Cutting and machining energetic materials with a femtosecond laser

Energy Technology Data Exchange (ETDEWEB)

Roeske, Frank; Benterou, Jerry; Lee, Ronald; Roos, Edward [Energetic Materials Center, Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94550 (United States)

2003-04-01

A femtosecond (fs) laser has been used as a tool for solving many problems involving access, machining, disassembly, inspection and avoidance of undesirable hazardous waste streams in systems containing energetic materials. Because of the unique properties of the interaction of ultrashort laser pulses with matter, the femtosecond laser can be used to safely cut these energetic materials in a precise manner without creating an unacceptable waste stream. Many types of secondary high explosives (HE) and propellants have been cut with the laser for a variety of applications ranging from disassembly of aging conventional weapons (demilitarization), inspection of energetic components of aging systems to creating unique shapes of HE for purposes of initiation and detonation physics studies. Hundreds of samples of energetic materials have been cut with the fs laser without ignition and, in most cases, without changing the surface morphology of the cut surfaces. The laser has also been useful in cutting nonenergetic components in close proximity to energetic materials. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Erosion tests of materials by energetic particle beams

Energy Technology Data Exchange (ETDEWEB)

Schechter, D.E.; Tsai, C.C.; Sluss, F.; Becraft, W.R.; Hoffman, D.J.

1985-01-01

The internal components of magnetic fusion devices must withstand erosion from and high heat flux of energetic plasma particles. The selection of materials for the construction of these components is important to minimize contamination of the plasma. In order to study various materials' comparative resistance to erosion by energetic particles and their ability to withstand high heat flux, water-cooled copper swirl tubes coated or armored with various materials were subjected to bombardment by hydrogen and helium particle beams. Materials tested were graphite, titanium carbide (TiC), chromium, nickel, copper, silver, gold, and aluminum. Details of the experimental arrangement and methods of application or attachment of the materials to the copper swirl tubes are presented. Results including survivability and mass losses are discussed.

Environmentally benign destruction of waste energetic materials (EMs)

International Nuclear Information System (INIS)

Schneider, R. L.; Donahue, B. A.

1998-01-01

Studies by the U. S. Army Corps of Engineers during 1991-1997 involving various methods for the destruction of waste generated by pyrotechnic, explosive and propellant materials are described. The methods assessed and evaluated include controlled incineration (CI), wet air oxidation (WAO), and hydrothermal oxidation (HTO), using a U.S. Army triple-base propellant as the initial common standard for all destructor comparative testing. All three of these methods has special feed line restrictions requiring mechanical diminution and comminution of the energetic material which, for safety reasons, cannot be used with contaminated heterogeneous production wastes. Supercritical fluid extraction with carbon dioxide, alkaline hydrolysis, electrolysis and fluid cutting with very high pressure water jets and liquid nitrogen are alternate technologies that were evaluated as pre-treatment for production wastes. Wet air oxidation and electrochemical reduction studies were conducted using the U.S. Navy double propellant NOSIH-AA2, which contains a lead-based ballistic modifier. Wet air oxidation and hydrothermal oxidation studies were done using potassium dinitramide phase-stabilized nitrate as an oxidizer. All of these technologies are considered to be suitable for the environmentally benign destruction of pyrotechnic materials, including fireworks. 17 refs., 8 tabs., 4 figs

Electrostatic interactions for directed assembly of high performance nanostructured energetic materials of Al/Fe2O3/multi-walled carbon nanotube (MWCNT)

International Nuclear Information System (INIS)

Zhang, Tianfu; Ma, Zhuang; Li, Guoping; Wang, Zhen; Zhao, Benbo; Luo, Yunjun

2016-01-01

Electrostatic self-assembly in organic solvent without intensively oxidative or corrosive environments, was adopted to prepare Al/Fe 2 O 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 2 O 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 2 O 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 2 O 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 2 O 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 2 O 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 strategy can be applied into other nanostructured

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.

Source Characterization Model (SCM): A Predictive Capability for the Source Terms of Residual Energetic Materials from Burning and/or Detonation Activities

National Research Council Canada - National Science Library

Brown, Robert C; Kolb, Charles E; Conant, John A; Zhang, John; Dussault, David M; Rush, Tamera L; Conway, Brooke E; Morris, James W; Touma, Joe

2004-01-01

.... Detonation of energetic materials produces a wide range of air and surface pollutants, including carbon monoxide, nitrogen oxides, volatile organic compounds, acid gases, and particulate matter...

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

International Nuclear Information System (INIS)

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

Nitrogen-doped carbon based on peptides of hair as electrode materials for surpercapacitors

International Nuclear Information System (INIS)

Guo, Zihan; Zhou, Qingwen; Wu, Zhaojun; Zhang, Zhiguo; Zhang, Wen; Zhang, Yao; Li, Lijun; Cao, Zhenzhu; Wang, Hong; Gao, Yanfang

2013-01-01

Highlights: • Hair was directly carbonized by environmental and energy-saving methods. • Hair was utilized to prepare nitrogen-doped carbon materials for supercapacitor. • A new approache for preparing nitrogen-rich active carbon from biomass waste of hair-like precursor. • Hair-based carbon having a non-crystalline layered structure and excellent capacitive performance. -- Abstract: Hair, a high-nitrogen energetic material, is utilized as a precursor for nitrogen-doped porous carbon. The preparation procedures for obtaining carbon from hair are very simple, namely, reductant or deionized water activation process followed by hair carbonization under argon atmosphere at 800 °C for 2 h. The samples are characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption, and X-ray photoelectron microscopy. The carbon samples are tested as electrode materials in supercapacitors in a three-electrode system. The carbon (soaked in deionized water at 80 °C) presents relatively low specific surface areas (441.34 m 2 g −1 ) and shows higher capacitance (154.5 F g −1 ) compared with nitrogen-free commercial activated carbons (134.5 F g −1 ) at 5 A g −1 . The capacitance remains at 130.5 F g −1 even when the current load is increased to 15 A g −1 . The capacitance loss is only 5% in 6 M KOH after 10,000 charge and discharge cycles at 5 A g −1 . It is the unique microstructure after activation processing and electroactive nitrogen functionalities that enable the carbon obtained through a simple, ecological, and economical process to be utilized as a potential electrode material for electrical double-layer capacitors

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

Energetic materials: crystallization, characterization and insensitive plastic bonded explosives

Energy Technology Data Exchange (ETDEWEB)

Heijden, Antoine E.D.M. van der; Creyghton, Yves L.M.; Marino, Emanuela; Bouma, Richard H.B.; Scholtes, Gert J.H.G.; Duvalois, Willem [TNO Defence, Security and Safety, P. O. Box 45, 2280 AA Rijswijk (Netherlands); Roelands, Marc C.P.M. [TNO Science and Industry, P. O. Box 342, 7300 AH Apeldoorn (Netherlands)

2008-02-15

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 containing these energetic materials becomes. The application of submicron or nanometric energetic materials is generally considered to further decrease the sensitiveness of explosives. In order to assess the product quality of energetic materials, a range of analytical techniques is available. Recent attempts within the Reduced-sensitivity RDX Round Robin (R4) have provided the EM community a better insight into these analytical techniques and in some cases a correlation between product quality and shock initiation of plastic bonded explosives containing (RS-)RDX was identified, which would provide a possibility to discriminate between conventional and reduced sensitivity grades. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Energetic Metastable Oxygen and Nitrogen Atoms in the Terrestrial Atmosphere

Science.gov (United States)

Kharchenko, Vasili; Dalgarno, A.

2005-01-01

This report summarizes our research performed under NASA Grant NAG5-11857. The three-year grant have been supported by the Geospace Sciences SR&T program. We have investigated the energetic metastable oxygen and nitrogen atoms in the terrestrial stratosphere, mesosphere and thermosphere. Hot atoms in the atmosphere are produced by solar radiation, the solar wind and various ionic reactions. Nascent hot atoms arise in ground and excited electronic states, and their translational energies are larger by two - three orders of magnitude than the thermal energies of the ambient gas. The relaxation kinetics of hot atoms determines the rate of atmospheric heating, the intensities of aeronomic reactions, and the rate of atom escape from the planet. Modeling of the non-Maxwellian energy distributions of metastable oxygen and nitrogen atoms have been focused on the determination of their impact on the energetics and chemistry of the terrestrial atmosphere between 25 and 250 km . At this altitudes, we have calculated the energy distribution functions of metastable O and N atoms and computed non-equilibrium rates of important aeronomic reactions, such as destruction of the water molecules by O(1D) atoms and production of highly excited nitric oxide molecules. In the upper atmosphere, the metastable O(lD) and N(2D) play important role in formation of the upward atomic fluxes. We have computed the upward fluxes of the metastable and ground state oxygen atoms in the upper atmosphere above 250 km. The accurate distributions of the metastable atoms have been evaluated for the day and night-time conditions.

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 (T dec =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 (V det (theor)=9304 m s -1 versus V det (exp)=9910 m s -1 ) in the range of that of CL-20. Also, the thermal stability (T dec =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.

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

availabilities of their respective food sources (bacteria and fungi ), were also unaffected-or-increasing in soil with CL-20 treatments. This is...ENERGETIC MATERIALS EFFECTS ON ESSENTIAL SOIL PROCESSES: DECOMPOSITION OF ORCHARD...GRASS (DACTYLIS GLOMERATA) LITTER IN SOIL CONTAMINATED WITH ENERGETIC MATERIALS ECBC-TR-1199 Roman G. Kuperman Ronald T. Checkai Michael Simini

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…

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.

Structure, thermodynamic and electronic properties of carbon-nitrogen cubanes and protonated polynitrogen cations

Science.gov (United States)

Chaban, Vitaly V.; Andreeva, Nadezhda A.

2017-12-01

Energy generation and storage are at the center of modern civilization. Energetic materials constitute quite a large class of compounds with a high amount of stored chemical energy that can be released. We hereby use a combination of quantum chemistry methods to investigate feasibility and properties of carbon-nitrogen cubanes and multi-charged polynitrogen cations in the context of their synthesis and application as unprecedented energetic materials. We show that the stored energy increases gradually with the nitrogen content increase. Nitrogen-poor cubanes retain their stabilities in vacuum, even at elevated temperatures. Such molecules will be probably synthesized at some point. In turn, polynitrogen cations are highly unstable, except N8H+, despite they are isoelectronic to all-carbon cubane. Kinetic stability of the cation decays drastically as its total charge increases. High-level thermodynamic calculations revealed that large amounts of energy are liberated upon decompositions of polynitrogen cations, which produce molecular nitrogen, acetylene, and protons. The present results bring a substantial insights to the design of novel high-energy compounds.

Nitrogen-doped Sb-rich Si–Sb–Te phase-change material for high-performance phase-change memory

International Nuclear Information System (INIS)

Zhou, Xilin; Wu, Liangcai; Song, Zhitang; Cheng, Yan; Rao, Feng; Ren, Kun; Song, Sannian; Liu, Bo; Feng, Songlin

2013-01-01

The effects of nitrogen doping on the phase-change performance of Sb-rich Si–Sb–Te materials are systemically investigated, focusing on the chemical state and the role of nitrogen upon crystallization. The tendency of N atoms to bond with Si (SiN x ) in the crystalline film is analyzed by X-ray photoelectron spectroscopy. The microstructures of the materials mixed with Sb 2 Te crystal grains and amorphous Si/SiN x regions are elucidated via in situ transmission electron microscopy, from which a percolation behavior is demonstrated to possibly describe the random crystallization feature in the nucleation-dominated nanocomposite material. The phase-change memory cells based on N-doped Sb-rich Si–Sb–Te materials display more stable and reliable electrical performance than the nitrogen-free ones. An endurance characteristic in the magnitude of 10 7 cycles of the phase-change memory cells is realized with moderate nitrogen addition, meaning that the nitrogen incorporation into Si–Sb–Te material is a suitable method to achieve high-performance phase-change memory for commercial applications

Modeling Thermal Ignition of Energetic Materials

National Research Council Canada - National Science Library

Gerri, Norman J; Berning, Ellen

2004-01-01

This report documents an attempt to computationally simulate the mechanics and thermal regimes created when a threat perforates an armor envelope and comes in contact with stowed energetic material...

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

Reactive thermal waves in energetic materials

Energy Technology Data Exchange (ETDEWEB)

Hill, Larry G [Los Alamos National Laboratory

2009-01-01

Reactive thermal waves (RTWs) arise in several energetic material applications, including self-propagating high-temperature synthesis (SHS), high explosive cookoff, and the detonation of heterogeneous explosives. In this paper I exmaine ideal RTWs, by which I mean that (1) material motion is neglected, (2) the state dependence of reaction is Arrhenius in the temperature, and (3) the reaction rate is modulated by an arbitrary mass-fraction-based reaction progress function. Numerical simulations demonstrate that one's natural intuition, which is based mainly upon experience with inert materials and which leads one to expect diffusion processes to become relatively slow after a short time period, is invalid for high energy, state-sensitive reactive systems. Instead, theory predicts that RTWs can propagate at very high speeds. This result agrees with estimates for detonating heterogeneous explosives, which indicate that RTWs must spread from hot-spot nucleation sites at rates comparable to the detonation speed in order to produce experimentally-observed reaction zone thicknesses. Using dimensionless scaling and further invoking the high activation energy approximation, I obtain an analytic formula for the steady plane RTW speed from numerical calculations. I then compute the RTW speed for real explosives, and discuss aspects of their behavior.

Energetic materials under high pressures and temperatures: stability, polymorphism and decomposition of RDX

International Nuclear Information System (INIS)

Dreger, Z A

2012-01-01

A recent progress in understanding the response of energetic crystal of cyclotrimethylene trinitramine (RDX) to high pressures and temperatures is summarized. The optical spectroscopy and imaging studies under static compression and high temperatures provided new insight into phase diagram, polymorphism and decomposition mechanisms at pressures and temperatures relevant to those under shock compression. These results have been used to aid the understanding of processes under shock compression, including the shock-induced phase transition and identification of the crystal phase at decomposition. This work demonstrates that studies under static compression and high temperatures provide important complementary route for elucidating the physical and chemical processes in shocked energetic crystals.

Strategy for designing stable and powerful nitrogen-rich high-energy materials by introducing boron atoms.

Science.gov (United States)

Wu, Wen-Jie; Chi, Wei-Jie; Li, Quan-Song; Li, Ze-Sheng

2017-06-01

One of the most important aims in the development of high-energy materials is to improve their stability and thus ensure that they are safe to manufacture and transport. In this work, we theoretically investigated open-chain N 4 B 2 isomers using density functional theory in order to find the best way of stabilizing nitrogen-rich molecules. The results show that the boron atoms in these isomers are aligned linearly with their neighboring atoms, which facilitates close packing in the crystals of these materials. Upon comparing the energies of nine N 4 B 2 isomers, we found that the structure with alternating N and B atoms had the lowest energy. Structures with more than one nitrogen atom between two boron atoms had higher energies. The energy of N 4 B 2 increases by about 50 kcal/mol each time it is rearranged to include an extra nitrogen atom between the two boron atoms. More importantly, our results also show that boron atoms stabilize nitrogen-rich molecules more efficiently than carbon atoms do. Also, the combustion of any isomer of N 4 B 2 releases more heat than the corresponding isomer of N 4 C 2 does under well-oxygenated conditions. Our study suggests that the three most stable N 4 B 2 isomers (BN13, BN24, and BN34) are good candidates for high-energy molecules, and it outlines a new strategy for designing stable boron-containing high-energy materials. Graphical abstract The structural characteristics, thermodynamic stabilities, and exothermic properties of nitrogen-rich N 4 B 2 isomers were investigated by means of density functional theory.

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.

A Comparative Density Functional Theory and Density Functional Tight Binding Study of Phases of Nitrogen Including a High Energy Density Material N8

Directory of Open Access Journals (Sweden)

Nicholas Capel

2015-11-01

Full Text Available We present a comparative dispersion-corrected Density Functional Theory (DFT and Density Functional Tight Binding (DFTB-D study of several phases of nitrogen, including the well-known alpha, beta, and gamma phases as well as recently discovered highly energetic phases: covalently bound cubic gauche (cg nitrogen and molecular (vdW-bound N8 crystals. Among several tested parametrizations of N–N interactions for DFTB, we identify only one that is suitable for modeling of all these phases. This work therefore establishes the applicability of DFTB-D to studies of phases, including highly metastable phases, of nitrogen, which will be of great use for modelling of dynamics of reactions involving these phases, which may not be practical with DFT due to large required space and time scales. We also derive a dispersion-corrected DFT (DFT-D setup (atom-centered basis parameters and Grimme dispersion parameters tuned for accurate description simultaneously of several nitrogen allotropes including covalently and vdW-bound crystals and including high-energy phases.

Effects of void anisotropy on the ignition and growth rates of energetic materials

Science.gov (United States)

Rai, Nirmal Kumar; Sen, Oishik; Udaykumar, H. S.

2017-06-01

Initiation of heterogeneous energetic materials is thought to occur at hot spots; reaction fronts propagate from sites of such hot spots into the surrounding material resulting in complete consumption of the material. Heterogeneous materials, such as plastic bonded explosives (PBXs) and pressed materials contain numerous voids, defects and interfaces at which hot spots can occur. Amongst the various mechanisms of hot spot formation, void collapse is considered to be the predominant one in the high strain rate loading conditions. It is established in the past the shape of the voids has a significant effect on the initiation behavior of energetic materials. In particular, void aspect ratio and orientations play an important role in this regard. This work aims to quantify the effects of void aspect ratio and orientation on the ignition and growth rates of chemical reaction from the hot spot. A wide range of aspect ratio and orientations is considered to establish a correlation between the ignition and growth rates and the void morphology. The ignition and growth rates are obtained from high fidelity reactive meso-scale simulations. The energetic material considered in this work is HMX and Tarver McGuire HMX decomposition model is considered to capture the reaction mechanism of HMX. The meso-scale simulations are performed using a Cartesian grid based Eulerian solver SCIMITAR3D. The void morphology is shown to have a significant effect on the ignition and growth rates of HMX.

Europa Lander Material Selection Considerations

Energy Technology Data Exchange (ETDEWEB)

Tappan, Alexander S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Heller, Mellisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-01-10

Energetic materials (EMs, explosives, pyrotechnics, propellants) provide high-power output of high temperature reaction products. These products can be solid, liquid, or gaseous during reaction or after the products have equilibrated with the surroundings. For example, high explosives typically consist of carbon, hydrogen, nitrogen, and oxygen bonded within a single molecule, and produce almost exclusively gaseous products. Conversely, intermetallics consist of physical mixtures of metals and metalloids, and produce almost exclusively condensed products. Other materials such as pyrotechnics and propellants have intermediate behavior. All energetic materials react in a self-propagating manner that after ignition, does not necessarily require energy input from the surroundings. The range of reaction velocities can range from mm/s for intermetallics, to km/s for high explosives. Energetic material selection depends on numerous requirements specific to the needs of a system. High explosives are used for applications where high pressure gases are necessary for pushing or fracturing materials (e.g., rock, metal) or creating shock waves or air blast. Propellants are used to produce moderate-pressure, high-temperature products without a shock wave. Pyrotechnics are used to produce numerous effects including: high-temperature products, gases, light, smoke, sound, and others. Thermites are used to produce heat, high-temperature products, materials, and other effects that require condensed products. Intermetallics are used to produce high-temperature condensed products and materials, with very little gas production. Numerous categories of energetic materials exist with overlapping definitions, effects, and properties.

High-nitrogen explosives

Energy Technology Data Exchange (ETDEWEB)

Naud, D. (Darren); Hiskey, M. A. (Michael A.); Kramer, J. F. (John F.); Bishop, R. L. (Robert L.); Harry, H. H. (Herbert H.); Son, S. F. (Steven F.); Sullivan, G. K. (Gregg K.)

2002-01-01

The syntheses and characterization of various tetrazine and furazan compounds offer a different approach to explosives development. Traditional explosives - such as TNT or RDX - rely on the oxidation of the carbon and hydrogen atoms by the oxygen carrying nitro group to produce the explosive energy. High-nitrogen compounds rely instead on large positive heats of formation for that energy. Some of these high-nitrogen compounds have been shown to be less sensitive to initiation (e.g. by impact) when compared to traditional nitro-containing explosives of similar performances. Using the precursor, 3,6-bis-(3,5-dimethylpyrazol-1-yl)-s-tetrazine (BDT), several useful energetic compounds based on the s-tetrazine system have been synthesized and studied. The compound, 3,3{prime}-azobis(6-amino-s-tetrazine) or DAAT, detonates as a half inch rate stick despite having no oxygen in the molecule. Using perfluoroacetic acid, DAAT can be oxidized to give mixtures of N-oxide isomers (DAAT03.5) with an average oxygen content of about 3.5. This energetic mixture burns at extremely high rates and with low dependency on pressure. Another tetrazine compound of interest is 3,6-diguanidino-s-tetrazine(DGT) and its dinitrate and diperchlorate salts. DGT is easily synthesized by reacting BDT with guanidine in methanol. Using Caro's acid, DGT can be further oxidized to give 3,6-diguanidino-s-tetrazine-1,4-di-N-oxide (DGT-DO). Like DGT, the di-N-oxide can react with nitric acid or perchloric acid to give the dinitrate and the diperchlorate salts. The compounds, 4,4{prime}-diamino-3,3{prime}-azoxyfurazan (DAAF) and 4,4{prime}-diamino-3,3{prime}-azofurazan (DAAzF), may have important future roles in insensitive explosive applications. Neither DAAF nor DAAzF can be initiated by laboratory impact drop tests, yet both have in some aspects better explosive performances than 1,3,5-triamino-2,4,6-trinitrobenzene TATB - the standard of insensitive high explosives. The thermal stability of DAAz

Ultrafast Vibrational Spectrometer for Engineered Nanometric Energetic Materials

National Research Council Canada - National Science Library

Dlott, Dana

2002-01-01

The proposer requested funding for laser equipment that would be used to study engineered nanometric energetic materials consisting of nanometer metal particles, passivation layers and oxidizing binders...

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.

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...

Some new high energy materials and their formulations for specialized applications

Energy Technology Data Exchange (ETDEWEB)

Agrawal, Jai Prakash [Directorate of Materials, DRDO HQrs, ' B' Wing, Sena Bhavan, New Delhi - 110 011 (India)

2005-10-01

Energetic materials form an integral part of most weapon systems and a large number of new high-energy materials: thermally stable explosives, high-performance explosives, melt-castable explosives, insensitive high explosives and energetic binders have been reported in the literature in recent years. Some explosive formulations based on these new energetic materials are also vaguely reported. This paper examines these materials and their formulations from the point of view of stability, reliability, safety and specific applications. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

Nitrogen Doped Macroporous Carbon as Electrode Materials for High Capacity of Supercapacitor

Directory of Open Access Journals (Sweden)

Yudong Li

2017-01-01

Full Text Available Nitrogen doped carbon materials as electrodes of supercapacitors have attracted abundant attention. Herein, we demonstrated a method to synthesize N-doped macroporous carbon materials (NMC with continuous channels and large size pores carbonized from polyaniline using multiporous silica beads as sacrificial templates to act as electrode materials in supercapacitors. By the nice carbonized process, i.e., pre-carbonization at 400 °C and then pyrolysis at 700/800/900/1000 °C, NMC replicas with high BET specific surface areas exhibit excellent stability and recyclability as well as superb capacitance behavior (~413 F ⋅ g−1 in alkaline electrolyte. This research may provide a method to synthesize macroporous materials with continuous channels and hierarchical pores to enhance the infiltration and mass transfer not only used as electrode, but also as catalyst somewhere micro- or mesopores do not work well.

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

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.

Report for MaRIE Drivers Workshop on needs for energetic material's studies.

Energy Technology Data Exchange (ETDEWEB)

Specht, Paul Elliott [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2018-01-01

Energetic materials (i.e. explosives, propellants, and pyrotechnics) have complex mesoscale features that influence their dynamic response. Direct measurement of the complex mechanical, thermal, and chemical response of energetic materials is critical for improving computational models and enabling predictive capabilities. Many of the physical phenomena of interest in energetic materials cover time and length scales spanning several orders of magnitude. Examples include chemical interactions in the reaction zone, the distribution and evolution of temperature fields, mesoscale deformation in heterogeneous systems, and phase transitions. This is particularly true for spontaneous phenomena, like thermal cook-off. The ability for MaRIE to capture multiple length scales and stochastic phenomena can significantly advance our understanding of energetic materials and yield more realistic, predictive models.

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

2017-10-23

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, CO 2 ) 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.

Papers of 5. Scientific-Technical Seminar: Material Study for Electric Power Stations and Energetics

International Nuclear Information System (INIS)

1998-01-01

The review of material research designed for energetic use has been done. The special emphasis have been put on the steels and alloys with desirable mechanical and corrosion properties in high temperature and pressure conditions. The methods for testing and non-destructive diagnostics of materials and welded joints have been also presented and discussed

Energetic salts of the binary 5-cyanotetrazolate anion ([C2N5]-) with nitrogen-rich cations.

Science.gov (United States)

Crawford, Margaret-Jane; Klapötke, Thomas M; Martin, Franz A; Miró Sabaté, Carles; Rusan, Magdalena

2011-02-01

The reaction of cyanogen (NC-CN) with MN(3) (M=Na, K) in liquid SO(2) leads to the formation of the 5-cyanotetrazolate anion as the monohemihydrate sodium (1·1.5 H(2)O) and potassium (2) salts, respectively. Both 1·1.5 H(2)O and 2 were used as starting materials for the synthesis of a new family of nitrogen-rich salts containing the 5-cyanotetrazolate anion and nitrogen-rich cations, namely ammonium (3), hydrazinium (4), semicarbazidium (5), guanidinium (6), aminoguanidinium (7), diaminoguanidinium (8), and triaminoguanidinium (9). Compounds 1-9 were synthesised in good yields and characterised by using analytical and spectroscopic methods. In addition, the crystal structures of 1·1.5 H(2)O, 2, 3, 5, 6, and 9·H(2)O were determined by using low-temperature single-crystal X-ray diffraction. An insight into the hydrogen bonding in the solid state is described in terms of graph-set analysis. Differential scanning calorimetry and sensitivity tests were used to assess the thermal stability and sensitivity against impact and friction of the materials, respectively. For the assessment of the energetic character of the nitrogen-rich salts 3-9, quantum chemical methods were used to determine the constant volume energies of combustion, and these values were used to calculate the detonation velocity and pressure of the salts using the EXPLO5 computer code. Additionally, the performances of formulations of the new compounds with ammonium nitrate and ammonium dinitramide were also predicted. Lastly, the ICT code was used to determine the gases and heats of explosion released upon decomposition of the 5-cyanotetrazolate salts. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Construct 3D porous hollow Co3O4 micro-sphere: A potential oxidizer of nano-energetic materials with superior reactivity

Science.gov (United States)

Wang, Jun; Zheng, Bo; Qiao, Zhiqiang; Chen, Jin; Zhang, Liyuan; Zhang, Long; Li, Zhaoqian; Zhang, Xingquan; Yang, Guangcheng

2018-06-01

High energy density and rapid reactivity are the future trend for nano-energetic materials. Energetic performance of nano-energetic materials depends on the interfacial diffusion and mass transfer during the reacted process. However, the development of desired structure to significantly enhance reactivity still remains challenging. Here we focused on the design and preparation of 3D porous hollow Co3O4 micro-spheres, in which gas-blowing agents (air) and maximize interfacial interactions were introduced to enhance mass transport and reduce the diffusion distance between the oxidizer and fuel (Aluminum). The 3D hierarchical Co3O4/Al based nano-energetic materials show a low-onset decomposition temperature (423 °C), and high heat output (3118 J g-1) resulting from porous and hollow nano-structure of Co3O4 micro-spheres. Furthermore, 3D hierarchical Co3O4/Al arrays were directly fabricated on the silicon substrate, which was fully compatible with silicon-based microelectromechanical systems to achieve functional nanoenergetics-on-a-chip. This approach provides a simple and efficient way to fabricate 3D ordered nano-energetic arrays with superior reactivity and the potential on the application in micro-energetic devices.

Flexible energetic materials and related methods

Energy Technology Data Exchange (ETDEWEB)

Heaps, Ronald J.

2018-03-06

Energetic compositions and methods of forming components from the compositions are provided. In one embodiment, a composition includes aluminum, molybdenum trioxide, potassium perchlorate, and a binder. In one embodiment, the binder may include a silicone material. The materials may be mixed with a solvent, such as xylene, de-aired, shaped and cured to provide a self-supporting structure. In one embodiment, one or more reinforcement members may be added to provide additional strength to the structure. For example, a weave or mat of carbon fiber material may be added to the mixture prior to curing. In one embodiment, blade casting techniques may be used to form a structure. In another embodiment, a structure may be formed using 3-dimensional printing techniques.

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

International Nuclear Information System (INIS)

Zheng Zhaoyang; Zhao Jijun

2016-01-01

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. (topical review)

1-Amine-1,2,3-triazolium salts with oxidizing anions: A new family of energetic materials with good performance

Science.gov (United States)

Zhang, Zhi-Bin; Zhang, Jian-Guo

2018-04-01

A series of 1-amino-1,2,3-triazole (ATZ) based energetic nitrogen-rich salts are prepared by using acid-base neutralization reaction (1:1 M ratio), and fully characterized. Structures of the salts are recrystallized and determined by single-crystal X-ray diffraction, which dominated by a strong hydrogen-bond influence with the densities ranging from 1.692 to 1.868 g cm-3. Thermal behaviors have characterized by using the DSC and TG-DTG technologies. The enthalpies of formation have calculated by using Gaussian 03. The detonation parameters of the salts are determined by using the K-J method, and most salts show promising detonation performances (D: 6699-8231 m s-1, P: 19.2-30.7 GPa), among which the salt of 1-amino-1,2,3-triazolium trinitrophloroglucinate has a detonation properties comparable to RDX. The sensitivities results provided the salts as insensitive energetic materials.

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.

Nitrogen-doped carbon spheres: A new high-energy-density and long-life pseudo-capacitive electrode material for electrochemical flow capacitor.

Science.gov (United States)

Hou, Shujin; Wang, Miao; Xu, Xingtao; Li, Yandong; Li, Yanjiang; Lu, Ting; Pan, Likun

2017-04-01

One of the most challenging issues in developing electrochemical flow capacitor (EFC) technology is the design and synthesis of active electrode materials with high energy density and long cycle life. However, in practical cases, the energy density and cycle ability obtained currently cannot meet the practical need. In this work, we propose a new active material, nitrogen-doped carbon spheres (NCSs), as flowable electrodes for EFC application. The NCSs were prepared via one-pot hydrothermal synthesis in the presence of resorcinol/formaldehyde as carbon precursors and melamine as nitrogen precursor, followed by carbonization in nitrogen flow at various temperatures. The results of EFC experiments demonstrate that NCSs obtained at 800°C exhibit a high energy density of 13.5Whkg -1 and an excellent cycle ability, indicating the superiority of NCSs for EFC application. Copyright © 2016 Elsevier Inc. All rights reserved.

Liquid Nitrogen Removal of Critical Aerospace Materials

Science.gov (United States)

Noah, Donald E.; Merrick, Jason; Hayes, Paul W.

2005-01-01

Identification of innovative solutions to unique materials problems is an every-day quest for members of the aerospace community. Finding a technique that will minimize costs, maximize throughput, and generate quality results is always the target. United Space Alliance Materials Engineers recently conducted such a search in their drive to return the Space Shuttle fleet to operational status. The removal of high performance thermal coatings from solid rocket motors represents a formidable task during post flight disassembly on reusable expended hardware. The removal of these coatings from unfired motors increases the complexity and safety requirements while reducing the available facilities and approved processes. A temporary solution to this problem was identified, tested and approved during the Solid Rocket Booster (SRB) return to flight activities. Utilization of ultra high-pressure liquid nitrogen (LN2) to strip the protective coating from assembled space shuttle hardware marked the first such use of the technology in the aerospace industry. This process provides a configurable stream of liquid nitrogen (LN2) at pressures of up to 55,000 psig. The performance of a one-time certification for the removal of thermal ablatives from SRB hardware involved extensive testing to ensure adequate material removal without causing undesirable damage to the residual materials or aluminum substrates. Testing to establish appropriate process parameters such as flow, temperature and pressures of the liquid nitrogen stream provided an initial benchmark for process testing. Equipped with these initial parameters engineers were then able to establish more detailed test criteria that set the process limits. Quantifying the potential for aluminum hardware damage represented the greatest hurdle for satisfying engineers as to the safety of this process. Extensive testing for aluminum erosion, surface profiling, and substrate weight loss was performed. This successful project clearly

Computational Chemistry Toolkit for Energetic Materials Design

Science.gov (United States)

2006-11-01

industry are aggressively engaged in efforts to develop multiscale modeling and simulation methodologies to model and analyze complex phenomena across...energetic materials design. It is hoped that this toolkit will evolve into a collection of well-integrated multiscale modeling methodologies...Experimenta Theoreticala This Work 1-5-Diamino-4- methyl- tetrazolium nitrate 8.4 41.7 47.5 1-5-Diamino-4- methyl- tetrazolium azide 138.1 161.6

Initial mechanisms for the decomposition of electronically excited energetic materials: 1,5′-BT, 5,5′-BT, and AzTT

International Nuclear Information System (INIS)

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

2015-01-01

Decomposition of nitrogen-rich energetic materials 1,5′-BT, 5,5′-BT, and AzTT (1,5′-Bistetrazole, 5,5′-Bistetrazole, and 5-(5-azido-(1 or 4)H-1,2,4-triazol-3-yl)tetrazole, respectively), following electronic state excitation, is investigated both experimentally and theoretically. The N 2 molecule is observed as an initial decomposition product from the three materials, subsequent to UV excitation, with a cold rotational temperature (<30 K). Initial decomposition mechanisms for these three electronically excited materials are explored at the complete active space self-consistent field (CASSCF) level. Potential energy surface calculations at the CASSCF(12,8)/6-31G(d) level illustrate that conical intersections play an essential role in the decomposition mechanism. Electronically excited S 1 molecules can non-adiabatically relax to their ground electronic states through (S 1 /S 0 ) CI conical intersections. 1,5′-BT and 5,5′-BT materials have several (S 1 /S 0 ) CI conical intersections between S 1 and S 0 states, related to different tetrazole ring opening positions, all of which lead to N 2 product formation. The N 2 product for AzTT is formed primarily by N–N bond rupture of the –N 3 group. The observed rotational energy distributions for the N 2 products are consistent with the final structures of the respective transition states for each molecule on its S 0 potential energy surface. The theoretically derived vibrational temperature of the N 2 product is high, which is similar to that found for energetic salts and molecules studied previously

Ultrafast Vibrational Spectrometer for Engineered Nanometric Energetic Materials

National Research Council Canada - National Science Library

Dlott, Dana

2002-01-01

.... The needed equipment was ordered and installed, and assembled into a working SFG set up that has been tested on a model system consisting of a self assembled monolayer of alkane on gold. The next step will be to finish integrating the carbon dioxide laser system and to begin looking at aluminum based energetic materials.

To the problem of structural materials serviceability in nitrogen-hydrogen-containing environments

International Nuclear Information System (INIS)

Bichuya, A.L.

1982-01-01

The analysis of the factors which affect high-temperature serviceability of structural materials in nitrogen-hydrogen-containing environments, in particular in ammonia, has been carried out on the basis of the published and own experimental data. It is shown that the observed reduction of serviceability of structural materials, under the effect of high temperatures and nitrogen-hydrogen-containing environments, can occur as a result of corrosion failure connected with nitriding, and also hydrogen embrittlement appearing as a result of the penetration of hydrogen formed during adsorbed gaseous phase dissociation on the metal being deformed. The suggested scheme of high-temperature metal fracture under the effect of nitrogen-hydrogen-containing environments, that in contrast to the previous ones includes the factor of hydrogen ebrittlement, allows to give a real estimation of structional materials serviceability under product service conditions

Molecular Modeling of Energetic Materials: The Parameterization and Validation of Nitrate Esters in the COMPASS Force Field

National Research Council Canada - National Science Library

Bunte, Steven

2000-01-01

To investigate the mechanical and other condensed phase properties of energetic materials using atomistic simulation techniques, the COMPASS force field has been expanded to include high-energy nitro functional groups...

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

Carbon materials-functionalized tin dioxide nanoparticles toward robust, high-performance nitrogen dioxide gas sensor.

Science.gov (United States)

Zhang, Rui; Liu, Xiupeng; Zhou, Tingting; Wang, Lili; Zhang, Tong

2018-08-15

Carbon (C) materials, which process excellent electrical conductivity and high carrier mobility, are promising sensing materials as active units for gas sensors. However, structural agglomeration caused by chemical processes results in a small resistance change and low sensing response. To address the above issues, structure-derived carbon-coated tin dioxide (SnO 2 ) nanoparticles having distinct core-shell morphology with a 3D net-like structure and highly uniform size are prepared by careful synthesis and fine structural design. The optimum carbon-coated SnO 2 nanoparticles (SnO 2 /C)-based gas sensor exhibits a low working temperature, excellent selectivity and fast response-recovery properties. In addition, the SnO 2 /C-based gas sensor can maintain a sensitivity to nitrogen dioxide (NO 2 ) of 3 after being cycled 4 times at 140 °C for, suggesting its good long-term stability. The structural integrity, good synergistic properties, and high gas-sensing performance of SnO 2 /C render it a promising sensing material for advanced gas sensors. Copyright © 2018 Elsevier Inc. All rights reserved.

High-resolution simulations of cylindrical void collapse in energetic materials: Effect of primary and secondary collapse on initiation thresholds

Science.gov (United States)

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

2017-04-01

Void collapse in energetic materials leads to hot spot formation and enhanced sensitivity. Much recent work has been directed towards simulation of collapse-generated reactive hot spots. The resolution of voids in calculations to date has varied as have the resulting predictions of hot spot intensity. Here we determine the required resolution for reliable cylindrical void collapse calculations leading to initiation of chemical reactions. High-resolution simulations of collapse provide new insights into the mechanism of hot spot generation. It is found that initiation can occur in two different modes depending on the loading intensity: Either the initiation occurs due to jet impact at the first collapse instant or it can occur at secondary lobes at the periphery of the collapsed void. A key observation is that secondary lobe collapse leads to large local temperatures that initiate reactions. This is due to a combination of a strong blast wave from the site of primary void collapse and strong colliding jets and vortical flows generated during the collapse of the secondary lobes. The secondary lobe collapse results in a significant lowering of the predicted threshold for ignition of the energetic material. The results suggest that mesoscale simulations of void fields may suffer from significant uncertainty in threshold predictions because unresolved calculations cannot capture the secondary lobe collapse phenomenon. The implications of this uncertainty for mesoscale simulations are discussed in this paper.

Study of thermal sensitivity and thermal explosion violence of energetic materials in the LLNL ODTX system

International Nuclear Information System (INIS)

Hsu, P C; Hust, G; Zhang, M X; Lorenz, T K; Reynolds, J G; Fried, L; Springer, H K; Maienschein, J L

2014-01-01

Incidents caused by fire and combat operations can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Some explosives may thermally explode at fairly low temperatures (< 100 °C) and the violence from thermal explosion may cause significant damage. Thus it is important to understand the response of energetic materials to thermal insults. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory has been used for decades to measure times to explosion, threshold thermal explosion temperature, and determine kinetic parameters of energetic materials. Samples of different configurations (pressed part, powder, paste, and liquid) can be tested in the system. The ODTX testing can also provide useful data for assessing the thermal explosion violence of energetic materials. Recent ODTX experimental data are reported in the paper.

Use of energetic ion beams in materials synthesis and processing

International Nuclear Information System (INIS)

Appleton, B.R.

1992-01-01

A brief review of the use energetic ion beams and related techniques for the synthesis, processing, and characterization of materials is presented. Selected opportunity areas are emphasized with examples, and references are provided for more extensive coverage. (author)

Enhancing Reactivity in Structural Energetic Materials

Science.gov (United States)

Glumac, Nick

2017-06-01

In many structural energetic materials, only a small fraction of the metal oxidizes, and yet this provides a significant boost in the overall energy release of the system. Different methodologies to enhance this reactivity include alloying and geometric modifications of microstructure of the reactive material (RM). In this presentation, we present the results of several years of systematic study of both chemical (alloy) and mechanical (geometry) effects on reactivity for systems with typical charge to case mass ratios. Alloys of aluminum with magnesium and lithium are considered, as these are common alloys in aerospace applications. In terms of geometric modifications, we consider surface texturing, inclusion of dense additives, and inclusion of voids. In all modifications, a measurable influence on output is observed, and this influence is related to the fragment size distribution measured from the observed residue. Support from DTRA is gratefully acknowledged.

Thermal Energetic Reactor with High Reproduction of Fission Materials

International Nuclear Information System (INIS)

Kotov, V.M.

2012-01-01

Existing thermal reactors are energy production scale limited because of low portion of raw uranium usage. Fast reactors are limited by reprocessing need of huge mass of raw uranium at the initial stage of development. The possibility of development of thermal reactors with high fission materials reproduction, which solves the problem, is discussed here. Neutron losses are decreased, uranium-thorium fuel with artificial fission materials equilibrium regime is used, additional in-core and out-core neutron sources are used for supplying of high fission materials reproduction. Liquid salt reactors can use dynamic loading regime for this purpose. Preferable construction is channel type reactor with heavy water moderator. Good materials for fuel element shells and channel walls are zirconium alloys enriched by 90Zr. Water cooled reactors with usage 12% of raw uranium and liquid metal cooled reactors with usage 25% of raw uranium are discussed. Reactors with additional neutron sources obtain full usage of raw uranium with small additional energy expenses. 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.

Advanced carbon-based material C60 modification using partially ionized cluster and energetic beams

International Nuclear Information System (INIS)

Du Yuancheng; Ren Zhongmin; Ning Zhifeng; Xu Ning; Li Fuming

1997-01-01

Two processes have been undertaken using Partially ionized cluster deposition (PICBD) and energetic ion bombardment beams deposition (IBD) respectively. C 60 films deposited by PICBD at V=0 and 65 V, which result in highly textured close-packed structure in orientation (110) and being more polycrystalline respectively, the resistance of C 60 films to oxygen diffusion contamination will be improved. In the case of PICBD, the ionized C 60 soccer-balls molecules in the evaporation beams will be fragmented in collision with the substrate under the elevated accelerating fields Va. As a new synthetic IBD processing, two low energy (400 and 1000 eV) nitrogen ion beams have been used to bombard C 60 films to synthesize the carbon nitride films

Nitrogen-doped hierarchical porous carbon materials prepared from meta-aminophenol formaldehyde resin for supercapacitor with high rate performance

International Nuclear Information System (INIS)

Zhou, Jin; Zhang, Zhongshen; Xing, Wei; Yu, Jing; Han, Guoxing; Si, Weijiang; Zhuo, Shuping

2015-01-01

Graphical abstract: N-doped hierarchical porous carbons with high rate capacitive performance are prepared by a combination method of nano-SiO 2 template/KOH activation. - Highlights: • A mass produced nano-SiO 2 is used to prepared hierarchical porous carbon. • N-doped hierarchical porous carbon materials are easily prepared. • The NHPCs materials exhibit a very high capacitance of up to 260.5 F g −1 . • The NHPC-800 sample shows very high rate capability. • Hierarchical porosity and N-doping synergistically enhances the whole capacitance. - Abstract: In this work, nitrogen-doped hierarchical porous carbon materials (NHPCs) are prepared by a two-step method combined of a hard template process and KOH-activation treatment. Low cost and large-scale commercial nano-SiO 2 are used as a hard template. The hierarchical porosity, structure and nitrogen-doped surface chemical properties are proved by a varies of means, such as scanning electron microscopy, transition electron microscopy, N 2 sorption, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. When the prepared NHPCs materials are used as the electrode materials for supercapacitors in KOH electrolyte, they exhibit very high specific capacitance, good power capability and excellent cyclic stability. NHPC-800 carbon shows a high capacitance of 114.0 F g −1 at the current density of 40 A g −1 , responding to a high energy and power densities of 4.0 Wh kg −1 and 10 000 W kg −1 , and a very short drain time of 1.4 s. The excellent capacitive performance may be due to the synergistic effect of the hierarchical porosity, high effective surface area and heteroatom doping, resulting in both electrochemical double layer and Faradaic capacitance contributions

2007 Insensitive Munitions and Energetic Materials Technology Symposium

Science.gov (United States)

2007-10-18

Assessment – EIPT chair rotates each calendar year between NAVAIR and NAVSEA Page 9 Networks for collaboration Technology Oriented: Energetic Materials...Analysis IM Explosive Fill for 120mm and/or 155mm Arena Test & Qualificationr t lifi ti Must Show Improvement Review of Filter 1 Data for 3...Arena Test & Qualificationr t lifi ti Must Show Improvement PM-CAS Common Low-cost IM Explosives Program “Funnel” framework to progressively screen

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.

Novel porous carbon materials with ultrahigh nitrogen contents for selective CO 2 capture

KAUST Repository

Zhao, Yunfeng; Zhao, Lan; Yao, Kexin; Yang, Yang; Zhang, Qiang; Han, Yu

2012-01-01

Nitrogen-doped carbon materials were prepared by a nanocasting route using tri-continuous mesoporous silica IBN-9 as a hard template. Rationally choosing carbon precursors and carefully controlling activation conditions result in an optimized material denoted as IBN9-NC1-A, which possesses a very high nitrogen doping concentration (∼13 wt%) and a large surface area of 890 m 2 g -1 arising from micropores (<1 nm). It exhibits an excellent performance for CO 2 adsorption over a wide range of CO 2 pressures. Specifically, its equilibrium CO 2 adsorption capacity at 25 °C reaches up to 4.50 mmol g -1 at 1 bar and 10.53 mmol g -1 at 8 bar. In particular, it shows a much higher CO 2 uptake at low pressure (e.g. 1.75 mmol g -1 at 25 °C and 0.2 bar) than any reported carbon-based materials, owing to its unprecedented nitrogen doping level. The high nitrogen contents also give rise to significantly enhanced CO 2/N 2 selectivities (up to 42), which combined with the high adsorption capacities, make these new carbon materials promising sorbents for selective CO 2 capture from power plant flue gas and other relevant applications. © 2012 The Royal Society of Chemistry.

Theoretical Studies of Small-System Thermodynamics in Energetic Materials

Science.gov (United States)

2016-01-06

SECURITY CLASSIFICATION OF: This is a comprehensive theoretical research program to investigate the fundamental principles of small-system thermodynamics ...a.k.a. nanothermodynamics). The proposed work is motivated by our desire to better understand the fundamental dynamics and thermodynamics of...for Public Release; Distribution Unlimited Final Report: Theoretical Studies of Small-System Thermodynamics in Energetic Materials The views, opinions

Nitrogen-doped porous carbon derived from biomass waste for high-performance supercapacitor.

Science.gov (United States)

Ma, Guofu; Yang, Qian; Sun, Kanjun; Peng, Hui; Ran, Feitian; Zhao, Xiaolong; Lei, Ziqiang

2015-12-01

High capacitance property and low cost are the pivotal requirements for practical application of supercapacitor. In this paper, a low cost and high capacitance property nitrogen-doped porous carbon with high specific capacitance is prepared. The as-prepared nitrogen-doped porous carbon employing potato waste residue (PWR) as the carbon source, zinc chloride (ZnCl2) as the activating agent and melamine as nitrogen doping agent. The morphology and structure of the carbon materials are studied by scanning electron microscopy (SEM), N2 adsorption/desorption, X-ray diffraction (XRD) and Raman spectra. The surface area of the nitrogen-doped carbon which prepared under 700°C is found to be 1052m(2)/g, and the specific capacitance as high as 255Fg(-1) in 2M KOH electrolyte is obtained utilize the carbon as electrode materials. The electrode materials also show excellent cyclability with 93.7% coulombic efficiency at 5Ag(-1) current density of for 5000cycles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Radiation Shielding Materials Containing Hydrogen, Boron, and Nitrogen: Systematic Computational and Experimental Study. Phase I

Science.gov (United States)

Thibeault, Sheila A.; Fay, Catharine C.; Lowther, Sharon E.; Earle, Kevin D.; Sauti, Godfrey; Kang, Jin Ho; Park, Cheol; McMullen, Amelia M.

2012-01-01

The key objectives of this study are to investigate, both computationally and experimentally, which forms, compositions, and layerings of hydrogen, boron, and nitrogen containing materials will offer the greatest shielding in the most structurally robust combination against galactic cosmic radiation (GCR), secondary neutrons, and solar energetic particles (SEP). The objectives and expected significance of this research are to develop a space radiation shielding materials system that has high efficacy for shielding radiation and that also has high strength for load bearing primary structures. Such a materials system does not yet exist. The boron nitride nanotube (BNNT) can theoretically be processed into structural BNNT and used for load bearing structures. Furthermore, the BNNT can be incorporated into high hydrogen polymers and the combination used as matrix reinforcement for structural composites. BNNT's molecular structure is attractive for hydrogen storage and hydrogenation. There are two methods or techniques for introducing hydrogen into BNNT: (1) hydrogen storage in BNNT, and (2) hydrogenation of BNNT (hydrogenated BNNT). In the hydrogen storage method, nanotubes are favored to store hydrogen over particles and sheets because they have much larger surface areas and higher hydrogen binding energy. The carbon nanotube (CNT) and BNNT have been studied as potentially outstanding hydrogen storage materials since 1997. Our study of hydrogen storage in BNNT - as a function of temperature, pressure, and hydrogen gas concentration - will be performed with a hydrogen storage chamber equipped with a hydrogen generator. The second method of introducing hydrogen into BNNT is hydrogenation of BNNT, where hydrogen is covalently bonded onto boron, nitrogen, or both. Hydrogenation of BN and BNNT has been studied theoretically. Hyper-hydrogenated BNNT has been theoretically predicted with hydrogen coverage up to 100% of the individual atoms. This is a higher hydrogen content

A multi-scale methodology to model damage, deformation and ignition of highly-filled energetic materials

Energy Technology Data Exchange (ETDEWEB)

Vivier, G. [Paris Univ., Paris (France). LMT Cachan; CEA Le Ripault, Monts (France); Trumel, H. [CEA Le Ripault, Monts (France); Hild, F. [Paris Univ., Paris (France). LMT Cachan

2009-07-01

The kinetic energy that occurs when energetic materials are impacted can be converted to heat through dissipative deformation processes while the macroscopic temperature remains unaffected. In this study, a thermodynamics-based approach was used to model the elasto-plastic behaviour that occurs during the deformation process of microstructures. Macroscopic material was modelled as a statistical distribution of unit cells containing a crack grain embedded in an elastic mortar-like matrix. A mesoscopic unit cell model was also developed under confined shear. The study demonstrated that stored energy is a non-negligible part of the total energy of the system, and that stored energy can be released during the unloading process. It was concluded that the mesoscopic analysis of the cracked cell demonstrates that continuum thermodynamics can be used to predict hot spots induced by friction. 7 refs., 7 figs.

Shock interactions with heterogeneous energetic materials

Science.gov (United States)

Yarrington, Cole D.; Wixom, Ryan R.; Damm, David L.

2018-03-01

The complex physical phenomenon of shock wave interaction with material heterogeneities has significant importance and nevertheless remains little understood. In many materials, the observed macroscale response to shock loading is governed by characteristics of the microstructure. Yet, the majority of computational studies aimed at predicting phenomena affected by these processes, such as the initiation and propagation of detonation waves in explosives or shock propagation in geological materials, employ continuum material and reactive burn model treatment. In an effort to highlight the grain-scale processes that underlie the observable effects in an energetic system, a grain-scale model for hexanitrostilbene (HNS) has been developed. The measured microstructures were used to produce synthetic computational representations of the pore structure, and a density functional theory molecular dynamics derived equation of state (EOS) was used for the fully dense HNS matrix. The explicit inclusion of the microstructure along with a fully dense EOS resulted in close agreement with historical shock compression experiments. More recent experiments on the dynamic reaction threshold were also reproduced by inclusion of a global kinetics model. The complete model was shown to reproduce accurately the expected response of this heterogeneous material to shock loading. Mesoscale simulations were shown to provide a clear insight into the nature of threshold behavior and are a way to understand complex physical phenomena.

Three Dimensional Nitrogen-Doped and Nitrogen, Sulfur-Codoped Graphene Hydrogels for Electrode Materials in Supercapacitors.

Science.gov (United States)

Yuan, Zhao; Qiao, Fei; Wang, Guiqiang; Zhou, Jin; Cui, Hongyou; Zhuo, Shuping; Xing, Ling-Bao

2018-08-01

In present work, reduced graphene oxide hydrogels (RGOHs) with three-dimensional (3D) porous structure are prepared through chemical reduction method by using aminourea (NRGOHs) and aminothiourea (NSRGOHs) as reductants. The as-prepared RGOHs are considered not only as promising electrode materials for supercapacitors, but also the doping of nitrogen (aminourea, NRGOHs) or nitrogen/sulfur (aminothiourea, NSRGOHs) can improve electrochemical performance through faradaic pseudocapacitance. The optimized samples have been prepared by controlling the mass ratios of graphene oxide (GO) to aminourea or aminothiourea to be 1:1, 1:2 and 1:5, respectively. With adding different amounts of aminourea or aminothiourea, the obtained RGOHs exhibited different electrochemical performance in supercapacitors. With increasing the dosage of the reductants, the RGOHs revealed better specific capacitances. Moreover, NSRGOHs with nitrogen, sulfur-codoping exhibited better capacitance performance than that of NRGOHs with only nitrogen-doping. NSRGOHs showed excellent capacitive performance with a very high specific capacitance up to 232.2, 323.3 and 345.6 F g-1 at 0.2 A g-1, while NRGOHs showed capacitive performance with specific capacitance up to 220.6, 306.5 and 332.7 F g-1 at 0.2 A g-1. This provides a strategy to improve the capacitive properties of RGOHs significantly by controlling different doping the materials.

Study on Energetic Ions Behavior in Plasma Facing Materials at Lower Temperature

International Nuclear Information System (INIS)

Morimoto, Y.; Sugiyama, T.; Akahori, S.; Kodama, H.; Tega, E.; Sasaki, M.; Oyaidu, M.; Kimura, H.; Okuno, K.

2003-01-01

An apparatus equipped with X-ray Photoelectron Spectroscopy (XPS) and Thermal Desorption Spectroscopy (TDS) was constructed to study interactions of energetic hydrogen isotopes with plasma facing materials. It is a remarkable feature of the apparatus that energetic ion implantation is carried out at around 150K to study reactions of energetic ions with matrix by suppressing the reactions of thermalized ions. Using this apparatus, TDS experiments for pyrolytic graphite implanted with energetic D 2 ions at 173 and 373K were carried out. The experimental results suggest that the deuterium implanted was released through a four-step release processes, involving three D 2 and one CD x (x = 2, 3 and 4) desorption processes. Two deuterium and CD x desorption processes were observed in the temperature range from 700 to 1200 K. In addition, a new deuterium desorption process was observed for the deuterium-implanted sample at 173 K. This has never been observed for deuterium-implanted graphite implanted at temperatures higher than room temperature

Experimental flame speed in multi-layered nano-energetic materials

Energy Technology Data Exchange (ETDEWEB)

Manesh, Navid Amini; Basu, Saptarshi; Kumar, Ranganathan [Department of Mechanical, Material and Aerospace Engineering, University of Central Florida, Orlando, FL (United States)

2010-03-15

This paper deals with the reaction of dense Metastable Intermolecular Composite (MIC) materials, which have a higher density than conventional energetic materials. The reaction of a multilayer thin film of aluminum and copper oxide has been studied by varying the substrate material and thicknesses. The in-plane speed of propagation of the reaction was experimentally determined using a time of- flight technique. The experiment shows that the reaction is completely quenched for a silicon substrate having an intervening silica layer of less than 200 nm. The speed of reaction seems to be constant at 40 m/s for silica layers with a thickness greater than 1 {mu}m. Different substrate materials such as glass and photoresist were also used. (author)

High Energy Cutting and Stripping Utilizing Liquid Nitrogen

Science.gov (United States)

Hume, Howard; Noah, Donald E.; Hayes, Paul W.

2005-01-01

The Aerospace Industry has endeavored for decades to develop hybrid materials that withstand the rigors of mechanized flight both within our atmosphere and beyond. The development of these high performance materials has led to the need for environmentally friendly technologies for material re-work and removal. The NitroJet(TM) is a fluid jet technology that represents an evolution of the widely used, large-scale water jet fluid jet technology. It involves the amalgamation of fluid jet technology and cryogenics technology to create a new capability that is applicable where water jet or abrasive jet (water jet plus entrained abrasive) are not suitable or acceptable because of technical constraints such as process or materials compatibility, environmental concerns and aesthetic or legal requirements. The NitroJet(TM) uses ultra high-pressure nitrogen to cut materials, strip numerous types of coatings such as paint or powder coating, clean surfaces and profile metals. Liquid nitrogen (LN2) is used as the feed stream and is pressurized in two stages. The first stage pressurizes sub cooled LN2 to an intermediate pressure of between 15,000 and 20,000 psi at which point the temperature of the LN2 is about -250 F. The discharge from this stage is then introduced as feed to a dual intensifier system, which boosts the pressure from 15,000 - 20,000 psi up to the maximum operating pressure of 55,000 psi. A temperature of about -220 F is achieved at which point the nitrogen is supercritical. In this condition the nitrogen cuts, strips and abrades much like ultra high-pressure water would but without any residual liquid to collect, remove or be contaminated. Once the nitrogen has performed its function it harmlessly flashes back into the atmosphere as pure nitrogen gas. The system uses heat exchangers to control and modify the temperature of the various intake and discharge nitrogen streams. Since the system is hydraulically operated, discharge pressures can be easily varied over

High nitrogen stainless steels for nuclear industry

International Nuclear Information System (INIS)

Kamachi Mudali, U.

2016-01-01

Nitrogen alloying in stainless steels (SS) has myriad beneficial effects, including solid solution strengthening, precipitation effects, phase control and corrosion resistance. Recent years have seen a rapid development of these alloys with improved properties owing to advances in processing technologies. Furthermore, unlimited demands for high-performance advanced steels for special use in advanced applications renewed the interest in high nitrogen steels (HNS). The combination of numbers of attractive properties such as strength, fracture toughness, wear resistance, workability, magnetic properties and corrosion resistance of HNS has given a unique advantage and offers a number of prospective applications in different industries. Based on extensive studies carried out at IGCAR, nitrogen alloyed type 304LN SS and 316LN SS have been chosen as materials of construction for many engineering components of fast breeder reactor (FBR) and associated reprocessing plants. HNS austenitic SS alloys are used as structural/reactor components, i.e., main vessel, inner vessel, control plug, intermediate heat exchanger and main sodium piping for fast breeder reactor. HNS type 304LN SS is a candidate material for continuous dissolver, nuclear waste storage tanks, pipings, etc. for nitric acid service under highly corrosive conditions. Recent developments towards the manufacturing and properties of HNS alloys for application in nuclear industry are highlighted in the presentation. (author)

High energy ions and energetic plasma irradiation effects on aluminum in a Filippov-type plasma focus

Energy Technology Data Exchange (ETDEWEB)

Roshan, M.V. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore)], E-mail: mroshan20@yahoo.com; Rawat, R.S. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Babazadeh, A.R.; Emami, M.; Sadat Kiai, S.M. [Plasma Physics Research Center, AEOI, 14155-1339 Tehran (Iran, Islamic Republic of); Verma, R.; Lin, J.J.; Talebitaher, A.R.; Lee, P.; Springham, S.V. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore)

2008-12-30

High energy ions and energetic plasma irradiation of aluminum cathode inserts have been accomplished in nitrogen and argon filled plasma focus device. The Filippov-type plasma focus facility, Dena, with 288 {mu}F capacitor bank and charging voltage of 25 kV (90 kJ maximum storage energy) was first optimized for strong ion beam generation for nitrogen and argon gases by maximizing hard X-ray emission efficiency. X-ray diffraction analysis as well as scanning electron microscopy along with energy dispersive X-ray spectroscopy carried out to study the structural, morphological and compositional profile of the treated samples. Change in preferred orientation, emergence of meta-stable phases, generation of copper micro-droplets, and production of cracks across the sample are demonstrated and discussed. The micro-hardness measurements in Vickers scale reveal that after ion irradiation, the surface hardness of samples is reduced.

The viability and performance characterization of nano scale energetic materials on a semiconductor bridge (SCB)

Science.gov (United States)

Strohm, Gianna Sophia

The move from conventional energetic composites to nano scale energetic mixtures (nano energetics) has shown dramatic improvement in energy release rate and sensitivity to ignition. A possible application of nano energetics is on a semiconductor bridge (SCB). An SCB typically requires a tenth of the energy input as compared to a bridge wire design with the same no-fire and is capable of igniting in tens of microseconds. For very low energy applications, SCBs can be manufactured to extremely small sizes and it is necessary to find materials with particle sizes that are even smaller to function. Reactive particles of comparable size to the bridge can lead to problems with ignition reliability for small bridges. Nano-energetic composites and the use of SCBs have been significantly studied individually, however, the process of combining nano energetics with an SCB has not been investigated extensively and is the focus of this work. Goals of this study are to determine if nano energetics can be used with SCBs to further reduce the minimum energy required and improve reliability. The performance of nano-scale aluminum (nAl) and bismuth oxide (Bi2O3) with nitrocellulose (NC), Fluorel(TM) FC 2175 (chemically equivalent to VitonRTM) and Glycidyl Azide Polymer (GAP) as binders where quantified initially using the SenTest(TM) algorithm at three weight fractions (5, 7, and 9%) of binder. The threshold energy was calculated and compared to previous data using conventional materials such as zirconium potassium chlorate (ZPC), mercuric 5-Nitrotetrazol (DXN-1) and titanium sub-hydride potassium per-chlorate (TSPP). It was found that even though there where only slight differences in performance between the binders with nAl/Bi2O 3 at any of the three binder weight fractions, the results show that these nano energetic materials require about half of the threshold energy compared to conventional materials using an SCB with an 84x42 mum bridge. Binder limit testing was conducted to

Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

International Nuclear Information System (INIS)

Shpotyuk, O.

1997-01-01

The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author)

Nitrogen/Sulfur-Codoped Carbon Materials from Chitosan for Supercapacitors

Science.gov (United States)

Li, Mei; Han, Xianlong; Chang, Xiaoqing; Yin, Wenchao; Ma, Jingyun

2016-08-01

d-Methionine and chitosan have been used for fabrication of nitrogen/sulfur-codoped carbon materials by a hydrothermal process followed by carbonization at 750°C for 3 h. The as-prepared carbon materials showed enhanced electrochemical performance, combining electrical double-layer capacitance with pseudocapacitance owing to the doping with sulfur and nitrogen. The specific capacitance of the obtained carbon material reached 135 F g-1 at current density of 1 A g-1, which is much higher than undoped chitosan (67 F g-1). The capacitance retention of the carbon material was almost 97.2% after 5000 cycles at current density of 1 A g-1. With such improved electrochemical performance, the nitrogen/sulfur-codoped carbon material may have promising potential for use in energy-storage electrodes of supercapacitors.

Nitrogen-Doped Carbon Nanotube and Graphene Materials for Oxygen Reduction Reactions

Directory of Open Access Journals (Sweden)

Qiliang Wei

2015-09-01

Full Text Available Nitrogen-doped carbon materials, including nitrogen-doped carbon nanotubes (NCNTs and nitrogen-doped graphene (NG, have attracted increasing attention for oxygen reduction reaction (ORR in metal-air batteries and fuel cell applications, due to their optimal properties including excellent electronic conductivity, 4e− transfer and superb mechanical properties. Here, the recent progress of NCNTs- and NG-based catalysts for ORR is reviewed. Firstly, the general preparation routes of these two N-doped carbon-allotropes are introduced briefly, and then a special emphasis is placed on the developments of both NCNTs and NG as promising metal-free catalysts and/or catalyst support materials for ORR. All these efficient ORR electrocatalysts feature a low cost, high durability and excellent performance, and are thus the key factors in accelerating the widespread commercialization of metal-air battery and fuel cell technologies.

Investigation of structural materials of reactors using high-energy heavy-ion irradiations

International Nuclear Information System (INIS)

Wang Zhiguang

2007-01-01

Radiation damage in structural materials of fission/fusion reactors is mainly attributed to the evolution of intensive atom displacement damage induced by energetic particles (n, α and/or fission fragments) and high-rate helium doping by direct α particle bombardments and/or (n, α) reactions. It can cause severe degradation of reactor structural materials such as surface blistering, bulk void swelling, deformation, fatigue, embrittlement, stress erosion corrosion and so on that will significantly affect the operation safety of reactors. However, up to now, behavior of structural materials at the end of their service can hardly be fully tested in a real reactor. In the present work, damage process in reactor structural materials is briefly introduced, then the advantages of energetic ion implantation/irradiation especially high-energy heavy ion irradiation are discussed, and several typical examples on simulation of radiation effects in reactor candidate structural materials using high-energy heavy ion irradiations are pronounced. Experimental results and theoretical analysis suggested that irradiation with energetic particles especially high-energy heavy ions is very useful technique for simulating the evolution of microstructures and macro-properties of reactor structural materials. Furthermore, an on-going plan of material irradiation experiments using high energy H- and He-ions based on the Heavy Ion Research Facilities in Lanzhou (HIRFL) is also briefly interpreted. (authors)

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

International Nuclear Information System (INIS)

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

1994-01-01

LLNL has built a small-scale (about 1 kg/hr throughput unit to test the destruction of energetic materials using the Molten Salt Destruction (MSD) process. We have modified the unit described in the earlier references to inject energetic waste material continuously into the unit. In addition to the HMX, other explosives we have destroyed include RDX, PETN, ammonium picrate, TNT, nitroguanadine, and TATB. We have also destroyed a liquid gun propellant comprising hydroxyl ammonium nitrate, triethanolammonium nitrate and water. In addition to these pure components, we have destroyed a number of commonly used formulations, such as LX-10 (HMX/Viton), LX-16 (PETN/FPC461, LX-17 (TATB/Kel F), and PBX-9404 (HMX)/CEF/Nitro cellulose). Our experiments have demonstrated that energetic materials can be safely and effectively treated by MSD.We have also investigated the issue of steam explosions in molten salt units, both experimentally and theoretically, and concluded that steam explosions can be avoided under proper design and operating conditions. We are currently building a larger unit (nominal capacity 5 kg/hr,) to investigate the relationship between residence time, temperature, feed concentration and throughputs, avoidance of back-burn, a;nd determination of the products of combustion under different operating conditions

High rate capability of TiO{sub 2}/nitrogen-doped graphene nanocomposite as an anode material for lithium–ion batteries

Energy Technology Data Exchange (ETDEWEB)

Cai, Dandan; Li, Dongdong; Wang, Suqing [School of Chemistry and Chemical Engineering, South China University of Technology, Wushan Road, Guangzhou (China); Zhu, Xuefeng; Yang, Weishen [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian (China); Zhang, Shanqing [Centre for Clean Environment and Energy, Environmental Futures Centre and Griffith School of Environment, Gold Coast Campus, Griffith University, QLD 4222 (Australia); Wang, Haihui, E-mail: hhwang@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Wushan Road, Guangzhou (China)

2013-06-05

Highlights: ► TiO{sub 2}/N-doped graphene composite was synthesized by a gas/liquid interfacial method. ► The nanocomposite was used to fabricate lithium-ion batteries. ► Its electrochemical performance was evaluated for the first time. ► The anode material exhibits a good cycling performance and rate capability. -- Abstract: TiO{sub 2}/nitrogen-doped graphene nanocomposite was synthesized by a facile gas/liquid interface reaction. The structure and morphology of the sample were analyzed by X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The results indicate that nitrogen atoms were successfully doped into graphene sheets. The TiO{sub 2} nanoparticles (8–13 nm in size) were homogenously anchored on the nitrogen-doped graphene sheets through gas/liquid interface reaction. The as-prepared TiO{sub 2}/nitrogen-doped graphene nanocomposite shows a better electrochemical performance than the TiO{sub 2}/graphene nanocomposite and the bare TiO{sub 2} nanoparticles. TiO{sub 2}/nitrogen-doped graphene nanocomposite exhibits excellent cycling stability and shows high capacity of 136 mAh g{sup −1} (at a current density of 1000 mA g{sup −1}) after 80 cycles. More importantly, a high reversible capacity of 109 mAh g{sup −1} can still be obtained even at a super high current density of 5000 mA g{sup −1}. The superior electrochemical performance is attributed to the good electronic conductivity introduced by the nitrogen-doped graphene sheets and the positive synergistic effect between nitrogen-doped graphene sheets and TiO{sub 2} nanoparticles.

One-pot synthesis of nitrogen and sulfur co-doped graphene supported MoS2 as high performance anode materials for lithium-ion batteries

International Nuclear Information System (INIS)

Liu, Qiuhong; Wu, Zhenjun; Ma, Zhaoling; Dou, Shuo; Wu, Jianghong; Tao, Li; Wang, Xin; Ouyang, Canbing; Shen, Anli; Wang, Shuangyin

2015-01-01

Highlights: • Nitrogen and sulfur co-doped graphene supported MoS 2 nanosheets were successfully prepared and used as anode materials for Li-ion batteries. • The as-prepared anode materials show excellent stability in Li-ion batteries. • The materials show high reversible capacity for lithium ion batteries. - Abstract: Nitrogen and sulfur co-doped graphene supported MoS 2 (MoS 2 /NS-G) nanosheets were prepared through a one-pot thermal annealing method. The as prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectra and electrochemical techniques. The MoS 2 /NS-G shows high reversible capacity about 1200 mAh/g at current density of 150 mA/g and excellent stability in Li-ion batteries. It was demonstrated the co-doping of graphene by N and S could significantly enhance the durability of MoS 2 as anode materials for Li-ion batteries

Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Shpotyuk, O. [Pedagogical University, Czestochowa (Poland)]|[Institute of Materials, Lvov (Ukraine)

1997-12-31

The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author). 16 refs, 1 tab.

Chemical physics of decomposition of energetic materials. Problems and prospects

International Nuclear Information System (INIS)

Smirnov, Lev P

2004-01-01

The review is concerned with analysis of the results obtained in the kinetic and mechanistic studies on decomposition of energetic materials (explosives, powders and solid propellants). It is shown that the state-of-the art in this field is inadequate to the potential of modern chemical kinetics and chemical physics. Unsolved problems are outlined and ways of their solution are proposed.

Multiphase Combustion of Metalized Nanocomposite Energetic Materials

Science.gov (United States)

2014-12-19

on thermal conductivity and absorption coefficient for consolidated aluminum nanoparticles, International Journal of Heat and Mass Transfer, (06...28. Stacy, S.C., Zhang, X., Pantoya, M.L., Weeks, B., Effect of Density on Thermal Conductivity and Absorption Coefficient for Consolidated Aluminum...energetic powder to ESD stimuli generated from a piezo electric crystal ( PZT ). Results show that a high PZT dielectric strength leads to faster

Nitrogen-rich salts of 5,5‧-bistetrazole-1,1‧-diolate: Syntheses, structures and properties

Science.gov (United States)

Yang, Ting; Zhang, Jian-Guo; Zhang, Zhi-Bin; Gozin, Michael

2018-03-01

A series of new nitrogen-rich energetic salts containing 1H,1‧H-[5,5‧-bitetrazole]-1,1‧-diol (BTO) anion and ethane-1,2-diaminium (1), 1-amino-1H-1,2,3-triazol-3-ium (2), 4-amino-4H-1,2,4-triazol-1-ium (3) and 4,5-diamino-4H-1,2,4-triazol-1-ium (4) cations were synthesized by direct salt formation or by metathesis strategy. The structures of energetic salts 1-4 were comprehensively characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopies and by X-ray crystallography. DSC and TGA methods were used to study thermal properties of these salts. Additionally, the non-isothermal kinetic parameters and thermodynamic parameters were calculated by utilizing the Kissinger's and Ozawa-Doyle's methods. The enthalpies of formation for all target compounds in this study were calculated, and their sensitivity to mechanical impact and friction was tested according to BAM guidelines. We found these new energetic salts exhibit good thermal stability and have typical decomposition temperatures above 230 °C, except for the salt 2. All our salts have highly-positive enthalpies of formation (311.1-473.6 kJ mol-1) and are insensitive to impact and friction stimuli (>40 J, 120 N). With a high nitrogen-rich content, high enthalpy of formation, good thermostability and very low sensitivity to impact, some of these new salts may have a potential for application in the field of environmentally friendly insensitive energetic materials.

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...

Surface Thermometry of Energetic Materials by Laser-Induced Fluorescence

Science.gov (United States)

1989-09-01

at 34 yttrium- aluminum -garnet (Dy:YAG). The simplified energy diagram of Dy:YAG is shown in Fig. 1. Absorbed laser light (at 355 nrm) can 5 excite the...the thermometric technique on a surface similar to that of an energetic material, a thermal-setting plastic supplied by Buehler, Ltd., was employed...temperature over the temperature range of interest. The rare-earth ion dysprosium (Dy) doped into a yttrium- aluminum -garnet (YAG) crystal was I determined

Three-dimensional simulations of void collapse in energetic materials

Science.gov (United States)

Rai, Nirmal Kumar; Udaykumar, H. S.

2018-03-01

The collapse of voids in porous energetic materials leads to hot-spot formation and reaction initiation. This work advances the current knowledge of the dynamics of void collapse and hot-spot formation using 3D reactive void collapse simulations in HMX. Four different void shapes, i.e., sphere, cylinder, plate, and ellipsoid, are studied. For all four shapes, collapse generates complex three-dimensional (3D) baroclinic vortical structures. The hot spots are collocated with regions of intense vorticity. The differences in the vortical structures for the different void shapes are shown to significantly impact the relative sensitivity of the voids. Voids of high surface area generate hot spots of greater intensity; intricate, highly contorted vortical structures lead to hot spots of corresponding tortuosity and therefore enhanced growth rates of reaction fronts. In addition, all 3D voids are shown to be more sensitive than their two-dimensional (2D) counterparts. The results provide physical insights into hot-spot formation and growth and point to the limitations of 2D analyses of hot-spot formation.

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.

Simulation of Metal Particulates in High Energetic Materials

Science.gov (United States)

2015-05-28

temperatures and pressures disintegrate the carbon- fiber casing, thus not producing any fragments. These carbon-fiber casing warheads are a solution...Polymer-Bonded Explosive (PBX) and Livermore’s High-Energy Explosive (LX) are examples of ex- plosives that use “ plastic ” as a binder material. Other...simulation data to empirical data does not provide any benefit to this research due to the complexity of plastically bonded explosives like PBX9501. The

High-Density Energetic Metal–Organic Frameworks Based on the 5,5′-Dinitro-2H,2′H-3,3′-bi-1,2,4-triazole

Directory of Open Access Journals (Sweden)

Yalu Dong

2017-06-01

Full Text Available High-energy metal–organic frameworks (MOFs based on nitrogen-rich ligands are an emerging class of explosives, and density is one of the positive factors that can influence the performance of energetic materials. Thus, it is important to design and synthesize high-density energetic MOFs. In the present work, hydrothermal reactions of Cu(II with the rigid polynitro heterocyclic ligands 5,5′-dinitro-2H,2′H-3,3′-bi-1,2,4-triazole (DNBT and 5,5′-dinitro-3,3′-bis-1,2,4-triazole-1-diol (DNBTO gave two high-density MOFs: [Cu(DNBT(ATRZ3]n (1 and [Cu(DNBTO(ATRZ2(H2O2]n (2, where ATRZ represents 4,4′-azo-1,2,4-triazole. The structures were characterized by infrared spectroscopy, elemental analysis, ultraviolet-visible (UV absorption spectroscopy and single-crystal X-ray diffraction. Their thermal stabilities were also determined by thermogravimetric/differential scanning calorimetry analysis (TG/DSC. The results revealed that complex 1 has a two-dimensional porous framework that possesses the most stable chair conformations (like cyclohexane, whereas complex 2 has a one-dimensional polymeric structure. Compared with previously reported MOFs based on copper ions, the complexes have higher density (ρ = 1.93 g cm−3 for complex 1 and ρ = 1.96 g cm−3 for complex 2 and high thermal stability (decomposition temperatures of 323 °C for complex 1 and 333.3 °C for complex 2, especially because of the introduction of an N–O bond in complex 2. We anticipate that these two complexes would be potential high-energy density materials.

Nitrogen-Doped Carbon for Red Phosphorous Based Anode Materials for Lithium Ion Batteries

Directory of Open Access Journals (Sweden)

Jiaoyang Li

2018-01-01

Full Text Available Serving as conductive matrix and stress buffer, the carbon matrix plays a pivotal role in enabling red phosphorus to be a promising anode material for high capacity lithium ion batteries and sodium ion batteries. In this paper, nitrogen-doping is proved to effective enhance the interface interaction between carbon and red phosphorus. In detail, the adsorption energy between phosphorus atoms and oxygen-containing functional groups on the carbon is significantly reduced by nitrogen doping, as verified by X-ray photoelectron spectroscopy. The adsorption mechanisms are further revealed on the basis of DFT (the first density functional theory calculations. The RPNC (red phosphorus/nitrogen-doped carbon composite material shows higher cycling stability and higher capacity than that of RPC (red phosphorus/carbon composite anode. After 100 cycles, the RPNC still keeps discharge capacity of 1453 mAh g−1 at the current density of 300 mA g−1 (the discharge capacity of RPC after 100 cycles is 1348 mAh g−1. Even at 1200 mA g−1, the RPNC composite still delivers a capacity of 1178 mAh g−1. This work provides insight information about the interface interactions between composite materials, as well as new technology develops high performance phosphorus based anode materials.

Bacterial-cellulose-derived carbon nanofiber@MnO₂ and nitrogen-doped carbon nanofiber electrode materials: an asymmetric supercapacitor with high energy and power density.

Science.gov (United States)

Chen, Li-Feng; Huang, Zhi-Hong; Liang, Hai-Wei; Guan, Qing-Fang; Yu, Shu-Hong

2013-09-14

A new kind of high-performance asymmetric supercapacitor is designed with pyrolyzed bacterial cellulose (p-BC)-coated MnO₂ as a positive electrode material and nitrogen-doped p-BC as a negative electrode material via an easy, efficient, large-scale, and green fabrication approach. The optimal asymmetric device possesses an excellent supercapacitive behavior with quite high energy and power density. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of a new energetic nitrate ester

Energy Technology Data Exchange (ETDEWEB)

Chavez, David E [Los Alamos National Laboratory

2008-01-01

Nitrate esters have been known as useful energetic materials since the discovery of nitroglycerin by Ascanio Sobrero in 1846. The development of methods to increase the safety and utility of nitroglycerin by Alfred Nobel led to the revolutionary improvement in the utility of nitroglycerin in explosive applications in the form of dynamite. Since then, many nitrate esters have been prepared and incorporated into military applications such as double-based propellants, detonators and as energetic plasticizers. Nitrate esters have also been shown to have vasodilatory effects in humans and thus have been studied and used for treatments of ailments such as angina. The mechanism of the biological response towards nitrate esters has been elucidated recently. Interestingly, many of the nitrate esters used for military purposes are liquids (ethylene glycol dinitrate, propylene glycol dinitrate, etc). Pentaerythritol tetranitrate (PETN) is one of the only solid nitrate esters, besides nitrocellulose, that is used in any application. Unfortunately, PETN melting point is above 100 {sup o}C, and thus must be pressed as a solid for detonator applications. A more practical material would be a melt-castable explosive, for potential simplification of manufacturing processes. Herein we describe the synthesis of a new energetic nitrate ester (1) that is a solid at ambient temperatures, has a melting point of 85-86 {sup o}C and has the highest density of any known nitrate ester composed only of carbon, hydrogen, nitrogen and oxygen. We also describe the chemical, thermal and sensitivity properties of 1 as well as some preliminary explosive performance data.

Synthesis of nitrogen-doped porous carbon nanofibers as an efficient electrode material for supercapacitors.

Science.gov (United States)

Chen, Li-Feng; Zhang, Xu-Dong; Liang, Hai-Wei; Kong, Mingguang; Guan, Qing-Fang; Chen, Ping; Wu, Zhen-Yu; Yu, Shu-Hong

2012-08-28

Supercapacitors (also known as ultracapacitors) are considered to be the most promising approach to meet the pressing requirements of energy storage. Supercapacitive electrode materials, which are closely related to the high-efficiency storage of energy, have provoked more interest. Herein, we present a high-capacity supercapacitor material based on the nitrogen-doped porous carbon nanofibers synthesized by carbonization of macroscopic-scale carbonaceous nanofibers (CNFs) coated with polypyrrole (CNFs@polypyrrole) at an appropriate temperature. The composite nanofibers exhibit a reversible specific capacitance of 202.0 F g(-1) at the current density of 1.0 A g(-1) in 6.0 mol L(-1) aqueous KOH electrolyte, meanwhile maintaining a high-class capacitance retention capability and a maximum power density of 89.57 kW kg(-1). This kind of nitrogen-doped carbon nanofiber represents an alternative promising candidate for an efficient electrode material for supercapacitors.

GAP pre-polymer, as an energetic binder and high performance additive for propellants and explosives: A review

Directory of Open Access Journals (Sweden)

Mehmet S. Eroglu

2017-08-01

Full Text Available In preparation of energetic composite formulations, functionally terminated pre-polymers have been used as binder. After physically mixing the pre-polymers with oxidizing components, metallic fuel, burning rate modifier and other minor ingredients, they are cured with a suitable curing agent to provide physical and chemical stability. These pre-polymers could be functionalized with carboxyl, epoxide or hydroxyl groups at varying average chain functionalities. For carboxyl-terminated pre-polymers, an epoxy functional curing agents could be used. If the pre-polymer possesses hydroxyl groups, isocyanate functional curing agents are the most suitable curing agents in terms of easy and efficient processing. Glycidyl azide polymer (GAP is one of the well-known low-molecular weight energetic liquid pre-polymer, which was developed to use as energetic binder, high performance additive and gas generator for high performance smokeless composite propellant and explosive formulations. Linear or branched GAP can be synthesized by nucleophilic substitution reaction of corresponding poly(epichlorohydrin (PECH with sodium azide through replacement of chloromethyl groups of PECH with pendant energetic azido-methyl groups on the polyether main chain. Positive heat of formation (+957 kJ/kg enables exothermic and rapid decomposition of GAP producing fuel rich gases. Its polyether main chain provides GAP with relatively low glass transition temperature (Tg= - 48 oC and presence of hydroxyl functional groups allows it to have easy processing in curing with isocyanate curing agents to form covalently crosslinked polyurethane structure. These outstanding properties of GAP enable it to be used as energetic polymeric binder and high performance additive in preparation of energetic materials and low vulnerable explosives.

Evaluation of Joint Performance on High Nitrogen Stainless Steel Which is Expected to Have Higher Allergy Resistance

Science.gov (United States)

Nakano, Kouichi

Austenitic stainless steel, which includes nickel for stabilizing austenitic structure, is used for various purposes, for example, for structural material, corrosion-resistant material, biomaterial etc. Nickel is set as one of the rare metals and economizing on nickel as the natural resources is required. On the other hand, nickel is one of the metals that cause metallic allergy frequently. Therefore, high nitrogen stainless steel, where nitrogen stabilizes austenitic structure instead of nickel, has been developed in Japan and some of the foreign countries for the above reason. When high nitrogen stainless steel is fused and bonded, dissolved nitrogen is released to the atmospheric area, and some of the material properties will change. In this study, we bonded high nitrogen stainless steel by stud welding process, which is able to bond at short time, and we evaluate joint performance. We have got some interesting results from the other tests and examinations.

Structural and magnetocaloric properties of (Mn,Fe){sub 2}(P,Si) materials with added nitrogen

Energy Technology Data Exchange (ETDEWEB)

Thang, N.V., E-mail: v.t.nguyen-1@tudelft.nl; Miao, X.F., E-mail: X.F.Miao@tudelft.nl; Dijk, N.H. van, E-mail: N.H.vanDijk@tudelft.nl; Brück, E., E-mail: E.H.Bruck@tudelft.nl

2016-06-15

Amongst magnetic materials that exhibit a giant magnetocaloric effect near room temperature, the (Mn,Fe){sub 2}(P,Si) system is one of the most promising candidates for magnetic refrigeration. Although the (Mn,Fe){sub 2}(P,Si) materials hold many advantages, controlling the magnetic entropy change ΔS{sub m}, the adiabatic temperature change ΔT{sub ad}, the thermal hysteresis and the mechanical stability across the ferromagnetic transition requires a delicate tuning of the composition. This work investigates the addition of nitrogen, as an interstitial or substitutional element, as a new parameter to tune the properties of (Mn,Fe){sub 2}(P,Si) materials. We found that the nitrogen addition results in a decrease of the Curie temperature, consistent with the observed increase in the c/a ratio. The introduction of nitrogen in (Mn,Fe){sub 2}(P,Si) materials also results in a strong enhancement of the mechanical stability. - Highlights: • N-doped materials were synthesized by high-energy ball milling and solid-state reactions. • Nitrogen atoms enter the structure both as substitutional and as interstitial element in (Mn,Fe){sub 2}(P,Si) materials. • Nitrogen addition leads to a decrease in the Curie temperature, while improving the mechanical stability and preserving the magnetocaloric properties. • The origin of the increase in the thermal hysteresis by increasing the N content has been investigated by analyzing the XRD data.

High temperature material characterization and advanced materials development

International Nuclear Information System (INIS)

Ryu, Woo Seog; Kim, D. H.; Kim, S. H. and others

2005-03-01

The study is to characterize the structural materials under the high temperature, one of the most significant environmental factors in nuclear systems. And advanced materials are developed for high temperature and/or low activation in neutron irradiation. Tensile, fatigue and creep properties have been carried out at high temperature to evaluate the mechanical degradation. Irradiation tests were performed using the HANARO. The optimum chemical composition and heat treatment condition were determined for nuclear grade 316NG stainless steel. Nitrogen, aluminum, and tungsten were added for increasing the creep rupture strength of FMS steel. The new heat treatment method was developed to form more stable precipitates. By applying the novel whiskering process, high density SiC/SiC composites with relative density above 90% could be obtained even in a shorter processing time than the conventional CVI process. Material integrated databases are established using data sheets. The databases of 6 kinds of material properties are accessible through the home page of KAERI material division

Hierarchically porous silicon–carbon–nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes

Science.gov (United States)

Meng, Lala; Zhang, Xiaofei; Tang, Yusheng; Su, Kehe; Kong, Jie

2015-01-01

The hierarchically macro/micro-porous silicon–carbon–nitrogen (Si–C–N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp2-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg·g−1 and 1084.5 mg·g−1 for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si–C–N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants. PMID:25604334

The HZE radiation problem. [highly-charged energetic galactic cosmic rays

Science.gov (United States)

Schimmerling, Walter

1990-01-01

Radiation-exposure limits have yet to be established for missions envisioned in the framework of the Space Exploration Initiative. The radiation threat outside the earth's magnetosphere encompasses protons from solar particle events and the highly charged energetic particles constituting galactic cosmic rays; radiation biology entails careful consideration of the extremely nonuniform patterns of such particles' energy deposition. The ability to project such biological consequences of exposure to energetic particles as carcinogenicity currently involves great uncertainties from: (1) different regions of space; (2) the effects of spacecraft structures; and (3) the dose-effect relationships of single traversals of energetic particles.

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

International Nuclear Information System (INIS)

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

2005-01-01

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 6 mm±0.4 mm exists below which ignition by CO 2 laser is not possible at the tested irradiances of 29 W/cm 2 and 38 W/cm 2 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

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.

Energetic evaluation of indigenous tree and shrub species in Basilicata, Southern Italy

Directory of Open Access Journals (Sweden)

Todaro L

2007-01-01

Full Text Available An evaluation of energetic characteristics such as high calorific value (on ash-free dry weight basis, ash, carbon, nitrogen, and moisture content of 12 indigenous tree and shrub species of Southern Italy (Basilicata Region was carried out. The studied species are the most abundant in this area: Quercus cerris L., Quercus pubescens Willd., Fraxinus ornus L., Populus canescens (Aiton Smith, Salix alba L., Alnus cordata L., Robinia pseudoacacia L., Olea europaea L., Spartium junceum L., Rubus hirtus W., Onopordum illirium L., Arundo donax L. For Q. cerris, Q. pubescens and O. europaea L., the energetic characteristics were measured by separating the wood components from the leaves. Q. cerris leaves contained the greatest high calorific value. F. ornus leaves had a greater ash content than the other samples while the lowest values were measured for S. junceum, Q. pubescens and R. pseudoacacia. The highest content of Carbon was in O. europaea leaves. A. donax and O. illirium had the lower level of high calorific value and Carbon than all the other species. The highest Nitrogen content was measured in Q. cerris leaves and the lowest one in F. ornus wood components.

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.

Nitrogen-rich heterocycles as reactivity retardants in shocked insensitive explosives.

Science.gov (United States)

Manaa, M Riad; Reed, Evan J; Fried, Laurence E; Goldman, Nir

2009-04-22

We report the first quantum-based multiscale simulations to study the reactivity of shocked perfect crystals of the insensitive energetic material triaminotrinitrobenzene (TATB). Tracking chemical transformations of TATB experiencing overdriven shock speeds of 9 km/s for up to 0.43 ns and 10 km/s for up to 0.2 ns reveal high concentrations of nitrogen-rich heterocyclic clusters. Further reactivity of TATB toward the final decomposition products of fluid N(2) and solid carbon is inhibited due to the formation of these heterocycles. Our results thus suggest a new mechanism for carbon-rich explosive materials that precedes the slow diffusion-limited process of forming the bulk solid from carbon clusters and provide fundamental insight at the atomistic level into the long reaction zone of shocked TATB.

Papers of 4. Scientific-Technical Seminar: Material Study for Electric Power Stations and Energetics

International Nuclear Information System (INIS)

1997-01-01

The research on the materials commonly used in electric power stations and energetics have been summarized in the course of the seminar. Especially a different kinds of steels have been investigated from the view point of their desirable mechanical and corrosion properties

A Coupled Damage and Reaction Model for Simulating Energetic Material Response to Impact Hazards

International Nuclear Information System (INIS)

BAER, MELVIN R.; DRUMHELLER, D.S.; MATHESON, E.R.

1999-01-01

The Baer-Nunziato multiphase reactive theory for a granulated bed of energetic material is extended to allow for dynamic damage processes, that generate new surfaces as well as porosity. The Second Law of Thermodynamics is employed to constrain the constitutive forms of the mass, momentum, and energy exchange functions as well as those for the mechanical damage model ensuring that the models will be dissipative. The focus here is on the constitutive forms of the exchange functions. The mechanical constitutive modeling is discussed in a companion paper. The mechanical damage model provides dynamic surface area and porosity information needed by the exchange functions to compute combustion rates and interphase momentum and energy exchange rates. The models are implemented in the CTH shock physics code and used to simulate delayed detonations due to impacts in a bed of granulated energetic material and an undamaged cylindrical sample

High capacity and high rate capability of nitrogen-doped porous hollow carbon spheres for capacitive deionization

International Nuclear Information System (INIS)

Zhao, Shanshan; Yan, Tingting; Wang, Hui; Chen, Guorong; Huang, Lei; Zhang, Jianping; Shi, Liyi; Zhang, Dengsong

2016-01-01

Graphical abstract: - Highlights: • The nitrogen-doped porous hollow carbon spheres were prepared. • The obtained materials have a good capacitive deionization performance. • The electrodes show high salt adsorption rate and good regeneration performance. - Abstract: In this work, nitrogen-doped porous hollow carbon spheres (N-PHCS) were well prepared by using polystyrene (PS) spheres as hard templates and dopamine hydrochloride as carbon and nitrogen sources. Field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images demonstrate that the N-PHCS have a uniform, spherical and hollow structure. Nitrogen adsorption–desorption analysis shows that the N-PHCS have a high specific area of 512 m 2 /g. X-ray photoelectron spectroscopy result reveals that the nitrogen doping amount is 2.92%. The hollow and porous structure and effective nitrogen doping can contribute to large accessible surface area, efficient ion transport and good conductivity. In the electrochemical tests, we can conclude that the N-PHCS have a high specific capacitance value, a good stability and low inner resistance. The N-PHCS electrodes present a high salt adsorption capacity of 12.95 mg/g at a cell voltage of 1.4 V with a flow rate of 40 mL/min in a 500 mg/L NaCl aqueous solution. Moreover, the N-PHCS electrodes show high salt adsorption rate and good regeneration performance in the CDI process. With high surface specific area and effective nitrogen doping, the N-PHCS is promising to the CDI and other electrochemical applications.

High capacity and high rate capability of nitrogen-doped porous hollow carbon spheres for capacitive deionization

Energy Technology Data Exchange (ETDEWEB)

Zhao, Shanshan; Yan, Tingting; Wang, Hui; Chen, Guorong; Huang, Lei; Zhang, Jianping; Shi, Liyi; Zhang, Dengsong, E-mail: dszhang@shu.edu.cn

2016-04-30

Graphical abstract: - Highlights: • The nitrogen-doped porous hollow carbon spheres were prepared. • The obtained materials have a good capacitive deionization performance. • The electrodes show high salt adsorption rate and good regeneration performance. - Abstract: In this work, nitrogen-doped porous hollow carbon spheres (N-PHCS) were well prepared by using polystyrene (PS) spheres as hard templates and dopamine hydrochloride as carbon and nitrogen sources. Field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images demonstrate that the N-PHCS have a uniform, spherical and hollow structure. Nitrogen adsorption–desorption analysis shows that the N-PHCS have a high specific area of 512 m{sup 2}/g. X-ray photoelectron spectroscopy result reveals that the nitrogen doping amount is 2.92%. The hollow and porous structure and effective nitrogen doping can contribute to large accessible surface area, efficient ion transport and good conductivity. In the electrochemical tests, we can conclude that the N-PHCS have a high specific capacitance value, a good stability and low inner resistance. The N-PHCS electrodes present a high salt adsorption capacity of 12.95 mg/g at a cell voltage of 1.4 V with a flow rate of 40 mL/min in a 500 mg/L NaCl aqueous solution. Moreover, the N-PHCS electrodes show high salt adsorption rate and good regeneration performance in the CDI process. With high surface specific area and effective nitrogen doping, the N-PHCS is promising to the CDI and other electrochemical applications.

Energetic utilization of dietary fiber in pigs

NARCIS (Netherlands)

Rijnen, M.M.J.A.

2003-01-01

The energetic utilization of fermentable dietary fiber (fDF) of different fiber sources and its relation to physical activity and housing conditions was studied in three experiments. In all experiments the daily intake of digestible nutrients, nitrogen and energy balances, heat production, and

Nitrogen doped activated carbon from pea skin for high performance supercapacitor

Science.gov (United States)

Ahmed, Sultan; Ahmed, Ahsan; Rafat, M.

2018-04-01

In this work, nitrogen doped porous carbon (NDC) has been synthesized employing a facile two-step process. Firstly, carbon precursor (pea skin) was heated with melamine (acting as nitrogen source) followed by activation with KOH in different ratios. The dependence of porosity and nitrogen content on impregnation ratio was extensively studied. Other textural properties of prepared NDC sample were studied using standard techniques of material characterization. The electrochemical performance of NDC sample as an electrode was studied in two-electrode symmetric supercapacitor system. 1 M LiTFSI (lithium bis-trifluoromethanesulfonimide) solution in IL EMITFSI (1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), was used as electrolyte. It was found that the fabricated supercapacitor cell offers high values of specific capacitance (141.1 F g‑1), specific energy (19.6 Wh kg‑1) and specific power (25.4 kW kg‑1) at current density of 1.3 A g‑1. More importantly, the fabricated supercapacitor cell shows capacitance retention of ∼75%, for more than 5000 cycles. The enhanced performance of NDC sample is primarily due to large surface area with favorable surface structure (contributing to double layer capacitance) and presence of nitrogen functionalities (contributing to pseudo-capacitance). Such important features make the synthesized NDC sample, an attractive choice for electrode material in high performance supercapacitor.

Reaction path of energetic materials using THOR code

Science.gov (United States)

Durães, L.; Campos, J.; Portugal, A.

1998-07-01

The method of predicting reaction path, using THOR code, allows for isobar and isochor adiabatic combustion and CJ detonation regimes, the calculation of the composition and thermodynamic properties of reaction products of energetic materials. THOR code assumes the thermodynamic equilibria of all possible products, for the minimum Gibbs free energy, using HL EoS. The code allows the possibility of estimating various sets of reaction products, obtained successively by the decomposition of the original reacting compound, as a function of the released energy. Two case studies of thermal decomposition procedure were selected, calculated and discussed—pure Ammonium Nitrate and its based explosive ANFO, and Nitromethane—because their equivalence ratio is respectively lower, near and greater than the stoicheiometry. Predictions of reaction path are in good correlation with experimental values, proving the validity of proposed method.

Antimony Anchored with Nitrogen-Doping Porous Carbon as a High-Performance Anode Material for Na-Ion Batteries.

Science.gov (United States)

Wu, Tianjing; Hou, Hongshuai; Zhang, Chenyang; Ge, Peng; Huang, Zhaodong; Jing, Mingjun; Qiu, Xiaoqing; Ji, Xiaobo

2017-08-09

Antimony represents a class of unique functional materials in sodium-ion batteries with high theoretical capacity (660 mA h g -1 ). The utilization of carbonaceous materials as a buffer layer has been considered an effective approach to alleviate rapid capacity fading. Herein, the antimony/nitrogen-doping porous carbon (Sb/NPC) composite with polyaniline nanosheets as a carbon source has been successfully achieved. In addition, our strategy involves three processes, a tunable organic polyreaction, a thermal annealing process, and a cost-effective reduction reaction. The as-prepared Sb/NPC electrode demonstrates a great reversible capacity of 529.6 mA h g -1 and an outstanding cycling stability with 97.2% capacity retention after 100 cycles at 100 mA g -1 . Even at 1600 mA g -1 , a superior rate capacity of 357 mA h g -1 can be retained. Those remarkable electrochemical performances can be ascribed to the introduction of a hierarchical porous NPC material to which tiny Sb nanoparticles of about 30 nm were well-wrapped to buffer volume expansion and improve conductivity.

The problems of high-nitrogen steels production

International Nuclear Information System (INIS)

Svyazhin, A.G.; Kaputkina, L.M.; Efimenko, S.P.

1999-01-01

Analysis of existing technologies of high-nitrogen steel production shows that rational nitrogen content in mass production corresponds to moderate high values. Such steels can be smelted under normal or slightly elevated pressure in steelmaking units, using processes of mass- and special metallurgy. High-nitrogen steels with ''overequilibrium'' nitrogen content are promising, but technology and equipment for production of them are complicated, and production of such steels is therefore limited. (orig.)

Trapping and re-emission of energetic hydrogen and helium ions in materials

International Nuclear Information System (INIS)

Yamaguchi, Sadae

1981-01-01

The experimental results on the trapping and re-emission of energetic hydrogen and helium ions in materials are explained. The trapping of deuterium and helium in graphite saturates at the concentration of 10 18 ions/cm 2 . The trapping rate of hydrogen depends on the kinds of target materials. In the case of the implantation in Mo over 3 x 10 16 H/cm 2 , hydrogen is hardly trapped. On the other hand, the trapping of hydrogen in Ti, Zr and Ta which form solid solution is easily made. The hydrogen in these metals can diffuse toward the inside of metals. The deuterium retained in 316 SS decreased with time. The trapping rate reached saturation more rapidly at higher implantation temperature. The effective diffusion constant for the explanation of the re-emission process is 1/100 as small as the ordinary value. The radiation damage due to helium irradiation affects on the trapping of deuterium in Mo. The temperature dependence of the trapping rate can be explained by the diffusion model based on the Sievert's law. The re-emission of helium was measured at various temperature. At low temperature, the re-emission was low at first, then the rate increased. At high temperature, the re-emission rate was high from the beginning. (Kato, T.)

Study on penetration-induced initiation of energetic fragment

Science.gov (United States)

Qiao, Xiangxin; Xu, Heyang

2017-09-01

In order to investigate penetration-induced initiation of energetic fragment penetrating target, PTFE/Al (mass ratio 73.5/26.5) pressed and sintered into a Ф8mm × 8mm cylinder. To form energetic fragment, the cylinder was put into a closed container made by 35CrMnSiA. The container is 12mm long, 2mm thick. Energetic fragments were launched by a 14.5mm ballistic gun with a series of velocities and the penetrate process was simulated by AUTODYN-3D. The results show that the stress peak of energetic material exceed the initiation threshold, and energetic material will deflagrate, when energetic fragments impact velocity more than 800 m/s. The research results can provide reference for designs of energetic warhead.

Real time in-situ sensing of damage evolution in nanocomposite bonded surrogate energetic materials

Science.gov (United States)

Sengezer, Engin C.; Seidel, Gary D.

2016-04-01

The current work aims to explore the potential for in-situ structural health monitoring in polymer bonded energetic materials through the introduction of carbon nanotubes (CNTs) into the binder phase as a means to establish a significant piezoresistive response through the resulting nanocomposite binder. The experimental effort herein is focused towards electro-mechanical characterization of surrogate materials in place of actual energetic (explosive) materials in order to provide proof of concept for the strain and damage sensing. The electrical conductivity and the piezoresistive behavior of samples containing randomly oriented MWCNTs introduced into the epoxy (EPON 862) binder of 70 wt% ammonium perchlorate-epoxy hybrid composites are quantitatively and qualitatively evaluated. Brittle failure going through linear elastic behavior, formation of microcracks leading to reduction in composite load carrying capacity and finally macrocracks resulting in eventual failure are observed in the mechanical response of MWNT-ammonium perchlorateepoxy hybrid composites. Incorporating MWNTs into local polymer binder improves the effective stiffness about 40% compared to neat ammonium perchlorate-polymer samples. The real time in-situ relative change in resistance for MWNT hybrid composites was detected with the applied strains through piezoresistive response.

Proceedings of the eleventh international conference on high nitrogen steels and interstitial alloys: souvenir

International Nuclear Information System (INIS)

2012-01-01

Stainless steels serve a multitude of applications from brightly polished consumer products to machinery and equipment for challenging industrial environments. Improvements of mechanical and corrosion properties of stainless steels and a whole spectrum of steels for high pressure and high temperature applications, necessitated development of new elegant class of High Nitrogen Steels (HNS). Presently high nitrogen steels occupy a centre stage in many strategic industries like power, oil and gas and infrastructure etc. In nuclear industry, in the demanding environments of fuel reprocessing and waste managing plants HNS can find possible applications. Already nitrogen alloyed stainless steel has found its niche as structural material of Fast Breeder Reactors and Advanced Heavy Water Reactor in India. Nitrogen is also an important alloying element in the new generation ferritic steels meant for high temperature applications. Papers relevant to INIS are indexed separately

High-capacitance supercapacitors using nitrogen-decorated porous carbon derived from novolac resin containing peptide linkage

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Jung [Institute of Carbon Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Jang, In Young; Park, Ki Chul; Jung, Yong Chae; Oka, Takuyuki [Department of Electric and Electronic Engineering, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Iinou, Satoshi [MEFS, Co. Ltd. Choei Nagano, Higasiguchi Bldg, 2F, 1000-1 Gentakubo, Kurita, Nagano 380-0921 (Japan); Komori, Yasuhiro; Kozutsumi, Toshihiko; Hashiba, Takashi [SHOWA HIGHPOLYMER, Co., Ltd. 1021 Tomizuka-cho, Isesaki-City, Gunma 372-0833 (Japan); Kim, Yoong Ahm, E-mail: yak@endomoribu.shinshu-u.ac.j [Department of Electric and Electronic Engineering, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Endo, Morinobu [Institute of Carbon Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan)] [Department of Electric and Electronic Engineering, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan)

2010-08-01

We fabricated nitrogen-decorated porous carbon exhibiting high capacitance per unit volume and unit weight via chemical activation of novolac resin containing peptide linkage. The porosity and the amount of nitrogen atoms were controlled by changing the molecular weight of novolac resin, the added amount of potassium hydroxide, or both. After chemical activation, positively charged nitrogen atoms (i.e., pyridine/pyrrole) at 400.3 eV in photoemission spectra contributed to both a shift in the point of zero charge toward negative potential and the generation of pseudocapacitance. Suitably developed pores and the positively charged nitrogen atoms make nitrogen-decorated novolac resin-derived porous carbon a promising material for electrodes in high-performance supercapacitors.

Coating and Characterization of Mock and Explosive Materials

Directory of Open Access Journals (Sweden)

Emily M. Hunt

2012-01-01

Full Text Available This project develops a method of manufacturing plastic-bonded explosives by using use precision control of agglomeration and coating of energetic powders. The energetic material coating process entails suspending either wet or dry energetic powders in a stream of inert gas and contacting the energetic powder with atomized droplets of a lacquer composed of binder and organic solvent. By using a high-velocity air stream to pneumatically convey the energetic powders and droplets of lacquer, the energetic powders are efficiently wetted while agglomerate drying begins almost immediately. The result is an energetic powder uniformly coated with binder, that is, a PBX, with a high bulk density suitable for pressing. Experiments have been conducted using mock explosive materials to examine coating effectiveness and density. Energetic materials are now being coated and will be tested both mechanically and thermally. This allows for a comprehensive comparison of the morphology and reactivity of the newly coated materials to previously manufactured materials.

Energetic Particles at High Latitudes of the Heliosphere

International Nuclear Information System (INIS)

Zhang Ming

2004-01-01

Ulysses has by now made two complete out-of-ecliptic orbits around the sun. The first encounter of the solar poles occurred in 1994-1995, when the sun was near the minimum of its activity cycle, while the second one was in 2000-2001, when the sun was at solar maximum. To our surprise, energetic particles of all origins at high latitude are not much different from those we observe near the ecliptic for at least these two phases of solar cycle. The latitude gradients of galactic and anomalous cosmic rays are positive but small at the 1994-1995 solar minimum and almost zero at the 2000-2001 solar maximum, while temporal solar cycle variation dominates their flux variation at all latitudes. Solar energetic particles from all large gradual events can be seen at both Ulysses and Earth no matter how large their spatial separations from the solar event are, and the particle flux often reaches a uniform level in the entire inner heliosphere within a few days after event onset and remains so throughout the decay phase that can sometimes last over a month. Energetic particles accelerated by low-latitude CIRs can appear at high latitudes, far beyond the latitudinal range of CIRs. All these observations suggest that latitudinal transport of energetic particles is quite easy. In addition, because the average magnetic field is radial at the pole, The Ulysses observations indicate that parallel diffusion and drift in the radial direction need to be reduced at the poles relative to their equatorial values. To achieve such behaviors of particle transport, the heliospheric magnetic field needs a significant latitudinal component at the poles. A non-zero latitudinal magnetic field component can be produced by latitudinal motion of the magnetic field line in solar corona, which can be in form of either random walk suggested by Jokipii or large scale systematic motion suggested by Fisk

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

High frequency fishbone driven by passing energetic ions in tokamak plasmas

Science.gov (United States)

Wang, Feng; Yu, L. M.; Fu, G. Y.; Shen, Wei

2017-05-01

High frequency fishbone instability driven by passing energetic ions was first reported in the Princeton beta experiment with tangential neutral-beam-injection (Heidbrink et al 1986 Phys. Rev. Lett. 57 835-8). It could play an important role for ITER-like burning plasmas, where α particles are mostly passing particles. In this work, a generalized energetic ion distribution function and finite drift orbit width effect are considered to improve the theoretical model for passing particle driving fishbone instability. For purely passing energetic ions with zero drift orbit width, the kinetic energy δ {{W}k} is derived analytically. The derived analytic expression is more accurate as compared to the result of previous work (Wang 2001 Phys. Rev. Lett. 86 5286-8). For a generalized energetic ion distribution function, the fishbone dispersion relation is derived and is solved numerically. Numerical results show that broad and off-axis beam density profiles can significantly increase the beam ion beta threshold {βc} for instability and decrease mode frequency.

Data on trapping and re-emission of energetic hydrogen isotopes and helium in materials, supplement 1

International Nuclear Information System (INIS)

Yamaguchi, Sadae; Sugizaki, Yasuaki; Ozawa, Kunio; Nakai, Yohta.

1984-05-01

This is the supplement to the data on trapping and re-emission of energetic hydrogen isotopes and helium in materials (JAERI-M 82-118). It contains 32 data up to end of 1982, dividing it into following 6 sections: 1) Dose Dependence, 2) Target Material Dependence, 3) Target Temperature Dependence, 4) Incident Energy Dependence, 5) Damage Effects and 6) Ion-Induced Release. (author)

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

Science.gov (United States)

2009-12-31

materials. The initial work was focused on design and construction of an apparatus for injecting defects into the crystals using PZT ceramics ...in the energy partitioning (Table 2), which offers some insight into the nature of the energetic texture of crystalline materials not apparent in

Nitrogen Recovery by Fe-Ti Alloy from Molten Lithium at High Temperatures

International Nuclear Information System (INIS)

Juro Yagi; Akihiro Suzuki; Takayuki Terai; Takeo Muroga

2006-01-01

Molten lithium will be used as a beam target of IFMIF (International Fusion Materials Irradiation Facility), and is also expected as a self-cooling and tritium breeding material in fusion reactors. Since tritium is generated in both cases, tritium recovery is required from viewpoints of safety and a feasible fuel cycle. Nitrogen impurity in the lithium, however, not only enhance corrosion to tubing materials, but also promote nitride contamination on a surface of yttrium, which is considered to be a tritium gettering candidate. In our previous study, nitrogen recovery by hot trap method with Fe + 5%Ti alloy as a gettering material showed a higher nitrogen reduction capacity than that with Ti or Cr metal. In this study, high temperature recovery of nitrogen with Fe-Ti alloy was examined to achieve more efficient recovery and higher recovery rate coefficient. Fe - 4%Ti alloy are fabricated by electron beam melting, and its thin plates (40 mm x 10 mm x 1 mm) are used in our experiments. The Fe - 4%Ti alloy plates were immersed into 25 g of liquid lithium in Mo crucible under Ar atmosphere. The crucible was put in a SUS316 stainless steel pot heated at 600, 700, or 800 o C up to 100 hours. A small portion of the liquid lithium in the crucible was sampled out with adequate time interval, and the nitrogen concentrations in the sampled lithium were observed by changing nitrogen to ammonia. Experiments using lithium containing about 100 wt. ppm of nitrogen at the beginning show that the nitrogen reduction became faster with temperature and the minimum achieved nitrogen concentration was less than 20 wppm in case of 800 C. SEM-EDS analysis on the plates after experiment shows a Ti-rich surface layer of tens of micrometers on the alloy immersed in lithium at 800 C, and XPS analysis indicates the surface layer is TiN, while no Ti-rich layer nor TiN were observed on the alloys immersed at 600 o C and 700 o C. By increasing temperature from 600 o C to 800 o C, the diffusion

Three-Dimensional Nitrogen-Doped Hierarchical Porous Carbon as an Electrode for High-Performance Supercapacitors.

Science.gov (United States)

Tang, Jing; Wang, Tao; Salunkhe, Rahul R; Alshehri, Saad M; Malgras, Victor; Yamauchi, Yusuke

2015-11-23

A facile and sustainable procedure for the synthesis of nitrogen-doped hierarchical porous carbons with a three-dimensional interconnected framework (NHPC-3D) was developed. The strategy, based on a colloidal crystal-templating method, utilizes nitrogenous dopamine as the precursor due to its unique properties, including self-polymerization under mild alkaline conditions, coating onto various surfaces, a high carbonization yield, and well-preserved nitrogen doping after heat treatment. The obtained NHPC-3D possesses a high surface area of 1056 m(2)  g(-1) , a large pore volume of 2.56 cm(3)  g(-1) , and a high nitrogen content of 8.2 wt %. The NHPC-3D is implemented as the electrode material of a supercapacitor and exhibits a specific capacitance as high as 252 F g(-1) at a current density of 2 A g(-1) . The device also shows a high capacitance retention of 75.7 % at a higher current density of 20 A g(-1) in aqueous electrolyte due to a sufficient surface area for charge accommodation, reversible pseudocapacitance, and minimized ion-transport resistance, as a result of the advantageous interconnected hierarchical porous texture. These results showcase NHPC-3D as a promising candidate for electrode materials in supercapacitors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Characteristics of dry matter production and nitrogen accumulation in barley genotypes with high nitrogen utilization efficiency].

Science.gov (United States)

Huang, Yi; Li, Ting-Xuan; Zhang, Xi-Zhou; Ji, Lin

2014-07-01

A pot experiment was conducted under low (125 mg x kg-1) and normal (250 mg x kg(-1)) nitrogen treatments. The nitrogen uptake and utilization efficiency of 22 barley cultivars were investigated, and the characteristics of dry matter production and nitrogen accumulation in barley were analyzed. The results showed that nitrogen uptake and utilization efficiency were different for barley under two nitrogen levels. The maximal values of grain yield, nitrogen utilization efficiency for grain and nitrogen harvest index were 2.87, 2.91 and 2.47 times as those of the lowest under the low nitrogen treatment. Grain yield and nitrogen utilization efficiency for grain and nitrogen harvest index of barley genotype with high nitrogen utilization efficiency were significantly greater than low nitrogen utilization efficiency, and the parameters of high nitrogen utilization efficiency genotype were 82.1%, 61.5% and 50.5% higher than low nitrogen utilization efficiency genotype under the low nitrogen treatment. Dry matter mass and nitrogen utilization of high nitrogen utilization efficiency was significantly higher than those of low nitrogen utilization efficiency. A peak of dry matter mass of high nitrogen utilization efficiency occurred during jointing to heading stage, while that of nitrogen accumulation appeared before jointing. Under the low nitrogen treatment, dry matter mass of DH61 and DH121+ was 34.4% and 38.3%, and nitrogen accumulation was 54. 8% and 58.0% higher than DH80, respectively. Dry matter mass and nitrogen accumulation seriously affected yield before jointing stage, and the contribution rates were 47.9% and 54.7% respectively under the low nitrogen treatment. The effect of dry matter and nitrogen accumulation on nitrogen utilization efficiency for grain was the largest during heading to mature stages, followed by sowing to jointing stages, with the contribution rate being 29.5% and 48.7%, 29.0% and 15.8%, respectively. In conclusion, barley genotype with high

Time dependent design curves for a high nitrogen grade of 316LN stainless steel for fast reactor applications

Energy Technology Data Exchange (ETDEWEB)

Ganesh Kumar, J.; Ganesan, V.; Laha, K.; Mathew, M.D., E-mail: mathew@igcar.gov.in

2013-12-15

Highlights: • 316LN SS is an important high temperature structural material for sodium cooled fast reactors. • Creep strength of 316LN SS has been increased substantially by increasing the nitrogen content. • Creep design curves based on RCC-MR code procedures have been generated for this new material. • 100,000 h allowable stress at 600 °C increased by more than 40% as a result of doubling the nitrogen content in the steel. - Abstract: Type 316L(N) stainless steel (SS) containing 0.06–0.08 wt.% nitrogen is the major material for reactor assembly components of sodium cooled fast reactors (SFRs). With a view to increase the design life of SFRs to 60 years from the current life of 40 years, studies are being carried out to improve the high temperature creep and low cycle fatigue properties of 316LN SS by increasing the nitrogen content above 0.08 wt.%. In this investigation, the creep properties of a high nitrogen grade of 316LN SS containing 0.14 wt.% nitrogen have been studied. Creep tests were carried out at 550 °C, 600 °C and 650 °C at various stress levels in the range of 140–350 MPa. Creep strength was found to be significantly improved by doubling the nitrogen content in this steel. The maximum rupture life in these tests was 33,000 h. The creep data has been analyzed according to RCC-MR nuclear code procedures in order to generate the creep design curves for the high nitrogen grade of 316LN SS. Allowable stress for 100,000 h at 600 °C increased by more than 38% as a result of doubling the nitrogen content in the steel.

Highly nitrogen-doped carbon capsules: scalable preparation and high-performance applications in fuel cells and lithium ion batteries.

Science.gov (United States)

Hu, Chuangang; Xiao, Ying; Zhao, Yang; Chen, Nan; Zhang, Zhipan; Cao, Minhua; Qu, Liangti

2013-04-07

Highly nitrogen-doped carbon capsules (hN-CCs) have been successfully prepared by using inexpensive melamine and glyoxal as precursors via solvothermal reaction and carbonization. With a great promise for large scale production, the hN-CCs, having large surface area and high-level nitrogen content (N/C atomic ration of ca. 13%), possess superior crossover resistance, selective activity and catalytic stability towards oxygen reduction reaction for fuel cells in alkaline medium. As a new anode material in lithium-ion battery, hN-CCs also exhibit excellent cycle performance and high rate capacity with a reversible capacity of as high as 1046 mA h g(-1) at a current density of 50 mA g(-1) after 50 cycles. These features make the hN-CCs developed in this study promising as suitable substitutes for the expensive noble metal catalysts in the next generation alkaline fuel cells, and as advanced electrode materials in lithium-ion batteries.

Energetics Laboratory Facilities

Data.gov (United States)

Federal Laboratory Consortium — These energetic materials laboratories are equipped with explosion proof hoods with blow out walls for added safety, that are certified for safe handling of primary...

A new method for determining gas phase heat of formation of aromatic energetic compounds

Energy Technology Data Exchange (ETDEWEB)

Keshavarz, Mohammad H. [Department of Chemistry, Malek-ashtar University of Technology, Shahin-shahr P. O. Box 83145/115 (Iran); Tehrani, Masoud K. [Department of Physics, Malek-ashtar University of Technology, Shahin-shahr P. O. Box 83145/115 (Iran)

2007-04-15

A new correlation is introduced for desk calculation of gas phase heat of formation of aromatic energetic compounds that contain the elements of carbon, hydrogen, nitrogen and oxygen. Predicted gas phase heats of formation for 26 energetic compounds have a root mean square of deviation from experiment of 20.67 kJ/mol, which is in good agreement with respect to measured values of oxygen-lean and oxygen-rich aromatic energetic compounds. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Ignition and Reaction Analysis of High Loading Nano-Al/Fluoropolymer Energetic Composite Films

Science.gov (United States)

2014-01-01

A novel hybrid binder system for extrudable composite propellant,” International Journal of Energetic Materials and Chemical Propulsion, Vol. 11...Vol. 27, No. 5, 2002, pp. 262-266. 6 Wang, Y., Travas-Sejdic, J., Steiner, R., “Polymer gel electrolyte supported with microporous polyolefin

Mechanical properties of LMR structural materials at high temperature

International Nuclear Information System (INIS)

Kim, D. W.; Kuk, I. H.; Ryu, W. S. and others

1999-03-01

Austenitic stainless is used for the structural material of liquid metal reactor (LMR) because of good mechanical properties at high temperature. Stainless steel having more resistant to temperature by adding minor element has been developing for operating the LMR at higher temperature. Of many elements, nitrogen is a prospective element to modify type 316L(N) stainless steel because nitrogen is the most effective element for solid solution and because nitrogen retards the precipitation of carbide at grain boundary. Ti, Nb, and V are added to improve creep properties by stabilizing the carbides through forming MC carbide. Testing techniques of tensile, fatigue, creep, and creep-fatigue at high temperature are difficult. Moreover, testing times for creep and creep-fatigue tests are very long up to several tens of thousands hours because creep and creep-fatigue phenomena are time-dependent damage mechanism. So, it is hard to acquire the material data for designing LMR systems during a limited time. In addition, the integrity of LMR structural materials at the end of LMR life has to be predicted from the laboratory data tested during the short term because there is no data tested during 40 years. Therefore, the effect of elements on mechanical properties at high temperature was reviewed in this study and many methods to predict the long-term behaviors of structural materials by simulated modelling equation is shown in this report. (author). 32 refs., 9 tabs., 38 figs

Nitrogen-Doped Carbonaceous Materials for Removal of Phenol from Aqueous Solutions

Directory of Open Access Journals (Sweden)

Magdalena Hofman

2012-01-01

Full Text Available Carbonaceous material (brown coal modified by pyrolysis, activation, and enrichment in nitrogen, with two different factor reagents, have been used as adsorbent of phenol from liquid phase. Changes in the phenol content in the test solutions were monitored after subsequent intervals of adsorption with selected adsorbents prepared from organic materials. Significant effect of nitrogen present in the adsorbent material on its adsorption capacity was noted. Sorption capacity of these selected materials was found to depend on the time of use, their surface area, and pore distribution. A conformation to the most well-known adsorption isotherm models, Langmuir, and Freundlich ones, confirms the formation of mono- and heterolayer solute (phenol coverage on the surface of the adsorbent applied herein. The materials proposed as adsorbents of the aqueous solution contaminants were proved effective, which means that the waste materials considered are promising activated carbon precursors for liquid phase adsorbents for the environmental protection.

Gas phase adsorption technology for nitrogen isotope separation and its feasibility for highly enriched nitrogen gas production

International Nuclear Information System (INIS)

Inoue, Masaki; Asaga, Takeo

2000-04-01

Highly enriched nitrogen-15 gas is favorable to reduce radioactive carbon-14 production in reactor. The cost of highly enriched nitrogen-15 gas in mass production is one of the most important subject in nitride fuel option in 'Feasibility Study for FBR and Related Fuel Cycle'. In this work gas phase adsorption technology was verified to be applicable for nitrogen isotope separation and feasible to produce highly enriched nitrogen-15 gas in commercial. Nitrogen isotopes were separated while ammonia gas flows through sodium-A type zeolite column using pressure swing adsorption process. The isotopic ratio of eight samples were measured by high resolution mass spectrometry and Fourier transform microwave spectroscopy. Gas phase adsorption technology was verified to be applicable for nitrogen isotope separation, since the isotopic ratio of nitrogen-15 and nitrogen-14 in samples were more than six times as high as in natural. The cost of highly enriched nitrogen-15 gas in mass production were estimated by the factor method. It revealed that highly enriched nitrogen-15 gas could be supplied in a few hundred yen per gram in mass production. (author)

Effect of packaging material on nitrate nitrogen content of irradiated potatoes

International Nuclear Information System (INIS)

Mondy, N.I.; Koushik, S.R.

1990-01-01

The effect of packaging materials on nitrate nitrogen content of irradiated potatoes was investigated. Tubers were irradiated at 10, 30 and 100 Krads and stored for 12 wk at 5 degrees C in paper or plastic bags. Nitrate nitrogen content was significantly (p 0.01) higher in tubers packaged in plastic as compared to those in paper bags. Irradiation significantly (p 0.01) increased nitrate nitrogen content between the lowest and highest levels of treatment in tubers stored in both paper and plastic bags

Current and future applications of high nitrogen steels

International Nuclear Information System (INIS)

Stein, G.; Hucklenbroich, I.; Feichtinger, H.

1999-01-01

For any new development there are just two gateways into the market: either it does relevant things never done before - in this case the market is ready to pay a considerable price. Or it does the usual things, but at a very competitive price. And of course, there is any combination of these two prerequisites. With nitrogen steels both concepts apply. On one hand there is the idea of substitution, i.e. replacing the expensive nickel by nitrogen. On the other hand there is a production of steels with an unprecedented combination of usually conflicting properties such as superior strength, toughness and corrosion resistance, as represented by the austenitic Cr-Mn-steel P900, which is used for retaining rings. In a way, success of a material and its usages, which become feasible, can be explained by looking at two things: property potential of a new material and process technology for the production of such material. HNS steels are already indispensable in some fields and we can be sure that they will grow to further importance in the near future. This contribution just makes a little round trip through the field of HNS leads from the technology of large scale generators to the world of fashion, from high tech building and wear resistant aircraft bearings and finally even to the world of medicine. (orig.)

A population of highly energetic transient events in the centres of active galaxies

Science.gov (United States)

Kankare, E.; Kotak, R.; Mattila, S.; Lundqvist, P.; Ward, M. J.; Fraser, M.; Lawrence, A.; Smartt, S. J.; Meikle, W. P. S.; Bruce, A.; Harmanen, J.; Hutton, S. J.; Inserra, C.; Kangas, T.; Pastorello, A.; Reynolds, T.; Romero-Cañizales, C.; Smith, K. W.; Valenti, S.; Chambers, K. C.; Hodapp, K. W.; Huber, M. E.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

2017-12-01

Recent all-sky surveys have led to the discovery of new types of transients. These include stars disrupted by the central supermassive black hole, and supernovae that are 10-100 times more energetic than typical ones. However, the nature of even more energetic transients that apparently occur in the innermost regions of their host galaxies is hotly debated1-3. Here we report the discovery of the most energetic of these to date: PS1-10adi, with a total radiated energy of 2.3 × 1052 erg. The slow evolution of its light curve and persistently narrow spectral lines over ˜ 3 yr are inconsistent with known types of recurring black hole variability. The observed properties imply powering by shock interaction between expanding material and large quantities of surrounding dense matter. Plausible sources of this expanding material are a star that has been tidally disrupted by the central black hole, or a supernova. Both could satisfy the energy budget. For the former, we would be forced to invoke a new and hitherto unseen variant of a tidally disrupted star, while a supernova origin relies principally on environmental effects resulting from its nuclear location. Remarkably, we also discover that PS1-10adi is not an isolated case. We therefore surmise that this new population of transients has previously been overlooked due to incorrect association with underlying central black hole activity.

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.

Titanium Nitride and Nitrogen Ion Implanted Coated Dental Materials

Directory of Open Access Journals (Sweden)

David W. Berzins

2012-07-01

Full Text Available Titanium nitride and/or nitrogen ion implanted coated dental materials have been investigated since the mid-1980s and considered in various applications in dentistry such as implants, abutments, orthodontic wires, endodontic files, periodontal/oral hygiene instruments, and casting alloys for fixed restorations. Multiple methodologies have been employed to create the coatings, but detailed structural analysis of the coatings is generally lacking in the dental literature. Depending on application, the purpose of the coating is to provide increased surface hardness, abrasion/wear resistance, esthetics, and corrosion resistance, lower friction, as well as greater beneficial interaction with adjacent biological and material substrates. While many studies have reported on the achievement of these properties, a consensus is not always clear. Additionally, few studies have been conducted to assess the efficacy of the coatings in a clinical setting. Overall, titanium nitride and/or nitrogen ion implanted coated dental materials potentially offer advantages over uncoated counterparts, but more investigation is needed to document the structure of the coatings and their clinical effectiveness.

Comparison between radical- and energetic ion-induced growth of SiCxNy films in plasma immersion ion implantation and deposition

International Nuclear Information System (INIS)

Afanasyev-Charkin, I.V.; Nastasi, M.

2004-01-01

Ternary SiC x N y compounds are materials with some remarkable properties such as high oxidation resistance and high hardness. In this work we compare the properties of SiC x N y films obtained using radio-frequency (rf) and pulsed glow discharge (PGD) plasmas with combinations of SiH 4 , C 2 H 2 , N 2 , and Ar source gases. The pulsed voltage used for the rf deposition was 200 V and for the PGD deposition it was 4 kV. During the rf growth, the growth takes place mostly by attaching neutral radicals to form chemical bonds. In the PGD method, the deposition takes place by subplantation and surface activation by energetic ions. We show that in the case of low-energy RF deposition, a high relative number of C-N bonds with sp 3 hybridization is formed and very few Si-C bonds can be observed. Apparently the growth of carbon nitride and silicon nitride networks takes place independently. This indicates that SiH 3 radicals attach to the dangling bonds of silicon and nitrogen, whereas C 2 H radicals attach to the dangling bonds of carbon and nitrogen. During pulsed glow discharge deposition, bonds between all three components are formed apparently by means of subplantation and damage-induced disorder. The hardness of the PGD films exceed that of the RF films, showing that to form a dense SiC x N y film one has to either supply energy during the growth of the films by heating the substrate, as in the case of chemical vapor deposition or by using energetic ions

Novel nitrogen-doped hierarchically porous coralloid carbon materials as host matrixes for lithium–sulfur batteries

International Nuclear Information System (INIS)

Yang, Jing; Wang, Shuyuan; Ma, Zhipeng; Du, Zhiling; Li, Chunying; Song, Jianjun; Wang, Guiling; Shao, Guangjie

2015-01-01

Highlights: • Nitrogen-doped hierarchically porous coralloid carbon/sulfur composites were prepared • Nitrogen atoms were introduced to improve electrochemical properties • The intriguing structural features benefited discharge capacity and cycling stability - Abstract: Nitrogen-doped hierarchically porous coralloid carbon/sulfur composites (N-HPCC/S) served as attractive cathode materials for lithium–sulfur (Li–S) batteries were fabricated for the first time. The nitrogen-doped hierarchically porous coralloid carbon (N-HPCC) with an appropriate nitrogen content (1.29 wt%) was synthesized via a facile hydrothermal approach, combined with subsequent carbonization–activation. The N-HPCC/S composites prepared by a simple melt–diffusion method displayed an excellent electrochemical performance. With a high sulfur content (58 wt%) in the total electrode weight, the N-HPCC/S cathode delivered a high initial discharge capacity of 1626.8 mA h g −1 and remained high up to 1086.3 mA h g −1 after 50 cycles at 100 mA g −1 , which is about 1.86 times as that of activated carbon. Particularly, the reversible discharge capacity still maintained 607.2 mA h g −1 after 200 cycles even at a higher rate of 800 mA g −1 . The enhanced electrochemical performance was attributed to the synergetic effect between the intriguing hierarchically porous coralloid structure and appropriate nitrogen doping, which could effectively trap polysulfides, alleviate the volume expansion, enhance the electronic conductivity and improve the surface interaction between the carbon matrix and polysulfides

Seeded Reaction Waves in Composites: Fast Structure Transforming Materials that Respond to Energetic Stimuli

Science.gov (United States)

2016-10-21

change in the structure of the capsule system . The temperatures at which the capsules undergo transformation are in accordance with the results in DSC...Structure- Transforming Materials that Respond to Energetic Stimuli Sb. GRANT NUMBER N00014-13-1-0170 Sc. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Sd...encapsulated super- cooled fluids into a polymer matrix allows for rapid changes in mechanical properties. Frontal polymerization within a microvascular

Graphene oxide quantum dot-derived nitrogen-enriched hybrid graphene nanosheets by simple photochemical doping for high-performance supercapacitors

Science.gov (United States)

Xu, Yongjie; Li, Xinyu; Hu, Guanghui; Wu, Ting; Luo, Yi; Sun, Lang; Tang, Tao; Wen, Jianfeng; Wang, Heng; Li, Ming

2017-11-01

Nitrogen-enriched graphene was fabricated via a facile strategy. Graphene oxide (GO) nanosheets and graphene oxide quantum dots (GQDs) were used as a structure-directing agent and in situ activating agent, respectively, after photoreduction under NH3 atmosphere. The combination of photoreduction and NH3 not only reduced GO and GQD composites (GO/GQDs) within a shorter duration but also doped a high level of nitrogen on the composites (NrGO/GQDs). The nitrogen content of NrGO/GQDs reached as high as 18.86 at% within 5 min of irradiation. Benefiting from the nitrogen-enriched GO/GQDs hybrid structure, GQDs effectively prevent the agglomeration of GO sheets and increased the numbers of ion channels in the material. Meanwhile, the high levels of nitrogen improved electrical conductivity and strengthened the binding energy between GQD and GO sheets. Compared with reduced GO and low nitrogen-doped reduced GO, NrGO/GQD electrodes exhibited better electrochemical characteristics with a high specific capacitance of 344 F g-1 at a current density of 0.25 A g-1. Moreover, the NrGO/GQD electrodes exhibited 82% capacitance retention after 3000 cycles at a current density of 0.8 A g-1 in 6 M KOH electrolyte. More importantly, the NrGO/GQD electrodes deliver a high energy density of 43 Wh kg-1 at a power density of 417 W kg-1 in 1 M Li2SO4 electrolyte. The nitrogen-doped graphene and corresponding supercapacitor presented in this study are novel materials with potential applications in advanced energy storage systems.

Delay in solar energetic particle onsets at high heliographic latitudes

Directory of Open Access Journals (Sweden)

S. Dalla

2003-06-01

Full Text Available Ulysses observations have shown that solar energetic particles (SEPs can easily reach high heliographic latitudes. To obtain information on the release and propagation of SEPs prior to their arrival at Ulysses, we analyse the onsets of nine large high-latitude particle events. We measure the onset times in several energy channels, and plot them versus inverse particle speed. This allows us to derive an experimental path length and time of release from the solar atmosphere. We repeat the procedure for near-Earth observations by Wind and SOHO. We find that the derived path lengths at Ulysses are 1.06 to 2.45 times the length of a Parker spiral magnetic field line connecting the spacecraft to the Sun. The time of particle release from the Sun is between 100 and 350 min later than the release time derived from in-ecliptic measurements. We find no evidence of correlation between the delay in release and the inverse of the speed of the CME associated with the event, or the inverse of the speed of the corresponding interplanetary shock. The main parameter determining the magnitude of the delay appears to be the difference in latitude between the flare and the footpoint of the spacecraft.Key words. Interplanetary physics (energetic particles – Solar physics, astrophysics and astronomy (energetic particles, flares and mass ejections

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.

Study of the degradation process of polyimide induced by high energetic ion irradiation

International Nuclear Information System (INIS)

Severin, Daniel

2008-01-01

The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10 10 -5 x 10 12 ions/cm 2 ). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10 10 ions/cm 2 ). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO 2 , and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a critical material degradation which

Study of the degradation process of polyimide induced by high energetic ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Severin, Daniel

2008-09-19

The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10{sup 10}-5 x 10{sup 12} ions/cm{sup 2}). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10{sup 10} ions/cm{sup 2}). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO{sub 2}, and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a

Investigation of the imaging properties of inorganic scintillation screens using high energetic ion beams

Energy Technology Data Exchange (ETDEWEB)

Lieberwirth, Alice [TU Darmstadt (Germany); JWG Universitaet Frankfurt/Main (Germany); Forck, Peter; Sieber, Thomas [GSI Darmstadt (Germany); Ensinger, Wolfgang; Lederer, Stephan [TU Darmstadt (Germany); Kester, Oliver [JWG Universitaet Frankfurt/Main (Germany)

2016-07-01

Inorganic scintillation screens are a common diagnostics tool in heavy ion accelerators. In order to investigate the imaging properties of various screen materials, four different material compositions were irradiated at GSI, using protons up to Uranium ions as projectiles. Beams were extracted from SIS18 with high energy (300 MeV/u) in slow and fast extraction mode. During irradiation the scintillation response of the screens was simultaneously recorded by two different optical setups to investigate light output, profile characteristics and emission spectra. It was observed, that fast extracted beams induce in general lower light output than slow extracted beams, while the light output per deposited energy decreases with atomic number. The analysis of the spectral emission as well as investigations with classical optical methods showed no significant defect-building in all materials, not even under irradiation with increasing beam intensity or over long time periods. The investigated scintillation screens can be considered as stable under irradiation with high energetic heavy ion pulses and are appropriate for beam diagnostics applications in future accelerator facilities like FAIR. Characteristic properties and application areas of the screens are presented in the poster.

Rapid startup and high rate nitrogen removal from anaerobic sludge digester liquor using a SNAP process.

Science.gov (United States)

Qiao, Sen; Nishiyama, Takashi; Fujii, Tatsuo; Bhatti, Zafar; Furukawa, Kenji

2012-02-01

In this study, a single-stage autotrophic nitrogen removal reactor, packed with a novel acrylic fiber biomass carrier material (Biofix), was applied for nitrogen removal from sludge digester liquor. For rapid start-up, conventional activated sludge was added to the reactor soon after the attachment of anammox biomass on the Biofix carriers, which allowed conventional activated sludge to form a protective layer of biofilm around the anammox biomass. The Nitrogen removal efficiency reached 75% within 1 week at a nitrogen loading rate of 0.46 kg-N/m(3)/day for synthetic wastewater treatment. By the end of the synthetic wastewater treatment period, the maximum nitrogen removal rate had increased to 0.92 kg-N/m(3)/day at a nitrogen loading rate of 1.0 kg-N/m(3)/day. High nitrogen removal rate was also achieved during the actual raw digester liquor treatment with the highest nitrogen removal rate being 0.83 kg-N/m(3)/day at a nitrogen loading rate of 0.93 kg-N/m(3)/day. The thick biofilm on Biofix carriers allowed anammox bacteria to survive under high DO concentration of 5-6 mg/l resulting in stable and high nitrogen removal performance. FISH and CLSM analysis demonstrated that anammox bacteria coexisted and surrounded by ammonium oxidizing bacteria.

Facile preparation of nitrogen-doped hierarchical porous carbon with high performance in supercapacitors

International Nuclear Information System (INIS)

Yan, Kun; Kong, Ling-Bin; Shen, Kui-Wen; Dai, Yan-Hua; Shi, Ming; Hu, Bing; Luo, Yong-Chun; Kang, Long

2016-01-01

Graphical abstract: Preparing and activating process of nitrogen-doped hierarchical porous carbon (NHPC). - Highlights: • The well-defined PAN-b-PMMA copolymer was synthesized by atom transfer radical polymerization with narrow molecular weight distribution. • Nitrogen-doped hierarchical porous structure (NHPC) was prepared through a simple carbonization procedure of PAN-b-PMMA precursor. • NHPC possessed hierarchical porous structure with high BET surface area of 257 m"2 g"−"1 and DFT mesopore size of 14.61 nm. • Effects of activation conditions on supercapacitive behavior were systematically studied. - Abstract: The nitrogen-doped hierarchical porous carbon (NHPC) material was successfully prepared through a simple carbonization procedure of well-defined diblock copolymer precursor containing nitrogen-enriched carbon source, i.e., polyacrylonitrile (PAN), and asacrificial block, i.e., polymethylmethacrylate (PMMA). PAN-b-PMMA diblock copolymer was synthesized by atom transfer radical polymeriation (ATRP) with narrow molecular weight distribution. The as-obtained NHPC possessed nitrogen-doped hierarchical porous structure with high BET surface area of 257 m"2 g"−"1 and Nonlocal density functional theory (NLDFT) mesopore size of 14.61 nm. Surface activated nitrogen-doped hierarchical porous carbon (A-NHPC) materials were obtained by subsequent surface activation with HNO_3 solution. The effects of activation conditions on supercapacitive behavior were systematically studied, a maximum specific capacitance of 314 F g"−"1 at a current density of 0.5 A g"−"1 was achieved in 2 M KOH aqueous electrolyte. Simultaneously, it exhibited excellent rate capability of 67.8% capacitance retention as the current density increased from 0.5 to 20 A g"−"1 and superior cycling performance of 90% capacitance retention after 10,000 cycles at the current density of 2 A g"−"1.

Facile preparation of nitrogen-doped hierarchical porous carbon with high performance in supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Yan, Kun [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Kong, Ling-Bin, E-mail: konglb@lut.cn [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Shen, Kui-Wen; Dai, Yan-Hua; Shi, Ming; Hu, Bing [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Luo, Yong-Chun; Kang, Long [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China)

2016-02-28

Graphical abstract: Preparing and activating process of nitrogen-doped hierarchical porous carbon (NHPC). - Highlights: • The well-defined PAN-b-PMMA copolymer was synthesized by atom transfer radical polymerization with narrow molecular weight distribution. • Nitrogen-doped hierarchical porous structure (NHPC) was prepared through a simple carbonization procedure of PAN-b-PMMA precursor. • NHPC possessed hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and DFT mesopore size of 14.61 nm. • Effects of activation conditions on supercapacitive behavior were systematically studied. - Abstract: The nitrogen-doped hierarchical porous carbon (NHPC) material was successfully prepared through a simple carbonization procedure of well-defined diblock copolymer precursor containing nitrogen-enriched carbon source, i.e., polyacrylonitrile (PAN), and asacrificial block, i.e., polymethylmethacrylate (PMMA). PAN-b-PMMA diblock copolymer was synthesized by atom transfer radical polymeriation (ATRP) with narrow molecular weight distribution. The as-obtained NHPC possessed nitrogen-doped hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and Nonlocal density functional theory (NLDFT) mesopore size of 14.61 nm. Surface activated nitrogen-doped hierarchical porous carbon (A-NHPC) materials were obtained by subsequent surface activation with HNO{sub 3} solution. The effects of activation conditions on supercapacitive behavior were systematically studied, a maximum specific capacitance of 314 F g{sup −1} at a current density of 0.5 A g{sup −1} was achieved in 2 M KOH aqueous electrolyte. Simultaneously, it exhibited excellent rate capability of 67.8% capacitance retention as the current density increased from 0.5 to 20 A g{sup −1} and superior cycling performance of 90% capacitance retention after 10,000 cycles at the current density of 2 A g{sup −1}.

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.

Active interrogation using energetic protons

International Nuclear Information System (INIS)

Morris, Christopher L.; Chung, Kiwhan; Greene, Steven J.; Hogan, Gary E.; Makela, Mark; Mariam, Fesseha; Milner, Edward C.; Murray, Matthew; Saunders, Alexander; Spaulding, Randy; Wang, Zhehui; Waters, Laurie; Wysocki, Frederick

2010-01-01

Energetic proton beams provide an attractive alternative when compared to electromagnetic and neutron beams for active interrogation of nuclear threats because they have large fission cross sections, long mean free paths and high penetration, and they can be manipulated with magnetic optics. We have measured time-dependent cross sections and neutron yields for delayed neutrons and gamma rays using 800 MeV and 4 GeV proton beams with a set of bare and shielded targets. The results show significant signals from both unshielded and shielded nuclear materials. Measurements of neutron energies yield suggest a signature unique to fissile material. Results are presented in this paper.

Facile Synthesis of ZnO Nanoparticles on Nitrogen-Doped Carbon Nanotubes as High-Performance Anode Material for Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Haipeng Li

2017-09-01

Full Text Available ZnO/nitrogen-doped carbon nanotube (ZnO/NCNT composite, prepared though a simple one-step sol-gel synthetic technique, has been explored for the first time as an anode material. The as-prepared ZnO/NCNT nanocomposite preserves a good dispersity and homogeneity of the ZnO nanoparticles (~6 nm which deposited on the surface of NCNT. Transmission electron microscopy (TEM reveals the formation of ZnO nanoparticles with an average size of 6 nm homogeneously deposited on the surface of NCNT. ZnO/NCNT composite, when evaluated as an anode for lithium-ion batteries (LIBs, exhibits remarkably enhanced cycling ability and rate capability compared with the ZnO/CNT counterpart. A relatively large reversible capacity of 1013 mAh·g−1 is manifested at the second cycle and a capacity of 664 mAh·g−1 is retained after 100 cycles. Furthermore, the ZnO/NCNT system displays a reversible capacity of 308 mAh·g−1 even at a high current density of 1600 mA·g−1. These electrochemical performance enhancements are ascribed to the reinforced accumulative effects of the well-dispersed ZnO nanoparticles and doping nitrogen atoms, which can not only suppress the volumetric expansion of ZnO nanoparticles during the cycling performance but also provide a highly conductive NCNT network for ZnO anode.

Biomass derived nitrogen-doped hierarchical porous carbon sheets for supercapacitors with high performance.

Science.gov (United States)

Wang, Cunjing; Wu, Dapeng; Wang, Hongju; Gao, Zhiyong; Xu, Fang; Jiang, Kai

2018-08-01

A facile potassium chloride salt-locking technique combined with hydrothermal treatment on precursors was explored to prepare nitrogen-doped hierarchical porous carbon sheets in air from biomass. Benefiting from the effective synthesis strategy, the as-obtained carbon possesses a unique nitrogen-doped thin carbon sheet structure with abundant hierarchical pores and large specific surface areas of 1459 m 2  g -1 . The doped nitrogen in carbon framework has a positive effect on the electrochemical properties of the electrode material, the thin carbon sheet structure benefits for fast ion transfer, the abundant meso-pores provide convenient channels for rapid charge transportation, large specific surface area and lots of micro-pores guarantee sufficient ion-storage sites. Therefore, applied for supercapacitors, the carbon electrode material exhibits an outstanding specific capacitance of 451 F g -1 at 0.5 A g -1 in a three-electrode system. Moreover, the assembled symmetric supercapacitor based on two identical carbon electrodes also displays high specific capacitance of 309 F g -1 at 0.5 A g -1 , excellent rate capacity and remarkable cycling stability with 99.3% of the initial capacitance retention after 10,000 cycles at 5 A -1 . The synthesis strategy avoids expensive inert gas protection and the use of corrosive KOH and toxic ZnCl 2 activated reagents, representing a promising green route to design advanced carbon electrode materials from biomass for high-capacity supercapacitors. Copyright © 2018. Published by Elsevier Inc.

Binding SnO2 nanocrystals in nitrogen-doped graphene sheets as anode materials for lithium-ion batteries.

Science.gov (United States)

Zhou, Xiaosi; Wan, Li-Jun; Guo, Yu-Guo

2013-04-18

Hybrid anode materials for Li-ion batteries are fabricated by binding SnO2 nanocrystals (NCs) in nitrogen-doped reduced graphene oxide (N-RGO) sheets by means of an in situ hydrazine monohydrate vapor reduction method. The SnO2NCs in the obtained SnO2NC@N-RGO hybrid material exhibit exceptionally high specific capacity and high rate capability. Bonds formed between graphene and SnO2 nanocrystals limit the aggregation of in situ formed Sn nanoparticles, leading to a stable hybrid anode material with long cycle life. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulation of the decomposition and nitrogen mineralization of aboveground plant material in two unfertilized grassland ecosystems.

NARCIS (Netherlands)

Bloemhof, H.S.; Berendse, F.

1995-01-01

A simple model of the decomposition and nitrogen mineralization of plant material from two unfertilized grassland ecosystems has been developed, with only the proportion of leaves and stems in the original material, the initial nitrogen contents of these plant parts and temperature as input data.

Nitrogen and oxygen co-doped carbon nanofibers with rich sub-nanoscale pores as self-supported electrode material of high-performance supercapacitors

International Nuclear Information System (INIS)

Li, Qun; Xie, Wenhe; Liu, Dequan; Wang, Qi; He, Deyan

2016-01-01

Self-supported porous carbon nanofibers (CNFs) network has been prepared by electrospinning technology assisted with template method. The as-prepared material is rich in sub-nanoscale pores and nitrogen and oxygen functional groups, which can serve as a fast conductive network with abundant electrochemical active sites and greatly facilitates the transport of electrons and ions. When the porous CNFs network is used as an electrode for supercapacitor in a three electrode system, it displays a high capacitance of 233.1 F/g at 0.2 A/g, and a capacitance of 130.2 F/g even at 14 A/g. It maintains a capacitance of 154.0 F/g with 90.17% retention after 4000 cycles at 2 A/g. Moreover, the assembled symmetric supercapacitor not only exhibits excellent rate capability and cycle performance, but also delivers an energy density of 4.17 Wh/kg and a power density of 2500 W/kg. The experimental results demonstrate that the prepared N, O co-doped carbon nanofibers with rich sub-nanoscale pores are a promising electrode material for high-performance supercapacitors.

Observation of enhanced radial transport of energetic ion due to energetic particle mode destabilized by helically-trapped energetic ion in the Large Helical Device

Science.gov (United States)

Ogawa, K.; Isobe, M.; Kawase, H.; Nishitani, T.; Seki, R.; Osakabe, M.; LHD Experiment Group

2018-04-01

A deuterium experiment was initiated to achieve higher-temperature and higher-density plasmas in March 2017 in the Large Helical Device (LHD). The central ion temperature notably increases compared with that in hydrogen experiments. However, an energetic particle mode called the helically-trapped energetic-ion-driven resistive interchange (EIC) mode is often excited by intensive perpendicular neutral beam injections on high ion-temperature discharges. The mode leads to significant decrease of the ion temperature or to limiting the sustainment of the high ion-temperature state. To understand the effect of EIC on the energetic ion confinement, the radial transport of energetic ions is studied by means of the neutron flux monitor and vertical neutron camera newly installed on the LHD. Decreases of the line-integrated neutron profile in core channels show that helically-trapped energetic ions are lost from the plasma.

Energetic contaminants inhibit plant litter decomposition in soil.

Science.gov (United States)

Kuperman, Roman G; Checkai, Ronald T; Simini, Michael; Sunahara, Geoffrey I; Hawari, Jalal

2018-05-30

Individual effects of 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), nitroglycerin (NG), and 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) on litter decomposition, an essential biologically-mediated soil process, were assessed using Orchard grass (Dactylis glomerata) straw in Sassafras sandy loam (SSL) soil, which has physicochemical characteristics that support "very high" qualitative relative bioavailability for organic chemicals. Batches of SSL soil were separately amended with individual EMs or acetone carrier control. To quantify the decomposition rates, one straw cluster was harvested from a set of randomly selected replicate containers from within each treatment, after 1, 2, 3, 4, 6, and 8 months of exposure. Results showed that soil amended with 2,4-DNT or NG inhibited litter decomposition rates based on the median effective concentration (EC50) values of 1122 mg/kg and 860 mg/kg, respectively. Exposure to 2-ADNT, 4-ADNT or CL-20 amended soil did not significantly affect litter decomposition in SSL soil at ≥ 10,000 mg/kg. These ecotoxicological data will be helpful in identifying concentrations of EMs in soil that present an acceptable ecological risk for biologically-mediated soil processes. Published by Elsevier Inc.

Criticality conditions of heterogeneous energetic materials under shock loading

Science.gov (United States)

Nassar, Anas; Rai, Nirmal Kumar; Sen, Oishik; Udaykumar, H. S.

2017-06-01

Shock interaction with the microstructural heterogeneities of energetic materials can lead to the formation of locally heated regions known as hot spots. These hot spots are the potential sites where chemical reaction may be initiated. However, the ability of a hot spot to initiate chemical reaction depends on its size, shape and strength (temperature). Previous study by Tarver et al. has shown that there exists a critical size and temperature for a given shape (spherical, cylindrical, and planar) of the hot spot above which reaction initiation is imminent. Tarver et al. assumed a constant temperature variation in the hot spot. However, the meso-scale simulations show that the temperature distribution within a hot spot formed from processes such as void collapse is seldom constant. Also, the shape of a hot spot can be arbitrary. This work is an attempt towards development of a critical hot spot curve which is a function of loading strength, duration and void morphology. To achieve the aforementioned goal, mesoscale simulations are conducted on porous HMX material. The process is repeated for different loading conditions and void sizes. The hot spots formed in the process are examined for criticality depending on whether they will ignite or not. The metamodel is used to obtain criticality curves and is compared with the critical hot spot curve of Tarver et al.

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.

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.

Fatigue damage evolution of cold-worked austenitic nickel-free high-nitrogen steel X13CrMnMoN18-14-3 (1.4452)

Energy Technology Data Exchange (ETDEWEB)

Tikhovskiy, I.; Weiss, S.; Fischer, A. [Univ. of Duisburg-Essen, Materials Science and Engineering II, Duisburg (Germany)

2004-07-01

Due to the fact that the risk of Ni-allergies becomes more and more important for modern therapies, the necessity of Ni-free implant materials becomes increasingly important. Beside Co- and Ti-base alloys Ni-free high-nitrogen steels may offer an attractive alternative. The present work presents the austenitic high-nitrogen and nickel-free steel X13CrMnMoN18-14-3, (Material No.: 1.4452) after 20% cold-working. In addition this material was deformed under axial cyclic total strain controlled fatigue tests at room temperature. The development of dislocation structure due to different loading amplitudes was compared to none cyclically deformed material. The good mechanical und fatigue properties of these austenitic high-nitrogen steels as well as the better tribological, chemical and biological properties compared to CrNiMo-steels qualify these steels as a promising alternative in medical applications. (orig.)

Structural and Chemical Properties of the Nitrogen-Rich Energetic Material Triaminoguanidinium 1-methyl-5-nitriminotetrazolate under Pressure

Science.gov (United States)

2012-08-01

ABSTRACT 16. SECURITY CLASSIFICATION OF: The structural and chemical properties of the bi-molecular, hydrogen-bonded, nitrogen-rich ener- getic...School Apprenticeship Program (ARO-HSAP), and the Depart- ment of Energy National Nuclear Security Administration (Carnegie/DOE Alliance Center; DE-FC52...B. J. Baer, H. Cynn, W. J. Evans, V. Iota , and C. S. Yoo, Phys. Rev. B 76(1), 014113 (2007). 9T. M. Klapötke, J. Stierstorfer, and A. U. Wallek, Chem

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.

Toxicity Determinations for Five Energetic Materials, Weathered and Aged in Soil, to the Collembolan Folsomia Candida

Science.gov (United States)

2015-03-01

obtained from the Soil Fauna and Ecotoxicology Research Unit, Department of Terrestrial Ecology, National Environmental Research Institute (Silkeborg...AND AGED IN SOIL , TO THE COLLEMBOLAN FOLSOMIA CANDIDA ECBC-TR-1273 Carlton T. Phillips Ronald T. Checkai Roman G. Kuperman Michael Simini...for Five Energetic Materials, Weathered and Aged in Soil , to the Collembolan Folsomia candida 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

Heavily Graphitic-Nitrogen Self-doped High-porosity Carbon for the Electrocatalysis of Oxygen Reduction Reaction

Science.gov (United States)

Feng, Tong; Liao, Wenli; Li, Zhongbin; Sun, Lingtao; Shi, Dongping; Guo, Chaozhong; Huang, Yu; Wang, Yi; Cheng, Jing; Li, Yanrong; Diao, Qizhi

2017-11-01

Large-scale production of active and stable porous carbon catalysts for oxygen reduction reaction (ORR) from protein-rich biomass became a hot topic in fuel cell technology. Here, we report a facile strategy for synthesis of nitrogen-doped porous nanocarbons by means of a simple two-step pyrolysis process combined with the activation of zinc chloride and acid-treatment process, in which kidney bean via low-temperature carbonization was preferentially adopted as the only carbon-nitrogen sources. The results show that this carbon material exhibits excellent ORR electrocatalytic activity, and higher durability and methanol-tolerant property compared to the state-of-the-art Pt/C catalyst for the ORR, which can be mainly attributed to high graphitic-nitrogen content, high specific surface area, and porous characteristics. Our results can encourage the synthesis of high-performance carbon-based ORR electrocatalysts derived from widely-existed natural biomass.

Reference material certification of chinese cabbage composition for selenium, nitrogen, phosphorus and potassium content

Directory of Open Access Journals (Sweden)

D. A. Chupakhin

2016-01-01

Full Text Available Rationale. The reference material of composition with the established metrological characteristics including a certified value and an expanded uncertainty is necessary to ensure an effective accuracy and precision control of results of element composition determination in food ingredients and products. This paper represents the development of a reference material of food crop composition for selenium, nitrogen, phosphorus and potassium content. Methods. To identify the selenium the hybrid atomic absorption method was used, to identify the nitrogen and phosphorus the photometric method was used, to determine the potassium flame-photometric method was used. When determining the metrological characteristics of the reference material the Russian national instructions and recommendations MI 3174-2009 and P 50.2.058-2007 were applied. Results. Based on the research findings the reference material of Chinese cabbage composition with a certified value and an expanded uncertainty was developed: for selenium 0.044 ± 0.017 mg/kg; for nitrogen 4.09 ± 0.27 %; for phosphorus 0.69 ± 0.14 %; for potassium 2.87 ± 0.22 %.

Structural behaviour of nitrogen in oxide ceramics

International Nuclear Information System (INIS)

Ghauri, K.M.

1997-01-01

The solubility of nitrogen in molten oxides has significant consideration for two quite different types of engineering materials. The implication of a knowledge of the role of nitrogen in these oxides for refining high nitrogen steels in obvious but similar nitrogen-bearing oxide melts are of critical importance in the densification of silicon nitride ceramics. Present paper discusses structural behaviour and phase equilibria qualitatively in the light of knowledge available on slag structure through infrared and x-ray diffraction. Nitrogen solubility in glasses and related sialon based ceramics may be of paramount importance to understand the role of nitrogen in these materials as these oxides are similar in composition, structure and characteristics to sintering glasses in nitrogen ceramics. It is quite logical to infer that the same oxide model can be applied in order to massively produce nitrogen alloyed steels which are actively competing to be the materials of the next century. (author)

Pseudocapacitance of amorphous TiO2@nitrogen doped graphene composite for high rate lithium storage

International Nuclear Information System (INIS)

Li, Sheng; Xue, Pan; Lai, Chao; Qiu, Jingxia; Ling, Min; Zhang, Shanqing

2015-01-01

The high rate applications such as electric vehicles of the traditional lithium ion batteries (LIBs) are commonly limited by their insufficient electron conductivity and slow mass transport of lithium ions in bulk electrode materials. In order to address these issues, in this work, a simple and up-scalable wet-mechanochemical (wet-ball milling) route has been developed for fabrication of amorphous porous TiO 2 @nitrogen doped graphene (TiO 2 @N-G) nanocomposites. The amorphous phase, unique porous structure of TiO 2 and the surface defects from nitrogen doping to graphene planes have incurred surface controlled reactions, contributing pseudocapacitance to the total capacity of the battery. It plays a dominant role in producing outstanding high rate electrochemical performance, e.g., 182.7 mAh/g (at 3.36 A/g) after 100 cycles. The design and synthesis of electrode materials with enhanced conductivity and surface pseudocapacitance can be a promising way for high rate LIBs.

Green colorants based on energetic azole borates.

Science.gov (United States)

Glück, Johann; Klapötke, Thomas M; Rusan, Magdalena; Stierstorfer, Jörg

2014-11-24

The investigation of green-burning boron-based compounds as colorants in pyrotechnic formulations as alternative for barium nitrate, which is a hazard to health and to the environment, is reported. Metal-free and nitrogen-rich dihydrobis(5-aminotetrazolyl)borate salts and dihydrobis(1,3,4-triazolyl)borate salts have been synthesized and characterized by NMR spectroscopy, elemental analysis, mass spectrometry, and vibrational spectroscopy. Their thermal and energetic properties have been determined as well. Several pyrotechnic compositions using selected azolyl borate salts as green colorants were investigated. Formulations with ammonium dinitramide and ammonium nitrate as oxidizers and boron and magnesium as fuels were tested. The burn time, dominant wavelength, spectral purity, luminous intensity, and luminous efficiency as well as the thermal and energetic properties of these compositions were measured. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bacterial nitrogen fixation in sand bioreactors treating winery wastewater with a high carbon to nitrogen ratio.

Science.gov (United States)

Welz, Pamela J; Ramond, Jean-Baptiste; Braun, Lorenz; Vikram, Surendra; Le Roes-Hill, Marilize

2018-02-01

Heterotrophic bacteria proliferate in organic-rich environments and systems containing sufficient essential nutrients. Nitrogen, phosphorus and potassium are the nutrients required in the highest concentrations. The ratio of carbon to nitrogen is an important consideration for wastewater bioremediation because insufficient nitrogen may result in decreased treatment efficiency. It has been shown that during the treatment of effluent from the pulp and paper industry, bacterial nitrogen fixation can supplement the nitrogen requirements of suspended growth systems. This study was conducted using physicochemical analyses and culture-dependent and -independent techniques to ascertain whether nitrogen-fixing bacteria were selected in biological sand filters used to treat synthetic winery wastewater with a high carbon to nitrogen ratio (193:1). The systems performed well, with the influent COD of 1351 mg/L being reduced by 84-89%. It was shown that the nitrogen fixing bacterial population was influenced by the presence of synthetic winery effluent in the surface layers of the biological sand filters, but not in the deeper layers. It was hypothesised that this was due to the greater availability of atmospheric nitrogen at the surface. The numbers of culture-able nitrogen-fixing bacteria, including presumptive Azotobacter spp. exhibited 1-2 log increases at the surface. The results of this study confirm that nitrogen fixation is an important mechanism to be considered during treatment of high carbon to nitrogen wastewater. If biological treatment systems can be operated to stimulate this phenomenon, it may obviate the need for nitrogen addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

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 Ballistic Organization Cape Town, South Africa 27-29 September 2016 1 PREDICTION OF DETONATION AND JWL EOS PARAMETERS OF ENERGETIC MATERIALS USING EXPLO5 COMPUTER CODE X. Peter*, Z. Jiba, M. Olivier, I.M. Snyman, F.J. Mostert and T.J. Sono.... Nowadays many numerical methods and programs are being used for carrying out thermodynamic calculations of the detonation parameters of condensed explosives, for example a BKW Fortran (Mader, 1967), Ruby (Cowperthwaite and Zwisler, 1974) TIGER...

Microstructure and tribology of carbon, nitrogen, and oxygen implanted ferrous materials

International Nuclear Information System (INIS)

Williamson, D.L.

1993-01-01

Nitrogen, carbon, and oxygen ions have been implanted into ferrous materials under unusual conditions of elevated temperatures and very high dose rates. The tribological durabilities of the resulting surfaces are examined with a special type of pin-on-disc wear test apparatus and found in most cases to be dramatically improved compared to surfaces prepared with conventional implantation conditions. Near-surface microstructures and compositions are characterized after implantation and after wear testing by backscatter Moessbauer spectroscopy, X-ray diffraction, scanning electron microscopy, and Auger electron spectroscopy. These data provide evidence for the predominant mechanisms responsible for the observed sliding wear behavior induced by each of the three species. (orig.)

Nitrogen-doped diamond electrode shows high performance for electrochemical reduction of nitrobenzene

International Nuclear Information System (INIS)

Zhang, Qing; Liu, Yanming; Chen, Shuo; Quan, Xie; Yu, Hongtao

2014-01-01

Highlights: • A metal-free nitrogen-doped diamond electrode was synthesized. • The electrode exhibits high electrocatalytic activity for nitrobenzene reduction. • The electrode exhibits high selectivity for reduction of nitrobenzene to aniline. • High energy efficiency was obtained compared with graphite electrode. -- Abstract: Effective electrode materials are critical to electrochemical reduction, which is a promising method to pre-treat anti-oxidative and bio-refractory wastewater. Herein, nitrogen-doped diamond (NDD) electrodes that possess superior electrocatalytic properties for reduction were fabricated by microwave-plasma-enhanced chemical vapor deposition technology. Nitrobenzene (NB) was chosen as the probe compound to investigate the material's electro-reduction activity. The effects of potential, electrolyte concentration and pH on NB reduction and aniline (AN) formation efficiencies were studied. NDD exhibited high electrocatalytic activity and selectivity for reduction of NB to AN. The NB removal efficiency and AN formation efficiency were 96.5% and 88.4% under optimal conditions, respectively; these values were 1.13 and 3.38 times higher than those of graphite electrodes. Coulombic efficiencies for NB removal and AN formation were 27.7% and 26.1%, respectively; these values were 4.70 and 16.6 times higher than those of graphite electrodes under identical conditions. LC–MS analysis revealed that the dominant reduction pathway on the NDD electrode was NB to phenylhydroxylamine (PHA) to AN

Material-related issues at high-power and high-energy ion beam facilities

CERN Document Server

Bender, M.; Tomut, M.; Trautmann, C.

2015-01-01

When solids are exposed to energetic ions (MeV-GeV), their physical and chemical structure can be severely modified. The change is governed by ultrafast dynamical processes starting from the deposition of large energy densities, electronic excitation and ionization processes, and finally damage creation in the atomic lattice system. In many materials, each projectile creates a cylindrical track with a few nanometers in diameter and up to many μm in length. To study and monitor the creation of damage, the GSI irradiation facility dedicated to materials science provides different in-situ and on-line techniques such as high resolution microscopy, X-ray diffraction, optical absorption spectroscopy, thermal imaging and residual gas analysis. The irradiation experiments can be performed under various gas atmospheres and under cryogenic or elevated temperature.

A diffraction limited nitrogen laser for detector calibration in high energy physics

International Nuclear Information System (INIS)

Hartjes, F.G.

1990-01-01

This thesis consists of two parts. In part I the operation of a pulsed two-stage nitrogen laser is described. In contrast to most other lasers an optical resonator can not be used in a nitrogen laser because of the very short pulse time (∼ 1 ns). Therefore the emitted beam of a simple nitrogen laser has a large divergence. A nitrogen laser with a small beam divergence however can be constructed via the 'Master Oscillator Power Amplifier' principle. Herein a double nitrogen laser system is employed in which both lasers fire simultaneously. The diameter of the laser beam from the first stage (oscillator) is enlarged by a telescope by which the divergence decreases strongly. In a second stage (amplifier) subsequently the weak laser beam is amplified again. The outcoming beam has an elongated diameter which is changed in an approximately round form by a telescope of two cylindrical lenses. The process leading to the formation of population inversion in the nitrogen causing emission of laser ligth is described. The electric circuit, which delivers the high-voltage pulse causing the electric discharge in the laser cavity, is described. The mechanical construction of the laser, in particular with regard to the choices of the materials, is described. Finally, the optical system of the two-stage nitrogen laser is explained. In part II the application of the two-stage nitrogen laser in high-energy physics is treated. Instructions are given about the practical use of the laser: the usual optical system and the ionization profile to be expected in the detector gas. Herein three different kinds of beams are distinguished: the parallel beam, the weakly focussed, and the strongly focussed beam. Some examples are given of the use of the laser: a time very close to the wire, the outlining of the drift wire chambers with a long parallel beam, and the measurement of optical properties of scintillating plastic fibers. (author). 52 refs.; 76 figs.; 4 tabs

Energetic optimization of regenerative braking for high speed railway systems

International Nuclear Information System (INIS)

Frilli, Amedeo; Meli, Enrico; Nocciolini, Daniele; Pugi, Luca; Rindi, Andrea

2016-01-01

Highlights: • A model of longitudinal dynamics of the High-speed train ETR1000 is presented. • The model includes on board traction and braking subsystems. • Interactions between overhead line and power line are modelled. • The model is validated on real experimental data. • An energy storage strategy for a high-speed line is proposed. - Abstract: The current development trend in the railway field has led to an ever increasing interest for the energetic optimization of railway systems (especially considering the braking phases), with a strong attention to the mutual interactions between the loads represented by railway vehicles and the electrical infrastructure, including all the sub-systems related to distribution and smart energy management such as energy storage systems. In this research work, the authors developed an innovative coupled modelling approach suitable for the analysis of the energetic optimization of railway systems and based on the use of the new object oriented language Matlab-Simscape™, which presents several advantages with respect to conventional modelling tools. The proposed model has been validated considering an Italian Direct Current High-speed line and the High-speed train ETR 1000. Furthermore, the model has been used to perform an efficiency analysis, considering the use of energy storage devices. The results obtained with the developed model show that the use of energy recovery systems in high-speed railway can provide great opportunities of energy savings.

Continuous engineering of nano-cocrystals for medical and energetic applications

Science.gov (United States)

Spitzer, D.; Risse, B.; Schnell, F.; Pichot, V.; Klaumünzer, M.; Schaefer, M. R.

2014-10-01

Cocrystals, solid mixtures of different molecules on molecular scale, are supposed to be tailor made materials with improved employability compared to their pristine individual components in domains such as medicine and explosives. In medicine, cocrystals are obtained by crystallization of active pharmaceutical ingredients with precisely chosen coformers to design medicaments that demonstrate enhanced stability, high solubility, and therefore high bioavailability and optimized drug up-take. Nanoscaling may further advance these characteristica compared to their micronsized counterparts - because of a larger surface to volume ratio of nanoparticles. In the field of energetic materials, cocrystals offer the opportunity to design smart explosives, combining high reactivity with significantly reduced sensitivity, nowadays essential for a safe manipulation and handling. Furthermore, cocrystals are used in ferroelectrics, non-linear material response and electronic organics. However, state of the art batch processes produce low volume of cocrystals of variable quality and only have produced micronsized cocrystals so far, no nano-cocrystals. Here we demonstrate the continuous preparation of pharmaceutical and energetic micro- and nano-cocrystals using the Spray Flash Evaporation process. Our laboratory scale pilot plant continuously prepared up to 8 grams per hour of Caffeine/Oxalic acid 2:1, Caffeine/Glutaric acid 1:1, TNT/CL-20 1:1 and HMX/Cl-20 1:2 nano- and submicronsized cocrystals.

Building energetic material from novel salix leaf-like CuO and nano-Al through electrophoretic deposition

Energy Technology Data Exchange (ETDEWEB)

Yin, Yan Jun; Li, Xueming [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing (China)

2016-11-15

In this study, an energetic material was prepared by depositing nano-Al on CuO arrays via electrophoretic deposition (EPD), which offers a feasible route for nano-Al integration. The morphology and structure of the CuO arrays and Al/CuO composites were characterized by scanning electron microscopy and X-ray diffraction. The CuO arrays were homogenously salix leaf-like structure with a width of ⁓150 to 200 nm. The energy density of Al/CuO composites was approximate to 1454.5 J/g by integrating the differential scanning calorimetry (DSC) plot and the combustion performance was recorded by a high-speed camera. Moreover, the combustion flames were violent and the whole reaction process only lasted 72.2 ms, indicating that the energy of the Al/CuO nanothermite can be released effectively.

Effect of nitrogen on the electrochemical performance of core–shell structured Si/C nanocomposites as anode materials for Li-ion batteries

International Nuclear Information System (INIS)

Tao, Hua-Chao; Huang, Mian; Fan, Li-Zhen; Qu, Xuanhui

2013-01-01

Highlights: ► N-containing core–shell structured Si/C nanocomposites are prepared via two steps. ► The N-containing Si/C nanocomposites exhibit high capacity and excellent cycling stability. ► The appropriate nitrogen has a beneficial effect on the electrochemical performance. -- Abstract: Core–shell structured Si/C nanocomposites with different nitrogen contents are prepared by in situ polymerization of aniline in the suspension of silicon nanoparticles followed by carbonization of Si/polyaniline (PANI) nanocomposites at different temperatures. The nitrogen contents of Si/C nanocomposites decrease gradually with increasing carbonization temperatures. The effect of nitrogen contents on the electrochemical performance of Si/C nanocomposites as anode materials for lithium ion batteries is investigated. It is found that the Si/C nanocomposites with 4.75 wt.% nitrogen exhibit the high specific capacity of 795 mAh g −1 after 50 cycles at a current density of 100 mA g −1 and excellent cycling stability. The appropriate nitrogen in Si/C nanocomposites plays a beneficial role in the improvement of electrochemical performance. The nitrogen in Si/C nanocomposites increases the reversible capacity, which may be due to the formation of vacancies and dangling bonds around the nitrogen sites

Thermal-spectrum recriticality energetics

International Nuclear Information System (INIS)

Schwinkendorf, K.N.

1993-12-01

Large computer codes have been created in the past to predict the energy release in hypothetical core disruptive accidents (CDA), postulated to occur in liquid metal reactors (LMR). These codes, such as SIMMER, are highly specific to LMR designs. More recent attention has focused on thermal-spectrum criticality accidents, such as for fuel storage basins and waste tanks containing fissile material. This paper resents results from recent one-dimensional kinetics simulations, performed for a recriticality accident in a thermal spectrum. Reactivity insertion rates generally are smaller than in LMR CDAs, and the energetics generally are more benign. Parametric variation of input was performed, including reactivity insertion and initial temperature

Nitrogen-enriched hierarchically porous carbons prepared from polybenzoxazine for high-performance supercapacitors.

Science.gov (United States)

Wan, Liu; Wang, Jianlong; Xie, Lijing; Sun, Yahui; Li, Kaixi

2014-09-10

Nitrogen-enriched hierarchically porous carbons (HPCs) were synthesized from a novel nitrile-functionalized benzoxazine based on benzoxazine chemistry using a soft-templating method and a potassium hydroxide (KOH) chemical activation method and used as electrode materials for supercapacitors. The textural and chemical properties could be easily tuned by adding a soft template and changing the activation temperature. The introduction of the soft-templating agent (surfactant F127) resulted in the formation of mesopores, which facilitated fast ionic diffusion and reduced the internal resistance. The micropores of HPCs were extensively developed by KOH activation to provide large electrochemical double-layer capacitance. As the activation temperature increased from 600 to 800 °C, the specific surface area of nitrogen-enriched carbons increased dramatically, micropores were enlarged, and more meso/macropores were developed, but the nitrogen and oxygen content decreased, which affected the electrochemical performance. The sample HPC-800 activated at 800 °C possesses a high specific surface area (1555.4 m(2) g(-1)), high oxygen (10.61 wt %) and nitrogen (3.64 wt %) contents, a hierarchical pore structure, a high graphitization degree, and good electrical conductivity. It shows great pseudocapacitance and the largest specific capacitance of 641.6 F g(-1) at a current density of 1 A g(-1) in a 6 mol L(-1) KOH aqueous electrolyte when measured in a three-electrode system. Furthermore, the HPC-800 electrode exhibits excellent rate capability (443.0 F g(-1) remained at 40 A g(-1)) and good cycling stability (94.3% capacitance retention over 5000 cycles).

Observations of interplanetary energetic ion enhancements near magnetic sector boundaries

International Nuclear Information System (INIS)

Briggs, P.R.; Armstrong, T.P.

1984-01-01

We have examined all energetic medium nuclei (carbon, nitrogen, and oxygen) flux increases observed all the satellites IMP 7 and IMP 8 at 1 AU during Bartels rotations 1906-1974. After removing flare-related increases, the remaining 14 ''events'' were compared to interplanetary magnetic field and solar wind parameters. We have discovered a class of flux enhancements in which the ion increases occur close to the onset of magnetic sector boundary crossings. We interpret this observation as a facilitated access to 1 AU of energetic ions from the corona or chromopshere via the magnetic sector structure. It appears that this access is more significant for medium than for lighter nuclei, ''suggesting a possible charge- or rigidity-dependent transport mechanism

Anchoring ZnO Nanoparticles in Nitrogen-Doped Graphene Sheets as a High-Performance Anode Material for Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Guanghui Yuan

2018-01-01

Full Text Available A novel binary nanocomposite, ZnO/nitrogen-doped graphene (ZnO/NG, is synthesized via a facile solution method. In this prepared ZnO/NG composite, highly-crystalline ZnO nanoparticles with a size of about 10 nm are anchored uniformly on the N-doped graphene nanosheets. Electrochemical properties of the ZnO/NG composite as anode materials are systematically investigated in lithium-ion batteries. Specifically, the ZnO/NG composite can maintain the reversible specific discharge capacity at 870 mAh g−1 after 200 cycles at 100 mA g−1. Besides the enhanced electronic conductivity provided by interlaced N-doped graphene nanosheets, the excellent lithium storage properties of the ZnO/NG composite can be due to nanosized structure of ZnO particles, shortening the Li+ diffusion distance, increasing reaction sites, and buffering the ZnO volume change during the charge/discharge process.

Nitrogen-enriched carbon with extremely high mesoporosity and tunable mesopore size for high-performance supercapacitors

Science.gov (United States)

Yang, Xiaoqing; Li, Chengfei; Fu, Ruowen

2016-07-01

As one of the most potential electrode materials for supercapacitors, nitrogen-enriched nanocarbons are still facing challenge of constructing developed mesoporosity for rapid mass transportation and tailoring their pore size for performance optimization and expanding their application scopes. Herein we develop a series of nitrogen-enriched mesoporous carbon (NMC) with extremely high mesoporosity and tunable mesopore size by a two-step method using silica gel as template. In our approach, mesopore size can be easily tailored from 4.7 to 35 nm by increasing the HF/TEOS volume ratio from 1/100 to 1/4. The NMC with mesopores of 6.2 nm presents the largest mesopore volume, surface area and mesopore ratio of 2.56 cm3 g-1, 1003 m2 g-1 and 97.7%, respectively. As a result, the highest specific capacitance of 325 F g-1 can be obtained at the current density of 0.1 A g-1, which can stay over 88% (286 F g-1) as the current density increases by 100 times (10 A g-1). This approach may open the doors for preparation of nitrogen-enriched nanocarbons with desired nanostructure for numerous applications.

Novel Method to Characterize and Model the Multiaxial Constitutive and Damage Response of Energetic Materials.

Energy Technology Data Exchange (ETDEWEB)

Kaneshige, Michael J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rabbi, Md Fazle [Univ. of Texas, El Paso, TX (United States); Kaneshige, Michael J. [Univ. of Texas, El Paso, TX (United States); Mach, Robert [Univ. of Texas, El Paso, TX (United States); Catzin, Carlos A. [Univ. of Texas, El Paso, TX (United States); Stewart, Calvin M. [Univ. of Texas, El Paso, TX (United States)

2017-12-01

Simulant polymer bonded explosives are widely used to simulate the mechanical response of real energetic materials. In this paper, the fracture resistance of a simulant polymer bo nded explosive (PBX) is experimentally investigated. The simulant is composed of 80 wt.% soda lime glass beads (SLGB) and 20 wt.% high impact Polystyrene 825 (HIPS). Brazilian disk tests are performed to characterize the tensile and compressive properties. Fracture toughness and energy tests are performed in the semi - circular bending (SCB) configuration on 80, 81, 82, and 83 wt % SLGB compositions. Digital image correlation is performed to record the surface displacements and calculate surface strains during testing. The m icromechanical behavior of ductile and brittle fracture are evaluated using digital microscopy and scanning electron microscopy of the fracture surface. It is determined that (i) the manufacturing process produces a credible simulant of PBX properties, and (ii) the SCB test measures fracture resistance with a reasonable coefficient of variation.

Nitrogen-Doped Graphene:Effects of nitrogen species on the properties of the vanadium redox flow battery

International Nuclear Information System (INIS)

Shi, Lang; Liu, Suqin; He, Zhen; Shen, Junxi

2014-01-01

Nitrogen-doped graphene nanosheets (NGS), prepared by a simple hydrothermal reaction of graphene oxide (GO) with urea as nitrogen source were studied as positive electrodes in vanadium redox flow battery (VRFB). The synthesized NGS with the nitrogen level as high as 10.12 atom% is proven to be a promising material for VRFB. The structures and electrochemical properties of the materials are investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry and electrochemical impendence spectroscopy. The results demonstrate that not only the nitrogen doping level but the nitrogen type in the NGS are significant for its catalytic activity towards the [VO] 2+ /[VO 2 ] + redox couple reaction. In more detail, among four types of nitrogen species (pyridinic-N, pyrrolic-N, quaternary-N, oxidic-N) doped into the graphene lattice, quaternary-N play mainly roles for improving the catalytic activity toward the [VO] 2+ /[VO 2 ] + couple reaction

Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics.

Science.gov (United States)

Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Jaung, Jae Yun; Kim, Yong-Hoon; Park, Sung Kyu

2015-09-28

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

Fessibility Study on Nitrogen in Explosives using X-ray Photoelectron Spectroscopy: Chemical Fertilizer

International Nuclear Information System (INIS)

Dararutana, P.

2014-01-01

It was known that an explosive is defined as a material which contains a large amount of energy stored in chemical bonds. The energetic stability of gaseous products, and hence, their generation come from the strong bond formation of carbon (mono/di)oxide and (di)nitrogen. Consequently, most commercial explosives are contained -NO 2 , -ONO 2 and/or -NHNO 2 groups which when detonated release gases like the aforementioned ones, e.g., nitroglycerin, TNT, HMX, PETN, nitrocellulose, etc. It was revealed that the elemental compositions, especially N was found in most of the explosive and fertilizer. Chemical fertilizers that used as explosive stimulants were analyzed using X-ray photoelectron spectroscopy (XPS) and scanning electron microscope coupled with energy-dispersive X-ray fluorescence spectroscopy (SEM-EDS). XPS spectra showed relatively high amount of nitrogen (N) in the various samples, especially sample #6 and #7. In addition, the elemental analysis revealed the presence of trace elements. Explosives and fertilizers have differences in specific compositions. It can be concluded that these methods seem to be used as a fingerprint examination to identify various kinds of explosives and fertilizers.

Crumpled Nitrogen-Doped Graphene for Supercapacitors with High Gravimetric and Volumetric Performances.

Science.gov (United States)

Wang, Jie; Ding, Bing; Xu, Yunling; Shen, Laifa; Dou, Hui; Zhang, Xiaogang

2015-10-14

Graphene is considered a promising electrochemical capacitors electrode material due to its high surface area and high electrical conductivity. However, restacking interactions between graphene nanosheets significantly decrease the ion-accessible surface area and impede electronic and ionic transfer. This would, in turn, severely hinder the realization of high energy density. Herein, we report a strategy for preparation of few-layer graphene material with abundant crumples and high-level nitrogen doping. The two-dimensional graphene nanosheets (CNG) feature high ion-available surface area, excellent electronic and ion transfer properties, and high packing density, permitting the CNG electrode to exhibit excellent electrochemical performance. In ionic liquid electrolyte, the CNG electrode exhibits gravimetric and volumetric capacitances of 128 F g(-1) and 98 F cm(-3), respectively, achieving gravimetric and volumetric energy densities of 56 Wh kg(-1) and 43 Wh L(-1). The preparation strategy described here provides a new approach for developing a graphene-based supercapacitor with high gravimetric and volumetric energy densities.

Compatibility study of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD) with some energetic components and inert materials

International Nuclear Information System (INIS)

Yan Qilong; Li Xiaojiang; Zhang Laying; Li Jizhen; Li Hongli; Liu Ziru

2008-01-01

The compatibility of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD) with some energetic components and inert materials of solid propellants was studied by using the pressure DSC method where, cyclotetramethylenetetranitroamine (HMX), cyclotrimethylenetrinitramine (RDX), 1,4-dinitropiperazine (DNP), 1.25/1-NC/NG mixture, lead 3-nitro-1,2,4-triazol-5-onate (NTO-Pb), aluminum powder (Al, particle size = 13.6 μm) and N-nitrodihydroxyethylaminedinitrate (DINA) were used as energetic components and polyethylene glycol (PEG), polyoxytetramethylene-co-oxyethylene (PET), addition product of hexamethylene diisocyanate and water (N-100), 2-nitrodianiline (2-NDPA), 1,3-dimethyl-1,3-diphenyl urea (C 2 ), carbon black (C.B.), aluminum oxide (Al 2 O 3 ), cupric 2,4-dihydroxy-benzoate (β-Cu), cupric adipate (AD-Cu) and lead phthalate (φ-Pb) were used as inert materials. It was concluded that the binary systems of TNAD with NTO-Pb, RDX, PET and Al powder are compatible, and systems of TNAD with DINA and HMX are slightly sensitive, and with 2-NDPA, φ-Pb, β-Cu, AD-Cu and Al 2 O 3 are sensitive, and with PEG, N-100, C 2 and C.B. are incompatible. The impact and friction sensitivity data of the TNAD and TNAD in combination with the other energetic materials under present study was also obtained, and there was no consequential affiliation between sensitivity and compatibility

Preliminary Hazard Analysis of Supercritical Fluid Separation of Energetic Materials

National Research Council Canada - National Science Library

1997-01-01

.... Army Research Laboratory (ARL) and elsewhere, particularly at the Phasex Corporation, Lawrence, MA, has demonstrated the feasibility of separating the energetic moieties by use of supercritical CO2...

Exhaustive Conversion of Inorganic Nitrogen to Nitrogen Gas Based on a Photoelectro-Chlorine Cycle Reaction and a Highly Selective Nitrogen Gas Generation Cathode.

Science.gov (United States)

Zhang, Yan; Li, Jinhua; Bai, Jing; Shen, Zhaoxi; Li, Linsen; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

2018-02-06

A novel method for the exhaustive conversion of inorganic nitrogen to nitrogen gas is proposed in this paper. The key properties of the system design included an exhaustive photoelectrochemical cycle reaction in the presence of Cl - , in which Cl· generated from oxidation of Cl - by photoholes selectively converted NH 4 + to nitrogen gas and some NO 3 - or NO 2 - . The NO 3 - or NO 2 - was finally reduced to nitrogen gas on a highly selective Pd-Cu-modified Ni foam (Pd-Cu/NF) cathode to achieve exhaustive conversion of inorganic nitrogen to nitrogen gas. The results indicated total nitrogen removal efficiencies of 30 mg L -1 inorganic nitrogen (NO 3 - , NH 4 + , NO 3 - /NH 4 + = 1:1 and NO 2 - /NO 3 - /NH 4 + = 1:1:1) in 90 min were 98.2%, 97.4%, 93.1%, and 98.4%, respectively, and the remaining nitrogen was completely removed by prolonging the reaction time. The rapid reduction of nitrate was ascribed to the capacitor characteristics of Pd-Cu/NF that promoted nitrate adsorption in the presence of an electric double layer, eliminating repulsion between the cathode and the anion. Nitrate was effectively removed with a rate constant of 0.050 min -1 , which was 33 times larger than that of Pt cathode. This system shows great potential for inorganic nitrogen treatment due to the high rate, low cost, and clean energy source.

Nitrogen-doped amorphous carbon-silicon core-shell structures for high-power supercapacitor electrodes.

Science.gov (United States)

Tali, S A Safiabadi; Soleimani-Amiri, S; Sanaee, Z; Mohajerzadeh, S

2017-02-10

We report successful deposition of nitrogen-doped amorphous carbon films to realize high-power core-shell supercapacitor electrodes. A catalyst-free method is proposed to deposit large-area stable, highly conformal and highly conductive nitrogen-doped amorphous carbon (a-C:N) films by means of a direct-current plasma enhanced chemical vapor deposition technique (DC-PECVD). This approach exploits C 2 H 2 and N 2 gases as the sources of carbon and nitrogen constituents and can be applied to various micro and nanostructures. Although as-deposited a-C:N films have a porous surface, their porosity can be significantly improved through a modification process consisting of Ni-assisted annealing and etching steps. The electrochemical analyses demonstrated the superior performance of the modified a-C:N as a supercapacitor active material, where specific capacitance densities as high as 42 F/g and 8.5 mF/cm 2 (45 F/cm 3 ) on silicon microrod arrays were achieved. Furthermore, this supercapacitor electrode showed less than 6% degradation of capacitance over 5000 cycles of a galvanostatic charge-discharge test. It also exhibited a relatively high energy density of 2.3 × 10 3  Wh/m 3 (8.3 × 10 6  J/m 3 ) and ultra-high power density of 2.6 × 10 8  W/m 3 which is among the highest reported values.

Interplay of Nitrogen-Atom Inversion and Conformational Inversion in Enantiomerization of 1H-1-Benzazepines.

Science.gov (United States)

Ramig, Keith; Subramaniam, Gopal; Karimi, Sasan; Szalda, David J; Ko, Allen; Lam, Aaron; Li, Jeffrey; Coaderaj, Ani; Cavdar, Leyla; Bogdan, Lukasz; Kwon, Kitae; Greer, Edyta M

2016-04-15

A series of 2,4-disubstituted 1H-1-benzazepines, 2a-d, 4, and 6, were studied, varying both the substituents at C2 and C4 and at the nitrogen atom. The conformational inversion (ring-flip) and nitrogen-atom inversion (N-inversion) energetics were studied by variable-temperature NMR spectroscopy and computations. The steric bulk of the nitrogen-atom substituent was found to affect both the conformation of the azepine ring and the geometry around the nitrogen atom. Also affected were the Gibbs free energy barriers for the ring-flip and the N-inversion. When the nitrogen-atom substituent was alkyl, as in 2a-c, the geometry of the nitrogen atom was nearly planar and the azepine ring was highly puckered; the result was a relatively high-energy barrier to ring-flip and a low barrier to N-inversion. Conversely, when the nitrogen-atom substituent was a hydrogen atom, as in 2d, 4, and 6, the nitrogen atom was significantly pyramidalized and the azepine ring was less puckered; the result here was a relatively high energy barrier to N-inversion and a low barrier to ring-flip. In these N-unsubstituted compounds, it was found computationally that the lowest-energy stereodynamic process was ring-flip coupled with N-inversion, as N-inversion alone had a much higher energy barrier.

Automatic liquid nitrogen feeding device

International Nuclear Information System (INIS)

Gillardeau, J.; Bona, F.; Dejachy, G.

1963-01-01

An automatic liquid nitrogen feeding device has been developed (and used) in the framework of corrosion tests realized with constantly renewed uranium hexafluoride. The issue was to feed liquid nitrogen to a large capacity metallic trap in order to condensate uranium hexafluoride at the exit of the corrosion chambers. After having studied various available devices, a feeding device has been specifically designed to be robust, secure and autonomous, as well as ensuring a high liquid nitrogen flowrate and a highly elevated feeding frequency. The device, made of standard material, has been used during 4000 hours without any problem [fr

Characterization of hydrogen, nitrogen, oxygen, carbon and sulfur in nuclear fuel (UO2) and cladding nuclear rod materials

International Nuclear Information System (INIS)

Crewe, Maria Teresa I.; Lopes, Paula Corain; Moura, Sergio C.; Sampaio, Jessica A.G.; Bustillos, Oscar V.

2011-01-01

The importance of Hydrogen, Nitrogen, Oxygen, Carbon and Sulfur gases analysis in nuclear fuels such as UO 2 , U 3 O 8 , U 3 Si 2 and in the fuel cladding such as Zircaloy, is a well known as a quality control in nuclear industry. In UO 2 pellets, the Hydrogen molecule fragilizes the metal lattice causing the material cracking. In Zircaloy material the H2 molecules cause the boiling of the cladding. Other gases like Nitrogen, Oxygen, Carbon and Sulfur affect in the lattice structure change. In this way these chemical compounds have to be measure within specify parameters, these measurement are part of the quality control of the nuclear industry. The analytical procedure has to be well established by a convention of the quality assurance. Therefore, the Oxygen, Carbon, Sulfur and Hydrogen are measured by infrared absorption (IR) and the nitrogen will be measured by thermal conductivity (TC). The gas/metal analyzer made by LECO Co. model TCHEN-600 is Hydrogen, Oxygen and Nitrogen analyzer in a variety of metals, refractory and other inorganic materials, using the principle of fusion by inert gas, infrared and thermo-coupled detector. The Carbon and Sulfur compounds are measure by LECO Co. model CS-400. A sample is first weighed and placed in a high purity graphite crucible and is casted on a stream of helium gas, enough to release the oxygen, nitrogen and hydrogen. During the fusion, the oxygen present in the sample combines with the carbon crucible to form carbon monoxide. Then, the nitrogen present in the sample is analyzed and released as molecular nitrogen and the hydrogen is released as gas. The hydrogen gas is measured by infrared absorption, and the sample gases pass through a trap of copper oxide which converts CO to CO 2 and hydrogen into water. The gases enter the cell where infrared water content is then converted making the measurement of total hydrogen present in the sample. The Hydrogen detection limits for the nuclear fuel is 1 μg/g for the Nitrogen

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.

LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

Data.gov (United States)

National Aeronautics and Space Administration — This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest canopy...

LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest...

Electrical and mechanical properties of highly elongated high density polyethylene as cryogenic insulation materials

International Nuclear Information System (INIS)

Yoshino, Katsumi; Park, Dae-Hee; Miyata, Kiyomi; Yamaoka, Hitoshi; Itoh, Minoru; Ichihara, Syouji.

1989-01-01

Electrical and mechanical properties of highly elongated high density polyethylene were investigated in the temperature range between 4.2 K and 400 K from a viewpoint of electrical insulation at low temperature and the following properties have been clarified. (1) The electrical conductivity of samples decreases with increasing draw ratio, and also decreases at cryogenic temperature. (2) Breakdown strength of highly elongated sample is similar to that of non-elongated sample. It is nearby temperature independent below 300 K but at higher temperature it falls steeply. (3) Mechanical breakdown stress and elastic modulus of high density polyethylene increase with increasing draw ratio. Their values at liquid nitrogen temperature are much higher than that at room temperature. On the other hand, strains decreases at liquid nitrogen temperature. (4) Break of the sample develops in the direction of 45deg from the direction of stress both at room temperature and at cryogenic temperature. (5) The characteristic of mechanical breakdown at liquid nitrogen temperature can be explained by a brittleness fracture process. (6) Toughness of high density polyethylene increases with increasing draw ratio until draw ratio of 5, and it decreased, and increase at higher draw ratio. However at extremely high draw ratio of 10 it again increases. These findings clearly indicate that highly elongated high density polyethylene has good electrical and mechanical properties at cryogenic temperature and can be used as the insulating materials at cryogenic temperature. (author)

Evidence against the energetic cost hypothesis for the short introns in highly expressed genes

Directory of Open Access Journals (Sweden)

Niu Deng-Ke

2008-05-01

Full Text Available Abstract Background In animals, the moss Physcomitrella patens and the pollen of Arabidopsis thaliana, highly expressed genes have shorter introns than weakly expressed genes. A popular explanation for this is selection for transcription efficiency, which includes two sub-hypotheses: to minimize the energetic cost or to minimize the time cost. Results In an individual human, different organs may differ up to hundreds of times in cell number (for example, a liver versus a hypothalamus. Considered at the individual level, a gene specifically expressed in a large organ is actually transcribed tens or hundreds of times more than a gene with a similar expression level (a measure of mRNA abundance per cell specifically expressed in a small organ. According to the energetic cost hypothesis, the former should have shorter introns than the latter. However, in humans and mice we have not found significant differences in intron length between large-tissue/organ-specific genes and small-tissue/organ-specific genes with similar expression levels. Qualitative estimation shows that the deleterious effect (that is, the energetic burden of long introns in highly expressed genes is too negligible to be efficiently selected against in mammals. Conclusion The short introns in highly expressed genes should not be attributed to energy constraint. We evaluated evidence for the time cost hypothesis and other alternatives.

Preparation of nitrogen-doped biomass-derived carbon nanofibers/graphene aerogel as a binder-free electrode for high performance supercapacitors

Science.gov (United States)

Zhang, Yimei; Wang, Fei; Zhu, Hao; Zhou, Lincheng; Zheng, Xinliang; Li, Xinghua; Chen, Zhuang; Wang, Yue; Zhang, Dandan; Pan, Duo

2017-12-01

Carbon materials derived from various biomasses have aroused forceful interest from scientific community based on their abundant resource, low cost, environment friendly and easy fabrication. Herein, the method has been developed to prepare nitrogen-doped biomass-derived carbon nanofibers/graphene aerogel (NCGA) as the binder-free electrode for supercapacitors. Ethylenediamine (EDA) is select as nitrogen source for its high nitrogen content and strong interaction with graphene oxide (GO) and cellulose nanofibers (CNFs) via hydrothermal self-assembly method to form hybrid hydrogel, and finally converts to NCGA by freeze-drying and carbonization. After carbonization the insulated CNFs converted to high conductivity carbon nanofibers. The NCGA electrode exhibits a high specific capacitance of 289 F g-1 at 5 mV s-1 and high stability of 90.5% capacitance retention ratio after 5000 cycles at 3 A g-1. This novel biomass electrode could be potential candidate for high performance supercapacitors.

Revisiting nitrogen species in covalent triazine frameworks

KAUST Repository

Osadchii, Dmitrii Yu.

2017-11-28

Covalent triazine frameworks (CTFs) are porous organic materials promising for applications in catalysis and separation due to their high stability, adjustable porosity and intrinsic nitrogen functionalities. CTFs are prepared by ionothermal trimerization of aromatic nitriles, however, multiple side reactions also occur under synthesis conditions, and their influence on the material properties is still poorly described. Here we report the systematic characterization of nitrogen in CTFs using X-ray photoelectron spectroscopy (XPS). With the use of model compounds, we could distinguish several types of nitrogen species. By combining these data with textural properties, we unravel the influence that the reaction temperature, the catalyst and the monomer structure and composition have on the properties of the resulting CTF materials.

Revisiting nitrogen species in covalent triazine frameworks

KAUST Repository

Osadchii, Dmitrii Yu.; Olivos Suarez, Alma Itzel; Bavykina, Anastasiya V.; Gascon, Jorge

2017-01-01

Covalent triazine frameworks (CTFs) are porous organic materials promising for applications in catalysis and separation due to their high stability, adjustable porosity and intrinsic nitrogen functionalities. CTFs are prepared by ionothermal trimerization of aromatic nitriles, however, multiple side reactions also occur under synthesis conditions, and their influence on the material properties is still poorly described. Here we report the systematic characterization of nitrogen in CTFs using X-ray photoelectron spectroscopy (XPS). With the use of model compounds, we could distinguish several types of nitrogen species. By combining these data with textural properties, we unravel the influence that the reaction temperature, the catalyst and the monomer structure and composition have on the properties of the resulting CTF materials.

Anisotropy of fracture toughness of austenitic high nitrogen chromium-manganese steel

International Nuclear Information System (INIS)

Balitskii, A.I.; Pokhmurskii, V.I.; Diener, M.; Magdowski, R.; Speidel, M.O.

1999-01-01

The anisotropy of mechanical properties, in particular of the fracture toughness measured by the J-integral method, is demonstrated for industrially manufactured high strength retaining rings made from the nitrogen alloyed steel 18Mn18Cr. The RT-orientation turns out to be the weakest with regard to the resistance of the material to stable crack growth. The fracture toughness results are compared with results from calorimetric measurements. Here, also an orientation dependence of the heat irradiation energy is observed, clearly showing the same ranking of specimen orientation as the toughness data suggest. (orig.)

Nitrogen-doped mesoporous carbons for high performance supercapacitors

Science.gov (United States)

Wu, Kai; Liu, Qiming

2016-08-01

The mesoporous carbons have been synthesized by using α-D(+)-Glucose, D-Glucosamine hydrochloride or their mixture as carbon precursors and mesoporous silicas (SBA-15 or MCF) as hard templates. The as-prepared products show a large pore volume (0.59-0.97 cm3 g-1), high surface areas (352.72-1152.67 m2 g-1) and rational nitrogen content (ca. 2.5-3.9 wt.%). The results of electrochemical tests demonstrate that both heteroatom doping and suitable pore structure play a decisive role in the performance of supercapacitors. The representative sample of SBA-15 replica obtained using D-Glucosamine hydrochloride only exhibits high specific capacitance (212.8 F g-1 at 0.5 A g-1) and good cycle durability (86.1% of the initial capacitance after 2000 cycles) in 6 M KOH aqueous electrolyte, which is attributed to the contribution of double layer capacitance and pseudo-capacitance. The excellent electrochemical performance makes it a promising electrode material for supercapacitors.

Mesoporous nitrogen-rich carbon materials as cathode catalysts in microbial fuel cells

KAUST Repository

Ahn, Yongtae

2014-12-01

The high cost of the catalyst material used for the oxygen reduction reaction in microbial fuel cell (MFC) cathodes is one of the factors limiting practical applications of this technology. Mesoporous nitrogen-rich carbon (MNC), prepared at different temperatures, was examined as an oxygen reduction catalyst, and compared in performance to Pt in MFCs and electrochemical cells. MNC calcined at 800 °C produced a maximum power density of 979 ± 131 mW m-2 in MFCs, which was 37% higher than that produced using MNC calined at 600 °C (715 ± 152 mW m-2), and only 14% lower than that obtained with Pt (1143 ± 54 mW m-2). The extent of COD removal and coulombic efficiencies were the same for all cathode materials. These results show that MNC could be used as an alternative to Pt in MFCs. © 2014 Elsevier B.V. All rights reserved.

Intense energetic electron flux enhancements in Mercury's magnetosphere: An integrated view with high-resolution observations from MESSENGER.

Science.gov (United States)

Baker, Daniel N; Dewey, Ryan M; Lawrence, David J; Goldsten, John O; Peplowski, Patrick N; Korth, Haje; Slavin, James A; Krimigis, Stamatios M; Anderson, Brian J; Ho, George C; McNutt, Ralph L; Raines, Jim M; Schriver, David; Solomon, Sean C

2016-03-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury has provided a wealth of new data about energetic particle phenomena. With observations from MESSENGER's Energetic Particle Spectrometer, as well as data arising from energetic electrons recorded by the X-Ray Spectrometer and Gamma-Ray and Neutron Spectrometer (GRNS) instruments, recent work greatly extends our record of the acceleration, transport, and loss of energetic electrons at Mercury. The combined data sets include measurements from a few keV up to several hundred keV in electron kinetic energy and have permitted relatively good spatial and temporal resolution for many events. We focus here on the detailed nature of energetic electron bursts measured by the GRNS system, and we place these events in the context of solar wind and magnetospheric forcing at Mercury. Our examination of data at high temporal resolution (10 ms) during the period March 2013 through October 2014 supports strongly the view that energetic electrons are accelerated in the near-tail region of Mercury's magnetosphere and are subsequently "injected" onto closed magnetic field lines on the planetary nightside. The electrons populate the plasma sheet and drift rapidly eastward toward the dawn and prenoon sectors, at times executing multiple complete drifts around the planet to form "quasi-trapped" populations.

Improving the capacity of lithium-sulfur batteries by tailoring the polysulfide adsorption efficiency of hierarchical oxygen/nitrogen-functionalized carbon host materials.

Science.gov (United States)

Schneider, Artur; Janek, Jürgen; Brezesinski, Torsten

2017-03-22

The use of monolithic carbons with structural hierarchy and varying amounts of nitrogen and oxygen functionalities as sulfur host materials in high-loading lithium-sulfur cells is reported. The primary focus is on the strength of the polysulfide/carbon interaction with the goal of assessing the effect of (surface) dopant concentration on cathode performance. The adsorption capacity - which is a measure of the interaction strength between the intermediate lithium polysulfide species and the carbon - was found to scale almost linearly with the nitrogen level. Likewise, the discharge capacity of lithium-sulfur cells increased linearly. This positive correlation can be explained by the favorable effect of nitrogen on both the chemical and electronic properties of the carbon host. The incorporation of additional oxygen-containing surface groups into highly nitrogen-functionalized carbon helped to further enhance the polysulfide adsorption efficiency, and therefore the reversible cell capacity. Overall, the areal capacity could be increased by almost 70% to around 3 mA h cm -2 . We believe that the design parameters described here provide a blueprint for future carbon-based nanocomposites for high-performance lithium-sulfur cells.

Energetic balance and air pollutant emissions estimates in the Aburra Valley, 1999: A preliminary approximation

International Nuclear Information System (INIS)

Molina Perez; Francisco; Saavedra Duque, Marcela; Obregon Cardona Mauricio

2003-01-01

Based on the application of Material Fluxes Analysis, this paper presents the composition of the energetic basket in Valle de Aburra during 1999 and the atmospheric emissions caused by the consumption of those energetic materials. Basically, it was found that the daily energetic consumption of the system was 43,2 Tcal that generated 716 ton. by day of atmospheric contaminants as an output. The results show that the main energetic materials that participate in the global metabolism of the system, was those consumed in the transportation sector (gasoline and diesel). Therefore transportation sector contributes with the principal load of contaminants represented by carbon monoxide that overtake the 77,6% of the whole emissions

Potential Energy Surfaces and Dynamics of High Energy Species

Science.gov (United States)

2009-04-13

explored include ionic liquids and a range of high-nitrogen content and nitrogen-oxygen content species. Polyhedral oligomeric silisesquioxanes are...Approved for Public Release 13. SUPPLEMENTARY NOTES 14. ABSTRACT Several papers on ionic liquids have been published or submitted as a result of this...in energetic ionic liquids . These are variously substituted triazolium, tertazolium, and pentazolium cations. The heats of formation of all species

Few-layer MoS2 as nitrogen protective barrier

Science.gov (United States)

Akbali, B.; Yanilmaz, A.; Tomak, A.; Tongay, S.; Çelebi, C.; Sahin, H.

2017-10-01

We report experimental and theoretical investigations of the observed barrier behavior of few-layer MoS2 against nitrogenation. Owing to its low-strength shearing, low friction coefficient, and high lubricity, MoS2 exhibits the demeanor of a natural N-resistant coating material. Raman spectroscopy is done to determine the coating capability of MoS2 on graphene. Surface morphology of our MoS2/graphene heterostructure is characterized by using optical microscopy, scanning electron microscopy, and atomic force microscopy. In addition, density functional theory-based calculations are performed to understand the energy barrier performance of MoS2 against nitrogenation. The penetration of nitrogen atoms through a defect-free MoS2 layer is prevented by a very high vertical diffusion barrier, indicating that MoS2 can serve as a protective layer for the nitrogenation of graphene. Our experimental and theoretical results show that MoS2 material can be used both as an efficient nanocoating material and as a nanoscale mask for selective nitrogenation of graphene layer.

Formation, Energetics, and Electronic Properties of Graphene Monolayer and Bilayer Doped with Heteroatoms

Directory of Open Access Journals (Sweden)

Yoshitaka Fujimoto

2015-01-01

Full Text Available Doping with heteroatoms is one of the most effective methods to tailor the electronic properties of carbon nanomaterials such as graphene and carbon nanotubes, and such nanomaterials doped with heteroatom dopants might therefore provide not only new physical and chemical properties but also novel nanoelectronics/optoelectronics device applications. The boron and nitrogen are neighboring elements to carbon in the periodic table, and they are considered to be good dopants for carbon nanomaterials. We here review the recent work of boron and nitrogen doping effects into graphene monolayer as well as bilayer on the basis of the first-principles electronic structure calculations in the framework of the density-functional theory. We show the energetics and the electronic properties of boron and nitrogen defects in graphene monolayer and bilayer. As for the nitrogen doping, we further discuss the stabilities, the growth processes, and the electronic properties associated with the plausible nitrogen defect formation in graphene which is suggested by experimental observations.

Hydrothermal synthesis of highly nitrogen-doped few-layer graphene via solid–gas reaction

International Nuclear Information System (INIS)

Liang, Xianqing; Zhong, Jun; Shi, Yalin; Guo, Jin; Huang, Guolong; Hong, Caihao; Zhao, Yidong

2015-01-01

Highlights: • A novel approach to synthesis of N-doped few-layer graphene has been developed. • The high doping levels of N in products are achieved. • XPS and XANES results reveal a thermal transformation of N bonding configurations. • The developed method is cost-effective and eco-friendly. - Abstract: Nitrogen-doped (N-doped) graphene sheets with high doping concentration were facilely synthesized through solid–gas reaction of graphene oxide (GO) with ammonia vapor in a self-designed hydrothermal system. The morphology, surface chemistry and electronic structure of N-doped graphene sheets were investigated by TEM, AFM, XRD, XPS, XANES and Raman characterizations. Upon hydrothermal treatment, up to 13.22 at% of nitrogen could be introduced into the crumpled few-layer graphene sheets. Both XPS and XANES analysis reveal that the reaction between oxygen functional groups in GO and ammonia vapor produces amide and amine species in hydrothermally treated GO (HTGO). Subsequent thermal annealing of the resultant HTGO introduces a gradual transformation of nitrogen bonding configurations in graphene sheets from amine N to pyridinic and graphitic N with the increase of annealing temperature. This study provides a simple but cost-effective and eco-friendly method to prepare N-doped graphene materials in large-scale for potential applications

A highly efficient electrocatalyst for oxygen reduction reaction: phosphorus and nitrogen co-doped hierarchically ordered porous carbon derived from an iron-functionalized polymer

Science.gov (United States)

Deng, Chengwei; Zhong, Hexiang; Li, Xianfeng; Yao, Lan; Zhang, Huamin

2016-01-01

Heteroatom-doped carbon materials have shown respectable activity for the oxygen reduction reaction (ORR) in alkaline media. However, the performances of these materials are not satisfactory for energy conversion devices, such as fuel cells. Here, we demonstrate a new type of phosphorus and nitrogen co-doped hierarchically ordered porous carbon (PNHOPC) derived from an iron-functionalized mesoporous polymer through an evaporation-induced self-assembly process that simultaneously combines the carbonization and nitrogen doping processes. The soft template and the nitrogen doping process facilitate the formation of the hierarchically ordered structure for the PNHOPC. The catalyst possesses a large surface area (1118 cm2 g-1) and a pore volume of 1.14 cm3 g-1. Notably, it exhibits excellent ORR catalytic performance, superior stability and methanol tolerance in acidic electrolytes, thus making the catalyst promising for fuel cells. The correlations between the unique pore structure and the nitrogen and phosphorus configuration of the catalysts with high catalytic activity are thoroughly investigated.Heteroatom-doped carbon materials have shown respectable activity for the oxygen reduction reaction (ORR) in alkaline media. However, the performances of these materials are not satisfactory for energy conversion devices, such as fuel cells. Here, we demonstrate a new type of phosphorus and nitrogen co-doped hierarchically ordered porous carbon (PNHOPC) derived from an iron-functionalized mesoporous polymer through an evaporation-induced self-assembly process that simultaneously combines the carbonization and nitrogen doping processes. The soft template and the nitrogen doping process facilitate the formation of the hierarchically ordered structure for the PNHOPC. The catalyst possesses a large surface area (1118 cm2 g-1) and a pore volume of 1.14 cm3 g-1. Notably, it exhibits excellent ORR catalytic performance, superior stability and methanol tolerance in acidic

Use of 15N dilution method for screening soybean lines with high yield and high nitrogen fixation ability

International Nuclear Information System (INIS)

Li Haixian; Li Xinmin; Danso, S.K.A.

1998-01-01

15 N dilution method was used for screening soybean lines with high nitrogen fixation ability. Screened lines 1005, 8502, 2096, 943, 1454 and Dongnong-42 have high nitrogen fixation ability with their % Ndfa of about 70%. 1454 and 1555 are both high yield and high nitrogen fixation lines. The ability of nitrogen fixation was not related to the yield, but related to maturing time. The cultivars with different maturing time have different levels of nitrogen fixation ability. The longer the maturing period is, the greater the ability of nitrogen fixation it has. There were ten cultivars or lines used in the test of 1992 and 1994. Although the weather condition were greatly different between the two years the results of seven cultivars or lines were the same, indicating that nitrogen fixation ability of the soybean is stable with years. Using 15 N dilution method to estimate nitrogen fixation ability of soybean is reliable, however, the % Ndfa of lines 8502 and 2096 increased by 19% in 1994, a rainy year, indicating that a change in % Ndfa with a few varieties maybe caused by weather

A high Tc superconducting liquid nitrogen level sensor

International Nuclear Information System (INIS)

Jin, J. X.; Liu, H. K.; Dou, S. X.; Grantham, C.; Beer, J.

1996-01-01

Full text: The dramatic resistance change in the superconducting-normal transition temperature range enables a high T c superconductor to be considered for designing a liquid nitrogen level sensor. A (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10+x Ag clad superconducting wire is selected and tested as a continuous liquid nitrogen level sensor to investigate the possibility for this application. The (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10+x Ag clad superconducting wire has approximately 110 K critical temperature, with more flexible and stable properties compared with bulk shape ceramic high T c superconductors. The voltage drops across the sensor are tested with different immersion lengths in liquid nitrogen. The accuracy of the HTS sensor is analysed with its dR/dT in the superconducting-normal transition range. The voltage signal is sensitive to liquid nitrogen level change, and this signal can be optimized by controlling the transport current. The problems of the Ag clad superconductor are that the Ag sheath thermal conductivity is very high, and the sensor normal resistance is low. These are the main disadvantages for using such a wire as a continuous level sensor. However, a satisfactory accuracy can be achieved by control of the transport current. A different configuration of the wire sensor is also designed to avoid this thermal influence

Strengthening Hadfield steel welds by nitrogen alloying

International Nuclear Information System (INIS)

Efstathiou, C.; Sehitoglu, H.

2009-01-01

Strengthening Hadfield steel weld repairs by introducing nitrogen into the weld region was proven to be feasible via two welding techniques. The first technique required a pure Hadfield steel filler material to be diffusion treated in a high pressure nitrogen gas environment, and subsequently used during tungsten inert gas welding with a pure argon shielding gas. The second technique used a Hadfield steel filler material, and a 10% nitrogen containing argon shielding gas during tungsten inert gas welding. Both techniques increased the yield strength, the hardening rate, and the ultimate strength of the weld region. Using optical microscopy, scanning electron microscopy, and Auger spectroscopy, we determined that the increased strength of the weld region resulted from a combination of nitrogen alloying and microstructural refinement

Creation of high density ensembles of nitrogen-vacancy centers in nitrogen-rich type Ib nanodiamonds

International Nuclear Information System (INIS)

Su, Long-Jyun; Fang, Chia-Yi; Chang, Yu-Tang; Chang, Huan-Cheng; Chen, Kuan-Ming; Yu, Yueh-Chung; Hsu, Jui-Hung

2013-01-01

This work explores the possibility of increasing the density of negatively charged nitrogen-vacancy centers ([NV − ]) in nanodiamonds using nitrogen-rich type Ib diamond powders as the starting material. The nanodiamonds (10–100 nm in diameter) were prepared by ball milling of microdiamonds, in which the density of neutral and atomically dispersed nitrogen atoms ([N 0 ]) was measured by diffuse reflectance infrared Fourier transform spectroscopy. A systematic measurement of the fluorescence intensities and lifetimes of the crushed monocrystalline diamonds as a function of [N 0 ] indicated that [NV − ] increases nearly linearly with [N 0 ] at 100–200 ppm. The trend, however, failed to continue for nanodiamonds with higher [N 0 ] (up to 390 ppm) but poorer crystallinity. We attribute the result to a combined effect of fluorescence quenching as well as the lower conversion efficiency of vacancies to NV − due to the presence of more impurities and defects in these as-grown diamond crystallites. The principles and practice of fabricating brighter and smaller fluorescent nanodiamonds are discussed. (paper)

Creation of high density ensembles of nitrogen-vacancy centers in nitrogen-rich type Ib nanodiamonds.

Science.gov (United States)

Su, Long-Jyun; Fang, Chia-Yi; Chang, Yu-Tang; Chen, Kuan-Ming; Yu, Yueh-Chung; Hsu, Jui-Hung; Chang, Huan-Cheng

2013-08-09

This work explores the possibility of increasing the density of negatively charged nitrogen-vacancy centers ([NV(-)]) in nanodiamonds using nitrogen-rich type Ib diamond powders as the starting material. The nanodiamonds (10-100 nm in diameter) were prepared by ball milling of microdiamonds, in which the density of neutral and atomically dispersed nitrogen atoms ([N(0)]) was measured by diffuse reflectance infrared Fourier transform spectroscopy. A systematic measurement of the fluorescence intensities and lifetimes of the crushed monocrystalline diamonds as a function of [N(0)] indicated that [NV(-)] increases nearly linearly with [N(0)] at 100-200 ppm. The trend, however, failed to continue for nanodiamonds with higher [N(0)] (up to 390 ppm) but poorer crystallinity. We attribute the result to a combined effect of fluorescence quenching as well as the lower conversion efficiency of vacancies to NV(-) due to the presence of more impurities and defects in these as-grown diamond crystallites. The principles and practice of fabricating brighter and smaller fluorescent nanodiamonds are discussed.

Use of 15N enriched plant material for labelling of soil nitrogen in legume dinitrogen fixation experiments

International Nuclear Information System (INIS)

Jensen, E.S.

1989-06-01

The soil nitrogen in a field plot was labelled with nitrogen-15 (15N) by incorporating labelled plant material derived from previous experiments. The plot was used the following 3 years for determination of the amount of N2 fixed by different leguminous plants. The atom % 15N excess in grains of cereals grown as reference crops was 0.20, 0.05 and 0.03 in the 3 years, respectively. In the first year the level of enrichment was adequate for estimating symbiotic nitrogen fixation. In the second and third year lack of precision in determination of the 15N/14N ratios of legume N, may have caused an error in estimates of nitrogen fixation. About 23% of the labelled N was taken up by plants during the 3 years of cropping; after 4 years about 44% of the labelled N was found still to be present in the top soil. The labelling of the soil nitrogen with organic bound 15N, compared to adding mineral 15N at sowing, is advantageous because the labelled N is released by mineralization so that the enrichment of the plant available soil N pool become more uniform during the growth season; and high levels of mineral N, which may depress the fixation process, is avoided. (author) 7 tabs., 1 ill., 30 refs

High-resolution transmission electron microscopy and energetics of flattened carbon nonoshells

International Nuclear Information System (INIS)

Bourgeois, L.N.; Bursill, L.A.

1998-01-01

When examined under a high-resolution transmission electron microscope, carbon soot produced alongside buckytubes in an arc-discharge is found to contain a small percentage of flattened carbon shells. These objects are shown to be small graphite flakes which eliminated their dangling bonds by terminating their edges with highly curved junctions. Ideal models for these structures are presented, and their energy estimated. The calculations show that the establishment of highly curved junctions is energetically favourable for a graphite flake in an inert atmosphere. Flattened shells also appear more stable than their 'inflated' counterparts (fullerene 'onions' and buckytubes) when the shell dimensions obey specific criteria.(authors)

Bubble formation upon crystallization of high nitrogen iron base alloys

International Nuclear Information System (INIS)

Svyazhin, A.G.; Sivka, E.; Skuza, Z.

2000-01-01

A study is made into the conditions of nitrogen bubble formation during crystallization of unalloyed iron, alloys of Fe-O, Fe-O-S systems, steels 1Kh13, 0Kh18N9 and a two-phase Fe-11%Cr-1%Mo-0.2%V steel. It is revealed that the amount of bubbles in a high nitrogen steel casting increases with a degree of nitrogen supersaturation and decreases with a cooling rate growth and with a rise of surfactant concentration in the metal. In sound castings a nitrogen content can be increased due to a cooling rate growth, nitrogen dilution with inert gas, an increase of nitrogen pressure during crystallization as well as due to the introduction of such surfactants as sulphur, selenium, tellurium, tin [ru

Determination of nitrogen in UO2 pellets by hot extraction-TCD method without using flux material and evaluation of associated measurement uncertainties

International Nuclear Information System (INIS)

Begum, Zahida; Balaji Rao, Y.; Subba Rao, Y.

2015-01-01

Presence of non metallic impurity elements like nitrogen above the specified limit of 75 ppm (max.) in fuel pellets affects the sintered density of fuel and also effect the Zircaloy fuel clad by forming brittle nitride phase. Hence, estimation of nitrogen plays an important role in qualifying the fuel material. Conventionally, Kjeldahl steam distillation followed by UV-Visible Spectro-photometric method has been widely employed for the estimation of nitrogen in UO 2 pellets. However, inherent chemical treatment processes causes the blank variations and provides the scope for uncertainty in measurements apart from being time consuming method. This makes Kjeldahl method as an un-attractive choice for any industrial lab where high analytical loads usually exist to meet the production targets and also where urgency for quick analytical feedback is an issue. In view of this, a simple, rapid and reliable method using A LECO Model TN- 600 Nitrogen analyzer based on Hot Extraction (HT) without adding any flux material followed by Thermal Conductivity Detection (TCD) has been developed for routine analysis. Several flux materials like Pt or Ni are used to bring down the temperature of extraction due to formation of stable uranium nitrides and temperatures of 2500°C is maintained for quantitative extraction. However usage of flux materials leads to several practical problems in analysis like deposition of uranium carbide dust onto the upper electrode requiring tedious cleaning and even sometimes causing the breakage of crucibles during the analysis. Thus an attempt has been made to increase the temperatures closer to 3000°C without using flux. Working temperature of 2900°C was arrived by plotting quantity of nitrogen extracted with temperature of extraction and flattening of plot took place at 2900°C

Nitrogen in highly crystalline carbon nanotubes

International Nuclear Information System (INIS)

Ducati, C; Koziol, K; Stavrinadis, A; Friedrichs, S; Windle, A H; Midgley, P A

2006-01-01

Multiwall carbon nanotubes (MWCNTs) with an unprecedented degree of internal order were synthesised by chemical vapour deposition (CVD) adding a nitrogen-containing compound to the hydrocarbon feedstock. Ferrocene was used as the metal catalyst precursor. The remarkable crystallinity of these nanotubes lies both in the isochirality and in the crystallographic register of their walls, as demonstrated by electron diffraction and high resolution electron microscopy experiments. High resolution transmission electron microscopy analysis shows that the walls of the nanotubes consist of truncated stacked cones, instead of perfect cylinders, with a range of apex angles that appears to be related to the nitrogen concentration in the synthesis process. The structure of armchair, zigzag and chiral nanotubes is modelled and discussed in terms of density of topological defects, providing an interesting comparison with our microscopy experiments. A growth mechanism based on the interplay of base- and tip-growth is proposed to account for our experimental observations

Flexible, lightweight and paper-like supercapacitors assembled from nitrogen-doped multi-dimensional carbon materials

DEFF Research Database (Denmark)

Cao, Xianyi; Duus, Jens Øllgaard; Chi, Qijin

2017-01-01

hydrophilicity. In this work, a facile approach is developed to prepare nitrogen-doped carbon based flexible and free-standing paper electrodes {N3CPs) built from three types of representative carbon materials in different dimensions {OD: carbon black nanoparticles (CBNPs); 10: carbon nanotubes {CNTs); 20: GRSs......Flexible supercapacitors have shown great potential to fulfill the increasing demand on wearable, miniature, lightweight, thin and highly efficient power supply systems for advanced portable electronics. Owing to its superior supercapacitive performances as well as high chemical stability...... and excellent mechanical flexibility, graphene {GR} based flexible supercapacitors have received much research attention in recent years. However, GR-based supercapacitors often suffer from GR restacking leading to capacitance attenuation. Therefore, some macromolecules, polymers and zero...

Total mineral material, acidity, sulphur, and nitrogen in rain and snow at Kentville, Nova Scotia

Energy Technology Data Exchange (ETDEWEB)

Herman, F A; Gorham, E

1957-01-01

Analyses of total ash, sulphur, ph, ammonia, and nitrate nitrogen have been made on 23 monthly precipitation samples and 17 individual snow samples collected between June 1952 and May 1954 at Kentville, Nova Scotia, in a predominantly agricultural area. Mean annual supply of total mineral ash was 95 kg/ha, of sulphur 9.1 hg/ha, of ammonia nitrogen 2.8 kg/ha, and of nitrate nitrogen 1.1 kg/ha. Average pH was 5.7, and rains more acid than this exhibited higher levels of both nitrate and sulphur, and a marked correlation between the latter and ammonia. Snow samples had much lower concentrations of ash, sulphur, and nitrogen than rain samples collected in the same months, which may perhaps indicate a lower efficiency of snow flakes in removing materials from the atmosphere.

Biomass-Derived Oxygen and Nitrogen Co-Doped Porous Carbon with Hierarchical Architecture as Sulfur Hosts for High-Performance Lithium/Sulfur Batteries

Directory of Open Access Journals (Sweden)

Yan Zhao

2017-11-01

Full Text Available In this work, a facile strategy to synthesize oxygen and nitrogen co-doped porous carbon (ONPC is reported by one-step pyrolysis of waste coffee grounds. As-prepared ONPC possesses highly rich micro/mesopores as well as abundant oxygen and nitrogen co-doping, which is applied to sulfur hosts as lithium/sulfur batteries’ appropriate cathodes. In battery testing, the sulfur/oxygen and nitrogen co-doped porous carbon (S/ONPC composite materials reveal a high initial capacity of 1150 mAh·g−1 as well as a reversible capacity of 613 mAh·g−1 after the 100th cycle at 0.2 C. Furthermore, when current density increases to 1 C, a discharge capacity of 331 mAh·g−1 is still attainable. Due to the hierarchical porous framework and oxygen/nitrogen co-doping, the S/ONPC composite exhibits a high utilization of sulfur and good electrochemical performance via the immobilization of the polysulfides through strong chemical binding.

Solar cycle variations of the energetic H/He intensity ratio at high heliolatitudes and in the ecliptic plane

Directory of Open Access Journals (Sweden)

D. Lario

Full Text Available We study the variability of the heliospheric energetic proton-to-helium abundance ratios during different phases of the solar cycle. We use energetic particle, solar wind, and magnetic field data from the Ulysses, ACE and IMP-8 spacecraft to compare the H/He intensity ratio at high heliographic latitudes and in the ecliptic plane. During the first out-of-ecliptic excursion of Ulysses (1992–1996, the HI-SCALE instrument measured corotating energetic particle intensity enhancements characterized by low values (< 10 of the 0.5–1.0 MeV nucleon^-1 H/He intensity ratio. During the second out-of-ecliptic excursion of Ulysses (1999–2002, the more frequent occurrence of solar energetic particle events resulted in almost continuously high (< 20 values of the H/He ratio, even at the highest heliolatitudes reached by Ulysses. Comparison with in-ecliptic measurements from an identical instrument on the ACE spacecraft showed similar H/He values at ACE and Ulysses, suggesting a remarkable uniformity of energetic particle intensities in the solar maximum heliosphere at high heliolatitudes and in the ecliptic plane. In-ecliptic observations of the H/He intensity ratio from the IMP-8 spacecraft show variations between solar maximum and solar minimum similar to those observed by Ulysses at high heliographic latitudes. We suggest that the variation of the H/He intensity ratio throughout the solar cycle is due to the different level of transient solar activity, as well as the different structure and duration that corotating solar wind structures have under solar maximum and solar minimum conditions. During solar minimum, the interactions between the two different types of solar wind streams (slow vs. fast are strong and long-lasting, allowing for a continuous and efficient acceleration of interstellar pickup He +. During solar maximum, transient events of solar origin (characterized by high values of the H/He ratio are able to globally

Effect of nitrogen doping of graphene oxide on hydrogen and hydroxyl adsorption

Energy Technology Data Exchange (ETDEWEB)

Min, Byeong June; Jeong, Hae Kyung [Daegu University, Kyungsan (Korea, Republic of)

2014-05-15

We investigate how nitrogen-doping affects the hydrogen (H) and the hydroxyl (OH) adsorption on graphene oxide (GO) and on nitrogen-doped GO (NGO) via pseudopotential plane wave density functional calculations within the local spin density approximation. We find that the nitrogen doping brings about drastic changes in the hydrogen and the hydroxyl adsorption energetics, but its effects depend sensitively on the nitrogen configuration in NGO. The H and the OH adsorption energies are comparable only for pyrrolic NGO. In GO and quarternary NGO, the H adsorption energy is greater than the OH adsorption energy while the trend is reversed in pyridinic NGO. Also, the OH adsorption process is less affected by nitrogen-doping than the H adsorption is.

Porous Hierarchical Nitrogen-doped Carbon Coated ZnFe_2O_4 Composites as High Performance Anode Materials for Lithium Ion Batteries

International Nuclear Information System (INIS)

Yue, Hongyun; Wang, Qiuxian; Shi, Zhenpu; Ma, Chao; Ding, Yanmin; Huo, Ningning; Zhang, Jun; Yang, Shuting

2015-01-01

Porous hierarchical and nitrogen-doped carbon coated ZnFe_2O_4 (ZnFe_2O_4@NC) was obtained by combustion method and unique carbon coating technology. Gum Arabic was firstly introduced in the carbon coating process as an additive, which played an important role to control the uniformity of carbon coating layer. The nitrogen-doped carbon layer was obtained through the pyrolysis of glycine. The elemental composition and content of the nitrogen-doped carbon in composites were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and thermal gravimetric analysis (TGA). The galvanostatic charge/discharge cycling was used to test the electrochemical performance of ZnFe_2O_4@NC and pure ZnFe_2O_4. The sub-micro size ZnFe_2O_4@NC with unique porous structure showed an excellent electrochemical performance as an anode material, which was higher than that of pure ZnFe_2O_4. ZnFe_2O_4@NC could maintain the specific discharge capacity of 1477 mAh g"−"1 at 0.1 A g"−"1 after 100 cycles and 705 mAh g"−"1 at 1 A g"−"1 after 1000 cycles, respectively.

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.

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

International Nuclear Information System (INIS)

Bilek, M.M.M.; Newton-McGee, K.; McKenzie, D.R.; McCulloch, D.G.

2006-01-01

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

An Overview of Modeling Middle Atmospheric Odd Nitrogen

Science.gov (United States)

Jackman, Charles H.; Kawa, S. Randolph; Einaudi, Franco (Technical Monitor)

2001-01-01

Odd nitrogen (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, and BrONO2) constituents are important components in the control of middle atmospheric ozone. Several processes lead to the production of odd nitrogen (NO(sub y)) in the middle atmosphere (stratosphere and mesosphere) including the oxidation of nitrous oxide (N2O), lightning, downflux from the thermosphere, and energetic charged particles (e.g., galactic cosmic rays, solar proton events, and energetic electron precipitation). The dominant production mechanism of NO(sub y) in the stratosphere is N2O oxidation, although other processes contribute. Mesospheric NO(sub y) is influenced by N2O oxidation, downflux from the thermosphere, and energetic charged particles. NO(sub y) is destroyed in the middle atmosphere primarily via two processes: 1) dissociation of NO to form N and O followed by N + NO yielding N2 + O to reform even nitrogen; and 2) transport to the troposphere where HNO3 can be rapidly scavenged in water droplets and rained out of the atmosphere. There are fairly significant differences among global models that predict NO(sub y). NO(sub y) has a fairly long lifetime in the stratosphere (months to years), thus disparate transport in the models probably contributes to many of these differences. Satellite and aircraft measurement provide modeling tests of the various components of NO(sub y). Although some recent reaction rate measurements have led to improvements in model/measurement agreement, significant differences do remain. This presentation will provide an overview of several proposed sources and sinks of NO(sub y) and their regions of importance. Multi-dimensional modeling results for NO(sub y) and its components with comparisons to observations will also be presented.

All-Nitrogen Compounds as High Energy Density Materials

National Research Council Canada - National Science Library

Baum, Kurt; Willer, Rodney L; Bottaro, Jeffrey; Petrie, Mark; Penwell, Paul; Dodge, Allen; Malhotra, Ripu

2005-01-01

.... Enhanced dissolving power, density and compatibilities with a wide range of propellant ingredients make ionic liquids a very attractive class of materials for advanced state-of-the-art propulsion systems...

Progress Towards a Benchtop Energetics Capability (BRIEFING CHARTS)

National Research Council Canada - National Science Library

Fajardo, Mario E; Lewis, William K

2006-01-01

The incorporation of nanometric (sub-micron size) metal fuel and oxidizer particles into energetic materials is a promising approach to increasing significantly the systems-level performance of munitions...

Pomelo peels-derived porous activated carbon microsheets dual-doped with nitrogen and phosphorus for high performance electrochemical capacitors

Science.gov (United States)

Wang, Zhen; Tan, Yongtao; Yang, Yunlong; Zhao, Xiaoning; Liu, Ying; Niu, Lengyuan; Tichnell, Brandon; Kong, Lingbin; Kang, Long; Liu, Zhen; Ran, Fen

2018-02-01

In this work, biomass pomelo peel is used to fabricate the porous activated carbon microsheets, and diammonium hydrogen phosphate (DHP) is employed to dual-dope carbon with nitrogen and phosphorus elements. With the benefit of DHP inducement and dual-doping of nitrogen and phosphorus, the prepared carbon material has a higher carbon yield, and exhibits higher specific surface area (about 807.7 m2/g), and larger pore volume (about 0.4378 cm3/g) with hierarchically structure of interconnected thin microsheets compared to the pristine carbon. The material exhibits not only high specific capacitance (240 F/g at 0.5 A/g), but also superior cycling performance (approximately 100% of capacitance retention after 10,000 cycles at 2 A/g) in 2 M KOH aqueous electrolyte. Furthermore, the assembled symmetric electrochemical capacitor in 1 M Na2SO4 aqueous electrolyte exhibits a high energy density of 11.7 Wh/kg at a power density of 160 W/kg.

Nitrogen-enriched bituminous coal-based active carbons as materials for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

R. Pietrzak; K. Jurewicz; P. Nowicki; K. Babel; H. Wachowska [A. Mickiewicz University, Poznan (Poland). Laboratory of Coal Chemistry and Technology

2010-11-15

The paper presents the results of a study on obtaining N-enriched active carbons from bituminous coal and on testing its use as an electrode material in supercapacitors. The coal was carbonised, activated with KOH and ammoxidised by a mixture of ammonia and air at the ratio 1:3 at 300{sup o}C or 350{sup o}C, at different stages of the production, that is, at those of precursor, carbonisate, and active carbon. The products were microporous N-enriched active carbon samples of well-developed surface area reaching from 1577 to 2510 m{sup 2}/g and containing 1.0 to 8.5 wt% of nitrogen. The XPS measurements have shown that in the active carbons enriched in nitrogen at the stage of precursor and at the stage of carbonisate, the dominant nitrogen species are the N-5 groups, while in the samples ammoxidised at the last stage of the treatment the dominant nitrogen species are the surface groups of imines and/or nitriles, probably accompanied by amines and amides. The paper reports the results of a comprehensive study of the effect of the structure and chemical composition of a series of active carbon samples of different properties on their capacity performance in water solutions of H{sub 2}SO{sub 4} or KOH, with the behaviour of positive and negative electrodes analysed separately. 33 refs., 7 figs., 8 tabs.

Energetics of dislocation transformations in hcp metals

International Nuclear Information System (INIS)

Wu, Zhaoxuan; Yin, Binglun; Curtin, W.A.

2016-01-01

Dislocation core structures of hcp metals are highly complex and differ significantly among the hcp family. Some dislocations undergo unconventional transformations that have significant effects on the material plastic flow. Here, the energetics of dislocation dissociations are analyzed in a general anisotropic linear elastic theory framework for transformations in which changes in the partial Burgers vectors are small. Quantitative analyses on various transformations are made using DFT-computed stacking fault energies and partial Burgers vectors. Specifically, possible transformations of the mixed, edge, and screw 〈c+a〉 and screw 〈a〉 dislocations in 6 hcp metals (Mg, Ti, Zr, Re, Zn, Cd) are studied. Climb dissociation of mixed or edge 〈c+a〉 dislocations to the Basal plane is energetically favorable in all 6 metals and thus only limited by thermal activation. The 〈c+a〉 screw dislocation is energetically preferable on Pyramidal I for Ti, Zr, and Re, and on Pyramidal II for Zn and Cd. In Mg, the energy difference between screw 〈c+a〉 on Pyramidal I and II planes is small, suggesting relatively easy cross-slip. For the screw 〈a〉, Basal dissociation is energetically favorable in Mg, Re, Zn and Cd, while Prism dissociation is strongly favorable in Ti and Zr. Only Ti, Zr and Re show a metastable state for dissociation on the Prism plane, and the energy difference between screw 〈a〉 on the Prism and Pyramidal I planes is relatively small in all systems, suggesting relatively easy cross-slip of 〈a〉 in Ti and Zr. The elastic analysis thus provides a single framework able to capture the controlling energetics for different dissociations and slip systems in hcp metals. When the calculated energy differences are very small, the results point to the need for detailed modeling of the atomistic core structure. Moreover, the analyses rationalize broad experimental observations on dominant slip systems and dislocation behaviours, and provide

Hepatic mitochondrial energetics during catch-up fat with high-fat diets rich in lard or safflower oil.

Science.gov (United States)

Crescenzo, Raffaella; Bianco, Francesca; Falcone, Italia; Tsalouhidou, Sofia; Yepuri, Gayathri; Mougios, Vassilis; Dulloo, Abdul G; Liverini, Giovanna; Iossa, Susanna

2012-09-01

We have investigated whether altered hepatic mitochondrial energetics could explain the differential effects of high-fat diets with low or high ω6 polyunsaturated fatty acid content (lard vs. safflower oil) on the efficiency of body fat recovery (catch-up fat) during refeeding after caloric restriction. After 2 weeks of caloric restriction, rats were isocalorically refed with a low-fat diet (LF) or high-fat diets made from either lard or safflower oil for 1 week, and energy balance and body composition changes were assessed. Hepatic mitochondrial energetics were determined from measurements of liver mitochondrial mass, respiratory capacities, and proton leak. Compared to rats refed the LF, the groups refed high-fat diets showed lower energy expenditure and increased efficiency of fat gain; these differences were less marked with high-safflower oil than with high-lard diet. The increase in efficiency of catch-up fat by the high-fat diets could not be attributed to differences in liver mitochondrial activity. By contrast, the lower fat gain with high-safflower oil than with high-lard diet is accompanied by higher mitochondrial proton leak and increased proportion of arachidonic acid in mitochondrial membranes. In conclusion, the higher efficiency for catch-up fat on high-lard diet than on LF cannot be explained by altered hepatic mitochondrial energetics. By contrast, the ability of the high-safflower oil diet to produce a less pronounced increase in the efficiency of catch-up fat may partly reside in increased incorporation of arachidonic acid in hepatic mitochondrial membranes, leading to enhanced proton leak and mitochondrial uncoupling.

Spontaneous Energy Concentration in Energetic Molecules, Interfaces and Composites: Response to Ultrasound and THz Radiation

Science.gov (United States)

2015-12-21

crystals or crystalline composites. One crystal had a slippery surface coating and the other did not. The coated ammonium nitrate , RDX and PBX...vibrational spectroscopies and time-resolved thermal imaging microscopy. 15. SUBJECT TERMS Ultrasound, THz radiation, energetic materials, hot spots, energy...studying fast processes at interfaces. 3. At the level of bulk materials, we developed a high-speed thermal imaging microscope apparatus.15󈧔

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,...

Nitrogen concentration profiles in oxy-nitrited high-speed steel

International Nuclear Information System (INIS)

Barcz, A.; Turos, A.; Wielunski, L.

1976-01-01

Nuclear microanalysis has been applied for the determination of in-depth concentration profiles of nitrogen in oxy-nitrided high-speed steel. The concentration profiles were deduced from measurements of the nitrogen content, determined by means of the 14 N(d,α) 12 C reaction for the set of initially identical samples after the removal of surface layers of sequentially increasing thicknesses. The 1.2 MeV deuterons were obtained from the Institute of Nuclear Research Van de Graaf accelerator LECH. The α-particles produced in the 14 N(d,α) 12 C reaction were detected by means of silicon surface barrier detector mounted at 150 deg C. Strong blocking of the nitrogen diffusion due to the presence of oxygen has been observed. The accuracy of nitrogen detection is of the order of 5% for nitrogen-rich regions and 10% for the matrix. However, the local non-uniformity of the steel may cause a spread of about 20% of the measured values. (T.G.)

Nitrogen-enriched carbon sheets derived from egg white by using expanded perlite template and its high-performance supercapacitors

Science.gov (United States)

Chen, Jiucun; Liu, Yinqin; Li, Wenjun; Xu, Liqun; Yang, Huan; Li, Chang Ming

2015-08-01

Nitrogen-enriched carbon sheets were synthesized using egg white as a unique carbon source and expanded perlite as a novel template. The as-prepared material was further used as an electrode material for supercapacitor applications, demonstrating excellent supercapacitance with a maximum gravimetric specific capacitance of 302 F g-1 at 0.5 A g-1 in a 3-electrode setup for a sample carbonized at 850 °C and activated for 6 h. Moreover, the carbon sheet-based capacitor with 2-symmetric electrodes showed an excellent cycle life (2% loss at 0.1 A g-1 after 10 000 cycles). The excellent performance may be attributed to the combination of the 3D carbon structure and the highly concentrated doped nitrogen component from the natural egg source for superior pseudocapacitance.

Polar conic current sheets as sources and channels of energetic particles in the high-latitude heliosphere

Science.gov (United States)

Khabarova, Olga; Malova, Helmi; Kislov, Roman; Zelenyi, Lev; Obridko, Vladimir; Kharshiladze, Alexander; Tokumaru, Munetoshi; Sokół, Justyna; Grzedzielski, Stan; Fujiki, Ken'ichi; Malandraki, Olga

2017-04-01

The existence of a large-scale magnetically separated conic region inside the polar coronal hole has been predicted by the Fisk-Parker hybrid heliospheric magnetic field model in the modification of Burger and co-workers (Burger et al., ApJ, 2008). Recently, long-lived conic (or cylindrical) current sheets (CCSs) have been found from Ulysses observations at high heliolatitudes (Khabarova et al., ApJ, 2017). The characteristic scale of these structures is several times lesser than the typical width of coronal holes, and the CCSs can be observed at 2-3 AU for several months. CCS crossings in 1994 and 2007 are characterized by sharp decreases in the solar wind speed and plasma beta typical for predicted profiles of CCSs. In 2007, a CCS was detected directly over the South Pole and strongly highlighted by the interaction with comet McNaught. The finding is confirmed by restorations of solar coronal magnetic field lines that reveal the occurrence of conic-like magnetic separators over the solar poles both in 1994 and 2007. Interplanetary scintillation data analysis also confirms the existence of long-lived low-speed regions surrounded by the typical polar high-speed solar wind in solar minima. The occurrence of long-lived CCSs in the high-latitude solar wind could shed light on how energetic particles reach high latitudes. Energetic particle enhancements up to tens MeV were observed by Ulysses at edges of CCSs both in 1994 and 2007. In 1994 this effect was clearer, probably due to technical reasons. Accelerated particles could be produced either by magnetic reconnection at the edges of a CCS in the solar corona or in the solar wind. We discuss the role of high-latitude CCSs in propagation of energetic particles in the heliosphere and revisit previous studies of energetic particle enhancements at high heliolatitudes. We also suggest that the existence of a CCS can modify the distribution of the solar wind as a function of heliolatitude and consequently impact ionization

Nitrogen: Unraveling the Secret to Stable Carbon-Supported Pt-Alloy Electrocatalysts

Science.gov (United States)

2013-10-01

release; distribution is unlimited. Nitrogen: unraveling the secret to stable carbon-supported Pt- alloy electrocatalysts The views, opinions and/or...Nitrogen: unraveling the secret to stable carbon-supported Pt-alloy electrocatalysts Report Title Nitrogen functionalities significantly improve...design and optimization of next generation high performance catalyst materials. Nitrogen: unraveling the secret to stable carbon-supported Pt-alloy

Nitrogen-doped ordered mesoporous carbon with a high surface area, synthesized through organic-inorganic coassembly, and its application in supercapacitors.

Science.gov (United States)

Song, Yanfang; Li, Li; Wang, Yonggang; Wang, Congxiao; Guo, Zaipin; Xia, Yongyao

2014-07-21

A new nitrogen-doped ordered mesoporous carbon (N-doped OMC) is synthesized by using an organic-inorganic coassembly method, in which resol is used as the carbon precursor, dicyandiamide as the nitrogen precursor, silicate oligomers as the inorganic precursors, and F127 as the soft template. The N-doped OMC possesses a surface area as high as 1374 m(2)  g(-1) and a large pore size of 7.4 nm. As an electrode material for supercapacitors, the obtained carbon exhibits excellent cycling stability and delivers a reversible specific capacitance as high as 308 F g(-1) in 1 mol L(-1) H(2)SO(4) aqueous electrolyte, of which 58 % of the capacity is due to pseudo-capacitance. The large specific capacitance is attributed to proper pore size distributions, large surface area, and high nitrogen content. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Temperature analysis of laser ignited metalized material using spectroscopic technique

Science.gov (United States)

Bassi, Ishaan; Sharma, Pallavi; Daipuriya, Ritu; Singh, Manpreet

2018-05-01

The temperature measurement of the laser ignited aluminized Nano energetic mixture using spectroscopy has a great scope in in analysing the material characteristic and combustion analysis. The spectroscopic analysis helps to do in depth study of combustion of materials which is difficult to do using standard pyrometric methods. Laser ignition was used because it consumes less energy as compared to electric ignition but ignited material dissipate the same energy as dissipated by electric ignition and also with the same impact. Here, the presented research is primarily focused on the temperature analysis of energetic material which comprises of explosive material mixed with nano-material and is ignited with the help of laser. Spectroscopy technique is used here to estimate the temperature during the ignition process. The Nano energetic mixture used in the research does not comprise of any material that is sensitive to high impact.

In Situ Activation of Nitrogen-Doped Graphene Anchored on Graphite Foam for a High-Capacity Anode.

Science.gov (United States)

Ji, Junyi; Liu, Jilei; Lai, Linfei; Zhao, Xin; Zhen, Yongda; Lin, Jianyi; Zhu, Yanwu; Ji, Hengxing; Zhang, Li Li; Ruoff, Rodney S

2015-08-25

We report the fabrication of a three-dimensional free-standing nitrogen-doped porous graphene/graphite foam by in situ activation of nitrogen-doped graphene on highly conductive graphite foam (GF). After in situ activation, intimate "sheet contact" was observed between the graphene sheets and the GF. The sheet contact produced by in situ activation is found to be superior to the "point contact" obtained by the traditional drop-casting method and facilitates electron transfer. Due to the intimate contact as well as the use of an ultralight GF current collector, the composite electrode delivers a gravimetric capacity of 642 mAh g(-1) and a volumetric capacity of 602 mAh cm(-3) with respect to the whole electrode mass and volume (including the active materials and the GF current collector). When normalized based on the mass of the active material, the composite electrode delivers a high specific capacity of up to 1687 mAh g(-1), which is superior to that of most graphene-based electrodes. Also, after ∼90 s charging, the anode delivers a capacity of about 100 mAh g(-1) (with respect to the total mass of the electrode), indicating its potential use in high-rate lithium-ion batteries.

Re-assessing the nitrogen signal in continental margin sediments: New insights from the high northern latitudes

Science.gov (United States)

Knies, Jochen; Brookes, Steven; Schubert, Carsten J.

2007-01-01

Organic and inorganic nitrogen and their isotopic signatures were studied in continental margin sediments off Spitsbergen. We present evidence that land-derived inorganic nitrogen strongly dilutes the particulate organic signal in coastal and fjord settings and accounts for up to 70% of the total nitrogen content. Spatial heterogeneity in inorganic nitrogen along the coast is less likely to be influenced by clay mineral assemblages or various substrates than by the supply of terrestrial organic matter (TOM) within eroded soil material into selected fjords and onto the shelf. The δ15N signal of the inorganic nitrogen ( δ15N inorg) in sediments off Spitsbergen seems to be appropriate to trace TOM supply from various climate- and ecosystem zones and elucidates the dominant transport media of terrigenous sediments to the marine realm. Moreover, we postulate that with the study of sedimentary δ15N inorg in the Atlantic-Arctic gateway, climatically induced changes in catchment's vegetations in high northern latitudes may be reconstructed. The δ15N org signal is primarily controlled by the availability of nitrate in the dominating ocean current systems and the corresponding degree of utilization of the nitrate pool in the euphotic zone. Not only does this new approach allow for a detailed view into the nitrogen cycle for settings with purely primary-produced organic matter supply, it also provides new insights into both the deposition of marine and terrestrial nitrogen and its ecosystem response to (paleo-) climate changes.

Root-to-seed transport and metabolism of fixed nitrogen in soybean

International Nuclear Information System (INIS)

McClure, P.R.

1983-01-01

The great energetic demand of nitrogen fixation to support growth of the exceptionally high-N seeds is certainly a major yield barrier for soybeans. Transport of carbohydrate energy supplies to the root and of fixed nitrogen (N) from the root appear to contribute to the yield barrier, also. N is loaded into the soybean xylem stream principally as allantoin (ALL), and allantonic acid (ALLA), but xylem carries only dilute N and cannot reach the seeds at sufficient rate to support their N needs. Explants consisting of stem and a few leaves and pods were allowed to take up 14 C- and/or 15 N-ALL/ALLA in synthetic xylem sap. The 14 C label was found to become fairly quantitatively immobilized in leaves. The N (and 15 N label) almost certainly is separated from the C( 14 C label) at this time

Theoretical Investigations of Novel Materials for Nitrogen Fixation

DEFF Research Database (Denmark)

Howalt, Jakob Geelmuyden

This thesis is dedicated to the investigation and design of new catalyst materials for electrochemical ammonia production and especially the properties of the under-coordinated reaction sites on nanoparticles has been studied in great detail. Additionally, a universal transition state relation...... choice of reference systems the transition state scaling relations form a universality class that can be approximated with one single linear relation describing the entire range of reactions over all types of surfaces and nanoclusters. Theoretical studies of producing ammonia electrochemically at ambient...... hydrogen and nitrogen. These scaling relations and free energy corrections are used to establish volcanoes describing the onset potential for electrochemical ammonia production and hence describe the potential determining steps for the electrochemical ammonia production. The competing hydrogen evolution...

High-strength shape memory steels alloyed with nitrogen

International Nuclear Information System (INIS)

Ullakko, K.; Jakovenko, P.T.; Gavriljuk, V.G.

1996-01-01

Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

Tribological properties of nitrogen implanted and boron implanted steels

International Nuclear Information System (INIS)

Kern, K.T.

1996-01-01

Samples of a steel with high chrome content was implanted separately with 75 keV nitrogen ions and with 75 keV boron ions. Implanted doses of each ion species were 2-, 4-, and 8 x 10 17 /cm 2 . Retained doses were measured using resonant non-Rutherford Backscattering Spectrometry. Tribological properties were determined using a pin-on-disk test with a 6-mm diameter ruby pin with a velocity of 0.94 m/min. Testing was done at 10% humidity with a load of 377 g. Wear rate and coefficient of friction were determined from these tests. While reduction in the wear rate for nitrogen implanted materials was observed, greater reduction (more than an order of magnitude) was observed for boron implanted materials. In addition, reduction in the coefficient of friction for high-dose boron implanted materials was observed. Nano-indentation revealed a hardened layer near the surface of the material. Results from grazing incidence x-ray diffraction suggest the formation of Fe 2 N and Fe 3 N in the nitrogen implanted materials and Fe 3 B in the boron implanted materials. Results from transmission electron microscopy will be presented

Energetic particle observations at the subsolar magnetopause

Directory of Open Access Journals (Sweden)

A. A. Eccles

Full Text Available The pitch-angle distributions (PAD of energetic particles are examined as the ISEE-1 satellite crosses the Earth’s magnetopause near the subsolar point. The investigation focuses on the possible existence of a particular type of distribution that would be associated with a source of energetic particles in the high-latitude magnetosphere. PADs, demonstrating broad, persistent field-aligned fluxes filling a single hemisphere (upper/northern or lower/southern, were observed just sunward of the magnetopause current layer for an extended period of many minutes. These distributions are a direct prediction of a possible source of energetic particles located in the high altitude dayside cusp and we present five examples in detail of the three-dimensional particle distributions to demonstrate their existence. From these results, other possible causes of such PADs are examined.

Key words. Magnetospheric physics (energetic particles, precipitating; magnetopause, cusp and boundary layers; magnetospheric configuration and dynamics

Time-dependent delayed signatures from energetic photon interrogations

International Nuclear Information System (INIS)

Norman, Daren R.; Jones, James L.; Blackburn, Brandon W.; Haskell, Kevin J.; Johnson, James T.; Watson, Scott M.; Hunt, Alan W.; Spaulding, Randy; Harmon, Frank

2007-01-01

Pulsed photonuclear interrogation environments generated by 8-24 MeV electron linac are rich with time-dependent, material-specific, radiation signatures. Nitrogen-based explosives and nuclear materials can be detected by exploiting these signatures in different delayed-time regions. Numerical and experimental results presented in this paper show the unique time and energy dependence of these signatures. It is shown that appropriate delayed-time windows are essential to acquire material-specific signatures in pulsed photonuclear assessment environments. These developments demonstrate that pulsed, high-energy, photon-inspection environments can be exploited for time-dependent, material-specific signatures through the proper operation of specialized detectors and detection methods

Assessment of accident energetics in LMFBR core-disruptive accidents

International Nuclear Information System (INIS)

Fauske, H.K.

1977-01-01

An assessment of accident energetics in LMFBR core-disruptive accidents is given with emphasis on the generic issues of energetic recriticality and energetic fuel-coolant interaction events. Application of a few general behavior principles to the oxide-fueled system suggests that such events are highly unlikely following a postulated core meltdown event

2016 Energetic Materials Gordon Research Conference and Gordon Research Seminar Research Area 7: Chemical Sciences 7.0 Chemical Sciences (Dr. James K. Parker)

Science.gov (United States)

2016-08-10

Energetic Materials" 8:45 pm - 8:55 pm Discussion 8:55 pm - 9:20 pm Michael Zdilla (Temple University, USA) "Expedition to Breach the CHNO Ceiling by...Introduction by Discussion Leader 9:15 am - 9:45 am Ryan Austin (Lawrence Livermore National Laboratory, USA) "Investigating the Crystal -Level

Achieving a long-lived high-beta plasma state by energetic beam injection

Science.gov (United States)

Guo, H. Y.; Binderbauer, M. W.; Tajima, T.; Milroy, R. D.; Steinhauer, L. C.; Yang, X.; Garate, E. G.; Gota, H.; Korepanov, S.; Necas, A.; Roche, T.; Smirnov, A.; Trask, E.

2015-04-01

Developing a stable plasma state with high-beta (ratio of plasma to magnetic pressures) is of critical importance for an economic magnetic fusion reactor. At the forefront of this endeavour is the field-reversed configuration. Here we demonstrate the kinetic stabilizing effect of fast ions on a disruptive magneto-hydrodynamic instability, known as a tilt mode, which poses a central obstacle to further field-reversed configuration development, by energetic beam injection. This technique, combined with the synergistic effect of active plasma boundary control, enables a fully stable ultra-high-beta (approaching 100%) plasma with a long lifetime.

Arcing time analysis of liquid nitrogen with respect to electrode materials

Science.gov (United States)

Junaid, Muhammad; Yang, Kun; Ge, Hanming; Wang, Jianhua

2018-03-01

Unlike sulphur hexafluoride (SF6), liquid nitrogen (LN2) is cost effective, environment friendly and cryogenic dielectric. It has astounding insulating properties with the potential to decrease power loss in switchgear applications due to its remarkably low temperatures. The basic research is however a necessity to observe the performance of LN2 subjected to high luminance arcs. So far, there are no findings that refer to the arcing time inside the LN2 environment. The objective of this work was to investigate the arcing times in LN2 and compare the results with open air conditions using different electrode materials. Experiments were conducted on different DC voltages and their arcing times were measured. Three different kinds of electrode materials, namely: pure copper (Cu), stainless used steel (SUS) and aluminium alloy (Al 6061) were tested under 1 atmospheric pressure. The results revealed that LN2 extinguishes arc in almost half the amount of time required by the open air insulation. With Al 6061 has the shortest arcing time, whilst Cu, the second best choice and SUS places last in the evaluation. It was encapsulated from the findings that LN2 is a better choice than air insulation in terms of arc quenching and a better alternative to SF6 when environment is the priority.

Organic materials: sources of nitrogen in the organic production of lettuce

OpenAIRE

MANOJLOVIC, Maja; CABILOVSKI, Ranko; BAVEC, Martina

2010-01-01

This paper presents the results of 2 experiments: an incubation experiment and a subsequent field experiment. An incubation experiment was set up in order to determine the mineralization potential of different organic materials (OMs) (well-rotted farmyard manure [FTM], guano [G], soybean seed [S], and forage pea seed [P]), the kinetics of mineral nitrogen (N) release, and the correlation between OM content and the quantity of mineralized N. The results of the incubation experiment were checke...

Highly efficient transition metal and nitrogen co-doped carbide-derived carbon electrocatalysts for anion exchange membrane fuel cells

Science.gov (United States)

Ratso, Sander; Kruusenberg, Ivar; Käärik, Maike; Kook, Mati; Puust, Laurits; Saar, Rando; Leis, Jaan; Tammeveski, Kaido

2018-01-01

The search for an efficient electrocatalyst for oxygen reduction reaction (ORR) to replace platinum in fuel cell cathode materials is one of the hottest topics in electrocatalysis. Among the many non-noble metal catalysts, metal/nitrogen/carbon composites made by pyrolysis of cheap materials are the most promising with control over the porosity and final structure of the catalyst a crucial point. In this work we show a method of producing a highly active ORR catalyst in alkaline media with a controllable porous structure using titanium carbide derived carbon as a base structure and dicyandiamide along with FeCl3 or CoCl2 as the dopants. The resulting transition metal-nitrogen co-doped carbide derived carbon (M/N/CDC) catalyst is highly efficient for ORR electrocatalysis with the activity in 0.1 M KOH approaching that of commercial 46.1 wt.% Pt/C. The catalyst materials are also investigated by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy to characterise the changes in morphology and composition causing the raise in electrochemical activity. MEA performance of M/N/CDC cathode materials in H2/O2 alkaline membrane fuel cell is tested with the highest power density reached being 80 mW cm-2 compared to 90 mW cm-2 for Pt/C.

Strong lithium polysulfide chemisorption on electroactive sites of nitrogen-doped carbon composites for high-performance lithium-sulfur battery cathodes.

Science.gov (United States)

Song, Jiangxuan; Gordin, Mikhail L; Xu, Terrence; Chen, Shuru; Yu, Zhaoxin; Sohn, Hiesang; Lu, Jun; Ren, Yang; Duan, Yuhua; Wang, Donghai

2015-03-27

Despite the high theoretical capacity of lithium-sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g(-1) after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm(-2)) with a high sulfur loading of approximately 5 mg cm(-2), which is ideal for practical applications of the lithium-sulfur batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inherent N,O-containing carbon frameworks as electrode materials for high-performance supercapacitors.

Science.gov (United States)

Hu, Fangyuan; Wang, Jinyan; Hu, Shui; Li, Linfei; Wang, Gang; Qiu, Jieshan; Jian, Xigao

2016-09-15

N,O-Containing micropore-dominated materials have been developed successfully via temperature-dependent cross-linking of 4,4'-(dioxo-diphenyl-2,3,6,7-tetraazaanthracenediyl)dibenzonitrile (DPDN) monomers. By employing a molecular engineering strategy, we have designed and synthesized a series of porous heteroatom-containing carbon frameworks (PHCFs), in which nitrogen and oxygen heteroatoms are distributed homogeneously throughout the whole framework at the atomic level, which can ensure the stability of its electrical properties. The as-made PHCFs@550 exhibits a high specific capacitance of 378 F g -1 , with an excellent long cycling life, including excellent cycling stability (capacitance retention of ca. 120% over 20 000 cycles). Moreover, the successful preparation of PHCFs provides new insights for the fabrication of nitrogen and oxygen-containing electrode materials from readily available components via a facile route.

The effect of high pressure on nitrogen compounds of milk

International Nuclear Information System (INIS)

Kielczewska, Katarzyna; Czerniewicz, Maria; Michalak, Joanna; Brandt, Waldemar

2004-01-01

The effect of pressurization at different pressures (from 200 to 1000 MPa, at 200 MPa intervals, t const. = 15 min) and periods of time (from 15 to 35 min, at 10 min intervals, p const. = 800 MPa) on the changes of proteins and nitrogen compounds of skimmed milk was studied. The pressurization caused an increase in the amount of soluble casein and denaturation of whey proteins. The level of nonprotein nitrogen compounds and proteoso-peptone nitrogen compounds increased as a result of the high-pressure treatment. These changes increased with an increase in pressure and exposure time. High-pressure treatment considerably affected the changes in the conformation of milk proteins, which was reflected in the changes in the content of proteins sedimenting and an increase in their degree of hydration

One-Step Synthesis of Microporous Carbon Monoliths Derived from Biomass with High Nitrogen Doping Content for Highly Selective CO2 Capture

OpenAIRE

Geng, Zhen; Xiao, Qiangfeng; Lv, Hong; Li, Bing; Wu, Haobin; Lu, Yunfeng; Zhang, Cunman

2016-01-01

The one-step synthesis method of nitrogen doped microporous carbon monoliths derived from biomass with high-efficiency is developed using a novel ammonia (NH3)-assisted activation process, where NH3 serves as both activating agent and nitrogen source. Both pore forming and nitrogen doping simultaneously proceed during the process, obviously superior to conventional chemical activation. The as-prepared nitrogen-doped active carbons exhibit rich micropores with high surface area and high nitrog...

High/low nitrogen adapted hybrid of rice cultivars and their ...

African Journals Online (AJOL)

Other four types were lying in the middle with moderate adaptability of nitrogen. Furthermore, five varieties were selected from each of the mentioned six types and then grew in N-free conditions to investigate their performance on lack of N. The results showed that type 1, the dry weight of the materials originally growing in ...

The production of Higgs bosons in high-energetic heavy-ion collisions

International Nuclear Information System (INIS)

Vidovic, M.

1991-09-01

The aim of this diploma thesis was to produce the Higgs boson in high-energetic, peripheral heavy-ion collisions by purely electromagnetic processes. In order to take only peripheral collisions into consideration and to avoid the strong hadronic background of central collisions the equivalent-photon method for the case of the Higgs boson was extended concerning an impact-parameter study. By this it was possible to exclude the contribution of central collisions by cut in the impact parameter at b=2R, in order to determine thus the production rate for purely peripheral collisions. (orig./HSI) [de

Interchannel interactions in high-energetic radiationless transitions of neon-like ions

International Nuclear Information System (INIS)

Fritzsche, S.; Zschornack, G.; Musiol, G.; Soff, G.

1990-07-01

Relativistic K-LL Auger transition rates in intermediate coupling including interchannel interactions are presented for nine ions in the neon-isoelectronic sequence up to uranium. For neutral neon a comparison with experimental data is given. We demonstrate for the first time, that intercontinuum interactions result in a remarkable redistribution of individual transition rates even in high-energetic transitions. For instance, channel mixing shifts the K-L 1 L 1 rate by about 4% and the K-L 3 L 3 (J = 0) rate by about 11% in neon-like uranium, while total Auger rates are almost not affected. (orig.)

Spectrophotometric and chromatographic determination of insensitive energetic materials: HNS and NTO, in the presence of sensitive nitro-explosives.

Science.gov (United States)

Can, Ziya; Uzer, Ayşem; Tekdemir, Yasemin; Erçağ, Erol; Türker, Lemi; Apak, Reşat

2012-02-15

As there are no molecular spectroscopic determination methods for the most widely used insensitive energetic materials, 2,2',4,4',6,6'-hexanitrostilbene (HNS) and 3-nitro-1,2,4-triazole-5-one (NTO), in the presence of sensitive nitro-explosives, two novel spectrophotometric methods were developed. For HNS and TNT mixtures, both analytes react with dicyclohexylamine (DCHA) forming different colored charge-transfer complexes, which can be resolved by derivative spectroscopy. The spectrophotometric method for NTO measures the 416-nm absorbance of its yellow-colored Na(+)NTO(-) salt formed with NaOH. TNT, if present, is pre-extracted into IBMK as its Meisenheimer anion forming an ion-pair with the cationic surfactant cetyl pyridinium (CP(+)) in alkaline medium, whereas the unextracted NTO is determined in the aqueous phase. The molar absorptivity (ε, L mol(-1)cm(-1)) and limit of quantification (LOQ, mg L(-1)) are as follows: for HNS, ε=2.75 × 10(4) and LOQ=0.48 (in admixture with TNT); for NTO, ε=6.83 × 10(3) and LOQ=0.73. These methods were not affected from nitramines and nitrate esters in synthetic mixtures or composite explosives. The developed methods were statistically validated against HPLC, and the existing chromatographic method was modified so as to enable NTO determination in the presence of TNT. These simple, low-cost, and versatile methods can be used in criminology, remediation/monitoring of contaminated sites, and kinetic stability modeling of munitions containing desensitized energetic materials. Copyright © 2012 Elsevier B.V. All rights reserved.

Raw material and energetic matrix: a synthetic, generic and attention considerations for the future of the Camacari Industrial pole, Bahia, Brazil; Materias-prima e matriz energetica: uma visao sintetica, generica e de atencao para o futuro do Polo Industrial de Camacari

Energy Technology Data Exchange (ETDEWEB)

Lins Neto, Joao Bispo [Braskem S.A., Camacari, BA (Brazil). Gerencia de Energia], e-mail: joao.lins@braskem.com.br; Lima, Alberto Ferreira [Bahia Pulp, Camacari, BA (Brazil). Gerencia de Qualidade e Desenvolvimento de Produto], e-mail: alberto_lima@bahiapulp.com; Petti, Ana Carla [Braskem S.A., Camacari, BA (Brazil). Gerencia de Gestao e Regulacao de Energia], e-mail: ana.petti@braskem.com.br; Correia, Antonia Lucia Santiago [PETROBRAS S.A., Norte/Nordeste (Brazil)

2008-01-15

This paper makes a synthetic evaluation of the present and raw material situation and the energetic matrix, and future perspectives, focusing on the following aspects: analysis of the existent production chains; threats to the raw material and incomes; integration between the enterprises and opportunities for new business, and availability and competitiveness of the energetic matrix.

Climate impact of idealized winter polar mesospheric and stratospheric ozone losses as caused by energetic particle precipitation

Science.gov (United States)

Meraner, Katharina; Schmidt, Hauke

2018-01-01

Energetic particles enter the polar atmosphere and enhance the production of nitrogen oxides and hydrogen oxides in the winter stratosphere and mesosphere. Both components are powerful ozone destroyers. Recently, it has been inferred from observations that the direct effect of energetic particle precipitation (EPP) causes significant long-term mesospheric ozone variability. Satellites observe a decrease in mesospheric ozone up to 34 % between EPP maximum and EPP minimum. Stratospheric ozone decreases due to the indirect effect of EPP by about 10-15 % observed by satellite instruments. Here, we analyze the climate impact of winter boreal idealized polar mesospheric and polar stratospheric ozone losses as caused by EPP in the coupled Max Planck Institute Earth System Model (MPI-ESM). Using radiative transfer modeling, we find that the radiative forcing of mesospheric ozone loss during polar night is small. Hence, climate effects of mesospheric ozone loss due to energetic particles seem unlikely. Stratospheric ozone loss due to energetic particles warms the winter polar stratosphere and subsequently weakens the polar vortex. However, those changes are small, and few statistically significant changes in surface climate are found.

Synthesis of Nitrogen-Doped Mesoporous Carbon for the Catalytic Oxidation of Ethylbenzene

Science.gov (United States)

Wang, Ruicong; Yu, Yifeng; Zhang, Yue; Lv, Haijun; Chen, Aibing

2017-06-01

Nitrogen-doped ordered mesoporous carbon (NOMC) was fabricated via a simple hard-template method by functionalized ionic liquids as carbon and nitrogen source, SBA-15 as a hard-template. The obtained NOMC materials have a high nitrogen content of 5.55 %, a high surface area of 446.2 m2 g-1, and an excellent performance in catalysing oxidation of ethylbenzene. The conversion rate of ethylbenzene can be up to 84.5% and the yield of acetophenone can be up to 69.9%, the results indicated that the NOMC materials have a faster catalytic rate and a higher production of acetophenone than catalyst-free and CMK-3, due to their uniform pore size, high surface area and rich active sites in the carbon pore walls.

MIL-100 derived nitrogen-embodied carbon shells embedded with iron nanoparticles

Science.gov (United States)

Mao, Chengyu; Kong, Aiguo; Wang, Yuan; Bu, Xianhui; Feng, Pingyun

2015-06-01

The use of metal-organic frameworks (MOFs) as templates and precursors to synthesize new carbon materials with controllable morphology and pre-selected heteroatom doping holds promise for applications as efficient non-precious metal catalysts. Here, we report a facile pyrolysis pathway to convert MIL-100 into nitrogen-doped carbon shells encapsulating Fe nanoparticles in a comparative study involving multiple selected nitrogen sources. The hierarchical porous architecture, embedded Fe nanoparticles, and nitrogen decoration endow this composite with a superior oxygen reduction activity. Furthermore, the excellent durability and high methanol tolerance even outperform the commercial Pt-C catalyst.The use of metal-organic frameworks (MOFs) as templates and precursors to synthesize new carbon materials with controllable morphology and pre-selected heteroatom doping holds promise for applications as efficient non-precious metal catalysts. Here, we report a facile pyrolysis pathway to convert MIL-100 into nitrogen-doped carbon shells encapsulating Fe nanoparticles in a comparative study involving multiple selected nitrogen sources. The hierarchical porous architecture, embedded Fe nanoparticles, and nitrogen decoration endow this composite with a superior oxygen reduction activity. Furthermore, the excellent durability and high methanol tolerance even outperform the commercial Pt-C catalyst. Electronic supplementary information (ESI) available: Material synthesis and elemental analysis, electrochemistry measurements, and additional figures. See DOI: 10.1039/c5nr02346g

Calculations on displacement damage and its related parameters for heavy ion bombardment in reactor materials

International Nuclear Information System (INIS)

Sone, Kazuho; Shiraishi, Kensuke

1975-04-01

The depth distribution of displacement damage expressed in displacements per atom (DPA) in reactor materials such as Mo, Nb, V, Fe and Ni bombarded by energetic nitrogen, argon and self ions with incident energy below 2 MeV was calculated following the theory developed by Lindhard and co-workers for the partition of energy as an energetic ion slowing down. In this calculation, energy loss due to electron excitation was taken into account for the atomic collision cascade after the primary knock-on process. Some parameters indispensable for the calculation such as energy loss rate, damage efficiency, projected range and its straggling were tabulated as a function of incident ion energy of 20 keV to 2 MeV. The damage and parameters were also calculated for 2 MeV nickel ions bombarding Fe targets. In this case, the DPA value is of 40--75% overestimated in a calculation disregarding electronic energy loss for primary knock-on atoms. The formula proposed in this report is significant for calculations on displacement damage produced by heavy ion bombardment as a simulation of high fluence fast neutron damage. (auth.)

Calculations on displacement damage and its related parameters for heavy ion bombardment in reactor materials

Energy Technology Data Exchange (ETDEWEB)

Sone, K; Shiraishi, K

1975-04-01

The depth distribution of displacement damage expressed in displacements per atom (DPA) in reactor materials such as Mo, Nb, V, Fe and Ni bombarded by energetic nitrogen, argon and self ions with incident energy below 2 MeV was calculated following the theory developed by Lindhard and co-workers for the partition of energy as an energetic ion slowing down. In this calculation, energy loss due to electron excitation was taken into account for the atomic collision cascade after the primary knock-on process. Some parameters indispensable for the calculation such as energy loss rate, damage efficiency, projected range and its straggling were tabulated as a function of incident ion energy of 20 keV to 2 MeV. The damage and parameters were also calculated for 2 MeV nickel ions bombarding Fe targets. In this case, the DPA value is of 40--75% overestimated in a calculation disregarding electronic energy loss for primary knock-on atoms. The formula proposed in this report is significant for calculations on displacement damage produced by heavy ion bombardment as a simulation of high fluence fast neutron damage.

Connection for transfer of Liquid Nitrogen from High Voltage to ground potential

DEFF Research Database (Denmark)

Rasmussen, Claus Nygaard; Hansen, Finn; Willén, Dag

2001-01-01

In order to operate a superconducting cable conductor it must be kept at a cryogenic temperature (e.g. using liquid nitrogen). The superconducting cable conductor is at high voltage and the cooling equipment is kept at ground potential. This requires a thermally insulating connection that is also...... properties and withstand towards high-pressure liquid nitrogen. The length per joint is approximately 900 mm, including a Johnstoncoupling. The joints are tested in a closed liquid nitrogen circuit, with a pressure of up to 10 bars. The rated voltage of the cable system is 36 kV (phase-phase)....

Nitrogen and sulfur co-doped porous graphene aerogel as an efficient electrode material for high performance supercapacitor in ionic liquid electrolyte

Science.gov (United States)

Chen, Yujuan; Liu, Zhaoen; Sun, Li; Lu, Zhiwei; Zhuo, Kelei

2018-06-01

Nitrogen and sulfur co-doped graphene aerogel (NS-GA) is prepared by one-pot process. The as-prepared materials are investigated as supercapacitors electrodes in an ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate, EMIMBF4) electrolyte. The NS-GA is characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy scanning electron microscopy. The results show that the NS-GA has hierarchical porous structure. Electrochemical performance is investigated by cycle voltammetry and galvanostatic charge-discharge. Notably, the supercapacitor based on the NS-GA-5 possesses a maximum energy density of 100.7 Wh kg-1 at power density of 0.94 kW kg-1. The electrode materials also offer a large specific capacitance of 203.2 F g-1 at a current density of 1 A g-1 and the capacitance retention of NS-GA-5 is 90% after 3000 cycles at a scan rate of 2 A g-1. The NS-GA-5 with numerous advantages including low cost and remarkable electrochemical behaviors can be a promising electrode material for the application of supercapacitors.

MOISTURE HUMIDITY EQUILIBRIUM OF WOOD CHIPS FROM ENERGETIC CROPS

Directory of Open Access Journals (Sweden)

Jan Barwicki

2008-09-01

Full Text Available Processes occurring during storage of wood chips for energetic or furniture industry purposes were presented. As a result of carried out investigations, dependences of temperature and relative humidity changes of surrounding air were shown. Modified Henderson equation can be utilized for computer simulation of storing and drying processes concerning wood chips for energetic and furniture industry purposes. It reflects also obtained results from experiments carried out with above mentioned material. Using computer simulation program we can examine different wood chips storing conditions to avoid overheating and loss problems.

The effect of different nitrogen fertilization rates on yield and quality of marigold (Calendula officinalis L. 'Tokaj' raw material

Directory of Open Access Journals (Sweden)

Beata Król

2012-12-01

Full Text Available Pot marigold (Calendula officinalis L. is an annual ornamental plant which is also grown for herbal raw material (flower heads used in the pharmaceutical and cosmetic industries. A field experiment was carried out in the years 2006-2008 in the Experimental Farm of the University of Life Sciences in Lublin. The study was conducted on loess soil with the granulometric composition of silt loam. The aim of the experiment was to determine the effect of different nitrogen rates (0, 40, 80, 120, 160 kg N × ha-1 on some morphological features of flower heads as well as on yield and quality of pot marigold raw material. Flowering of pot marigold was shortest in the control treatment (32 days and longest (43 days in the plot where nitrogen fertilization had been applied at the highest rate (160 kg N × ha-1. Nitrogen fertilization had a significant influence on the number of flower heads per plant, but no significant difference was found in diameter as well as in ligulate flowers and tubular flowers in the flower head. It was found to increase significantly raw material yield after the application of 80 kg N × ha-1, compared to the control treatment. Yield of flower heads did not differ markedly for fertilization rates from 80 to 160 kg N × ha-1. Nitrogen fertilization modified slightly essential oil content (this content increased with increasing nitrogen rates, but at the same time it decreased the percentage of flavonoid compounds.

Mechanism of NH{sub 3} desorption during the reaction of H{sub 2} with nitrogen containing carbonaceous materials

Energy Technology Data Exchange (ETDEWEB)

Juan F. Espinal; Thanh N. Truong; Fanor Mondragon [University of Antioquia, Medellin (Colombia). Institute of Chemistry

2005-07-01

The continued increase in demand for natural gas has stimulated the interest in coal conversion to methane as synthetic natural gas by hydropyrolysis of coal (pyrolysis in a H{sub 2} atmosphere). Because the produced raw gas contains considerable amounts of gaseous N-containing products that have to be removed before delivering to final users, the information on distribution of coal-N is important for designing purification processes. It has been reported in the literature that NH{sub 3} is the main nitrogen containing gas that is released during the hydropyrolysis process. Other gases such as HCN and N{sub 2} are also released but in a much smaller amount. To the best of our knowledge, the mechanism for NH{sub 3} desorption during hydrogen reaction with carbonaceous materials has not been studied. We carried out a molecular modeling study using Density Functional Theory in order to get an insight of the mechanism and thermodynamics for NH{sub 3} evolution using pyridinic nitrogen as a model of N-containing carbonaceous material. We propose a mechanism that involves consecutive hydrogenation steps that lead to C-N bond breakage and NH{sub 3} desorption to the gas phase. It was found that the first hydrogenation reaction is highly exothermic. However, further hydrogenations are endothermic. Several pathways for NH{sub 3} evolution were proposed and most of them show high exothermicity. 17 refs., 2 figs.

Principles of alloy design in high nitrogen 12% chromium steels

International Nuclear Information System (INIS)

Goecmen, A.; Ernst, P.; Holmes, P.

1999-01-01

12% chromium steels are hardened by a martensitic transformation and by precipitation reactions of the martensite during a subsequent tempering treatment. The original alloy design of these steels is based on the intensifying effect of C on the martensitic transformation hardening as well as on the effects of V and Mo on intensity and stability of carbide precipitation hardening reactions. Advanced alloy design of high carbon 12% chromium steels makes use of f.c.c.-MX type carbonitrides to improve grain refinement and tempering resistance, whereas alloying with about 0.05 wt.-% nitrogen already plays a decisive role. In this paper, new alloy design opportunities provided by high nitrogen are reviewed, which promise to achieve a best possible compromise between grain size limitation, particle hardening and particle stability of 12% chromium steels. The crucial effects of the solubility product of MX-type phases on grain coarsening resistance, precipitation hardening and particle stability are reviewed. The advantages of high nitrogen steels to improve these properties are rationalized to result from the lower solubility of nitrides compared with carbides. As an advantageous opportunity of the achievable higher grain coarsening resistance, the normalizing temperature in high nitrogen steels can be increased in order to increase the amount of the less soluble and thereby slow coarsening f.c.c.-nitrides. In addition, as a consequence of a higher normalizing temperature, the solubility gap of nitrides in the austenite is expanded, which in turn enables an effective precipitation hardening due to low soluble nitrides in the metastable austenite before the martensitic transformation

Thermal Plasma Spheroidization of High-Nitrogen Stainless Steel Powder Alloys Synthesized by Mechanical Alloying

Science.gov (United States)

Razumov, Nikolay G.; Popovich, Anatoly A.; Wang, QingSheng

2018-03-01

This paper presents the results of experimental studies on the treatment of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, synthesized by the mechanical alloying (MA) of elemental powders in the flow of a thermal plasma. Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys were prepared by MA in the attritor under an argon atmosphere. For spheroidization of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, the TekSphero 15 plant manufactured by Tekna Plasma Systems Inc was used. The studies have shown the possibility of obtaining Fe-23Cr-11Mn-1N high-nitrogen spherical powders steel alloys from the powder obtained by MA. According to the results of a series of experiments, it was found that the results of plasma spheroidization of powders essentially depend on the size of the fraction due to some difference in the particle shape and flowability, and on the gas regime of the plasma torch. It is established that during the plasma spheroidization process, some of the nitrogen leaves the alloy. The loss rate of nitrogen depends on the size of the initial particles.

The Use of an Edible Mushroom-Derived Renewable Carbon Material as a Highly Stable Electrocatalyst towards Four-Electron Oxygen Reduction

Directory of Open Access Journals (Sweden)

Chaozhong Guo

2015-12-01

Full Text Available The development of highly stable and efficient electrocatalysts for sluggish oxygen reduction reaction (ORR is exceedingly significant for the commercialization of fuel cells but remains a challenge. We here synthesize a new nitrogen-doped biocarbon composite material (N-BC@CNP-900 as a nitrogen-containing carbon-based electrocatalyst for the ORR via facile all-solid-state multi-step pyrolysis of bioprotein-enriched enoki mushroom as a starting material, and inexpensive carbon nanoparticles as the inserting matrix and conducting agent at controlled temperatures. Results show that the N-BC@CNP-900 catalyst exhibits the best ORR electrocatalytic activity with an onset potential of 0.94 V (versus reversible hydrogen electrode, RHE and high stability. Meanwhile, this catalyst significantly exhibits good selectivity of the four-electron reaction pathway in an alkaline electrolyte. It is notable that pyridinic- and graphtic-nitrogen groups that play a key role in the enhancement of the ORR activity may be the catalytically active structures for the ORR. We further propose that the pyridinic-nitrogen species can mainly stabilize the ORR activity and the graphitic-nitrogen species can largely enhance the ORR activity. Besides, the addition of carbon support also plays an important role in the pyrolysis process, promoting the ORR electrocatalytic activity.

The Use of an Edible Mushroom-Derived Renewable Carbon Material as a Highly Stable Electrocatalyst towards Four-Electron Oxygen Reduction.

Science.gov (United States)

Guo, Chaozhong; Sun, Lingtao; Liao, Wenli; Li, Zhongbin

2015-12-23

The development of highly stable and efficient electrocatalysts for sluggish oxygen reduction reaction (ORR) is exceedingly significant for the commercialization of fuel cells but remains a challenge. We here synthesize a new nitrogen-doped biocarbon composite material (N-BC@CNP-900) as a nitrogen-containing carbon-based electrocatalyst for the ORR via facile all-solid-state multi-step pyrolysis of bioprotein-enriched enoki mushroom as a starting material, and inexpensive carbon nanoparticles as the inserting matrix and conducting agent at controlled temperatures. Results show that the N-BC@CNP-900 catalyst exhibits the best ORR electrocatalytic activity with an onset potential of 0.94 V ( versus reversible hydrogen electrode, RHE) and high stability. Meanwhile, this catalyst significantly exhibits good selectivity of the four-electron reaction pathway in an alkaline electrolyte. It is notable that pyridinic- and graphtic-nitrogen groups that play a key role in the enhancement of the ORR activity may be the catalytically active structures for the ORR. We further propose that the pyridinic-nitrogen species can mainly stabilize the ORR activity and the graphitic-nitrogen species can largely enhance the ORR activity. Besides, the addition of carbon support also plays an important role in the pyrolysis process, promoting the ORR electrocatalytic activity.

Synthesis of boron, nitrogen co-doped porous carbon from asphaltene for high-performance supercapacitors

Science.gov (United States)

Zhou, Ying; Wang, Dao-Long; Wang, Chun-Lei; Jin, Xin-Xin; Qiu, Jie-Shan

2014-08-01

Oxidized asphaltene (OA), a thermosetting material with plenty of functional groups, is synthesized from asphaltene (A) using HNO3/H2SO4 as the oxidizing agent. Boron, nitrogen co-doped porous carbon (BNC—OA) is prepared by carbonization of the mixture of boric acid and OA at 1173 K in an argon atmosphere. X-ray photoelectron spectroscopy (XPS) characterization reveals that the BNC—OA has a nitrogen content of 3.26 at.% and a boron content of 1.31 at.%, while its oxidation-free counterpart (BNC—SA) has a nitrogen content of 1.61 at.% and a boron content of 3.02 at.%. The specific surface area and total pore volume of BNC—OA are 1103 m2·g-1 and 0.921 cm3·g-1, respectively. At a current density of 0.1 A·g-1, the specific capacitance of BNC-OA is 335 F·g-1 and the capacitance retention can still reach 83% at 1 A·g-1. The analysis shows that the superior electrochemical performance of the BNC—OA is attributed to the pseudocapacitance behavior of surface heteroatom functional groups and an abundant pore-structure. Boron, nitrogen co-doped porous carbon is a promising electrode material for supercapacitors.

High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

Science.gov (United States)

Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

2015-01-01

Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g−1 present high specific capacities of the 308 and 200 F g−1 in KOH electrolyte at current densities of 0.1 and 10 A g−1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g−1 at 0.1 A g−1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry. PMID:26472144

High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

Science.gov (United States)

Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

2015-10-01

Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g-1 present high specific capacities of the 308 and 200 F g-1 in KOH electrolyte at current densities of 0.1 and 10 A g-1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g-1 at 0.1 A g-1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry.

Welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties

OpenAIRE

Raffi Mohammed; G. Madhusudhan Reddy; K. Srinivasa Rao

2017-01-01

High nitrogen stainless steel (HNS) is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion resistance. Conventional fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poo...

Dynamic fracture and hot-spot modeling in energetic composites

Science.gov (United States)

Grilli, Nicolò; Duarte, Camilo A.; Koslowski, Marisol

2018-02-01

Defects such as cracks, pores, and particle-matrix interface debonding affect the sensitivity of energetic materials by reducing the time-to-ignition and the threshold pressure to initiate an explosion. Frictional sliding of preexisting cracks is considered to be one of the most important causes of localized heating. Therefore, understanding the dynamic fracture of crystalline energetic materials is of extreme importance to assess the reliability and safety of polymer-bonded explosives. Phase field damage model simulations, based on the regularization of the crack surface as a diffuse delta function, are used to describe crack propagation in cyclotetramethylene-tetranitramine crystals embedded in a Sylgard matrix. A thermal transport model that includes heat generation by friction at crack interfaces is coupled to the solution of crack propagation. 2D and 3D dynamic compression simulations are performed with different boundary velocities and initial distributions of cracks and interface defects to understand their effect on crack propagation and heat generation. It is found that, at an impact velocity of 400 m/s, localized damage at the particle-binder interface is of key importance and that the sample reaches temperatures high enough to create a hot-spot that will lead to ignition. At an impact velocity of 10 m/s, preexisting cracks advanced inside the particle, but the increase of temperature will not cause ignition.

T- P Phase Diagram of Nitrogen at High Pressures

Science.gov (United States)

Algul, G.; Enginer, Y.; Yurtseven, H.

2018-05-01

By employing a mean field model, calculation of the T- P phase diagram of molecular nitrogen is performed at high pressures up to 200 GPa. Experimental data from the literature are used to fit a quadratic function in T and P, describing the phase line equations which have been derived using the mean field model studied here for N 2, and the fitted parameters are determined. Our model study gives that the observed T- P phase diagram can be described satisfactorily for the first-order transitions between the phases at low as well as high pressures in nitrogen. Some thermodynamic quantities can also be predicted as functions of temperature and pressure from the mean field model studied here and they can be compared with the experimental data.

X-ray spectroscopic technique for energetic electron transport studies in short-pulse laser/plasma interactions

Energy Technology Data Exchange (ETDEWEB)

Tutt, T.E.

1994-12-01

When a solid target is irradiated by a laser beam, the material is locally heated to a high temperature and a plasma forms. The interaction of the laser with plasma can produce energetic electrons. By observing the behavior of these {open_quotes}hot{close_quotes} electrons, we hope to obtain a better understanding of Laser/Plasma Interactions. In this work we employ a layered-fluorescer technique to study the transport, and therefore the energetics, of the electrons. The plasma forms on a thin foil of metallic Pd which is bonded to thin layer of metallic Sn. Electrons formed from the plasma penetrate first the Pd and then the Sn. In both layers the energetic electrons promote inner (K) shell ionization of the metallic atoms which leads to the emission of characteristic K{sub {alpha}} x-rays of the fluorescers. By recording the x-ray spectrum emitted by the two foils, we can estimate the energy-dependent range of the electrons and their numbers.

Composite with a metallic matrix Al-AlN: from the powder to the material; Composite a matrice metallique A1-A1N: de la poudre au materiau

Energy Technology Data Exchange (ETDEWEB)

Troadec, C.

1996-05-09

Two types of powders are used: a `composite` powder synthesized by direct nitridation of aluminium by nitrogen, and a `mixed` powder obtained by a mixture of Al and AlN powders. These two powders types are crushed in a high energetic planetary crusher under an Ar atmosphere, then they are sintered under solid phase hot pressure. Microstructure of these materials, studied by Tem and XED, is relatively heterogenous, with high density polycrystalline area and high porous nano-crystals area. Size of these porous area are higher in `mixed` powders, and is linked to AlN percentage and to the crushing time. High density area are composed of Al grains surrounded by AlN nano-crystals with Al{sub 2}O{sub 3} needles and few aluminium oxynitride crystals. Physicochemical and mechanical properties, wear and corrosion comportment differ in function of the initial powders (`mixed` or `composite`) and with the AlN percentage. These new materials have, at similar reinforcement concentration, equivalent properties to Al/SiC or Al/Al{sub 2}O{sub 3} materials. (A.B.) 112 refs.

Energetic Sustainability and the Environment: A Transdisciplinary, Economic–Ecological Approach

Directory of Open Access Journals (Sweden)

Ioan G. Pop

2017-05-01

Full Text Available The paper combines original concepts about eco-energetic systems, in a transdisciplinary sustainable context. Firstly, it introduces the concept of M.E.N. (Mega-Eco-Nega-Watt, the eco-energetic paradigm based on three different but complementary ecological economic spaces: the Megawatt as needed energy, the Ecowatt as ecological energy, and the Negawatt as preserved energy. The paper also deals with the renewable energies and technologies in the context of electrical energy production. Secondly, in the context of the M.E.N. eco-energetic paradigm, comprehensive definitions are given about eco-energetic systems and for pollution. Thirdly, the paper introduces a new formula for the eco-energetic efficiency which correlates the energetic efficiency of the system and the necessary newly defined ecological coefficient. The proposed formula for eco-energetic efficiency enables an interesting form of relating to different situations in which the input energy, output energy, lost energy, and externalities involved in an energetic process, interact to produce energy in a specific energetic system, in connection with the circular resilient economy model. Finally, the paper presents an original energetic diagram to explain different channels to produce electricity in a resilience regime, with high eco-energetic efficiency from primary external energetic sources (gravitation and solar sources, fuels (classical and radioactive, internal energetic sources (geothermal, volcanoes and other kind of sources. Regardless the kind of energetic sources used to obtain electricity, the entire process should be sustainable in what concerns the transdisciplinary integration of the different representative spheres as energy, socio-economy, and ecology (environment.

Mineral commodity profiles: nitrogen

Science.gov (United States)

Kramer, Deborah A.

2004-01-01

Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

Refined energetic ordering for sulphate-water (n = 3-6) clusters using high-level electronic structure calculations

Science.gov (United States)

Lambrecht, Daniel S.; McCaslin, Laura; Xantheas, Sotiris S.; Epifanovsky, Evgeny; Head-Gordon, Martin

2012-10-01

This work reports refinements of the energetic ordering of the known low-energy structures of sulphate-water clusters ? (n = 3-6) using high-level electronic structure methods. Coupled cluster singles and doubles with perturbative triples (CCSD(T)) is used in combination with an estimate of basis set effects up to the complete basis set limit using second-order Møller-Plesset theory. Harmonic zero-point energy (ZPE), included at the B3LYP/6-311 + + G(3df,3pd) level, was found to have a significant effect on the energetic ordering. In fact, we show that the energetic ordering is a result of a delicate balance between the electronic and vibrational energies. Limitations of the ZPE calculations, both due to electronic structure errors, and use of the harmonic approximation, probably constitute the largest remaining errors. Due to the often small energy differences between cluster isomers, and the significant role of ZPE, deuteration can alter the relative energies of low-lying structures, and, when it is applied in conjunction with calculated harmonic ZPEs, even alters the global minimum for n = 5. Experiments on deuterated clusters, as well as more sophisticated vibrational calculations, may therefore be quite interesting.

Creating high energy density in nuclei with energetic antiparticles

International Nuclear Information System (INIS)

Gibbs, W.R.

1986-01-01

The possibility of creating a phase change in nuclear matter using energetic antiprotons and antideuterons is examined. It is found that energy densities of the order of 2 GeV/c can be obtained for periods of approx.2 fm/c with the proper experimental selection of events. 10 refs., 7 figs

In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High Performance Supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Jeon, Ju Won [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Texas A & M Univ., College Station, TX (United States); Sharma, Ronish [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meduri, Praveen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arey, Bruce W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schaef, Herbert T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lutkenhaus, Jodie [Texas A & M Univ., College Station, TX (United States); Lemmon, John P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thallapally, Praveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nandasiri, Manjula I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGrail, B. Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nune, Satish K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-04-30

Electrochemical performance of the existing state-of-the art capacitors is not very high, key scientific barrier is that its charge storage mechanism wholly depends on adsorption of electrolyte on electrode. We present a novel method for the synthesis of nitrogen -doped porous carbons and address the drawback by precisely controlling composition and surface area. Nitrogen-doped porous carbon was synthesized using a self-sacrificial template technique without any additional nitrogen and carbon sources. They exhibited exceptionally high capacitance (239 Fg-1) due to additional pseudocapacitance originating from doped nitrogen. Cycling tests showed no obvious capacitance decay even after 10,000 cycles, which meets the requirement of commercial supercapacitors. Our method is simple and highly efficient for the production of large quantities of nitrogen-doped porous carbons.

Papers of 4. Scientific-Technical Seminar: Material Study for Electric Power Stations and Energetics; Referaty 4. Seminarium Naukowo-Techniczne: Badania Materialowe na Potrzeby Elektrowni i Przemyslu Energetycznego

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-07-01

The research on the materials commonly used in electric power stations and energetics have been summarized in the course of the seminar. Especially a different kinds of steels have been investigated from the view point of their desirable mechanical and corrosion properties.

Reactions of Ground State Nitrogen Atoms N(4S) with Astrochemically-Relevant Molecules on Interstellar Dusts

Science.gov (United States)

Krim, Lahouari; Nourry, Sendres

2015-06-01

In the last few years, ambitious programs were launched to probe the interstellar medium always more accurately. One of the major challenges of these missions remains the detection of prebiotic compounds and the understanding of reaction pathways leading to their formation. These complex heterogeneous reactions mainly occur on icy dust grains, and their studies require the coupling of laboratory experiments mimicking the extreme conditions of extreme cold and dilute media. For that purpose, we have developed an original experimental approach that combine the study of heterogeneous reactions (by exposing neutral molecules adsorbed on ice to non-energetic radicals H, OH, N...) and a neon matrix isolation study at very low temperatures, which is of paramount importance to isolate and characterize highly reactive reaction intermediates. Such experimental approach has already provided answers to many questions raised about some astrochemically-relevant reactions occurring in the ground state on the surface of dust grain ices in dense molecular clouds. The aim of this new present work is to show the implication of ground state atomic nitrogen on hydrogen atom abstraction reactions from some astrochemically-relevant species, at very low temperatures (3K-20K), without providing any external energy. Under cryogenic temperatures and with high barrier heights, such reactions involving N(4S) nitrogen atoms should not occur spontaneously and require an initiating energy. However, the detection of some radicals species as byproducts, in our solid samples left in the dark for hours at 10K, proves that hydrogen abstraction reactions involving ground state N(4S) nitrogen atoms may occur in solid phase at cryogenic temperatures. Our results show the efficiency of radical species formation stemming from non-energetic N-atoms and astrochemically-relevant molecules. We will then discuss how such reactions, involving nitrogen atoms in their ground states, might be the first key step

Filler metal selection for welding a high nitrogen stainless steel

Science.gov (United States)

Du Toit, Madeleine

2002-06-01

Cromanite is a high-strength austenitic stainless steel that contains approximately 19% chromium, 10% manganese, and 0.5% nitrogen. It can be welded successfully, but due to the high nitrogen content of the base metal, precautions have to be taken to ensure sound welds with the desired combination of properties. Although no matching filler metals are currently available, Cromanite can be welded using a range of commercially available stainless steel welding consumables. E307 stainless steel, the filler metal currently recommended for joining Cromanite, produces welds with mechanical properties that are generally inferior to those of the base metal. In wear applications, these lower strength welds would probably be acceptable, but in applications where full use is made of the high strength of Cromanite, welds with matching strength levels would be required. In this investigation, two welding consumables, ER2209 (a duplex austenitic-ferritic stainless steel) and 15CrMn (an austenitic-manganese hardfacing wire), were evaluated as substitutes for E307. When used to join Cromanite, 15CrMn produced welds displaying severe nitrogen-induced porosity, and this consumable is therefore not recommended. ER2209, however, outperformed E307, producing sound porosity-free welds with excellent mechanical properties, including high ductility and strength levels exceeding the minimum limits specified for Cromanite.

Highly selective deuteration of pharmaceutically relevant nitrogen-containing heterocycles: a flow chemistry approach.

Science.gov (United States)

Ötvös, Sándor B; Mándity, István M; Fülöp, Ferenc

2011-08-01

A simple and efficient flow-based technique is reported for the catalytic deuteration of several model nitrogen-containing heterocyclic compounds which are important building blocks of pharmacologically active materials. A continuous flow reactor was used in combination with on-demand pressure-controlled electrolytic D(2) production. The D(2) source was D(2)O, the consumption of which was very low. The experimental set-up allows the fine-tuning of pressure, temperature, and flow rate so as to determine the optimal conditions for the deuteration reactions. The described procedure lacks most of the drawbacks of the conventional batch deuteration techniques, and additionally is highly selective and reproducible.

Nanostructured nitrogen-doped mesoporous carbon derived from polyacrylonitrile for advanced lithium sulfur batteries

Energy Technology Data Exchange (ETDEWEB)

Liu, Ying; Zhao, Xiaohui; Chauhan, Ghanshyam S. [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology and RIGET, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of)

2016-09-01

Graphical abstract: Well-ordered nitrogen-doped mesoporous carbon materials were prepared by in-situ polymerization of polyacrylonitrile in SBA-15 template. The composite of sulfur and nitrogen-doped carbon was successfully used as a cathode material for lithium sulfur battery. - Highlights: • N-doped mesoporous carbons were prepared with PAN as carbon source. • Highly ordered pore system facilitates sulfur loading. • Ladder-type carbon matrix provides good structural stability for confining sulfur. • N-doping ensures an improved absorbability of soluble polysulfides. - Abstract: Nitrogen doping in carbon matrix can effectively improve the wettability of electrolyte and increase electric conductivity of carbon by ensuring fast transfer of ions. We synthesized a series of nitrogen-doped mesoporous carbons (CPANs) via in situ polymerization of polyacrylonitrile (PAN) in SBA-15 template followed by carbonization at different temperatures. Carbonization results in the formation of ladder structure which enhances the stability of the matrix. In this study, CPAN-800, carbon matrix synthesized by the carbonization at 800 °C, was found to possess many desirable properties such as high specific surface area and pore volume, moderate nitrogen content, and highly ordered mesoporous structure. Therefore, it was used to prepare S/CPAN-800 composite as cathode material in lithium sulfur (Li-S) batteries. The S/CPAN-800 composite was proved to be an excellent material for Li-S cells which delivered a high initial discharge capacity of 1585 mAh g{sup −1} and enhanced capacity retention of 862 mAh g{sup −1} at 0.1 C after 100 cycles.

Minnealloy: a new magnetic material with high saturation flux density and low magnetic anisotropy

Science.gov (United States)

Mehedi, Md; Jiang, Yanfeng; Suri, Pranav Kumar; Flannigan, David J.; Wang, Jian-Ping

2017-09-01

We are reporting a new soft magnetic material with high saturation magnetic flux density, and low magnetic anisotropy. The new material is a compound of iron, nitrogen and carbon, α‧-Fe8(NC), which has saturation flux density of 2.8  ±  0.15 T and magnetic anisotropy of 46 kJ m-3. The saturation flux density is 27% higher than pure iron, a widely used soft magnetic material. Soft magnetic materials are very important building blocks of motors, generators, inductors, transformers, sensors and write heads of hard disk. The new material will help in the miniaturization and efficiency increment of the next generation of electronic devices.

Changes in the content of total nitrogen and mineral nitrogen in the basil herb depending on the cultivar and nitrogen nutrition

Directory of Open Access Journals (Sweden)

Katarzyna Dzida

2013-04-01

Full Text Available Among fundamental nutrients, nitrogen fertilization is considered one of the most effective factors affecting both the yield and the quality of plant material. Nitrogen form used for fertilizing is also of great importance. The aim of this study was to investigate the impact of nitrogen nutrition (calcium nitrate, ammonium nitrate, and urea as well as (green, purple, and‘Fino Verde’ on the chemical composition and yielding of basil (Ocimum basilicumL.. After drying the plant material at a temperature of 60°C and milling, total nitrogen was determined by means of Kjeldahl method, while mineral nitrogen content (N-NH 4, N-NO 3 was analyzed in 2% acetic acid extract. Yield of fresh basil matter depended significantly on the variety grown. The highest yields were obtained from a cultivar of ‘Fino Verde’ fertilized with ammonium nitrate. The purple variety plants fertilized with urea were characterized by a largest amount of total nitrogen. The‘Fino Verde’cultivar fertilized with urea accumulated the least quantities of nitrates in the basil herb.

Energetically resolved multiple-fluid equilibria of tokamak plasmas

International Nuclear Information System (INIS)

Hole, M J; Dennis, G

2009-01-01

In many magnetically confined fusion experiments, a significant fraction of the stored energy of the plasma resides in energetic, or non-thermal, particle populations. Despite this, most equilibrium treatments are based on MHD: a single fluid treatment which assumes a Maxwell-Boltzmann distribution function. Detailed magnetic reconstruction based on this treatment ignore the energetic complexity of the plasma and can result in model-data inconsistencies, such as thermal pressure profiles which are inconsistent with the total stored kinetic energy of the plasma. Alternatively, ad hoc corrections to the pressure profile, such as summing the energetic and thermal pressures, have poor theoretical justification. Motivated by this omission, we generalize ideal MHD one step further: we consider multiple quasi-neutral fluids, each in thermal equilibrium and each thermally insulated from each other-no population mixing occurs. Kinetically, such a model may be able to describe the ion or electron distribution function in regions of velocity phase space with a large number of particles, at the expense of more weakly populated phase space, which may have uncharacteristically high temperature and hence pressure. As magnetic equilibrium effects increase with the increase in pressure, our work constitutes an upper limit to the effect of energetic particles. When implemented into an existing solver, FLOW (Guazzotto et al 2004 Phys. Plasmas 11, 604-14), it becomes possible to qualitatively explore the impact of resolving the energetic populations on plasma equilibrium configurations in realistic geometry. Deploying the modified code, FLOW-M, on a high performance spherical torus configuration, we find that the effect of variations of the pressure, poloidal flow and toroidal flow of the energetic populations is qualitatively similar to variations in the background plasma. We also study the robustness of the equilibrium to uncertainties in the current profile and the energetic

Beam-Material Interaction

CERN Document Server

Mokhov, N.V.

2016-01-01

Th is paper is motivated by the growing importance of better understanding of the phenomena and consequences of high- intensity energetic particle beam interactions with accelerator, generic target , and detector components. It reviews the principal physical processes of fast-particle interactions with matter, effects in materials under irradiation, materials response, related to component lifetime and performance, simulation techniques, and methods of mitigating the impact of radiation on the components and envir onment in challenging current and future application

Beam-Material Interaction

Energy Technology Data Exchange (ETDEWEB)

Mokhov, N. V. [Fermilab; Cerutti, F. [CERN

2016-01-01

Th is paper is motivated by the growing importance of better understanding of the phenomena and consequences of high-intensity energetic particle beam interactions with accelerator, generic target, and detector components. It reviews the principal physical processes of fast-particle interactions with matter, effects in materials under irradiation, materials response, related to component lifetime and performance, simulation techniques, and methods of mitigating the impact of radiation on the components and environment in challenging current and future applications.

Carbon nanocages: a new support material for Pt catalyst with remarkably high durability.

Science.gov (United States)

Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong

2014-03-24

Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for "real world" application.

Hydrothermal synthesis of NiCo2O4 nanowires/nitrogen-doped graphene for high-performance supercapacitor

International Nuclear Information System (INIS)

Yu, Mei; Chen, Jianpeng; Ma, Yuxiao; Zhang, Jingdan; Liu, Jianhua; Li, Songmei; An, Junwei

2014-01-01

Highlights: • NCO/NG composites were synthesized in a water–glycerol mixed solvent via hydrothermal treatment and subsequent calcination. • NiCo 2 O 4 nanowires are dispersed on NG nanosheets and the composite has porous structure. • The NCO/NG composite exhibits a high specific capacitance and long cycling performance. - Abstract: NiCo 2 O 4 nanowires/nitrogen-doped graphene (NCO/NG) composite materials were synthesized by hydrothermal treatment in a water–glycerol mixed solvent and subsequent thermal transformation. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The electrochemical performance of the composites was evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrum techniques. NiCo 2 O 4 nanowires are densely coated by nitrogen-doped graphene and the composite displays good electrochemical performance. The maximum specific capacitance of NCO/NG is 1273.13 F g −1 at 0.5 A g −1 in 6 M KOH aqueous solution, and it exhibits good capacity retention without noticeable degradation after 3000 cycles at 4 A g −1

High power laser research and development at the Laboratory for Laser Energetics

International Nuclear Information System (INIS)

Soures, J.M.; McCrory, R.L.; Cerqua, K.A.

1986-01-01

As part of its research mission - to investigate the interaction of intense radiation with matter - the Laboratory for Laser Energetics (LLE) of the University of Rochester is developing a number of high-peak power and high-average-power laser systems. In this paper we highlight some of the LLE work on solid-state laser research, development and applications. Specifically, we discuss the performance and operating characteristics of Omega, a twenty-four beam, 4000 Joule, Nd:glass laser system which is frequently tripled using the polarization mismatch scheme. We also discuss progress in efforts to develop high-average-power solid-state laser systems with active-mirror and slab geometries and to implement liquid-crystal devices in high-power Nd:glass lasers. Finally we present results from a program to develop a compact, ultrahigh-peak-power solid-state laser using the concept of frequency chirped pulse amplification

In situ one-step synthesis of hierarchical nitrogen-doped porous carbon for high-performance supercapacitors.

Science.gov (United States)

Jeon, Ju-Won; Sharma, Ronish; Meduri, Praveen; Arey, Bruce W; Schaef, Herbert T; Lutkenhaus, Jodie L; Lemmon, John P; Thallapally, Praveen K; Nandasiri, Manjula I; McGrail, Benard Peter; Nune, Satish K

2014-05-28

A hierarchically structured nitrogen-doped porous carbon is prepared from a nitrogen-containing isoreticular metal-organic framework (IRMOF-3) using a self-sacrificial templating method. IRMOF-3 itself provides the carbon and nitrogen content as well as the porous structure. For high carbonization temperatures (950 °C), the carbonized MOF required no further purification steps, thus eliminating the need for solvents or acid. Nitrogen content and surface area are easily controlled by the carbonization temperature. The nitrogen content decreases from 7 to 3.3 at % as carbonization temperature increases from 600 to 950 °C. There is a distinct trade-off between nitrogen content, porosity, and defects in the carbon structure. Carbonized IRMOFs are evaluated as supercapacitor electrodes. For a carbonization temperature of 950 °C, the nitrogen-doped porous carbon has an exceptionally high capacitance of 239 F g(-1). In comparison, an analogous nitrogen-free carbon bears a low capacitance of 24 F g(-1), demonstrating the importance of nitrogen dopants in the charge storage process. The route is scalable in that multi-gram quantities of nitrogen-doped porous carbons are easily produced.

Fractal dimension and energetic heterogeneity of gold-modified Al-Fe-Ce pilc's

International Nuclear Information System (INIS)

Carriazo, J.G.; Molina, R.; Moreno, S.

2008-01-01

This paper studies the energetic and topographical changes that occur on the surface of a series of clays pillared with the mixed Al-Fe-Ce system and on the surface of solids synthesized by the deposition of gold nanoparticles over these pillared clays. The energetic heterogeneity of the solids was analyzed by means of the distribution of the adsorption potential, while the variations in the fractal dimension were determined from the nitrogen adsorption isotherms at 77 K, using the equation proposed by Avnir-Jaroniec. Results show the generation of microporous structures with important topographical modifications indicating an increase in the roughness (fractal geometry) of the surface of the solids as a consequence of the pillaring, revealing a positive effect of cerium addition in the synthesis process and the possible formation of nanoparticles of iron species and gold on the surface of pillared clays. The solids were also analyzed by transmission electron microscopy (TEM), confirming the formation of nanoparticles on the surface.

Climate impact of idealized winter polar mesospheric and stratospheric ozone losses as caused by energetic particle precipitation

Directory of Open Access Journals (Sweden)

K. Meraner

2018-01-01

Full Text Available Energetic particles enter the polar atmosphere and enhance the production of nitrogen oxides and hydrogen oxides in the winter stratosphere and mesosphere. Both components are powerful ozone destroyers. Recently, it has been inferred from observations that the direct effect of energetic particle precipitation (EPP causes significant long-term mesospheric ozone variability. Satellites observe a decrease in mesospheric ozone up to 34 % between EPP maximum and EPP minimum. Stratospheric ozone decreases due to the indirect effect of EPP by about 10–15 % observed by satellite instruments. Here, we analyze the climate impact of winter boreal idealized polar mesospheric and polar stratospheric ozone losses as caused by EPP in the coupled Max Planck Institute Earth System Model (MPI-ESM. Using radiative transfer modeling, we find that the radiative forcing of mesospheric ozone loss during polar night is small. Hence, climate effects of mesospheric ozone loss due to energetic particles seem unlikely. Stratospheric ozone loss due to energetic particles warms the winter polar stratosphere and subsequently weakens the polar vortex. However, those changes are small, and few statistically significant changes in surface climate are found.

Energetic utilization and recycling of straw; Energetische und stoffliche Verwertung von Stroh

Energy Technology Data Exchange (ETDEWEB)

Schuech, Andrea; Engler, Nils; Weissbach, Gunter; Nelles, Michael [Rostock Univ. (Germany). Lehrstuhl Abfall- und Stoffstromwirtschaft

2013-10-01

Worldwide arising significant emissions caused by the burning of rice straw on the field. The combined energetic and material utilization of rice straw offers the production possibility of various usable bioenergy and the closing of nutrient cycles by the return of the conversion residues. Thereby the soil quality can be improved and an important contribution to climate protection and resource conservation be realized. In the German-Egyptian project CEMUWA, the options of material and energetic use of rice straw are investigated. It is used as substrate for plant cultivation and for the production of ethanol, butanol and biogas. In this paper first results are presented. (orig.)

TiO{sub 2} nanoparticles on nitrogen-doped graphene as anode material for lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Li Dan; Shi Dongqi [Institute for Superconducting and Electronic Materials, University of Wollongong (Australia); Liu Zongwen [University of Sydney, School of Chemical and Biomolecular Engineering (Australia); Liu Huakun; Guo Zaiping, E-mail: zguo@uow.edu.au [Institute for Superconducting and Electronic Materials, University of Wollongong (Australia)

2013-05-15

Anatase TiO{sub 2} nanoparticles in situ grown on nitrogen-doped, reduced graphene oxide (rGO) have been successfully synthesized as an anode material for the lithium ion battery. The nanosized TiO{sub 2} particles were homogeneously distributed on the reduced graphene oxide to inhibit the restacking of the neighbouring graphene sheets. The obtained TiO{sub 2}/N-rGO composite exhibits improved cycling performance and rate capability, indicating the important role of reduced graphene oxide, which not only facilitates the formation of uniformly distributed TiO{sub 2} nanocrystals, but also increases the electrical conductivity of the composite material. The introduction of nitrogen on the reduced graphene oxide has been proved to increase the conductivity of the reduced graphene oxide and leads to more defects. A disordered structure is thus formed to accommodate more lithium ions, thereby further improving the electrochemical performance.

Toxicity of Nitro-Heterocyclic and Nitroaromatic Energetic Materials to Folsomia candida in a Natural Sandy Loam Soil

Science.gov (United States)

2015-04-01

these tests. Acetone (CAS: 67-64-1; high-performance liquid chromatography [HPLC] grade) was used for preparing EM solutions during the soil amendments... chromatography grade, purity: 99.9%) was used in the HPLC determinations. Certified standards of the energetics (AccuStandard, Inc., New Haven, CT) were used...H.; Van Gestel, C.A.M. Handbook of Soil Invertebrate Toxicity Tests; John Wiley & Sons: Hoboken, NJ, 1998. McLellan, W.L.; Hartley, W.R.; Brower

Advanced Sulfur Cathode Enabled by Highly Crumpled Nitrogen-Doped Graphene Sheets for High-Energy-Density Lithium-Sulfur Batteries.

Science.gov (United States)

Song, Jiangxuan; Yu, Zhaoxin; Gordin, Mikhail L; Wang, Donghai

2016-02-10

Herein, we report a synthesis of highly crumpled nitrogen-doped graphene sheets with ultrahigh pore volume (5.4 cm(3)/g) via a simple thermally induced expansion strategy in absence of any templates. The wrinkled graphene sheets are interwoven rather than stacked, enabling rich nitrogen-containing active sites. Benefiting from the unique pore structure and nitrogen-doping induced strong polysulfide adsorption ability, lithium-sulfur battery cells using these wrinkled graphene sheets as both sulfur host and interlayer achieved a high capacity of ∼1000 mAh/g and exceptional cycling stability even at high sulfur content (≥80 wt %) and sulfur loading (5 mg sulfur/cm(2)). The high specific capacity together with the high sulfur loading push the areal capacity of sulfur cathodes to ∼5 mAh/cm(2), which is outstanding compared to other recently developed sulfur cathodes and ideal for practical applications.

Climate protection, natural resources management and soil improvement by combined Energetic and Material Utilization of lignocellulosic agricultural WAstes and residues (CEMUWA)

International Nuclear Information System (INIS)

Schuech, Andrea; Nelles, Michael; Tscherpel, Burckhard; El Behery, Ahmed; Menanz, Rania; Bahl, Hubert; Scheel, Michael; Nipkow, Mareen

2015-01-01

The project Climate protection, natural resources management and soil improvement by combined Energetic and Material Utilization of lignocellulosic agricultural WAstes and residues (CEMUWA) was implemented with long-term partners from Egypt and Germany leaded by the Department Waste Management and Material Flow from September 2011 until October 2013. Aim of the project was the development of technologies for the utilization of agricultural wastes and residues at the example of rice straw, with the focus on the energetic and material use. In the long term a contribution to climate protection and natural resource management could be reached. The focus was on investigations in the field of biogas, ethanol and butanol production including pretreatment as well as the material use in horticulture. The results show that the biogas and ethanol production with adapted pretreatments of rice straws is possible. The technical adaptation of a biogas plant (eo-digestion) would be associated with about 20% higher investment costs and higher operating costs with an approximately 15% higher energy demand. In Germany, however, this may still economically by the substitution of expensive or difficult available energy crops (reduction of substrate costs by 30 to 35% for a 600 kWel-BGP using maize silage). The investigated solutions for material use in Egypt showed good results, which in some cases exceeded the expectations. By the use of rice straw imported peat substrates could be substitute or irrigation water saved, what is ecologically and economically useful. The production of ethanol from rice straw was implemented on laboratory scale and preconditions for investigations in semi-industrial and partly pilot scale were created. The bilateral project'' was funded in the framework of the German-Egypt-Research-Fond (GERF) by the German Federal Ministry of Education and Research (BMBF) and the Egyptian Science and Technology Development Fund in Egypt (STDF). The total budget

Synthesis of ultrathin nitrogen-doped graphitic carbon nanocages as advanced electrode materials for supercapacitor.

Science.gov (United States)

Tan, Yueming; Xu, Chaofa; Chen, Guangxu; Liu, Zhaohui; Ma, Ming; Xie, Qingji; Zheng, Nanfeng; Yao, Shouzhuo

2013-03-01

Synthesis of nitrogen-doped carbons with large surface area, high conductivity, and suitable pore size distribution is highly desirable for high-performance supercapacitor applications. Here, we report a novel protocol for template synthesis of ultrathin nitrogen-doped graphitic carbon nanocages (CNCs) derived from polyaniline (PANI) and their excellent capacitive properties. The synthesis of CNCs involves one-pot hydrothermal synthesis of Mn3O4@PANI core-shell nanoparticles, carbonization to produce carbon coated MnO nanoparticles, and then removal of the MnO cores by acidic treatment. The CNCs prepared at an optimum carbonization temperature of 800 °C (CNCs-800) have regular frameworks, moderate graphitization, high specific surface area, good mesoporosity, and appropriate N doping. The CNCs-800 show high specific capacitance (248 F g(-1) at 1.0 A g(-1)), excellent rate capability (88% and 76% capacitance retention at 10 and 100 A g(-1), respectively), and outstanding cycling stability (~95% capacitance retention after 5000 cycles) in 6 M KOH aqueous solution. The CNCs-800 can also exhibit great pseudocapacitance in 0.5 M H2SO4 aqueous solution besides the large electrochemical double-layer capacitance. The excellent capacitance performance coupled with the facile synthesis of ultrathin nitrogen-doped graphitic CNCs indicates their great application potential in supercapacitors.

Polyaniline nanowire arrays aligned on nitrogen-doped carbon fabric for high-performance flexible supercapacitors.

Science.gov (United States)

Yu, Pingping; Li, Yingzhi; Yu, Xinyi; Zhao, Xin; Wu, Lihao; Zhang, Qinghua

2013-09-24

A combination of vertical polyaniline (PANI) nanowire arrays and nitrogen plasma etched carbon fiber cloths (eCFC) was fabricated to create 3D nanostructured PANI/eCFC composites. The small size of the highly ordered PANI nanowires can greatly reduce the scale of the diffusion length, allowing for the improved utilization of electrode materials. A two-electrode flexible supercapacitor based on PANI/eCFC demonstrates a high specific capacitance (1035 F g(-1) at a current density of 1 A g(-1)), good rate capability (88% capacity retention at 8 A g(-1)), and long-term cycle life (10% capacity loss after 5000 cycles). The lightweight, low-cost, flexible composites are promising candidates for use in energy storage device applications.

Ammoxidation of Lignocellulosic Materials: Formation of Nonheterocyclic Nitrogenous Compounds from Monosaccharides

Science.gov (United States)

2013-01-01

Ammoxidized technical lignins are valuable soil-improving materials that share many similarities with native terrestrial humic substances. In contrast to lignins, the chemical fate of carbohydrates as typical minor constituents of technical lignins during the ammoxidation processes has not been thoroughly investigated. Recently, we reported the formation of N-heterocyclic, ecotoxic compounds (OECD test 201) from both monosaccharides (d-glucose, d-xylose) and polysaccharides (cellulose, xylan) under ammoxidation conditions and showed that monosaccharides are a source more critical than polysaccharides in this respect. GC/MS-derivatization analysis of the crude product mixtures revealed that ammoxidation of carbohydrates which resembles the conditions encountered in nonenzymatical browning of foodstuff affords also a multitude of nonheterocyclic nitrogenous compounds such as aminosugars, glycosylamines, ammonium salts of aldonic, deoxyaldonic, oxalic and carbaminic acids, urea, acetamide, α-hydroxyamides, and even minor amounts of α-amino acids. d-Glucose and d-xylose afforded largely similar product patterns which differed from each other only for those products that were formed under preservation of the chain integrity and stereoconfiguration of the respective monosaccharide. The kinetics and reaction pathways involved in the formation of the different classes of nitrogenous compounds under ammoxidation conditions are discussed. PMID:23967905

Creation of nitrogen-vacancy centres in diamond with high resolution

Energy Technology Data Exchange (ETDEWEB)

Pezzagna, Sebastien; Meijer, Jan [Rubion, Ruhr-Universitaet Bochum (Germany); Wildanger, Dominik; Hell, Stefan W. [Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Goettingen (Germany); Mazarov, Paul; Wieck, Andreas D. [Lehrstuhl fuer Angewandte Festkoerperphysik, Ruhr-Universitaet Bochum (Germany); Naydenov, Boris; Jelezko, Fedor; Wrachtrup, Joerg [3. Institute of Physics, University of Stuttgart (Germany)

2010-07-01

Nowadays, diamond and the nitrogen-vacancy (NV) colour centres constitute the best solid-state system in view of quantum-computing applications. It has also been shown recently that single NV centres could be used as nanoscale magnetic sensors. Such applications require the creation of single NV centres with very high resolution and with a high efficiency. The nano-implanter at the university of Bochum provides low energy nitrogen ions which can be implanted through a hole pierced in the tip of an atomic force microscope. Ultrapure diamond samples have been implanted with spot sizes of 50nm and less. Stimulated Emission Depletion (STED) microscopy has been used to characterise and resolve the implanted spots.

Nitrogen-doped graphene: effect of graphite oxide precursors and nitrogen content on the electrochemical sensing properties.

Science.gov (United States)

Megawati, Monica; Chua, Chun Kiang; Sofer, Zdenek; Klímová, Kateřina; Pumera, Martin

2017-06-21

Graphene, produced via chemical methods, has been widely applied for electrochemical sensing due to its structural and electrochemical properties as well as its ease of production in large quantity. While nitrogen-doped graphenes are widely studied materials, the literature showing an effect of graphene oxide preparation methods on nitrogen quantity and chemical states as well as on defects and, in turn, on electrochemical sensing is non-existent. In this study, the properties of nitrogen-doped graphene materials, prepared via hydrothermal synthesis using graphite oxide produced by various classical methods using permanganate or chlorate oxidants Staudenmaier, Hummers, Hofmann and Brodie oxidation methods, were studied; the resulting nitrogen-doped graphene oxides were labeled as ST-GO, HU-GO, HO-GO and BR-GO, respectively. The electrochemical oxidation of biomolecules, such as ascorbic acid, uric acid, dopamine, nicotinamide adenine nucleotide and DNA free bases, was carried out using cyclic voltammetry and differential pulse voltammetry techniques. The nitrogen content in doped graphene oxides increased in the order ST-GO graphene followed this trend, as shown in the cyclic voltammograms. This is a very important finding that provides insight into the electrocatalytic effect of N-doped graphene. The nitrogen-doped graphene materials exhibited improved sensitivity over bare glassy carbon for ascorbic acid, uric acid and dopamine detection. These studies will enhance our understanding of the effects of graphite oxide precursors on the electrochemical sensing properties of nitrogen-doped graphene materials.

High energy beam impact tests on a LHC tertiary collimator at the CERN high-radiation to materials facility

Directory of Open Access Journals (Sweden)

Marija Cauchi

2014-02-01

Full Text Available The correct functioning of a collimation system is crucial to safely operate highly energetic particle accelerators, such as the Large Hadron Collider (LHC. The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN High-Radiation to Materials (HiRadMat facility, involved 440 GeV proton beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained, together with some first outcomes from visual inspection and a comparison of such results with numerical simulations.

High energy beam impact tests on a LHC tertiary collimator at the CERN high-radiation to materials facility

Science.gov (United States)

Cauchi, Marija; Aberle, O.; Assmann, R. W.; Bertarelli, A.; Carra, F.; Cornelis, K.; Dallocchio, A.; Deboy, D.; Lari, L.; Redaelli, S.; Rossi, A.; Salvachua, B.; Mollicone, P.; Sammut, N.

2014-02-01

The correct functioning of a collimation system is crucial to safely operate highly energetic particle accelerators, such as the Large Hadron Collider (LHC). The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN High-Radiation to Materials (HiRadMat) facility, involved 440 GeV proton beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained, together with some first outcomes from visual inspection and a comparison of such results with numerical simulations.

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.

Energetic lanthanide complexes: coordination chemistry and explosives applications

International Nuclear Information System (INIS)

Manner, V W; Barker, B J; Sanders, V E; Laintz, K E; Scott, B L; Preston, D N; Sandstrom, M; Reardon, B L

2014-01-01

Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

Structural materialization of stainless steel molds and dies by the low temperature high density plasma nitriding

Directory of Open Access Journals (Sweden)

Aizawa Tatsuhiko

2015-01-01

Full Text Available Various kinds of stainless steels have been widely utilized as a mold substrate material for injection molding and as a die for mold-stamping and direct stamping processes. Since they suffered from high temperature transients and thermal cycles in practice, they must be surface-treated by dry and wet coatings, or, by plasma nitriding. Martensitic stainless steel mold was first wet plated by the nickel phosphate (NiP, which was unstable at the high temperature stamping condition; and, was easy to crystalize or to fracture by itself. This issue of nuisance significantly lowered the productivity in fabrication of optical elements at present. In the present paper, the stainless steel mold was surface-treated by the low-temperature plasma nitriding. The nitrided layer by this surface modification had higher nitrogen solute content than 4 mass%; the maximum solid-solubility of nitrogen is usually 0.1 mass% in the equilibrium phase diagram. Owing to this solid-solution with high nitrogen concentration, the nitrided layer had high hardness of 1400 Hv within its thickness of 40 μm without any formation of nitrides after 14.4 ks plasma nitriding at 693 K. This nitrogen solid-solution treated stainless steel had thermal resistivity even at the mold-stamping conditions up to 900 K.

Undoped and doped poly(tetraphenylbenzidine) as sensitive material for an impedimetric nitrogen dioxide gas dosimeter

Energy Technology Data Exchange (ETDEWEB)

Marr, I.; Moos, R., E-mail: functional.materials@uni-bayreuth.de [Department of Functional Materials, University of Bayreuth, Bayreuth 95440 (Germany); Neumann, K.; Thelakkat, M. [Department of Macromolecular Chemistry I, Applied Functional Polymers, University of Bayreuth, Bayreuth 95440 (Germany)

2014-09-29

This article presents a nitrogen dioxide (NO{sub 2}) detecting gas dosimeter based on poly(tetraphenylbenzidine) poly(TPD) as nitrogen oxide (NO{sub x}) sensitive layer. Gas dosimeters are suitable devices to determine reliably low levels of analytes over a long period of time. During NO{sub x} exposure, the analyte molecules are accumulated irreversibly in the sensing layer of the dosimeter enhancing the conductivity of the hole conducting poly(TPD), which can be measured by impedance spectroscopy. Due to their possibility for low cost production by simple printing techniques and very good physical, photochemical, and electrochemical properties, poly(TPD)s are suitable for application in gas dosimeters operated at room temperature. We studied the effect of doping with a Co(III)-complex in combination with a conducting salt on the dosimeter behavior. Compared to the undoped material, a strong influence of the doping can be observed: the conductivity of the sensing material increases significantly, the noise of the signal decreases and an unwanted recovery of the sensor signal can be prevented, leading to a NO{sub x} detection limit <10 ppm.

Evaluating the Bulk Lorentz Factors of Outflow Material: Lessons Learned from the Extremely Energetic Outburst GRB 160625B

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuan-Zhu; Wang, Hao; Zhang, Shuai; Liang, Yun-Feng; Jin, Zhi-Ping; He, Hao-Ning; Liao, Neng-Hui; Fan, Yi-Zhong; Wei, Da-Ming, E-mail: liangyf@pmo.ac.cn, E-mail: jin@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Science, Nanjing, 210008 (China)

2017-02-10

GRB 160625B is an extremely bright outburst with well-monitored afterglow emission. The geometry-corrected energy is high, up to ∼5.2 × 10{sup 52} erg or even ∼8 × 10{sup 52} erg, rendering it the most energetic GRB prompt emission recorded so far. We analyzed the time-resolved spectra of the prompt emission and found that in some intervals there were likely thermal-radiation components and the high energy emission was characterized by significant cutoff. The bulk Lorentz factors of the outflow material are estimated accordingly. We found out that the Lorentz factors derived in the thermal-radiation model are consistent with the luminosity-Lorentz factor correlation found in other bursts, as well as in GRB 090902B for the time-resolved thermal-radiation components, while the spectral cutoff model yields much lower Lorentz factors that are in tension with the constraints set by the electron pair Compton scattering process. We then suggest that these spectral cutoffs are more likely related to the particle acceleration process and that one should be careful in estimating the Lorentz factors if the spectrum cuts at a rather low energy (e.g., ∼tens of MeV). The nature of the central engine has also been discussed, and a stellar-mass black hole is favored.

Recovery of nitrogen by spring barley following incorporation of 15N-labelled straw and catch crop material

DEFF Research Database (Denmark)

Thomsen, I.K.; Jensen, E.S.

1994-01-01

The recovery by spring barley (Hordeum vulgare L.) of nitrogen mineralized from N-15-labelled straw and ryegrass material was followed for 3 years in the field. The effects of separate and combined applications of straw and ryegrass were studied using cross-labelling with N-15. Reference plots re...... mineral fertilizer was in the second and third barley crop similar to the recovery of N from incorporated plant residues.......The recovery by spring barley (Hordeum vulgare L.) of nitrogen mineralized from N-15-labelled straw and ryegrass material was followed for 3 years in the field. The effects of separate and combined applications of straw and ryegrass were studied using cross-labelling with N-15. Reference plots...... receiving (NH4NO3)-N-15-N-15 were included. Plant samples were taken every second week until maturity during the first growing season and at maturity in the two following years. Incorporation of plant material had no significant influence on the above-ground dry matter yield of the barley. The barley...

Three-dimensional Mesoscale Simulations of Detonation Initiation in Energetic Materials with Density-based Kinetics

Science.gov (United States)

Jackson, Thomas; Jost, A. M.; Zhang, Ju; Sridharan, P.; Amadio, G.

2017-06-01

In this work we present three-dimensional mesoscale simulations of detonation initiation in energetic materials. We solve the reactive Euler equations, with the energy equation augmented by a power deposition term. The reaction rate at the mesoscale is modelled using a density-based kinetics scheme, adapted from standard Ignition and Growth models. The deposition term is based on previous results of simulations of pore collapse at the microscale, modelled at the mesoscale as hot-spots. We carry out three-dimensional mesoscale simulations of random packs of HMX crystals in a binder, and show that the transition between no-detonation and detonation depends on the number density of the hot-spots, the initial radius of the hot-spot, the post-shock pressure of an imposed shock, and the amplitude of the power deposition term. The trends of transition at lower pressure of the imposed shock for larger number density of pore observed in experiments is reproduced. Initial attempts to improve the agreement between the simulation and experiments through calibration of various parameters will also be made.

Efficient Construction of Energetic Materials via Nonmetallic Catalytic Carbon-Carbon Cleavage/Oxime-Release-Coupling Reactions.

Science.gov (United States)

Zhao, Gang; He, Chunlin; Yin, Ping; Imler, Gregory H; Parrish, Damon A; Shreeve, Jean'ne M

2018-03-14

The exploitation of C-C activation to facilitate chemical reactions is well-known in organic chemistry. Traditional strategies in homogeneous media rely upon catalyst-activated or metal-mediated C-C bonds leading to the design of new processes for applications in organic chemistry. However, activation of a C-C bond, compared with C-H bond activation, is a more challenging process and an underdeveloped area because thermodynamics does not favor insertion into a C-C bond in solution. Carbon-carbon bond cleavage through loss of an oxime moiety has not been reported. In this paper, a new observation of self-coupling via C-C bond cleavage with concomitant loss of oxime in the absence of metals (either metal-complex mediation or catalysis) results in dihydroxylammonium 5,5-bistetrazole-1,10-diolate (TKX-50) as well as N, N'-([3,3'-bi(1,2,4-oxadiazole)]-5,5'-diyl)dinitramine, a potential candidate for a new generation of energetic materials.

Very energetic photons at HERA

International Nuclear Information System (INIS)

Bawa, A.C.; Krawczyk, M.

1991-01-01

We show that every energetic photons in the backward direction can be produced in deep inelastic Compton scattering at HERA. Assuming a fixed energy of 9 GeV for the initial photons and 820 GeV for the protons a high rate is found for the production of final photons with a transverse momentum equal to 5 GeV/c and energy between 40 GeV and 300 GeV. These energetic photons arise mainly from the scattering of the soft gluonic constituents of the initial photon with quarks from the proton. They are produced in the backward direction in coincidence with a photon beam jet of energy ∝ 9 GeV in the forward direction. (orig.)

Electrical initiation of an energetic nanolaminate film

Science.gov (United States)

Tringe, Joseph W.; Gash, Alexander E.; Barbee, Jr., Troy W.

2010-03-30

A heating apparatus comprising an energetic nanolaminate film that produces heat when initiated, a power source that provides an electric current, and a control that initiates the energetic nanolaminate film by directing the electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature. Also a method of heating comprising providing an energetic nanolaminate film that produces heat when initiated, and initiating the energetic nanolaminate film by directing an electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature.

Identification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction.

Science.gov (United States)

Zitolo, Andrea; Ranjbar-Sahraie, Nastaran; Mineva, Tzonka; Li, Jingkun; Jia, Qingying; Stamatin, Serban; Harrington, George F; Lyth, Stephen Mathew; Krtil, Petr; Mukerjee, Sanjeev; Fonda, Emiliano; Jaouen, Frédéric

2017-10-16

Single-atom catalysts with full utilization of metal centers can bridge the gap between molecular and solid-state catalysis. Metal-nitrogen-carbon materials prepared via pyrolysis are promising single-atom catalysts but often also comprise metallic particles. Here, we pyrolytically synthesize a Co-N-C material only comprising atomically dispersed cobalt ions and identify with X-ray absorption spectroscopy, magnetic susceptibility measurements and density functional theory the structure and electronic state of three porphyrinic moieties, CoN 4 C 12 , CoN 3 C 10,porp and CoN 2 C 5 . The O 2 electro-reduction and operando X-ray absorption response are measured in acidic medium on Co-N-C and compared to those of a Fe-N-C catalyst prepared similarly. We show that cobalt moieties are unmodified from 0.0 to 1.0 V versus a reversible hydrogen electrode, while Fe-based moieties experience structural and electronic-state changes. On the basis of density functional theory analysis and established relationships between redox potential and O 2 -adsorption strength, we conclude that cobalt-based moieties bind O 2 too weakly for efficient O 2 reduction.Nitrogen-doped carbon materials with atomically dispersed iron or cobalt are promising for catalytic use. Here, the authors show that cobalt moieties have a higher redox potential, bind oxygen more weakly and are less active toward oxygen reduction than their iron counterpart, despite similar coordination.

Hierarchically porous nitrogen-doped carbon derived from the activation of agriculture waste by potassium hydroxide and urea for high-performance supercapacitors

Science.gov (United States)

Zou, Kaixiang; Deng, Yuanfu; Chen, Juping; Qian, Yunqian; Yang, Yuewang; Li, Yingwei; Chen, Guohua

2018-02-01

Nitrogen-doped carbon with an ultra-high specific surface area and a hierarchically interconnected porous structure is synthesized in large scale from a green route, that is, the activation of bagasse via a one-step method using KOH and urea. KOH and urea play a synergistic effect for the enhancement of the specific surface area and the modification of pore size of the as-prepared material. Benefiting from the multiple synergistic roles originated from an ultra-high specific area (2905.4 m2 g-1), a high porous volume (2.05 mL g-1 with 75.6 vol% micropores, which is an ideal proportion of micropores for obtaining high specific capacitance), a suitable nitrogen content (2.63 wt%), and partial graphitization, the hierarchically interconnected porous N-doped carbon exhibits an excellent electrochemical performance with a high specific capacitance (350.8, 301.9, and 259.5 F g-1 at 1.0 A g-1 in acidic, alkaline, and neutral electrolytes, respectively), superior rate capability and excellent cycling stability (almost no capacitance loss up to 5000 cycles). Furthermore, the symmetric device assembled by this material achieves high energy densities of 39.1 and 23.5 Wh kg-1 at power densities of 1.0 and 20 kW kg-1, respectively, and exhibits an excellent long-term cycling stability (with capacitance retention above 95.0% after 10 000 cycles).

Nitrogen Atom Energy Distributions in a Hollow-cathode Planar Sputtering Magnetron

International Nuclear Information System (INIS)

Ruzic, D.N.; Goeckner, M.J.; Cohen, S.A.; Wang, Zhehui

1999-01-01

Energy distributions of N atoms in a hollow-cathode planar sputtering magnetron were obtained by use of optical emission spectroscopy. A characteristic line, N I 8216.3 , well-separated from molecular nitrogen emission bands, was identified. Jansson's nonlinear spectral deconvolution method, refined by minimization of χ w ampersand sup2; , was used to obtain the optimal deconvolved spectra. These showed nitrogen atom energies from 1 eV to beyond 500 eV. Based on comparisons with VFTRIM results, we propose that the energetic N atoms are generated from N 2 + ions after these ions are accelerated through the sheath and dissociatively reflect from the cathode

Determination of the nitrogen vacancy as a shallow compensating center in GaN doped with divalent metals.

Science.gov (United States)

Buckeridge, J; Catlow, C R A; Scanlon, D O; Keal, T W; Sherwood, P; Miskufova, M; Walsh, A; Woodley, S M; Sokol, A A

2015-01-09

We report accurate energetics of defects introduced in GaN on doping with divalent metals, focusing on the technologically important case of Mg doping, using a model that takes into consideration both the effect of hole localization and dipolar polarization of the host material, and includes a well-defined reference level. Defect formation and ionization energies show that divalent dopants are counterbalanced in GaN by nitrogen vacancies and not by holes, which explains both the difficulty in achieving p-type conductivity in GaN and the associated major spectroscopic features, including the ubiquitous 3.46 eV photoluminescence line, a characteristic of all lightly divalent-metal-doped GaN materials that has also been shown to occur in pure GaN samples. Our results give a comprehensive explanation for the observed behavior of GaN doped with low concentrations of divalent metals in good agreement with relevant experiment.

Determination of the Nitrogen Vacancy as a Shallow Compensating Center in GaN Doped with Divalent Metals

Science.gov (United States)

Buckeridge, J.; Catlow, C. R. A.; Scanlon, D. O.; Keal, T. W.; Sherwood, P.; Miskufova, M.; Walsh, A.; Woodley, S. M.; Sokol, A. A.

2015-01-01

We report accurate energetics of defects introduced in GaN on doping with divalent metals, focusing on the technologically important case of Mg doping, using a model that takes into consideration both the effect of hole localization and dipolar polarization of the host material, and includes a well-defined reference level. Defect formation and ionization energies show that divalent dopants are counterbalanced in GaN by nitrogen vacancies and not by holes, which explains both the difficulty in achieving p -type conductivity in GaN and the associated major spectroscopic features, including the ubiquitous 3.46 eV photoluminescence line, a characteristic of all lightly divalent-metal-doped GaN materials that has also been shown to occur in pure GaN samples. Our results give a comprehensive explanation for the observed behavior of GaN doped with low concentrations of divalent metals in good agreement with relevant experiment.

Heavily nitrogen doped, graphene supercapacitor from silk cocoon

International Nuclear Information System (INIS)

Sahu, Vikrant; Grover, Sonia; Tulachan, Brindan; Sharma, Meenakshi; Srivastava, Gaurav; Roy, Manas; Saxena, Manav; Sethy, Niroj; Bhargava, Kalpana; Philip, Deepu; Kim, Hansung; Singh, Gurmeet; Singh, Sushil Kumar; Das, Mainak; Sharma, Raj Kishore

2015-01-01

Doping of graphene with nitrogen is of much interest, since it improves the overall conductivity and supercapacitive properties. Besides conductivity, nitrogen doping also enhances the pseudo-capacitance due to fast and reversible surface redox processes. In this work, we have developed a cheap and easy process for synthesizing heavily nitrogen doped graphene (15% nitrogen) from non-mulberry silk cocoon membrane (Tassar, Antheraea mylitta) by pyrolyzing the cocoon at 400 °C in argon atmosphere. Further we have investigated the performance of this heavily ‘nitrogen doped graphene’ (NDG) in a supercapacitor device. Our results suggest that NDG obtained from cocoon has improved supercapacitor performance. The improved performance is due to the high electronegativity of nitrogen that forms dipoles on the graphene surface. These dipoles consequently enhance the tendency of graphene to attract charged species to its surface. This is a green and clean synthesis approach for developing electronic materials for energy applications

Nitrogen Removal by Anammox Biofilm Column Reactor at Moderately Low Temperature

Directory of Open Access Journals (Sweden)

Tuty Emilia Agustina

2017-10-01

Full Text Available The anaerobic ammonium oxidation (anammox as a new biological approach for nitrogen removal has been considered to be more cost-effective compared with the combination of nitrification and denitrification process. However, the anammox bioreactors are mostly explored at high temperature (>300C in which temperature controlling system is fully required. This research was intended to develop and to apply anammox process for high nitrogen concentration removal at ambient temperature used for treating wastewater in tropical countries. An up-flow biofilm column reactor, which the upper part constructed with a porous polyester non-woven fabric material as a carrier to attach the anammox bacteria was operated without heating system. A maximum nitrogen removal rate (NRR of 1.05 kg-N m3 d-1 was reached in the operation days of 178 with a Total Nitrogen (TN removal efficiency of 74%. This showed the biofilm column anammox reactor was successfully applied to moderate high nitrogen removal from synthetic wastewater at moderately low temperature. Keywords: Anammox, biofilm column reactor, ambient temperature, nitrogen removal

Fabrication of spherical high-nitrogen stainless steel powder alloys by mechanical alloying and thermal plasma spheroidization

Science.gov (United States)

Razumov, Nikolay G.; Wang, Qing Sheng; Popovich, Anatoly A.; Shamshurin, Aleksey I.

2018-04-01

This paper describes the results of experimental studies on the treatment of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, synthesized by the mechanical alloying (MA) of elemental powders in the flow of a radio frequency thermal plasma. The as-milled powder with irregular particles were successfully converted into spherical high-nitrogen stainless steel powder alloy. Measurement of the residual nitrogen content in the obtained powder, shown that during the plasma spheroidization process, part of the nitrogen escapes from the alloy.

Energetic Particles Dynamics in Mercury's Magnetosphere

Science.gov (United States)

Walsh, Brian M.; Ryou, A.S.; Sibeck, D. G.; Alexeev, I. I.

2013-01-01

We investigate the drift paths of energetic particles in Mercury's magnetosphere by tracing their motion through a model magnetic field. Test particle simulations solving the full Lorentz force show a quasi-trapped energetic particle population that gradient and curvature drift around the planet via "Shabansky" orbits, passing though high latitudes in the compressed dayside by equatorial latitudes on the nightside. Due to their large gyroradii, energetic H+ and Na+ ions will typically collide with the planet or the magnetopause and will not be able to complete a full drift orbit. These simulations provide direct comparison for recent spacecraft measurements from MESSENGER. Mercury's offset dipole results in an asymmetric loss cone and therefore an asymmetry in particle precipitation with more particles precipitating in the southern hemisphere. Since the planet lacks an atmosphere, precipitating particles will collide directly with the surface of the planet. The incident charged particles can kick up neutrals from the surface and have implications for the formation of the exosphere and weathering of the surface

Tunable rare-earth fcu-MOFs: A platform for systematic enhancement of CO2 adsorption energetics and uptake

KAUST Repository

Xue, Dongxu

2013-05-22

A series of fcu-MOFs based on rare-earth (RE) metals and linear fluorinated/nonfluorinated, homo/heterofunctional ligands were targeted and synthesized. This particular fcu-MOF platform was selected because of its unique structural characteristics combined with the ability/potential to dictate and regulate its chemical properties (e.g., tuning of the electron-rich RE metal ions and high localized charge density, a property arising from the proximal positioning of polarizing tetrazolate moieties and fluoro-groups that decorate the exposed inner surfaces of the confined conical cavities). These features permitted a systematic gas sorption study to evaluate/elucidate the effects of distinctive parameters on CO2-MOF sorption energetics. Our study supports the importance of the synergistic effect of exposed open metal sites and proximal highly localized charge density toward materials with enhanced CO2 sorption energetics. © 2013 American Chemical Society.

Energetic M1 transitions as a probe of nuclear collectivity at high temperatures

International Nuclear Information System (INIS)

Baktash, C.

1987-01-01

At ORNL, we have recently utilized the Spin Spectrometer setup to investigate the differential effects of increasing spin and excitation energy on nuclear shape and collectivity in 158 Yb. Along the yrast line of this and other N = 88 nuclei, weakly prolate shapes gradually give way to triaxial, and then finally to non-collective oblate shapes as the spin approaches 40 h-bar. However, above the yrast line, large deformation and collectivity once again sets in. This is evidenced by the emergence of a broad quadrupole structure (E/sub γ/ ≅ 1.2 MeV) in the continuum gamma-ray spectra that grows with increasing temperature. The short (sub ps) lifetimes of these transitions attest to the collective nature of these structures. The emergence and growth of the quadrupole structure at high excitation energies is closely correlated with the appearance of energetic (E/sub γ/ ≅ 2.5 MeV), fast M1 transitions which form another broad structure in the continuum spectra. From the centroid of the M1 bump, a quadrupole deformation parameter of 0.35 is inferred. Because of this sensitivity, these energetic M1 transitions provide a unique probe of nuclear shape in the excitation energy range of ≅ 3 to 10 MeV. 6 refs., 2 figs

Structure and energetics of nanotwins in cubic boron nitrides

Energy Technology Data Exchange (ETDEWEB)

Zheng, Shijian, E-mail: sjzheng@imr.ac.cn, E-mail: zrf@buaa.edu.cn; Ma, Xiuliang [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, Ruifeng, E-mail: sjzheng@imr.ac.cn, E-mail: zrf@buaa.edu.cn [School of Materials Science and Engineering, and International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191 (China); Huang, Rong [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200062 (China); Taniguchi, Takashi [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Ikuhara, Yuichi [Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587 (Japan); Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656 (Japan); Beyerlein, Irene J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-08-22

Recently, nanotwinned cubic boron nitrides (NT c-BN) have demonstrated extraordinary leaps in hardness. However, an understanding of the underlying mechanisms that enable nanotwins to give orders of magnitude increases in material hardness is still lacking. Here, using transmission electron microscopy, we report that the defect density of twin boundaries depends on nanotwin thickness, becoming defect-free, and hence more stable, as it decreases below 5 nm. Using ab initio density functional theory calculations, we reveal that the Shockley partials, which may dominate plastic deformation in c-BNs, show a high energetic barrier. We also report that the c-BN twin boundary has an asymmetrically charged electronic structure that would resist migration of the twin boundary under stress. These results provide important insight into possible nanotwin hardening mechanisms in c-BN, as well as how to design these nanostructured materials to reach their full potential in hardness and strength.

Conditioning ad energetic utilization of wooden materials for landscape conservation; Aufbereitung und Energetische Nutzung von holzigem Landschaftspflegematerial

Energy Technology Data Exchange (ETDEWEB)

Letalik, Christian [C.A.R.M.E.N. e.V., Straubing (Germany). Abt. Festbrennstoffe

2013-10-01

It has become common practice to energetically recover ligneous materials from landscape conservation activities in heat (and power) generation plants. The treatment of green cuttings along roads, railways or power supply lines is state of the art. Such landscaping materials are ligneous green residues e.g. from tree lopping in orchard meadows or shrub hedges - there are about 45,000 kilometers of hedgerows in Schleswig-Holstein, Germany, alone. Shredder machines disintegrate the materials into any required size. By means of adjustable perforated baskets on the disintegrating engine and subsequent sieving steps, homogenous fuels of defined dimensions and low shares of fines can be provided, whichever required. Depending on the water content, such wood chips contain about 20% less energy (calorific value) than comparable forest wood chips. It is important, however, that mineral fine particles like sand, soil or small stones are being sieved out before the combustion because they do not only decrease the calorific value and hence the boiler performance but also cause problems in the combustion areas resulting in higher costs for maintenance, cleaning and ash utilization. Composting plants are regularly well-equipped. They use well-proven management concepts for the material flow to merely condition as much landscape cuttings into fuels, enable the aerobe composting process with less ligneous and more humid materials to continue. For both compost and wood fuels there is sufficient demand resulting in increasing revenues. The EEG amendment 2012 classifies landscape conservation materials as raw materials of remuneration class II (= 8 ct/kWhel on top of the basic remuneration). This is likely to further increment the demand for ligneous fuel from landscape conservation. According to the EEG 2012 there will no longer be power plants without reasonable heat concepts. (orig.)

About Russian nuclear energetic perspectives

International Nuclear Information System (INIS)

Laletin, N.I.

2003-01-01

My particular view about Russian nuclear energetics perspectives is presented. The nearest and the further perspectives are considered. The arguments are adduced that the most probable scenario of nuclear energetic development is its stabilization in the near future. Fur further development the arguments of supporters and opponents of nuclear energetics are analyzed. Three points of view are considered. The first point of view that there is not alternative for nuclear energetics. My notes are the following ones. a) I express a skeptic opinion about a statement of quick exhaustion of fossil organic fuel recourses and corresponding estimations are presented. b) It is expressed skeptic opinion about the statement that nuclear energetics can have a visual influence on ''steam effect''. c) I agree that nuclear energetics is the most ecological technology for normal work but however we can't disregard possibilities of catastrophic accidents. The second point of view that the use of nuclear energetics can't have the justification. I adduce the arguments contrary to this statement. The third point of view that nuclear energetics is a usual technology and the only criteria for discussions about what dimension and where one ought develop it is total cost of its unit. Expressed an opinion that the deceived for the choose of a way the skill of the estimate correctly and optimized so named the external parts of the unit energy costs for different energy technologies. (author)

Measurement of electron emission due to energetic ion bombardment in plasma source ion implantation

Science.gov (United States)

Shamim, M. M.; Scheuer, J. T.; Fetherston, R. P.; Conrad, J. R.

1991-11-01

An experimental procedure has been developed to measure electron emission due to energetic ion bombardment during plasma source ion implantation. Spherical targets of copper, stainless steel, graphite, titanium alloy, and aluminum alloy were biased negatively to 20, 30, and 40 kV in argon and nitrogen plasmas. A Langmuir probe was used to detect the propagating sheath edge and a Rogowski transformer was used to measure the current to the target. The measurements of electron emission coefficients compare well with those measured under similar conditions.

Electrochemically fabricated polypyrrole-cobalt-oxygen coordination complex as high-performance lithium-storage materials.

Science.gov (United States)

Guo, Bingkun; Kong, Qingyu; Zhu, Ying; Mao, Ya; Wang, Zhaoxiang; Wan, Meixiang; Chen, Liquan

2011-12-23

Current lithium-ion battery (LIB) technologies are all based on inorganic electrode materials, though organic materials have been used as electrodes for years. Disadvantages such as limited thermal stability and low specific capacity hinder their applications. On the other hand, the transition metal oxides that provide high lithium-storage capacity by way of electrochemical conversion reaction suffer from poor cycling stability. Here we report a novel high-performance, organic, lithium-storage material, a polypyrrole-cobalt-oxygen (PPy-Co-O) coordination complex, with high lithium-storage capacity and excellent cycling stability. Extended X-ray absorption fine structure and Raman spectroscopy and other physical and electrochemical characterizations demonstrate that this coordination complex can be electrochemically fabricated by cycling PPy-coated Co(3)O(4) between 0.0 V and 3.0 V versus Li(+)/Li. Density functional theory (DFT) calculations indicate that each cobalt atom coordinates with two nitrogen atoms within the PPy-Co coordination layer and the layers are connected with oxygen atoms between them. Coordination weakens the C-H bonds on PPy and makes the complex a novel lithium-storage material with high capacity and high cycling stability. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selection of materials for ETF

International Nuclear Information System (INIS)

Nygren, R.E.

1980-01-01

Repeated operation of a long burning, ignited plasma in ETF implies high exposure to an intense source of energetic particles and high energy (14.1 MeV) neutrons and presents a unique environment for materials in ETF compared with earlier tokamaks. Designing ETF (and FED) will provide many insights into reactor relevant design issues related to materials performance, particularly in components outside the first wall. This paper focuses primarily on how exposure to the plasma and radiation damage to materials infuence the design lifetime of particular components, including the first wall, armor, and TF coils. Also discussed are radiaton exposure limits for repair welding of the torus and for electrical materials used in RF and diagnostics

Nanocomposites for controlled release of nitrogen fertilizer

International Nuclear Information System (INIS)

Silva, Viviane J.M. da; Visconte, Leila L.Y.; Nascimento, Regina Sandra V.

2009-01-01

The study aimed at the development of nano structured materials capable of reducing the rate of release of nitrogen in the soil from an agricultural nitrogen fertilizer. Four different systems of polymer composites were prepared: (1) montmorillonite clay/fertilizer, (2) montmorillonite clay/thermoplastic starch and fertilizer, (3) montmorillonite clay/fertilizer, thermoplastic starch and low-density polyethylene (LDPE) and also (4) montmorillonite clay/fertilizer, thermoplastic starch and polycaprolactone. It was confirmed the formation of nano structured materials by elemental analysis (CHN) and X-ray diffraction (XRD). The kinetics of nitrogen release was detected by enzymatic colorimetric analysis and spectroscopy in the ultraviolet/visible. The results showed that all materials evaluated were able to reduce the rate of release of nitrogen in the fertilizers. (author)

Molecular approaches to solar energy conversion: the energetic cost of charge separation from molecular-excited states.

Science.gov (United States)

Durrant, James R

2013-08-13

This review starts with a brief overview of the technological potential of molecular-based solar cell technologies. It then goes on to focus on the core scientific challenge associated with using molecular light-absorbing materials for solar energy conversion, namely the separation of short-lived, molecular-excited states into sufficiently long-lived, energetic, separated charges capable of generating an external photocurrent. Comparisons are made between different molecular-based solar cell technologies, with particular focus on the function of dye-sensitized photoelectrochemical solar cells as well as parallels with the function of photosynthetic reaction centres. The core theme of this review is that generating charge carriers with sufficient lifetime and a high quantum yield from molecular-excited states comes at a significant energetic cost-such that the energy stored in these charge-separated states is typically substantially less than the energy of the initially generated excited state. The role of this energetic loss in limiting the efficiency of solar energy conversion by such devices is emphasized, and strategies to minimize this energy loss are compared and contrasted.

Nitrogen-doped hierarchical lamellar porous carbon synthesized from the fish scale as support material for platinum nanoparticle electrocatalyst toward the oxygen reduction reaction.

Science.gov (United States)

Liu, Haijing; Cao, Yinliang; Wang, Feng; Huang, Yaqin

2014-01-22

Novel hierarchical lamellar porous carbon (HLPC) with high BET specific surface area of 2730 m(2) g(-1) and doped by nitrogen atoms has been synthesized from the fish scale without any post-synthesis treatment, and applied to support the platinum (Pt) nanoparticle (NP) catalysts (Pt/HLPC). The Pt NPs could be highly dispersed on the porous surface of HLPC with a narrow size distribution centered at ca. 2.0 nm. The results of the electrochemical analysis reveal that the electrochemical active surface area (ECSA) of Pt/HLPC is larger than the Pt NP electrocatalyst supported on the carbon black (Pt/Vulcan XC-72). Compared with the Pt/Vulcan XC-72, the Pt/HLPC exhibits larger current density, lower overpotential, and enhanced catalytic activity toward the oxygen reduction reaction (ORR) through the direct four-electron pathway. The improved catalytic activity is mainly attributed to the high BET specific surface area, hierarchical porous structures and the nitrogen-doped surface property of HLPC, indicating the superiority of HLPC as a promising support material for the ORR electrocatalysts.

The source of multi spectral energy of solar energetic electron

Energy Technology Data Exchange (ETDEWEB)

Herdiwijaya, Dhani [Astronomy Division and Bosscha Observatory, Faculty Mathematics and Natural Sciences, Intitute Technology of Bandung, Ganesha 10, Bandung, Indonesia 40132 dhani@as.itb.ac.id (Indonesia)

2015-04-16

We study the solar energetic electron distribution obtained from ACE and GOES satellites which have different altitudes and electron spectral energy during the year 1997 to 2011. The electron spectral energies were 0.038–0.315 MeV from EPAM instrument onboard ACE satellite and >2 MeV from GOES satellite. We found that the low electron energy has no correlation with high energy. In spite of we have corrected to the altitude differences. It implied that they originated from time dependent events with different sources and physical processes at the solar atmosphere. The sources of multi spectral energetic electron were related to flare and CME phenomena. However, we also found that high energetic electron comes from coronal hole.

Analysis of the energetic sector through the national energetic matrix

International Nuclear Information System (INIS)

Garzon Lozano, Enrique

2007-01-01

The author shows the results of the national energetic balance 1975-2005, through the energetic matrix of the country, giving an annual growth of 5.1% in this period of offer of primary energy, where the mineral coal participates with 9,6%, the hydraulic energy with 4,8%, natural gas with 4,2%, trash with 2,4% and petroleum with 2,2%, while the firewood fell in 0,5%

Solar-wind interactions with the Moon: nature and composition of nitrogen compounds

International Nuclear Information System (INIS)

Mukherjee, N.R.

1981-01-01

The lunar atmosphere and magnetic field are very tenuous. The solar wind, therefore, interacts directly with the lunar surface material and the dominant nature of interaction is essentially complete absorption of solar-wind particles by the surface material resulting in no upstream bowshock, but a cavity downstream. The solar-wind nitrogen ion species induce and undergo a complex set of reactions with the elements of lunar material and the solar-wind-derived trapped elements. The nitrogen concentration indigeneous to the lunar surface material is practically nil. Therefore any nitrogen and nitrogen compounds found in the lunar surface material are due to the solar-wind implantation of nitrogen ions. The flux of the solar-wind nitrogen ion species is about 6 X 10 3 cm -2 s -1 . Since there is no evidence for accumulation of nitrogen species in the lunar surface material, the outflux of nitrogen species from the lunar material to the atmosphere is the same as the solar-wind nitrogen ion flux. The species of the outflux are primarily NO and NH 3 , and their respective concentrations in the near surface lunar atmosphere are found to be 327 and 295 cm -3 . (Auth.)

Streaming reversal of energetic particles in the magnetotail during a substorm

Science.gov (United States)

Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.; Akasofu, S.-I.

1984-01-01

A case of reversal in the streaming anisotropy of energetic ions and in the plasma flow observed from the IMP 8 spacecraft during a substorm on February 8, 1978 is studied in detail using measurements of energetic particles, plasma, and magnetic field. Four new features emerge when high time resolution data are examined in detail. The times of streaming reversal of energetic particles in different energy ranges do not coincide with the time of plasma flow reversal. Qualitatively different velocity distributions are observed in earthward and tailward plasma flows during the observed flow reversal intervals. Strong tailward streaming of energetic particles can be detected during northward magnetic field environments and, conversely, earthward streaming in southward field environments. During the period of tailward streaming of energetic particles, earthward streaming fluxes are occasionally detected.

A review on nickel-free nitrogen containing austenitic stainless steels for biomedical applications.

Science.gov (United States)

Talha, Mohd; Behera, C K; Sinha, O P

2013-10-01

The field of biomaterials has become a vital area, as these materials can enhance the quality and longevity of human life. Metallic materials are often used as biomaterials to replace structural components of the human body. Stainless steels, cobalt-chromium alloys, commercially pure titanium and its alloys are typical metallic biomaterials that are being used for implant devices. Stainless steels have been widely used as biomaterials because of their very low cost as compared to other metallic materials, good mechanical and corrosion resistant properties and adequate biocompatibility. However, the adverse effects of nickel ions being released into the human body have promoted the development of "nickel-free nitrogen containing austenitic stainless steels" for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel and emphatically the advantages of nitrogen in stainless steel, as well as the development of nickel-free nitrogen containing stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength, better corrosion and wear resistance and superior biocompatibility in comparison to the currently used austenitic stainless steel (e.g. 316L), the newly developed nickel-free high nitrogen austenitic stainless steel is a reliable substitute for the conventionally used medical stainless steels. Copyright © 2013 Elsevier B.V. All rights reserved.

Positron lifetime study of copper irradiated by energetic protons or energetic neutrons

International Nuclear Information System (INIS)

Howell, R.H.

1979-03-01

Positron lifetime measurements of pure copper damaged by irradiation with energetic protons and neutrons are presented. Lifetime determinations of the bulk material and various traps were made, and the dependence of the trapping rate on dose and irradiation energy were investigated. The results from the neutron- and proton-irradiated samples point to the existence of traps with similar but distinct lifetime parameters, not varying greatly from values reported in deformation studies. Also, a trap with long lifetime is seen for some proton irradiations, but is never seen for the neutron irradiations. The trapping rate of the short-lifetime trap is a linear function of dose for proton-irradiated samples and nearly so for the neutron irradiation. 1 figure

Carbon and nitrogen isotopic signatures and nitrogen profile to identify adulteration in organic fertilizers.

Science.gov (United States)

Verenitch, Sergei; Mazumder, Asit

2012-08-29

Recently it has been shown that stable isotopes of nitrogen can be used to discriminate between organic and synthetic fertilizers, but the robustness of the approach is questionable. This work developed a comprehensive method that is far more robust in identifying an adulteration of organic nitrogen fertilizers. Organic fertilizers of various types (manures, composts, blood meal, bone meal, fish meal, products of poultry and plant productions, molasses and seaweed based, and others) available on the North American market were analyzed to reveal the most sensitive criteria as well as their quantitative ranges, which can be used in their authentication. Organic nitrogen fertilizers of known origins with a wide δ(15)N range between -0.55 and 28.85‰ (n = 1258) were characterized for C and N content, δ(13)C, δ(15)N, viscosity, pH, and nitrogen profile (urea, ammonia, organic N, water insoluble N, and NO3). A statistically significant data set of characterized unique organic nitrogen fertilizers (n = 335) of various known origins has been assembled. Deliberately adulterated samples of different types of organic fertilizers mixed with synthetic fertilizers at a wide range of proportions have been used to develop the quantitative critical characteristics of organic fertilizers as the key indicators of their adulteration. Statistical analysis based on the discriminant functions of the quantitative critical characteristics of organic nitrogen fertilizers from 14 different source materials revealed a very high average rate of correct classification. The developed methodology has been successfully used as a source identification tool for numerous commercial nitrogen fertilizers available on the North American market.

Bioaccumulation of chemical warfare agents, energetic materials, and metals in deep-sea shrimp from discarded military munitions sites off Pearl Harbor

Science.gov (United States)

Koide, Shelby; Silva, Jeff A. K.; Dupra, Vilma; Edwards, Margo

2016-06-01

The bioaccumulation of munitions-related chemicals at former military deep-water disposal sites is poorly understood. This paper presents the results of human-food-item biota sampling to assess the potential for bioaccumulation of chemical warfare agents, energetic materials, arsenic, and additional munitions-related metals in deep-sea shrimp tissue samples collected during the Hawai'i Undersea Military Munitions Assessment (HUMMA) project to date. The HUMMA investigation area is located within a former munitions sea-disposal site located south of Pearl Harbor on the island of O'ahu, Hawai'i, designated site Hawaii-05 (HI-05) by the United States Department of Defense. Indigenous deep-sea shrimp (Heterocarpus ensifer) were caught adjacent to discarded military munitions (DMM) and at control sites where munitions were absent. Tissue analysis results showed that chemical warfare agents and their degradation products were not present within the edible portions of these samples at detectable concentrations, and energetic materials and their degradation products were detected in only a few samples at concentrations below the laboratory reporting limits. Likewise, arsenic, copper, and lead concentrations were below the United States Food and Drug Administration's permitted concentrations of metals in marine biota tissue (if defined), and their presence within these samples could not be attributed to the presence of DMM within the study area based on a comparative analysis of munitions-adjacent and control samples collected. Based on this current dataset, it can be concluded that DMM existing within the HUMMA study area is not contributing to the bioaccumulation of munitions-related chemicals for the biota species investigated to date.

Hydrothermal synthesis of NiCo{sub 2}O{sub 4} nanowires/nitrogen-doped graphene for high-performance supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Yu, Mei, E-mail: yumei@buaa.edu.cn; Chen, Jianpeng; Ma, Yuxiao; Zhang, Jingdan; Liu, Jianhua; Li, Songmei; An, Junwei

2014-09-30

Highlights: • NCO/NG composites were synthesized in a water–glycerol mixed solvent via hydrothermal treatment and subsequent calcination. • NiCo{sub 2}O{sub 4} nanowires are dispersed on NG nanosheets and the composite has porous structure. • The NCO/NG composite exhibits a high specific capacitance and long cycling performance. - Abstract: NiCo{sub 2}O{sub 4} nanowires/nitrogen-doped graphene (NCO/NG) composite materials were synthesized by hydrothermal treatment in a water–glycerol mixed solvent and subsequent thermal transformation. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The electrochemical performance of the composites was evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrum techniques. NiCo{sub 2}O{sub 4} nanowires are densely coated by nitrogen-doped graphene and the composite displays good electrochemical performance. The maximum specific capacitance of NCO/NG is 1273.13 F g{sup −1} at 0.5 A g{sup −1} in 6 M KOH aqueous solution, and it exhibits good capacity retention without noticeable degradation after 3000 cycles at 4 A g{sup −1}.

Effect of Trapped Energetic Ions on MHD Activity in Spherical Tori

International Nuclear Information System (INIS)

White, R.B.; Kolesnichenko, Ya.I.; Lutsenko, V.V.; Marchenko, V.S.

2002-01-01

It is shown that the increase of beta (the ratio of plasma pressure to the magnetic field pressure) may change the character of the influence of trapped energetic ions on MHD stability in spherical tori. Namely, the energetic ions, which stabilize MHD modes (such as the ideal-kink mode, collisionless tearing mode, and semi-collisional tearing mode) at low beta, have a destabilizing influence at high beta unless the radial distribution of the energetic ions is very peaked

Mechanical characterization of selected adhesives and bulk materials at liquid nitrogen and room temperatures

International Nuclear Information System (INIS)

Fitzpatrick, C.M.; Stoddart, W.C.T.

1977-01-01

This paper presents the results of a series of mechanical tests on selected adhesives and bulk materials. The materials tested are of general interest to designers of magnets for cryogenic service and include several epoxies, a varnish, a B-stage glass cloth, insulation papers, and commercially available fiber-reinforced composites. These tests were performed at room temperature (293 K) and at liquid nitrogen temperature (77 K). The tests include both simple tension tests and lap shear tests with various adherends. The parameters critical to tensile or bond strength were varied as part of the test program. The procedures used to manufacture and test these specimens and the results of the tests are reported in this paper

Ex-Vessel corium coolability and steam explosion energetics in nordic light water reactors

International Nuclear Information System (INIS)

Dinh, T.N.; Ma, W.M.; Karbojian, A.; Kudinov, P.; Tran, C.T.; Hansson, C.R.

2008-03-01

This report presents advances and insights from the KTH's study on corium pool heat transfer in the BWR lower head; debris bed formation; steam explosion energetics; thermal hydraulics and coolability in bottom-fed and heterogeneous debris beds. Specifically, for analysis of heat transfer in a BWR lower plenum an advanced threedimensional simulation tool was developed and validated, using a so-called effective convectivity approach and Fluent code platform. An assessment of corium retention and coolability in the reactor pressure vessel (RPV) lower plenum by means of water supplied through the Control Rod Guide Tube (CRGT) cooling system was performed. Simulant material melt experiments were performed in an intermediate temperature range (1300-1600K) on DEFOR test facility to study formation of debris beds in high and low subcooled water pools characteristic of in-vessel and ex-vessel conditions. Results of the DEFOR-E scoping experiments and related analyses strongly suggest that porous beds formed in ex-vessel from a fragmented high-temperature debris is far from homogeneous. Calculation results of bed thermal hydraulics and dryout heat flux with a two-dimensional thermal-hydraulic code give the first basis to evaluate the extent by which macro and micro inhomogeneity can enhance the bed coolability. The development and validation of a model for two-phase natural circulation through a heated porous medium and its application to the coolability analysis of bottom-fed beds enables quantification of the significant effect of dryout heat flux enhancement (by a factor of 80-160%) due to bottom coolant injection. For a qualitative and quantitative understanding of steam explosion, the SHARP system and its image processing methodology were used to characterize the dynamics of a hot liquid (melt) drop fragmentation and the volatile liquid (coolant) vaporization. The experimental results provide a basis to suggest that the melt drop preconditioning is instrumental to the

Ex-Vessel corium coolability and steam explosion energetics in nordic light water reactors

Energy Technology Data Exchange (ETDEWEB)

Dinh, T.N.; Ma, W.M.; Karbojian, A.; Kudinov, P.; Tran, C.T.; Hansson, C.R. [Royal Institute of Technology (KTH), (Sweden)

2008-03-15

This report presents advances and insights from the KTH's study on corium pool heat transfer in the BWR lower head; debris bed formation; steam explosion energetics; thermal hydraulics and coolability in bottom-fed and heterogeneous debris beds. Specifically, for analysis of heat transfer in a BWR lower plenum an advanced threedimensional simulation tool was developed and validated, using a so-called effective convectivity approach and Fluent code platform. An assessment of corium retention and coolability in the reactor pressure vessel (RPV) lower plenum by means of water supplied through the Control Rod Guide Tube (CRGT) cooling system was performed. Simulant material melt experiments were performed in an intermediate temperature range (1300-1600K) on DEFOR test facility to study formation of debris beds in high and low subcooled water pools characteristic of in-vessel and ex-vessel conditions. Results of the DEFOR-E scoping experiments and related analyses strongly suggest that porous beds formed in ex-vessel from a fragmented high-temperature debris is far from homogeneous. Calculation results of bed thermal hydraulics and dryout heat flux with a two-dimensional thermal-hydraulic code give the first basis to evaluate the extent by which macro and micro inhomogeneity can enhance the bed coolability. The development and validation of a model for two-phase natural circulation through a heated porous medium and its application to the coolability analysis of bottom-fed beds enables quantification of the significant effect of dryout heat flux enhancement (by a factor of 80-160%) due to bottom coolant injection. For a qualitative and quantitative understanding of steam explosion, the SHARP system and its image processing methodology were used to characterize the dynamics of a hot liquid (melt) drop fragmentation and the volatile liquid (coolant) vaporization. The experimental results provide a basis to suggest that the melt drop preconditioning is instrumental to

Surface characterization of an energetic material, pentaerythritoltetranitrate (PETN), having a thin coating achieved through a starved addition microencapsulation technique

Energy Technology Data Exchange (ETDEWEB)

Worley, C.M.

1986-05-07

The objective of this research was to: (1) determine the nature of a thin coating on an explosive material which was applied using a starved addition microencapsulation technique, (2) understand the coating/crystal bond, and (3) investigate the wettability/adhesion of plastic/solvent combinations using the coating process. The coating used in this work was a Firestone Plastic Company copolymer (FPC-461) of vinylchloride/trifluorochloroethylene in a 1.5/1.0 weight ratio. The energetic explosive examined was pentaerythritoltetranitrate (PETN). The coating process used was starved addition followed by a solvent evaporation technique. Surface analytical studies, completed for characterization of the coating process, show (1) evidence that the polymer coating is present, but not continuous, over the surface of PETN; (2) the average thickness of the polymer coating is between 16-32 A and greater than 44 A, respectively, for 0.5 and 20 wt % coated PETN; (3) no changes in surface chemistry of the polymer or the explosive material following microencapsulation; and (4) the presence of explosive material on the surface of 0.5 wt % FPC-461 coated explosives. 5 refs., 15 figs., 6 tabs.

Multi-body forces and the energetics of transition metals, alloys, and semiconductors

International Nuclear Information System (INIS)

Carlsson, A.E.

1992-01-01

Progress over the past year is divided into 3 areas: potential-energy functions for transition-metal aluminides; electronic structure and energetics of complex structures and quasicrystals; and ceramic materials (PdO, PtO)

Industrial plants for production of highly enriched nitrogen-15

International Nuclear Information System (INIS)

Krell, E.; Jonas, C.

1977-01-01

A discussion is presented of the present stage of development of large-scale enrichment of 15 N. The most important processes utilized to separate nitrogen isotopes, namely chemical exchange in the NO/NO 2 /HNO 3 system and low-temperature distillation of NO at -151 0 C, are compared, especially with respect to their economics and use of energy. As examples, chemical exchange plants in the GDR are discussed, and the research activities necessary to optimize the process, especially to solve aerodynamic, hydrodynamic, interface and processing problems, are reviewed. Good results were obtained by the choice of an optimum location and the design of a plant for pre-enrichment to 10 at.% 15 N and an automatically operating two-section cascade for the high enrichment of 15 N to more than 99 at.%. The chemical industry has taken over operation of the plant with the consequence that the raw materials are all available without additional transport. All by-products (nitrous gases and sulphuric acid) are returned for use elsewhere within the industry. The technology of the plant has been chosen so that the quantity of highly enriched product can be varied within a wide range. The final product is used to synthesize more than 250 different 15 N-labelled compounds which are also produced on an industrial scale. (author)

Resistive interchange mode destabilized by helically trapped energetic ions and its effects on energetic ions and bulk plasmas

International Nuclear Information System (INIS)

Du, X.D.; Toi, K.; Osakabe, M.

2014-10-01

A resistive interchange mode with bursting behavior and rapid frequency chirping in the range less than 10 kHz is observed for the first time in the magnetic hill region of net current-free, low beta LHD (Large Helical Device) plasmas during high power injection of perpendicular neutral beams. The mode resonates with the precession motion of helically trapped energetic beam ions, following the resonant condition. The radial mode structure is found to be very similar to that of usual pressure-driven interchange mode, of which radial displacement eigenfunction has an even function around the rational surface. This beam driven mode is excited when the beta value of helically trapped energetic ions exceed a certain threshold. The radial transport of helically trapped energetic ions induced by the mode transiently generates significant radial electric field near the plasma peripheral region. Thus generated radial electric field clearly suppresses micro turbulence and improves bulk plasma confinement, suggesting strong flow shear generation. (author)

Distribution of nitrogen in nature and its separation

International Nuclear Information System (INIS)

Nitzsche, H.M.; Haendel, D.; Muehle, K.

1981-01-01

Proceeding from a survey on nitrogen in the atmosphere, biosphere, hydrosphere, and lithosphere and nitrogen determination methods, a detailed review is given of procedures that allow to transform any nitrogen-containing starting material into molecular nitrogen for mass spectroscopic isotope analysis

Flare energetics

Science.gov (United States)

Wu, S. T.; Dejager, C.; Dennis, B. R.; Hudson, H. S.; Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner, M. E.; Cargill, P. J.

1986-01-01

In this investigation of flare energetics, researchers sought to establish a comprehensive and self-consistent picture of the sources and transport of energy within a flare. To achieve this goal, they chose five flares in 1980 that were well observed with instruments on the Solar Maximum Mission, and with other space-borne and ground-based instruments. The events were chosen to represent various types of flares. Details of the observations available for them and the corresponding physical parameters derived from these data are presented. The flares were studied from two perspectives, the impulsive and gradual phases, and then the results were compared to obtain the overall picture of the energics of these flares. The role that modeling can play in estimating the total energy of a flare when the observationally determined parameters are used as the input to a numerical model is discussed. Finally, a critique of the current understanding of flare energetics and the methods used to determine various energetics terms is outlined, and possible future directions of research in this area are suggested.

Process and device for the adsorptive separation of krypton from a krypton/nitrogen gas mixture

International Nuclear Information System (INIS)

Ringel, H.; Messler, M.

1985-01-01

The gas mixture flows through an adsorption column, which is filled with a means of adsorbing Krypton and nitrogen. The adsorption column is desorbed after adsorption of the gas components by a gaseous flushing material, which flows through the adsorption column in the same direction as the gas mixture. In order to achieve a high degree of separation, the adsorption material is loaded with nitrogen and Krypton from the gas inlet, where Krypton is only absorbed over part of the length of the whole column by the adsorption material. The part of the length is such that on desorption of the adsorption column with the flushing material at first only nitrogen and later only Krypton is obtained at the outlet of the adsorption column. (Waste gas system of a reprocession plant). (orig./HP) [de

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

International Nuclear Information System (INIS)

Harmens, H.; Norris, D.A.; Cooper, D.M.; Mills, G.; Steinnes, E.; Kubin, E.; Thoeni, L.; Aboal, J.R.; Alber, R.; Carballeira, A.; Coskun, M.; De Temmerman, L.; Frolova, M.; Gonzalez-Miqueo, L.

2011-01-01

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses ( 2 = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: → Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. → Moss concentrations were compared with EMEP modelled nitrogen deposition. → The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha -1 y -1 . → Linear relationships were found with measured nitrogen deposition in some countries. → Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

Toward a Modular Ionic Liquid Platform for the Custom Design of Energetic Materials: Understanding How the Dual Nature of Ionic Liquids Relates Key Physical Properties to Target Structures

Science.gov (United States)

2009-11-30

Separations to Advanced Materials to Pharmaceuticals: Energetic and API Examples from the Ionic Liquid Cookbook" Presented by R. D. Rogers, before the 2nd...3322 (s), 3219 (s), 3144 (s), 1687 (m), 1571 (s), 1516 (s), 1468 (m), 1435 (m), 1380 (s), 1277 (s), 1205 (s), 1139 (s), 1104 (w), 1043 (w), 1014 (s

Nitrogen solubility in the deep mantle and the origin of Earth's primordial nitrogen budget

Science.gov (United States)

Yoshioka, Takahiro; Wiedenbeck, Michael; Shcheka, Svyatoslav; Keppler, Hans

2018-04-01

The solubility of nitrogen in the major minerals of the Earth's transition zone and lower mantle (wadsleyite, ringwoodite, bridgmanite, and Ca-silicate perovskite) coexisting with a reduced, nitrogen-rich fluid phase was measured. Experiments were carried out in multi-anvil presses at 14 to 24 GPa and 1100 to 1800 °C close to the Fe-FeO buffer. Starting materials were enriched in 15N and the nitrogen concentrations in run products were measured by secondary ion mass spectrometry. Observed nitrogen (15N) solubilities in wadsleyite and ringwoodite typically range from 10 to 250 μg/g and strongly increase with temperature. Nitrogen solubility in bridgmanite is about 20 μg/g, while Ca-silicate perovskite incorporates about 30 μg/g under comparable conditions. Partition coefficients of nitrogen derived from coexisting phases are DNwadsleyite/olivine = 5.1 ± 2.1, DNringwoodite/wadsleyite = 0.49 ± 0.29, and DNbridgmanite/ringwoodite = 0.24 (+ 0.30 / - 0.19). Nitrogen solubility in the solid, iron-rich metal phase coexisting with the silicates was also measured and reached a maximum of nearly 1 wt.% 15N at 23 GPa and 1400 °C. These data yield a partition coefficient of nitrogen between iron metal and bridgmanite of DNmetal/bridgmanite ∼ 98, implying that in a lower mantle containing about 1% of iron metal, about half of the nitrogen still resides in the silicates. The high nitrogen solubility in wadsleyite and ringwoodite may be responsible for the low nitrogen concentrations often observed in ultradeep diamonds from the transition zone. Overall, the solubility data suggest that the transition zone and the lower mantle have the capacity to store at least 33 times the mass of nitrogen presently residing in the atmosphere. By combining the nitrogen solubility data in minerals with data on nitrogen solubility in silicate melts, mineral/melt partition coefficients of nitrogen can be estimated, from which the behavior of nitrogen during magma ocean crystallization can

Construction of control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen

International Nuclear Information System (INIS)

Saminto; Eko Priyono; Sugeng Riyanto

2013-01-01

A control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen have been made. This device consists of the software and hardware component. Hardware component consists of SCR phase angle controller LPC-50HDA type, T100MD1616+ PLC, high voltage transformer and voltage rectifier system. Software component used a LADDER program and TBasic serves to control of the high voltage output. The components in these devices have been tested in the double chamber plasma nitrogen. Its performance meet with the design criteria that can supply of plasma nitrogen operation voltage in the range 290 Vdc to 851 Vdc with glow discharge current 0.4 A to 1.4 A. In general it can be said that the control and instrumentation devices of high voltage power supply is ready for use at the double chamber plasma nitrogen device. (author)

Improved online δ18O measurements of nitrogen- and sulfur-bearing organic materials and a proposed analytical protocol

Science.gov (United States)

Qi, H.; Coplen, T.B.; Wassenaar, L.I.

2011-01-01

It is well known that N2 in the ion source of a mass spectrometer interferes with the CO background during the δ18O measurement of carbon monoxide. A similar problem arises with the high-temperature conversion (HTC) analysis of nitrogenous O-bearing samples (e.g. nitrates and keratins) to CO for δ18O measurement, where the sample introduces a significant N2 peak before the CO peak, making determination of accurate oxygen isotope ratios difficult. Although using a gas chromatography (GC) column longer than that commonly provided by manufacturers (0.6 m) can improve the efficiency of separation of CO and N2 and using a valve to divert nitrogen and prevent it from entering the ion source of a mass spectrometer improved measurement results, biased δ18O values could still be obtained. A careful evaluation of the performance of the GC separation column was carried out. With optimal GC columns, the δ18O reproducibility of human hair keratins and other keratin materials was better than ±0.15 ‰ (n = 5; for the internal analytical reproducibility), and better than ±0.10 ‰ (n = 4; for the external analytical reproducibility).

Deep energetic trap states in organic photovoltaic devices

KAUST Repository

Shuttle, Christopher G.; Treat, Neil D.; Douglas, Jessica D.; Frechet, Jean; Chabinyc, Michael L.

2011-01-01

The nature of energetic disorder in organic semiconductors is poorly understood. In photovoltaics, energetic disorder leads to reductions in the open circuit voltage and contributes to other loss processes. In this work, three independent optoelectronic methods were used to determine the long-lived carrier populations in a high efficiency N-alkylthieno[3,4-c]pyrrole-4,6-dione (TPD) based polymer: fullerene solar cell. In the TPD co-polymer, all methods indicate the presence of a long-lived carrier population of ∼ 10 15 cm -3 on timescales ≤100 μs. Additionally, the behavior of these photovoltaic devices under optical bias is consistent with deep energetic lying trap states. Comparative measurements were also performed on high efficiency poly-3-hexylthiophene (P3HT): fullerene solar cells; however a similar long-lived carrier population was not observed. This observation is consistent with a higher acceptor concentration (doping) in P3HT than in the TPD-based copolymer. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deep energetic trap states in organic photovoltaic devices

KAUST Repository

Shuttle, Christopher G.

2011-11-23

The nature of energetic disorder in organic semiconductors is poorly understood. In photovoltaics, energetic disorder leads to reductions in the open circuit voltage and contributes to other loss processes. In this work, three independent optoelectronic methods were used to determine the long-lived carrier populations in a high efficiency N-alkylthieno[3,4-c]pyrrole-4,6-dione (TPD) based polymer: fullerene solar cell. In the TPD co-polymer, all methods indicate the presence of a long-lived carrier population of ∼ 10 15 cm -3 on timescales ≤100 μs. Additionally, the behavior of these photovoltaic devices under optical bias is consistent with deep energetic lying trap states. Comparative measurements were also performed on high efficiency poly-3-hexylthiophene (P3HT): fullerene solar cells; however a similar long-lived carrier population was not observed. This observation is consistent with a higher acceptor concentration (doping) in P3HT than in the TPD-based copolymer. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-Dimensional Porous Nitrogen-Doped NiO Nanostructures as Highly Sensitive NO2 Sensors

Directory of Open Access Journals (Sweden)

Van Hoang Luan

2017-10-01

Full Text Available Nickel oxide has been widely used in chemical sensing applications, because it has an excellent p-type semiconducting property with high chemical stability. Here, we present a novel technique of fabricating three-dimensional porous nitrogen-doped nickel oxide nanosheets as a highly sensitive NO2 sensor. The elaborate nanostructure was prepared by a simple and effective hydrothermal synthesis method. Subsequently, nitrogen doping was achieved by thermal treatment with ammonia gas. When the p-type dopant, i.e., nitrogen atoms, was introduced in the three-dimensional nanostructures, the nickel-oxide-nanosheet-based sensor showed considerable NO2 sensing ability with two-fold higher responsivity and sensitivity compared to non-doped nickel-oxide-based sensors.

High-throughput quantum chemistry and virtual screening for OLED material components

Science.gov (United States)

Halls, Mathew D.; Giesen, David J.; Hughes, Thomas F.; Goldberg, Alexander; Cao, Yixiang

2013-09-01

Computational structure enumeration, analysis using an automated simulation workflow and filtering of large chemical structure libraries to identify lead systems, has become a central paradigm in drug discovery research. Transferring this paradigm to challenges in materials science is now possible due to advances in the speed of computational resources and the efficiency and stability of chemical simulation packages. State-of-the-art software tools that have been developed for drug discovery can be applied to efficiently explore the chemical design space to identify solutions for problems such as organic light-emitting diode material components. In this work, virtual screening for OLED materials based on intrinsic quantum mechanical properties is illustrated. Also, a new approach to more reliably identify candidate systems is introduced that is based on the chemical reaction energetics of defect pathways for OLED materials.

Material Usage in High Pressure Oxygen Systems for the International Space Station

Science.gov (United States)

Kravchenko, Michael; Sievers, D. Elliott

2014-01-01

The Nitrogen/Oxygen Recharge System (NORS) for the International Space Station (ISS) Program was required as part of the Space Shuttle retirement efforts to sustain the ISS life support systems. The system is designed around a 7000 psia Oxygen or Nitrogen Recharge Tank Assembly which is able to be utilized both internally and externally to the ISS. Material selection and usage were critical to ensure oxygen compatibility for the design, while taking into consideration toxicity, weldability, brazability and general fabrication and assembly techniques. The system uses unique hardware items such a composite overwrap pressure vessel (COPV), high pressure mechanical gauges, compact regulators and valves, quick disconnects, metal tubing and flexhoses. Numerous challenges and anomalies were encountered due to the exotic nature of this project which will be discussed in detail. The knowledge gained from these anomalies and failure resolutions can be applied to more than space applications, but can also be applicable to industry pressurized systems.

A Nanopore-Structured Nitrogen-Doped Biocarbon Electrocatalyst for Oxygen Reduction from Two-Step Carbonization of Lemna minor Biomass