the feasibility of performing propellant experiments using the NASA Glenn microgravity facilities, (2) to develop the operational procedures for safe handing of the energetic materials and disposal of their toxic combustion by-products and (3) to obtain initial measurements of the AP burning rate and flame structure under microgravity conditions. Experiments were conducted on the CH4/AP system previously studied at normal gravity using a modified design of the counterflow burner and a NASA Glenn Pig Rig, i.e., one of the existing drop rigs for general-purpose usage. In these experiments, the AP burning rate was measured directly with a linear variable differential transducer (LVDT) and video imaging of the flame structure was recorded ignition was achieved by hot wires stretched across the AP surfaces. Initial drop tower combustion data show that with the same burner separation distance and flow conditions of the normal gravity experiments, the AP burning rate is approximately a factor of two lower. This difference is likely a result of radiation effects, but further tests with longer test times need to be conducted to verify that steady state conditions were achieved under microgravity conditions.

  2. Nitramino- and Dinitromethyl-Substituted 1,2,4-Triazole Derivatives as High-Performance Energetic Materials.

    Science.gov (United States)

    Tang, Yongxing; Dharavath, Srinivas; Imler, Gregory H; Parrish, Damon A; Shreeve, Jean'ne M

    2017-07-06

    Since highly nitrated nitrogen-rich heterocycles are important motifs in high energy density materials, extensive studies for the development of such novel molecules have been underway. A highly energetic moiety, 3-dinitromethyl-5-nitramino-1,2,4-triazole, which consists of a triazole ring, and nitramino and dinitromethyl groups, has been designed and synthesized. By pairing with nitrogen-rich cations, several ionic derivatives were obtained. Theoretical and experimental studies show that the hydroxylammonium salt (7) is highly dense, and has excellent detonation performance with acceptable thermal stablity and sensitivities, which are superior to those of RDX. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Coherent spectroscopic methods for monitoring pathogens, genetically modified products and nanostructured materials in colloidal solution

    Science.gov (United States)

    Moguilnaya, T.; Suminov, Y.; Botikov, A.; Ignatov, S.; Kononenko, A.; Agibalov, A.

    2016-12-01

    We developed the new automatic method that combines the method of forced luminescence and stimulated Brillouin scattering. This method is used for monitoring pathogens, genetically modified products and nanostructured materials in colloidal solution. We carried out the statistical spectral analysis of pathogens, genetically modified soy and nano-particles of silver in water from different regions in order to determine the statistical errors of the method. We studied spectral characteristics of these objects in water to perform the initial identification with 95% probability. These results were used for creation of the model of the device for monitor of pathogenic organisms and working model of the device to determine the genetically modified soy in meat.

  4. Coherent spectroscopic methods for monitoring pathogens, genetically modified products and nanostructured materials in colloidal solution

    Directory of Open Access Journals (Sweden)

    Moguilnaya T.

    2017-01-01

    Full Text Available We developed the new automatic method that combines the method of forced luminescence and stimulated Brillouin scattering. This method is used for monitoring pathogens, genetically modified products and nanostructured materials in colloidal solution. We carried out the statistical spectral analysis of pathogens, genetically modified soy and nano-particles of silver in water from different regions in order to determine the statistical errors of the method. We studied spectral characteristics of these objects in water to perform the initial identification with 95% probability. These results were used for creation of the model of the device for monitor of pathogenic organisms and working model of the device to determine the genetically modified soy in meat.

  5. Attosecond nanotechnology: NEMS of energy storage and nanostructural transformations in materials

    Science.gov (United States)

    Beznosyuk, Sergey A.; Zhukovsky, Mark S.; Maslova, Olga A.

    2015-10-01

    The attosecond technology of the nanoelectromechanical system (NEMS) energy storage as active center fast transformation of nanostructures in materials is considered. The self-organizing relaxation of the NEMS active center containing nanocube of 256-atoms limited by planes (100) in the FCC lattice matrix of 4d-transition metals (Ru, Rh, Pd) is described by the quantum NEMS-kinetics (NK) method. Typical for these metals change of the NEMS active center physicochemical characteristics during the time of relaxation is presented. There are three types of intermediate quasistationary states of the NEMS active center. Their forms are plainly distinguishable. The full relaxed NEMS active centers (Ru256, Rh256, Pd256) accumulate next storage energies: ERu = 2.27 eV/at, ERh = 1.67 eV/at, EPd = 3.02 eV/at.

  6. Versatile, high sensitivity, and automatized angular dependent vectorial Kerr magnetometer for the analysis of nanostructured materials.

    Science.gov (United States)

    Teixeira, J M; Lusche, R; Ventura, J; Fermento, R; Carpinteiro, F; Araujo, J P; Sousa, J B; Cardoso, S; Freitas, P P

    2011-04-01

    Magneto-optical Kerr effect (MOKE) magnetometry is an indispensable, reliable, and one of the most widely used techniques for the characterization of nanostructured magnetic materials. Information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained from MOKE measurements. We present a description of our state-of-the-art vectorial MOKE magnetometer, being an extremely versatile, accurate, and sensitivity unit with a low cost and comparatively simple setup. The unit includes focusing lenses and an automatized stepper motor stage for angular dependent measurements. The performance of the magnetometer is demonstrated by hysteresis loops of Co thin films displaying uniaxial anisotropy induced on growth, MnIr/CoFe structures exhibiting the so called exchange bias effect, spin valves, and microfabricated flux guides produced by optical lithography.

  7. Nanostructured 2D cellular materials in silicon by sidewall transfer lithography NEMS

    Science.gov (United States)

    Syms, Richard R. A.; Liu, Dixi; Ahmad, Munir M.

    2017-07-01

    Sidewall transfer lithography (STL) is demonstrated as a method for parallel fabrication of 2D nanostructured cellular solids in single-crystal silicon. The linear mechanical properties of four lattices (perfect and defected diamond; singly and doubly periodic honeycomb) with low effective Young’s moduli and effective Poisson’s ratio ranging from positive to negative are modelled using analytic theory and the matrix stiffness method with an emphasis on boundary effects. The lattices are fabricated with a minimum feature size of 100 nm and an aspect ratio of 40:1 using single- and double-level STL and deep reactive ion etching of bonded silicon-on-insulator. Nanoelectromechanical systems (NEMS) containing cellular materials are used to demonstrate stretching, bending and brittle fracture. Predicted edge effects are observed, theoretical values of Poisson’s ratio are verified and failure patterns are described.

  8. Coherent spectroscopic methods for monitoring pathogens, genetically modified products and nanostructured materials in colloidal solution

    Science.gov (United States)

    Moguilnaya, T.; Suminov, Y.; Botikov, A.; Ignatov, S.; Kononenko, A.; Agibalov, A.

    2017-01-01

    We developed the new automatic method that combines the method of forced luminescence and stimulated Brillouin scattering. This method is used for monitoring pathogens, genetically modified products and nanostructured materials in colloidal solution. We carried out the statistical spectral analysis of pathogens, genetically modified soy and nano-particles of silver in water from different regions in order to determine the statistical errors of the method. We studied spectral characteristics of these objects in water to perform the initial identification with 95% probability. These results were used for creation of the model of the device for monitor of pathogenic organisms and working model of the device to determine the genetically modified soy in meat.

  9. Chemically modified and nanostructured porous silicon as a drug delivery material and device

    Science.gov (United States)

    Anglin, Emily Jessica

    This thesis describes the fabrication, chemical modification, drug release, and toxicity studies of nanostructured porous silicon for the purposes of developing a smart drug delivery device. The first chapter is an introductory chapter, presenting the chemical and physical properties of porous silicon, the concepts and issues of current drug delivery devices and materials, and how porous silicon can address the issues regarding localized and controlled drug therapies. The second chapter discusses chemical modifications of nanostructured porous Si for stabilizing the material in biologically relevant media while providing an extended release of a therapeutic in vitro. This chapter also demonstrates the utility of the porous silicon optical signatures for effectively monitoring drug release from the system and its applications for development of a self-reporting drug delivery device. In chapter three, the concept of providing a triggered release of a therapeutic from porous silicon microparticles through initiation by an external stimulus is demonstrated. The microparticles are chemically modified, and the release is enhanced by a short application of ultrasound to the particulate system. The effect of ultrasound on the drug release and particle size is discussed. Chapter four presents a new method for sustaining the release of a monoclonal antibody from the porous matrix of porous SiO2. The therapeutic is incorporated into the films through electrostatic adsorption and a slow release is observed in vitro. A new method of quantifying the extent of drug loading is monitored with interferometry. The last chapter of the thesis provides a basic in vivo toxicity study of various porous Si microparticles for intraocular applications. Three types of porous Si particles are fabricated and studied in a rabbit eye model. The toxicity studies were conducted by collaborators at the Shiley Eye Center, La Jolla, CA. This work, demonstrates the feasibility of developing a self

  10. Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co3O4 Nanostructures for Lithium Ion Battery Anode Materials

    DEFF Research Database (Denmark)

    Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong;

    2016-01-01

    We report a facile synthesis of a novel cobalt oxide (Co3O4) hierarchical nanostructure, in which crystalline core-amorphous shell Co3O4 nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co3O4 nanosheets. When tested as anode materials for lithium ion batteries...

  11. The influence of ZnO nanostructures on the structure, optical and photovoltaic properties of organic materials

    CSIR Research Space (South Africa)

    Malgas, GF

    2014-03-01

    Full Text Available Films Vol. 555 The influence of ZnO nanostructures on the structure, optical and photovoltaic properties of organic materials Gerald F. Malgas a,b,⁎, David E. Motaung a,⁎⁎, Gugu H. Mhlongo a, Steven S. Nkosi c, Bonex W. Mwakikunga a, Malcolm...

  12. Effect of Nanostructure Changes on Stress Corrosion Cracking of Proton Irradiated Nuclear Energy Structural Materials

    Directory of Open Access Journals (Sweden)

    M.N. Lunika

    2011-01-01

    Full Text Available Austenitic stainless alloys are used extensively as structural materials in the internal components of light water reactor (LWR pressure vessels because of their relatively high strength, ductility, and fracture toughness. Irradiation-assisted stress corrosion cracking (IASCC is main degradation process that affects LWR internal components exposed to radiation. The existing data on proton irradiated austenitic alloys were reviewed to evaluate the effects of key parameters such as material composition, irradiation dose on IASCC susceptibility of these materials in LWR environments. The significance of deformation nanostructure and stacking fault energy (SFE changes in the material on IASCC susceptibility is also discussed. Results show that the IASCC susceptibility of the alloys increases with increasing irradiation dose and decreasing stacking fault energy. IASCC tends to initiate at locations where slip dislocation channels intersect grain boundaries. Localized deformation in the form of grain boundary sliding due to the interaction of slip channels and grain boundaries is likely the primary cause of the observed cracking initiation. It may play a key role in the underlying mechanism of IASCC in light water reactor core components.

  13. Prediction of detonation and JWL eos parameters of energetic materials using EXPLO5 computer code

    CSIR Research Space (South Africa)

    Peter, Xolani

    2016-09-01

    Full Text Available (Cowperthwaite and Zwisler, 1976), CHEETAH (Fried, 1996), EXPLO5(Sućeska , 2001), BARUT-X (Cengiz et al., 2007). These computer codes describe the detonation on the basis of the solution of Euler’s hydrodynamic equation based on the description of an equation... of detonation products equation of state from cylinder test: Analytical model and numerical analysis. Thermal Science, 19(1), pp. 35-48. Fried, L.E., 1996. CHEETAH 1.39 user’s manual. Lawrence Livermore National Laboratory. Göbel, M., 2009. Energetic...

  14. High capacity and high rate capability of nanostructured CuFeO 2 anode materials for lithium-ion batteries

    Science.gov (United States)

    Lu, Lin; Wang, Jia-Zhao; Zhu, Xue-Bin; Gao, Xuan-Wen; Liu, Hua-Kun

    Non-toxic, cheap, nanostructured ternary transition metal oxide CuFeO 2 was synthesised using a simple sol-gel method at different temperatures. The effects of the processing temperature on the particle size and electrochemical performance of the nanostructured CuFeO 2 were investigated. The electrochemical results show that the sample synthesised at 650 °C shows the best cycling performance, retaining a specific capacity of 475 mAh g -1 beyond 100 cycles, with a capacity fading of less than 0.33% per cycle. The electrode also exhibits good rate capability in the range of 0.5 C-4 C. At the high rate of 4 C, the reversible capacity of CuFeO 2 is around 170 mAh g -1. It is believed that the ternary transition metal oxide CuFeO 2 is quite acceptable compared with other high performance nanostructured anode materials.

  15. Non-equilibrium grain boundaries in titanium nanostructured by severe plastic deformation: Computational study of sources of material strengthening

    DEFF Research Database (Denmark)

    Liu, Hongsheng; Mishnaevsky, Leon; Pantleon, Wolfgang

    2014-01-01

    A computational model of ultrafine grained (UFG) or nanostructured titanium (Ti), based on a finite element (FE) unit cell model of the material and a dislocation density based model of plastic deformation has been developed. FE simulations of tensile deformation of UFG Ti with different fractions...... and properties of the grain boundary (GB) phase have been carried out. The effect of different degrees of deviation from the equilibrium state of the grain boundaries (GBs) on the mechanical behaviour of nanostructured Ti have been investigated using the combined composite/dislocation dynamics based model....... In particular, the effects of different diffusion coefficients in the GB phase, of a high initial dislocation density in the grain boundaries, as well as of atomic scale precipitates are investigated for affecting the deformation behaviour of UFG or nanostructured Ti. © 2013 Elsevier B.V. All rights reserved....

  16. Elucidating the decomposition mechanism of energetic materials with geminal dinitro groups using 2-bromo-2-nitropropane photodissociation.

    Science.gov (United States)

    Booth, Ryan S; Lam, Chow-Shing; Brynteson, Matthew D; Wang, Lei; Butler, Laurie J

    2013-10-03

    These experiments photolytically generate two key intermediates in the decomposition mechanisms of energetic materials with nitro substituents, 2-nitropropene, and 2-nitro-2-propyl radicals. These intermediates are produced at high internal energies and access a number of competing unimolecular dissociation channels investigated herein. We use a combination of crossed laser-molecular beam scattering and velocity map imaging to study the photodissociation of 2-bromo-2-nitropropane at 193 nm and the subsequent unimolecular dissociation of the intermediates above. Our results demonstrate that 2-bromo-2-nitropropane has four primary photodissociation pathways: C-Br bond fission yielding the 2-nitro-2-propyl radical, HBr elimination yielding 2-nitropropene, C-N bond fission yielding the 2-bromo-2-propyl radical, and HONO elimination yielding 2-bromopropene. The photofragments are formed with significant internal energy and undergo many secondary dissociation events, including the exothermic dissociation of 2-nitro-2-propyl radicals to NO + acetone. Calculations at the G4//B3LYP/6-311++g(3df,2p) level show that the presence of a radical at a nitroalkyl center changes the mechanism for and substantially lowers the barrier to NO loss. This mechanism involves an intermediate with a three-center ring rather than the intermediate formed during the traditional nitro-nitrite isomerization. The observed dissociation pathways of the 2-nitro-2-propyl radical and 2-nitropropene help elucidate the decomposition mechanism of larger energetic materials with geminal dinitro groups.

  17. Detection of anionic energetic material residues in enhanced fingermarks on porous and non-porous surfaces using ion chromatography.

    Science.gov (United States)

    Love, Catherine; Gilchrist, Elizabeth; Smith, Norman; Barron, Leon

    2013-09-10

    The ability to link criminal activity and identity using validated analytical approaches can be of great value to forensic scientists. Herein, the factors affecting the recovery and detection of inorganic and organic energetic material residues within chemically or physically enhanced fingermarks on paper and glass substrates are presented using micro-bore anion exchange chromatography with suppressed conductivity detection. Fingermarks on both surfaces were enhanced using aluminium powder or ninhydrin after spiking with model test mixtures or through contact with black-powder substitutes. A quantitative study of the effects of environmental/method interferences, the sweat matrix, the surface and the enhancement technique on the relative anion recovery of forensically relevant species is presented. It is shown that the analytical method could detect target analytes at the nanogram level even within excesses of enhancement reagents and their reaction products when using solid phase extraction and/or microfiltration. To our knowledge, this work demonstrates for the first time that ion chromatography can detect anions in energetic materials within fingermarks on two very different surfaces, after operational enhancement techniques commonly used by forensic scientists and police have been applied.

  18. Energetic Systems

    Data.gov (United States)

    Federal Laboratory Consortium — The Energetic Systems Division provides full-spectrum energetic engineering services (project management, design, analysis, production support, in-service support,...

  19. Recent progress on nanostructured 4 V cathode materials for Li-ion batteries for mobile electronics

    Directory of Open Access Journals (Sweden)

    Xiaodong Xu

    2013-12-01

    Full Text Available Mobile electronics have developed so rapidly that battery technology has hardly been able to keep pace. The increasing desire for lighter and thinner Li-ion batteries with higher capacities is a continuing and constant goal for in research. Achieving higher energy densities, which is mainly dependent on cathode materials, has become a critical issue in the development of new Li-ion batteries. In this review, we will outline the progress on nanostructured 4 V cathode materials of Li-ion batteries for mobile electronics, covering LiCoO2, LiNixCoyMn1−x−yO2, LiMn2O4, LiNi0.5Mn1.5O4 and Li-rich layered oxide materials. We aim to provide some scientific insights into the development of superior cathode materials by discussing the advantages of nanostructure, surface-coating, and other key properties.

  20. Quantum-chemical Investigation of Substituted s-Tetrazine Derivatives as Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ghule, Vikas D.; Tewari, Surya P. [University of Hyderabad, Hyderabad (India); Sarangapani, Radhakrishnan; Jadhav, Pandurang M. [High Energy Materials Research Laboratory, Pune (India)

    2012-02-15

    s-Tetrazine is the essential candidate of many energetic compounds due to its high nitrogen content, enthalpy of formation and thermal stability. The present study explores the design of s-tetrazine derivatives in which different -NO{sub 2}, -NH{sub 2} and -N{sub 3} substituted azoles are attached to the tetrazine ring via C-N linkage. The density functional theory (DFT) is used to predict the geometries, heats of formation (HOFs) and other energetic properties. The predicted results show that azide group plays a very important role in increasing HOF values of the s-tetrazine derivatives. The densities for designed molecules were predicted by using the crystal packing calculations. The introduction of -NO{sub 2} group improves the density as compared to -N{sub 3}, and -NH{sub 2} groups and hence the detonation performance. Bond dissociation energy analysis and insensitivity correlations revealed that amino derivatives are better candidates considering insensitivity and stability.

  1. Computational Study on Substituted s-Triazine Derivatives as Energetic Materials

    Directory of Open Access Journals (Sweden)

    Vikas D. Ghule

    2012-01-01

    Full Text Available s-Triazine is the essential candidate of many energetic compounds due to its high nitrogen content, enthalpy of formation and thermal stability. The present study explores s-triazine derivatives in which different -NO2, -NH2 and -N3 substituted azoles are attached to the triazine ring via C-N linkage. The density functional theory is used to predict geometries, heats of formation and other energetic properties. Among the designed compounds, -N3 derivatives show very high heats of formation. The densities for designed compounds were predicted by using the crystal packing calculations. Introduction of -NO2 group improves density as compared to -NH2 and -N3, their order of increasing density can be given as NO2>N3>NH2. Analysis of the bond dissociation energies for C-NO2, C-NH2 and C-N3 bonds indicates that substitutions of the -N3 and -NH2 group are favorable for enhancing the thermal stability of s-triazine derivatives. The nitro and azido derivatives of triazine are found to be promising candidates for the synthetic studies.

  2. 1-(3,5-Dinitro-1H-pyrazol-4-yl)-3-nitro-1H-1,2,4-triazol-5-amine (HCPT) and its energetic salts: highly thermally stable energetic materials with high-performance.

    Science.gov (United States)

    Li, Chuan; Zhang, Man; Chen, Qishan; Li, Yingying; Gao, Huiqi; Fu, Wei; Zhou, Zhiming

    2016-11-28

    A novel energetic heat-resistant explosive, 1-(3,5-dinitro-1H-pyrazol-4-yl)-3-nitro-1H-1,2,4-triazol-5-amine (HCPT), has been synthesized along with its salts. An intensive characterization of the compounds is given, including (1)H and (13)C NMR spectroscopy, IR spectroscopy, and elemental analysis. The crystal structures of neutral HCPT (3), its triaminoguanidinium salt (10), 3,4,5-triamino-1,2,4-triazolium salt (12), and copper(ii) complex (16) were determined by single-crystal X-ray diffraction. The physicochemical properties of the compounds, such as density, thermal stability, and sensitivity towards impact and friction were evaluated; all energetic compounds exhibited excellent thermal stabilities with decomposition temperatures ranging from 215 °C to 340 °C, and high positive heats of formation between 622.8 kJ mol(-1) and 1211.7 kJ mol(-1). The detonation pressures and velocities for the energetic compounds were calculated using EXPLO5 (V6.01) based on experimental densities and calculated heats of formation, and the corresponding values were in the ranges of 26.5 GPa to 37.8 GPa and 8236 m s(-1) to 9167 m s(-1). Based on thermal stability values and energetic parameters, compounds 3 and 7 were superior to those of all of the commonly used heat-resistant explosives, which may find potential application as heat-resistant energetic materials.

  3. Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Tercjak, A; Garcia, I; Mondragon, I [Materials-Technologies Group, Departamento IngenierIa Quimica y M Ambiente, Escuela Politecnica, Universidad PaIs Vasco/Euskal Herriko Unibertsitatea, Plaza Europa 1, E-20018 Donostia-San Sebastian (Spain)], E-mail: scptesza@sc.ehu.es, E-mail: inaki.mondragon@ehu.es

    2008-07-09

    Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.

  4. Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

    Science.gov (United States)

    Tercjak, A.; Garcia, I.; Mondragon, I.

    2008-07-01

    Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.

  5. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    Science.gov (United States)

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-03-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10-20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed.

  6. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    Science.gov (United States)

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-01-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10–20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed. PMID:28291246

  7. Nanostructured materials and their role as heterogeneous catalysts in the conversion of biomass to biofuels

    Science.gov (United States)

    Cadigan, Chris

    Prior to the discovery of inexpensive and readily available fossil fuels, the world relied heavily on biomass to provide its energy needs. Due to a worldwide growth in demand for fossil fuels coupled with the shrinkage of petroleum resources, and mounting economic, political, and environmental concerns, it has become more pressing to develop sustainable fuels and chemicals from biomass. The present dissertation studies multiple nanostructured catalysts investigated in various processes related to gasification of biomass into synthesis gas, and further upgrading to biofuels and value added chemicals. These reactions include: syngas conditioning, alcohol synthesis from carbon monoxide hydrogenation, and steam reforming ethanol to form higher hydrocarbons. Nanomaterials were synthesized, characterized, studied in given reactions, and then further characterized post-reaction. Overall goals were aimed at determining catalytic activities towards desired products and determining which material properties were most desirable based on experimental results. Strategies to improve material design for second-generation materials are suggested based on promising reaction results coupled with pre and post reaction characterization analysis.

  8. Nanostructured Inorganic Materials at Work in Electrochemical Sensing and Biofuel Cells

    Directory of Open Access Journals (Sweden)

    Yaovi Holade

    2017-01-01

    Full Text Available The future of analytical devices, namely (biosensors, which are currently impacting our everyday life, relies on several metrics such as low cost, high sensitivity, good selectivity, rapid response, real-time monitoring, high-throughput, easy-to-make and easy-to-handle properties. Fortunately, they can be readily fulfilled by electrochemical methods. For decades, electrochemical sensors and biofuel cells operating in physiological conditions have concerned biomolecular science where enzymes act as biocatalysts. However, immobilizing them on a conducting substrate is tedious and the resulting bioelectrodes suffer from stability. In this contribution, we provide a comprehensive, authoritative, critical, and readable review of general interest that surveys interdisciplinary research involving materials science and (bioelectrocatalysis. Specifically, it recounts recent developments focused on the introduction of nanostructured metallic and carbon-based materials as robust “abiotic catalysts” or scaffolds in bioelectrochemistry to boost and increase the current and readout signals as well as the lifetime. Compared to biocatalysts, abiotic catalysts are in a better position to efficiently cope with fluctuations of temperature and pH since they possess high intrinsic thermal stability, exceptional chemical resistance and long-term stability, already highlighted in classical electrocatalysis. We also diagnosed their intrinsic bottlenecks and highlighted opportunities of unifying the materials science and bioelectrochemistry fields to design hybrid platforms with improved performance.

  9. Synthesis of 5-aminotetrazole-1N-oxide and its azo derivative: a key step in the development of new energetic materials.

    Science.gov (United States)

    Fischer, Dennis; Klapötke, Thomas M; Piercey, Davin G; Stierstorfer, Jörg

    2013-04-01

    1-Hydroxy-5-aminotetrazole (1), which is a long-desired starting material for the synthesis of hundreds of new energetic materials, was synthesized for the first time by the reaction of aqueous hydroxylamine with cyanogen azide. The use of this unique precursor was demonstrated by the preparation of several energetic compounds with equal or higher performance than that of commonly used explosives, such as hexogen (RDX). The prepared compounds, including energetic salts of 1-hydroxy-5-aminotetrazole (hydroxylammonium (2, two polymorphs) and ammonium (3)), azo-coupled derivatives (potassium (5), hydroxylammonium (6), ammonium (7), and hydrazinium 5,5'-azo-bis(1-N-oxidotetrazolate (8, two polymorphs)), as well as neutral compounds 5,5'-azo-bis(1-oxidotetrazole) (4) and 5,5'-bis(1-oxidotetrazole)hydrazine (9), were intensively characterized by low-temperature X-ray diffraction, IR, Raman, and multinuclear NMR spectroscopy, elemental analysis, and DSC. The calculated energetic performance, by using the EXPLO5 code, based on the calculated (CBS-4M) heats of formation and X-ray densities confirm the high energetic performance of tetrazole-N-oxides as energetic materials. Last but not least, their sensitivity towards impact, friction, and electrostatic discharge were explored. 5,5'-Azo-bis(1-N-oxidotetrazole) deflagrates close to the DDT (deflagration-to-detonation transition) faster than all compounds that have been investigated in our research group to date.

  10. Conceptual study on a new generation of the high-innovative advanced porous and composite nanostructural functional materials with nanofibers

    OpenAIRE

    L.A. Dobrzański; M. Pawlyta; A. Hudecki

    2011-01-01

    Purpose: The purpose of the paper is to analyse theoretically the possibilities of the development of a new generation of the high-innovative advanced porous and composite nanostructural functional materials with nanofibers and to study into the material science grounds of synthesis and/or production and formulation of such materials’ structure and properties and to characterise and model their structure and properties depending on the compositional, phase and chemical composition and the app...

  11. Nanostructured complex cobalt oxides as potential materials for solar thermoelectric power generators

    Energy Technology Data Exchange (ETDEWEB)

    Robert, R.; Romer, S.; Weidenkaff, A. [Laboratory of Solid State Chemistry and Analyses, Empa Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Dubendorf (Switzerland); Reller, A. [Solid State Chemistry, University of Augsburg, Universitaetsstrasse 1, D-86150 Augsburg (Germany)

    2005-05-01

    Thermoelectrically active and stable perovskite-type materials e.g. La{sub 1-x}Ca{sub x}CoO{sub 3} (0nanostructured ''misfit cobaltite Ca{sub 3}Co{sub 4}O{sub 9}'' shows a Seebeck coefficient of S{sub 300K} {proportional_to} + 123 {mu}VK{sup -1}, and a resistivity of {rho} {proportional_to} 1.9 m{omega} cm at room temperature, which is comparable to the reported value for single crystals. Ca- and Ti-substituted LaCoO{sub 3} reveal thermopower values in the range from S{sub 300K} {proportional_to} + 70 to + 180 {mu}VK{sup -1}. The electrical conductivity of the nanostructured compounds is high in spite of the fact that the grain boundary influence is increasing. The Seebeck coefficient values of the products are positive in the whole temperature range indicating p-type conduction. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  12. Neutron scattering—The key characterization tool for nanostructured magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Fitzsimmons, M.R., E-mail: fitz@lanl.gov [Los Alamos National Laboratory (United States); Schuller, Ivan K. [University of California, San Diego (United States)

    2014-01-15

    The novel properties of materials produced using nanoscale manufacturing processes often arise from interactions across interfaces between dissimilar materials. Thus, to characterize the structure and magnetism of nanoscale materials demands tools with interface specificity. Neutron scattering has long been known to provide unique and quantitative information about nuclear and magnetic structures of bulk materials. Moreover, the specialty techniques of polarized neutron reflectometry and small angle neutron scattering (SANS) with polarized neutron beams and polarization analysis, are ideally and often uniquely suited to studies of nanostructured magnetic materials. Since neutron scattering is a weakly interacting probe, it gives quantifiable and easily-interpreted information on properties of statistically representative quantities of bulk, thin film and interfacial materials. In addition, neutron scattering can provide information to complement that obtained with bulk probes (magnetization, Kerr effect) or surface measurements obtained with scanning probe microscopy or resonant soft x-ray scattering. The straightforward interpretation and the simultaneous availability of structural information, make neutron scattering the technique of choice for the structural and physical characterization of many novel materials, especially those with buried interfaces, ones allowing for isotopic substitutions to decorate buried interfaces, or cases where the magnetic response to an external stimulus can be measured. We describe recent applications of neutron scattering to important thin film materials systems and future opportunities. Unquestionably, neutron scattering has played a decisive role in the development and study of new emergent phenomena. We argue with the advent of new techniques in neutron scattering and sample environment, neutron scattering's role in such studies will become even more dominant. In particular, neutron scattering will clarify and distinguish

  13. Influence of pressure-driven gas permeation on the quasi-steady burning of porous energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Margolis, S.B.

    1997-09-01

    A theoretical two-phase-flow analysis is developed to describe the quasi-steady propagation, across a pressure jump, of a multi-phase deflagration in confined porous energetic materials. The difference, or overpressure, between the upstream (unburned) and downstream (burned) gas pressure leads to a more complex structure than that which is obtained for an unconfined deflagration in which the pressure across the multi-phase flame region is approximately constant. In particular, the structure of such a wave is shown by asymptotic methods to consist of a thin boundary layer characterized by gas permeation into the unburned solid, followed by a liquid/gas flame region, common to both types of problems, in which the melted material is preheated further and ultimately converted to gaseous products. The effect of gas flow relative to the condensed material is shown to be significant, both in the porous unburned solid as well as in the exothermic liquid/gas melt layer, and is, in turn, strongly affected by the overpressure. Indeed, all quantities of interest, including the burned temperature, gas velocity and the propagation speed, depend on this pressure difference, leading to a significant enhancement of the burning rate with increasing overpressure. In the limit that the overpressure becomes small, the pressure gradient is insufficient to drive gas produced in the reaction zone in the upstream direction, and all gas flow relative to the condensed material is directed in the downstream direction, as in the case of an unconfined deflagration. The present analysis is particularly applicable to those types of porous energetic solids, such as degraded nitramine propellants, that can experience significant gas flow in the solid preheat region and which are characterized by the presence of exothermic reactions in a bubbling melt layer at their surfaces. 7 refs., 6 figs.

  14. Effects of two-phase flow on the deflagration of porous energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Margolis, S.B. [Sandia National Labs., Livermore, CA (United States); Williams, F.A. [Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Applied Mechanics and Engineering Sciences

    1994-07-01

    Theoretical analyses are developed for the multi-phase deflagration of porous energetic solids, such as degraded nitramine propellants, that experience significant gas flow in the solid preheat region and are characterized by the presence of exothermic reactions in a bubbling melt layer at their surfaces. Relative motion between the gas and condensed phases is taken into account in both regions, and expressions for the mass burning rate and other quantities of interest, such as temperature and volume-fraction profiles, are derived by activation-energy asymptotics. The model extends recent work by allowing for gas flow in the unburned solid, and by incorporating pressure effects through the gas-phase equation of state. As a consequence, it is demonstrated how most aspects of the deflagration wave, including its structure, propagation speed and final temperature, depend on the local pressure in the two-phase regions.

  15. Diffuse Interface Methods for Multiple Phase Materials: An Energetic Variational Approach

    CERN Document Server

    Brannick, J; Qian, T; Sun, H

    2014-01-01

    In this paper, we introduce a diffuse interface model for describing the dynamics of mixtures involving multiple (two or more) phases. The coupled hydrodynamical system is derived through an energetic variational approach. The total energy of the system includes the kinetic energy and the mixing (interfacial) energies. The least action principle (or the principle of virtual work) is applied to derive the conservative part of the dynamics, with a focus on the reversible part of the stress tensor arising from the mixing energies. The dissipative part of the dynamics is then introduced through a dissipation function in the energy law, in line with the Onsager principle of least energy dissipation. The final system, formed by a set of coupled time-dependent partial differential equations, reflects a balance among various conservative and dissipative forces and governs the evolution of velocity and phase fields. To demonstrate the applicability of the proposed model, a few two-dimensional simulations have been car...

  16. Transport of energetic electrons in solids computer simulation with applications to materials analysis and characterization

    CERN Document Server

    Dapor, Maurizio

    2017-01-01

    This new edition describes all the mechanisms of elastic and inelastic scattering of electrons with the atoms of the target as simple as possible. The use of techniques of quantum mechanics is described in detail for the investigation of interaction processes of electrons with matter. It presents the strategies of the Monte Carlo method, as well as numerous comparisons among the results of the simulations and the experimental data available in the literature. New in this edition is the description of the Mermin theory, a comparison between Mermin theory and Drude theory, a discussion about the dispersion laws, and details about the calculation of the phase shifts that are used in the relativistic partial wave expansion method. The role of secondary electrons in proton cancer therapy is discussed in the chapter devoted to applications. In this context, Monte Carlo results about the radial distribution of the energy deposited in PMMA by secondary electrons generated by energetic proton beams are presented.

  17. Optoacoustic Microscopy for Investigation of Material Nanostructures-Embracing the Ultrasmall, Ultrafast, and the Invisible

    Energy Technology Data Exchange (ETDEWEB)

    Nurmikko, Arto; Humphrey, Maris

    2014-07-10

    The goal of this grant was the development of a new type of scanning acoustic microscope for nanometer resolution ultrasound imaging, based on ultrafast optoacoustics (>GHz). In the microscope, subpicosecond laser pulses was used to generate and detect very high frequency ultrasound with nanometer wavelengths. We report here on the outcome of the 3-year DOE/BES grant which involved the design, multifaceted construction, and proof-of-concept demonstration of an instrument that can be used for quantitative imaging of nanoscale material features – including features that may be buried so as to be inaccessible to conventional lightwave or electron microscopies. The research program has produced a prototype scanning optoacoustic microscope which, in combination with advanced computational modeling, is a system-level new technology (two patents issues) which offer novel means for precision metrology of material nanostructures, particularly those that are of contemporary interest to the frontline micro- and optoelectronics device industry. For accomplishing the ambitious technical goals, the research roadmap was designed and implemented in two phases. In Phase I, we constructed a “non-focusing” optoacoustic microscope instrument (“POAM”), with nanometer vertical (z-) resolution, while limited to approximately 10 micrometer scale lateral recolution. The Phase I version of the instrument which was guided by extensive acoustic and optical numerical modeling of the basic underlying acoustic and optical physics, featured nanometer scale close loop positioning between the optoacoustic transducer element and a nanostructured material sample under investigation. In phase II, we implemented and demonstrated a scanning version of the instrument (“SOAM”) where incident acoustic energy is focused, and scanned on lateral (x-y) spatial scale in the 100 nm range as per the goals of the project. In so doing we developed advanced numerical simulations to provide

  18. Modeling and characterization of the elastic behavior of interfaces in nanostructured materials: From an atomistic description to a continuum approach

    Science.gov (United States)

    Dingreville, Remi

    Steady technological progresses in all fields of nanoscale technology and probe technology have enabled the synthesis, the assembly, the development, the characterization and the improvement of nanostructured materials. The lack of understanding of their macroscopic behavior is a major roadblock for inserting these materials into engineering applications. Partially due to these rapid advances in nano-scale and nano-structured materials, there has been a resurgence of interest in surface elastic properties such as surface energy, surface stresses, and surface elastic stiffness. Because of the large surface-to-volume ratio in nano-materials, surface elastic properties become more prominent. They have strong influence on the overall thermo-mechanical behavior of the nano-materials. In this dissertation, an innovative approach combining continuum mechanics and atomistic simulations is exposed to develop a nanomechanics theory for modeling and predicting the macroscopic behavior of nanomaterials. This nanomechanics theory exhibits the simplicity of the continuum formulation while taking into account the discrete atomic structure and interaction near surfaces/interfaces. There are four primary objectives to this dissertation. First, theory of interfaces is revisited to better understand its behavior and effects on the overall behavior of nanostructures. Second, atomistic tools are provided in order to efficiently determine the properties of free surfaces and interfaces. Interface properties are reported in this work, with comparison to both theoretical and experimental characterizations of interfaces. Specifically, we report surface elastic properties of groups 10--11 transition metals as well as properties for low-CSL grain boundaries in copper. Third, we propose a continuum framework that casts the atomic level information into continuum quantities that can be used to analyze, model and simulate macroscopic behavior of nanostructured materials. In particular, we study

  19. Precursor Derived Nanostructured Si-C-X Materials for Nuclear Applications. Final Report, October 2010 - September 2014

    Energy Technology Data Exchange (ETDEWEB)

    Bordia, Rajendra [Univ. of Washington, Seattle, WA (United States); Tomar, Vikas [Purdue Univ., West Lafayette, IN (United States); Henager, Chuck [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-08

    Polymer derived ceramic route is an attractive approach to make structural materials with unique nanostructures that have very desirable high temperature properties. Processing techniques to make a variety of needed shapes and forms (e.g. coatings, matrices for fiber reinforced composites, porous ceramics) have been developed. With appropriate high temperature processing, the precursors can be converted to nano-crystalline materials. In this collaborative project, we investigated the processing, stability and properties of nanostructured Si-C materials, derived from polymeric precursors, and their performance under conditions appropriate for nuclear energy applications. All the milestones of the project were accomplished. Some of the results are being currently analyzed and additional papers being prepared in which support from NEUP will be acknowledged. So far, eight peer-reviewed papers have been published and one invention disclosure made. In this report, we summarize the major findings of this project.

  20. Alternative materials and processing techniques for optimized nanostructures in dye-sensitized solar cells.

    Science.gov (United States)

    Hart, Judy N; Cheng, Yi-Bing; Simon, George P; Spiccia, Leone

    2008-05-01

    Dye-sensitized solar cells (DSSCs) represent an exciting application of nanotechnology and offer an appealing alternative to conventional solar cells based on photovoltaic devices, with significantly reduced production and material costs. However, further improvements are required to enhance the commercial viability of these solar cells. These improvements may be achieved through the careful manipulation of the structure at the nanoscale and the application of novel processing techniques, which may help to increase the efficiency of these solar cells, improve the ease of manufacture and allow the production of flexible, solid-state solar cells. For example, the use of a nanometre-thick coating of an insulating oxide over the semiconducting film in these solar cells may reduce recombination losses. Also, selective heating techniques such as microwave heating may assist in the production of efficient solar cells on polymer, rather than glass, substrates, by allowing a rapid heat treatment to be applied to the titanium dioxide film at a higher temperature than would be possible with conventional heating. Some novel approaches to the production of semiconducting thin films for dye-sensitized solar cells, as well as the use of alternative materials and nanostructures, are reviewed.