Biomineral repair of abalone shell apertures.

Science.gov (United States)

Cusack, Maggie; Guo, Dujiao; Chung, Peter; Kamenos, Nicholas A

2013-08-01

The shell of the gastropod mollusc, abalone, is comprised of nacre with an outer prismatic layer that is composed of either calcite or aragonite or both, depending on the species. A striking characteristic of the abalone shell is the row of apertures along the dorsal margin. As the organism and shell grow, new apertures are formed and the preceding ones are filled in. Detailed investigations, using electron backscatter diffraction, of the infill in three species of abalone: Haliotis asinina, Haliotis gigantea and Haliotis rufescens reveals that, like the shell, the infill is composed mainly of nacre with an outer prismatic layer. The infill prismatic layer has identical mineralogy as the original shell prismatic layer. In H. asinina and H. gigantea, the prismatic layer of the shell and infill are made of aragonite while in H. rufescens both are composed of calcite. Abalone builds the infill material with the same high level of biological control, replicating the structure, mineralogy and crystallographic orientation as for the shell. The infill of abalone apertures presents us with insight into what is, effectively, shell repair. Copyright © 2013 Elsevier Inc. All rights reserved.

Performance of the LHCb Outer Tracker

CERN Document Server

Arink, R; Bachmann, S.; Bagaturia, Y.; Band, H.; Bauer, Th.; Berkien, A.; Farber, Ch.; Bien, A.; Blouw, J.; Ceelie, L.; Coco, V.; Deckenhoff, M.; Deng, Z.; Dettori, F.; van Eijk, D.; Ekelhof, R.; Gersabeck, E.; Grillo, L.; Hulsbergen, W.D.; Karbach, T.M.; Koopman, R.; Kozlinskiy, A.; Langenbruch, Ch.; Lavrentyev, V.; Linn, Ch.; Merk, M.; Merkel, J.; Meissner, M.; Michalowski, J.; Morawski, P.; Nawrot, A.; Nedos, M.; Pellegrino, A.; Polok, G.; van Petten, O.; Rovekamp, J.; Schimmel, F.; Schuylenburg, H.; Schwemmer, R.; Seyfert, P.; Serra, N.; Sluijk, T.; Spaan, B.; Spelt, J.; Storaci, B.; Szczekowski, M.; Swientek, S.; Tolk, S.; Tuning, N.; Uwer, U.; Wiedner, D.; Witek, M.; Zeng, M.; Zwart, A.

2014-01-01

The LHCb Outer Tracker is a gaseous detector covering an area of 5x6 m2 with 12 double layers of straw tubes. The detector with its services are described together with the commissioning and calibration procedures. Based on data of the first LHC running period from 2010 to 2012, the performance of the readout electronics and the single hit resolution and efficiency are presented. The efficiency to detect a hit in the central half of the straw is estimated to be 99.2%, and the position resolution is determined to be approximately 200 um. The Outer Tracker received a dose in the hottest region corresponding to 0.12 C/cm, and no signs of gain deterioration or other ageing effects are observed.

Preparation of yolk-shell MoS2 nanospheres covered with carbon shell for excellent lithium-ion battery anodes

Science.gov (United States)

Guo, Bangjun; Feng, Yu; Chen, Xiaofan; Li, Bo; Yu, Ke

2018-03-01

Molybdenum disulfide is regarded as one of the most promising electrode materials for high performance lithium-ion batteries. Designing firm basal structure is a key point to fully utilize the high capacity of layered MoS2 nanomaterials. Here, yolk-shell structured MoS2 nanospheres is firstly designed and fabricated to meet this needs. This unique yolk-shell nanospheres are transformed from solid nanospheres by a simply weak alkaline etching method. Then, the yolk-shell MoS2/C is synthesized by a facile process to protect the outside MoS2 shell and promote the conductivity. Taking advantages of high capacity and well-defined cavity space, allowing the core MoS2 to expand freely without breaking the outer shells, yolk-shell MoS2/C nanospheres delivers long cycle life (94% of capacity retained after 200 cycles) and high rate behaviour (830 mA h g-1 at 5 A g-1). This design of yolk-shell structure may set up a new strategy for preparing next generation anode materials for LIBs.

Performance requirements for the single-shell tank

International Nuclear Information System (INIS)

GRENARD, C.E.

1999-01-01

This document provides performance requirements for the waste storage and waste feed delivery functions of the Single-Shell Tank (SST) System. The requirements presented here in will be used as a basis for evaluating the ability of the system to complete the single-shell tank waste feed delivery mission. They will also be used to select the technology or technologies for retrieving waste from the tanks selected for the single-shell tank waste feed delivery mission, assumed to be 241-C-102 and 241-C-104. This revision of the Performance Requirements for the SST is based on the findings of the SST Functional Analysis, and are reflected in the current System Specification for the SST System

Structural determinants of the outer shell of β-carboxysomes in Synechococcus elongatus PCC 7942: roles for CcmK2, K3-K4, CcmO, and CcmL.

Directory of Open Access Journals (Sweden)

Benjamin D Rae

Full Text Available Cyanobacterial CO(2-fixation is supported by a CO(2-concentrating mechanism which improves photosynthesis by saturating the primary carboxylating enzyme, ribulose 1, 5-bisphosphate carboxylase/oxygenase (RuBisCO, with its preferred substrate CO(2. The site of CO(2-concentration is a protein bound micro-compartment called the carboxysome which contains most, if not all, of the cellular RuBisCO. The shell of β-type carboxysomes is thought to be composed of two functional layers, with the inner layer involved in RuBisCO scaffolding and bicarbonate dehydration, and the outer layer in selective permeability to dissolved solutes. Here, four genes (ccmK2-4, ccmO, whose products were predicted to function in the outer shell layer of β-carboxysomes from Synechococcus elongatus PCC 7942, were investigated by analysis of defined genetic mutants. Deletion of the ccmK2 and ccmO genes resulted in severe high-CO(2-requiring mutants with aberrant carboxysomes, whilst deletion of ccmK3 or ccmK4 resulted in cells with wild-type physiology and normal ultrastructure. However, a tandem deletion of ccmK3-4 resulted in cells with wild-type carboxysome structure, but physiologically deficient at low CO(2 conditions. These results revealed the minimum structural determinants of the outer shell of β-carboxysomes from this strain: CcmK2, CcmO and CcmL. An accessory set of proteins was required to refine the function of the pre-existing shell: CcmK3 and CcmK4. These data suggested a model for the facet structure of β-carboxysomes with CcmL forming the vertices, CcmK2 forming the bulk facet, and CcmO, a "zipper protein," interfacing the edges of carboxysome facets.

Nanostructued core–shell Sn nanowires @ CNTs with controllable thickness of CNT shells for lithium ion battery

Energy Technology Data Exchange (ETDEWEB)

Zhong, Yu; Li, Xifei; Zhang, Yong; Li, Ruying [Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada); Cai, Mei [General Motors Research and Development Center, Warren, MI 48090-9055 (United States); Sun, Xueliang, E-mail: xsun@eng.uwo.ca [Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada)

2015-03-30

Graphical abstract: - Highlights: • Sn nanowires encapsulated in CNTs directly grew on current collectors. • The thickness of CNTs were controlled via growth time, gas flow rate and synthesis temperature. • Thick CNTs contributed to a better capacity retention while thin CNTs led to a higher capacity. • The core–shell structures formed in one-step CVD process. - Abstract: Core–shell structure of Sn nanowires encapsulated in amorphous carbon nanotubes (Sn@CNTs) with controlled thickness of CNT shells was in situ prepared via chemical vapor deposition (CVD) method. The thickness of CNT shells was accurately controlled from 4 to 99 nm by using different growth time, flow rate of hydrocarbon gas (C{sub 2}H{sub 4}) and synthesis temperature. The microstructure and composition of the coaxial Sn@CNTs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM) techniques. Moreover, the Sn@CNTs were studied as anode materials for Li-ion batteries and showed excellent cycle performance. The capacity was affected by the thickness of outer CNT shells: thick CNT shells contributed to a better retention while thin CNT shells led to a higher capacity. The thin CNT shell of 6 nm presented the highest capacity around 630 mAh g{sup −1}.

Nanostructued core–shell Sn nanowires @ CNTs with controllable thickness of CNT shells for lithium ion battery

International Nuclear Information System (INIS)

Zhong, Yu; Li, Xifei; Zhang, Yong; Li, Ruying; Cai, Mei; Sun, Xueliang

2015-01-01

Graphical abstract: - Highlights: • Sn nanowires encapsulated in CNTs directly grew on current collectors. • The thickness of CNTs were controlled via growth time, gas flow rate and synthesis temperature. • Thick CNTs contributed to a better capacity retention while thin CNTs led to a higher capacity. • The core–shell structures formed in one-step CVD process. - Abstract: Core–shell structure of Sn nanowires encapsulated in amorphous carbon nanotubes (Sn@CNTs) with controlled thickness of CNT shells was in situ prepared via chemical vapor deposition (CVD) method. The thickness of CNT shells was accurately controlled from 4 to 99 nm by using different growth time, flow rate of hydrocarbon gas (C 2 H 4 ) and synthesis temperature. The microstructure and composition of the coaxial Sn@CNTs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM) techniques. Moreover, the Sn@CNTs were studied as anode materials for Li-ion batteries and showed excellent cycle performance. The capacity was affected by the thickness of outer CNT shells: thick CNT shells contributed to a better retention while thin CNT shells led to a higher capacity. The thin CNT shell of 6 nm presented the highest capacity around 630 mAh g −1

Minimizing shell-and-tube heat exchanger cost with genetic algorithms and considering maintenance

Energy Technology Data Exchange (ETDEWEB)

Wildi-Tremblay, P.; Gosselin, L. [Universite Laval, Quebec (Canada). Dept. de genie mecanique

2007-07-15

This paper presents a procedure for minimizing the cost of a shell-and-tube heat exchanger based on genetic algorithms (GA). The global cost includes the operating cost (pumping power) and the initial cost expressed in terms of annuities. Eleven design variables associated with shell-and-tube heat exchanger geometries are considered: tube pitch, tube layout patterns, number of tube passes, baffle spacing at the centre, baffle spacing at the inlet and outlet, baffle cut, tube-to-baffle diametrical clearance, shell-to-baffle diametrical clearance, tube bundle outer diameter, shell diameter, and tube outer diameter. Evaluations of the heat exchangers performances are based on an adapted version of the Bell-Delaware method. Pressure drops constraints are included in the procedure. Reliability and maintenance due to fouling are taken into account by restraining the coefficient of increase of surface into a given interval. Two case studies are presented. Results show that the procedure can properly and rapidly identify the optimal design for a specified heat transfer process. (author)

The dorsal shell wall structure of Mesozoic ammonoids

Directory of Open Access Journals (Sweden)

Gregor Radtke

2017-03-01

Full Text Available The study of pristine preserved shells of Mesozoic Ammonoidea shows different types of construction and formation of the dorsal shell wall. We observe three major types: (i The vast majority of Ammonoidea, usually planispirally coiled, has a prismatic reduced dorsal shell wall which consists of an outer organic component (e.g., wrinkle layer, which is the first layer to be formed, and the subsequently formed dorsal inner prismatic layer. The dorsal mantle tissue suppresses the formation of the outer prismatic layer and nacreous layer. With the exception of the outer organic component, secretion of a shell wall is omitted at the aperture. A prismatic reduced dorsal shell wall is always secreted immediately after the hatching during early teleoconch formation. Due to its broad distribution in (planispiral Ammonoidea, the prismatic reduced dorsal shell wall is probably the general state. (ii Some planispirally coiled Ammonoidea have a nacreous reduced dorsal shell wall which consists of three mineralized layers: two prismatic layers (primary and secondary dorsal inner prismatic layer and an enclosed nacreous layer (secondary dorsal nacreous layer. The dorsal shell wall is omitted at the aperture and was secreted in the rear living chamber. Its layers are a continuation of an umbilical shell doubling (reinforcement by additional shell layers that extends towards the ventral crest of the preceding whorl. The nacreous reduced dorsal shell wall is formed in the process of ontogeny following a prismatic reduced dorsal shell wall. (iii Heteromorph and some planispirally coiled taxa secrete a complete dorsal shell wall which forms a continuation of the ventral and lateral shell layers. It is formed during ontogeny following a prismatic reduced dorsal shell wall or a priori. The construction is identical with the ventral and lateral shell wall, including a dorsal nacreous layer. The wide distribution of the ability to form dorsal nacre indicates that it is

Core-shell nanoparticles optical sensors - Rational design of zinc ions fluorescent nanoprobes of improved analytical performance

Science.gov (United States)

Woźnica, Emilia; Gasik, Joanna; Kłucińska, Katarzyna; Kisiel, Anna; Maksymiuk, Krzysztof; Michalska, Agata

2017-10-01

In this work the effect of affinity of an analyte to a receptor on the response of nanostructural fluorimetric probes is discussed. Core-shell nanoparticles sensors are prepared that benefit from the properties of the phases involved leading to improved analytical performance. The optical transduction system chosen is independent of pH, thus the change of sample pH can be used to control the analyte - receptor affinity through the "conditional" binding constant prevailing within the lipophilic phase. It is shown that by affecting the "conditional" binding constant the performance of the sensor can be fine-tuned. As expected, increase in "conditional" affinity of the ligand embedded in the lipophilic phase to the analyte results in higher sensitivity over narrow concentration range - bulk reaction and sigmoidal shape response of emission intensity vs. logarithm of concentration changes. To induce a linear dependence of emission intensity vs. logarithm of analyte concentration covering a broad concentration range, a spatial confinement of the reaction zone is proposed, and application of core-shell nanostructures. The core material, polypyrrole nanospheres, is effectively not permeable for the analyte - ligand complex, thus the reaction is limited to the outer shell layer of the polymer prepared from poly(maleic anhydride-alt-1-octadecene). For herein introduced system a linear dependence of emission intensity vs. logarithm of Zn2+ concentration was obtained within the range from 10-7 to 10-1 M.

Sinusoidal velaroidal shell – numerical modelling of the nonlinear ...

African Journals Online (AJOL)

The nonlinearity, applied to a sinusoidal velaroidal shell with the inner radius r0, the outer variables radii from 10m to 20m and the number of waves n=8, will give rise to the investigation of its nonlinear buckling resistance. The building material is a high-performant concrete. The investigation emphasizes more on the ...

A Core-Shell Fe/Fe2 O3 Nanowire as a High-Performance Anode Material for Lithium-Ion Batteries.

Science.gov (United States)

Na, Zhaolin; Huang, Gang; Liang, Fei; Yin, Dongming; Wang, Limin

2016-08-16

The preparation of novel one-dimensional core-shell Fe/Fe2 O3 nanowires as anodes for high-performance lithium-ion batteries (LIBs) is reported. The nanowires are prepared in a facile synthetic process in aqueous solution under ambient conditions with subsequent annealing treatment that could tune the capacity for lithium storage. When this hybrid is used as an anode material for LIBs, the outer Fe2 O3 shell can act as an electrochemically active material to store and release lithium ions, whereas the highly conductive and inactive Fe core functions as nothing more than an efficient electrical conducting pathway and a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium ions. The core-shell Fe/Fe2 O3 nanowire maintains an excellent reversible capacity of over 767 mA h g(-1) at 500 mA g(-1) after 200 cycles with a high average Coulombic efficiency of 98.6 %. Even at 2000 mA g(-1) , a stable capacity as high as 538 mA h g(-1) could be obtained. The unique composition and nanostructure of this electrode material contribute to this enhanced electrochemical performance. Due to the ease of large-scale fabrication and superior electrochemical performance, these hybrid nanowires are promising anode materials for the next generation of high-performance LIBs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controllable dielectric and electrical performance of polymer composites with novel core/shell-structured conductive particles through biomimetic method

International Nuclear Information System (INIS)

Yang, Dan; Tian, Ming; Wang, Wencai; Li, Dongdong; Li, Runyuan; Liu, Haoliang; Zhang, Liqun

2013-01-01

Highlights: ► Conductive core/shell-structured particles were synthesized by biomimetic method. ► These particles with silica/poly(dopamine)/silver core and poly(dopamine) shell. ► Dielectric composites were prepared with resulted particles and silicone elastomer. ► The dielectric properties of the composites can be controlled by shell thickness. ► This biomimetic method is simple, nontoxic, efficient and easy to control. - Abstract: Novel silica/poly(dopamine)/silver (from inner to outer) (denoted as SiO 2 /PDA/Ag) conductive micro-particles were first synthesized by biomimetic poly(dopamine) coating. These micro-particles were then coated with a poly(dopamine) layer to form core/shell-structured particles, with silica/poly(dopamine)/silver core and poly(dopamine) shell (denoted as SiO 2 /PDA/Ag/PDA). This multilayer core/shell micro-particles were confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscope. Polymer composites were then prepared by mechanical blending of poly(dimethyl siloxane) and the core/shell-structured particles. It was found that the silver layer and the poly(dopamine) shell had good adhesion with substrate and they kept intact even under violent shearing stress during mechanical mixing. The effect of the thickness of outermost poly(dopamine) shell as well as the loading amount of this filler on the dielectric and electrical properties of the composites was further studied. The results showed that the dielectric constant, dielectric loss, and conductivity of the composites decreased with increasing shell thickness (10–53 nm) at the same loading level. And the maximal dielectric constant of composites was achieved in the composites filled with SiO 2 /PDA/Ag/PDA (with 10–15 nm PDA shell) particles, which was much larger than that of the composite filled with SiO 2 /PDA/Ag particles without insulative PDA shell. At the same time, the composites can change

Adsorptive Removal of Methylene Blue onto ZnCl2 Activated Carbon from Wood Apple Outer Shell: Kinetics and Equilibrium Studies

Directory of Open Access Journals (Sweden)

N. Bhadusha

2011-01-01

Full Text Available Methylene blue dye removal from aqueous solution was investigated using ZnCl2 activated carbon prepared from wood apple outer shell (Limonia acidissima, biomass waste. Influence of agitation time, adsorbent dose, dye concentration, pH and temperature were explored. Two theoretical adsorption isotherms namely Langmuir and Freundlich were used to describe the experimental results. The Langmuir adsorption capacity (Qo was found to be 35.1 mg/g and the equilibrium parameter (RL values indicate favourable adsorption. The experimental data were well fitted with Langmuir isotherm model and pseudo second order kinetic model. Desorption studies showed that ion exchange mechanism might be involved in the adsorption process.

Multi-shelled ZnCo2O4 yolk-shell spheres for high-performance acetone gas sensor

Science.gov (United States)

Xiong, Ya; Zhu, Zongye; Ding, Degong; Lu, Wenbo; Xue, Qingzhong

2018-06-01

In the present study, multi-shelled ZnCo2O4 yolk-shell spheres have been successfully prepared by using carbonaceous microspheres as templates. It is found that the multi-shelled ZnCo2O4 yolk-shell spheres based sensor shows optimal sensing performances (response value of 38.2, response/recovery time of 19 s/71 s) toward 500 ppm acetone at 200 °C. In addition, this sensor exhibits a low detection limit of 0.5 ppm acetone (response value of 1.36) and a good selectivity toward hydrogen, methane, ethanol, ammonia and carbon dioxide. Furthermore, it is demonstrated that acetone gas response of multi-shelled ZnCo2O4 yolk-shell spheres is significantly better than that of ZnCo2O4 nanotubes and ZnCo2O4 nanosheets. High acetone response of the multi-shelled ZnCo2O4 yolk-shell spheres is attributed to the enhanced gas accessibility of the multi-shell morphology caused by the small crystalline size and high specific surface area while the short response/recovery time is mainly related to the rapid gas diffusion determined by the highly porous structure. Our work puts forward an exciting opportunity in designing various yolk-shelled structures for multipurpose applications.

Photoionization of the outer electrons in noble gas endohedral atoms

International Nuclear Information System (INIS)

Amusia, M. Ya.; Baltenkov, A. S.; Chernysheva, L. V.

2008-01-01

We suggest a prominent modification of the outer shell photoionization cross section in noble gas (NG) endohedral atoms NG-C n under the action of the electron shell of fullerene C n . This shell leads to two important effects: a strong enhancement of the cross section due to fullerene shell polarization under the action of the incoming electromagnetic wave and to prominent oscillation of this cross section due to the reflection of a photoelectron from the NG by the fullerene shell. Both factors lead to powerful maxima in the outer shell ionization cross sections of NG-C n , which we call giant endohedral resonances. The oscillator strength reaches a very large value in the atomic scale, 25. We consider atoms of all noble gases except He. The polarization of the fullerene shell is expressed in terms of the total photoabsorption cross section of the fullerene. The photoelectron reflection is taken into account in the framework of the so-called bubble potential, which is a spherical δ-type potential. It is assumed in the derivations that the NG is centrally located in the fullerene. It is also assumed, in accordance with the existing experimental data, that the fullerene radius R C is much larger than the atomic radius r A and the thickness Δ C of the fullerene shell. As was demonstrated recently, these assumptions allow us to represent the NG-C n photoionization cross section as a product of the NG cross section and two well-defined calculated factors

Low power multiple shell fusion targets for use with electron and ion beams

International Nuclear Information System (INIS)

Lindl, J.D.; Bangerter, R.O.

1975-01-01

Use of double shell targets with a separate low Z, low density ablator at large radius for the outer shell, reduces the focusing and power requirements while maintaining reasonable aspect ratios. A high Z, high density pusher shell is placed at a much smaller radius in order to obtain an aspect ratio small enough to protect against fluid instability. Velocity multiplication between these shells further lowers the power requirements. Careful tuning of the power profile and intershell density results in a low entropy implosion which allows breakeven at low powers. Ion beams appear to be a promising power source and breakeven at 10-20 Terrawatts with 10 MeV alpha particles appears feasible. Predicted performance of targets with various energy sources is shown and comparison is made with single shell targets

Non-dipole angular anisotropy parameters of photoelectrons from semi-filled shell atoms

Energy Technology Data Exchange (ETDEWEB)

Amusia, M Ya [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Chernysheva, L V [Ioffe Physical-Technical Institute, St-Petersburg 194021 (Russian Federation)

2006-11-28

We present the results of calculations of outer and next to outer shell non-dipole angular anisotropy parameters of photoelectrons for semi-filled shell atoms in the Hartree-Fock (HF) one-electron approximation and in the frame of the spin polarized random phase approximation with exchange (SP RPAE) which takes into account inter-electron correlations. We demonstrate for the first time that this characteristic of the photoionization process is essentially sensitive to whether the photoelectron has the same or opposite spin orientation to that of the semi-filled shell.

Non-dipole angular anisotropy parameters of photoelectrons from semi-filled shell atoms

International Nuclear Information System (INIS)

Amusia, M Ya; Chernysheva, L V

2006-01-01

We present the results of calculations of outer and next to outer shell non-dipole angular anisotropy parameters of photoelectrons for semi-filled shell atoms in the Hartree-Fock (HF) one-electron approximation and in the frame of the spin polarized random phase approximation with exchange (SP RPAE) which takes into account inter-electron correlations. We demonstrate for the first time that this characteristic of the photoionization process is essentially sensitive to whether the photoelectron has the same or opposite spin orientation to that of the semi-filled shell

A novel core–shell nanocomposite Ni–Ca@mSiO_2 for benzophenone selective hydrogenation

International Nuclear Information System (INIS)

Han, Xue; Feng, Wenhui; Chu, Xiaoning; Chu, Hailong; Niu, Libo; Bai, Guoyi

2017-01-01

A novel core–shell nanocomposite Ni–Ca@mSiO_2 was first prepared by a modified Stöber method in this paper. It has a core–shell structure with Ni (about 8 nm in diameter) and Ca as the cores and mesoporous silica as the outer shell, as proven by the transmission electron microscopy. This nanocomposite exhibited good catalytic performance in the selective hydrogenation of benzophenone, with 96.1% conversion and 94.9% selectivity for benzhydrol under relatively mild reaction conditions. It was demonstrated that addition of small amounts of alkaline Ca can not only markedly improve the dispersion of the active species but also tune the acid–base property of this nanocomposite, resulting in the efficient suppression of benzhydrol dehydration to achieve a high selectivity. Furthermore, the core–shell nanocomposite Ni–Ca@mSiO_2 can be recycled four runs without appreciable loss of its initial activity, more stable than the traditional supported nanocatalyst Ni–Ca/mSiO_2. It was suggested that the outer mesoporous silica shell of Ni–Ca@mSiO_2 can prevent both the aggregation and the leaching of the active Ni species, accounting for its relatively good stability.

Detailed Performance of the Outer Tracker at LHCb

CERN Document Server

Tuning, N

2014-01-01

The LHCb Outer Tracker is a gaseous detector covering an area of 5x6m2 with 12 double layers of straw tubes. Based on data of the first LHC running period from 2010 to 2012, the performance in terms of the single hit resolution and efficiency are presented. Details on the ionization length and subtle effects regarding signal reflections and the subsequent time-walk correction are given. The efficiency to detect a hit in the central half of the straw is estimated to be 99.2%, and the position resolution is determined to be approximately 200 um, depending on the detailed implementation of the internal alignment of individual detector modules. The Outer Tracker received a dose in the hottest region corresponding to 0.12 C/cm, and no signs of gain deterioration or other ageing effects are observed.

Collisional alignment and orientation of atomic outer shells. Pt. 1

International Nuclear Information System (INIS)

Andersen, N.; Gallagher, J.W.; Hertel, I.V.

1988-01-01

The study of polarization of atomic radiation emitted after impact excitation has yielded an enormous wealth of detailed information on the mechanism and dynamics of collisional excitation and energy transfer, both in electron and heavy particle impact studies. In these studies, the beam of electrons, ions or fast atoms used to excite the target atoms provides a suitable quantization axis with respect to which the polarization of the fluorescent light of the excited atoms is detected. From these data information on the cross sections for the different magnetic substates of the excited atom is extracted, imparting a great deal of insight into impact mechanisms for both outer and inner shell excitation. It is our aim to provide a comprehensive review including all data available in the literature presented in a standardized and easily accessible fashion. In this review we include only alignment and orientation studies, which have a well-defined planar symmetry, i.e., in which the initial and final relative momentum of the interacting particles are well defined by differential scattering techniques. We do not make a major distinction between heavy-particle and electron impact excitation: In fact, one of our aims is to demonstrate similarities between the two fields from a technical as well as from a conceptual point of view. The review is divided into three parts: This first part (I) deals with direct excitation of atoms by electrons and fast atoms or ions. Section 2 gives an introduction to the general concepts and ideas behind this kind of study and a description of typical experimental setups. Section 3 deals with electron impact excitation of atoms, starting with the simplest case of electron-helium collisions which may be fully described by two parameters, followed by more complex cases such as electron impact excitation of hydrogen and the heavy rare gases. Section 4 describes the results for direct excitation by atomic impact. (orig./AH)

A novel core–shell nanocomposite Ni–Ca@mSiO{sub 2} for benzophenone selective hydrogenation

Energy Technology Data Exchange (ETDEWEB)

Han, Xue; Feng, Wenhui; Chu, Xiaoning; Chu, Hailong; Niu, Libo; Bai, Guoyi, E-mail: baiguoyi@hotmail.com [Hebei University, Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science (China)

2017-02-15

A novel core–shell nanocomposite Ni–Ca@mSiO{sub 2} was first prepared by a modified Stöber method in this paper. It has a core–shell structure with Ni (about 8 nm in diameter) and Ca as the cores and mesoporous silica as the outer shell, as proven by the transmission electron microscopy. This nanocomposite exhibited good catalytic performance in the selective hydrogenation of benzophenone, with 96.1% conversion and 94.9% selectivity for benzhydrol under relatively mild reaction conditions. It was demonstrated that addition of small amounts of alkaline Ca can not only markedly improve the dispersion of the active species but also tune the acid–base property of this nanocomposite, resulting in the efficient suppression of benzhydrol dehydration to achieve a high selectivity. Furthermore, the core–shell nanocomposite Ni–Ca@mSiO{sub 2} can be recycled four runs without appreciable loss of its initial activity, more stable than the traditional supported nanocatalyst Ni–Ca/mSiO{sub 2}. It was suggested that the outer mesoporous silica shell of Ni–Ca@mSiO{sub 2} can prevent both the aggregation and the leaching of the active Ni species, accounting for its relatively good stability.

Double containment shell for nuclear power plants

International Nuclear Information System (INIS)

Sykora, D.

1977-01-01

A double containment shell is proposed for nuclear power plants, especially those equipped with pressurized water reactors. The shell offers increased environmental protection from primary circuit accidents. The inner shell is built of steel or concrete while the outer shell is always built of concrete. The space between the two shells is filled with water and is provided with several manholes and with stiffeners designed for compensation for load due to the water hydrostatic pressure. Water serves the airtight separation of the containment shell inside from the environment and the absorption of heat released in a primary circuit accident. In case the inner shell is made of concrete, it is provided with heat-removal tubes in-built in its walls ensuring rapid heat transfer from the inside of the containment to the water in the interwall space. (Z.M.)

In-depth nanocrystallization enhanced Li-ions batteries performance with nitrogen-doped carbon coated Fe3O4 yolk-shell nanocapsules

Science.gov (United States)

Wu, Qianhui; Zhao, Rongfang; Liu, Wenjie; Zhang, Xiue; Shen, Xiao; Li, Wenlong; Diao, Guowang; Chen, Ming

2017-03-01

In this paper nitrogen-doped carbon-encapsulation Fe3O4 yolk-shell magnetic nanocapsules (Fe3O4@C-N nanocapsules) have been successfully constructed though a facile hydrothermal method and subsequent annealing process. Fe3O4 nanoparticles are completely enclosed in nitrogen-doped carbon shells with void space between the nanoparticle and the shell. The yolk-shell structure allows Fe3O4 nanoparticles to expand freely without breaking the outer carbon shell during the lithiation/delithiation processes. The volume expansion of Fe3O4 results in the in-depth nanocrystallization. Fortunately, the new generated small nanoparticles can increase the capability with the cycle increase due to the unique confinement effect and excellent electronic conductivity of the nitrogen-doped carbon shells. Hence, after 150 cycles, the discharge capacity of Fe3O4@C-N-700 nanocapsules still remained 832 mA h g-1 at 500 mA g-1, which corresponds to 116.7% of the lowest capacity (713 mA h g-1) at the 16th cycle. We believe that the yolk-shell structure is conducive to enhance the capacity of easy pulverization metal oxidation during the charge/discharge processes.

Performance requirements for the double-shell tank system: Phase 1

International Nuclear Information System (INIS)

Claghorn, R.D.

1998-01-01

This document establishes performance requirements for the double-shell tank system. These requirements, in turn, will be incorporated in the System Specification for the Double-Shell Tank System (Grenard and Claghorn 1998). This version of the document establishes requirements that are applicable to the first phase (Phase 1) of the Tank Waste Remediation System (TWRS) mission described in the TWRS Mission Analysis Report (Acree 1998). It does not specify requirements for either the Phase 2 mission or the double-shell tank system closure period

Analysis of radial vibrations of poroelastic circular cylindrical shells ...

African Journals Online (AJOL)

DR OKE

vanished, the considered problem reduces to the problem of radial vibrations of fluid-filled poroelastic circular cylindrical shell. (2). When the .... the volume change of the solid to that of liquid. ..... When the outer fluid density is zero, that is, ρof = 0 then the poroelastic cylindrical shell immersed in an acoustic medium will.

Geochemical gradients within modern and fossil shells of Concholepas concholepas from northern Chile: an insight into U-Th systematics and diagenetic/authigenic isotopic imprints in mollusk shells

Science.gov (United States)

Labonne, Maylis; Hillaire-Marcel, Claude

2000-05-01

Seriate geochemical measurements through shells of one modern, one Holocene, and two Sangamonian Concholepas concholepas, from marine terraces of Northern Chile, were performed to document diagenetic vs. authigenic geochemical signatures, and to better interpret U-series ages on such material. Subsamples were recovered by drilling from the outer calcitic layer to the inner aragonitic layer of each of the studied shells. Unfortunately, this sampling procedure induces artifacts, notably the convertion of up to ˜20% of calcite into aragonite, and of up to ˜6% of aragonite into calcite, as well as in the epimerization of a few percent of isoleucine into D-alloisoleucine/ L-isoleucine. Negligible sampling artifacts were noticed for stable isotope and total amino acid contents. Diagenetic effects on the geochemical properties of the shells are particularly pronounced in the inner aragonitic layer and more discrete in the outer calcitic layer. The time-dependent decay of the organic matrix of the shell is illustrated by a one order of magnitude lower total amino acid content in the Sangamonian specimens by comparison with the modern shell. Conversely, the Sangamonian shells U contents increase by a similar factor and 13C- 18O enrichments as high as 2 to 3‰ seem also to occur through the same time interval possibly due to partial replacement of aragonite by gypsum. The decay of the organic matrix of the aragonitic layer of the shell is thought to play a major role with respect to U-uptake processes and stable isotope shifts. Nevertheless, asymptotic 230Th-ages (˜100 ka) in the inner U-rich layers of the Sangamonian shells, and 234U/ 238U ratios compatible with a marine origin for U, suggest U-uptake within a short diagenetic interval, when marine waters were still bathing the embedding sediment. Thus, U-series ages on fossil mollusks from such a hyper-arid environment should not differ much from the age of the corresponding marine unit deposition. However, the

Scalable Synthesis of Triple-Core-Shell Nanostructures of TiO2 @MnO2 @C for High Performance Supercapacitors Using Structure-Guided Combustion Waves.

Science.gov (United States)

Shin, Dongjoon; Shin, Jungho; Yeo, Taehan; Hwang, Hayoung; Park, Seonghyun; Choi, Wonjoon

2018-03-01

Core-shell nanostructures of metal oxides and carbon-based materials have emerged as outstanding electrode materials for supercapacitors and batteries. However, their synthesis requires complex procedures that incur high costs and long processing times. Herein, a new route is proposed for synthesizing triple-core-shell nanoparticles of TiO 2 @MnO 2 @C using structure-guided combustion waves (SGCWs), which originate from incomplete combustion inside chemical-fuel-wrapped nanostructures, and their application in supercapacitor electrodes. SGCWs transform TiO 2 to TiO 2 @C and TiO 2 @MnO 2 to TiO 2 @MnO 2 @C via the incompletely combusted carbonaceous fuels under an open-air atmosphere, in seconds. The synthesized carbon layers act as templates for MnO 2 shells in TiO 2 @C and organic shells of TiO 2 @MnO 2 @C. The TiO 2 @MnO 2 @C-based electrodes exhibit a greater specific capacitance (488 F g -1 at 5 mV s -1 ) and capacitance retention (97.4% after 10 000 cycles at 1.0 V s -1 ), while the absence of MnO 2 and carbon shells reveals a severe degradation in the specific capacitance and capacitance retention. Because the core-TiO 2 nanoparticles and carbon shell prevent the deformation of the inner and outer sides of the MnO 2 shell, the nanostructures of the TiO 2 @MnO 2 @C are preserved despite the long-term cycling, giving the superior performance. This SGCW-driven fabrication enables the scalable synthesis of multiple-core-shell structures applicable to diverse electrochemical applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Standardized CSR and climate performance: why is Shell willing, but Hydro reluctant?; Shell; Hydro

Energy Technology Data Exchange (ETDEWEB)

Boasson, Elin Lerum; Wettestad, Joergen

2007-06-15

This report aims to contribute to the ongoing discussion concerning whether CSR merely serves to streamline company rhetoric or also has an influence on actual efforts. We discuss the tangible effects of CSR instruments on the climate-related rules and performances of the two different oil companies Hydro and Shell. First we explore whether similar CSR instruments lead to similar climate-related rules and practices in the two companies. Both Hydro and Shell adhere to the Global Compact (GC), the Global Reporting Initiative (GRI), the Carbon Disclosure Project (CDP) and the Global Gas Flaring Reduction Public-Private Partnership (GGFR). The report concludes that the GC has not rendered any tangible effects in either of the companies. Concerning the other instruments, Hydro has only followed the instrument requirements that fit their initial approach, and refrained from all deviating requirements. Shell has been more malleable, but we have noted few effects on the actual emissions and business portfolio resulting from the instrument adherence. Second, we assess how the differing results of the similar CSR portfolio may be explained. The reluctant attitude of the leaders in Hydro and the strong CSR motivation of Shell's executives result in significant differences. Hydro executives are able to constrain the effects of the instrument adherence. With Shell we note the opposite pattern: Its leaders promoted the instruments to be translated into internal rules, but a general lack of hierarchical structures hinders them from governing the conduct of various sub-organisations. The very diversity of the Shell culture helps to explain why the efforts of its executives have resulted in limited impact. The strength of the Hydro culture makes the corporation resistant to the instruments. Moreover, Hydro is strikingly shielded by virtue of its strong position in Norway. In contrast, Shell is more strongly affected by the global field of petroleum and the global field of CSR

HR Del REMNANT ANATOMY USING TWO-DIMENSIONAL SPECTRAL DATA AND THREE-DIMENSIONAL PHOTOIONIZATION SHELL MODELS

International Nuclear Information System (INIS)

Moraes, Manoel; Diaz, Marcos

2009-01-01

The HR Del nova remnant was observed with the IFU-GMOS at Gemini North. The spatially resolved spectral data cube was used in the kinematic, morphological, and abundance analysis of the ejecta. The line maps show a very clumpy shell with two main symmetric structures. The first one is the outer part of the shell seen in Hα, which forms two rings projected in the sky plane. These ring structures correspond to a closed hourglass shape, first proposed by Harman and O'Brien. The equatorial emission enhancement is caused by the superimposed hourglass structures in the line of sight. The second structure seen only in the [O III] and [N II] maps is located along the polar directions inside the hourglass structure. Abundance gradients between the polar caps and equatorial region were not found. However, the outer part of the shell seems to be less abundant in oxygen and nitrogen than the inner regions. Detailed 2.5-dimensional photoionization modeling of the three-dimensional shell was performed using the mass distribution inferred from the observations and the presence of mass clumps. The resulting model grids are used to constrain the physical properties of the shell as well as the central ionizing source. A sequence of three-dimensional clumpy models including a disk-shaped ionization source is able to reproduce the ionization gradients between polar and equatorial regions of the shell. Differences between shell axial ratios in different lines can also be explained by aspherical illumination. A total shell mass of 9 x 10 -4 M sun is derived from these models. We estimate that 50%-70% of the shell mass is contained in neutral clumps with density contrast up to a factor of 30.

Commissioning of the 4 K Outer Cryostat for the CUORE Experiment

CERN Document Server

Ferri, E; Biassoni, M; Bucci, C; Ceruti, G; Chiarini, A; Clemenza, M; Cremonesi, O; Datskov, V; Dossena, S; Faverzani, M; Franceschi, M A; Gaigher, R; Gorla, P; Guetti, M; Ligi, C; Napolitano, T; Nucciotti, A; Pelosi, A; Perego, M; Previtali, E; Sisti, M; Taffarello, L; Terranova, F

2014-01-01

The Cryogenic Underground Observatory for Rare Events (CUORE) is a 1-ton scale bolometric experiment. The CUORE detector is an array of 988 TeO crystals arranged in a cylindrical, compact, and granular structure of 19 towers. These detectors will need a base temperature lower than 10 mK in order to meet the performance specifications. To cool the CUORE detector, a large cryogen free cryostat with five pulse tubes and one custom designed high power dilution refrigerator has been designed. The three vessels that form the outer shell of the CUORE cryostat were produced in 2012 and are now assembled in the Gran Sasso National Laboratories (LNGS). We report here the detailed description of the 4 K outer cryostat for the CUORE experiment together with the results of the validation tests done at the production site in 2012 and of the first commissioning to 4 K at LNGS in 2013.

A new thermoplastic resin shell for immobilization of patients receiving high-dose-rate intracavitary irradiation for rectal cancer

International Nuclear Information System (INIS)

Kamikonya, Norihiko; Hishikawa, Yoshio; Kurisu, Koichi; Taniguchi, Midori; Miura, Takashi

1990-01-01

An adjustable immobilizing shell, made of thermoplastic resin (Kurare Shell Filter, KSL) was developed for stabilizing the source during radiotherapy. A piece of KSF was cut to about 15 x 30 cm in size. The KSF was heated at 70-80deg C to soften up. It was kept at room temperature until it cooled to 40deg C. A colonoscope was used to determine the source position in patients being in a left lateral position on the table of the simulator. A piece of KSF was then molded around the patient to fit it over the gluteofemoral region in conformity with the body curvature. The position of the anus was confirmed and marked on the KSF. A cold towel was applied to the shell to harden it rapidly. When the KSF became transparent and hard, it was detached from the patient. A hole was made to insert the outer tube of the radiation source. A cylinder for immobilizing the outer tube was attached. The outer tube of the radiation source was inserted into the patient lying in a left lateral position on the radiotherapy couch. The shell was placed over the outer tube and hold in position on the patient using an elastic tape. The inner tube with its dummy source was introduced into the outer tube, and the source position was fluoroscopically determined. The shell and the inner tube were immobilized with a tape and irradiation was commenced. The newly developed shell was clinically used in 5 patients. The movement of the source during radiotherapy was compared with that in 5 other patients not using the shell. There were no significant differences in irradiation time between the groups, The movement of the source per unit time varied between 0 and 0.13 with a mean of 0.05 in the shell group and 0.09 and 0.60 with a mean of 0.48 in the non-shell group, with statistically significant difference. (N.K.)

Ag@ZnO core-shell nanoparticles study by first principle: The structural, magnetic and optical properties

Energy Technology Data Exchange (ETDEWEB)

Cheng, Hai-Xia [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Xiao-Xu [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Computing Center, Beijing 100094 (China); Hu, Yao-Wen [Department of Physics, Tsinghua University, Beijing 100084 (China); Song, Hong-Quan; Huo, Jin-Rong; Li, Lu [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China); Qian, Ping, E-mail: ustbqianp@163.com [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China); Song, Yu-Jun [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China)

2016-12-15

Ag@ZnO core-shell nanoparticles of around 72 atoms have been investigated by the density functional theory, revealing proving for the first time that the core-shell structure exhibits a shrinkage phenomenon from outer shell in agreement with the other studies in literatures. Our calculations predict that the Ag@ZnO core-shell structure is a ferromagnetic spin polarized state, and the magnetism mainly stems from the spin splitting of 2p electrons of O atoms. In addition, the total and partial DOS of Ag@ZnO indicate that the nanostructure is a half-metallic nanoparticle and has the characters of the p-type semiconductor. Furthermore, the optical properties calculations show that the absorption edge of Ag@ZnO have a red shift and good photocatalysis compare to that of the bulk ZnO. These results of the Ag@ZnO core-shell structure obtain a well agreement with the experimental measurement. - Graphical abstract: Geometric structure of (a) Ag@ZnO core-shell nanostructure; (b) the core of Ag; (c) the shell of ZnO The core-shell nanoparticle Ag@ZnO contains Ag inner core of radius of 4 Å and ZnO outer shell with thickness of 2 Å. Ag@ZnO core-shell nanoparticles of around 72 atoms have been proved for the first time that the core-shell structure exhibit a shrinkage phenomenon from outer shell. Our calculations predict that the Ag@ZnO core-shell structure is a half-metallic nanoparticle and has the characters of the p-type semiconductor. The absorption edge of Ag@ZnO have a red shift and get good photo-catalysis compare to that of the bulk ZnO.

Core-Shell Composite Fibers for High-Performance Flexible Supercapacitor Electrodes.

Science.gov (United States)

Lu, Xiaoyan; Shen, Chen; Zhang, Zeyang; Barrios, Elizabeth; Zhai, Lei

2018-01-31

Core-shell nanofibers containing poly(acrylic acid) (PAA) and manganese oxide nanoparticles as the core and polypyrrole (PPy) as the shell were fabricated through electrospinning the solution of PAA and manganese ions (PAA/Mn 2+ ). The obtained nanofibers were stabilized by Fe 3+ through the interaction between Fe 3+ ions and carboxylate groups. Subsequent oxidation of Mn 2+ by KMnO 4 produced uniform manganese dioxide (MnO 2 ) nanoparticles in the fibers. A PPy shell was created on the fibers by immersing the fibers in a pyrrole solution where the Fe 3+ ions in the fiber polymerized the pyrrole on the fiber surfaces. In the MnO 2 @PAA/PPy core-shell composite fibers, MnO 2 nanoparticles function as high-capacity materials, while the PPy shell prevents the loss of MnO 2 during the charge/discharge process. Such a unique structure makes the composite fibers efficient electrode materials for supercapacitors. The gravimetric specific capacity of the MnO 2 @PAA/PPy core-shell composite fibers was 564 F/g based on cyclic voltammetry curves at 10 mV/s and 580 F/g based on galvanostatic charge/discharge studies at 5 A/g. The MnO 2 @PAA/PPy core-shell composite fibers also present stable cycling performance with 100% capacitance retention after 5000 cycles.

Summary compilation of shell element performance versus formulation.

Energy Technology Data Exchange (ETDEWEB)

Heinstein, Martin Wilhelm; Hales, Jason Dean (Idaho National Laboratory, Idaho Falls, ID); Breivik, Nicole L.; Key, Samuel W. (FMA Development, LLC, Great Falls, MT)

2011-07-01

This document compares the finite element shell formulations in the Sierra Solid Mechanics code. These are finite elements either currently in the Sierra simulation codes Presto and Adagio, or expected to be added to them in time. The list of elements are divided into traditional two-dimensional, plane stress shell finite elements, and three-dimensional solid finite elements that contain either modifications or additional terms designed to represent the bending stiffness expected to be found in shell formulations. These particular finite elements are formulated for finite deformation and inelastic material response, and, as such, are not based on some of the elegant formulations that can be found in an elastic, infinitesimal finite element setting. Each shell element is subjected to a series of 12 verification and validation test problems. The underlying purpose of the tests here is to identify the quality of both the spatially discrete finite element gradient operator and the spatially discrete finite element divergence operator. If the derivation of the finite element is proper, the discrete divergence operator is the transpose of the discrete gradient operator. An overall summary is provided from which one can rank, at least in an average sense, how well the individual formulations can be expected to perform in applications encountered year in and year out. A letter grade has been assigned albeit sometimes subjectively for each shell element and each test problem result. The number of A's, B's, C's, et cetera assigned have been totaled, and a grade point average (GPA) has been computed, based on a 4.0-system. These grades, combined with a comparison between the test problems and the application problem, can be used to guide an analyst to select the element with the best shell formulation.

Preparation, Characterization and Performance of Conch Ceramics Added With Shell

Directory of Open Access Journals (Sweden)

Wang Qingyu

2016-01-01

Full Text Available The conch ceramics bodies with different ratios were prepared by compression moulding technology using shell, kaolin, and calcium oxide etc. as the raw materials, and then calcined at the high temperature to obtain the conch ceramics. The effects of raw material ratios and calcination temperatures on the performance of conch ceramics were investigated by rotational viscometer, vernier caliper, digital display whiteness meter, thermal analyzer, and Fourier transform infrared spectrometer(FT-IR. The results indicated that the viscosity, line shrinkage rate, and whiteness of the conch ceramics were 1.29 Pa·s, 17.9%, and 54.1%, respectively, when the content of the shell powder was 20 wt% and kaolin was 65 wt%. The density of the conch ceramics was the largest (3.8 g/cm3 when calcination temperature was 1200 °C. The results of FT-IR spectrum showed that the addition of the shell powders changed the structure of the ceramic body, which improved the performance of the conch ceramics.

Chemical and biological effects of β-decay and inner shell ionization in biomolecules

International Nuclear Information System (INIS)

Stoecklin, G.

1979-01-01

Tritium and iodine-125, and the Auger effect either caused by the EC-decay of 125 I or by the inner shell vacancy created selectively by mono-energetic X-ray are reviewed in this paper. The specifically labelled precursors to bound 3 H large biomolecules were prepared by conventional syntheses, and then incorporated into the DNA of proliferating cells. The effects like DNA strand breaks or mutational changes are likely to be affected by the localization of the carbonium ions in biological molecules. In contrast to lethality, it was demonstrated that 3 H transmutation effect contributed to DNA strand breaks and played a key role in producing genetic effects. The decay of 3 H in uracil-5- 3 H in the DNA of E. coli was about 7 times as mutagenic as that in uracil-6- 3 H, and 500-fold greater in bacteriophage S13. Drastic chemical consequences are associated with the Auger effect occurring as a possible relaxation process whenever inner shell ionization is initiated. When the vacancy is filled by an electron from an outer shell, the bond energy difference between inner shell electron and outer shell electron is released either in the form of an X-ray fluorescence photon or it can be transmitted to another outer electron which is then ejected. The radioactive decay in specifically labelled biomolecules or the inner shell ionization in heavy constituent atoms caused by resonant X-ray are relevant to a) selective microsurgery in biological macromolecules for the correlation of biological and chemical functions, b) radiotoxicity estimation, and c) radiation therapy. (Yamashita, S.)

Nanocellulose Derivative/Silica Hybrid Core-Shell Chiral Stationary Phase: Preparation and Enantioseparation Performance

Directory of Open Access Journals (Sweden)

Xiaoli Zhang

2016-05-01

Full Text Available Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs were characterized and packed into columns, and their enantioseparation performance was evaluated by high performance liquid chromatography. The results showed that CPMs exhibited uniform surface morphology and core-shell structures. Various types of chiral compounds were efficiently separated under normal and reversed phase mode. Moreover, chloroform and tetrahydrofuran as mobile phase additives could obviously improve the resolution during the chiral separation processes. CPMs still have good chiral separation property when eluted with solvent systems with a high content of tetrahydrofuran and chloroform, which proved the high solvent resistance of this new material.

Nano-engineering of three-dimensional core/shell nanotube arrays for high performance supercapacitors

Science.gov (United States)

Grote, Fabian; Wen, Liaoyong; Lei, Yong

2014-06-01

Large-scale arrays of core/shell nanostructures are highly desirable to enhance the performance of supercapacitors. Here we demonstrate an innovative template-based fabrication technique with high structural controllability, which is capable of synthesizing well-ordered three-dimensional arrays of SnO2/MnO2 core/shell nanotubes for electrochemical energy storage in supercapacitor applications. The SnO2 core is fabricated by atomic layer deposition and provides a highly electrical conductive matrix. Subsequently a thin MnO2 shell is coated by electrochemical deposition onto the SnO2 core, which guarantees a short ion diffusion length within the shell. The core/shell structure shows an excellent electrochemical performance with a high specific capacitance of 910 F g-1 at 1 A g-1 and a good rate capability of remaining 217 F g-1 at 50 A g-1. These results shall pave the way to realize aqueous based asymmetric supercapacitors with high specific power and high specific energy.

X-ray backlighting requirements for the double-shell target

International Nuclear Information System (INIS)

Larsen, J.T.

1980-01-01

We have analyzed one specific NOVA double-shell target design and have determined the x-ray energies required for probing the performance of the implosion. It is virtually impossible to study the compression of the fuel or the motion of the inner pusher. An x-ray energy of about 9 keV appears to be ideal for measuring the behavior of the outer TaCOH shell for the majority of its travel. However, it would be advantageous to have an x-ray source of about 25 keV to measure the contact between the two shells. Development of narrowband x-ray line sources are more desirable than broadband continuum sources since the intensity per keV is many times greater in the line. Intensities of the probes are determined by the self-emission levels of the target capsule. For the 9 keV line source, an intensity of upwards to 10 15 keV/keV/sh/cm 2 /sr is required with a source area of about 0.01 cm 2

Improving the performance parameters of metal cylindrical grid shell ...

African Journals Online (AJOL)

Improving the performance parameters of metal cylindrical grid shell structures. ... Finite element models are designed taking into account minimization of production and ... The force factors and deformation parameters of the basic circuits of a ...

Double shell planar experiments on OMEGA

Science.gov (United States)

Dodd, E. S.; Merritt, E. C.; Palaniyappan, S.; Montgomery, D. S.; Daughton, W. S.; Schmidt, D. W.; Cardenas, T.; Wilson, D. C.; Loomis, E. N.; Batha, S. H.; Ping, Y.; Smalyuk, V. A.; Amendt, P. A.

2017-10-01

The double shell project is aimed at fielding neutron-producing capsules at the National Ignition Facility (NIF), in which an outer low-Z ablator collides with an inner high-Z shell to compress the fuel. However, understanding these targets experimentally can be challenging when compared with conventional single shell targets. Halfraum-driven planar targets at OMEGA are being used to study physics issues important to double shell implosions outside of a convergent geometry. Both VISAR and radiography through a tube have advantages over imaging through the hohlraum and double-shell capsule at NIF. A number physics issues are being studied with this platform that include 1-d and higher dimensional effects such as defect-driven hydrodynamic instabilities from engineering features. Additionally, the use of novel materials with controlled density gradients require study in easily diagnosed 1-d systems. This work ultimately feeds back into the NIF capsule platform through manufacturing tolerances set using data from OMEGA. Supported under the US DOE by the LANS, LLC under contract DE-AC52-06NA25396. LA-UR-17-25386.

Performance Analysis of Doubly Excited Brushless Generator with Outer Rotor for Wind Power Application

Directory of Open Access Journals (Sweden)

Yingchao Zhang

2012-09-01

Full Text Available In this paper, a novel doubly excited brushless generator (DEBG with outer radial laminated magnetic barrier rotor (RLMB-rotor for wind power application was designed and analyzed. The DEBG has 10 rotor pole numbers with outer rotor. Its performance is investigated using the 2D transient finite element method. The magnetic fields, torque capability, end winding voltage characteristics, radial magnetic force and energy efficiency were analyzed. All studies in this paper show that the simplicity, reliability, high efficiency and low vibration and noise of the DEBG with outer rotor are attractive for variable speed constant frequency (VSCF wind power generation system.

Stability of generic thin shells in conformally flat spacetimes

Energy Technology Data Exchange (ETDEWEB)

Amirabi, Z. [Eastern Mediterranean Univ., Gazimagusa (Turkey). Dept. of Physics

2017-07-15

Some important spacetimes are conformally flat; examples are the Robertson-Walker cosmological metric, the Einstein-de Sitter spacetime, and the Levi-Civita-Bertotti-Robinson and Mannheim metrics. In this paper we construct generic thin shells in conformally flat spacetime supported by a perfect fluid with a linear equation of state, i.e., p = ωσ. It is shown that, for the physical domain of ω, i.e., 0 < ω ≤ 1, such thin shells are not dynamically stable. The stability of the timelike thin shells with the Mannheim spacetime as the outer region is also investigated. (orig.)

Two-dimensional perturbations of the accelerated motion of inhomogeneous gas layers and shells in the interstellar medium

Science.gov (United States)

Krasnobaev, K. V.; Kotova, G. Yu.; Tagirova, R. R.

2015-03-01

The evolution of perturbations in a two-layer spherical shell and a plane layer with a two-step density distribution has been simulated numerically. The clumps formed by instability are shown to have qualitatively different structures, depending on the ratio of the densities in the inner and outer layers of the shell. Inhomogeneities bordered by a dense gas are formed in shells with an outwardly decreasing density. If, however, a denser gas is in the outer layer, then cores surrounded by a more rarefied material appear. These results are used to analyze the expansion of the HII region RCW 82. Since the inhomogeneities observed in the 13CO emission in the outer parts of this region have sharply delineated boundaries, our calculations argue for the model of the expansion of a shell with an outwardly decreasing density. The interaction of an accelerating shell with clumps in front of it has also been investigated. The deformations of a clump during its penetration into the shell and the formation of a groove in the shell gradually fillingwith a cold gas have been revealed. Thereafter, the shell material collapses to form a cumulative jet. As applied to the HII region RCW 82, we conclude that the existence of jets is possible if there are inhomogeneities with a scale of ˜1018 cm in the interstellar medium. The lack of data on such jet flows at the boundary of this region is an additional argument for the model where the inhomogeneous structure of the boundaries is attributable to the development of Rayleigh-Taylor instability.

Shell Inspection History and Current CMM Inspection Efforts

Energy Technology Data Exchange (ETDEWEB)

Montano, Joshua Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-01-26

The following report provides a review of past and current CMM Shell Inspection efforts. Calibration of the Sheffield rotary contour gauge has expired and the primary inspector, Matthew Naranjo, has retired. Efforts within the Inspection team are transitioning from maintaining and training new inspectors on Sheffield to off-the-shelf CMM technology. Although inspection of a shell has many requirements, the scope of the data presented in this report focuses on the inner contour, outer contour, radial wall thickness and mass comparisons.

Effect of shells on photoluminescence of aqueous CdTe quantum dots

International Nuclear Information System (INIS)

Yuan, Zhimin; Yang, Ping

2013-01-01

Graphical abstract: Size-tunable CdTe coated with several shells using an aqueous solution synthesis. CdTe/CdS/ZnS quantum dots exhibited high PL efficiency up to 80% which implies the promising applications for biomedical labeling. - Highlights: • CdTe quantum dots were fabricated using an aqueous synthesis. • CdS, ZnS, and CdS/ZnS shells were subsequently deposited on CdTe cores. • Outer ZnS shells provide an efficient confinement of electron and hole inside the QDs. • Inside CdS shells can reduce the strain on the QDs. • Aqueous CdTe/CdS/ZnS QDs exhibited high stability and photoluminescence efficiency of 80%. - Abstract: CdTe cores with various sizes were fabricated in aqueous solutions. Inorganic shells including CdS, ZnS, and CdS/ZnS were subsequently deposited on the cores through a similar aqueous procedure to investigate the effect of shells on the photoluminescence properties of the cores. In the case of CdTe/CdS/ZnS quantum dots, the outer ZnS shell provides an efficient confinement of electron and hole wavefunctions inside the quantum dots, while the middle CdS shell sandwiched between the CdTe core and ZnS shell can be introduced to obviously reduce the strain on the quantum dots because the lattice parameters of CdS is situated at the intermediate-level between those of CdTe and ZnS. In comparison with CdTe/ZnS core–shell quantum dots, the as-prepared water-soluble CdTe/CdS/ZnS quantum dots in our case can exhibit high photochemical stability and photoluminescence efficiency up to 80% in an aqueous solution, which implies the promising applications in the field of biomedical labeling

The outer tracker detector of the HERA-B experiment. Pt. 3. Operation and performance

International Nuclear Information System (INIS)

Albrecht, H.; Bauer, T.S.; Utrecht Univ.; Beck, M.

2006-12-01

In this paper we describe the operation and performance of the HERA-B Outer Tracker, a 112674 channel system of planar drift tube layers. The performance of the HERA-B Outer Tracker system fullfilled all requirements for stable and efficient operation in a hadronic environment, thus confirming the adequacy of the honeycomb drift tube technology and of the front-end readout system. The detector was stably operated with a gas gain of 3 . 10 4 in an Ar/CF 4 /CO 2 (65:35:5) gas mixture, yielding a good efficiency for triggering and track reconstruction, larger than 95 % for tracks with momenta above 5 GeV/c. The hit resolution of the drift cells was 300 to 320 μm and the relative momentum resolution can be described as: σ(p)/p(%) = (1.61 ± 0.02) + (0.0051 ± 0.0006) . p. At the end of the HERA-B running no aging effects in the Outer Tracker cells were observed. (orig.)

Penetration of steady fluid motions into an outer stable layer excited by MHD thermal convection in rotating spherical shells

Science.gov (United States)

Takehiro, Shin-ichi; Sasaki, Youhei

2018-03-01

Penetration of steady magneto-hydrodynamic (MHD) disturbances into an upper strongly stratified stable layer excited by MHD thermal convection in rotating spherical shells is investigated. The theoretical model proposed by Takehiro (2015) is reexamined in the case of steady fluid motion below the bottom boundary. Steady disturbances penetrate into a density stratified MHD fluid existing in the semi-infinite region in the vertical direction. The axis of rotation of the system is tilted with respect to the vertical. The basic magnetic field is uniform and may be tilted with respect to the vertical and the rotation axis. Linear dispersion relation shows that the penetration distance with zero frequency depends on the amplitude of Alfvén wave speed. When Alfvén wave speed is small, viscous diffusion becomes dominant and penetration distance is similar to the horizontal scale of the disturbance at the lower boundary. In contrast, when Alfvén wave speed becomes larger, disturbance can penetrate deeper, and penetration distance becomes proportional to the Alfvén wave speed and inversely proportional to the geometric average of viscous and magnetic diffusion coefficients and to the total horizontal wavenumber. The analytic expression of penetration distance is in good agreement with the extent of penetration of mean zonal flow induced by finite amplitude convection in a rotating spherical shell with an upper stably stratified layer embedded in an axially uniform basic magnetic field. The theory expects that the stable layer suggested in the upper part of the outer core of the earth could be penetrated completely by mean zonal flows excited by thermal/compositional convection developing below the stable layer.

Performance Requirements for the Double Shell Tank (DST) System

International Nuclear Information System (INIS)

SMITH, D.F.

2001-01-01

This document identifies the upper-level Double-Shell Tank (DST) System functions and bounds the associated performance requirements. The functions and requirements are provided along with supporting bases. These functions and requirements, in turn, will be incorporated into specifications for the DST System

Shock absorbing properties of toroidal shells under compression, 3

International Nuclear Information System (INIS)

Sugita, Yuji

1985-01-01

The author has previously presented the static load-deflection relations of a toroidal shell subjected to axisymmetric compression between rigid plates and those of its outer half when subjected to lateral compression. In both these cases, the analytical method was based on the incremental Rayleigh-Ritz method. In this paper, the effects of compression angle and strain rate on the load-deflection relations of the toroidal shell are investigated for its use as a shock absorber for the radioactive material shipping cask which must keep its structural integrity even after accidental falls at any angle. Static compression tests have been carried out at four angles of compression, 10 0 , 20 0 , 50 0 , 90 0 and the applications of the preceding analytical method have been discussed. Dynamic compression tests have also been performed using the free-falling drop hammer. The results are compared with those in the static compression tests. (author)

Core-shell microspheres with porous nanostructured shells for liquid chromatography.

Science.gov (United States)

Ahmed, Adham; Skinley, Kevin; Herodotou, Stephanie; Zhang, Haifei

2018-01-01

The development of new stationary phases has been the key aspect for fast and efficient high-performance liquid chromatography separation with relatively low backpressure. Core-shell particles, with a solid core and porous shell, have been extensively investigated and commercially manufactured in the last decade. The excellent performance of core-shell particles columns has been recorded for a wide range of analytes, covering small and large molecules, neutral and ionic (acidic and basic), biomolecules and metabolites. In this review, we first introduce the advance and advantages of core-shell particles (or more widely known as superficially porous particles) against non-porous particles and fully porous particles. This is followed by the detailed description of various methods used to fabricate core-shell particles. We then discuss the applications of common silica core-shell particles (mostly commercially manufactured), spheres-on-sphere particles and core-shell particles with a non-silica shell. This review concludes with a summary and perspective on the development of stationary phase materials for high-performance liquid chromatography applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulations of Ar gas-puff Z-pinch radiation sources with double shells and central jets on the Z generator

Science.gov (United States)

Tangri, V.; Harvey-Thompson, A. J.; Giuliani, J. L.; Thornhill, J. W.; Velikovich, A. L.; Apruzese, J. P.; Ouart, N. D.; Dasgupta, A.; Jones, B.; Jennings, C. A.

2016-10-01

Radiation-magnetohydrodynamic simulations using the non-local thermodynamic equilibrium Mach2-Tabular Collisional-Radiative Equilibrium code in (r, z) geometry are performed for two pairs of recent Ar gas-puff Z-pinch experiments on the refurbished Z generator with an 8 cm diameter nozzle. One pair of shots had an outer-to-inner shell mass ratio of 1:1.6 and a second pair had a ratio of 1:1. In each pair, one of the shots had a central jet. The experimental trends in the Ar K-shell yield and power are reproduced in the calculations. However, the K-shell yield and power are significantly lower than the other three shots for the case of a double-shell puff of 1:1 mass ratio and no central jet configuration. Further simulations of a hypothetical experiment with the same relative density profile of this configuration, but higher total mass, show that the coupled energy from the generator and the K-shell yield can be increased to levels achieved in the other three configurations, but not the K-shell power. Based on various measures of effective plasma radius, the compression in the 1:1 mass ratio and no central jet case is found to be less because the plasma inside the magnetic piston is hotter and of lower density. Because of the reduced density, and the reduced radiation cooling (which is proportional to the square of the density), the core plasma is hotter. Consequently, for the 1:1 outer-to-inner shell mass ratio, the load mass controls the yield and the center jet controls the power.

MOF@MOF core–shell vs. Janus particles and the effect of strain: potential for guest sorption, separation and sequestration

NARCIS (Netherlands)

Szilagyi, P.A.; Lutz, M.; Gascon, J.; Juan-Alcañiz, J.; van Esch, J.; Kapteijn, F.; Geerlings, H.; Dam, B.; van der Krol, R.

2013-01-01

The effect of strain on core–shell MOFcore@MOFshell particles is discussed and compared with that observed for analogous Janus particles. Whereas Janus particles do not display any effect of strain, the core of fully coated core–shell particles collapsed upon the formation of the outer shell,

Energetic particle drift motions in the outer dayside magnetosphere

International Nuclear Information System (INIS)

Buck, R.M.

1987-12-01

Models of the geomagnetic field predict that within a distance of approximately one earth radius inside the dayside magnetopause, magnetic fields produced by the Chapman-Ferraro magnetopause currents create high-latitude minimum-B ''pockets'' in the geomagnetic field. Drift-shell branching caused by the minimum-B pockets is analyzed and interpreted in terms of an adiabatic shell branching and rejoining process. We examine the shell-branching process for a static field in detail, using the Choe-Beard 1974 magnetospheric magnetic field model. We find that shell branching annd rejoining conserves the particle mirror field B/sub M/, the fieldline integral invariant I, and the directional electron flux j. We determine the spatial extent of the stable trapping regions for the Choe-Beard model. We develop an adiabatic branching map methodology which completely identifies and describes the location of shell-branching points and the adiabatic trajectories of particles on branched shells, for any model field. We employ the map to develop synthetic pitch angle distributions near the dayside magnetopause by adiabatically transforming observed midnight distributions to the dayside. We find that outer dayside lines contain particles moving on branched and unbranched shells, giving rise to distinctive pitch angle distribution features. We find a good correlation between the pitch angles which mark the transition from branched to unbranched shells in the model, and the distinctive features of the OGO-5 distributions. In the morning sector, we observe large flux changes at critical pitch angles which correspond to B-pocket edges in the model. Measurements on inbound passes in the afternoon sector show first the adiabatic particle shadow, then the arrival of fluxes on rejoined shells, then fluxes on unbranced shells - in accord with model predictions. 204 refs., 138 figs., 2 tabs

Biomechanics on the half shell: functional performance influences patterns of morphological variation in the emydid turtle carapace.

Science.gov (United States)

Stayton, C Tristan

2011-09-01

This study uses the carapace of emydid turtles to address hypothesized differences between terrestrial and aquatic species. Geometric morphometrics are used to quantify shell shape, and performance is estimated for two shell functions: shell strength and hydrodynamics. Aquatic turtle shells differ in shape from terrestrial turtle shells and are characterized by lower frontal areas and presumably lower drag. Terrestrial turtle shells are stronger than those of aquatic turtles; many-to-one mapping of morphology to function does not entirely mitigate a functional trade-off between mechanical strength and hydrodynamic performance. Furthermore, areas of morphospace characterized by exceptionally poor performance in either of the functions are not occupied by any emydid species. Though aquatic and terrestrial species show no significant differences in the rate of morphological evolution, aquatic species show a higher lineage density, indicative of a greater amount of convergence in their evolutionary history. The techniques employed in this study, including the modeling of theoretical shapes to assess performance in unoccupied areas of morphospace, suggest a framework for future studies of morphological variation. Copyright © 2011 Elsevier GmbH. All rights reserved.

Axisymmetrical impulsive responses of an infinite circular cylindrical shell filled with liquid

International Nuclear Information System (INIS)

Ujihashi, Sadayuki; Matsumoto, Hiroyuki; Nakahara, Ichiro; Shigeta, Masayuki.

1986-01-01

In this paper, dynamic interaction phenomena on solid and liquid interfaces are discussed. Axisymmetrical responses of an infinite circular cylindrical shell perfectly filled with liquid are analyzed, based on Fluegge's theory for a circular cylindrical shell and the potential theory for the ideal fluid under conditions of the impulsive external band pressure given on the outer surface of the shell. The deflection and the moment of the shell and the pressure in the fluid are evaluated by using the numerical inversion of the Laplace transformation method. The approximate solution for the shell with an equivalent mass on it is analyzed and is evaluated, based on the solution for the solid and liquid interaction. (author)

Fast ignition upon the implosion of a thin shell onto a precompressed deuterium-tritium ball

Science.gov (United States)

Gus'kov, S. Yu.; Zmitrenko, N. V.

2012-11-01

Fast ignition of a precompressed inertial confinement fusion (ICF) target by a hydrodynamic material flux is investigated. A model system of hydrodynamic objects consisting of a central deuterium-tritium (DT) ball and a concentric two-layer shell separated by a vacuum gap is analyzed. The outer layer of the shell is an ablator, while the inner layer consists of DT ice. The igniting hydrodynamic flux forms as a result of laser-driven acceleration and compression of the shell toward the system center. A series of one-dimensional numerical simulations of the shell implosion, the collision of the shell with the DT ball, and the generation and propagation of thermonuclear burn waves in both parts of the system are performed. Analytic models are developed that describe the implosion of a thin shell onto a central homogeneous ball of arbitrary radius and density and the initiation and propagation of a thermonuclear burn wave induced by such an implosion. Application of the solution of a model problem to analyzing the implosion of a segment of a spherical shell in a conical channel indicates the possibility of fast ignition of a spherical ICF target from a conical target driven by a laser pulse with an energy of 500-700 kJ.

Improvement on electrochemical performance by partial replacement of Ru@Pt core-shell nanocatalyst by temperature modification

International Nuclear Information System (INIS)

Chang, Chih-Juei; Lin, Liang-You; Tseng, Fan-Gang

2014-01-01

In this paper, the homemade open-loop reduction system (OLRS), and redox transmetalation method were utilized to produce the core-shell Ru (ruthenium)/Pt (platinum) catalysts on the carbon cloth (CC) for direct methanol fuel cell (DMFC) application. By adjusting pH value and heating to proper temperature of the ionized reduction environment, Pt 4+ can be first converted into Pt 2+ to allow partial Ru replacement with Pt by redox transmetalation and produce Ru@Pt core-shell nanostructures[1]. And we change the reduction temperature to see how it affects the efficiency of the DMFC. The scanning electron microscopic (SEM) top-view micrographs showing that the apparent Ru@Pt nanoparticles successfully deposited on both the inner and outer surfaces of the hydrophilically-treated CC. At high SEM magnification, the small size and high-density distribution of the Ru@Pt nanoparticles were clearly observed on the hydrophilically-treated CC, and much more Pt@Ru catalyst deposit on the CC surface with the sample of 80 °C. The electrosorption charges of hydrogen ion (Q H ) and the peak current density (I P ) of the samples in the cyclic voltammetry (CV) curves. The magnitude of peak current density is positive correlation to the temperature. However, the CO tolerance, indicated that the better CO tolerance contributed to the less Pt replace on Ru cluster, which allow the Ru oxidizing CO to CO 2 efficiently, is negative correlation-- to the temperature. The sample of 50 °C shows the better combination catalyst efficiency between the CO tolerance and the electrochemical performance

Pearl-necklace structures in core-shell molecular brushes: Experiments, Monte Carlo simulations and self-consistent field modeling

NARCIS (Netherlands)

Polotsky, A.; Charlaganov, M.; Xu, Y.P.; Leermakers, F.A.M.; Daoud, M.; Muller, A.H.E.; Dotera, T.; Borisov, O.V.

2008-01-01

We present theoretical arguments and experimental evidence for a longitudinal instability in core-shell cylindrical polymer brushes with a solvophobic inner (core) block and a solvophilic outer (shell) block in selective solvents. The two-gradient self-consistent field Scheutjens-Fleer (SCF-SF)

Dynamic response of aircraft impact of a reactor building with protective shell on independent foundation

International Nuclear Information System (INIS)

Constantopoulos, I.V.; Vardanega, C.; Attalla, I.

1981-01-01

Aircraft impact loading can penalize significantly the design of the equipment in a conventional containment building. An alternative scheme was developed in an attempt to reduce the aircraft impact response. A preliminary study was carried out to investigate the feasibility of the alternative scheme. This study was made in such perspective and for the purpose of comparing the response to aircraft impact of a standard reactor building, to that of a reactor building having an independently founded outer shell. In the second scheme, the outer shell is meant to receive the aircraft impact, so that the load will be transmitted to the reactor building internals only by way of the structure-soil-structure system. In both cases, the aircraft impact was postulated to occur on a linear single degree of freedom oscillator which modeled, approximately, the plastification of the impact area. The soil was considered as a half-space with properties corresponding to a medium stiff soil, and modeled by lumped soil springs and dashpots. The reactor internals, inner shell and protective outer shell were modeled with beam elements and concentrated inertias. In modeling the coupled system, soil-structure interaction and structure-to-structure interaction through the soil were represented by a global stiffness matrix corresponding to the three degrees the freedom of each foundation, i.e. horizontal, vertical and rocking. (orig./HP)

Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

Science.gov (United States)

Preti, Raffaella

2016-01-01

The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large amount of samples must be analyzed fast using reliable and solvent-saving apparatus. The literature hereby described shows how the outstanding performances provided by core-shell particles column on a traditional HPLC instruments are comparable to those obtained with a costly UHPLC instrumentation, making this novel column a promising key tool in food analysis. PMID:27143972

Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure

KAUST Repository

Vanteru, Mahendra Reddy

2016-01-18

Heavy fuel oil (HFO) as a fuel in industrial and power generation plants ensures the availability of energy at economy. Coke and cenosphere emissions from HFO combustion need to be controlled by particulate control equipment such as electrostatic precipitators, and collection effectiveness is impacted by the properties of these particulates. The cenosphere formation is a function of HFO composition, which varies depending on the source of the HFO. Numerical modelling of the cenosphere formation mechanism presented in this paper is an economical method of characterising cenosphere formation potential for HFO in comparison to experimental analysis of individual HFO samples, leading to better control and collection. In the present work, a novel numerical model is developed for understanding the global cenosphere formation mechanism. The critical diameter of the cenosphere is modelled based on the balance between two pressures developed in an HFO droplet. First is the pressure (Prpf) developed at the interface of the liquid surface and the inner surface of the accumulated coke due to the flow restriction of volatile components from the interior of the droplet. Second is the pressure due to the outer shell strength (PrC) gained from van der Walls energy of the coke layers and surface energy. In this present study it is considered that when PrC ≥ Prpf the outer shell starts to harden. The internal motion in the shell layer ceases and the outer diameter (DSOut) of the shell is then fixed. The entire process of cenosphere formation in this study is analysed in three phases: regression, shell formation and hardening, and post shell hardening. Variations in pressures during shell formation are analysed. Shell (cenosphere) dimensions are evaluated at the completion of droplet evaporation. The rate of fuel evaporation, rate of coke formation and coke accumulation are analysed. The model predicts shell outer diameters of 650, 860 and 1040 µm, and inner diameters are 360, 410

Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure

KAUST Repository

Vanteru, Mahendra Reddy; Rahman, Mustafa M.; Gandi, Appala; Elbaz, Ayman M.; Schrecengost, Robert A.; Roberts, William L.

2016-01-01

Heavy fuel oil (HFO) as a fuel in industrial and power generation plants ensures the availability of energy at economy. Coke and cenosphere emissions from HFO combustion need to be controlled by particulate control equipment such as electrostatic precipitators, and collection effectiveness is impacted by the properties of these particulates. The cenosphere formation is a function of HFO composition, which varies depending on the source of the HFO. Numerical modelling of the cenosphere formation mechanism presented in this paper is an economical method of characterising cenosphere formation potential for HFO in comparison to experimental analysis of individual HFO samples, leading to better control and collection. In the present work, a novel numerical model is developed for understanding the global cenosphere formation mechanism. The critical diameter of the cenosphere is modelled based on the balance between two pressures developed in an HFO droplet. First is the pressure (Prpf) developed at the interface of the liquid surface and the inner surface of the accumulated coke due to the flow restriction of volatile components from the interior of the droplet. Second is the pressure due to the outer shell strength (PrC) gained from van der Walls energy of the coke layers and surface energy. In this present study it is considered that when PrC ≥ Prpf the outer shell starts to harden. The internal motion in the shell layer ceases and the outer diameter (DSOut) of the shell is then fixed. The entire process of cenosphere formation in this study is analysed in three phases: regression, shell formation and hardening, and post shell hardening. Variations in pressures during shell formation are analysed. Shell (cenosphere) dimensions are evaluated at the completion of droplet evaporation. The rate of fuel evaporation, rate of coke formation and coke accumulation are analysed. The model predicts shell outer diameters of 650, 860 and 1040 µm, and inner diameters are 360, 410

Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure

Science.gov (United States)

Reddy, Vanteru M.; Rahman, Mustafa M.; Gandi, Appala N.; Elbaz, Ayman M.; Schrecengost, Robert A.; Roberts, William L.

2016-01-01

Heavy fuel oil (HFO) as a fuel in industrial and power generation plants ensures the availability of energy at economy. Coke and cenosphere emissions from HFO combustion need to be controlled by particulate control equipment such as electrostatic precipitators, and collection effectiveness is impacted by the properties of these particulates. The cenosphere formation is a function of HFO composition, which varies depending on the source of the HFO. Numerical modelling of the cenosphere formation mechanism presented in this paper is an economical method of characterising cenosphere formation potential for HFO in comparison to experimental analysis of individual HFO samples, leading to better control and collection. In the present work, a novel numerical model is developed for understanding the global cenosphere formation mechanism. The critical diameter of the cenosphere is modelled based on the balance between two pressures developed in an HFO droplet. First is the pressure (Prpf) developed at the interface of the liquid surface and the inner surface of the accumulated coke due to the flow restriction of volatile components from the interior of the droplet. Second is the pressure due to the outer shell strength (PrC) gained from van der Walls energy of the coke layers and surface energy. In this present study it is considered that when PrC ≥ Prpf the outer shell starts to harden. The internal motion in the shell layer ceases and the outer diameter (DSOut) of the shell is then fixed. The entire process of cenosphere formation in this study is analysed in three phases: regression, shell formation and hardening, and post shell hardening. Variations in pressures during shell formation are analysed. Shell (cenosphere) dimensions are evaluated at the completion of droplet evaporation. The rate of fuel evaporation, rate of coke formation and coke accumulation are analysed. The model predicts shell outer diameters of 650, 860 and 1040 µm, and inner diameters are 360, 410

Double-shell target fabrication workshop-2016 report

Energy Technology Data Exchange (ETDEWEB)

Wang, Y. Morris [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oertel, John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Farrell, Michael [General Atomics, San Diego, CA (United States); Baumann, Ted [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Huang, Haibo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nikroo, Abbas [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-01-10

On June 30, 2016, over 40 representatives from Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), General Atomics (GA), Laboratory for Laser Energetics (LLE), Schafer Corporation, and NNSA headquarter attended a double-shell (DS) target fabrication workshop at Livermore, California. Pushered-single-shell (PSS) and DS metalgas platforms potentially have a large impact on programmatic applications. The goal of this focused workshop is to bring together target fabrication scientists, physicists, and designers to brainstorm future PSS and DS target fabrication needs and strategies. This one-day workshop intends to give an overall view of historical information, recent approaches, and future research activities at each participating organization. Five topical areas have been discussed that are vital to the success of future DS target fabrications, including inner metal shells, foam spheres, outer ablators, fill tube assembly, and metrology.

Synthesis and utilization of catalytically cracked cashew nut shell liquid in a diesel engine

KAUST Repository

Vedharaj, S.; Vallinayagam, R.; Yang, W.M.; Saravanan, C.G.; Roberts, William L.

2015-01-01

In this study, CNSL (Cashew nut shell liquid), an economically viable feedstock among the other contemporary resources, has been considered as an appropriate source of alternate fuel. Herein, CNSL was extracted from cashew nut outer shell, a waste product, through a unique approach of steam treatment process followed by mechanical crushing technique. In contrast to the past studies that have attempted to use unprocessed CNSL directly as substitute for diesel, this study has resorted to use processed CNSL by cracking it using zeolite catalyst. Thus, both the extraction of CNSL from cashew nut outer shell and processing of it through catalytic cracking process to help synthesize CC-CNSL (catalytically cracked CNSL) are different, which underscores the significance of the current work. In wake of adopting such distinct methodologies with fuel characterization, the properties of CC-CNSL such as viscosity and calorific value were figured out to be improved. Subsequently, CC-CNSL20 (20% CC-CNSL and 80% diesel) was tested at different fuel injection pressure such as 200 bar, 235 bar, 270 bar and 300 bar so as to optimize its use in a single cylinder diesel engine. From the engine experimental study, CC-CNSL20 was found to evince better engine performance than diesel and the composite emissions of CO (carbon monoxide), HC (hydrocarbon), NOX (oxides of nitrogen) and smoke, computed based on ISO 8178 D2 standard test cycle, were found to be better than diesel and incompliance with the legislative norms for genset.

Synthesis and utilization of catalytically cracked cashew nut shell liquid in a diesel engine

KAUST Repository

Vedharaj, S.

2015-09-30

In this study, CNSL (Cashew nut shell liquid), an economically viable feedstock among the other contemporary resources, has been considered as an appropriate source of alternate fuel. Herein, CNSL was extracted from cashew nut outer shell, a waste product, through a unique approach of steam treatment process followed by mechanical crushing technique. In contrast to the past studies that have attempted to use unprocessed CNSL directly as substitute for diesel, this study has resorted to use processed CNSL by cracking it using zeolite catalyst. Thus, both the extraction of CNSL from cashew nut outer shell and processing of it through catalytic cracking process to help synthesize CC-CNSL (catalytically cracked CNSL) are different, which underscores the significance of the current work. In wake of adopting such distinct methodologies with fuel characterization, the properties of CC-CNSL such as viscosity and calorific value were figured out to be improved. Subsequently, CC-CNSL20 (20% CC-CNSL and 80% diesel) was tested at different fuel injection pressure such as 200 bar, 235 bar, 270 bar and 300 bar so as to optimize its use in a single cylinder diesel engine. From the engine experimental study, CC-CNSL20 was found to evince better engine performance than diesel and the composite emissions of CO (carbon monoxide), HC (hydrocarbon), NOX (oxides of nitrogen) and smoke, computed based on ISO 8178 D2 standard test cycle, were found to be better than diesel and incompliance with the legislative norms for genset.

Novel chiral core-shell silica microspheres with trans-(1R,2R)-diaminocyclohexane bridged in the mesoporous shell: synthesis, characterization and application in high performance liquid chromatography.

Science.gov (United States)

Wu, Xiabing; You, Linjun; Di, Bin; Hao, Weiqiang; Su, Mengxiang; Gu, Yu; Shen, Lingling

2013-07-19

Novel chiral core-shell silica microspheres with trans-(1R,2R)-diaminocyclohexane (DACH) moiety bridged in the mesoporous shell were synthesized using layer-by-layer method. The chiral mesoporous shell around the nonporous silica core was formed by the co-condensation of N,N'-bis-[(triethoxysilyl)propyl]-trans-(1R,2R)-bis-(ureido)-cyclohexane (DACH-BS) and tetraethoxysilane (TEOS) using octadecyltrimethylammonium chloride (C18TMACl) and triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer (P123) as the templates. The functionalized core-shell silica microspheres were characterized and tested as chiral stationary phases for high performance liquid chromatography (HPLC). R/S-1,1'-bi-2,2'-naphthol, R/S-6,6'-dibromo-1,1'-bi-2-naphthol and R/S-1,1'-bi-2,2'-phenanthrol were enantioseparated rapidly on the column packed with the DACH core-shell silica particles. Moreover, the column packed with core-shell particles exhibited better performance than the column packed with the DACH functionalized periodic mesoporous organosilicas. Copyright © 2013 Elsevier B.V. All rights reserved.

A novel magnetic core-shell nanocomposite Fe3O4@chitosan@ZnO for the green synthesis of 2-benzimidazoles

Science.gov (United States)

Tian, Fei; Niu, Libo; Chen, Bo; Gao, Xuejia; Lan, Xingwang; Huo, Li; Bai, Guoyi

2017-10-01

A novel magnetic core-shell nanocomposite Fe3O4@Chitosan@ZnO was successfully prepared by in situ chemical precipitation method. It has a clear core-shell structure with magnetic Fe3O4 (about 160 nm in diameter) as core, chitosan as the inner shell, and ZnO as the outer shell, as demonstrated by the transmission electron microscopy and the related elemental mapping. Moreover, this nanocomposite has high magnetization (43.6 emu g-1) so that it can be easily separated from the reaction mixture within 4 s by an external magnetic field. The introduction of the natural chitosan shell, instead of the conventional SiO2 shell, and its combination with the active ZnO ensures this novel nanocomposite green character and good catalytic performance in the synthesis of 2-benzimidazoles with moderate to excellent isolated yields at room temperature. Notably, it can be recycled seven times without appreciable loss of its initial catalytic activity, demonstrating its good stability and making it an attractive candidate for the green synthesis of 2-benzimidazoles. [Figure not available: see fulltext.

Carbon-shell-constrained silicon cluster derived from Al-Si alloy as long-cycling life lithium ion batteries anode

Science.gov (United States)

Su, Junming; Zhang, Congcong; Chen, Xiang; Liu, Siyang; Huang, Tao; Yu, Aishui

2018-03-01

Although silicon is the most promising anode material for Li-ion batteries, large volume expansion during lithiation and delithiation is the main obstacle limiting the commercial application of silicon anodes. There are two ways to alleviate volume expansion and prevent further pulverization of a Si anode: fabrication of a rational nanostructure possessing void spaces and uniform distribution of the conducting sites, without a good balance effect in mitigating the limiting factors and enhancing battery performance. In this paper, we propose a novel nanostructure - a carbon-shell-constrained Si cluster (Si/C shell) with both adequate void space and good distribution of electrical contact sites to guarantee homogeneous lithiation in the initial cycle. Benefiting from the ability to maintain electrical conductivity of the outer carbon shell, even after cluster fragmentation, the Si/C shell synthesized from low-cost commercial Al-Si alloy spheres can deliver 0.03% capacity loss from 100th to 1000th cycles at a current density of 1 A g-1. The Si/C shell sample with the dual functional structure mentioned above can also maintain its own nanostructure during cycling and deliver excellent rate performance. It is a concise and scalable strategy which can simplify the preparation of other alloy anode materials for Li-ion batteries.

Silver-nickel oxide core-shell nanoflower arrays as high-performance anode for lithium-ion batteries

Science.gov (United States)

Zhao, Wenjia; Du, Ning; Zhang, Hui; Yang, Deren

2015-07-01

We demonstrate the synthesis of Ag-NiO core-shell nanoflower arrays via a one-step solution-immersion process and subsequent RF-sputtering method. The aligned Ag nanoflower arrays on copper substrate are prepared by a facile displacement reaction in absence of any surfactant at a mild temperature. When used as anode materials for lithium-ion batteries, the Ag-NiO core-shell nanoflower arrays show better cycling performance and higher capacity than the planar NiO electrodes. The improved performance should be attributed to the core-shell structures that can enhance the conductivity and accommodate the volume change during the charge-discharge process.

A study of the valence shell photoelectron and photoabsorption spectra of CF3SF5

International Nuclear Information System (INIS)

Holland, D M P; Shaw, D A; Walker, I C; McEwen, I J; Apra, E; Guest, M F

2005-01-01

The outer valence shell photoelectron spectrum of CF 3 SF 5 has been studied experimentally and theoretically. Synchrotron radiation has been used to record angle-resolved outer valence shell photoelectron spectra of CF 3 SF 5 in the photon energy range 18-60 eV. These spectra have allowed photoelectron asymmetry parameters and branching ratios to be derived. The Outer Valence Green's Function approach has been employed to calculate the molecular orbital configuration and associated binding energies. A charge distribution analysis has also been obtained. Assignments have been proposed for the peaks observed in the photoelectron spectrum. The absolute photoabsorption cross section of CF 3 SF 5 has been measured from threshold to 40 eV, and strongly resembles that of SF 6 . Assignments, involving intravalence transitions, have been proposed for some of the principal features appearing in the photoabsorption spectrum of CF 3 SF 5

Gold nanorod@iron oxide core-shell heterostructures: synthesis, characterization, and photocatalytic performance.

Science.gov (United States)

Li, Yue; Zhao, Junwei; You, Wenlong; Cheng, Danhong; Ni, Weihai

2017-03-17

Iron oxides are directly coated on the surface of cetyl-trimethylammonium bromide (CTAB)-capped gold nanorods (AuNRs) in aqueous solutions at room temperature, which results in AuNR@Fe 2 O 3 , AuNR@Fe 3 O 4 , and AuNR@Fe 2 O 3 @Fe 3 O 4 core-shell heterostructures. The iron oxide shells are uniform, smooth, with characteristic porous structure, and their thickness can be readily tuned. The shell formation is highly dependent on the reaction parameters including pH and CTAB concentration. The Fe 2 O 3 shell is amorphous and exhibits nearly zero remanence and coercivity, while the Fe 3 O 4 shell is ferromagnetic with a low saturation magnetization of about 0.5 emu g -1 due to its low crystallinity and the porous structure. At elevated temperatures achieved by plasmonic heating of the Au core, the Fe 2 O 3 shell transforms from amorphous to γ-Fe 2 O 3 and α-Fe 2 O 3 phases, while the Fe 3 O 4 phase disappears because of the oxidation of Fe 2+ . A 1.4-fold increase of photocatalytic performance is observed due to the plasmonic resonance provided by the Au core. The photocatalytic efficiency of Fe 3 O 4 is about 1.7-fold higher than Fe 2 O 3 as more surface defects are present on the Fe 3 O 4 shell, promoting the adsorption and activation of reagents on the surface during the catalytic reactions. This approach can be readily extended to other nanostructures including Au spherical nanoparticles and nanostars. These highly uniform and multifunctional core-shell heterostructures can be of great potential in a variety of energy, magnetic, and environment applications.

Reducing the effects of X-ray pre-heat in double shell NIF capsules by over-coating the high Z shell

Science.gov (United States)

Wilson, Douglas; Milovich, J. L.; Daughton, W. S.; Loomis, E. N.; Sauppe, J. P.; Dodd, E. S.; Merritt, E. C.; Montgomery, D. S.; Renner, D. B.; Haines, B. M.; Cardenas, T.; Desjardins, T.; Palaniyappan, S.; Batha, S. H.

2017-10-01

Hohlraum generated X-rays will penetrate the ablator of a double shell capsule and be absorbed in the outer surface of the inner capsule. The ablative pressure this generates drives a shock into the central fuel, and a reflected shock that reaches the inner high-Z shell surface before the main shock even enters the fuel. With a beryllium over-coat preheat X-rays deposit just inside the beryllium/high z interface. The beryllium tamps the preheat expansion, eliminating ablation, and dramatically reducing pressure. The slow shock or pressure wave it generates is then overtaken by the main shock, avoiding an early shock in the fuel and increasing capsule yield.

Facile synthesis of nanorod-assembled multi-shelled Co3O4 hollow microspheres for high-performance supercapacitors

Science.gov (United States)

Wang, Yaping; Pan, Anqiang; Zhu, Qinyu; Nie, Zhiwei; Zhang, Yifang; Tang, Yan; Liang, Shuquan; Cao, Guozhong

2014-12-01

In this work, we report a novel strategy for the controlled synthesis of nanorod assembled multi-shelled cobalt oxide (Co3O4) hollow microspheres (HSs). The Co2CO3(OH)2 NRs are first vertically grown on the carbon microspheres (CS) to form the core-shelled composites by a low-temperature solution route. The multi-shelled hollow interiors within the Co3O4 microspheres are unconventionally obtained by annealing the as-prepared core-shell structured CS@Co2CO3(OH)2 composite in air. When evaluated for supercapacitive performance, the multi-shelled Co3O4 hollow microspheres exhibit high capacitance of 394.4 and 360 F g-1 at the current densities of 2 A g-1 and 10 A g-1, respectively. The superior electrochemical performance can be attributed to the multi-shelled hollow structures, which facilitate the electrolyte penetration and provide more active sites for the electrochemical reactions.

Observational evidence of competing source, loss, and transport processes for relativistic electrons in Earth's outer radiation belt

Science.gov (United States)

Turner, Drew; Mann, Ian; Usanova, Maria; Rodriguez, Juan; Henderson, Mike; Angelopoulos, Vassilis; Morley, Steven; Claudepierre, Seth; Li, Wen; Kellerman, Adam; Boyd, Alexander; Kim, Kyung-Chan

Earth’s outer electron radiation belt is a region of extreme variability, with relativistic electron intensities changing by orders of magnitude over time scales ranging from minutes to years. Extreme variations of outer belt electrons ultimately result from the relative impacts of various competing source (and acceleration), loss, and transport processes. Most of these processes involve wave-particle interactions between outer belt electrons and different types of plasma waves in the inner magnetosphere, and in turn, the activity of these waves depends on different solar wind and magnetospheric driving conditions and thus can vary drastically from event to event. Using multipoint analysis with data from NASA’s Van Allen Probes, THEMIS, and SAMPEX missions, NOAA’s GOES and POES constellations, and ground-based observatories, we present results from case studies revealing how different source/acceleration and loss mechanisms compete during active periods to result in drastically different distributions of outer belt electrons. By using a combination of low-Earth orbiting and high-altitude-equatorial orbiting satellites, we briefly review how it is possible to get a much more complete picture of certain wave activity and electron losses over the full range of MLTs and L-shells throughout the radiation belt. We then show example cases highlighting the importance of particular mechanisms, including: substorm injections and whistler-mode chorus waves for the source and acceleration of relativistic electrons; magnetopause shadowing and wave-particle interactions with EMIC waves for sudden losses; and ULF wave activity for driving radial transport, a process which is important for redistributing relativistic electrons, contributing both to acceleration and loss processes. We show how relativistic electron enhancement events involve local acceleration that is consistent with wave-particle interactions between a seed population of 10s to 100s of keV electrons, with a

ECO-TECHNIQUE OF SEWER RENOVATION USING COMPOSITE SHELLS: STRUCTURAL ANALYSIS

Directory of Open Access Journals (Sweden)

B. Attaf

2015-07-01

Full Text Available An eco-technical renovation of the sewage system is developed in this paper; this technique involves incorporating into the existing sewer a series of jointed prefabricated sandwich or composite shells. The purpose of his study is to determine the structural shell deflection, the high displacement areas and to validate the non-failure criterion for each ply constituting the inner and outer laminate facings. The numerical results were obtained at low cost by using the finite element method. Studies have focused on structural analysis of a typical shell unit with an ovoid form (egg-shaped section when it is subjected, during annular space filling operation, to pressure forces generated by wet concrete. To ensure the safety of the composite shell structure, Tsai-Hill criterion function is applied and results are presented for the most stressed plies

Modification of Ag shell on upconversion populating paths of NaYF4:Yb3+,Er3+@Ag nanocomposites

International Nuclear Information System (INIS)

Sun, Jiao; Liu, Haipeng; Wu, Di; Dong, Biao; Sun, Liankun

2013-01-01

NaYF 4 :Yb 3+ ,Er 3+ @Ag core–shell nanocomposites were prepared. Due to the outer shell of Ag, some modifications were found on the upconversion (UC) processes of NaYF 4 :Yb 3+ ,Er 3+ core nanoparticles (NPs) caused by the co-interaction of surface effect, surface plasma absorption effect and local thermal effect under infrared radiation. Upon 980 nm excitation, the relative UC intensity of the green ( 2 H 11/2 , 4 S 3/2 – 4 I 15/2 ) to red ( 4 F 9/2 – 4 I 15/2 ) and the slope of power-dependence increased intensively, and three-photon population process for the green level appeared. -- Highlights: ► NaYF 4 :Yb 3+ ,Er 3+ @Ag core/shell nanocomposites were fabricated. ► The coating of Ag outer shell leads to the increase of the green UCL. ► Three-photon population process for the green level appeared after Ag coating.

Efficient charge carriers induced by extra outer-shell electrons in iron-pnictides: a comparison between Ni- and Co-doped CaFeAsF

International Nuclear Information System (INIS)

Zhang Min; Yu Yi; Tan Shun; Zhang Yuheng; Zhang Changjin; Zhang Lei; Qu Zhe; Ling Langsheng; Xi, Chuanying

2010-01-01

A comprehensive study of the difference between CaFe 1-x Ni x AsF and CaFe 1-x Co x AsF systems has been carried out by measuring the efficient charge carrier concentration, the valence states and the superconducting phase diagram. It is found that at the same doping level, Ni doping introduces nearly twice the number of charge carriers as Co doping. However, x-ray absorption near-edge spectroscopy measurements reveal that the valence state of Fe in both systems is close to 2, indicating that there is no valence mismatch. We suggest that the charge carriers in CaFe 1-x M x AsF (M=transition metal elements) are not induced by valence mismatch but come from the difference in the number of outer-shell electrons. We also suggest that with Ni and Co doping, the systems change from a multi-band material in the underdoped regions to a single-band state in the overdoped regions.

Design, Performance, and Calibration of the CMS Hadron-Outer Calorimeter

CERN Document Server

Abdullin, Salavat; Acharya, Bannaje Sripathi; Adam, Nadia; Adams, Mark Raymond; Akchurin, Nural; Akgun, Ugur; Albayrak, Elif Asli; Anderson, E Walter; Antchev, Georgy; Arcidy, M; Ayan, S; Aydin, Sezgin; Aziz, Tariq; Baarmand, Marc M; Babich, Kanstantsin; Baden, Drew; Bakirci, Mustafa Numan; Banerjee, Sunanda; Banerjee, Sudeshna; Bard, Robert; Barnes, Virgil E; Bawa, Harinder Singh; Baiatian, G; Bencze, Gyorgy; Beri, Suman Bala; Berntzon, Lisa; Bhatnagar, Vipin; Bhatti, Anwar; Bodek, Arie; Bose, Suvadeep; Bose, Tulika; Budd, Howard; Burchesky, Kyle; Camporesi, Tiziano; Cankocak, Kerem; Carrell, Kenneth Wayne; Cerci, Salim; Chendvankar, Sanjay; Chung, Yeon Sei; Clarida, Warren; Cremaldi, Lucien Marcus; Cushman, Priscilla; Damgov, Jordan; De Barbaro, Pawel; Debbins, Paul; Deliomeroglu, Mehmet; Demianov, A; de Visser, Theo; Deshpande, Pandurang Vishnu; Díaz, Jonathan; Dimitrov, Lubomir; Dugad, Shashikant; Dumanoglu, Isa; Duru, Firdevs; Efthymiopoulos, I; Elias, John E; Elvira, D; Emeliantchik, Igor; Eno, Sarah Catherine; Ershov, Alexander; Erturk, Sefa; Esen, Selda; Eskut, Eda; Fenyvesi, Andras; Fisher, Wade Cameron; Freeman, Jim; Ganguli, Som N; Gaultney, Vanessa; Gamsizkan, Halil; Gavrilov, Vladimir; Genchev, Vladimir; Gleyzer, Sergei V; Golutvin, Igor; Goncharov, Petr; Grassi, Tullio; Green, Dan; Gribushin, Andrey; Grinev, B; Gurtu, Atul; Murat Güler, A; Gülmez, Erhan; Gümüs, K; Haelen, T; Hagopian, Sharon; Hagopian, Vasken; Halyo, Valerie; Hashemi, Majid; Hauptman, John M; Hazen, Eric; Heering, Arjan Hendrix; Heister, Arno; Hunt, Adam; Ilyina, N; Ingram, D; Isiksal, Engin; Jarvis, Chad; Jeong, Chiyoung; Johnson, Kurtis F; Jones, John; Kaftanov, Vitali; Kalagin, Vladimir; Kalinin, Alexey; Kalmani, Suresh Devendrappa; Karmgard, Daniel John; Kaur, Manjit; Kaya, Mithat; Kaya, Ozlem; Kayis-Topaksu, A; Kellogg, Richard G; Khmelnikov, Alexander; Kim, Heejong; Kisselevich, I; Kodolova, Olga; Kohli, Jatinder Mohan; Kolossov, V; Korablev, Andrey; Korneev, Yury; Kosarev, Ivan; Kramer, Laird; Krinitsyn, Alexander; Krishnaswamy, Marthi Ramaswamy; Krokhotin, Andrey; Kryshkin, V; Kuleshov, Sergey; Kumar, Arun; Kunori, Shuichi; Laasanen, Alvin T; Ladygin, Vladimir; Laird, Edward; Landsberg, Greg; Laszlo, Andras; Lawlor, C; Lazic, Dragoslav; Lee, Sang Joon; Levchuk, Leonid; Linn, Stephan; Litvintsev, Dmitri; Lobolo, L; Los, Serguei; Lubinsky, V; Lukanin, Vladimir; Ma, Yousi; Machado, Emanuel; Maity, Manas; Majumder, Gobinda; Mans, Jeremy; Marlow, Daniel; Markowitz, Pete; Martínez, German; Mazumdar, Kajari; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mescheryakov, G; Mestvirishvili, Alexi; Miller, Michael; Möller, A; Mohammadi-Najafabadi, M; Moissenz, P; Mondal, Naba Kumar; Mossolov, Vladimir; Nagaraj, P; Narasimham, Vemuri Syamala; Norbeck, Edwin; Olson, Jonathan; Onel, Yasar; Onengüt, G; Ozkan, Cigdem; Ozkurt, Halil; Ozkorucuklu, Suat; Ozok, Ferhat; Paktinat, S; Pal, Andras; Patil, Mandakini Ravindra; Penzo, Aldo; Petrushanko, Sergey; Petrosian, A; Pikalov, Vladimir; Piperov, Stefan; Podrasky, V; Polatoz, A; Pompos, Arnold; Popescu, Sorina; Posch, C; Pozdnyakov, Andrey; Qian, Weiming; Ralich, Robert; Reddy, L; Reidy, Jim; Rogalev, Evgueni; Roh, Youn; Rohlf, James; Ronzhin, Anatoly; Ruchti, Randy; Ryazanov, Anton; Safronov, Grigory; Sanders, David A; Sanzeni, Christopher; Sarycheva, Ludmila; Satyanarayana, B; Schmidt, Ianos; Sekmen, Sezen; Semenov, Sergey; Senchishin, V; Sergeyev, S; Serin, Meltem; Sever, Ramazan; Singh, B; Singh, Jas Bir; Sirunyan, Albert M; Skuja, Andris; Sharma, Seema; Sherwood, Brian; Shumeiko, Nikolai; Smirnov, Vitaly; Sogut, Kenan; Sonmez, Nasuf; Sorokin, Pavel; Spezziga, Mario; Stefanovich, R; Stolin, Viatcheslav; Sudhakar, Katta; Sulak, Lawrence; Suzuki, Ichiro; Talov, Vladimir; Teplov, Konstantin; Thomas, Ray; Tonwar, Suresh C; Topakli, Huseyin; Tully, Christopher; Turchanovich, L; Ulyanov, A; Vanini, A; Vankov, Ivan; Vardanyan, Irina; Varela, F; Vergili, Mehmet; Verma, Piyush; Vesztergombi, Gyorgy; Vidal, Richard; Vishnevskiy, Alexander; Vlassov, E; Vodopiyanov, Igor; Volobouev, Igor; Volkov, Alexey; Volodko, Anton; Wang, Lei; Werner, Jeremy Scott; Wetstein, Matthew; Winn, Dave; Wigmans, Richard; Whitmore, Juliana; Wu, Shouxiang; Yazgan, Efe; Yetkin, Taylan; Zálán, Peter; Zarubin, Anatoli; Zeyrek, Mehmet

2008-01-01

The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with an outer calorimeter to ensure high energy shower containment in the calorimeter. Fabrication, testing and calibration of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing $\\et$ measurements at LHC energies. The outer hadron calorimeter will also be used for the muon trigger in coincidence with other muon chambers in CMS.

Performance of an anisotropic Allman/DKT 3-node thin triangular flat shell element

Science.gov (United States)

Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

1992-05-01

A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular flat shell element in global coordinates is presented. An Allman triangle (AT) is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending element. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, the membrane and bending strain-displacement matrices. Using the aforementioned approach, the objective of this study is to develop and test the performance of a practical 3-node flat shell element that could be used in plate problems with unsymmetrically stacked composite laminates. The performance of the latter element is tested on plates of varying aspect ratios. The developed 3-node shell element should simplify the programming task and have the potential of reducing the computational time.

MicroShell Minimalist Shell for Xilinx Microprocessors

Science.gov (United States)

Werne, Thomas A.

2011-01-01

MicroShell is a lightweight shell environment for engineers and software developers working with embedded microprocessors in Xilinx FPGAs. (MicroShell has also been successfully ported to run on ARM Cortex-M1 microprocessors in Actel ProASIC3 FPGAs, but without project-integration support.) Micro Shell decreases the time spent performing initial tests of field-programmable gate array (FPGA) designs, simplifies running customizable one-time-only experiments, and provides a familiar-feeling command-line interface. The program comes with a collection of useful functions and enables the designer to add an unlimited number of custom commands, which are callable from the command-line. The commands are parameterizable (using the C-based command-line parameter idiom), so the designer can use one function to exercise hardware with different values. Also, since many hardware peripherals instantiated in FPGAs have reasonably simple register-mapped I/O interfaces, the engineer can edit and view hardware parameter settings at any time without stopping the processor. MicroShell comes with a set of support scripts that interface seamlessly with Xilinx's EDK tool. Adding an instance of MicroShell to a project is as simple as marking a check box in a library configuration dialog box and specifying a software project directory. The support scripts then examine the hardware design, build design-specific functions, conditionally include processor-specific functions, and complete the compilation process. For code-size constrained designs, most of the stock functionality can be excluded from the compiled library. When all of the configurable options are removed from the binary, MicroShell has an unoptimized memory footprint of about 4.8 kB and a size-optimized footprint of about 2.3 kB. Since MicroShell allows unfettered access to all processor-accessible memory locations, it is possible to perform live patching on a running system. This can be useful, for instance, if a bug is

Outer Sphere Adsorption of Pb(II)EDTA on Goethite

Energy Technology Data Exchange (ETDEWEB)

Bargar, John R

1999-07-16

FTIR and EXAFS spectroscopic measurements were performed on Pb(II)EDTA adsorbed on goethite as functions of pH (4-6), Pb(II)EDTA concentration (0.11 {micro}M - 72 {micro}M), and ionic strength (16 {micro}M - 0.5M). FTIR measurements show no evidence for carboxylate-Fe(III) bonding or protonation of EDTA at Pb:EDTA = 1:1. Both FTIR and EXAFS measurements suggest that EDTA acts as a hexadentate ligand, with all four of its carboxylate and both amine groups bonded to Pb(II). No evidence was observed for inner-sphere Pb(II)-goethite bonding at Pb:EDTA = 1:1. Hence, the adsorbed complexes should have composition Pb(II)EDTA{sup 2{minus}}. Since substantial uptake of PbEDTA(II){sup 2{minus}} occurred in the samples, we infer that Pb(II)EDTA{sup 2{minus}} adsorbed as outer-sphere complexes and/or as complexes that lose part of their solvation shells and hydrogen bond directly to goethite surface sites. We propose the term ''hydration-sphere'' for the latter type of complexes because they should occupy space in the primary hydration spheres of goethite surface functional groups, and to distinguish this mode of sorption from common structural definitions of inner- and outer-sphere complexes. The similarity of Pb(II) uptake isotherms to those of other divalent metal ions complexed by EDTA suggests that they too adsorb by these mechanisms. The lack of evidence for inner-sphere EDTA-Fe(III) bonding suggests that previously proposed metal-ligand - promoted dissolution mechanisms should be modified, specifically to account for the presence of outer-sphere precursor species.

Outer atmospheric research

International Nuclear Information System (INIS)

Anderson, J.L.

1988-01-01

The region above the earth from about 90 km to 150 km is a major part of the upper or outer atmosphere. It is relatively unexplored, being too high for balloons or aircraft and too low for persistent orbiting spacecraft. However, the concept of a tethered subsatellite, deployed downward from an orbiting, more massive craft such as the Space Shuttle, opens the possibility of a research capability that could provide global mapping of this region. The need for research in this thick spherical shell above the earth falls into two major categories: (1) scientific data for understanding and modeling the global atmosphere and thereby determining its role in the earth system, and (2) engineering data for the design of future aerospace vehicles that will operate there. This paper presents an overview and synthesis of the currently perceived research needs and the state-of-the-art of the proposed tethered research capability. 16 references

The Impact of Ceramic Shell Strength on Hot Tearing during Investment Casting

International Nuclear Information System (INIS)

Norouzi, Saeid; Farhangi, Hassan

2011-01-01

The effect of ceramic shell strength on hot tearing susceptibility during solidification was inspected practicing investment casting of the cobalt-base superalloy samples with the same casting conditions, but different ceramic shell systems. Results showed that the lower the ceramic shell strength upon using polymer additives, the lower the hindered contraction rate, and the lower the hindered contraction rate, the smaller the hot tearing tendency. Optical microscopy and electron microscopy scanning revealed that the hot tear propagated along the last solidified interdendritic phase, and that the hot tear surface had two major modes: 1) the ductile region in the outer layer; and 2) the inner region of liquid embrittlement.

Study the Effect of the Flow on the Performance of a shell and Tube Type Heat Exchanger using Experimental Design Technique

Directory of Open Access Journals (Sweden)

Zuher Hassan Abdullah

2016-10-01

Full Text Available In the current research an experimental study was done to show the effect of pulse flow on the effectiveness of shell and tube type heat exchanger. the study was in the case of steady and pulse flows with a changing mass flow rate of hot water flowing inside the pipes of the heat exchanger for the range between (0.0273-0.0819 kg / s  at fix mass flow rate of cold water that flows through the shell and on the outer surface of the pipes when (0.0416 kg / s, to obtain pulsing a used was solenoid valve. The research aims to measure the percentage effect of independent factors which were presenting the mass flow rate of hot water, flow type and the surrounding environment conditions of the experimental side upon shell and tube type heat exchanger performance using experimental design technique at the significant level (0.05.The results derived from the experimental tests showed that pulse flow leads to increase internal heat transfer coefficient (hi comparing with its value in the steady flow and the highest increase was by (9.75% at a mass flow rate of hot water (0.0416 kg / s and increases the overall heat transfer coefficient (U, where the highest percentage was by 4.68% at a mass flow rate of hot water (0.0416kg/s. The results also showed increasing both the number of transmitted units (NTU and the effectiveness of the shell and tube type heat exchanger ( in the case of pulse flow of its value in the steady flow and the highest percentage of increase occurring was (4.75% and (1.85%, respectively, and at the mass flow rate of hot water (0.0416 kg / s. Percentage effect of mass flow rate of hot water was (97%, 97.42%, 95.5%, 99.48% and the percentage effect of each flow type and the errors were (2.8%, 2.25%, 2.44%, 0.4% and (0. 2, 0.33%, 2.06%, 0.12 respectively

High-resolution TEM characterization of ZnO core-shell nanowires for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Divitini, G; Ducati, C [Department of Materials Science, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Plank, N O V; Welland, M E [Nanoscience Centre, Department of Engineering, University of Cambridge, CB3 0FF (United Kingdom); Snaith, H J, E-mail: gd322@cam.ac.u [Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU (United Kingdom)

2010-07-01

Recently ZnO nanowire films have been used in very promising and inexpensive dye-sensitized solar cells (DSSC). It was found that the performance of the devices can be enhanced by functionalising the nanowires with a thin metal oxide coating. This nm-scale shell is believed to tailor the electronic structure of the nanowire, and help the absorption of the dye. Core-shell ZnO nanowire structures are synthesised at low temperature (below 120{sup 0}C) by consecutive hydrothermal growth steps. Different materials are investigated for the coating, including Mg, Al, Cs and Zr oxides. High resolution TEM is used to characterise the quality of both the nanowire core and the shell, and to monitor the thickness and the degree of crystallisation of the oxide coating. The interface between the nanowire core and the outer shell is investigated in order to understand the adhesion of the coating, and give valuable feedback for the synthesis process. Nanowire films are packaged into dye-sensitised solar cell prototypes; samples coated with ZrO{sub 2} and MgO show the largest enhancement in the photocurrent and open-circuit voltage and look very promising for further improvement.

Analysis Bounding Double Shell Tank (DST) Performance for the Hanford Tank Waste Operation Simulator Case 2

International Nuclear Information System (INIS)

SMITH, D.F.

2002-01-01

The purpose of this analysis is to compare the latest Tank Farm Contractor Operation and Utilization Plan (HNF-SD-WM-SP-012, Rev. 3) ''Case 2'' operating scenarios with a previous bounding analysis for the Double-Shell Tank (DST) System in order to provide a technical assessment against the current set of DST System performance requirements. A later update to HNF-SD-WM-SP-012 (i.e., Rev. 3A), released in late December 2001, did not impact the results of this analysis. This analysis provides technical support for revising the Performance Requirements for the Double-Shell Tank System, HNF-2168, Rev. 3, used as the basis for defining performance requirements noted in System Specification for the Double-Shell Tank System, HNF-SD-WM-TRD-007. Rev. 1

Design and analysis of reactor containment of steel-concrete composite laminated shell

International Nuclear Information System (INIS)

Ichikawa, K.; Isobata, O.; Kawamata, S.

1977-01-01

A new scheme of containment consisting of steel-concrete laminated shell is being developed. In the main part of a cylindrical vessel, the shell consists of two layers of thin steel plates located at the inner and outer surfaces, and a layer of concrete core into which both the steel plates are anchored. Because of the compressive and shearing resistance of the concrete core, the layers behave as a composite solid shell. Membrane forces are shared by steel plates and partly by concrete core. Bending moment is effectively resisted by the section with extreme layers of steel. Therefore, both surfaces can be designed as extremely thin plates: the inner plate, which is a load carrying members as well as a liner, can be welded without the laborious process of stress-relieving, and various jointing methods can be applied to the outer plate which is free from the need for leak tightness. The capability of the composite layers of behaving as a unified solid shell section depends largely on the shearing rigidity of the concrete core. However, as its resisting capacity to transverse shearing force is comparatively low, a device for reducing the shearing stress at the junction to the base mat is needed. In the new scheme, this part of the cylindrical shell is divided into multiple layers of the same kind of composite shell. This device makes the stiffness of the bottom of the cylindrical shell to lateral movement minimum while maintaining the proper resistance to membrane forces. The analysis shows that the transverse shearing stress can be reduced to less than 1√n of the ordinary case by dividing the thickness of the shell into n layers which are able to slip against each other at the contact surface. In order to validate the feasibility and safety of this new design, the results of analysis on the basis of up-to-date design loads are presented

L-shell bifurcation of electron outer belt at the recovery phase of geomagnetic storm as observed by STEP-F and SphinX instruments onboard the CORONAS-Photon satellite

Science.gov (United States)

Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw; Podgorski, Piotr

2016-07-01

Radiation belts and sporadically arising volumes comprising enhanced charged particle fluxes in the Earth's magnetosphere are typically studied by space-borne telescopes, semiconductor, scintillation, gaseous and other types of detectors. Ambient and internal electron bremsstrahlung in hard X-ray arises as a result of interaction of precipitating particles with the atmosphere (balloon experiments) and with the satellite's housings and instrument boxes (orbital experiments). Theses emissions provide a number of new information on the physics of radiation belts. The energies of primary electrons and their spectra responsible for measured X-ray emissions remain usually unknown. Combined measurements of particle fluxes, and their bremsstrahlung by individual satellite instruments placed next to each other provide insight to respective processes. The satellite telescope of electrons and protons STEP-F and the solar X-ray spectrophotometer SphinX were placed in close proximity to each other aboard CORONAS-Photon, the low, circular and highly inclined orbit satellite. Based on joint analysis of the data we detected new features in the high energy particle distributions of the Earth's magnetosphere during deep minimum of solar activity [1-3]. In this research the bifurcation of Van Allen outer electron radiation belt during the weak geomagnetic storm and during passage of interplanetary shock are discussed. Outer belt bifurcation and growth of electron fluxes in a wide energy range were recorded by both instruments during the recovery phase of May 8, 2009 substorm. STEP-F recorded also barely perceptible outer belt splitting on August 5, 2009, after arrival of interplanetary shock to the Earth's magnetosphere bowshock. The STEP-F and SphinX data are compared with the space weather indexes, and with relativistic electron fluxes observed at geostationary orbit. We discuss possible mechanism of the phenomena consisting in the splitting of drift shells because of Earth

A general and high-yield galvanic displacement approach to Au-M (M = Au, Pd, and Pt) core-shell nanostructures with porous shells and enhanced electrocatalytic performances.

Science.gov (United States)

Kuai, Long; Geng, Baoyou; Wang, Shaozhen; Sang, Yan

2012-07-23

In this work, we utilize the galvanic displacement synthesis and make it a general and efficient method for the preparation of Au-M (M = Au, Pd, and Pt) core-shell nanostructures with porous shells, which consist of multilayer nanoparticles. The method is generally applicable to the preparation of Au-Au, Au-Pd, and Au-Pt core-shell nanostructures with typical porous shells. Moreover, the Au-Au isomeric core-shell nanostructure is reported for the first time. The lower oxidation states of Au(I), Pd(II), and Pt(II) are supposed to contribute to the formation of porous core-shell nanostructures instead of yolk-shell nanostructures. The electrocatalytic ethanol oxidation and oxygen reduction reaction (ORR) performance of porous Au-Pd core-shell nanostructures are assessed as a typical example for the investigation of the advantages of the obtained core-shell nanostructures. As expected, the Au-Pd core-shell nanostructure indeed exhibits a significantly reduced overpotential (the peak potential is shifted in the positive direction by 44 mV and 32 mV), a much improved CO tolerance (I(f)/I(b) is 3.6 and 1.63 times higher), and an enhanced catalytic stability in comparison with Pd nanoparticles and Pt/C catalysts. Thus, porous Au-M (M = Au, Pd, and Pt) core-shell nanostructures may provide many opportunities in the fields of organic catalysis, direct alcohol fuel cells, surface-enhanced Raman scattering, and so forth. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diagnostic method for measuring plasma-induced voltages on the PBX-M [Princeton Beta Experiment-Modified] stabilizing shell

International Nuclear Information System (INIS)

Kugel, H.W.; Okabayashi, M.; Schweitzer, S.

1990-07-01

The Princeton Beta Experiment-Modified (PBX-M) has a close-fitting conducting, passive plate, stabilizing shell which nearly surrounds highly indented, bean-shaped plasmas. The proximity of this electrically isolated shell to a large fraction of the plasma surface allows measurements similar to previous work on other tokamaks using floating probes and limiters. Measurements were performed to characterize the plasma-induced voltages on the PBX-M passive plate stabilizing shell during high-β plasmas. Voltage differences were measured between the respective passive plate toroidal and poloidal gaps, the respective passive plates and the vessel, and an outer poloidal graphite limiter and its passive plate. The calibration and qualification testing procedures are discussed. The initial measurements found that the largest voltages were observed at plasma start-up and at the plasma current disruption and exhibited characteristics depending on operating conditions. The highest voltages observed have been at disruption and were less than 2 kV. 9 refs., 5 figs

Three-dimensional core-shell Fe_2O_3 @ carbon/carbon cloth as binder-free anode for the high-performance lithium-ion batteries

International Nuclear Information System (INIS)

Wang, Xiaohua; Zhang, Miao; Liu, Enzuo; He, Fang; Shi, Chunsheng; He, Chunnian; Li, Jiajun; Zhao, Naiqin

2016-01-01

Highlights: • The 3D core-shell Fe_2O_3@C/CC structure is fabricated by simple hydrothermal route. • The composite connected 3D carbon networks consist of carbon cloth, Fe_2O_3 nanorods and outer carbon layer. • The Fe_2O_3@C/CC used as binder-free anode in LIBs, demonstrates excellent performances. - Abstract: A facile and scalable strategy is developed to fabricate three dimensional core-shell Fe_2O_3 @ carbon/carbon cloth structure by simple hydrothermal route as binder-free lithium-ion battery anode. In the unique structure, carbon coated Fe_2O_3 nanorods uniformly disperse on carbon cloth which forms the conductive carbon network. The hierarchical porous Fe_2O_3 nanorods in situ grown on the carbon cloth can effectively shorten the transfer paths of lithium ions and reduce the contact resistance. The carbon coating significantly inhibits pulverization of active materials during the repeated Li-ion insertion/extraction, as well as the direct exposure of Fe_2O_3 to the electrolyte. Benefiting from the structural integrity and flexibility, the nanocomposites used as binder-free anode for lithium-ion batteries, demonstrate high reversible capacity and excellent cyclability. Moreover, this kind of material represents an alternative promising candidate for flexible, cost-effective, and binder-free energy storage devices.

A new Predictive Model for Relativistic Electrons in Outer Radiation Belt

Science.gov (United States)

Chen, Y.

2017-12-01

Relativistic electrons trapped in the Earth's outer radiation belt present a highly hazardous radiation environment for spaceborne electronics. These energetic electrons, with kinetic energies up to several megaelectron-volt (MeV), manifest a highly dynamic and event-specific nature due to the delicate interplay of competing transport, acceleration and loss processes. Therefore, developing a forecasting capability for outer belt MeV electrons has long been a critical and challenging task for the space weather community. Recently, the vital roles of electron resonance with waves (including such as chorus and electromagnetic ion cyclotron) have been widely recognized; however, it is still difficult for current diffusion radiation belt models to reproduce the behavior of MeV electrons during individual geomagnetic storms, mainly because of the large uncertainties existing in input parameters. In this work, we expanded our previous cross-energy cross-pitch-angle coherence study and developed a new predictive model for MeV electrons over a wide range of L-shells inside the outer radiation belt. This new model uses NOAA POES observations from low-Earth-orbits (LEOs) as inputs to provide high-fidelity nowcast (multiple hour prediction) and forecast (> 1 day prediction) of the energization of MeV electrons as well as the evolving MeV electron distributions afterwards during storms. Performance of the predictive model is quantified by long-term in situ data from Van Allen Probes and LANL GEO satellites. This study adds new science significance to an existing LEO space infrastructure, and provides reliable and powerful tools to the whole space community.

L-shell dielectronic recombination for 0-like ions

International Nuclear Information System (INIS)

Omar, G.; Semedal, R.; Shahin, F.; El-Sherbini, T.H.

2007-01-01

In electron-Ion (e/I) collisions, a free electron may be captured by a positively charged ion having bound electrons with a simultaneous, excitation. This radiationless capture, most probably, creates resonance (d) states. These d- states may stabilize by emission of radiation (x-rays). This two-step process is known as Dielectronic recombination (D R). At high incident-electron energy, D R dominates over the radiative recombination (R R) and three- body recombination (Tbr) processes. Thus, D R is one of the most effective recombination for ionisation balance in solar corona and artificial plasma . In addition, the D R rates are needed for the development of nuclear fusion plasma. Thus, D R is still an interesting process m both experimental and theoretical research. Previously we have done the D R rates for 0-like AL 5+ , Cl 9+ Ti 14+ and Zn 22+ ions with K-shell excitation. In this work, the D R rates are calculated for the same ions, but with L-shell excitation. It is found that, the peak values of the D R rates for L-shell excitation are 1000 times larger than that for K-shell excitation. This means that, D R process is the most efficient mechanism for outer-shell excitations. It is found also that, the Dr rates for L-shell excitation peak at Kt = 6 Ry, 22 Ry for AL 5+ and Ti 14+ ions respectively. These Kt values are much smaller than that for for K-shell excitation

Double-shell target designs for the Los Alamos Scientific Laboratory eight-beam laser system

International Nuclear Information System (INIS)

Kindel, J.M.; Stroscio, M.A.

1978-03-01

We investigate two double-pusher laser fusion targets, one that incorporates an outer exploding pusher shell and another that uses velocity multiplication. Specific designs are presented for the Los Alamos Scientific Laboratory Eight-Beam Laser System

Vacuum Outer-Gap Structure in Pulsar Outer Magnetospheres

International Nuclear Information System (INIS)

Gui-Fang, Lin; Li, Zhang

2009-01-01

We study the vacuum outer-gap structure in the outer magnetosphere of rotation-powered pulsars by considering the limit of trans-field height through a pair production process. In this case, the trans-field height is limited by the photon-photon pair production process and the outer boundary of the outer gap can be extended outside the light cylinder. By solving self-consistently the Poisson equation for electrical potential and the Boltzmann equations of electrons/positrons and γ-rays in a vacuum outer gap for the parameters of Vela pulsar, we obtain an approximate geometry of the outer gap, i.e. the trans-field height is limited by the pair-production process and increases with the radial distance to the star and the width of the outer gap starts at the inner boundary (near the null charge surface) and ends at the outer boundary which locates inside or outside the light cylinder depending on the inclination angle. (geophysics, astronomy, and astrophysics)

Polydopamine and MnO2 core-shell composites for high-performance supercapacitors

Science.gov (United States)

Hou, Ding; Tao, Haisheng; Zhu, Xuezhen; Li, Maoguo

2017-10-01

Polydopamine and MnO2 core-shell composites (PDA@MnO2) for high-performance supercapacitors had been successfully synthesized by a facile and fast method. The morphology, crystalline phase and chemical composition of PDA@MnO2 composites are characterized using SEM, TEM, XRD, EDS and XPS. The performance of PDA@MnO2 composites are further investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy in 1 M Na2SO4 electrolyte. The PDA@MnO2 core-shell nanostructure composites exhibit a high capacitance of 193 F g-1 at the current density of 1A g-1 and retained over 81.2% of its initial capacitance after 2500 cycles of charge-discharge at 2 A g-1. The results manifest that the PDA@MnO2 composites can be potentially applied in supercapacitors.

Silver-nickel oxide core-shell nanoparticle array electrode with enhanced lithium-storage performance

International Nuclear Information System (INIS)

Zhao, Wenjia; Du, Ning; Zhang, Hui; Yang, Deren

2015-01-01

We demonstrate the synthesis of Ag-NiO core-shell nanoparticle arrays via a one-step solution-immersion process and subsequent RF-sputtering technique. The Ag nanoparticle arrays on copper substrate are firstly prepared by a displacement reaction at mild temperature of 303K. Then, a NiO layer is deposited onto the surface of the Ag nanoparticles via RF-sputtering technique. When evaluated as an anode for lithium-ion batteries, the Ag-NiO core-shell electrode shows higher capacity and better cycling performance than the planar NiO electrode. The in-situ synthesized Ag nanoparticles can enhance the interfacial strength between the active material and substrate, andimprove the electrical conductivity of the electrode, which may be responsible for the enhanced performance

Dispersion properties of three-layered orthotropic shells

International Nuclear Information System (INIS)

Markus, S.

1995-01-01

This paper studies the harmonic wave propagation in thick, cylindrical, three-layered shells of infinite length. Both the outer layers and the core are composites made of short strand fiberglass and polyester resin. The randomly oriented fibers were approximately in parallel planes to constitute a transversely isotropic fibre composite. The planes of isotropy in the outer layers are orthogonal to the plane of isotropy at the core. A closed form solution of the exact linear equations of elasticity in sought in terms of a Frobenius series. The influence of the core thickness on the dynamics of the wave motion is estimated from numerically computed dispersion curves. Asymmetric wave motion is given prime consideration and the different types of waves which can occur are identified over a wide range of wave numbers

Performance model of metallic concentric tube recuperator with counter flow arrangement

Energy Technology Data Exchange (ETDEWEB)

Sharma, Harshdeep [HIET, Department of Mechanical Engineering, Ghaziabad, Uttar Pradesh (India); Kumar, Anoop; Goel, Varun [NIT, Department of Mechanical Engineering, Hamirpur, Himachal Pradesh (India)

2010-03-15

A performance model for counter flow arrangement in concentric tube recuperator that can be used to utilize the waste heat in the temperature range of 900-1,400 C is presented. The arrangement consists of metallic tubular inner and outer concentric shell with a small annular gap between two concentric shells. Flue gases pass through the inner shell while air passes through the annular gap in the reverse direction (counter flow arrangement). The height of the recuperator is divided into elements and an energy balance is performed on each elemental height. Results give necessary information about surface, gas and air temperature distribution, and the influence of operating conditions on recuperator performance. The recuperative effectiveness is found to be increased with increasing inlet gas temperature and decreased with increasing fuel flow rate. The present model accounts for all heat transfer processes pertinent to a counterflow radiation recuperator and provide a valuable tool for performance considerations. (orig.)

Influence of the shell thickness and charge distribution on the effective interaction between two like-charged hollow spheres.

Science.gov (United States)

Angelescu, Daniel G; Caragheorgheopol, Dan

2015-10-14

The mean-force and the potential of the mean force between two like-charged spherical shells were investigated in the salt-free limit using the primitive model and Monte Carlo simulations. Apart from an angular homogeneous distribution, a discrete charge distribution where point charges localized on the shell outer surface followed an icosahedral arrangement was considered. The electrostatic coupling of the model system was altered by the presence of mono-, trivalent counterions or small dendrimers, each one bearing a net charge of 9 e. We analyzed in detail how the shell thickness and the radial and angular distribution of the shell charges influenced the effective interaction between the shells. We found a sequence of the potential of the mean force similar to the like-charged filled spheres, ranging from long-range purely repulsive to short-range purely attractive as the electrostatic coupling increased. Both types of potentials were attenuated and an attractive-to-repulsive transition occurred in the presence of trivalent counterions as a result of (i) thinning the shell or (ii) shifting the shell charge from the outer towards the inner surface. The potential of the mean force became more attractive with the icosahedrally symmetric charge model, and additionally, at least one shell tended to line up with 5-fold symmetry axis along the longest axis of the simulation box at the maximum attraction. The results provided a basic framework of understanding the non-specific electrostatic origin of the agglomeration and long-range assembly of the viral nanoparticles.

Modeling the Electrostatics of Hollow Shell Suspensions: Ion Distribution, Pair Interactions, and Many-Body Effects.

Science.gov (United States)

Hallez, Yannick; Meireles, Martine

2016-10-11

Electrostatic interactions play a key role in hollow shell suspensions as they determine their structure, stability, thermodynamics, and rheology and also the loading capacity of small charged species for nanoreservoir applications. In this work, fast, reliable modeling strategies aimed at predicting the electrostatics of hollow shells for one, two, and many colloids are proposed and validated. The electrostatic potential inside and outside a hollow shell with a finite thickness and a specific permittivity is determined analytically in the Debye-Hückel (DH) limit. An expression for the interaction potential between two such hollow shells is then derived and validated numerically. It follows a classical Yukawa form with an effective charge depending on the shell geometry, permittivity, and inner and outer surface charge densities. The predictions of the Ornstein-Zernike (OZ) equation with this pair potential to determine equations of state are then evaluated by comparison to results obtained with a Brownian dynamics algorithm coupled to the resolution of the linearized Poisson-Boltzmann and Laplace equations (PB-BD simulations). The OZ equation based on the DLVO-like potential performs very well in the dilute regime as expected, but also quite well, and more surprisingly, in the concentrated regime in which full spheres exhibit significant many-body effects. These effects are shown to vanish for shells with small thickness and high permittivity. For highly charged hollow shells, we propose and validate a charge renormalization procedure. Finally, using PB-BD simulations, we show that the cell model predicts the ion distribution inside and outside hollow shells accurately in both electrostatically dilute and concentrated suspensions. We then determine the shell loading capacity as a function of salt concentration, volume fraction, and surface charge density for nanoreservoir applications such as drug delivery, sensing, or smart coatings.

Ageing and Performance Studies of the Outer Tracker of the LHCb Detector

International Nuclear Information System (INIS)

Haas, T.

2007-01-01

The Outer Tracker is part of the LHCb tracking system. It uses drift chamber to measure the track of a particle. The straws have a length of 2.5m and a diameter of 4.9 mm. They are operated in proportional mode and should measure tracks with a precision of 200 μm per hit. In the first part, this thesis presents the results of a performance study for the Outer Tracker, focussing on spatial resolution and efficiency. The main part of this thesis deals with aging studies. Neither a test with 8 keV X-rays nor with highly ionising protons showed any change in the module behavior due to aging. The acceleration factors compared to LHCb were 8-180 (anode current >80 nA/cm) in the most irradiated areas. A charge of up to 3 C/cm was accumulated. Aging tests at anode currents below 15 nA/cm (acceleration factor 1) showed a significant gain drop for the already produced modules after only a few days (1-2 mC/cm) of irradiation. The aging depends on several parameters like gas flow velocity or gas mixture. There is no aging for anode currents >12 nA/cm. This aging is an effect of outgassing material used in the module. Tests showed that the outgassing is probably caused by the epoxy adhesive. Flushing and warming the modules reduce the aging significantly. As things are, the Outer Tracker modules can be operated in LHCb for several years. (orig.)

Dynamic reponse of a cylindrical shell immersed in a potential fluid

International Nuclear Information System (INIS)

Cummings, G.E.

1978-01-01

A numerical solution technique is presented for determining the dynamic response of a thin, elastic, circular, cylindrical shell of constant wall thickness and density, immersed in a potential fluid. The shell may be excited by an arbitrary radial forcing function with a specified time history and spatial distribution. In addition, a pressure history may be specified over a segment of the fluid outer boundary. Any of the natural shell end conditions may be prescribed. A numerical instability prevented direct solutions where the ratio of the hydrodynamic forces to shell inertial forces is greater than two. This instability is believed to be the result of the weak coupling between the equations describing the fluid to those describing the shell. To circumvent this instability, an effective mass was calculated and added to the shell. Comparison of numerical to experimental results are made using a 1 / 12 scale model of a nuclear reactor core support barrel. Natural frequencies and modes are determined for this model in air, water, and oil. The computed frequencies compare to experimental results to within 15%. The use of this numerical technique is illustrated by comparing it to an analytical solution for shell beam modes and an uncertainty in the analytical technique concerning the proper effective mass to use, is resolved

Dynamic reponse of a cylindrical shell immersed in a potential fluid

Energy Technology Data Exchange (ETDEWEB)

Cummings, G.E.

1978-04-18

A numerical solution technique is presented for determining the dynamic response of a thin, elastic, circular, cylindrical shell of constant wall thickness and density, immersed in a potential fluid. The shell may be excited by an arbitrary radial forcing function with a specified time history and spatial distribution. In addition, a pressure history may be specified over a segment of the fluid outer boundary. Any of the natural shell end conditions may be prescribed. A numerical instability prevented direct solutions where the ratio of the hydrodynamic forces to shell inertial forces is greater than two. This instability is believed to be the result of the weak coupling between the equations describing the fluid to those describing the shell. To circumvent this instability, an effective mass was calculated and added to the shell. Comparison of numerical to experimental results are made using a /sup 1///sub 12/ scale model of a nuclear reactor core support barrel. Natural frequencies and modes are determined for this model in air, water, and oil. The computed frequencies compare to experimental results to within 15%. The use of this numerical technique is illustrated by comparing it to an analytical solution for shell beam modes and an uncertainty in the analytical technique concerning the proper effective mass to use, is resolved.

Study of the effect of varying core diameter, shell thickness and strain velocity on the tensile properties of single crystals of Cu-Ag core-shell nanowire using molecular dynamics simulations

Science.gov (United States)

Sarkar, Jit; Das, D. K.

2018-01-01

Core-shell type nanostructures show exceptional properties due to their unique structure having a central solid core of one type and an outer thin shell of another type which draw immense attention among researchers. In this study, molecular dynamics simulations are carried out on single crystals of copper-silver core-shell nanowires having wire diameter ranging from 9 to 30 nm with varying core diameter, shell thickness, and strain velocity. The tensile properties like yield strength, ultimate tensile strength, and Young's modulus are studied and correlated by varying one parameter at a time and keeping the other two parameters constant. The results obtained for a fixed wire size and different strain velocities were extrapolated to calculate the tensile properties like yield strength and Young's modulus at standard strain rate of 1 mm/min. The results show ultra-high tensile properties of copper-silver core-shell nanowires, several times than that of bulk copper and silver. These copper-silver core-shell nanowires can be used as a reinforcing agent in bulk metal matrix for developing ultra-high strength nanocomposites.

Hydrogen and helium shell burning during white dwarf accretion

Science.gov (United States)

Cui, Xiao; Meng, Xiang-Cun; Han, Zhan-Wen

2018-05-01

Type Ia supernovae (SNe Ia) are believed to be thermonuclear explosions of carbon oxygen (CO) white dwarfs (WDs) with masses close to the Chandrasekhar mass limit. How a CO WD accretes matter and grows in mass to this limit is not well understood, hindering our understanding of SN Ia explosions and the reliability of using SNe Ia as a cosmological distance indicator. In this work, we employed the stellar evolution code MESA to simulate the accretion process of hydrogen-rich material onto a 1.0 M ⊙ CO WD at a high rate (over the Eddington limit) of 4.3 × 10‑7 M ⊙ yr‑1. The simulation demonstrates the characteristics of the double shell burning on top of the WD, with a hydrogen shell burning on top of a helium burning shell. The results show that helium shell burning is not steady (i.e. it flashes). Flashes from the helium shell are weaker than those in the case of accretion of helium-rich material onto a CO WD. The carbon to oxygen mass ratio resulting from the helium shell burning is higher than what was previously thought. Interestingly, the CO WD growing due to accretion has an outer part containing a small fraction of helium in addition to carbon and oxygen. The flashes become weaker and weaker as the accretion continues.

Double-shell tank integrity assessments ultrasonic test equipment performance test

Energy Technology Data Exchange (ETDEWEB)

Pfluger, D.C.

1996-09-26

A double-shell tank (DST) inspection (DSTI) system was performance tested over three months until August 1995 at Pittsburgh, Pennsylvania, completing a contract initiated in February 1993 to design, fabricate, and test an ultrasonic inspection system intended to provide ultrasonic test (UT) and visual data to determine the integrity of 28 DSTs at Hanford. The DSTs are approximately one-million-gallon underground radioactive-waste storage tanks. The test was performed in accordance with a procedure (Jensen 1995) that included requirements described in the contract specification (Pfluger 1995). This report documents the results of tests conducted to evaluate the performance of the DSTI system against the requirements of the contract specification. The test of the DSTI system also reflects the performance of qualified personnel and operating procedures.

Mo-doped V2O5 hierarchical nanorod/nanoparticle core/shell porous microspheres with improved performance for cathode of lithium-ion battery

Science.gov (United States)

Yu, Haolin; Zeng, Jianyun; Hao, Wen; Zhou, Peng; Wen, Xiaogang

2018-05-01

Mo-doped V2O5 hierarchical nanorod/nanoparticle core/shell porous microspheres (MVHPMs) were prepared via a simple hydrothermal approach using ammonium metavanadate and ammonium molybdate as precursors followed by a thermal annealing process. The samples were characterized by XRD, SEM, TEM, EDS, and XPS carefully; it confirmed that porous microspheres with uniform Mo doping in the V2O5 matrix were obtained, and it contains an inner core self-assembled with 1D nanorods and outer shell consisting of nanoparticles. A plausible growth mechanism of Mo-doped V2O5 (Mo-V2O5) porous microspheres is suggested. The unique microstructure made the Mo-V2O5 hierarchical microspheres a good cathode material for Li-ion battery. The results indicate the synthesized Mo-V2O5 hierarchical microspheres exhibit well-improved electrochemical performance compared to the undoped samples. It delivers a high initial reversible capacity of 282 mAh g-1 at 0.2 C, 208 mAh g-1 at 2 C, and 111 mAh g-1 at 10 C, and it also exhibits good cycling stabilities; a capacity of 144 mAh g-1 is obtained after 200 cycles at 6 C with a capacity retention of > 82%, which is much high than that of pure V2O5 (95 mAh g-1 with a capacity retention of 72%). [Figure not available: see fulltext.

Electrochemical performance and structure evolution of core-shell nano-ring α-Fe_2O_3@Carbon anodes for lithium-ion batteries

International Nuclear Information System (INIS)

Sun, Yan-Hui; Liu, Shan; Zhou, Feng-Chen; Nan, Jun-Min

2016-01-01

Core-shell nano-ring α-Fe_2O_3@Carbon (CSNR) composites with different carbon content (CSNR-5%C and CSNR-13%C) are synthesized using a hydrothermal method by controlling different amounts of glucose and α-Fe_2O_3 nano-rings with further annealing. The CSNR electrodes exhibit much improved specific capacity, cycling stability and rate capability compared with that of bare nano-ring α-Fe_2O_3 (BNR), which is attributed to the core-shell nano-ring structure of CSNR. The carbon shell in the inner and outer surface of CSNR composite can increase electron conductivity of the electrode and inhibit the volume change of α-Fe_2O_3 during discharge/charge processes, and the nano-ring structure of CSNR can buffer the volume change too. The CSNR-5%C electrode shows super high initial discharge/charge capacities of 1570/1220 mAh g"−"1 and retains 920/897 mAh g"−"1 after 200 cycles at 500 mA g"−"1 (0.5C). Even at 2000 mA g"−"1 (2C), the electrode delivers the initial capacities of 1400/900 mAh g"−"1, and still maintains 630/610 mAh g"−"1 after 200 cycles. The core-shell nano-rings opened during cycling and rebuilt a new flower-like structure consisting of α-Fe_2O_3@Carbon nano-sheets. The space among the nano-sheet networks can further buffer the volume expansion of α-Fe_2O_3 and facilitate the transportation of electrons and Li"+ ions during the charge/discharge processes, which increases the capacity and rate capability of the electrode. It is the first time that the evolution of core-shell α-Fe_2O_3@Carbon changing to flower-like networks during lithiation/de-lithiation has been reported.

Electrochemical performance and structure evolution of core-shell nano-ring α-Fe2O3@Carbon anodes for lithium-ion batteries

Science.gov (United States)

Sun, Yan-Hui; Liu, Shan; Zhou, Feng-Chen; Nan, Jun-Min

2016-12-01

Core-shell nano-ring α-Fe2O3@Carbon (CSNR) composites with different carbon content (CSNR-5%C and CSNR-13%C) are synthesized using a hydrothermal method by controlling different amounts of glucose and α-Fe2O3 nano-rings with further annealing. The CSNR electrodes exhibit much improved specific capacity, cycling stability and rate capability compared with that of bare nano-ring α-Fe2O3 (BNR), which is attributed to the core-shell nano-ring structure of CSNR. The carbon shell in the inner and outer surface of CSNR composite can increase electron conductivity of the electrode and inhibit the volume change of α-Fe2O3 during discharge/charge processes, and the nano-ring structure of CSNR can buffer the volume change too. The CSNR-5%C electrode shows super high initial discharge/charge capacities of 1570/1220 mAh g-1 and retains 920/897 mAh g-1 after 200 cycles at 500 mA g-1 (0.5C). Even at 2000 mA g-1 (2C), the electrode delivers the initial capacities of 1400/900 mAh g-1, and still maintains 630/610 mAh g-1 after 200 cycles. The core-shell nano-rings opened during cycling and rebuilt a new flower-like structure consisting of α-Fe2O3@Carbon nano-sheets. The space among the nano-sheet networks can further buffer the volume expansion of α-Fe2O3 and facilitate the transportation of electrons and Li+ ions during the charge/discharge processes, which increases the capacity and rate capability of the electrode. It is the first time that the evolution of core-shell α-Fe2O3@Carbon changing to flower-like networks during lithiation/de-lithiation has been reported.

Testing and analysis to determine the shell thickness required to prevent puncture

International Nuclear Information System (INIS)

Ammerman, D.J.; Radloff, H.D.; Eifert, E.J.

1998-05-01

Type B radioactive material packages are required to withstand a hypothetical puncture accident of a free fall from a height of one meter onto a 15 cm diameter mild steel puncture probe. For many packages it is desirable to have this accident event not result in puncture or tearing of the outer shell of the package. The wall thickness necessary to prevent this has historically been determined by test or the use of empirical relations. This technique generally results in overly conservative designs, but the degree of conservatism is uncertain. The use of modem finite element codes to determine package response to puncture accidents can result in designs that are both safe and economical. The work reported in this paper is aimed at developing a method to analytically determine the wall thickness required to prevent puncture. For designers and regulators to have confidence in this analytical method, however, it must be benchmarked against test results. A series of tests has been conducted with differing shell thicknesses, shell materials of mild steel and stainless steel, and shell backing materials of lead, foam, and air. The results of these tests have been compared with pre-test analytical predictions of the response obtained from the nonlinear transient dynamic finite element program PRONTO-2D. From this comparison it can be seen that the finite element method can accurately predict the response of packages to puncture accidents. This implies that an analytical technique based on the finite element method can be used to design packages having known response and margin of safety against tearing of the outer shell. In addition, the analytical technique can accurately predict the deformed shape of the package following the test. This may be important for subsequent calculations, such as external dose and heat input during a thermal event

Design of Ultra High Performance Fiber Reinforced Concrete Shells

DEFF Research Database (Denmark)

Jepsen, Michael S.; Lambertsen, Søren Heide; Damkilde, Lars

2013-01-01

Fiber Reinforced Concrete shell. The major challenge in the design phase has been securing sufficient stiffness of the structure while keeping the weight at a minimum. The weight/stiffness issue has been investigated by means of the finite element method, to optimize the structure regarding overall......The paper treats the redesign of the float structure of the Wavestar wave energy converter. Previously it was designed as a glass fiber structure, but due to cost reduction requirements a redesign has been initiated. The new float structure will be designed as a double curved Ultra High Performance...

Effect of solid state fermentation of peanut shell on its dye adsorption performance.

Science.gov (United States)

Liu, Jiayang; Wang, Zhixin; Li, Hongyan; Hu, Changwei; Raymer, Paul; Huang, Qingguo

2018-02-01

The effect of solid state fermentation of peanut shell to produce beneficial laccase and on its dye adsorption performance was evaluated. The resulting residues from solid fermentation were tested as sorbents (designated as SFs) in comparison to the raw peanut shell (RPS) for their ability to remove crystal violet from water. The fermentation process reduced the adsorption capacity (q m ) of SF by about 50%, and changed the sorptive behavior when compared to the RPS. The Langmuir model was more suitable for fitting adsorption by SFs. q m was positively correlated with the surface area of peanut shell, but negatively correlated with acid detergent lignin content. For all the sorbents tested, the process was spontaneous and endothermic, and the adsorption followed both the pseudo 1st and 2nd order kinetic model and the film diffusion model. Dye adsorption efficiency was greater when SFs dispersed solution than when placed in filter packets. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ancient limpet shells as paleo-environmental and ethno-archaeological archives: the case of Beniguet Island's shell middens (Iroise Sea)

Science.gov (United States)

Cudennec, Jean-François; Stephan, Pierre; Dupont, Catherine; Pailler, Yvan; Thébault, Julien; Schöne, Bernd; Paulet, Yves-Marie

2017-04-01

During the winter 2013-2014, severe storm events caused a coastal erosion in the southern part of the Beniguet Island (Brittany, France). The associated shoreline retreat had uncovered three layers of shell middens interbedded into an aeolian sand dune deposit. From several radiocarbon dating crossed with the study of ceramic and lithic contents, the shell middens were dated to the Final Neolithic (2400 BC), the Early Bronze Age (2000 BC) and the Early Middle Age (800 AD) respectively. This site offers a unique opportunity to collect two types of information: palaeo-environmental (palaeo-temperature of sea water) and archaeological (determination of harvest season). In this study, we focus on gastropod of the genus Patella which represent 90% of the remains found in this midden. This organism is potentially a highly valuable archive for these environments because they are intertidal and relatively sedentary. We studied the growth rings in the outer calcitic layer of individual limpet shells from the Neolithic, Early Bronze Age and Present Day populations. We report here the results of δ18O analyses. We found a similarity between the reconstructed palaeo-temperature in the Neolithic and the Present periods (between 13 and 14°C in summer and about 8 - 9°C in winter). However, palaeo-temperatures of the Early Bronze Age shells are significantly lower in winter (5 - 6 °C). Moreover, the initial results of the δ18O analyses at the margin of these shells showed that they were harvested during a specific season (end of spring or early summer). Additional work will be done to address questions about shell growth dynamics of these species. These results confirm the interest of using ancient limpet shells as palaeo-environmental and archaeological archives.

Modification of Ag shell on upconversion populating paths of NaYF{sub 4}:Yb{sup 3+},Er{sup 3+}@Ag nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Sun, Jiao [Norman Bethune College of Medicine, Jilin University, Changchun, Jilin Province 130021 (China); Liu, Haipeng [Department of Plastic and Reconstructive Surgery, The First Hospital of JiLin University, Jilin Province 130021 (China); Wu, Di [Norman Bethune College of Medicine, Jilin University, Changchun, Jilin Province 130021 (China); Dong, Biao, E-mail: dongb@jlu.edu.cn [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Sun, Liankun [Norman Bethune College of Medicine, Jilin University, Changchun, Jilin Province 130021 (China)

2013-01-15

NaYF{sub 4}:Yb{sup 3+},Er{sup 3+}@Ag core-shell nanocomposites were prepared. Due to the outer shell of Ag, some modifications were found on the upconversion (UC) processes of NaYF{sub 4}:Yb{sup 3+},Er{sup 3+} core nanoparticles (NPs) caused by the co-interaction of surface effect, surface plasma absorption effect and local thermal effect under infrared radiation. Upon 980 nm excitation, the relative UC intensity of the green ({sup 2}H{sub 11/2}, {sup 4}S{sub 3/2}-{sup 4}I{sub 15/2}) to red ({sup 4}F{sub 9/2}-{sup 4}I{sub 15/2}) and the slope of power-dependence increased intensively, and three-photon population process for the green level appeared. -- Highlights: Black-Right-Pointing-Pointer NaYF{sub 4}:Yb{sup 3+},Er{sup 3+}@Ag core/shell nanocomposites were fabricated. Black-Right-Pointing-Pointer The coating of Ag outer shell leads to the increase of the green UCL. Black-Right-Pointing-Pointer Three-photon population process for the green level appeared after Ag coating.

High performance of PbSe/PbS core/shell quantum dot heterojunction solar cells: short circuit current enhancement without the loss of open circuit voltage by shell thickness control.

Science.gov (United States)

Choi, Hyekyoung; Song, Jung Hoon; Jang, Jihoon; Mai, Xuan Dung; Kim, Sungwoo; Jeong, Sohee

2015-11-07

We fabricated heterojunction solar cells with PbSe/PbS core shell quantum dots and studied the precisely controlled PbS shell thickness dependency in terms of optical properties, electronic structure, and solar cell performances. When the PbS shell thickness increases, the short circuit current density (JSC) increases from 6.4 to 11.8 mA cm(-2) and the fill factor (FF) enhances from 30 to 49% while the open circuit voltage (VOC) remains unchanged at 0.46 V even with the decreased effective band gap. We found that the Fermi level and the valence band maximum level remain unchanged in both the PbSe core and PbSe/PbS core/shell with a less than 1 nm thick PbS shell as probed via ultraviolet photoelectron spectroscopy (UPS). The PbS shell reduces their surface trap density as confirmed by relative quantum yield measurements. Consequently, PbS shell formation on the PbSe core mitigates the trade-off relationship between the open circuit voltage and the short circuit current density. Finally, under the optimized conditions, the PbSe core with a 0.9 nm thick shell yielded a power conversion efficiency of 6.5% under AM 1.5.

THE STRESS STATE OF THE RADIALLY INHOMOGENEOUS HEMISPHERICAL SHELL UNDER LOCALLY DISTRIBUTED VERTICAL LOAD

Directory of Open Access Journals (Sweden)

Andreev Vladimir Igorevich

2018-01-01

Full Text Available Subject: one of the promising trends in the development of structural mechanics is the development of methods for solving problems in the theory of elasticity for bodies with continuous inhomogeneity of any deformation characteristics: these methods make it possible to use the strength of the material most fully. In this paper, we consider the two-dimensional problem for the case when a vertical, locally distributed load acts on the hemisphere and the inhomogeneity is caused by the influence of the temperature field. Research objectives: derive governing system of equations in spherical coordinates for determination of the stress state of the radially inhomogeneous hemispherical shell under locally distributed vertical load. Materials and methods: as a mechanical model, we chose a thick-walled reinforced concrete shell (hemisphere with inner and outer radii a and b, respectively, b > a. The shell’s parameters are a = 3.3 m, b = 4.5 m, Poisson’s ratio ν = 0.16; the load parameters are f = 10MPa - vertical localized load distributed over the outer face, θ0 = 30°, temperature on the internal surface of the shell Ta = 500 °C, temperature on the external surface of the shell Tb = 0 °C. The resulting boundary-value problem (a system of differential equations with variable coefficients is solved using the Maple software package. Results: maximal compressive stresses σr with allowance for material inhomogeneity are reduced by 10 % compared with the case when the inhomogeneity is ignored. But it is not so important compared with a 3-fold decrease in the tensile stress σθ on the inner surface and a 2-fold reduction in the tensile stress σθ on the outer surface of the hemisphere as concretes generally have a tensile strength substantially smaller than the compressive strength. Conclusions: the method presented in this article makes it possible to reduce the deformation characteristics of the material, i.e. it leads to a reduction in stresses

Comparative Influences of Fluid and Shell on Modeled Ejection Performance of a Piezoelectric Micro-Jet

Directory of Open Access Journals (Sweden)

Kai Li

2017-01-01

Full Text Available The piezoelectric micro-jet, which can achieve the drop-on-demand requirement, is based on ink-jet technology and small droplets can be ejected out by precise control. The droplets are driven out of the nozzle by the acoustic pressure waves which are generated by the piezoelectric vibrator. The propagation processes of the acoustic pressure waves are affected by the acoustic properties of the fluid and the shell material of the micro-jet, as well as the excitations and the structure sizes. The influences of the fluid density and acoustic velocity in the fluid on the nozzle pressure and support reaction force of the vibrator are analyzed in this paper. The effects of the shell material on the ejection performance are studied as well. In order to improve the ejection performance of the micro-jet, for ejecting a given fluid, the recommended methods of selecting the shell material and adjusting excitations are provided based on the results, and the influences of the factors on working frequencies are obtained as well.

A novel shell-structure cell microcarrier (SSCM) for cell transplantation and bone regeneration medicine.

Science.gov (United States)

Su, Kai; Gong, Yihong; Wang, Chunming; Wang, Dong-An

2011-06-01

The present study aims to develop a novel open and hollow shell-structure cell microcarrier (SSCM) to improve the anchorage-dependent cell (ADC) loading efficiency, increase the space for cell proliferation and tissue regeneration, and better propel its therapeutic effects. Gelatin particles were prepared with oil/water/oil (o/w/o) technique and modified by an adjustable surface crosslinking technique and subsequent release of uncrosslinked material. Optical microscopy and scanning electron microscopy (SEM) were utilized to observe the morphologies of the microcarriers. Cell loading tests were performed to evaluate the biocompatibilities and effect on osteogenesis of SSCM. SSCMs were successfully fabricated via the surface technique. The shell-structure could allow the cell to attach and grow on both outer and inner surface of sphere and provide adequate space for cell proliferation and extracellular matrix (ECM) secretion. The cell loading rate, proliferation rate and osteogenesis-related gene expressions on the SSCMs were higher than those on the spherical gelatin microcarriers. The outstanding performance of injectable SSCMs endowed with favorable micro-structure, desirable cytocompatibility and enhanced cell affinity makes them as a good choice as cell delivery vehicle for transplanting therapeutic cells towards the scope of tissue regeneration.

Ageing and Performance Studies of the Outer Tracker of the LHCb Detector; Alterungsstudien und Studium der Betriebseigenschaften des Outer Trackers des LHCb Detektors

Energy Technology Data Exchange (ETDEWEB)

Haas, T.

2007-11-07

The Outer Tracker is part of the LHCb tracking system. It uses drift chamber to measure the track of a particle. The straws have a length of 2.5m and a diameter of 4.9 mm. They are operated in proportional mode and should measure tracks with a precision of 200 {mu}m per hit. In the first part, this thesis presents the results of a performance study for the Outer Tracker, focussing on spatial resolution and efficiency. The main part of this thesis deals with aging studies. Neither a test with 8 keV X-rays nor with highly ionising protons showed any change in the module behavior due to aging. The acceleration factors compared to LHCb were 8-180 (anode current >80 nA/cm) in the most irradiated areas. A charge of up to 3 C/cm was accumulated. Aging tests at anode currents below 15 nA/cm (acceleration factor 1) showed a significant gain drop for the already produced modules after only a few days (1-2 mC/cm) of irradiation. The aging depends on several parameters like gas flow velocity or gas mixture. There is no aging for anode currents >12 nA/cm. This aging is an effect of outgassing material used in the module. Tests showed that the outgassing is probably caused by the epoxy adhesive. Flushing and warming the modules reduce the aging significantly. As things are, the Outer Tracker modules can be operated in LHCb for several years. (orig.)

Versatile post-functionalization of the external shell of cowpea chlorotic mottle virus by using click chemistry

NARCIS (Netherlands)

Hommersom, C.A.; Matt, B.D.; van der Ham, A.M.; Cornelissen, Jeroen Johannes Lambertus Maria; Katsonis, Nathalie Hélène

2014-01-01

We present the modification of the outer protein shell of cowpea chlorotic mottle virus (CCMV) with linear and strained alkyne groups. These functionalized protein capsids constitute valuable platforms for post-functionalization via click chemistry. After modification, the integrity of the capsid

Au@TiO2 yolk-shell nanostructures for enhanced performance in both photoelectric and photocatalytic solar conversion

Science.gov (United States)

He, Qinrong; Sun, Hang; Shang, Yinxing; Tang, Yanan; She, Ping; Zeng, Shan; Xu, Kongliang; Lu, Guolong; Liang, Song; Yin, Shengyan; Liu, Zhenning

2018-05-01

Solar energy conversion is an important field gaining increasing interest. Herein, bio-inspired Au@TiO2 yolk-shell nanoparticles (NPs) have been prepared via a facial one-pot hydrothermal approach. The Au@TiO2 yolk-shell NPs can self-assemble into 3D-structure to form photoelectrode for photoelectric conversion. The obtained photoelectrode demonstrates a swift and stable photocurrent of 3.5 μA/cm2, which is 4.2 and 1.6 times higher than those of the photocurrents generated by the counterparts of commercial TiO2 and Au@TiO2 core-shell NPs, respectively. Moreover, compared to the commercial TiO2 and Au@TiO2 core-shell NPs, the Au@TiO2 yolk-shell NPs also exhibit superior photocatalytic activity, delivering a H2 evolution rate of 4.92 mmol/g h. The performance improvement observed for the Au@TiO2 yolk-shell NPs is likely contributed by two synergistic factors, i.e. the incorporation of AuNPs and the unique hollow structure, which benefit the activity by simultaneously enhancing light utilization, charge separation and reaction site accessibility. The rational design and fabrication of Au@TiO2 yolk-shell NPs hold great promise for future application in efficient solar energy conversion.

Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

OpenAIRE

Preti, Raffaella

2016-01-01

The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large am...

Elastic stability of cylindrical shells with soft elastic cores: Biomimicking natural tubular structures

Science.gov (United States)

Karam, Gebran Nizar

1994-01-01

Thin walled cylindrical shell structures are widespread in nature: examples include plant stems, porcupine quills, and hedgehog spines. All have an outer shell of almost fully dense material supported by a low density, cellular core. In nature, all are loaded in combination of axial compression and bending: failure is typically by buckling. Natural structures are often optimized. Here we have analyzed the elastic buckling of a thin cylindrical shell supported by an elastic core to show that this structural configuration achieves significant weight saving over a hollow cylinder. The results of the analysis are compared with data from an extensive experimental program on uniaxial compression and four point bending tests on silicone rubber shells with and without compliant foam cores. The analysis describes the results of the mechanical tests well. Characterization of the microstructures of several natural tubular structures with foamlike cores (plant stems, quills, and spines) revealed them to be close to the optimal configurations predicted by the analytical model. Biomimicking of natural cylindrical shell structures and evolutionary design processes may offer the potential to increase the mechanical efficiency of engineering cylindrical shells.

Design, performance, and calibration of the CMS hadron-outer calorimeter

International Nuclear Information System (INIS)

Abdullin, S.; Gavrilov, V.; Ilyina, N.; Kaftanov, V.; Kisselevich, I.; Kolossov, V.; Krokhotin, A.; Kuleshov, S.; Pozdnyakov, A.; Safronov, G.; Semenov, S.; Stolin, V.; Ulyanov, A.; Abramov, V.; Goncharov, P.; Kalinin, A.; Khmelnikov, A.; Korablev, A.; Korneev, Y.; Krinitsyn, A.; Kryshkin, V.; Lukanin, V.; Pikalov, V.; Ryazanov, A.; Talov, V.; Turchanovich, L.; Volkov, A.; Acharya, B.; Aziz, T.; Banerjee, Sudeshna; Banerjee, Sunanda; Bose, S.; Chendvankar, S.; Deshpande, P.V.; Dugad, S.; Ganguli, S.N.; Guchait, M.; Gurtu, A.; Kalmani, S.; Krishnaswamy, M.R.; Maity, M.; Majumder, G.; Mazumdar, K.; Mondal, N.; Nagaraj, P.; Narasimham, V.S.; Patil, M.; Reddy, L.; Satyanarayana, B.; Sharma, S.; Sudhakar, K.; Tonwar, S.; Verma, P.; Adam, N.; Fisher, W.; Halyo, V.; Hunt, A.; Jones, J.; Laird, E.; Landsberg, G.; Marlow, D.; Tully, C.; Werner, J.; Adams, M.; Bard, R.; Burchesky, K.; Qian, W.; Akchurin, N.; Berntzon, L.; Carrell, K.; Guemues, K.; Jeong, C.; Kim, H.; Lee, S.W.; Popescu, S.; Roh, Y.; Spezziga, M.; Thomas, R.; Volobouev, I.; Wigmans, R.; Yazgan, E.; Akgun, U.; Albayrak, E.; Ayan, S.; Clarida, W.; Debbins, P.; Duru, F.; Ingram, D.; Merlo, J.P.; Mestvirishvili, A.; Miller, M.; Moeller, A.; Norbeck, E.; Olson, J.; Onel, Y.; Ozok, F.; Schmidt, I.; Yetkin, T.; Anderson, E.W.; Hauptman, J.; Antchev, G.; Arcidy, M.; Hazen, E.; Heister, A.; Lawlor, C.; Lazic, D.; Machado, E.; Posch, C.; Rohlf, J.; Sulak, L.; Varela, F.; Wu, S.X.; Aydin, S.; Bakirci, M.N.; Cerci, S.; Dumanoglu, I.; Erturk, S.; Eskut, E.; Kayis-Topaksu, A.; Onengut, G.; Ozkurt, H.; Polatoz, A.; Sogut, K.; Topakli, H.; Vergili, M.; Baarmand, M.; Mermerkaya, H.; Ralich, R.M.; Vodopiyanov, I.; Babich, K.; Golutvin, I.; Kalagin, V.; Kosarev, I.; Ladygin, V.; Mescheryakov, G.; Moissenz, P.; Petrosyan, A.; Rogalev, E.; Smirnov, V.; Vishnevskiy, A.; Volodko, A.; Zarubin, A.; Baden, D.; Eno, S.; Grassi, T.; Jarvis, C.; Kellogg, R.; Kunori, S.; Skuja, A.; Wang, L.; Wetstein, M.; Barnes, V.; Laasanen, A.; Pompos, A.; Bawa, H.; Beri, S.; Bhandari, V.; Bhatnagar, V.; Kaur, M.; Kohli, J.; Kumar, A.; Singh, B.; Singh, J.B.; Baiatian, G.; Sirunyan, A.; Bencze, G.; Laszlo, A.; Pal, A.; Vesztergombi, G.; Zalan, P.; Bhatti, A.; Bodek, A.; Budd, H.; Chung, Y.; Barbaro, P. de; Haelen, T.; Bose, T.; Esen, S.; Vanini, A.; Camporesi, T.; Visser, T. de; Efthymiopoulos, I.; Cankocak, K.; Cremaldi, L.; Reidy, J.; Sanders, D.A.; Cushman, P.; Ma, Y.; Sherwood, B.; Damgov, J.; Piperov, S.; Deliomeroglu, M.; Guelmez, E.; Isiksal, E.; Kaya, M.; Kaya, O.; Ozkorucuklu, S.; Sonmez, N.; Demianov, A.; Ershov, A.; Gribushin, A.; Kodolova, O.; Petrushanko, S.; Sarycheva, L.; Teplov, K.; Vardanyan, I.; Diaz, J.; Gaultney, V.; Kramer, L.; Linn, S.; Lobolo, L.; Markowitz, P.; Martinez, G.; Dimitrov, L.; Genchev, V.; Vankov, I.; Elias, J.; Elvira, D.; Freeman, J.; Green, D.; Los, S.; Ronzhin, A.; Sergeyev, S.; Suzuki, I.; Vidal, R.; Whitmore, J.; Emeliantchik, I.; Mossolov, V.; Shumeiko, N.; Stefanovich, R.; Fenyvesi, A.; Gamsizkan, H.; Murat Gueler, A.; Ozkan, C.; Sekmen, S.; Serin, M.; Sever, R.; Zeyrek, M.; Gleyzer, S.; Hagopian, S.; Hagopian, V.; Johnson, K.; Grinev, B.; Lubinsky, V.; Senchishin, V.; Hashemi, M.; Mohammadi-Najafabadi, M.; Paktinat, S.; Heering, A.; Karmgard, D.; Ruchti, R.; Levchuk, L.; Sorokin, P.; Litvintsev, D.; Mans, J.; Penzo, A.; Podrasky, V.; Sanzeni, C.; Winn, D.; Vlassov, E.

2008-01-01

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E T measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS. (orig.)

Design, performance, and calibration of the CMS hadron-outer calorimeter

Energy Technology Data Exchange (ETDEWEB)

Abdullin, S.; Gavrilov, V.; Ilyina, N.; Kaftanov, V.; Kisselevich, I.; Kolossov, V.; Krokhotin, A.; Kuleshov, S.; Pozdnyakov, A.; Safronov, G.; Semenov, S.; Stolin, V.; Ulyanov, A. [ITEP, Moscow (Russian Federation); Abramov, V.; Goncharov, P.; Kalinin, A.; Khmelnikov, A.; Korablev, A.; Korneev, Y.; Krinitsyn, A.; Kryshkin, V.; Lukanin, V.; Pikalov, V.; Ryazanov, A.; Talov, V.; Turchanovich, L.; Volkov, A. [IHEP, Protvino (Russian Federation); Acharya, B.; Aziz, T.; Banerjee, Sudeshna; Banerjee, Sunanda; Bose, S.; Chendvankar, S.; Deshpande, P.V.; Dugad, S.; Ganguli, S.N.; Guchait, M.; Gurtu, A.; Kalmani, S.; Krishnaswamy, M.R.; Maity, M.; Majumder, G.; Mazumdar, K.; Mondal, N.; Nagaraj, P.; Narasimham, V.S.; Patil, M.; Reddy, L.; Satyanarayana, B.; Sharma, S.; Sudhakar, K.; Tonwar, S.; Verma, P. [Tata Inst. of Fundamental Research, Mumbai (India); Adam, N.; Fisher, W.; Halyo, V.; Hunt, A.; Jones, J.; Laird, E.; Landsberg, G.; Marlow, D.; Tully, C.; Werner, J. [Princeton Univ., NJ (United States); Adams, M.; Bard, R.; Burchesky, K.; Qian, W. [Univ. of Illinois, Chicago, IL (United States); Akchurin, N.; Berntzon, L.; Carrell, K.; Guemues, K.; Jeong, C.; Kim, H.; Lee, S.W.; Popescu, S.; Roh, Y.; Spezziga, M.; Thomas, R.; Volobouev, I.; Wigmans, R.; Yazgan, E. [Texas Tech Univ., Lubbock, TX (United States); Akgun, U.; Albayrak, E.; Ayan, S.; Clarida, W.; Debbins, P.; Duru, F.; Ingram, D.; Merlo, J.P.; Mestvirishvili, A.; Miller, M.; Moeller, A.; Norbeck, E.; Olson, J.; Onel, Y.; Ozok, F.; Schmidt, I.; Yetkin, T. [Univ. of Iowa, Iowa City, IA (United States); Anderson, E.W.; Hauptman, J. [Iowa State Univ., Ames, IA (United States); Antchev, G.; Arcidy, M.; Hazen, E.; Heister, A.; Lawlor, C.; Lazic, D.; Machado, E.; Posch, C.; Rohlf, J.; Sulak, L.; Varela, F.; Wu, S.X. [Boston Univ., MA (United States); Aydin, S.; Bakirci, M.N.; Cerci, S.; Dumanoglu, I.; Erturk, S.; Eskut, E.; Kayis-Topaksu, A.; Onengut, G.; Ozkurt, H.; Polatoz, A.; Sogut, K. [and others

2008-10-15

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E{sub T} measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS. (orig.)

Theoretical Study of Local Surface Plasmon Resonances on a Dielectric-Ag Core-Shell Nanosphere Using the Discrete-Dipole Approximation Method

International Nuclear Information System (INIS)

Ma Ye-Wan; Wu Zhao-Wang; Zhang Li-Hua; Liu Wan-Fang; Zhang Jie

2015-01-01

The local surface plasmon resonances (LSPRs) of dielectric-Ag core-shell nanospheres are studied by the discretedipole approximation method. The result shows that LSPRs are sensitive to the surrounding medium refractive index, which shows a clear red-shift with the increasing surrounding medium refractive index. A dielectric-Ag core-shell nanosphere exhibits a strong coupling between the core and shell plasmon resonance modes. LSPRs depend on the shell thickness and the composition of dielectric-core and metal-shell. LSPRs can be tuned over a longer wavelength range by changing the ratio of core to shell value. The lower energy mode ω_− shows a red-shift with the increasing dielectric-core value and the inner core radius, while blue-shifted with the increasing outer shell thickness. The underlying mechanisms are analyzed with the plasmon hybridization theory and the phase retardation effect. (paper)

Synthesis of Various Metal/TiO2 Core/shell Nanorod Arrays

Science.gov (United States)

Zhu, Wei; Wang, Guan-zhong; Hong, Xun; Shen, Xiao-shuang

2011-02-01

We present a general approach to fabricate metal/TiO2 core/shell nanorod structures by two-step electrodeposition. Firstly, TiO2 nanotubes with uniform wall thickness are prepared in anodic aluminum oxide (AAO) membranes by electrodeposition. The wall thickness of the nanotubes could be easily controlled by modulating the deposition time, and their outer diameter and length are only limited by the channel diameter and the thickness of the AAO membranes, respectively. The nanotubes' tops prepared by this method are open, while the bottoms are connected directly with the Au film at the back of the AAO membranes. Secondly, Pd, Cu, and Fe elements are filled into the TiO2 nanotubes to form core/shell structures. The core/shell nanorods prepared by this two-step process are high density and free-standing, and their length is dependent on the deposition time.

Preliminary performance assessment strategy for single-shell tank waste disposal

International Nuclear Information System (INIS)

Sonnichsen, J.C. Jr.

1991-10-01

The disposal of the waste stored in single-shell tanks at the Hanford Site is recognized as a major environmental concern. A comprehensive program has been initiated to evaluate the various alternatives available for disposal of these wastes. Theses wastes will be disposed of in a manner consistent with applicable laws and regulations. Long-term waste isolation is one measure of performance that will be used for purposes of selection. The performance of each disposal alternative will be simulated using numerical models. Contained herein is a discussion of the strategy that has and continues to evolve to establish a general analytical framework to evaluate this performance. This general framework will be used to construct individual models of each waste disposal alternative selected for purposes of evaluation. 30 refs., 3 figs

Statistical approach of inner-shell ionization in 0.1-1.625 MeV/u Cu + Bi collisions

International Nuclear Information System (INIS)

Piticu, I.; Ciortea, C.; Enulescu, A.; Fluerasu, D.; Szilagyi, S.Z.; Micu, M.; Dumitriu, D.

1999-01-01

Experimental data of inner-shell ionization cross sections and outer-shell ionization probabilities per electron, obtained for the collision system. Cu + Bi in the energy range of 0.1-1.625 MeV/u, are in good agreement with the predictions of the statistical model of Mittleman and Wilets. The found dependence of the diffusion constant determined for different final vacancy states on the excitation (ionization) energy is in fair agreement with the model prediction. (orig.)

Statistical approach of inner-shell ionization in 0.1-1.625 MeV/u Cu + Bi collisions

Energy Technology Data Exchange (ETDEWEB)

Piticu, I.; Ciortea, C.; Enulescu, A.; Fluerasu, D.; Szilagyi, S.Z.; Micu, M.; Dumitriu, D. [Horia Hulubei National Inst. of Physics and Nuclear Engineering, Bucharest (Romania). Dept. of Experimental Physics

1999-07-01

Experimental data of inner-shell ionization cross sections and outer-shell ionization probabilities per electron, obtained for the collision system. Cu + Bi in the energy range of 0.1-1.625 MeV/u, are in good agreement with the predictions of the statistical model of Mittleman and Wilets. The found dependence of the diffusion constant determined for different final vacancy states on the excitation (ionization) energy is in fair agreement with the model prediction. (orig.)

ZnO@MnO2 Core-Shell Nanofiber Cathodes for High Performance Asymmetric Supercapacitors.

Science.gov (United States)

Radhamani, A V; Shareef, K M; Rao, M S Ramachandra

2016-11-09

Asymmetric supercapacitors (ASCs) with aqueous electrolyte medium have recently become the focus of increasing research. For high performance ASCs, selection of cathode materials play a crucial role, and core-shell nanostructures are found to be a good choice. We successfully synthesized, ZnO@MnO 2 core-shell nanofibers (NFs) by modification of high-aspect-ratio-electrospun ZnO NFs hydrothermally with MnO 2 nanoflakes. High conductivity of the ZnO NFs and the exceptionally high pseudocapacitive nature of MnO 2 nanoflakes coating delivered a specific capacitance of 907 Fg -1 at 0.6 Ag -1 for the core-shell NFs. A simple and cost-effective ASC construction was demonstrated with ZnO@MnO 2 NFs as a battery-type cathode material and a commercial-quality activated carbon as a capacitor-type anode material. The fabricated device functioned very well in a voltage window of 0-2.0 V, and a red-LED was illuminated using a single-celled fabricated ASC device. It was found to deliver a maximum energy density of 17 Whkg -1 and a power density of 6.5 kWkg -1 with capacitance retention of 94% and Coulombic efficiency of 100%. The novel architecture of the ZnO@MnO 2 core-shell nanofibrous material implies the importance of using simple design of fiber-based electrode material by mere changes of core and shell counterparts.

Multi-core MgO NPs(at)C core-shell nanospheres for selective CO2 capture under mild conditions

International Nuclear Information System (INIS)

Tae Kyung Kim; Kyung Joo Lee; Hoi Ri Moon; Junhan Yuh; Sang Kyu Kwak

2014-01-01

The core-shell structures have attracted attention in catalysis, because the outer shells isolate the catalytically active NP cores and prevent the possibility of sintering of core particles during catalytic reaction under physically and chemically harsh conditions. We aimed to adopt this core-shell system for CO 2 sorption materials. In this study, a composite material of multi-core 3 nm-sized magnesium oxide nanoparticles embedded in porous carbon nanospheres (MgO NPs(at)C) was synthesized by a gas phase reaction via a solvent-free process. It showed selective CO 2 adsorption capacity over N 2 under mild regeneration conditions. (authors)

Investigation of the structure change of atomic shells due to uranium ionization by the Dirac-Fock-Slater method

International Nuclear Information System (INIS)

Shchornak, G.

1979-01-01

The influence of outer vacancies in the atomic shells of uranium on the atomic shell structure is claculated by the Dirac-Fock-Slater method. It is found out that the energy of the X-ray transitions increases due to the detachment of the electrons with the lowest binding energies. The electron detachment from the subshells of the 4f level gives rise to negative energy shifts of the X-ray transitions.(author)

Control of the Helicity Content of a Gun-Generated Spheromak by Incorporating a Conducting Shell into a Magnetized Coaxial Plasma Gun

Science.gov (United States)

Matsumoto, Tadafumi; Sekiguchi, Jun'ichi; Asai, Tomohiko

In the formation of magnetized plasmoid by a magnetized coaxial plasma gun (MCPG), the magnetic helicity content of the generated plasmoid is one of the critical parameters. Typically, the bias coil to generate a poloidal flux is mounted either on the outer electrode or inside the inner electrode. However, most of the flux generated in the conventional method spreads even radially outside of the formation region. Thus, only a fraction of the total magnetic flux is actually exploited for helicity generation in the plasmoid. In the proposed system, the plasma gun incorporates a copper shell mounted on the outer electrode. By changing the rise time of the discharge bias coil current and the geometrical structure of the shell, the magnetic field structure and its time evolution can be controlled. The effect of the copper shell has been numerically simulated for the actual gun structure, and experimentally confirmed. This may increase the magnetic helicity content results, through increased poloidal magnetic field.

Autoradiographic study on the distribution of 241Am in the shell of the freshwater zebra mussel Dreissena polymorpha

International Nuclear Information System (INIS)

Zuykov, M.; Pelletier, E.; Rouleau, C.; Popov, L.; Fowler, S.W.; Orlova, M.

2009-01-01

Autoradiography was used to identify α-track distributions in a series of shell sections from live mussels Dreissena polymorpha Pallas and dissected shells of dead mussels obtained from laboratory experiments using relatively high concentrations of 241 Am in the exposure media, a required condition for successful use of this autoradiographic technique. A comparable distribution of α-tracks was recorded on autoradiographs from both live and dead shells suggesting that metabolism does not lead to any sizable changes in the process of 241 Am adsorption (present in the extrapallial fluid) onto the inner surface of shell. Autoradiographs showed a preferential accumulation of 241 Am in the organic periostracum, whereas the outer and inner shell layers were characterized by a relatively low α-tracks density. No α-tracks were observed in the central part of the shell in any of the samples. These observations will be useful for the development of a general model to explain bioaccumulation and biosorption processes of radionuclides into mollusk shells. (author)

Electrospun pH-sensitive core-shell polymer nanocomposites fabricated using a tri-axial process.

Science.gov (United States)

Yang, Chen; Yu, Deng-Guang; Pan, Deng; Liu, Xin-Kuan; Wang, Xia; Bligh, S W Annie; Williams, Gareth R

2016-04-15

A modified tri-axial electrospinning process was developed for the generation of a new type of pH-sensitive polymer/lipid nanocomposite. The systems produced are able to promote both dissolution and permeation of a model poorly water-soluble drug. First, we show that it is possible to run a tri-axial process with only one of the three fluids being electrospinnable. Using an electrospinnable middle fluid of Eudragit S100 (ES100) with pure ethanol as the outer solvent and an unspinnable lecithin-diclofenac sodium (PL-DS) core solution, nanofibers with linear morphology and clear core/shell structures can be fabricated continuously and smoothly. X-ray diffraction proved that these nanofibers are structural nanocomposites with the drug present in an amorphous state. In vitro dissolution tests demonstrated that the formulations could preclude release in acidic conditions, and that the drug was released from the fibers in two successive steps at neutral pH. The first step is the dissolution of the shell ES100 and the conversion of the core PL-DS into sub-micron sized particles. This frees some DS into solution, and later the remaining DS is gradually released from the PL-DS particles through diffusion. Ex vivo permeation results showed that the composite nanofibers give a more than twofold uplift in the amount of DS passing through the colonic membrane as compared to pure DS; 74% of the transmitted drug was in the form of PL-DS particles. The new tri-axial electrospinning process developed in this work provides a platform to fabricate structural nanomaterials, and the core-shell polymer-PL nanocomposites we have produced have significant potential applications for oral colon-targeted drug delivery. A modified tri-axial electrospinning is demonstrated to create a new type of core-shell pH-sensitive polymer/lipid nanocomposites, in which an electrospinnable middle fluid is exploited to support the un-spinnable outer and inner fluids. The structural nanocomposites are able

Three-dimensional core-shell Fe{sub 2}O{sub 3} @ carbon/carbon cloth as binder-free anode for the high-performance lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaohua; Zhang, Miao [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Liu, Enzuo, E-mail: ezliu@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China); He, Fang; Shi, Chunsheng [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); He, Chunnian [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China); Li, Jiajun [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China)

2016-12-30

Highlights: • The 3D core-shell Fe{sub 2}O{sub 3}@C/CC structure is fabricated by simple hydrothermal route. • The composite connected 3D carbon networks consist of carbon cloth, Fe{sub 2}O{sub 3} nanorods and outer carbon layer. • The Fe{sub 2}O{sub 3}@C/CC used as binder-free anode in LIBs, demonstrates excellent performances. - Abstract: A facile and scalable strategy is developed to fabricate three dimensional core-shell Fe{sub 2}O{sub 3} @ carbon/carbon cloth structure by simple hydrothermal route as binder-free lithium-ion battery anode. In the unique structure, carbon coated Fe{sub 2}O{sub 3} nanorods uniformly disperse on carbon cloth which forms the conductive carbon network. The hierarchical porous Fe{sub 2}O{sub 3} nanorods in situ grown on the carbon cloth can effectively shorten the transfer paths of lithium ions and reduce the contact resistance. The carbon coating significantly inhibits pulverization of active materials during the repeated Li-ion insertion/extraction, as well as the direct exposure of Fe{sub 2}O{sub 3} to the electrolyte. Benefiting from the structural integrity and flexibility, the nanocomposites used as binder-free anode for lithium-ion batteries, demonstrate high reversible capacity and excellent cyclability. Moreover, this kind of material represents an alternative promising candidate for flexible, cost-effective, and binder-free energy storage devices.

Enhancement and prediction of modulus of elasticity of palm kernel shell concrete

International Nuclear Information System (INIS)

Alengaram, U. Johnson; Mahmud, Hilmi; Jumaat, Mohd Zamin

2011-01-01

Research highlights: → Micro-pores of size 16-24 μm were found on the outer surface of palm kernel shell. → Infilling of pores by mineral admixtures was evident. → Sand content influenced both modulus of elasticity and compressive strength. → Proposed equation predicts modulus of elasticity within ±1.5 kN/mm 2 of test results. -- Abstract: This paper presents results of an investigation conducted to enhance and predict the modulus of elasticity (MOE) of palm kernel shell concrete (PKSC). Scanning electron microscopic (SEM) analysis on palm kernel shell (PKS) was conducted. Further, the effect of varying sand and PKS contents and mineral admixtures (silica fume and fly ash) on compressive strength and MOE was investigated. The variables include water-to-binder (w/b) and sand-to-cement (s/c) ratios. Nine concrete mixes were prepared, and tests on static and dynamic moduli of elasticity and compressive strength were conducted. The SEM result showed presence of large number of micro-pores on PKS. The mineral admixtures uniformly filled the micro-pores on the outer surface of PKS. Further, the increase in sand content coupled with reduction in PKS content enhanced the compressive strength and static MOE: The highest MOE recorded in this investigation, 11 kN/mm 2 , was twice that previously published. Moreover, the proposed equation based on CEB/FIP code formula appears to predict the MOE close to the experimental values.

High-performance asymmetric supercapacitors based on core/shell cobalt oxide/carbon nanowire arrays with enhanced electrochemical energy storage

International Nuclear Information System (INIS)

Pan, G.X.; Xia, X.H.; Cao, F.; Chen, J.; Tang, P.S.; Zhang, Y.J.; Chen, H.F.

2014-01-01

Graphical abstract: - Highlights: • We prepared a self-supported porous Co 3 O 4 /C core/shell nanowire array. • Core/shell nanowire array showed high pseudo-capacitive properties. • Core/shell array structure was favorable for fast ion and electron transfer. - Abstract: High-reactivity electrode materials are indispensible for developing high-performance electrochemical energy storage devices. Herein, we report self-supported core/shell Co 3 O 4 /C nanowire arrays by using hydrothermal synthesis and chemical vapor deposition methods. A uniform and thin carbon shell is coated on the surface of Co 3 O 4 nanowire forming core/shell nanowires with diameters of ∼100 nm. Asymmetric supercapacitors have been assembled with the core/shell Co 3 O 4 /C nanowire arrays as the positive electrode and activated carbon (AC) as the negative electrode. The core/shell Co 3 O 4 /C nanowire arrays exhibit a specific capacity of 116 mAh g −1 at the working current of 100 mA (4 A g −1 ), and a long cycle life along with ∼ 92% retention after 8000 cycles at 4 A g −1 , higher than the unmodified Co 3 O 4 nanowire arrays (81 mAh g −1 at 4 A g −1 ). The introduction of uniform carbon layer into the core/shell structure is favorable for the enhancement of supercapacitor due to the improved electrical conductivity and reaction kinetics

Core-Shell Al-Polytetrafluoroethylene (PTFE) Configurations to Enhance Reaction Kinetics and Energy Performance for Nanoenergetic Materials.

Science.gov (United States)

Wang, Jun; Qiao, Zhiqiang; Yang, Yuntao; Shen, Jinpeng; Long, Zhang; Li, Zhaoqian; Cui, Xudong; Yang, Guangcheng

2016-01-04

The energy performance of solid energetic materials (Al, Mg, etc.) is typically restricted by a natural passivation layer and the diffusion-limited kinetics between the oxidizer and the metal. In this work, we use polytetrafluoroethylene (PTFE) as the fluorine carrier and the shielding layer to construct a new type of nano-Al based fuels. The PTFE shell not only prevents nano-Al layers from oxidation, but also assists in enhancing the reaction kinetics, greatly improving the stability and reactivity of fuels. An in situ chemical vapor deposition combined with the electrical explosion of wires (EEW) method is used to fabricate core-shell nanostructures. Studies show that by controlling the stoichiometric ratio of the precursors, the morphology of the PTFE shell and the energy performance can be easily tuned. The resultant composites exhibit superior energy output characters than that of their physically mixed Al/PTFE counterparts. This synthetic strategy might provide a general approach to prepare other high-energy fuels (Mg, Si). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and electrochemical performance of surface-modified nano-sized core/shell tin particles for lithium ion batteries

International Nuclear Information System (INIS)

Schmuelling, Guido; Meyer, Hinrich-Wilhelm; Placke, Tobias; Winter, Martin; Oehl, Nikolas; Knipper, Martin; Kolny-Olesiak, Joanna; Plaggenborg, Thorsten; Parisi, Jürgen

2014-01-01

Tin is able to lithiate and delithiate reversibly with a high theoretical specific capacity, which makes it a promising candidate to supersede graphite as the state-of-the-art negative electrode material in lithium ion battery technology. Nevertheless, it still suffers from poor cycling stability and high irreversible capacities. In this contribution, we show the synthesis of three different nano-sized core/shell-type particles with crystalline tin cores and different amorphous surface shells consisting of SnO x and organic polymers. The spherical size and the surface shell can be tailored by adjusting the synthesis temperature and the polymer reagents in the synthesis, respectively. We determine the influence of the surface modifications with respect to the electrochemical performance and characterize the morphology, structure, and thermal properties of the nano-sized tin particles by means of high-resolution transmission electron microscopy, x-ray diffraction, and thermogravimetric analysis. The electrochemical performance is investigated by constant current charge/discharge cycling as well as cyclic voltammetry. (paper)

Design and economic optimization of shell and tube heat exchangers using Artificial Bee Colony (ABC) algorithm

International Nuclear Information System (INIS)

Sencan Sahin, Arzu; Kilic, Bayram; Kilic, Ulas

2011-01-01

Highlights: → Artificial Bee Colony for shell and tube heat exchanger optimization is used. → The total cost is minimized by varying design variables. → This new approach can be applied for optimization of heat exchangers. - Abstract: In this study, a new shell and tube heat exchanger optimization design approach is developed. Artificial Bee Colony (ABC) has been applied to minimize the total cost of the equipment including capital investment and the sum of discounted annual energy expenditures related to pumping of shell and tube heat exchanger by varying various design variables such as tube length, tube outer diameter, pitch size, baffle spacing, etc. Finally, the results are compared to those obtained by literature approaches. The obtained results indicate that Artificial Bee Colony (ABC) algorithm can be successfully applied for optimal design of shell and tube heat exchangers.

Design and economic optimization of shell and tube heat exchangers using Artificial Bee Colony (ABC) algorithm

Energy Technology Data Exchange (ETDEWEB)

Sencan Sahin, Arzu, E-mail: sencan@tef.sdu.edu.tr [Department of Mechanical Education, Technical Education Faculty, Sueleyman Demirel University, 32260 Isparta (Turkey); Kilic, Bayram, E-mail: bayramkilic@hotmail.com [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey); Kilic, Ulas, E-mail: ulaskilic@mehmetakif.edu.tr [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey)

2011-10-15

Highlights: {yields} Artificial Bee Colony for shell and tube heat exchanger optimization is used. {yields} The total cost is minimized by varying design variables. {yields} This new approach can be applied for optimization of heat exchangers. - Abstract: In this study, a new shell and tube heat exchanger optimization design approach is developed. Artificial Bee Colony (ABC) has been applied to minimize the total cost of the equipment including capital investment and the sum of discounted annual energy expenditures related to pumping of shell and tube heat exchanger by varying various design variables such as tube length, tube outer diameter, pitch size, baffle spacing, etc. Finally, the results are compared to those obtained by literature approaches. The obtained results indicate that Artificial Bee Colony (ABC) algorithm can be successfully applied for optimal design of shell and tube heat exchangers.

Structural performance of a multipurpose canister shell for HLNW under normal handling conditions

International Nuclear Information System (INIS)

Ladkany, S.G.; Rajagopalan, R.

1994-01-01

A Multipurpose Canister (MPC) is analyzed for critical stresses that occur during normal handling conditions and accidental scenarios. Linear and Non-linear Finite Element Analysis is performed and the stresses at various critical locations in the MPC and its weldments are studied extensively. Progressive failure analysis of the MPC's groove and fillet welds, is presented. The structural response of the MPC to dynamic lifting loads, to loads resulting from an accidental slippage of a crane cable carrying the MPC, and from the impact between two canisters, is evaluated. Nonlinear structural analysis is used in the evaluation of the local buckling and the ultimate failure phenomena in the shell when the steel is in the strain hardening state during impact. Results make a case for increasing the thickness of the shell and all the welds

Prediction Model of the Outer Radiation Belt Developed by Chungbuk National University

Directory of Open Access Journals (Sweden)

Dae-Kyu Shin

2014-12-01

Full Text Available The Earth’s outer radiation belt often suffers from drastic changes in the electron fluxes. Since the electrons can be a potential threat to satellites, efforts have long been made to model and predict electron flux variations. In this paper, we describe a prediction model for the outer belt electrons that we have recently developed at Chungbuk National University. The model is based on a one-dimensional radial diffusion equation with observationally determined specifications of a few major ingredients in the following way. First, the boundary condition of the outer edge of the outer belt is specified by empirical functions that we determine using the THEMIS satellite observations of energetic electrons near the boundary. Second, the plasmapause locations are specified by empirical functions that we determine using the electron density data of THEMIS. Third, the model incorporates the local acceleration effect by chorus waves into the one-dimensional radial diffusion equation. We determine this chorus acceleration effect by first obtaining an empirical formula of chorus intensity as a function of drift shell parameter L*, incorporating it as a source term in the one-dimensional diffusion equation, and lastly calibrating the term to best agree with observations of a certain interval. We present a comparison of the model run results with and without the chorus acceleration effect, demonstrating that the chorus effect has been incorporated into the model to a reasonable degree.

Partial preservation of the Tentaculites Crotalinus shell from Ponta Grossa Formation (Devonian)

International Nuclear Information System (INIS)

Ciguel, J.H.G.; Roesler, O.

1988-01-01

This paper deals with an analysis of a single specimen of Tentaculites crotalinus SALTER emend. CIGUEL et al. (1984) that present a possible partial preservation of the shell. It comes from an outcrop of the Grossa Formation (Devonian) near Jaguariaiva, State of Parana. The skeletal microstructure of the Tentaculitoidea shell rather poorly Known. Thus, the phylogenetic relationships of these invertebrates still uncertain. Tentaculitids are very common fossils in Devonian Ponta Grossa Formation (Parana Basin) but so far Known only from external and internal moulds. The objective of this study is to demonstrate wheter the layer found in between the internal and external mould is or not a case shell preservation. The chemical composition of this layer and of the external mould was analysed by X rays. X rays difratometry was applied only to the matrix (at the external mould). The structure of the supposed shell remain was studied by binocular stereomicroscope and scanning electron microscope. It revealed a foliate structure due to several paralel to subparalel oriented lamelae, with a chemical composition distinct from the matrix, and some elements possibly mantained from the original shell composition. Thus, a partial preservation of the original shell seems to be the better explanation for this case. This shell would be composed by calcium carbonate disposed in laminar layers, the outer ones being impregnated by Fe and Mn molecules during the diagenetic processes. The skeletal composition and microstructure would suggest a molluscan affinity for the tentaculitida Order. (auThor) [pt

LHCb : Performance, radiation resistance, and expectations of the Outer Tracker straw

CERN Multimedia

Tuning, Niels

2015-01-01

The LHCb experiment is a single arm spectrometer, designed to study CP violation in B-decays at the LHC. It is crucial to accurately and efficiently detect the charged decay particles, in the high-density particle environment of the LHC. For this, the Outer Tracker (OT) was constructed, consisting of 54,000 straw tubes, covering in total an area of 360 m2 of double layers. The detector operated in 2011/2012 under large particle rates, up to 100 kHz/cm per straw in the region closest to the beam. The performance of the OT detector during Run-I of the LHC has been studied in detail, in terms of efficiency, resolution and noise rate. Particular attention is devoted to the radiation hardness of this sensitive gaseous detector, that has shown to suffer from gain loss after mild irradiation in laboratory conditions. During the shutdown period of the LHC, extensive studies have been performed on subtle spatial alignment effects, and real-time calibration procedures have been prepared for run-II. In addition, expect...

Determination of indium content of GaAs/(In,Ga)As/(GaAs) core-shell(-shell) nanowires by x-ray diffraction and nano x-ray fluorescence

Science.gov (United States)

Al Hassan, Ali; Lewis, R. B.; Küpers, H.; Lin, W.-H.; Bahrami, D.; Krause, T.; Salomon, D.; Tahraoui, A.; Hanke, M.; Geelhaar, L.; Pietsch, U.

2018-01-01

We present two complementary approaches to investigate the In content in GaAs/(In,Ga)As/(GaAs) core-shell-(shell) nanowire (NW) heterostructures using synchrotron radiation. The key advantage of our methodology is that NWs are characterized in their as-grown configuration, i.e., perpendicularly standing on a substrate. First, we determine the mean In content of the (In,Ga)As shell by high-resolution x-ray diffraction (XRD) from NW ensembles. In particular, we disentangle the influence of In content and shell thickness on XRD by measuring and analyzing two reflections with diffraction vector parallel and perpendicular to the growth axis, respectively. Second, we study the In distribution within individual NWs by nano x-ray fluorescence. Both the NW (111) basal plane, that is parallel to the surface of the substrate, and the {10-1} sidewall plane were scanned with an incident nanobeam of 50 nm width. We investigate three samples with different nominal In content of the (In,Ga)As shell. In all samples, the average In content of the shell determined by XRD is in good agreement with the nominal value. For a nominal In content of 15%, the In distribution is fairly uniform between all six sidewall facets. In contrast, in NWs with nominally 25% In content, different sidewall facets of the same NW exhibit different In contents. This effect is attributed to shadowing during growth by molecular beam epitaxy. At the same time, along the NW axis the In distribution is still fairly homogeneous. In NWs with 60% nominal In content and no outer GaAs shell, the In content varies significantly both between different sidewall facets and along the NW axis. This fluctuation is explained by the formation of (In,Ga)As mounds that grow simultaneously with a thinner (In,Ga)As shell. The methodology presented here may be applied also to other core-shell NWs with a ternary shell and paves the way to correlating NW structure with functional properties that depend on the as-grown configuration

Protein profiles of hatchery egg shell membrane.

Science.gov (United States)

Rath, N C; Liyanage, R; Makkar, S K; Lay, J O

2016-01-01

Eggshells which consist largely of calcareous outer shell and shell membranes, constitute a significant part of poultry hatchery waste. The shell membranes (ESM) not only contain proteins that originate from egg whites but also from the developing embryos and different contaminants of microbial and environmental origins. As feed supplements, during post hatch growth, the hatchery egg shell membranes (HESM) have shown potential for imparting resistance of chickens to endotoxin stress and exert positive health effects. Considering that these effects are mediated by the bioactive proteins and peptides present in the membrane, the objective of the study was to identify the protein profiles of hatchery eggshell membranes (HESM). Hatchery egg shell membranes were extracted with acidified methanol and a guanidine hydrochloride buffer then subjected to reduction/alkylation, and trypsin digestion. The methanol extract was additionally analyzed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). The tryptic digests were analyzed by liquid chromatography and tandem mass spectrometry (LC-MS-MS) to identify the proteins. Our results showed the presence of several proteins that are inherent and abundant in egg white such as, ovalbumin, ovotransferrin, ovocleidin-116, and lysozyme, and several proteins associated with cytoskeletal, cell signaling, antimicrobial, and catalytic functions involving carbohydrate, nucleic acid, and protein metabolisms. There were some blood derived proteins most likely originating from the embryos and several other proteins identified with different aerobic, anaerobic, gram positive, gram negative, soil, and marine bacterial species some commensals and others zoonotic. The variety of bioactive proteins, particularly the cell signaling and enzymatic proteins along with the diverse microbial proteins, make the HESM suitable for nutritional and biological application to improve post hatch immunity of poultry.

Synthesis of triaxial LiFePO4 nanowire with a VGCF core column and a carbon shell through the electrospinning method.

Science.gov (United States)

Hosono, Eiji; Wang, Yonggang; Kida, Noriyuki; Enomoto, Masaya; Kojima, Norimichi; Okubo, Masashi; Matsuda, Hirofumi; Saito, Yoshiyasu; Kudo, Tetsuichi; Honma, Itaru; Zhou, Haoshen

2010-01-01

A triaxial LiFePO4 nanowire with a multi wall carbon nanotube (VGCF:Vapor-grown carbon fiber) core column and an outer shell of amorphous carbon was successfully synthesized through the electrospinning method. The carbon nanotube core oriented in the direction of the wire played an important role in the conduction of electrons during the charge-discharge process, whereas the outer amorphous carbon shell suppressed the oxidation of Fe2+. An electrode with uniformly dispersed carbon and active materials was easily fabricated via a single process by heating after the electrospinning method is applied. Mossbauer spectroscopy for the nanowire showed a broadening of the line width, indicating a disordered coordination environment of the Fe ion near the surface. The electrospinning method was proven to be suitable for the fabrication of a triaxial nanostructure.

Structural-performance testing of titanium-shell lead-matrix container MM2

Energy Technology Data Exchange (ETDEWEB)

Hosaluk, L. J.; Barrie, J. N.

1992-05-15

This report describes the hydrostatic structural-performance testing of a half-scale, titanium-shell, lead-matrix container (MM2) with a large, simulated volumetric casting defect. Mechancial behaviour of the container is assessed from extensive surface-strain measurements and post-test non-destructive and destructive examinations. Measured strain data are compared briefly with analytical results from a finite-element model of a previous test prototype, MM1, and with data generated by a finite-difference computer code. Finally, procedures are recommended for more detailed analytical modelling. (auth)

Construction of carbon nanoflakes shell on CuO nanowires core as enhanced core/shell arrays anode of lithium ion batteries

International Nuclear Information System (INIS)

Cao, F.; Xia, X.H.; Pan, G.X.; Chen, J.; Zhang, Y.J.

2015-01-01

Highlights: • CuO/C core/shell nanowire arrays are prepared by electro-deposition + ALD method. • Carbon shell is favorable for structural stability. • CuO/C core/shell arrays show enhanced cycle stability and high capacity. - Abstract: Tailored metal oxide/carbon composite structures have attracted great attention due to potential synergistic effects and enhanced properties. In this work, novel CuO/C core/shell nanowire arrays are prepared by the combination of electro-deposition of CuO and atomic-layer-deposition-assisted formation of carbon nanoflakes shell. The CuO nanowires with diameters of ∼200 nm are homogenously coated by carbon nanoflakes shell. When evaluated as anode materials for lithium ion batteries (LIBs), compared to the unmodified CuO nanowire arrays, the CuO/C core/shell nanowire arrays exhibit improved electrochemical performances with higher capacity, better electrochemical reactivity and high-rate capability as well as superior cycling life (610 mAh g"−"1 at 0.5C after 290 cycles). The enhanced electrochemical performance is mainly attributed to the introduction of carbon flake shell in the core/shell nanowire arrays structure, which provides higher active material-electrolyte contact area, improved electrical conductivity, and better accommodation of volume change. The proposed method provides a new way for fabrication of high-performance metal oxides anodes of LIBs.

Collapse analysis of toroidal shell

International Nuclear Information System (INIS)

Pomares, R.J.

1990-01-01

This paper describes a study performed to determine the collapse characteristics of a toroidal shell using finite element method (FEM) analysis. The study also included free drop testing of a quarter scale prototype to verify the analytical results. The full sized toroidal shell has a 24-inch toroidal diameter with a 24-inch tubal diameter. The shell material is type 304 strainless steel. The toroidal shell is part of the GE Model 2000 transportation packaging, and acts as an energy absorbing device. The analyses performed were on a full sized and quarter scaled models. The finite element program used in all analyses was the LIBRA code. The analytical procedure used both the elasto-plastic and large displacement options within the code. The loading applied in the analyses corresponded to an impact of an infinite rigid plane oriented normal to the drop direction vector. The application of the loading continued incrementally until the work performed by the deforming structure equalled the kinetic energy developed in the free fall. The comparison of analysis and test results showed a good correlation

Ionic bonding of lanthanides, as influenced by d- and f-atomic orbitals, by core-shells and by relativity.

Science.gov (United States)

Ji, Wen-Xin; Xu, Wei; Schwarz, W H Eugen; Wang, Shu-Guang

2015-03-15

Lanthanide trihalide molecules LnX3 (X = F, Cl, Br, I) were quantum chemically investigated, in particular detail for Ln = Lu (lutetium). We applied density functional theory (DFT) at the nonrelativistic and scalar and SO-coupled relativistic levels, and also the ab initio coupled cluster approach. The chemically active electron shells of the lanthanide atoms comprise the 5d and 6s (and 6p) valence atomic orbitals (AO) and also the filled inner 4f semivalence and outer 5p semicore shells. Four different frozen-core approximations for Lu were compared: the (1s(2) -4d(10) ) [Pd] medium core, the [Pd+5s(2) 5p(6) = Xe] and [Pd+4f(14) ] large cores, and the [Pd+4f(14) +5s(2) 5p(6) ] very large core. The errors of LuX bonding are more serious on freezing the 5p(6) shell than the 4f(14) shell, more serious upon core-freezing than on the effective-core-potential approximation. The LnX distances correlate linearly with the AO radii of the ionic outer shells, Ln(3+) -5p(6) and X(-) -np(6) , characteristic for dominantly ionic Ln(3+) -X(-) binding. The heavier halogen atoms also bind covalently with the Ln-5d shell. Scalar relativistic effects contract and destabilize the LuX bonds, spin orbit coupling hardly affects the geometries but the bond energies, owing to SO effects in the free atoms. The relativistic changes of bond energy BE, bond length Re , bond force k, and bond stretching frequency vs do not follow the simple rules of Badger and Gordy (Re ∼BE∼k∼vs ). The so-called degeneracy-driven covalence, meaning strong mixing of accidentally near-degenerate, nearly nonoverlapping AOs without BE contribution is critically discussed. © 2015 Wiley Periodicals, Inc.

Effects of radial distribution of entropy diffusivity on critical modes of anelastic thermal convection in rotating spherical shells

Science.gov (United States)

Sasaki, Youhei; Takehiro, Shin-ichi; Ishiwatari, Masaki; Yamada, Michio

2018-03-01

Linear stability analysis of anelastic thermal convection in a rotating spherical shell with entropy diffusivities varying in the radial direction is performed. The structures of critical convection are obtained in the cases of four different radial distributions of entropy diffusivity; (1) κ is constant, (2) κT0 is constant, (3) κρ0 is constant, and (4) κρ0T0 is constant, where κ is the entropy diffusivity, T0 is the temperature of basic state, and ρ0 is the density of basic state, respectively. The ratio of inner and outer radii, the Prandtl number, the polytropic index, and the density ratio are 0.35, 1, 2, and 5, respectively. The value of the Ekman number is 10-3 or 10-5 . In the case of (1), where the setup is same as that of the anelastic dynamo benchmark (Jones et al., 2011), the structure of critical convection is concentrated near the outer boundary of the spherical shell around the equator. However, in the cases of (2), (3) and (4), the convection columns attach the inner boundary of the spherical shell. A rapidly rotating annulus model for anelastic systems is developed by assuming that convection structure is uniform in the axial direction taking into account the strong effect of Coriolis force. The annulus model well explains the characteristics of critical convection obtained numerically, such as critical azimuthal wavenumber, frequency, Rayleigh number, and the cylindrically radial location of convection columns. The radial distribution of entropy diffusivity, or more generally, diffusion properties in the entropy equation, is important for convection structure, because it determines the distribution of radial basic entropy gradient which is crucial for location of convection columns.

Electrochemical Properties of LLTO/Fluoropolymer-Shell Cellulose-Core Fibrous Membrane for Separator of High Performance Lithium-Ion Battery

Science.gov (United States)

Huang, Fenglin; Liu, Wenting; Li, Peiying; Ning, Jinxia; Wei, Qufu

2016-01-01

A superfine Li0.33La0.557TiO3 (LLTO, 69.4 nm) was successfully synthesized by a facile solvent-thermal method to enhance the electrochemical properties of the lithium-ion battery separator. Co-axial nanofiber of cellulose and Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was prepared by a co-axial electrospinning technique, in which the shell material was PVDF-HFP and the core was cellulose. LLTO superfine nanoparticles were incorporated into the shell of the PVDF-HFP. The core–shell composite nanofibrous membrane showed good wettability (16.5°, contact angle), high porosity (69.77%), and super electrolyte compatibility (497%, electrolyte uptake). It had a higher ionic conductivity (13.897 mS·cm−1) than those of pure polymer fibrous membrane and commercial separator. In addition, the rate capability (155.56 mAh·g−1) was also superior to the compared separator. These excellent performances endowed LLTO composite nanofibrous membrane as a promising separator for high-performance lithium-ion batteries. PMID:28787873

Effects of spray axis incident angle on heat transfer performance of rhombus-pitch shell-and-tube interior spray evaporator

International Nuclear Information System (INIS)

Lin, Ru-Li; Chang, Tong-Bou; Liang, Chih-Chang

2012-01-01

An interior spray method is proposed for enhancing the heat transfer performance of a compact rhombus-pitch shell-and-tube spray evaporator. The experimental results show that the shell-side heat transfer coefficient obtained using the proposed spray method is significantly higher than that achieved in a conventional flooded-type evaporator. Four different spray axis incident angles (0 .deg., 45 .deg., 60 .deg. and 75 .deg.) are tested in order to investigate the effect of the spray inclination angle on the heat transfer performance of the spray evaporator system. It is shown that the optimal heat transfer performance is obtained using a spray axis incident angle of 60 .deg.

Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography

Energy Technology Data Exchange (ETDEWEB)

Saini, Gaurav; Jensen, David S.; Wiest, Landon A.; Vail, Michael A.; Dadson, Andrew; Lee, Milton L.; Shutthanandan, V.; Linford, Matthew R.

2010-06-01

We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 μm) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 μm), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

Core-shell diamond as a support for solid-phase extraction and high-performance liquid chromatography.

Science.gov (United States)

Saini, Gaurav; Jensen, David S; Wiest, Landon A; Vail, Michael A; Dadson, Andrew; Lee, Milton L; Shutthanandan, V; Linford, Matthew R

2010-06-01

We report the formation of core-shell diamond particles for solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO(2) surfaces, which were characterized by scanning electron microscopy (SEM), Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer-Emmett-Teller (BET) surface area and pore size measurements. Larger (ca. 50 microm) core-shell diamond particles have much higher surface areas and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 microm), normal and reversed-phase, core-shell diamond particles have been used for HPLC, with 36,300 plates/m for mesitylene in a separation of benzene and alkyl benzenes and 54,800 plates/m for diazinon in a similar separation of two pesticides on a C(18) adsorbent.

Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography

International Nuclear Information System (INIS)

Saini, Gaurav; Jensen, David S.; Wiest, Landon A.; Vail, Michael A.; Dadson, Andrew; Lee, Milton L.; Shutthanandan, V.; Linford, Matthew R.

2010-01-01

We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 ?m) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 ?m), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

Improving the electrode performance of Ge through Ge@C core-shell nanoparticles and graphene networks.

Science.gov (United States)

Xue, Ding-Jiang; Xin, Sen; Yan, Yang; Jiang, Ke-Cheng; Yin, Ya-Xia; Guo, Yu-Guo; Wan, Li-Jun

2012-02-08

Germanium is a promising high-capacity anode material for lithium ion batteries, but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. A double protection strategy to improve the electrode performance of Ge through the use of Ge@C core-shell nanostructures and reduced graphene oxide (RGO) networks has been developed. The as-synthesized Ge@C/RGO nanocomposite showed excellent cycling performance and rate capability in comparison with Ge@C nanoparticles when used as an anode material for Li ion batteries, which can be attributed to the electronically conductive and elastic RGO networks in addition to the carbon shells and small particle sizes of Ge. The strategy is simple yet very effective, and because of its versatility, it may be extended to other high-capacity electrode materials with large volume variations and low electrical conductivities.

Development of hydrogel TentaGel shell-core beads for ultrahigh throughput solution-phase screening of encoded OBOC combinatorial small molecule libraries.

Science.gov (United States)

Baek, Hyoung Gee; Liu, Ruiwu; Lam, Kit S

2009-01-01

The one-bead one-compound (OBOC) combinatorial library method enables the rapid generation and screening of millions of discrete chemical compounds on beads. Most of the OBOC screening methods require the library compounds to remain tethered to the bead during screening process. Methods have also been developed to release library compounds from immobilized beads for in situ solution phase or "lawn" assays. However, this latter approach, while extremely powerful, is severely limited by the lack of suitable solid supports for such assays. Here, we report on the development of a novel hydrogel TentaGel shell-core (HTSC) bead in which hydrogel is grafted onto the polystyrene-based TentaGel (TG) bead as an outer shell (5-80 mum thick) via free radical surface-initiated polymerization. This novel shell-core bilayer resin enables the preparation of encoded OBOC combinatorial small molecule libraries, such that the library compounds reside on the highly hydrophilic outer layer and the coding tags reside in the polystyrene-based TG core. Using fluorescein as a model small molecule compound, we have demonstrated that fluorescein molecules that have been linked covalently to the hydrogel shell via a disulfide bond could readily diffuse out of the hydrogel layer into the bead surrounding after reduction with dithiothreitol. In contrast, under identical condition, the released fluorescein molecules remained bound to unmodified TG bead. We have prepared an encoded OBOC small molecule library on the novel shell-core beads and demonstrated that the beads can be readily decoded.

Imaging Shock Fronts in the Outer Ejecta of Eta Carinae

Science.gov (United States)

Smith, Nathan

2017-08-01

Although Eta Car has been imaged many times with HST to monitor the central star and the bright Homunculus Nebula, we propose the first WFC3 imaging of Eta Car to study the more extended Outer Ejecta from previous eruptions. WFC3 has two key filters that have not been used before to image Eta Car, which will provide critical physical information about its eruptive history: (1) F280N with WFC3/UVIS will produce the first Mg II 2800 image of Eta Car, the sharpest image of its complex Outer Ejecta, and will unambiguously trace shock fronts, and (2) F126N with WFC3/IR will sample [Fe II] 12567 arising in the densest post-shock gas. Eta Car is surrounded by a bright, soft X-ray shell seen in Chandra images, which arises from the fastest 1840s ejecta overtaking slower older material. Our recent proper motion measurements show that the outer knots were ejected in two outbursts several hundred years before the 1840s eruption, and spectroscopy of light echoes has recently revealed extremely fast ejecta during the 1840s that indicate an explosive event. Were those previous eruptions explosive as well? If so, were they as energetic, did they also have such fast ejecta, and did they have the same geometry? The structure and excitation of the Outer Ejecta hold unique clues for reconstructing Eta Car's violent mass loss history. The locations of shock fronts in circumstellar material provide critical information, because they identify past discontinuities in the mass loss. This is one of the only ways to investigate the long term (i.e. centuries) evolution and duty cycle of eruptive mass loss in the most massive stars.

High ink absorption performance of inkjet printing based on SiO2@Al13 core-shell composites

Science.gov (United States)

Chen, YiFan; Jiang, Bo; Liu, Li; Du, Yunzhe; Zhang, Tong; Zhao, LiWei; Huang, YuDong

2018-04-01

The increasing growth of the inkjet market makes the inkjet printing more necessary. A composite material based on core-shell structure has been developed and applied to prepare inkjet printing layer. In this contribution, the ink printing record layers based on SiO2@Al13 core-shell composite was elaborated. The prepared core-shell composite materials were characterized by X-ray photoelectron spectroscopy (XPS), zeta potential, X-ray diffraction (XRD), scanning electron microscopy (SEM). The results proved the presence of electrostatic adsorption between SiO2 molecules and Al13 molecules with the formation of the well-dispersed system. In addition, based on the adsorption and the liquid permeability analysis, SiO2@Al13 ink printing record layer achieved a relatively high ink uptake (2.5 gmm-1) and permeability (87%), respectively. The smoothness and glossiness of SiO2@Al13 record layers were higher than SiO2 record layers. The core-shell structure facilitated the dispersion of the silica, thereby improved its ink absorption performance and made the clear printed image. Thus, the proposed procedure based on SiO2@Al13 core-shell structure of dye particles could be applied as a promising strategy for inkjet printing.

Controlled Synthesis of Au@AgAu Yolk-Shell Cuboctahedra with Well-Defined Facets.

Science.gov (United States)

Londono-Calderon, Alejandra; Bahena, Daniel; Yacaman, Miguel J

2016-08-02

The synthesis of Au@AgAu yolk-shell cuboctahedra nanoparticles formed by galvanic replacement in a seed-mediated method is described. Initially, single-crystal Au seeds are used for the formation of Au@Ag core-shell nanocubes, which serve as the template material for the deposition of an external Au layer. The well-controlled synthesis yields the formation of cuboctahedra nanoparticles with smooth inner and outer Au/Ag surfaces. The deposition/oxidation process is described to understand the formation of cuboctahedra and octahedra nanoparticles. The Au core maintains the initial morphology of the seed and remains static at the center of the yolk-shell because of residual Ag. Structural analysis of the shell indicates intrinsic stacking faults (SFs) near the surface. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) compositional analysis show an Au-Ag nonordered alloy forming the shell. The three-dimensional structure of the nanoparticles presented open facets on the [111] as observed by electron tomography SIRT reconstruction over a stack of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The geometrical model was validated by analyzing the direction of streaks in coherent nanobeam diffraction (NBD). The catalytic activity was evaluated using a model reaction based on the reduction of 4-nitrophenol (4-NTP) by NaBH4 in the presence of Au@AgAu yolk-shell nanoparticles.

Software alignment of the LHCb Outer Tracker chambers

Energy Technology Data Exchange (ETDEWEB)

Deissenroth, Marc

2010-04-21

This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 {mu}m) for the translational degrees of freedom and of O(10{sup -2} - 10{sup -1} mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within {proportional_to} 90 {mu}m. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

Software alignment of the LHCb Outer Tracker chambers

International Nuclear Information System (INIS)

Deissenroth, Marc

2010-01-01

This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 μm) for the translational degrees of freedom and of O(10 -2 - 10 -1 mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within ∝ 90 μm. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

Electrochemical capacitive performances of nanoporous carbon derived from sunflower seed shell

Energy Technology Data Exchange (ETDEWEB)

Li, X; Xing, W.; Zhuo, S.; Zhou, J. [Shandong Univ. of Technology, Zibo (China). School of Chemical Engineering

2010-07-01

Electrochemical double-layer capacitances (EDLCs) are used in applications were high power density and long cycle life are required. Nanoporous materials are typically used to prepare EDLC electrodes due to their high surface area, good physicochemical stability, and high conductivity. In this study, nanoporous carbon materials were prepared from sunflower seed shells and used as an electrode material for an EDLC. The surface and structural properties of the carbon materials were analyzed using N{sub 2} adsorption and scanning electron microscopy (SEM) techniques. The study showed that AC-X-Y carbons prepared using the impregnation-activation process had a better capacitive behaviour and higher capacitance retention ratio at fast charge-discharge rates than carbons made using the carbonization-activation process. The improved electrochemical performance of the carbons was attributed to the abundant macroscopic pores and decreased interior micropore surface. The specific capacitances of the carbon was approximately twice that of a hard-templated mesoporous carbon in all current densities ranging from 0.25 to 10 A per g. Results indicated that sunflower seed shells can be used to prepare EDLCs. 2 refs., 1 fig.

Thermoluminescence analysis of irradiated oyster shells

International Nuclear Information System (INIS)

Cruz-Zaragoza, E.; Marcazzó, J.; Della Monaca, S.; Boniglia, C.; Gargiulo, R.; Bortolin, E.

2012-01-01

This paper reports the thermoluminescence (TL) analysis performed on the oyster shells powder. TL response of 60 Co gamma-rays irradiated samples were studied in the range from 80 Gy to 8 kGy doses. TL signal of irradiated shell powder was higher as compared to the unirradiated control samples, which allowed to identify the irradiated oysters. Results show that the oyster shells have good TL properties and can be useful for the identification of irradiated seafood as well as for the evaluation of the treatment dose. - Highlights: ► TL properties of irradiated oyster shell powder were studied. ► The SEM analysis shows that several elements are present in oyster shell powder. ► Calcite is the main component in the samples and β-calcite is also present. ► Following the European Standard EN 1788, the irradiated oyster can be identified. ► Determination of absorbed dose is possible by performing a preheat treatment.

Electrochemical performance and structure evolution of core-shell nano-ring α-Fe{sub 2}O{sub 3}@Carbon anodes for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Sun, Yan-Hui, E-mail: sunyanhui0102@163.com; Liu, Shan; Zhou, Feng-Chen; Nan, Jun-Min

2016-12-30

Core-shell nano-ring α-Fe{sub 2}O{sub 3}@Carbon (CSNR) composites with different carbon content (CSNR-5%C and CSNR-13%C) are synthesized using a hydrothermal method by controlling different amounts of glucose and α-Fe{sub 2}O{sub 3} nano-rings with further annealing. The CSNR electrodes exhibit much improved specific capacity, cycling stability and rate capability compared with that of bare nano-ring α-Fe{sub 2}O{sub 3} (BNR), which is attributed to the core-shell nano-ring structure of CSNR. The carbon shell in the inner and outer surface of CSNR composite can increase electron conductivity of the electrode and inhibit the volume change of α-Fe{sub 2}O{sub 3} during discharge/charge processes, and the nano-ring structure of CSNR can buffer the volume change too. The CSNR-5%C electrode shows super high initial discharge/charge capacities of 1570/1220 mAh g{sup −1} and retains 920/897 mAh g{sup −1} after 200 cycles at 500 mA g{sup −1} (0.5C). Even at 2000 mA g{sup −1} (2C), the electrode delivers the initial capacities of 1400/900 mAh g{sup −1}, and still maintains 630/610 mAh g{sup −1} after 200 cycles. The core-shell nano-rings opened during cycling and rebuilt a new flower-like structure consisting of α-Fe{sub 2}O{sub 3}@Carbon nano-sheets. The space among the nano-sheet networks can further buffer the volume expansion of α-Fe{sub 2}O{sub 3} and facilitate the transportation of electrons and Li{sup +} ions during the charge/discharge processes, which increases the capacity and rate capability of the electrode. It is the first time that the evolution of core-shell α-Fe{sub 2}O{sub 3}@Carbon changing to flower-like networks during lithiation/de-lithiation has been reported.

Research on soundproof properties of cylindrical shells of generalized phononic crystals

Science.gov (United States)

Liu, Ru; Shu, Haisheng; Wang, Xingguo

2017-04-01

Based on the previous studies, the concept of generalized phononic crystals (GPCs) is further introduced into the cylindrical shell structures in this paper. And a type of cylindrical shells of generalized phononic crystals (CS-GPCs) is constructed, the structural field and acoustic-structural coupled field of the composite cylindrical shells are examined respectively. For the structural field, the transfer matrix method of mechanical state vector is adopted to build the transfer matrix of radial waves propagating from inside to outside. For the acoustic-structural coupled field, the expressions of the acoustic transmission/reflection coefficients and the sound insulation of acoustic waves with the excitation of center line sound source are set up. And the acoustic transmission coefficient and the frequency response of sound insulation in this mode were numerical calculated. Furthermore, the theoretical analysis results are verified by using the method of combining the numerical calculation and finite element simulation. Finally, the effects of inner and outer fluid parameters on the transmission/reflection coefficients of CS-GPCs are analyzed in detail.

Performance demonstration experience for reactor pressure vessel shell ultrasonic testing

International Nuclear Information System (INIS)

Zado, V.

1998-01-01

The most ultrasonic testing techniques used by many vendors for pressurized water reactor (PWR) examinations were based on American Society of Mechanical Engineers 'Boiler and Pressurized Vessel Code' (ASME B and PV Code) Sections XI and V. The Addenda of ASME B and PV Code Section XI, Edition 1989 introduced Appendix VIII - 'Performance Demonstration for Ultrasonic Examination Systems'. In an effort to increase confidence in performance of ultrasonic testing of the operating nuclear power plants in United States, the ultrasonic testing performance demonstration examination of reactor vessel welds is performed in accordance with Performance Demonstration Initiative (PDI) program which is based on ASME Code Section XI, Appendix VIII requirements. This article provides information regarding extensive qualification preparation works performed prior EPRI guided performance demonstration exam of reactor vessel shell welds accomplished in January 1997 for the scope of Appendix VIII, Supplements IV and VI. Additionally, an overview of the procedures based on requirements of ASME Code Section XI and V in comparison to procedure prepared for Appendix VIII examination is given and discussed. The samples of ultrasonic signals obtained from artificial flaws implanted in vessel material are presented and results of ultrasonic testing are compared to actual flaw sizes. (author)

Artificially evolved functional shell morphology of burrowing bivalves

DEFF Research Database (Denmark)

Germann, D. P.; Schatz, W.; Hotz, Peter Eggenberger

2014-01-01

The morphological evolution of bivalves is documented by a rich fossil record. It is believed that the shell shape and surface sculpture play an important role for the burrowing performance of endobenthic species. While detailed morphometric studies of bivalve shells have been done...... dimensional (3D) objects, the first ever artificial evolution of a physical bivalve shell was performed. The result was a vertically flattened shell occupying only the top sediment layers. Insufficient control of the sediment was the major limitation of the setup and restricted the significance of the results...

Hylleraas-like functions with the correct cusp conditions: K-shell electrons for the neutral atoms

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, K.V. [Universidad Nacional del Sur, 8000 Bahia Blanca and Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina)], E-mail: krodri@criba.edu.ar; Gasaneo, G. [Universidad Nacional del Sur, 8000 Bahia Blanca and Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Mitnik, D.M.; Miraglia, J.E. [Instituto de Astronomia y Fisica del Espacio and Universidad de Buenos Aires (Argentina)

2007-10-15

We present simple correlated wavefunctions for the two K-shell electrons of neutral atoms. A variational method was chosen to calculate the mean energy of the ground state, in which the electrons are subject to a local Hartree potential representing the presence of the outer shell electrons. The functions are constructed in terms of exponential and power series, where special care has been taken in order to fulfill the exact behavior at the electron-electron and electron-nucleus coalescence points (Kato cusp conditions). Global properties, such as the energies and virial coefficients, as well as local properties, such as spatial mean values, are also analyzed.

Chemical insights into the roles of nanowire cores on the growth and supercapacitor performances of Ni-Co-O/Ni(OH)₂ core/shell electrodes.

Science.gov (United States)

Yin, Xuesong; Tang, Chunhua; Zhang, Liuyang; Yu, Zhi Gen; Gong, Hao

2016-02-09

Nanostructured core/shell electrodes have been experimentally demonstrated promising for high-performance electrochemical energy storage devices. However, chemical insights into the significant roles of nanowire cores on the growth of shells and their supercapacitor behaviors still remain as a research shortfall. In this work, by substituting 1/3 cobalt in the Co3O4 nanowire core with nickel, a 61% enhancement of the specific mass-loading of the Ni(OH)2 shell, a tremendous 93% increase of the volumetric capacitance and a superior cyclability were achieved in a novel NiCo2O4/Ni(OH)2 core/shell electrode in contrast to a Co3O4/Ni(OH)2 one. A comparative study suggested that not only the growth of Ni(OH)2 shells but also the contribution of cores were attributed to the overall performances. Importantly, their chemical origins were revealed through a theoretical simulation of the core/shell interfacial energy changes. Besides, asymmetric supercapacitor devices and applications were also explored. The scientific clues and practical potentials obtained in this work are helpful for the design and analysis of alternative core/shell electrode materials.

Lessons Not Learned. The Other Shell Report 2004

International Nuclear Information System (INIS)

Harden, M.; Walker, N.; Griffiths, H.; Verweij, M.

2005-06-01

The third alternative Shell Corporate Social Responsibility (CSR) report is presented on behalf of several of the many communities that live on Shell's 'fencelines', next to Shell's refineries, depots and pipelines. This 2004 report builds on reports of the past two years 'Failing the Challenge', (2002) and 'Behind the Shine' (2003) which chronicled Shell's impacts around the world. It gives critical updates of Shell's performance over the past year

Structure and expression of an unusually acidic matrix protein of pearl oyster shells

International Nuclear Information System (INIS)

Tsukamoto, Daiki; Sarashina, Isao; Endo, Kazuyoshi

2004-01-01

We report identification and characterization of the unusually acidic molluscan shell matrix protein Aspein, which may have important roles in calcium carbonate biomineralization. The Aspein gene (aspein) encodes a sequence of 413 amino acids, including a high proportion of Asp (60.4%), Gly (16.0%), and Ser (13.2%), and the predicted isoelectric point is 1.45; this is the most acidic of all the molluscan shell matrix proteins sequenced so far, or probably even of all known proteins on earth. The main body of Aspein is occupied by (Asp) 2-10 sequences punctuated with Ser-Gly dipeptides. RT-PCR demonstrated that the transcript of aspein is expressed at the outer edge of the mantle, corresponding to the calcitic prismatic layer, but not at the inner part of the mantle, corresponding to the aragonitic nacreous layer. Our findings and previous in vitro experiments taken together suggest that Aspein is responsible for directed formation of calcite in the shell of the pearl oyster Pinctada fucata

Multishelled NiO Hollow Microspheres for High-performance Supercapacitors with Ultrahigh Energy Density and Robust Cycle Life

Science.gov (United States)

Qi, Xinhong; Zheng, Wenji; Li, Xiangcun; He, Gaohong

2016-09-01

Multishelled NiO hollow microspheres for high-performance supercapacitors have been prepared and the formation mechanism has been investigated. By using resin microspheres to absorb Ni2+ and subsequent proper calcinations, the shell numbers, shell spacing and exterior shell structure were facilely controlled via varying synthetic parameters. Particularly, the exterior shell structure that accurately associated with the ion transfer is finely controlled by forming a single shell or closed exterior double-shells. Among multishelled NiO hollow microspheres, the triple-shelled NiO with an outer single-shelled microspheres show a remarkable capacity of 1280 F g-1 at 1 A g-1, and still keep a high value of 704 F g-1 even at 20 A g-1. The outstanding performances are attributed to its fast ion/electron transfer, high specific surface area and large shell space. The specific capacitance gradually increases to 108% of its initial value after 2500 cycles, demonstrating its high stability. Importantly, the 3S-NiO-HMS//RGO@Fe3O4 asymmetric supercapacitor shows an ultrahigh energy density of 51.0 Wh kg-1 at a power density of 800 W kg-1, and 78.8% capacitance retention after 10,000 cycles. Furthermore, multishelled NiO can be transferred into multishelled Ni microspheres with high-efficient H2 generation rate of 598.5 mL H2 min-1 g-1Ni for catalytic hydrolysis of NH3BH3 (AB).

Enhanced Performance of Photoelectrochemical Water Splitting with ITO@α-Fe2O3 Core-Shell Nanowire Array as Photoanode.

Science.gov (United States)

Yang, Jie; Bao, Chunxiong; Yu, Tao; Hu, Yingfei; Luo, Wenjun; Zhu, Weidong; Fu, Gao; Li, Zhaosheng; Gao, Hao; Li, Faming; Zou, Zhigang

2015-12-09

Hematite (α-Fe2O3) is one of the most promising candidates for photoelectrodes in photoelectrochemical water splitting system. However, the low visible light absorption coefficient and short hole diffusion length of pure α-Fe2O3 limits the performance of α-Fe2O3 photoelectrodes in water splitting. Herein, to overcome these drawbacks, single-crystalline tin-doped indium oxide (ITO) nanowire core and α-Fe2O3 nanocrystal shell (ITO@α-Fe2O3) electrodes were fabricated by covering the chemical vapor deposited ITO nanowire array with compact thin α-Fe2O3 nanocrystal film using chemical bath deposition (CBD) method. The J-V curves and IPCE of ITO@α-Fe2O3 core-shell nanowire array electrode showed nearly twice as high performance as those of the α-Fe2O3 on planar Pt-coated silicon wafers (Pt/Si) and on planar ITO substrates, which was considered to be attributed to more efficient hole collection and more loading of α-Fe2O3 nanocrystals in the core-shell structure than planar structure. Electrochemical impedance spectra (EIS) characterization demonstrated a low interface resistance between α-Fe2O3 and ITO nanowire arrays, which benefits from the well contact between the core and shell. The stability test indicated that the prepared ITO@α-Fe2O3 core-shell nanowire array electrode was stable under AM1.5 illumination during the test period of 40,000 s.

Catalyst-free combined synthesis of Zn/ZnO core/shell hollow microspheres and metallic Zn microparticles by thermal evaporation and condensation route

Energy Technology Data Exchange (ETDEWEB)

Khan, Waheed S. [Research Centre of Materials Science, Beijing Institute of Technology, Beijing 100081 (China); Cao Chuanbao, E-mail: cbcao@bit.edu.c [Research Centre of Materials Science, Beijing Institute of Technology, Beijing 100081 (China); Nabi, Ghulam; Yao Ruimin; Bhatti, Sajjad H. [Research Centre of Materials Science, Beijing Institute of Technology, Beijing 100081 (China)

2010-09-17

observed to have single crystalline ZnO pointed rods in extremely low density grown on the outer shell. The structural, compositional and morphological characterization of the products obtained on the substrates were performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). A vapor-liquid-solid (VLS) process based growth mechanism was proposed for the formation of Zn/ZnO core/shell microspheres with hollow interior. The optical properties of Zn/ZnO core/shell microspheres were investigated by measuring the photoluminescence (PL) spectra at room temperature (RT). Two very strong emission bands were observed at 373 and 469 nm in the ultraviolet and visible regions respectively under excitation wavelength of 325 nm. Also the effect of the various excitation wavelengths on the PL behaviour was studied at room temperature. PL studies of Zn/ZnO core/shell microspheres show the promise of the material for applications in UV and blue light optical devices.

Oscillations of the Outer Boundary of the Outer Radiation Belt During Sawtooth Oscillations

Directory of Open Access Journals (Sweden)

Jae-Hun Kim

2006-09-01

Full Text Available We report three sawtooth oscillation events observed at geosynchronous orbit where we find quasi-periodic (every 2-3 hours sudden flux increases followed by slow flux decreases at the energy levels of ˜50-400 keV. For these three sawtooth events, we have examined variations of the outer boundary of the outer radiation belt. In order to determine L values of the outer boundary, we have used data of relativistic electron flux observed by the SAMPEX satellite. We find that the outer boundary of the outer radiation belt oscillates periodically being consistent with sawtooth oscillation phases. Specifically, the outer boundary of the outer radiation belt expands (namely, the boundary L value increases following the sawtooth particle flux enhancement of each tooth, and then contracts (namely, the boundary L value decreases while the sawtooth flux decreases gradually until the next flux enhancement. On the other hand, it is repeatedly seen that the asymmetry of the magnetic field intensity between dayside and nightside decreases (increases due to the dipolarization (the stretching on the nightside as the sawtooth flux increases (decreases. This implies that the periodic magnetic field variations during the sawtooth oscillations are likely responsible for the expansion-contraction oscillations of the outer boundary of the outer radiation belt.

Fabrication of In2O3@In2S3 core-shell nanocubes for enhanced photoelectrochemical performance

Science.gov (United States)

Li, Haohua; Chen, Cong; Huang, Xinyou; Leng, Yang; Hou, Mengnan; Xiao, Xiaogu; Bao, Jie; You, Jiali; Zhang, Wenwen; Wang, Yukun; Song, Juan; Wang, Yaping; Liu, Qinqin; Hope, Gregory A.

2014-02-01

Herein, we report the facile synthesis of In2O3@In2S3 core-shell nanocubes and their improved photoelectrochemical property. In2O3@In2S3 core-shell nanocubes are grown on a F-doped SnO2 (FTO) glass substrate by a two-step process, which involves the electrodeposition of In2O3 nanocubes and a subsequent ion-exchange treatment. The improved light-harvesting ability and the suitable band alignment of the In2O3@In2S3 core-shell nanocubes generate a remarkable photocurrent density of 6.19 mA cm-2 (at 0 V vs. Ag/AgCl), which is substantially higher than the pristine In2O3 nanocubes. These results provide a new insight into the design of a high-performance photoanode for photoelectrochemical water splitting.

Electrochemical Properties of LLTO/Fluoropolymer-Shell Cellulose-Core Fibrous Membrane for Separator of High Performance Lithium-Ion Battery

Directory of Open Access Journals (Sweden)

Fenglin Huang

2016-01-01

Full Text Available A superfine Li0.33La0.557TiO3 (LLTO, 69.4 nm was successfully synthesized by a facile solvent-thermal method to enhance the electrochemical properties of the lithium-ion battery separator. Co-axial nanofiber of cellulose and Poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP was prepared by a co-axial electrospinning technique, in which the shell material was PVDF-HFP and the core was cellulose. LLTO superfine nanoparticles were incorporated into the shell of the PVDF-HFP. The core–shell composite nanofibrous membrane showed good wettability (16.5°, contact angle, high porosity (69.77%, and super electrolyte compatibility (497%, electrolyte uptake. It had a higher ionic conductivity (13.897 mS·cm−1 than those of pure polymer fibrous membrane and commercial separator. In addition, the rate capability (155.56 mAh·g−1 was also superior to the compared separator. These excellent performances endowed LLTO composite nanofibrous membrane as a promising separator for high-performance lithium-ion batteries.

The analysis of PO2 difference between air space and arterialized blood in chicken eggs with respect to widely altered shell conductance.

Science.gov (United States)

Wakayama, H; Tazawa, H

1988-01-01

The gas exchange of chicken eggs takes place by molecular diffusion. The diffusion barrier between ambient atmosphere and erythrocyte hemoglobin of the gas exchanger (the vascularized chorioallantoic membrane) is conveniently divided into two parts by the air space in the fibrous shell membranes; i.e., the outer barrier (mainly the porous eggshell) and the inner barrier (the chorioallantoic membrane and the chemical reaction with hemoglobin). In contrast to the alveolar-arterial Po2 difference in vertebrate lungs, the difference of Po2 between the air space and the arterialized blood in the allantoic vein (delta PAo2.Pao2) is large in chick embryos. The present study analyzed the delta PAo2.Pao2 in relation to the diffusing capacity of the chorioallantoic membrane (inner barrier) and physiological shunt in the allantoic circulation with respect to widely altered diffusive conductance of the shell (outer barrier). The shell diffusive conductance (Go2) was altered of the beginning of incubation, and the O2 consumption (Mo2) was measured on day 16. The Mo2 increased hyperbolically with increasing Go2, reached a maximum at control values of Go2 and decreased with further increases in Go2. From Go2 and Mo2, the air space Po2 was determined. The delta PAo2.Pao2 was increased in eggs with augmented Go2 (from about 50 torr in control eggs to 70 torr in conductance-increased eggs). The diffusing capacity and allantoic shunt which produce a given delta PAo2.Pao2 were estimated employing a microcomputer performing the Bohr integration procedure so that a calculated Pao2 agreed with the measured Pao2. The allantoic shunt is not more than 20%; 10% is likely. The diffusing capacity becomes maximum in intact control eggs and is decreased at both lowered and augmented Go2. At lowered Go2, diffusion limitation is responsible for about 90% of delta Pao2.Pao2 even in the presence of a 10% shunt. The diffusion limitation to blood oxygenation decreases as Go2 increases, but it is still

Hollow Pd/MOF Nanosphere with Double Shells as Multifunctional Catalyst for Hydrogenation Reaction.

Science.gov (United States)

Wan, Mingming; Zhang, Xinlu; Li, Meiyan; Chen, Bo; Yin, Jie; Jin, Haichao; Lin, Lin; Chen, Chao; Zhang, Ning

2017-10-01

A new type of hollow nanostructure featured double metal-organic frameworks shells with metal nanoparticles (MNPs) is designed and fabricated by the methods of ship in a bottle and bottle around the ship. The nanostructure material, hereinafter denoted as Void@HKUST-1/Pd@ZIF-8, is confirmed by the analyses of photograph, transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction, inductively coupled plasma, and N 2 sorption. It possesses various multifunctionally structural characteristics such as hollow cavity which can improve mass transfer, the adjacent of the inner HKUST-1 shell to the void which enables the matrix of the shell to host and well disperse MNPs, and an outer ZIF-8 shell which acts as protective layer against the leaching of MNPs and a sieve to guarantee molecular-size selectivity. This makes the material eligible candidates for the heterogeneous catalyst. As a proof of concept, the liquid-phase hydrogenation of olefins with different molecular sizes as a model reaction is employed. It demonstrates the efficient catalytic activity and size-selectivity of Void@HKUST-1/Pd@ZIF-8. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shell feature: a new radiomics descriptor for predicting distant failure after radiotherapy in non-small cell lung cancer and cervix cancer

Science.gov (United States)

Hao, Hongxia; Zhou, Zhiguo; Li, Shulong; Maquilan, Genevieve; Folkert, Michael R.; Iyengar, Puneeth; Westover, Kenneth D.; Albuquerque, Kevin; Liu, Fang; Choy, Hak; Timmerman, Robert; Yang, Lin; Wang, Jing

2018-05-01

Distant failure is the main cause of human cancer-related mortalities. To develop a model for predicting distant failure in non-small cell lung cancer (NSCLC) and cervix cancer (CC) patients, a shell feature, consisting of outer voxels around the tumor boundary, was constructed using pre-treatment positron emission tomography (PET) images from 48 NSCLC patients received stereotactic body radiation therapy and 52 CC patients underwent external beam radiation therapy and concurrent chemotherapy followed with high-dose-rate intracavitary brachytherapy. The hypothesis behind this feature is that non-invasive and invasive tumors may have different morphologic patterns in the tumor periphery, in turn reflecting the differences in radiological presentations in the PET images. The utility of the shell was evaluated by the support vector machine classifier in comparison with intensity, geometry, gray level co-occurrence matrix-based texture, neighborhood gray tone difference matrix-based texture, and a combination of these four features. The results were assessed in terms of accuracy, sensitivity, specificity, and AUC. Collectively, the shell feature showed better predictive performance than all the other features for distant failure prediction in both NSCLC and CC cohorts.

Design and characterization of core-shell mPEG-PLGA composite microparticles for development of cell-scaffold constructs

DEFF Research Database (Denmark)

Wen, Yanhong; Gallego, Monica Ramos; Nielsen, Lene Feldskov

2013-01-01

/DS or Alg/CS/DS particles in the mPEG-PLGA microparticles were significantly dependent on the operating conditions, including the flow rate ratio (Qout/Qin) and the viscosity of the polymer solutions (Vout, Vin) between the outer and the inner feeding channels. The core-shell composite microparticles.......e. more sustainable cell growth was induced by the DS released from the core-shell composite microparticles comprising Alg/CS/DS particles. After seeding fibroblasts onto the composite microparticles, excellent cell adhesion was observed, and a successful assembly of the cell-scaffold constructs...... was induced within 7 days. Therefore, the present study demonstrates a novel strategy for fabrication of core-shell composite microparticles comprising additional particulate drug carriers in the core, which provides controlled delivery of DS and favorable cell biocompatibility; an approach to potentially...

Numerical simulations of thermal convection in a rotating spherical fluid shell at high Taylor and Rayleigh numbers

International Nuclear Information System (INIS)

Sun, Z.; Schubert, G.

1995-01-01

In this study, we carry out numerical simulations of thermal convection in a rapidly rotating spherical fluid shell at high Taylor number Ta and Rayleigh number R with a nonlinear, three-dimensional, time-dependent, spectral-transform code. The parameters used in the simulations are chosen to be in a range which allows us to study two different types of convection, i.e., single column and multi-layered types, and the transition between them. Numerical solutions feature highly time-dependent north--south open columnar convective cells. The cells occur irregularly in longitude, are quasi-layered in cylindrical radius, and maintain alternating bands of mean zonal flow. The complex convective structure and the banded mean zonal flow are results of the high Taylor and Rayleigh numbers. The transition between the two types of convection appears to occur gradually with increasing Rayleigh and Taylor numbers. At a Taylor number of 10 7 the differential rotation pattern consists of an inner cylindrical region of subrotation and an outer cylindrical shell of superrotation manifest at the outer boundary as an equatorial superrotation and a high latitude subrotation. The differential rotation pattern is similar at Ta=10 8 and low Rayleigh number. Cylindrical shells of alternately directed mean zonal flow begin to develop at Ta=10 8 and R=50R c and at Ta=10 9 and R=25R c . This pattern is seen on the outer surface as a latitudinally-banded zonal flow consisting of an equatorial superrotation, a middle and high latitude subrotation, and a polar superrotation. At Ta=10 9 and R=50R c the differential rotation appears at the surface as a broad eastward flow in the equatorial region with alternating bands of westward and eastward flow at high latitudes. copyright 1995 American Institute of Physics

Pd@Au core-shell nanocrystals with concave cubic shapes: kinetically controlled synthesis and electrocatalytic properties.

Science.gov (United States)

Zhang, Ling; Niu, Wenxin; Zhao, Jianming; Zhu, Shuyun; Yuan, Yali; Hua, Lianzhe; Xu, Guobao

2013-01-01

A new type of concave cubic Pd@Au core-shell nanocrystals is synthesized through a kinetically controlled growth process. Pd nanocubes of 56 nm are used as the inner core, and CTAC and Br(-) are used as the capping agent and selective adsorbent, respectively. A suitable ratio of HAuCl4 and cubic Pd seeds and the presence of Br(-) anions are critical to the growth of the concave cubic Pd@Au core-shell nanocrystals. The fast deposition rate on the corners of the cubic Pd seeds promotes the overgrowth of the Au outer shell along the direction, leading to the formation of concave cubic nanostructures. The reduction process is monitored by the surface plasmon resonance spectra of the nanocrystals, and the extinction band became broader and red shifted as the nanocrystals became larger. The electrocatalytic properties of the concave cubic Pd@Au core-shell nanocrystals were investigated with the cathodic electrochemiluminescence reaction of luminol and H2O2. A possible electrocatalytic mechanism was proposed and analyzed.

Improved performance of the LHCb Outer Tracker in LHC Run 2

Science.gov (United States)

d'Argent, P.; Dufour, L.; Grillo, L.; de Vries, J. A.; Ukleja, A.; Aaij, R.; Archilli, F.; Bachmann, S.; Berninghoff, D.; Birnkraut, A.; Blouw, J.; De Cian, M.; Ciezarek, G.; Färber, C.; Demmer, M.; Dettori, F.; Gersabeck, E.; Grabowski, J.; Hulsbergen, W. D.; Khanji, B.; Kolpin, M.; Kucharczyk, M.; Malecki, B. P.; Merk, M.; Mulder, M.; Müller, J.; Mueller, V.; Pellegrino, A.; Pikies, M.; Rachwal, B.; Schmelzer, T.; Spaan, B.; Szczekowski, M.; van Tilburg, J.; Tolk, S.; Tuning, N.; Uwer, U.; Wishahi, J.; Witek, M.

2017-11-01

The LHCb Outer Tracker is a gaseous detector covering an area of 5 × 6 m2 with 12 double layers of straw tubes. The performance of the detector is presented based on data of the LHC Run 2 running period from 2015 and 2016. Occupancies and operational experience for data collected in pp, pPb and PbPb collisions are described. An updated study of the ageing effects is presented showing no signs of gain deterioration or other radiation damage effects. In addition several improvements with respect to LHC Run 1 data taking are introduced. A novel real-time calibration of the time-alignment of the detector and the alignment of the single monolayers composing detector modules are presented, improving the drift-time and position resolution of the detector by 20%. Finally, a potential use of the improved resolution for the timing of charged tracks is described, showing the possibility to identify low-momentum hadrons with their time-of-flight.

Design and analysis of reactor containment of steel-concrete composite laminated shell

International Nuclear Information System (INIS)

Ichikawa, K.

1977-01-01

Reinforced and prestressed concrete containments for reactors have been developed in order to avoid the difficulties of welding of steel containments encountered as their capacities have become large: growing thickness of steel shells gave rise to the requirement of stress relief at the construction sites. However, these concrete vessels also seem to face another difficulty: the lack of shearing resistance capacity. In order to improve the shearing resistance capacity of the containment vessel, while avoiding the difficulty of welding, a new scheme of containment consisting of steel-concrete laminated shell is being developed. In the main part of a cylindrical vessel, the shell consists of two layers of thin steel plates located at the inner and outer surfaces, and a layer of concrete core into which both the steel plates are anchored. In order to validate the feasibility and safety of this new design, the results of analysis on the basis of up-to-date design loads are presented. The results of model tests in 1:30 scale are also reported. (Auth.)

Shell report 2001; Les personnes, la planete, les profits. Shell rapport 2001

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

In 2001, Shell saw mixed results across the social, environmental and economic spectrum. In order to contribute to the sustainable development, the Group is on track towards meeting its target to reduce greenhouse gas emissions to 10 % below 1990 levels by the end of 2002, although there was a significant increase in spill volumes and greenhouse gas emissions rose. Shell has articulated the business case and defined seven principles of sustainable development for use across the Group in business plans and daily operations: generating robust profitability; delivering value to customers; protecting the environment; managing resources; respecting and safeguarding people; benefiting communities; and working with stakeholders. Key points from the Shell Report include: in the framework of Managing, an independent review of the Shell Nigeria Community Development programme and testing of a human rights assessment tool in Shell South Africa and the implementing of a new Diversity and Inclusiveness Standard; in the framework of the economy the cost improvements of 5,1 billion dollars, ahead of target, the second highest earnings ever in difficult market conditions and the election of Shell top brand for fifth year running by motorists; in the framework of the Social, the safety performance, the avoidance of 100 contracts for incompatibility with Shell Business Principles; in the framework of the Environment, the publication of the Fresh water usage report for the first time, the Greenhouse gas emissions, the increase of spills as a result of a small number of incidents including a pipeline rupture in Nigeria and a well blow out in Oman. The economic, environmental and social data of the Shell Report are externally verified. (A.L.B.)

Comparison of core-shell and totally porous ultra high performance liquid chromatographic stationary phases based on their selectivity towards alfuzosin compounds.

Science.gov (United States)

Szulfer, Jarosław; Plenis, Alina; Bączek, Tomasz

2014-06-13

This paper focuses on the application of a column classification system based on the Katholieke Universiteit Leuven for the characterization of physicochemical properties of core-shell and ultra-high performance liquid chromatographic stationary phases, followed by the verification of the reliability of the obtained column classification in pharmaceutical practice. In the study, 7 stationary phases produced in core-shell technology and 18 ultra-high performance liquid chromatographic columns were chromatographically tested, and ranking lists were built on the FKUL-values calculated against two selected reference columns. In the column performance test, an analysis of alfuzosin in the presence of related substances was carried out using the brands of the stationary phases with the highest ranking positions. Next, a system suitability test as described by the European Pharmacopoeia monograph was performed. Moreover, a study was also performed to achieve a purposeful shortening of the analysis time of the compounds of interest using the selected stationary phases. Finally, it was checked whether methods using core-shell and ultra-high performance liquid chromatographic columns can be an interesting alternative to the high-performance liquid chromatographic method for the analysis of alfuzosin in pharmaceutical practice. Copyright © 2014 Elsevier B.V. All rights reserved.

Nanostructured core-shell electrode materials for electrochemical capacitors

Science.gov (United States)

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

2016-11-01

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

From core/shell to hollow Fe/γ-Fe_2O_3 nanoparticles: evolution of the magnetic behavior

International Nuclear Information System (INIS)

Nemati, Z; Khurshid, H; Alonso, J; Phan, M H; Mukherjee, P; Srikanth, H

2015-01-01

High quality Fe/γ-Fe_2O_3 core/shell, core/void/shell, and hollow nanoparticles with two different sizes of 8 and 12 nm were synthesized, and the effect of morphology, surface and finite-size effects on their magnetic properties including the exchange bias (EB) effect were systematically investigated. We find a general trend for both systems that as the morphology changes from core/shell to core/void/shell, the magnetization of the system decays and inter-particle interactions become weaker, while the effective anisotropy and the EB effect increase. The changes are more drastic when the nanoparticles become completely hollow. Noticeably, the morphological change from core/shell to hollow increases the mean blocking temperature for the 12 nm particles but decreases for the 8 nm particles. The low-temperature magnetic behavior of the 12 nm particles changes from a collective super-spin-glass system mediated by dipolar interactions for the core/shell nanoparticles to a frustrated cluster glass-like state for the shell nanograins in the hollow morphology. On the other hand for the 8 nm nanoparticles core/shell and hollow particles the magnetic behavior is more similar, and a conventional spin glass-like transition is obtained at low temperatures. In the case of the hollow nanoparticles, the coupling between the inner and outer spin layers in the shell gives rise to an enhanced EB effect, which increases with increasing shell thickness. This indicates that the morphology of the shell plays a crucial role in this kind of exchange-biased systems. (paper)

Enhanced thermoelectric transport in modulation-doped GaN/AlGaN core/shell nanowires.

Science.gov (United States)

Song, Erdong; Li, Qiming; Swartzentruber, Brian; Pan, Wei; Wang, George T; Martinez, Julio A

2016-01-08

The thermoelectric properties of unintentionally n-doped core GaN/AlGaN core/shell N-face nanowires are reported. We found that the temperature dependence of the electrical conductivity is consistent with thermally activated carriers with two distinctive donor energies. The Seebeck coefficient of GaN/AlGaN nanowires is more than twice as large as that for the GaN nanowires alone. However, an outer layer of GaN deposited onto the GaN/AlGaN core/shell nanowires decreases the Seebeck coefficient at room temperature, while the temperature dependence of the electrical conductivity remains the same. We attribute these observations to the formation of an electron gas channel within the heavily-doped GaN core of the GaN/AlGaN nanowires. The room-temperature thermoelectric power factor for the GaN/AlGaN nanowires can be four times higher than the GaN nanowires. Selective doping in bandgap engineered core/shell nanowires is proposed for enhancing the thermoelectric power.

77 FR 3771 - Notice of Issuance of Final Outer Continental Shelf Air Permit for Shell Offshore, Inc.

Science.gov (United States)

2012-01-25

... locations within Shell's DeSoto Canyon and Lloyd Ridge lease locations on the OCS in the Gulf of Mexico... INFORMATION CONTACT: Lori Shepherd, Air Permits Section, Air Planning Branch, Air, Pesticides and Toxics... effective on December 30, 2011. Dated: January 12, 2012. Beverly H. Banister, Director, Air, Pesticides and...

Acute Zonal Cone Photoreceptor Outer Segment Loss.

Science.gov (United States)

Aleman, Tomas S; Sandhu, Harpal S; Serrano, Leona W; Traband, Anastasia; Lau, Marisa K; Adamus, Grazyna; Avery, Robert A

2017-05-01

The diagnostic path presented narrows down the cause of acute vision loss to the cone photoreceptor outer segment and will refocus the search for the cause of similar currently idiopathic conditions. To describe the structural and functional associations found in a patient with acute zonal occult photoreceptor loss. A case report of an adolescent boy with acute visual field loss despite a normal fundus examination performed at a university teaching hospital. Results of a complete ophthalmic examination, full-field flash electroretinography (ERG) and multifocal ERG, light-adapted achromatic and 2-color dark-adapted perimetry, and microperimetry. Imaging was performed with spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) and short-wavelength (SW) fundus autofluorescence (FAF), and NIR reflectance (REF). The patient was evaluated within a week of the onset of a scotoma in the nasal field of his left eye. Visual acuity was 20/20 OU, and color vision was normal in both eyes. Results of the fundus examination and of SW-FAF and NIR-FAF imaging were normal in both eyes, whereas NIR-REF imaging showed a region of hyporeflectance temporal to the fovea that corresponded with a dense relative scotoma noted on light-adapted static perimetry in the left eye. Loss in the photoreceptor outer segment detected by SD-OCT co-localized with an area of dense cone dysfunction detected on light-adapted perimetry and multifocal ERG but with near-normal rod-mediated vision according to results of 2-color dark-adapted perimetry. Full-field flash ERG findings were normal in both eyes. The outer nuclear layer and inner retinal thicknesses were normal. Localized, isolated cone dysfunction may represent the earliest photoreceptor abnormality or a distinct entity within the acute zonal occult outer retinopathy complex. Acute zonal occult outer retinopathy should be considered in patients with acute vision loss and abnormalities on NIR-REF imaging, especially if

One-by-one imprinting in two eccentric layers of hollow core-shells: Sequential electroanalysis of anti-HIV drugs.

Science.gov (United States)

Singh, Kislay; Jaiswal, Swadha; Singh, Richa; Fatma, Sana; Prasad, Bhim Bali

2018-07-15

Double layered one-by-one imprinted hollow core-shells@ pencil graphite electrode was fabricated for sequential sensing of anti-HIV drugs. For this, two eccentric layers were developed on the surface of vinylated silica nanospheres to obtain double layered one-by-one imprinted solid core-shells. This yielded hollow core-shells on treatment with hydrofluoric acid. The modified hollow core-shells (single layered dual imprinted) evolved competitive diffusion of probe/analyte molecules. However, the corresponding double layered one-by-one imprinted hollow core-shells (outer layer imprinted with Zidovudine, and inner layer with Lamivudine) were found relatively better owing to their bilateral diffusions into molecular cavities, without any competition. The entire work is based on differential pulse anodic stripping voltammetry at double layered one-by-one imprinted hollow core-shells. This resulted in indirect detection of electro inactive targets with limits of detection as low as 0.91 and 0.12 (aqueous sample), 0.94 and 0.13 (blood serum), and 0.99 and 0.20 ng mL -1 (pharmaceutics) for lamivudine and zidovudine, respectively in anti-HIV drug combination. Copyright © 2018 Elsevier B.V. All rights reserved.

ESTIMATING HIGH LEVEL WASTE MIXING PERFORMANCE IN HANFORD DOUBLE SHELL TANKS

International Nuclear Information System (INIS)

Thien, M.G.; Greer, D.A.; Townson, P.

2011-01-01

The ability to effectively mix, sample, certify, and deliver consistent batches of high level waste (HLW) feed from the Hanford double shell tanks (DSTs) to the Waste Treatment and Immobilization Plant (WTP) presents a significant mission risk with potential to impact mission length and the quantity of HLW glass produced. The Department of Energy's (DOE's) Tank Operations Contractor (TOC), Washington River Protection Solutions (WRPS) is currently demonstrating mixing, sampling, and batch transfer performance in two different sizes of small-scale DSTs. The results of these demonstrations will be used to estimate full-scale DST mixing performance and provide the key input to a programmatic decision on the need to build a dedicated feed certification facility. This paper discusses the results from initial mixing demonstration activities and presents data evaluation techniques that allow insight into the performance relationships of the two small tanks. The next steps, sampling and batch transfers, of the small scale demonstration activities are introduced. A discussion of the integration of results from the mixing, sampling, and batch transfer tests to allow estimating full-scale DST performance is presented.

Simultaneous saccharification and fermentation (SSF) of Jatropha curcas shells: utilization of co-products from the biodiesel production process.

Science.gov (United States)

Visser, Evan Michael; Oliveira Filho, Delly; Tótola, Marcos Rogério; Martins, Marcio Arêdes; Guimarães, Valéria Monteze

2012-06-01

Jatropha curcas has great potential as an oil crop for use in biodiesel applications, and the outer shell is rich in lignocellulose that may be converted to ethanol, giving rise to the concept of a biorefinery. In this study, two dilute pretreatments of 0.5% H(2)SO(4) and 1.0% NaOH were performed on Jatropha shells with subsequent simultaneous saccharification and fermentation (SSF) of the pretreated water-insoluble solids (WIS) to evaluate the effect of inhibitors in the pretreatment slurry. A cellulase loading of 15 FPU/g WIS, complimented with an excess of cellobiase (19.25 U/g), was used for SSF of either the washed WIS or the original slurry to determine the effect of inhibitors. Ethanol and glucose were monitored during SSF of 20 g of pretreated biomass. The unwashed slurry showed to have a positive effect on SSF efficiency for the NaOH-pretreated biomass. Maximum efficiencies of glucan conversion to ethanol in the WIS were 40.43% and 41.03% for the H(2)SO(4)- and NaOH-pretreated biomasses, respectively.

Facile synthesis of core–shell structured PANI-Co_3O_4 nanocomposites with superior electrochemical performance in supercapacitors

International Nuclear Information System (INIS)

Hai, Zhenyin; Gao, Libo; Zhang, Qiang; Xu, Hongyan; Cui, Danfeng; Zhang, Zengxing; Tsoukalas, Dimitris; Tang, Jun; Yan, Shubin; Xue, Chenyang

2016-01-01

Graphical abstract: - Highlights: • PANI-Co_3O_4 is synthesized by carbon-assisted and in situ polymerization methods. • PANI coating improves the properties of Co_3O_4 affecting electrochemical performance. • The nanocomposites exhibit a high specific capacitance of 1184 F g"−"1 at 1.25 A g"−"1. - Abstract: Core–shell structured PANI-Co_3O_4 nanocomposites for supercapacitor applications were synthesized by combination of carbon-assisted method and in situ polymerization method. The crystalline structure, optical band gap, morphology, and hydrophilic property, as the major factors affecting the performances of supercapacitors, were investigated by X-ray diffraction (XRD), UV–vis spectrophotometry (UV–vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and water contact angle (WCA). The core–shell structured PANI-Co_3O_4 nanocomposites are characterized by amorphous PANI, small bandgaps, large surface area and favorable hydrophilicity, which indicates the superior electrochemical performances of the nanocomposites as electrode material for supercapacitors. Cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurements were conducted in 6 M KOH aqueous solution to evaluate the electrochemical performances. The results shows that core–shell structured PANI-Co_3O_4 nanocomposites exhibit a high specific capacitance of 1184 F g"−"1 at 1.25 A g"−"1, excellent cycling stability of a capacitance retention of 84.9% after 1000 galvanostatic charge/discharge cycles, good electrical conductivity and ion diffusion behavior.

Analyses of a steel containment vessel with an outer contact structure under severe internal overpressurization conditions

International Nuclear Information System (INIS)

Porter, V.L.

1994-01-01

Many Mark-I and Mark-II BWR plants are designed with a steel vessel as the primary containment. Typically, the steel containment vessel (SCV) is enclosed within a reinforced concrete shield building with only a small gap (74-90 mm) separating the two structures. This paper describes finite element analyses performed to evaluate the effects of contact and friction between a steel containment vessel and an outer contact structure when the containment vessel is subjected to large internal pressures. These computations were motivated by a joint program on containment integrity involving the Nuclear Power Engineering Corporation (NUPEC) of Japan, the US Nuclear Regulatory Commission (NRC), and Sandia National Laboratories for testing model containments. Under severe accident loading conditions, the steel containment vessel in a typical Mark-I or Mark-II plant may deform under internal pressurization such that it contacts the inner surface of a shield building wall. (Thermal expansion from increasing accident temperatures would also close the gap between the SCV and the shield building, but temperature effects are not considered in these analyses.) The amount and location of contact and the pressure at which it occurs all affect how the combined structure behaves. A preliminary finite element model has been developed to analyze a model of a typical steel containment vessel con-ling into contact with an outer structure. Both the steel containment vessel and the outer contact structure were modelled with axisymmetric shell finite elements. Of particular interest are the influence that the contact structure has on deformation and potential failure modes of the containment vessel. Furthermore, the coefficient of friction between the two structures was varied to study its effects on the behavior of the containment vessel and on the uplift loads transmitted to the contact structure. These analyses show that the material properties of an outer contact structure and the amount

Mesoporous coaxial titanium nitride-vanadium nitride fibers of core-shell structures for high-performance supercapacitors.

Science.gov (United States)

Zhou, Xinhong; Shang, Chaoqun; Gu, Lin; Dong, Shanmu; Chen, Xiao; Han, Pengxian; Li, Lanfeng; Yao, Jianhua; Liu, Zhihong; Xu, Hongxia; Zhu, Yuwei; Cui, Guanglei

2011-08-01

In this study, titanium nitride-vanadium nitride fibers of core-shell structures were prepared by the coaxial electrospinning, and subsequently annealed in the ammonia for supercapacitor applications. These core-shell (TiN-VN) fibers incorporated mesoporous structure into high electronic conducting transition nitride hybrids, which combined higher specific capacitance of VN and better rate capability of TiN. These hybrids exhibited higher specific capacitance (2 mV s(-1), 247.5 F g(-1)) and better rate capability (50 mV s(-1), 160.8 F g(-1)), which promise a good candidate for high-performance supercapacitors. It was also revealed by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) characterization that the minor capacitance fade originated from the surface oxidation of VN and TiN.

Tube-in-shell heat exchangers

International Nuclear Information System (INIS)

Richardson, J.

1976-01-01

Tube-in-shell heat exchangers normally comprise a bundle of parallel tubes within a shell container, with a fluid arranged to flow through the tubes in heat exchange with a second fluid flowing through the shell. The tubes are usually end supported by the tube plates that separate the two fluids, and in use the tube attachments to the tube plates and the tube plates can be subject to severe stress by thermal shock and frequent inspection and servicing are required. Where the heat exchangers are immersed in a coolant such as liquid Na such inspection is difficult. In the arrangement described a longitudinally extending central tube is provided incorporating axially spaced cylindrical tube plates to which the opposite ends of the tubes are attached. Within this tube there is a tubular baffle that slidably seals against the wall of the tube between the cylindrical tube plates to define two co-axial flow ducts. These ducts are interconnected at the closed end of the tube by the heat exchange tubes and the baffle comprises inner and outer spaced walls with the interspace containing Ar. The baffle is easily removable and can be withdrawn to enable insertion of equipment for inspecting the wall of the tube and tube attachments and to facilitate plugging of defective tubes. Cylindrical tube plates are believed to be superior for carrying pressure loads and resisting the effects of thermal shock. Some protection against thermal shock can be effected by arranging that the secondary heat exchange fluid is on the tube side, and by providing a thermal baffle to prevent direct impingement of hot primary fluid on to the cylindrical tube plates. The inner wall of the tubular baffle may have flexible expansible region. Some nuclear reactor constructions incorporating such an arrangement are described, including liquid metal reactors. (U.K.)

Development of Mortar Simulator with Shell-In-Shell System – Problem of External Ballistics

Directory of Open Access Journals (Sweden)

A. Fedaravicius

2007-01-01

Full Text Available The shell-in-shell system used in the mortar simulator raises a number of non-standard technical and computational problems starting from the requirement to distribute the propelling blast energy between the warhead and the ballistic barrel, finishing with the requirement that the length of warhead's flight path must be scaled to combat shell firing tables. The design problem of the simulator is split into two parts – the problem of external ballistics where the initial velocities of the warhead must be determined, and the problem of internal ballistics – where the design of the cartridge and the ballistic barrel must be performed.

MIL-125-NH2@TiO2 Core-Shell Particles Produced by a Post-Solvothermal Route for High-Performance Photocatalytic H2 Production.

Science.gov (United States)

Zhang, Bingxing; Zhang, Jianling; Tan, Xiuniang; Shao, Dan; Shi, Jinbiao; Zheng, Lirong; Zhang, Jing; Yang, Guanying; Han, Buxing

2018-05-02

Metal-organic frameworks (MOFs) have proven to be an interesting class of sacrificial precursors of functional inorganic materials for catalysis, energy storage, and conversion applications. However, the controlled synthesis of MOF-derived materials with desirable compositions, structures, and properties still remains a big challenge. Herein, we propose a post-solvothermal route for the outer-to-inner loss of organic linkers from MOF, which is simple, rapid, and controllable and can be operated at temperature much lower than that of the commonly adopted pyrolysis method. By such a strategy, the MIL-125-NH 2 particles coated by TiO 2 nanosheets were produced, and the thickness of TiO 2 shell can be easily tuned. The MIL-125-NH 2 @TiO 2 core-shell particles combine the advantages of highly active TiO 2 nanosheets, MIL-125-NH 2 photosensitizer, plenty of linker defects and oxygen vacancies, and mesoporous structure, which allows them to be utilized as photocatalysts for the visible-light-driven hydrogen production reaction. It is remarkable that the hydrogen evolution rate by MIL-125-NH 2 @TiO 2 can be enhanced 70 times compared with the pristine MIL-125-NH 2 . Such a route can be easily applied to the synthesis of different kinds of MOF-derived functional materials.

First-Ply-Failure Performance of Composite Clamped Spherical Shells

Science.gov (United States)

Ghosh, A.; Chakravorty, D.

2018-05-01

The failure aspects of composites are available for plates, but studies of the literature on shells unveils that similar reports on them are very limited in number. The aim of this work was to investigate the first-ply-failure of industrially and aesthetically important spherical shells under uniform loadings. Apart from solving benchmark problems, numerical experiments were carried out with different variations of their parameters to obtain the first-ply-failure stresses by using the finite-element method. The load was increased in steps, and the lamina strains and stresses were put into well-established failure criteria to evaluate their first-ply-failure stress, the failed ply, the point of initiation of failure, and failure modes and tendencies. The results obtained are analyzed to extract the points of engineering significance.

Exergetic optimization of shell and tube heat exchangers using a genetic based algorithm

Energy Technology Data Exchange (ETDEWEB)

Oezcelik, Yavuz [Ege University, Bornova, Izmir (Turkey). Engineering Faculty, Chemical Engineering Department

2007-08-15

In the computer-based optimization, many thousands of alternative shell and tube heat exchangers may be examined by varying the high number of exchanger parameters such as tube length, tube outer diameter, pitch size, layout angle, baffle space ratio, number of tube side passes. In the present study, a genetic based algorithm was developed, programmed, and applied to estimate the optimum values of discrete and continuous variables of the MINLP (mixed integer nonlinear programming) test problems. The results of the test problems show that the genetic based algorithm programmed can estimate the acceptable values of continuous variables and optimum values of integer variables. Finally the genetic based algorithm was extended to make parametric studies and to find optimum configuration of heat exchangers by minimizing the sum of the annual capital cost and exergetic cost of the shell and tube heat exchangers. The results of the example problems show that the proposed algorithm is applicable to find optimum and near optimum alternatives of the shell and tube heat exchanger configurations. (author)

HPLC-CUPRAC post-column derivatization method for the determination of antioxidants: a performance comparison between porous silica and core-shell column packing.

Science.gov (United States)

Haque, Syed A; Cañete, Socrates Jose P

2018-01-01

An HPLC method employing a post-column derivatization strategy using the cupric reducing antioxidant capacity reagent (CUPRAC reagent) for the determining antioxidants in plant-based materials leverages the separation capability of regular HPLC approaches while allowing for detection specificity for antioxidants. Three different column types, namely core-shell and porous silica including two chemically different core-shell materials (namely phenyl-hexyl and C18), were evaluated to assess potential improvements that could be attained by changing from a porous silica matrix to a core-shell matrix. Tea extracts were used as sample matrices for the evaluation specifically looking at catechin and epigallocatechin gallate (EGCG). Both the C18 and phenyl-hexyl core-shell columns showed better performance compared to the C18 porous silica one in terms of separation, peak shape, and retention time. Among the two core-shell materials, the phenyl-hexyl column showed better resolving power compared to the C18 column. The CUPRAC post-column derivatization method can be improved using core-shell columns and suitable for quantifying antioxidants, exemplified by catechin and EGCG, in tea samples.

Study of characterization of trace elements in marine shells of Sambaqui: correlation between recent and old shells

International Nuclear Information System (INIS)

Gomez, Mauro Roger Batista Pousada; Rocha, Flavio Roberto; Silva, Paulo Sergio Cardoso da

2013-01-01

Calcium carbonate of recent and ancient C. rhizophorae oyster shells was analyzed for the determination of trace elements by instrumental neutron activation analysis. The ancient shells belong to a Sambaqui located in Cananeia region, South of Sao Paulo state and the recent ones are from an oyster production farm in the same region Studies related to the element concentrations in molluscs shell has been done as a tentative of establishing the element concentrations with palio-environmental factor. In this study it was aimed to verify differences in the elemental constitution of recent and ancient oyster shells that present potential for being used as indicator of marine changes. Results indicated that the elements Br, Ce, La, Na, Sm and An are higher in recent shells and the elements Cr, Fe Sc and Th are higher in ancient shells. Statistical analyses performed indicated that the enrichment of the light rare earth elements related to Ca are possibly good candidates for these palio-environmental studies. (author)

Shell Venster

International Nuclear Information System (INIS)

De Wit, P.; Looijesteijn, B.; Regeer, B.; Stip, B.

1995-03-01

In the bi-monthly issues of 'Shell Venster' (window on Shell) attention is paid to the activities of the multinational petroleum company Shell Nederland and the Koninklijke/Shell Groep by means of non-specialist articles

On the uncertainties in the shell correction by Strutinsky smearing procedure for certain shapes relevant in fission

International Nuclear Information System (INIS)

Ramamurthy, V.S.; Prakash, M.; Kapoor, S.

1976-01-01

It is found that for level schemes obtained from a folded Yukawa potential, the Strutinsky smearing procedure for the evaluation of the shell correction to the total potential energy of nuclei does not lead to a unique value for nuclear shapes near and beyond the outer fission barrier deformations and consequently introduces uncertainties in the relative fission barrier heights. (author)

Management of outer space

Science.gov (United States)

Perek, Lubos

1993-10-01

Various aspects of space-environment management are discussed. Attention is called to the fact that, while space radio communications are already under an adequate management by the International Communications Union, the use of nuclear power sources is regulated by the recently adopted set of principles, and space debris will be discussed in the near future at the UN COPUOS, other aspects of management of outer space received little or no attention of the international community. These include the competency of crews and technical equipment of spacecraft launched by newcomers to space exploration; monitoring of locations and motions of space objects (now in national hands), with relevant data made accessible through a computer network; and the requirement to use space only for beneficial purposes and not for promoting narrow and debatable interests damaging the outer space environment and impeding on astronomical observations. It is suggested that some of these tasks would be best performed by an international space agency within the UN system of organizations.

Ionization effects in electronic inner-shells of ionized atoms

International Nuclear Information System (INIS)

Shchornak, G.

1983-01-01

A review of the atomic physics of ionization atoms has been presented. Interaction and structure effects in atomic shells, correlated to the occurrence of vacancies in several subshells of the atom have been considered. The methods of calculations of atomic states and wave functions have been reviewed. The energy shift of characteristic X-rays is discussed as a function of the ionization stage of the atom. The influence of inner and outer-shell vacancies on the energy of the X-rays is shown in detail. The influence of chemical effects on the parameters of X-rays is also taken into account. Further on, the change of transition probabilities in radiative and non-radiative transitions by changing stage of ionization is discussed; and among them the leading part of Auger and Coster-Kronig transitions by the arearrangement of the atomic states is shown. The influence of non-radiative electronic transitions on ionization cross-sections for multiple ionization is discussed. Using these results, ionization cross-sections for direct and indirect processes for several ionization stages are given

Control of Compact-Toroid Characteristics by External Copper Shell

Science.gov (United States)

Matsumoto, T.; Sekiguchi, J.; Asai, T.; Gota, H.; Roche, T.; Allfrey, I.; Cordero, M.; Garate, E.; Kinley, J.; Valentine, T.; Waggoner, W.; the TAE Team

2015-11-01

A collaborative research project by Tri Alpha Energy and Nihon University has been conducted for several years, which led to the development of a new compact toroid (CT) injector for efficient FRC particle refueling in the C-2U experiment. The CT is formed by a magnetized coaxial plasma gun (MCPG), consisting of coaxial cylindrical electrodes. In CT formation via MCPG, the magnetic helicity content of the generated CT is one of the critical parameters. A bias coil is inserted into the inner electrode to generate a poloidal flux. The resultant bias magnetic field is spread out of MCPG with time due to its low-frequency bias current. To obtain a more effectively distributed bias magnetic field as well as to improve the voltage breakdown between electrodes, the MCPG incorporates a novel ~ 1 mm thick copper shell mounted outside of the outer electrode. This allows for reliable and controlled operation and more robust CT generation. A detailed discussion of the copper shell and experimental test results will be presented.

Effect of Hybrid Talc-Basalt Fillers in the Shell Layer on Thermal and Mechanical Performance of Co-Extruded Wood Plastic Composites.

Science.gov (United States)

Huang, Runzhou; Mei, Changtong; Xu, Xinwu; Kärki, Timo; Lee, Sunyoung; Wu, Qinglin

2015-12-08

Hybrid basalt fiber (BF) and Talc filled high density polyethylene (HDPE) and co-extruded wood-plastic composites (WPCs) with different BF/Talc/HDPE composition levels in the shell were prepared and their mechanical, morphological and thermal properties were characterized. Incorporating BFs into the HDPE-Talc composite substantially enhanced the thermal expansion property, flexural, tensile and dynamic modulus without causing a significant decrease in the tensile and impact strength of the composites. Strain energy estimation suggested positive and better interfacial interactions of HDPE with BFs than that with talc. The co-extruded structure design improved the mechanical properties of WPC due to the protective shell layer. The composite flexural and impact strength properties increased, and the thermal expansion decreased as BF content increased in the hybrid BF/Talc filled shells. The cone calorimetry data demonstrated that flame resistance of co-extruded WPCs was improved with the use of combined fillers in the shell layer, especially with increased loading of BFs. The combined shell filler system with BFs and Talc could offer a balance between cost and performance for co-extruded WPCs.

Valence shell photoionization energies and cross-sections of NF sub 3 and PF sub 3

CERN Document Server

Jürgensen, A

2003-01-01

Relative outer valence shell ionization potentials and cross-sections were determined for the isostructural, Group 15, trifluorides NF sub 3 and PF sub 3 in the gas phase using synchrotron radiation. Excitation photon energies ranged from 70 to 160 eV. The experimental spectra were assigned and cross-sections analyzed with the aid of both MS-X alpha and ab initio calculations. Spectral differences in peak energies and relative intensities are related to structural and electronic differences between these two fluoride molecules. Valence shell ionization potentials were compared to calculated values obtained by several different methods. The partial photoionization cross-sections for each orbital were obtained as a function of excitation energy and compared to theoretical results obtained with the X alpha method.

Seaurchin-like hierarchical NiCo2O4@NiMoO4 core-shell nanomaterials for high performance supercapacitors.

Science.gov (United States)

Zhang, Qiang; Deng, Yanghua; Hu, Zhonghua; Liu, Yafei; Yao, Mingming; Liu, Peipei

2014-11-14

A novel electrode material of the three-dimensional (3D) multicomponent oxide NiCo2O4@NiMoO4 core-shell was synthesized via a facile two-step hydrothermal method using a post-annealing procedure. The uniform NiMoO4 nanosheets were grown on the seaurchin-like NiCo2O4 backbone to form a NiCo2O4@NiMoO4 core-shell material constructed by interconnected ultrathin nanosheets, so as to produce hierarchical mesopores with a large specific surface area of 100.3 m(2) g(-1). The porous feature and core-shell structure can facilitate the penetration of electrolytic ions and increases the number of electroactive sites. Hence, the NiCo2O4@NiMoO4 material exhibited a high specific capacitance of 2474 F g(-1) and 2080 F g(-1) at current densities of 1 A g(-1) and 20 A g(-1) respectively, suggesting that it has not only a very large specific capacitance, but also a good rate performance. In addition, the capacitance loss was only 5.0% after 1000 cycles of charge and discharge tests at the current density of 10 A g(-1), indicating high stability. The excellent electrochemical performance is mainly attributed to its 3D core-shell and hierarchical mesoporous structures which can provide unobstructed pathways for the fast diffusion and transportation of ions and electrons, a large number of active sites and good strain accommodation.

Outer magnetosphere

International Nuclear Information System (INIS)

Schardt, A.W.; Behannon, K.W.; Lepping, R.P.; Carbary, J.F.; Eviatar, A.; Siscoe, G.L.

1984-01-01

Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc

Importance-truncated shell model for multi-shell valence spaces

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Christina; Vobig, Klaus; Roth, Robert [Institut fuer Kernphysik, TU Darmstadt (Germany)

2016-07-01

The valence-space shell model is one of the work horses in nuclear structure theory. In traditional applications, shell-model calculations are carried out using effective interactions constructed in a phenomenological framework for rather small valence spaces, typically spanned by one major shell. We improve on this traditional approach addressing two main aspects. First, we use new effective interactions derived in an ab initio approach and, thus, establish a connection to the underlying nuclear interaction providing access to single- and multi-shell valence spaces. Second, we extend the shell model to larger valence spaces by applying an importance-truncation scheme based on a perturbative importance measure. In this way, we reduce the model space to the relevant basis states for the description of a few target eigenstates and solve the eigenvalue problem in this physics-driven truncated model space. In particular multi-shell valence spaces are not tractable otherwise. We combine the importance-truncated shell model with refined extrapolation schemes to approximately recover the exact result. We present first results obtained in the importance-truncated shell model with the newly derived ab initio effective interactions for multi-shell valence spaces, e.g., the sdpf shell.

Recent evolution of theoretical models in inner shell photoionization

International Nuclear Information System (INIS)

Combet Farnoux, F.

1978-01-01

This paper is a brief review of various atomic theoretical models recently developed to calculate photoionization cross sections in the low energy range (from the far ultraviolet to the soft X ray region). For both inner and outer shells concerned, we emphasize the necessity to go beyond the independent particle models by means of the introduction of correlation effects in both initial and final states. The basic physical ideas of as elaborated models as Random Phase Approximation with exchange, Many Body Perturbation Theory and R matrix Theory are outlined and summarized. As examples, the results of some calculations are shown and compared with experiment

Double-shelled silicon anode nanocomposite materials: A facile approach for stabilizing electrochemical performance via interface construction

Science.gov (United States)

Du, Lulu; Wen, Zhongsheng; Wang, Guanqin; Yang, Yan-E.

2018-04-01

The rapid capacity fading induced by volumetric changes is the main issue that hinders the widespread application of silicon anode materials. Thus, double-shelled silicon composite materials where lithium silicate was located between an Nb2O5 coating layer and a silicon active core were configured to overcome the chemical compatibility issues related to silicon and oxides. The proposed composites were prepared via a facile co-precipitation method combined with calcination. Transmission electron microscopy and X-ray photoelectron spectroscopy analysis demonstrated that a transition layer of lithium silicate was constructed successfully, which effectively hindered the thermal inter-diffusion between the silicon and oxide coating layers during heat treatment. The electrochemical performance of the double-shelled silicon composites was enhanced dramatically with a retained specific capacity of 1030 mAh g-1 after 200 cycles at a current density of 200 mA g-1 compared with 598 mAh g-1 for a core-shell Si@Nb2O5 composite that lacked the interface. The lithium silicate transition layer was shown to play an important role in maintaining the high electrochemical stability.

Rapid synthesis and characterization of hybrid ZnO@Au core–shell nanorods for high performance, low temperature NO{sub 2} gas sensor applications

Energy Technology Data Exchange (ETDEWEB)

Ponnuvelu, Dinesh Veeran [Nanosensor Laboratory, PSG Institute of Advanced Studies, Coimbatore 641 004 (India); Pullithadathil, Biji, E-mail: bijuja123@yahoo.co.in [Nanosensor Laboratory, PSG Institute of Advanced Studies, Coimbatore 641 004 (India); Prasad, Arun K.; Dhara, Sandip [Surface and Nanoscience Division, Indira Gandhi Center for Atomic Research, Kalpakkam (India); Ashok, Anuradha [Nanosensor Laboratory, PSG Institute of Advanced Studies, Coimbatore 641 004 (India); Mohamed, Kamruddin; Tyagi, Ashok Kumar [Surface and Nanoscience Division, Indira Gandhi Center for Atomic Research, Kalpakkam (India); Raj, Baldev [Nanosensor Laboratory, PSG Institute of Advanced Studies, Coimbatore 641 004 (India)

2015-11-15

Graphical abstract: - Highlights: • Hybrid ZnO@Au core–shell nanorods were developed using rapid chemical method that can be used as a high performance, low temperature NO{sub 2} gas sensor. • Surface defect analysis (PL and XPS) clearly illustrates the presence of surface oxygen species and Zn interstitials involved in charge transport properties in-turn affecting gas sensing properties. • Hybrid ZnO@Au core–shell nanorods establish enhanced gas sensing performance at 150 °C compared to ZnO (300 °C) with a lower detection limit of 500 ppb using conventional electrodes. • The enhanced performance of ZnO@Au core–shell nanorods based sensor was owing to the presence of Au nanoclusters on the surface of ZnO nanorods which is attributed to the formation of Schottky contacts at the interfaces leading to sensitization effects. • The hybrid material found to be selective toward NO{sub 2} gas and highly stable in nature. - Abstract: A rapid synthesis route for hybrid ZnO@Au core–shell nanorods has been realized for ultrasensitive, trace-level NO{sub 2} gas sensor applications. ZnO nanorods and hybrid ZnO@Au core–shell nanorods are structurally analyzed using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Optical characterization using UV–visible (UV–vis), photoluminescence (PL) and Raman spectroscopies elucidate alteration in the percentage of defect and charge transport properties of ZnO@Au core–shell nanorods. The study reveals the accumulation of electrons at metal–semiconductor junctions leading to upward band bending for ZnO and thus favors direct electron transfer from ZnO to Au nanoclusters, which mitigates charge carrier recombination process. The operating temperature of ZnO@Au core–shell nanorods based sensor significantly decreased to 150 °C compared to alternate NO{sub 2} sensors (300 °C). Moreover, a linear sensor response in the range of 0.5–5

Review of supercontainer copper shell-bentonite interactions and possible effects on buffer performance for the KBS-3H design

International Nuclear Information System (INIS)

King, F.; Wersin, P.

2014-03-01

A review is presented of the possible impact of the corrosion of a copper supercontainer shell on the performance of the bentonite buffer. The review is presented in two parts; first an assessment of the likely corrosion behaviour of the copper shell, including an assessment of the amount and speciation of copper corrosion products, and, second an assessment of the possible interactions of these copper corrosion products with the bentonite and the consequences for the buffer performance. The corrosion behaviour of oxygen-free copper in compacted bentonite is reviewed, including the effects of a possible lower-density region at the buffer-rock interface initially. Corrosion occurs under both aerobic conditions, due to the initial O 2 trapped in the bentonite and O 2 in the air or water-filled gap at the buffer/rock interface, and anaerobic conditions, due to sulphide present in the groundwater and that possibly produced by microbial activity in the bentonite. The reaction mechanism, the nature of the dissolved and precipitated corrosion products, and the evolution of the corrosion behaviour with time are discussed with reference to groundwater conditions at both Olkiluoto and Forsmark. Various interactions between the copper corrosion products (Cu(II) and Cu(I) species) and bentonite are considered, including diffusion and sorption and the incorporation of Cu into the bentonite. The available literature information on these processes is first reviewed and then this knowledge is used to predict the likely behaviour in a KBS-3H-style repository. Based on the information currently available, it is concluded that the corrosion of a copper supercontainer shell will only affect the bentonite within a distance of a few cm of the original location of the shell. Eventually, the copper shell will corrode to form an insoluble precipitate layer of Cu 2 S approximately 2-3 times the volume of the original shell. Bentonite within a few cm of this layer of precipitate may also

Vulnerability of the paper Nautilus (Argonauta nodosa) shell to a climate-change ocean: potential for extinction by dissolution.

Science.gov (United States)

Wolfe, Kennedy; Smith, Abigail M; Trimby, Patrick; Byrne, Maria

2012-10-01

Shell calcification in argonauts is unique. Only females of these cephalopods construct the paper nautilus shell, which is used as a brood chamber for developing embryos in the pelagic realm. As one of the thinnest (225 μm) known adult mollusc shells, and lacking an outer protective periostracum-like cover, this shell may be susceptible to dissolution as the ocean warms and decreases in pH. Vulnerability of the A. nodosa shell was investigated through immersion of shell fragments in multifactorial experiments of control (19 °C/pH 8.1; pCO(2) 419; Ω(Ca) = 4.23) and near-future conditions (24 °C/pH 7.8-7.6; pCO(2) 932-1525; Ω(Ca) = 2.72-1.55) for 14 days. More extreme pH treatments (pH 7.4-7.2; pCO(2) 2454-3882; Ω(Ca) = 1.20-0.67) were used to assess tipping points in shell dissolution. X-ray diffractometry revealed no change in mineralogy between untreated and treated shells. Reduced shell weight due to dissolution was evident in shells incubated at pH 7.8 (projected for 2070) after 14 days at control temperature, with increased dissolution in warmer and lower pH treatments. The greatest dissolution was recorded at 24 °C (projected for local waters by 2100) compared to control temperature across all low-pH treatments. Scanning electron microscopy revealed dissolution and etching of shell mineral in experimental treatments. In the absence of compensatory mineralization, the uncovered female brood chamber will be susceptible to dissolution as ocean pH decreases. Since the shell was a crucial adaptation for the evolution of the argonauts' holopelagic existence, persistence of A. nodosa may be compromised by shell dissolution in an ocean-change world.

Enhanced thermoelectric transport in modulation-doped GaN/AlGaN core/shell nanowires

International Nuclear Information System (INIS)

Song, Erdong; Martinez, Julio A; Li, Qiming; Pan, Wei; Wang, George T; Swartzentruber, Brian

2016-01-01

The thermoelectric properties of unintentionally n-doped core GaN/AlGaN core/shell N-face nanowires are reported. We found that the temperature dependence of the electrical conductivity is consistent with thermally activated carriers with two distinctive donor energies. The Seebeck coefficient of GaN/AlGaN nanowires is more than twice as large as that for the GaN nanowires alone. However, an outer layer of GaN deposited onto the GaN/AlGaN core/shell nanowires decreases the Seebeck coefficient at room temperature, while the temperature dependence of the electrical conductivity remains the same. We attribute these observations to the formation of an electron gas channel within the heavily-doped GaN core of the GaN/AlGaN nanowires. The room-temperature thermoelectric power factor for the GaN/AlGaN nanowires can be four times higher than the GaN nanowires. Selective doping in bandgap engineered core/shell nanowires is proposed for enhancing the thermoelectric power. (paper)

Hydrazine-Assisted Formation of Indium Phosphide (InP)-Based Nanowires and Core-Shell Composites.

Science.gov (United States)

Patzke, Greta R; Kontic, Roman; Shiolashvili, Zeinab; Makhatadze, Nino; Jishiashvili, David

2012-12-27

Indium phosphide nanowires (InP NWs) are accessible at 440 °C from a novel vapor phase deposition approach from crystalline InP sources in hydrazine atmospheres containing 3 mol % H₂O. Uniform zinc blende (ZB) InP NWs with diameters around 20 nm and lengths up to several tens of micrometers are preferably deposited on Si substrates. InP particle sizes further increase with the deposition temperature. The straightforward protocol was extended on the one-step formation of new core-shell InP-Ga NWs from mixed InP/Ga source materials. Composite nanocables with diameters below 20 nm and shells of amorphous gallium oxide are obtained at low deposition temperatures around 350 °C. Furthermore, InP/Zn sources afford InP NWs with amorphous Zn/P/O-coatings at slightly higher temperatures (400 °C) from analogous setups. At 450 °C, the smooth outer layer of InP-Zn NWs is transformed into bead-shaped coatings. The novel combinations of the key semiconductor InP with isotropic insulator shell materials open up interesting application perspectives in nanoelectronics.

Comparative study on thermal performance of natural draft cooling towers with finned shells

International Nuclear Information System (INIS)

Goodarzi, Mohsen

2016-01-01

The cooling efficiency of natural draft cooling towers under crosswind condition should be improved. In the present research work three different externally finned shells were considered for a typical natural draft cooling tower to investigate the cooling improvement. They were numerically simulated under normal and crosswind conditions. Numerical results show that twisting four fin plates over the tower shell along the 45 peripheral angle, could improve the cooling efficiency up to 6.5 %. Because of the periodic shape of the fin plates, the cooling efficiency of the cooling tower with finned shell is less sensitive to the change of wind.

Comparative study on thermal performance of natural draft cooling towers with finned shells

Energy Technology Data Exchange (ETDEWEB)

Goodarzi, Mohsen [Bu-Ali Sina Univ., Hamedan (Iran, Islamic Republic of). Dept. of Mechanical Engineering

2016-10-15

The cooling efficiency of natural draft cooling towers under crosswind condition should be improved. In the present research work three different externally finned shells were considered for a typical natural draft cooling tower to investigate the cooling improvement. They were numerically simulated under normal and crosswind conditions. Numerical results show that twisting four fin plates over the tower shell along the 45 peripheral angle, could improve the cooling efficiency up to 6.5 %. Because of the periodic shape of the fin plates, the cooling efficiency of the cooling tower with finned shell is less sensitive to the change of wind.

Radar attenuation in Europa's ice shell: Obstacles and opportunities for constraining the shell thickness and its thermal structure

Science.gov (United States)

Kalousová, Klára; Schroeder, Dustin M.; Soderlund, Krista M.

2017-03-01

Young surface and possible recent endogenic activity make Europa one of the most exciting solar system bodies and a primary target for spacecraft exploration. Future Europa missions are expected to carry ice-penetrating radar instruments designed to investigate its subsurface thermophysical structure. Several authors have addressed the radar sounders' performance at icy moons, often ignoring the complex structure of a realistic ice shell. Here we explore the variation in two-way radar attenuation for a variety of potential thermal structures of Europa's shell (determined by reference viscosity, activation energy, tidal heating, surface temperature, and shell thickness) as well as for low and high loss temperature-dependent attenuation model. We found that (i) for all investigated ice shell thicknesses (5-30 km), the radar sounder will penetrate between 15% and 100% of the total thickness, (ii) the maximum penetration depth varies laterally, with deepest penetration possible through cold downwellings, (iii) direct ocean detection might be possible for shells of up to 15 km thick if the signal travels through cold downwelling ice or the shell is conductive, (iv) even if the ice/ocean interface is not directly detected, penetration through most of the shell could constrain the deep shell structure through returns from deep non-ocean interfaces or the loss of signal itself, and (v) for all plausible ice shells, the two-way attenuation to the eutectic point is ≲30 dB which shows a robust potential for longitudinal investigation of the ice shell's shallow thermophysical structure.

Structure, energetic and phase transition of multi shell icosahedral bimetallic nanostructures: A molecular dynamics study of NimPdn (n + m = 55 and 147)

International Nuclear Information System (INIS)

Hewage, Jinasena W.

2015-01-01

Structure, energetic and thermodynamic properties of multi shell icosahedral bimetallic nickel–palladium nanostructures with the size of 55 and 147 atoms were studied by using the molecular dynamics simulations and the microcanonical ensemble version of multiple histogram method. In 55 atoms icosahedra, two core–shell motifs, Ni 13 Pd 42 and Pd 13 Ni 42 with their isomers Pd 13 (Pd 29 Ni 13 ) and Ni 13 (Ni 29 Pd 13 ) were considered. Similarly in 147 atoms icosahedra, all mutations corresponding to the occupations of either nickel atoms or palladium atoms in the core, inner shell or outer shell and their isomers generated by interchanging thirteen core atoms with thirteen atoms of the other type in the inner and outer shells were considered. It is found that the nickel-core clusters are more stable than the palladium-core clusters and cohesive energy increases with the nickel composition. Phase transition of each cluster was studied by means of constant volume heat capacity. The trend in variation of melting temperature is opposite to the energy trend and special increase in melting points was observed for nickel-core isomers compared to the palladium-core isomers. Helmholtz free energy change with temperature for shell to core interchange of thirteen atoms revealed the thermodynamic stability of the formation of Ni core Pd shell structures and the surface segregation of palladium. - Highlights: • Nanostructures of Ni m Pd n clusters for m + n = 55 and 147 have been studied. • Structures favor the formation of nickel-core surrounded by palladium atoms. • In general, it appears the increase of cohesive energy with the nickel composition. • Calculated thermodynamic parameters confirm the energetic results. • Results show also the palladium segregation on the surface

Hierarchical core-shell structure of ZnO nanorod@NiO/MoO₂ composite nanosheet arrays for high-performance supercapacitors.

Science.gov (United States)

Hou, Sucheng; Zhang, Guanhua; Zeng, Wei; Zhu, Jian; Gong, Feilong; Li, Feng; Duan, Huigao

2014-08-27

A hierarchical core-shell structure of ZnO nanorod@NiO/MoO2 composite nanosheet arrays on nickel foam substrate for high-performance supercapacitors was constructed by a two-step solution-based method involving two hydrothermal processes followed by a calcination treatment. Compared to one composed of pure NiO/MoO2 composite nanosheets, the hierarchical core-shell structure electrode displays better pseudocapacitive behaviors in 2 M KOH, including high areal specific capacitance values of 1.18 F cm(-2) at 5 mA cm(-2) and 0.6 F cm(-2) at 30 mA cm(-2) as well as relatively good rate capability at high current densities. Furthermore, it also shows remarkable cycle stability, remaining at 91.7% of the initial value even after 4000 cycles at a current density of 10 mA cm(-2). The enhanced pseudocapacitive behaviors are mainly due to the unique hierarchical core-shell structure and the synergistic effect of combining ZnO nanorod arrays and NiO/MoO2 composite nanosheets. This novel hierarchical core-shell structure shows promise for use in next-generation supercapacitors.

Inner-shell vacancy production and multiple ionization effects in 0.1-1.75 MeV/u Mn, Fe, Co, Ni, Cu + Au, Bi collisions

Energy Technology Data Exchange (ETDEWEB)

Ciortea, C. E-mail: ciortea@tandem.nipne.ro; Piticu, I.; Dumitriu, D.E.; Fluerasu, D.; Enulescu, A.; Szilagyi, S.Z.; Enescu, S.E.; Gugiu, M.M.; Dumitrescu, T.A

2003-05-01

Vacancy production in 0.1-1.75 MeV/u Mn, Fe, Co, Ni, Cu + Au, Bi collisions has been studied by measuring integral inner-shell ionization cross-sections and mean outer-shell ionization probabilities at the Tandem accelerator of NIPNE, Bucharest. X-ray spectra induced by ion beams of Mn, Fe, Co, Ni and Cu impinging on thin solid-foil targets of Au and Bi have been measured. Total ionization cross-sections for the K-shell of the projectile and L{sub 3}-subshell of the target, as well as vacancy sharing probabilities, corrected for the effect of multiple ionization, are reported. The experimental results are discussed in terms of two model calculations.

Optical properties of core-shell and multi-shell nanorods

Science.gov (United States)

Mokkath, Junais Habeeb; Shehata, Nader

2018-05-01

We report a first-principles time dependent density functional theory study of the optical response modulations in bimetallic core-shell (Na@Al and Al@Na) and multi-shell (Al@Na@Al@Na and Na@Al@Na@Al: concentric shells of Al and Na alternate) nanorods. All of the core-shell and multi-shell configurations display highly enhanced absorption intensity with respect to the pure Al and Na nanorods, showing sensitivity to both composition and chemical ordering. Remarkably large spectral intensity enhancements were found in a couple of core-shell configurations, indicative that optical response averaging based on the individual components can not be considered as true as always in the case of bimetallic core-shell nanorods. We believe that our theoretical results would be useful in promising applications depending on Aluminum-based plasmonic materials such as solar cells and sensors.

CO{sub 2} capture behavior of shell during calcination/carbonation cycles

Energy Technology Data Exchange (ETDEWEB)

Li, Y.J.; Zhao, C.S.; Chen, H.C.; Duan, L.B.; Chen, X.P. [School of Energy and Environment, Southeast University, Nanjing (China)

2009-08-15

The cyclic carbonation performances of shells as CO{sub 2} sorbents were investigated during multiple calcination/carbonation cycles. The carbonation kinetics of the shell and limestone are similar since they both exhibit a fast kinetically controlled reaction regime and a diffusion controlled reaction regime, but their carbonation rates differ between these two regions. Shell achieves the maximum carbonation conversion for carbonation at 680-700 C. The mactra veneriformis shell and mussel shell exhibit higher carbonation conversions than limestone after several cycles at the same reaction conditions. The carbonation conversion of scallop shell is slightly higher than that of limestone after a series of cycles. The calcined shell appears more porous than calcined limestone, and possesses more pores >230 nm, which allow large CO{sub 2} diffusion-carbonation reaction rates and higher conversion due to the increased surface area of the shell. The pores of the shell that are greater than 230 nm do not sinter significantly. The shell has more sodium ions than limestone, which probably leads to an improvement in the cyclic carbonation performance during the multiple calcination/carbonation cycles. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Shell structure of natural rubber particles: evidence of chemical stratification by electrokinetics and cryo-TEM.

Science.gov (United States)

Rochette, Christophe N; Crassous, Jérôme J; Drechsler, Markus; Gaboriaud, Fabien; Eloy, Marie; de Gaudemaris, Benoît; Duval, Jérôme F L

2013-11-26

The interfacial structure of natural rubber (NR) colloids is investigated by means of cryogenic transmission electron microscopy (cryo-TEM) and electrokinetics over a broad range of KNO3 electrolyte concentrations (4-300 mM) and pH values (1-8). The asymptotic plateau value reached by NR electrophoretic mobility (μ) in the thin double layer limit supports the presence of a soft (ion- and water-permeable) polyelectrolytic type of layer located at the periphery of the NR particles. This property is confirmed by the analysis of the electron density profile obtained from cryo-TEM that evidences a ∼2-4 nm thick corona surrounding the NR polyisoprene core. The dependence of μ on pH and salt concentration is further marked by a dramatic decrease of the point of zero electrophoretic mobility (PZM) from 3.6 to 0.8 with increasing electrolyte concentration in the range 4-300 mM. Using a recent theory for electrohydrodynamics of soft multilayered particles, this "anomalous" dependence of the PZM on electrolyte concentration is shown to be consistent with a radial organization of anionic and cationic groups across the peripheral NR structure. The NR electrokinetic response in the pH range 1-8 is indeed found to be equivalent to that of particles surrounded by a positively charged ∼3.5 nm thick layer (mean dissociation pK ∼ 4.2) supporting a thin and negatively charged outermost layer (0.6 nm in thickness, pK ∼ 0.7). Altogether, the strong dependence of the PZM on electrolyte concentration suggests that the electrostatic properties of the outer peripheral region of the NR shell are mediated by lipidic residues protruding from a shell containing a significant amount of protein-like charges. This proposed NR shell interfacial structure questions previously reported NR representations according to which the shell consists of either a fully mixed lipid-protein layer, or a layer of phospholipids residing exclusively beneath an outer proteic film.

Turbine airfoil with outer wall thickness indicators

Science.gov (United States)

Marra, John J; James, Allister W; Merrill, Gary B

2013-08-06

A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

Recent shell-model results for exotic nuclei

Directory of Open Access Journals (Sweden)

Utsuno Yusuke

2014-03-01

Full Text Available We report on our recent advancement in the shell model and its applications to exotic nuclei, focusing on the shell evolution and large-scale calculations with the Monte Carlo shell model (MCSM. First, we test the validity of the monopole-based universal interaction (VMU as a shell-model interaction by performing large-scale shell-model calculations in two different mass regions using effective interactions which partly comprise VMU. Those calculations are successful and provide a deeper insight into the shell evolution beyond the single-particle model, in particular showing that the evolution of the spin-orbit splitting due to the tensor force plays a decisive role in the structure of the neutron-rich N ∼ 28 region and antimony isotopes. Next, we give a brief overview of recent developments in MCSM, and show that it is applicable to exotic nuclei that involve many valence orbits. As an example of its applications to exotic nuclei, shape coexistence in 32Mg is examined.

Containers and systems for the measurement of radioactive gases and related methods

Science.gov (United States)

Mann, Nicholas R; Watrous, Matthew G; Oertel, Christopher P; McGrath, Christopher A

2017-06-20

Containers for a fluid sample containing a radionuclide for measurement of radiation from the radionuclide include an outer shell having one or more ports between an interior and an exterior of the outer shell, and an inner shell secured to the outer shell. The inner shell includes a detector receptacle sized for at least partial insertion into the outer shell. The inner shell and outer shell together at least partially define a fluid sample space. The outer shell and inner shell are configured for maintaining an operating pressure within the fluid sample space of at least about 1000 psi. Systems for measuring radioactivity in a fluid include such a container and a radiation detector received at least partially within the detector receptacle. Methods of measuring radioactivity in a fluid sample include maintaining a pressure of a fluid sample within a Marinelli-type container at least at about 1000 psi.

Phase-pure β-NiMoO4 yolk-shell spheres for high-performance anode materials in lithium-ion batteries

International Nuclear Information System (INIS)

Ahn, Jee Hyun; Park, Gi Dae; Kang, Yun Chan; Lee, Jong-Heun

2015-01-01

Phase-pure β-NiMoO 4 yolk-shell spheres for lithium-ion battery anodes were prepared for the first time by one-pot spray pyrolysis, and their electrochemical properties were investigated. The yolk-shell-structured β-NiMoO 4 powders exhibited high initial discharge/charge capacities (1634/1253 mA h g −1 ) at a current density of 1000 mA g −1 . After 200 cycles, these powders exhibited a high discharge capacity of 1292 mA h g −1 , whereas the initial discharge capacity (1341 mA h g −1 ) of the filled structured NiMoO 4 powders was dramatically decreased to 479 mA h g −1 . The significant enhancement of the cycling performance of the β-NiMoO 4 powders with ultrafine crystallite size was attributed to the structural stability of the yolk-shell structure

Photoionization cross section and binding energy of single dopant in hollow cylindrical core/shell quantum dot

Science.gov (United States)

Feddi, E.; El-Yadri, M.; Dujardin, F.; Restrepo, R. L.; Duque, C. A.

2017-02-01

In this study, we have investigated the confined donor impurity in a hollow cylindrical-shell quantum dot. The charges are assumed to be completely confined to the interior of the shell with rigid walls. Within the framework of the effective-mass approximation and by using a simple variational approach, we have computed the donor binding energy as a function of the shell sizes in order to study the behavior of the electron-impurity attraction for a very small thickness. Our results show that the binding energy of a donor impurity placed at the center of cylindrical core/shell dots depends strongly on the shell size. The binding energy increases when the shell-wideness becomes smaller and shows the same behavior as in a simple cylindrical quantum dot. A special case has been studied, which corresponds to the ratio between the inner and outer radii near to one (a/b → 1) for which our model gives a non-significant behavior of the impurity binding energy. This fact implies the existence of a critical value (a/b) for which the binding energy of the donor impurity tends to the limit value of 4 effective Rydbergs as in a 2D quantum well. We also analyse the photoionization cross section considering only the in-plane incident radiation polarization. We determine its behavior as a function of photon energy, shell size, and donor position. The measurement of photoionization in such systems would be of great interest to understand the optical properties of carriers in quantum dots.

Smart construction of polyaniline shell on cobalt oxides as integrated core-shell arrays for enhanced lithium ion batteries

International Nuclear Information System (INIS)

Qi, Meili; Xie, Dong; Zhong, Yu; Chen, Minghua; Xia, Xinhui

2017-01-01

Smart construction of advanced anode materials is extremely critical to develop high-performance lithium ion batteries. In this work, we have reported a facile strategy for fabricating Co 3 O 4 /polyaniline (PANI) core–shell arrays (CSAs) by chemical bath deposition (CBD) + electrodeposition methods Electrodeposited PANI shell is intimately decorated on the CBD-Co 3 O 4 nanorods forming composite CSAs. Highly conductive network and stress buffer layer are achieved with the aid of tailored PANI shell. Due to these advantages above, the designed Co 3 O 4 /PANI CSA S exhibit good electrochemical performance with higher reversible capacity (787 mAh g −1 ) and better cycle stability than the unmodified Co 3 O 4 counterpart. Our results show a new way for preparing advanced inorganic-organic composite electrodes for electrochemical energy storage.

Design and economic investigation of shell and tube heat exchangers using Improved Intelligent Tuned Harmony Search algorithm

Directory of Open Access Journals (Sweden)

Oguz Emrah Turgut

2014-12-01

Full Text Available This study explores the thermal design of shell and tube heat exchangers by using Improved Intelligent Tuned Harmony Search (I-ITHS algorithm. Intelligent Tuned Harmony Search (ITHS is an upgraded version of harmony search algorithm which has an advantage of deciding intensification and diversification processes by applying proper pitch adjusting strategy. In this study, we aim to improve the search capacity of ITHS algorithm by utilizing chaotic sequences instead of uniformly distributed random numbers and applying alternative search strategies inspired by Artificial Bee Colony algorithm and Opposition Based Learning on promising areas (best solutions. Design variables including baffle spacing, shell diameter, tube outer diameter and number of tube passes are used to minimize total cost of heat exchanger that incorporates capital investment and the sum of discounted annual energy expenditures related to pumping and heat exchanger area. Results show that I-ITHS can be utilized in optimizing shell and tube heat exchangers.

Vibrational analysis of submerged cylindrical shells based on elastic foundations

International Nuclear Information System (INIS)

Shah, A.G.; Naeem, M.N.

2014-01-01

In this study a vibration analysis was performed of an isotropic cylindrical shell submerged in fluid, resting on Winkler and Pasternak elastic foundations for simply supported boundary condition. Love's thin shell theory was exploited for strain- and curvature- displacement relationship. Shell problem was solved by using wave propagation approach. Influence of fluid and Winkler as well as Pasternak elastic foundations were studied on the natural frequencies of submerged isotropic cylindrical shells. Results were validated by comparing with the existing results in literature. Vibration, Submerged cylindrical shell, Love's thin shell theory, Wave propagation method, Winkler and Pasternak foundations. (author)

Turbine airfoil with a compliant outer wall

Science.gov (United States)

Campbell, Christian X [Oviedo, FL; Morrison, Jay A [Oviedo, FL

2012-04-03

A turbine airfoil usable in a turbine engine with a cooling system and a compliant dual wall configuration configured to enable thermal expansion between inner and outer layers while eliminating stress formation in the outer layer is disclosed. The compliant dual wall configuration may be formed a dual wall formed from inner and outer layers separated by a support structure. The outer layer may be a compliant layer configured such that the outer layer may thermally expand and thereby reduce the stress within the outer layer. The outer layer may be formed from a nonplanar surface configured to thermally expand. In another embodiment, the outer layer may be planar and include a plurality of slots enabling unrestricted thermal expansion in a direction aligned with the outer layer.

An ochered fossil marine shell from the mousterian of fumane cave, Italy.

Directory of Open Access Journals (Sweden)

Marco Peresani

Full Text Available A scanty but varied ensemble of finds challenges the idea that Neandertal material culture was essentially static and did not include symbolic items. In this study we report on a fragmentary Miocene-Pliocene fossil marine shell, Aspamarginata, discovered in a Discoid Mousterian layer of the Fumane Cave, northern Italy, dated to at least 47.6-45.0 Cal ky BP. The shell was collected by Neandertals at a fossil exposure probably located more than 100 kms from the site. Microscopic analysis of the shell surface identifies clusters of striations on the inner lip. A dark red substance, trapped inside micropits produced by bioeroders, is interpreted as pigment that was homogeneously smeared on the outer shell surface. Dispersive X-ray and Raman analysis identify the pigment as pure hematite. Of the four hypotheses we considered to explain the presence of this object at the site, two (tool, pigment container are discarded because in contradiction with observations. Although the other two ("manuport", personal ornament are both possible, we favor the hypothesis that the object was modified and suspended by a 'thread' for visual display as a pendant. Together with contextual and chronometric data, our results support the hypothesis that deliberate transport and coloring of an exotic object, and perhaps its use as pendant, was a component of Neandertal symbolic culture, well before the earliest appearance of the anatomically modern humans in Europe.

Construction of Core-Shell NiMoO4@Ni-Co-S Nanorods as Advanced Electrodes for High-Performance Asymmetric Supercapacitors.

Science.gov (United States)

Chen, Chao; Yan, Dan; Luo, Xin; Gao, Wenjia; Huang, Guanjie; Han, Ziwu; Zeng, Yan; Zhu, Zhihong

2018-02-07

In this work, hierarchical core-shell NiMoO 4 @Ni-Co-S nanorods were first successfully grown on nickel foam by a facile two-step method to fabricate a bind-free electrode. The well-aligned electrode wrapped by Ni-Co-S nanosheets displays excellent nanostructural properties and outstanding electrochemical performance, owing to the synergistic effects of both nickel molybdenum oxides and nickel cobalt sulfides. The prepared core-shell nanorods in a three-electrode cell yielded a high specific capacitance of 2.27 F cm -2 (1892 F g -1 ) at a current density of 5 mA cm -2 and retained 91.7% of the specific capacitance even after 6000 cycles. Their electrochemical performance was further investigated for their use as positive electrode for asymmetric supercapacitors. Notably, the energy density of the asymmetric supercapacitor device reached 2.45 mWh cm -3 at a power density of 0.131 W cm -3 , and still retained a remarkable 80.3% of the specific capacitance after 3500 cycles. There is great potential for the electrode composed of the core-shell NiMoO 4 @Ni-Co-S nanorods for use in an all-solid-state asymmetric supercapacitor device.

LHCb: The Performance and Radiation Hardness of the Outer Tracker Detector for LHCb

CERN Multimedia

Färber, C

2012-01-01

The LHC bexperiment is designed to study B-decays at the LHC. It is crucial to accurately and efficiently detect the charged decay particles in the high-density particle environment of the LHC. For this, the Outer Tracker (OT) has been constructed, consisting of 53,760 straw tubes, covering in total an area of 360 m2 of double layers. At the time of the conference, the detector will have operated under nominal LHC conditions for a period of about 2 years, corresponding to an integrated luminosity of approximately 2.5 fb$^{-1}$ . The performance of the detector will be discussed in terms of high voltage stability, noise rate, single hit efficiency and resolution. Finally, first results on the radiation tolerance of this sensitive gas detector will be shown, after having received a total dose corresponding to about 100 mC/cm in the hottest region.

The Outer Space Treaty

Science.gov (United States)

Johnson, Christopher Daniel

2018-01-01

Negotiated at the United Nations and in force since 1967, the Outer Space Treaty has been ratified by over 100 countries and is the most important and foundational source of space law. The treaty, whose full title is "Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies," governs all of humankind's activities in outer space, including activities on other celestial bodies and many activities on Earth related to outer space. All space exploration and human spaceflight, planetary sciences, and commercial uses of space—such as the global telecommunications industry and the use of space technologies such as position, navigation, and timing (PNT), take place against the backdrop of the general regulatory framework established in the Outer Space Treaty. A treaty is an international legal instrument which balances rights and obligations between states, and exists as a kind of mutual contract of shared understandings, rights, and responsibilities between them. Negotiated and drafted during the Cold War era of heightened political tensions, the Outer Space Treaty is largely the product of efforts by the United States and the USSR to agree on certain minimum standards and obligations to govern their competition in "conquering" space. Additionally, the Outer Space Treaty is similar to other treaties, including treaties governing the high seas, international airspace, and the Antarctic, all of which govern the behavior of states outside of their national borders. The treaty is brief in nature and only contains 17 articles, and is not comprehensive in addressing and regulating every possible scenario. The negotiating states knew that the Outer Space Treaty could only establish certain foundational concepts such as freedom of access, state responsibility and liability, non-weaponization of space, the treatment of astronauts in distress, and the prohibition of non-appropriation of

Electrosprayed core–shell solid dispersions of acyclovir fabricated using an epoxy-coated concentric spray head

Science.gov (United States)

Liu, Zhe-Peng; Cui, Lei; Yu, Deng-Guang; Zhao, Zhuan-Xia; Chen, Lan

2014-01-01

A novel structural solid dispersion (SD) taking the form of core–shell microparticles for poorly water-soluble drugs is reported for the first time. Using polyvinylpyrrolidone (PVP) as a hydrophilic polymer matrix, the SDs were fabricated using coaxial electrospraying (characterized by an epoxy-coated concentric spray head), although the core fluids were unprocessable using one-fluid electrospraying. Through manipulating the flow rates of the core drug-loaded solutions, two types of core–shell microparticles with tunable drug contents were prepared. They had average diameters of 1.36±0.67 and 1.74±0.58 μm, and were essentially a combination of nanocomposites with the active ingredient acyclovir (ACY) distributed in the inner core, and the sweeter sucralose and transmembrane enhancer sodium dodecyl sulfate localized in the outer shell. Differential scanning calorimetry and X-ray diffraction results demonstrated that ACY, sodium dodecyl sulfate, and sucralose were well distributed in the PVP matrix in an amorphous state because of favorable second-order interactions. In vitro dissolution and permeation studies showed that the core–shell microparticle SDs rapidly freed ACY within 1 minute and promoted nearly eightfold increases in permeation rate across the sublingual mucosa compared with raw ACY powders. PMID:24790437

Magnetic and fluorescent core-shell nanoparticles for ratiometric pH sensing

International Nuclear Information System (INIS)

Lapresta-Fernandez, Alejandro; Doussineau, Tristan; Moro, Artur J; Dutz, Silvio; Steiniger, Frank; Mohr, Gerhard J

2011-01-01

This paper describes the preparation of nanoparticles composed of a magnetic core surrounded by two successive silica shells embedding two fluorophores, showing uniform nanoparticle size (50-60 nm in diameter) and shape, which allow ratiometric pH measurements in the pH range 5-8. Uncoated iron oxide magnetic nanoparticles (∼10 nm in diameter) were formed by the coprecipitation reaction of ferrous and ferric salts. Then, they were added to a water-in-oil microemulsion where the hydrophilic silica shells were obtained through hydrolysis and condensation of tetraethoxyorthosilicate together with the corresponding silylated dye derivatives-a sulforhodamine was embedded in the inner silica shell and used as the reference dye while a pH-sensitive fluorescein was incorporated in the outer shell as the pH indicator. The magnetic nanoparticles were characterized using vibrating sample magnetometry, dynamic light scattering, transmission electron microscopy, x-ray diffraction and Fourier transform infrared spectroscopy. The relationship between the analytical parameter, that is, the ratio of fluorescence between the sensing and reference dyes versus the pH was adjusted to a sigmoidal fit using a Boltzmann type equation giving an apparent pK a value of 6.8. The fluorescence intensity of the reference dye did not change significantly (∼3.0%) on modifying the pH of the nanoparticle dispersion. Finally, the proposed method was statistically validated against a reference procedure using samples of water and physiological buffer with 2% of horse serum, indicating that there are no significant statistical differences at a 95% confidence level.

Deriving the nuclear shell model from first principles

Science.gov (United States)

Barrett, Bruce R.; Dikmen, Erdal; Vary, James P.; Maris, Pieter; Shirokov, Andrey M.; Lisetskiy, Alexander F.

2014-09-01

The results of an 18-nucleon No Core Shell Model calculation, performed in a large basis space using a bare, soft NN interaction, can be projected into the 0 ℏω space, i.e., the sd -shell. Because the 16 nucleons in the 16O core are frozen in the 0 ℏω space, all the correlations of the 18-nucleon system are captured by the two valence, sd -shell nucleons. By the projection, we obtain microscopically the sd -shell 2-body effective interactions, the core energy and the sd -shell s.p. energies. Thus, the input for standard shell-model calculations can be determined microscopically by this approach. If the same procedure is then applied to 19-nucleon systems, the sd -shell 3-body effective interactions can also be obtained, indicating the importance of these 3-body effective interactions relative to the 2-body effective interactions. Applications to A = 19 and heavier nuclei with different intrinsic NN interactions will be presented and discussed. The results of an 18-nucleon No Core Shell Model calculation, performed in a large basis space using a bare, soft NN interaction, can be projected into the 0 ℏω space, i.e., the sd -shell. Because the 16 nucleons in the 16O core are frozen in the 0 ℏω space, all the correlations of the 18-nucleon system are captured by the two valence, sd -shell nucleons. By the projection, we obtain microscopically the sd -shell 2-body effective interactions, the core energy and the sd -shell s.p. energies. Thus, the input for standard shell-model calculations can be determined microscopically by this approach. If the same procedure is then applied to 19-nucleon systems, the sd -shell 3-body effective interactions can also be obtained, indicating the importance of these 3-body effective interactions relative to the 2-body effective interactions. Applications to A = 19 and heavier nuclei with different intrinsic NN interactions will be presented and discussed. Supported by the US NSF under Grant No. 0854912, the US DOE under

Nanomechanics of biocompatible hollow thin-shell polymer microspheres.

Science.gov (United States)

Glynos, Emmanouil; Koutsos, Vasileios; McDicken, W Norman; Moran, Carmel M; Pye, Stephen D; Ross, James A; Sboros, Vassilis

2009-07-07

The nanomechanical properties of biocompatible thin-shell hollow polymer microspheres with approximately constant ratio of shell thickness to microsphere diameter were measured by nanocompression tests in aqueous conditions. These microspheres encapsulate an inert gas and are used as ultrasound contrast agents by releasing free microbubbles in the presence of an ultrasound field as a result of free gas leakage from the shell. The tests were performed using an atomic force microscope (AFM) employing the force-distance curve technique. An optical microscope, on which the AFM was mounted, was used to guide the positioning of tipless cantilevers on top of individual microspheres. We performed a systematic study using several cantilevers with spring constants varying from 0.08 to 2.3 N/m on a population of microspheres with diameters from about 2 to 6 microm. The use of several cantilevers with various spring constants allowed a systematic study of the mechanical properties of the microsphere thin shell at different regimes of force and deformation. Using thin-shell mechanics theory for small deformations, the Young's modulus of the thin wall material was estimated and was shown to exhibit a strong size effect: it increased as the shell became thinner. The Young's modulus of thicker microsphere shells converged to the expected value for the macroscopic bulk material. For high applied forces, the force-deformation profiles showed a reversible and/or irreversible nonlinear behavior including "steps" and "jumps" which were attributed to mechanical instabilities such as buckling events.

Meta-shell Approach for Constructing Lightweight and High Resolution X-Ray Optics

Science.gov (United States)

McClelland, Ryan S.

2016-01-01

Lightweight and high resolution optics are needed for future space-based x-ray telescopes to achieve advances in high-energy astrophysics. Past missions such as Chandra and XMM-Newton have achieved excellent angular resolution using a full shell mirror approach. Other missions such as Suzaku and NuSTAR have achieved lightweight mirrors using a segmented approach. This paper describes a new approach, called meta-shells, which combines the fabrication advantages of segmented optics with the alignment advantages of full shell optics. Meta-shells are built by layering overlapping mirror segments onto a central structural shell. The resulting optic has the stiffness and rotational symmetry of a full shell, but with an order of magnitude greater collecting area. Several meta-shells so constructed can be integrated into a large x-ray mirror assembly by proven methods used for Chandra and XMM-Newton. The mirror segments are mounted to the meta-shell using a novel four point semi-kinematic mount. The four point mount deterministically locates the segment in its most performance sensitive degrees of freedom. Extensive analysis has been performed to demonstrate the feasibility of the four point mount and meta-shell approach. A mathematical model of a meta-shell constructed with mirror segments bonded at four points and subject to launch loads has been developed to determine the optimal design parameters, namely bond size, mirror segment span, and number of layers per meta-shell. The parameters of an example 1.3 m diameter mirror assembly are given including the predicted effective area. To verify the mathematical model and support opto-mechanical analysis, a detailed finite element model of a meta-shell was created. Finite element analysis predicts low gravity distortion and low thermal distortion. Recent results are discussed including Structural Thermal Optical Performance (STOP) analysis as well as vibration and shock testing of prototype meta-shells.

Hi shells, supershells, shell-like objects, and ''worms''

International Nuclear Information System (INIS)

Heiles, C.

1984-01-01

We present photographic representations of the combination of two Hi surveys, so as to eliminate the survey boundaries at Vertical BarbVertical Bar = 10 0 . We also present high-contrast photographs for particular velocities to exhibit weak Hi features. All of these photographs were used to prepare a new list of Hi shells, supershells, and shell-like objects. We discuss the structure of three shell-like objects that are associated with high-velocity gas, and with gas at all velocities that is associated with radio continuum loops I, II, and III. We use spatial filtering to find wiggly gas filaments: ''worms'': crawling away from the galactic plane in the inner Galaxy. The ''worms'' are probably parts of shells that are open at the top; such shells should be good sources of hot gas for the galactic halo

Facile synthesis of core–shell structured PANI-Co{sub 3}O{sub 4} nanocomposites with superior electrochemical performance in supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Hai, Zhenyin [Key Laboratory of Instrumentation and Dynamic Measurement of Ministry of Education, North University of China, Taiyuan, Shanxi 030051 (China); Gao, Libo [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong SAR, Kowloon 999077 (Hong Kong); Zhang, Qiang [Key Laboratory of Instrumentation and Dynamic Measurement of Ministry of Education, North University of China, Taiyuan, Shanxi 030051 (China); Xu, Hongyan [School of Materials Science and Engineering, North University of China, Taiyuan, Shanxi 030051 (China); Cui, Danfeng; Zhang, Zengxing [Key Laboratory of Instrumentation and Dynamic Measurement of Ministry of Education, North University of China, Taiyuan, Shanxi 030051 (China); Tsoukalas, Dimitris [Department of Applied Physics, National Technical University of Athens, Zografou GR-15780 (Greece); Tang, Jun; Yan, Shubin [Key Laboratory of Instrumentation and Dynamic Measurement of Ministry of Education, North University of China, Taiyuan, Shanxi 030051 (China); Xue, Chenyang, E-mail: xuechenyang@nuc.edu.cn [Key Laboratory of Instrumentation and Dynamic Measurement of Ministry of Education, North University of China, Taiyuan, Shanxi 030051 (China)

2016-01-15

Graphical abstract: - Highlights: • PANI-Co{sub 3}O{sub 4} is synthesized by carbon-assisted and in situ polymerization methods. • PANI coating improves the properties of Co{sub 3}O{sub 4} affecting electrochemical performance. • The nanocomposites exhibit a high specific capacitance of 1184 F g{sup −1} at 1.25 A g{sup −1}. - Abstract: Core–shell structured PANI-Co{sub 3}O{sub 4} nanocomposites for supercapacitor applications were synthesized by combination of carbon-assisted method and in situ polymerization method. The crystalline structure, optical band gap, morphology, and hydrophilic property, as the major factors affecting the performances of supercapacitors, were investigated by X-ray diffraction (XRD), UV–vis spectrophotometry (UV–vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and water contact angle (WCA). The core–shell structured PANI-Co{sub 3}O{sub 4} nanocomposites are characterized by amorphous PANI, small bandgaps, large surface area and favorable hydrophilicity, which indicates the superior electrochemical performances of the nanocomposites as electrode material for supercapacitors. Cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurements were conducted in 6 M KOH aqueous solution to evaluate the electrochemical performances. The results shows that core–shell structured PANI-Co{sub 3}O{sub 4} nanocomposites exhibit a high specific capacitance of 1184 F g{sup −1} at 1.25 A g{sup −1}, excellent cycling stability of a capacitance retention of 84.9% after 1000 galvanostatic charge/discharge cycles, good electrical conductivity and ion diffusion behavior.

Core@shell@shell structured carbon-based magnetic ternary nanohybrids: Synthesis and their enhanced microwave absorption properties

Science.gov (United States)

Yang, Erqi; Qi, Xiaosi; Xie, Ren; Bai, Zhongchen; Jiang, Yang; Qin, Shuijie; Zhong, Wei; Du, Youwei

2018-05-01

High encapsulation efficiency of core@shell@shell structured carbon-based magnetic ternary nanohybrids have been synthesized in high yield by chemical vapor deposition of acetylene directly over octahedral-shaped Fe2O3 nanoparticles. By controlling the pyrolysis temperature, Fe3O4@Fe3C@carbon nanotubes (CNTs) and Fe@Fe3C@CNTs ternary nanohybrids could be selectively produced. The optimal RL values for the as-prepared ternary nanohybrids could reach up to ca. -46.7, -52.7 and -29.5 dB, respectively. The excellent microwave absorption properties of the obtaiend ternary nanohybrids were proved to ascribe to the quarter-wavelength matching model. Moreover, the as-prepared Fe@Fe3C@CNTs ternary nanohybrids displayed remarkably enhanced EM wave absorption capabilities compared to Fe3O4@Fe3C@CNTs due to their excellent dielectric loss abilities, good complementarities between the dielectric loss and the magnetic loss, and high attenuation constant. Generally, this strategy can be extended to explore other categories of core@shell or core@shell@shell structured carbon-based nanohybrids, which is very beneficial to accelerate the advancements of high performance MAMs.

Nitrogen-doped porous “green carbon” derived from shrimp shell: Combined effects of pore sizes and nitrogen doping on the performance of lithium sulfur battery

Energy Technology Data Exchange (ETDEWEB)

Qu, Jiangying, E-mail: qujy@lnnu.edu.cn [Faculty of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian, 116029 (China); Carbon Research Laboratory, Center for Nano Materials and Science, School of Chemical Engineering, State Key Lab of Fine Chemicals, Dalian University of Technology, Dalian, 116024 (China); Lv, Siyuan; Peng, Xiyue; Tian, Shuo; Wang, Jia [Faculty of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian, 116029 (China); Gao, Feng, E-mail: fenggao2003@163.com [Faculty of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian, 116029 (China); Carbon Research Laboratory, Center for Nano Materials and Science, School of Chemical Engineering, State Key Lab of Fine Chemicals, Dalian University of Technology, Dalian, 116024 (China)

2016-06-25

Nitrogen-rich porous “green carbons” derived from abundant shrimp shell shows good performance for Li–S batteries. The strategy in this work is highlighted to selective removal of intrinsic CaCO{sub 3} in shrimp shell followed by KOH activation to tune the pore sizes of the obtained carbons. On the basis of the different porous structures, the discharge capacity of the obtained carbons as Li–S cathodes follows the order of micro-mesoporous carbon>mesoporous carbon>microporous carbon. The high capacity of the micro-mesoporous carbon is attributed to its positive characters such as the coexistence of micro-mesoporous structure, the large pore volume and the high specific surface area. Furthermore, well-dispersed nitrogen in the porous carbons is naturally doped and inherited from shrimp shell, and can help to enhance cycle stability when used as cathodes. As a result, all carbon cathodes exhibit the good cycle stability (>78%) due to their nitrogen doping induced chemical adsorption of sulfur on the surface areas of the porous carbons. Among them, mesoporous carbon cathode shows the best cycle stability with 90% retention within 100 cycles, which is mainly attributed to the synergistic effects of its both large pore size (5.12 nm) and high nitrogen content (6.67 wt %). - Highlights: • Nitrogen-rich porous “green carbons” derived from abundant shrimp shell shows good performance for Li–S batteries. • Intrinsic CaCO{sub 3} in shrimp shell as the natural template plays an important role on tailoring of the pore sizes of the porous carbons. • Nitrogen containing polysaccharide in shrimp shell benefits to produce nitrogen-rich carbons. • The effects of pore sizes on the electrochemical performance are investigated in detail. • The carbon-sulfur cathodes exhibit the good cycle stability because of nitrogen doping induced chemical adsorption of sulfur.

Nitrogen-doped porous “green carbon” derived from shrimp shell: Combined effects of pore sizes and nitrogen doping on the performance of lithium sulfur battery

International Nuclear Information System (INIS)

Qu, Jiangying; Lv, Siyuan; Peng, Xiyue; Tian, Shuo; Wang, Jia; Gao, Feng

2016-01-01

Nitrogen-rich porous “green carbons” derived from abundant shrimp shell shows good performance for Li–S batteries. The strategy in this work is highlighted to selective removal of intrinsic CaCO_3 in shrimp shell followed by KOH activation to tune the pore sizes of the obtained carbons. On the basis of the different porous structures, the discharge capacity of the obtained carbons as Li–S cathodes follows the order of micro-mesoporous carbon>mesoporous carbon>microporous carbon. The high capacity of the micro-mesoporous carbon is attributed to its positive characters such as the coexistence of micro-mesoporous structure, the large pore volume and the high specific surface area. Furthermore, well-dispersed nitrogen in the porous carbons is naturally doped and inherited from shrimp shell, and can help to enhance cycle stability when used as cathodes. As a result, all carbon cathodes exhibit the good cycle stability (>78%) due to their nitrogen doping induced chemical adsorption of sulfur on the surface areas of the porous carbons. Among them, mesoporous carbon cathode shows the best cycle stability with 90% retention within 100 cycles, which is mainly attributed to the synergistic effects of its both large pore size (5.12 nm) and high nitrogen content (6.67 wt %). - Highlights: • Nitrogen-rich porous “green carbons” derived from abundant shrimp shell shows good performance for Li–S batteries. • Intrinsic CaCO_3 in shrimp shell as the natural template plays an important role on tailoring of the pore sizes of the porous carbons. • Nitrogen containing polysaccharide in shrimp shell benefits to produce nitrogen-rich carbons. • The effects of pore sizes on the electrochemical performance are investigated in detail. • The carbon-sulfur cathodes exhibit the good cycle stability because of nitrogen doping induced chemical adsorption of sulfur.

Gas puff radiation performance as a function of radial mass distribution

International Nuclear Information System (INIS)

Coleman, Philip L.; Krishnan, Mahadevan; Prasad, Rahul; Qi, Niansheng; Waisman, Eduardo; Failor, B.H.; Levine, J.S.; Sze, H.

2002-01-01

The basic concept of a z-pinch, that JxB forces implode a shell of mass, creating a hot dense plasma on-axis, is coming under closer scrutiny. Wire arrays may start with an initial cold mass in a near 'ideal' shell, but in fact they appear to develop complex radial mass distributions well before the final x-ray output. We consider here the situation for gas puff z-pinches. While the ideal of a gas 'shell' has been the nominal objective for many years, detailed measurements of gas flow show that nozzles used for plasma radiation sources (PRS) also have complex radial distributions. In particular, there are significant data showing that the best x-ray yield comes from the least shell-like distributions. Recent experiments on the Double Eagle generator with argon have further enhanced this view. For those tests with a double 'shell' nozzle, there was a factor of almost 4 increase in yield when the relative mass (outer:inner) in the two shells was changed from 2:1 to less than 1:1. We suggest the following explanation. A configuration with most of its mass at large radii is subject to severe disruption by instabilities during the implosion. A more continuous radial mass distribution with dρ/dr < 0 may mitigate instability development (via the 'snowplow stabilization' mechanism) and thus enhance the thermalization of the kinetic energy of the imploding mass. In addition, the appropriate balance of outer to inner mass maximizes the formation of a strong shock in the core of the pinch that heats the plasma and leads to x-ray emission

INITIAL SINGLE-SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE

International Nuclear Information System (INIS)

JARAYSI, M.N.

2007-01-01

The ''Initial Single-Shell Tank System Performance Assessment for the Hanford Site [1] (SST PA) presents the analysis of the long-term impacts of residual wastes assumed to remain after retrieval of tank waste and closure of the SST farms at the US Department of Energy (DOE) Hanford Site. The SST PA supports key elements of the closure process agreed upon in 2004 by DOE, the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA). The SST PA element is defined in Appendix I of the ''Hanford Federal Facility Agreement and Consent Order'' (HFFACO) (Ecology et al. 1989) [2], the document that establishes the overall closure process for the SST and double-shell tank (DST) systems. The approach incorporated in the SST PA integrates substantive features of both hazardous and radioactive waste management regulations into a single analysis. The defense-in-depth approach used in this analysis defined two major engineering barriers (a surface barrier and the grouted tank structure) and one natural barrier (the vadose zone) that will be relied on to control waste release into the accessible environment and attain expected performance metrics. The analysis evaluates specific barrier characteristics and other site features that influence contaminant migration by the various pathways. A ''reference'' case and a suite of sensitivity/uncertainty cases are considered. The ''reference case'' evaluates environmental impacts assuming central tendency estimates of site conditions. ''Reference'' case analysis results show residual tank waste impacts on nearby groundwater, air resources; or inadvertent intruders to be well below most important performance objectives. Conversely, past releases to the soil, from previous tank farm operations, are shown to have groundwater impacts that re significantly above most performance objectives. Sensitivity/uncertainty cases examine single and multiple parameter variability along with plausible alternatives

Traces (ichnospecies Oichnus paraboloides of predatory gastropods on bivalve shells from the Seogwipo Formation, Jejudo, Korea

Directory of Open Access Journals (Sweden)

Dal-Yong Kong

2015-12-01

Full Text Available Circular to subcircular drill holes were identified on the bivalve shells collected from the Seogwipo Formation, Jejudo, Korea. A great majority of the drill holes (>70% were found on the surfaces of a bivalve species Glycymeris rotunda. They are characterized by a beveled sharp edge and paraboloid in cross section with larger outer borehole diameter (OBD; mean 4.21 mm and smaller inner borehole diameter (mean 2.94 mm. Walls of the drill holes are generally smooth, and walls ornamented with etched relief-like structures were also recognized. A slightly raised central boss observed in an incomplete specimen may indicate a failure of predator’s attack. All drill holes collected are classified as a single ichnospecies Oichnus paraboloides Bromley, 1981. They are interpreted as boring traces produced by predatory gastropods, particularly naticid gastropods. Most O. paraboloides boreholes are observed in the central area of shell surfaces; a few boreholes lie marginally, which may reflect a borehole-site selectivity. No correlation between size of prey (shell height and size of predator (OBD is recognized. It is likely, however, that drilled shells of about 30 mm in height represent optimal prey size for naticid predators that lived in a benthic Seogwipo community.

Self-optimizing Uplink Outer Loop Power Control for WCDMA Network

Directory of Open Access Journals (Sweden)

A. G. Markoc

2015-06-01

Full Text Available The increasing demands for high data rates, drives the efforts for more efficient usage of the finite natural radio spectrum resources. Existing wideband code division multiple access (WCDMA uplink outer loop power control has difficulty to answer to the new load on air interface. The main reason is that the maximum allowed noise rise per single user is fixed value. In worst case uplink load can be so high that all services, including conversational service, could be blocked. In this paper investigation has been performed to present correlation of main system parameters, used by uplink outer loop power control, to uplink load. Simulation has been created and executed to present difference in current implementation of uplink outer loop power control against proposed changes. Proposed solution is self-optimizing uplink outer loop power control in a way that maximum allowed noise rise per single user would be dynamically changed based on current uplink load on cell.

Core-Shell Processing of Natural Pigment: Upper Palaeolithic Red Ochre from Lovas, Hungary.

Directory of Open Access Journals (Sweden)

István E Sajó

Full Text Available Ochre is the common archaeological term for prehistoric pigments. It is applied to a range of uses, from ritual burials to cave art to medications. While a substantial number of Palaeolithic paint mining pits have been identified across Europe, the link between ochre use and provenance, and their antiquity, has never yet been identified. Here we characterise the mineralogical signature of core-shell processed ochre from the Palaeolithic paint mining pits near Lovas in Hungary, using a novel integration of petrographic and mineralogical techniques. We present the first evidence for core-shell processed, natural pigment that was prepared by prehistoric people from hematitic red ochre. This involved combining the darker red outer shell with the less intensely coloured core to efficiently produce an economical, yet still strongly coloured, paint. We demonstrate the antiquity of the site as having operated between 14-13 kcal BP, during the Epigravettian period. This is based on new radiocarbon dating of bone artefacts associated with the quarry site. The dating results indicate the site to be the oldest known evidence for core-shell pigment processing. We show that the ochre mined at Lovas was exported from the site based on its characteristic signature at other archaeological sites in the region. Our discovery not only provides a methodological framework for future characterisation of ochre pigments, but also provides the earliest known evidence for "value-adding" of products for trade.

Core-Shell Processing of Natural Pigment: Upper Palaeolithic Red Ochre from Lovas, Hungary.

Science.gov (United States)

Sajó, István E; Kovács, János; Fitzsimmons, Kathryn E; Jáger, Viktor; Lengyel, György; Viola, Bence; Talamo, Sahra; Hublin, Jean-Jacques

2015-01-01

Ochre is the common archaeological term for prehistoric pigments. It is applied to a range of uses, from ritual burials to cave art to medications. While a substantial number of Palaeolithic paint mining pits have been identified across Europe, the link between ochre use and provenance, and their antiquity, has never yet been identified. Here we characterise the mineralogical signature of core-shell processed ochre from the Palaeolithic paint mining pits near Lovas in Hungary, using a novel integration of petrographic and mineralogical techniques. We present the first evidence for core-shell processed, natural pigment that was prepared by prehistoric people from hematitic red ochre. This involved combining the darker red outer shell with the less intensely coloured core to efficiently produce an economical, yet still strongly coloured, paint. We demonstrate the antiquity of the site as having operated between 14-13 kcal BP, during the Epigravettian period. This is based on new radiocarbon dating of bone artefacts associated with the quarry site. The dating results indicate the site to be the oldest known evidence for core-shell pigment processing. We show that the ochre mined at Lovas was exported from the site based on its characteristic signature at other archaeological sites in the region. Our discovery not only provides a methodological framework for future characterisation of ochre pigments, but also provides the earliest known evidence for "value-adding" of products for trade.

Experiments with a Gas-Puff-On-Wire-Array Load on the GIT-12 Generator for Al K-shell Radiation Production at Microsecond Implosion Times

International Nuclear Information System (INIS)

Shishlov, Alexander V.; Baksht, Rina B.; Chaikovsky, Stanislav A.; Fedunin, Anatoly V.; Fursov, Fedor I.; Kovalchuk, Boris M.; Kokshenev, Vladimir A.; Kurmaev, Nikolai E.; Labetsky, Aleksey Yu.; Oreshkin, Vladimir I.; Rousskikh, Alexander G.; Lassalle, Francis; Bayol, Frederic

2006-01-01

Results of the experiments carried out on the GIT-12 generator at the current level of 3.5 MA and the Z-pinch implosion times from 700 ns to 1.1 μs are presented. A multi-shell (triple-shell) load configuration with the outer gas puffs (neon) and the inner wire array (aluminum) was used in the experiments. In the course of the research, implosion dynamics of the triple-shell z-pinch was studied, and the radiation yield in the spectral range of neon and aluminum K-lines have been measured. Optimization of the inner wire array parameters aimed at obtaining the maximum aluminum K-shell radiation yield has been carried out. As a result of optimization of the gas-puff-on-wire-array Z-pinch load, the aluminum K-shell radiation yield (hv> 1.55 keV) up to 4 kJ/cm in the radiation pulse with FWHM less than 30 ns has been obtained. Comparison of the experimental results with the results of preliminary 1D RMHD simulations allows a conclusion that at least 2/3 of the generator current is switched from a gas puff to an aluminum wire array. The radiation yield in the spectral range of neon K-lines (0.92-1.55 keV) increases considerably in the shots with the inner wire array in comparison with the shots carried out with the outer gas puffs only. The radiation yield in the spectral range above 1 keV registered in the experiments reached 10 kJ/cm. The presence of a high portion of the neon plasma inside an inner wire array can limit the radiation yield in the spectral range above 1.55 keV

Saturn's outer magnetosphere

Science.gov (United States)

Schardt, A. W.; Behannon, K. W.; Carbary, J. F.; Eviatar, A.; Lepping, R. P.; Siscoe, G. L.

1983-01-01

Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like Earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

Outer crust of nonaccreting cold neutron stars

International Nuclear Information System (INIS)

Ruester, Stefan B.; Hempel, Matthias; Schaffner-Bielich, Juergen

2006-01-01

The properties of the outer crust of nonaccreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables, updating in particular the classic work of Baym, Pethick, and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 are used and a thorough comparison of many modern theoretical nuclear models, both relativistic and nonrelativistic, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared to check their differences concerning the neutron drip line, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the drip line in the outer crust of nonaccreting cold neutron stars

Template-free synthesis of ordered ZnO@ZnS core-shell arrays for high performance supercapacitors.

Science.gov (United States)

Yan, Hailong; Li, Tong; Lu, Yang; Cheng, Jinbing; Peng, Tao; Xu, Jinyou; Yang, Linying; Hua, Xiangqiang; Liu, Yunxin; Luo, Yongsong

2016-11-28

In this article, ordered ZnO@ZnS core-shell structures have been produced on a stainless mesh by a two-step approach without using a template. ZnO nanorods fabricated by a chemical vapor method are transferred into a 50 ml autoclave for a second stage ion-exchange reaction followed by heating at 120 °C for 4-16 h. The ZnO core is prepared as the conducting channel and ZnS as the active material. Such unique architecture exhibits remarkable electrochemical performance with high capacitance and desirable cycle life. When evaluating as the electrode for supercapacitors, the ZnO@ZnS core-shell structure delivers a high specific capacitance of 603.8 F g -1 at a current density of 2 A g -1 , with 9.4% capacitance loss after cycling 3000 times. The fabrication strategy presented here is simple and cost-effective, which can open new avenues for large-scale applications of the novel materials in energy storage.

Shell model studies in the N = 54 isotones 99Rh, 100Pd

International Nuclear Information System (INIS)

Ghugre, S.S.; Sarkar, S.; Chintalapudi, S.N.

1996-01-01

The shell model in reproducing the observed level is used to investigate the observed level sequences in 99 Rh and 100 Pd within the spherical shell model framework. Shell model calculations have been performed using the code OXBASH

Design criteria of launching rockets for burst aerial shells

Energy Technology Data Exchange (ETDEWEB)

Kuwahara, T.; Takishita, Y.; Onda, T.; Shibamoto, H.; Hosaya, F. [Hosaya Kako Co. Ltd (Japan); Kubota, N. [Mitsubishi Electric Corporation (Japan)

2000-04-01

Rocket motors attached to large-sized aerial shells are proposed to compensate for the increase in the lifting charge in the mortar and the thickness of the shell wall. The proposal is the result of an evaluation of the performance of solid propellants to provide information useful in designing launch rockets for large-size shells. The propellants composed of ammonium perchlorate and hydroxy-terminated polybutadiene were used to evaluate the ballistic characteristics such as the relationship between propellant mass and trajectories of shells and launch rockets. In order to obtain an optimum rocket design, the evaluation also included a study of the velocity and height of the rocket motor and shell separation. A launch rocket with a large-sized shell (84.5 cm in diameter) was designed to verify the effectiveness of this class of launch system. 2 refs., 6 figs.

Improvement of permanent magnet machines performance by including magnetic shells into the rotor geometry

International Nuclear Information System (INIS)

Alnaemi, F.; Moses, A.J.

2003-01-01

FEM modelling of PM motor was carried out to demonstrate the effects of the addition of various types of ferromagnetic tubes (shell) to a rotor of surface mount permanent magnet motor. An enhancement in magnet operating point towards the high field region is obtained. A shell made of amorphous ribbon offers optimum advantages

Amorphous TiO2 Shells: A Vital Elastic Buffering Layer on Silicon Nanoparticles for High-Performance and Safe Lithium Storage.

Science.gov (United States)

Yang, Jianping; Wang, Yunxiao; Li, Wei; Wang, Lianjun; Fan, Yuchi; Jiang, Wan; Luo, Wei; Wang, Yang; Kong, Biao; Selomulya, Cordelia; Liu, Hua Kun; Dou, Shi Xue; Zhao, Dongyuan

2017-12-01

Smart surface coatings of silicon (Si) nanoparticles are shown to be good examples for dramatically improving the cyclability of lithium-ion batteries. Most coating materials, however, face significant challenges, including a low initial Coulombic efficiency, tedious processing, and safety assessment. In this study, a facile sol-gel strategy is demonstrated to synthesize commercial Si nanoparticles encapsulated by amorphous titanium oxide (TiO 2 ), with core-shell structures, which show greatly superior electrochemical performance and high-safety lithium storage. The amorphous TiO 2 shell (≈3 nm) shows elastic behavior during lithium discharging and charging processes, maintaining high structural integrity. Interestingly, it is found that the amorphous TiO 2 shells offer superior buffering properties compared to crystalline TiO 2 layers for unprecedented cycling stability. Moreover, accelerating rate calorimetry testing reveals that the TiO 2 -encapsulated Si nanoparticles are safer than conventional carbon-coated Si-based anodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Outer Synchronization of Complex Networks by Impulse

International Nuclear Information System (INIS)

Sun Wen; Yan Zizong; Chen Shihua; Lü Jinhu

2011-01-01

This paper investigates outer synchronization of complex networks, especially, outer complete synchronization and outer anti-synchronization between the driving network and the response network. Employing the impulsive control method which is uncontinuous, simple, efficient, low-cost and easy to implement in practical applications, we obtain some sufficient conditions of outer complete synchronization and outer anti-synchronization between two complex networks. Numerical simulations demonstrate the effectiveness of the proposed impulsive control scheme. (general)

Rapid determination of parabens in seafood sauces by high-performance liquid chromatography: A practical comparison of core-shell particles and sub-2 μm fully porous particles.

Science.gov (United States)

Ye, Jing; Cao, Xiaoji; Cheng, Zhuo; Qin, Ye; Lu, Yanbin

2015-12-01

In this work, the chromatographic performance of superficially porous particles (Halo core-shell C18 column, 50 mm × 2.1 mm, 2.7 μm) was compared with that of sub-2 μm fully porous particles (Acquity BEH C18 , 50 mm × 2.1 mm, 1.7 μm). Four parabens, methylparaben, ethylparaben, propylparaben, and butylparaben, were used as representative compounds for calculating the plate heights in a wide flow rate range and analyzed on the basis of the Van Deemter and Knox equations. Theoretical Poppe plots were constructed for each column to compare their kinetic performance. Both phases gave similar minimum plate heights when using nonreduced coordinates. Meanwhile, the flat C-term of the core-shell column provided the possibilities for applying high flow rates without significant loss in efficiency. The low backpressure of core-shell particles allowed this kind of column, especially compatible with conventional high-performance liquid chromatography systems. Based on these factors, a simple high-performance liquid chromatography method was established and validated for the determination of parabens in various seafood sauces using the Halo core-shell C18 column for separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radar attenuation in Europa's ice shell: obstacles and opportunities for constraining shell thickness and thermal structure

Science.gov (United States)

Kalousova, Klara; Schroeder, Dustin M.; Soderlund, Krista M.; Sotin, Christophe

2016-10-01

With its strikingly young surface and possibly recent endogenic activity, Europa is one of the most exciting bodies within our Solar System and a primary target for spacecraft exploration. Future missions to Europa are expected to carry ice penetrating radar instruments which are powerful tools to investigate the subsurface thermophysical structure of its ice shell.Several authors have addressed the 'penetration depth' of radar sounders at icy moons, however, the concept and calculation of a single value penetration depth is a potentially misleading simplification since it ignores the thermal and attenuation structure complexity of a realistic ice shell. Here we move beyond the concept of a single penetration depth by exploring the variation in two-way radar attenuation for a variety of potential thermal structures of Europa's ice shell as well as for a low loss and high loss temperature-dependent attenuation model. The possibility to detect brines is also investigated.Our results indicate that: (i) for all ice shell thicknesses investigated (5-30 km), a nominal satellite-borne radar sounder will penetrate between 15% and 100% of the total thickness, (ii) the maximum penetration depth strongly varies laterally with the deepest penetration possible through the cold downwellings, (iii) the direct detection of the ice/ocean interface might be possible for shells of up to 15 km if the radar signal travels through the cold downwelling, (iv) even if the ice/ocean interface is not detected, the penetration through most of the shell could constrain the deep shell structure through the loss of signal, and (v) for all plausible ice shells the two-way attenuation to the eutectic point is ≤30 dB which shows a robust potential for longitudinal investigation of the ice shell's shallow structure.Part of this work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. K.K. acknowledges support by the Grant Agency of the

Free vibration analysis of delaminated composite shells using different shell theories

International Nuclear Information System (INIS)

Nanda, Namita; Sahu, S.K.

2012-01-01

Free vibration response of laminated composite shells with delamination is presented using the finite element method based on first order shear deformation theory. The shell theory used is the extension of dynamic, shear deformable theory according to the Sanders' first approximation for doubly curved shells, which can be reduced to Love's and Donnell's theories by means of tracers. An eight-noded C 0 continuity, isoparametric quadrilateral element with five degrees of freedom per node is used in the formulation. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code. The natural frequencies of the delaminated cylindrical (CYL), spherical (SPH) and hyperbolic paraboloid (HYP) shells are determined by using the above mentioned shell theories, namely Sanders', Love's, and Donnell's. The validity of the present approach is established by comparing the authors' results with those available in the literature. Additional studies on free vibration response of CYL, SPH and HYP shells are conducted to assess the effects of delamination size and number of layers considering all three shell theories. It is shown that shell theories according to Sanders and Love always predict practically identical frequencies. Donnell's theory gives reliable results only for shallow shells. Moreover, the natural frequency is found to be very sensitive to delamination size and number of layers in the shell.

Fluxgate magnetometers for outer planets exploration

Science.gov (United States)

Acuna, M. H.

1974-01-01

The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.

Multidimensional Analysis of Direct-Drive Plastic-Shell Implosions on OMEGA

Science.gov (United States)

Radha, P. B.

2004-11-01

Direct-drive implosions of plastic shells with the OMEGA laser are used as energy-scaled warm surrogates for ignition cryogenic targets designed for use on the National Ignition Facility. Plastic targets involve varying shell thickness (15 to 33 μm), fill pressures (3 to 15 atm), and shell adiabats. The multidimensional hydrodynamics code DRACO is used to evaluate the effects of capsule-surface roughness and illumination nonuniformities on target performance. These simulations indicate that shell stability during the acceleration phase plays a critical role in determining fusion yields. For shells that are thick enough to survive the Rayleigh--Taylor growth, target yields are significantly reduced by growth of the long (ℓ surrogacy between these plastic-shell implosions and the cryogenic ignition designs.

Cycling and floating performance of symmetric supercapacitor derived from coconut shell biomass

Science.gov (United States)

Barzegar, Farshad; Khaleed, Abubakar A.; Ugbo, Faith U.; Oyeniran, Kabir O.; Momodu, Damilola Y.; Bello, Abdulhakeem; Dangbegnon, Julien K.; Manyala, Ncholu

2016-11-01

This work present two-step synthesizes route to low-cost mesoporous carbon from coconut shell. The electrochemical characterization of the coconut shell based activated carbon (CSAC) material as electrode for supercapacitor showed a specific capacitance of 186 F g-1, energy density of ˜11 Wh kg-1 and power density of 325 W kg-1 at a 0.5 A g-1 with an excellent stability after floating for 100 h and cycling for 10000 cycles in polymer gel electrolyte. The CSAC showed very good potential as a stable material for supercapacitors desirable for high power applications.

Cycling and floating performance of symmetric supercapacitor derived from coconut shell biomass

Directory of Open Access Journals (Sweden)

Farshad Barzegar

2016-11-01

Full Text Available This work present two-step synthesizes route to low-cost mesoporous carbon from coconut shell. The electrochemical characterization of the coconut shell based activated carbon (CSAC material as electrode for supercapacitor showed a specific capacitance of 186 F g-1, energy density of ∼11 Wh kg-1 and power density of 325 W kg-1 at a 0.5 A g-1 with an excellent stability after floating for 100 h and cycling for 10000 cycles in polymer gel electrolyte. The CSAC showed very good potential as a stable material for supercapacitors desirable for high power applications.

Effective enhancement of gas separation performance in mixed matrix membranes using core/shell structured multi-walled carbon nanotube/graphene oxide nanoribbons

Science.gov (United States)

Xue, Qingzhong; Pan, Xinglong; Li, Xiaofang; Zhang, Jianqiang; Guo, Qikai

2017-02-01

Novel core/shell structured multi-walled carbon nanotube/graphene oxide nanoribbons (MWCNT@GONRs) nanohybrids were successfully prepared using a modified chemical longitudinal unzipping method. Subsequently, the MWCNT@GONRs nanohybrids were used as fillers to enhance the gas separation performance of polyimide based mixed matrix membranes (MMMs). It is found that MMMs concurrently exhibited higher gas selectivity and higher gas permeability compared to pristine polyimide. The high gas selectivity could be attributed to the GONRs shell, which provided a selective barrier and large gas adsorbed area, while the high gas permeability resulted from the hollow structured MWCNTs core with smooth internal surface, which acted as a rapid transport channel. MWCNT@GONRs could be promising candidates to improve gas separation performance of MMMs due to the unique microstructures, ease of synthesis and low filling loading.

LO2/LH2 propulsion for outer planet orbiter spacecraft

Science.gov (United States)

Garrison, P. W.; Sigurdson, K. B.

1983-01-01

Galileo class orbiter missions (750-1500 kg) to the outer planets require a large postinjection delta-V for improved propulsion performance. The present investigation shows that a pump-fed low thrust LO2/LH2 propulsion system can provide a significantly larger net on-orbit mass for a given delta-V than a state-of-the-art earth storable, N2O4/monomethylhydrazine pressure-fed propulsion system. A description is given of a conceptual design for a LO2/LH2 pump-fed propulsion system developed for a Galileo class mission to the outer planets. Attention is given to spacecraft configuration, details regarding the propulsion system, the thermal control of the cryogenic propellants, and aspects of mission performance.

Co{sub 3}O{sub 4} nanowires@MnO{sub 2} nanolayer or nanoflakes core–shell arrays for high-performance supercapacitors: The influence of morphology on performance

Energy Technology Data Exchange (ETDEWEB)

Wang, Ke [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Shi, Zhongqi, E-mail: zhongqishi@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Yuanyuan [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Ye, Zhiguo [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Xia, Hongyan [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Liu, Guiwu [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Qiao, Guanjun, E-mail: gjqiao@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

2015-03-05

Highlights: • MnO{sub 2} nanolayer is coated on Co{sub 3}O{sub 4} nanowire arrays forming a core–shell nanocable structure via chemical bath deposition. • The electrochemical performances of the MnO{sub 2} with two different morphologies are compared and investigated. • Both the Co{sub 3}O{sub 4} nanowires@MnO{sub 2} nanolayer and nanoflakes core–shell arrays possess high specific capacitance. - Abstract: The Co{sub 3}O{sub 4} nanowires@MnO{sub 2} nanolayer or nanoflakes core–shell arrays (Co{sub 3}O{sub 4}@MnO{sub 2} nanolayer or nanoflakes NWAs) supported on carbon fiber paper have been fabricated via a facile and green method and further investigated on the performance as the electrodes for supercapacitors. Our experimental results evidently indicate that both the Co{sub 3}O{sub 4}@MnO{sub 2} nanoflakes and nanolayer NWAs are capable of delivering specific capacitances as high as 1209.4 and 1215.6 F g{sup −1} (based on the MnO{sub 2}) at the current density of 1 A g{sup −1}. Due to the delicately designed hierarchical nanostructure that distributing the nanoscaled MnO{sub 2} on the nanowires with better electric conductivity, the active materials take advantage of the high effective surface area, facile electrolyte diffusion and fast electron transfer. The phenomenon that the Co{sub 3}O{sub 4}@MnO{sub 2} nanolayer NWAs with smaller specific surface area become superior in electrochemical performance to the Co{sub 3}O{sub 4}@MnO{sub 2} nanoflakes NWAs has been carefully investigated. The smaller charge transfer and electrolyte diffusion resistances are mainly demonstrated to be responsible. The analyses presented here could contribute to developing the optimal nanostructure of electrode materials for high-performance supercapacitors.

Charge symmetry of the nuclear force as off-shell constraint

International Nuclear Information System (INIS)

Sauer, P.U.

1975-01-01

Off-shell changes are generated in the 1 S 0 nucleon-nucleon interaction using the Reid soft-core potential and unitary transformations of short range. Charge symmetry is assumed for the nuclear force. The same off-shell variations of the Reid potential are employed as the hadronic part of the proton-proton interaction and as neutron-neutron interaction. The Reid potential fits the experimental proton-proton data. It also accounts for the neutron-neutron scattering length with satisfying accuracy. The off-shell behavior of the Reid potential is varied in two different ways. First, off-shell changes consistent with the experimental proton-proton data can be selected. (auth) are performed which preserve the fit to the proton-proton data. Most transformed potentials of the type attempted here are unable to yield the correct experimental value of the neutron-neutron scattering length and have to be rejected. A simple practical rule is given according to which the off-shell changes consistent with the neutron-neutron scattering length can be selected. Second, off-shell changes are performed which leave the neutron-neutron scattering length unaltered. Transformed potentials of this type have usually been employed in nuclear-structure calculations. The potentials which exhibit large off-shell effects in nuclear structure are unable to account for the experimental proton-proton data. Their off-shell effects are therefore of no physical significance, and the potentials have to be rejected. A simple practical rule is given according to which the off-shell changes consistent with the experimental proton-proton data can be selected. (U.S.)

Shell model description of Ge isotopes

International Nuclear Information System (INIS)

Hirsch, J G; Srivastava, P C

2012-01-01

A shell model study of the low energy region of the spectra in Ge isotopes for 38 ≤ N ≤ 50 is presented, analyzing the excitation energies, quadrupole moments, B(E2) values and occupation numbers. The theoretical results have been compared with the available experimental data. The shell model calculations have been performed employing three different effective interactions and valence spaces. We have used two effective shell model interactions, JUN45 and jj44b, for the valence space f 5/2 pg 9/2 without truncation. To include the proton subshell f 7/2 in valence space we have employed the fpg effective interaction due to Sorlin et al., with 48 Ca as a core and a truncation in the number of excited particles.

The examination of the effects of the flow baffle on the thermal hydraulic performance of IHX shell side

International Nuclear Information System (INIS)

Kim, W. K.; Sim, Y. S.; Kim, S. O.; Baek, B. J.

2002-01-01

The effects of the flow baffle on the thermal hydraulic performance of IHX shell side has been examined using ASTEEPL, 2DHX code for the variation of baffle distance, baffle cut and baffle flow hole design data. When KALIMER design data were selected as a base for the study, a shell baffle structures does not influence on a total heat transfer rate and it is better to reduce baffle distance rather than baffle flow hole size from the view of pressure loss in the IHX. Radial thermal imbalance between tubes was reduced to 6 .deg. C when the number of baffle is beyond 13. And thermal imbalance decreased also when flow hole size decreases. If flow hole clogs perfectly, thermal imbalance can be reduced up to 2 .deg. C

Minute co-variations of Sr/Ca ratios and microstructures in the aragonitic shell of Cerastoderma edule (Bivalvia) - Are geochemical variations at the ultra-scale masking potential environmental signals?

Science.gov (United States)

Füllenbach, Christoph S.; Schöne, Bernd R.; Shirai, Kotaro; Takahata, Naoto; Ishida, Akizumi; Sano, Yuji

2017-05-01

It remains a challenging task to reconstruct water temperatures from Sr/Ca ratios of bivalve shells. Although in many aragonitic species, Sr/Ca is negatively correlated to temperature - which is expected based on abiogenic precipitation experiments, the incorporation of Sr into the shell of bivalves is strongly controlled by physiological processes and occurs away from the predicted thermodynamic equilibrium. Strontium-to-calcium ratios of aragonitic shells remain far below that of the ambient water. Moreover, Sr concentrations vary considerably among shell portions consisting of different microstructures and/or organic content. Values observed at annual growth lines and within the intervening shell portions (= annual growth increments) deviate much stronger from each other than expected from a change in temperature or Sr/Cawater. As demonstrated here by ultra-high-resolution chemical analysis (EPMA, NanoSIMS) of a Cerastoderma edule shell, Sr concentrations are also heterogeneously distributed at approximately micrometer resolution. For example, in the outer portion of the outer shell layer, Sr/Ca ratios were statistically significantly (t-, u-tests) higher at circatidal growth lines (irregular simple prismatic structure; arithmetic mean ± 1 standard deviation = 2.86 ± 0.38 mmol/mol; n = 53) than within circatidal increments (nondenticular prismatic structure; 2.42 ± 0.25 mmol/mol; n = 51). S/Cashell, a representative of the concentration of organics, showed the opposite pattern, i.e., significantly higher values in circatidal increments (2.37 ± 0.29 mmol/mol; n = 51) than at circatidal growth lines (2.13 ± 0.47 mmol/mol; n = 53). Overall highest values of Sr/Cashell (3.47 ± 0.65 mmol/mol; n = 3) and S/Cashell (3.98 ± 0.65 mmol/mol; n = 3), however, were typically associated with annual growth lines and larger biomineral units. The intimate link between Sr/Cashell, S/Cashell and shell architecture may indicate that microstructures or the processes

Slush Fund: The Multiphase Nature of Oceanic Ices and Its Role in Shaping Europa's Icy Shell

Science.gov (United States)

Buffo, J.; Schmidt, B. E.; Huber, C.

2017-12-01

The role of Europa's ice shell in mediating ocean-surface interaction, constraining potential habitability of the underlying hydrosphere, and dictating the surface morphology of the moon is discussed extensively in the literature, yet the dynamics and characteristics of the shell itself remain largely unconstrained. Some of the largest unknowns arise from underrepresented physics and varying a priori assumptions built into the current ice shell models. Here we modify and apply a validated one-dimensional reactive transport model designed to simulate the formation and evolution of terrestrial sea ice to the Europa environment. The top-down freezing of sea ice due to conductive heat loss to the atmosphere is akin to the formation of the Jovian moon's outer ice shell, albeit on a different temporal and spatial scale. Nevertheless, the microscale physics that govern the formation of sea ice on Earth (heterogenous solidification leading to brine pockets and channels, multiphase reactive transport phenomena, gravity drainage) likely operate in a similar manner at the ice-ocean interface of Europa, dictating the thermal, chemical, and mechanical properties of the ice shell. Simulations of the European ice-ocean interface at different stages during the ice shell's evolution are interpolated to produce vertical profiles of temperature, salinity, solid fraction, and eutectic points throughout the entire shell. Additionally, the model is coupled to the equilibrium chemistry package FREZCHEM to investigate the impact a diverse range of putative European ocean chemistries has on ice shell properties. This method removes the need for a priori assumptions of impurity entrainment rates and ice shell properties, thus providing a first principles constraint on the stratigraphic characteristics of a simulated European ice shell. These insights have the potential to improve existing estimates for the onset of solid state convection, melt lens formation due to eutectic melting, ice

Germanium Nanowires-in-Graphite Tubes via Self-Catalyzed Synergetic Confined Growth and Shell-Splitting Enhanced Li-Storage Performance.

Science.gov (United States)

Sun, Yong; Jin, Shuaixing; Yang, Guowei; Wang, Jing; Wang, Chengxin

2015-04-28

Despite the high theoretical capacity, pure Ge has various difficulties such as significant volume expansion and electron and Li(+) transfer problems, when applied as anode materials in lithium ion battery (LIB), for which the solution would finally rely on rational design like advanced structures and available hybrid. Here in this work, we report a one-step synthesis of Ge nanowires-in-graphite tubes (GNIGTs) with the liquid Ge/C synergetic confined growth method. The structure exhibits impressing LIB behavior in terms of both cyclic stability and rate performance. We found the semiclosed graphite shell with thickness of ∼50 layers experience an interesting splitting process that was driven by electrolyte diffusion, which occurs before the Ge-Li alloying plateau begins. Two types of different splitting mechanism addressed as "inside-out"/zipper effect and "outside-in" dominate this process, which are resulted from the SEI layer growing longitudinally along the Ge-graphite interface and the lateral diffusion of Li(+) across the shell, respectively. The former mechanism is the predominant way driving the initial shell to split, which behaves like a zipper with SEI layer as invisible puller. After repeated Li(+) insertion/exaction, the GNIGTs configuration is finally reconstructed by forming Ge nanowires-thin graphite strip hybrid, both of which are in close contact, resulting in enormous enchantment to the electrons/Li(+) transport. These features make the structures perform well as anode material in LIB. We believe both the progress in 1D assembly and the structure evolution of this Ge-C composite would contribute to the design of advanced LIB anode materials.

Artificially evolved functional shell morphology of burrowing bivalves

DEFF Research Database (Denmark)

Germann, D. P.; Schatz, W.; Hotz, Peter Eggenberger

2014-01-01

dimensional (3D) objects, the first ever artificial evolution of a physical bivalve shell was performed. The result was a vertically flattened shell occupying only the top sediment layers. Insufficient control of the sediment was the major limitation of the setup and restricted the significance of the results......, there are almost no studies experimentally testing their dynamic properties. To investigate the functional morphology of the bivalve shell, we employed a synthetic methodology and built an experimental setup to simulate the burrowing process. Using an evolutionary algorithm and a printer that prints three...

High performance and durability of order-structured cathode catalyst layer based on TiO_2@PANI core-shell nanowire arrays

International Nuclear Information System (INIS)

Chen, Ming; Wang, Meng; Yang, Zhaoyi; Wang, Xindong

2017-01-01

Highlights: • TiO_2@PANI core-shell nanowire arrays were prepared and applied as catalyst support. • As-prepared Pt-TiO_2@PANI core-shell nanowire arrays were applied as order-structured cathode catalyst layer. • The novel cathode catalyst structure without Nafion"® ionomer enhance the performance and durability of PEMFC. - Abstract: In this paper, an order-structured cathode catalyst layer consisting of Pt-TiO_2@PANI core-shell nanowire arrays that in situ grown on commercial gas diffusion layer (GDL) are prepared and applied to membrane electrode assembly (MEA) of proton exchange membrane fuel cell (PEMFC). In order to prepare the TiO_2@PANI core-shell nanowire arrays with suitable porosity and prominent conductivity, the morphologies of the TiO_2 nanoarray and electrochemical polymerization process of aniline are schematically investigated. The MEA with order-structured cathode catalyst layer is assembled in the single cell to evaluate the electrochemical performance and durability of PEMFC. As a result, the PEMFC with order-structured cathode catalyst layer shows higher peak power density (773.54 mW cm"−"2) than conventional PEMFC (699.30 mW cm"−"2). Electrochemically active surface area (ECSA) and charge transfer impedance (R_c_t) are measured before and after accelerated degradation test (ADT), and the corresponding experimental results indicate the novel cathode structure exhibits a better stability with respect to conventional cathode. The enhanced electrochemical performance and durability toward PEMFC can be ascribed to the order-structured cathode nanoarray structure with high specific surface area increases the utilization of catalyst and reduces the tortuosity of transport pathways, and the synergistic effect between TiO_2@PANI support and Pt nanoparticles promotes the high efficiency of electrochemical reaction and improves the stability of catalyst. This research provides a facile and controllable method to prepare order

Composted oyster shell as lime fertilizer is more effective than fresh oyster shell.

Science.gov (United States)

Lee, Young Han; Islam, Shah Md Asraful; Hong, Sun Joo; Cho, Kye Man; Math, Renukaradhya K; Heo, Jae Young; Kim, Hoon; Yun, Han Dae

2010-01-01

Physio-chemical changes in oyster shell were examined, and fresh and composted oyster shell meals were compared as lime fertilizers in soybean cultivation. Structural changes in oyster shell were observed by AFM and FE-SEM. We found that grains of the oyster shell surface became smoother and smaller over time. FT-IR analysis indicated the degradation of a chitin-like compound of oyster shell. In chemical analysis, pH (12.3+/-0.24), electrical conductivity (4.1+/-0.24 dS m(-1)), and alkaline powder (53.3+/-1.12%) were highest in commercial lime. Besides, pH was higher in composted oyster shell meal (9.9+/-0.53) than in fresh oyster shell meal (8.4+/-0.32). The highest organic matter (1.1+/-0.08%), NaCl (0.54+/-0.03%), and moisture (15.1+/-1.95%) contents were found in fresh oyster shell meal. A significant higher yield of soybean (1.33 t ha(-1)) was obtained by applying composted oyster shell meal (a 21% higher yield than with fresh oyster shell meal). Thus composting of oyster shell increases the utility of oyster shell as a liming material for crop cultivation.

Subshell resolved L shell ionization of Bi and U induced by 16 - 45 keV electrons

International Nuclear Information System (INIS)

Rahangdale, Hitesh; Das, Pradipta K.; Saha, S.; Mitra, D.

2015-01-01

Electron induced inner-shell ionization is important for both fundamental and applied research. Ionization of outer atomic energy levels has been studied extensively than for inner levels. Knowledge of inner shell ionization cross sections is important in X-ray and Auger electron spectroscopy and in the fields of astrophysics, plasma physics, surface science and many more. At electron impact energies near the atomic binding energies the distortion of the wave functions from plane wave towards a spherical wave, due to the electrostatic field of the atoms, needs to be considered. The distorted wave Born approximation (DWBA) calculations, taking relativistic effects and exchange interaction into account, is used to estimate the K, L and M-shell ionization cross-section for the atoms. Earlier experiments on electron impact ionization studies focused mainly on K-shell ionization cross-section, while L and M-shell ionization data were hardly reported. A review of the existing L-shell ionization cross-section data shows that, while the X-ray production cross-sections by electron impact were reported quite a few times, the reporting of subshell resolved ionization cross-sections were rarely found near the ionization threshold region. In the present work, we have measured the X ray production cross-sections of different L lines of Bi and U induced by 16-45 keV electrons and converted the obtained values to the subshell specific ionization cross-sections. The experimental data are compared with the theoretical calculations based on the (DWBA) obtained from PENELOPE. To the best of our knowledge, the subshell resolved electron induced ionization cross-sections for the L-shell of Bi and U are reported here for the first time at the energy values near the corresponding ionization threshold. (author)

On the core-mass-shell-luminosity relation for shell-burning stars

International Nuclear Information System (INIS)

Jeffery, C.S.; Saint Andrews Univ.

1988-01-01

Core-mass-shell-luminosity relations for several types of shell-burning star have been calculated using simultaneous differential equations derived from simple homology approximations. The principal objective of obtaining a mass-luminosity relation for helium giants was achieved. This relation gives substantially higher luminosities than the equivalent relation for H-shell stars with core masses greater than 1 solar mass. The algorithm for calculating mass-luminosity relations in this fashion was investigated in detail. Most of the assumptions regarding the physics in the shell do not play a critical role in determining the core-mass-shell-luminosity relation. The behaviour of the core-mass-core-radius relation for a growing degenerate core as a single unique function of mass and growth rate needs to be defined before a single core-mass-shell-luminosity relation for all H-shell stars can be obtained directly from the homology approximations. (author)

Outer Continental Shelf Lands Act

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data represents geographic terms used within the Outer Continental Shelf Lands Act (OCSLA or Act). The Act defines the United States outer continental shelf...

Synthesis of Hβ (core)/SAPO-11 (shell) Composite Molecular Sieve and its Catalytic Performances in the Methylation of Naphthalene with Methanol

International Nuclear Information System (INIS)

Wang, Xiaoxiao; Zhao, Liangfu; Guo, Shaoqing

2013-01-01

Hβ (core)/SAPO-11 (shell) composite molecular sieve was synthesized by the hydrothermal method in order to combine the advantages of Hβ and SAPO-11 for the methylation of naphthalene with methanol. For comparison, the mechanical mixture was prepared through the blending of Hβ and SAPO-11. The physicochemical properties of Hβ, SAPO-11, the composite and the mechanical mixture were characterized by various characterization methods. The characterization results indicated that Hβ/SAPO-11 composite molecular sieve exhibited a core-shell structure, with the Hβ phase as the core and the SAPO-11 phase as the shell. The pore diameter of the composite was between that of Hβ and SAPO-11. The composite had fewer acid sites than Hβ and mechanical mixture while more acid sites than SAPO-11. The experimental results indicated that the composite exhibited high catalytic performances for the methylation of naphthalene with methanol

Variation in Orthologous Shell-Forming Proteins Contribute to Molluscan Shell Diversity.

Science.gov (United States)

Jackson, Daniel J; Reim, Laurin; Randow, Clemens; Cerveau, Nicolas; Degnan, Bernard M; Fleck, Claudia

2017-11-01

Despite the evolutionary success and ancient heritage of the molluscan shell, little is known about the molecular details of its formation, evolutionary origins, or the interactions between the material properties of the shell and its organic constituents. In contrast to this dearth of information, a growing collection of molluscan shell-forming proteomes and transcriptomes suggest they are comprised of both deeply conserved, and lineage specific elements. Analyses of these sequence data sets have suggested that mechanisms such as exon shuffling, gene co-option, and gene family expansion facilitated the rapid evolution of shell-forming proteomes and supported the diversification of this phylum specific structure. In order to further investigate and test these ideas we have examined the molecular features and spatial expression patterns of two shell-forming genes (Lustrin and ML1A2) and coupled these observations with materials properties measurements of shells from a group of closely related gastropods (abalone). We find that the prominent "GS" domain of Lustrin, a domain believed to confer elastomeric properties to the shell, varies significantly in length between the species we investigated. Furthermore, the spatial expression patterns of Lustrin and ML1A2 also vary significantly between species, suggesting that both protein architecture, and the regulation of spatial gene expression patterns, are important drivers of molluscan shell evolution. Variation in these molecular features might relate to certain materials properties of the shells of these species. These insights reveal an important and underappreciated source of variation within shell-forming proteomes that must contribute to the diversity of molluscan shell phenotypes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Testing refined shell-model interactions in the sd shell: Coulomb excitation of Na26

CERN Document Server

Siebeck, B; Blazhev, A; Reiter, P; Altenkirch, R; Bauer, C; Butler, P A; De Witte, H; Elseviers, J; Gaffney, L P; Hess, H; Huyse, M; Kröll, T; Lutter, R; Pakarinen, J; Pietralla, N; Radeck, F; Scheck, M; Schneiders, D; Sotty, C; Van Duppen, P; Vermeulen, M; Voulot, D; Warr, N; Wenander, F

2015-01-01

Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal sd interaction (USD) describing nuclei within the sd shell yielded two new interactions—USDA and USDB—causing changes in the theoretical description of these nuclei. Purpose: Transition matrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus Na26 with 7 valence neutrons and 3 valence protons outside the doubly-magic 16O core is used as a test case. Method: A radioactive beam experiment with Na26 (T1/2=1,07s) was performed at the REX-ISOLDE facility (CERN) using Coulomb excitation at safe energies below the Coulomb barrier. Scattered particles were detected with an annular Si detector in coincidence with γ rays observed by the segmented MINIBALL array. Coulomb excitation cross sections...

Deformation Behavior of Press Formed Shell by Indentation and Its Numerical Simulation

Directory of Open Access Journals (Sweden)

Minoru Yamashita

2015-01-01

Full Text Available Deformation behavior and energy absorbing performance of the press formed aluminum alloy A5052 shells were investigated to obtain the basic information regarding the mutual effect of the shell shape and the indentor. Flat top and hemispherical shells were indented by the flat- or hemispherical-headed indentor. Indentation force in the rising stage was sharper for both shell shapes when the flat indentor was used. Remarkable force increase due to high in-plane compressive stress arisen by the appropriate tool constraint was observed in the early indentation stage, where the hemispherical shell was deformed with the flat-headed indentor. This aspect is preferable for energy absorption performance per unit mass. Less fluctuation in indentation force was achieved in the combination of the hemispherical shell and similar shaped indentor. The consumed energy in the travel length of the indentor equal to the shell height was evaluated. The increase ratio of the energy is prominent when the hemispherical indentor is replaced by a flat-headed one in both shell shapes. Finite element simulation was also conducted. Deformation behaviors were successfully predicted when the kinematic hardening plasticity was introduced in the material model.

27 CFR 9.207 - Outer Coastal Plain.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Outer Coastal Plain. 9.207... Outer Coastal Plain. (a) Name. The name of the viticultural area described in this section is “Outer Coastal Plain”. For purposes of part 4 of this chapter, “Outer Coastal Plain” is a term of viticultural...

Off-shell CHY amplitudes

Energy Technology Data Exchange (ETDEWEB)

Lam, C.S., E-mail: Lam@physics.mcgill.ca [Department of Physics, McGill University, Montreal, Q.C., H3A 2T8 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Yao, York-Peng, E-mail: yyao@umich.edu [Department of Physics, The University of Michigan Ann Arbor, MI 48109 (United States)

2016-06-15

The Cachazo–He–Yuan (CHY) formula for on-shell scattering amplitudes is extended off-shell. The off-shell amplitudes (amputated Green's functions) are Möbius invariant, and have the same momentum poles as the on-shell amplitudes. The working principles which drive the modifications to the scattering equations are mainly Möbius covariance and energy momentum conservation in off-shell kinematics. The same technique is also used to obtain off-shell massive scalars. A simple off-shell extension of the CHY gauge formula which is Möbius invariant is proposed, but its true nature awaits further study.

Hydrogenated CoOx nanowire@Ni(OH)2 nanosheet core-shell nanostructures for high-performance asymmetric supercapacitors

Science.gov (United States)

Zhu, Jianxiao; Huang, Lei; Xiao, Yuxiu; Shen, Leo; Chen, Qi; Shi, Wangzhou

2014-05-01

We report a facile strategy to prepare 3D core-shell nanowire heterostructures with microporous hydrogenated CoOx (H-CoOx) nanowires as the conducting scaffold to support Ni(OH)2 nanosheets. Benefiting from the H-CoOx nanowire core to provide the effective pathway for charge transport and the core-shell heterostructures with synergistic effects, the H-CoOx@Ni(OH)2 core-shell nanowire electrode achieved the specific capacitance of 2196 F g-1 (areal capacitance of 5.73 F cm-2), which is approximately a 1.4-fold enhancement compared with the Co3O4@Ni(OH)2 core-shell nanowires. An aqueous asymmetric supercapacitor (ASC) device was fabricated by using H-CoOx@Ni(OH)2 nanowires as the positive electrode and reduced graphene oxide @Fe3O4 nanocomposites as the negative electrode. The ASCs achieved high energy density (~45.3 W h kg-1 at 1010 W kg-1), high power density (~7080 W kg-1 at 23.4 W h kg-1) and high cycling stability. Furthermore, after charging for ~1 min, one such 22 cm2 ASC device demonstrated to be able to drive a small windmill (0.8 V, 0.1 W) for 20 min. Two such ASCs connected in series can power up a seven-color LED (3.2 V) efficiently.We report a facile strategy to prepare 3D core-shell nanowire heterostructures with microporous hydrogenated CoOx (H-CoOx) nanowires as the conducting scaffold to support Ni(OH)2 nanosheets. Benefiting from the H-CoOx nanowire core to provide the effective pathway for charge transport and the core-shell heterostructures with synergistic effects, the H-CoOx@Ni(OH)2 core-shell nanowire electrode achieved the specific capacitance of 2196 F g-1 (areal capacitance of 5.73 F cm-2), which is approximately a 1.4-fold enhancement compared with the Co3O4@Ni(OH)2 core-shell nanowires. An aqueous asymmetric supercapacitor (ASC) device was fabricated by using H-CoOx@Ni(OH)2 nanowires as the positive electrode and reduced graphene oxide @Fe3O4 nanocomposites as the negative electrode. The ASCs achieved high energy density (~45.3 W h kg-1 at

Ultimate load capacity assessment of reinforced concrete shell structures

International Nuclear Information System (INIS)

Gupta, Amita; Singh, R.K.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

1993-01-01

The objective of this study is to develop capability for prediction of ultimate load capacity of reinforced concrete shell structures. The present finite element code ULCA (Ultimate Load Capacity Assessment) adopts a degenerate concept of formulating general isoparametric shell element with a layered approach in the thickness direction. Different failure modes such as crushing, tensile cracking and reinforcement yielding are recognised for various problems. The structure fails by crushing of concrete when the concrete strain/stress reaches the ultimate stress or strain of concrete. Material nonlinearities as a result of tension cracking, tension stiffening between reinforcement and concrete in cracked region and yielding of reinforcement are considered along with geometric nonlinearity. Thus with this code it is possible to predict the pressure at which the first cracking, first through thickness cracking, first yielding of reinforcement occurs. After validating the code with few bench mark problems for different failure modes a reinforced concrete nuclear containment is analysed for its ultimate capacity and the results are matched with the published results. Further the ultimate load capacity of outer containment wall of Narora Atomic Power Station is predicted. It is observed that containment fails in membrane region and has a sufficient margin against design pressure. (author). 9 refs., 56 figs., 3 tabs., 1 appendix with 4 tabs

New-generation Monte Carlo shell model for the K computer era

International Nuclear Information System (INIS)

Shimizu, Noritaka; Abe, Takashi; Yoshida, Tooru; Otsuka, Takaharu; Tsunoda, Yusuke; Utsuno, Yutaka; Mizusaki, Takahiro; Honma, Michio

2012-01-01

We present a newly enhanced version of the Monte Carlo shell-model (MCSM) method by incorporating the conjugate gradient method and energy-variance extrapolation. This new method enables us to perform large-scale shell-model calculations that the direct diagonalization method cannot reach. This new-generation framework of the MCSM provides us with a powerful tool to perform very advanced large-scale shell-model calculations on current massively parallel computers such as the K computer. We discuss the validity of this method in ab initio calculations of light nuclei, and propose a new method to describe the intrinsic wave function in terms of the shell-model picture. We also apply this new MCSM to the study of neutron-rich Cr and Ni isotopes using conventional shell-model calculations with an inert 40 Ca core and discuss how the magicity of N = 28, 40, 50 remains or is broken. (author)

Light-stimulated cargo release from a core–shell structured nanocomposite for site-specific delivery

International Nuclear Information System (INIS)

Cai, Yun; Ling, Li; Li, Xiaofang; Chen, Meng; Su, Likai

2015-01-01

This paper reported a core–shell structured site-specific delivery system with a light switch triggered by low energy light (λ=510 nm). Its core was composed of supermagnetic Fe 3 O 4 nanoparticles for magnetic guiding and targeting. Its outer shell consisted of mesoporous silica molecular sieve MCM-41 which offered highly ordered hexagonal tunnels for cargo capacity. A light switch N1-(4aH-cyclopenta[1,2-b:5,4-b′]dipyridin-5(5aH)-ylidene)benzene-1, 4-diamine (CBD) was covalently grafted into these hexagonal tunnels, serving as light stimuli acceptor with loading content of 1.1 μM/g. This composite was fully characterized and confirmed by SEM, TEM, XRD patterns, N 2 adsorption/desorption, thermogravimetric analysis, IR, UV–vis absorption and emission spectra. Experimental data suggested that this composite had a core as wide as 150 nm and could be magnetically guided to specific sites. Its hexagonal tunnels were as long as 180 nm. Upon light stimuli of “on” and “off” states, controllable release was observed with short release time of ~900 s (90% capacity). - Graphical abstract: A core–shell structured site-specific delivery system with a light switch triggered by yellow light was constructed. Controllable release was observed with short release time of ~900 s (90% capacity). - Highlights: • A core–shell structured site-specific delivery system was constructed. • It consisted of Fe 3 O 4 core and MCM-41 shell grafted with light switch. • This delivery system was triggered by low energy light. • Controllable release was observed with short release time of ~900 s

Light-stimulated cargo release from a core–shell structured nanocomposite for site-specific delivery

Energy Technology Data Exchange (ETDEWEB)

Cai, Yun; Ling, Li; Li, Xiaofang [Department of Neurology, Affiliated Hospital of Hebei University, Baoding 071000 (China); Chen, Meng [Department of Rheumatology, Affiliated Hospital of Hebei University, Baoding 071000 (China); Su, Likai, E-mail: zhangdong19992003@163.com [Department of Neurology, Affiliated Hospital of Hebei University, Baoding 071000 (China)

2015-03-15

This paper reported a core–shell structured site-specific delivery system with a light switch triggered by low energy light (λ=510 nm). Its core was composed of supermagnetic Fe{sub 3}O{sub 4} nanoparticles for magnetic guiding and targeting. Its outer shell consisted of mesoporous silica molecular sieve MCM-41 which offered highly ordered hexagonal tunnels for cargo capacity. A light switch N1-(4aH-cyclopenta[1,2-b:5,4-b′]dipyridin-5(5aH)-ylidene)benzene-1, 4-diamine (CBD) was covalently grafted into these hexagonal tunnels, serving as light stimuli acceptor with loading content of 1.1 μM/g. This composite was fully characterized and confirmed by SEM, TEM, XRD patterns, N{sub 2} adsorption/desorption, thermogravimetric analysis, IR, UV–vis absorption and emission spectra. Experimental data suggested that this composite had a core as wide as 150 nm and could be magnetically guided to specific sites. Its hexagonal tunnels were as long as 180 nm. Upon light stimuli of “on” and “off” states, controllable release was observed with short release time of ~900 s (90% capacity). - Graphical abstract: A core–shell structured site-specific delivery system with a light switch triggered by yellow light was constructed. Controllable release was observed with short release time of ~900 s (90% capacity). - Highlights: • A core–shell structured site-specific delivery system was constructed. • It consisted of Fe{sub 3}O{sub 4} core and MCM-41 shell grafted with light switch. • This delivery system was triggered by low energy light. • Controllable release was observed with short release time of ~900 s.

Titanium dioxide@polypyrrole core-shell nanowires for all solid-state flexible supercapacitors

Science.gov (United States)

Yu, Minghao; Zeng, Yinxiang; Zhang, Chong; Lu, Xihong; Zeng, Chenghui; Yao, Chenzhong; Yang, Yangyi; Tong, Yexiang

2013-10-01

Herein, we developed a facile two-step process to synthesize TiO2@PPy core-shell nanowires (NWs) on carbon cloth and reported their improved electrochemical performance for flexible supercapacitors (SCs). The fabricated solid-state SC device based on TiO2@PPy core-shell NWs not only has excellent flexibility, but also exhibits remarkable electrochemical performance.Herein, we developed a facile two-step process to synthesize TiO2@PPy core-shell nanowires (NWs) on carbon cloth and reported their improved electrochemical performance for flexible supercapacitors (SCs). The fabricated solid-state SC device based on TiO2@PPy core-shell NWs not only has excellent flexibility, but also exhibits remarkable electrochemical performance. Electronic supplementary information (ESI) available: Experimental details, XRD pattern, FT-IR absorption spectrum and CV curves of TiO2@PPy NWs, and SEM images of the PPy. See DOI: 10.1039/c3nr03578f

Tailored Core Shell Cathode Powders for Solid Oxide Fuel Cells

Energy Technology Data Exchange (ETDEWEB)

Swartz, Scott [NexTech Materials, Ltd.,Lewis Center, OH (United States)

2015-03-23

In this Phase I SBIR project, a “core-shell” composite cathode approach was evaluated for improving SOFC performance and reducing degradation of lanthanum strontium cobalt ferrite (LSCF) cathode materials, following previous successful demonstrations of infiltration approaches for achieving the same goals. The intent was to establish core-shell cathode powders that enabled high performance to be obtained with “drop-in” process capability for SOFC manufacturing (i.e., rather than adding an infiltration step to the SOFC manufacturing process). Milling, precipitation and hetero-coagulation methods were evaluated for making core-shell composite cathode powders comprised of coarse LSCF “core” particles and nanoscale “shell” particles of lanthanum strontium manganite (LSM) or praseodymium strontium manganite (PSM). Precipitation and hetero-coagulation methods were successful for obtaining the targeted core-shell morphology, although perfect coverage of the LSCF core particles by the LSM and PSM particles was not obtained. Electrochemical characterization of core-shell cathode powders and conventional (baseline) cathode powders was performed via electrochemical impedance spectroscopy (EIS) half-cell measurements and single-cell SOFC testing. Reliable EIS testing methods were established, which enabled comparative area-specific resistance measurements to be obtained. A single-cell SOFC testing approach also was established that enabled cathode resistance to be separated from overall cell resistance, and for cathode degradation to be separated from overall cell degradation. The results of these EIS and SOFC tests conclusively determined that the core-shell cathode powders resulted in significant lowering of performance, compared to the baseline cathodes. Based on the results of this project, it was concluded that the core-shell cathode approach did not warrant further investigation.

DS-CDMA system outer loop power control and improvement for multi-service

Institute of Scientific and Technical Information of China (English)

Guan Mingxiang; Guo Qing; Li Xing

2008-01-01

When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control (OLPC) technology has to be adopted to enrich the target signal interference ratio (SIR) and improve the system performance. The existing problems about DS-CDMA outer loop power control for multi-service are introduced and the power control theoretical model is analyzed. System simulation is adopted on how to obtain the theoretical performance and parameter optimization of the power control algorithm. The OLPC algorithm is improved and the performance comparisons between the old algorithm and the improved algorithm are given. The results show good performance of the improved OLPC algorithm and prove the validity of the improved method for multi-service.

Collective effects in isolated atoms (many-body aspects of photoionization process)

International Nuclear Information System (INIS)

Amusia, M.Y.

1983-01-01

This chapter examines outer and intermediate many-electron shells and demonstrates that photoionization is of collective nature because in the atomic reaction to the external electromagnetic field at least all electrons of the ionized subshell take part. Performs the calculation of complex atom photoionization using random phase approximation with exchange (RPAE). Explains that in RPAE the ionization amplitude is presented as a sum of two terms, describing the direct knock-out and the induced one which is connected with a variation of the self-consistent field, caused by polarization of atomic shells under the action of the external field. Discusses collective effects in outer shells; deviation from RPAE prediction in outer shells; excitations ''two electrons-two holes'' and autoionizing states; collective effects in inner shells; and bremsstrahlung. Observes a large number of many-particle effects which manifest themselves practically in all atomic processes. Finds that by correcting and improving the one-electron approximation it becomes possible even in its frame to include much of what seems to be many-electron corrections

A filament wound carbon-carbon composite for impact shell application

International Nuclear Information System (INIS)

Zee, Ralph; Romanoski, Glenn

2000-01-01

The performance and safety of the radioisotope power source depend in part on the thermal and impact properties of the materials used in the general purpose heat source (GPHS) through the use of an impact shell, thermal insulation and an aeroshell. Within the aeroshell are two graphite impact shells, made of fine-weave pierced-fabric (FWPF) that encapsulate four iridium alloy clad isotopic fuel pellets and provides impact protection for the clad. Impact studies conducted at Los Alamos National Laboratory showed that impact shells typically fractured parallel to their longitudinal axis. The objective of this effort is to develop new impact shell concepts with improved performance. An effort to develop alternative carbon-carbon composites for the graphite impact shell was conducted. Eight braided architectures were examined in this study. The effects of the number of graphitization cycles on both the density and circumferential strength of these braided structures were determined. Results show that a filament wound carbon-carbon composite possesses the desired density and circumferential strength important to GPHS

Fabrication of hydrophilic S/In{sub 2}O{sub 3} core–shell nanocomposite for enhancement of photocatalytic performance under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Meng, Sugang; Cao, Zhisheng; Fu, Xianliang [Department of Chemistry, Huaibei Normal University, Anhui Huaibei, 235000 (China); Chen, Shifu, E-mail: chshifu@chnu.edu.cn [Department of Chemistry, Huaibei Normal University, Anhui Huaibei, 235000 (China); Department of Chemistry, Anhui Science and Technology University, Anhui Fengyang, 233100 (China)

2015-01-01

Graphical abstract: - Highlights: • The elemental core–shell heterostructure was reported for the first time. • The hydrophilic core–shell S/In{sub 2}O{sub 3} photocatalyst was prepared by ball milling. • The rate constant of 10% S/In{sub 2}O{sub 3} is 11.6 and 13.5 times that of In{sub 2}O{sub 3} and S. • The hydrophilicity and efficiently separation of carriers are major factor. - Abstract: Recently, elemental semiconductors as new photocatalysts excited by visible light have attracted great attention due to their potential applications for environmental remediation and clean energy generation. However, it is still a challenge to fabricate elemental photocatalysts with high activity and stability. In this paper, a straightforward ball-milling method was carried out to fabricate core–shell S/In{sub 2}O{sub 3} nanocomposite photocatalyst with high performance. The photocatalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) method, photoluminescence spectra (PL) and super-hydrophilic experiment. The results showed that In{sub 2}O{sub 3} nanoparticles were successfully grown round of S blocks and formed core–shell heterostructures. The 10% S/In{sub 2}O{sub 3} core–shell nanocomposite exhibited the highest photocatalytic activity for degradation of rhodamine B (RhB) under visible light irradiation. The reaction rate constant (k) of the 10% S/In{sub 2}O{sub 3} core–shell nanocomposite is about 8.7 times as high as the sum of pure In{sub 2}O{sub 3} and S because of the formation of core–shell S/In{sub 2}O{sub 3} heterostructures, which might remedy the drawbacks of poor hydrophilicity of S, enhance visible light absorption and separate the photogenerated carriers efficiently. Furthermore, the mechanism of influence on the photocatalytic activity of the S

Mass spectrometric identification of Au68(SR)34 molecular gold nanoclusters with 34-electron shell closing.

Science.gov (United States)

Dass, Amala

2009-08-26

The molecular formula Au(68)(SCH(2)CH(2)Ph)(34) has been assigned to the 14 kDa nanocluster using MALDI-TOF mass spectrometry. The 34-electron shell closing in a macroscopically obtained thiolated gold nanocluster is demonstrated. The Au(68) nanocluster is predicted to have a 49 atom Marks decahedral core with 19 inner core atoms and 30 outer atoms chelating with the staple motifs. The nanoclusters' predicted formulation is [Au](19+30) [Au(SR)(2)](11) [Au(2)(SR)(3)](4).

LCAO calculations of SrTiO{sub 3} nanotubes

Energy Technology Data Exchange (ETDEWEB)

Evarestov, Robert; Bandura, Andrei, E-mail: re1973@re1973.spb.edu [Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetsky Ave., 198504, Petrodvorets (Russian Federation)

2011-06-23

The large-scale first-principles simulation of the structure and stability of SrTiO{sub 3} nanotubes is performed for the first time using the periodic PBE0 LCAO method. The initial structures of the nanotubes have been obtained by the rolling up of the stoichiometric SrTiO{sub 3} slabs consisting of two or four alternating (001) SrO and TiO{sub 2} atomic planes. Nanotubes (NTs) with chiralities (n,0) and (n,n) have been studied. Two different NTs were constructed for each chirality: (I) with SrO outer shell, and (II) with TiO{sub 2} outer shell. Positions of all atoms have been optimized to obtain the most stable NT structure . In the majority of considered cases the inner or outer TiO{sub 2} shells of NT undergo a considerable reconstruction due to shrinkage or stretching of interatomic distances in the initial cubic perovskite structure. There were found two types of surface reconstruction: (1) breaking of Ti-O bonds with creating of Ti = O titanyl groups in outer surface; (2) inner surface folding due to Ti-O-Ti bending. Based on strain energy calculations the largest stability was found for (n,0) NTs with TiO{sub 2} outer shell.

LCAO calculations of SrTiO3 nanotubes

International Nuclear Information System (INIS)

Evarestov, Robert; Bandura, Andrei

2011-01-01

The large-scale first-principles simulation of the structure and stability of SrTiO 3 nanotubes is performed for the first time using the periodic PBE0 LCAO method. The initial structures of the nanotubes have been obtained by the rolling up of the stoichiometric SrTiO 3 slabs consisting of two or four alternating (001) SrO and TiO 2 atomic planes. Nanotubes (NTs) with chiralities (n,0) and (n,n) have been studied. Two different NTs were constructed for each chirality: (I) with SrO outer shell, and (II) with TiO 2 outer shell. Positions of all atoms have been optimized to obtain the most stable NT structure . In the majority of considered cases the inner or outer TiO 2 shells of NT undergo a considerable reconstruction due to shrinkage or stretching of interatomic distances in the initial cubic perovskite structure. There were found two types of surface reconstruction: (1) breaking of Ti-O bonds with creating of Ti = O titanyl groups in outer surface; (2) inner surface folding due to Ti-O-Ti bending. Based on strain energy calculations the largest stability was found for (n,0) NTs with TiO 2 outer shell.

Addressing Challenges and Scalability in the Synthesis of Thin Uniform Metal Shells on Large Metal Nanoparticle Cores: Case Study of Ag-Pt Core-Shell Nanocubes.

Science.gov (United States)

Aslam, Umar; Linic, Suljo

2017-12-13

Bimetallic nanoparticles in which a metal is coated with an ultrathin (∼1 nm) layer of a second metal are often desired for their unique chemical and physical properties. Current synthesis methods for producing such core-shell nanostructures often require incremental addition of a shell metal precursor which is rapidly reduced onto metal cores. A major shortcoming of this approach is that it necessitates precise concentrations of chemical reagents, making it difficult to perform at large scales. To address this issue, we considered an approach whereby the reduction of the shell metal precursor was controlled through in situ chemical modification of the precursor. We used this approach to develop a highly scalable synthesis for coating atomic layers of Pt onto Ag nanocubes. We show that Ag-Pt core-shell nanostructures are synthesized in high yields and that these structures effectively combine the optical properties of the plasmonic Ag nanocube core with the surface properties of the thin Pt shell. Additionally, we demonstrate the scalability of the synthesis by performing a 10 times scale-up.

Cross Sections for K-shell X-ray Production by Hydrogen and Helium Ions in Elements from Beryllium to Uranium

International Nuclear Information System (INIS)

Lapicki, G.

1989-01-01

Experimental cross sections for K-shell x-ray production by hydrogen and helium ions (Z 1 = 1,2) in target atoms from beryllium to uranium (Z 2 = 4--92 ) are tabulated as compiled (7418 cross sections) from the literature (161 references were found) with the search for the data terminated in January 1988. These cross sections are compared with predictions of the first Born approximation and ECPSSR theory for inner-shell ionization. The ECPSSR accounts for the energy loss (E) and Coulomb deflection (C) of the projectile ion as well as for the perturbed stationary state (PSS) and relativistic (R) nature of the target's inner-shell electron.While the first Born approximation generally overestimates the data by orders of magnitude, the ECPSSR theory is confirmed to be, on the average, in agreement with the experiment to within 10%--20%. For light and heavy target atoms, however, systematic and opposite deviations are found in the low projectile-velocity regime. These deviations are associated with the influence of multiple outer-shell ionizations on the fluorescence yields of light elements, particularly in ionization by helium ions, and with the inaccuracy of the ECPSSR theory in the reproduction of relativistic calculations for ionization of heavy elements. The remaining discrepancies at moderate projectile velocities are prima facie attributed to inadequacies of a screened hydrogenic description for the K-shell electron

Implementation of Localized Corrosion in the Performance Assessment Model for Yucca Mountain

International Nuclear Information System (INIS)

Jain, V.; SEVOUGIAN, D.S.; MATTIE, P.D.; MACKINNON, R.J.

2005-01-01

A total system performance assessment (TSPA) model has been developed to analyze the ability of the natural and engineered barriers of the Yucca Mountain repository to isolate nuclear waste for the 10,000-year period following repository closure. The principal features of the engineered barrier system (EBS) are emplacement tunnels (or ''drifts'') containing a two-layer waste package (WP) for waste containment and a titanium drip shield to protect the waste package from seeping water and falling rock. The 20-mm-thick outer shell of the WP is composed of Alloy 22, a highly corrosion-resistant nickel-based alloy, while the 50-mm inner shell is composed of 316 stainless steel (modified with lower carbon and nitrogen compositions), whose primary purpose is to provide structural strength. The barrier function of the EBS is to isolate the waste from the migrating water with its associated chemical conditions that eventually lead to degradation of the waste packages and mobilization of the radionuclides within the packages

Large-area super-resolution optical imaging by using core-shell microfibers

Science.gov (United States)

Liu, Cheng-Yang; Lo, Wei-Chieh

2017-09-01

We first numerically and experimentally report large-area super-resolution optical imaging achieved by using core-shell microfibers. The particular spatial electromagnetic waves for different core-shell microfibers are studied by using finite-difference time-domain and ray tracing calculations. The focusing properties of photonic nanojets are evaluated in terms of intensity profile and full width at half-maximum along propagation and transversal directions. In experiment, the general optical fiber is chemically etched down to 6 μm diameter and coated with different metallic thin films by using glancing angle deposition. The direct imaging of photonic nanojets for different core-shell microfibers is performed with a scanning optical microscope system. We show that the intensity distribution of a photonic nanojet is highly related to the metallic shell due to the surface plasmon polaritons. Furthermore, large-area super-resolution optical imaging is performed by using different core-shell microfibers placed over the nano-scale grating with 150 nm line width. The core-shell microfiber-assisted imaging is achieved with super-resolution and hundreds of times the field-of-view in contrast to microspheres. The possible applications of these core-shell optical microfibers include real-time large-area micro-fluidics and nano-structure inspections.

Detached dust shell around Wolf-Rayet star WR60-6 in the young stellar cluster VVV CL036

Energy Technology Data Exchange (ETDEWEB)

Borissova, J.; Amigo, P.; Kurtev, R. [Departamento de Física y Astronomía, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Casilla 5030 (Chile); Kumar, M. S. N. [Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Chené, A.-N. [Gemini Observatory, Northern Operations Center, 670 North A' ohoku Place Hilo, HI 96720 (United States); Minniti, D., E-mail: jura.borissova@uv.cl [Pontificia Universidad Católica de Chile, Facultad de Física, Departamento de Astronomía y Astrofísica, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile)

2014-01-01

The discovery of a detached dust shell around the Wolf-Rayet (WR) star WR60-6 in the young stellar cluster VVV CL036 is reported. This shell is uncovered through the Spitzer-MIPS 24 μm image, where it appears brightest, and it is invisible at shorter wavelengths. Using new APEX observations and other data available from the literature, we have estimated some of the shell parameters: the inner and outer radii of 0.15 and 0.90 pc, respectively; the overall systemic velocity of the molecular {sup 12}CO(3 → 2) emission of –45.7 ± 2.3 km s{sup –1}; an expansion velocity of the gas of 16.3 ± 1 km s{sup –1}; the dust temperature and opacity of 122 ± 12 K and 1.04, respectively; and an age of 2.8 × 10{sup 4} yr. The WR star displays some cyclic variability. The mass computed for the WR60-6 nebula indicates that the material was probably ejected during its previous stages of evolution. In addition, we have identified a bright spot very close to the shell, which can be associated with the Midcourse Space Experiment source G312.13+00.20.

Maximizing 1D “like” implosion performance for inertial confinement fusion science

Energy Technology Data Exchange (ETDEWEB)

Kline, John L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-07-15

While the march towards achieving indirectly driven inertial confinement fusion at the NIF has made great progress, the experiments show that multi-dimensional effects still dominate the implosion performance. Low mode implosion symmetry and hydrodynamic instabilities seed by capsule mounting features appear to be two key limiting factors for implosion performance. One reason these factors have a large impact on the performance of ICF implosions is the high convergence required to achieve high fusion gains. To tackle these problems, a predictable implosion platform is needed meaning experiments must trade-off high gain for performance. To this end, LANL has adopted three main approaches to develop a 1D implosion platform where 1D means high yield over 1D clean calculations. Taking advantage of the properties of beryllium capsules, a high adiabat, low convergence platform is being developed. The higher drive efficiency for beryllium enables larger case-to-capsule ratios to improve symmetry at the expense of drive. Smaller capsules with a high adiabat drive are expected to reduce the convergence and thus increase predictability. The second approach is liquid fuel layers using wetted foam targets. With liquid fuel layers, the initial mass in the hot spot can be controlled via the target fielding temperature which changes the liquid vapor pressure. Varying the initial hot spot mass via the vapor pressure controls the implosion convergence and minimizes the need to vaporize the dense fuel layer during the implosion to achieve ignition relevant hot spot densities. The last method is double shell targets. Unlike hot spot ignition, double shells ignite volumetrically. The inner shell houses the DT fuel and the convergence of this cavity is relatively small compared to hot spot ignition. Radiation trapping and the longer confinement times relax the conditions required to ignite the fuel. Key challenges for double shell targets are coupling the momentum of the outer shell to

Self-Assembled Core-Shell CdTe/Poly(3-hexylthiophene) Nanoensembles as Novel Donor-Acceptor Light-Harvesting Systems.

Science.gov (United States)

Istif, Emin; Kagkoura, Antonia; Hernandez-Ferrer, Javier; Stergiou, Anastasios; Skaltsas, Theodosis; Arenal, Raul; Benito, Ana M; Maser, Wolfgang K; Tagmatarchis, Nikos

2017-12-27

The self-assembly of novel core-shell nanoensembles consisting of regioregular poly(3-hexylthiophene) nanoparticles (P3HT NPs ) of 100 nm as core and semiconducting CdTe quantum dots (CdTe QDs ) as shell with a thickness of a few tens of nanometers was accomplished by employing a reprecipitation approach. The structure, morphology, and composition of CdTe QDs /P3HT NPs nanoensembles were confirmed by high-resolution scanning transmission microscopy and dynamic light-scattering studies. Intimate interface contact between the CdTe QDs shell and the P3HT NPs core leads to the stabilization of the CdTe QDs /P3HT NPs nanoensemble as probed by the steady-state absorption spectroscopy. Effective quenching of the characteristic photoluminescence of CdTe QDs at 555 nm, accompanied by simultaneous increase in emission of P3HT NPs at 660 and 720 nm, reveals photoinduced charge-transfer processes. Probing the redox properties of films of CdTe QDs /P3HT NPs further proves the formation of a stabilized core-shell system in the solid state. Photoelectrochemical assays on CdTe QDs /P3HT NPs films show a reversible on-off photoresponse at a bias voltage of +0.8 V with a 3 times increased photocurrent compared to CdTe QDs . The improved charge separation is directly related to the unique core-shell configuration, in which the outer CdTe QDs shell forces the P3HT NPs core to effectively act as electron acceptor. The creation of novel donor-acceptor core-shell hybrid materials via self-assembly is transferable to other types of conjugated polymers and semiconducting nanoparticles. This work, therefore, opens new pathways for the design of improved optoelectronic devices.

Performance Enhancement of a Sulfur/Carbon Cathode by Polydopamine as an Efficient Shell for High-Performance Lithium-Sulfur Batteries.

Science.gov (United States)

Zhang, Xuqing; Xie, Dong; Zhong, Yu; Wang, Donghuang; Wu, Jianbo; Wang, Xiuli; Xia, Xinhui; Gu, Changdong; Tu, Jiangping

2017-08-04

Lithium-sulfur batteries (LSBs) are considered to be among the most promising next-generation high-energy batteries. It is a consensus that improving the conductivity of sulfur cathodes and impeding the dissolution of lithium polysulfides are two key accesses to high-performance LSBs. Herein we report a sulfur/carbon black (S/C) cathode modified by self-polymerized polydopamine (pDA) with the assistance of polymerization treatment. The pDA acts as a novel and effective shell on the S/C cathode to stop the shuttle effect of polysulfides. By the synergistic effect of enhanced conductivity and multiple blocking effect for polysulfides, the S/C@pDA electrode exhibits improved electrochemical performances including large specific capacity (1135 mAh g -1 at 0.2 C), high rate capability (533 mAh g -1 at 5 C) and long cyclic life (965 mAh g -1 after 200 cycles). Our smart design strategy may promote the development of high-performance LSBs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Template-free synthesis of hierarchical yolk-shell Co and N codoped porous carbon microspheres with enhanced performance for oxygen reduction reaction

Science.gov (United States)

Chao, Shujun; Cui, Qian; Wang, Kui; Bai, Zhengyu; Yang, Lin; Qiao, Jinli

2015-08-01

The structures and compositions of materials have important influences on their performance. Herein, hierarchically structured yolk-shell Co and N codoped porous carbon microspheres (YS-Co/N-PCMs) have been successfully synthesized by using low-cost melamine, formaldehyde and cobalt acetate as raw materials via a facile template-free hydrothermal method and a subsequent pyrolysis. The formation process of the yolk-shell precursor is systematically investigated, involving a morphological evolution process from solid microspheres, ultrathin and wrinkled shells wrap, to yolk-shell structure formation. More importantly, the unique structure combines the favorable features towards oxygen reduction reaction (ORR), such as high surface area, sufficient Co-Nx and graphitic N active sites and suitable pore structures. As a result, the YS-Co/N-PCMs catalyst shows high catalytic activity for ORR in alkaline media for fuel cells, which not only outperforms commercial Pt-based catalysts in terms of resistance to methanol crossover and long-time stability, but is also better than many non-precious metal doped carbon-based catalysts reported previously. In addition, the YS-Co/N-PCMs catalyst also has high catalytic activity toward oxygen evolution reaction (OER). Therefore, the YS-Co/N-PCMs catalyst may serve as a promising alternative to Pt/C catalyst for ORR and OER in alkaline media.

Oxygen-rich hierarchical porous carbon derived from artemia cyst shells with superior electrochemical performance.

Science.gov (United States)

Zhao, Yufeng; Ran, Wei; He, Jing; Song, Yanfang; Zhang, Chunming; Xiong, Ding-Bang; Gao, Faming; Wu, Jinsong; Xia, Yongyao

2015-01-21

In this study, three-dimensional (3D) hierarchical porous carbon with abundant functional groups is produced through a very simple low-cost carbonization of Artemia cyst shells. The unique hierarchical porous structure of this material, combining large numbers of micropores and macropores, as well as reasonable amount of mesopores, is proven favorable to capacitive behavior. The abundant oxygen functional groups from the natural carbon precursor contribute stable pseudocapacitance. As-prepared sample exhibits high specific capacitance (369 F g(-1) in 1 M H2SO4 and 349 F g(-1) in 6 M KOH), excellent cycling stability with capacitance retention of 100% over 10 000 cycles, and promising rate performance. This work not only describes a simple way to produce high-performance carbon electrode materials for practical application, but also inspires an idea for future structure design of porous carbon.

Dossier Shell Eco-Marathon; Dossier Shell Eco-Marathon

Energy Technology Data Exchange (ETDEWEB)

Matla, P.

2012-05-15

Three articles address subjects concerning the annual race with highly energy efficient cars: the Shell Eco-Marathon. [Dutch] In 3 artikelen wordt aandacht besteed aan de ontwerpen voor de jaarlijkse race met superzuinige auto's, de Shell Eco-Marathon.

Synthesis of bimetallic Pt-Pd core-shell nanocrystals and their high electrocatalytic activity modulated by Pd shell thickness

Science.gov (United States)

Li, Yujing; Wang, Zhi Wei; Chiu, Chin-Yi; Ruan, Lingyan; Yang, Wenbing; Yang, Yang; Palmer, Richard E.; Huang, Yu

2012-01-01

Bimetallic Pt-Pd core-shell nanocrystals (NCs) are synthesized through a two-step process with controlled Pd thickness from sub-monolayer to multiple atomic layers. The oxygen reduction reaction (ORR) catalytic activity and methanol oxidation reactivity of the core-shell NCs for fuel cell applications in alkaline solution are systematically studied and compared based on different Pd thickness. It is found that the Pd shell helps to reduce the over-potential of ORR by up to 50mV when compared to commercial Pd black, while generating up to 3-fold higher kinetic current density. The carbon monoxide poisoning test shows that the bimetallic NCs are more resistant to the CO poisoning than Pt NCs and Pt black. It is also demonstrated that the bimetallic Pt-Pd core-shell NCs can enhance the current density of the methanol oxidation reaction, lowering the over-potential by 35 mV with respect to the Pt core NCs. Further investigation reveals that the Pd/Pt ratio of 1/3, which corresponds to nearly monolayer Pd deposition on Pt core NCs, gives the highest oxidation current density and lowest over-potential. This study shows for the first time the systematic investigation of effects of Pd atomic shells on Pt-Pd bimetallic nanocatalysts, providing valuable guidelines for designing high-performance catalysts for fuel cell applications.Bimetallic Pt-Pd core-shell nanocrystals (NCs) are synthesized through a two-step process with controlled Pd thickness from sub-monolayer to multiple atomic layers. The oxygen reduction reaction (ORR) catalytic activity and methanol oxidation reactivity of the core-shell NCs for fuel cell applications in alkaline solution are systematically studied and compared based on different Pd thickness. It is found that the Pd shell helps to reduce the over-potential of ORR by up to 50mV when compared to commercial Pd black, while generating up to 3-fold higher kinetic current density. The carbon monoxide poisoning test shows that the bimetallic NCs are more

WO3–x@Au@MnO2 core–shell nanowires on carbon fabric for high-performance flexible supercapacitors.

Science.gov (United States)

Lu, Xihong; Zhai, Teng; Zhang, Xianghui; Shen, Yongqi; Yuan, Longyan; Hu, Bin; Gong, Li; Chen, Jian; Gao, Yihua; Zhou, Jun; Tong, Yexiang; Wang, Zhong Lin

2012-02-14

WO3–x@Au@MnO2 core–shell nanowires (NWs) are synthesized on a flexible carbon fabric and show outstanding electrochemical performance in supercapacitors such as high specific capacitance, good cyclic stability, high energy density, and high power density. These results suggest that the WO3–x@Au@MnO2 NWs have promising potential for use in high-performance flexible supercapacitors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Outer grid strap protruding spring repair apparatus

International Nuclear Information System (INIS)

Widener, W.H.

1987-01-01

This patent describes a nuclear fuel assembly grid spring repair apparatus for repairing a spring formed on an outer strap of a fuel assembly grid and having a portion protruding outwardly beyond the strap, the apparatus comprising: (a) a support frame defining an opening and having means defining a guide channel extending along the opening in a first direction; (b) means mounted on the frame and being adjustable for attaching the frame to the outer strap of the support grid so that the frame opening is aligned with the outwardly protruding spring on the outer strap; (c) an outer slide having a passageway defined therethrough and being mounted in the guide channel for reciprocable movement along the frame opening in the first direction for aligning the passageway with the outwardly protruding portion of the spring on the outer strap. The outer slide also has means defining a guide way extending along the passageway in a second direction generally orthogonal to the first direction; (d) a spring reset mechanism being operable for resetting the protruding spring to a nonprotruding position relative to the outer strap when the mechanism is aligned with the protruding portion of the spring; and (e) an inner slide supporting the spring reset mechanism and being mounted to the guide way for reciprocable movement along the passageway of the outer slide in the second direction for aligning the spring reset mechanism with the protruding portion of the spring on the outer strap

Dominant thermogravimetric signatures of lignin in cashew shell as compared to cashew shell cake.

Science.gov (United States)

Gangil, Sandip

2014-03-01

Dominant thermogravimetric signatures related to lignin were observed in cashew shell as compared to these signatures in cashew shell cake. The phenomenon of weakening of lignin from cashew shell to cashew shell cake was explained on the basis of changes in the activation energies. The pertinent temperature regimes responsible for the release of different constituents of both the bio-materials were identified and compared. The activation energies of cashew shell and cashew shell cake were compared using Kissinger-Akahira-Sunose method. Thermogravimetric profiling of cashew shell and cashew shell cake indicated that these were different kinds of bio-materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

High performance and durability of order-structured cathode catalyst layer based on TiO{sub 2}@PANI core-shell nanowire arrays

Energy Technology Data Exchange (ETDEWEB)

Chen, Ming; Wang, Meng; Yang, Zhaoyi [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Wang, Xindong, E-mail: echem@ustb.edu.cn [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China)

2017-06-01

Highlights: • TiO{sub 2}@PANI core-shell nanowire arrays were prepared and applied as catalyst support. • As-prepared Pt-TiO{sub 2}@PANI core-shell nanowire arrays were applied as order-structured cathode catalyst layer. • The novel cathode catalyst structure without Nafion{sup ®} ionomer enhance the performance and durability of PEMFC. - Abstract: In this paper, an order-structured cathode catalyst layer consisting of Pt-TiO{sub 2}@PANI core-shell nanowire arrays that in situ grown on commercial gas diffusion layer (GDL) are prepared and applied to membrane electrode assembly (MEA) of proton exchange membrane fuel cell (PEMFC). In order to prepare the TiO{sub 2}@PANI core-shell nanowire arrays with suitable porosity and prominent conductivity, the morphologies of the TiO{sub 2} nanoarray and electrochemical polymerization process of aniline are schematically investigated. The MEA with order-structured cathode catalyst layer is assembled in the single cell to evaluate the electrochemical performance and durability of PEMFC. As a result, the PEMFC with order-structured cathode catalyst layer shows higher peak power density (773.54 mW cm{sup −2}) than conventional PEMFC (699.30 mW cm{sup −2}). Electrochemically active surface area (ECSA) and charge transfer impedance (R{sub ct}) are measured before and after accelerated degradation test (ADT), and the corresponding experimental results indicate the novel cathode structure exhibits a better stability with respect to conventional cathode. The enhanced electrochemical performance and durability toward PEMFC can be ascribed to the order-structured cathode nanoarray structure with high specific surface area increases the utilization of catalyst and reduces the tortuosity of transport pathways, and the synergistic effect between TiO{sub 2}@PANI support and Pt nanoparticles promotes the high efficiency of electrochemical reaction and improves the stability of catalyst. This research provides a facile and

Dual-Shell Fluorescent Nanoparticles for Self-Monitoring of pH-Responsive Molecule-Releasing in a Visualized Way.

Science.gov (United States)

Yang, Lingang; Cui, Chuanfeng; Wang, Lingzhi; Lei, Juying; Zhang, Jinlong

2016-07-27

The rational design and controlled synthesis of a smart device with flexibly tailored response ability is all along desirable for bioapplication but long remains a considerable challenge. Here, a pH-stimulated valve system with a visualized "on-off" mode is constructed through a dual-shell fluorescence resonance energy transfer (FRET) strategy. The dual shells refer to carbon dots and fluorescent molecules embedded polymethacrylic acid (F-PMAA) layers successively coating around a SiO2 core (ca. 120 nm), which play the roles as energy donor and acceptor, respectively. The total thickness of the dual-shell in the solid composite is ca. 10 nm. The priorities of this dual-shell FRET nanovalve stem from three facts: (1) the thin shell allows the formation of efficient FRET system without chemical bonding between energy donor and acceptor; (2) the maximum emission wavelength of CD layer is tunable in the range of 400-600 nm, thus providing a flexible energy donor for a wide variety of energy acceptors; (3) the outer F-PMAA shell with a pH-sensitive swelling-shrinking (on-off) behavior functions as a valve for regulating the FRET process. As such, a sensitive and stable pH ratiometric sensor with a working pH range of 3-6 has been built by simply encapsulating pH-responsive fluorescein isothiocyanate (FITC) into PMAA; a pH-dependent swelling-shrinking shuttle carrier with a finely controllable molecule-release behavior has been further fabricated using rhodamine B isothiocyanate (RBITC) as the energy donor and model guest molecule. Significantly, the controlled releasing process is visually self-monitorable.

Shell-like structures

CERN Document Server

Altenbach, Holm

2011-01-01

In this volume, scientists and researchers from industry discuss the new trends in simulation and computing shell-like structures. The focus is put on the following problems: new theories (based on two-dimensional field equations but describing non-classical effects), new constitutive equations (for materials like sandwiches, foams, etc. and which can be combined with the two-dimensional shell equations), complex structures (folded, branching and/or self intersecting shell structures, etc.) and shell-like structures on different scales (for example: nano-tubes) or very thin structures (similar

A login shell interface for INFN-GRID

Energy Technology Data Exchange (ETDEWEB)

Pardi, S [INFN - Sezione di Napoli, Complesso di Monte S.Angelo - Via Cintia 80126 Napoli (Italy); Calloni, E; Rosa, R De; Garufi, F; Milano, L; Russo, G [Universita degli Studi di Napoli ' Federico M' , Dipartimento di Scienze Fisiche, Complesso di Monte S.Angelo - Via Cintia 80126 Napoli (Italy)], E-mail: silvio.pardi@na.infn.it

2008-12-15

The user interface is a crucial service to guarantee the Grid accessibility. The goal to achieve, is the implementation of an environment able to hide the grid complexity and offer a familiar interface to the final user. Currently many graphical interfaces have been proposed to simplify the grid access, but the GUI approach appears not very congenital to UNIX developers and users accustomed to work with command line interface. In 2004 the GridShell project proposed an extension of popular UNIX shells such as TCSH and BASH with features supporting Grid computing. Starting from the ideas included in GridShell, we propose IGSH (INFN-GRID SHELL) a new login shell for the INFN-GRID middleware, that interact with the Resource Broker services and integrates in a 'naturally way' the grid functionality with a familiar interface. The architecture of IGSH is very simple, it consist of a software layer on the top of the INFN-GRID middleware layer. When some operation is performed by the user, IGSH takes in charge to parse the syntax and translate it in the correspondents INFN-GRID commands according to some semantic rules specified in the next sections. The final user interacts with the underlying distributed infrastructure by using IGSH instead of his default login shell, with the sensation to work on a local machine.

A login shell interface for INFN-GRID

International Nuclear Information System (INIS)

Pardi, S; Calloni, E; Rosa, R De; Garufi, F; Milano, L; Russo, G

2008-01-01

The user interface is a crucial service to guarantee the Grid accessibility. The goal to achieve, is the implementation of an environment able to hide the grid complexity and offer a familiar interface to the final user. Currently many graphical interfaces have been proposed to simplify the grid access, but the GUI approach appears not very congenital to UNIX developers and users accustomed to work with command line interface. In 2004 the GridShell project proposed an extension of popular UNIX shells such as TCSH and BASH with features supporting Grid computing. Starting from the ideas included in GridShell, we propose IGSH (INFN-GRID SHELL) a new login shell for the INFN-GRID middleware, that interact with the Resource Broker services and integrates in a 'naturally way' the grid functionality with a familiar interface. The architecture of IGSH is very simple, it consist of a software layer on the top of the INFN-GRID middleware layer. When some operation is performed by the user, IGSH takes in charge to parse the syntax and translate it in the correspondents INFN-GRID commands according to some semantic rules specified in the next sections. The final user interacts with the underlying distributed infrastructure by using IGSH instead of his default login shell, with the sensation to work on a local machine.

Thermogravimetric characterization and gasification of pecan nut shells.

Science.gov (United States)

Aldana, Hugo; Lozano, Francisco J; Acevedo, Joaquín; Mendoza, Alberto

2015-12-01

This study focuses on the evaluation of pecan nut shells as an alternative source of energy through pyrolysis and gasification. The physicochemical characteristics of the selected biomass that can influence the process efficiency, consumption rates, and the product yield, as well as create operational problems, were determined. In addition, the thermal decomposition kinetics necessary for prediction of consumption rates and yields were determined. Finally, the performance of a downdraft gasifier fed with pecan nut shells was analyzed in terms of process efficiency and exit gas characteristics. It was found that the pyrolytic decomposition of the nut shells can be modeled adequately using a single equation considering two independent parallel reactions. The performance of the gasification process can be influenced by the particle size and air flow rate, requiring a proper combination of these parameters for reliable operation and production of a valuable syngas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extensions to a nonlinear finite-element axisymmetric shell model based on Reissner's shell theory

International Nuclear Information System (INIS)

Cook, W.A.

1981-01-01

Extensions to shell analysis not usually associated with shell theory are described in this paper. These extensions involve thick shells, nonlinear materials, a linear normal stress approximation, and a changing shell thickness. A finite element shell-of-revolution model has been developed to analyze nuclear material shipping containers under severe impact conditions. To establish the limits for this shell model, the basic assumptions used in its development were studied; these are listed in this paper. Several extensions were evident from the study of these limits: a thick shell, a plastic hinge, and a linear normal stress

Performance of fly ash based geopolymer incorporating palm kernel shell for lightweight concrete

Science.gov (United States)

Razak, Rafiza Abd; Abdullah, Mohd Mustafa Al Bakri; Yahya, Zarina; Jian, Ang Zhi; Nasri, Armia

2017-09-01

A concrete which cement is totally replaced by source material such as fly ash and activated by highly alkaline solutions is known as geopolymer concrete. Fly ash is the most common source material for geopolymer because it is a by-product material, so it can get easily from all around the world. An investigation has been carried out to select the most suitable ingredients of geopolymer concrete so that the geopolymer concrete can achieve the desire compressive strength. The samples were prepared to determine the suitable percentage of palm kernel shell used in geopolymer concrete and cured for 7 days in oven. After that, other samples were prepared by using the suitable percentage of palm kernel shell and cured for 3, 14, 21 and 28 days in oven. The control sample consisting of ordinary Portland cement and palm kernel shell and cured for 28 days were prepared too. The NaOH concentration of 12M, ratio Na2SiO3 to NaOH of 2.5, ratio fly ash to alkaline activator solution of 2.0 and ratio water to geopolymer of 0.35 were fixed throughout the research. The density obtained for the samples were 1.78 kg/m3, water absorption of 20.41% and the compressive strength of 14.20 MPa. The compressive strength of geopolymer concrete is still acceptable as lightweight concrete although the compressive strength is lower than OPC concrete. Therefore, the proposed method by using fly ash mixed with 10% of palm kernel shell can be used to design geopolymer concrete.

Design, fabrication and testing of a prototype stressed-shell fuel isolation container

International Nuclear Information System (INIS)

Crosthwaite, J.L.; Barrie, J.N.; Nuttall, K.

1982-07-01

Atomic Energy of Canada Limited is conducting and coordinating research into the development of engineered barriers for the disposal of unreprocessed irradiated fuel within a deep, stable geologic vault. In one approach, a containment shell of corrosion-resistant metal is proposed as the principal barrier to radionuclide release, giving a high probability of containment for at least 300 years, thus ensuring isolation of nearly all fission products for their hazardous lives. The simplest concept is the 'stressed-shell' container, designed with sufficient shell thickness to withstand the hydrostatic pressure within a 1000-m deep disposal vault postulated to have flooded with groundwater. This report describes the design, fabrication, analysis and hydrostatic testing of a full-scale stressed-shell prototype. The report concludes that the deformation and collapse performance of stressed-shell designs, based on short-term mechanical properties be modelled adequately by BOSOR 5, a commercially available stress-strain computer program. If the stressed-shell concept is retained as a viable fuel isolation concept, future analyses should include an assessment of the role of material creep on long-term container performance

Incorporation of squalene into rod outer segments

International Nuclear Information System (INIS)

Keller, R.K.; Fliesler, S.J.

1990-01-01

We have reported previously that squalene is the major radiolabeled nonsaponifiable lipid product derived from [ 3 H]acetate in short term incubations of frog retinas. In the present study, we demonstrate that newly synthesized squalene is incorporated into rod outer segments under similar in vitro conditions. We show further that squalene is an endogenous constituent of frog rod outer segment membranes; its concentration is approximately 9.5 nmol/mumol of phospholipid or about 9% of the level of cholesterol. Pulse-chase experiments with radiolabeled precursors revealed no metabolism of outer segment squalene to sterols in up to 20 h of chase. Taken together with our previous absolute rate studies, these results suggest that most, if not all, of the squalene synthesized by the frog retina is transported to rod outer segments. Synthesis of protein is not required for squalene transport since puromycin had no effect on squalene incorporation into outer segments. Conversely, inhibition of isoprenoid synthesis with mevinolin had no effect on the incorporation of opsin into the outer segment. These latter results support the conclusion that the de novo synthesis and subsequent intracellular trafficking of opsin and isoprenoid lipids destined for the outer segment occur via independent mechanisms

Performance of a Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

Science.gov (United States)

Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

2014-01-01

The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft² prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.

Study on modal characteristics of perforated shell using effective Young's modulus

International Nuclear Information System (INIS)

Jhung, Myung Jo; Yu, Seon Oh

2011-01-01

Research highlights: → The effective Young's modulus of perforated shell is proposed for modal analysis. → The penetration pattern is almost negligible for effective elastic constants. → The frequency of perforated shell decreases significantly due to the hole effect. - Abstract: For the perforated cylindrical shell submerged in fluid, it is almost impossible to develop a finite element model due to the necessity of the fine meshing of the shell and the fluid at the same time. This necessitates the use of solid shell with effective material properties. Unfortunately the effective elastic constants are not found in any references even though the ASME code is suggesting those for perforated plate. Therefore in this study the effective material properties of perforated shell are suggested by performing several finite element analyses with respect to the ligament efficiencies.

Synthesis of Ni-SiO2/silicalite-1 core-shell micromembrane reactors and their reaction/diffusion performance

KAUST Repository

Khan, Easir A.

2010-12-15

Core-shell micromembrane reactors are a novel class of materials where a catalyst and a shape-selective membrane are synergistically housed in a single particle. In this work, we report the synthesis of micrometer -sized core-shell particles containing a catalyst core and a thin permselective zeolite shell and their application as a micromembrane reactor for the selective hydrogenation of the 1-hexene and 3,3-dimethyl-1-butene isomers. The bare catalyst, which is made from porous silica loaded with catalytically active nickel, showed no reactant selectivity between hexene isomers, but the core-shell particles showed high selectivities up to 300 for a 1-hexene conversion of 90%. © 2010 American Chemical Society.

FABRICATION AND PROPERTIES OVERCOATED RESORCINOL-FORMALDEHYDE SHELLS FOR OMEGA EXPERIMENTS

International Nuclear Information System (INIS)

NIKROO, A; CZECHOWICZ, D; PAGUIO, R; GREENWOOD, A.L; TAKAGI, M.

2003-09-01

OAK-B135 New high gain designs for direct drive ignition on NIF require foam shells. Scaled down versions of these designs are needed for near term experiments on the OMEGA laser facility at the Laboratory Laser Energetics (LLE). These shells need to be about 1 mm in diameter and 50-100 (micro)m wall thickness and densities of 100-250 mg/cc. In addition, a full density permeation seal needs to be deposited for retention of the fill gas at room temperature or the ice at cryogenic temperatures. They have fabricated such shells using Resorcinol-formaldehyde (R/F) as the selected foam material due to its transparency in the optical region. Extensive characterization of the wall uniformity of these shells has been performed. The foam shells have ∼ 5%-6% non-concentricities on the average. A full density permeation seal has been deposited on the R/F shells using two different techniques. In the first technique R/F shells are coated directly with plasma polymer to thicknesses of 3-4 (micro)m. In the second technique, R/F shells are coated with polyvinylphenol, using a chemical interfacial polymerization technique. Data on surface finish and gas retention for R/F shells coated by both methods are provided

Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 3

International Nuclear Information System (INIS)

Gwaltney, R.C.; Bolt, S.E.; Corum, J.M.; Bryson, J.W.

1975-06-01

The third in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: the experimental data provide design information directly applicable to nozzles in cylindrical vessels; and the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 3 had a 10 in. OD and the nozzle had a 1.29 in. OD, giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios for the cylinder and the nozzle were 50 and 7.68 respectively. Thirteen separate loading cases were analyzed. In each, one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for all the loadings were obtained using 158 three-gage strain rosettes located on the inner and outer surfaces. The loading cases were also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)

Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 4

International Nuclear Information System (INIS)

Gwaltney, R.C.; Bolt, S.E.; Bryson, J.W.

1975-06-01

The last in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models in the series are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: (1) the experimental data provide design information directly applicable to nozzles in cylindrical vessels, and (2) the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 4 had an outside diameter of 10 in., and the nozzle had an outside diameter of 1.29 in., giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios were 50 and 20.2 for the cylinder and nozzle respectively. Thirteen separate loading cases were analyzed. For each loading condition one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for each of the 13 loadings were obtained using 157 three-gage strain rosettes located on the inner and outer surfaces. Each of the 13 loading cases was also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)

Research on neutron energy spectrum of the beryllium, iron and polyethylene shells assemblies injected by D-T neutron

International Nuclear Information System (INIS)

An, Li; Guo, Haiping; Wang, Xinhua

2009-04-01

To test a simulation code, the multi-shell assemblies were established, which were made of beryllium stainless steel and polyethylene from the interior to the outer. The symmetry axes are all in the line of the D + beam. The neutron energy spectra above 1 MeV were obtained in medium by the detector of stilbene crystal of φ18 min x 20 mm. The distance between source and the spherical surface was 30 cm and 50 cm. The measurement channels are in the angle 0 degree and 120 degree relative to D + beam direction. The measurement positions are 0 cm, 9.7 cm, 12.8 cm and 17.3 cm away from the center of the assembly in both directions. The spectrum in different positions of the multi-shell assemblies in medium were compared and analyzed. (authors)

Performance of the RASNIK Optical Alignment Monitoring System for the LHCb Outer Tracker Detector

CERN Document Server

Szczekowski, Marek; Ukleja, Artur; Pellegrino, Antonio; Hart, Robert; Syryczynski, Krzysztof

2017-01-01

We present the results collected by an optical system for position control of the Outer Tracker detector stations in the LHCb experiment. This system has been constructed using the RASNIK three-point alignment monitors. The measurements are based on data taken in Run 2 of LHC.

Form and formation of flares and parabolae based on new observations of the internal shell structure in lytoceratid and perisphinctid ammonoids

Directory of Open Access Journals (Sweden)

Gregor Radtke

2016-08-01

Full Text Available The ultrastructure of pristine shells of Jurassic and Cretaceous lytoceratid and perisphinctid ammonoids indicates that flares and parabolae represent homologous structures. Both mark an interruption of shell growth. We dismiss earlier interpretations of parabolae as actual aperture, relics of resorbed apophyses or superstructure of the musculature associated to a semi-internal shell. Instead we propose an episodic growth model including several growth stops at the aperture during the formation of a frill-like aperture for parabolae and flares. Such an aperture is composed of the outer prismatic layer, the nacreous layer and an apertural prismatic coating. Here, we observed the apertural prismatic coating for the first time as an integral part of flares and parabolae. The apertural prismatic coating covers only the inner surface of the frill and was secreted by a permanent mantle cover indicating a prolonged period without the production of new shell material. Parabolae differ from flares by their general shape and the presence of ventro-lateral parabolic notches and nodes. The notches were formed by folding of the frill and had the potential to form semi-open spines. The corresponding parabolic nodes are caused by an outward swelling of the shell-secreting mantle tissue producing new shell material at the position of the folding. New shell material that belongs to the conch tube is attached to the base of flares and parabolae after withdrawal of the mantle edge representing the continuation of shell growth. Usually, the frilled aperture associated with flares and parabolae were removed during lifetime. This study reports on flares in Argonauticeras for the first time. In this genus they are typically associated with varices.

General Corrosion and Localized Corrosion of Waste Package Outer Barrier

Energy Technology Data Exchange (ETDEWEB)

K.G. Mon

2004-10-01

The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

Multibody dynamic analysis using a rotation-free shell element with corotational frame

Science.gov (United States)

Shi, Jiabei; Liu, Zhuyong; Hong, Jiazhen

2018-03-01

Rotation-free shell formulation is a simple and effective method to model a shell with large deformation. Moreover, it can be compatible with the existing theories of finite element method. However, a rotation-free shell is seldom employed in multibody systems. Using a derivative of rigid body motion, an efficient nonlinear shell model is proposed based on the rotation-free shell element and corotational frame. The bending and membrane strains of the shell have been simplified by isolating deformational displacements from the detailed description of rigid body motion. The consistent stiffness matrix can be obtained easily in this form of shell model. To model the multibody system consisting of the presented shells, joint kinematic constraints including translational and rotational constraints are deduced in the context of geometric nonlinear rotation-free element. A simple node-to-surface contact discretization and penalty method are adopted for contacts between shells. A series of analyses for multibody system dynamics are presented to validate the proposed formulation. Furthermore, the deployment of a large scaled solar array is presented to verify the comprehensive performance of the nonlinear shell model.

Ion microprobe assessment of the heterogeneity of Mg/Ca, Sr/Ca and Mn/Ca ratios in Pecten maximus and Mytilus edulis (bivalvia shell calcite precipitated at constant temperature

Directory of Open Access Journals (Sweden)

P. S. Freitas

2009-07-01

Full Text Available Small-scale heterogeneity of biogenic carbonate elemental composition can be a significant source of error in the accurate use of element/Ca ratios as geochemical proxies. In this study ion microprobe (SIMS profiles showed significant small-scale variability of Mg/Ca, Sr/Ca and Mn/Ca ratios in new shell calcite of the marine bivalves Pecten maximus and Mytilus edulis that was precipitated during a constant-temperature culturing experiment. Elevated Mg/Ca, Sr/Ca and Mn/Ca ratios were found to be associated with the deposition of elaborate shell features, i.e. a shell surface stria in P. maximus and surface shell disturbance marks in both species, the latter a common occurrence in bivalve shells. In both species the observed small-scale elemental heterogeneity most likely was not controlled by variable transport of ions to the extra-pallial fluid, but by factors such as the influence of shell organic content and/or crystal size and orientation, the latter reflecting conditions at the shell crystal-solution interface. In the mid and innermost regions of the P. maximus shell the lack of significant small-scale variation of Mg/Ca ratios, which is consistent with growth at constant temperature, suggest a potential application as a palaeotemperature proxy. Cross-growth band element/Ca ratio profiles in the interior of bivalve shells may provide more promising palaeo-environmental tools than sampling from the outer region of bivalve shells.

Isogeometric shell formulation based on a classical shell model

KAUST Repository

Niemi, Antti

2012-09-04

This paper constitutes the first steps in our work concerning isogeometric shell analysis. An isogeometric shell model of the Reissner-Mindlin type is introduced and a study of its accuracy in the classical pinched cylinder benchmark problem presented. In contrast to earlier works [1,2,3,4], the formulation is based on a shell model where the displacement, strain and stress fields are defined in terms of a curvilinear coordinate system arising from the NURBS description of the shell middle surface. The isogeometric shell formulation is implemented using the PetIGA and igakit software packages developed by the authors. The igakit package is a Python package used to generate NURBS representations of geometries that can be utilised by the PetIGA finite element framework. The latter utilises data structures and routines of the portable, extensible toolkit for scientific computation (PETSc), [5,6]. The current shell implementation is valid for static, linear problems only, but the software package is well suited for future extensions to geometrically and materially nonlinear regime as well as to dynamic problems. The accuracy of the approach in the pinched cylinder benchmark problem and present comparisons against the h-version of the finite element method with bilinear elements. Quadratic, cubic and quartic NURBS discretizations are compared against the isoparametric bilinear discretization introduced in [7]. The results show that the quadratic and cubic NURBS approximations exhibit notably slower convergence under uniform mesh refinement as the thickness decreases but the quartic approximation converges relatively quickly within the standard variational framework. The authors future work is concerned with building an isogeometric finite element method for modelling nonlinear structural response of thin-walled shells undergoing large rigid-body motions. The aim is to use the model in a aeroelastic framework for the simulation of flapping wings.

Facile synthesis of Ag@CeO{sub 2} core–shell plasmonic photocatalysts with enhanced visible-light photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Wu, Linen; Fang, Siman [State Key Laboratory of Heavy Oil Processing, College of Science, China University of Petroleum Beijing, No. 18 Fuxue Rd., Beijing 102249 (China); Department of Materials Science and Engineering, College of Science, China University of Petroleum Beijing, No. 18 Fuxue Rd., Beijing 102249 (China); Ge, Lei, E-mail: gelei08@sina.com [State Key Laboratory of Heavy Oil Processing, College of Science, China University of Petroleum Beijing, No. 18 Fuxue Rd., Beijing 102249 (China); Department of Materials Science and Engineering, College of Science, China University of Petroleum Beijing, No. 18 Fuxue Rd., Beijing 102249 (China); Han, Changcun; Qiu, Ping; Xin, Yongji [Department of Materials Science and Engineering, College of Science, China University of Petroleum Beijing, No. 18 Fuxue Rd., Beijing 102249 (China)

2015-12-30

Highlights: • Novel Ag@CeO{sub 2} core–shell nanostructures with well-controlled shape and shell thickness were successfully synthesized. • The Ag@CeO{sub 2} showed dramatic photocatalytic activity than pure CeO{sub 2}. • Improving activity is from a combination of SPR effect and hybrid effects. • The mechanism was proposed and confirmed by ESR and PL results. - Abstract: Novel Ag@CeO{sub 2} core–shell nanostructures with well-controlled shape and shell thickness were successfully synthesized via a green and facile template-free approach in aqueous solution. As-prepared samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflection spectroscopy (DRS), electron spin resonance (ESR) and photoluminescence spectroscopy (PL). The structures with different core shapes and controllable shell thickness exhibited unique optical properties. It is found that the nanoscale Ag@CeO{sub 2} core–shell photocatalysts exhibit significantly enhanced photocatalytic activities in the O{sub 2} evolution and MB dye degradation compared to pure CeO{sub 2} nanoparticals. The enhancement in photocatalytic activities can be ascribed to the localized surface plasmon resonance (SPR) of Ag cores. Moreover, larger active interfacial areas and contact between metal/semiconductor in the core–shell structure facilitate transfer of charge carriers and prolong lifetime of photogenerated electron-hole pairs. It is expected that the Ag@CeO{sub 2} core–shell structure may have great potential in a wider range of light-harvesting applications.

Periplasmic quality control in biogenesis of outer membrane proteins.

Science.gov (United States)

Lyu, Zhi Xin; Zhao, Xin Sheng

2015-04-01

The β-barrel outer membrane proteins (OMPs) are integral membrane proteins that reside in the outer membrane of Gram-negative bacteria and perform a diverse range of biological functions. Synthesized in the cytoplasm, OMPs must be transported across the inner membrane and through the periplasmic space before they are assembled in the outer membrane. In Escherichia coli, Skp, SurA and DegP are the most prominent factors identified to guide OMPs across the periplasm and to play the role of quality control. Although extensive genetic and biochemical analyses have revealed many basic functions of these periplasmic proteins, the mechanism of their collaboration in assisting the folding and insertion of OMPs is much less understood. Recently, biophysical approaches have shed light on the identification of the intricate network. In the present review, we summarize recent advances in the characterization of these key factors, with a special emphasis on the multifunctional protein DegP. In addition, we present our proposed model on the periplasmic quality control in biogenesis of OMPs.

Temperature Field Accurate Modeling and Cooling Performance Evaluation of Direct-Drive Outer-Rotor Air-Cooling In-Wheel Motor

Directory of Open Access Journals (Sweden)

Feng Chai

2016-10-01

Full Text Available High power density outer-rotor motors commonly use water or oil cooling. A reasonable thermal design for outer-rotor air-cooling motors can effectively enhance the power density without the fluid circulating device. Research on the heat dissipation mechanism of an outer-rotor air-cooling motor can provide guidelines for the selection of the suitable cooling mode and the design of the cooling structure. This study investigates the temperature field of the motor through computational fluid dynamics (CFD and presents a method to overcome the difficulties in building an accurate temperature field model. The proposed method mainly includes two aspects: a new method for calculating the equivalent thermal conductivity (ETC of the air-gap in the laminar state and an equivalent treatment to the thermal circuit that comprises a hub, shaft, and bearings. Using an outer-rotor air-cooling in-wheel motor as an example, the temperature field of this motor is calculated numerically using the proposed method; the results are experimentally verified. The heat transfer rate (HTR of each cooling path is obtained using the numerical results and analytic formulas. The influences of the structural parameters on temperature increases and the HTR of each cooling path are analyzed. Thereafter, the overload capability of the motor is analyzed in various overload conditions.

Synthesis of NiO-TiO2 hybrids/mSiO2 yolk-shell architectures embedded with ultrasmall gold nanoparticles for enhanced reactivity

Science.gov (United States)

Fang, Jiasheng; Zhang, Yiwei; Zhou, Yuming; Zhao, Shuo; Zhang, Chao; Huang, Mengqiu; Gao, Yan

2017-08-01

Novel NiO-TiO2 hybrids/mSiO2 yolk-shell architectures loaded with ultrasmall Au nanoparticles (STNVS-Au) were developed via the rational synthetic strategy. The hierarchical yolk-shell nanostructures (STNVS) with high surface areas were constructed by a facile "bottom-up" assembly process using SiO2 materials and polymer resins as cores/shells and sacrificial templates, accompanied by a simple hydrothermal incorporation of NiO into uniform amorphous TiO2 layers that were converted to NiO-anatase TiO2 p-n heterojunction hybrids. Then, numerous sub-3 nm Au nanoparticles were post encapsulated within STNVS nanostructures through the low-temperature hydrogen reduction based on the unique deposition-precipitation method with Au(en)2Cl3 compounds as gold precursors. The NiO-TiO2 hybrids alloying with Au nanoparticles were effectively protected and entrapped within STNVS architectures, and interacted with outer mSiO2-Au shells, which comprised the powerful STNVS-Au yolk-shell nanoreactors and produced stronger configural synergies in enhancing the heterogeneous catalysis. Into catalyzing the reduction of 4-nitrophenol to 4-aminophenol, the STNVS-Au was shown with outstanding activity and reusability, and its pristine morphology was well retained during the recycling process.

Experiment on vibration in water of a cylindrical shell fixed in water; Suichu ni koteisareta ento shell no sessui shindo jikken

Energy Technology Data Exchange (ETDEWEB)

Toyota, K; Yasuzawa, Y; Kagawa, K; Nanatsuya, Y [Kyushu University, Fukuoka (Japan). Faculty of Engineering

1996-04-10

In order to utilize more effectively wide oceanic spaces, a feasibility study is performed on submerged large shell structures from the aspect of structural engineerings. As part of the study, for the purpose of deriving dynamic response characteristics of a structure, development was made on a numerical analysis code, `DASOR`, required to analyze natural frequency of a rotating shell fixed in water. The `DASOR` is a dynamic analysis code to derive added water mass effect, and effects of water depth on the dynamic response characteristics based on the shell theory by Donnell-Mushtari-Vlasov. This paper describes an experiment using a cylindrical shell to elucidate effects of the cylindrical shell on vibration characteristics due to contact with water. Comparisons and discussions were given on the result of numerical calculation using the `DASOR`, solution of a simplified theory analysis, and the result of the experiment to make clear the reasonability of the `DASOR`. The cylindrical shell in water has its natural frequency decreased due to the added water mass effect in association with increase in the water level. The `DASOR` showed good agreement with the experimental values as a result of giving considerations on the boundary conditions, by which its reasonability was verified. 3 refs., 9 figs., 2 tabs.

Design of 8-ft-Diameter Barrel Test Article Attachment Rings for Shell Buckling Knockdown Factor Project

Science.gov (United States)

Lovejoy, Andrew E.; Hilburger, Mark W.

2010-01-01

The Shell Buckling Knockdown Factor (SBKF) project includes the testing of sub-scale cylinders to validate new shell buckling knockdown factors for use in the design of the Ares-I and Ares-V launch vehicles. Test article cylinders represent various barrel segments of the Ares-I and Ares-V vehicles, and also include checkout test articles. Testing will be conducted at Marshall Space Flight Center (MSFC) for test articles having an eight-foot diameter outer mold line (OML) and having lengths that range from three to ten feet long. Both ends of the test articles will be connected to the test apparatus using attachment rings. Three multiple-piece and one single-piece design for the attachment rings were developed and analyzed. The single-piece design was chosen and will be fabricated from either steel or aluminum (Al) depending on the required safety factors (SF) for test hardware. This report summarizes the design and analysis of these attachment ring concepts.

Multi-functional carbon microspheres with double shell layers for flame retardant poly (ethylene terephthalate)

Science.gov (United States)

Xue, Baoxia; Niu, Mei; Yang, Yongzhen; Bai, Jie; Song, Yinghao; Peng, Yun; Liu, Xuguang

2018-03-01

Carbon microspheres (CMSs) as a core material had been coated by two capsule walls: an inorganic material of magnesium hydroxide (MH) as inner shell layer and an organic material of poly (ethylene terephthalate) (PET) as outer shell layer. MH coating CMSs (MCMSs) were fabricated by liquid phase deposition method, then grafted 3-Aminopropyltriethoxysilane (APTS) to obtain the Si-MCMSs. Microencapsulated Si-MCMSs (PMCMSs) was prepared by in situ polymerization method. Morphology structure, dispersion, flame retardant and other properties of PMCMSs have been investigated. A series of PET blends were prepared by melt compounding. The results showed that MH and PET as two layers were coated on CMSs surface with the optimal thickness of about 70 nm. The PMCMSs owned better dispersion in PET matrix. Compared with MCMSs/PET composites, the mechanical property of PMCMSs/PET composites had significantly increased because of the strong interface binding force between PMCMSs and PET matrix. Moreover, PMCMSs was proved to be an effective flame retardant. For PMCMSs/PET with 2 wt% PMCMSs, the limiting oxygen index (LOI) value increased from 21.0% (pristine PET) to 27.2%, and the peak heat release rate (pk-HRR) decreased from 513.22 kW/m2 to 352.14 kW/m2. The decreased smoke production rate (SPR) and total smoke production (TSP) values demonstrated PMCMSs suppressed the smoke production. The increased Fire performance index (FPI) value illustrated PMCMSs significantly reduced the fire risk of PET. Overall, the two capsular walls endowed the PMCMSs/PET composites with good mechanical and flame-retardant properties.

Enhanced linear photonic nanojet generated by core-shell optical microfibers

Science.gov (United States)

Liu, Cheng-Yang; Yen, Tzu-Ping; Chen, Chien-Wen

2017-05-01

The generation of linear photonic nanojet using core-shell optical microfiber is demonstrated numerically and experimentally in the visible light region. The power flow patterns for the core-shell optical microfiber are calculated by using the finite-difference time-domain method. The focusing properties of linear photonic nanojet are evaluated in terms of length and width along propagation and transversal directions. In experiment, the silica optical fiber is etched chemically down to 6 μm diameter and coated with metallic thin film by using glancing angle deposition. We show that the linear photonic nanojet is enhanced clearly by metallic shell due to surface plasmon polaritons. The large-area superresolution imaging can be performed by using a core-shell optical microfiber in the far-field system. The potential applications of this core-shell optical microfiber include micro-fluidics and nano-structure measurements.

Small RNAs controlling outer membrane porins

DEFF Research Database (Denmark)

Valentin-Hansen, Poul; Johansen, Jesper; Rasmussen, Anders A

2007-01-01

are key regulators of environmental stress. Recent work has revealed an intimate interplay between small RNA regulation of outer membrane proteins and the stress-induced sigmaE-signalling system, which has an essential role in the maintenance of the integrity of the outer membrane.......Gene regulation by small non-coding RNAs has been recognized as an important post-transcriptional regulatory mechanism for several years. In Gram-negative bacteria such as Escherichia coli and Salmonella, these RNAs control stress response and translation of outer membrane proteins and therefore...

Shell closure in stable and unstable Fermion systems

International Nuclear Information System (INIS)

Lombard, R.J.

1991-01-01

Some of the findings of calculations performed with the density functional method in connection with shell closure are presented. In nuclei, some evidences seam to confirm the existence of a shell closure at N or Z=16, for Z or N<11. More data, particularly spectroscopic measurements would provide further information. Single particle energies for Z=16 isotopes as function of the neutron number N are given. (G.P.) 9 refs.; 6 figs

Folic acid-functionalized magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell composite particles: synthesis and application in drug release.

Science.gov (United States)

Yang, Dandan; Wei, Kaiwei; Liu, Qi; Yang, Yong; Guo, Xue; Rong, Hongren; Cheng, Mei-Ling; Wang, Guoxiu

2013-07-01

A drug delivery system was designed by deliberately combining the useful functions into one entity, which was composed of magnetic ZnFe2O4 hollow microsphere as the core, and mesoporous silica with folic acid molecules as the outer shell. Amine groups coated magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell (MZHM-MSS-NH2) composite particles were first synthesized by a one-pot direct co-condensation method. Subsequently a novel kind of folic acid-functionalized magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell (MZHM-MSS-NHFA) composite particles were synthesized by conjugating folic acid as targeted molecule to MZHM-MSS-NH2. Ibuprofen, a well-known antiphlogistic drug, was used as a model drug to assess the loading and releasing behavior of the composite microspheres. The results show that the MZHM-MSS-NHFA system has the higher capacity of drug storage and good sustained drug-release property. Copyright © 2013 Elsevier B.V. All rights reserved.

The role of multiple ionization and subshell coupling effects in L-shell ionization of Au by oxygen ions

International Nuclear Information System (INIS)

Banas, D.; Braziewicz, J.; Pajek, M.; Semaniak, J.; Czyzewski, T.; Fijal, I.; Jaskola, M.; Kretschmer, W.; Mukoyama, T.; Trautmann, D.

2002-01-01

The ionization of L-subshell electrons in gold by the impact of 0.4-2.2 MeV amu -1 O ions was studied by observing excited Lγ(L-N, O) x-rays. We demonstrate that both the multiple ionization in outer M- and N-shells as well as the coupling effects in the L-shell play an important role in understanding the measured L-subshell ionization cross sections. The multiple ionization was found to be important in two aspects: first, the analysis of x-ray energy shifts and line broadening was crucial for proper interpretation of measured x-ray spectra; second, the additional vacancies in the M- and N-shells substantially influenced the L 1 -subshell fluorescence and Coster-Kronig (CK) yields, mainly by closing strong L 1 -L 3 M 4,5 CK transitions. The data are compared with the simplified coupled-channels calculations using the 'coupled-subshell model' (CSM) based on the semiclassical approximation (SCA), which describes both direct Coulomb ionization as well as the L-subshell couplings within the same theoretical approach. A good agreement of the present data with the theoretical predictions based on the discussed SCA-CSM approach is observed. Present findings partly explain the long-standing problem of inadequate theoretical description of L-shell ionization by heavy ion impact. (author)

Effect of Steel Framing for Securing Drywall Panels on Thermal and Humidity Parameters of the Outer Walls

Science.gov (United States)

Major, Maciej; Kosiń, Mariusz

2017-12-01

The paper analyses the effect of steel framing used to secure drywall panels on thermal and humidity properties of outer walls. In the practice of building a light structure, the most popular components are steel and wood studs. They are used to obtain framing for building a wall (an outer wall in this study). Analysis presented in this study concerned the corner of the outer wall build using the technology of light steel framing. Computer simulation was used to perform thermal and humidity analysis for the joint of the outer wall.

Effect of Steel Framing for Securing Drywall Panels on Thermal and Humidity Parameters of the Outer Walls

Directory of Open Access Journals (Sweden)

Major Maciej

2017-12-01

Full Text Available The paper analyses the effect of steel framing used to secure drywall panels on thermal and humidity properties of outer walls. In the practice of building a light structure, the most popular components are steel and wood studs. They are used to obtain framing for building a wall (an outer wall in this study. Analysis presented in this study concerned the corner of the outer wall build using the technology of light steel framing. Computer simulation was used to perform thermal and humidity analysis for the joint of the outer wall.

Facile and controllable construction of vanadium pentoxide@conducting polymer core/shell nanostructures and their thickness-dependent synergistic energy storage properties

International Nuclear Information System (INIS)

Tong, Zhongqiu; Liu, Shikun; Li, Xingang; Ding, Yanbo; Zhao, Jiupeng; Li, Yao

2016-01-01

Graphical abstract: Here, we report a novel approach to prepare metal oxide@conducting polymer core/shell hybrids with controlled shell thickness and morphology, and the influence of PANI shell thickness on the electrochemical performance of V 2 O 5 @PANI core/shell hybrids is systematically investigated. Thickness-dependent synergistic electron transport, Li-ion diffusion distance, and shell mechanical strength mechanisms are proposed. - Highlights: • Thickness- and morphology-controlled V 2 O 5 /PANI core/shell hybrid nanofibers are fabricated. • The enhancement of energy storage performance of core/shell hybrids varies with the shell thickness. • Thickness-dependent synergistic electron transport, Li-ion diffusion distances, and shell mechanical strength mechanisms are proposed. - Abstract: Thickness- and morphology-controlled vanadium pentoxide/polyaniline (V 2 O 5 /PANI) core/shell hybrid nanofibers are fabricated by electropolymerization of PANI on V 2 O 5 nanofibers for enhanced energy storage. By simply adjusting the electrodeposition time, the thickness of the PANI shells can be controlled from 5 nm to 47 nm, and the morphology can be changed from coaxial to branched. The influence of shell thickness on the improved Li-ion storage performance of the V 2 O 5 /PANI core/shell nanofibers is systematically investigated, and this enhancement of charge capability and cycling stability strongly varies with the shell thickness. Thickness-dependent synergistic electron transport, Li-ion diffusion distances, and shell mechanical strength mechanisms are also proposed. These results provide meaningful references for developing new functional core/shell materials and high-performance energy storage composite materials.

Synthesis of Ni core NiO shell nanostructure and magnetic investigation for shell thickness determination

International Nuclear Information System (INIS)

Arabi, H.; Bruck, E.; Tichelaar, F.D.

2007-01-01

Full text: Nickel oxide has received a considerable amount of attention in recent years for its catalytic, electronic and magnetic properties. Ni nanoparticles with an average size of 8 nm were prepared by dc - arc discharge in argon atmosphere. A current of 130 A and 300 milli bar pressure of argon have been applied. The produced Ni nanoparticles were annealed for oxidizing in air at 350 for six hours to produce antiferromagnetic NiO particles. The structure of Ni and NiO nanoparticles and size estimation of them studied by means of X-ray diffraction. The size and morphology of the particles were also characterized by high resolution transmission microscopy (TEM). The Ni core NiO shell structure, resulting from the oxidation process, were studied by magnetic properties measurements. A quantum design squid magnetometer, model MPMS5S was used for measuring saturation magnetization of both nanoparticles of Ni with and without NiO layer. By knowing the density of Ni and NiO, we were able to deduce the thickness of the Ni core and NiO outer layer. They are around 3 and 5 nanometers respectively. (authors)

Multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution as a mechanism to generate intermediate band energy levels

Science.gov (United States)

Rodríguez-Magdaleno, K. A.; Pérez-Álvarez, R.; Martínez-Orozco, J. C.; Pernas-Salomón, R.

2017-04-01

In this work the generation of an intermediate band of energy levels from multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution is reported. Within the effective mass approximation the electronic structure of a GaAs spherical quantum-dot surrounded by one, two and three shells is studied in detail using a numerically stable transfer matrix method. We found that a shells-size distribution characterized by continuously wider GaAs domains is a suitable mechanism to generate the intermediate band whose width is also dependent on the Aluminium concentration x. Our results suggest that this effective mechanism can be used for the design of wider intermediate band than reported in other quantum systems with possible solar cells enhanced performance.

Mitochondrial dysfunction underlying outer retinal diseases

DEFF Research Database (Denmark)

Lefevere, Evy; Toft-Kehler, Anne Katrine; Vohra, Rupali

2017-01-01

Dysfunction of photoreceptors, retinal pigment epithelium (RPE) or both contribute to the initiation and progression of several outer retinal disorders. Disrupted Müller glia function might additionally subsidize to these diseases. Mitochondrial malfunctioning is importantly associated with outer...

Molluscan shell colour.

Science.gov (United States)

Williams, Suzanne T

2017-05-01

The phylum Mollusca is highly speciose, and is the largest phylum in the marine realm. The great majority of molluscs are shelled, including nearly all bivalves, most gastropods and some cephalopods. The fabulous and diverse colours and patterns of molluscan shells are widely recognised and have been appreciated for hundreds of years by collectors and scientists alike. They serve taxonomists as characters that can be used to recognise and distinguish species, however their function for the animal is sometimes less clear and has been the focus of many ecological and evolutionary studies. Despite these studies, almost nothing is known about the evolution of colour in molluscan shells. This review summarises for the first time major findings of disparate studies relevant to the evolution of shell colour in Mollusca and discusses the importance of colour, including the effects of visual and non-visual selection, diet and abiotic factors. I also summarise the evidence for the heritability of shell colour in some taxa and recent efforts to understand the molecular mechanisms underpinning synthesis of shell colours. I describe some of the main shell pigments found in Mollusca (carotenoids, melanin and tetrapyrroles, including porphyrins and bile pigments), and their durability in the fossil record. Finally I suggest that pigments appear to be distributed in a phylogenetically relevant manner and that the synthesis of colour is likely to be energetically costly. © 2016 Cambridge Philosophical Society.

Immediate catalytic upgrading of soybean shell bio-oil

International Nuclear Information System (INIS)

Bertero, Melisa; Sedran, Ulises

2016-01-01

The pyrolysis of soybean shell and the immediate catalytic upgrading of the bio-oil over an equilibrium FCC catalyst was studied in order to define its potential as a source for fuels and chemicals. The experiments of pyrolysis and immediate catalytic upgrading were performed at 550 °C during 7 min with different catalysts to oil relationships in an integrated fixed bed pyrolysis-conversion reactor. The results were compared under the same conditions against those from pine sawdust, which is a biomass source commonly used for the production of bio-oil. In the pyrolysis the pine sawdust produced more liquids (61.4%wt.) than the soybean shell (54.7%wt.). When the catalyst was presented, the yield of hydrocarbons increased, particularly in the case of soybean shell, which was four time higher than in the pyrolysis. The bio-oil from soybean shell produced less coke (between 3.1 and 4.3%wt.) in its immediate catalytic upgrading than that from pine sawdust (between 5 and 5.8%wt.), due to its lower content of phenolic and other high molecular weight compounds (three and five times less, respectively). Moreover, soybean shell showed a higher selectivity to hydrocarbons in the gasoline range, with more olefins and less aromatic than pine sawdust. - Highlights: • Soybean shell is a possible source of fuels with benefits as compared to pine sawdust. • Bio-oils upgraded over FCC catalyst in an integrated pyrolysis-conversion reactor. • Pine sawdust bio-oil had more phenols than soybean shell bio-oil. • Soybean shell bio-oil produced more hydrocarbons in gasoline range and less coke.

Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity

Directory of Open Access Journals (Sweden)

Schilthuizen Menno

2003-06-01

Full Text Available Abstract Background Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not previously been explored. Presentation of the hypothesis The hypothesis that is presented consists of two parts. First, that shell ornamentation is the result of sexual selection. Second, that such sexual selection has caused the divergence in shell shape in different species. Testing the hypothesis The first part of the hypothesis may be tested by searching for sexual dimorphism in shell ornamentation in gonochoristic snails, by searching for increased variance in shell ornamentation relative to other shell traits, and by mate choice experiments using individuals with experimentally enhanced ornamentation. The second part of the hypothesis may be tested by comparing sister groups and correlating shell diversity with degree of polygamy. Implications of the hypothesis If the hypothesis were true, it would provide an explanation for the many cases of allopatric evolutionary radiation in snails, where shell diversity cannot be related to any niche differentiation or environmental differences.

Performance Evaluation of the Effect of waste paper on Groundnut Shell Briquette

Directory of Open Access Journals (Sweden)

Olatunde A Oyelaran

2015-07-01

Full Text Available Current energy shortage and environmental issues resulting from the use of fossil fuels have lead to exploitation of renewable energy resources that includes municipal waste and agricultural residues. These residues are available, indigenous and are environmental friendly but some can not be used directly in combustion process due high moisture content and low volumetric energy unless by briquetting. The study was undertaken to assess the combustion characteristic of binderless briquettes produced from waste paper and groundnut shell. Combustion characteristics investigated were ignition time, burning time, calorific values, burning rate, specific fuel consumption, fuel efficiency and water boiling time. The calorific values of the briquettes ranged from 19.51 - 19.92 MJ/kg, while the thermal efficiency ranges between 13.75 – 21.64%, other results shows that the average burning rate between 0.511 and 1.133 kg/hr and the specific fuel consumption ranges between 0.087 and 0.131 J/g. The recorded boiling time values were between 17.5 and 30.0 minutes for cold start and 15.0 and 20.0 minutes for hot start. The results shows that waste paper and groundnut shell up to 25% in composition composite briquettes were found to have good combustion characteristics which qualify them as alternative to firewood for domestic and industrial energy. However, production of briquettes from waste paper and groundnut shell at mixing ratio of 85:15 was found to comparatively better from all experiment conducted.

The geometry of on-shell diagrams

Science.gov (United States)

Franco, Sebastián; Galloni, Daniele; Mariotti, Alberto

2014-08-01

The fundamental role of on-shell diagrams in quantum field theory has been recently recognized. On-shell diagrams, or equivalently bipartite graphs, provide a natural bridge connecting gauge theory to powerful mathematical structures such as the Grassmannian. We perform a detailed investigation of the combinatorial and geometric objects associated to these graphs. We mainly focus on their relation to polytopes and toric geometry, the Grassmannian and its stratification. Our work extends the current understanding of these connections along several important fronts, most notably eliminating restrictions imposed by planarity, positivity, reducibility and edge removability. We illustrate our ideas with several explicit examples and introduce concrete methods that considerably simplify computations. We consider it highly likely that the structures unveiled in this article will arise in the on-shell study of scattering amplitudes beyond the planar limit. Our results can be conversely regarded as an expansion in the understanding of the Grassmannian in terms of bipartite graphs.

Collapsing shells and black holes: a quantum analysis

Science.gov (United States)

Leal, P.; Bernardini, A. E.; Bertolami, O.

2018-06-01

The quantization of a spherically symmetric null shells is performed and extended to the framework of phase-space noncommutative (NC) quantum mechanics. This shell is considered to be inside a black hole event horizon. The encountered properties are investigated making use of the Israel junction conditions on the shell, considering that it is the boundary between two spherically symmetric spacetimes. Using this method, and considering two different Kantowski–Sachs spacetimes as a representation for the Schwarzschild spacetime, the relevant quantities on the shell are computed, such as its stress-energy tensor and the action for the whole spacetime. From the obtained action, the Wheeler–deWitt equation is deduced in order to provide the quantum framework for the system. Solutions for the wave function of the system are found on both the commutative and NC scenarios. It is shown that, on the commutative version, the wave function has a purely oscillatory behavior in the interior of the shell. In the NC setting, it is shown that the wave function vanishes at the singularity, as well as, at the event horizon of the black hole.

Windows PowerShell 20 Bible

CERN Document Server

Lee, Thomas; Schill, Mark E; Tanasovski, Tome

2011-01-01

Here's the complete guide to Windows PowerShell 2.0 for administrators and developers Windows PowerShell is Microsoft's next-generation scripting and automation language. This comprehensive volume provides the background that IT administrators and developers need in order to start using PowerShell automation in exciting new ways. It explains what PowerShell is, how to use the language, and specific ways to apply PowerShell in various technologies. Windows PowerShell is Microsoft's standard automation tool and something that every Windows administrator will eventually have to understand; this b

Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

KAUST Repository

Fahad, Hossain M.; Smith, Casey; Rojas, Jhonathan Prieto; Hussain, Muhammad Mustafa

2011-01-01

We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow. © 2011 American Chemical Society.

Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

KAUST Repository

Fahad, Hossain M.

2011-10-12

We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow. © 2011 American Chemical Society.

Windows PowerShell desired state configuration revealed

CERN Document Server

Chaganti, Ravikanth

2014-01-01

Desired State Configuration (DSC) is a powerful new configuration management platform that makes it easier than ever to perform cross-platform configuration management of your infrastructure, whether on-premise or in the cloud. DSC provides the management platform and Application Programming Interface (API) that can be used with any programming language. Windows PowerShell Desired State Configuration Revealed will take you through this new technology from start to finish and demonstrates the DSC interfaces through Windows PowerShell. DSC allows you to manage target devices by simply declarin

Effects of Cocoa Bean Shell on the Performance, Blood Indices and ...

African Journals Online (AJOL)

isonitrogenous and isocaloric dietary treatments of 0%, 5% 10%, 15% and 20% Cocoa Bean Shell(CBS) in a complete randomized design experiments. Each dietary treatment was replicated three times for an experimental period of 18 weeks (3-8 weeks of age, starter diet, 9-20 weeks of age, grower diet). At the starter ...

Effects of alga polysaccharide capsule shells on in-vivo bioavailability and disintegration

Science.gov (United States)

Li, Ting; Guo, Shuju; Ma, Lin; Yuan, Yi; Han, Lijun

2012-01-01

Gelatin has been used in hard capsule shells for more than a century, and some shortcomings have appeared, such as high moisture content and risk of transmitting diseases of animal origin to people. Based on available studies regarding gelatin and vegetable shells, we developed a new type of algal polysaccharide capsule (APPC) shells. To test whether our products can replace commercial gelatin shells, we measured in-vivo plasma concentration of 12 selected volunteers with a model drug, ibuprofen, using high performance liquid chromatography (HPLC), by calculating the relative bioavailability of APPC and Qualicaps® referenced to gelatin capsules and assessing bioequivalence of the three types of shells, and calculated pharmacokinetic parameters with the software DAS 2.0 (China). The results show that APPC shells possess bioequivalence with Qualicaps® and gelatin shells. Moreover, the disintegration behavior of four types of shells (APPC, Vegcaps®, Qualicaps® and gelatin shells) with the content of lactose and radioactive element (99mTc) was observed via gamma-scintigraphic images. The bioavailability and gamma-scintigraphic studies showed that APPC was not statistically different from other vegetable and gelatin capsule shells with respect to in-vivo behavior. Hence, it can be concluded that APPCs are exchangeable with other vegetable and gelatin shells.

Performance and risk assessment of subsurface barriers for single-shell tank waste retrieval

Energy Technology Data Exchange (ETDEWEB)

Bazinet, G.D.; Cruse, J.M.; Hampsten, K.L. [Westinghouse Hanford Co., Richland, WA (United States); Treat, R.L.

1995-02-01

Subsurface barriers are among various alternatives under evaluation to mitigate the threat of leakage from the Hanford Site`s 149 single-shell high-level radioactive waste tanks. The Tank Waste Remediation System (TWRS) division of Westinghouse Hanford Company is conducting this evaluation of subsurface barriers and other alternatives, focusing on risk and cost as performance measures. A number of alternative retrieval/closure approaches were evaluated in terms of risks (carcinogenic and toxicological) to a postulated maximally exposed individual. In addition, worker and accident risks were evaluated and factors developed for each alternative on a relative basis. The work performed to date indicates the use of subsurface barriers may potentially reduce public risk by limiting contamination of groundwater below the Hanford Site; however, the cost in terms of actual funding and in elevated worker risk is significant. The analyses also assume certain performance levels for technologies that have not been demonstrated in field conditions similar to Hanford Site tank farms. The evaluations summarized herein are being used to support a decision by representatives of the US Department of Energy, Richland Operations Office, the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA) regarding potential further development of subsurface barrier technology.

Performance and risk assessment of subsurface barriers for single-shell tank waste retrieval

International Nuclear Information System (INIS)

Bazinet, G.D.; Cruse, J.M.; Hampsten, K.L.; Treat, R.L.

1995-02-01

Subsurface barriers are among various alternatives under evaluation to mitigate the threat of leakage from the Hanford Site's 149 single-shell high-level radioactive waste tanks. The Tank Waste Remediation System (TWRS) division of Westinghouse Hanford Company is conducting this evaluation of subsurface barriers and other alternatives, focusing on risk and cost as performance measures. A number of alternative retrieval/closure approaches were evaluated in terms of risks (carcinogenic and toxicological) to a postulated maximally exposed individual. In addition, worker and accident risks were evaluated and factors developed for each alternative on a relative basis. The work performed to date indicates the use of subsurface barriers may potentially reduce public risk by limiting contamination of groundwater below the Hanford Site; however, the cost in terms of actual funding and in elevated worker risk is significant. The analyses also assume certain performance levels for technologies that have not been demonstrated in field conditions similar to Hanford Site tank farms. The evaluations summarized herein are being used to support a decision by representatives of the US Department of Energy, Richland Operations Office, the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA) regarding potential further development of subsurface barrier technology

Determination of K shell absorption jump factors and jump ratios of 3d transition metals by measuring K shell fluorescence parameters

International Nuclear Information System (INIS)

Kaçal, Mustafa Recep; Han, İbrahim; Akman, Ferdi

2015-01-01

Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring K-shell absorption jump factors and jump ratios for Ti, Cr, Fe, Co, Ni and Cu elements. The jump factors and jump ratios for these elements were determined by measuring K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation and transmission experimental geometry. The measured values for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature. - Highlights: • This work regard the K shell absorption jump ratios and jump factors of Ti, Cr, Fe, Co, Ni and Cu. • This paper presents the first measurement of these parameters using the experimental K shell fluorescence parameters. • A good agreement was found between experimental and theoretical values. • The EDXRF technique was suitable, precise and reliable for the measurement of these atomic parameters

[Adsorption of Cu on Core-shell Structured Magnetic Particles: Relationship Between Adsorption Performance and Surface Properties].

Science.gov (United States)

Li, Qiu-mei; Chen, Jing; Li, Hai-ning; Zhang, Xiao-lei; Zhang, Gao-sheng

2015-12-01

In order to reveal the relationship between the adsorption performance of adsorbents and their compositions, structure, and surface properties, the core-shell structured Fe₃O₄/MnO2 and Fe-Mn/Mn₂2 magnetic particles were systematically characterized using multiple techniques and their Cu adsorption behaviors as well as mechanism were also investigated in details. It was found that both Fe₃O4 and Fe-Mn had spinel structure and no obvious crystalline phase change was observed after coating with MnO₂. The introduction of Mn might improve the affinity between the core and the shell, and therefore enhanced the amount and distribution uniformity of the MnO₂ coated. Consequently, Fe-Mn/MnO₂ exhibited a higher BET specific surface area and a lower isoelectric point. The results of sorption experiments showed that Fe-Mn had a higher maximal Cu adsorption capacity of 33.7 mg · g⁻¹ at pH 5.5, compared with 17.5 mg · g⁻¹ of Fe₃O4. After coating, the maximal adsorption capacity of Fe-Mn/MnO₂ was increased to 58.2 mg · g⁻¹, which was 2.6 times as high as that of Fe₃O₄/MnO₂ and outperformed the majority of magnetic adsorbents reported in literature. In addition, a specific adsorption of Cu occurred at the surface of Fe₃O₄/MnO₂ or Fe-Mn/MnO₂ through the formation of inner-sphere complexes. In conclusion, the adsorption performance of the magnetic particles was positively related to their compositions, structure, and surface properties.

AUTOMATED BATCH CHARACTERIZATION OF ICF SHELLS WITH VISION-ENABLED OPTICAL MICROSCOPE SYSTEM

International Nuclear Information System (INIS)

HUANG, H.; STEPHENS, R.B.; HILL, D.W.; LYON, C.; NIKROO, A.; STEINMAN, D.A.

2003-09-01

OAK-B135 Inertial Confinement Fusion (ICF) shells are mesoscale objects with nano-scale dimensional and nano-surface finish requirements. Currently, the shell dimensions are measured by white-light interferometry and an image analysis method. These two methods complement each other and give a rather complete data set on a single shell. The process is, however, labor intensive. They have developed an automation routine to fully characterize a shell in one shot and perform unattended batch measurements. The method is useful to the ICF program both for production screening and for full characterization. It also has potential for Inertial Fusion Energy (IFE) power plant where half a million shells need to be processed daily

The CMS Outer Hadron Calorimeter

CERN Document Server

Acharya, Bannaje Sripathi; Banerjee, Sunanda; Banerjee, Sudeshna; Bawa, Harinder Singh; Beri, Suman Bala; Bhandari, Virender; Bhatnagar, Vipin; Chendvankar, Sanjay; Deshpande, Pandurang Vishnu; Dugad, Shashikant; Ganguli, Som N; Guchait, Monoranjan; Gurtu, Atul; Kalmani, Suresh Devendrappa; Kaur, Manjit; Kohli, Jatinder Mohan; Krishnaswamy, Marthi Ramaswamy; Kumar, Arun; Maity, Manas; Majumder, Gobinda; Mazumdar, Kajari; Mondal, Naba Kumar; Nagaraj, P; Narasimham, Vemuri Syamala; Patil, Mandakini Ravindra; Reddy, L V; Satyanarayana, B; Sharma, Seema; Singh, B; Singh, Jas Bir; Sudhakar, Katta; Tonwar, Suresh C; Verma, Piyush

2006-01-01

The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with a outer calorimeter to ensure high energy shower containment in CMS and thus working as a tail catcher. Fabrication, testing and calibrations of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing $\\et$ measurements at LHC energies. The outer hadron calorimeter has a very good signal to background ratio even for a minimum ionising particle and can hence be used in coincidence with the Resistive Plate Chambers of the CMS detector for the muon trigger.

Determination of Core-Shell Structures in Pd-Hg Nanoparticles by STEM-EDX

DEFF Research Database (Denmark)

Deiana, Davide; Verdaguer Casadevall, Arnau; Malacrida, Paolo

2015-01-01

The structural and elemental configuration of a high-performing Pd-Hg electrocatalyst for oxygen reduction to hydrogen peroxide has been studied by means of high-resolution scanning transmission electron microscopy. Pd-Hg nanoparticles are shown to have a crystalline core-shell structure, with a Pd...... core and a Pd-Hg ordered alloy shell. The ordered shell is responsible for the high oxygen reduction selectivity to H2O2....

Interface bond relaxation on the thermal conductivity of Si/Ge core-shell nanowires

Energy Technology Data Exchange (ETDEWEB)

Chen, Weifeng; He, Yan; Ouyang, Gang, E-mail: gangouy@hunnu.edu.cn [Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Synergetic Innovation Center for Quantum Effects and Applications(SICQEA), Hunan Normal University, Changsha 410081 (China); Sun, Changqing [School of Electrical & Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

2016-01-15

The thermal conductivity of Si/Ge core-shell nanowires (CSNWs) is investigated on the basis of atomic-bond-relaxation consideration and continuum mechanics. An analytical model is developed to clarify the interface bond relaxation of Si/Ge CSNWs. It is found that the thermal conductivity of Si core can be modulated through covering with Ge epitaxial layers. The change of thermal conductivity in Si/Ge CSNWs should be attributed to the surface relaxation and interface mismatch between inner Si nanowire and outer Ge epitaxial layer. Our results are in well agreement with the experimental measurements and simulations, suggesting that the presented method provides a fundamental insight of the thermal conductivity of CSNWs from the atomistic origin.

TWO-DIMENSIONAL APPROXIMATION OF EIGENVALUE PROBLEMS IN SHELL THEORY: FLEXURAL SHELLS

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

The eigenvalue problem for a thin linearly elastic shell, of thickness 2e, clamped along its lateral surface is considered. Under the geometric assumption on the middle surface of the shell that the space of inextensional displacements is non-trivial, the authors obtain, as ε→0,the eigenvalue problem for the two-dimensional"flexural shell"model if the dimension of the space is infinite. If the space is finite dimensional, the limits of the eigenvalues could belong to the spectra of both flexural and membrane shells. The method consists of rescaling the variables and studying the problem over a fixed domain. The principal difficulty lies in obtaining suitable a priori estimates for the scaled eigenvalues.

Comprehensive investigation of core-shell dimer nanoparticles size, distance and thicknesses on performance of a hybrid organic-inorganic halide perovskite solar cell

Science.gov (United States)

Heidarzadeh, Hamid

2018-03-01

Significant performance enhancement in an ultrathin perovskite (CH3NH3PbI3) solar cell is done using plasmonic embedded core–shell dimer nanoparticles. Three-dimensional finite difference time-domain (FDTD) method is used. A perovskite absorber with a volume of 400 × 400 × 200 nm3 is considered. At first, a cell with one embedded nanoparticle is simulated. Absorptance of CH3NH3PbI3 absorber and gold nanoparticle are obtained. An optimization is done. Then a cell with embedded dimer nanoparticles is evaluated. The results show higher photocurrent enhancement for that in compared to a cell with one embedded nanoparticle. To further photocurrent enhancement, gold-SiO2 core–shell nanoparticles are used. Photocurrents of 23.37 mA cm‑2, 23.3 mA cm‑2, 22.5 mA cm‑2 and 21.47 mA cm‑2 are obtained for a cell with two embedded core–shell nanoparticles with core radius of 60 nm and shell thickness of 2 nm, 5 nm, 10 nm and 20 nm, respectively. It is important to mention that the photocurrent is 17.9 mA cm‑2 for reference cell and 19.8 mA cm‑2 for a cell with one embedded nanoparticle. Higher photocurrent is due to the near-field plasmonic effect.

Unified approach to the entropy of an extremal rotating BTZ black hole: Thin shells and horizon limits

Science.gov (United States)

Lemos, José P. S.; Minamitsuji, Masato; Zaslavskii, Oleg B.

2017-10-01

Using a thin shell, the first law of thermodynamics, and a unified approach, we study the thermodymanics and find the entropy of a (2 +1 )-dimensional extremal rotating Bañados-Teitelbom-Zanelli (BTZ) black hole. The shell in (2 +1 ) dimensions, i.e., a ring, is taken to be circularly symmetric and rotating, with the inner region being a ground state of the anti-de Sitter spacetime and the outer region being the rotating BTZ spacetime. The extremal BTZ rotating black hole can be obtained in three different ways depending on the way the shell approaches its own gravitational or horizon radius. These ways are explicitly worked out. The resulting three cases give that the BTZ black hole entropy is either the Bekenstein-Hawking entropy, S =A/+ 4 G , or an arbitrary function of A+, S =S (A+) , where A+=2 π r+ is the area, i.e., the perimeter, of the event horizon in (2 +1 ) dimensions. We speculate that the entropy of an extremal black hole should obey 0 ≤S (A+)≤A/+ 4 G . We also show that the contributions from the various thermodynamic quantities, namely, the mass, the circular velocity, and the temperature, for the entropy in all three cases are distinct. This study complements the previous studies in thin shell thermodynamics and entropy for BTZ black holes. It also corroborates the results found for a (3 +1 )-dimensional extremal electrically charged Reissner-Nordström black hole.

Monodisperse MnO2@NiCo2O4 core/shell nanospheres with highly opened structures as electrode materials for good-performance supercapacitors

Science.gov (United States)

Zhou, You; Ma, Li; Gan, Mengyu; Ye, Menghan; Li, Xiurong; Zhai, Yanfang; Yan, Fabing; Cao, Feifei

2018-06-01

The monodisperse MnO2@NiCo2O4 core/shell nanospheres for good-performance supercapacitors are designed and synthesized by a two-step solution-based method and a simple post annealing process. In the composite, both MnO2 (the "core") and NiCo2O4 (the "shell") are formed by the accumulation of nanoflakes. Thus, nearly all the core/shell nanoflakes are highly opened and accessible to electrolyte, making them give full play to the Faradaic reaction. Our results demonstrate that the composite electrode exhibits desirable pseudocapacitive behaviors with higher specific capacitance (1127.27 F g-1 at a current density of 1 A g-1), better rate capability (81.0% from 1 to 16 A g-1) and superior cycling stability (actually 126.8% capacitance retention after 1000 cycles and only 3.7% loss after 10,000 cycles at 10 A g-1) in 3 M KOH aqueous solution. Moreover, it offers the excellent specific energy density of 26.6 Wh kg-1 at specific power density of 800 W kg-1. The present MnO2@NiCo2O4 core/shell nanospheres with remarkable electrochemical properties are considered as potential electrode materials for the next generation supercapacitors.

UHPFRC in large span shell structures

NARCIS (Netherlands)

Ter Maten, R.N.; Grunewald, S.; Walraven, J.C.

2013-01-01

Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC) is an innovative concrete type with a high compressive strength and a far more durable character compared to conventional concrete. UHPFRC can be applied in structures with aesthetic appearance and high material efficiency. Shell structures

A Chemical-Adsorption Strategy to Enhance the Reaction Kinetics of Lithium-Rich Layered Cathodes via Double-Shell Surface Modification.

Science.gov (United States)

Guo, Lichao; Li, Jiajun; Cao, Tingting; Wang, Huayu; Zhao, Naiqin; He, Fang; Shi, Chunsheng; He, Chunnian; Liu, Enzuo

2016-09-21

Sluggish surface reaction kinetics hinders the power density of Li-ion battery. Thus, various surface modification techniques have been applied to enhance the electronic/ionic transfer kinetics. However, it is challenging to obtain a continuous and uniform surface modification layer on the prime particles with structure integration at the interface. Instead of classic physical-adsorption/deposition techniques, we propose a novel chemical-adsorption strategy to synthesize double-shell modified lithium-rich layered cathodes with enhanced mass transfer kinetics. On the basis of experimental measurement and first-principles calculation, MoO2S2 ions are proved to joint the layered phase via chemical bonding. Specifically, the Mo-O or Mo-S bonds can flexibly rotate to bond with the cations in the layered phase, leading to the good compatibility between the thiomolybdate adsorption layer and layered cathode. Followed by annealing treatment, the lithium-excess-spinel inner shell forms under the thiomolybdate adsorption layer and functions as favorable pathways for lithium and electron. Meanwhile, the nanothick MoO3-x(SO4)x outer shell protects the transition metal from dissolution and restrains electrolyte decomposition. The double-shell modified sample delivers an enhanced discharge capacity almost twice as much as that of the unmodified one at 1 A g(-1) after 100 cycles, demonstrating the superiority of the surface modification based on chemical adsorption.

Identification of parameters for superconducting generators having free or fixed outer rotor, based on tests and calculations

International Nuclear Information System (INIS)

Bratoljic, T.; Bischof, H.; Lorenzen, H.W.

1988-01-01

The generator, with its concentric and in part solid and conductive parts, is represented by a shell model, and the parameters of the system of equivalent windings are first obtained approximately using a two-dimensional analytical field calculation. The effect of the finite length, which is neglected in this field calculation, is taken into account by variation of the model geometry and material conductivity so that the Nyquist plots of the model impedances are optimally matched to those of the real system. The resulting machine model is checked and confirmed by comparing the simulation results with test measurements. It is further shown that an outer damper cylinder which is free to rotate independently provides significant mechanical relief of the shaft line during transient processes

Issues concerning outer space investments in international law ...

African Journals Online (AJOL)

Issues concerning outer space investments in international law. ... Recent improvements in technology have in essence increased the viability of outer space as the next frontier for international investment and development. In addition to ... Key words: Outer Space, Investments, International Law, International Space Station ...

Determination of K shell absorption jump factors and jump ratios of 3d transition metals by measuring K shell fluorescence parameters.

Science.gov (United States)

Kaçal, Mustafa Recep; Han, İbrahim; Akman, Ferdi

2015-01-01

Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring K-shell absorption jump factors and jump ratios for Ti, Cr, Fe, Co, Ni and Cu elements. The jump factors and jump ratios for these elements were determined by measuring K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation and transmission experimental geometry. The measured values for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature. Copyright © 2014 Elsevier Ltd. All rights reserved.

Outer scale of atmospheric turbulence

Science.gov (United States)

Lukin, Vladimir P.

2005-10-01

In the early 70's, the scientists in Italy (A.Consortini, M.Bertolotti, L.Ronchi), USA (R.Buser, Ochs, S.Clifford) and USSR (V.Pokasov, V.Lukin) almost simultaneously discovered the phenomenon of deviation from the power law and the effect of saturation for the structure phase function. During a period of 35 years we have performed successively the investigations of the effect of low-frequency spectral range of atmospheric turbulence on the optical characteristics. The influence of the turbulence models as well as a outer scale of turbulence on the characteristics of telescopes and systems of laser beam formations has been determined too.

Revisiting chameleon gravity: Thin-shell and no-shell fields with appropriate boundary conditions

International Nuclear Information System (INIS)

Tamaki, Takashi; Tsujikawa, Shinji

2008-01-01

We derive analytic solutions of a chameleon scalar field φ that couples to a nonrelativistic matter in the weak gravitational background of a spherically symmetric body, paying particular attention to a field mass m A inside of the body. The standard thin-shell field profile is recovered by taking the limit m A r c →∞, where r c is a radius of the body. We show the existence of ''no-shell'' solutions where the field is nearly frozen in the whole interior of the body, which does not necessarily correspond to the 'zero-shell' limit of thin-shell solutions. In the no-shell case, under the condition m A r c >>1, the effective coupling of φ with matter takes the same asymptotic form as that in the thin-shell case. We study experimental bounds coming from the violation of equivalence principle as well as solar-system tests for a number of models including f(R) gravity and find that the field is in either the thin-shell or the no-shell regime under such constraints, depending on the shape of scalar-field potentials. We also show that, for the consistency with local gravity constraints, the field at the center of the body needs to be extremely close to the value φ A at the extremum of an effective potential induced by the matter coupling.

Controlled facile synthesis of hierarchical CuO@MnO{sub 2} core–shell nanosheet arrays for high-performance lithium-ion battery

Energy Technology Data Exchange (ETDEWEB)

Chen, Qing; Heng, Bojun; Wang, Hai; Sun, Daming; Wang, Bixiao; Sun, Miao; Guan, Shunli; Fu, Ranyan; Tang, Yiwen, E-mail: ywtang@phy.ccnu.edu.cn

2015-08-25

Highlights: • We have facile synthesized the CuO@MnO{sub 2} nanosheet array directly on Cu substrate. • This core–shell structure was assembled as a full cell (vs LiCoO{sub 2}) for the first time. • The full cell exhibits a 127 mA h g{sup −1} at the 150 mA g{sup −1} after 100 cycle. • This strategy can be generalized to construct other hybrid nanostructures. - Abstract: We report a facile, rapid and low-cost two step approach to synthesize hierarchical CuO@MnO{sub 2} core–shell nanosheet arrays directly on Cu foil substrate. The as prepared CuO@MnO{sub 2} arrays can be directly used as integrated electrodes. Furthermore, the CuO@MnO{sub 2} nanosheet arrays were assembled with the commercial Li Ion Battery Cathode (LiCoO{sub 2}) as a full cell, which exhibited high capacity and good cycle stability (120 mA h g{sup −1} after 100 cycles at a rate of 150 mA g{sup −1}) and an excellent rate performance (a stable capacity of about 127 mA h g{sup −1} after 100 cycles of variable charging rate). The excellent performance of the CuO@MnO{sub 2} hybrids comes from their intelligent integration of the two compatible components into unique hierarchical architectures with a high specific capacity. Primary single-crystalline CuO nanosheet arrays directly grown on Cu substrates allow for efficient electrical and ionic transport. The secondary MnO{sub 2} shell provide enhanced surface area and high theoretical Li{sup +} storage capacity, and can also serve as volume spacers between neighboring CuO nanosheet arrays to maintain electrolyte penetration as well as reduce the aggregation during Li{sup +} intercalation, thus leading to improved electrochemical energy storage performance.

Plastic buckling of cylindrical shells

International Nuclear Information System (INIS)

Bandyopadhyay, K.; Xu, J.; Shteyngart, S.; Eckert, H.

1994-01-01

Cylindrical shells exhibit buckling under axial loads at stresses much less than the respective theoretical critical stresses. This is due primarily to the presence of geometrical imperfections even though such imperfections could be very small (e.g., comparable to thickness). Under internal pressure, the shell regains some of its buckling strength. For a relatively large radius-to-thickness ratio and low internal pressure, the effect can be reasonably estimated by an elastic analysis. However, for low radius-to-thickness ratios and greater pressures, the elastic-plastic collapse controls the failure load. in order to quantify the elastic-plastic buckling capacity of cylindrical shells, an analysis program was carried out by use of the computer code BOSOR5 developed by Bushnell of Lockheed Missiles and Space Company. The analysis was performed for various radius-to-thickness ratios and imperfection amplitudes. The purpose of the analytical program was to compute the buckling strength of underground cylindrical tanks, that are used for storage of nuclear wastes, for realistic geometric imperfections and internal pressure loads. This paper presents the results of the elastic-plastic analyses and compares them with other available information for various pressure loads

Plasmas in the outer heliosphere

Science.gov (United States)

Belcher, J. W.; Richardson, J. D.; Lazarus, A. J.; Gazis, P. R.; Barnes, A.

1995-01-01

We review the observed properties of the solar wind in the outer heliosphere, including observations from Voyager and the Pioneers, as well as from inner heliospheric probes as appropriate. These observations are crucial to modeling of the heliosphere and its interactions with the interstellar medium, since the wind ram pressure and its temporal variations are important in understanding the distance to the termination shock and heliopause and how those boundaries might vary in time. We focus on results since Solar Wind 7. Among the issues we will discuss are: (1) the time scales for and statistical properties of variations in the ram pressure in the outer heliosphere, and how those variations might affect the morphology of the heliospheric/interstellar medium interface; (2) the question of possible solar wind slowing in the outer heliosphere due to the pick-up of interstellar ions; (3) the issue of whether there is bulk heating of the solar wind associated either with interstellar ion pick-up or with continued heating due to stream-stream interactions; (4) evidence for latitudinal variations in solar wind properties; and (5) the 1.3 year periodicities apparent in the outer heliosphere, and the close correspondence with similar variations seen with inner heliospheric probes.

The Experimental Study of the Performance of Nano-Thin Polyelectrolyte Shell for Dental Pulp Stem Cells Immobilization.

Science.gov (United States)

Grzeczkowicz, A; Granicka, L H; Maciejewska, I; Strawski, M; Szklarczyk, M; Borkowska, M

2015-12-01

Carious is the most frequent disease of mineralized dental tissues which might result in dental pulp inflammation and mortality. In such cases an endodontic treatment is the only option to prolong tooth functioning in the oral cavity; however, in the cases of severe pulpitis, especially when complicated with periodontal tissue inflammation, the endodontic treatment might not be enough to protect against tooth loss. Thus, keeping the dental pulp viable and/or possibility of the reconstruction of a viable dental pulp complex, appears to become a critical factor for carious and/or pulp inflammation treatment. The nowadays technologies, which allow handling dental pulp stem cells (DPSC), seem to bring us closer to the usage of dental stem cells for tooth tissues reconstruction. Thus, DPSC immobilized within nano-thin polymeric shells, allowing for a diffusion of produced factors and separation from bacteria, may be considered as a cover system supporting technology of dental pulp reconstruction. The DPSC were immobilized using a layer-by-layer technique within nano-thin polymeric shells constructed and modified by nanostructure involvement to ensure the layers stability and integrity as well as separation from bacterial cells. The cytotoxity of the material used for membrane production was assessed on the model of adherent cells. The performance of DPSC nano-coating was assessed in vitro. Membrane coatings showed no cytotoxicity on the immobilized cells. The presence of coating shell was confirmed with flow cytometry, atomic force microscopy and visualized with fluorescent microscopy. The transfer of immobilized DPSC within the membrane system ensuring cells integrity, viability and protection from bacteria should be considered as an alternative method for dental tissues transportation and regeneration.

Applicability assessment of plug weld to ITER vacuum vessel by crack propagation analysis