Nanometer size wear debris generated from ultra high molecular weight polyethylene in vivo

Czech Academy of Sciences Publication Activity Database

Lapčíková, Monika; Šlouf, Miroslav; Dybal, Jiří; Zolotarevova, E.; Entlicher, G.; Pokorný, D.; Gallo, J.; Sosna, A.

2009-01-01

Roč. 266, 1-2 (2009), s. 349-355 ISSN 0043-1648 R&D Projects: GA MŠk 2B06096 Institutional research plan: CEZ:AV0Z40500505 Keywords : ultra high molecular weight polyethylene * nanometer size wear debris * morphology of wear particles Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.771, year: 2009

Nanometer scale materials - characterization and fabrication

International Nuclear Information System (INIS)

Murday, J.S.; Colton, R.J.; Rath, B.B.

1993-01-01

Materials and solid state scientists have made excellent progress in understanding material behavior in length scales from microns to meters. Below a micron, the lack of analytical prowess has been a deterrent. At the atomic scale, chemistry and atomic/molecular physics have also contributed significant understanding of matter. The maturity of these three communities, materials, solid state physics, atomic/molecular physics/chemistry, coupled with the development of analytical capability for nanometer-sized structures, promises to broaden our grasp of materials behavior into the last realm of unexplored size scales-nanometer. The motivation for this effort is driven both by the expectation of novel properties as well as by the potential solution to long standing technological issues. Critical scale lengths for many material properties fall in the nanometer range, examples include superconductor coherence lengths, electron inelastic mean free paths, electron wavelengths in solids, critical lengths for dislocation generation. Structures of nanometer size will undoubtedly show behavior unexpected from experience at the larger and smaller scales. Many technological problems such as adhesion, friction, corrosion, elasticity and fracture are believed to depend critically on nanometer scale phenomena. The millennia-old efforts to improve materials behavior have undoubtedly been slowed by our inability to 'observe' in this size range. (orig.)

The voltammetric responses of nanometer-sized electrodes in weakly supported electrolyte: A theoretical study

International Nuclear Information System (INIS)

Liu Yuwen; Zhang Qianfan; Chen Shengli

2010-01-01

The effect of the supporting electrolyte concentration on the interfacial profiles and voltammetric responses of nanometer-sized disk electrodes have been investigated theoretically by combining the Poisson-Nernst-Planck (PNP) theory and Butler-Volmer (BV) equation. The PNP-theory is used to treat the nonlinear couplings of electric field, concentration field and dielectric field at electrochemical interface without the electroneutrality assumption that has been long adopted in various voltammetric theories for macro/microelectrodes. The BV equation is modified by using the Frumkin correction to account for the effect of the diffuse double layer potential on interfacial electron-transfer (ET) rate and by including a distance-dependent ET probability in the expression of rate constant to describe the radial heterogeneity of the ET rate constant at nanometer-sized disk electrodes. The computed voltammetric responses for disk electrodes larger than 200 nm in radii in the absence of the excess of the supporting electrolyte using the present theoretical scheme show reasonable agreements with the predications of the conventional microelectrode voltammetric theory which uses the combined Nernst-Planck equation and electroneutrality equation to describe the mixed electromigration-diffusion mass transport without including the possible effects of the diffuse double layer (Amatore et al. ). For electrodes smaller than 200 nm, however, the voltammetric responses predicated by the present theory exhibit significant deviation from the microelectrode theory. It is shown that the deviations are mainly resulted from the overlap between the diffuse double layer and the concentration depletion layer (CDL) at nanoscale electrochemical interfaces in weakly supported media, which will result in the invalidation of the electroneutrality condition in CDL, and from the radial inhomogeneity of ET probability at nanometer-sized disk electrodes.

The voltammetric responses of nanometer-sized electrodes in weakly supported electrolyte: A theoretical study

Energy Technology Data Exchange (ETDEWEB)

Liu Yuwen; Zhang Qianfan [Hubei Electrochemical Power Sources Key Laboratory, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China); Chen Shengli, E-mail: slchen@whu.edu.c [Hubei Electrochemical Power Sources Key Laboratory, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China)

2010-11-30

The effect of the supporting electrolyte concentration on the interfacial profiles and voltammetric responses of nanometer-sized disk electrodes have been investigated theoretically by combining the Poisson-Nernst-Planck (PNP) theory and Butler-Volmer (BV) equation. The PNP-theory is used to treat the nonlinear couplings of electric field, concentration field and dielectric field at electrochemical interface without the electroneutrality assumption that has been long adopted in various voltammetric theories for macro/microelectrodes. The BV equation is modified by using the Frumkin correction to account for the effect of the diffuse double layer potential on interfacial electron-transfer (ET) rate and by including a distance-dependent ET probability in the expression of rate constant to describe the radial heterogeneity of the ET rate constant at nanometer-sized disk electrodes. The computed voltammetric responses for disk electrodes larger than 200 nm in radii in the absence of the excess of the supporting electrolyte using the present theoretical scheme show reasonable agreements with the predications of the conventional microelectrode voltammetric theory which uses the combined Nernst-Planck equation and electroneutrality equation to describe the mixed electromigration-diffusion mass transport without including the possible effects of the diffuse double layer (Amatore et al. ). For electrodes smaller than 200 nm, however, the voltammetric responses predicated by the present theory exhibit significant deviation from the microelectrode theory. It is shown that the deviations are mainly resulted from the overlap between the diffuse double layer and the concentration depletion layer (CDL) at nanoscale electrochemical interfaces in weakly supported media, which will result in the invalidation of the electroneutrality condition in CDL, and from the radial inhomogeneity of ET probability at nanometer-sized disk electrodes.

Strengthening of metallic alloys with nanometer-size oxide dispersions

Science.gov (United States)

Flinn, John E.; Kelly, Thomas F.

1999-01-01

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains.

Strengthening of metallic alloys with nanometer-size oxide dispersions

Science.gov (United States)

Flinn, J.E.; Kelly, T.F.

1999-06-01

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains. 20 figs.

Depositing nanometer-sized particles of metals onto carbon allotropes

Science.gov (United States)

Watson, Kent A. (Inventor); Fallbach, Michael J. (Inventor); Ghose, Sayata (Inventor); Smith, Joseph G. (Inventor); Delozier, Donavon M. (Inventor); Connell, John W. (Inventor)

2010-01-01

A process for depositing nanometer-sized metal particles onto a substrate in the absence of aqueous solvents, organic solvents, and reducing agents, and without any required pre-treatment of the substrate, includes preparing an admixture of a metal compound and a substrate by dry mixing a chosen amount of the metal compound with a chosen amount of the substrate; and supplying energy to the admixture in an amount sufficient to deposit zero valance metal particles onto the substrate. This process gives rise to a number of deposited metallic particle sizes which may be controlled. The compositions prepared by this process are used to produce polymer composites by combining them with readily available commodity and engineering plastics. The polymer composites are used as coatings, or they are used to fabricate articles, such as free-standing films, fibers, fabrics, foams, molded and laminated articles, tubes, adhesives, and fiber reinforced articles. These articles are well-suited for many applications requiring thermal conductivity, electrical conductivity, antibacterial activity, catalytic activity, and combinations thereof.

Mechanism of the superior mechanical strength of nanometer-sized metal single crystals revealed

KAUST Repository

Afify, N. D.

2013-10-01

Clear understanding of the superior mechanical strength of nanometer-sized metal single crystals is required to derive advanced mechanical components retaining such superiority. Although high quality studies have been reported on nano-crystalline metals, the superiority of small single crystals has neither been fundamentally explained nor quantified to this date. Here we present a molecular dynamics study of aluminum single crystals in the size range from 4.1 nm to 40.5 nm. We show that the ultimate mechanical strength deteriorates exponentially as the single crystal size increases. The small crystals superiority is explained by their ability to continuously form vacancies and to recover them. © 2013 Published by Elsevier B.V.

Fabrication and characterization of a nanometer-sized optical fiber electrode based on selective chemical etching for scanning electrochemical/optical microscopy.

Science.gov (United States)

Maruyama, Kenichi; Ohkawa, Hiroyuki; Ogawa, Sho; Ueda, Akio; Niwa, Osamu; Suzuki, Koji

2006-03-15

We have already reported a method for fabricating ultramicroelectrodes (Suzuki, K. JP Patent, 2004-45394, 2004). This method is based on the selective chemical etching of optical fibers. In this work, we undertake a detailed investigation involving a combination of etched optical fibers with various types of tapered tip (protruding-shape, double- (or pencil-) shape and triple-tapered electrode) and insulation with electrophoretic paint. Our goal is to establish a method for fabricating nanometer-sized optical fiber electrodes with high reproducibility. As a result, we realized pencil-shaped and triple-tapered electrodes that had radii in the nanometer range with high reproducibility. These nanometer-sized electrodes showed well-defined sigmoidal curves and stable diffusion-limited responses with cyclic voltammetry. The pencil-shaped optical fiber, which has a conical tip with a cone angle of 20 degrees , was effective for controlling the electrode radius. The pencil-shaped electrodes had higher reproducibility and smaller electrode radii (r(app) etched optical fiber electrodes. By using a pencil-shaped electrode with a 105-nm radius as a probe, we obtained simultaneous electrochemical and optical images of an implantable interdigitated array electrode. We achieved nanometer-scale resolution with a combination of scanning electrochemical microscopy SECM and optical microscopy. The resolution of the electrochemical and optical images indicated sizes of 300 and 930 nm, respectively. The neurites of living PC12 cells were also successfully imaged on a 1.6-microm scale by using the negative feedback mode of an SECM.

Optical properties of (nanometer MCM-41)-(malachite green) composite materials

International Nuclear Information System (INIS)

Li Xiaodong; Zhai Qingzhou; Zou Mingqiang

2010-01-01

Nanosized materials loaded with organic dyes are of interest with respect to novel optical applications. The optical properties of malachite green (MG) in MCM-41 are considerably influenced by the limited nanoporous channels of nanometer MCM-41. Nanometer MCM-41 was synthesized by tetraethyl orthosilicate (TEOS) as the source of silica and cetyltrimethylammonium bromide (CTMAB) as the template. The liquid-phase grafting method has been employed for incorporation of the malachite green molecules into the channels of nanometer MCM-41. A comparative study has been carried out on the adsorption of the malachite green into modified MCM-41 and unmodified MCM-41. The modified MCM-41 was synthesized using a silylation reagent, trimethychlorosilane (TMSCl), which functionalized the surface of nanometer MCM-41 for proper host-guest interaction. The prepared (nanometer MCM-41)-MG samples have been studied by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, low-temperature nitrogen adsorption-desorption technique at 77 K, Raman spectra and luminescence studies. In the prepared (nanometer MCM-41)-MG composite materials, the frameworks of the host molecular sieve were kept intact and the MG located inside the pores of MCM-41. Compared with the MG, it is found that the prepared composite materials perform a considerable luminescence. The excitation and emission spectra of MG in both modified MCM-41 and unmodified MCM-41 were examined to explore the structural effects on the optical properties of MG. The results of luminescence spectra indicated that the MG molecules existed in monomer form within MCM-41. However, the luminescent intensity of MG incorporated in the modified MCM-41 are higher than that of MG encapsulated in unmodified MCM-41, which may be due to the anchored methyl groups on the channels of the nanometer MCM-41 and the strong host-guest interactions. The steric effect from the pore size of the host materials is significant. Raman

Transmission electron microscopy studies on nanometer-sized ω phase produced in Gum Metal

International Nuclear Information System (INIS)

Yano, Takaaki; Murakami, Yasukazu; Shindo, Daisuke; Hayasaka, Yuichiro; Kuramoto, Shigeru

2010-01-01

The morphology, numerical density and average spacing of the ω phase formed in Gum Metal, a Ti-based alloy showing unique mechanical properties, were studied by transmission electron microscopy. Based on dark-field image observations and precise thickness measurements using a thin-foil specimen, the average spacing of the nanometer-sized ω phase was determined to be 6 nm. This spacing appeared to be sufficiently small for trapping dislocations. The results are discussed in conjunction with the dislocation-free deformation mechanism proposed for Gum Metal.

Quantum decrease of capacitance in a nanometer-sized tunnel junction

Science.gov (United States)

Untiedt, C.; Saenz, G.; Olivera, B.; Corso, M.; Sabater, C.; Pascual, J. I.

2013-03-01

We have studied the capacitance of the tunnel junction defined by the tip and sample of a Scanning Tunnelling Microscope through the measurement of the electrostatic forces and impedance of the junction. A decrease of the capacitance when a tunnel current is present has shown to be a more general phenomenon as previously reported in other systems. On another hand, an unexpected reduction of the capacitance is also observed when increasing the applied voltage above the work function energy of the electrodes to the Field Emission (FE) regime, and the decrease of capacitance due to a single FE-Resonance has been characterized. All these effects should be considered when doing measurements of the electronic characteristics of nanometer-sized electronic devices and have been neglected up to date. Spanish government (FIS2010-21883-C02-01, CONSOLIDER CSD2007-0010), Comunidad Valenciana (ACOMP/2012/127 and PROMETEO/2012/011)

The Ages in a Self-Suspended Nanoparticle Liquid

KAUST Repository

Agarwal, Praveen; Qi, Haibo; Archer, Lynden A.

2010-01-01

Telomers ionically tethered to nanometer-sized particles yield self-suspended, nanoparticle-Iaden liquids with unusual dynamical features. By subjecting these suspensions to controlled, modest shear strains, we find that their flow behaviors

Graphene nanoribbon field effect transistor for nanometer-size on-chip temperature sensor

Science.gov (United States)

Banadaki, Yaser M.; Srivastava, Ashok; Sharifi, Safura

2016-04-01

Graphene has been extensively investigated as a promising material for various types of high performance sensors due to its large surface-to-volume ratio, remarkably high carrier mobility, high carrier density, high thermal conductivity, extremely high mechanical strength and high signal-to-noise ratio. The power density and the corresponding die temperature can be tremendously high in scaled emerging technology designs, urging the on-chip sensing and controlling of the generated heat in nanometer dimensions. In this paper, we have explored the feasibility of a thin oxide graphene nanoribbon (GNR) as nanometer-size temperature sensor for detecting local on-chip temperature at scaled bias voltages of emerging technology. We have introduced an analytical model for GNR FET for 22nm technology node, which incorporates both thermionic emission of high-energy carriers and band-to-band-tunneling (BTBT) of carriers from drain to channel regions together with different scattering mechanisms due to intrinsic acoustic phonons and optical phonons and line-edge roughness in narrow GNRs. The temperature coefficient of resistivity (TCR) of GNR FET-based temperature sensor shows approximately an order of magnitude higher TCR than large-area graphene FET temperature sensor by accurately choosing of GNR width and bias condition for a temperature set point. At gate bias VGS = 0.55 V, TCR maximizes at room temperature to 2.1×10-2 /K, which is also independent of GNR width, allowing the design of width-free GNR FET for room temperature sensing applications.

Preparation, characterization and optical properties of Lanthanum-(nanometer MCM-41) composite materials

International Nuclear Information System (INIS)

Zhai, Q. Z.; Wang, P.

2008-01-01

Nanometer MCM-41 molecular sieve was prepared under a base condition by using cetyltrimethylammonium bromide as template and tetraethyl orthosilicate as silica source by means of hydrothermal method. Lanthanum(III) was incorporated into the nanometer MCM-41 by a liquid phase grafting method. The prepared nano composite materials were characterized by means of powder X-ray diffraction, spectrophotometric analysis, Fourier transform infrared spectroscopy, low temperature nitrogen adsorption-desorption technique, solid diffuse reflectance absorption spectra and luminescence. The powder X-ray diffraction studies show that the nanometer MCM-41 molecular sieve is successfully prepared. The highly ordered meso porous two-dimensional hexagonal channel structure and framework of the support MCM-41 is retained intact in the prepared composite material La-(nanometer MCM-41). The spectrophotometric analysis indicates that lanthanum exists in the prepared nano composite materials. The Fourier transform infrared spectra indicate that the framework of the MCM-41 molecular sieve still remains in the prepared nano composite materials and some framework vibration peaks show blue shifts relative to those of the MCM-41 molecular sieve. The low temperature nitrogen adsorption-desorption indicates that the guest locales in the channel of the molecular sieve. Compared with bulk lanthanum oxide, the guest in the channel of the molecular sieve has smaller particle size and shows a significant blue shift of optical absorption band in solid diffuse reflectance absorption spectra. The observed blue shift in the solid state diffuse reflectance absorption spectra of the lanthanum-(nanometer MCM-41) sample show the obvious stereoscopic confinement effect of the channel of the host on the guest, which further indicates the successful encapsulation of the guest in the host. The La-(nanometer MCM-41) sample shows luminescence

Obtaining of iron particles of nanometer size in a natural zeolite; Obtencion de particulas de hierro de tamano nanometrico en una zeolita natural

Energy Technology Data Exchange (ETDEWEB)

Xingu C, E. G.

2013-07-01

The zeolites are aluminosilicates with cavities that can act as molecular sieve. Their crystalline structure is formed by tetrahedrons that get together giving place to a three-dimensional net, in which each oxygen is shared by two silicon atoms, being this way part of the tecto silicate minerals, its external and internal areas reach the hundred square meters for gram, they are located in a natural way in a large part of earth crust and also exist in a synthetic way. In Mexico there are different locations of zeolitic material whose important component is the clinoptilolite. In this work the results of three zeolitic materials coming from San Luis Potosi are shown, the samples were milled and sieved for its initial characterization, to know its chemical composition, crystalline phases, morphology, topology and thermal behavior before and after its homo-ionization with sodium chloride, its use as support of iron particles of nanometer size. The description of the synthesis of iron particles of nanometer size is also presented, as well as the comparison with the particles of nanometer size synthesized without support after its characterization. The characterization techniques used during the experimental work were: Scanning electron microscopy, X-ray diffraction, Infrared spectroscopy, specific area by means of BET and thermogravimetry analysis. (Author)

Anomalous or regular capacitance? The influence of pore size dispersity on double-layer formation

Science.gov (United States)

Jäckel, N.; Rodner, M.; Schreiber, A.; Jeongwook, J.; Zeiger, M.; Aslan, M.; Weingarth, D.; Presser, V.

2016-09-01

The energy storage mechanism of electric double-layer capacitors is governed by ion electrosorption at the electrode surface. This process requires high surface area electrodes, typically highly porous carbons. In common organic electrolytes, bare ion sizes are below one nanometer but they are larger when we consider their solvation shell. In contrast, ionic liquid electrolytes are free of solvent molecules, but cation-anion coordination requires special consideration. By matching pore size and ion size, two seemingly conflicting views have emerged: either an increase in specific capacitance with smaller pore size or a constant capacitance contribution of all micro- and mesopores. In our work, we revisit this issue by using a comprehensive set of electrochemical data and a pore size incremental analysis to identify the influence of certain ranges in the pore size distribution to the ion electrosorption capacity. We see a difference in solvation of ions in organic electrolytes depending on the applied voltage and a cation-anion interaction of ionic liquids in nanometer sized pores.

Synthesis of nanometer-sized fayalite and magnesium-iron(II) mixture olivines

Energy Technology Data Exchange (ETDEWEB)

Qafoku, Odeta; Ilton, Eugene S.; Bowden, Mark E.; Kovarik, Libor; Zhang, Xin; Kukkadapu, Ravi K.; Engelhard, Mark H.; Thompson, Christopher J.; Schaef, Herbert T.; McGrail, Bernard Peter; Rosso, Kevin M.; Loring, John S.

2018-04-01

Olivines are divalent orthosilicates with important geologic, biological, and industrial significance and are typically comprised of mixtures of Mg2+ and Fe2+ ranging from forsterite (Mg2SiO4) to fayalite (Fe2SiO4). Investigating the role of Fe(II) in olivine reactivity requires the ability to synthesize olivines that are nanometer-sized, have different percentages of Mg2+ and Fe2+, and have good bulk and surface purity. This article demonstrates a new method for synthesizing nanosized fayalite and Mg-Fe mixture olivines. First, carbonaceous precursors are generated from sucrose, PVA, colloidal silica, Mg2+, and Fe3+. Second, these precursors are calcined in air to burn carbon and create mixtures of Fe(III)-oxides, forsterite, and SiO2. Finally, calcination in reducing CO-CO2 gas buffer leads to Fe(II)-rich olivines. XRD, Mössbauer, and IR analyses verify good bulk purity and composition. XPS indicates that surface iron is in its reduced Fe(II) form, and surface Si is consistent with olivine. SEM shows particle sizes predominately between 50 and 450 nm, and BET surface areas are 2.8-4.2 m2/g. STEM HAADF analysis demonstrates even distributions of Mg and Fe among the available M1 and M2 sites of the olivine crystals. These nanosized Fe(II)-rich olivines are suitable for laboratory studies with in situ probes that require mineral samples with high reactivity at short timescales.

Surface effects on ionic Coulomb blockade in nanometer-size pores.

Science.gov (United States)

Tanaka, Hiroya; Iizuka, Hideo; Pershin, Yuriy V; Ventra, Massimiliano Di

2018-01-12

Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic counterpart. Here, we investigate this phenomenon extensively using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in the ionic Coulomb blockade. Our numerical results reveal the following general trends. First, the nanopore selectivity changes with its diameter, and the nanopore position in the membrane influences the current strength. Second, the ionic transport through the nanopore takes place in a hopping-like fashion over a set of discretized states caused by local electric fields due to membrane atoms. In some cases, this creates a slow-varying 'crystal-like' structure of ions inside the nanopore. Third, while at a given voltage, the resistance of the nanopore depends on its length, the slope of this dependence appears to be independent of the molarity of ions. An effective kinetic model that captures the ionic Coulomb blockade behavior observed in MD simulations is formulated.

Surface effects on ionic Coulomb blockade in nanometer-size pores

Science.gov (United States)

Tanaka, Hiroya; Iizuka, Hideo; Pershin, Yuriy V.; Di Ventra, Massimiliano

2018-01-01

Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic counterpart. Here, we investigate this phenomenon extensively using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in the ionic Coulomb blockade. Our numerical results reveal the following general trends. First, the nanopore selectivity changes with its diameter, and the nanopore position in the membrane influences the current strength. Second, the ionic transport through the nanopore takes place in a hopping-like fashion over a set of discretized states caused by local electric fields due to membrane atoms. In some cases, this creates a slow-varying ‘crystal-like’ structure of ions inside the nanopore. Third, while at a given voltage, the resistance of the nanopore depends on its length, the slope of this dependence appears to be independent of the molarity of ions. An effective kinetic model that captures the ionic Coulomb blockade behavior observed in MD simulations is formulated.

Tracing temperature in a nanometer size region in a picosecond time period.

Science.gov (United States)

Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

2015-08-21

Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

Stochastic modelling in design of mechanical properties of nanometals

International Nuclear Information System (INIS)

Tengen, T.B.; Wejrzanowski, T.; Iwankiewicz, R.; Kurzydlowski, K.J.

2010-01-01

Polycrystalline nanometals are being fabricated through different processing routes and conditions. The consequence is that nanometals having the same mean grain size may have different grain size dispersion and, hence, may have different material properties. This has often led to conflicting reports from both theoretical and experimental findings about the evolutions of the mechanical properties of nanomaterials. The present paper employs stochastic model to study the impact of microstructure evolution during grain growth on the mechanical properties of polycrystalline nanometals. The stochastic model for grain growth and the stochastic model for changes in mechanical properties of nanomaterials are proposed. The model for the mechanical properties developed is tested on aluminium samples.Many salient features of the mechanical properties of the aluminium samples are revealed. The results show that the different mechanisms of grain growth impart different nature of response to the material mechanical properties. The conventional, homologous and anomalous temperature dependences of the yield stress have also been revealed to be due to different nature of interactions of the microstructures during evolution.

Synthesis of nanometer-size inorganic materials for the examination of particle size effects on heterogeneous catalysis

Science.gov (United States)

Emerson, Sean Christian

The effect of acoustic and hydrodynamic cavitation on the precipitation of inorganic catalytic materials, specifically titania supported gold, was investigated. The overall objective was to understand the fundamental factors involved in synthesizing nanometer-size catalytic materials in the 1--10 nm range in a cavitating field. Materials with grain sizes in this range have been associated with enhanced catalytic activity compared to larger grain size materials. A new chemical approach was used to produce titania supported gold by co-precipitation with higher gold yields compared to other synthesis methods. Using this approach, it was determined that acoustic cavitation was unable to influence the gold mean crystallite size compared to non-sonicated catalysts. However, gold concentration on the catalysts was found to be very important for CO oxidation activity. By decreasing the gold concentration from a weight loading of 0.50% down to approximately 0.05%, the rate of reaction per mole of gold was found to increase by a factor of 19. Hydrodynamic cavitation at low pressures (6.9--48 bar) was determined to have no effect on gold crystallite size at a fixed gold content for the same precipitation technique used in the acoustic cavitation studies. By changing the chemistry of the precipitation system, however, it was found that a synergy existed between the dilution of the gold precursor solution, the orifice diameter, and the reducing agent addition rate. Individually, these factors were found to have little effect and only their interaction allowed gold grain size control in the range of 8--80 nm. Further modification of the system chemistry and the use of hydrodynamic cavitation at pressures in excess of 690 bar allowed the systematic control of gold crystallite size in the range of 2--9 nm for catalysts containing 2.27 +/- 0.17% gold. In addition, it was shown that the enhanced mixing due to cavitation led to larger gold yields compared to classical syntheses. The

Peri-Implant Endosseous Healing Properties of Dual Acid-Etched Mini-Implants with a Nanometer-Sized Deposition of CaP : A Histological and Histomorphometric Human Study

NARCIS (Netherlands)

Telleman, Gerdien; Albrektsson, Tomas; Hoffman, Maria; Johansson, Carina B.; Vissink, Arjan; Meijer, Henny J. A.; Raghoebar, Gerry M.

2010-01-01

Purpose: The aim of this histological and histomorphometric study was to compare the early peri-implant endosseous healing properties of a dual acid-etched (DAE) surface (Osseotite (R), Implant Innovations Inc., Palm Beach Gardens, FL, USA) with a DAE surface modified with nanometer-sized calcium

Liquid-liquid phase separation in aerosol particles: Imaging at the Nanometer Scale

Energy Technology Data Exchange (ETDEWEB)

O' Brien, Rachel; Wang, Bingbing; Kelly, Stephen T.; Lundt, Nils; You, Yuan; Bertram, Allan K.; Leone, Stephen R.; Laskin, Alexander; Gilles, Mary K.

2015-04-21

Atmospheric aerosols can undergo phase transitions including liquid-liquid phase separation (LLPS) while responding to changes in the ambient relative humidity (RH). Here, we report results of chemical imaging experiments using environmental scanning electron microscopy (ESEM) and scanning transmission x-ray microscopy (STXM) to investigate the LLPS of micron sized particles undergoing a full hydration-dehydration cycle. Internally mixed particles composed of ammonium sulfate (AS) and either: limonene secondary organic carbon (LSOC), a, 4-dihydroxy-3-methoxybenzeneaceticacid (HMMA), or polyethylene glycol (PEG-400) were studied. Events of LLPS with apparent core-shell particle morphology were observed for all samples with both techniques. Chemical imaging with STXM showed that both LSOC/AS and HMMA/AS particles were never homogeneously mixed for all measured RH’s above the deliquescence point and that the majority of the organic component was located in the shell. The shell composition was estimated as 65:35 organic: inorganic in LSOC/AS and as 50:50 organic: inorganic for HMMA/AS. PEG-400/AS particles showed fully homogeneous mixtures at high RH and phase separated below 89-92% RH with an estimated 50:50% organic to inorganic mix in the shell. These two chemical imaging techniques are well suited for in-situ analysis of the hygroscopic behavior, phase separation, and surface composition of collected ambient aerosol particles.

Passive behavior of a bulk nanostructured 316L austenitic stainless steel consisting of nanometer-sized grains with embedded nano-twin bundles

International Nuclear Information System (INIS)

Li, Tianshu; Liu, Li; Zhang, Bin; Li, Ying; Yan, Fengkai; Tao, Nairong; Wang, Fuhui

2014-01-01

Highlights: • Nanometer-grains (NG) and bundles of nano-twins (NT) is synthesized in 316L. • (NG + NT) and NT enhance the concentration of active Fe Fe in the passive film. • (NG + NT) and NT enhance the passive ability. • A Cr 0 -enriched layer forms at the passive film/metal interface. - Abstract: The passive behavior of a bulk nanostructured 316L austenitic stainless steel consisting of nanometer-sized grains (NG) and nano-twin bundles (NT) are investigated. The electrochemical results indicate that the spontaneous passivation ability and growth rate of passive film are improved. The X-ray photoelectron spectroscopy (XPS) shows that a Cr 0 -enriched layer forms at the passive film/metal interface. More nucleation sites afforded by the nanostructures and the enhanced diffusion rate of charged species across the passive film are believed to be responsible for the improved passive ability. The PDM model is introduced to elaborate the microscopic process of passivation

NANOMETER SUPERSTRUCTURE IN LIQUID ALKALI THALLIUM ALLOYS

NARCIS (Netherlands)

XU, R; VERKERK, P; HOWELLS, WS; DEWIJS, GA; VANDERHORST, F; VANDERLUGT, W

1993-01-01

Structure factors obtained from neutron diffraction measurements on liquid K-Tl and Cs-Tl alloys exhibit large prepeaks at approximately 0.77 angstrom-1 and 0.70 angstrom-1, respectively. It is concluded that the liquid contains large units of thallium atoms, possibly bearing some resemblance to

Simulation of Electrical Discharge Initiated by a Nanometer-Sized Probe in Atmospheric Conditions

International Nuclear Information System (INIS)

Chen Ran; Chen Chilai; Liu Youjiang; Wang Huanqin; Kong Deyi; Ma Yuan; Cada Michael; Brugger Jürgen

2013-01-01

In this paper, a two-dimensional nanometer scale tip-plate discharge model has been employed to study nanoscale electrical discharge in atmospheric conditions. The field strength distributions in a nanometer scale tip-to-plate electrode arrangement were calculated using the finite element analysis (FEA) method, and the influences of applied voltage amplitude and frequency as well as gas gap distance on the variation of effective discharge range (EDR) on the plate were also investigated and discussed. The simulation results show that the probe with a wide tip will cause a larger effective discharge range on the plate; the field strength in the gap is notably higher than that induced by the sharp tip probe; the effective discharge range will increase linearly with the rise of excitation voltage, and decrease nonlinearly with the rise of gap length. In addition, probe dimension, especially the width/height ratio, affects the effective discharge range in different manners. With the width/height ratio rising from 1:1 to 1:10, the effective discharge range will maintain stable when the excitation voltage is around 50 V. This will increase when the excitation voltage gets higher and decrease as the excitation voltage gets lower. Furthermore, when the gap length is 5 nm and the excitation voltage is below 20 V, the diameter of EDR in our simulation is about 150 nm, which is consistent with the experiment results reported by other research groups. Our work provides a preliminary understanding of nanometer scale discharges and establishes a predictive structure-behavior relationship

Preparation and Characterization of Some Nanometal Oxides Using Microwave Technique and Their Application to Cotton Fabrics

Directory of Open Access Journals (Sweden)

M. Gouda

2015-01-01

Full Text Available The objective of this paper is the synthesis of some nanometal oxides via microwave irradiation technique and their application to augment multifunctional properties of cotton fabric. Cotton fabrics containing nanometal oxides were prepared via a thiol-modification of cotton fabric samples and then dipped into the metal salt solutions precursors and transferred to the microwave oven. The surface morphology and quantitative analysis of the obtained modified cotton fabrics containing nanometal oxides were studied by scanning electron microscopy coupled with high energy dispersive X-ray (SEM-EDX. The shape and distribution of nanometal oxide inside the fabric samples were analyzed by transmission electron microscopy of cross-section fabric samples. The iron oxide nanoparticles had a nanosphere with particle size diameter 15–20 nm, copper oxide nanoparticles had a nanosphere with particle size diameter 25–30 nm, and cobalt oxide nanoparticles had a nanotube-like shape with a length of 100–150 nanometer and a diameter of ~58 nanometer, whereas the manganese oxide nanoparticles had a linear structure forming nanorods with a diameter of 50–55 nanometer and a length of 70–80 nanometers. Antibacterial activity was evaluated quantitatively against gram-positive bacteria such as Staphylococcus aureus and gram-negative bacteria such as Escherichia coli, UV-protection activity was analyzed using UV-DRS spectroscopy, and flame retardation of prepared fabric samples was evaluated according to the limiting oxygen index (LOI. Results revealed that the prepared fabric sample containing nanometal oxide possesses improved antibacterial, LOI, and UV-absorbing efficiency. Moreover, the metal oxide nanoparticles did not leach out the fabrics by washing even after 30 laundering washing cycles.

Synthesis of nanocrystalline TiO 2 thin films by liquid phase ...

Indian Academy of Sciences (India)

A transparent, high purity titanium dioxide thin film composed of densely packed nanometer sized grains has been successfully deposited on a glass substrate at 30°C from an aqueous solution of TiO2–HF with the addition of boric acid as a scavenger by liquid phase deposition technique. From X-ray diffraction ...

Characterization and Functionality of Immidazolium Ionic Liquids Modified Magnetic Nanoparticles

Directory of Open Access Journals (Sweden)

Ying Li

2013-01-01

Full Text Available 1,3-Dialkylimidazolium-based ionic liquids were chemically synthesized and bonded on the surface of magnetic nanoparticles (MNPs with easy one-step reaction. The obtained six kinds of ionic liquid modified MNPs were characterized with transmission electron microscopy, thermogravimetric analysis, magnetization, and FTIR, which owned the high adsorption capacity due to the nanometer size and high-density modification with ionic liquids. Functionality of MNPs with ionic liquids greatly influenced the solubility of the MNPs with organic solvents depending on the alkyl chain length and the anions of the ionic liquids. Moreover, the obtained MNPs showed the specific extraction efficiency to organic pollutant, polycyclic aromatic hydrocarbons, while superparamagnetic property of the MNPs facilitated the convenient separation of MNPs from the bulks water samples.

Size-dependent elastic/inelastic behavior of enamel over millimeter and nanometer length scales.

Science.gov (United States)

Ang, Siang Fung; Bortel, Emely L; Swain, Michael V; Klocke, Arndt; Schneider, Gerold A

2010-03-01

The microstructure of enamel like most biological tissues has a hierarchical structure which determines their mechanical behavior. However, current studies of the mechanical behavior of enamel lack a systematic investigation of these hierarchical length scales. In this study, we performed macroscopic uni-axial compression tests and the spherical indentation with different indenter radii to probe enamel's elastic/inelastic transition over four hierarchical length scales, namely: 'bulk enamel' (mm), 'multiple-rod' (10's microm), 'intra-rod' (100's nm with multiple crystallites) and finally 'single-crystallite' (10's nm with an area of approximately one hydroxyapatite crystallite). The enamel's elastic/inelastic transitions were observed at 0.4-17 GPa depending on the length scale and were compared with the values of synthetic hydroxyapatite crystallites. The elastic limit of a material is important as it provides insights into the deformability of the material before fracture. At the smallest investigated length scale (contact radius approximately 20 nm), elastic limit is followed by plastic deformation. At the largest investigated length scale (contact size approximately 2 mm), only elastic then micro-crack induced response was observed. A map of elastic/inelastic regions of enamel from millimeter to nanometer length scale is presented. Possible underlying mechanisms are also discussed. (c) 2009 Elsevier Ltd. All rights reserved.

Significant enhancement of magnetoresistance with the reduction of particle size in nanometer scale

Science.gov (United States)

Das, Kalipada; Dasgupta, P.; Poddar, A.; Das, I.

2016-01-01

The Physics of materials with large magnetoresistance (MR), defined as the percentage change of electrical resistance with the application of external magnetic field, has been an active field of research for quite some times. In addition to the fundamental interest, large MR has widespread application that includes the field of magnetic field sensor technology. New materials with large MR is interesting. However it is more appealing to vast scientific community if a method describe to achieve many fold enhancement of MR of already known materials. Our study on several manganite samples [La1−xCaxMnO3 (x = 0.52, 0.54, 0.55)] illustrates the method of significant enhancement of MR with the reduction of the particle size in nanometer scale. Our experimentally observed results are explained by considering model consisted of a charge ordered antiferromagnetic core and a shell having short range ferromagnetic correlation between the uncompensated surface spins in nanoscale regime. The ferromagnetic fractions obtained theoretically in the nanoparticles has been shown to be in the good agreement with the experimental results. The method of several orders of magnitude improvement of the magnetoresistive property will have enormous potential for magnetic field sensor technology. PMID:26837285

In situ deposition of poly(1,8-diaminonaphthalene): from thin films to nanometer-sized structures

International Nuclear Information System (INIS)

Tagowska, Magdalena; PaIys, Barbara; Mazur, Maciej; Skompska, Magdalena; Jackowska, Krystyna

2005-01-01

Chemical in situ deposition of poly(1,8-diaminonaphthalene) (p(1,8-DAN)) on conductive supports in aqueous and acetonitrile solutions was investigated using electrochemical quartz crystal microbalance (EQCM) and UV-vis spectroscopy. The resulting deposits were examined by the means of cyclic voltammetry (CV), FT-IR and Raman spectroscopy. P(1,8-DAN) was also deposited via chemical polymerization onto a porous polycarbonate membrane (PC) which served as a template for synthesis of nanometer-sized structures. The deposits of p(1,8-DAN) on PC substrate were imaged by atomic force microscopy (AFM) and the nanostructures obtained by dissolution of the template were visualized by scanning electron microscopy (SEM). The EQCM and UV-vis studies indicated that the polymer is formed both on the surface of the substrate and in the bulk of the polymerization solution. However, polymerization of 1,8-DAN in solution is delayed in comparison with deposition on the substrate. Electrochemical and spectroscopic properties of p(1,8-DAN) formed chemically closely resemble the properties of the electrosynthesized polymer. Furthermore, SEM images of p(1,8-DAN) nanostructures revealed that the polymer nanowires are formed in aqueous solutions, whereas two types of structures: nanowires and round shaped structures, not fitting to the pore size, can be obtained by chemical polymerization in the acetonitrile medium

Fluorescent gel particles in the nanometer range for detection of metabolites in living cells

DEFF Research Database (Denmark)

Almdal, K.; Sun, H.; Poulsen, A.K.

2006-01-01

micelles in oil microemulsions. Typical sizes of the particles are tens of nanometers. Characterization methods for such particles based on size exclusion chromatography, photon correlation spectroscopy, scanning electron microscopy, and atomic force microscopy have been developed. The stability...

Nanometer-Scale Pore Characteristics of Lacustrine Shale, Songliao Basin, NE China.

Directory of Open Access Journals (Sweden)

Min Wang

Full Text Available In shale, liquid hydrocarbons are accumulated mainly in nanometer-scale pores or fractures, so the pore types and PSDs (pore size distributions play a major role in the shale oil occurrence (free or absorbed state, amount of oil, and flow features. The pore types and PSDs of marine shale have been well studied; however, research on lacustrine shale is rare, especially for shale in the oil generation window, although lacustrine shale is deposited widely around the world. To investigate the relationship between nanometer-scale pores and oil occurrence in the lacustrine shale, 10 lacustrine shale core samples from Songliao Basin, NE China were analyzed. Analyses of these samples included geochemical measurements, SEM (scanning electron microscope observations, low pressure CO2 and N2 adsorption, and high-pressure mercury injection experiments. Analysis results indicate that: (1 Pore types in the lacustrine shale include inter-matrix pores, intergranular pores, organic matter pores, and dissolution pores, and these pores are dominated by mesopores and micropores; (2 There is no apparent correlation between pore volumes and clay content, however, a weak negative correlation is present between total pore volume and carbonate content; (3 Pores in lacustrine shale are well developed when the organic matter maturity (Ro is >1.0% and the pore volume is positively correlated with the TOC (total organic carbon content. The statistical results suggest that oil in lacustrine shale mainly occurs in pores with diameters larger than 40 nm. However, more research is needed to determine whether this minimum pore diameter for oil occurrence in lacustrine shale is widely applicable.

Half-heusler alloys with enhanced figure of merit and methods of making

Science.gov (United States)

Ren, Zhifeng; Yan, Xiao; Joshi, Giri; Chen, Shuo; Chen, Gang; Poudel, Bed; Caylor, James Christopher

2015-06-02

Thermoelectric materials and methods of making thermoelectric materials having a nanometer mean grain size less than 1 micron. The method includes combining and arc melting constituent elements of the thermoelectric material to form a liquid alloy of the thermoelectric material and casting the liquid alloy of the thermoelectric material to form a solid casting of the thermoelectric material. The method also includes ball milling the solid casting of the thermoelectric material into nanometer mean size particles and sintering the nanometer size particles to form the thermoelectric material having nanometer scale mean grain size.

Experimental equivalent cluster-size distributions in nano-metric volumes of liquid water

International Nuclear Information System (INIS)

Grosswendt, B.; De Nardo, L.; Colautti, P.; Pszona, S.; Conte, V.; Tornielli, G.

2004-01-01

Ionisation cluster-size distributions in nano-metric volumes of liquid water were determined for alpha particles at 4.6 and 5.4 MeV by measuring cluster-size frequencies in small gaseous volumes of nitrogen or propane at low gas pressure as well as by applying a suitable scaling procedure. This scaling procedure was based on the mean free ionisation lengths of alpha particles in water and in the gases measured. For validation, the measurements of cluster sizes in gaseous volumes and the cluster-size formation in volumes of liquid water of equivalent size were simulated by Monte Carlo methods. The experimental water-equivalent cluster-size distributions in nitrogen and propane are compared with those in liquid water and show that cluster-size formation by alpha particles in nitrogen or propane can directly be related to those in liquid water. (authors)

Liquidity Determinants of the Selected Banking Sectors and their Size Groups

Directory of Open Access Journals (Sweden)

Jana Laštůvková

2016-01-01

Full Text Available The article focuses on the factors affecting the liquidity of selected bank sectors, as well as their size groups, using panel regression analysis. For higher complexity of the results, multiple dependent variables are used: liquidity creation, outflow and net change. The values are calculated based on the specific method of liquidity risk measurement – gross liquidity flows. The results indicate both multiple effects of some factors on the given variables, as well as isolated influence of factors on a single liquidity form or size group. Thus, when looking for determinants using just one form of liquidity, such as creation, the results need not necessarily comprehensively show the influence of the given factors, and can lead to erroneous conclusions. The results also point to the differing behaviours of the size groups and their different sensitivity on the factors; smaller banks have shown higher sensitivity on macroeconomic variables. Higher flexibility in regulation could lead to higher optimization.

Universal liquid-phase laser fabrication of various nano-metals encapsulated by ultrathin carbon shells for deep-UV plasmonics.

Science.gov (United States)

Yu, Miao; Yang, Chao; Li, Xiao-Ming; Lei, Tian-Yu; Sun, Hao-Xuan; Dai, Li-Ping; Gu, Yu; Ning, Xue; Zhou, Ting; Wang, Chao; Zeng, Hai-Bo; Xiong, Jie

2017-06-29

The exploration of localized surface plasmon resonance (LSPR) beyond the usual visible waveband, for example within the ultraviolet (UV) or deep-ultraviolet (D-UV) regions, is of great significance due to its unique applications in secret communications and optics. However, it is still challenging to universally synthesize the corresponding metal nanostructures due to their high activity. Herein, we report a universal, eco-friendly, facile and rapid synthesis of various nano-metals encapsulated by ultrathin carbon shells, significantly with a remarkable deep-UV LSPR characteristic, via a liquid-phase laser fabrication method. Firstly, a new generation of the laser ablation in liquid (LAL) method has been developed with an emphasis on the elaborate selection of solvents to generate ultrathin carbon shells, and hence to stabilize the formed metal nanocrystals. As a result, a series of metal@carbon nanoparticles (NPs), including Cr@C, Ti@C, Fe@C, V@C, Al@C, Sn@C, Mn@C and Pd@C, can be fabricated by this modified LAL method. Interestingly, these NPs exhibit LSPR peaks in the range of 200-330 nm, which are very rare for localized surface plasmon resonance. Consequently, the UV plasmonic effects of these metal@carbon NPs were demonstrated both by the observed enhancement in UV photoluminescence (PL) from the carbon nanoshells and by the improvement of the photo-responsivity of UV GaN photodetectors. This work could provide a universal method for carbon shelled metal NPs and expand plasmonics into the D-UV waveband.

Passive micromechanical tags. An investigation into writing information at nanometer resolution on micrometer size objects

Energy Technology Data Exchange (ETDEWEB)

Schmieder, R.W.; Bastasz, R.J.

1995-01-01

The authors have completed a 3-year study of the technology related to the development of micron-sized passive micromechanical tags. The project was motivated by the discovery in 1990 by the present authors that low energy, high charge state ions (e.g., Xe{sup +44}) can produce nanometer-size damage sites on solid surfaces, and the realization that a pattern of these sites represents information. It was envisioned that extremely small, chemically inert, mechanical tags carrying a large label could be fabricated for a variety of applications, including tracking of controlled substances, document verification, process control, research, and engineering. Potential applications exist in the data storage, chemical, food, security, and other industries. The goals of this project were fully accomplished, and they are fully documented here. The work was both experimental and developmental. Most of the experimental effort was a search for appropriate tag materials. Several good materials were found, and the upper limits of information density were determined (ca. 10{sup 12} bit/cm{sup 2}). Most of the developmental work involved inventing systems and strategies for using these tags, and compiling available technologies for implementing them. The technology provided herein is application-specific: first, the application must be specified, then the tag can be developed for it. The project was not intended to develop a single tag for a single application or for all possible applications. Rather, it was meant to provide the enabling technology for fabricating tags for a range of applications. The results of this project provide sufficient information to proceed directly with such development.

Passive micromechanical tags. An investigation into writing information at nanometer resolution on micrometer size objects

International Nuclear Information System (INIS)

Schmieder, R.W.; Bastasz, R.J.

1995-01-01

The authors have completed a 3-year study of the technology related to the development of micron-sized passive micromechanical tags. The project was motivated by the discovery in 1990 by the present authors that low energy, high charge state ions (e.g., Xe +44 ) can produce nanometer-size damage sites on solid surfaces, and the realization that a pattern of these sites represents information. It was envisioned that extremely small, chemically inert, mechanical tags carrying a large label could be fabricated for a variety of applications, including tracking of controlled substances, document verification, process control, research, and engineering. Potential applications exist in the data storage, chemical, food, security, and other industries. The goals of this project were fully accomplished, and they are fully documented here. The work was both experimental and developmental. Most of the experimental effort was a search for appropriate tag materials. Several good materials were found, and the upper limits of information density were determined (ca. 10 12 bit/cm 2 ). Most of the developmental work involved inventing systems and strategies for using these tags, and compiling available technologies for implementing them. The technology provided herein is application-specific: first, the application must be specified, then the tag can be developed for it. The project was not intended to develop a single tag for a single application or for all possible applications. Rather, it was meant to provide the enabling technology for fabricating tags for a range of applications. The results of this project provide sufficient information to proceed directly with such development

Finite size melting of spherical solid-liquid aluminium interfaces

DEFF Research Database (Denmark)

Chang, J.; Johnson, Erik; Sakai, T.

2009-01-01

We have investigated the melting of nano-sized cone shaped aluminium needles coated with amorphous carbon using transmission electron microscopy. The interface between solid and liquid aluminium was found to have spherical topology. For needles with fixed apex angle, the depressed melting tempera...... to the conclusion that the depressed melting temperature is not controlled solely by the inverse radius 1/R. Instead, we found a direct relation between the depressed melting temperature and the ratio between the solid-liquid interface area and the molten volume.......We have investigated the melting of nano-sized cone shaped aluminium needles coated with amorphous carbon using transmission electron microscopy. The interface between solid and liquid aluminium was found to have spherical topology. For needles with fixed apex angle, the depressed melting...

Preparation of a nickel nanopowder by wire explosion in liquid media

International Nuclear Information System (INIS)

Cho, Chuhyun; Ha, Yooncheol; Kang, Chungil; Jin, Yunsik; Rim, Geunhie

2010-01-01

Nickel wires of 0.8 mm in diameter and 80 mm in length were electrically exploded in liquid media, such as water, ethyl alcohol, isopropyl alcohol, and acetone. The electrical energy discharged through the wire was 10 kJ. The distribution of particle sizes was broad from a few μm to tens of nanometer, regardless of the liquid medium used in this study. The particles could be classified according to their sizes by using a centrifugal separator. The powder prepared in distilled water showed mainly a pure metallic Ni phase although a little oxide phase was observed in the XRD analysis. However, the powders prepared in ethyl alcohol, isopropyl alcohol, and acetone showed complicated unknown phases, which is attributed to a compound of carbon in the organic liquid. The unknown phase was turned into a pure metallic Ni phase after heat treatment at 400 .deg. C.

KINOFORM LENSES - TOWARD NANOMETER RESOLUTION.

Energy Technology Data Exchange (ETDEWEB)

STEIN, A.; EVANS-LUTTERODT, K.; TAYLOR, A.

2004-10-23

While hard x-rays have wavelengths in the nanometer and sub-nanometer range, the ability to focus them is limited by the quality of sources and optics, and not by the wavelength. A few options, including reflective (mirrors), diffractive (zone plates) and refractive (CRL's) are available, each with their own limitations. Here we present our work with kinoform lenses which are refractive lenses with all material causing redundant 2{pi} phase shifts removed to reduce the absorption problems inherently limiting the resolution of refractive lenses. By stacking kinoform lenses together, the effective numerical aperture, and thus the focusing resolution, can be increased. The present status of kinoform lens fabrication and testing at Brookhaven is presented as well as future plans toward achieving nanometer resolution.

Optoelectronic circuits in nanometer CMOS technology

CERN Document Server

Atef, Mohamed

2016-01-01

This book describes the newest implementations of integrated photodiodes fabricated in nanometer standard CMOS technologies. It also includes the required fundamentals, the state-of-the-art, and the design of high-performance laser drivers, transimpedance amplifiers, equalizers, and limiting amplifiers fabricated in nanometer CMOS technologies. This book shows the newest results for the performance of integrated optical receivers, laser drivers, modulator drivers and optical sensors in nanometer standard CMOS technologies. Nanometer CMOS technologies rapidly advanced, enabling the implementation of integrated optical receivers for high data rates of several Giga-bits per second and of high-pixel count optical imagers and sensors. In particular, low cost silicon CMOS optoelectronic integrated circuits became very attractive because they can be extensively applied to short-distance optical communications, such as local area network, chip-to-chip and board-to-board interconnects as well as to imaging and medical...

[Study of relationship between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite powder].

Science.gov (United States)

Chai, Feng; Xu, Ling; Liao, Yun-mao; Chao, Yong-lie

2003-07-01

The fabrication of all-ceramic dental restorations is challenged by ceramics' relatively low flexural strength and intrinsic poor resistance to fracture. This paper aimed at investigating the relationships between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite (Al(2)O(3)-nZrO(2)). Al(2)O(3)-nZrO(2) ceramics powder (W) was processed by combination methods of chemical co-precipitation and ball milling with addition of different powder-sized ZrO(2). Field-emission scanning electron microscopy was used to determine the particle size distribution and characterize the particle morphology of powders. The matrix compacts were made by slip-casting technique and sintered to 1,450 degrees C and flexural strength and the fracture toughness of them were measured. 1. The particle distribution of Al(2)O(3)-nZrO(2) ceramics powder ranges from 0.02 - 3.5 micro m and among them the superfine particles almost accounted for 20%. 2. The ceramic matrix samples with addition of nZrO(2) (W) showed much higher flexural strength (115.434 +/- 5.319) MPa and fracture toughness (2.04 +/- 0.10) MPa m(1/2) than those of pure Al(2)O(3) ceramics (62.763 +/- 7.220 MPa; 1.16 +/- 0.02 MPa m(1/2)). The particle size of additive ZrO(2) may impose influences on mechanical properties of Al(2)O(3)-nZrO(2) ceramics matrix. Good homogeneity and reasonable powder-size gradation of ceramic powder can improve the mechanical properties of material.

On-Chip Production of Size-Controllable Liquid Metal Microdroplets Using Acoustic Waves.

Science.gov (United States)

Tang, Shi-Yang; Ayan, Bugra; Nama, Nitesh; Bian, Yusheng; Lata, James P; Guo, Xiasheng; Huang, Tony Jun

2016-07-01

Micro- to nanosized droplets of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, have been used for developing a variety of applications in flexible electronics, sensors, catalysts, and drug delivery systems. Currently used methods for producing micro- to nanosized droplets of such liquid metals possess one or several drawbacks, including the lack in ability to control the size of the produced droplets, mass produce droplets, produce smaller droplet sizes, and miniaturize the system. Here, a novel method is introduced using acoustic wave-induced forces for on-chip production of EGaIn liquid-metal microdroplets with controllable size. The size distribution of liquid metal microdroplets is tuned by controlling the interfacial tension of the metal using either electrochemistry or electrocapillarity in the acoustic field. The developed platform is then used for heavy metal ion detection utilizing the produced liquid metal microdroplets as the working electrode. It is also demonstrated that a significant enhancement of the sensing performance is achieved by introducing acoustic streaming during the electrochemical experiments. The demonstrated technique can be used for developing liquid-metal-based systems for a wide range of applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Size and liquidity effects in Nigeria: an industrial sector study

OpenAIRE

Hearn, Bruce

2013-01-01

This study estimates liquidity premiums using the recently developed Liu (2006) measure within a multifactor capital asset pricing model (CAPM) including size premiums and a time varying parameter model for the West African emerging market of Nigeria. The evidence suggests that liquidity factors are relevant only for financial and basic materials sector stocks while size factor is more generally relevant in explaining the cross section of stock returns in the Nigerian domestic equity market....

Simple and rapid spectrophotometric determination of trace titanium (IV) enriched by nanometer size zirconium dioxide in natural water

International Nuclear Information System (INIS)

Zheng Fengying; Li Shunxing; Lin Luxiu; Cheng Liqing

2009-01-01

A novel method for preconcentration of Ti(IV) with nanometer size ZrO 2 and determination by spectrophotometry has been developed. Ti(IV) was selectively adsorbed on 300 mg ZrO 2 from 500 mL solution at pH 6.0, then eluted by 5 mL 11.3 mol L -1 HF. The eluent added was diantipyrylmethane (DAPM, as chromogenic reagent) and ascorbic acid (as masking agent), used for the analysis of Ti(IV) by measuring the absorbance at 390 nm with spectrophotometry, based on the chromogenic reaction between the Ti(IV) and DAPM. This method gave a concentration enhancement of 100 for 500 mL sample, eliminated the sizable interferences on direct determination with spectrophotometry. Detection limit (3σ, n = 11) of 0.1 μg L -1 was obtained. The method was applied to determine the concentration of Ti(IV) in river water and seawater and the analytical recoveries of Ti(IV) added to samples were 97.6-101.3%.

Droplet-Sizing Liquid Water Content Sensor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Icing is one of the most significant hazards to aircraft. A sizing supercooled liquid water content (SSLWC) sonde is being developed to meet a directly related need...

Influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces

International Nuclear Information System (INIS)

Bresme, Fernando; Gonzalez-Melchor, Minerva; Alejandre, Jose

2005-01-01

The influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces is investigated using molecular dynamics simulations of the soft primitive model. Ion size asymmetry results in charge separation at the liquid-vapour interface and therefore in a local violation of the electroneutrality condition. For moderate size asymmetries the electrostatic potential at the interface can reach values of the order of 0.1 V. Size asymmetry plays a very important role in determining ion adsorption at the liquid-vapour interface of ionic mixtures. The interfacial adsorption of the bigger component results in an increase of the electrostatic potential, and a reduction of the interfacial surface tension. Our results show that ionic mixtures provide a very efficient way to tune the electrostatics and surface properties of ionic liquid-vapour interfaces

Influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces

Energy Technology Data Exchange (ETDEWEB)

Bresme, Fernando [Department of Chemistry, Imperial College London, London SW7 2AZ (United Kingdom); Gonzalez-Melchor, Minerva [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco 186, Colonia Vicentina, 09340 Mexico D.F. (Mexico); Alejandre, Jose [Departamento de QuImica, Universidad Autonoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco 186, Colonia Vicentina, 09340 Mexico D.F. (Mexico)

2005-11-16

The influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces is investigated using molecular dynamics simulations of the soft primitive model. Ion size asymmetry results in charge separation at the liquid-vapour interface and therefore in a local violation of the electroneutrality condition. For moderate size asymmetries the electrostatic potential at the interface can reach values of the order of 0.1 V. Size asymmetry plays a very important role in determining ion adsorption at the liquid-vapour interface of ionic mixtures. The interfacial adsorption of the bigger component results in an increase of the electrostatic potential, and a reduction of the interfacial surface tension. Our results show that ionic mixtures provide a very efficient way to tune the electrostatics and surface properties of ionic liquid-vapour interfaces.

Wetting at the nanometer scale: effects of long-range forces and substrate heterogeneities

International Nuclear Information System (INIS)

Checco, Antonio

2003-01-01

Wetting phenomena on the nano-scale remain poorly understood in spite of their growing theoretical and practical interest. In this context, the present work aimed at studying partial wetting of nanometer-sized alkane droplets on 'model' surfaces build by self-assembly of organic monolayers. For this purpose a novel technique, based on 'noncontact' Atomic Force Microscopy (AFM), has been developed to image, with minimal artefacts, drops of adjustable size directly condensed on so- lid surfaces. We have thus shown that contact angle of alkanes, wetting a weakly heterogeneous, silanized substrate, noticeably decreases from its macroscopic value for droplets sizes in the submicron range. The line tension, arising in this case from purely dispersive long-range interactions between the liquid and the substrate, is theoretically too weak to be responsible for the observed effect. Therefore we have supposed that contact angle is affected by mesoscopic chemical heterogeneities of the substrate whenever the droplets size becomes sufficiently small. This scenario has been supported by numerical simulations based on a simplified model of the spatial distribution of surface defects. Similar experiments, performed on different substrates (monolayers made of alkane-thiols self-assembled on gold and of alkyl chains covalently bound onto a silicon surface), have also shown that wetting on small scales is strongly affected by minimal physical and chemical surface heterogeneities. Finally, to provide further examples of the potential of the above mentioned AFM technique, we have studied the wettability of nano-structured surfaces and the local wetting properties of hair. (author) [fr

Nanometer Characterization/Manipulation Facility

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: Characterizes the nanometer scale of biological, chemical, physical, electronic, and mechanical properties of surfaces and thin films using scanning probe...

Ultrahigh-power supercapacitors based on highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon frameworks.

Science.gov (United States)

Yan, Pengtao; Zhang, Xuesha; Hou, Meiling; Liu, Yanyan; Liu, Ting; Liu, Kang; Zhang, Ruijun

2018-06-22

In order to develop energy storage devices with high power performance, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate a highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon framework (hcGNS/nCDC). In this architecture, nCDC possesses short transport paths for electrolyte ions, thus ensuring the rapid ions transportation. The excellent electrical conductivity of hcGNS can reduce the electrode internal resistance for the supercapacitor and thus endows the hcGNS/nCDC composite electrodes with excellent electronic transportation performance. Electrochemical measurements show that the cyclic voltammogram of hcGNS/nCDC can maintain a rectangular-like shape with the increase of the scan rate from 5 mV s -1 to 20 V s -1 , and the specific capacitance retention is up to 51% even at a high scan rate of 20 V s -1 , suggesting ultrahigh power performance, which, to the best of our knowledge, is among the best power performances reported so far for the carbon materials. Furthermore, the hcGNS/nCDC composite also shows an excellent cycling stability (no drop in its capacitance occurs even after 10000 cycles). This work demonstrates the advantage in the ultrahigh power performance for the framework having both short transport pathways for electrolyte ions and high electrical conductivity.

Ultrahigh-power supercapacitors based on highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon frameworks

Science.gov (United States)

Yan, Pengtao; Zhang, Xuesha; Hou, Meiling; Liu, Yanyan; Liu, Ting; Liu, Kang; Zhang, Ruijun

2018-06-01

In order to develop energy storage devices with high power performance, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate a highly conductive graphene nanosheet/nanometer-sized carbide-derived carbon framework (hcGNS/nCDC). In this architecture, nCDC possesses short transport paths for electrolyte ions, thus ensuring the rapid ions transportation. The excellent electrical conductivity of hcGNS can reduce the electrode internal resistance for the supercapacitor and thus endows the hcGNS/nCDC composite electrodes with excellent electronic transportation performance. Electrochemical measurements show that the cyclic voltammogram of hcGNS/nCDC can maintain a rectangular-like shape with the increase of the scan rate from 5 mV s‑1 to 20 V s‑1, and the specific capacitance retention is up to 51% even at a high scan rate of 20 V s‑1, suggesting ultrahigh power performance, which, to the best of our knowledge, is among the best power performances reported so far for the carbon materials. Furthermore, the hcGNS/nCDC composite also shows an excellent cycling stability (no drop in its capacitance occurs even after 10000 cycles). This work demonstrates the advantage in the ultrahigh power performance for the framework having both short transport pathways for electrolyte ions and high electrical conductivity.

Invariance of the solid-liquid interfacial energy in electrowetting probed via capillary condensation.

Science.gov (United States)

Gupta, Rohini; Olivier, Gloria K; Frechette, Joelle

2010-07-20

Capillary condensation is employed to probe the solid-liquid interfacial energy in electrowetting on dielectric. The height of an annular water meniscus formed via capillary condensation inside the surface force apparatus is measured as a function of the potential applied across the meniscus and the dielectric stack where the meniscus is formed. According to the Kelvin equation, a decrease in the solid-liquid interfacial energy at constant temperature and relative humidity should lead to an increase in the meniscus height. Our experimental results on nanometer-sized meniscus are in agreement with the work of Mugele [J. Phys.: Condens. Matter 2007, 19, 375112] and unequivocally demonstrate that the real contact angle (or the solid-liquid interfacial energy) remains unaltered in electrowetting on dielectric.

The Ages in a Self-Suspended Nanoparticle Liquid

KAUST Repository

Agarwal, Praveen

2010-01-13

Telomers ionically tethered to nanometer-sized particles yield self-suspended, nanoparticle-Iaden liquids with unusual dynamical features. By subjecting these suspensions to controlled, modest shear strains, we find that their flow behaviors observed using experiments performed on time scales of tens of seconds can be projected to obtain maps of their dynamical response on geological time scales. That such extraordinarily slow dynamic processes can be uncovered from real-time measurements by simply stretching a system provides a simple but powerful tool for interrogating extremely slow motions in other jammed physical states. © 2010 American Chemical Society.

Study on chemical reactivity control of liquid sodium. Research program

International Nuclear Information System (INIS)

Saito, Jun-ichi; Ara, Kuniaki; Sugiyama, Ken-ichiro; Kitagawa, Hiroshi; Oka, Nobuki; Yoshioka, Naoki

2007-01-01

Liquid sodium has the excellent properties as coolant of the fast breeder reactor (FBR). On the other hand, it reacts high with water and oxygen. So an innovative technology to suppress the reactivity is desired. The purpose of this study is to control the chemical reactivity of liquid sodium by dispersing the nanometer-size metallic particles (we call them Nano-particles) into liquid sodium. We focus on the atomic interaction between Nano-particles and sodium atoms. And we try to apply it to suppress the chemical reactivity of liquid sodium. Liquid sodium dispersing Nano-particles is named 'Nano-fluid'. Research programs of this study are the Nano-particles production, the evaluation of reactivity suppression of liquid sodium and the feasibility study to FBR plant. In this paper, the research programs and status are described. The important factors for particle production were understood. In order to evaluate the chemical reactivity of Nano-fluid the research programs were planned. The feasibility of the application of Nano-fluid to the coolant of FBR plant was evaluated preliminarily from the viewpoint of design and operation. (author)

Improved Root Normal Size Distributions for Liquid Atomization

Science.gov (United States)

2015-11-01

ANSI Std. Z39.18 j CONVERSION TABLE Conversion Factors for U.S. Customary to metric (SI) units of measurement. MULTIPLY BY TO...Gray (Gy) coulomb /kilogram (C/kg) second (s) kilogram (kg) kilo pascal (kPa) 1 Improved Root Normal Size Distributions for Liquid

Glass ceramic ZERODUR enabling nanometer precision

Science.gov (United States)

Jedamzik, Ralf; Kunisch, Clemens; Nieder, Johannes; Westerhoff, Thomas

2014-03-01

The IC Lithography roadmap foresees manufacturing of devices with critical dimension of digit nanometer asking for nanometer positioning accuracy requiring sub nanometer position measurement accuracy. The glass ceramic ZERODUR® is a well-established material in critical components of microlithography wafer stepper and offered with an extremely low coefficient of thermal expansion (CTE), the tightest tolerance available on market. SCHOTT is continuously improving manufacturing processes and it's method to measure and characterize the CTE behavior of ZERODUR® to full fill the ever tighter CTE specification for wafer stepper components. In this paper we present the ZERODUR® Lithography Roadmap on the CTE metrology and tolerance. Additionally, simulation calculations based on a physical model are presented predicting the long term CTE behavior of ZERODUR® components to optimize dimensional stability of precision positioning devices. CTE data of several low thermal expansion materials are compared regarding their temperature dependence between - 50°C and + 100°C. ZERODUR® TAILORED 22°C is full filling the tight CTE tolerance of +/- 10 ppb / K within the broadest temperature interval compared to all other materials of this investigation. The data presented in this paper explicitly demonstrates the capability of ZERODUR® to enable the nanometer precision required for future generation of lithography equipment and processes.

Computational analysis of the atomic size effect in bulk metallic glasses and their liquid precursors

International Nuclear Information System (INIS)

Kokotin, V.; Hermann, H.

2008-01-01

The atomic size effect and its consequences for the ability of multicomponent liquid alloys to form bulk metallic glasses are analyzed in terms of the generalized Bernal's model for liquids, following the hypothesis that maximum density in the liquid state improves the glass-forming ability. The maximum density that can be achieved in the liquid state is studied in the 2(N-1) dimensional parameter space of N-component systems. Computer simulations reveal that the size ratio of largest to smallest atoms are most relevant for achieving the maximum packing for N = 3-5, whereas the number of components plays a minor role. At small size ratio, the maximum packing density can be achieved by different atomic size distributions, whereas for medium size ratios the maximum density is always correlated to a concave size distribution. The relationship of the results to Miracle's efficient cluster packing model is also discussed

Track structure of protons and other light ions in liquid water: applications of the LIonTrack code at the nanometer scale.

Science.gov (United States)

Bäckström, G; Galassi, M E; Tilly, N; Ahnesjö, A; Fernández-Varea, J M

2013-06-01

The LIonTrack (Light Ion Track) Monte Carlo (MC) code for the simulation of H(+), He(2+), and other light ions in liquid water is presented together with the results of a novel investigation of energy-deposition site properties from single ion tracks. The continuum distorted-wave formalism with the eikonal initial state approximation (CDW-EIS) is employed to generate the initial energy and angle of the electrons emitted in ionizing collisions of the ions with H2O molecules. The model of Dingfelder et al. ["Electron inelastic-scattering cross sections in liquid water," Radiat. Phys. Chem. 53, 1-18 (1998); "Comparisons of calculations with PARTRAC and NOREC: Transport of electrons in liquid water," Radiat. Res. 169, 584-594 (2008)] is linked to the general-purpose MC code PENELOPE/penEasy to simulate the inelastic interactions of the secondary electrons in liquid water. In this way, the extended PENELOPE/penEasy code may provide an improved description of the 3D distribution of energy deposits (EDs), making it suitable for applications at the micrometer and nanometer scales. Single-ionization cross sections calculated with the ab initio CDW-EIS formalism are compared to available experimental values, some of them reported very recently, and the theoretical electronic stopping powers are benchmarked against those recommended by the ICRU. The authors also analyze distinct aspects of the spatial patterns of EDs, such as the frequency of nearest-neighbor distances for various radiation qualities, and the variation of the mean specific energy imparted in nanoscopic targets located around the track. For 1 MeV/u particles, the C(6+) ions generate about 15 times more clusters of six EDs within an ED distance of 3 nm than H(+). On average clusters of two to three EDs for 1 MeV/u H(+) and clusters of four to five EDs for 1 MeV/u C(6+) could be expected for a modeling double strand break distance of 3.4 nm.

Sensitive SERS detection at the single-particle level based on nanometer-separated mushroom-shaped plasmonic dimers

Science.gov (United States)

Xiang, Quan; Li, Zhiqin; Zheng, Mengjie; Liu, Qing; Chen, Yiqin; Yang, Lan; Jiang, Tian; Duan, Huigao

2018-03-01

Elevated metallic nanostructures with nanogaps (film deposition. By controlling the initial size of nanogaps in resist structures and the following deposited film thickness, metallic nanogaps could be tuned at the sub-10 nm scale with single-digit nanometer precision. Both experimental and simulated results revealed that gold dimer on mushroom-shaped pillars have the capability to achieve higher SERS enhancement factor comparing to those plasmonic dimers on cylindrical pillars or on a common SiO2/Si substrate, implying that the nanometer-gapped elevated dimer is an ideal platform to achieve the highest possible field enhancement for various plasmonic applications.

The structure of the solid-liquid interface: atomic size effect

International Nuclear Information System (INIS)

Geysermans, P.; Pontikis, V.

2002-01-01

The atomic structure of the solid-liquid heterophase interface was investigated by using molecular dynamics. Two kinds of systems were studied; the first one was crystalline copper with (100) and (111) surface terminations in contact with liquid aluminium, while in the second one the interface was modelled by two systems in contact made of Lennard-Jones particles with different size (σ) and energy (ε) parameters. We found that at the interface the liquid was layered whatever the crystallographic orientation of the surface. The layering of the liquid is still preserved when the ratio of particles sites (χ=σ 1 /σ 2 ) changes while an epitaxial relationship is always found between the crystal and the first liquid layer. The average density of the latter is closely related to the χ value. (authors)

Electro-spray of high viscous liquids for producing mono-sized spherical alginate beads

Institute of Scientific and Technical Information of China (English)

Hamid Moghadam; Mohsen Samimi; Abdolreza Samimi; Mohamad Khorram

2008-01-01

Alginate beads, often used for controlled release of enzymes and drugs, are usually produced by spraying sodium alginate liquid into a gelling agent using mechanical vibration nozzle or air jet. In this work an alternative method of electro-spray was employed to form droplets with desired size from a highly viscous sodium alginate solution using constant DC voltage. The droplets were then cured in a calcium chloride solution. The main objective was to produce mono-sized beads from such a highly viscous and non-Newtonian liquid (1000-5000 mPa s). The effects of nozzle diameter, flow rate and concentration of liquid on the size of the beads were investigated. Among the parameters studied, voltage had a pronounced effect on the size of beads as compared to flow rate zzle diameter and concentration of alginate liquid. The size of beads was reduced to a minimum value with increasing the voltage in the range of 0-10 kV. At the early stages of voltage increase (I.e. Up to about 4 kV), the rate of size reduction was relatively low, while the dripping mode dominated. However, in the middle part of the range of applied voltage, where the rate of size reduction was high (I.e. About 4-7 kV), an unstable transition occurred between dripping and jetting. At the end part of the range (I.e. 7-10 kV) jet mode of spray was observed. Increasing the height of fall of the droplets was found to improve the sphericity of the beads, because of the increased time of flight for the droplets. This was especially identifiable at higher concentrations of the alginate liquid (I.e. 3 w/v%)

Sub-nanometer-resolution imaging of peptide nanotubes in water using frequency modulation atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Sugihara, Tomoki; Hayashi, Itsuho; Onishi, Hiroshi [Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501 (Japan); Kimura, Kenjiro, E-mail: kimura@gold.kobe-u.ac.jp [Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501 (Japan); Tamura, Atsuo [Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501 (Japan)

2013-06-20

Highlights: ► Peptide nanotubes were aligned on highly oriented pyrolytic graphite surface. ► We visualized sub-nanometer-scale structure on peptide nanotube surface in water. ► We observed hydration structure at a peptide nanotube/water interface. - Abstract: Peptide nanotubes are self-assembled fibrous materials composed of cyclic polypeptides. Recently, various aspects of peptide nanotubes have been studied, in particular the utility of different methods for making peptide nanotubes with diverse designed functions. In order to investigate the relationship between formation, function and stability, it is essential to analyze the precise structure of peptide nanotubes. Atomic-scale surface imaging in liquids was recently achieved using frequency modulation atomic force microscopy with improved force sensing. Here we provide a precise surface structural analysis of peptide nanotubes in water without crystallizing them obtained by imaging the nanotubes at the sub-nanometer scale in water. In addition, the local hydration structure around the peptide nanotubes was observed at the nanotube/water interface.

Continuous scanning of the mobility and size distribution of charged clusters and nanometer particles in atmospheric air and the Balanced Scanning Mobility Analyzer BSMA

Science.gov (United States)

Tammet, H.

2006-12-01

Measuring of charged nanometer particles in atmospheric air is a routine task in research on atmospheric electricity, where these particles are called the atmospheric ions. An aspiration condenser is the most popular instrument for measuring atmospheric ions. Continuous scanning of a mobility distribution is possible when the aspiration condenser is connected as an arm of a balanced bridge. Transfer function of an aspiration condenser is calculated according to the measurements of geometric dimensions, air flow rate, driving voltage, and electric current. The most complicated phase of the calibration is the estimation of the inlet loss of ions due to the Brownian deposition. The available models of ion deposition on the protective inlet screen and the inlet control electrofilter have the uncertainty of about 20%. To keep the uncertainty of measurements low the adsorption should not exceed a few tens of percent. The online conversion of the mobility distribution to the size distribution and a correct reduction of inlet losses are possible when air temperature and pressure are measured simultaneously with the mobility distribution. Two instruments called the Balanced Scanning Mobility Analyzers (BSMA) were manufactured and tested in routine atmospheric measurements. The concentration of atmospheric ions of the size of about a few nanometers is very low and a high air flow rate is required to collect enough of ion current. The air flow of 52 l/s exceeds the air flow in usual aerosol instruments by 2-3 orders of magnitude. The high flow rate reduces the time of ion passage to 60 ms and the heating of air in an analyzer to 0.2 K, which suppresses a possible transformation of ions inside the instrument. The mobility range of the BSMA of 0.032-3.2 cm 2 V - 1 s - 1 is logarithmically uniformly divided into 16 fractions. The size distribution is presented by 12 fractions in the diameter range of 0.4-7.5 nm. The measurement noise of a fraction concentration is typically

Nanometals - Status and perspective

International Nuclear Information System (INIS)

Faester, S.; Hansen, N.; Huang, X.; Juul Jensen, D.; Ralph, B.

2012-01-01

Nanometals and nanotechnology have over the years been covered in papers, books and conferences - also in many Risoe International Symposia, where the 30th in 2009 dealt solely with nanostructured metals. Since then, rapid progress has been made in synthesis, characterization and modeling, and it is timely to discuss status and perspective also with a view on applications in an international forum such as the Risoe Symposium. Both keynote and contributed papers address important current problems illustrating global research and development in this field. Examples are the development of new synthesis techniques followed by characterization and modeling of microstructures both in 2D and 3D now starting to bridge the micrometer scales. The vital area of mechanical behavior is addressed by the development of new testing techniques and a broad effort to characterize and model mechanical properties of metals strengthened by dislocations and twins. This research has now led to new understanding of both strengthening mechanisms and strengh structure relationships based on experiments in combination with analytical and numerical modeling. The holistic approach to research on nanometals demonstrated by these proceedings can guide both scientists and technologists in their future work also with the aim of introducing into society this new group of advanced materials. Such an effort is important, as science and technology today is significantly affected by politics of governments and international institutions, and therefore a new initiative in the pressent is to include a discussion of research and development in the area of nanometals i USA, China and Japan. (Author)

Nanometals - Status and perspective

Energy Technology Data Exchange (ETDEWEB)

Faester, S.; Hansen, N.; Huang, X.; Juul Jensen, D.; Ralph, B. (eds.)

2012-11-01

Nanometals and nanotechnology have over the years been covered in papers, books and conferences - also in many Risoe International Symposia, where the 30th in 2009 dealt solely with nanostructured metals. Since then, rapid progress has been made in synthesis, characterization and modeling, and it is timely to discuss status and perspective also with a view on applications in an international forum such as the Risoe Symposium. Both keynote and contributed papers address important current problems illustrating global research and development in this field. Examples are the development of new synthesis techniques followed by characterization and modeling of microstructures both in 2D and 3D now starting to bridge the micrometer scales. The vital area of mechanical behavior is addressed by the development of new testing techniques and a broad effort to characterize and model mechanical properties of metals strengthened by dislocations and twins. This research has now led to new understanding of both strengthening mechanisms and strengh structure relationships based on experiments in combination with analytical and numerical modeling. The holistic approach to research on nanometals demonstrated by these proceedings can guide both scientists and technologists in their future work also with the aim of introducing into society this new group of advanced materials. Such an effort is important, as science and technology today is significantly affected by politics of governments and international institutions, and therefore a new initiative in the pressent is to include a discussion of research and development in the area of nanometals i USA, China and Japan. (Author)

Dispersion effect and auto-reconditioning performance of nanometer ...

Indian Academy of Sciences (India)

This paper reported on dispersion effect and dispersing techniques of nanometer WS2 particles in the green lubricant concocted by us. And it also researched on auto-reconditioning performance of nanometer WS2 particles to the abrasive surfaces of steel ball from four-ball tribology test and piston ring from engine ...

Correlation between lateral size and gas sensing performance of MoSe2 nanosheets

Science.gov (United States)

Zhang, Shaolin; Nguyen, Thuy Hang; Zhang, Weibin; Park, Youngsin; Yang, Woochul

2017-10-01

We demonstrate a facile synthetic method to prepare lateral size controlled molybdenum diselenide (MoSe2) nanosheets using liquid phase exfoliated few-layer MoSe2 nanosheets as a starting material. By precisely controlling the centrifugation condition, preparation of MoSe2 nanosheets with a narrow size distribution ranging from several hundred nanometers to several micrometers could be realized. The accurate size control of MoSe2 nanosheets offers us a great opportunity to examine the size dependent sensing properties. The sensing test results demonstrate that the MoSe2 nanosheets provide competitive advantages compared with conventional graphene based sensors. A tradeoff phenomenon on sensing response and recovery as the lateral size of MoSe2 nanosheets varies is observed. First principles calculations reveal that the ratio of edge-surface sites is responsible for this phenomenon. The correlation between the lateral size and gas sensing performance of MoSe2 nanosheets is established.

Iterative inversion of phase-Doppler-anemometry size distributions from sprays of optically inhomogeneous liquids.

Science.gov (United States)

Köser, O; Wriedt, T

1996-05-20

Using phase Doppler anemometry (PDA) to investigate sprays of optically inhomogeneous liquids leads to blurred measured size distributions. The blurring function is formed by performance of PDA measurements on single-size droplets generated by a piezoelectric droplet generator. To obtain the undistorted droplet-size distributions, a constrained iterative inversion algorithm is applied. The number of iteration steps to achieve the best possible restoration is determined by the use of synthetically generated data that has noise properties similar to the measured histograms. The obtained size distributions are checked by comparison with undistorted measurement results of an atomized optical homogeneous liquid.

A scanning tunneling microscope with a scanning range from hundreds of micrometers down to nanometer resolution.

Science.gov (United States)

Kalkan, Fatih; Zaum, Christopher; Morgenstern, Karina

2012-10-01

A beetle type stage and a flexure scanning stage are combined to form a two stages scanning tunneling microscope (STM). It operates at room temperature in ultrahigh vacuum and is capable of scanning areas up to 300 μm × 450 μm down to resolution on the nanometer scale. This multi-scale STM has been designed and constructed in order to investigate prestructured metallic or semiconducting micro- and nano-structures in real space from atomic-sized structures up to the large-scale environment. The principle of the instrument is demonstrated on two different systems. Gallium nitride based micropillars demonstrate scan areas up to hundreds of micrometers; a Au(111) surface demonstrates nanometer resolution.

Nanometer-scale temperature measurements of phase change memory and carbon nanomaterials

Science.gov (United States)

Grosse, Kyle Lane

This work investigates nanometer-scale thermometry and thermal transport in new electronic devices to mitigate future electronic energy consumption. Nanometer-scale thermal transport is integral to electronic energy consumption and limits current electronic performance. New electronic devices are required to improve future electronic performance and energy consumption, but heat generation is not well understood in these new technologies. Thermal transport deviates significantly at the nanometer-scale from macroscopic systems as low dimensional materials, grain structure, interfaces, and thermoelectric effects can dominate electronic performance. This work develops and implements an atomic force microscopy (AFM) based nanometer-scale thermometry technique, known as scanning Joule expansion microscopy (SJEM), to measure nanometer-scale heat generation in new graphene and phase change memory (PCM) devices, which have potential to improve performance and energy consumption of future electronics. Nanometer-scale thermometry of chemical vapor deposition (CVD) grown graphene measured the heat generation at graphene wrinkles and grain boundaries (GBs). Graphene is an atomically-thin, two dimensional (2D) carbon material with promising applications in new electronic devices. Comparing measurements and predictions of CVD graphene heating predicted the resistivity, voltage drop, and temperature rise across the one dimensional (1D) GB defects. This work measured the nanometer-scale temperature rise of thin film Ge2Sb2Te5 (GST) based PCM due to Joule, thermoelectric, interface, and grain structure effects. PCM has potential to reduce energy consumption and improve performance of future electronic memory. A new nanometer-scale thermometry technique is developed for independent and direct observation of Joule and thermoelectric effects at the nanometer-scale, and the technique is demonstrated by SJEM measurements of GST devices. Uniform heating and GST properties are observed for

In-situ ionic liquid dispersive liquid-liquid microextraction using a new anion-exchange reagent combined Fe3O4 magnetic nanoparticles for determination of pyrethroid pesticides in water samples.

Science.gov (United States)

Fan, Chen; Liang, You; Dong, Hongqiang; Ding, Guanglong; Zhang, Wenbing; Tang, Gang; Yang, Jiale; Kong, Dandan; Wang, Deng; Cao, Yongsong

2017-07-04

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL -1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL -1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L -1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Photoinduced non-linear optical effects in the ZnS-Al, In-Sn doped film-glass nanometer-sized interfaces

International Nuclear Information System (INIS)

Kityk, I.V.; Makowska-Janusik, M.; Ebothe, J.; El Hichou, A.; El Idrissi, B.; Addou, M.

2002-01-01

The effective nanometer-sized thin layer (about 1-2 nm) located between a crystalline ZnS film and glass substrate is studied here using photoinduced optical and second-order non-linear optical (second harmonic generation (SHG) and electrooptics effects) techniques. A photoinduced shift of the effective energy gap is found for the first time in ZnS films doped with the same amount (4 at.%) of different elements, namely, In, Al and Sn. The photoinduced second-order non-linear optical properties (linear electrooptics (LEO) and SHG) of the specimens show a good correlation with the corresponding features of the linear optical susceptibilities, particularly, the imaginary part of dielectric susceptibility near the absorption edge. The maximal response of the photoinduced signal is observed for the pump-probe delaying time of about 20 ps. The performed experimental measurements indicate that the observed effects are stimulated by two factors: the first one is connected with the interface potential gradients at the glass-ZnS film boarder; the second one is a consequence of the additional polarization due to the insertion of Al, In and Sn atoms. The observed phenomenon may be proposed as a sensitive tool for investigation of thin semiconducting-glass interface layer. Moreover, such nanolayers may be applied in quantum electronic devices

Time evolution of the drop size distribution for liquid-liquid dispersion in an agitated tank

Czech Academy of Sciences Publication Activity Database

Šulc, R.; Kysela, Bohuš; Ditl, P.

2018-01-01

Roč. 72, č. 3 (2018), s. 543-553 ISSN 0366-6352 R&D Projects: GA ČR GA16-20175S Institutional support: RVO:67985874 Keywords : liquid–liquid dispersion * drop breakup * drop size distribution * time evolution Subject RIV: BK - Fluid Dynamics Impact factor: 1.258, year: 2016

Measuring adhesion on rough surfaces using atomic force microscopy with a liquid probe

Directory of Open Access Journals (Sweden)

Juan V. Escobar

2017-04-01

Full Text Available We present a procedure to perform and interpret pull-off force measurements during the jump-off-contact process between a liquid drop and rough surfaces using a conventional atomic force microscope. In this method, a micrometric liquid mercury drop is attached to an AFM tipless cantilever to measure the force required to pull this drop off a rough surface. We test the method with two surfaces: a square array of nanometer-sized peaks commonly used for the determination of AFM tip sharpness and a multi-scaled rough diamond surface containing sub-micrometer protrusions. Measurements are carried out in a nitrogen atmosphere to avoid water capillary interactions. We obtain information about the average force of adhesion between a single peak or protrusion and the liquid drop. This procedure could provide useful microscopic information to improve our understanding of wetting phenomena on rough surfaces.

Interparticle potential of 10 nanometer titanium nanoparticles in liquid sodium: Theoretical approach

Energy Technology Data Exchange (ETDEWEB)

Kim, Soo Jae; Park, Gun Yeop; Park, Hyun Sun; Baek, Je Hyun [POSTECH, Pohang (Korea, Republic of); Kim, Moo Hwan [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-10-15

A suspension of titanium nanoparticles (Ti NPs) in liquid sodium (Na) has been proposed as a method to mitigate the violent sodium-water reaction (SWR). The interparticle potential between Ti NPs in liquid Na may play a significant role in the agglomeration of NPs on the reaction surface and in the bulk liquid Na, since the potential contributes to a reduction in the long-term dispersion stability. For the effective control of the SWR with NPs, a physical understanding of the molecular dynamics of NPs in liquid Na is key. Therefore in this study, the nonretarded Van der Waals model and the solvation potential model are employed to analyze the interparticle potential. The ab initio calculation reveals that a strong repulsive force driven by the solvation potential exceeds the interparticle attraction and predicts the agglomeration energy required for two 10-nm Ti NPs to be 4 x 10{sup -17} J. The collision theory suggests that Ti NPs can be effective suppressors of the SWR due to the high energy barrier that prevents significant agglomeration of Ti NPs in quiescent liquid Na.

Why liquid displacement methods are sometimes wrong in estimating the pore-size distribution

NARCIS (Netherlands)

Gijsbertsen-Abrahamse, A.J.; Boom, R.M.; Padt, van der A.

2004-01-01

The liquid displacement method is a commonly used method to determine the pore size distribution of micro- and ultrafiltration membranes. One of the assumptions for the calculation of the pore sizes is that the pores are parallel and thus are not interconnected. To show that the estimated pore size

Effect of Pore Size on the Carbon Dioxide Adsorption Behavior of Porous Liquids Based on Hollow Silica.

Science.gov (United States)

Shi, Ting; Zheng, Yaping; Wang, Tianyu; Li, Peipei; Wang, Yudeng; Yao, Dongdong

2018-01-05

Porous liquids are an expanding class of material that has huge potential in gas separation and gas adsorption. Pore size has a dramatic influence on the gas adsorption of porous liquids. In this article, we chose hollow silica nanoparticles as cores, 3-(trihydroxysilyl)-1-propanesulfonic acid (SIT) as corona, and inexpensive industrial reagent polyether amine (M2070) as canopy to obtain a new type of porous liquids. Hollow silica nanospheres with different pore sizes were chosen to investigate the influence of porosity size on CO 2 adsorption capacity of porous liquids. Their chemical structure, morphology, thermal behavior and possible adsorption mechanism are discussed in detail. It was proved that with similar grafting density, porous liquid that has bigger pore size possesses a better CO 2 adsorption capacity (2.182 mmol g -1 under 2.5 MPa at 298 K). More than that, this article demonstrates a more facile and low-cost method to obtain porous liquids with good CO 2 adsorption capacity, recyclability, and huge variability. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mixed Surfactant Template Method for Preparation of Nanometer Selenium

Directory of Open Access Journals (Sweden)

Zhi-Lin Li

2009-01-01

Full Text Available Selenium nanoparticles have been synthesized in an aqueous solution by using sodium dodecyl sulfate and polyvinyl alcohol as a soft template. The factors on synthesis, such as reaction time, concentration of reactants and ultrasonic irradiation were studied. The uniform stable selenium nanospheres were obstained in the conditions of 1.0 (mass fraction sodium dodecyl sulfate, 1.0 (mass fraction polyvinyl alcohol, n(Vc:n(H2SeO3=7:1 and 7 minutes after the initiation of the reaction at room temperature. The average particle size of selenium is about 30 nm. The product was characterized by UV and TEM. Finally the applications of the red element nanometer selenium in anti-older cosmetics are presented.

Grinding model and material removal mechanism of medical nanometer zirconia ceramics.

Science.gov (United States)

Zhang, Dongkun; Li, Changhe; Jia, Dongzhou; Wang, Sheng; Li, Runze; Qi, Xiaoxiao

2014-01-01

Many patents have been devoted to developing medical nanometer zirconia ceramic grinding techniques that can significantly improve both workpiece surface integrity and grinding quality. Among these patents is a process for preparing ceramic dental implants with a surface for improving osseo-integration by sand abrasive finishing under a jet pressure of 1.5 bar to 8.0 bar and with a grain size of 30 µm to 250 µm. Compared with other materials, nano-zirconia ceramics exhibit unmatched biomedical performance and excellent mechanical properties as medical bone tissue and dentures. The removal mechanism of nano-zirconia materials includes brittle fracture and plastic removal. Brittle fracture involves crack formation, extension, peeling, and chipping to completely remove debris. Plastic removal is similar to chip formation in metal grinding, including rubbing, ploughing, and the formation of grinding debris. The materials are removed in shearing and chipping. During brittle fracture, the grinding-led transverse and radial extension of cracks further generate local peeling of blocks of the material. In material peeling and removal, the mechanical strength and surface quality of the workpiece are also greatly reduced because of crack extension. When grinding occurs in the plastic region, plastic removal is performed, and surface grinding does not generate grinding fissures and surface fracture, producing clinically satisfactory grinding quality. With certain grinding conditions, medical nanometer zirconia ceramics can be removed through plastic flow in ductile regime. In this study, we analyzed the critical conditions for the transfer of brittle and plastic removal in nano-zirconia ceramic grinding as well as the high-quality surface grinding of medical nanometer zirconia ceramics by ELID grinding.

Formation of polymer nanoparticles by UV pulsed laser ablation of poly (bisphenol A carbonate) in liquid environment

Science.gov (United States)

Martínez-Tong, Daniel E.; Sanz, Mikel; Ezquerra, Tiberio A.; Nogales, Aurora; Marco, José F.; Castillejo, Marta; Rebollar, Esther

2017-10-01

Suspensions of poly(bisphenol A carbonate) (PBAC) nanoparticles of varying size and shape have been produced by ablation of a PBAC target in liquid media with the fourth harmonic of a Q-switched Nd:YAG laser (wavelength 266 nm, full width at half maximum 4 ns, repetition rate 10 Hz). The polymer target was placed at the bottom of a rotating glass vessel filled with around a 10 mm column of liquid. Laser ablation in water leads to spherical nanoparticles with diameters of several tens of nanometers for fluences close to 1 J/cm2. Ablation at lower fluences, around 0.1 J/cm2, results in the production of nanoparticles of smaller diameters and also of non-spherical nanoparticles. Additional irradiations at the fluence of 0.1 J/cm2 were performed in several liquid media with different properties, in terms of density, viscosity, thermal conductivity, boiling temperature, isothermal compressibility and polarity. The different size distributions observed were related to the thermal conductivity of the systems, while their viscosity seems to be responsible for the development of nanostructures with different morphologies.

Energy harvesting from organic liquids in micro-sized microbial fuel cells

KAUST Repository

Mink, J.E.; Qaisi, R.M.; Logan, B.E.; Hussain, Muhammad Mustafa

2014-01-01

Micro-sized microbial fuel cells (MFCs) are miniature energy harvesters that use bacteria to convert biomass from liquids into usable power. The key challenge is transitioning laboratory test beds into devices capable of producing high power using

Gaining Control over Radiolytic Synthesis of Uniform Sub-3-nanometer Palladium Nanoparticles: Use of Aromatic Liquids in the Electron Microscope

Energy Technology Data Exchange (ETDEWEB)

Abellan Baeza, Patricia; Parent, Lucas R.; Al Hasan, Naila M.; Park, Chiwoo; Arslan, Ilke; Karim, Ayman M.; Evans, James E.; Browning, Nigel D.

2016-01-07

Synthesizing nanomaterials of uniform shape and size is of critical importance to access and manipulate the novel structure-property relationships arising at the nanoscale. In this work we synthesize Pd nanoparticles with well-controlled size using in situ liquid-stage scanning transmission electron microscopy (STEM) and demonstrate a match between the reaction kinetics and products of the radiolytic and chemical syntheses of size-stabilized Pd nanoparticles. We quantify the effect of electron dose on the nucleation kinetics, and compare these results with in situ small angle X-ray scattering (SAXS) experiments investigating the effect of temperature during chemical synthesis. This work introduces methods for precise control of nanoparticle synthesis in the STEM and provides a means to uncover the fundamental processes behind the size and shape stabilization of nanoparticles.

Atomistic Insight on the Charging Energetics in Sub-nanometer Pore Supercacitors

Energy Technology Data Exchange (ETDEWEB)

Qiao, Rui [ORNL; Huang, Jingsong [ORNL; Sumpter, Bobby G [ORNL; Meunier, Vincent [ORNL; Feng, Guang [Clemson University

2010-01-01

Electrodes featuring sub-nanometer pores can significantly enhance the capacitance and energy density of supercapacitors. However, ions must pay an energy penalty to enter sub-nanometer pores as they have to shed part of their solvation shell. The magnitude of such energy penalty plays a key role in determining the accessibility and charging/discharging of these sub-nanometer pores. Here we report on the atomistic simulation of Na+ and Cl ions entering a polarizable slit pore with a width of 0.82 nm. We show that the free energy penalty for these ions to enter the pore is less than 14 kJ/mol for both Na+ and Cl ions. The surprisingly small energy penalty is caused by the van der Waals attractions between ion and pore walls, the image charge effects, the moderate (19-26%) de-hydration of the ions inside the pore, and the strengthened interactions between ions and their hydration water molecules in the sub-nanometer pore. The results provide strong impetus for further developing nanoporous electrodes featuring sub- nanometer pores.

Mechanically activated self-propagated high-temperature synthesis of nanometer-structured MgB2

International Nuclear Information System (INIS)

Radev, D.D.; Marinov, M.; Tumbalev, V.; Radev, I.; Konstantinov, L.

2005-01-01

Nanometer-sized MgB 2 was prepared via a two-step modification of the mechanically activated self-propagated high-temperature synthesis. The experimental conditions and some structural and phase characteristics of the synthesized product are reported. It is shown that a single-phase material can be prepared after 2 h of intense mechanical treatment of the starting magnesium and boron powders and a synthesis induced at a current-pulse density of 30 A cm -2 . The average size of MgB 2 particles synthesized in this way is 70-80 nm. It is also shown that using the same reagents and the 'classic' high-temperature interaction at 850 deg C with a protective atmosphere of pure Ar, mean particle size of the MgB 2 obtained is 50 μm

Preparation of size-controlled magnetite nanoparticles with a graphene and polymeric ionic liquid coating for the quick, easy, cheap, effective, rugged and safe extraction of preservatives from vegetables.

Science.gov (United States)

Chen, Yaling; Cao, Shurui; Zhang, Lei; Xi, Cunxian; Li, Xianliang; Chen, Zhiqiong; Wang, Guoming

2016-05-27

Size-controlled magnetite nanoparticles (Fe3O4) with 200-1000nm were synthesized by co-precipitation method. Then Fe3O4@SiO2@G@PIL was synthesized and used as modified QuEChERS adsorbent for the determination of preservatives in vegetables. The size of about 200nm of Fe3O4 in Fe3O4@SiO2@G@PIL was selected as optimum size to clean-up. It not only exerted the nanometer features of magnetic nanoparticles, but also displayed the large specific surface area of graphene (G) and the solvent effects of polymeric ionic liquids (PILs). Various experimental parameters have been investigated. Under the optimized conditions, a simple, rapid and effective method for the determination of 20 preservatives residues in vegetables was established by modified QuEChERS to gas chromatography/mass spectrometry (GC-MS) analysis. The good linearity with correlation coefficients (R(2)) of 0.9972-0.9999 was obtained over the range of 0.02-2.00mg/L for 20 preservatives. The detection limits of the proposed method for 20 preservatives ranged from 0.82 to 6.64μg/kg. The adsorbent was successfully applied for extraction and determination of preservatives in vegetable samples, which thus was time-saving with keeping good clean-up performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Phase Behavior and Domain Size in Sphingomyelin-Containing Lipid Bilayers

Science.gov (United States)

Petruzielo, Robin S.; Heberle, Frederick A.; Drazba, Paul; Katsaras, John; Feigenson, Gerald W.

2013-01-01

Membrane raft size measurements are crucial to understanding the stability and functionality of rafts in cells. The challenge of accurately measuring raft size is evidenced by the disparate reports of domain sizes, which range from nanometers to microns for the ternary model membrane system sphingomyelin (SM)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/cholesterol (Chol). Using Förster resonance energy transfer (FRET) and differential scanning calorimetry (DSC), we established phase diagrams for porcine brain SM (bSM)/dioleoyl-sn-glycero-3-phosphocholine (DOPC)/Chol and bSM/POPC/Chol at 15 and 25°C. By combining two techniques with different spatial sensitivities, namely FRET and small-angle neutron scattering (SANS), we have significantly narrowed the uncertainty in domain size estimates for bSM/POPC/Chol mixtures. Compositional trends in FRET data revealed coexisting domains at 15 and 25°C for both mixtures, while SANS measurements detected no domain formation for bSM/POPC/Chol. Together these results indicate that liquid domains in bSM/POPC/Chol are between 2 and 7 nm in radius at 25°C: that is, domains must be on the order of the 2–6 nm Förster distance of the FRET probes, but smaller than the ~7 nm minimum cluster size detectable with SANS. However, for palmitoyl SM (PSM)/POPC/Chol at a similar composition, SANS detected coexisting liquid domains. This increase in domain size upon replacing the natural SM component (which consists of a mixture of chain lengths) with synthetic PSM, suggests a role for SM chain length in modulating raft size in vivo. PMID:23337475

THE FINANCIAL LIQUIDITY OF THE FOOD INDUSTRY ENTERPRISES IN POLAND IN THE SYSTEM SIZE OF ENTERPRISES

Directory of Open Access Journals (Sweden)

Anna Bieniasz

2013-12-01

Full Text Available The article presents the diversification of financial liquidity of food industry enterprises in Poland in 2009-2011 and indicates the main factors shaping liquidity. The study used unpublished data of Central Statistical Office, allowing for the analysis of liquidity in the system classes the food industry and the system enterprise size (small, medium, large. The analyses show, that the food industry in Poland in 2009-2011, regardless of their size and adopted ratios, have the ability to regulate the current liabilities, but kept at a low level. Analysis of the factors influencing liquidity showed, that the primary importance was turnover ratio of current liabilities, as well as ratio of financing of income through equity.

Phase diagram of nanoscale alloy particles used for vapor-liquid-solid growth of semiconductor nanowires.

Science.gov (United States)

Sutter, Eli; Sutter, Peter

2008-02-01

We use transmission electron microscopy observations to establish the parts of the phase diagram of nanometer sized Au-Ge alloy drops at the tips of Ge nanowires (NWs) that determine their temperature-dependent equilibrium composition and, hence, their exchange of semiconductor material with the NWs. We find that the phase diagram of the nanoscale drop deviates significantly from that of the bulk alloy, which explains discrepancies between actual growth results and predictions on the basis of the bulk-phase equilibria. Our findings provide the basis for tailoring vapor-liquid-solid growth to achieve complex one-dimensional materials geometries.

Characterization of Extracellular Vesicles by Size-Exclusion High-Performance Liquid Chromatography (HPLC).

Science.gov (United States)

Huang, Tao; He, Jiang

2017-01-01

Extracellular vesicles (EVs) have recently attracted substantial attention due to the potential diagnostic and therapeutic relevance. Although a variety of techniques have been used to isolate and analyze EVs, it is still far away from satisfaction. Size-exclusion chromatography (SEC), which separates subjects by size, has been widely applied in protein purification and analysis. The purpose of this chapter is to show the applications of size-exclusion high-performance liquid chromatography (HPLC) as methods for EV characterization of impurities or contaminants of small size, and thus for quality assay for the purity of the samples of EVs.

Size properties of colloidal nanoparticles produced by nanosecond pulsed laser ablation and studying the effects of liquid medium and laser fluence

International Nuclear Information System (INIS)

Mahdieh, Mohammad Hossein; Fattahi, Behzad

2015-01-01

Highlights: • Colloidal aluminum- and titanium-based nanoparticles fabricated by laser ablation. • Various liquid environments and laser fluences were applied as variable parameters. • Physical characteristics of liquid medium influence ablation process and nanoparticle formation. • Size properties of prepared nanoparticles depend on liquid medium and laser fluence. • Ablation of both metals in ethanol results in nanoparticles with smaller size. - Abstract: In this paper, pulsed laser ablation method was used for synthesis of colloidal nanoparticles of aluminum and titanium targets in distilled water, ethanol, and acetone as liquid environments. Ultraviolet–visible (UV–vis) absorption spectrophotometer and scanning electron microscope (SEM) were used for characterization of produced nanoparticles. Using image processing technique and analyzing the SEM images, nanoparticles’ mean size and size distribution were achieved. The results show that liquid medium has strong effect on size properties of produced nanoparticles. From the results, it was found that ablation of both metal targets in ethanol medium leads to formation of smaller size nanoparticles with narrower size distributions. The influence of laser fluence was also investigated. According to the results, higher laser fluence produces larger mean size nanoparticles with broader size distribution

Size properties of colloidal nanoparticles produced by nanosecond pulsed laser ablation and studying the effects of liquid medium and laser fluence

Energy Technology Data Exchange (ETDEWEB)

Mahdieh, Mohammad Hossein, E-mail: mahdm@iust.ac.ir; Fattahi, Behzad

2015-02-28

Highlights: • Colloidal aluminum- and titanium-based nanoparticles fabricated by laser ablation. • Various liquid environments and laser fluences were applied as variable parameters. • Physical characteristics of liquid medium influence ablation process and nanoparticle formation. • Size properties of prepared nanoparticles depend on liquid medium and laser fluence. • Ablation of both metals in ethanol results in nanoparticles with smaller size. - Abstract: In this paper, pulsed laser ablation method was used for synthesis of colloidal nanoparticles of aluminum and titanium targets in distilled water, ethanol, and acetone as liquid environments. Ultraviolet–visible (UV–vis) absorption spectrophotometer and scanning electron microscope (SEM) were used for characterization of produced nanoparticles. Using image processing technique and analyzing the SEM images, nanoparticles’ mean size and size distribution were achieved. The results show that liquid medium has strong effect on size properties of produced nanoparticles. From the results, it was found that ablation of both metal targets in ethanol medium leads to formation of smaller size nanoparticles with narrower size distributions. The influence of laser fluence was also investigated. According to the results, higher laser fluence produces larger mean size nanoparticles with broader size distribution.

Study of vibrations and stabilization of linear collider final doublets at the sub-nanometer scale

International Nuclear Information System (INIS)

Bolzon, B.

2007-11-01

CLIC is one of the current projects of high energy linear colliders. Vertical beam sizes of 0.7 nm at the time of the collision and fast ground motion of a few nanometers impose an active stabilization of the final doublets at a fifth of nanometer above 4 Hz. The majority of my work concerned vibrations and active stabilization study of cantilever and slim beams in order to be representative of the final doublets of CLIC. In a first part, measured performances of different types of vibration sensors associated to an appropriate instrumentation showed that accurate measurements of ground motion are possible from 0.1 Hz up to 2000 Hz on a quiet site. Also, electrochemical sensors answering a priori the specifications of CLIC can be incorporated in the active stabilization at a fifth of nanometer. In a second part, an experimental and numerical study of beam vibrations enabled to validate the efficiency of the numerical prediction incorporated then in the simulation of the active stabilization. Also, a study of the impact of ground motion and of acoustic noise on beam vibrations showed that an active stabilization is necessary at least up to 1000 Hz. In a third part, results on the active stabilization of a beam at its two first resonances are shown down to amplitudes of a tenth of nanometer above 4 Hz by using in parallel a commercial system performing passive and active stabilization of the clamping. The last part is related to a study of a support for the final doublets of a linear collider prototype in phase of finalization, the ATF2 prototype. This work showed that relative motion between this support and the ground is below imposed tolerances (6 nm above 0.1 Hz) with appropriate boundary conditions. (author)

Formation of controllable polymer micropatterns through liquid film electro-dewetting

Science.gov (United States)

Zhou, Shangru; Zheng, Huai; Li, Guoliang; Liu, Jie; Liu, Sheng

2018-04-01

Controllable polymer micropatterns, served as indispensable function structures, are extensively required in many micro/nano scientific areas and engineering applications. Exploring advanced methods of fabricating micropatterns is always a research hotspot. In this article, we introduce a novel method of patterning polymer by the electro-dewetting induced by corona discharge. For the first time, it is observed experimentally that liquid polymer on conductive/non-conductive patterned substrates, spontaneously converges from non-conductive areas to conductive areas under the action of ion wind. Taking advantage of such a flow phenomenon, controllable polymer micropatterns including microbump arrays and microwell arrays are fabricated successfully. Their sizes range from hundreds of microns to millimeters. Micropattern surfaces present an ultra-smooth characteristic, with roughness in the nanometer range.

Treatment to Destroy Chlorohydrocarbon Liquids in the Ground

Science.gov (United States)

Quinn, Jacqueline; Clausen, Christian A., III; Geiger, Cherie L.; Reinhart, Debra; Brooks, Kathleen

2003-01-01

A relatively simple chemical treatment that involves the use of emulsified iron has been found to be effective in remediating groundwater contaminated with trichloroethylene and other dense chlorohydrocarbon liquids. These liquids are members of the class of dense, nonaqueous phase liquids (DNAPLs), which are commonly recognized to be particularly troublesome as environmental contaminants. The treatment converts these liquids into less-harmful products. As a means of remediation of contaminated groundwater, this treatment takes less time and costs less than do traditional pump-and-treat processes. At some sites, long-term leakage and/or dissolution of chlorohydrocarbon liquids from pools and/or sorbed concentrations in rock and soil gives rise to a need to continue pumpand- treat processes for times as long as decades in order to maintain protection of human health and the environment. In contrast, the effects of the emulsified-iron treatment are more lasting, decreasing the need for long-term treatment and monitoring of contaminated areas. The material used in this treatment consists of iron particles with sizes of the order of nanometers to micrometers contained within the micelles of a surfactant-stabilized, biodegradable, oil-in-water emulsion. The emulsion is simple to prepare and consists of relatively inexpensive and environmentally acceptable ingredients: One typical formulation consists of 1.3 weight percent of a food-grade surfactant, 17.5 weight percent of iron particles, 23.2 weight percent of vegetable oil, and 58.0 weight percent of water.

Formative evaluation of a mobile liquid portion size estimation interface for people with varying literacy skills.

Science.gov (United States)

Chaudry, Beenish Moalla; Connelly, Kay; Siek, Katie A; Welch, Janet L

2013-12-01

Chronically ill people, especially those with low literacy skills, often have difficulty estimating portion sizes of liquids to help them stay within their recommended fluid limits. There is a plethora of mobile applications that can help people monitor their nutritional intake but unfortunately these applications require the user to have high literacy and numeracy skills for portion size recording. In this paper, we present two studies in which the low- and the high-fidelity versions of a portion size estimation interface, designed using the cognitive strategies adults employ for portion size estimation during diet recall studies, was evaluated by a chronically ill population with varying literacy skills. The low fidelity interface was evaluated by ten patients who were all able to accurately estimate portion sizes of various liquids with the interface. Eighteen participants did an in situ evaluation of the high-fidelity version incorporated in a diet and fluid monitoring mobile application for 6 weeks. Although the accuracy of the estimation cannot be confirmed in the second study but the participants who actively interacted with the interface showed better health outcomes by the end of the study. Based on these findings, we provide recommendations for designing the next iteration of an accurate and low literacy-accessible liquid portion size estimation mobile interface.

IMPACT OF LIQUIDITY AND SIZE PREMIUM ON EQUITY PRICE FORMATION IN SERBIA

OpenAIRE

Jelena Minović; Boško Živković

2012-01-01

The goal of this paper is to examine the impact of an overall market factor, the factor related to the firm size, the factor related to the ratio of book to market value of companies, and the factor of liquidity risk on expected asset returns in the Serbian market. For this market we estimated different factor models: Capital Asset Pricing Model (CAPM by Sharpe, 1964), Fama-French (FF) model (1992, 1993), Liquidity-augmented CAPM (LCAPM) by Liu (2006), and combination LCAPM with FF factors. W...

Nanometer-scale features in dolomite from Pennsylvanian rocks, Paradox Basin, Utah

Science.gov (United States)

Gournay, Jonas P.; Kirkland, Brenda L.; Folk, Robert L.; Lynch, F. Leo

1999-07-01

Scanning electron microscopy reveals an association between early dolomite in the Pennsylvanian Desert Creek (Paradox Fm.) and small (approximately 0.1 μm) nanometer-scale textures, termed `nannobacteria'. Three diagenetically distinct dolomites are present: early dolomite, limpid dolomite, and baroque dolomite. In this study, only the early dolomite contained nanometer-scale features. These textures occur as discrete balls and rods, clumps of balls, and chains of balls. Precipitation experiments demonstrate that these textures may be the result of precipitation in an organic-rich micro-environment. The presence of these nanometer-scale textures in Pennsylvanian rocks suggests that these early dolomites precipitated in organic-rich, bacterial environments.

RF Circuit Design in Nanometer CMOS

NARCIS (Netherlands)

Nauta, Bram

2007-01-01

With CMOS technology entering the nanometer regime, the design of analog and RF circuits is complicated by low supply voltages, very non-linear (and nonquadratic) devices and large 1/f noise. At the same time, circuits are required to operate over increasingly wide bandwidths to implement modern

Nanometer CMOS ICs from basics to ASICs

CERN Document Server

J M Veendrick, Harry

2017-01-01

This textbook provides a comprehensive, fully-updated introduction to the essentials of nanometer CMOS integrated circuits. It includes aspects of scaling to even beyond 12nm CMOS technologies and designs. It clearly describes the fundamental CMOS operating principles and presents substantial insight into the various aspects of design implementation and application. Coverage includes all associated disciplines of nanometer CMOS ICs, including physics, lithography, technology, design, memories, VLSI, power consumption, variability, reliability and signal integrity, testing, yield, failure analysis, packaging, scaling trends and road blocks. The text is based upon in-house Philips, NXP Semiconductors, Applied Materials, ASML, IMEC, ST-Ericsson, TSMC, etc., courseware, which, to date, has been completed by more than 4500 engineers working in a large variety of related disciplines: architecture, design, test, fabrication process, packaging, failure analysis and software.

Direct observation and analysis of yolk-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

Energy Technology Data Exchange (ETDEWEB)

Asahina, Shunsuke; Suga, Mitsuo; Takahashi, Hideyuki [JEOL Ltd., SM Business Unit, Tokyo (Japan); Young Jeong, Hu [Graduate School of EEWS, WCU/BK21+, KAIST, Daejeon 305-701 (Korea, Republic of); Galeano, Carolina; Schüth, Ferdi [Department of Heterogeneous Catalysis, Max-Planck-Institut für Kohlenforschung, Mülheim (Germany); Terasaki, Osamu, E-mail: terasaki@mmk.su.se, E-mail: terasaki@kaist.ac.kr [Graduate School of EEWS, WCU/BK21+, KAIST, Daejeon 305-701 (Korea, Republic of); Department of Materials and Environmental Chemistry, Berzelii Centre EXSELENT on Porous Materials, Stockholm University, SE-10691 Stockholm (Sweden)

2014-11-01

Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in yolk-shell materials of Au@C, Ru/Pt@C, Au@TiO{sub 2}, and Pt@Polymer. Progresses in the following categories were shown for the yolk-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

Mesoporous TiO2 Micro-Nanometer Composite Structure: Synthesis, Optoelectric Properties, and Photocatalytic Selectivity

Directory of Open Access Journals (Sweden)

Kun Liu

2012-01-01

Full Text Available Mesoporous anatase TiO2 micro-nanometer composite structure was synthesized by solvothermal method at 180°C, followed by calcination at 400°C for 2 h. The as-prepared TiO2 was characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, transmission electron microscope (TEM, and Fourier transform infrared spectrum (FT-IR. The specific surface area and pore size distribution were obtained from N2 adsorption-desorption isotherm, and the optoelectric property of the mesoporous TiO2 was studied by UV-Vis absorption spectrum and surface photovoltage spectra (SPS. The photocatalytic activity was evaluated by photodegradation of sole rhodamine B (RhB and sole phenol aqueous solutions under simulated sunlight irradiation and compared with that of Degussa P-25 (P25 under the same conditions. The photodegradation preference of this mesoporous TiO2 was also investigated for an RhB-phenol mixed solution. The results show that the TiO2 composite structure consists of microspheres (∼0.5–2 μm in diameter and irregular aggregates (several hundred nanometers with rough surfaces and the average primary particle size is 10.2 nm. The photodegradation activities of this mesoporous TiO2 on both RhB and phenol solutions are higher than those of P25. Moreover, this as-prepared TiO2 exhibits photodegradation preference on RhB in the RhB-phenol mixture solution.

Extreme Wetting-Resistant Multiscale Nano-/Microstructured Surfaces for Viscoelastic Liquid Repellence

Directory of Open Access Journals (Sweden)

Aoythip Chunglok

2016-01-01

Full Text Available We demonstrate exceptional wetting-resistant surfaces capable of repelling low surface tension, non-Newtonian, and highly viscoelastic liquids. Theoretical analysis and experimental result confirm that a higher level of multiscale roughness topography composed of at least three structural length scales, ranging from nanometer to supermicron sizes, is crucial for the reduction of liquid-solid adhesion hysteresis. With Cassie-Baxter nonwetting state satisfied at all roughness length scales, the surface has been proven to effectively repel even highly adhesive liquid. Practically, this high-level hierarchical structure can be achieved through fractal-like structures of silica aggregates induced by siloxane oligomer interparticle bridges. The induced aggregation and surface functionalization of the silica particles can be performed simultaneously within a single reaction step, by utilizing trifunctional fluoroalkylsilane precursors that largely form a disordered fluoroalkylsiloxane grafting layer under the presence of sufficient native moisture preadsorbed at the silica surface. Spray-coating deposition of a particle surface layer on a precoated primer layer ensures facile processability and scalability of the fabrication method. The resulting low-surface-energy multiscale roughness exhibits outstanding liquid repellent properties, generating equivalent lotus effect for highly viscous and adhesive natural latex concentrate, with apparent contact angles greater than 160°, and very small roll-off angles of less than 3°.

Size effect in X-ray and electron diffraction patterns from hydroxyapatite particles

International Nuclear Information System (INIS)

Suvorova, E.I.; Buffat, P.-A.

2001-01-01

High-resolution transmission electron microscopy (HRTEM), electron microdiffraction, and X-ray diffraction were used to study hydroxyapatite specimens with particle sizes from a few nanometers to several hundreds of nanometers. Diffuse scattering (without clear reflections in transmission diffraction patterns) or strongly broadened peaks in X-ray diffraction patterns are characteristic for agglomerated hydroxyapatite nanocrystals. However, HRTEM and microdiffraction showed that this cannot be considered as an indication of the amorphous state of the matter but rather as the demonstration of size effect and the morphological and structural features of hydroxyapatite nanocrystals

Predicting Nanoscale Dynamics of a Glass-Forming Liquid from Its Macroscopic Bulk Behavior and Vice Versa.

Science.gov (United States)

Adrjanowicz, Karolina; Kaminski, Kamil; Tarnacka, Magdalena; Szklarz, Grzegorz; Paluch, Marian

2017-02-02

The properties of a molecular liquid confined at the nanometer length scale can be very distinct from the bulk. For that reason, the macro- and the nanoscopic behaviors of glass-forming liquids are regarded as two nonconnected realms, governed by their own rules. Here, we show that the glassy dynamics in molecular liquids confined to nanometer pores might obey the density scaling relation, ρ γ /T, just like in bulk fluids. Even more surprisingly, the same value of the scaling exponent γ superposes the α-relaxation time measured at different state points in nanoscale confinement and upon increased pressure. We report this remarkable finding for van der Waals liquids tetramethyl-tetraphenyl-trisiloxane (DC704) and polyphenyl ether (5PPE), considered as simple, single-parameter liquids. Demonstrating that the density scaling idea can be fulfilled in both environments opens an exciting possibility to predict the dynamic features of the nanoconfined system close to its glass-transition temperature from the high-pressure studies of the bulk liquid. Likewise, we can describe the viscous liquid dynamics at any given combination of temperature and pressure based on analysis of its behavior in nanopores.

Displacement laser interferometry with sub-nanometer uncertainty

NARCIS (Netherlands)

Cosijns, S.J.A.G.

2004-01-01

Development in industry is asking for improved resolution and higher accuracy in mechanical measurement. Together with miniaturization the demand for sub nanometer uncertainty on dimensional metrology is increasing rapidly. Displacement laser interferometers are used widely as precision displacement

Sodium Caseinate-Carrageenan Biopolymeric Nanocomplexes as a Carrier of Vitamin D: Study of Complex Formation, Particles Size and Encapsulation Efficiency

Directory of Open Access Journals (Sweden)

Maryam Khoshmanzar

2014-04-01

Full Text Available The protein-polysaccharide complex-based nanocapsule is one type of polymeric nanocarrier which can be potentially useful for encapsulation of hydrophobic nutraceuticals. In this research, caseinate-carrageenan complex was used for encapsulation of vitamin D. The complex formation between caseinate and carrageenan was carried out by lowering the pH under isoelectric point of protein. The Fourier transform infrared spectroscopy (FTIR and differential scanning colorimetry (DSC confirmed complex formation between carrageenan, caseinate and vitamin D. The particle size of 1% caseinate particles was in the range of 150-300 nanometer and by addition of vitamin D the particle size increased to 450-750 nanometer. Moreover, carrageenan of all concentrations (at constant concentration of caseinate (1% and pH4.9 resulted in lower particle size below 100 nanometer. The stability of caseinate and its complex formation with carrageenan showed that encapsulation was achieved at 45% efficiency and also vitamin D stability (during 5 days storage was higher in nanocomplex compared to pure caseinate particles (60-63% compared to 53%. The complex formation between caseinate and carrageenan was carried out by pH decreasing under isoelectric point of protein. The FTIR and DSC confirmed complex formation between carrageenan, caseinate and vitamin D. The particle size of caseinate 1% particles were in the range of 150 -300 nanometer and with adding vitamin D, particle size increased to 450-750 nanometer. Moreover, adding carrageenan at all used concentration (at constant concentration of caseinate (1% and pH4.9 resulted in reduced particle size to less than 100 nanometer and vitamin D stability (during 5 days storage was higher (60-63% in nanocomplex compared to pure caseinate particles (53%.The protein-polysaccharide complex based nanocapsule is one type of the polymeric nanocarriers which can potentially be used for encapsulation of hydrophobic nutraceuticals. In

The structure of the solid-liquid interface: atomic size effect; La structure de l'interface solide-liquide: effet de taille atomique

Energy Technology Data Exchange (ETDEWEB)

Geysermans, P.; Pontikis, V. [Centre National de la Recherche Scientifique (CNRS), 94 - Vitry-sur-Seine (France). Centre d' Etudes de Chimie Metallurgique

2002-09-01

The atomic structure of the solid-liquid heterophase interface was investigated by using molecular dynamics. Two kinds of systems were studied; the first one was crystalline copper with (100) and (111) surface terminations in contact with liquid aluminium, while in the second one the interface was modelled by two systems in contact made of Lennard-Jones particles with different size ({sigma}) and energy ({epsilon}) parameters. We found that at the interface the liquid was layered whatever the crystallographic orientation of the surface. The layering of the liquid is still preserved when the ratio of particles sites ({chi}={sigma}{sub 1}/{sigma}{sub 2}) changes while an epitaxial relationship is always found between the crystal and the first liquid layer. The average density of the latter is closely related to the {chi} value. (authors)

Facile method for liquid-exfoliated graphene size prediction by UV-visible spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Ismail, Zulhelmi, E-mail: helmie83@hotmail.com [Faculty of Manufacturing Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang (Malaysia); Yusoh, Kamal, E-mail: kamal@ump.edu.my [Faculty of Chemical Engineering and Natural Resources, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Kuantan, Pahang (Malaysia)

2016-07-19

In this work, an application of UV spectroscopy for facile prediction of liquid –exfoliated graphene size is discussed. Dynamic light scattering method was used to estimate the graphene flake size ( whilst UV spectroscopy measurement was carried out for extinction coefficient value (ε) determination. It was found that the value of (ε) decreased gradually as the graphene size was further reduced after intense sonication time (7h). This observation showed the influence of sonication time on electronic structure of graphene. A mathematical equation was derived from log-log graph for correlation between () and (ε) value. Both values can be expressed in a single equation as ( = (3.4 × 10{sup −2}) ε{sup 1.2}).

Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

Directory of Open Access Journals (Sweden)

Shunsuke Asahina

2014-11-01

Full Text Available Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in york-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the york-shell materials: (i resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii sample preparation for observing internal structures; and (iii X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

Nanometer Linear Focusing of Hard X Rays by a Multilayer Laue Lens

International Nuclear Information System (INIS)

Kang, H.C.; Stephenson, G.B.; Maser, J.; Liu, C.; Conley, R.; Macrander, A.T.; Vogt, S.

2006-01-01

We report on a type of linear zone plate for nanometer-scale focusing of hard x rays, a multilayer Laue lens (MLL), produced by sectioning a multilayer and illuminating it in Laue diffraction geometry. Because of its large optical depth, a MLL spans the diffraction regimes applicable to a thin Fresnel zone plate and a crystal. Coupled wave theory calculations indicate that focusing to 5 nm or smaller with high efficiency should be possible. Partial MLL structures with outermost zone widths as small as 10 nm have been fabricated and tested with 19.5 keV synchrotron radiation. Focal sizes as small as 30 nm with efficiencies up to 44% are measured

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Science.gov (United States)

Yu, Yi-Hsien; Wang, Xuezhen; Shinde, Abhijeet; Cheng, Zhengdong

2016-01-01

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2·H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior. PMID:27284765

On the validity of the Navier-Stokes equations for nanoscale liquid flows: The role of channel size

Directory of Open Access Journals (Sweden)

Chong Liu

2011-09-01

Full Text Available In this work, we investigate the validity of the Navier-Stokes (NS equations for nanoscale liquid flows through molecular dynamics simulations. We focus on the role of channel size by considering the fluid-wall interaction. Liquid flows between two planar parallel walls driven by an external force with channel size ranging from 2 to 80 nm are studied. The volumetric flux is computed and the dependence of the volumetric flux on the channel size is explained both qualitatively and quantitatively. It is found that the flow is sensitive to the fluid-wall binding energy and the classical fluid mechanics falls apart in small nanochannels. However, the wall effects become insignificant and the NS equations are valid when the channel size is larger than about 150 molecular diameters (∼ 50 nm.

Experimental investigation of liquid-liquid system drop size distribution in Taylor-Couette flow and its application in the CFD simulation

Science.gov (United States)

Farzad, Reza; Puttinger, Stefan; Pirker, Stefan; Schneiderbauer, Simon

Liquid-liquid systems are widely used in the several industries such as food, pharmaceutical, cosmetic, chemical and petroleum. Drop size distribution (DSD) plays a key role as it strongly affects the overall mass and heat transfer in the liquid-liquid systems. To understand the underlying mechanisms single drop breakup experiments have been done by several researchers in the Taylor-Couette flow; however, most of those studies concentrate on the laminar flow regime and therefore, there is no sufficient amount of data in the case of in turbulent flows. The well-defined pattern of the Taylor-Couette flow enables the possibility to investigate DSD as a function of the local fluid dynamic properties, such as shear rate, which is in contrast to more complex devices such as stirred tank reactors. This paper deals with the experimental investigation of liquid-liquid DSD in Taylor-Couette flow. From high speed camera images we found a simple correlation for the Sauter mean diameter as a function of the local shear employing image processing. It is shown that this correlation holds for different oil-in-water emulsions. Finally, this empirical correlation for the DSD is used as an input data for a CFD simulation to compute the local breakup of individual droplets in a stirred tank reactor.

Development of a sub-nanometer positioning device: combining a new linear motor with linear motion ball guide ways

International Nuclear Information System (INIS)

Otsuka, J; Tanaka, T; Masuda, I

2010-01-01

A new type of linear motor described in this note has some advantages compared with conventional motors. The attractive magnetic force between the stator (permanent magnets) and mover (armature) is diminished almost to zero. The efficiency is better because the magnetic flux leakage is very small, the size of motor is smaller and detent (force ripple) is smaller than for conventional motors. Therefore, we think that this motor is greatly suitable for ultra-precision positioning as an actuator. An ultra-precision positioning device using this motor and linear motion ball guide ways is newly developed by making the device very rigid and using a suitable control method. Moreover, the positioning performance is evaluated by a positioning resolution, and deviation and dispersion errors. As a result of repeated step response tests, the positioning resolution is 0.3 nm, with the deviation error and dispersion error (3σ) being sub-nanometer. Consequently, the positioning device achieves sub-nanometer positioning. (technical design note)

Size and temperature consideration in the liquid layer growth from nanovoids and the melting model construction

International Nuclear Information System (INIS)

Li, H.; Liang, X.H.; Li, M.

2014-01-01

A new model for the solid melting point T m (D) from nanovoids is proposed through considering the liquid layer growth behavior. This model, which does not have any adjustable parameter, introduces the classical thermodynamic treatment, i.e., the liquid nucleation and growth theory, for nanoparticle melting. With increased void diameter D, T m (D) approaches to T m0 . Moreover, T m (D) > T m0 for a small void (T m0 is the bulk melting point). In other words, the solid can be significantly superheated especially when D decreases, even if the difference of interface energy is larger than zero. This finding can be expected from the negatively curved surface of the void. The model predictions are consistent with the molecular dynamic (MD) simulation results for argon solids. Moreover, the growth of liquid layer from void surface relies on both size and temperature, which directly determine liquid layer thickness, and only when liquid layer thickness reaches to a critical value, can void become instable. - Highlights: • A united model for the crystal melting point from nanovoids is established. • Melting point increases with decreased void size. • The result is expected from the negatively curved surface of the void. • The prediction is agreed well with the MD simulation results

Grain-size effect on the electrical properties of nanocrystalline indium tin oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Hoon [Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); Kim, Young Heon, E-mail: young.h.kim@kriss.re.kr [Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); University of Science & Technology, 217 Gajeong-Ro, Yuseong-Gu, Daejeon 305-350 (Korea, Republic of); Ahn, Sang Jung [Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); University of Science & Technology, 217 Gajeong-Ro, Yuseong-Gu, Daejeon 305-350 (Korea, Republic of); Ha, Tae Hwan [University of Science & Technology, 217 Gajeong-Ro, Yuseong-Gu, Daejeon 305-350 (Korea, Republic of); Future Biotechnology Research Division, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-Gu, Daejeon 305-806 (Korea, Republic of); Kim, Hong Seung [Department of Nano Semiconductor Engineering, Korea Maritime and Ocean University, 727 Taejong-Ro, Busan 606-791 (Korea, Republic of)

2015-09-15

Highlights: • Nanometer-sized small grains were observed in the ITO thin films. • The grain size increased as the post-thermal annealing temperature increased. • The mobility of ITO thin films increased with increasing grain size. • The ITO film annealed at 300 °C was an amorphous phase, while the others were polycrystalline structure. - Abstract: In this paper, we demonstrate the electrical properties, depending on grain size, of nanocrystalline indium tin oxide (ITO) thin films prepared with a solution process. The size distributions of nanometer-sized ITO film grains increased as the post-annealing temperature increased after deposition; the grain sizes were comparable with the calculated electron mean free path. The mobility of ITO thin films increased with increasing grain size; this phenomenon was explained by adopting the charge-trapping model for grain boundary scattering. These findings suggest that it is possible to improve mobility by reducing the number of trapping sites at the grain boundary.

Vapor-Liquid-Solid Etch of Semiconductor Surface Channels by Running Gold Nanodroplets.

Science.gov (United States)

Nikoobakht, Babak; Herzing, Andrew; Muramoto, Shin; Tersoff, Jerry

2015-12-09

We show that Au nanoparticles spontaneously move across the (001) surface of InP, InAs, and GaP when heated in the presence of water vapor. As they move, the particles etch crystallographically aligned grooves into the surface. We show that this process is a negative analogue of the vapor-liquid-solid (VLS) growth of semiconductor nanowires: the semiconductor dissolves into the catalyst and reacts with water vapor at the catalyst surface to create volatile oxides, depleting the dissolved cations and anions and thus sustaining the dissolution process. This VLS etching process provides a new tool for directed assembly of structures with sublithographic dimensions, as small as a few nanometers in diameter. Au particles above 100 nm in size do not exhibit this process but remain stationary, with oxide accumulating around the particles.

Bismuth-ceramic nanocomposites through ball milling and liquid crystal synthetic methods

Science.gov (United States)

Dellinger, Timothy Michael

Three methods were developed for the synthesis of bismuth-ceramic nanocomposites, which are of interest due to possible use as thermoelectric materials. In the first synthetic method, high energy ball milling of bismuth metal with either MgO or SiO2 was found to produce nanostructured bismuth dispersed on a ceramic material. The morphology of the resulting bismuth depended on its wetting behavior with respect to the ceramic: the metal wet the MgO, but did not wet on the SiO2. Differential Scanning Calorimetry measurements on these composites revealed unusual thermal stability, with nanostructure retained after multiple cycles of heating and cooling through the metal's melting point. The second synthesis methodology was based on the use of lyotropic liquid crystals. These mixtures of water and amphiphilic molecules self-assemble to form periodic structures with nanometer-scale hydrophilic and hydrophobic domains. A novel shear mixing methodology was developed for bringing together reactants which were added to the liquid crystals as dissolved salts. The liquid crystals served to mediate synthesis by acting as nanoreactors to confine chemical reactions within the nanoscale domains of the mesophase, and resulted in the production of nanoparticles. By synthesizing lead sulfide (PbS) and bismuth (Bi) particles as proof-of-concept, it was shown that nanoparticle size could be controlled by controlling the dimensionality of the nanoreactors through control of the liquid crystalline phase. Particle size was shown to decrease upon going from three-dimensionally percolating nanoreactors, to two dimensional sheet-like nanoreactors, to one dimensional rod-like nanoreactors. Additionally, particle size could be controlled by varying the precursor salt concentration. Since the nanoparticles did not agglomerate in the liquid crystal immediately after synthesis, bismuth-ceramic nanocomposites could be prepared by synthesizing Bi nanoparticles and mixing in SiO2 particles which

Spinel Li2CoTi3O8 nanometer obtained for application as pigment

International Nuclear Information System (INIS)

Costa de Camara, M. S.; Alves Pimentel, L.; Longo, E.; Nobrega Azevedo, L. da; Araujo Melo, D. M. de

2016-01-01

Pigments are used in ceramics, cosmetics, inks, and other applications widely materials. To this must be single and easily reproducible. Moreover, the pigments obtained in the nanoscale are more stable, reproducible and highlight color in small amounts compared with those obtained in micrometer scale. The mixed oxides with spinel structures AB 2 O 4 have important applications, including: pigments, refractories, catalytic and electronic ceramics. In this context, the aim of this work was the preparation of powder Li 2 CoTi 3 O 8 spinel phase with nanometer particle size of the polymeric precursor method (Pechini) and characterization by means of thermal analysis (TG/DTA) X-ray diffraction (XRD), refined by the Rietveld method, BET, transmission electron microscopy (TEM), Raman and colorimetric coordinates. The pigment was obtained by heat treatment of 400 degree centigrade to 1000 degree centigrade after pyrolysis at 300 degree centigrade/1 h for removing the organic material. Li 2 CoTi 3 O 8 desired spinel phase was obtained from 500 degree centigrade, and presenting stability nanometer to about 1.300 degree centigrade. Spinel green phase introduced at temperatures in the range of 400 degree centigrade and 500 degree centigrade, and 600 degree centigrade at temperatures between blue and 1000 degree centigrade. (Author)

Analysis of nano-meter structure in Ti implanted polymers

International Nuclear Information System (INIS)

Zhou Gu; Wu Yuguang; Zhang Tonghe; Zhao Xinrong

2001-01-01

Polyethylene terephthalate (PET) is modified with Ti ion implantation to a dose of 1x10 17 to 2 x 10 17 cm -2 by using a metal vapor vacuum arc(MEVVA)source. Nano-meter structures in the implanted sample are observed by means of transmission electron microscope (TEM). The influence of ion dose on the structure is indicated. The results show that dense nano-meter phases are dispersed uniformly in the implanted layer. TEM cross section indicates that there is a three-layer structure in the implanted PET. It is found that a metallurgical surface is formed. Therefore the hardness, wear resistance and conductive properties of PET are improved after metal ion implantation. The mechanism of electrical conduction will be discussed

Nanometer-Scale Dissection of Chromosomes by Atomic Force Microscopy Combined with Heat-Denaturing Treatment

Science.gov (United States)

Tsukamoto, Kazumi; Kuwazaki, Seigo; Yamamoto, Kimiko; Shichiri, Motoharu; Yoshino, Tomoyuki; Ohtani, Toshio; Sugiyama, Shigeru

2006-03-01

We have developed a method for dissecting chromosome fragments with a size of a few hundred nanometers by atomic force microscopy (AFM). By using this method, we demonstrated reproducible dissections of silkworm chromosomes in the pachytene phase. The dissected fragments were successfully recovered on the cantilever tips, as confirmed by fluorescent microscopy using fluorescent stained chromosomes. To recover dissected chromosome fragments from a larger chromosome, such as the human metaphase chromosome of a somatic cell, heat denaturation was found to be effective. Further improvements in this method may lead to a novel tool for isolating valuable genes and/or investigating local genome structures in the near future.

Gaining Control over Radiolytic Synthesis of Uniform Sub-3-nanometer Palladium Nanoparticles: Use of Aromatic Liquids in the Electron Microscope.

Science.gov (United States)

Abellan, Patricia; Parent, Lucas R; Al Hasan, Naila; Park, Chiwoo; Arslan, Ilke; Karim, Ayman M; Evans, James E; Browning, Nigel D

2016-02-16

Synthesizing nanomaterials of uniform shape and size is of critical importance to access and manipulate the novel structure-property relationships arising at the nanoscale, such as catalytic activity. In this work, we synthesize Pd nanoparticles with well-controlled size in the sub-3 nm range using scanning transmission electron microscopy (STEM) in combination with an in situ liquid stage. We use an aromatic hydrocarbon (toluene) as a solvent that is very resistant to high-energy electron irradiation, which creates a net reducing environment without the need for additives to scavenge oxidizing radicals. The primary reducing species is molecular hydrogen, which is a widely used reductant in the synthesis of supported metal catalysts. We propose a mechanism of particle formation based on the effect of tri-n-octylphosphine (TOP) on size stabilization, relatively low production of radicals, and autocatalytic reduction of Pd(II) compounds. We combine in situ STEM results with insights from in situ small-angle X-ray scattering (SAXS) from alcohol-based synthesis, having similar reduction potential, in a customized microfluidic device as well as ex situ bulk experiments. This has allowed us to develop a fundamental growth model for the synthesis of size-stabilized Pd nanoparticles and demonstrate the utility of correlating different in situ and ex situ characterization techniques to understand, and ultimately control, metal nanostructure synthesis.

Deposition of Size-Selected Cu Nanoparticles by Inert Gas Condensation

Directory of Open Access Journals (Sweden)

Martínez E

2009-01-01

Full Text Available Abstract Nanometer size-selected Cu clusters in the size range of 1–5 nm have been produced by a plasma-gas-condensation-type cluster deposition apparatus, which combines a grow-discharge sputtering with an inert gas condensation technique. With this method, by controlling the experimental conditions, it was possible to produce nanoparticles with a strict control in size. The structure and size of Cu nanoparticles were determined by mass spectroscopy and confirmed by atomic force microscopy (AFM and scanning electron transmission microscopy (STEM measurements. In order to preserve the structural and morphological properties, the energy of cluster impact was controlled; the energy of acceleration of the nanoparticles was in near values at 0.1 ev/atom for being in soft landing regime. From SEM measurements developed in STEM-HAADF mode, we found that nanoparticles are near sized to those values fixed experimentally also confirmed by AFM observations. The results are relevant, since it demonstrates that proper optimization of operation conditions can lead to desired cluster sizes as well as desired cluster size distributions. It was also demonstrated the efficiency of the method to obtain size-selected Cu clusters films, as a random stacking of nanometer-size crystallites assembly. The deposition of size-selected metal clusters represents a novel method of preparing Cu nanostructures, with high potential in optical and catalytic applications.

Bridging the Gap between the Nanometer-Scale Bottom-Up and Micrometer-Scale Top-Down Approaches for Site-Defined InP/InAs Nanowires.

Science.gov (United States)

Zhang, Guoqiang; Rainville, Christophe; Salmon, Adrian; Takiguchi, Masato; Tateno, Kouta; Gotoh, Hideki

2015-11-24

This work presents a method that bridges the gap between the nanometer-scale bottom-up and micrometer-scale top-down approaches for site-defined nanostructures, which has long been a significant challenge for applications that require low-cost and high-throughput manufacturing processes. We realized the bridging by controlling the seed indium nanoparticle position through a self-assembly process. Site-defined InP nanowires were then grown from the indium-nanoparticle array in the vapor-liquid-solid mode through a "seed and grow" process. The nanometer-scale indium particles do not always occupy the same locations within the micrometer-scale open window of an InP exposed substrate due to the scale difference. We developed a technique for aligning the nanometer-scale indium particles on the same side of the micrometer-scale window by structuring the surface of a misoriented InP (111)B substrate. Finally, we demonstrated that the developed method can be used to grow a uniform InP/InAs axial-heterostructure nanowire array. The ability to form a heterostructure nanowire array with this method makes it possible to tune the emission wavelength over a wide range by employing the quantum confinement effect and thus expand the application of this technology to optoelectronic devices. Successfully pairing a controllable bottom-up growth technique with a top-down substrate preparation technique greatly improves the potential for the mass-production and widespread adoption of this technology.

Study of 'liquid gold' coatings: Thermal decomposition and formation of metallic thin films

International Nuclear Information System (INIS)

Deram, V.; Turrell, S.; Darque-Ceretti, E.; Aucouturier, M.

2006-01-01

Organo-metallic solutions called liquid gold are largely used to obtain thin gilded films which are employed for decorative, technological and functional uses. However, these films often prove to be fragile with respect to use, resulting in loss of brilliance or even eventual film removal. An understanding of the behaviour of the layers requires good knowledge of the materials themselves. The present work was undertaken to better understand the evolution of the structural properties of liquid gold as it undergoes heat-processing. Accordingly, we followed the thermal decomposition processes of liquid gold coatings and the formation of the gilded metal layer using a combination of experimental techniques. First, thermal analyses coupled with mass spectrometry and infrared spectroscopy gave information concerning the decomposition of the organic medium. It has been found that the process of film formation can be decomposed into three steps, the second of which is an abrupt transition between 300 and 350 deg. C. Details on this transition have been obtained using real-time X-ray Diffraction and Rutherford Backscattering Spectrometry. Above 350 deg. C, the microstructure of the coating is reorganized to obtain a final layer which contains particles, of the size of a few hundreds nanometers, as shown by Transmission Electron Microscopy

Size determinations of plutonium colloids using autocorrelation photon spectroscopy

International Nuclear Information System (INIS)

Triay, I.R.; Rundberg, R.S.; Mitchell, A.J.; Ott, M.A.; Hobart, D.E.; Palmer, P.D.; Newton, T.W.; Thompson, J.L.

1989-01-01

Autocorrelation Photon Spectroscopy (APS) is a light-scattering technique utilized to determine the size distribution of colloidal suspensions. The capabilities of the APS methodology have been assessed by analyzing colloids of known sizes. Plutonium(IV) colloid samples were prepared by a variety of methods including: dilution; peptization; and alpha-induced auto-oxidation of Pu(III). The size of theses Pu colloids was analyzed using APS. The sizes determined for the Pu colloids studied varied from 1 to 370 nanometers. 7 refs., 5 figs., 3 tabs

Flip-flop design in nanometer CMOS from high speed to low energy

CERN Document Server

Alioto, Massimo; Palumbo, Gaetano

2015-01-01

This book provides a unified treatment of Flip-Flop design and selection in nanometer CMOS VLSI systems. The design aspects related to the energy-delay tradeoff in Flip-Flops are discussed, including their energy-optimal selection according to the targeted application, and the detailed circuit design in nanometer CMOS VLSI systems. Design strategies are derived in a coherent framework that includes explicitly nanometer effects, including leakage, layout parasitics and process/voltage/temperature variations, as main advances over the existing body of work in the field. The related design tradeoffs are explored in a wide range of applications and the related energy-performance targets. A wide range of existing and recently proposed Flip-Flop topologies are discussed. Theoretical foundations are provided to set the stage for the derivation of design guidelines, and emphasis is given on practical aspects and consequences of the presented results. Analytical models and derivations are introduced when needed to gai...

A novel ultrasound based technique for classifying gas bubble sizes in liquids

International Nuclear Information System (INIS)

Hussein, Walid; Khan, Muhammad Salman; Zamorano, Juan; Espic, Felipe; Yoma, Nestor Becerra

2014-01-01

Characterizing gas bubbles in liquids is crucial to many biomedical, environmental and industrial applications. In this paper a novel method is proposed for the classification of bubble sizes using ultrasound analysis, which is widely acknowledged for being non-invasive, non-contact and inexpensive. This classification is based on 2D templates, i.e. the average spectrum of events representing the trace of bubbles when they cross an ultrasound field. The 2D patterns are obtained by capturing ultrasound signals reflected by bubbles. Frequency-domain based features are analyzed that provide discrimination between bubble sizes. These features are then fed to an artificial neural network, which is designed and trained to classify bubble sizes. The benefits of the proposed method are that it facilitates the processing of multiple bubbles simultaneously, the issues concerning masking interference among bubbles are potentially reduced and using a single sinusoidal component makes the transmitter–receiver electronics relatively simpler. Results from three bubble sizes indicate that the proposed scheme can achieve an accuracy in their classification that is as high as 99%. (paper)

Determination of redox reaction rates and orders by in situ liquid cell electron microscopy of Pd and Au solution growth.

Science.gov (United States)

Sutter, Eli A; Sutter, Peter W

2014-12-03

In-situ liquid cell transmission and scanning transmission electron microscopy (TEM/STEM) experiments are important, as they provide direct insight into processes in liquids, such as solution growth of nanoparticles, among others. In liquid cell TEM/STEM redox reaction experiments, the hydrated electrons e(-)aq created by the electron beam are responsible for the reduction of metal-ion complexes. Here we investigate the rate equation of redox reactions involving reduction by e(-)aq generated by the electron beam during in situ liquid TEM/STEM. Specifically we consider the growth of Pd on Au seeds in aqueous solutions containing Pd-chloro complexes. From the quantification of the rate of Pd deposition at different electron beam currents and as a function of distance from a stationary, nanometer-sized exciting beam, we determine that the reaction is first order with respect to the concentration of hydrated electrons, [e(-)aq]. By comparing Pd- and Au-deposition, we further demonstrate that measurements of the local deposition rate on nanoparticles in the solution via real-time imaging can be used to measure not only [e(-)aq] but also the rate of reduction of a metal-ion complex to zerovalent metal atoms in solution.

The microstructural evolution of nanometer ruthenium films in Ru/C multilayers with thermal treatments

International Nuclear Information System (INIS)

Nguyen, T.D.; Gronsky, R.; Kortright, J.B.

1991-04-01

The evolution of nanometer Ru films sandwiched between various C layer thickness with thermal treatments was studied by plan-view and cross-sectional Transmission Electron Microscopy. Plan-view observation provides information on the Ru grain size, while cross- sectional studies allow examination of the multilayer morphology. After annealing at 800 degrees C for 30 minutes, the grain size in the 2 and 4 nm Ru layers show little difference from each other, while that in the 1 nm Ru layers depends strongly on the thickness of the C layers in the multilayers. It increases with decreasing C layer thickness. Agglomeration of the Ru layers is observed in 1nm Ru/1nm C multilayers after annealing at 600 degrees C for 30 minutes. The evolution of the microstructures and layered structure stability of the Ru/C system is compared to that of W/C and Ru/B 4 C systems. 10 refs., 2 figs

Effect of particle size on laser-induced breakdown spectroscopy analysis of alumina suspension in liquids

International Nuclear Information System (INIS)

Diaz Rosado, José Carlos; L'hermite, Daniel; Levi, Yves

2012-01-01

The analysis by Laser Induced Breakdown Spectroscopy (LIBS) was proposed for the detection and the quantification of different elements in water even when the analyte is composed of particles in suspension. We have studied the effect of particle size on the LIBS signal during liquid analysis. In our study we used different particle sizes (from 2 μm to 90 μm) of Al 2 O 3 in suspension in water. The results were compared to the signal obtained in the case of dissolved aluminum. In the case of particles, a linear correlation between the LIBS signal versus concentration was found but a significant decrease in the slope of the calibration curve was found when the particle size increased. Several hypotheses have been tested and only a partial ablation of the particles might explain this decrease in signal intensity. This effect probably does not occur at smaller particle size. We estimated 860 nm/pulse as ablated thickness from the top of the particle. A statistical analysis over all data obtained allowed us to calculate 100 μm as ablated water column depth. - Highlights: ► We have identified a decrease of calibration curve when particle size increases. ► Partial particle ablation has been identified as the origin of this effect. ► The ablation rate on Al 2 O 3 particles in suspension in water has been estimated. ► We can determine the deepness of the interaction volume into the liquid.

A model based approach to reference-free straightness measurement at the Nanometer Comparator

Science.gov (United States)

Weichert, C.; Stavridis, M.; Walzel, M.; Elster, C.; Wiegmann, A.; Schulz, M.; Köning, R.; Flügge, J.; Tutsch, R.

2009-06-01

The Nanometer Comparator is the PTB reference length measuring machine for high precision calibrations of line scales and encoder systems. Up to now the Nanometer Comparator allows to measure the position of line structures in one dimension only. For high precision characterisations of masks, scales and incremental encoders, the measurement of the straightness of graduations is a requirement from emerging lithography techniques. Therefore the Nanometer Comparator will be equipped with an additional short range measurement system in the Y-direction, realized as a single path plane mirror interferometer and supposed to achieve sub-nm uncertainties. To compensate the topography of the Y-mirror, the Traceable Multi Sensor (TMS) method will be implemented to achieve a reference-free straightness measurement. Virtual experiments are used to estimate the lower accuracy limit and to determine the sensitive parameters. The virtual experiments contain the influence of the positioning devices, interferometer errors as well as non-perfect adjustment and fabrication of the machine geometry. The whole dynamic measurement process of the Nanometer Comparator including its influence on the TMS analysis, e.g. non-equally spaced measurement points, is simulated. We will present the results of these virtual experiments as well as the most relevant error sources for straightness measurement, incorporating the low uncertainties of the existing and planned measurement systems.

Evidence of a rolling motion of a microparticle on a silicon wafer in a liquid environment

Energy Technology Data Exchange (ETDEWEB)

Schiwek, Simon; Stark, Robert W., E-mail: stark@csi.tu-darmstadt.de, E-mail: dietz@csi.tu-darmstadt.de; Dietz, Christian, E-mail: stark@csi.tu-darmstadt.de, E-mail: dietz@csi.tu-darmstadt.de [Physics of Surfaces, Center of Smart Interfaces and Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Str. 10, 64287 Darmstadt (Germany); Meckel, Tobias [Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt (Germany)

2016-05-21

The interaction of micro- and nanometer-sized particles with surfaces plays a crucial role when small-scale structures are built in a bottom-up approach or structured surfaces are cleaned in the semiconductor industry. For a reliable quantification of the interaction between individual particles and a specific surface, however, the motion type of the particle must be known. We developed an approach to unambiguously distinguish between sliding and rolling particles. To this end, fluorescent particles were partially bleached in a confocal laser scanning microscope to tailor an optical inhomogeneity, which allowed for the identification of the characteristic motion pattern. For the manipulation, the water flow generated by a fast moving cantilever-tip of an atomic force microscope enabled the contactless pushing of the particle. We thus experimentally evidenced a rolling motion of a micrometer-sized particle directly with a fluorescence microscope. A similar approach could help to discriminate between rolling and sliding particles in liquid flows of microfluidic systems.

A general approach to homogeneous sub-nanometer metallic particle/graphene composites by S-coordinator

Science.gov (United States)

Wang, Senhao; Wang, Wei; Gu, Shangzhi; Zhang, Guoxin; Song, Ningning

2018-05-01

In this study, sulphur-modified reduced graphene oxide (S-rGO) was employed as substrate to investigate the growth mechanism of metal and metallic nanoparticles (NPs). It is observed that the monodispersed Au, SnO2, FeO(OH) and Co3S4 NPs in sub-nanometer (sub-nm) with narrow size distribution were successfully anchored on S-rGO, respectively. The results indicate that the S contained radicals, viz. the Cdbnd S and Csbnd Ssbnd C functional groups play an important role in determining the homogeneous distribution of NPs on S-rGO by providing active sites for the NPs anchoring and nucleation. In additional, as anode materials for lithium ion batteries (LIBs), the as-synthesized sub-nm sized Co3S4/S-rGO and SnO2/S-rGO composites show excellent Li storage performance. It could be stabilized at ca. 600 mAh/g after formation cycle with the coulombic efficiency of 98%. It is expected that the strategy of growing sub-nm sized metallic component onto graphene by applying sulphur functionalities could be utilized as a general method to prepare monodispersed graphene-based NPs with other metals, especially with transition metals in sub-nm sizes.

Assessing the concept of structure sensitivity or insensitivity for sub-nanometer catalyst materials

Science.gov (United States)

Crampton, Andrew S.; Rötzer, Marian D.; Ridge, Claron J.; Yoon, Bokwon; Schweinberger, Florian F.; Landman, Uzi; Heiz, Ueli

2016-10-01

The nature of the nano-catalyzed hydrogenation of ethylene, yielding benchmark information pertaining to the concept of structure sensitivity/insensitivity and its applicability at the bottom of the catalyst particle size-range, is explored with experiments on size-selected Ptn (n = 7-40) clusters soft-landed on MgO, in conjunction with first-principles simulations. As in the case of larger particles both the direct ethylene hydrogenation channel and the parallel hydrogenation-dehydrogenation ethylidyne-producing route must be considered, with the fundamental uncovering that at the reaction exhibits characteristics consistent with structure sensitivity, in contrast to the structure insensitivity found for larger particles. In this size-regime, the chemical properties can be modulated and tuned by a single atom, reflected by the onset of low temperature hydrogenation at T > 150 K catalyzed by Ptn (n ≥ 10) clusters, with maximum room temperature reactivity observed for Pt13 using a pulsed molecular beam technique. Structure insensitive behavior, inherent for specific cluster sizes at ambient temperatures, can be induced in the more active sizes, e.g. Pt13, by a temperature increase, up to 400 K, which opens dehydrogenation channels leading to ethylidyne formation. This reaction channel was, however found to be attenuated on Pt20, as catalyst activity remained elevated after the 400 K step. Pt30 displayed behavior which can be understood from extrapolating bulk properties to this size range; in particular the calculated d-band center. In the non-scalable sub-nanometer size regime, however, precise control of particle size may be used for atom-by-atom tuning and manipulation of catalyzed hydrogenation activity and selectivity.

Theoretical study and simulation for a nanometer laser based on Gauss–Hermite source expansion

International Nuclear Information System (INIS)

Gu, Xiaowei

2013-01-01

Recently there has been worldwide interest in constructing a new generation of continuously tunable nanometer lasers for a wide range of scientific applications, including femtosecond science, biological molecules, nanoscience research fields, etc. The high brightness electron beam required by a short wavelength self-amplified spontaneous emission FEL can be reached only with accurate control of the beam dynamics in the facility. Numerical simulation codes are basic tools for designing new nanometer laser devices. We have developed a MATLAB quasi-one-dimensional code based on a reduced model for the FEL. The model uses an envelope description of the transverse dynamics of the laser beam and full longitudinal particle motion. We have optimized the LCLS facility parameters, then given the characteristics of the nanometer laser. (letter)

Theoretical study and simulation for a nanometer laser based on Gauss-Hermite source expansion

Science.gov (United States)

Gu, Xiaowei

2013-07-01

Recently there has been worldwide interest in constructing a new generation of continuously tunable nanometer lasers for a wide range of scientific applications, including femtosecond science, biological molecules, nanoscience research fields, etc. The high brightness electron beam required by a short wavelength self-amplified spontaneous emission FEL can be reached only with accurate control of the beam dynamics in the facility. Numerical simulation codes are basic tools for designing new nanometer laser devices. We have developed a MATLAB quasi-one-dimensional code based on a reduced model for the FEL. The model uses an envelope description of the transverse dynamics of the laser beam and full longitudinal particle motion. We have optimized the LCLS facility parameters, then given the characteristics of the nanometer laser.

Producing laminated NiAl with bimodal distribution of grain size by solid–liquid reaction treatment

DEFF Research Database (Denmark)

Fan, G.H.; Wang, Q.W.; Du, Y.

2014-01-01

The prospect of combining laminated structure design and grain size tailoring to toughen brittle materials is examined. Laminated NiAl consisting of coarse-grained layers and fine-grained layers was fabricated by solid–liquid reaction treatment of stacking Ni and Al foils. The fracture toughness...

Shearing Nanometer-Thick Confined Hydrocarbon Films: Friction and Adhesion

DEFF Research Database (Denmark)

Sivebæk, I. M.; Persson, B. N. J.

2016-01-01

We present molecular dynamics (MD) friction and adhesion calculations for nanometer-thick confined hydrocarbon films with molecular lengths 20, 100 and 1400 carbon atoms. We study the dependency of the frictional shear stress on the confining pressure and sliding speed. We present results...

Resolving amorphous solid-liquid interfaces by atomic force microscopy

International Nuclear Information System (INIS)

Burson, Kristen M.; Gura, Leonard; Kell, Burkhard; Büchner, Christin; Lewandowski, Adrian L.; Heyde, Markus; Freund, Hans-Joachim

2016-01-01

Recent advancements in liquid atomic force microscopy make it an ideal technique for probing the structure of solid-liquid interfaces. Here, we present a structural study of a two-dimensional amorphous silica bilayer immersed in an aqueous solution utilizing liquid atomic force microscopy with sub-nanometer resolution. Structures show good agreement with atomically resolved ultra-high vacuum scanning tunneling microscopy images obtained on the same sample system, owing to the structural stability of the silica bilayer and the imaging clarity from the two-dimensional sample system. Pair distance histograms of ring center positions are utilized to develop quantitative metrics for structural comparison, and the physical origin of pair distance histogram peaks is addressed by direct assessment of real space structures.

Surface modification and characterization for dispersion stability of inorganic nanometer-scaled particles in liquid media

International Nuclear Information System (INIS)

Kamiya, Hidehiro; Iijima, Motoyuki

2010-01-01

Inorganic nanoparticles are indispensable for science and technology as materials, pigments and cosmetics products. Improving the dispersion stability of nanoparticles in various liquids is essential for those applications. In this review, we discuss why it is difficult to control the stability of nanoparticles in liquids. We also overview the role of surface interaction between nanoparticles in their dispersion and characterization, e.g. by colloid probe atomic force microscopy (CP-AFM). Two types of surface modification concepts, post-synthesis and in situ modification, were investigated in many previous studies. Here, we focus on post-synthesis modification using adsorption of various kinds of polymer dispersants and surfactants on the particle surface, as well as surface chemical reactions of silane coupling agents. We discuss CP-AFM as a technique to analyze the surface interaction between nanoparticles and the effect of surface modification on the nanoparticle dispersion in liquids. (topical review)

Surface modification and characterization for dispersion stability of inorganic nanometer-scaled particles in liquid media

Directory of Open Access Journals (Sweden)

Hidehiro Kamiya and Motoyuki Iijima

2010-01-01

Full Text Available Inorganic nanoparticles are indispensable for science and technology as materials, pigments and cosmetics products. Improving the dispersion stability of nanoparticles in various liquids is essential for those applications. In this review, we discuss why it is difficult to control the stability of nanoparticles in liquids. We also overview the role of surface interaction between nanoparticles in their dispersion and characterization, e.g. by colloid probe atomic force microscopy (CP-AFM. Two types of surface modification concepts, post-synthesis and in situ modification, were investigated in many previous studies. Here, we focus on post-synthesis modification using adsorption of various kinds of polymer dispersants and surfactants on the particle surface, as well as surface chemical reactions of silane coupling agents. We discuss CP-AFM as a technique to analyze the surface interaction between nanoparticles and the effect of surface modification on the nanoparticle dispersion in liquids.

Effect of particle size on laser-induced breakdown spectroscopy analysis of alumina suspension in liquids

Energy Technology Data Exchange (ETDEWEB)

Diaz Rosado, Jose Carlos [CEA, DEN, SEARS, LANIE, 91191 Gif-sur-Yvette (France); Univ. Paris Sud, Faculty of Pharmaceutical Sciences, Public Health and Environment UMR 8079, 5 rue J.B. Clement, 92296 Chatenay-Malabry (France); National University of Engineering, Faculty of Science, P.O. Box 31-139, Av. Tupac Amaru 210, Lima (Peru); L' hermite, Daniel, E-mail: daniel.lhermite@cea.fr [CEA, DEN, SEARS, LANIE, 91191 Gif-sur-Yvette (France); Levi, Yves [Univ. Paris Sud, Faculty of Pharmaceutical Sciences, Public Health and Environment UMR 8079, 5 rue J.B. Clement, 92296 Chatenay-Malabry (France)

2012-08-15

The analysis by Laser Induced Breakdown Spectroscopy (LIBS) was proposed for the detection and the quantification of different elements in water even when the analyte is composed of particles in suspension. We have studied the effect of particle size on the LIBS signal during liquid analysis. In our study we used different particle sizes (from 2 {mu}m to 90 {mu}m) of Al{sub 2}O{sub 3} in suspension in water. The results were compared to the signal obtained in the case of dissolved aluminum. In the case of particles, a linear correlation between the LIBS signal versus concentration was found but a significant decrease in the slope of the calibration curve was found when the particle size increased. Several hypotheses have been tested and only a partial ablation of the particles might explain this decrease in signal intensity. This effect probably does not occur at smaller particle size. We estimated 860 nm/pulse as ablated thickness from the top of the particle. A statistical analysis over all data obtained allowed us to calculate 100 {mu}m as ablated water column depth. - Highlights: Black-Right-Pointing-Pointer We have identified a decrease of calibration curve when particle size increases. Black-Right-Pointing-Pointer Partial particle ablation has been identified as the origin of this effect. Black-Right-Pointing-Pointer The ablation rate on Al{sub 2}O{sub 3} particles in suspension in water has been estimated. Black-Right-Pointing-Pointer We can determine the deepness of the interaction volume into the liquid.

Electromagnetic fields of Nanometer electromagnetic waves and X-ray. New frontiers of electromagnetic wave engineering

International Nuclear Information System (INIS)

2009-01-01

The investigating committee aimed at research on electromagnetic fields in functional devices and X-ray fibers for efficient coherent X-ray generation and their material science, high-precision manufacturing, X-ray microscope, application to medical and information communication technologies, such as interaction between material and nanometer electromagnetic waves of radiated light and X-ray, interaction between microwaves and particle beams, theory and design of high-frequency waveguides for resonator and accelerator, from January 2003 to December 2005. In this report, we describe our research results, in particular, on the topics of synchrotron radiation and Cherenkov radiation, Kyushu synchrotron light source and its technology, nanometer electromagnetic fields in optical region, process of interaction between evanescent waves and near-field light, orthogonal relation of electromagnetic fields including evanescent waves in dispersive dielectrics, optical amplification using electron beam, nanometer electromagnetic fields in focusing waveguide lens device with curved facets, electromagnetic fields in nanometer photonic crystal waveguide consisting of atoms, X-ray scattering and absorption I bio-material for image diagnosis. (author)

Pseudopotential-based electron quantum transport: Theoretical formulation and application to nanometer-scale silicon nanowire transistors

Energy Technology Data Exchange (ETDEWEB)

Fang, Jingtian, E-mail: jingtian.fang@utdallas.edu; Vandenberghe, William G.; Fu, Bo; Fischetti, Massimo V. [Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080 (United States)

2016-01-21

We present a formalism to treat quantum electronic transport at the nanometer scale based on empirical pseudopotentials. This formalism offers explicit atomistic wavefunctions and an accurate band structure, enabling a detailed study of the characteristics of devices with a nanometer-scale channel and body. Assuming externally applied potentials that change slowly along the electron-transport direction, we invoke the envelope-wavefunction approximation to apply the open boundary conditions and to develop the transport equations. We construct the full-band open boundary conditions (self-energies of device contacts) from the complex band structure of the contacts. We solve the transport equations and present the expressions required to calculate the device characteristics, such as device current and charge density. We apply this formalism to study ballistic transport in a gate-all-around (GAA) silicon nanowire field-effect transistor with a body-size of 0.39 nm, a gate length of 6.52 nm, and an effective oxide thickness of 0.43 nm. Simulation results show that this device exhibits a subthreshold slope (SS) of ∼66 mV/decade and a drain-induced barrier-lowering of ∼2.5 mV/V. Our theoretical calculations predict that low-dimensionality channels in a 3D GAA architecture are able to meet the performance requirements of future devices in terms of SS swing and electrostatic control.

Grand Canonical Investigation of the Quasi Liquid Layer of Ice: Is It Liquid?

Science.gov (United States)

Pickering, Ignacio; Paleico, Martin; Sirkin, Yamila A Perez; Scherlis, Damian A; Factorovich, Matías H

2018-05-10

In this study, the solid-vapor equilibrium and the quasi liquid layer (QLL) of ice Ih exposing the basal and primary prismatic faces were explored by means of grand canonical molecular dynamics simulations with the monatomic mW potential. For this model, the solid-vapor equilibrium was found to follow the Clausius-Clapeyron relation in the range examined, from 250 to 270 K, with a Δ H sub of 50 kJ/mol in excellent agreement with the experimental value. The phase diagram of the mW model was constructed for the low pressure region around the triple point. The analysis of the crystallization dynamics during condensation and evaporation revealed that, for the basal face, both processes are highly activated, and in particular cubic ice is formed during condensation, producing stacking-disordered ice. The basal and primary prismatic surfaces of ice Ih were investigated at different temperatures and at their corresponding equilibrium vapor pressures. Our results show that the region known as QLL can be interpreted as the outermost layers of the solid where a partial melting takes place. Solid islands in the nanometer length scale are surrounded by interconnected liquid areas, generating a bidimensional nanophase segregation that spans throughout the entire width of the outermost layer even at 250 K. Two approaches were adopted to quantify the QLL and discussed in light of their ability to reflect this nanophase segregation phenomena. Our results in the μVT ensemble were compared with NPT and NVT simulations for two system sizes. No significant differences were found between the results as a consequence of model system size or of the working ensemble. Nevertheless, certain advantages of performing μVT simulations in order to reproduce the experimental situation are highlighted. On the one hand, the QLL thickness measured out of equilibrium might be affected because of crystallization being slower than condensation. On the other, preliminary simulations of AFM

Flow cell coupled dynamic light scattering for real-time monitoring of nanoparticle size during liquid phase bottom-up synthesis

NARCIS (Netherlands)

Meulendijks, N.; van Ee, R.; Stevens, R.; Mourad, M.; Verheijen, M.A.; Kambly, N.; Armenta, R.; Buskens, P.

2018-01-01

To tailor the properties of nanoparticles and nanocomposites, precise control over particle size is of vital importance. Real-time monitoring of particle size during bottom-up synthesis in liquids would allow a detailed study of particle nucleation and growth, which provides valuable insights in the

Study of 'liquid gold' coatings: Thermal decomposition and formation of metallic thin films

Energy Technology Data Exchange (ETDEWEB)

Deram, V. [Laboratoire de Spectrochimie Infrarouge et Raman, Universite des Sciences et Technologies de Lille, UMR CNRS 8516, Bat C5 - 59655 Villeneuve d' Ascq (France) and Ecole Nationale Superieure des Mines de Paris, Centre de Mise en Forme des Materiaux, UMR CNRS 7635, BP 207, 06904 Sophia-Antipolis (France)]. E-mail: virginie.deram@ensmp.fr; Turrell, S. [Laboratoire de Spectrochimie Infrarouge et Raman, Universite des Sciences et Technologies de Lille, UMR CNRS 8516, Bat C5 - 59655 Villeneuve d' Ascq (France); Darque-Ceretti, E. [Ecole Nationale Superieure des Mines de Paris, Centre de Mise en Forme des Materiaux, UMR CNRS 7635, BP 207, 06904 Sophia-Antipolis (France); Aucouturier, M. [Centre de Recherche et de Restauration des Musees de France, UMR CNRS 171, Palais du Louvre, Porte des Lions, 14 quai F. Mitterrand, 75001 Paris Cedex (France)

2006-09-25

Organo-metallic solutions called liquid gold are largely used to obtain thin gilded films which are employed for decorative, technological and functional uses. However, these films often prove to be fragile with respect to use, resulting in loss of brilliance or even eventual film removal. An understanding of the behaviour of the layers requires good knowledge of the materials themselves. The present work was undertaken to better understand the evolution of the structural properties of liquid gold as it undergoes heat-processing. Accordingly, we followed the thermal decomposition processes of liquid gold coatings and the formation of the gilded metal layer using a combination of experimental techniques. First, thermal analyses coupled with mass spectrometry and infrared spectroscopy gave information concerning the decomposition of the organic medium. It has been found that the process of film formation can be decomposed into three steps, the second of which is an abrupt transition between 300 and 350 deg. C. Details on this transition have been obtained using real-time X-ray Diffraction and Rutherford Backscattering Spectrometry. Above 350 deg. C, the microstructure of the coating is reorganized to obtain a final layer which contains particles, of the size of a few hundreds nanometers, as shown by Transmission Electron Microscopy.

Mechanism and Prediction of Gas Permeation through Sub-Nanometer Graphene Pores: Comparison of Theory and Simulation.

Science.gov (United States)

Yuan, Zhe; Govind Rajan, Ananth; Misra, Rahul Prasanna; Drahushuk, Lee W; Agrawal, Kumar Varoon; Strano, Michael S; Blankschtein, Daniel

2017-08-22

Due to its atomic thickness, porous graphene with sub-nanometer pore sizes constitutes a promising candidate for gas separation membranes that exhibit ultrahigh permeances. While graphene pores can greatly facilitate gas mixture separation, there is currently no validated analytical framework with which one can predict gas permeation through a given graphene pore. In this work, we simulate the permeation of adsorptive gases, such as CO 2 and CH 4 , through sub-nanometer graphene pores using molecular dynamics simulations. We show that gas permeation can typically be decoupled into two steps: (1) adsorption of gas molecules to the pore mouth and (2) translocation of gas molecules from the pore mouth on one side of the graphene membrane to the pore mouth on the other side. We find that the translocation rate coefficient can be expressed using an Arrhenius-type equation, where the energy barrier and the pre-exponential factor can be theoretically predicted using the transition state theory for classical barrier crossing events. We propose a relation between the pre-exponential factor and the entropy penalty of a gas molecule crossing the pore. Furthermore, on the basis of the theory, we propose an efficient algorithm to calculate CO 2 and CH 4 permeances per pore for sub-nanometer graphene pores of any shape. For the CO 2 /CH 4 mixture, the graphene nanopores exhibit a trade-off between the CO 2 permeance and the CO 2 /CH 4 separation factor. This upper bound on a Robeson plot of selectivity versus permeance for a given pore density is predicted and described by the theory. Pores with CO 2 /CH 4 separation factors higher than 10 2 have CO 2 permeances per pore lower than 10 -22 mol s -1 Pa -1 , and pores with separation factors of ∼10 have CO 2 permeances per pore between 10 -22 and 10 -21 mol s -1 Pa -1 . Finally, we show that a pore density of 10 14 m -2 is required for a porous graphene membrane to exceed the permeance-selectivity upper bound of polymeric

Some Issues in Liquid Metals Research

Directory of Open Access Journals (Sweden)

Maria José Caturla

2015-11-01

Full Text Available The ten articles [1–10] included in this Special Issue on “Liquid Metals” do not intend to comprehensively cover this extensive field, but, rather, to highlight recent discoveries that have greatly broadened the scope of technological applications of these materials. Improvements in understanding the physics of liquid metals are, to a large extent, due to the powerful theoretical tools in the hands of scientists, either semi-empirical [1,5,6] or ab initio (molecular dynamics, see [7]. Surface tension and wetting at metal/ceramic interfaces is an everlasting field of fundamental research with important technological implications. The review of [2] is broad enough, as the work carried out at Grenoble covers almost all interesting matters in the field. Some issues of interest in geophysics and astrophysics are discussed in [3]. The recently discovered liquid–liquid transition in several metals is dealt with in [4]. The fifth contribution [5] discusses the role of icosahedral superclusters in crystallization. In [6], thermodynamic calculations are carried out to identify the regions of the ternary phase diagram of Al-Cu-Y, where the formation of amorphous alloys is most probable. Experimental data and ab initio calculations are presented in [7] to show that an optimal microstructure is obtained if Mg is added to the Al-Si melt before than the modifier AlP alloy. Shock-induced melting of metals by means of laser driven compression is discussed in [8]. With respect to recent discoveries, one of the most outstanding developments is that of gallium alloys that are liquid at room temperature [9], and that, due to the oxide layer that readily cover their surface, maintain some “stiffness”. This has opened the possibility of 3D printing with liquid metals. The last article in this Special Issue [10] describes nano-liquid metals, a suspension of liquid metal and its alloy containing nanometer-sized particles. A room-temperature nano-liquid metal

Active liquid-like behavior of nucleoli determines their size and shape in Xenopus laevis oocytes.

Science.gov (United States)

Brangwynne, Clifford P; Mitchison, Timothy J; Hyman, Anthony A

2011-03-15

For most intracellular structures with larger than molecular dimensions, little is known about the connection between underlying molecular activities and higher order organization such as size and shape. Here, we show that both the size and shape of the amphibian oocyte nucleolus ultimately arise because nucleoli behave as liquid-like droplets of RNA and protein, exhibiting characteristic viscous fluid dynamics even on timescales of Nucleoli exhibit a broad distribution of sizes with a characteristic power law, which we show is a consequence of spontaneous coalescence events. These results have implications for the function of nucleoli in ribosome subunit processing and provide a physical link between activity within a macromolecular assembly and its physical properties on larger length scales.

Ionic Liquids with Symmetric Diether Tails: Bulk and Vacuum-Liquid Interfacial Structures.

Science.gov (United States)

Hettige, Jeevapani J; Amith, Weththasinghage D; Castner, Edward W; Margulis, Claudio J

2017-01-12

The behavior in the bulk and at interfaces of biphilic ionic liquids in which either the cation or anion possesses moderately long alkyl tails is to a significant degree well understood. Less clear is what happens when both the cation and anion possess tails that are not apolar, such as in the case of ether functionalities. The current article discusses the structural characteristics of C2OC2OC2-mim + /C2OC2OC2-OSO 3 - in the bulk and at the vacuum interface. We find that the vacuum interface affects only the nanometer length scale. This is in contrast to what we have recently found in ( J. Phys. Chem. Lett. , 2016 , 7 ( 19 ), 3785 - -3790 ) for isoelectronic C[8]-mim + /C[8]-OSO 3 - , where the interface effect is long ranged. Interestingly, ions with the diether tail functionality still favor the tail-outward orientation at the vacuum interface and the bulk phase preserves the alternation between charged networks and tails that is commonly observed for biphilic ionic liquids. However, such alternation is less well-defined and results in a significantly diminished first sharp diffraction peak in the bulk liquid structure function.

Semi-empirical formula for large pore-size estimation from o-Ps annihilation lifetime

International Nuclear Information System (INIS)

Nguyen Duc Thanh; Tran Quoc Dung; Luu Anh Tuyen; Khuong Thanh Tuan

2007-01-01

The o-Ps annihilation rate in large pore was investigated by the semi-classical approach. The semi-empirical formula that simply correlates between the pore size and the o-Ps lifetime was proposed. The calculated results agree well with experiment in the range from some angstroms to several ten nanometers size of pore. (author)

Effect of nanometer scale surface roughness of titanium for osteoblast function

Directory of Open Access Journals (Sweden)

Satoshi Migita

2017-02-01

Full Text Available Surface roughness is an important property for metallic materials used in medical implants or other devices. The present study investigated the effects of surface roughness on cellular function, namely cell attachment, proliferation, and differentiation potential. Titanium (Ti discs, with a hundred nanometer- or nanometer-scale surface roughness (rough and smooth Ti surface, respectively were prepared by polishing with silicon carbide paper. MC3T3-E1 mouse osteoblast-like cells were cultured on the discs, and their attachment, spreading area, proliferation, and calcification were analyzed. Cells cultured on rough Ti discs showed reduced attachment, proliferation, and calcification ability suggesting that the surface inhibited osteoblast function. The findings can provide a basis for improving the biocompatibility of medical devices.

The impact of liquidity and size premium on equity price formation in Serbia

Directory of Open Access Journals (Sweden)

Minović Jelena

2012-01-01

Full Text Available The goal of this paper is to examine the impact of an overall market factor, the factor related to the firm size, the factor related to the ratio of book to market value of companies, and the factor of liquidity risk on expected asset returns in the Serbian market. For this market we estimated different factor models: Capital Asset Pricing Model (CAPM by Sharpe, 1964, Fama-French (FF model (1992, 1993, Liquidity-augmented CAPM (LCAPM by Liu (2006, and combination LCAPM with FF factors. We used daily data for the period from 2005 to 2009. Using a demanding methodology and complex dataset, we found that liquidity and firm size had a significant impact on equity price formation in Serbia. On the other hand, our results suggest that the factor related to the ratio of book to market value of companies does not have an important role in asset pricing in Serbia. We found that Liu’s two factor LCAPM model performs better in explaining stock returns than the standard CAPM and the Fama-French three factor model. Additionally, Liu’s LCAPM may indeed be a good tool for realistic assessment of the expected asset returns. The combination of the Fama-French model and the LCAPM could improve the understanding of equilibrium in the Serbian equity market. Even though previous papers have mostly dealt with examining different factor models of developed or emerging markets worldwide, none of them has tested factor models on the countries of former Yugoslavia. This paper is the first to test the FF model and LCAPM with FF factors in the case of Serbia and the area of ex-Yugoslavia. [Projekat Ministarstva nauke Republike Srbije, br. 179015: Challenges and Prospects of Structural Changes in Serbia: Strategic Directions for Economic Development and Harmonization With EU Requirements

Imaging Action Potential in Single Mammalian Neurons by Tracking the Accompanying Sub-Nanometer Mechanical Motion.

Science.gov (United States)

Yang, Yunze; Liu, Xian-Wei; Wang, Hui; Yu, Hui; Guan, Yan; Wang, Shaopeng; Tao, Nongjian

2018-03-28

Action potentials in neurons have been studied traditionally by intracellular electrophysiological recordings and more recently by the fluorescence detection methods. Here we describe a label-free optical imaging method that can measure mechanical motion in single cells with a sub-nanometer detection limit. Using the method, we have observed sub-nanometer mechanical motion accompanying the action potential in single mammalian neurons by averaging the repeated action potential spikes. The shape and width of the transient displacement are similar to those of the electrically recorded action potential, but the amplitude varies from neuron to neuron, and from one region of a neuron to another, ranging from 0.2-0.4 nm. The work indicates that action potentials may be studied noninvasively in single mammalian neurons by label-free imaging of the accompanying sub-nanometer mechanical motion.

Structure and electrochemical properties of nanometer Cu substituted α-nickel hydroxide

Energy Technology Data Exchange (ETDEWEB)

Bao, Jie [School of Physics and Optoelectronic Engineering, Guangdong University of Technology, WaiHuan Xi Road, No. 100, Guangzhou 510006, Guangdong Province (China); Zhu, Yanjuan, E-mail: YanJuanZhu007@126.com [School of Physics and Optoelectronic Engineering, Guangdong University of Technology, WaiHuan Xi Road, No. 100, Guangzhou 510006, Guangdong Province (China); Zhang, Zhongju [Guangzhou Tiger Head Battery Group Co., Ltd., 568 Huangpu Road, Guangzhou 510655, Guangdong Province (China); Xu, Qingsheng; Zhao, Weiren [School of Physics and Optoelectronic Engineering, Guangdong University of Technology, WaiHuan Xi Road, No. 100, Guangzhou 510006, Guangdong Province (China); Chen, Jian [Instrumentation Analysis and Research Center, Sun Yat-sen University, Guangzhou 510275, Guangdong Province (China); Zhang, Wei; Han, Quanyong [School of Physics and Optoelectronic Engineering, Guangdong University of Technology, WaiHuan Xi Road, No. 100, Guangzhou 510006, Guangdong Province (China)

2013-02-15

Graphical abstract: Display Omitted Highlights: ► Cu substituted α-nickel hydroxide was prepared by ultrasonic assisted precipitation. ► The XRD peaks are anisotropic broadening. ► The electrode for 0.9 wt.% Cu has the highest capacity of 310 mAh/g at 0.2 C. -- Abstract: Nanometer Cu-substituted α-nickel hydroxide was synthesized by means of ultrasonic-assisted precipitation. Particle size distribution (PSD) measurement, X-ray diffraction (XRD), and high-resolution transmission electron microscope (HR-TEM) were used to characterize the physical properties of the synthesized samples. The results indicate that the average particle size of the samples is about 96–110 nm and the XRD diffraction peaks are anisotropic broadening. The crystal grains are mainly polycrystal structure with columnar or needle-like morphology, containing many defects. With increase of Cu content, the shape of primary particles transform from columnar to needle-like. The influences of doping amounts of Cu on the electrochemical performance were investigated through constant current charge/discharge and cyclic voltammetric measurements. The specific capacity increases initially and then decreases with increasing Cu-doping ratio, the electrode C containing 0.9 wt.% Cu shows the maximum discharge capacity of 310 mAh/g at 0.2 C, and it has the lowest charging voltage, higher discharge voltage plateau, better cycle performance and larger proton diffusion coefficient than the other electrodes.

Local mechanical spectroscopy with nanometer-scale lateral resolution

Science.gov (United States)

Oulevey, F.; Gremaud, G.; Sémoroz, A.; Kulik, A. J.; Burnham, N. A.; Dupas, E.; Gourdon, D.

1998-05-01

A new technique has been developed to probe the viscoelastic and anelastic properties of submicron phases of inhomogeneous materials. The measurement gives information related to the internal friction and to the variations of the dynamic modulus of nanometer-sized volumes. It is then the nanoscale equivalent to mechanical spectroscopy, a well-known macroscopic technique for materials studies, also sometimes called dynamic mechanical (thermal) analysis. The technique is based on a scanning force microscope, using the principle of scanning local-acceleration microscopy (SLAM), and allows the sample temperature to be changed. It is called variable-temperature SLAM, abbreviated T-SLAM. According to a recent proposition to systematize names of scanning probe microscope based methods, this technique should be included in the family of "mechanothermal analysis with scanning microscopy." It is suited for studying defect dynamics in nanomaterials and composites by locating the dissipative mechanisms in submicron phases. The primary and secondary relaxations, as well as the viscoplasticity, were observed in bulk PVC. The wide range of phenomena demonstrate the versatility of the technique. A still unexplained increase of the stiffness with increasing temperature was observed just below the glass transition. All of these observations, although their interpretation in terms of physical events is still tentative, are in agreement with global studies. This technique also permits one to image the variations of the local elasticity or of the local damping at a fixed temperature. This enables the study of, for instance, the homogeneity of phase transitions in multiphased materials, or of the interface morphologies and properties. As an illustration, the homogeneity of the glass transition temperature of PVC in a 50/50 wt % PVC/PB polymer blend has been demonstrated. Due to the small size of the probed volume, T-SLAM gives information on the mechanical properties of the near

Surface enhanced Raman scattering of gold nanoparticles supported on copper foil with graphene as a nanometer gap

International Nuclear Information System (INIS)

Xiang, Quan; Zhu, Xupeng; Chen, Yiqin; Duan, Huigao

2016-01-01

Gaps with single-nanometer dimensions (<10 nm) between metallic nanostructures enable giant local field enhancements for surface enhanced Raman scattering (SERS). Monolayer graphene is an ideal candidate to obtain a sub-nanometer gap between plasmonic nanostructures. In this work, we demonstrate a simple method to achieve a sub-nanometer gap by dewetting a gold film supported on monolayer graphene grown on copper foil. The Cu foil can serve as a low-loss plasmonically active metallic film that supports the imaginary charge oscillations, while the graphene can not only create a stable sub-nanometer gap for massive plasmonic field enhancements but also serve as a chemical enhancer. We obtained higher SERS enhancements in this graphene-gapped configuration compared to those in Au nanoparticles on Cu film or on graphene–SiO 2 –Si. Also, the Raman signals measured maintained their fine features and intensities over a long time period, indicating the stability of this Au–graphene–Cu hybrid configuration as an SERS substrate. (paper)

A system for aerodynamically sizing ultrafine environmental radioactive particles

International Nuclear Information System (INIS)

Olawoyin, L.

1995-09-01

The unattached environmental radioactive particles/clusters, produced mainly by 222 Rn in indoor air, are usually few nanometers in size. The inhalation of these radioactive clusters can lead to deposition of radioactivity on the mucosal surface of the tracheobronchial tree. The ultimate size of the cluster together with the flow characteristics will determine the depositional site in the human lung and thus, the extent of damage that can be caused. Thus, there exists the need for the determination of the size of the radioactive clusters. However, the existing particle measuring device have low resolution in the sub-nanometer range. In this research, a system for the alternative detection and measurement of the size of particles/cluster in the less than 2 nm range have been developed. The system is a one stage impactor which has a solid state spectrometer as its impaction plate. It's major feature is the nozzle-to-plate separation, L. The particle size collected changes with L and thus, particle size spectroscopy is achieved by varying L. The number of collected particles is determined by alpha spectroscopy. The size-discriminating ability of the system was tested with laboratory generated radon particles and it was subsequently used to characterize the physical (size) changes associated with the interaction of radon progeny with water vapor and short chain alcohols in various support gases. The theory of both traditional and high velocity jet impactors together with the design and evaluation of the system developed in this study are discussed in various chapters of this dissertation. The major results obtained in the course of the study are also presented

A system for aerodynamically sizing ultrafine environmental radioactive particles

Energy Technology Data Exchange (ETDEWEB)

Olawoyin, L.

1995-09-01

The unattached environmental radioactive particles/clusters, produced mainly by {sup 222}Rn in indoor air, are usually few nanometers in size. The inhalation of these radioactive clusters can lead to deposition of radioactivity on the mucosal surface of the tracheobronchial tree. The ultimate size of the cluster together with the flow characteristics will determine the depositional site in the human lung and thus, the extent of damage that can be caused. Thus, there exists the need for the determination of the size of the radioactive clusters. However, the existing particle measuring device have low resolution in the sub-nanometer range. In this research, a system for the alternative detection and measurement of the size of particles/cluster in the less than 2 nm range have been developed. The system is a one stage impactor which has a solid state spectrometer as its impaction plate. It`s major feature is the nozzle-to-plate separation, L. The particle size collected changes with L and thus, particle size spectroscopy is achieved by varying L. The number of collected particles is determined by alpha spectroscopy. The size-discriminating ability of the system was tested with laboratory generated radon particles and it was subsequently used to characterize the physical (size) changes associated with the interaction of radon progeny with water vapor and short chain alcohols in various support gases. The theory of both traditional and high velocity jet impactors together with the design and evaluation of the system developed in this study are discussed in various chapters of this dissertation. The major results obtained in the course of the study are also presented.

A study of interaction effect theoretical with combination size grain on magnetics in of permanent magnet

International Nuclear Information System (INIS)

Tarihoran, Doansi; Manaf, Azwar

2002-01-01

Stoner-Wohlfarth theory, SW shows a deviation around 30-40% to the measurement result of a permanent magnetic material with nanometer-sized grains. This is caused by this theory neglecting the interacting grain factor. This research modifies SW theory by calculating the grain interacting effect. The modification is made by assuming the interacting energy of a mono-domain grain has ellipsoidal shaped focused at the edge of the grain. SW grain in this calculation model is a box-shaped in a grain with edges of the box placed in the skin's grain. The result shows that interacting effect make remanent polarization increasing drastically and coercive field value decreasing when grain's size reaches 20% of size of the first mono-domain grain. For material with ND 2 Fe 14 B phase, the optimum coercive field value and remanent polarization that producing maximum product energy, (BH) m ax obtained in a material with 5 nanometer-size grains. Qualitatively there is as appropriate result between the calculation and measurement

Influence of plasmon coupling on the photoluminescence of ZnS/Ag nanoparticles obtained by laser irradiation in liquid

Science.gov (United States)

Moos, Rafaela; Graff, Ismael L.; de Oliveira, Vinicius S.; Schreiner, Wido H.; Bezerra, Arandi G.

2017-10-01

We investigate the photoluminescence, optical absorption and structural properties of ZnS submitted to laser irradiation in water and isopropyl alcohol. Nanoparticles were produced by irradiating micro-sized ZnS particles dispersed in both liquids, with and without the addition of Ag nanoparticles, taking advantage of the laser-assisted fragmentation effect. When ZnS microparticles are irradiated either in pure water or isopropyl alcohol a considerable size reduction is achieved (from micra to few nanometers). The photoluminescence of these nanoparticles mainly occurs in the UV, centered at 350 nm, and with smaller intensity in the visible, centered at 600 nm. Irradiation of ZnS microparticles dispersed in colloidal silver triggers a reaction between both materials, modifying its optical absorption and photoluminescent properties. After irradiation of ZnS in alcohol containing Ag nanoparticles, a giant increase of the UV photoluminescence is observed. Interestingly, when the irradiation is performed in aqueous Ag nanoparticles colloids, the photoluminescence suffers a red-shift towards the violet-blue. The data show that core-shell (Ag-ZnO) nanostructures are formed after irradiation and the visible emission likely originates from the ZnO shell grown around silver nanoparticles. The presence of Ag nanoparticles in the liquid medium promotes a stronger absorption of the laser beam during irradiation due to the coupling with the surface plasmon resonance, fostering intense reactions among ZnS, Ag nanoparticles, and the liquid medium. Our study shows that with a simple change of the liquid medium wherein the irradiation is conducted the photoluminescence can be tuned from UV to visible and core-shell nanostructures can be obtained.

Two-dimensional simulation of intermediate-sized bubbles in low viscous liquids using counter diffusion lattice Boltzmann method

Energy Technology Data Exchange (ETDEWEB)

Ryu, Seungyeob, E-mail: syryu@kaeri.re.kr [Korea Atomic Energy Research Institute (KAERI), 1045 Daeduk-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Youngin; Kang, Hanok; Kim, Keung Koo [Korea Atomic Energy Research Institute (KAERI), 1045 Daeduk-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ko, Sungho, E-mail: sunghoko@cnu.ac.kr [Department of Mechanical Design Engineering, Chungnam National University, 220 Gung-dong, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

2016-08-15

Highlights: • We directly simulate intermediate-sized bubbles in low viscous liquids. • The path instability and shape oscillation can be successfully simulated. • The motion of a pair bubble and bubble swarm is presented. • Bubbles with high-Reynolds-number can be simulated with under-resolved grids. • The counter diffusion multiphase method is feasible for the direct simulation of bubbly flows. - Abstract: The counter diffusion lattice Boltzmann method (LBM) is used to simulate intermediate-sized bubbles in low viscous liquids. Bubbles at high Reynolds numbers ranging from hundreds to thousands are simulated successfully, which cannot be done for the existing LBM versions. The characteristics of the path instability of two rising bubbles are studied for a wide range of Eotvos and Morton numbers. Finally, the study presented how bubble swarms move within the flow and how the flow surrounding the bubbles is affected by the bubble motions.

Energy harvesting from organic liquids in micro-sized microbial fuel cells

KAUST Repository

Mink, J.E.

2014-03-07

Micro-sized microbial fuel cells (MFCs) are miniature energy harvesters that use bacteria to convert biomass from liquids into usable power. The key challenge is transitioning laboratory test beds into devices capable of producing high power using readily available fuel sources. Here, we present a pragmatic step toward advancing MFC applications through the fabrication of a uniquely mobile and inexpensive micro-sized device that can be fueled with human saliva. The 25-ll MFC was fabricated with graphene, a two-dimensional atomic crystal-structured material, as an anode for efficient current generation and with an air cathode for enabling the use of the oxygen present in air, making its operation completely mobile and free of the need for laboratory chemicals. With saliva as a fuel, the device produced higher current densities (1190 Am-3) than any previous aircathode micro-sized MFCs. The use of the graphene anode generated 40 times more power than that possible using a carbon cloth anode. Additional tests were performed using acetate, a conventional organic material, at high organic loadings that were comparable to those in saliva, and the results demonstrated a linear relationship between the organic loading and current. These findings open the door to saliva-powered applications of this fuel cell technology for Lab-on-a-Chip devices or portable point-of-care diagnostic devices. 2014 Nature Publishing Group All rights reserved 1884-4057/14.

Liquid-liquid and liquid-solid phase separation and flocculation for a charged colloidal dispersion

International Nuclear Information System (INIS)

Lai, S.K.; Wu, K.L.

2002-01-01

We model the intercolloidal interaction by a hard-sphere Yukawa repulsion to which is added the long-range van der Waals attraction. In comparison with the Derjaguin-Landau-Verwey-Overbeek repulsion, the Yukawa repulsion explicitly incorporates the spatial correlations between colloids and small ions. As a result, the repulsive part can be expressed analytically and has a coupling strength depending on the colloidal volume fraction. By use of this two-body potential of mean force and in conjunction with a second-order thermodynamic perturbation theory, we construct the colloidal Helmholtz free energy and use it to calculate the thermodynamic quantities, pressure and chemical potential, needed in the determination of the liquid-liquid and liquid-solid phase diagrams. We examine, in an aqueous charged colloidal dispersion, the effects of the Hamaker constant and particle size on the conformation of a stable liquid-liquid phase transition calculated with respect to the liquid-solid coexistence phases. We find that there exists a threshold Hamaker constant or particle size whose value demarcates the stable liquid-liquid coexistence phases from their metastable counterparts. Applying the same technique and using the energetic criterion, we extend our calculations to study the flocculation phenomenon in aqueous charged colloids. Here, we pay due attention to determining the loci of a stability curve stipulated for a given temperature T 0 , and obtain the parametric phase diagram of the Hamaker constant vs the coupling strength or, at given surface potential, the particle size. By imposing T 0 to be the critical temperature T c , i.e., setting k B T 0 (=k B T c ) equal to a reasonable potential barrier, we arrive at the stability curve that marks the irreversible reversible phase transition. The interesting result is that there occurs a minimum size for the colloidal particles below (above) which the colloidal dispersion is driven to an irreversible (reversible) phase

Detection based on rainbow refractometry of droplet sphericity in liquid-liquid systems.

Science.gov (United States)

Lohner, H; Lehmann, P; Bauckhage, K

1999-03-01

The shape of droplets in liquid-liquid systems influences their mass and momentum transfer processes. The deviation from sphericity of rising droplets in liquid-liquid systems was investigated for different droplet sizes. Rainbow refractometry permits one to test, in this case, whether the use of laser-optical particle sizing will be correct or faulty. Since the assumption of spherical particle geometry is a general basis of laser-optical particle-sizing techniques such as rainbow refractometry or phase Doppler anemometry, deviation from the spherical shape results in a measuring error. A sphericity check based on rainbow refractometry is introduced.

DNA and ion transport through solid-state nanopores

NARCIS (Netherlands)

Smeets, R.M.M.

2008-01-01

This thesis describes experimental work on a novel type of devices capable of detecting single-(bio)molecules; nanometer-sized pores, or nanopores. Individual nanopores are placed in between two electrolyte-filled liquid compartments and (bio)molecules are electrophoretically driven through them.

Finite size and Coulomb corrections: from nuclei to nuclear liquid vapor phase diagram

International Nuclear Information System (INIS)

Moretto, L.G.; Elliott, J.B.; Phair, L.

2003-01-01

In this paper we consider the problem of obtaining the infinite symmetric uncharged nuclear matter phase diagram from a thermal nuclear reaction. In the first part we shall consider the Coulomb interaction which, because of its long range makes the definition of phases problematic. This Coulomb effect seems truly devastating since it does not allow one to define nuclear phase transitions much above A ∼ 30. However there may be a solution to this difficulty. If we consider the emission of particles with a sizable charge, we notice that a large Coulomb barrier Bc is present. For T << Bc these channels may be considered effectively closed. Consequently the unbound channels may not play a role on a suitably short time scale. Then a phase transition may still be definable in an approximate way. In the second part of the article we shall deal with the finite size problem by means of a new method, the complement method, which shall permit a straightforward extrapolation to the infinite system. The complement approach consists of evaluating the change in free energy occurring when a particle or cluster is moved from one (finite) phase to another. In the case of a liquid drop in equilibrium with its vapor, this is done by extracting a vapor particle of any given size from the drop and evaluating the energy and entropy changes associated with both the vapor particle and the residual liquid drop (complement)

Observation of Shapiro-steps in AFM-plought micron-size YBCO planar construction

CSIR Research Space (South Africa)

Elkaseh, AAO

2009-01-01

Full Text Available Using an Atomic Force Microscope (AFM), micron size planar constriction type junctions was successfully ploughed on YBa2Cu3O7-x thin films. The 100 nanometer (nm) thin films are deposited on MgO substrates by an Inverted Cylindrical Magnetron (ICM...

Thermal and ultrasonic influence in the formation of nanometer scale hydroxyapatite bio-ceramic

Science.gov (United States)

Poinern, GJE; Brundavanam, R; Le, X Thi; Djordjevic, S; Prokic, M; Fawcett, D

2011-01-01

Hydroxyapatite (HAP) is a widely used biocompatible ceramic in many biomedical applications and devices. Currently nanometer-scale forms of HAP are being intensely investigated due to their close similarity to the inorganic mineral component of the natural bone matrix. In this study nano-HAP was prepared via a wet precipitation method using Ca(NO3)2 and KH2PO4 as the main reactants and NH4OH as the precipitator under ultrasonic irradiation. The Ca/P ratio was set at 1.67 and the pH was maintained at 9 during the synthesis process. The influence of the thermal treatment was investigated by using two thermal treatment processes to produce ultrafine nano-HAP powders. In the first heat treatment, a conventional radiant tube furnace was used to produce nano-particles with an average size of approximately 30 nm in diameter, while the second thermal treatment used a microwave-based technique to produce particles with an average diameter of 36 nm. The crystalline structure and morphology of all nanoparticle powders produced were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). Both thermal techniques effectively produced ultrafine powders with similar crystalline structure, morphology and particle sizes. PMID:22114473

ANALYSIS OF EFFECT OF PROFITABILITY, ASSETS STRUCTURE, SIZE OF COMPANIES, AND LIQUIDITY TO CAPITAL STRUCTURES IN MINING COMPANIES LISTED IN INDONESIA STOCK EXCHANGE PERIOD 2012 - 2015

Directory of Open Access Journals (Sweden)

Gatot Nazir Ahmad

2017-09-01

Full Text Available The purpose of this study is to analyze the effect of profitability, structure assets, firm size and liquidity to the capital structure of mining companies listed on the Indonesia Stock Exchange for the period 2012-2015. Sampling technique using purpose sampling. Data analysis technique used in this research is panel data regression. The results showed that partially profitability had negative and significant effect to capital structure, asset structure had positive and significant effect to capital structure, firm size had positive and significant effect to capital structure, and liquidity had negative and significant effect to capital structure. Simultaneously profitability, asset structure, firm size and liquidity have a significant effect on capital structure.

Determination of denaturated proteins and biotoxins by on-line size-exclusion chromatography-digestion-liquid chromatography-electrospray mass spectrometry

NARCIS (Netherlands)

Carol, J.; Gorseling, M.C.J.K.; Jong, C.F. de; Lingeman, H.; Kientz, C.E.; Baar, B.L.M. van; Irth, H.

2005-01-01

A multidimensional analytical method for the rapid determination and identification of proteins has been developed. The method is based on the size-exclusion fractionation of protein-containing samples, subsequent on-line trypsin digestion and desalination, and reversed-phase high-performance liquid

Applied Study on Magnetic Nanometer Beads in Preparation of Genechip Samples

Institute of Scientific and Technical Information of China (English)

陈慧; 高华方; 谢欣; 马雪梅; 杨渝珍

2004-01-01

Summary: A protocol for enrichment and adsorption of karyocyte from whole blood by using magnetic nanometer beads as solid-phase absorbents was presented. The PCR amplification could be accomplished by using the nanobeads with karyocyte as template directly and the PCR products were applied on an oligonucleotide array to do gene typing. The HLA-A PCR amplification system and a small HLA-A oligonucleotide microarray were applied as the platform and an experiment protocol of separating karyocyte from whole blood using the magnetic nanometer beads (Fe2O3) were set up.The experimental conditions were also discussed. It showed that pH level of PBS eluent, Taq enzyme quantity and fragment length of products could influent the amplification results, and the magnetic nano-beads could succeed in sample preparation in microarray to provide a promising way in automatic detection and lab-on-a-chip.

Sampling considerations when analyzing micrometric-sized particles in a liquid jet using laser induced breakdown spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Faye, C.B.; Amodeo, T.; Fréjafon, E. [Institut National de l' Environnement Industriel et des Risques (INERIS/DRC/CARA/NOVA), Parc Technologique Alata, BP 2, 60550 Verneuil-En-Halatte (France); Delepine-Gilon, N. [Institut des Sciences Analytiques, 5 rue de la Doua, 69100 Villeurbanne (France); Dutouquet, C., E-mail: christophe.dutouquet@ineris.fr [Institut National de l' Environnement Industriel et des Risques (INERIS/DRC/CARA/NOVA), Parc Technologique Alata, BP 2, 60550 Verneuil-En-Halatte (France)

2014-01-01

Pollution of water is a matter of concern all over the earth. Particles are known to play an important role in the transportation of pollutants in this medium. In addition, the emergence of new materials such as NOAA (Nano-Objects, their Aggregates and their Agglomerates) emphasizes the need to develop adapted instruments for their detection. Surveillance of pollutants in particulate form in waste waters in industries involved in nanoparticle manufacturing and processing is a telling example of possible applications of such instrumental development. The LIBS (laser-induced breakdown spectroscopy) technique coupled with the liquid jet as sampling mode for suspensions was deemed as a potential candidate for on-line and real time monitoring. With the final aim in view to obtain the best detection limits, the interaction of nanosecond laser pulses with the liquid jet was examined. The evolution of the volume sampled by laser pulses was estimated as a function of the laser energy applying conditional analysis when analyzing a suspension of micrometric-sized particles of borosilicate glass. An estimation of the sampled depth was made. Along with the estimation of the sampled volume, the evolution of the SNR (signal to noise ratio) as a function of the laser energy was investigated as well. Eventually, the laser energy and the corresponding fluence optimizing both the sampling volume and the SNR were determined. The obtained results highlight intrinsic limitations of the liquid jet sampling mode when using 532 nm nanosecond laser pulses with suspensions. - Highlights: • Micrometric-sized particles in suspensions are analyzed using LIBS and a liquid jet. • The evolution of the sampling volume is estimated as a function of laser energy. • The sampling volume happens to saturate beyond a certain laser fluence. • Its value was found much lower than the beam diameter times the jet thickness. • Particles proved not to be entirely vaporized.

Flow transition criteria of a liquid jet into a liquid pool

Energy Technology Data Exchange (ETDEWEB)

Saito, Shimpei, E-mail: s1630195@u.tsukuba.ac.jp [Graduate School of Systems and Information Engineering, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Abe, Yutaka [Faculty of Engineering, Information and Systems, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Koyama, Kazuya [Reactor Core and Safety Design Department, Mitsubishi FBR Systems, Inc., 2-34-17 Jingumae, Shibuya, Tokyo 150-0001 (Japan)

2017-04-15

Highlights: • Jet breakup and droplet formation in immiscible liquid-liquid systems was studied experimentally. • The observed jet breakup behavior was classified into characteristic regimes. • The droplet size distribution was analyzed using image processing. • The variation of droplet size was compared with available melt-jet experiments. • Extrapolation to the expected SFR conditions implied that most of the hydrodynamic conditions would be the atomization regime. - Abstract: To better understand the fundamental interactions between melt jet and coolant during a core-disruptive accident at a sodium-cooled fast reactor, the jet breakup and droplet formation in immiscible liquid-liquid systems were studied experimentally. Experiments using two different pairs of test fluids were carried out at isothermal conditions. The observed jet breakup behavior was classified into characteristic regimes based on the classical Ohnesorge classification in liquid-gas systems. The variation in breakup length obtained in the present liquid-liquid system was similar to that in a liquid-gas system. The droplet size distribution in each breakup regime was analyzed using image processing and droplet formation via pinch-off, satellite formation, and entrainment was observed. The measured droplet size was compared with those available from melt jet experiments. Based on the observation and analysis results, the breakup regimes were organized on a dimensionless operating diagram, with the derived correlations representing the criteria for regime boundaries of a liquid-liquid system. Finally, the experimental data were extrapolated to the expected conditions of a sodium-cooled fast reactor. From this, it was implied that most of the hydrodynamic conditions during an accident would be close to the atomization regime, in which entrainment is the dominant process for droplet formation.

Electrocatalysis of hemoglobin in ionic liquid BMIMPF6 and CuS nanosphere composite films

Directory of Open Access Journals (Sweden)

Wei Sun

2011-12-01

Full Text Available Ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6 was mixed homogeneously with nanometer-sized semiconductor CuS sphere to form a new nanocomposite material, which was further used for the immobilization of hemoglobin (Hb on the surface of carbon paste electrode (CPE. Direct electrochemistry of Hb in BMIMPF6-CuS composite film was carefully investigated with a pair of quasi-reversible redox peaks appeared and the formal potential (E0' was got as -135 mV (vs. SCE in pH 7.0 phosphate buffer solution, which was due to the enhanced direct electron transfer rate of Hb in the biocompatible matrix. The BMIMPF6-CuS-Hb/CPE showed excellent electrocatalytic activity to the reduction of hydrogen peroxide with the kinetic parameters for the electrocatalytic reaction evaluated. The results indicated that the BMIMPF6-CuS nanocomposite could be used for the preparation of electrochemical biosensor.

Bimetallic Ag-Pt Sub-nanometer Supported Clusters as Highly Efficient and Robust Oxidation Catalysts

Energy Technology Data Exchange (ETDEWEB)

Negreiros, Fabio R. [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Halder, Avik [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Yin, Chunrong [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Singh, Akansha [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Barcaro, Giovanni [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Sementa, Luca [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Tyo, Eric C. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Pellin, Michael J. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Bartling, Stephan [Institut für Physik, Universität Rostock, Rostock Germany; Meiwes-Broer, Karl-Heinz [Institut für Physik, Universität Rostock, Rostock Germany; Seifert, Sönke [X-ray Science Division, Argonne National Laboratory, Lemont IL USA; Sen, Prasenjit [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Nigam, Sandeep [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Fukui, Nobuyuki [East Tokyo Laboratory, Genesis Research Institute, Inc., Ichikawa Chiba 272-0001 Japan; Yasumatsu, Hisato [Cluster Research Laboratory, Toyota Technological Institute: in, East Tokyo Laboratory, Genesis Research Institute, Inc. Ichikawa, Chiba 272-0001 Japan; Vajda, Stefan [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Nanoscience and Technology Division, Argonne National Laboratory, Lemont IL USA; Institute for Molecular Engineering, University of Chicago, Chicago IL USA; Fortunelli, Alessandro [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Materials and Process Simulation Center, California Institute of Technology, Pasadena CA USA

2017-12-29

A combined experimental and theoretical investigation of Ag-Pt sub-nanometer clusters as heterogeneous catalysts in the CO -> CO2 reaction (COox) is presented. Ag9Pt2 and Ag9Pt3 clusters are size-selected in the gas phase, deposited on an ultrathin amorphous alumina support, and tested as catalysts experimentally under realistic conditions and by first-principles simulations at realistic coverage. Insitu GISAXS/TPRx demonstrates that the clusters do not sinter or deactivate even after prolonged exposure to reactants at high temperature, and present comparable, extremely high COox catalytic efficiency. Such high activity and stability are ascribed to a synergic role of Ag and Pt in ultranano-aggregates, in which Pt anchors the clusters to the support and binds and activates two CO molecules, while Ag binds and activates O-2, and Ag/Pt surface proximity disfavors poisoning by CO or oxidized species.

Non-equilibrium Green function method: theory and application in simulation of nanometer electronic devices

International Nuclear Information System (INIS)

Do, Van-Nam

2014-01-01

We review fundamental aspects of the non-equilibrium Green function method in the simulation of nanometer electronic devices. The method is implemented into our recently developed computer package OPEDEVS to investigate transport properties of electrons in nano-scale devices and low-dimensional materials. Concretely, we present the definition of the four real-time Green functions, the retarded, advanced, lesser and greater functions. Basic relations among these functions and their equations of motion are also presented in detail as the basis for the performance of analytical and numerical calculations. In particular, we review in detail two recursive algorithms, which are implemented in OPEDEVS to solve the Green functions defined in finite-size opened systems and in the surface layer of semi-infinite homogeneous ones. Operation of the package is then illustrated through the simulation of the transport characteristics of a typical semiconductor device structure, the resonant tunneling diodes. (review)

Mean shear resistance at steady-state for wet glass beads impact of liquid content and particle size

Science.gov (United States)

Louati, Haithem; Oulahna, Driss; de Ryck, Alain

2017-06-01

The flow behaviour of a granular media is due to their weight, frictional contact forces between them, and external forces exerted by the walls. If their size is lower than 50 microns, the Van-der-Waals forces between them may also influence their flowability. When adding some wetting liquid, we introduce attractive forces between the particles, whose order of magnitude may overcome the particle weight and V-d-W interactions. This leads to a cohesive behaviour. The shear stress to start the flow is greater than in the dry case but the steady-state flow is also perturbed by the presence of liquid bridges. This later phenomenon has been recently quantitatively studied for 70-110 μm glass beads with a non-volatile liquid, with experimental results for different normal stresses (up to 12 kPa) and liquid content (up to 20 % in volume). These results have been compared to a heuristic model, based on the model for capillary bridges and the simplest hypothesis for the granular bed texture depending on the stresses applied. We extend this study with new results concerning smaller glass beads 12-40 μm in diameter and larger liquid fraction for 70-110 μm glass beads using experimental and theoretical approaches.

Nanometer-scale patterning of high-Tc superconductors for Josephson junction-based digital circuits

International Nuclear Information System (INIS)

Wendt, J.R.; Plut, T.A.; Corless, R.F.; Martens, J.S.; Berkowitz, S.; Char, K.; Johansson, M.; Hou, S.Y.; Phillips, J.M.

1994-01-01

A straightforward method for nanometer-scale patterning of high-T c superconductor thin films is discussed. The technique combines direct-write electron beam lithography with well-controlled aqueous etches and is applied to the fabrication of Josephson junction nanobridges in high-quality, epitaxial thin-film YBa 2 Cu 3 O 7 . We present the results of our studies of the dimensions, yield, uniformity, and mechanism of the junctions along with the performance of a representative digital circuit based on these junctions. Direct current junction parameter statistics measured at 77 K show critical currents of 27.5 μA±13% for a sample set of 220 junctions. The Josephson behavior of the nanobridge is believed to arise from the aggregation of oxygen vacancies in the nanometer-scale bridge

Analog filters in nanometer CMOS

CERN Document Server

Uhrmann, Heimo; Zimmermann, Horst

2014-01-01

Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

Real-Time Imaging of Plant Cell Wall Structure at Nanometer Scale, with Respect to Cellulase Accessibility and Degradation Kinetics (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Ding, S. Y.

2012-05-01

Presentation on real-time imaging of plant cell wall structure at nanometer scale. Objectives are to develop tools to measure biomass at the nanometer scale; elucidate the molecular bases of biomass deconstruction; and identify factors that affect the conversion efficiency of biomass-to-biofuels.

Radioactive liquid waste filtering device

International Nuclear Information System (INIS)

Inami, Ichiro; Tabata, Masayuki; Kubo, Koji.

1988-01-01

Purpose: To prevent clogging in filter materials and improve the filtration performance for radioactive liquid wastes without increasing the amount of radioactive wastes. Constitution: In a radioactive waste filtering device, a liquid waste recycling pipe and a liquid recycling pump are disposed for recycling the radioactive liquid wastes in a liquid wastes vessel. In this case, the recycling pipe and the recycling pump are properly selected so as to satisfy the conditions capable of making the radioactive liquid wastes flowing through the pipe to have the Reynolds number of 10 4 - 10 5 . By repeating the transportation of radioactive liquid wastes in the liquid waste vessel through the liquid waste recycling pipe by the liquid waste recycling pump and then returning them to the liquid waste vessel again, particles of fine grain size in the suspended liquids are coagulated with each other upon collision to increase the grain size of the suspended particles. In this way, clogging of the filter materials caused by the particles of fine grain size can be prevented, thereby enabling to prevent the increase in the rising rate of the filtration differential pressure, reduce the frequency for the occurrence of radioactive wastes such as filter sludges and improve the processing performance. (Kamimura, M.)

Value Recovery from Waste Liquid Crystal Display Glass Cullet through Leaching: Understanding the Correlation between Indium Leaching Behavior and Cullet Piece Size

OpenAIRE

Basudev Swain; Chan Gi Lee; Hyun Seon Hong

2018-01-01

For hydrometallurgical recovery of indium from glass cullet after dismantling a waste liquid crystal display (LCD), leaching is the rudimentary stage. Though size reduction of the cullet pieces adds convenience for recycling, from an efficiency and cost-effectiveness perspective regarding leaching process development, determining the proper cullet piece size is essential. Hence, in this study, leaching efficiency of indium as a function of cullet piece size was investigated, wherein the prope...

Preparation of nanometer sized Mn doped Zn based oxides powder for DMS applications

CSIR Research Space (South Africa)

Das, J

2009-01-01

Full Text Available In order to study the size dependent DMS (Diluted Magnetic Semiconductor) behavior of Mn doped ZnO, the authors have systematically prepared a series of nanosized green powder based on Mn doped ZnO (Zn 1-x Mn x O, where x=0.02 - 0.1) materials using...

Quantitative nanometer-scale mapping of dielectric tunability

Energy Technology Data Exchange (ETDEWEB)

Tselev, Alexander [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Klein, Andreas [Technische Univ. Darmstadt (Germany); Gassmann, Juergen [Technische Univ. Darmstadt (Germany); Jesse, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Li, Qian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kalinin, Sergei V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wisinger, Nina Balke [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-08-21

Two scanning probe microscopy techniques—near-field scanning microwave microscopy (SMM) and piezoresponse force microscopy (PFM)—are used to characterize and image tunability in a thin (Ba,Sr)TiO3 film with nanometer scale spatial resolution. While sMIM allows direct probing of tunability by measurement of the change in the dielectric constant, in PFM, tunability can be extracted via electrostrictive response. The near-field microwave imaging and PFM provide similar information about dielectric tunability with PFM capable to deliver quantitative information on tunability with a higher spatial resolution close to 15 nm. This is the first time that information about the dielectric tunability is available on such length scales.

Modeling of the evolution of bubble size distribution of gas-liquid flow inside a large vertical pipe. Influence of bubble coalescence and breakup models

International Nuclear Information System (INIS)

Liao, Yixiang; Lucas, Dirk

2011-01-01

The range of gas-liquid flow applications in today's technology is immensely wide. Important examples can be found in chemical reactors, boiling and condensation equipments as well as nuclear reactors. In gas-liquid flows, the bubble size distribution plays an important role in the phase structure and interfacial exchange behaviors. It is therefore necessary to take into account the dynamic change of the bubble size distribution to get good predictions in CFD. An efficient 1D Multi-Bubble-Size-Class Test Solver was introduced in Lucas et al. (2001) for the simulation of the development of the flow structure along a vertical pipe. The model considers a large number of bubble classes. It solves the radial profiles of liquid and gas velocities, bubble-size class resolved gas fraction profiles as well as turbulence parameters on basis of the bubble size distribution present at the given axial position. The evolution of the flow along the height is assumed to be solely caused by the progress of bubble coalescence and break-up resulting in a bubble size distribution changing in the axial direction. In this model, the bubble coalescence and breakup models are very important for reasonable predictions of the bubble size distribution. Many bubble coalescence and breakup models have been proposed in the literature. However, some obvious discrepancies exist in the models; for example, the daughter bubble size distributions are greatly different from different bubble breakup models, as reviewed in our previous publication (Liao and Lucas, 2009a; 2010). Therefore, it is necessary to compare and evaluate typical bubble coalescence and breakup models that have been commonly used in the literature. Thus, this work is aimed to make a comparison of several typical bubble coalescence and breakup models and to discuss in detail the ability of the Test Solver to predict the evolution of bubble size distribution. (orig.)

Dimensional crossover in fluids under nanometer-scale confinement.

Science.gov (United States)

Das, Amit; Chakrabarti, J

2012-05-01

Several earlier studies have shown signatures of crossover in various static and dynamics properties of a confined fluid when the confining dimension decreases to about a nanometer. The density fluctuations govern the majority of such properties of a fluid. Here, we illustrate the crossover in density fluctuation in a confined fluid, to provide a generic understanding of confinement-induced crossover of fluid properties, using computer simulations. The crossover can be understood as a manifestation of changes in the long-wavelength behavior of fluctuation in density due to geometrical constraints. We further show that the confining potential significantly affects the crossover behavior.

Molecular dynamics simulation studies of mid-size liquid n-Alkanes, C12–C160

International Nuclear Information System (INIS)

Kwon, Tae Woo; Lee, Song Hi

2015-01-01

In this study, we report the results of molecular dynamics simulations (MD) for model systems of mid-size liquid n-alkanes (C 12 –C 160 ) at several temperatures (⁓2700 K) in canonical ensembles to calculate structural and dynamic properties (viscosity η, self-diffusion constant D, and monomeric friction constant ζ). For the small n-alkanes for n ≤ 80, the chains are clearly ≥ 1, which leads to the conclusion that the liquid n-alkanes are far away from the Rouse regime, but for the n-alkanes for n ≥ 120, the chains are ⁓ 1 and they are Gaussian. It is found that the long chains of these n-alkanes at high temperatures show abnormalities in density, viscosity, and monomeric friction constant. The mass and temperature dependences of structural and dynamic properties (η, D, and ζ) are discussed

Three-dimensional nanometer scale analyses of precipitate structures and local compositions in titanium aluminide engineering alloys

Science.gov (United States)

Gerstl, Stephan S. A.

Titanium aluminide (TiAl) alloys are among the fastest developing class of materials for use in high temperature structural applications. Their low density and high strength make them excellent candidates for both engine and airframe applications. Creep properties of TiAl alloys, however, have been a limiting factor in applying the material to a larger commercial market. In this research, nanometer scale compositional and structural analyses of several TiAl alloys, ranging from model Ti-Al-C ternary alloys to putative commercial alloys with 10 components are investigated utilizing three dimensional atom probe (3DAP) and transmission electron microscopies. Nanometer sized borides, silicides, and carbide precipitates are involved in strengthening TiAl alloys, however, chemical partitioning measurements reveal oxygen concentrations up to 14 at. % within the precipitate phases, resulting in the realization of oxycarbide formation contributing to the precipitation strengthening of TiAl alloys. The local compositions of lamellar microstructures and a variety of precipitates in the TiAl system, including boride, silicide, binary carbides, and intermetallic carbides are investigated. Chemical partitioning of the microalloying elements between the alpha2/gamma lamellar phases, and the precipitate/gamma-matrix phases are determined. Both W and Hf have been shown to exhibit a near interfacial excess of 0.26 and 0.35 atoms nm-2 respectively within ca. 7 nm of lamellar interfaces in a complex TiAl alloy. In the case of needle-shaped perovskite Ti3AlC carbide precipitates, periodic domain boundaries are observed 5.3+/-0.8 nm apart along their growth axis parallel to the TiAl[001] crystallographic direction with concomitant composition variations after 24 hrs. at 800°C.

Nanometer range closed-loop control of a stepper micro-motor for data storage

NARCIS (Netherlands)

Patrascu, M.; Stramigioli, Stefano; de Boer, Meint J.; Krijnen, Gijsbertus J.M.

2007-01-01

We present a nanometer range, closed-loop control study for MEMS stepper actuators. Although generically applicable to other types of stepper motors, the control design presented here was particularly intended for one dimensional shuffle actuators fabricated by surface micromachining technology. The

Nanostructure Size Determination in N+-Type Porous Silicon by X-Ray diffractometry and Raman Spectroscopy

International Nuclear Information System (INIS)

Ramirez Porras, A.

1997-01-01

A series of porous silicon surfaces were obtained after different exposition times of electrochemical etching on cristalline n+- type silicon in presence of hydrofluoric acid. These kind of surfaces show photoluminescence when illuminated by UV light. One possible explanation for this is that the treated surface is made up of small crystallites the nanometer scale that split away the semiconductor band edges up to optical photon energies for the band- to -band recombination processes. In this study, a nanometer size determination of such proposed structures was performed by the use of X-Ray Diffractometry and Raman Spectroscopy. The result suggest the consistency between the so called Quantum Confined Model and the experimental results. (Author) [es

Nanostructure Size Determination in N+-Type Porous Silicon by X-Ray diffractometry and Raman Spectroscopy

CERN Document Server

Ramirez-Porras, A

1997-01-01

A series of porous silicon surfaces were obtained after different exposition times of electrochemical etching on cristalline n+- type silicon in presence of hydrofluoric acid. These kind of surfaces show photoluminescence when illuminated by UV light. One possible explanation for this is that the treated surface is made up of small crystallites the nanometer scale that split away the semiconductor band edges up to optical photon energies for the band- to -band recombination processes. In this study, a nanometer size determination of such proposed structures was performed by the use of X-Ray Diffractometry and Raman Spectroscopy. The result suggest the consistency between the so called Quantum Confined Model and the experimental results. (Author)

A differential Michelson interferometer with orthogonal single frequency laser for nanometer displacement measurement

International Nuclear Information System (INIS)

Yan, Liping; Chen, Benyong; Wang, Bin

2017-01-01

A novel differential Michelson laser interferometer is proposed to eliminate the influence of environmental fluctuations for nanometer displacement measurement. This differential interferometer consists of two homodyne interferometers in which two orthogonal single frequency beams share common reference arm and partial measurement arm. By modulating the displacement of the common reference arm with a piezoelectric transducer, the common-mode displacement drift resulting from the environmental disturbances can be well suppressed and the measured displacement as differential-mode displacement signal is achieved. In addition, a phase difference compensation method is proposed for accurately determining the phase difference between interference signals by correcting the time interval according to the average speed in one cycle of interference signal. The nanometer displacement measurement experiments were performed to demonstrate the effectiveness and feasibility of the proposed interferometer and show that precision displacement measurement with standard deviation less than 1 nm has been achieved. (paper)

NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

International Nuclear Information System (INIS)

Foerland, Kjersti

2005-01-01

In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41

NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

Energy Technology Data Exchange (ETDEWEB)

Foerland, Kjersti

2005-07-01

In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41.

Micrometer and nanometer-scale parallel patterning of ceramic and organic-inorganic hybrid materials

NARCIS (Netherlands)

ten Elshof, Johan E.; Khan, Sajid; Göbel, Ole

2010-01-01

This review gives an overview of the progress made in recent years in the development of low-cost parallel patterning techniques for ceramic materials, silica, and organic–inorganic silsesquioxane-based hybrids from wet-chemical solutions and suspensions on the micrometer and nanometer-scale. The

Counter current 'emulsion flow' extractor for continuous liquid-liquid extraction from suspended solutions

International Nuclear Information System (INIS)

Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji

2011-01-01

A single current 'emulsion flow' liquid-liquid extraction apparatus has a head with a number of holes from which micrometer-sized droplets of an aqueous phase spout into an organic phase to mix the two liquid phases. For practical use, however, a fatal problem can occur when particulate components in the aqueous phase plug the holes. In the present study, we have succeeded in solving the problem by applying a counter current-type emulsion flow extractor where micrometer-sized droplets of the organic phase are generated. (author)

Imaging and Patterning on Nanometer Scale Using Coherent EUV Light

International Nuclear Information System (INIS)

Wachulak, P.W.; Fiedorowicz, H.; Bartnik, A.; Marconi, M.C.; Menoni, C.S.; Rocca, J.J.

2010-01-01

Extreme ultraviolet (EUV) covers wavelength range from about 5 nm to 50 nm. That is why EUV is especially applicable for imaging and patterning on nanometer scale length. In the paper periodic nanopatterning realized by interference lithography and high resolution holographic nanoimaging performed in a Gabor in-line scheme are presented. In the experiments a compact table top EUV laser was used. Preliminary studies on using a laser plasma EUV source for nanoimaging are presented as well. (author)

Nanolithography and nanochemistry: probe-related patterning techniques and chemical modification for nanometer-sized devices

NARCIS (Netherlands)

Wouters, D.; Schubert, U.S.

2004-01-01

The size regime for devices produced by photolithographic techniques is limited. Therefore, other patterning techniques have been intensively studied to create smaller structures. Scanning-probe-based patterning techniques, such as dip-pen lithography, local force-induced patterning, and local-probe

Stable water isotopologue ratios in fog and cloud droplets of liquid clouds are not size-dependent

Science.gov (United States)

Spiegel, J.K.; Aemisegger, F.; Scholl, M.; Wienhold, F.G.; Collett, J.L.; Lee, T.; van Pinxteren, D.; Mertes, S.; Tilgner, A.; Herrmann, H.; Werner, Roland A.; Buchmann, N.; Eugster, W.

2012-01-01

In this work, we present the first observations of stable water isotopologue ratios in cloud droplets of different sizes collected simultaneously. We address the question whether the isotope ratio of droplets in a liquid cloud varies as a function of droplet size. Samples were collected from a ground intercepted cloud (= fog) during the Hill Cap Cloud Thuringia 2010 campaign (HCCT-2010) using a three-stage Caltech Active Strand Cloud water Collector (CASCC). An instrument test revealed that no artificial isotopic fractionation occurs during sample collection with the CASCC. Furthermore, we could experimentally confirm the hypothesis that the δ values of cloud droplets of the relevant droplet sizes (μm-range) were not significantly different and thus can be assumed to be in isotopic equilibrium immediately with the surrounding water vapor. However, during the dissolution period of the cloud, when the supersaturation inside the cloud decreased and the cloud began to clear, differences in isotope ratios of the different droplet sizes tended to be larger. This is likely to result from the cloud's heterogeneity, implying that larger and smaller cloud droplets have been collected at different moments in time, delivering isotope ratios from different collection times.

Stable water isotopologue ratios in fog and cloud droplets of liquid clouds are not size-dependent

Directory of Open Access Journals (Sweden)

J. K. Spiegel

2012-10-01

Full Text Available In this work, we present the first observations of stable water isotopologue ratios in cloud droplets of different sizes collected simultaneously. We address the question whether the isotope ratio of droplets in a liquid cloud varies as a function of droplet size. Samples were collected from a ground intercepted cloud (= fog during the Hill Cap Cloud Thuringia 2010 campaign (HCCT-2010 using a three-stage Caltech Active Strand Cloud water Collector (CASCC. An instrument test revealed that no artificial isotopic fractionation occurs during sample collection with the CASCC. Furthermore, we could experimentally confirm the hypothesis that the δ values of cloud droplets of the relevant droplet sizes (μm-range were not significantly different and thus can be assumed to be in isotopic equilibrium immediately with the surrounding water vapor. However, during the dissolution period of the cloud, when the supersaturation inside the cloud decreased and the cloud began to clear, differences in isotope ratios of the different droplet sizes tended to be larger. This is likely to result from the cloud's heterogeneity, implying that larger and smaller cloud droplets have been collected at different moments in time, delivering isotope ratios from different collection times.

Simultaneous electropolishing and electrodeposition of aluminum in ionic liquid under ambient conditions

Science.gov (United States)

Hou, Yuanyuan; Li, Ruiqian; Liang, Jun

2018-03-01

Electrodeposition and electropolishing of aluminum are achieved simultaneously in the ionic liquid composed of anhydrous aluminum chloride and trimethylamine hydrochloride. With the protection of a hydrocarbon layer, the process can be carried out under ambient atmosphere. As a result, a smooth mirror-like surface with the roughness only several nanometers is obtained on the anode Al and a uniform Al coating with the thickness about 5 μm is covered on the cathode. Importantly, this work presents the recycling of Al resource in a closed system.

Nanometer-scale sizing accuracy of particle suspensions on an unmodified cell phone using elastic light scattering.

Science.gov (United States)

Smith, Zachary J; Chu, Kaiqin; Wachsmann-Hogiu, Sebastian

2012-01-01

We report on the construction of a Fourier plane imaging system attached to a cell phone. By illuminating particle suspensions with a collimated beam from an inexpensive diode laser, angularly resolved scattering patterns are imaged by the phone's camera. Analyzing these patterns with Mie theory results in predictions of size distributions of the particles in suspension. Despite using consumer grade electronics, we extracted size distributions of sphere suspensions with better than 20 nm accuracy in determining the mean size. We also show results from milk, yeast, and blood cells. Performing these measurements on a portable device presents opportunities for field-testing of food quality, process monitoring, and medical diagnosis.

Nanometer-scale temperature imaging for independent observation of Joule and Peltier effects in phase change memory devices.

Science.gov (United States)

Grosse, Kyle L; Pop, Eric; King, William P

2014-09-01

This paper reports a technique for independent observation of nanometer-scale Joule heating and thermoelectric effects, using atomic force microscopy (AFM) based measurements of nanometer-scale temperature fields. When electrical current flows through nanoscale devices and contacts the temperature distribution is governed by both Joule and thermoelectric effects. When the device is driven by an electrical current that is both periodic and bipolar, the temperature rise due to the Joule effect is at a different harmonic than the temperature rise due to the Peltier effect. An AFM tip scanning over the device can simultaneously measure all of the relevant harmonic responses, such that the Joule effect and the Peltier effect can be independently measured. Here we demonstrate the efficacy of the technique by measuring Joule and Peltier effects in phase change memory devices. By comparing the observed temperature responses of these working devices, we measure the device thermopower, which is in the range of 30 ± 3 to 250 ± 10 μV K(-1). This technique could facilitate improved measurements of thermoelectric phenomena and properties at the nanometer-scale.

Nanometer-scale temperature imaging for independent observation of Joule and Peltier effects in phase change memory devices

Energy Technology Data Exchange (ETDEWEB)

Grosse, Kyle L. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Pop, Eric [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); King, William P., E-mail: wpk@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2014-09-15

This paper reports a technique for independent observation of nanometer-scale Joule heating and thermoelectric effects, using atomic force microscopy (AFM) based measurements of nanometer-scale temperature fields. When electrical current flows through nanoscale devices and contacts the temperature distribution is governed by both Joule and thermoelectric effects. When the device is driven by an electrical current that is both periodic and bipolar, the temperature rise due to the Joule effect is at a different harmonic than the temperature rise due to the Peltier effect. An AFM tip scanning over the device can simultaneously measure all of the relevant harmonic responses, such that the Joule effect and the Peltier effect can be independently measured. Here we demonstrate the efficacy of the technique by measuring Joule and Peltier effects in phase change memory devices. By comparing the observed temperature responses of these working devices, we measure the device thermopower, which is in the range of 30 ± 3 to 250 ± 10 μV K{sup −1}. This technique could facilitate improved measurements of thermoelectric phenomena and properties at the nanometer-scale.

Interdiffusion in nanometer-scale multilayers investigated by in situ low-angle x-ray diffraction

Science.gov (United States)

Wang, Wei-Hua; Bai, Hai Yang; Zhang, Ming; Zhao, J. H.; Zhang, X. Y.; Wang, W. K.

1999-04-01

An in situ low-angle x-ray diffraction technique is used to investigate interdiffusion phenomena in various metal-metal and metal-amorphous Si nanometer-scale compositionally modulated multilayers (ML's). The temperature-dependent interdiffusivities are obtained by accurately monitoring the decay of the first-order modulation peak as a function of annealing time. Activation enthalpies and preexponential factors for the interdiffusion in the Fe-Ti, Ag-Bi, Fe-Mo, Mo-Si, Ni-Si, Nb-Si, and Ag-Si ML's are determined. Activation enthalpies and preexponential factors for the interdiffusion in the ML's are very small compared with that in amorphous alloys and crystalline solids. The relation between the atomic-size difference and interdiffusion in the ML's are investigated. The observed interdiffusion characteristics are compared with that in amorphous alloys and crystalline α-Zr, α-Ti, and Si. The experimental results suggest that a collective atomic-jumping mechanism govern the interdiffusion in the ML's, the collective proposal involving 8-15 atoms moving between extended nonequilibrium defects by thermal activation. The role of the interdiffusion in the solid-state reaction in the ML's is also discussed.

DISSOLVED ORGANIC-MATTER, CADMIUM, COPPER AND ZINC IN PIG SLURRY-SIZE AND SOIL SOLUTION-SIZE EXCLUSION CHROMATOGRAPHY FRACTIONS

NARCIS (Netherlands)

DELCASTILHO, P; DALENBERG, JW; BRUNT, K; BRUINS, AP

1993-01-01

Sephadex size exclusion chromatography was used to prepare molecular size fractions from liquid pig slurry, before and after aerobic interaction with a loamy-sand soil. In the liquid fractions organic matter was characterized and some components were identified. The distribution of zinc and copper

Nanoparticle heterodimers: The role of size and interparticle gap distance on the optical response

Science.gov (United States)

Mokkath, Junais Habeeb

2018-05-01

Composite plasmonic nanostructures with controlled size, shape and relative arrangement is a subject of significant current research interest. Much of this is stimulated by the prospects by generating enormous near-field enhancements of the surface and interparticle gap regions for potential applications in surface-enhanced spectroscopies. In this manuscript, using time-dependent density functional theory (TDDFT) calculations, we investigate how the optical response in size matched homodimers and size mismatched heterodimers composed of Aluminum modify while varying the size and interparticle gap distances in the sub-nanometer range. Both systems show interesting optical response evolution. In particular, the size mismatched heterodimers show even more complex optical response evolution due to a symmetry-breaking in the system.

Nanometer-scale displacement measurement with high resolution using dual cavity Fabry-Pérot interferometer for biomimetic robots.

Science.gov (United States)

Lee, Jin-Hyuk; Kim, Dae-Hyun

2014-10-01

A sensor of a biomimetic robot has to measure very small environmental changes such as, nanometer scale strains or displacements. Fiber optic sensor can be also one of candidates for the biomimetic sensor because the sensor is like thread and the shape of the sensor is similar to muscle fiber. A fiber optic interferometer, which is an optical-based sensor, can measure displacement precisely, so such device has been widely studied for the measurement of displacement on a nanometer-scale. Especially, a Quadrature Phase-Shifted Fiber Fabry-Pérot interferometer (QPS-FFPI) uses phase-information for this measurement, allowing it to provide a precision result with high resolution. In theory, the QPS-FFPI generates two sinusoidal signals of which the phase difference should be 90 degrees for the exact measurement of the displacement. In order to guarantee the condition of the phase difference, the relative adjustment of the cavities of the optical fibers is required. However, with such precise adjustment it is very hard to fix the proper difference of the two cavities for quadrature-phase-shifting. In this paper, a dual-cavity FFPI is newly proposed to measure the displacement on a nanometer-scale with a specific type of signal processing. In the signal processing, a novel phase-compensation algorithm is applied to force the phase difference to be exactly 90 degrees without any physical adjustment. As a result, the paper shows that the phase-compensated dual-cavity FFPI can effectively measure nanometer-scale displacement with high resolution under dynamic conditions.

Mapping Thermal Expansion Coefficients in Freestanding 2D Materials at the Nanometer Scale

Science.gov (United States)

Hu, Xuan; Yasaei, Poya; Jokisaari, Jacob; Öǧüt, Serdar; Salehi-Khojin, Amin; Klie, Robert F.

2018-02-01

Two-dimensional materials, including graphene, transition metal dichalcogenides and their heterostructures, exhibit great potential for a variety of applications, such as transistors, spintronics, and photovoltaics. While the miniaturization offers remarkable improvements in electrical performance, heat dissipation and thermal mismatch can be a problem in designing electronic devices based on two-dimensional materials. Quantifying the thermal expansion coefficient of 2D materials requires temperature measurements at nanometer scale. Here, we introduce a novel nanometer-scale thermometry approach to measure temperature and quantify the thermal expansion coefficients in 2D materials based on scanning transmission electron microscopy combined with electron energy-loss spectroscopy to determine the energy shift of the plasmon resonance peak of 2D materials as a function of sample temperature. By combining these measurements with first-principles modeling, the thermal expansion coefficients (TECs) of single-layer and freestanding graphene and bulk, as well as monolayer MoS2 , MoSe2 , WS2 , or WSe2 , are directly determined and mapped.

Nanometer-scale sizing accuracy of particle suspensions on an unmodified cell phone using elastic light scattering.

Directory of Open Access Journals (Sweden)

Zachary J Smith

Full Text Available We report on the construction of a Fourier plane imaging system attached to a cell phone. By illuminating particle suspensions with a collimated beam from an inexpensive diode laser, angularly resolved scattering patterns are imaged by the phone's camera. Analyzing these patterns with Mie theory results in predictions of size distributions of the particles in suspension. Despite using consumer grade electronics, we extracted size distributions of sphere suspensions with better than 20 nm accuracy in determining the mean size. We also show results from milk, yeast, and blood cells. Performing these measurements on a portable device presents opportunities for field-testing of food quality, process monitoring, and medical diagnosis.

Mean droplet size and local velocity in horizontal isothermal free jets of air and water, respectively, viscous liquid in quiescent ambient air

Energy Technology Data Exchange (ETDEWEB)

Al Rabadi, S.; Friedel, L. [Fluid Mechanics Institute, Technical University of Hamburg-Harburg (Germany); Al Salaymeh, A. [Mechanical Engineering Department, University of Jordan (Jordan)

2007-01-15

Measurements using two-dimensional Phase Doppler Anemometry as well as high speed cinematography in free jets at several nozzle exit pressures and mass flow rates, show that the Sauter mean droplet diameter decreases with increasing air and liquid-phase mass flow ratio due to the increase of the air stream impact on the liquid phase. This leads to substantial liquid fragmentation, respectively primary droplet breakup, and hence, satellite droplet formation with small sizes. This trend is also significant in the case of a liquid viscosity higher than that of water. The increased liquid viscosity stabilizes the droplet formation and breakup by reducing the rate of surface perturbations and consequently droplet distortions, ultimately also leading, in total, to the formation of smaller droplets. The droplet velocity decreases with the nozzle downstream distance, basically due to the continual air entrainment and due to the collisions between the droplets. The droplet collisions may induce further liquid fragmentation and, hence, formation of a number of relatively smaller droplets respectively secondary breakup, or may induce agglomeration to comparatively larger liquid fragments that may rain out of the free jet. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Vapor-liquid-solid mechanisms: Challenges for nanosized quantum cluster/dot/wire materials

Science.gov (United States)

Cheyssac, P.; Sacilotti, M.; Patriarche, G.

2006-08-01

The growth mechanism model of a nanoscaled material is a critical step that has to be refined for a better understanding of a nanostructure's dot/wire fabrication. To do so, the growth mechanism will be discussed in this paper and the influence of the size of the metallic nanocluster starting point, referred to later as "size effect," will be studied. Among many of the so-called size effects, a tremendous decrease of the melting point of the metallic nanocluster changes the physical properties as well as the physical/mechanical interactions inside the growing structure composed of a metallic dot on top of a column. The thermodynamic size effect is related to the bending or curvature of chains of atoms, giving rise to the weakening of bonds between them; this size or curvature effect is described and approached to crystal nanodot/wire growth. We will describe this effect as that of a "cooking machine" when the number of atoms decreases from ˜1023at./cm3 for a bulk material to a few tens of them in a 1-2nm diameter sphere. The decrease of the number of atoms in a metallic cluster from such an enormous quantity is accompanied by a lowering of the melting temperature that extends from 200 up to 1000K, depending on the metallic material and its size under study. In this respect, the vapor-liquid-solid (VLS) model, which is the most utilized growth mechanism for quantum nanowires and nanodots, is critically exposed to size or curvature effects (CEs). More precisely, interactions in the vicinity of the growth regions should be reexamined. Some results illustrating the growth of micrometer-/nanometer-sized materials are presented in order to corroborate the CE/VLS models utilized by many research groups in today's nanosciences world. Examples of metallic clusters and semiconducting wires will be presented. The results and comments presented in this paper can be seen as a challenge to be overcome. From them, we expect that in a near future an improved model can be exposed

Fabrication of thin TEM sample of ionic liquid for high-resolution ELNES measurements

Energy Technology Data Exchange (ETDEWEB)

Miyata, Tomohiro, E-mail: tomo-m@iis.u-tokyo.ac.jp; Mizoguchi, Teruyasu, E-mail: teru@iis.u-tokyo.ac.jp

2017-07-15

Investigation of the local structure, ionic and molecular behavior, and chemical reactions at high spatial resolutions in liquids has become increasingly important. Improvements in these areas help to develop efficient batteries and improve organic syntheses. Transmission electron microscopy (TEM) and scanning-TEM (STEM) have excellent spatial resolution, and the electron energy-loss near edge structure (ELNES) measured by the accompanied electron energy-loss spectroscopy (EELS) is effective to analyze the liquid local structure owing to reflecting the electronic density of states. In this study, we fabricate a liquid-layer-only sample with thickness of single to tens nanometers using an ionic liquid. Because the liquid film has a thickness much less than the inelastic mean free path (IMFP) of the electron beam, the fine structure of the C-K edge electron energy loss near edge structure (ELNES) can be measured with sufficient resolution to allow meaningful analysis. The ELNES spectrum from the thin liquid film has been interpreted using first principles ELNES calculations. - Highlights: • A fabrication method of thin liquid film samples for STEM-EELS observations is proposed. • The thickness of the fabricated thin liquid film is about 10 nm. • An ELNES is measured from the thin liquid with a high energy resolution. • The peaks of the ELNES are interpreted using first principles calculations.

Deposition of Nanostructured Thin Film from Size-Classified Nanoparticles

Science.gov (United States)

Camata, Renato P.; Cunningham, Nicholas C.; Seol, Kwang Soo; Okada, Yoshiki; Takeuchi, Kazuo

2003-01-01

Materials comprising nanometer-sized grains (approximately 1_50 nm) exhibit properties dramatically different from those of their homogeneous and uniform counterparts. These properties vary with size, shape, and composition of nanoscale grains. Thus, nanoparticles may be used as building blocks to engineer tailor-made artificial materials with desired properties, such as non-linear optical absorption, tunable light emission, charge-storage behavior, selective catalytic activity, and countless other characteristics. This bottom-up engineering approach requires exquisite control over nanoparticle size, shape, and composition. We describe the design and characterization of an aerosol system conceived for the deposition of size classified nanoparticles whose performance is consistent with these strict demands. A nanoparticle aerosol is generated by laser ablation and sorted according to size using a differential mobility analyzer. Nanoparticles within a chosen window of sizes (e.g., (8.0 plus or minus 0.6) nm) are deposited electrostatically on a surface forming a film of the desired material. The system allows the assembly and engineering of thin films using size-classified nanoparticles as building blocks.

Note: Development of a microfabricated sensor to measure thermal conductivity of picoliter scale liquid samples.

Science.gov (United States)

Park, Byoung Kyoo; Yi, Namwoo; Park, Jaesung; Kim, Dongsik

2012-10-01

This paper presents a thermal analysis device, which can measure thermal conductivity of picoliter scale liquid sample. We employ the three omega method with a microfabricated AC thermal sensor with nanometer width heater. The liquid sample is confined by a micro-well structure fabricated on the sensor surface. The performance of the instrument was verified by measuring the thermal conductivity of 27-picoliter samples of de-ionized (DI) water, ethanol, methanol, and DI water-ethanol mixtures with accuracies better than 3%. Furthermore, another analytical scheme allows real-time thermal conductivity measurement with 5% accuracy. To the best of our knowledge, this technique requires the smallest volume of sample to measure thermal property ever.

Diamond cubic phase of monoolein and water as an amphiphilic matrix for electrophoresis of oligonucleotides.

Science.gov (United States)

Carlsson, Nils; Winge, Ann-Sofie; Engström, Sven; Akerman, Björn

2005-10-06

We used a cubic liquid crystal formed by the nonionic monoglyceride monoolein and water as a porous matrix for the electrophoresis of oligonucleotides. The diamond cubic phase is thermodynamically stable when in contact with a water-rich phase, which we exploit to run the electrophoresis in the useful submarine mode. Oligonucleotides are separated according to size and secondary structure by migration through the space-filling aqueous nanometer pores of the regular liquid crystal, but the comparatively slow migration means the cubic phase will not be a replacement for the conventional DNA gels. However, our demonstration that the cubic phase can be used in submarine electrophoresis opens up the possibility for a new matrix for electrophoresis of amphiphilic molecules. From this perspective, the results on the oligonucleotides show that water-soluble particles of nanometer size, typical for the hydrophilic parts of membrane-bound proteins, may be a useful separation motif. A charged contamination in the commercial sample of monoolein, most likely oleic acid that arises from its hydrolysis, restricts useful buffer conditions to a pH below 5.6.

Validity of Dynamic Light Scattering Method to Analyze a Range of Gold and Copper Nanoparticle Sizes Attained by Solids Laser Ablation in Liquid

Directory of Open Access Journals (Sweden)

Yu. V. Golubenko

2014-01-01

Full Text Available Nanoparticles of metals possess a whole series of features, concerned with it’s sizes, this leads to appearing or unusual electromagnetic and optical properties, which are untypical for particulates.An extended method of receiving nanoparticles by means of laser radiation is pulse laser ablation of hard targets in liquid medium.Varying the parameters of laser radiation, such as wavelength of laser radiation, energy density, etc., we can operate the size and shape of the resultant particles.The greatest trend of application in medicine have the nanoparticles of iron, copper, silver, silicon, magnesium, gold and zinc.The subject matter in this work is nanoparticles of copper and gold, received by means of laser ablation of hard targets in liquid medium.The aim of exploration, represented in the article, is the estimation of application of the dynamic light scattering method for determination of the range of nanoparticles sizes in the colloidal solution.For studying of the laser ablation process was chosen the second harmonic of Nd:YAG laser with the wavelength of 532 nm. Special attention was spared for the description of the experiment technique of receiving of nanoparticles.As the liquid medium ethanol and distillation water were used.For exploration of the received colloidal system have been used the next methods: DLS, transmission electron microscopy (TEM and scanning electron microscopy (SEM.The results of measuring by DLS method showed that colloidal solution of the copper in the ethanol is the steady system. Copper nanoparticle’s size reaches 200 nm and is staying in the same size for some time.Received system from the gold’s nanoparticles is polydisperse, unsteady and has a big range of the nanoparticle’s sizes. This fact was confirmed by means of photos, got from the TEM FEI Tecnai G2F20 + GIF and SEM Helios NanoLab 660. The range of the gold nanoparticle’s sizes is from 5 to 60 nm. So, it has been proved that the DLS method is

Coalescence collision of liquid drops I: Off-center collisions of equal-size drops

Directory of Open Access Journals (Sweden)

Alejandro Acevedo-Malavé

2011-09-01

Full Text Available The Smoothed Particle Hydrodynamics method (SPH is used here to model off-center collisions of equal-size liquid drops in a three-dimensional space. In this study the Weber number is calculated for several conditions of the droplets dynamics and the velocity vector fields formed inside the drops during the collision process are shown. For the permanent coalescence the evolution of the kinetic and internal energy is shown and also the approaching to equilibrium of the resulting drop. Depending of the Weber number three possible outcomes for the collision of droplets is obtained: permanent coalescence, flocculation and fragmentation. The fragmentation phenomena are modeled and the formation of small satellite drops can be seen. The ligament that is formed follows the “end pinching” mechanism and it is transformed into a flat structure.

The finite-size effect in thin liquid crystal systems

Science.gov (United States)

Śliwa, I.

2018-05-01

Effects of surface ordering in liquid crystal systems confined between cell plates are of great theoretical and experimental interest. Liquid crystals introduced in thin cells are known to be strongly stabilized and ordered by cell plates. We introduce a new theoretical method for analyzing the effect of surfaces on local molecular ordering in thin liquid crystal systems with planar geometry of the smectic layers. Our results show that, due to the interplay between pair long-range intermolecular forces and nonlocal, relatively short-range, surface interactions, both orientational and translational orders of liquid crystal molecules across confining cells are very complex. In particular, it is demonstrated that the SmA, nematic, and isotropic phases can coexist. The phase transitions from SmA to nematic, as well as from nematic to isotropic phases, occur not simultaneously in the whole volume of the system but begin to appear locally in some regions of the LC sample. Phase transition temperatures are demonstrated to be strongly affected by the thickness of the LC system. The dependence of the corresponding shifts of phase transition temperatures on the layer number is shown to exhibit a power law character. This new type of scaling behavior is concerned with the coexistence of local phases in finite systems. The influence of a specific character of interactions of molecules with surfaces and other molecules on values of the resulting critical exponents is also analyzed.

Nanometer-size magnetic domains and coherent magnetization reversal in a giant exchange-bias system

DEFF Research Database (Denmark)

Dufour, C.; Fitzsimmons, M. R.; Borchers, J. A.

2011-01-01

The role of magnetic domains and domain walls in exchange bias has stimulated much contemporary deliberation. Here we present compelling evidence obtained with small-angle scattering of unpolarized- and polarized-neutron beams that magnetization reversal occurs via formation of 10-100s nm-sized m...... to that of structural defects at the seed-layer-superlattice interface....

Transmission electron microscopical study of teenage crown dentin on the nanometer scale

Energy Technology Data Exchange (ETDEWEB)

Panfilov, Peter, E-mail: peter.panfilov@urfu.ru [Ural Federal University, Ekaterinburg (Russian Federation); Kabanova, Anna [Ural Federal University, Ekaterinburg (Russian Federation); Guo, Jinming; Zhang, Zaoli [Erich Schmid Institute for Materials Science, Austrian Academy of Sciences, Leoben (Austria)

2017-02-01

Statement of significance: This is the first transmission electron microscopic study of teenage crown dentin on the nanometer scale. Samples for TEM were prepared by mechanical thinning and chemical polishing that allowed obtaining the electron transparent foils. It was firstly shown that human dentin possesses the layered morphology: the layers are oriented normally to the main axis of a tooth and have the thickness of ~ 50 nm. HA inorganic phase of teenage crown dentin is in the amorphous state. The cellular structure, which was formed from collagen fibers (diameter is ~ 5 nm), are observed near DEJ region in teenage dentin, whereas bioorganic phase of teenage crown dentin near the pulp camera does not contain the collagen fibers. Cracks in dentin thin foils have sharp tips, but big angles of opening (~ 30{sup °}) with plastic zone ahead crack tip. It means that young crown human dentin exhibits ductile or viscous-elastic fracture behavior on the nanometer scale. - Highlights: • Dentin has layered morphology. • Mineral component of dentin is in amorphous state. • Collagen fibers form cellular structure in dentin. • Cracks in dentin behave by elastic-plastic manner.

Transmission electron microscopical study of teenage crown dentin on the nanometer scale

International Nuclear Information System (INIS)

Panfilov, Peter; Kabanova, Anna; Guo, Jinming; Zhang, Zaoli

2017-01-01

Statement of significance: This is the first transmission electron microscopic study of teenage crown dentin on the nanometer scale. Samples for TEM were prepared by mechanical thinning and chemical polishing that allowed obtaining the electron transparent foils. It was firstly shown that human dentin possesses the layered morphology: the layers are oriented normally to the main axis of a tooth and have the thickness of ~ 50 nm. HA inorganic phase of teenage crown dentin is in the amorphous state. The cellular structure, which was formed from collagen fibers (diameter is ~ 5 nm), are observed near DEJ region in teenage dentin, whereas bioorganic phase of teenage crown dentin near the pulp camera does not contain the collagen fibers. Cracks in dentin thin foils have sharp tips, but big angles of opening (~ 30 ° ) with plastic zone ahead crack tip. It means that young crown human dentin exhibits ductile or viscous-elastic fracture behavior on the nanometer scale. - Highlights: • Dentin has layered morphology. • Mineral component of dentin is in amorphous state. • Collagen fibers form cellular structure in dentin. • Cracks in dentin behave by elastic-plastic manner.

Surface structure evolution in a homologous series of ionic liquids.

Science.gov (United States)

Haddad, Julia; Pontoni, Diego; Murphy, Bridget M; Festersen, Sven; Runge, Benjamin; Magnussen, Olaf M; Steinrück, Hans-Georg; Reichert, Harald; Ocko, Benjamin M; Deutsch, Moshe

2018-02-06

Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation's alkyl chain length [Formula: see text] from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present here such a study of the liquid-air interface for [Formula: see text], using angstrom-resolution X-ray methods. For [Formula: see text], a typical "simple liquid" monotonic surface-normal electron density profile [Formula: see text] is obtained, like those of water and organic solvents. For [Formula: see text], increasingly more pronounced nanoscale self-segregation of the molecules' charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear [Formula: see text] dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For [Formula: see text], a different surface phase is observed above melting. Our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk-surface structure relations.

Hybrid approaches to nanometer-scale patterning: Exploiting tailored intermolecular interactions

International Nuclear Information System (INIS)

Mullen, Thomas J.; Srinivasan, Charan; Shuster, Mitchell J.; Horn, Mark W.; Andrews, Anne M.; Weiss, Paul S.

2008-01-01

In this perspective, we explore hybrid approaches to nanometer-scale patterning, where the precision of molecular self-assembly is combined with the sophistication and fidelity of lithography. Two areas - improving existing lithographic techniques through self-assembly and fabricating chemically patterned surfaces - will be discussed in terms of their advantages, limitations, applications, and future outlook. The creation of such chemical patterns enables new capabilities, including the assembly of biospecific surfaces to be recognized by, and to capture analytes from, complex mixtures. Finally, we speculate on the potential impact and upcoming challenges of these hybrid strategies.

Electron transport in nanometer GaAs structure under radiation exposure

CERN Document Server

Demarina, N V

2002-01-01

One investigates into effect of neutron and proton irradiation on electron transport in nanometer GaAs structures. Mathematical model takes account of radiation defects via introduction of additional mechanisms od scattering of carriers at point defects and disordered regions. To investigate experimentally into volt-ampere and volt-farad characteristics one used a structure based on a field-effect transistor with the Schottky gate and a built-in channel. Calculation results of electron mobility, drift rate of electrons, time of energy relaxation and electron pulse are compared with the experimental data

Frontier of nanometer devices. Part 6. New devices with fully controlled electrons and photons. Nanometa debaisu kenkyu saizensen. 6. Denshi to koshi no kanzen seigyo wo mezashita jisedai debaisu

Energy Technology Data Exchange (ETDEWEB)

Arakawa, Y [The Univ. of Tokyo, Tokyo (Japan). Inst. of Industrial Science

1994-06-20

In the nanotechnology to realize an artificial structure of a magnitude of atomic size, new electron devices and photon devices are aimed by confining electron and controlling the behavior of the electron with transition of a quantum mechanical state including a tunneling effect. The degree of freedom of electron decreased when electron is confined in a very small area within semiconductor and is 1 in a quantum wire while it is 0 in a quantum box. Energy level of electron is completely dispersed. The condition required to realize the nanometer structure is examined and the formation techniques of semiconductor nanometer structure are studied. This paper describes research results by the authors aiming to realize quantum wire and quantum box structures. Ultrafine pattern of SiO2 is formed by electron beam drawing technique followed by crystal growth with a MOCVD method to form the quantum wire and quantum box structures successfully. Laser oscillation is successful at 77K with optical pumping using a quantum wire and vertical micro resonator. 5 refs., 7 figs.

Relation between the ion size and pore size for an electric double-layer capacitor.

Science.gov (United States)

Largeot, Celine; Portet, Cristelle; Chmiola, John; Taberna, Pierre-Louis; Gogotsi, Yury; Simon, Patrice

2008-03-05

The research on electrochemical double layer capacitors (EDLC), also known as supercapacitors or ultracapacitors, is quickly expanding because their power delivery performance fills the gap between dielectric capacitors and traditional batteries. However, many fundamental questions, such as the relations between the pore size of carbon electrodes, ion size of the electrolyte, and the capacitance have not yet been fully answered. We show that the pore size leading to the maximum double-layer capacitance of a TiC-derived carbon electrode in a solvent-free ethyl-methylimmidazolium-bis(trifluoro-methane-sulfonyl)imide (EMI-TFSI) ionic liquid is roughly equal to the ion size (approximately 0.7 nm). The capacitance values of TiC-CDC produced at 500 degrees C are more than 160 F/g and 85 F/cm(3) at 60 degrees C, while standard activated carbons with larger pores and a broader pore size distribution present capacitance values lower than 100 F/g and 50 F/cm(3) in ionic liquids. A significant drop in capacitance has been observed in pores that were larger or smaller than the ion size by just an angstrom, suggesting that the pore size must be tuned with sub-angstrom accuracy when selecting a carbon/ion couple. This work suggests a general approach to EDLC design leading to the maximum energy density, which has been now proved for both solvated organic salts and solvent-free liquid electrolytes.

Droplet size in a rectangular Venturi scrubber

Directory of Open Access Journals (Sweden)

M. A. M. Costa

2004-06-01

Full Text Available The Venturi scrubber is a device which uses liquid in the form of droplets to efficiently remove fine particulate matter from gaseous streams. Droplet size is of fundamental importance for the scrubber performance. In the present experimental study, a laser diffraction technique was used in order to measure droplet size in situ in a Venturi scrubber with a rectangular cross section. Droplet size distribution was measured as a function of gas velocity (58.3 to 74.9 m/s, liquid-to-gas ratio (0.07 to 0.27 l/m³, and distance from liquid injection point (64 to 173 mm. It was found that all these variables significantly affect droplet size. The results were compared with the predictions from correlations found in the literature.

Thermal Stress Behavior of Micro- and Nano-Size Aluminum Films

International Nuclear Information System (INIS)

Hanabusa, T.; Kusaka, K.; Nishida, M.

2008-01-01

In-situ observation of thermal stresses in thin films deposited on silicon substrate was made by X-ray and synchrotron radiation. Specimens prepared in this experiment were micro- and nano-size thin aluminum films with and without passivation film. The thickness of the film was 1 micrometer for micro-size films and 10, 20 and 50 nanometer for nano-size films. The stress measurement in micro-size films was made by X-ray radiation whereas the measurement of nano-size films was made by synchrotron radiation. Residual stress measurement revealed tensile stresses in all as-deposited films. Thermal stresses were measured in a series of heating- and cooling-stage. Thermal stress behavior of micro-size films revealed hysteresis loop during a heating and cooling process. The width of a hysteresis loop was larger in passivated film that unpassivated film. No hysteresis loops were observed in nano-size films with SiO 2 passivation. Strengthning mechanism in thin films was discussed on a passivation film and a film thickness

Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

Science.gov (United States)

A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

Finite size effects in liquid-gas phase transition of asymmetric nuclear matter

International Nuclear Information System (INIS)

Pawlowski, P.

2001-01-01

Full text: Since the nuclear equation of state has been studied in astrophysical context as an element of neutron star or super-nova theories - a call for an evidence was produced in experimental nuclear physics. Heavy-ion collisions became a tool of study on thermodynamic properties of nuclear matter. A particular interest has been inspired here by critical behavior of nuclear systems, as a phase transition of liquid-gas type. A lot of efforts was put to obtain an experimental evidence of such a phenomenon in heavy-ion collisions. With the use of radioactive beams and high performance identification systems in a near future it will be possible to extend experimental investigation to asymmetric nuclear systems, where neutron-to-proton ratio is far from the stability line. This experimental development needs a corresponding extension of theoretical studies. To obtain a complete theory of the liquid-gas phase transition in small nuclear systems, produced in violent heavy-ion collisions, one should take into account two facts. First, that the nuclear matter forming nuclei is composed of protons and neutrons; this complicates the formalism of phase transitions because one has to deal with two separate, proton and neutron, densities and chemical potentials. The second and more important is that the surface effects are very strong in a system composed of a few hundreds of nucleons. This point is especially difficult to hold, because surface becomes an additional, independent state parameter, depending strongly on the geometrical configuration of the system, and introducing a non-local term in the equation of state. In this presentation we follow the recent calculation by Lee and Mekjian on the finite-size effects in small (A = 10 2 -10 3 ) asymmetric nuclear systems. A zero-range isospin-dependent Skyrme force is used to obtain a density and isospin dependent potential. The potential is then completed by additional terms giving contributions from surface and Coulomb

Method and apparatus for sizing nuclear fuel rod cladding tubes

International Nuclear Information System (INIS)

Koehler, L.

1976-01-01

Nuclear fuel rod cladding tubes are sized internally to diameters precisely fitting nuclear fuel pellets with which the tubes are charged by externally applying hydraulic pressure to short lengths of each tube. The pressure is applied while the tube is stationary. The tube is then moved to bring a new length within the hydraulic pressure zone. The volume of the hydraulic liquid used and the pressure applied to this liquid is such that the liquid is compressed slightly so that the length being sized yields, the expansion of the liquid then completing the sizing. The lengths being sized step-by-step are internally supported by either the fuel pellets or a mandrel having the same diameter as the pellets

Photocatalytic performances of BiFeO3 particles with the average size in nanometer, submicrometer, and micrometer

International Nuclear Information System (INIS)

Hao, Chunxue; FushengWen,; Xiang, Jianyong; Hou, Hang; Lv, Weiming; Lv, Yifei; Hu, Wentao; Liu, Zhongyuan

2014-01-01

Highlights: • Three different synthesis routes have been taken to successfully prepare the BiFeO 3 particles with the different morphologies and average size in 50, 500 nm, and 15 μm. • For photodegradation of dyes under visible irradiation in the presence of BiFeO 3 , the photocatalytic efficiency increases quickly with the decrease in size. • The enhanced photocatalytic efficiency of BiFeO 3 nanoparticles may attribute to more surface active catalytic-sites and shorter distances carriers have to migrate to the surface reaction sites. - Abstract: Three different synthesis routes were taken to successfully prepare the BiFeO 3 particles with the different morphologies and average size in 50, 500 nm, and 15 μm, respectively. The crystal structure was recognized to be a distorted rhombohedral one with the space group R3c. With the decrease in particle size, obvious decrease in peak intensity and redshift in peak position were observed for the Raman active bands. The narrow band gap was determined from the UV–vis absorption spectra, indicating the semiconducting nature of the BiFeO 3 . For photodegradation of dyes under visible irradiation in the presence of BiFeO 3 , the photocatalytic efficiency increased quickly with the decrease in size which may attribute to more surface active catalytic-sites and shorter distances carriers had to migrate to the surface reaction sites

Spontaneous Marangoni Mixing of Miscible Liquids at a Liquid-Liquid-Air Contact Line.

Science.gov (United States)

Kim, Hyoungsoo; Lee, Jeongsu; Kim, Tae-Hong; Kim, Ho-Young

2015-08-11

We investigate the flow patterns created when a liquid drop contacts a reservoir liquid, which has implications on various physicochemical and biochemical reactions including mixing in microfluidic systems. The localized vortical flow spontaneously triggered by the difference of surface tension between the two liquids is studied, which is thus termed the Marangoni vortex. To quantitatively investigate the strength of vortices, we performed particle image velocimetry (PIV) experiments by varying the surface tension difference, the gap of the flow cell, the density and viscosity of the reservoir liquid, and the size of the drop. A scaling law that balances the interfacial energy of the system with the kinetic energy of the vortical flows allows us to understand the functional dependence of the Marangoni vortex strength on various experimental parameters.

Formation and surface strengthening of nano-meter embedded phases during high energy Ti implanted and annealed steel

International Nuclear Information System (INIS)

Zhang Tonghe; Wu Yuguang; Cui Ping; Wang Ping

1999-12-01

Observation of transmission electron microscope indicated that the phase of FeTi 2 with 3.5-20 nm in diameter is embedded in high energy Ti implanted layer. It's average diameter is 8 nm. The nano-meter phases were embedded among dislocations and grain boundary in Ti implanted steel at 400 degree C. The wear resistance has been improved. The embedded structure can be changed obviously after annealing. The structure has been changed slightly after annealing at annealing temperature raging from 350 to 500 degree C, however, the hardness and wear resistance of implanted layer increased greatly. The maximum of hardness is obtained when the sample was annealed at 500 degree C for 20 min. It can be seen that the strengthening of implanted layer has enhanced by annealing indeed. The grain boundary and dislocations have disappeared; the diameter of nano-meter phases increased from 10 nm to 15 nm after annealing at temperature of 750 degree C and 1000 degree respectively. The average densities of nano-meter phases are 8.8 x 10 10 /cm 2 and 6.5 x 10 10 /cm 2 respectively for both of annealing temperature. The hardness decreased obviously when the annealing temperature is greater than 750 degree C

Theoretical studies of finite size effects and screening effects caused by a STM tip in Luettinger liquids

International Nuclear Information System (INIS)

Guigou, Marine

2009-01-01

This thesis takes place in the field of condensed matter. More precisely, we focus on the finite size effects and the screening effects caused by a STM tip in a quantum wire. For that, we use, first, the Luettinger liquid theory, which allows to describe strongly correlated systems and secondly, the Keldysh formalism, which is necessary to treat the out-of-equilibrium systems. For these studies, we consider, the currant, the noise and the conductance. The noise presents a non-Poissonian behaviour, when finite size effects appear. Through the photo-assisted transport, it is shown that those effects hide the effects of the Coulomb interactions. Considering the proximity between the STM tip, used as a probe or as an injector, and a quantum wire, screening effects appear. We can conclude that they play a similar role to those of Coulomb interactions. (author) [fr

Liquidity Determinants of Moroccan Banking Industry

OpenAIRE

FERROUHI, El Mehdi; LEHADIRI, Abderrassoul

2013-01-01

This paper analyzes the behavior of Moroccan bank’s liquidity during the period 2001 – 2012. The research aims to identify the determinants of Moroccan bank’s liquidity. We first evaluate Moroccan banks’ liquidity positions through different liquidity ratios to determine the effects of financial crisis on bank’s liquidity. We then highlight the effect of banks’ size on banks’ liquidity. Finally, we identify determinants of Moroccan bank’s liquidity using panel data regression. ...

Non-exponential resistive switching in Ag2S memristors: a key to nanometer-scale non-volatile memory devices.

Science.gov (United States)

Gubicza, Agnes; Csontos, Miklós; Halbritter, András; Mihály, György

2015-03-14

The dynamics of resistive switchings in nanometer-scale metallic junctions formed between an inert metallic tip and an Ag film covered by a thin Ag2S layer are investigated. Our thorough experimental analysis and numerical simulations revealed that the resistance change upon a switching bias voltage pulse exhibits a strongly non-exponential behaviour yielding markedly different response times at different bias levels. Our results demonstrate the merits of Ag2S nanojunctions as nanometer-scale non-volatile memory cells with stable switching ratios, high endurance as well as fast response to write/erase, and an outstanding stability against read operations at technologically optimal bias and current levels.

Resolving the three-dimensional microstructure of polymer electrolyte fuel cell electrodes using nanometer-scale X-ray computed tomography

Energy Technology Data Exchange (ETDEWEB)

Epting, William K.; Gelb, Jeff; Litster, Shawn

2012-02-08

The electrodes of a polymer electrolyte fuel cell (PEFC) are composite porous layers consisting of carbon and platinum nanoparticles and a polymer electrolyte binder. The proper composition and arrangement of these materials for fast reactant transport and high electrochemical activity is crucial to achieving high performance, long lifetimes, and low costs. Here, the microstructure of a PEFC electrode using nanometer-scale X-ray computed tomography (nano-CT) with a resolution of 50 nm is investigated. The nano-CT instrument obtains this resolution for the low-atomic-number catalyst support and binder using a combination of a Fresnel zone plate objective and Zernike phase contrast imaging. High-resolution, non-destructive imaging of the three-dimensional (3D) microstructures provides important new information on the size and form of the catalyst particle agglomerates and pore spaces. Transmission electron microscopy (TEM) and mercury intrusion porosimetry (MIP) is applied to evaluate the limits of the resolution and to verify the 3D reconstructions. The computational reconstructions and size distributions obtained with nano-CT can be used for evaluating electrode preparation, performing pore-scale simulations, and extracting effective morphological parameters for large-scale computational models. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Generating Sub-nanometer Displacement Using Reduction Mechanism Consisting of Torsional Leaf Spring Hinges

Directory of Open Access Journals (Sweden)

Fukuda Makoto

2014-02-01

Full Text Available Recent demand on the measurement resolution of precise positioning comes up to tens of picometers. Some distinguished researches have been performed to measure the displacement in picometer order, however, few of them can verify the measurement performance as available tools in industry. This is not only because the picometer displacement is not yet required for industrial use, but also due to the lack of standard tools to verify such precise displacement. We proposed a displacement reduction mechanism for generating precise displacement using torsional leaf spring hinges (TLSHs that consist of four leaf springs arranged radially. It has been demonstrated that a prototype of the reduction mechanism was able to provide one-nanometer displacement with 1/1000 reduction rate by a piezoelectric actuator. In order to clarify the potential of the reduction mechanism, a displacement reduction table that can be mounted on AFM stage was newly developed using TLSHs. This paper describes the design of the reduction mechanism and the sub-nanometer displacement performance of the table obtained from its dynamic and static characteristics measured by displacement sensors and from the AFM images

Nanopore Measurements of Filamentous Viruses Reveal a Sub-nanometer-Scale Stagnant Fluid Layer.

Science.gov (United States)

McMullen, Angus J; Tang, Jay X; Stein, Derek

2017-11-28

We report measurements and analyses of nanopore translocations by fd and M13, two related strains of filamentous virus that are identical except for their charge densities. The standard continuum theory of electrokinetics greatly overestimates the translocation speed and the conductance associated with counterions for both viruses. Furthermore, fd and M13 behave differently from one another, even translocating in opposite directions under certain conditions. This cannot be explained by Manning-condensed counterions or a number of other proposed models. Instead, we argue that these anomalous findings are consequences of the breakdown of the validity of continuum hydrodynamics at the scale of a few molecular layers. Next to a polyelectrolyte, there exists an extra-viscous, sub-nanometer-thin boundary layer that has a giant influence on the transport characteristics. We show that a stagnant boundary layer captures the essential hydrodynamics and extends the validity of the electrokinetic theory beyond the continuum limit. A stagnant layer with a thickness of about half a nanometer consistently improves predictions of the ionic current change induced by virus translocations and of the translocation velocity for both fd and M13 over a wide range of nanopore dimensions and salt concentrations.

Droplet size in a rectangular Venturi scrubber

OpenAIRE

Costa, M. A. M.; Henrique, P. R.; Gonçalves, J. A. S.; Coury, J.R.

2004-01-01

The Venturi scrubber is a device which uses liquid in the form of droplets to efficiently remove fine particulate matter from gaseous streams. Droplet size is of fundamental importance for the scrubber performance. In the present experimental study, a laser diffraction technique was used in order to measure droplet size in situ in a Venturi scrubber with a rectangular cross section. Droplet size distribution was measured as a function of gas velocity (58.3 to 74.9 m/s), liquid-to-gas ratio (0...

Liquid Chromatography in 1982.

Science.gov (United States)

Freeman, David H.

1982-01-01

Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

"Size-Independent" Single-Electron Tunneling.

Science.gov (United States)

Zhao, Jianli; Sun, Shasha; Swartz, Logan; Riechers, Shawn; Hu, Peiguang; Chen, Shaowei; Zheng, Jie; Liu, Gang-Yu

2015-12-17

Incorporating single-electron tunneling (SET) of metallic nanoparticles (NPs) into modern electronic devices offers great promise to enable new properties; however, it is technically very challenging due to the necessity to integrate ultrasmall (<10 nm) particles into the devices. The nanosize requirements are intrinsic for NPs to exhibit quantum or SET behaviors, for example, 10 nm or smaller, at room temperature. This work represents the first observation of SET that defies the well-known size restriction. Using polycrystalline Au NPs synthesized via our newly developed solid-state glycine matrices method, a Coulomb Blockade was observed for particles as large as tens of nanometers, and the blockade voltage exhibited little dependence on the size of the NPs. These observations are counterintuitive at first glance. Further investigations reveal that each observed SET arises from the ultrasmall single crystalline grain(s) within the polycrystal NP, which is (are) sufficiently isolated from the nearest neighbor grains. This work demonstrates the concept and feasibility to overcome orthodox spatial confinement requirements to achieve quantum effects.

Vapor-liquid phase behavior of a size-asymmetric model of ionic fluids confined in a disordered matrix: The collective-variables-based approach

Science.gov (United States)

Patsahan, O. V.; Patsahan, T. M.; Holovko, M. F.

2018-02-01

We develop a theory based on the method of collective variables to study the vapor-liquid equilibrium of asymmetric ionic fluids confined in a disordered porous matrix. The approach allows us to formulate the perturbation theory using an extension of the scaled particle theory for a description of a reference system presented as a two-component hard-sphere fluid confined in a hard-sphere matrix. Treating an ionic fluid as a size- and charge-asymmetric primitive model (PM) we derive an explicit expression for the relevant chemical potential of a confined ionic system which takes into account the third-order correlations between ions. Using this expression, the phase diagrams for a size-asymmetric PM are calculated for different matrix porosities as well as for different sizes of matrix and fluid particles. It is observed that general trends of the coexistence curves with the matrix porosity are similar to those of simple fluids under disordered confinement, i.e., the coexistence region gets narrower with a decrease of porosity and, simultaneously, the reduced critical temperature Tc* and the critical density ρi,c * become lower. At the same time, our results suggest that an increase in size asymmetry of oppositely charged ions considerably affects the vapor-liquid diagrams leading to a faster decrease of Tc* and ρi,c * and even to a disappearance of the phase transition, especially for the case of small matrix particles.

Electrotunable lubricity with ionic liquids: the influence of nanoscale roughness.

Science.gov (United States)

David, Alessio; Fajardo, Oscar Y; Kornyshev, Alexei A; Urbakh, Michael; Bresme, Fernando

2017-07-01

The properties of ionic liquids can be modified by applying an external electrostatic potential, providing a route to control their performance in nanolubrication applications. Most computational studies to date have focused on the investigation of smooth surfaces. Real surfaces are generally inhomogeneous and feature roughness of different length scales. We report here a study of the possible effects that surface roughness may have on electrotunable lubricity with ionic liquids, performed here by means of non-equilibrium molecular dynamics simulations. In order to advance our understanding of the interplay of friction and substrate structure we investigate coarse grained models of ionic liquids confined in model surfaces with nanometer roughness. The friction is shown to depend on the roughness of the substrate and the direction of shear. For the investigated systems, the friction coefficient is found to increase with roughness. These results are in contrast with previous studies, where roughness induced reduction of friction was reported, and they highlight the strong sensitivity of the friction process to the structure of the surfaces. The friction force features a maximum at a specific surface charge density. This behaviour is reminiscent of the one reported in ionic liquids confined by flat surfaces, showing the generality of this physical effect in confined ionic liquids. We find that an increase of the substrate-liquid dispersion interactions shifts the maximum to lower surface charges. This effect opens a route to control electrotunable friction phenomena by tuning both the electrostatic potential and the composition of the confining surfaces.

Imaging Live Cells at the Nanometer-Scale with Single-Molecule Microscopy: Obstacles and Achievements in Experiment Optimization for Microbiology

Science.gov (United States)

Haas, Beth L.; Matson, Jyl S.; DiRita, Victor J.; Biteen, Julie S.

2015-01-01

Single-molecule fluorescence microscopy enables biological investigations inside living cells to achieve millisecond- and nanometer-scale resolution. Although single-molecule-based methods are becoming increasingly accessible to non-experts, optimizing new single-molecule experiments can be challenging, in particular when super-resolution imaging and tracking are applied to live cells. In this review, we summarize common obstacles to live-cell single-molecule microscopy and describe the methods we have developed and applied to overcome these challenges in live bacteria. We examine the choice of fluorophore and labeling scheme, approaches to achieving single-molecule levels of fluorescence, considerations for maintaining cell viability, and strategies for detecting single-molecule signals in the presence of noise and sample drift. We also discuss methods for analyzing single-molecule trajectories and the challenges presented by the finite size of a bacterial cell and the curvature of the bacterial membrane. PMID:25123183

Temporary core liquid level depression during cold-leg small-break LOCA effect of break size and power level

International Nuclear Information System (INIS)

Koizumi, Y.; Kumamaru, H.; Mimura, Y.; Kukita, Y.; Tasaka, K.

1989-01-01

Cold-leg small break LOCA experiments (0.5-10% break) were conducted at the large scale test facility (LSTF), a volumetrically-scaled (1/48) simulator of a PWR, of the ROSA-IV Program. When a break area was less than 2.5% of the scaled cold-leg flow area, the core liquid level was temporarily further depressed to the bottom elevation of the crossover leg during the loop seal clearing early in the transient only by the manometric pressure balance since no coolant remained in the upper portion of the primary system. When the break size was larger than 5%, the core liquid level was temporarily further depressed lower than the bottom elevation of the crossover leg during the loop seal clearing since coolant remained at the upper portion of the primary system; the steam generator (SG) U-tube upflow side and the SG inlet plenum, due to counter current flow limiting by updrafting steam while the coolant drained. The amount of coolant trapped there was dependent on the vapor velocity (core power); the larger the core power, the lower the minimum core liquid level. The RELAP5/MOD2 code reasonable predicted phenomena observed in the experiments. (orig./DG)

Liquid Marbles

KAUST Repository

Khalil, Kareem

2012-12-01

Granulation, the process of formation of granules from a combination of base powders and binder liquids, has been a subject of research for almost 50 years, studied extensively for its vast applications, primarily to the pharmaceutical industry sector. The principal aim of granulation is to form granules comprised of the active pharmaceutical ingredients (API’s), which have more desirable handling and flowability properties than raw powders. It is also essential to ensure an even distribution of active ingredients within a tablet with the goal of achieving time‐controlled release of drugs. Due to the product‐specific nature of the industry, however, data is largely empirical [1]. For example, the raw powders used can vary in size by two orders of magnitude with narrow or broad size distributions. The physical properties of the binder liquids can also vary significantly depending on the powder properties and required granule size. Some significant progress has been made to better our understanding of the overall granulation process [1] and it is widely accepted that the initial nucleation / wetting stage, when the binder liquid first wets the powders, is key to the whole process. As such, many experimental studies have been conducted in attempt to elucidate the physics of this first stage [1], with two main mechanisms being observed – classified by Ivenson [1] as the “Traditional description” and the “Modern Approach”. See Figure 1 for a graphical definition of these two mechanisms. Recent studies have focused on the latter approach [1] and a new, exciting development in this field is the Liquid Marble. This interesting formation occurs when a liquid droplet interacts with a hydrophobic (or superhydrophobic) powder. The droplet can become encased in the powder, which essentially provides a protective “shell” or “jacket” for the liquid inside [2]. The liquid inside is then isolated from contact with other solids or liquids and has some

A Structural Study of Escherichia coli Cells Using an In Situ Liquid Chamber TEM Technology

Directory of Open Access Journals (Sweden)

Yibing Wang

2015-01-01

Full Text Available Studying cell microstructures and their behaviors under living conditions has been a challenging subject in microbiology. In this work, in situ liquid chamber TEM was used to study structures of Escherichia coli cells in aqueous solutions at a nanometer-scale resolution. Most of the cells remained intact under electron beam irradiation, and nanoscale structures were observed during the TEM imaging. The analysis revealed structures of pili surrounding the E. coli cells; the movements of the pili in the liquid were also observed during the in situ tests. This technology also allowed the observation of features of the nucleoid in the E. coli cells. Overall, in situ TEM can be applied as a valuable tool to study real-time microscopic structures and processes in microbial cells residing in native aqueous solutions.

Development of high strength hot rolled low carbon copper-bearing steel containing nanometer sized carbides

Energy Technology Data Exchange (ETDEWEB)

Phaniraj, M.P. [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Shin, Young-Min [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Lee, Joonho [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Goo, Nam Hoon [Sheet Product Design Group, Hyundai Steel Co., North Industrial Street 1400, 343-823, DangJin 343-823 (Korea, Republic of); Kim, Dong-Ik; Suh, Jin-Yoo; Jung, Woo-Sang [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Shim, Jae-Hyeok, E-mail: jhshim@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Choi, In-Suk, E-mail: insukchoi@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

2015-05-01

A low carbon ferritic steel was alloyed with Ti, Mo and Cu with the intention of achieving greater increment in strength by multiple precipitate strengthening. The steel is hot rolled and subjected to interrupted cooling to enable precipitation of Ti–Mo carbides and copper. Thermodynamic calculations were carried out to determine equilibrium phase fractions at different temperatures. Microstructure characterization using transmission electron microscopy and composition analysis revealed that the steel contains ~5 nm size precipitates of (Ti,Mo)C. Precipitation kinetics calculations using MatCalc software showed that mainly body centered cubic copper precipitates of size < 5nm form under the cooling conditions in the present study. The steel has the high tensile strength of 853 MPa and good ductility. The yield strength increases by 420 MPa, which is more than that achieved in hot rolled low carbon ferritic steels with only copper precipitates or only carbide precipitates. The precipitation and strengthening contribution of copper and (Ti,Mo)C precipitates and their effect on the work hardening behavior is discussed.

Size Effect on Failure of Pre-stretched Free-Standing Nanomembranes

Directory of Open Access Journals (Sweden)

Cheng Wenlong

2010-01-01

Full Text Available Abstract Free-standing nanomembranes are two-dimensional materials with nanometer thickness but can have macroscopic lateral dimensions. We develop a fracture model to evaluate a pre-stretched free standing circular ultrathin nanomembrane and establish a relation between the energy release rate of a circumferential interface crack and the pre-strain in the membrane. Our results demonstrate that detachment cannot occur when the radius of the membrane is smaller than a critical size. This critical radius is inversely proportional to the Young’s modulus and square of the pre-strain of the membrane.

Liquid metal engineering aspects of a commercial-sized power plant based on the hylife converter concept

International Nuclear Information System (INIS)

Hoffman, N.J.; McDowell, M.W.

1979-12-01

A study of a commercial fusion plant based on the High Yield Lithium Injection Fusion Energy (HYLIFE) converter has been performed. A net efficiency of 33.3% was derived for a plant using 2-1/4 Cr - 1 Mo ferritic steel as structural alloy. Use of a thick lithium fall to protect structural materials from the deleterious effects of pellet thermonuclear burn allows the structure to last the life of the plant without replacement. Both mechanical pumps and EM pumps are analyzed for this application. The power requirement for the lithium fall mechanical pumps is approx. 20 MWe. This is a relatively insignificant 1.6% of the gross electrical power output of the plant of approx. 1250 MWe. An EM pump has a greater electrical requirement but the lesser head (NPSH) requirement of an EM pump appears to be a marked advantage since this affects the size of the lithium inventory. The preferred tritium separation method appears to be that developed by Argonne National Laboratory which involves mixing lithium into an immiscible liquid having a greater affinity for hydrogen isotopes, with subsequent electrolytic separation. The immiscible liquid under consideration is a lithium bromide-lithium fluoride-lithium chloride mixture

The nature of the Fe-graphene interface at the nanometer level

International Nuclear Information System (INIS)

Cattelan, Mattia; Artiglia, Luca; Favaro, Marco; Agnoli, Stefano; Granozzi, Gaetano; Peng, Guowen; Roling, Luke T.; Mavrikakis, Manos; Cavaliere, Emanuele; Gavioli, Luca; Barinov, Alexey; Píš, Igor; Nappini, Silvia; Magnano, Elena; Bondino, Federica

2016-01-01

The emerging fields of graphene-based magnetic and spintronic devices require a deep understanding of the interface between graphene and ferromagnetic metals. This work reports a detailed investigation at the nanometer level of the Fe–graphene interface carried out by angle-resolved photoemission, high-resolution photoemission from core levels, and scanning tunnelling microscopy. Quasi-freestanding graphene was grown on Pt(111), and the iron film was either deposited atop or intercalated beneath graphene. Calculations and experimental results show that iron strongly modifies the graphene band structure and lifts its π band spin degeneracy.

The nature of the Fe-graphene interface at the nanometer level

Energy Technology Data Exchange (ETDEWEB)

Cattelan, Mattia, E-mail: mattia.cattelan.1@studenti.unipd.it; Artiglia, Luca; Favaro, Marco; Agnoli, Stefano, E-mail: mattia.cattelan.1@studenti.unipd.it; Granozzi, Gaetano [Department of Chemical Sciences, University of Padova, via Marzolo 1, 35135, Padova (Italy); Peng, Guowen; Roling, Luke T.; Mavrikakis, Manos [Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706 (United States); Cavaliere, Emanuele; Gavioli, Luca [Interdisciplinary Laboratories for Advanced Materials Physics (i-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica, via dei Musei 41, I-25121 Brescia (Italy); Barinov, Alexey [Sincrotrone Trieste S.C.p.A., Area Science Park-Basovizza, Strada Statale 14 Km 163.5, I-34149 Trieste (Italy); Píš, Igor [Sincrotrone Trieste S.C.p.A., Area Science Park-Basovizza, Strada Statale 14 Km 163.5, I-34149 Trieste (Italy); Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park-Basovizza, Strada Statale 14 Km 163.5, I-34149 Trieste (Italy); Nappini, Silvia; Magnano, Elena; Bondino, Federica [Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park-Basovizza, Strada Statale 14 Km 163.5, I-34149 Trieste (Italy)

2016-07-27

The emerging fields of graphene-based magnetic and spintronic devices require a deep understanding of the interface between graphene and ferromagnetic metals. This work reports a detailed investigation at the nanometer level of the Fe–graphene interface carried out by angle-resolved photoemission, high-resolution photoemission from core levels, and scanning tunnelling microscopy. Quasi-freestanding graphene was grown on Pt(111), and the iron film was either deposited atop or intercalated beneath graphene. Calculations and experimental results show that iron strongly modifies the graphene band structure and lifts its π band spin degeneracy.

Liquidity and International Trade

OpenAIRE

Rodriguez-Lopez, Antonio

2016-01-01

This paper introduces a framework to study the links between the supply of liquid assets for the financial market and the international allocation of economic activity. Private assets’ liquidity properties - their usefulness as collateral or media of exchange in financial transactions - affect assets’ values and interest rates, with consequences on firm entry, production, aggregate productivity, and total market capitalization. In a closed economy, the liquidity market increases the size and ...

A Moving Optical Fibre Technique for Structure Analysis of Heterogenous Products: Application to the Determination of the Bubble-Size Distribution in Liquid Foams

OpenAIRE

Bisperink, C. G. J.; Akkerman, J. C.; Prins, A.; Ronteltap, A. D.

1992-01-01

The bubble-size distribution in liquid foams measured as a function of time can be used to distinguish between the physical processes that determine the breakdown of foams. A new method based on an optical fibre technique was developed to measure various foam characteristics e.g. the rate of drainage, the rate of foam collapse, the change in gas fraction, interbubble gas diffusion (disproportionation) and the evolution of the bubble - size distribution during the ageing of the foam. The metho...

Size Controlled Synthesis of Transition Metal Nanoparticles for Catalytic Applications

KAUST Repository

Esparza, Angel

2011-07-07

Catalysis offers cleaner and more efficient chemical reactions for environmental scientists. More than 90% of industrial processes are performed with a catalyst involved, however research it is still required to improve the catalyst materials. The purpose of this work is to contribute with the development of catalysts synthesis with two different approaches. First, the precise size control of non-noble metals nanoparticles. Second, a new one-pot synthesis method based on a microemulsion system was developed to synthesize size-controlled metal nanoparticles in oxide supports. The one-pot method represents a simple approach to synthesize both support and immobilized nanometer-sized non-noble metal nanoparticles in the same reaction system. Narrow size distribution nickel, cobalt, iron and cobalt-nickel nanoparticles were obtained. High metal dispersions are attainable regardless the metal or support used in the synthesis. Thus, the methodology is adaptable and robust. The sizecontrolled supported metal nanoparticles offer the opportunity to study size effects and metal-support interactions on different catalytic reactions with different sets of metals and supports.

Synthesis of Nanometer-Sized Poly (methyl methacrylate) Polymer Network by Gold Nanoparticle Template

Science.gov (United States)

Liu, Fu-Ken; Hsieh, Shang-Yu; Ko, Fu-Hsiang; Chu, Tieh-Chi; Dai, Bau-Tong

2003-06-01

Gold nanoparticle/polymer composites have been produced using a one-system polymer synthesis. The linear polymer, poly (methyl methacrylate) (PMMA, MW = 15,000 g/mol) is applied for the stabilization of gold nanoparticles. The Fourier transfer infrared (FT-IR) analysis data and transition electron microscopy (TEM) image reveal that the core shell structure of gold/PMMA nanocomposite has been synthesized. The ratio of the concentration of the capping polymer material to the concentration of the gold precursor could control the sizes of gold nanoparticles. With specific concentration of the reductant, the core-shell nanostructure could be fluctuated in order. After heating treatment, the network structure of PMMA capped gold nanoparticles could be synthesized as confirmed by the TEM image. The result indicates that PMMA not only acts as the stabilizer, but also as the bridge of the neighboring gold nanoparticles.

Study of nanometer-level precise phase-shift system used in electronic speckle shearography and phase-shift pattern interferometry

Science.gov (United States)

Jing, Chao; Liu, Zhongling; Zhou, Ge; Zhang, Yimo

2011-11-01

The nanometer-level precise phase-shift system is designed to realize the phase-shift interferometry in electronic speckle shearography pattern interferometry. The PZT is used as driving component of phase-shift system and translation component of flexure hinge is developed to realize micro displacement of non-friction and non-clearance. Closed-loop control system is designed for high-precision micro displacement, in which embedded digital control system is developed for completing control algorithm and capacitive sensor is used as feedback part for measuring micro displacement in real time. Dynamic model and control model of the nanometer-level precise phase-shift system is analyzed, and high-precision micro displacement is realized with digital PID control algorithm on this basis. It is proved with experiments that the location precision of the precise phase-shift system to step signal of displacement is less than 2nm and the location precision to continuous signal of displacement is less than 5nm, which is satisfied with the request of the electronic speckle shearography and phase-shift pattern interferometry. The stripe images of four-step phase-shift interferometry and the final phase distributed image correlated with distortion of objects are listed in this paper to prove the validity of nanometer-level precise phase-shift system.

Measurement of liquid mixing characteristics in large-sized ion exchange column for isotope separation by stepwise response method

International Nuclear Information System (INIS)

Fujine, Sachio; Saito, Keiichiro; Iwamoto, Kazumi; Itoi, Toshiaki.

1981-07-01

Liquid mixing in a large-sized ion exchange column for isotope separation was measured by the step-wise response method, using NaCl solution as tracer. A 50 cm diameter column was packed with an ion exchange resin of 200 μm in mean diameter. Experiments were carried out for several types of distributor and collector, which were attached to each end of the column. The smallest mixing was observed for the perforated plate type of the collector, coupled with a minimum stagnant volume above the ion exchange resin bed. The 50 cm diameter column exhibited the better characteristics of liquid mixing than the 2 cm diameter column for which the good performance of lithium isotope separation had already been confirmed. These results indicate that a large increment of throughput is attainable by the scale-up of column diameter with the same performance of isotope separation as for the 2 cm diameter column. (author)

ANALISIS OPINION SHOPPING, SIZE, LIQUIDITY, KUALITAS AUDIT TERHADAP OPINI AUDIT GOING CONCERN PADA PERUSAHAAN MANUFAKTUR SEKTOR TEKSTIL DAN GARMENT YANG TERDAFTAR DI BEI TAHUN 2010-2013

Directory of Open Access Journals (Sweden)

Kevin Martio

2014-03-01

Full Text Available Opini audit yang diberikan oleh auditor merupakan informasi penting bagi pengguna laporan keuangan Tujuan dari penelitian ini adalah untuk mendapatkan bukti empiris mengenai beberapa faktor yang dapat digunakan untuk memprediksi probabilitas opini audit going concern. Variable yang digunakan dalam penelitian ini adalah opinion shopping, size, liquidity, dan kualitas audit. Studi ini pada perusahaan manufaktur sektor tekstil dan garment yang listing di BEI periode 2010-2013. Metode pengambilan Sampel penelitian yang digunakan dalam penelitian ini adalah metode purposive sampling dengan 60 sampel yang telah mengalami pengamatan selama 4 tahun. Teknik analisis yang digunakan yaitu dengan regresi logistik. Penelitian ini membuktikan bahwa opinion shopping, size, dan liquidity berpengaruh negatif terhadap opini audit going concern dan dan kualitas audit berpengaruh positif terhadap opini audit going concern.

Preparation of size-controlled (30-100 nm) magnetite nanoparticles for biomedical applications

International Nuclear Information System (INIS)

Nishio, K.; Ikeda, M.; Gokon, N.; Tsubouchi, S.; Narimatsu, H.; Mochizuki, Y.; Sakamoto, S.; Sandhu, A.; Abe, M.; Handa, H.

2007-01-01

Size-controlled magnetite nanoparticles (MNPs) with several dozen nanometers (nm) were synthesized for biomedical applications. Nanoparticles of single-phase magnetite, as revealed by X-ray analyses and magnetic measurements, were prepared by oxidizing ferrous hydroxide (Fe(OH) 2 ) with a weak oxidant NaNO 3 in an N 2 -deaerated aqueous NaOH solution (pH=12-13) at various temperatures below 37 deg. C. As the synthesis temperature increases from 4 to 37 deg. C, the MNPs are decreased in size (d) from 102±5.6 to 31.7±4.9 nm and widened in size distribution, Δd/d increases from 5.5% to 15%. Prepared without using any surfactant, the MNPs are advantageous for immobilizing functional molecules stably on the surfaces for biomedical applications

Designing artificial 2D crystals with site and size controlled quantum dots.

Science.gov (United States)

Xie, Xuejun; Kang, Jiahao; Cao, Wei; Chu, Jae Hwan; Gong, Yongji; Ajayan, Pulickel M; Banerjee, Kaustav

2017-08-30

Ordered arrays of quantum dots in two-dimensional (2D) materials would make promising optical materials, but their assembly could prove challenging. Here we demonstrate a scalable, site and size controlled fabrication of quantum dots in monolayer molybdenum disulfide (MoS 2 ), and quantum dot arrays with nanometer-scale spatial density by focused electron beam irradiation induced local 2H to 1T phase change in MoS 2 . By designing the quantum dots in a 2D superlattice, we show that new energy bands form where the new band gap can be controlled by the size and pitch of the quantum dots in the superlattice. The band gap can be tuned from 1.81 eV to 1.42 eV without loss of its photoluminescence performance, which provides new directions for fabricating lasers with designed wavelengths. Our work constitutes a photoresist-free, top-down method to create large-area quantum dot arrays with nanometer-scale spatial density that allow the quantum dots to interfere with each other and create artificial crystals. This technique opens up new pathways for fabricating light emitting devices with 2D materials at desired wavelengths. This demonstration can also enable the assembly of large scale quantum information systems and open up new avenues for the design of artificial 2D materials.

Recommendations for plutonium colloid size determination

International Nuclear Information System (INIS)

Kosiewicz, S.T.

1984-02-01

This report presents recommendations for plutonium colloid size determination and summarizes a literature review, discussions with other researchers, and comments from equipment manufacturers. Four techniques suitable for plutonium colloid size characterization are filtration and ultrafiltration, gel permeation chromatography, diffusion methods, and high-pressure liquid chromatography (conditionally). Our findings include the following: (1) Filtration and ultrafiltration should be the first methods used for plutonium colloid size determination because they can provide the most rapid results with the least complicated experimental arrangement. (2) After expertise has been obtained with filtering, gel permeation chromatography should be incorporated into the colloid size determination program. (3) Diffusion methods can be used next. (4) High-pressure liquid chromatography will be suitable after appropriate columns are available. A plutonium colloid size characterization program with filtration/ultrafiltration and gel permeation chromatography has been initiated

Sub-nanometer periodic nonlinearity error in absolute distance interferometers

Science.gov (United States)

Yang, Hongxing; Huang, Kaiqi; Hu, Pengcheng; Zhu, Pengfei; Tan, Jiubin; Fan, Zhigang

2015-05-01

Periodic nonlinearity which can result in error in nanometer scale has become a main problem limiting the absolute distance measurement accuracy. In order to eliminate this error, a new integrated interferometer with non-polarizing beam splitter is developed. This leads to disappearing of the frequency and/or polarization mixing. Furthermore, a strict requirement on the laser source polarization is highly reduced. By combining retro-reflector and angel prism, reference and measuring beams can be spatially separated, and therefore, their optical paths are not overlapped. So, the main cause of the periodic nonlinearity error, i.e., the frequency and/or polarization mixing and leakage of beam, is eliminated. Experimental results indicate that the periodic phase error is kept within 0.0018°.

A modified free-volume-based model for predicting vapor-liquid and solid-liquid equilibria for size asymmetric systems

DEFF Research Database (Denmark)

Radfarnia, H.R.; Ghotbi, C.; Taghikhani, V.

2005-01-01

The main purpose of this work is to present a free-volume combinatorial term in predicting vapor-liquid equilibrium (VLE) and solid-liquid equilibrium (SLE) of polymer/solvent and light and heavy hydrocarbon/hydrocarbon mixtures. The proposed term is based on a modification of the original Freed ...

Size-controlled synthesis of chalcogen and chalcogenide nanoparticles using protic ionic liquids with imidazolium cation

International Nuclear Information System (INIS)

Meenatchi, Boominathan; Renuga, Velayutham; Manikandan, Ayyar

2016-01-01

Green synthesis of selenium (chalcogen) nanoparticles (SeNPs) has been successfully attained by simple wet chemical method that involves the reaction of six different protic ionic liquids with imidazolium cations and sodium hydrogen selenide (NaHSe) in the presence of poly ethylene glycol-600 (PEG-600) as an additional stabilizer. The obtained SeNPs were characterized using UV spectral (UV), Fourier transform infra-red (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscope (SEM) with energy dispersive X-ray (EDX) and high resolution transmission electron microscope (TEM) analysis. The results illustrate that the synthesized SeNPs are spherical in shape with size ranging 19-24 nm and possess good optical property with greater band gap energy, high thermal stability up to 330 .deg. C, low melting point of 218-220 .deg. C comparing to precursor selenium. Using the synthesized SeNPs, two chalcogenides such as ZnSe and CdSe semiconductor nanoparticles were synthesized and characterized using XRD, SEM with EDX and TEM analysis. The fabricated CdSe and ZnSe nanoparticles appeared like pebble and cluster structure with particle size of 29.97 nm and 22.73 nm respectively.

Size-controlled synthesis of chalcogen and chalcogenide nanoparticles using protic ionic liquids with imidazolium cation

Energy Technology Data Exchange (ETDEWEB)

Meenatchi, Boominathan [Cauvery College for Women, Tamilnadu (India); Renuga, Velayutham [National College, Tamilnadu (India); Manikandan, Ayyar [Bharath Institute of Higher Education and Research, Bharath University, Tamilnadu (India)

2016-03-15

Green synthesis of selenium (chalcogen) nanoparticles (SeNPs) has been successfully attained by simple wet chemical method that involves the reaction of six different protic ionic liquids with imidazolium cations and sodium hydrogen selenide (NaHSe) in the presence of poly ethylene glycol-600 (PEG-600) as an additional stabilizer. The obtained SeNPs were characterized using UV spectral (UV), Fourier transform infra-red (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscope (SEM) with energy dispersive X-ray (EDX) and high resolution transmission electron microscope (TEM) analysis. The results illustrate that the synthesized SeNPs are spherical in shape with size ranging 19-24 nm and possess good optical property with greater band gap energy, high thermal stability up to 330 .deg. C, low melting point of 218-220 .deg. C comparing to precursor selenium. Using the synthesized SeNPs, two chalcogenides such as ZnSe and CdSe semiconductor nanoparticles were synthesized and characterized using XRD, SEM with EDX and TEM analysis. The fabricated CdSe and ZnSe nanoparticles appeared like pebble and cluster structure with particle size of 29.97 nm and 22.73 nm respectively.

Nanometal Skin of Plasmonic Heterostructures for Highly Efficient Near-Field Scattering Probes

Science.gov (United States)

Zito, Gianluigi; Rusciano, Giulia; Vecchione, Antonio; Pesce, Giuseppe; di Girolamo, Rocco; Malafronte, Anna; Sasso, Antonio

2016-08-01

In this work, atomic force microscopy probes are functionalized by virtue of self-assembling monolayers of block copolymer (BCP) micelles loaded either with clusters of silver nanoparticles or bimetallic heterostructures consisting of mixed species of silver and gold nanoparticles. The resulting self-organized patterns allow coating the tips with a sort of nanometal skin made of geometrically confined nanoislands. This approach favors the reproducible engineering and tuning of the plasmonic properties of the resulting structured tip by varying the nanometal loading of the micelles. The newly conceived tips are applied for experiments of tip-enhanced Raman scattering (TERS) spectroscopy and scattering-type scanning near-field optical microscopy (s-SNOM). TERS and s-SNOM probe characterizations on several standard Raman analytes and patterned nanostructures demonstrate excellent enhancement factor with the possibility of fast scanning and spatial resolution <12 nm. In fact, each metal nanoisland consists of a multiscale heterostructure that favors large scattering and near-field amplification. Then, we verify the tips to allow challenging nongap-TER spectroscopy on thick biosamples. Our approach introduces a synergistic chemical functionalization of the tips for versatile inclusion and delivery of plasmonic nanoparticles at the tip apex, which may promote the tuning of the plasmonic properties, a large enhancement, and the possibility of adding new degrees of freedom for tip functionalization.

Decoherence and Entanglement Simulation in a Model of Quantum Neural Network Based on Quantum Dots

Directory of Open Access Journals (Sweden)

Altaisky Mikhail V.

2016-01-01

Full Text Available We present the results of the simulation of a quantum neural network based on quantum dots using numerical method of path integral calculation. In the proposed implementation of the quantum neural network using an array of single-electron quantum dots with dipole-dipole interaction, the coherence is shown to survive up to 0.1 nanosecond in time and up to the liquid nitrogen temperature of 77K.We study the quantum correlations between the quantum dots by means of calculation of the entanglement of formation in a pair of quantum dots on the GaAs based substrate with dot size of 100 ÷ 101 nanometer and interdot distance of 101 ÷ 102 nanometers order.

High-activity liquid packaging design criteria

International Nuclear Information System (INIS)

1994-05-01

In recent studies, it has been acknowledged that there is an emerging need for packaging to transport high-activity liquid off the Hanford Site to support characterization and process development activities of liquid waste stored in underground tanks. These studies have dealt with specimen testing needs primarily at the Hanford Site; however, similar needs appear to be developing at other US Department of Energy (DOE) sites. The need to ship single and multiple specimens to offsite laboratories is anticipated because it is predicted that onsite laboratories will be overwhelmed by an increasing number and size (volume) of samples. Potentially, the specimen size could range from 250 mL to greater than 50 L. Presently, no certified Type-B packagings are available for transport of high-activity liquid radioactive specimens in sizes to support Site missions

Effect of Energy Polydispersity on the Nature of Lennard-Jones Liquids

OpenAIRE

Ingebrigtsen, Trond S.; Tanaka, Hajime

2016-01-01

In the companion paper [T. S. Ingebrigtsen and H. Tanaka, J. Phys. Chem. B 119, 11052 (2015)] the effect of size polydispersity on the nature of Lennard-Jones (LJ) liquids, which represent most molecular liquids without hydrogen bonds, was studied. More specifically, it was shown that even highly size polydisperse LJ liquids are Roskilde-simple (RS) liquids. RS liquids are liquids with strong correlation between constant volume equilibrium fluctuations of virial and potential energy and are s...

Study of vibrations and stabilization of linear collider final doublets at the sub-nanometer scale; Etude des vibrations et de la stabilisation a l'echelle sous-nanometrique des doublets finaux d'un collisionneur lineaire

Energy Technology Data Exchange (ETDEWEB)

Bolzon, B

2007-11-15

CLIC is one of the current projects of high energy linear colliders. Vertical beam sizes of 0.7 nm at the time of the collision and fast ground motion of a few nanometers impose an active stabilization of the final doublets at a fifth of nanometer above 4 Hz. The majority of my work concerned vibrations and active stabilization study of cantilever and slim beams in order to be representative of the final doublets of CLIC. In a first part, measured performances of different types of vibration sensors associated to an appropriate instrumentation showed that accurate measurements of ground motion are possible from 0.1 Hz up to 2000 Hz on a quiet site. Also, electrochemical sensors answering a priori the specifications of CLIC can be incorporated in the active stabilization at a fifth of nanometer. In a second part, an experimental and numerical study of beam vibrations enabled to validate the efficiency of the numerical prediction incorporated then in the simulation of the active stabilization. Also, a study of the impact of ground motion and of acoustic noise on beam vibrations showed that an active stabilization is necessary at least up to 1000 Hz. In a third part, results on the active stabilization of a beam at its two first resonances are shown down to amplitudes of a tenth of nanometer above 4 Hz by using in parallel a commercial system performing passive and active stabilization of the clamping. The last part is related to a study of a support for the final doublets of a linear collider prototype in phase of finalization, the ATF2 prototype. This work showed that relative motion between this support and the ground is below imposed tolerances (6 nm above 0.1 Hz) with appropriate boundary conditions. (author)

Liquid-liquid interface assisted synthesis of size- and thickness-controlled Ag nanoplates

International Nuclear Information System (INIS)

Jin Mingshang; Kuang Qin; Han Xiguang; Xie Shuifen; Xie Zhaoxiong; Zheng Lansun

2010-01-01

Here we proposed a synthetic method of high-purity Ag nanoplates by the reduction of aqueous Ag + ions at the aqueous-organic interface with the reductant ferrocene. We demonstrated that the as-prepared Ag nanoplates can be widely tunable from 600 nm to 7 μm in size and from 10 to 35 nm in thickness, simply by adjusting the component of organic phase. To our knowledge, there are few methods to tailor the size and the thickness of metal nanoplates in such a large range although many efforts have been made aiming to realize it. Our proposed synthetic strategy is rapid, template-free, seed-less, and high-yield, and could be applied to synthesize analogous two-dimensional nanostructures of other noble metals, such as Pt, Au, and Pd. - Graphical abstract: High-purity Ag nanoplates were synthesized by the reduction of aqueous Ag + ions at the aqueous-organic interface with the reductant ferrocene, the size and thickness of which were widely tunable.

Resolving three-dimensional shape of sub-50 nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

International Nuclear Information System (INIS)

Attota, Ravikiran; Dixson, Ronald G.

2014-01-01

We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30 nm–40 nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22 nm (k = 2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

Comparison between XAS, AWAXS and DAFS applied to nanometer scale supported metallic clusters. Pt.1; monometallic clusters

International Nuclear Information System (INIS)

Bazin, D.C.; Sayers, D.A.

1993-01-01

The structural information found using three techniques related to synchrotron radiation are compared. XAS (X-ray Absorption Spectroscopy), AWAXS (Anomalous Wide Angle X-ray Scattering) and DAFS (Diffraction Anomalous Fine Structure) are applied to nanometer scale metallic clusters. (author)

Contact stiffness and damping of liquid films in dynamic atomic force microscope

International Nuclear Information System (INIS)

Xu, Rong-Guang; Leng, Yongsheng

2016-01-01

The mechanical properties and dissipation behaviors of nanometers confined liquid films have been long-standing interests in surface force measurements. The correlation between the contact stiffness and damping of the nanoconfined film is still not well understood. We establish a novel computational framework through molecular dynamics (MD) simulation for the first time to study small-amplitude dynamic atomic force microscopy (dynamic AFM) in a simple nonpolar liquid. Through introducing a tip driven dynamics to mimic the mechanical oscillations of the dynamic AFM tip-cantilever assembly, we find that the contact stiffness and damping of the confined film exhibit distinct oscillations within 6-7 monolayer distances, and they are generally out-of-phase. For the solid-like film with integer monolayer thickness, further compression of the film before layering transition leads to higher stiffness and lower damping, while much lower stiffness and higher damping occur at non-integer monolayer distances. These two alternating mechanisms dominate the mechanical properties and dissipation behaviors of simple liquid films under cyclic elastic compression and inelastic squeeze-out. Our MD simulations provide a direct picture of correlations between the structural property, mechanical stiffness, and dissipation behavior of the nanoconfined film.

Nanoscale discontinuities at the boundary of flowing liquids: a look into structure

International Nuclear Information System (INIS)

Wolff, Max; Gutfreund, Philipp; Zabel, Hartmut; Ruehm, Adrian; Akgun, Bulent

2011-01-01

When downsizing technology, confinement and interface effects become enormously important. Shear imposes additional anisotropy on a liquid. This may induce inhomogeneities, which may have their origin close to the solid interface. For advancing the understanding of flow, information on structures on all length scales and in particular close to the solid interface is indispensable. Neutron scattering offers an excellent tool to contribute in this context. In this work, surface sensitive scattering techniques were used to resolve the structure of liquids under flow in the vicinity of a solid interface. Our results are summarized as follows. First, for a Newtonian liquid we report a depletion distance on the order of nanometers which is far too small to explain the amount of surface slip, on the order of micrometers, found by complementary techniques. Second, for a grafted polymer brush we find no entanglement-disentanglement transition under shear but the grafted film gets ripped off the surface. Third, by evaluating the local structure factor of a micellar solution close to the solid interface it turns out that the degree of order and local relaxation depends critically on the surface energy of the solid surface.

Contact stiffness and damping of liquid films in dynamic atomic force microscope

Energy Technology Data Exchange (ETDEWEB)

Xu, Rong-Guang; Leng, Yongsheng, E-mail: leng@gwu.edu [Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC 20052 (United States)

2016-04-21

The mechanical properties and dissipation behaviors of nanometers confined liquid films have been long-standing interests in surface force measurements. The correlation between the contact stiffness and damping of the nanoconfined film is still not well understood. We establish a novel computational framework through molecular dynamics (MD) simulation for the first time to study small-amplitude dynamic atomic force microscopy (dynamic AFM) in a simple nonpolar liquid. Through introducing a tip driven dynamics to mimic the mechanical oscillations of the dynamic AFM tip-cantilever assembly, we find that the contact stiffness and damping of the confined film exhibit distinct oscillations within 6-7 monolayer distances, and they are generally out-of-phase. For the solid-like film with integer monolayer thickness, further compression of the film before layering transition leads to higher stiffness and lower damping, while much lower stiffness and higher damping occur at non-integer monolayer distances. These two alternating mechanisms dominate the mechanical properties and dissipation behaviors of simple liquid films under cyclic elastic compression and inelastic squeeze-out. Our MD simulations provide a direct picture of correlations between the structural property, mechanical stiffness, and dissipation behavior of the nanoconfined film.

A new capacitive long-range displacement nanometer sensor with differential sensing structure based on time-grating

Science.gov (United States)

Yu, Zhicheng; Peng, Kai; Liu, Xiaokang; Pu, Hongji; Chen, Ziran

2018-05-01

High-precision displacement sensors, which can measure large displacements with nanometer resolution, are key components in many ultra-precision fabrication machines. In this paper, a new capacitive nanometer displacement sensor with differential sensing structure is proposed for long-range linear displacement measurements based on an approach denoted time grating. Analytical models established using electric field coupling theory and an area integral method indicate that common-mode interference will result in a first-harmonic error in the measurement results. To reduce the common-mode interference, the proposed sensor design employs a differential sensing structure, which adopts a second group of induction electrodes spatially separated from the first group of induction electrodes by a half-pitch length. Experimental results based on a prototype sensor demonstrate that the measurement accuracy and the stability of the sensor are substantially improved after adopting the differential sensing structure. Finally, a prototype sensor achieves a measurement accuracy of  ±200 nm over the full 200 mm measurement range of the sensor.

Size effect of the elastic modulus of rectangular nanobeams: Surface elasticity effect

International Nuclear Information System (INIS)

Yao Hai-Yan; Fan Wen-Liang; Yun Guo-Hong

2013-01-01

The size-dependent elastic property of rectangular nanobeams (nanowires or nanoplates) induced by the surface elasticity effect is investigated by using a developed modified core-shell model. The effect of surface elasticity on the elastic modulus of nanobeams can be characterized by two surface related parameters, i.e., inhomogeneous degree constant and surface layer thickness. The analytical results show that the elastic modulus of the rectangular nanobeam exhibits a distinct size effect when its characteristic size reduces below 100 nm. It is also found that the theoretical results calculated by a modified core-shell model have more obvious advantages than those by other models (core-shell model and core-surface model) by comparing them with relevant experimental measurements and computational results, especially when the dimensions of nanostructures reduce to a few tens of nanometers. (condensed matter: structural, mechanical, and thermal properties)

Confinement of surface waves at the air-water interface to control aerosol size and dispersity

Science.gov (United States)

Nazarzadeh, Elijah; Wilson, Rab; King, Xi; Reboud, Julien; Tassieri, Manlio; Cooper, Jonathan M.

2017-11-01

The precise control over the size and dispersity of droplets, produced within aerosols, is of great interest across many manufacturing, food, cosmetic, and medical industries. Amongst these applications, the delivery of new classes of high value drugs to the lungs has recently attracted significant attention from pharmaceutical companies. This is commonly achieved through the mechanical excitation of surface waves at the air liquid interface of a parent liquid volume. Previous studies have established a correlation between the wavelength on the surface of liquid and the final aerosol size. In this work, we show that the droplet size distribution of aerosols can be controlled by constraining the liquid inside micron-sized cavities and coupling surface acoustic waves into different volumes of liquid inside micro-grids. In particular, we show that by reducing the characteristic physical confinement size (i.e., either the initial liquid volume or the cavities' diameters), higher harmonics of capillary waves are revealed with a consequent reduction of both aerosol mean size and dispersity. In doing so, we provide a new method for the generation and fine control of aerosols' sizes distribution.

Preparation of submicron-sized spherical particles of gold using laser-induced melting in liquids and low-toxic stabilizing reagent

International Nuclear Information System (INIS)

Tsuji, T.; Higashi, Y.; Tsuji, M.; Ishikawa, Y.; Koshizaki, N.

2015-01-01

Highlights: • Submicron-sized spherical particles of gold were prepared using laser irradiation for the source gold nanoparticles stabilized by NaCl. • The source gold nanoparticles agglomeration was controlled both by the NaCl concentration of and by laser irradiation. • The formation process and the laser-fluence dependence of the particle size of gold nanoparticles in NaCl solutions differs from those in citrate solutions. • We revealed that properties of ligands are significantly important to prepare submicron-sized spherical particles and to control their size. - Abstract: Laser-induced melting in liquids (LIML) was applied to prepare spherical submicron-sized particles of gold (AuSMPs) from gold nanoparticles (AuNPs) stabilized using NaCl. Because undesirable byproducts, which might be generated when organic reagents such as citrate are used as the stabilizing reagent, are not generated from NaCl by laser irradiation, AuSMPs fabricated from AuNPs stabilized by NaCl will be low toxic. The AuSMPs were obtained by laser irradiation of the source AuNPs in NaCl solutions stabilized by NaCl at the proper concentration. Similar to the preparation of AuSMPs from AuNPs stabilized by citrate, the agglomeration of the source AuNPs, which is necessary to obtain AuSMPs, was controlled both by the NaCl concentration and by laser irradiation. However, the formation process and the laser-fluence dependence of the particle size of AuSMPs differed for various NaCl solutions and citrate solutions

Ionic cluster size distributions of swollen nafion/sulfated beta-cyclodextrin membranes characterized by nuclear magnetic resonance cryoporometry.

Science.gov (United States)

Jeon, Jae-Deok; Kwak, Seung-Yeop

2007-08-16

Nafion/sb-CD membranes were prepared by mixing 5 wt% Nafion solution with H+-form sulfated beta-cyclodextrin (sb-CD), and their water uptakes, ion exchange capacities (IECs), and ionic cluster size distributions were measured. Gravimetric and thermogravimetric measurements showed that the water uptake of the membranes increased with increases in their sb-CD content. The IECs of the membrane were measured with acid-base titration and found to increase with increases in the sb-CD content, reaching 0.96 mequiv/g for NC5 ("NCx" denotes a Nafion/sb-CD composite membrane containing x wt% of sb-CD). The cluster-correlation peaks and ionic cluster size distributions of the water-swollen membranes were determined using small-angle X-ray scattering (SAXS) and 1H nuclear magnetic resonance (NMR) cryoporometry, respectively. The SAXS experiments confirmed that increases in the sb-CD content of the membranes shifted the maximum SAXS peaks to lower angles, indicating an increase in the cluster correlation peak. NMR cryoporometry is based on the theory of the melting point depression, Delta Tm, of a liquid confined within a pore, which is dependent on the pore diameter. The melting point depression was determined by analyzing the variation of the NMR signal intensity with temperature. Our analysis of the intensity-temperature (IT) curves showed that the ionic cluster size distribution gradually became broader with increases in the membrane sb-CD content due to the increased water content, indicating an increase in the ionic cluster size. This result indicates that the presence of sb-CD with its many sulfonic acid sites in the Nafion membranes results in increases in the ionic cluster size as well as in the water uptake and the IEC. We conclude that NMR cryoporometry provides a method for determining the ionic cluster size on the nanometer scale in an aqueous environment, which cannot be obtained using other methods.

Effect of diffusion losses on the size growth of nanoparticles by coagulation

Directory of Open Access Journals (Sweden)

Alonso, M.

1998-05-01

Full Text Available The size growth rate of aerosol particles by Brownian coagulation is significantly reduced in the case of nanometer-sized particles, for which deposition losses are extremely high. A simplified model, assuming that the coagulation rate constant and the deposition loss rate constant are both independent of particle size, is proposed. The size growth rate reduction predicted by the model is in very good agreement with the experimental results.

La velocidad de crecimiento de partículas de aerosol por coagulación browniana se reduce considerablemente en el caso de nanopartículas, para las que las pérdidas por difusión son extremadamente altas. Se propone un modelo simplificado en el que las constantes de velocidad, tanto de coagulación como de pérdida por difusión, se suponen independientes del tamaño de partícula. Las predicciones del modelo están en buen acuerdo con los resultados experimentales.

Size and Velocity Distributions of Particles and Droplets in Spray Combustion Systems.

Science.gov (United States)

1984-11-01

34Particle Sizing by Optical , Nonimaging Techniques," Liquid Particle Size _Mjur-mentTechnjgjwi, ASTM publications STP848, ed. by J. MI. Tishkoff, R. D... Optical Nonimaging predictions do not account for nonideal lens effects. Techniques," in Liquid Particle Size Measurement Techniques, J.M.Tishkoff, ed...4S E. Dan Hirleman’ Particle Sizing by Optical , Nonimaging Techniques REFERENCE: Hieleman, E. D., "Particle Sizing by Optical , Nonimaging Tech- niques

Enhanced Laser Cooling of Rare-Earth-Ion-Doped Glass Containing Nanometer-Sized Metallic Particles

International Nuclear Information System (INIS)

Jia Youhua; Zhong Biao; Yin Jianping

2009-01-01

The enhanced laser cooling performance of rare-earth-ions-doped glasses containing small particles is predicted. This is achieved by the enhancement of local field around rare earth ions, owing to the surface plasmon resonance of small metallic particles. The role of energy transfer between ions and the particle is theoretical discussed. Depending on the particle size and the ion emission quantum efficiency, the enhancement of the absorption and the fluorescence is predicted. Moreover, taking Yb 3+ -doped ZBLAN as example, the cooling power and heat-light converting efficiency are calculated. It is finally concluded that the absorption and the fluorescence are greatly enhanced in these composite materials, the cooling power is increased compared to the bulk material. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Comparison between XAS, AWAXS and DAFS applied to nanometer scale supported metallic clusters. Pt.2; bimetallic clusters

International Nuclear Information System (INIS)

Bazin, D.; Sayers, D.

1993-01-01

The structural information obtained using three techniques related to synchrotron radiation are compared. XAS (X-ray Absorption Spectroscopy), AWAXS (Anomalous Wide Angle X-ray Scattering) and DAFS (Diffraction Anomalous Fine Structure) are applied to the study of nanometer scale bimetallic clusters. (author)

Nanometer-resolution electron microscopy through micrometers-thick water layers

Energy Technology Data Exchange (ETDEWEB)

Jonge, Niels de, E-mail: niels.de.jonge@vanderbilt.edu [Vanderbilt University Medical Center, Department of Molecular Physiology and Biophysics, Nashville, TN 37232-0615 (United States); Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831-6064 (United States); Poirier-Demers, Nicolas; Demers, Hendrix [Universite de Sherbrooke, Electrical and Computer Engineering, Sherbrooke, Quebec J1K 2R1 (Canada); Peckys, Diana B. [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831-6064 (United States); University of Tennessee, Center for Environmental Biotechnology, Knoxville, TN 37996-1605 (United States); Drouin, Dominique [Universite de Sherbrooke, Electrical and Computer Engineering, Sherbrooke, Quebec J1K 2R1 (Canada)

2010-08-15

Scanning transmission electron microscopy (STEM) was used to image gold nanoparticles on top of and below saline water layers of several micrometers thickness. The smallest gold nanoparticles studied had diameters of 1.4 nm and were visible for a liquid thickness of up to 3.3 {mu}m. The imaging of gold nanoparticles below several micrometers of liquid was limited by broadening of the electron probe caused by scattering of the electron beam in the liquid. The experimental data corresponded to analytical models of the resolution and of the electron probe broadening as function of the liquid thickness. The results were also compared with Monte Carlo simulations of the STEM imaging on modeled specimens of similar geometry and composition as used for the experiments. Applications of STEM imaging in liquid can be found in cell biology, e.g., to study tagged proteins in whole eukaryotic cells in liquid and in materials science to study the interaction of solid:liquid interfaces at the nanoscale.

Mathematical model for prediction of droplet sizes and distribution associated with impact of liquid-containing projectile

International Nuclear Information System (INIS)

Shelke, Ashish V.; Gera, B.; Maheshwari, N.K.; Singh, R.K.

2018-01-01

After the events of 9/11, the impact of fast flying commercial aircraft is considered as major hazard threatening the Nuclear Power Plant's (NPP) safety. The study of fuel spillage phenomenon and fireball formation is important to understand fire hazards due to burning of dispersed aviation fuel. The detailed analysis of fuel dispersion is very difficult to deliberate because both, large NPP structures and the large size of commercial aircrafts. Sandia National Laboratories, USA conducted impact tests using cylindrical projectiles filled with water to measure the associated parameters. Due to combustion properties and volatile nature of hydrocarbon fuels, the obtained parameters from impact studies using water are incomplete in fire analysis of flammable droplet clouds. A mathematical model is developed for prediction of droplet sizes and distribution associated with the impact of a liquid-containing projectile. The model can predict the transient behavior of droplet cloud. It is validated with experimental data available in literature. In the present study, the analysis has been performed using water and kerosene. The data obtained can be utilized as boundary and initial condition for CFD analysis. This information is useful for fire hazard analysis of aircraft impacts on NPP structures.

Do Hedge Funds Supply or Demand Liquidity?

OpenAIRE

Petri Jylhä; Kalle Rinne; Matti Suominen

2014-01-01

Regressing hedge funds’ returns on returns to a long–short contrarian trading strategy, a measure of the returns from providing liquidity, we find that hedge funds typically supply liquidity in the stock market. In the cross-section, strict redemption restrictions and large fund size increase funds’ propensity to supply liquidity. In time series, poor market liquidity and good funding conditions increase funds’ propensity to supply liquidity. Although the hedge funds typically supply liquidit...

MICRON-SIZED POLYMER PARTICLES FROM TANZANIAN ...

African Journals Online (AJOL)

Micron sized polymeric particles were prepared from cashew nut shell liquid and subsequently functionalized to produce micron-sized carboxylated cation exchange resin (MCCER). By titrimetry and analytical procedures employing atomic absorption spectrometry, an assessment of the cation exchange capability of the ...

Effect of pieces size of Empty Fruit Bunches (EFB) on composting of EFB mixed with activated liquid organic fertilizer

Science.gov (United States)

Trisakti, B.; Mhardela, P.; Husaini, T.; Irvan; Daimon, H.

2018-02-01

This research was to determine the effect of pieces sizes of oil palm empty fruit bunch (EFB) on the composting of EFB mixed with activated liquid organic fertilizer (ALOF) in a basket composter in order to obtain high quality compost. The composting process was started by cutting the EFB into pieces with varies sizes, inserting the EFB pieces into basket composter (33 cm W × 28 cm L × 40 cm H), and adding ALOF until moisture content (MC) in the range of 55-65%. During composting, the compost pile was turned every 3 days and the MC was maintained at 55-65% range by adding the ALOF. The sizes of the EFB pieces were varied into <1, 1-3, 4-7, 8-11, and 12-15 cm. The parameters analysed during the composting were temperature, pH, MC, compost weight, water holding capacity (WHC), CN ratio, and the quality of the final compost. Composting was carried out for 40 days and the best result obtained at EFB pieces size was 1-3 cm with compost characteristic were pH 9.0; MC 52.59%; WHC 76%; CN ratio 12.15; N 1.96%; P 0.58%; and K 0. 95%.

Size and shape dependent lattice parameters of metallic nanoparticles

International Nuclear Information System (INIS)

Qi, W. H.; Wang, M. P.

2005-01-01

A model is developed to account for the size and shape dependent lattice parameters of metallic nanoparticles, where the particle shape difference is considered by introducing a shape factor. It is predicted that the lattice parameters of nanoparticles in several nanometers decrease with decreasing of the particle size, which is consistent with the corresponding experimental results. Furthermore, it is found that the particle shape can lead to 10% of the total lattice variation. The model is a continuous media model and can deal with the nanoparticles larger than 1 nm. Since the shape factor approaches to infinity for nanowires and nanofilms, therefore, the model cannot be generalized to the systems of nanowires and nanofilms. For the input parameters are physical constants of bulk materials, therefore, the present model may be used to predict the lattice variation of different metallic nanoparticles with different lattice structures

Liquid-solid phase transition of Ge-Sb-Te alloy observed by in-situ transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Berlin, Katja, E-mail: katja.berlin@pdi-berlin.de; Trampert, Achim

2017-07-15

Melting and crystallization dynamics of the multi-component Ge-Sb-Te alloy have been investigated by in-situ transmission electron microscopy (TEM). Starting point of the phase transition study is an ordered hexagonal Ge{sub 1}Sb{sub 2}Te{sub 4} thin film on Si(111) where the crystal structure and the chemical composition are verified by scanning TEM and electron energy-loss spectroscopy, respectively. The in-situ observation of the liquid phase at 600°C including the liquid-solid and liquid-vacuum interfaces and their movements was made possible due to an encapsulation of the TEM sample. The solid-liquid interface during melting displays a broad and diffuse transition zone characterized by a vacancy induced disordered state. Although the velocities of interface movements are measured to be in the nanometer per second scale, both, for crystallization and solidification, the underlying dynamic processes are considerably different. Melting reveals linear dependence on time, whereas crystallization exhibits a non-linear time-dependency featuring a superimposed start-stop motion. Our results may provide valuable insight into the atomic mechanisms at interfaces during the liquid-solid phase transition of Ge-Sb-Te alloys. - Highlights: • In-situ TEM observation of liquid Ge-Sb-Te phase transition due to encapsulation. • During melting: Observation of non-ordered interface transition due to premelting. • During solidification: Observation of non-linear time-dependent crystallization.

Liquid-solid phase transition of Ge-Sb-Te alloy observed by in-situ transmission electron microscopy

International Nuclear Information System (INIS)

Berlin, Katja; Trampert, Achim

2017-01-01

Melting and crystallization dynamics of the multi-component Ge-Sb-Te alloy have been investigated by in-situ transmission electron microscopy (TEM). Starting point of the phase transition study is an ordered hexagonal Ge 1 Sb 2 Te 4 thin film on Si(111) where the crystal structure and the chemical composition are verified by scanning TEM and electron energy-loss spectroscopy, respectively. The in-situ observation of the liquid phase at 600°C including the liquid-solid and liquid-vacuum interfaces and their movements was made possible due to an encapsulation of the TEM sample. The solid-liquid interface during melting displays a broad and diffuse transition zone characterized by a vacancy induced disordered state. Although the velocities of interface movements are measured to be in the nanometer per second scale, both, for crystallization and solidification, the underlying dynamic processes are considerably different. Melting reveals linear dependence on time, whereas crystallization exhibits a non-linear time-dependency featuring a superimposed start-stop motion. Our results may provide valuable insight into the atomic mechanisms at interfaces during the liquid-solid phase transition of Ge-Sb-Te alloys. - Highlights: • In-situ TEM observation of liquid Ge-Sb-Te phase transition due to encapsulation. • During melting: Observation of non-ordered interface transition due to premelting. • During solidification: Observation of non-linear time-dependent crystallization.

Preparation of nano-sized α-Al2O3 from oil shale ash

International Nuclear Information System (INIS)

An, Baichao; Wang, Wenying; Ji, Guijuan; Gan, Shucai; Gao, Guimei; Xu, Jijing; Li, Guanghuan

2010-01-01

Oil shale ash (OSA), the residue of oil shale semi-coke roasting, was used as a raw material to synthesize nano-sized α-Al 2 O 3 . Ultrasonic oscillation pretreatment followed by azeotropic distillation was employed for reducing the particle size of α-Al 2 O 3 . The structural characterization at molecular and nanometer scales was performed using X-ray diffraction (XRD), transmission electron microscopy (TEM), respectively. The interaction between alumina and n-butanol was characterized by Fourier transform infrared spectroscopy (FT-IR). The results revealed that the crystalline phase of alumina nanoparticles was regular and the well dispersed alumina nanoparticles had a diameter of 50-80 nm. In addition, the significant factors including injection rate of carbon oxide (CO 2 ), ultrasonic oscillations, azeotropic distillation and surfactant were investigated with respect to their effects on the size of the alumina particles.

Chemical-state-selective mapping at nanometer scale using synchrotron radiation and photoelectron emission microscopy

International Nuclear Information System (INIS)

Hirao, Norie; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori

2010-01-01

For surface analyses of semiconductor devices and various functional materials, it has become indispensable to analyze valence states at nanometer scale due to the rapid developments of nanotechnology. Since a method for microscopic mapping dependent on the chemical bond states has not been established so far, we have developed a photoelectron emission microscopy (PEEM) system combined with synchrotron soft X-ray excitation. The samples investigated were Si/SiO x micro-patterns prepared by O 2 + ion implantation in Si(001) wafer using a mask. PEEM images excited by various photon energies around the Si K-edge were observed. The lateral spatial resolution of the system was about 41 nm. The brightness of each spot in PEEM images changed depending on the photon energy, due to the X-ray absorption intensity of the respective chemical state. Since the surface of this sample was topographically flat, it has been demonstrated that the present method can be applied to observations of the microscopic pattern, depending not on the morphology, but only on the valence states of silicon. We have also in-situ measured the changes of the PEEM images upon annealing, and elucidated the mechanism of the lateral diffusion of oxygen and valence states of silicon at the nanometer scale. (author)

Chemical-state-selective mapping at nanometer scale using synchrotron radiation and photoelectron emission microscopy

International Nuclear Information System (INIS)

Hirao, Norie; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori

2008-01-01

For surface analyses of semiconductor devices and various functional materials, it has become indispensable to analyze the valence states at the nanometer scale due to the rapid developments of nanotechnology. Since a method for microscopic mapping dependent on the chemical bond states has not been established so far, we have developed a photoelectron emission microscopy (PEEM) system combined with synchrotron soft X-ray excitation. The samples investigated were Si/SiO x micro-patterns prepared by O 2 + ion implantation in a Si(001) wafer using a mask. PEEM images excited by various photon energies around the Si K-edge were observed. The lateral spatial resolution of the system was about 41 nm. The brightness of each spot in PEEM images changed depending on the photon energy, due to the X-ray absorption intensity of the respective chemical state. Since the surface of this sample is topographically flat, it has been demonstrated that the present method can be applied to observations of the microscopic pattern, depending not on the morphology, but only on the valence states of silicon. We have also in-situ measured the changes of PEEM images upon annealing, and elucidated the mechanism of the lateral diffusion of oxygen and valence states of silicon at the nanometer scale. (author)

Transverse excitations in liquid Fe, Cu and Zn

International Nuclear Information System (INIS)

Hosokawa, S; Inui, M; Kajihara, Y; Tsutsui, S; Baron, A Q R

2015-01-01

Transverse acoustic (TA) excitation modes were observed in inelastic x-ray scattering spectra of liquid Fe, Cu and Zn. From the analysis of current correlation functions, we concluded that TA excitation modes can experimentally be detected through the quasi-TA branches in the longitudinal current correlation spectra in these liquid metals. The microscopic elastic constants are estimated and a characteristic difference from macroscopic polycrystalline value was found in Poisson's ratio of liquid Fe, which shows an extremely softer value of ∼0.38 compared with the macroscopic value of ∼0.275. The lifetime of the TA modes were determined to be ∼0.45 ps for liquid Fe and Cu and ∼0.55 ps for liquid Zn, reflecting different interatomic correlations between liquid transition metals and non-transition metals. The propagation length of the TA modes are ∼0.85 nm in all of liquid metals, corresponding to the size of icosahedral or similar size of cages formed instantaneously in these liquid metals. (paper)

Nano sized bismuth oxy chloride by metal organic chemical vapour deposition

Energy Technology Data Exchange (ETDEWEB)

Jagdale, Pravin, E-mail: pravin.jagdale@polito.it [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy); Castellino, Micaela [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Marrec, Françoise [Laboratory of Condensed Matter Physics, University of Picardie Jules Verne (UPJV), Amiens 80039 (France); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexicom (UNAM), Mexico D.F. 04510 (Mexico); Tagliaferro, Alberto [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy)

2014-06-01

Metal organic chemical vapour deposition (MOCVD) method was used to prepare thin films of bismuth based nano particles starting from bismuth salts. Nano sized bismuth oxy chloride (BiOCl) crystals were synthesized from solution containing bismuth chloride (BiCl{sub 3}) in acetone (CH{sub 3}-CO-CH{sub 3}). Self-assembly of nano sized BiOCl crystals were observed on the surface of silicon, fused silica, copper, carbon nanotubes and aluminium substrates. Various synthesis parameters and their significant impact onto the formation of self-assembled nano-crystalline BiOCl were investigated. BiOCl nano particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Micro-Raman spectroscopy. These analyses confirm that bismuth nanometer-sized crystal structures showing a single tetragonal phase were indeed bismuth oxy chloride (BiOCl) square platelets 18–250 nm thick and a few micrometres wide.

Observation of propane cluster size distributions during nucleation and growth in a Laval expansion

Energy Technology Data Exchange (ETDEWEB)

Ferreiro, Jorge J.; Chakrabarty, Satrajit; Schläppi, Bernhard; Signorell, Ruth [Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich (Switzerland)

2016-12-07

We report on molecular-level studies of the condensation of propane gas and propane/ethane gas mixtures in the uniform (constant pressure and temperature) postnozzle flow of Laval expansions using soft single-photon ionization by vacuum ultraviolet light and mass spectrometric detection. The whole process, from the nucleation to the growth to molecular aggregates of sizes of several nanometers (∼5 nm), can be monitored at the molecular level with high time-resolution (∼3 μs) for a broad range of pressures and temperatures. For each time, pressure, and temperature, a whole mass spectrum is recorded, which allows one to determine the critical cluster size range for nucleation as well as the kinetics and mechanisms of cluster-size specific growth. The detailed information about the size, composition, and population of individual molecular clusters upon condensation provides unique experimental data for comparison with future molecular-level simulations.

Nanoconfined ionic liquids: Disentangling electrostatic and viscous forces

Science.gov (United States)

Lhermerout, Romain; Perkin, Susan

2018-01-01

Recent reports of surface forces across nanoconfined ionic liquids have revealed the existence of an anomalously long-ranged interaction apparently of electrostatic origin. Ionic liquids are viscous, and therefore it is important to inspect rigorously whether the observed repulsive forces are indeed equilibrium forces or, rather, arise from the viscous force during drainage of the fluid between two confining surfaces. In this paper we present our direct measurements of surface forces between mica sheets approaching in the ionic liquid [C2C1Im ] [NTf2] , exploring three orders of magnitude in approach velocity. Trajectories are systematically fitted by solving the equation of motion, allowing us to disentangle the viscous and equilibrium contributions. First, we find that the drainage obeys classical hydrodynamics with a negative slip boundary condition in the range of the structural force, implying that a nanometer -thick portion of the liquid in the vicinity of the solid surface is composed of ordered molecules that do not contribute to the flow. Second, we show that a long-range static force must indeed be invoked, in addition to the viscous force, in order to describe the data quantitatively. This equilibrium interaction decays exponentially and with decay length in agreement with the screening length reported for the same system in previous studies. In those studies the decay was simply checked to be independent of velocity and measured at a low approach rate, rather than explicitly taking account of viscous effects: we explain why this gives indistinguishable outcomes for the screening length by noting that the viscous force is linear to very good approximation over a wide range of distances.

Nanometer and molecular materials: the greatness of the very tiny; Materiales manometricos y moleculares: la grandeza de lo infimo

Energy Technology Data Exchange (ETDEWEB)

Rincon, Marina [Centro de Investigacion en Energia (CIE) de la UNAM, Temixco, Morelos (Mexico)

2010-07-01

Some of the materials have been present in our lives for many years, and now appear with unique or improved properties by the fact that they can be manufactured in the nanometer scale; that is, a million times smaller than a millimeter and with geometries that include the nanodots, the nanotubes, the nanowires, to mention a few of them. The most popular is the titanium dioxide (Titania), known by many as the white pigment in paints, sunscreens, cosmetics and others for their null toxicity, low cost and high stability. Strictly speaking, these features are really applicable to the micrometric material (which is a thousand times larger than the nanometer) and it is still to be proven toxicity and stability of the nanometer materials; but it is a fact that the nanometer titania is very popular in a multitude of applications that have to do with catalysis, sensors, and energy conversion and storing. We will also deal with conductive polymers, which are molecular conjugated materials. [Spanish] Algunos de los materiales han estado presentes en nuestras vidas por muchos anos y ahora aparecen con propiedades unicas o mejoradas por el hecho de que se pueden fabricar en la escala de los nanometros; esto es, un millon de veces mas pequenos que un milimetro y con geometrias que comprenden los nanopuntos, los nanotubos, los nanoalambres, por mencionar algunas. El mas popular es el dioxido de titanio (titania), conocido por muchos como el pigmento blanco de las pinturas, filtros solares, cosmeticos y demas, por su nula toxicidad, bajo costo y gran estabilidad. Estrictamente hablando, estas caracteristicas son realmente aplicables al material micrometrico (que es mil veces mas grande que el nanometrico) y todavia esta por probarse la toxicidad y estabilidad de los nanomateriales; pero es un hecho que la titania nanometrica es muy popular en un sinfin de aplicaciones que tienen que ver con catalisis, sensores, y conversion y almacenamiento de energia. Hablaremos tambien de

Test of methods for retrospective activity size distribution determination from filter samples

International Nuclear Information System (INIS)

Meisenberg, Oliver; Tschiersch, Jochen

2015-01-01

Determining the activity size distribution of radioactive aerosol particles requires sophisticated and heavy equipment, which makes measurements at large number of sites difficult and expensive. Therefore three methods for a retrospective determination of size distributions from aerosol filter samples in the laboratory were tested for their applicability. Extraction into a carrier liquid with subsequent nebulisation showed size distributions with a slight but correctable bias towards larger diameters compared with the original size distribution. Yields in the order of magnitude of 1% could be achieved. Sonication-assisted extraction into a carrier liquid caused a coagulation mode to appear in the size distribution. Sonication-assisted extraction into the air did not show acceptable results due to small yields. The method of extraction into a carrier liquid without sonication was applied to aerosol samples from Chernobyl in order to calculate inhalation dose coefficients for 137 Cs based on the individual size distribution. The effective dose coefficient is about half of that calculated with a default reference size distribution. - Highlights: • Activity size distributions can be recovered after aerosol sampling on filters. • Extraction into a carrier liquid and subsequent nebulisation is appropriate. • This facilitates the determination of activity size distributions for individuals. • Size distributions from this method can be used for individual dose coefficients. • Dose coefficients were calculated for the workers at the new Chernobyl shelter

Liquidity of Czech and Slovak commercial banks

OpenAIRE

Pavla Vodová

2012-01-01

As liquidity problems of some banks during global financial crisis re-emphasized, liquidity is very important for functioning of financial markets and the banking sector. The aim of this paper is therefore to evaluate comprehensively the liquidity positions of Czech and Slovak commercial banks via different liquidity ratios in the period of 2001–2010 and to find out whether the strategy for liquidity management differs by the size of the bank. We used unconsolidated balance sheet data over th...

Nanoconfined catalytic Ångström-size motors

Energy Technology Data Exchange (ETDEWEB)

Colberg, Peter H., E-mail: pcolberg@chem.utoronto.ca; Kapral, Raymond, E-mail: rkapral@chem.utoronto.ca [Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6 (Canada)

2015-11-14

Self-propelled chemically powered synthetic micron and nano-scale motors are being intensively studied because of the wide range of potential applications that exploit their directed motion. This paper considers even smaller Ångström-size synthetic motors. Such very small motors in bulk solution display effects arising from their self-propulsion. Recent experiments have shown that small-molecule catalysts and single enzyme molecules exhibit properties that have been attributed to their chemical activity. Molecular dynamics is used to investigate the properties of very small Ångström-size synthetic chemically powered sphere-dimer motors in a simple atomic-like solvent confined between walls separated by distances of tens of nanometers. Evidence for strong structural ordering of the motors between the walls, which reflects the finite size of solvent molecules and depends on solvent depletion forces, is provided. Dynamical properties, such as average motor velocity, orientational relaxation, and mean square displacement, are anisotropic and depend on the distance from the walls. This research provides information needed for potential applications that use molecular-scale motors in the complex confined geometries encountered in biology and the laboratory.

Nanoconfined catalytic Ångström-size motors

International Nuclear Information System (INIS)

Colberg, Peter H.; Kapral, Raymond

2015-01-01

Self-propelled chemically powered synthetic micron and nano-scale motors are being intensively studied because of the wide range of potential applications that exploit their directed motion. This paper considers even smaller Ångström-size synthetic motors. Such very small motors in bulk solution display effects arising from their self-propulsion. Recent experiments have shown that small-molecule catalysts and single enzyme molecules exhibit properties that have been attributed to their chemical activity. Molecular dynamics is used to investigate the properties of very small Ångström-size synthetic chemically powered sphere-dimer motors in a simple atomic-like solvent confined between walls separated by distances of tens of nanometers. Evidence for strong structural ordering of the motors between the walls, which reflects the finite size of solvent molecules and depends on solvent depletion forces, is provided. Dynamical properties, such as average motor velocity, orientational relaxation, and mean square displacement, are anisotropic and depend on the distance from the walls. This research provides information needed for potential applications that use molecular-scale motors in the complex confined geometries encountered in biology and the laboratory

Nanometer CMOS Sigma-Delta Modulators for Software Defined Radio

CERN Document Server

Morgado, Alonso; Rosa, José M

2012-01-01

This book presents innovative solutions for the implementation of Sigma-Delta Modulation (SDM) based Analog-to-Digital Conversion (ADC), required for the next generation of wireless hand-held terminals. These devices will be based on the so-called multistandard transceiver chipsets, integrated in nanometer CMOS technologies. One of the most challenging and critical parts in such transceivers is the analog-digital interface, because of the assorted signal bandwidths and dynamic ranges that can be required to handle the A/D conversion for several operation modes.   This book describes new adaptive and reconfigurable SDM ADC topologies, circuit strategies and synthesis methods, specially suited for multi-standard wireless telecom systems and future Software-defined-radios (SDRs) integrated in nanoscale CMOS. It is a practical book, going from basic concepts to the frontiers of SDM architectures and circuit implementations, which are explained in a didactical and systematic way. It gives a comprehensive overview...

A New Nonlinear Model of Body Resistance in Nanometer PD SOI MOSFETs

Directory of Open Access Journals (Sweden)

Arash Daghighi

2011-01-01

Full Text Available In this paper, a nonlinear model for the body resistance of a 45nm PD SOI MOSFET is developed. This model verified on the base of the small signal three-dimensional simulation results. In this paper by using the three-dimensional simulation of ISE-TCAD software, the indicating factors of body resistance in nanometer transistors and then are shown, using the surface potential model. A mathematical relation to calculat the body resistance incorporating device width and body potential was derived. Excellent agreement was obtained by comparing the model outputs and three-dimensional simulation results.

Liquidity of Czech and Slovak commercial banks

Directory of Open Access Journals (Sweden)

Pavla Vodová

2012-01-01

Full Text Available As liquidity problems of some banks during global financial crisis re-emphasized, liquidity is very important for functioning of financial markets and the banking sector. The aim of this paper is therefore to evaluate comprehensively the liquidity positions of Czech and Slovak commercial banks via different liquidity ratios in the period of 2001–2010 and to find out whether the strategy for liquidity management differs by the size of the bank. We used unconsolidated balance sheet data over the period from 2001 to 2010 which were obtained from annual reports of Czech and Slovak banks. The sample includes significant part of Czech and Slovak banking sector (not only by the number of banks, but also by their share on total banking assets. We have calculated five different liquidity ratios for each bank in the sample. The results showed that liquidity of Czech banks has declined during last ten years. On the contrary, liquidity of Slovak banks fluctuated only slightly during the period 2001–2008. Bank liquidity has fallen due to the financial crisis in both countries; the impact is worse for Slovak banks. Both Czech and Slovak banks have become less liquid also as a result of increase in lending activity. Czech and Slovak banks have the same strategies how to insure against liquidity crises: big banks rely on the interbank market or on a liquidity assistance of the Lender of Last Resort, small and medium sized banks hold buffer of liquid assets.

Effect of particle size on the glass transition.

Science.gov (United States)

Larsen, Ryan J; Zukoski, Charles F

2011-05-01

The glass transition temperature of a broad class of molecules is shown to depend on molecular size. This dependency results from the size dependence of the pair potential. A generalized equation of state is used to estimate how the volume fraction at the glass transition depends on the size of the molecule, for rigid molecule glass-formers. The model shows that at a given pressure and temperature there is a size-induced glass transition: For molecules larger than a critical size, the volume fraction required to support the effective pressure due to particle attractions is above that which characterizes the glassy state. This observation establishes the boundary between nanoparticles, which exist in liquid form only as dispersions in low molecular weight solvents and large molecules which form liquids that have viscosities below those characterized by the glassy state.

Online Stable Isotope Analysis of Dissolved Organic Carbon Size Classes Using Size Exclusion Chromatography Coupled to an Isotope Ratio Mass Spectrometer

Digital Repository Service at National Institute of Oceanography (India)

Malik, A.; Scheibe, A.; LokaBharathi, P.A.; Gleixner, G.

size classes by coupling high-performance liquid chromatography (HPLC) - size exclusion chromatography (SEC) to online isotope ratio mass spectrometry (IRMS). This represents a significant methodological contribution to DOC research. The interface...

Size-dependent nonlocal effects in plasmonic semiconductor particles

DEFF Research Database (Denmark)

Maack, Johan Rosenkrantz; Mortensen, N. Asger; Wubs, Martijn

2017-01-01

Localized surface plasmons (LSP) in semiconductor particles are expected to exhibit spatial nonlocal response effects as the geometry enters the nanometer scale. To investigate these nonlocal effects, we apply the hydrodynamic model to nanospheres of two different semiconductor materials: intrinsic...... InSb and n-doped GaAs. Our results show that the semiconductors indeed display nonlocal effects, and that these effects are even more pronounced than in metals. In a 150 nm InSb particle at 300 K, the LSP frequency is blueshifted 35%, which is orders of magnitude larger than the blueshift in a metal...... particle of the same size. This property, together with their tunability, makes semiconductors a promising platform for experiments in nonlocal effects. Copyright (C)EPLA, 2017...

Nanoparticle Analysis by Online Comprehensive Two-Dimensional Liquid Chromatography combining Hydrodynamic Chromatography and Size-Exclusion Chromatography with Intermediate Sample Transformation

Science.gov (United States)

2017-01-01

Polymeric nanoparticles have become indispensable in modern society with a wide array of applications ranging from waterborne coatings to drug-carrier-delivery systems. While a large range of techniques exist to determine a multitude of properties of these particles, relating physicochemical properties of the particle to the chemical structure of the intrinsic polymers is still challenging. A novel, highly orthogonal separation system based on comprehensive two-dimensional liquid chromatography (LC × LC) has been developed. The system combines hydrodynamic chromatography (HDC) in the first-dimension to separate the particles based on their size, with ultrahigh-performance size-exclusion chromatography (SEC) in the second dimension to separate the constituting polymer molecules according to their hydrodynamic radius for each of 80 to 100 separated fractions. A chip-based mixer is incorporated to transform the sample by dissolving the separated nanoparticles from the first-dimension online in tetrahydrofuran. The polymer bands are then focused using stationary-phase-assisted modulation to enhance sensitivity, and the water from the first-dimension eluent is largely eliminated to allow interaction-free SEC. Using the developed system, the combined two-dimensional distribution of the particle-size and the molecular-size of a mixture of various polystyrene (PS) and polyacrylate (PACR) nanoparticles has been obtained within 60 min. PMID:28745485

Cleanability evaluation of ceramic glazes with nanometer far-infrared materials using contact angle measurement.

Science.gov (United States)

Wang, Lijuan; Liang, Jinsheng; Di, Xingfu; Tang, Qingguo

2014-05-01

The cleanability of easy-to-clean ceramic glazes doped with nanometer far-infrared materials was compared with that of some high-quality household ceramic glazes from the market. The cleanability was evaluated by the contact angle measurement using a sessile drop method with a Dataphysics OCA-30 contact angle analyzer. The results showed that the difference of contact angles of water on the glazes before soiling and after cleaning could be used as a parameter for evaluating the cleanability of the glazes. The relationship between cleanability and surface properties, such as surface free energy and surface topography, was investigated. The surface free energy of the samples and their components were calculated using van Oss acid-base approach. By measuring advancing and receding contact angles, the contact angle hysteresis of the ceramic glazes due to the surface topography was investigated. It was shown that the cleanability of ceramic glazes containing nanometer far-infrared materials (NFIM) is better than that of household ceramic glazes from market, due to a higher ratio of electron-acceptor parameter to electron-donor parameter, which led to the effect of water hydration as well as better hydrophilic property and increased smoothness. The contact angle measurement not only accurately evaluates the cleanability of the ceramic glazes, but also has a contribution to the study of cleanability theory. Moreover, this method is simple, convenient and less sample-consumption.

Research on long-range grating interferometry with nanometer resolution

International Nuclear Information System (INIS)

Chu, Xingchun; Zhao, Shanghong; Lü, Haibao

2008-01-01

Grating interferometry that features long range and nanometer resolution is presented. The optical system was established based on a single long metrology grating. The large fringe multiplication was achieved by properly selecting two high-order diffraction beams to form a fringe pattern. The fringe pattern collected by a linear array was first tailored to a few multiples of fringes in order to suppress the effect of the energy leakage on phase-extracting precision when the fast Fourier transform (FFT) algorithm was used to calculate its phase. Thus, the phase-extracting precision of a tailored fringe pattern by FFT was greatly improved. Based on this, a novel subdividing method, which exploited the time-shift property of FFT, was developed to subdivide the fringe with large multiple and high accuracy. Numerical results show that the system resolution reaches 1 nm. The experimental results obtained against a capacitive sensor in the sub-mm range show that the measurement precision of the system is less than 10 nm. (technical design note)

Numerical simulation of the gas-liquid interaction of a liquid jet in supersonic crossflow

Science.gov (United States)

Li, Peibo; Wang, Zhenguo; Sun, Mingbo; Wang, Hongbo

2017-05-01

The gas-liquid interaction process of a liquid jet in supersonic crossflow with a Mach number of 1.94 was investigated numerically using the Eulerian-Lagrangian method. The KH (Kelvin-Helmholtz) breakup model was used to calculate the droplet stripping process, and the secondary breakup process was simulated by the competition of RT (Rayleigh-Taylor) breakup model and TAB (Taylor Analogy Breakup) model. A correction of drag coefficient was proposed by considering the compressible effects and the deformation of droplets. The location and velocity models of child droplets after breakup were improved according to droplet deformation. It was found that the calculated spray features, including spray penetration, droplet size distribution and droplet velocity profile agree reasonably well with the experiment. Numerical results revealed that the streamlines of air flow could intersect with the trajectory of droplets and are deflected towards the near-wall region after they enter into spray zone around the central plane. The analysis of gas-liquid relative velocity and droplet deformation suggested that the breakup of droplets mainly occurs around the front region of the spray where gathered a large number of droplets with different sizes. The liquid trailing phenomenon of jet spray which has been discovered by the previous experiment was successfully captured, and a reasonable explanation was given based on the analysis of gas-liquid interaction process.

Direct current dielectrophoretic manipulation of the ionic liquid droplets in water.

Science.gov (United States)

Zhao, Kai; Li, Dongqing

2018-07-13

The ionic liquids (ILs) as the environmentally benign solvents show great potentials in microemulsion carrier systems and have been widely used in the biochemical and pharmaceutical fields. In the work, the ionic liquid-in-water microemulsions were fabricated by using two kinds of hydrophobic ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate [Bmim][PF 6 ] and 1-Hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF 6 ] with Tween 20. The ionic liquid droplets in water experience the dielectrophoretic (DEP) forces induced by applying electrical field via a nano-orifice and a micron orifice on the opposite channel walls of a microchannel. The dielectrophoretic behaviors of the ionic liquid-in-water emulsion droplets were investigated under direct current (DC) electric field. The positive and negative DEP behaviors of the ionic liquid-in-water droplets varying with the electrical conductivity of the suspending medium were investigated and two kinds of the ionic liquid droplets of similar sizes were separated by their different DEP behaviors. In addition, the separation of the ionic liquid-in-water droplets by size was conducted. This paper, for the first time to our knowledge, presents the DC-DEP manipulation of the ionic liquid-in-water emulsion droplets by size and by type. This method provides a platform to manipulate the ionic liquid droplets individually. Copyright © 2018 Elsevier B.V. All rights reserved.

2D surface optical lattice formed by plasmon polaritons with application to nanometer-scale molecular deposition.

Science.gov (United States)

Yin, Yanning; Xu, Supeng; Li, Tao; Yin, Yaling; Xia, Yong; Yin, Jianping

2017-08-10

Surface plasmon polaritons, due to their tight spatial confinement and high local intensity, hold great promises in nanofabrication which is beyond the diffraction limit of conventional lithography. Here, we demonstrate theoretically the 2D surface optical lattices based on the surface plasmon polariton interference field, and the potential application to nanometer-scale molecular deposition. We present the different topologies of lattices generated by simple configurations on the substrate. By explicit theoretical derivations, we explain their formation and characteristics including field distribution, periodicity and phase dependence. We conclude that the topologies can not only possess a high stability, but also be dynamically manipulated via changing the polarization of the excitation laser. Nanometer-scale molecular deposition is simulated with these 2D lattices and discussed for improving the deposition resolution. The periodic lattice point with a width resolution of 33.2 nm can be obtained when the fullerene molecular beam is well-collimated. Our study can offer a superior alternative method to fabricate the spatially complicated 2D nanostructures, with the deposition array pitch serving as a reference standard for accurate and traceable metrology of the SI length standard.

Isolation, characterization, and stability of discretely-sized nanolipoprotein particles assembled with apolipophorin-III.

Directory of Open Access Journals (Sweden)

Nicholas O Fischer

Full Text Available BACKGROUND: Nanolipoprotein particles (NLPs are discoidal, nanometer-sized particles comprised of self-assembled phospholipid membranes and apolipoproteins. NLPs assembled with human apolipoproteins have been used for myriad biotechnology applications, including membrane protein solubilization, drug delivery, and diagnostic imaging. To expand the repertoire of lipoproteins for these applications, insect apolipophorin-III (apoLp-III was evaluated for the ability to form discretely-sized, homogeneous, and stable NLPs. METHODOLOGY: Four NLP populations distinct with regards to particle diameters (ranging in size from 10 nm to >25 nm and lipid-to-apoLp-III ratios were readily isolated to high purity by size exclusion chromatography. Remodeling of the purified NLP species over time at 4 degrees C was monitored by native gel electrophoresis, size exclusion chromatography, and atomic force microscopy. Purified 20 nm NLPs displayed no remodeling and remained stable for over 1 year. Purified NLPs with 10 nm and 15 nm diameters ultimately remodeled into 20 nm NLPs over a period of months. Intra-particle chemical cross-linking of apoLp-III stabilized NLPs of all sizes. CONCLUSIONS: ApoLp-III-based NLPs can be readily prepared, purified, characterized, and stabilized, suggesting their utility for biotechnological applications.

Method for sizing hollow microspheres

Science.gov (United States)

Farnum, E.H.; Fries, R.J.

1975-10-29

Hollow Microspheres may be effectively sized by placing them beneath a screen stack completely immersed in an ultrasonic bath containing a liquid having a density at which the microspheres float and ultrasonically agitating the bath.

Dual-mode nonlinear instability analysis of a confined planar liquid sheet sandwiched between two gas streams of unequal velocities and prediction of droplet size and velocity distribution using maximum entropy formulation

Science.gov (United States)

Dasgupta, Debayan; Nath, Sujit; Bhanja, Dipankar

2018-04-01

Twin fluid atomizers utilize the kinetic energy of high speed gases to disintegrate a liquid sheet into fine uniform droplets. Quite often, the gas streams are injected at unequal velocities to enhance the aerodynamic interaction between the liquid sheet and surrounding atmosphere. In order to improve the mixing characteristics, practical atomizers confine the gas flows within ducts. Though the liquid sheet coming out of an injector is usually annular in shape, it can be considered to be planar as the mean radius of curvature is much larger than the sheet thickness. There are numerous studies on breakup of the planar liquid sheet, but none of them considered the simultaneous effects of confinement and unequal gas velocities on the spray characteristics. The present study performs a nonlinear temporal analysis of instabilities in the planar liquid sheet, produced by two co-flowing gas streams moving with unequal velocities within two solid walls. The results show that the para-sinuous mode dominates the breakup process at all flow conditions over the para-varicose mode of breakup. The sheet pattern is strongly influenced by gas velocities, particularly for the para-varicose mode. Spray characteristics are influenced by both gas velocity and proximity to the confining wall, but the former has a much more pronounced effect on droplet size. An increase in the difference between gas velocities at two interfaces drastically shifts the droplet size distribution toward finer droplets. Moreover, asymmetry in gas phase velocities affects the droplet velocity distribution more, only at low liquid Weber numbers for the input conditions chosen in the present study.

Fabrication of atomic-scale gold junctions by electrochemical plating using a common medical liquid

Science.gov (United States)

Umeno, A.; Hirakawa, K.

2005-04-01

Fabrication of nanometer-separated gold junctions has been performed using "iodine tincture," a medical liquid known as a disinfectant, as an etching/deposition electrolyte. In the gold-dissolved iodine tincture, gold electrodes were grown or eroded slowly enough to form quantum point contacts in an atomic scale. The resistance evolution during the electrochemical deposition showed plateaus at integer multiples of the resistance quantum, (2e2/h)-1, at room temperature (e: the elementary charge, h: the Planck constant). Iodine tincture is a commercially available common material, which makes the fabrication process to be simple and cost effective. Moreover, in contrast to the conventional electrochemical approaches, this method is free from highly toxic cyanide compounds or extraordinarily strong acids.

Simulation Of Gas Focused Liquid Jets

OpenAIRE

Zahoor, Rizwan

2018-01-01

The main aim of dissertation is to develop an experimentally verified computational fluid dynamic (CFD) model of micron-sized liquid jet, produced by an injection molded Gas Dynamic Virtual Nozzle (GDVN). In these nozzles, liquid jets are efficiently orientedly transporting mass and momentum. They are produced by intelligently projecting hydrodynamic focusing effect from a high-speed stream of a co-flowing lower density and lower viscosity gas on a stream of liquid from a feeding capillary. L...

Ceramic membrane development in NGK

Energy Technology Data Exchange (ETDEWEB)

Araki, Kiyoshi; Sakai, Hitoshi, E-mail: kinsakai@ngk.co.jp [Corporate R and D, NGK Insulators, Ltd., Nagoya 467-8530 (Japan)

2011-05-15

NGK Insulators, Ltd. was established in 1919 to manufacture the electric porcelain insulators for power transmission lines. Since then, our business has grown as one of the world-leading ceramics manufacturing companies and currently supply with the various environmentally-benign ceramic products to worldwide. In this paper, ceramic membrane development in NGK is described in detail. We have been selling ceramic microfiltration (MF) membranes and ultra-filtration (UF) membranes for many years to be used for solid/liquid separation in various fields such as pharmaceutical, chemical, food and semiconductor industries. In Corporate R and D, new ceramic membranes with sub-nanometer sized pores, which are fabricated on top of the membrane filters as support, are under development for gas and liquid/liquid separation processes.

Ceramic membrane development in NGK

Science.gov (United States)

Araki, Kiyoshi; Sakai, Hitoshi

2011-05-01

NGK Insulators, Ltd. was established in 1919 to manufacture the electric porcelain insulators for power transmission lines. Since then, our business has grown as one of the world-leading ceramics manufacturing companies and currently supply with the various environmentally-benign ceramic products to worldwide. In this paper, ceramic membrane development in NGK is described in detail. We have been selling ceramic microfiltration (MF) membranes and ultra-filtration (UF) membranes for many years to be used for solid/liquid separation in various fields such as pharmaceutical, chemical, food and semiconductor industries. In Corporate R&D, new ceramic membranes with sub-nanometer sized pores, which are fabricated on top of the membrane filters as support, are under development for gas and liquid/liquid separation processes.

Granule size control and targeting in pulsed spray fluid bed granulation.

Science.gov (United States)

Ehlers, Henrik; Liu, Anchang; Räikkönen, Heikki; Hatara, Juha; Antikainen, Osmo; Airaksinen, Sari; Heinämäki, Jyrki; Lou, Honxiang; Yliruusi, Jouko

2009-07-30

The primary aim of the study was to investigate the effects of pulsed liquid feed on granule size. The secondary aim was to increase knowledge of this technique in granule size targeting. Pulsed liquid feed refers to the pump changing between on- and off-positions in sequences, called duty cycles. One duty cycle consists of one on- and off-period. The study was performed with a laboratory-scale top-spray fluid bed granulator with duty cycle length and atomization pressure as studied variables. The liquid feed rate, amount and inlet air temperature were constant. The granules were small, indicating that the powder has only undergone ordered mixing, nucleation and early growth. The effect of atomizing pressure on granule size depends on inlet air relative humidity, with premature binder evaporation as a reason. The duty cycle length was of critical importance to the end product attributes, by defining the extent of intermittent drying and rewetting. By varying only the duty cycle length, it was possible to control granule nucleation and growth, with a wider granule size target range in increased relative humidity. The present study confirms that pulsed liquid feed in fluid bed granulation is a useful tool in end product particle size targeting.

Phase- and size-controllable synthesis of hexagonal upconversion rare-earth fluoride nanocrystals through an oleic acid/ionic liquid two-phase system.

Science.gov (United States)

He, Meng; Huang, Peng; Zhang, Chunlei; Ma, Jiebing; He, Rong; Cui, Daxiang

2012-05-07

Herein, we introduce a facile, user- and environmentally friendly (n-octanol-induced) oleic acid (OA)/ionic liquid (IL) two-phase system for the phase- and size-controllable synthesis of water-soluble hexagonal rare earth (RE = La, Gd, and Y) fluoride nanocrystals with uniform morphologies (mainly spheres and elongated particles) and small sizes (size are discussed in detail. More importantly, the mechanism of the (n-octanol-induced) OA/IL two-phase system, the formation of the RE fluoride nanocrystals, and the distinctive size- and morphology-controlling capacity of the system are presented. BmimPF(6) is versatile in term of crystal-phase manipulation, size and shape maintenance, and providing water solubility in a one-step reaction. The luminescent properties of Er(3+)-, Ho(3+)-, and Tm(3+)-doped LaF(3), NaGdF(4), and NaYF(4) nanocrystals were also studied. It is worth noting that the as-prepared products can be directly dispersed in water due to the hydrophilic property of Bmim(+) (cationic part of the IL) as a capping agent. This advantageous feature has made the IL-capped products favorable in facile surface modifications, such as the classic Stober method. Finally, the cytotoxicity evaluation of NaYF(4):Yb,Er nanocrystals before and after silica coating was conducted for further biological applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Accounting for nanometer-thick adventitious carbon contamination in X-ray absorption spectra of carbon-based materials.

Science.gov (United States)

Mangolini, Filippo; McClimon, J Brandon; Rose, Franck; Carpick, Robert W

2014-12-16

Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is a powerful technique for characterizing the composition and bonding state of nanoscale materials and the top few nanometers of bulk and thin film specimens. When coupled with imaging methods like photoemission electron microscopy, it enables chemical imaging of materials with nanometer-scale lateral spatial resolution. However, analysis of NEXAFS spectra is often performed under the assumption of structural and compositional homogeneity within the nanometer-scale depth probed by this technique. This assumption can introduce large errors when analyzing the vast majority of solid surfaces due to the presence of complex surface and near-surface structures such as oxides and contamination layers. An analytical methodology is presented for removing the contribution of these nanoscale overlayers from NEXAFS spectra of two-layered systems to provide a corrected photoabsorption spectrum of the substrate. This method relies on the subtraction of the NEXAFS spectrum of the overlayer adsorbed on a reference surface from the spectrum of the two-layer system under investigation, where the thickness of the overlayer is independently determined by X-ray photoelectron spectroscopy (XPS). This approach is applied to NEXAFS data acquired for one of the most challenging cases: air-exposed hard carbon-based materials with adventitious carbon contamination from ambient exposure. The contribution of the adventitious carbon was removed from the as-acquired spectra of ultrananocrystalline diamond (UNCD) and hydrogenated amorphous carbon (a-C:H) to determine the intrinsic photoabsorption NEXAFS spectra of these materials. The method alters the calculated fraction of sp(2)-hybridized carbon from 5 to 20% and reveals that the adventitious contamination can be described as a layer containing carbon and oxygen ([O]/[C] = 0.11 ± 0.02) with a thickness of 0.6 ± 0.2 nm and a fraction of sp(2)-bonded carbon of 0.19 ± 0.03. This

Capillary waves of compressible fluids

International Nuclear Information System (INIS)

Falk, Kerstin; Mecke, Klaus

2011-01-01

The interplay of thermal noise and molecular forces is responsible for surprising features of liquids on sub-micrometer lengths-in particular at interfaces. Not only does the surface tension depend on the size of an applied distortion and nanoscopic thin liquid films dewet faster than would be expected from hydrodynamics, but also the dispersion relation of capillary waves differ at the nanoscale from the familiar macroscopic behavior. Starting with the stochastic Navier-Stokes equation we study the coupling of capillary waves to acoustic surface waves which is possible in compressible fluids. We find propagating 'acoustic-capillary waves' at nanometer wavelengths where in incompressible fluids capillary waves are overdamped.

Electrical control of Faraday rotation at a liquid-liquid interface.

Science.gov (United States)

Marinescu, Monica; Kornyshev, Alexei A; Flatté, Michael E

2015-01-01

A theory is developed for the Faraday rotation of light from a monolayer of charged magnetic nanoparticles at an electrified liquid-liquid interface. The polarization fields of neighboring nanoparticles enhance the Faraday rotation. At such interfaces, and for realistic sizes and charges of nanoparticles, their adsorption-desorption can be controlled with a voltage variationFaraday rotation. A calculation based on the Maxwell-Garnett theory predicts that the corresponding redistribution of 40 nm nanoparticles of yttrium iron garnet can switch a cavity with a quality factor larger than 10(4) for light of wavelength 500 nm at normal incidence.

NANOMETER PRECISION IN LARGE SURFACE PROFILOMETRY

International Nuclear Information System (INIS)

TAKACS, P.Z.

1999-01-01

The Long Trace Profiler (LTP) is in use at many synchrotron radiation (SR) laboratories throughout the world and by a number of manufacturers who specialize in fabricating grazing incidence mirrors for SR and x-ray telescope applications. Recent improvements in the design and operation of the LTP system have reduced the statistical error in slope profile measurement to the 1 standard deviation level of 0.3 microradian for 0.5 meter long mirrors. This corresponds to a height error on the order of 10-20 nanometers. This level of performance allows one to measure with confidence the absolute shape of large cylindrical aspheres and spheres that have kilometer radii of curvature in the axial direction. The LTP is versatile enough to make measurements of a mirror in the face up, sideways, and face down configurations. We will illustrate the versatility of the current version of the instrument, the LTP II, and present results from two new versions of the instrument: the in situ LTP (ISLTP) and the Vertical Scan LTP (VSLTP). Both of them are based on the penta prism LTP (ppLTP) principle that utilizes a stationary optical head and moving penta prism. The ISLTP is designed to measure the distortion of high heat load mirrors during actual operation in SR beam lines. The VSLTP is designed to measure the complete 3-dimensional shape of x-ray telescope cylinder mirrors and mandrels in a vertical configuration. Scans are done both in the axial direction and in the azimuthal direction

Study on Droplet Size and Velocity Distributions of a Pressure Swirl Atomizer Based on the Maximum Entropy Formalism

Directory of Open Access Journals (Sweden)

Kai Yan

2015-01-01

Full Text Available A predictive model for droplet size and velocity distributions of a pressure swirl atomizer has been proposed based on the maximum entropy formalism (MEF. The constraint conditions of the MEF model include the conservation laws of mass, momentum, and energy. The effects of liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio on the droplet size and velocity distributions of a pressure swirl atomizer are investigated. Results show that model based on maximum entropy formalism works well to predict droplet size and velocity distributions under different spray conditions. Liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio have different effects on droplet size and velocity distributions of a pressure swirl atomizer.

Energy dependent track structure parametrizations for protons and carbon ions based on nano-metric simulations

International Nuclear Information System (INIS)

Frauke, A.; Wilkens, J.J.; Villagrasa, C.; Rabus, H.

2015-01-01

The BioQuaRT project within the European Metrology Research Programme aims at correlating ion track structure characteristics with the biological effects of radiation and develops measurement and simulation techniques for determining ion track structure on different length scales from about 2 nm to about 10 μm. Within this framework, we investigate methods to translate track-structure quantities derived on a nanometer scale to macroscopic dimensions. Input data sets were generated by simulations of ion tracks of protons and carbon ions in liquid water using the Geant-4 Monte Carlo tool-kit with the Geant-4-DNA processes. Based on the energy transfer points - recorded with nanometer resolution - we investigated parametrizations of overall properties of ion track structure. Three different track structure parametrizations have been developed using the distances to the 10 next neighbouring ionizations, the radial energy distribution and ionisation cluster size distributions. These parametrizations of nanometer-scale track structure build a basis for deriving biologically relevant mean values which are essential in the clinical situation where each voxel is exposed to a mixed radiation field. (authors)

Honeycomb-like thin films of polystyrene-block-poly(2-vinylpyridine) embedded with gold or silver nanoparticles formed at the planer liquid/liquid interface.

Science.gov (United States)

Wang, Di; Ma, Huihui; Chu, Chunxiao; Hao, Jingcheng; Liu, Hong-Guo

2013-07-15

Composite thin films of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) decorated with Au or Ag nanoclusters and nanoparticles were fabricated at the interfaces of chloroform solution of PS-b-P2VP and aqueous solutions of HAuCl4 or AgNO3. Transmission electron microscopy (TEM) investigations indicated that large area of a single-layer honeycomb structure was formed, which is composed of polygons (most of them are hexagons) whose walls look like spindles with the length of several hundreds of nanometers. Large amount of Au or Ag nanoparticles are embedded in the walls and the undersides of the honeycomb structures. The formation of these novel composite structures was attributed to the adsorption of block copolymer molecules and inorganic species of AuCl4(-) and Ag(+) ions at the liquid-liquid interface, the combination of the polymer molecules and the inorganic ions, and the self-assembly of the composite molecules. After UV-light irradiation and KBH4 aqueous solution treatment, the inorganic species were reduced completely, as confirmed by UV-vis spectra and X-ray photoelectron spectra. These composite films exhibited high catalytic activities for the reduction of 4-nitrophenol (4-NP) by KBH4 in aqueous solutions. Copyright © 2013 Elsevier Inc. All rights reserved.

Numerical investigation on liquid sheets interaction characteristics of liquid-liquid coaxial swirling jets in bipropellant thruster

International Nuclear Information System (INIS)

Ding, Jia-Wei; Li, Guo-Xiu; Yu, Yu-Song

2016-01-01

Highlights: • A LES-VOF model is conducted to simulate atomization of coaxial swirling jets. • Structure and flow field of coaxial swirling jets are investigated. • Merging process occurs at the nozzle exit and generates additional perturbation. • The Rayleigh mode instability dominates the breakup of ligaments. - Abstract: Spray atomization process of a liquid-liquid coaxial swirl injector in bipropellant thruster has been investigated using volume of fluid (VOF) method coupled with large eddy simulation methodology. With fine grid resolution, detailed flow field of interacted liquid sheet has been captured and analyzed. For coaxial swirling jet, static pressure drop in the region between the liquid sheets makes two liquid sheets to approach each other and merge. A strong pressure, velocity and turbulent fluctuations are calculated near the contact position of two coaxial jets. Simulation results indicate that additional perturbations are generated due to strong radial and axial shear effects between coaxial jets. Observation of droplet formation process reveals that the Rayleigh mode instability dominates the breakup of the ligament. Droplet diameter and distribution have been investigated quantitatively. The mean diameter of the coaxial jets is between that of the inner and the outer jets. Compared with the individual swirling jets, wider size distributions of droplets are produced in the coaxial jets.

Nanoparticles in liquid crystals, and liquid crystals in nanoparticles

Science.gov (United States)

de Pablo, Juan

2015-03-01

Liquid crystals are remarkably sensitive to interfacial interactions. Small perturbations at a liquid crystal interface, for example, can be propagated over relatively long length scales, thereby providing the basis for a wide range of applications that rely on amplification of molecular events into macroscopic observables. Our recent research efforts have focused on the reverse phenomenon; that is, we have sought to manipulate the interfacial assembly of nanoparticles or the organization of surface active molecules by controlling the structure of a liquid crystal. This presentation will consist of a review of the basic principles that are responsible for liquid crystal-mediated interactions, followed by demonstrations of those principles in the context of two types of systems. In the first, a liquid crystal is used to direct the assembly of nanoparticles; through a combination of molecular and continuum models, it is found that minute changes in interfacial energy and particle size lead to liquid-crystal induced attractions that can span multiple orders of magnitude. Theoretical predictions are confirmed by experimental observations, which also suggest that LC-mediated assembly provides an effective means for fabrication of plasmonic devices. In the second type of system, the structure of a liquid crystal is controlled by confinement in submicron droplets. The morphology of the liquid crystal in a drop depends on a delicate balance between bulk and interfacial contributions to the free energy; that balance can be easily perturbed by adsorption of analytes or nanoparticles at the interface, thereby providing the basis for development of hierarchical assembly of responsive, anisotropic materials. Theoretical predictions also indicate that the three-dimensional order of a liquid crystal can be projected onto a two-dimensional interface, and give rise to novel nanostructures that are not found in simple isotropic fluids.

Liquid foam templating - A route to tailor-made polymer foams.

Science.gov (United States)

Andrieux, Sébastien; Quell, Aggeliki; Stubenrauch, Cosima; Drenckhan, Wiebke

2018-06-01

Solid foams with pore sizes between a few micrometres and a few millimetres are heavily exploited in a wide range of established and emerging applications. While the optimisation of foam applications requires a fine control over their structural properties (pore size distribution, pore opening, foam density, …), the great complexity of most foaming processes still defies a sound scientific understanding and therefore explicit control and prediction of these parameters. We therefore need to improve our understanding of existing processes and also develop new fabrication routes which we understand and which we can exploit to tailor-make new porous materials. One of these new routes is liquid templating in general and liquid foam templating in particular, to which this review article is dedicated. While all solid foams are generated from an initially liquid(-like) state, the particular notion of liquid foam templating implies the specific condition that the liquid foam has time to find its "equilibrium structure" before it is solidified. In other words, the characteristic time scales of the liquid foam's stability and its solidification are well separated, allowing to build on the vast know-how on liquid foams established over the last 20 years. The dispersed phase of the liquid foam determines the final pore size and pore size distribution, while the continuous phase contains the precursors of the desired porous scaffold. We review here the three key challenges which need to be addressed by this approach: (1) the control of the structure of the liquid template, (2) the matching of the time scales between the stability of the liquid template and solidification, and (3) the preservation of the structure of the template throughout the process. Focusing on the field of polymer foams, this review gives an overview of recent research on the properties of liquid foam templates and summarises a key set of studies in the emerging field of liquid foam templating. It

Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT

DEFF Research Database (Denmark)

Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios

2004-01-01

concentration coexistence curves at fixed pressure and temperature. The algorithms automatically trace the entire liquid-liquid coexistence curves in steps by adjusting the step size, generating initial estimates, and subsequently solving the phase-equilibrium problem by a second-order method. The algorithms...... are used for investigating the correlative and predictive capabilities of the thermodynamic model PC-SAFT. The investigation shows that the model correlates well experimental LLE data for binary as well as ternary systems but further predicts the behavior of the ternary systems with reasonably good...

The Effects of Liquidity Regulation on Bank Assets and Liabilities

OpenAIRE

Patty Duijm; Peter Wierts

2014-01-01

Under Basel III rules, banks become subject to a liquidity coverage ratio (LCR) from 2015 onwards, to promote short-term resilience. We investigate the effects of such liquidity regulation on bank liquid assets and liabilities. Results indicate co-integration of liquid assets and liabilities, to maintain a minimum short-term liquidity buffer. Still, microprudential regulation has not prevented an aggregate liquidity cycle characterised by a pro-cyclical pattern in the size of balance sheets a...

COMPANY SIZE, TRADING ACTIVITY AND LIQUIDITY AS A DETERMINANTS OF CROSS-SECTIONAL MOMENTUM TRADING STRATEGY ON RUSSIAN STOCK MARKET

Directory of Open Access Journals (Sweden)

Teplova T. V.

2014-06-01

Full Text Available Momentum-effect has many interpretations in the practice of investing and in understanding of anomalies in asset prices. We consider a Cross-Sectional momentum effects and the corresponding two medium-term (3 months or more trading strategies that are different from the trend following rules for individual assets. We tested four hypothesis deals with cross-sectional momentum effect on the Russian stock market and the possibility of building a self-financing (long-short trading strategy at three time horizon (stock market growth from 2004 until mid 2008, financial crisis and post-crisis periods. It is shown that for the Russian market cross-sectional momentum strategy with partly rebalanced portfolio maximizing portfolio return (134 stocks listed from 2004 to 2014 in the few Russian stock exchanges should be based on the three-month formation period and three-month holding period periods (3/1/3. We have identified elements of profit-maximizing momentum strategy: three time windows and determinants of assets. Monthly average return of arbitrage strategy is estimated at 1.5 % for 134 common shares. Implementation of the strategy for the post-crisis period does not allow to maximize profit. For 6-month and more investment windows it gets the advantage of reverse strategy (opening long positions in stocks with low investment results and short position for assets with high relative returns. Fundamental parameters of the issuer (size of companies like market capitalization and two measures of liquidity (trading activity and transaction costs like bid-ask spread are significant to maximize portfolio performance (we prove the growth of monthly average return ranging from 1.5 to 2.5 %. We find that size and liquidity control momentum strategy can earn positive profits in Russian stock market, larger than naïve momentum.

Liquid metal flow measurement by neutron radiography

International Nuclear Information System (INIS)

Takenaka, N.; Ono, A.; Matsubayashi, M.; Tsuruno, A.

1996-01-01

Visualization of a liquid metal flow and image processing methods to measure the vector field are carried out by real-time neutron radiography. The JRR-3M real-time thermal neutron radiography facility in the Japan Atomic Energy Research Institute was used. Lead-bismuth eutectic was used as a working fluid. Particles made from a gold-cadmium intermetallic compound (AuCd 3 ) were used as the tracer for the visualization. The flow vector field was obtained by image processing methods. It was shown that the liquid metal flow vector field was obtainable by real-time neutron radiography when the attenuation of neutron rays due to the liquid metal was less than l/e and the particle size of the tracer was larger than one image element size digitized for the image processing. (orig.)

Nanoarchitecture Control Enabled by Ionic Liquids

Science.gov (United States)

Murdoch, Heather A.; Limmer, Krista R.; Labukas, Joseph P.

2017-04-01

Ionic liquids have many advantages over traditional aqueous electrosynthesis for fabrication of functional nanoarchitectures, including enabling the integration of nanoparticles into traditional coatings, superhydrophobicity, nanofoams, and other hierarchical structures. Shape and size control through ionic liquid selection and processing conditions can synthesize nanoparticles and nanoarchitectures without the use of capping agents, surfactants, or templates that are often deleterious to the functionality of the resultant system. Here we give a brief overview of some recent and interesting applications of ionic liquids to the synthesis of nanoparticles and nanoarchitectures.

Carbon nanotube transistors scaled to a 40-nanometer footprint.

Science.gov (United States)

Cao, Qing; Tersoff, Jerry; Farmer, Damon B; Zhu, Yu; Han, Shu-Jen

2017-06-30

The International Technology Roadmap for Semiconductors challenges the device research community to reduce the transistor footprint containing all components to 40 nanometers within the next decade. We report on a p-channel transistor scaled to such an extremely small dimension. Built on one semiconducting carbon nanotube, it occupies less than half the space of leading silicon technologies, while delivering a significantly higher pitch-normalized current density-above 0.9 milliampere per micrometer at a low supply voltage of 0.5 volts with a subthreshold swing of 85 millivolts per decade. Furthermore, we show transistors with the same small footprint built on actual high-density arrays of such nanotubes that deliver higher current than that of the best-competing silicon devices under the same overdrive, without any normalization. We achieve this using low-resistance end-bonded contacts, a high-purity semiconducting carbon nanotube source, and self-assembly to pack nanotubes into full surface-coverage aligned arrays. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Cloud Droplet Size and Liquid Water Path Retrievals From Zenith Radiance Measurements: Examples From the Atmospheric Radiation Measurement Program and the Aerosol Robotic Network

Science.gov (United States)

Chiu, J. C.; Marshak, A.; Huang, C.-H.; Varnai, T.; Hogan, R. J.; Giles, D. M.; Holben, B. N.; Knyazikhin, Y.; O'Connor, E. J.; Wiscombe, W. J.

2012-01-01

The ground-based Atmospheric Radiation Measurement Program (ARM) and NASA Aerosol Robotic Network (AERONET) routinely monitor clouds using zenith radiances at visible and near-infrared wavelengths. Using the transmittance calculated from such measurements, we have developed a new retrieval method for cloud effective droplet size and conducted extensive tests for non-precipitating liquid water clouds. The underlying principle is to combine a water-absorbing wavelength (i.e. 1640 nm) with a nonwater-absorbing wavelength for acquiring information on cloud droplet size and optical depth. For simulated stratocumulus clouds with liquid water path less than 300 g/sq m and horizontal resolution of 201m, the retrieval method underestimates the mean effective radius by 0.8 m, with a root-mean-squared error of 1.7 m and a relative deviation of 13 %. For actual observations with a liquid water path less than 450 gm.2 at the ARM Oklahoma site during 2007-2008, our 1.5 min-averaged retrievals are generally larger by around 1 m than those from combined ground-based cloud radar and microwave radiometer at a 5min temporal resolution. We also compared our retrievals to those from combined shortwave flux and microwave observations for relatively homogeneous clouds, showing that the bias between these two retrieval sets is negligible, but the error of 2.6 m and the relative deviation of 22% are larger than those found in our simulation case. Finally, the transmittance-based cloud effective droplet radii agree to better than 11% with satellite observations and have a negative bias of 1 m. Overall, the retrieval method provides reasonable cloud effective radius estimates, which can enhance the cloud products of both ARM and AERONET.

Preparation of nano-sized {alpha}-Al{sub 2}O{sub 3} from oil shale ash

Energy Technology Data Exchange (ETDEWEB)

An, Baichao; Wang, Wenying; Ji, Guijuan; Gan, Shucai; Gao, Guimei; Xu, Jijing; Li, Guanghuan [College of Chemistry, Jilin University, Changchun 130026 (China)

2010-01-15

Oil shale ash (OSA), the residue of oil shale semi-coke roasting, was used as a raw material to synthesize nano-sized {alpha}-Al{sub 2}O{sub 3}. Ultrasonic oscillation pretreatment followed by azeotropic distillation was employed for reducing the particle size of {alpha}-Al{sub 2}O{sub 3}. The structural characterization at molecular and nanometer scales was performed using X-ray diffraction (XRD), transmission electron microscopy (TEM), respectively. The interaction between alumina and n-butanol was characterized by Fourier transform infrared spectroscopy (FT-IR). The results revealed that the crystalline phase of alumina nanoparticles was regular and the well dispersed alumina nanoparticles had a diameter of 50-80 nm. In addition, the significant factors including injection rate of carbon oxide (CO{sub 2}), ultrasonic oscillations, azeotropic distillation and surfactant were investigated with respect to their effects on the size of the alumina particles. (author)

Spinel Li{sub 2}CoTi{sub 3}O{sub 8} nanometer obtained for application as pigment; Espinela Li{sub 2}CoTi{sub 3}O{sub 8} nanometrica obtenida para aplicacion como pigmento

Energy Technology Data Exchange (ETDEWEB)

Costa de Camara, M. S.; Alves Pimentel, L.; Longo, E.; Nobrega Azevedo, L. da; Araujo Melo, D. M. de

2016-05-01

Pigments are used in ceramics, cosmetics, inks, and other applications widely materials. To this must be single and easily reproducible. Moreover, the pigments obtained in the nanoscale are more stable, reproducible and highlight color in small amounts compared with those obtained in micrometer scale. The mixed oxides with spinel structures AB{sub 2}O{sub 4} have important applications, including: pigments, refractories, catalytic and electronic ceramics. In this context, the aim of this work was the preparation of powder Li{sub 2}CoTi{sub 3}O{sub 8} spinel phase with nanometer particle size of the polymeric precursor method (Pechini) and characterization by means of thermal analysis (TG/DTA) X-ray diffraction (XRD), refined by the Rietveld method, BET, transmission electron microscopy (TEM), Raman and colorimetric coordinates. The pigment was obtained by heat treatment of 400 degree centigrade to 1000 degree centigrade after pyrolysis at 300 degree centigrade/1 h for removing the organic material. Li{sub 2}CoTi{sub 3}O{sub 8} desired spinel phase was obtained from 500 degree centigrade, and presenting stability nanometer to about 1.300 degree centigrade. Spinel green phase introduced at temperatures in the range of 400 degree centigrade and 500 degree centigrade, and 600 degree centigrade at temperatures between blue and 1000 degree centigrade. (Author)

Helium Ion Microscope: A New Tool for Sub-nanometer Imaging of Soft Materials

Science.gov (United States)

Shutthanandan, V.; Arey, B.; Smallwood, C. R.; Evans, J. E.

2017-12-01

High-resolution inspection of surface details is needed in many biological and environmental researches to understand the Soil organic material (SOM)-mineral interactions along with identifying microbial communities and their interactions. SOM shares many imaging characteristics with biological samples and getting true surface details from these materials are challenging since they consist of low atomic number materials. FE-SEM imaging is the main imagining technique used to image these materials in the past. These SEM images often show loss of resolution and increase noise due to beam damage and charging issues. Newly developed Helium Ion Microscope (HIM), on the other hand can overcome these difficulties and give very fine details. HIM is very similar to scanning electron microscopy (SEM) but instead of using electrons as a probe beam, HIM uses helium ions with energy ranges from 5 to 40 keV. HIM offers a series of advantages compared to SEM such as nanometer and sub-nanometer image resolutions (about 0.35 nm), detailed surface topography, high surface sensitivity, low Z material imaging (especially for polymers and biological samples), high image contrast, and large depth of field. In addition, HIM also has the ability to image insulating materials without any conductive coatings so that surface details are not modified. In this presentation, several scientific applications across biology and geochemistry will be presented to highlight the effectiveness of this powerful microscope. Acknowledgements: Research was performed using the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at PNNL. Work was supported by DOE-BER Mesoscale to Molecules Bioimaging Project FWP# 66382.

Visualization of residual organic liquid trapped in aquifers

International Nuclear Information System (INIS)

Conrad, S.H.; Wilson, J.L.; Mason, W.R.; Peplinski, W.J.

1992-01-01

Organic liquids that are essentially immiscible with water migrate through the subsurface under the influence of capillary, viscous, and buoyancy forces. These liquids originate from the improper disposal of hazardous wastes, and the spills and leaks of petroleum hydrocarbons and solvents. The flow visualization experiments described in this study examined the migration of organic liquids through the saturated zone of aquifers, with a primary focus on the behavior of the residual organic liquid saturation, referring to that portion of the organic liquid that is trapped by capillary forces. Etched glass micromodels were used to visually observe dynamic multiphase displacement processes in pore networks. The resulting fluid distributions were photographed. Pore and blob casts were produced by a technique in which an organic liquid was solidified in place within a sand column at the conclusion of a displacement. The columns were sectioned and examined under optical and scanning electron microscopes. Photomicrographs of these sections show the morphology of the organic phase and its location within the sand matrix. The photographs from both experimental techniques reveal that in the saturated zone large amounts of residual organic liquid are trapped as isolated blobs of microscopic size. The size, shape, and spatial distribution of these blobs of residual organic liquid affect the dissolution of organic liquid into the water phase and the biotransformation of organic components. These processes are of concern for the prediction of pollution migration and the design of aquifer remediation schemes

An empirical analysis of macroeconomic and bank-specific factors affecting liquidity of Indian banks

Directory of Open Access Journals (Sweden)

Anamika Singh

2016-06-01

Full Text Available This paper investigates bank-specific and macroeconomic factors that determine the liquidity of Indian banks. To explore the association, we perform OLS, fixed effect and random effect estimates on a data set of 59 banks from 2000 to 2013. Studied bank-specific factors include bank size, profitability, cost of funding, capital adequacy and deposits. GDP, inflation and unemployment are the macroeconomic factors considered. We also perform liquidity trend analysis of Indian banks based on ownership. Findings reveal that bank ownership affects liquidity of banks. Based on panel data analysis, we suggest that bank-specific (except cost of funding and macroeconomic (except unemployment factors significantly affect bank liquidity. These include bank size, deposits, profitability, capital adequacy, GDP and inflation. Further, bank size and GDP were found to have a negative effect on bank liquidity. On the other hand, deposits, profitability, capital adequacy and inflation showed a positive effect on bank liquidity. Cost of funding and unemployment showed an insignificant effect on bank liquidity. Our paper highlights new facts for enhanced understanding of liquidity in emerging economies like India.

Accelerator-based Single-shot Ultrafast Transmission Electron Microscope with Picosecond Temporal Resolution and Nanometer Spatial Resolution

OpenAIRE

Xiang, D.; Fu, F.; Zhang, J.; Huang, X.; Wang, L.; Wang, X.; Wan, W.

2014-01-01

We present feasibility study of an accelerator-based ultrafast transmission electron microscope (u-TEM) capable of producing a full field image in a single-shot with simultaneous picosecond temporal resolution and nanometer spatial resolution. We study key physics related to performance of u-TEMs, and discuss major challenges as well as possible solutions for practical realization of u-TEMs. The feasibility of u-TEMs is confirmed through simulations using realistic electron beam parameters. W...

Additional band broadening of peptides in the first size-exclusion chromatographic dimension of an automated stop-flow two-dimensional high performance liquid chromatography.

Science.gov (United States)

Xu, Jucai; Sun-Waterhouse, Dongxiao; Qiu, Chaoying; Zhao, Mouming; Sun, Baoguo; Lin, Lianzhu; Su, Guowan

2017-10-27

The need to improve the peak capacity of liquid chromatography motivates the development of two-dimensional analysis systems. This paper presented a fully automated stop-flow two-dimensional liquid chromatography system with size exclusion chromatography followed by reversed phase liquid chromatography (SEC×RPLC) to efficiently separate peptides. The effects of different stop-flow operational parameters (stop-flow time, peak parking position, number of stop-flow periods and column temperature) on band broadening in the first dimension (1 st D) SEC column were quantitatively evaluated by using commercial small proteins and peptides. Results showed that the effects of peak parking position and the number of stop-flow periods on band broadening were relatively small. Unlike stop-flow analysis of large molecules with a long running time, additional band broadening was evidently observed for small molecule analytes due to the relatively high effective diffusion coefficient (D eff ). Therefore, shorter analysis time and lower 1 st D column temperature were suggested for analyzing small molecules. The stop-flow two-dimensional liquid chromatography (2D-LC) system was further tested on peanut peptides and an evidently improved resolution was observed for both stop-flow heart-cutting and comprehensive 2D-LC analysis (in spite of additional band broadening in SEC). The stop-flow SEC×RPLC, especially heart-cutting analysis with shorter analysis time and higher 1 st D resolution for selected fractions, offers a promising approach for efficient analysis of complex samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Towards early detection of the hydrolytic degradation of poly(bisphenol A)carbonate by hyphenated liquid chromatography and comprehensive two-dimensional liquid chromatography

NARCIS (Netherlands)

Coulier, L.; Kaal, E.R.; Hankemeier, Th.

2006-01-01

The hydrolytic degradation of poly(bisphenol A)carbonate (PC) has been characterized by various liquid chromatography techniques. Size exclusion chromatography (SEC) showed a significant decrease in molecular mass as a result of hydrolytic degradation, while 'liquid chromatography at critical

X-ray diffraction and high resolution transmission electron microscopy characterization of intermetallics formed in Fe/Ti nanometer-scale multilayers during thermal annealing

International Nuclear Information System (INIS)

Wu, Z.L.; Peng, T.X.; Cao, B.S.; Lei, M.K.

2009-01-01

Intermetallics formation in the Fe/Ti nanometer-scale multilayers magnetron-sputtering deposited on Si(100) substrate during thermal annealing at 623-873 K was investigated by using small and wide angle X-ray diffraction and cross-sectional high-resolution transmission electron microscopy. The Fe/Ti nanometer-scale multilayers were constructed with bilayer thickness of 16.2 nm and the sublayer thickness ratio of 1:1. At the annealing temperature of 623 K, intermetallics FeTi were formed by nucleation at the triple joins of α-Fe(Ti)/α-Ti interface and α-Ti grain boundary with an orientational correlation of FeTi(110)//α-Ti(100) and FeTi[001]//α-Ti[001] to adjacent α-Ti grains. The lateral growth of intermetallics FeTi which is dependent on the diffusion path of Ti led to a coalescence into an intermetallic layer. With an increase in the annealing temperature, intermetallics Fe 2 Ti were formed between the intermetallics FeTi and the excess Fe due to the limitation of Fe and Ti atomic concentrations, resulting in the coexistence of intermetallics FeTi and Fe 2 Ti. It was found that the low energy interface as well as the dominant diffusion path constrained the nucleation and growth of intermetallics during interfacial reaction in the nanometer-scale metallic multilayers.

Explosive Boiling of Superheated Cryogenic Liquids

CERN Document Server

Baidakov, V G

2007-01-01

The monograph is devoted to the description of the kinetics of spontaneous boiling of superheated liquefied gases and their solutions. Experimental results are given on the temperature of accessible superheating, the limits of tensile strength of liquids due to processes of cavitation and the rates of nucleation of classical and quantum liquids. The kinetics of evolution of the gas phase is studied in detail for solutions of cryogenic liquids and gas-saturated fluids. The properties of the critical clusters (bubbles of critical sizes) of the newly evolving gas phase are analyzed for initial st

Evaporation of liquid droplets of nano- and micro-meter size as a function of molecular mass and intermolecular interactions: experiments and molecular dynamics simulations.

Science.gov (United States)

Hołyst, Robert; Litniewski, Marek; Jakubczyk, Daniel

2017-09-13

Transport of heat to the surface of a liquid is a limiting step in the evaporation of liquids into an inert gas. Molecular dynamics (MD) simulations of a two component Lennard-Jones (LJ) fluid revealed two modes of energy transport from a vapour to an interface of an evaporating droplet of liquid. Heat is transported according to the equation of temperature diffusion, far from the droplet of radius R. The heat flux, in this region, is proportional to temperature gradient and heat conductivity in the vapour. However at some distance from the interface, Aλ, (where λ is the mean free path in the gas), the temperature has a discontinuity and heat is transported ballistically i.e. by direct individual collisions of gas molecules with the interface. This ballistic transport reduces the heat flux (and consequently the mass flux) by the factor R/(R + Aλ) in comparison to the flux obtained from temperature diffusion. Thus it slows down the evaporation of droplets of sizes R ∼ Aλ and smaller (practically for sizes from 10 3 nm down to 1 nm). We analyzed parameter A as a function of interactions between molecules and their masses. The rescaled parameter, A(k B T b /ε 11 ) 1/2 , is a linear function of the ratio of the molecular mass of the liquid molecules to the molecular mass of the gas molecules, m 1 /m 2 (for a series of chemically similar compounds). Here ε 11 is the interaction parameter between molecules in the liquid (proportional to the enthalpy of evaporation) and T b is the temperature of the gas in the bulk. We tested the predictions of MD simulations in experiments performed on droplets of ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol. They were suspended in an electrodynamic trap and evaporated into dry nitrogen gas. A changes from ∼1 (for ethylene glycol) to approximately 10 (for tetraethylene glycol) and has the same dependence on molecular parameters as obtained for the LJ fluid in MD simulations. The value of x = A

Droplet size prediction in ultrasonic nebulization for non-oxide ceramic powder synthesis.

Science.gov (United States)

Muñoz, Mariana; Goutier, Simon; Foucaud, Sylvie; Mariaux, Gilles; Poirier, Thierry

2018-03-01

Spray pyrolysis process has been used for the synthesis of non-oxide ceramic powders from liquid precursors in the Si/C/N system. Particles with a high thermal stability and with variable composition and size distribution have been obtained. In this process, the mechanisms involved in precursor decomposition and gas phase recombination of species are still unknown. The final aim of this work consists in improving the whole process comprehension by an experimental/modelling approach that helps to connect the synthesized particles characteristics to the precursor properties and process operating parameters. It includes the following steps: aerosol formation by a piezoelectric nebulizer, its transport and the chemical-physical phenomena involved in the reaction processes. This paper focuses on the aerosol characterization to understand the relationship between the liquid precursor properties and the liquid droplet diameter distribution. Liquids with properties close to the precursor of interest (hexamethyldisilazane) have been used. Experiments have been performed using a shadowgraphy technique to determine the drop size distribution of the aerosol. For all operating parameters of the nebulizer device and liquids used, bimodal droplet size distributions have been obtained. Correlations proposed in the literature for the droplet size prediction by ultrasonic nebulization were used and adapted to the specific nebulizer device used in this study, showing rather good agreement with experimental values. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid jets for experiments on complex fluids

International Nuclear Information System (INIS)

Steinke, Ingo

2015-02-01

The ability of modern storage rings and free-electron lasers to produce intense X-ray beams that can be focused down to μm and nm sizes offers the possibility to study soft condensed matter systems on small length and short time scales. Gas dynamic virtual nozzles (GDVN) offer the unique possibility to investigate complex fluids spatially confined in a μm sized liquid jet with high flow rates, high pressures and shear stress distributions. In this thesis two different applications of liquid jet injection systems have been studied. The influence of the shear flow present in a liquid jet on colloidal dispersions was investigated via small angle X-ray scattering and a coherent wide angle X-ray scattering experiment on a liquid water jet was performed. For these purposes, liquid jet setups that are capable for X-ray scattering experiments have been developed and the manufacturing of gas dynamic virtual nozzles was realized. The flow properties of a liquid jet and their influences on the liquid were studied with two different colloidal dispersions at beamline P10 at the storage ring PETRA III. The results show that high shear flows present in a liquid jet lead to compressions and expansions of the particle structure and to particle alignments. The shear rate in the used liquid jet could be estimated to γ ≥ 5.4 . 10 4 Hz. The feasibility of rheology studies with a liquid jet injection system and the combined advantages is discussed. The coherent X-ray scattering experiment on a water jet was performed at the XCS instrument at the free-electron laser LCLS. First coherent single shot diffraction patterns from water were taken to investigate the feasibility of measuring speckle patterns from water.

Physical property, phase equilibrium, distillation. Measurement and prediction of vapor-liquid and liquid-liquid equilibria; Bussei / heiko / joryu. Kieki, ekieki heiko no sokutei to suisan

Energy Technology Data Exchange (ETDEWEB)

Tochigi, K. [Nihon Univ., Tokyo (Japan)

1998-08-05

The data on vapor-liquid equilibrium are basic data indispensable to the designing of a distillation process. The stage required for separation depends greatly upon the x-y curve, and the existence/nonexistence of an azeotropic point is also an important item to be checked. This paper describes the measurement of vapor-liquid equilibrium and liquid-liquid equilibrium, and then introduces reliable data on vapor-liquid equilibrium and parameters of an activity coefficient formula. For the prediction of vapor-liquid equilibrium, the ASOG, UNIFAC, and modified NIFAC, all being group contributive methods are utilized. The differences between these group contributive methods are based on the differences between the contributive items based on the differences in size of molecules influencing the activity coefficients and the expression of the group activity coefficient formula. The applicable number of groups of the ASOG is 43, while that of groups of the UNIFAC is 50. The modified UNIFAC covers 43 groups. The prediction of liquid-liquid equilibrium by using a group contributive method has little progressed since the of the results of the study of Magnussen et al. using the UNIFAC. 12 refs., 8 figs., 1 tab.

Nanometer scale thermometry in a living cell

Science.gov (United States)

Kucsko, G.; Maurer, P. C.; Yao, N. Y.; Kubo, M.; Noh, H. J.; Lo, P. K.; Park, H.; Lukin, M. D.

2014-01-01

Sensitive probing of temperature variations on nanometer scales represents an outstanding challenge in many areas of modern science and technology1. In particular, a thermometer capable of sub-degree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool for many areas of biological, physical and chemical research; possibilities range from the temperature-induced control of gene expression2–5 and tumor metabolism6 to the cell-selective treatment of disease7,8 and the study of heat dissipation in integrated circuits1. By combining local light-induced heat sources with sensitive nanoscale thermometry, it may also be possible to engineer biological processes at the sub-cellular level2–5. Here, we demonstrate a new approach to nanoscale thermometry that utilizes coherent manipulation of the electronic spin associated with nitrogen-vacancy (NV) color centers in diamond. We show the ability to detect temperature variations down to 1.8 mK (sensitivity of 9mK/Hz) in an ultra-pure bulk diamond sample. Using NV centers in diamond nanocrystals (nanodiamonds, NDs), we directly measure the local thermal environment at length scales down to 200 nm. Finally, by introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, we demonstrate temperature-gradient control and mapping at the sub-cellular level, enabling unique potential applications in life sciences. PMID:23903748

The length and time scales of water's glass transitions

Science.gov (United States)

Limmer, David T.

2014-06-01

Using a general model for the equilibrium dynamics of supercooled liquids, I compute from molecular properties the emergent length and time scales that govern the nonequilibrium relaxation behavior of amorphous ice prepared by rapid cooling. Upon cooling, the liquid water falls out of equilibrium whereby the temperature dependence of its relaxation time is predicted to change from super-Arrhenius to Arrhenius. A consequence of this crossover is that the location of the apparent glass transition temperature depends logarithmically on cooling rate. Accompanying vitrification is the emergence of a dynamical length-scale, the size of which depends on the cooling rate and varies between angstroms and tens of nanometers. While this protocol dependence clarifies a number of previous experimental observations for amorphous ice, the arguments are general and can be extended to other glass forming liquids.

The length and time scales of water's glass transitions.

Science.gov (United States)

Limmer, David T

2014-06-07

Using a general model for the equilibrium dynamics of supercooled liquids, I compute from molecular properties the emergent length and time scales that govern the nonequilibrium relaxation behavior of amorphous ice prepared by rapid cooling. Upon cooling, the liquid water falls out of equilibrium whereby the temperature dependence of its relaxation time is predicted to change from super-Arrhenius to Arrhenius. A consequence of this crossover is that the location of the apparent glass transition temperature depends logarithmically on cooling rate. Accompanying vitrification is the emergence of a dynamical length-scale, the size of which depends on the cooling rate and varies between angstroms and tens of nanometers. While this protocol dependence clarifies a number of previous experimental observations for amorphous ice, the arguments are general and can be extended to other glass forming liquids.

Modeling of liquid phases

CERN Document Server

Soustelle, Michel

2015-01-01

This book is part of a set of books which offers advanced students successive characterization tool phases, the study of all types of phase (liquid, gas and solid, pure or multi-component), process engineering, chemical and electrochemical equilibria, and the properties of surfaces and phases of small sizes. Macroscopic and microscopic models are in turn covered with a constant correlation between the two scales. Particular attention has been given to the rigor of mathematical developments. This second volume in the set is devoted to the study of liquid phases.

Maskless X-Ray Writing of Electrical Devices on a Superconducting Oxide with Nanometer Resolution and Online Process Monitoring.

Science.gov (United States)

Mino, Lorenzo; Bonino, Valentina; Agostino, Angelo; Prestipino, Carmelo; Borfecchia, Elisa; Lamberti, Carlo; Operti, Lorenza; Fretto, Matteo; De Leo, Natascia; Truccato, Marco

2017-08-22

X-ray nanofabrication has so far been usually limited to mask methods involving photoresist impression and subsequent etching. Herein we show that an innovative maskless X-ray nanopatterning approach allows writing electrical devices with nanometer feature size. In particular we fabricated a Josephson device on a Bi 2 Sr 2 CaCu 2 O 8+δ (Bi-2212) superconducting oxide micro-crystal by drawing two single lines of only 50 nm in width using a 17.4 keV synchrotron nano-beam. A precise control of the fabrication process was achieved by monitoring in situ the variations of the device electrical resistance during X-ray irradiation, thus finely tuning the irradiation time to drive the material into a non-superconducting state only in the irradiated regions, without significantly perturbing the crystal structure. Time-dependent finite element model simulations show that a possible microscopic origin of this effect can be related to the instantaneous temperature increase induced by the intense synchrotron picosecond X-ray pulses. These results prove that a conceptually new patterning method for oxide electrical devices, based on the local change of electrical properties, is actually possible with potential advantages in terms of heat dissipation, chemical contamination, miniaturization and high aspect ratio of the devices.

Drop size measurements in Venturi scrubbers

Energy Technology Data Exchange (ETDEWEB)

Fernandez Alonso, D.; Azzopardi, B.J. [Nottingham Univ. (United Kingdom). Dept. of Chemical Engineering; Goncalves, J.A.S.; Coury, J.R. [Universidade Federal de Sao Carlos (Brazil). Departamento de Engenharia Quimica

2001-07-01

Venturi scrubbers are high efficiency gas cleaners in which suspended particles are removed from gas streams by drops formed by liquid atomisation, usually in the Venturi throat. The size of the drops formed are of fundamental importance to the performance of the equipment, both in terms of pressure drop and dust removal efficiency. In this study, drop sizes in a cylindrical laboratory-scale Venturi scrubber were measured using a laser diffraction technique. Gas velocity and liquid to gas ratios varied from 50 to 90 m/s and 0.5 to 2.0 1/m{sup 3}, respectively. Water was injected using two different arrangements: either as jets in the throat or as a film just upstream of the convergence. Drop size measurements were performed at three positions in the case of jet injection: two located along the throat, and the last one at the end of the diffuser. The present data shows that the Sauter mean diameter of the spray can be well correlated by the equation of Boll et al. (J. Air Pollut. Control Assoc. 24 (1974) 932). Drop size distributions are satisfactorily represented by a Rosin-Rammler function. This paper also provides a simple method for calculating the parameters of the Rosin-Rammler function. As a result of this work, drop sizes in Venturi scrubbers can be estimated with much higher accuracy. (Author)

Chemical composition shape form and size of suspended solids in the atmosphere carried by rain water

International Nuclear Information System (INIS)

Iturbe G, J.L.; Lopez M, B.E.; Torre O, J. De la

2001-01-01

The interest of this work is to know about shape form, size and chemical composition of the suspended solids in the atmosphere of Toluca city and which are carried by the rains. The harvest of the samples was carried out during january to november 1999. The separation of the particulate matter from the rain water was realized through centrifugation. The solids were analysed by Scanning Electron Microscopy to know the shape form and size and the chemical composition was determined by X-ray dispersive energy in general form and of some particles individually analysed. The p H was measured to the solutions and the quantification of some dissolved ions by the Icp technique was realized. The results of the solids showed C, O, Na, Mg, Al, Si, S, P, K, Ca, Ti and Fe. Moreover they present sizes which varying from a ten of nanometers until some tens of microns. (Author)

The influence of pore size and surface area of activated carbons on the performance of ionic liquid based supercapacitors.

Science.gov (United States)

Pohlmann, Sebastian; Lobato, Belén; Centeno, Teresa A; Balducci, Andrea

2013-10-28

This study analyses and compares the behaviour of 5 commercial porous carbons in the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) and its mixture with propylene carbonate (PC) as electrolytes. The results of this investigation show that the existence of a distribution of pore sizes and/or constrictions at the entrance of the pores leads to significant changes in the specific capacitance of the investigated materials. The use of PYR14TFSI as an electrolyte has a positive effect on the EDLC energy storage, but its high viscosity limits the power density. The mixture 50 : 50 wt% propylene carbonate-PYR14TFSI provides high operative voltage as well as low viscosity and thus notably enhances EDLC operation.

[Clinical observation on nanometer acupoint mounting method for alleviation of myospasm complicated by spinal injury].

Science.gov (United States)

Zhang, Su-Jie; Si, Tong; Li, Zhi

2008-11-01

To observe clinical effect of nanometer acupoint mounting method for alleviation of myospasm complicated by spinal injury. Sixty cases were randomly divided into an observation group and a control group, 30 cases in each group. The observation group were treated by nanometer mounting at 4 Jiaji (EX-B 2) points each on both sides of the affected spine and Shenshu (BL 23), Shangliao (BL 31), Ciliao (BL 32), Yang-lingquan (GB 34), Xuanzhong (GB 39); and the control group by mounting zinc oxide sticking tablets at the above acupoints. The mounting was replaced once each two days, 7 times constituting one course. One week and one month after the end of 3 courses, their results were recorded, respectively. Before treatment, there was no significant difference between the two groups in grades of the myospasm degree (P > 0.05). One week after the end of treatment, 15 cases were grade I of myospasm, 9 cases were grade II, 5 cases were grade III and 1 case was grade IV in the observation group, and 1 cases grade I, 7 cases grade II, 14 cases grade III, 8 cases grade IV in the control group. Ridit analysis on the data indicated that there were significant differences before and after treatment in the myospasm degree (P mounting method is a new one for alleviation of myospasm complicated by spinal injury, with convenience, safety and no side effect.

Fluctuating hydrodynamics for ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Lazaridis, Konstantinos [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States); Wickham, Logan [Department of Computer Science, Washington State University, Richland, 99354 (United States); Voulgarakis, Nikolaos, E-mail: n.voulgarakis@wsu.edu [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States)

2017-04-25

We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau–Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids. - Highlights: • A new fluctuating hydrodynamics method for ionic liquids. • Description of ionic liquid morphology in bulk and near electrified surfaces. • Direct comparison with experimental measurements.

Investigation on the photocatalytic degradation of pyrene on soil surfaces using nanometer anatase TiO2 under UV irradiation

International Nuclear Information System (INIS)

Dong Dianbo; Li Peijun; Li Xiaojun; Zhao Qing; Zhang Yinqiu; Jia Chunyun; Li Peng

2010-01-01

Photocatalytic degradation of pyrene on soil surfaces was investigated in the presence of nanometer anatase TiO 2 under a variety of conditions. After being spiked with pyrene, soil samples loaded with different amounts of TiO 2 (0%, 1%, 2%, 3%, and 4%, w/w) were exposed to UV irradiation for 25 h. The results indicated that the photocatalytic degradation of pyrene followed pseudo-first-order kinetics. TiO 2 accelerated the degradation of pyrene generally as indicated by the half-life reduction from 45.90 to 31.36 h, corresponding to the TiO 2 amounts from 0% to 4%, respectively. The effects of H 2 O 2 , light intensity and humic acids on the degradation of pyrene were also investigated. The degradation of pyrene increased along with increasing the concentration of H 2 O 2 , light intensity and the concentration of humic acids. All results indicated that the photocatalytic method in the presence of nanometer anatase TiO 2 was an advisable choice for the treatments of PAHs polluted soil in the future.

Synthesis and Properties of Platinum Nanoparticles by Pulsed Laser Ablation in Liquid

Directory of Open Access Journals (Sweden)

Maria Isabel Mendivil Palma

2016-01-01

Full Text Available Platinum (Pt nanoparticles were synthesized by pulsed laser ablation in liquid (PLAL technique in different liquids (acetone, ethanol, and methanol. Ablation was performed using a Q-switched Nd:YAG laser with output energy of 230 mJ/pulse for 532 nm wavelength. Ablation time and laser energy fluence were varied for all the liquids. Effects of laser energy fluence, ablation time, and nature of the liquid were reported. The mean size, size distributions, shape, elemental composition, and optical properties of Pt nanoparticles synthesized by PLAL were examined by transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and UV-Visible absorption spectroscopy.

Self-assembled metallic nanoparticle template — a new approach of surface nanostructuring at nanometer scale

Directory of Open Access Journals (Sweden)

A. Taleb

2017-09-01

Full Text Available In the present work, the formation of silver and copper nanostructures on highly oriented pyrolytic graphite (HOPG modified with self-assembled gold nanoparticles (Au NPs is demonstrated. Surface patterning with nanometer resolution was achieved. Different methods such as field emission scanning electron microscopy (FEGSEM, energy dispersive spectrometry (EDS and X-ray photoelectron spectroscopy (XPS were used to illustrate a selective deposition of silver and copper on Au NPs. The mechanism of silver and copper ions reduction on Au NP with n-dodecanethiol coating is discussed.

Foil bearing performance in liquid nitrogen and liquid oxygen

Science.gov (United States)

Genge, Gary G.; Saville, Marshall; Gu, Alston

1993-01-01

Space transfer vehicles and other power and propulsion systems require long-life turbopumps. Rolling-element bearings used in current turbopumps do not have sufficient life for these applications. Process fluid foil bearings have established long life, with exceptional reliability, over a wide range of temperatures and fluids in many high-speed turbomachinery applications. However, actual data on bearing performance in cryogenic fluids has been minimal. The National Aeronautics and Space Administration (NASA) and AlliedSignal Aerospace Systems and Equipment (ASE) have attempted to characterize the leaf-type compliant foil bearing in oxygen and nitrogen. The work performed under a joint internal research and development program between Marshall Space Flight Center (MSFC) and ASE demonstrated that the foil bearing has load capacities of at least 266 psi in liquid oxygen and 352 psi in liquid nitrogen. In addition, the bearing demonstrated a direct damping coefficient of 40 to 50 lb-sec/in. with a damping ratio of .7 to 1.4 in. liquid nitrogen using a bearing sized for upper-stage turbopumps. With the results from this testing and the years of successful use in air cycle machines and other applications, leaf-type compliant foil bearings are ready for testing in liquid oxygen turbopumps.

Effects of laser fluence and liquid media on preparation of small Ag nanoparticles by laser ablation in liquid

Science.gov (United States)

Moura, Caroline Gomes; Pereira, Rafael Santiago Floriani; Andritschky, Martin; Lopes, Augusto Luís Barros; Grilo, João Paulo de Freitas; Nascimento, Rubens Maribondo do; Silva, Filipe Samuel

2017-12-01

This study aims to assess a method for preparation of small and highly stable Ag nanoparticles by nanosecond laser ablation in liquid. Effect of liquid medium and laser fluence on the size, morphology and structure of produced nanoparticles has been studied experimentally. Pulses of a Nd:YAG laser of 1064 nm wavelength at 35 ns pulse width at different fluences were employed to irradiate the silver target in different environments (water, ethanol and acetone). The UV-Visible absorption spectra of nanoparticles exhibit surface plasmon resonance absorption peak in the UV region. STEM and TEM micrographs were used to evaluate the size and shape of nanoparticles. The stability of silver colloids in terms of oxidation at different liquid media was analyzed by SAED patterns. The results showed that characteristics of Ag nanoparticles and their production rate were strongly influenced by varying laser fluence and liquid medium. Particles from 2 to 80 nm of diameter were produced using different conditions and no oxidation was found in ethanol and acetone media. This work puts in evidence a promising approach to produce small nanoparticles by using high laser fluence energy.

Sub-nanometer resolution XPS depth profiling: Sensing of atoms

Energy Technology Data Exchange (ETDEWEB)

Szklarczyk, Marek, E-mail: szklarcz@chem.uw.edu.pl [Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw (Poland); Shim-Pol, ul. Lubomirskiego 5, 05-080 Izabelin (Poland); Macak, Karol; Roberts, Adam J. [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom); Takahashi, Kazuhiro [Kratos XPS Section, Shimadzu Corp., 380-1 Horiyamashita, Hadano, Kanagawa 259-1304 (Japan); Hutton, Simon [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom); Głaszczka, Rafał [Shim-Pol, ul. Lubomirskiego 5, 05-080 Izabelin (Poland); Blomfield, Christopher [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom)

2017-07-31

Highlights: • Angle resolved photoelectron depth profiling of nano thin films. • Sensing atomic position in SAM films. • Detection of direction position of adsorbed molecules. - Abstract: The development of a method capable of distinguishing a single atom in a single molecule is important in many fields. The results reported herein demonstrate sub-nanometer resolution for angularly resolved X-ray photoelectron spectroscopy (ARXPS). This is made possible by the incorporation of a Maximum Entropy Method (MEM) model, which utilize density corrected electronic emission factors to the X-ray photoelectron spectroscopy (XPS) experimental results. In this paper we report on the comparison between experimental ARXPS results and reconstructed for both inorganic and organic thin film samples. Unexpected deviations between experimental data and calculated points are explained by the inaccuracy of the constants and standards used for the calculation, e.g. emission factors, scattering intensity and atomic density through the studied thickness. The positions of iron, nitrogen and fluorine atoms were determined in the molecules of the studied self-assembled monolayers. It has been shown that reconstruction of real spectroscopic data with 0.2 nm resolution is possible.

Liquid agents for dispersion of hard alloys

International Nuclear Information System (INIS)

Putintseva, M.N.

2006-01-01

Effects of dispersant properties on granulometric, chemical, and phase composition of the products of WC hard alloy electroerosion are considered. It is established that an increase of liquid dispersant permittivity results in enhanced powder dispersity, and an increase of boiling temperature and kinematic viscosity of a hydrocarbon liquid promotes a carbon loss from WC and intensifies pyrolysis of the liquid.On electroerosion of WC base hard alloy in oil a powder particle consists of b-WC+W 2 C phases, in kerosine - of a-WC+b-WC, in distilled water - of W+W 2 C. The viscosity of liquid dispersants practically has no effect on powder particle size [ru

Solvency and Liquidity Level Trade-off: Does it Exist in Croatian Banking Sector?

Directory of Open Access Journals (Sweden)

Kundid Novokmet Ana

2016-11-01

Full Text Available We focus on 32 Croatian banks in the period 2002-2010 in order to investigate the solvency-liquidity nexus. Dynamic panel data analysis is applied on two basic models in which current liquidity ratio and equity to assets ratio are set as dependent variables, interchangeably, and other explanatory variables employed to capture the effect of bank size, profitability and asset quality as well as macroeconomic environment. We found two-way positive relationship between bank solvency and liquidity. However, bank size plays an important role in the capital and liquidity management, and trade-off between the solvency and liquidity level is found for the larger banks. Therefore, policymakers should take into consideration capital and liquidity interdependence, as well as the bank size effect when designing capital and liquidity requirements in order to downsize the regulatory burden for smaller banks, and increase them for larger banks. Namely, larger banks tend to minimize regulatory costs by avoiding simultaneous increase of liquidity and solvency. Small banks do exactly the opposite and stock both, capital and liquidity, what potentially makes their funds allocation sub-optimal, from their own as well as social point of view. Altogether, the paper contributes to scarce empirical evidence regarding bank solvency and liquidity interdependence, particularly when the post-transitional banking sectors are taken into consideration. It adds to knowledge on bank financial management in praxis, and bank managers and prudential authorities might find it relevant for their policies design and implementation.

Luminescent Oxygen Gas Sensors Based on Nanometer-Thick Hybrid Films of Iridium Complexes and Clay Minerals

Directory of Open Access Journals (Sweden)

Hisako Sato

2014-01-01

Full Text Available The use of Ir(III complexes in photo-responsive molecular devices for oxygen gas sensing is reviewed. Attention is focused on the immobilization of Ir(III complexes in organic or inorganic host materials such as polymers, silica and clays in order to enhance robustness and reliability. Our recent works on constructing nanometer-thick films comprised of cyclometalated cationic Ir(III complexes and clay minerals are described. The achievement of multi-emitting properties in response to oxygen pressure is demonstrated.

Real-time detection of antibiotic activity by measuring nanometer-scale bacterial deformation

Science.gov (United States)

Iriya, Rafael; Syal, Karan; Jing, Wenwen; Mo, Manni; Yu, Hui; Haydel, Shelley E.; Wang, Shaopeng; Tao, Nongjian

2017-12-01

Diagnosing antibiotic-resistant bacteria currently requires sensitive detection of phenotypic changes associated with antibiotic action on bacteria. Here, we present an optical imaging-based approach to quantify bacterial membrane deformation as a phenotypic feature in real-time with a nanometer scale (˜9 nm) detection limit. Using this approach, we found two types of antibiotic-induced membrane deformations in different bacterial strains: polymyxin B induced relatively uniform spatial deformation of Escherichia coli O157:H7 cells leading to change in cellular volume and ampicillin-induced localized spatial deformation leading to the formation of bulges or protrusions on uropathogenic E. coli CFT073 cells. We anticipate that the approach will contribute to understanding of antibiotic phenotypic effects on bacteria with a potential for applications in rapid antibiotic susceptibility testing.

An electro-active paper actuator made with cellulose–polypyrrole–ionic liquid nanocomposite: influence of ionic liquid concentration, type of anion and humidity

International Nuclear Information System (INIS)

Mahadeva, Suresha K; Kim, Jaehwan

2010-01-01

This paper reports a cellulose–polypyrrole–ionic liquid (CPIL) nanocomposite that can produce large actuating displacement in a low humidity environment. The fabrication process and actuator performance of the CPIL nanocomposite actuator are illustrated. Experimental results revealed that the size of anion, concentration of ionic liquid and ambient humidity level have a significant influence on the actuator performance of the CPIL nanocomposite. The bending displacement of the CPIL nanocomposite actuator was enhanced with increasing anion size, ionic liquid concentration and humidity level. CPIL nanocomposite made with 4% BMIBF 4 ionic liquid exhibited a very large bending displacement with excellent durability under ambient conditions (30% relative humidity and 25 °C). This is probably the first report that cellulose based electro-active paper actuator can exhibit such a large bending displacement under ambient conditions. Experimental results revealed that the proposed CPIL nanocomposite actuator under study can be operated up to 70% humidity level

Basel liquidity regulation: was it improved with the 2013 revisions?

OpenAIRE

Kowalik, Michal

2013-01-01

The Basel III Accord of December 2010, aiming to reduce the chances of systemic financial crises, included provisions regulating the liquid assets held by financial institutions. The Accord included provisions requiring financial institutions to maintain liquidity buffers: stocks of liquid assets sufficient to cover 30 days of cash outflow in a financial "stress event." ; The Accord was revised in January 2013, with new provisions regarding the size, composition and availability of liquidity ...

Towards nanometer-spaced silicon contacts to proteins

Science.gov (United States)

Schukfeh, Muhammed I.; Sepunaru, Lior; Behr, Pascal; Li, Wenjie; Pecht, Israel; Sheves, Mordechai; Cahen, David; Tornow, Marc

2016-03-01

A vertical nanogap device (VND) structure comprising all-silicon contacts as electrodes for the investigation of electronic transport processes in bioelectronic systems is reported. Devices were fabricated from silicon-on-insulator substrates whose buried oxide (SiO2) layer of a few nanometers in thickness is embedded within two highly doped single crystalline silicon layers. Individual VNDs were fabricated by standard photolithography and a combination of anisotropic and selective wet etching techniques, resulting in p+ silicon contacts, vertically separated by 4 or 8 nm, depending on the chosen buried oxide thickness. The buried oxide was selectively recess-etched with buffered hydrofluoric acid, exposing a nanogap. For verification of the devices’ electrical functionality, gold nanoparticles were successfully trapped onto the nanogap electrodes’ edges using AC dielectrophoresis. Subsequently, the suitability of the VND structures for transport measurements on proteins was investigated by functionalizing the devices with cytochrome c protein from solution, thereby providing non-destructive, permanent semiconducting contacts to the proteins. Current-voltage measurements performed after protein deposition exhibited an increase in the junctions’ conductance of up to several orders of magnitude relative to that measured prior to cytochrome c immobilization. This increase in conductance was lost upon heating the functionalized device to above the protein’s denaturation temperature (80 °C). Thus, the VND junctions allow conductance measurements which reflect the averaged electronic transport through a large number of protein molecules, contacted in parallel with permanent contacts and, for the first time, in a symmetrical Si-protein-Si configuration.

Towards nanometer-spaced silicon contacts to proteins

International Nuclear Information System (INIS)

Schukfeh, Muhammed I; Behr, Pascal; Tornow, Marc; Sepunaru, Lior; Li, Wenjie; Pecht, Israel; Sheves, Mordechai; Cahen, David

2016-01-01

A vertical nanogap device (VND) structure comprising all-silicon contacts as electrodes for the investigation of electronic transport processes in bioelectronic systems is reported. Devices were fabricated from silicon-on-insulator substrates whose buried oxide (SiO_2) layer of a few nanometers in thickness is embedded within two highly doped single crystalline silicon layers. Individual VNDs were fabricated by standard photolithography and a combination of anisotropic and selective wet etching techniques, resulting in p"+ silicon contacts, vertically separated by 4 or 8 nm, depending on the chosen buried oxide thickness. The buried oxide was selectively recess-etched with buffered hydrofluoric acid, exposing a nanogap. For verification of the devices’ electrical functionality, gold nanoparticles were successfully trapped onto the nanogap electrodes’ edges using AC dielectrophoresis. Subsequently, the suitability of the VND structures for transport measurements on proteins was investigated by functionalizing the devices with cytochrome c protein from solution, thereby providing non-destructive, permanent semiconducting contacts to the proteins. Current–voltage measurements performed after protein deposition exhibited an increase in the junctions’ conductance of up to several orders of magnitude relative to that measured prior to cytochrome c immobilization. This increase in conductance was lost upon heating the functionalized device to above the protein’s denaturation temperature (80 °C). Thus, the VND junctions allow conductance measurements which reflect the averaged electronic transport through a large number of protein molecules, contacted in parallel with permanent contacts and, for the first time, in a symmetrical Si–protein–Si configuration. (paper)

Observation of nanometer-sized electro-active defects in insulating layers by fluorescence microscopy and electrochemistry.

Science.gov (United States)

Renault, Christophe; Marchuk, Kyle; Ahn, Hyun S; Titus, Eric J; Kim, Jiyeon; Willets, Katherine A; Bard, Allen J

2015-06-02

We report a method to study electro-active defects in passivated electrodes. This method couples fluorescence microscopy and electrochemistry to localize and size electro-active defects. The method was validated by comparison with a scanning probe technique, scanning electrochemical microscopy. We used our method for studying electro-active defects in thin TiO2 layers electrodeposited on 25 μm diameter Pt ultramicroelectrodes (UMEs). The permeability of the TiO2 layer was estimated by measuring the oxidation of ferrocenemethanol at the UME. Blocking of current ranging from 91.4 to 99.8% was achieved. Electro-active defects with an average radius ranging between 9 and 90 nm were observed in these TiO2 blocking layers. The distribution of electro-active defects over the TiO2 layer is highly inhomogeneous and the number of electro-active defect increases for lower degree of current blocking. The interest of the proposed technique is the possibility to quickly (less than 15 min) image samples as large as several hundreds of μm(2) while being able to detect electro-active defects of only a few tens of nm in radius.

Lyotropic chromonic liquid crystals: From viscoelastic properties to living liquid crystals

Science.gov (United States)

Zhou, Shuang

(LLC), constructed by mixing LCLC with self-propelled microorganism, bacteria strain called Bacillus subtilis . The coupling between bacterial flow and the nematic long-rang order of the LCLC matrix results in a wealth of intriguing dynamic phenomena, among which are 1) programmable trajectories of bacterial motion guided by patterned director field, 2) cargo particle transportation along such trajectories, 3) local melting of the liquid crystal caused by the bacteria-produced shear flow, 4) birefringence-enabled visualization of microflow generated by nanometer-thick bacterial flagella and 5) activity triggered transition from non-flow uniform state into a flowing one-dimensional pattern and its evolution into a turbulent array of topological defects. In addition, due to the long-rang elastic interaction mediated by the nematic matrix, LLC shows collective dynamics at very low fraction of bacteria, on the order of 0.2%, about 1/10 of bacteria fraction needed in isotropic media for collective motion. Our work suggests an unorthodox design concept to control and manipulate the dynamic behavior of soft active matter and opens the door for potential biosensing and biomedical applications.

Sub-Nanometer Channels Embedded in Two-Dimensional Materials

KAUST Repository

Han, Yimo

2017-07-31

Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically-thin p-n junctions2-7, metal-semiconductor contacts8-10, and metal-insulator barriers11-13 have been demonstrated. While 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions are also necessary. Although external one-dimensional (1D) carbon nanotubes14 can be used to locally gate 2D materials, this adds a non-trivial third dimension, complicating device integration and flexibility. Here, we report the direct synthesis of sub-nanometer 1D MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalyzed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Molecular dynamics (MD) simulations have identified other combinations of 2D materials that could form 1D channels. Density function theory (DFT) calculation predicts these 1D channels display type II band alignment needed for carrier confinement and charge separation to access the ultimate length scales necessary for future electronic applications.

Size-dependent electronic properties of metal nanostructures

Indian Academy of Sciences (India)

Table of contents. Size-dependent electronic properties of metal nanostructures · Slide 2 · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19 · Nanocrystalline film at liquid-liquid interface · Slide 21 · Slide 22.

The influence of size on the toxicity of an encapsulated pesticide: a comparison of micron- and nano-sized capsules.

Science.gov (United States)

Meredith, Alicea N; Harper, Bryan; Harper, Stacey L

2016-01-01

Encapsulation technology involves entrapping a chemical active ingredient (a.i.) inside a hollow polymeric shell and has been applied to commercial pesticide manufacturing for years to produce capsule suspension (CS) formulations with average particle sizes in the micron-scale. The few literature sources that investigate the environmental fate and toxicity to non-target organisms of encapsulated commercially available pesticide products with regard to capsule size report on average sizes between 20 and 50 μm. Here, we have identified a CS formulation with an average capsule size of approximately 2 μm with some capsules extending into the nanometer scale (~200 nm). Determining how carrier size influences toxicity is important to understanding if current pesticide risk assessments are sufficient to protect against products that incorporate encapsulation technology. Here, a commercial pyrethroid CS pesticide with lambda-cyhalothrin (λ-Cy) as the a.i. was separated into two suspensions, a fraction consisting of nano-sized capsules (~250 nm) and a fraction of micron-sized capsules (~2200 nm) in order to investigate the influence of capsule size on toxicity to embryonic zebrafish, Danio rerio. Toxicity was evaluated 24h after exposure to equivalent amounts of a.i. by the presence and severity of pyrethroid-specific tremors, 14 sublethal developmental impacts and mortality. Fish exposed to greater than 20 μg a.i. L(-1) technical λ-Cy or formulated product experienced curvature of the body axis, pericardial edema, craniofacial malformations, and mortality. Exposure to the unfractionated formulation, micro fraction, nano fraction and technical a.i. resulted in no significant differences in the occurrence of sublethal impacts or mortality; however, the technical a.i. exposure resulted in significantly less fish experiencing tremors and shorter tremors compared to any of the formulated product exposures. This suggests that the capsule size does not influence the toxic

The influence of molecule size and structure on the lubricity of liquids: An experimental study

DEFF Research Database (Denmark)

Sivebæk, Ion Marius; Sorenson, Spencer C

2002-01-01

to stay liquid. Recently a lubricity test capable of handling DME was developed [1], as well as a volatile fuel viscometer [2]. As a result of this development it has become possible to test the lubricity of small hydrocarbons such as propane and butane as well as liquids with larger molecules...

ASSESING THE DETERMINANTS OF BANK LIQUIDITY. CASE STUDY ROMANIAN BANKING SYSTEM

Directory of Open Access Journals (Sweden)

Florin Alexandru LUCA

2016-06-01

Full Text Available The financial crisis has highlighted the importance of liquidity risk for the banking system. Therefore, this study focuses on identifing the determinants of liquidity of Romanian banks. The data cover the period from 2006 to 2013 and take into account only bank-specific factors. The empirical study was applied on 16 Romanian banks and based on previous studies and uses different liquidity ratios, encompassing different points of view on liquidity. Regarding the explanatory variables considered in this analysis, they include various items of internal character concerning: capital adequacy, asset quality, profitability, efficiency of financial intermediation and the size of the banks. The results of our regression analysis indicate that bank liquidity is positively related to capital adequacy of banks and bank profitability and negatively related to the rate of non-performing loans, net interest margin and the size of the bank.

The Determinants of Banks' Liquidity Buffers in Central America

OpenAIRE

Corinne Deléchat; Camila Henao; Priscilla Muthoora; Svetlana Vtyurina

2014-01-01

Banks’ liquidity holdings are comfortably above legal or prudential requirements in most Central American countries. While good for financial stability, high liquidity may nonetheless hinder financial market development and monetary policy transmission. Using a panel of 96 commercial banks from Central America, Panama and the Dominican Republic for 2006-2010, we find that the demand for precautionary liquidity buffers is associated with measures of bank’s size, profitability, capitalization, ...

Systems and methods for analyzing liquids under vacuum

Science.gov (United States)

Yu, Xiao-Ying; Yang, Li; Cowin, James P.; Iedema, Martin J.; Zhu, Zihua

2013-10-15

Systems and methods for supporting a liquid against a vacuum pressure in a chamber can enable analysis of the liquid surface using vacuum-based chemical analysis instruments. No electrical or fluid connections are required to pass through the chamber walls. The systems can include a reservoir, a pump, and a liquid flow path. The reservoir contains a liquid-phase sample. The pump drives flow of the sample from the reservoir, through the liquid flow path, and back to the reservoir. The flow of the sample is not substantially driven by a differential between pressures inside and outside of the liquid flow path. An aperture in the liquid flow path exposes a stable portion of the liquid-phase sample to the vacuum pressure within the chamber. The radius, or size, of the aperture is less than or equal to a critical value required to support a meniscus of the liquid-phase sample by surface tension.

Inorganic-Organic Molecules and Solids with Nanometer-Sized Pores

Energy Technology Data Exchange (ETDEWEB)

Maverick, Andrew W

2011-12-17

We are constructing porous inorganic-organic hybrid molecules and solids, many of which contain coordinatively unsaturated metal centers. In this work, we use multifunctional ²-diketone ligands as building blocks to prepare extended-solid and molecular porous materials that are capable of reacting with a variety of guest molecules.

Quantum size effects in TiO2 thin films grown by atomic layer deposition

Directory of Open Access Journals (Sweden)

Massimo Tallarida

2014-01-01

Full Text Available We study the atomic layer deposition of TiO2 by means of X-ray absorption spectroscopy. The Ti precursor, titanium isopropoxide, was used in combination with H2O on Si/SiO2 substrates that were heated at 200 °C. The low growth rate (0.15 Å/cycle and the in situ characterization permitted to follow changes in the electronic structure of TiO2 in the sub-nanometer range, which are influenced by quantum size effects. The modified electronic properties may play an important role in charge carrier transport and separation, and increase the efficiency of energy conversion systems.

The Importance of Ion Size and Electrode Curvature on Electrical Double Layers in Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

Feng, Guang [Clemson University; Qiao, Rui [ORNL; Huang, Jingsong [ORNL; Dai, Sheng [ORNL; Sumpter, Bobby G [ORNL; Meunier, Vincent [ORNL

2010-01-01

Room-temperature ionic liquids (ILs) are an emerging class of electrolytes for supercapacitors. We investigate the effects of ion size and electrode curvature on the electrical double layers (EDLs) in two ILs 1-butyl-3-methylimidazolium chloride [BMIM][Cl] and 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF(6)], using a combination of molecular dynamics (MD) and quantum density functional theory (DFT) simulations. The sizes of the counter-ion and co-ion affect the ion distribution and orientational structure of EDLs. The EDL capacitances near both planar and cylindrical electrodes were found to follow the order: [BMIM][Cl] (near the positive electrode) > [BMIM][PF(6)] (near the positive electrode) {approx} [BMIM][Cl] (near the negative electrode) {approx} [BMIM][PF(6)] (near the negative electrode). The EDL capacitance was also found to increase as the electrode curvature increases. These capacitance data can be fit to the Helmholtz model and the recently proposed exohedral electrical double-cylinder capacitor (xEDCC) model when the EDL thickness is properly parameterized, even though key features of the EDLs in ILs are not accounted for in these models. To remedy the shortcomings of existing models, we propose a 'Multiple Ion Layers with Overscreening' (MILO) model for the EDLs in ILs that takes into account two critical features of such EDLs, i.e., alternating layering of counter-ions and co-ions and charge overscreening. The capacitance computed from the MILO model agrees well with the MD prediction. Although some input parameters of the MILO model must be obtained from MD simulations, the MILO model may provide a new framework for understanding many important aspects of EDLs in ILs (e.g., the variation of EDL capacitance with the electrode potential) that are difficult to interpret using classical EDL models and experiments.

Spread and Liquidity Issues: A markets comparison

Directory of Open Access Journals (Sweden)

Strašek Sebastjan

2016-03-01

Full Text Available The financial crises are closely connected with spread changes and liquidity issues. After defining and addressing spread considerations, we research in this paper the topic of liquidity issues in times of economic crisis. We analyse the liquidity effects as recorded on spreads of securities from different markets. We stipulate that higher international risk aversion in times of financial crises coincides with widening security spreads. The paper then introduces liquidity as a risk factor into the standard value-at-risk framework, using GARCH methodology. The comparison of results of these models suggests that the size of the tested markets does not have a strong effect on the models. Thus, we find that spread analysis is an appropriate tool for analysing liquidity issues during a financial crisis.

Layering of confined water between two graphene sheets and its liquid–liquid transition

International Nuclear Information System (INIS)

Zhou Xuyan; Duan Yunrui; Wang Long; Liu Sida; Li Tao; Li Yifan; Li Hui

2017-01-01

Molecular dynamics (MD) simulations are performed to explore the layering structure and liquid–liquid transition of liquid water confined between two graphene sheets with a varied distance at different pressures. Both the size of nanoslit and pressure could cause the layering and liquid–liquid transition of the confined water. With increase of pressure and the nanoslit’s size, the confined water could have a more obvious layering. In addition, the neighboring water molecules firstly form chain structure, then will transform into square structure, and finally become triangle with increase of pressure. These results throw light on layering and liquid–liquid transition of water confined between two graphene sheets. (paper)

Mechanical design of ultraprecision weak-link stages for nanometer-scale x-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Shu, D [APS Engineering Support Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Maser, J, E-mail: shu@aps.anl.go [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439 (United States)

2009-09-01

A nanopositioning diagnostic setup has been built to support the Argonne Center for Nanoscale Materials (CNM) nanoprobe instrument commissioning process at the APS. Its laser Doppler interferometer system provides subnanometer positioning diagnostic resolution with large dynamic range. A set of original APS designed ultraprecision PZT-driven weak-link stages with high-stiffness motor-driven stages has been tested with this diagnostic setup. In this paper we present a preliminary test result of the ultraprecision weak-link stage system developed for the CNM hard x-ray nanoprobe instrument at APS sector 26. A test result for a novel laminar weak-link mechanism with sub-centimeter travel range and sub-nanometer positioning resolution is also introduced in this paper as a future work.

Liquid praseodymium heat content by levitation calorimetry. [Sample size 0. 5 - 1. 5g; 1460 to 2289/sup 0/K

Energy Technology Data Exchange (ETDEWEB)

Stretz, L.A.; Bautista, R.G.

1976-01-01

The high-temperature heat content of liquid praseodymium was measured experimentally by the levitation calorimetry technique. The samples, ranging in size from 0.5 to 1.5 g, were simultaneously levitated and heated by a radiofrequency generator in an argon-helium mixture prior to being dropped into a conventional copper block drop calorimeter. Corrections were made for the convection and radiation losses during the fall of the sample from the levitation chamber into the calorimeter. The praseodymium data, from 1460 to 2289K, were fitted by the following equation where the indicated errors represent the average deviation of the experimental value from the value predicted by the equation: H/sub T/ - H/sub 298/./sub 15/ = (41.57 +- 0.29) (T - 1208) + (41733 +- 197) J/mol. (auth)

Multilayer Laue Lens: A Path Toward One Nanometer X-Ray Focusing

International Nuclear Information System (INIS)

Yan, H.; Stephenson, G.B.; Maser, J.; Yan, H.; Conley, R.; Kang, H.C.; Stephenson, G.B.; Kang, H.C.; Maser, J.; Conley, R.; Liu, Ch.; Macrander, A.T.

2010-01-01

The multilayer Laue lens (MLL) is a novel diffractive optic for hard X-ray nano focusing, which is fabricated by thin film deposition techniques and takes advantage of the dynamical diffraction effect to achieve a high numerical aperture and efficiency. It overcomes two difficulties encountered in diffractive optics fabrication for focusing hard X-rays: (1) small outmost zone width and (2) high aspect ratio. Here, we will give a review on types, modeling approaches, properties, fabrication, and characterization methods of MLL optics. We show that a full-wave dynamical diffraction theory has been developed to describe the dynamical diffraction property of the MLL and has been employed to design the optimal shapes for nano focusing. We also show a 16 nm line focus obtained by a partial MLL and several characterization methods. Experimental results show a good agreement with the theoretical calculations. With the continuing development of MLL optics, we believe that an MLL-based hard x-ray microscope with true nanometer resolution is on the horizon

Heat Transfer Characteristics during Boiling of Immiscible Liquids Flowing in Narrow Rectangular Heated Channels

Directory of Open Access Journals (Sweden)

Yasuhisa Shinmoto

2017-11-01

Full Text Available The use of immiscible liquids for cooling of surfaces with high heat generation density is proposed based on the experimental verification of its superior cooling characteristics in fundamental systems of pool boiling and flow boiling in a tube. For the purpose of practical applications, however, heat transfer characteristics due to flow boiling in narrow rectangular channels with different small gap sizes need to be investigated. The immiscible liquids employed here are FC72 and water, and the gap size is varied as 2, 1, and 0.5 mm between parallel rectangular plates of 30 mm × 175 mm, where one plate is heated. To evaluate the effect of gap size, the heat transfer characteristics are compared at the same inlet velocity. The generation of large flattened bubbles in a narrow gap results in two opposite trends of the heat transfer enhancement due to thin liquid film evaporation and of the deterioration due to the extension of dry patch in the liquid film. The situation is the same as that observed for pure liquids. The latter negative effect is emphasized for extremely small gap sizes if the flow rate ratio of more-volatile liquid to the total is not reduced. The addition of small flow rate of less-volatile liquid can increase the critical heat flux (CHF of pure more-volatile liquid, while the surface temperature increases at the same time and assume the values between those for more-volatile and less-volatile liquids. By the selection of small flow rate ratio of more-volatile liquid, the surface temperature of pure less-volatile liquid can be decreased without reducing high CHF inherent in the less-volatile liquid employed. The trend of heat transfer characteristics for flow boiling of immiscible mixtures in narrow channels is more sensitive to the composition compared to the flow boiling in a round tube.

Ion pairing in ionic liquids

International Nuclear Information System (INIS)

Kirchner, Barbara; Malberg, Friedrich; Firaha, Dzmitry S; Hollóczki, Oldamur

2015-01-01

In the present article we briefly review the extensive discussion in literature about the presence or absence of ion pair-like aggregates in ionic liquids. While some experimental studies point towards the presence of neutral subunits in ionic liquids, many other experiments cannot confirm or even contradict their existence. Ion pairs can be detected directly in the gas phase, but no direct method is available to observe such association behavior in the liquid, and the corresponding indirect experimental proofs are based on such assumptions as unity charges at the ions. However, we have shown by calculating ionic liquid clusters of different sizes that assuming unity charges for ILs is erroneous, because a substantial charge transfer is taking place between the ionic liquid ions that reduce their total charge. Considering these effects might establish a bridge between the contradicting experimental results on this matter. Beside these results, according to molecular dynamics simulations the lifetimes of ion–ion contacts and their joint motions are far too short to verify the existence of neutral units in these materials. (topical review)

Evaluation of a contact device type ejector system for liquid-liquid extraction

International Nuclear Information System (INIS)

Schwamback, Niomedes

2002-04-01

The objective of the present work was to evaluate an ejector system, operated simultaneously with two immiscible liquid phases and a gas phase, as a contact device for liquid-liquid extraction processes. The ejector, made of perspex, has a variable geometry, although this feature was not explored in the thesis. Motivated by recent uses of liquid-liquid extraction processes for the removal of traces of heavy metal from waste waters, it was decided to carry out tests with synthetic effluents. This strategy, typical of experimental work under evaluation of technical feasibility, greatly simplifies experiments, since the nature of the chemical species involved and their feed concentrations are known exactly and do not fluctuate. The extractant used was DEHPA (diethyl hexyl phosphoric acid). The metal chosen for tests was iron with oxidation number +3, because of its high extraction coefficient towards DEHPA and also for its chemical behavior similar to americium and other heavy metals. In addition to that, iron forms soluble coloured complexes adequate to spectrophotometric determination analysis, a simple, quick and very reliable analytical technique. The effects of electrolytes of interest, namely NaCl, FeSO 4 and Al(NO 3 ) 3 , upon the extraction process were investigated. The effects resulting from the introduction of a gas phase, actually air (bubbles), in the ejector upon the extraction efficiency were studied. By coupling advanced digital photographic technique and image analysis with microcomputer, the bubble mean size was measured. It was then correlated with equipment's geometrical (characteristic diameters) and operational variables (phases' flow rates and gas hold-ups). To enable scale-up procedures, data were preferably correlated by means of dimensionless groups. For the systems and conditions investigated in this thesis and under the same operational conditions, the introduction of air bubbles by means of an ejector has greatly improved the process

COMPANY SIZE, TRADING ACTIVITY AND LIQUIDITY AS A DETERMINANTS OF CROSS-SECTIONAL MOMENTUM TRADING STRATEGY ON RUSSIAN STOCK MARKET. PART 2

Directory of Open Access Journals (Sweden)

Teplova T. V.

2014-09-01

Full Text Available Momentum-effect has many interpretations in the practice of investing and in understanding of anomalies in asset prices. We consider a Cross-Sectional momentum effects and the corresponding two medium-term (3 months or more trading strategies that are different from the trend following rules for individual assets. We tested four hypothesis deals with cross-sectional momentum effect on the Russian stock market and the possibility of building a self-financing (long-short trading strategy at three time horizon (stock market growth from 2004 until mid-2008, financial crisis and post-crisis periods. It is shown that for the Russian market cross-sectional momentum strategy with partly rebalanced portfolio maximizing portfolio return (134 stocks listed from 2004 to 2014 in the few Russian stock exchanges should be based on the three-month formation period and three-month holding period periods (3/1/3. We have identified elements of profit-maximizing momentum strategy: three time windows and determinants of assets. Monthly average return of arbitrage strategy is estimated at 1.5 % for 134 common shares. Implementation of the strategy for the post-crisis period does not allow to maximize profit. For 6 month and more investment windows it gets the advantage of reverse strategy (opening long positions in stocks with low investment results and short position for assets with high relative returns. Fundamental parameters of the issuer (size of companies like market capitalization and two measures of liquidity (trading activity and transaction costs like bid-ask spread are significant to maximize portfolio performance (we prove the growth of monthly average return ranging from 1.5 to 2.5 %. We find that size and liquidity control momentum strategy can earn positive profits in Russian stock market, larger than naïve momentum.

Structural design of liquid oxygen/liquid methane robotic lander JANUS

Science.gov (United States)

Chaidez, Mariana

As the attempt to send humans to Mars has gained momentum in the last decade, the need to find alternative propellants that are safer, less toxic, and yields a better performance has become apparent [1]. Liquid methane and oxygen have emerged as a suitable alternative. In addition, the incorporation of liquid methane/liquid oxygen into the propulsion system has demonstrated an increase in engine performance, as well as a reduction in the volume, size and complexity of the propulsion system. In an attempt to further understand the technologies that are possible to develop using liquid oxygen (LO 2) and liquid methane (LCH4), a preliminary design of a robotic lander JANUS is being completed by the Center for Space Exploration and Technology Research (cSTER). The structural design of the vehicle is important because it acts as the skeleton of the vehicle and dictates the maneuverability of the robotic lander. To develop the structure of the robotic lander, six different design vehicle concepts with varying tank configurations were considered. Finite Element Analysis (FEA) was completed on each model to optimize each vehicle. Trade studies were completed to choose the best design for JANUS. Upon completion of the trade studies the design for the first prototype of JANUS was initiated in which the tank and thrust modules were designed. This thesis will describe the design process for the structural design of the JANUS.

Energy absorption behaviors of nanoporous materials functionalized (NMF) liquids

OpenAIRE

Kim, Tae Wan

2011-01-01

For many decades, people have been actively investigating high-performance energy absorption materials, so as to develop lightweight and small-sized protective and damping devices, such as blast mitigation helmets, vehicle armors, etc. Recently, the high energy absorption efficiency of nanoporous materials functionalized (NMF) liquids has drawn considerable attention. A NMF liquid is usually a liquid suspension of nanoporous particles with large nanopore surface areas (100 - 2,000 m²/g). The ...

Size effects in olivine control strength in low-temperature plasticity regime

Science.gov (United States)

Kumamoto, K. M.; Thom, C.; Wallis, D.; Hansen, L. N.; Armstrong, D. E. J.; Goldsby, D. L.; Warren, J. M.; Wilkinson, A. J.

2017-12-01

The strength of the lithospheric mantle during deformation by low-temperature plasticity controls a range of geological phenomena, including lithospheric-scale strain localization, the evolution of friction on deep seismogenic faults, and the flexure of tectonic plates. However, constraints on the strength of olivine in this deformation regime are difficult to obtain from conventional rock-deformation experiments, and previous results vary considerably. We demonstrate via nanoindentation that the strength of olivine in the low-temperature plasticity regime is dependent on the length-scale of the test, with experiments on smaller volumes of material exhibiting larger yield stresses. This "size effect" has previously been explained in engineering materials as a result of the role of strain gradients and associated geometrically necessary dislocations in modifying plastic behavior. The Hall-Petch effect, in which a material with a small grain size exhibits a higher strength than one with a large grain size, is thought to arise from the same mechanism. The presence of a size effect resolves discrepancies among previous experimental measurements of olivine, which were either conducted using indentation methods or were conducted on polycrystalline samples with small grain sizes. An analysis of different low-temperature plasticity flow laws extrapolated to room temperature reveals a power-law relationship between length-scale (grain size for polycrystalline deformation and contact radius for indentation tests) and yield strength. This suggests that data from samples with large inherent length scales best represent the plastic strength of the coarse-grained lithospheric mantle. Additionally, the plastic deformation of nanometer- to micrometer-sized asperities on fault surfaces may control the evolution of fault roughness due to their size-dependent strength.

The Knight shift in liquid gallium confined within porous glasses and opals

International Nuclear Information System (INIS)

Charnaya, E V; Michel, D; Tien, C; Kumzerov, Yu A; Yaskov, D

2003-01-01

71 Ga nuclear magnetic resonance studies were carried out for liquid gallium embedded into porous glasses with different pore sizes and into artificial opals within the temperature range from about 320 K to complete confined gallium freezing. A general decrease in the Knight shift compared to the bulk melt depending on pore sizes was observed in contrast to theoretical predictions. Correlations between alterations in the Knight shift and pore sizes were established for particular pore geometry. It was also observed that confined geometry affects the temperature dependence of the Knight shift in liquid gallium

Fragmentation of suddenly heated liquids in ICF reactors. Revision 1

International Nuclear Information System (INIS)

Blink, J.A.; Hoover, W.G.

1985-01-01

Fragmentation of free liquids in Inertial Confinement Fusion reactors could determine the upper bound on reactor pulse rate because increased surface area will enhance the cooling and condensation of coolant ablated by the fusion x rays. Relaxation from the suddenly (neutron) heated state will move a liquid into the negative pressure region under the liquid-vapor P-V dome. The resulting expansion in a diverging geometry will hydrodynamically force the liquid to fragment, with vapor then forming from the new surfaces to fill the cavities. An energy minimization model is used to determine the fragment size that produces the least amount of non-fragment-center-of-mass energy; i.e., the sum of the surface and dilational kinetic energies. This model predicts fragmentation dependence on original system size and amount of isochoric heating as well as liquid density, Grueneisen parameter, surface tension, and sound speed. A two dimensional molecular dynamics code was developed to test the model at a microscopic scale for the Lennard-Jones fluid with its two adjustable constants chosen to represent lithium

Design of slurry bubble column reactors: novel technique for optimum catalyst size selection contractual origin of the invention

Science.gov (United States)

Gamwo, Isaac K [Murrysville, PA; Gidaspow, Dimitri [Northbrook, IL; Jung, Jonghwun [Naperville, IL

2009-11-17

A method for determining optimum catalyst particle size for a gas-solid, liquid-solid, or gas-liquid-solid fluidized bed reactor such as a slurry bubble column reactor (SBCR) for converting synthesis gas into liquid fuels considers the complete granular temperature balance based on the kinetic theory of granular flow, the effect of a volumetric mass transfer coefficient between the liquid and the gas, and the water gas shift reaction. The granular temperature of the catalyst particles representing the kinetic energy of the catalyst particles is measured and the volumetric mass transfer coefficient between the gas and liquid phases is calculated using the granular temperature. Catalyst particle size is varied from 20 .mu.m to 120 .mu.m and a maximum mass transfer coefficient corresponding to optimum liquid hydrocarbon fuel production is determined. Optimum catalyst particle size for maximum methanol production in a SBCR was determined to be in the range of 60-70 .mu.m.

Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport.

Science.gov (United States)

Sheng, Zhizhi; Wang, Honglong; Tang, Yongliang; Wang, Miao; Huang, Lizhi; Min, Lingli; Meng, Haiqiang; Chen, Songyue; Jiang, Lei; Hou, Xu

2018-02-01

The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems. Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate the sorting of a wide range of gases and liquids under a steady-state applied pressure, nearly eliminate fouling, and can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and liquid can be achieved through our gating interfacial design and the controllable pores' deformation without changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles.

Pleural liquid and its exchanges.

Science.gov (United States)

Agostoni, Emilio; Zocchi, Luciano

2007-12-15

After an account on morphological features of visceral and parietal pleura, mechanical coupling between lung and chest wall is outlined. Volume of pleural liquid is considered along with its thickness in various regions, and its composition. Pleural liquid pressure (P(liq)) and pressure exerted by lung recoil in various species and postures are then compared, and the vertical gradient of P(liq) considered. Implications of lower P(liq) in the lung zone than in the costo-phrenic sinus at iso-height are pointed out. Mesothelial permeability to H(2)O, Cl(-), Na(+), mannitol, sucrose, inulin, albumin, and various size dextrans is provided, along with paracellular "pore" radius of mesothelium. Pleural liquid is produced by filtration from parietal pleura capillaries according to Starling forces. It is removed by absorption in visceral pleura capillaries according to Starling forces (at least in some species), lymphatic drainage through stomata of parietal mesothelium (essential to remove cells, particles, and large macromolecules), solute-coupled liquid absorption, and transcytosis through mesothelium.

Sub-nanometer glass surface dynamics induced by illumination

International Nuclear Information System (INIS)

Nguyen, Duc; Nienhaus, Lea; Haasch, Richard T.; Lyding, Joseph; Gruebele, Martin

2015-01-01

Illumination is known to induce stress and morphology changes in opaque glasses. Amorphous silicon carbide (a-SiC) has a smaller bandgap than the crystal. Thus, we were able to excite with 532 nm light a 1 μm amorphous surface layer on a SiC crystal while recording time-lapse movies of glass surface dynamics by scanning tunneling microscopy (STM). Photoexcitation of the a-SiC surface layer through the transparent crystal avoids heating the STM tip. Up to 6 × 10 4 s, long movies of surface dynamics with 40 s time resolution and sub-nanometer spatial resolution were obtained. Clusters of ca. 3-5 glass forming units diameter are seen to cooperatively hop between two states at the surface. Photoexcitation with green laser light recruits immobile clusters to hop, rather than increasing the rate at which already mobile clusters hop. No significant laser heating was observed. Thus, we favor an athermal mechanism whereby electronic excitation of a-SiC directly controls glassy surface dynamics. This mechanism is supported by an exciton migration-relaxation-thermal diffusion model. Individual clusters take ∼1 h to populate states differently after the light intensity has changed. We believe the surrounding matrix rearranges slowly when it is stressed by a change in laser intensity, and clusters serve as a diagnostic. Such cluster hopping and matrix rearrangement could underlie the microscopic mechanism of photoinduced aging of opaque glasses

Liquid waste processing device

International Nuclear Information System (INIS)

Matsumoto, Kaname; Obe, Etsuji; Wakamatsu, Toshifumi.

1989-01-01

In a liquid waste processing device for processing living water wastes discharged from nuclear power plant facilities through a filtration vessel and a sampling vessel, a filtration layer disposed in the filtration vessel is divided into a plurality of layers along planes vertical to the direction of flow and the size of the filter material for each of the divided layers is made finer toward the downstream. Further, the thickness of the filtration material in each of the divided layers is also reduced toward the downstream. The filter material is packed such that the porosity in each of the divided layers is substantially identical. Further, the filtration material is packed in a mesh-like bag partitioned into a desired size and laid with no gaps to the planes vertical to the direction of the flow. Thus, liquid wastes such as living water wastes can be processed easily and simply so as to satisfy circumstantial criteria without giving undesired effects on the separation performance and life time and with easy replacement of filter. (T.M.)

Impurity effects on ionic-liquid-based supercapacitors

International Nuclear Information System (INIS)

Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

2016-01-01

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. As a result, by comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

Impurity effects on ionic-liquid-based supercapacitors

Science.gov (United States)

Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

2017-02-01

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. By comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

Numerical and experimental study of liquid breakup process in solid rocket motor nozzle

Science.gov (United States)

Yen, Yi-Hsin

Rocket propulsion is an important travel method for space exploration and national defense, rockets needs to be able to withstand wide range of operation environment and also stable and precise enough to carry sophisticated payload into orbit, those engineering requirement makes rocket becomes one of the state of the art industry. The rocket family have been classified into two major group of liquid and solid rocket based on the fuel phase of liquid or solid state. The solid rocket has the advantages of simple working mechanism, less maintenance and preparing procedure and higher storage safety, those characters of solid rocket make it becomes popular in aerospace industry. Aluminum based propellant is widely used in solid rocket motor (SRM) industry due to its avalibility, combusion performance and economical fuel option, however after aluminum react with oxidant of amonimum perchrate (AP), it will generate liquid phase alumina (Al2O3) as product in high temperature (2,700˜3,000 K) combustion chamber enviornment. The liquid phase alumina particles aggromorate inside combustion chamber into larger particle which becomes major erosion calprit on inner nozzle wall while alumina aggromorates impinge on the nozzle wall surface. The erosion mechanism result nozzle throat material removal, increase the performance optimized throat diameter and reduce nozzle exit to throat area ratio which leads to the reduction of exhaust gas velocity, Mach number and lower the propulsion thrust force. The approach to avoid particle erosion phenomenon taking place in SRM's nozzle is to reduce the alumina particle size inside combustion chamber which could be done by further breakup of the alumina droplet size in SRM's combustion chamber. The study of liquid breakup mechanism is an important means to smaller combustion chamber alumina droplet size and mitigate the erosion tack place on rocket nozzle region. In this study, a straight two phase air-water flow channel experiment is set up

Probing Local Ionic Dynamics in Functional Oxides: From Nanometer to Atomic Scale

Science.gov (United States)

Kalinin, Sergei

2014-03-01

Vacancy-mediated electrochemical reactions in oxides underpin multiple applications ranging from electroresistive memories, to chemical sensors to energy conversion systems such as fuel cells. Understanding the functionality in these systems requires probing reversible (oxygen reduction/evolution reaction) and irreversible (cathode degradation and activation, formation of conductive filaments) electrochemical processes. In this talk, I summarize recent advances in probing and controlling these transformations locally on nanometer level using scanning probe microscopy. The localized tip concentrates the electric field in the nanometer scale volume of material, inducing local transition. Measured simultaneously electromechanical response (piezoresponse) or current (conductive AFM) provides the information on the bias-induced changes in material. Here, I illustrate how these methods can be extended to study local electrochemical transformations, including vacancy dynamics in oxides such as titanates, LaxSr1-xCoO3, BiFeO3, and YxZr1-xO2. The formation of electromechanical hysteresis loops and their bias-, temperature- and environment dependences provide insight into local electrochemical mechanisms. In materials such as lanthanum-strontium cobaltite, mapping both reversible vacancy motion and vacancy ordering and static deformation is possible, and can be corroborated by post mortem STEM/EELS studies. In ceria, a broad gamut of electrochemical behaviors is observed as a function of temperature and humidity. The possible strategies for elucidation ionic motion at the electroactive interfaces in oxides using high-resolution electron microscopy and combined ex-situ and in-situ STEM-SPM studies are discussed. In the second part of the talk, probing electrochemical phenomena on in-situ grown surfaces with atomic resolution is illustrated. I present an approach based on the multivariate statistical analysis of the coordination spheres of individual atoms to reveal

Highly water-dispersible silver sulfadiazine decorated with polyvinyl pyrrolidone and its antibacterial activities

Energy Technology Data Exchange (ETDEWEB)

Li, Ping; Wu, Longlong [Key Laboratory for Special Functional Materials, Henan University, Kaifeng 475004 (China); Li, Binjie, E-mail: lbj821@163.com [Key Laboratory for Special Functional Materials, Henan University, Kaifeng 475004 (China); Medical School of Henan University, Kaifeng 475004 (China); Zhao, Yanbao [Key Laboratory for Special Functional Materials, Henan University, Kaifeng 475004 (China); Qu, Peng [Department of Chemistry, Shangqiu Normal University, Shangqiu 476000 (China)

2016-03-01

Highly water-dispersible silver sulfadiazine (SSD) was prepared by liquid phase method with polyvinyl pyrrolidone (PVP) as a surface modification agent. The structure and morphology of the PVP-modified silver sulfadiazine (P-SSD) were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier-transform infrared (FT-IR) spectrometry. The produced particles are ginkgo leaf-like architecture with the sizes of micron-nanometer. Due to hydrophilic PVP decorated on the surface, the P-SSD has excellent dispersion in water over a period of 24 h, which is obviously stable by comparison to that of the commercial silver sulfadiazine (C-SSD). In addition, the P-SSD exhibits good antibacterial activities against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). - Highlights: • Polyvinyl pyrrolidone decorated silver sulfadiazine was synthesized via a one-pot protocol. • The produced particles present ginkgo leaf-like architectures with sizes of micro-nanometer. • The resulted silver sulfadiazine has highly dispersible in water over a period of 24 h. • The obtained sliver sulfadiazine exhibits excellent antibacterial activities against E. coli, P. aeruginosa and S. aureus.

Influence of ZnO nanostructures in liquid crystal interfaces for bistable switching applications

Energy Technology Data Exchange (ETDEWEB)

Pal, Kaushik, E-mail: kaushikpal@whu.edu.cn [School of Power and Mechanical Engineering, Wuhan University, 8 East Lake South Road, Wuhan 430072 (China); Zhan, Bihong, E-mail: bihong_zhan@whu.edu.cn [School of Power and Mechanical Engineering, Wuhan University, 8 East Lake South Road, Wuhan 430072 (China); Madhu Mohan, M.L.N. [Liquid Crystal Research Laboratory (LCRL), Bannari Amman Institute of Technology, Sathyamangalam 638 401 (India); Schirhagl, Romana [University Medical Center Groningen, Department of BioMedical Engineering, Ant. Deusinglaan 1, 9713 AV Groningen (Netherlands); Wang, Guoping, E-mail: guopingwang@whu.edu.cn [School of Power and Mechanical Engineering, Wuhan University, 8 East Lake South Road, Wuhan 430072 (China)

2015-12-01

Graphical abstract: - Highlights: • One step bench top novel synthesis and growth dynamics of ZnO structures are successfully performed. • Nanostructures dispersing liquid crystals (NDLC) is recently found to have significant influence on the nucleation and growth of many functional nanocrystals (NCs), and provide a fundamental approach to modify the crystallographic phase, size, morphology, and electronic configuration of nanomaterials. • Electro-optical switching application ensures the bright field droplet design marble pattern of smectic G phase, nematic and most significant twist nematic phase pattern are obtained. • Spontaneous polarization, rotational viscosity and response time study, exploring smart applications in LCD technology. - Abstract: The controlled fabrication of nanometer-scale objects is without doubt one of the central issues in current science and technology. In this article, we exhibit a simple, one-step bench top synthesis of zinc oxide nano-tetrapods and nano-spheres which were tailored by the facial growth of nano-wires (diameter ≈ 24 nm; length ≈ 118 nm) and nano-cubes (≈395 nm edge) to nano-sphere (diameter ≈ 585 nm) appeaded. The possibilities of inexpensive, simple solvo-chemical synthesis of nanostructures were considered. In this article, a successful attempt has been made that ZnO nano-structures dispersed on well aligned hydrogen bonded liquid crystals (HBLC) comprising azelaic acid (AC) with p-n-alkyloxy benzoic acid (nBAO) by varying the respective alkyloxy carbon number (n = 5). The dispersion of nanomaterials with HBLC is an effective route to enhance the existing functionalities. A series of these composite materials were analyzed by polarizing optical microscope's electro-optical switching. An interesting feature of AC + nBAO is the inducement of tilted smectic G phase with increasing carbon chain length. Phase diagrams of the above hybrid ZnO nanomaterial influenced LC complex and pure LC were

Recent Advances in Discotic Liquid Crystal-Assisted Nanoparticles

Directory of Open Access Journals (Sweden)

Ashwathanarayana Gowda

2018-03-01

Full Text Available This article primarily summarizes recent advancement in the field of discotic liquid crystal (DLC nanocomposites. Discotic liquid crystals are nanostructured materials, usually 2 to 6 nm size and have been recognized as organic semiconducting materials. Recently, it has been observed that the dispersion of small concentration of various functionalized zero-, one- and two-dimensional nanomaterials in the supramolecular order of mesophases of DLCs imparts negligible impact on liquid crystalline properties but enhances their thermal, supramolecular and electronic properties. Synthesis, characterization and dispersion of various nanoparticles in different discotics are presented.

Fluctuations, Finite-Size Effects and the Thermodynamic Limit in Computer Simulations: Revisiting the Spatial Block Analysis Method

Directory of Open Access Journals (Sweden)

Maziar Heidari

2018-03-01

Full Text Available The spatial block analysis (SBA method has been introduced to efficiently extrapolate thermodynamic quantities from finite-size computer simulations of a large variety of physical systems. In the particular case of simple liquids and liquid mixtures, by subdividing the simulation box into blocks of increasing size and calculating volume-dependent fluctuations of the number of particles, it is possible to extrapolate the bulk isothermal compressibility and Kirkwood–Buff integrals in the thermodynamic limit. Only by explicitly including finite-size effects, ubiquitous in computer simulations, into the SBA method, the extrapolation to the thermodynamic limit can be achieved. In this review, we discuss two of these finite-size effects in the context of the SBA method due to (i the statistical ensemble and (ii the finite integration domains used in computer simulations. To illustrate the method, we consider prototypical liquids and liquid mixtures described by truncated and shifted Lennard–Jones (TSLJ potentials. Furthermore, we show some of the most recent developments of the SBA method, in particular its use to calculate chemical potentials of liquids in a wide range of density/concentration conditions.

Vapour phase motion in cryogenic systems containing superheated and subcooled liquids

Science.gov (United States)

Kirichenko, Yu. A.; Chernyakov, P. S.; Seregin, V. E.

The development of vent pipelines, and venting storage tanks for cryogenic liquids requires the knowledge of the law of motion as well as regularities of vapour content variation in the liquid and heat dissipation by the vapour phase. This is a theoretical study of the effect of superheating (subcooling) of the liquid, relative acceleration and reduced pressure upon the size and velocity of noninteracting vapour bubbles, moving in the liquid, and upon their resistance and heat transfer coefficients.

Thermodynamics of mixtures containing alkoxyethanols. XXVIII: Liquid-liquid equilibria for 2-phenoxyethanol + selected alkanes

Energy Technology Data Exchange (ETDEWEB)

Alonso, Victor; Garcia, Mario [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain); Gonzalez, Juan Antonio, E-mail: jagl@termo.uva.es [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain); Garcia De La Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain)

2011-07-10

Highlights: {yields} LLE coexistence curves were determined for mixtures of 2PhEE with alkanes. {yields} UCST values are higher for n-alkane systems than for solutions with cyclic alkanes. {yields} For the latter mixtures, UCST increases with the size of the alkyl group attached. {yields} Alkoxyethanol-alkoxyethanol interactions are enhanced by aromatic group in cellosolve. - Abstract: The coexistence curves of the liquid-liquid equilibria (LLE) for systems of 2-phenoxyethanol (2PhEE) with heptane, octane, cyclohexane, methylcyclohexane or ethylcyclohexane have been determined by the method of the critical opalescence using a laser scattering technique. All the curves show an upper critical solution temperature (UCST), have a rather horizontal top and their symmetry depends on the relative size of the mixture compounds. UCST values are higher for systems with linear alkanes than for solutions including cyclic alkanes. For these mixtures, the UCST increases with the size of the alkyl group attached to the cyclic part of the molecule. It is shown that interactions between alkoxyethanol molecules are stronger when the hydroxyether contains an aromatic group. Data are used to determine the critical exponent for the order parameter mole fraction. Values obtained are consistent with those provided by the Ising model or by the renormalization group theory.

Thermodynamics of mixtures containing alkoxyethanols. XXVIII: Liquid-liquid equilibria for 2-phenoxyethanol + selected alkanes

International Nuclear Information System (INIS)

Alonso, Victor; Garcia, Mario; Gonzalez, Juan Antonio; Garcia De La Fuente, Isaias; Cobos, Jose Carlos

2011-01-01

Highlights: → LLE coexistence curves were determined for mixtures of 2PhEE with alkanes. → UCST values are higher for n-alkane systems than for solutions with cyclic alkanes. → For the latter mixtures, UCST increases with the size of the alkyl group attached. → Alkoxyethanol-alkoxyethanol interactions are enhanced by aromatic group in cellosolve. - Abstract: The coexistence curves of the liquid-liquid equilibria (LLE) for systems of 2-phenoxyethanol (2PhEE) with heptane, octane, cyclohexane, methylcyclohexane or ethylcyclohexane have been determined by the method of the critical opalescence using a laser scattering technique. All the curves show an upper critical solution temperature (UCST), have a rather horizontal top and their symmetry depends on the relative size of the mixture compounds. UCST values are higher for systems with linear alkanes than for solutions including cyclic alkanes. For these mixtures, the UCST increases with the size of the alkyl group attached to the cyclic part of the molecule. It is shown that interactions between alkoxyethanol molecules are stronger when the hydroxyether contains an aromatic group. Data are used to determine the critical exponent for the order parameter mole fraction. Values obtained are consistent with those provided by the Ising model or by the renormalization group theory.

Comparing two tetraalkylammonium ionic liquids. I. Liquid phase structure

Energy Technology Data Exchange (ETDEWEB)

Lima, Thamires A.; Paschoal, Vitor H.; Faria, Luiz F. O.; Ribeiro, Mauro C. C., E-mail: mccribei@iq.usp.br [Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP (Brazil); Giles, Carlos [Departamento de Física da Matéria Condensada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP (Brazil)

2016-06-14

X-ray scattering experiments at room temperature were performed for the ionic liquids n-butyl-trimethylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1114}][NTf{sub 2}], and methyl-tributylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1444}][NTf{sub 2}]. The peak in the diffraction data characteristic of charge ordering in [N{sub 1444}][NTf{sub 2}] is shifted to longer distances in comparison to [N{sub 1114}][NTf{sub 2}], but the peak characteristic of short-range correlations is shifted in [N{sub 1444}][NTf{sub 2}] to shorter distances. Molecular dynamics (MD) simulations were performed for these ionic liquids using force fields available from the literature, although with new sets of partial charges for [N{sub 1114}]{sup +} and [N{sub 1444}]{sup +} proposed in this work. The shifting of charge and adjacency peaks to opposite directions in these ionic liquids was found in the static structure factor, S(k), calculated by MD simulations. Despite differences in cation sizes, the MD simulations unravel that anions are allowed as close to [N{sub 1444}]{sup +} as to [N{sub 1114}]{sup +} because anions are located in between the angle formed by the butyl chains. The more asymmetric molecular structure of the [N{sub 1114}]{sup +} cation implies differences in partial structure factors calculated for atoms belonging to polar or non-polar parts of [N{sub 1114}][NTf{sub 2}], whereas polar and non-polar structure factors are essentially the same in [N{sub 1444}][NTf{sub 2}]. Results of this work shed light on controversies in the literature on the liquid structure of tetraalkylammonium based ionic liquids.

The investigations of nanoclusters and micron-sized periodic structures created at the surface of the crystal and amorphous silica by resonant CO2 laser irradiation

Directory of Open Access Journals (Sweden)

Mukhamedgalieva A.F.

2017-01-01

Full Text Available The creation of nanoclasters and micrometer sized periodical structures at the surface of silica (crystal quartz and fused quartz by action of pulsed CO2 laser radiation (pulse energy of 1 J, pulse time of 70 ns have been investigated. The laser action on the surface of samples lead to appearance of two kind of structures – periodical micron-sized structures with the period length close to wave length of CO2 laser irradiation and nanoclusters with size close to 50-100 nanometers. This creation connects with the intensive ablation of matter at the maxima of standing waves which are a results of the interference of falling and surfaces waves. This connects with the resonant absorption of infrared laser radiation by silicate minerals.

Bank Liquidity and Financial Performance: Evidence from Moroccan Banking Industry

Directory of Open Access Journals (Sweden)

El Mehdi Ferrouhi

2014-12-01

Full Text Available This paper aims to analyze the relationship between liquidity risk and financial performance of Moroccan banks and to define the determinants of bank’s performance in Morocco during the period 2001–2012. We first evaluate Moroccan banks’ liquidity positions through different liquidity and performance ratios then we apply a panel date regression to identify determinants of Moroccan banks performance. We use 4 bank’s performance ratios, 6 liquidity ratios and we analyze 5 specific determinants and 5 macroeconomic determinants of bank performance. Results show that Moroccan bank’s performance is mainly determined by 7 determinants: liquidity ratio, size of banks, logarithm of the total assets squared, external funding to total liabilities, share of own bank’s capital of the bank’s total assets, foreign direct investments, unemployment rate and the realization of the financial crisis variable. Banks’ performance depends positively on size of banks, on foreign direct investments and on the realization of the financial crisis and negatively on external funding to total liabilities, on share of own bank’s capital of the bank’s total assets and on unemployment rate while the dependence between bank performance and liquidity ratios and bank performance and logarithm of the total assets squared depend on the model used.

Transport of Liquid Phase Organic Solutes in Liquid Crystalline Membranes

OpenAIRE

Han, Sangil

2010-01-01

Porous cellulose nitrate membranes were impregnated with 8CB and PCH5 LCs (liquid crystals) and separations of solutes dissolved in aqueous phases were performed while monitoring solute concentration via UV-VIS spectrometry. The diffusing organic solutes, which consist of one aromatic ring and various functional groups, were selected to exclude molecular size effects on the diffusion and sorption. We studied the effects on solute transport of solute intra-molecular hydrogen bonding and so...

Liquid-liquid extraction. Choice, calculation and design of devices

International Nuclear Information System (INIS)

Leybros, J.

2005-01-01

The aim of this work is to study the problematic due to the choice of an equipment, to its size and to its industrial bringing into operation. Besides its efficiency to carry out a mass transfer, the economical interest of an industrial device will be proportional to its specific rate (volume treated by surface unit of the cross section of the extractor). Nevertheless, as it seems to be logic to maximize the three parameters which have an influence on it (transfer coefficient, interfacial surface and transfer potential), there exists no device which can modify separately any of these parameters. In order to satisfy these aims, a great diversity of devices have been put on the market. Indeed, it exists about twenty different industrial devices. This diversity leads the engineer, during the design of a solvent extraction device, to take difficult and subjective decisions without pilot experiment on the considered system. The main problem of an economical and optimized calculation of the liquid-liquid extractors from theoretical data has still not found totally satisfying solutions. Thus, except in some cases where we have empirical correlations, the recourse to prototype experiments is required and the most recent advances have resulted essentially to define more reliable rules for the extrapolation of these experiments for the size of industrial devices. (O.M.)

Parameterizing Size Distribution in Ice Clouds

Energy Technology Data Exchange (ETDEWEB)

DeSlover, Daniel; Mitchell, David L.

2009-09-25

PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the “small mode”. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice

Polarized View of Supercooled Liquid Water Clouds

Science.gov (United States)

Alexandrov, Mikhail D.; Cairns, Brian; Van Diedenhoven, Bastiaan; Ackerman, Andrew S.; Wasilewski, Andrzej P.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Platnick, Steven E.; Arnold, G. Thomas

2016-01-01

Supercooled liquid water (SLW) clouds, where liquid droplets exist at temperatures below 0 C present a well known aviation hazard through aircraft icing, in which SLW accretes on the airframe. SLW clouds are common over the Southern Ocean, and climate-induced changes in their occurrence is thought to constitute a strong cloud feedback on global climate. The two recent NASA field campaigns POlarimeter Definition EXperiment (PODEX, based in Palmdale, California, January-February 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, based in Houston, Texas in August- September 2013) provided a unique opportunity to observe SLW clouds from the high-altitude airborne platform of NASA's ER-2 aircraft. We present an analysis of measurements made by the Research Scanning Polarimeter (RSP) during these experiments accompanied by correlative retrievals from other sensors. The RSP measures both polarized and total reflectance in 9 spectral channels with wavelengths ranging from 410 to 2250 nm. It is a scanning sensor taking samples at 0.8deg intervals within 60deg from nadir in both forward and backward directions. This unique angular resolution allows for characterization of liquid water droplet size using the rainbow structure observed in the polarized reflectances in the scattering angle range between 135deg and 165deg. Simple parametric fitting algorithms applied to the polarized reflectance provide retrievals of the droplet effective radius and variance assuming a prescribed size distribution shape (gamma distribution). In addition to this, we use a non-parametric method, Rainbow Fourier Transform (RFT),which allows retrieval of the droplet size distribution without assuming a size distribution shape. We present an overview of the RSP campaign datasets available from the NASA GISS website, as well as two detailed examples of the retrievals. In these case studies we focus on cloud fields with spatial features

Nonmonotonic behaviour of superconducting critical temperature of Nb/CuNi bilayers with a nanometer range of layer thickness

International Nuclear Information System (INIS)

Morari, R.; Antropov, E.; Socrovisciuc, A.; Prepelitsa, A.; Zdravkov, V.I.; Tagirov, L.R.; Kupriyanov, M.Yu.; Sidorenko, A.S.

2009-01-01

Present work reports the result of the proximity effect investigation for superconducting Nb/CuNi-bilayers with the thickness of the ferromagnetic layer (Cu x Ni 1-x ) being in the sub-nanometer range. It was found a non-monotonic behavior of the critical temperature T c , i.e. its growth with the increasing of the ferromagnetic layer thickness dF, for the series of the samples with constant thickness of Nb layer, (d Nb = const). (authors)

Size-exclusion chromatography using core-shell particles.

Science.gov (United States)

Pirok, Bob W J; Breuer, Pascal; Hoppe, Serafine J M; Chitty, Mike; Welch, Emmet; Farkas, Tivadar; van der Wal, Sjoerd; Peters, Ron; Schoenmakers, Peter J

2017-02-24

Size-exclusion chromatography (SEC) is an indispensable technique for the separation of high-molecular-weight analytes and for determining molar-mass distributions. The potential application of SEC as second-dimension separation in comprehensive two-dimensional liquid chromatography demands very short analysis times. Liquid chromatography benefits from the advent of highly efficient core-shell packing materials, but because of the reduced total pore volume these materials have so far not been explored in SEC. The feasibility of using core-shell particles in SEC has been investigated and contemporary core-shell materials were compared with conventional packing materials for SEC. Columns packed with very small core-shell particles showed excellent resolution in specific molar-mass ranges, depending on the pore size. The analysis times were about an order of magnitude shorter than what could be achieved using conventional SEC columns. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamics of bubble formation in highly viscous liquids.

Science.gov (United States)

Pancholi, Ketan; Stride, Eleanor; Edirisinghe, Mohan

2008-04-15

There has recently been considerable interest in the development of devices for the preparation of monodisperse microbubble suspensions for use as ultrasound contrast agents and drug delivery vehicles. These applications require not only a high degree of bubble uniformity but also a maximum bubble size of 8 mum, and this provides a strong motivation for developing an improved understanding of the process of bubble formation in a given device. The aim of this work was to investigate bubble formation in a T-junction device and determine the influence of the different processing parameters upon bubble size, in particular, liquid viscosity. Images of air bubble formation in a specially designed T-junction were recorded using a high-speed camera for different ratios of liquid to gas flow rate (Ql/Qg) and different liquid viscosities (microl). It was found that theoretical predictions of the flow profile in the focal region based on analysis of axisymmetric Stokes flow were accurate to within 6% when compared with the experimental data, indicating that this provided a suitable means of describing the bubble formation process. Both the theoretical and experimental results showed that Ql/Qg and mul had a significant influence upon bubble formation and eventual size, with higher flow rates and higher viscosities producing smaller bubbles. There were, however, found to be limiting values of Ql/Qg and mul beyond which no further reduction in bubble size was achieved.

Graphene-Based Flexible Micrometer-Sized Microbial Fuel Cell

KAUST Repository

Mink, Justine E.; Qaisi, Ramy M.; Hussain, Muhammad Mustafa

2013-01-01

Microbial fuel cells harvest electrical energy produced by bacteria during the natural decomposition of organic matter. We report a micrometer-sized microbial fuel cell that is able to generate nanowatt-scale power from microliters of liquids

Applications and limitations of electron correlation microscopy to study relaxation dynamics in supercooled liquids

Energy Technology Data Exchange (ETDEWEB)

Zhang, Pei; He, Li [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706 (United States); Besser, Matthew F. [Materials Science and Engineering, Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Liu, Ze; Schroers, Jan [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06511 (United States); Kramer, Matthew J. [Materials Science and Engineering, Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Voyles, Paul M., E-mail: paul.voyles@wisc.edu [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2017-07-15

Electron correlation microscopy (ECM) is a way to measure structural relaxation times, τ, of liquids with nanometer-scale spatial resolution using coherent electron scattering equivalent of photon correlation spectroscopy. We have applied ECM with a 3.5 nm diameter probe to Pt{sub 57.5}Cu{sub 14.7}Ni{sub 5.3}P{sub 22.5} amorphous nanorods and Pd{sub 40}Ni{sub 40}P{sub 20} bulk metallic glass (BMG) heated inside the STEM into the supercooled liquid region. These data demonstrate that the ECM technique is limited by the characteristics of the time series, which must be at least 40τ to obtain a well-converged correlation function g{sub 2}(t), and the time per frame, which must be less than 0.1τ to obtain sufficient sampling. A high-speed direct electron camera enables fast acquisition and affords reliable g{sub 2}(t) data even with low signal per frame. - Highlights: • Electron Correlation Microscopy (ECM) technique was applied to measure structural relaxation times of supercooled liquids in metallic glass. • In Pt{sub 57.5}Cu{sub 14.7}Ni{sub 5.3}P{sub 22.5} nanowire, τ and β decreases over the measured supercooled liquid regime. • In Pd{sub 40}Ni{sub 40}P{sub 20} bulk alloy, τ decreases from T{sub g}+28 °C to T{sub g}+48 °C, then increases as the temperature approaches T{sub x}. • ECM experiment requires a length of time series at least 40 times the characteristic relaxation time and a time per diffraction pattern at most 0.1 times the relaxation time.

Two-dimensional time-resolved X-ray diffraction study of liquid/solid fraction and solid particle size in Fe-C binary system with an electrostatic levitator furnace

International Nuclear Information System (INIS)

Yonemura, M; Okada, J; Ishikawa, T; Nanao, S; Watanabe, Y; Shobu, T; Toyokawa, H

2013-01-01

Liquid state provides functions such as matter transport or a reaction field and plays an important role in manufacturing processes such as refining, forging or welding. However, experimental procedures are significantly difficult for an observation of solidification process of iron and iron-based alloys in order to identify rapid transformations subjected to fast temperature evolution. Therefore, in order to study the solidification in iron and iron-based alloys, we considered a combination of high energy X-ray diffraction measurements and an electrostatic levitation method (ESL). In order to analyze the liquid/solid fraction, the solidification of melted spherical specimens was measured at a time resolution of 0.1 seconds during rapid cooling using the two-dimensional time-resolved X-ray diffraction. Furthermore, the observation of particle sizes and phase identification was performed on a trial basis using X-ray small angle scattering with X-ray diffraction.

Accelerating solidification process simulation for large-sized system of liquid metal atoms using GPU with CUDA

Energy Technology Data Exchange (ETDEWEB)

Jie, Liang [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China); Li, KenLi, E-mail: lkl@hnu.edu.cn [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China); National Supercomputing Center in Changsha, 410082 (China); Shi, Lin [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China); Liu, RangSu [School of Physics and Micro Electronic, Hunan University, Changshang, 410082 (China); Mei, Jing [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China)

2014-01-15

Molecular dynamics simulation is a powerful tool to simulate and analyze complex physical processes and phenomena at atomic characteristic for predicting the natural time-evolution of a system of atoms. Precise simulation of physical processes has strong requirements both in the simulation size and computing timescale. Therefore, finding available computing resources is crucial to accelerate computation. However, a tremendous computational resource (GPGPU) are recently being utilized for general purpose computing due to its high performance of floating-point arithmetic operation, wide memory bandwidth and enhanced programmability. As for the most time-consuming component in MD simulation calculation during the case of studying liquid metal solidification processes, this paper presents a fine-grained spatial decomposition method to accelerate the computation of update of neighbor lists and interaction force calculation by take advantage of modern graphics processors units (GPU), enlarging the scale of the simulation system to a simulation system involving 10 000 000 atoms. In addition, a number of evaluations and tests, ranging from executions on different precision enabled-CUDA versions, over various types of GPU (NVIDIA 480GTX, 580GTX and M2050) to CPU clusters with different number of CPU cores are discussed. The experimental results demonstrate that GPU-based calculations are typically 9∼11 times faster than the corresponding sequential execution and approximately 1.5∼2 times faster than 16 CPU cores clusters implementations. On the basis of the simulated results, the comparisons between the theoretical results and the experimental ones are executed, and the good agreement between the two and more complete and larger cluster structures in the actual macroscopic materials are observed. Moreover, different nucleation and evolution mechanism of nano-clusters and nano-crystals formed in the processes of metal solidification is observed with large-sized

Disintegration of liquid sheets

Science.gov (United States)

Mansour, Adel; Chigier, Norman

1990-01-01

The development, stability, and disintegration of liquid sheets issuing from a two-dimensional air-assisted nozzle is studied. Detailed measurements of mean drop size and velocity are made using a phase Doppler particle analyzer. Without air flow the liquid sheet converges toward the axis as a result of surface tension forces. With airflow a quasi-two-dimensional expanding spray is formed. The air flow causes small variations in sheet thickness to develop into major disturbances with the result that disruption starts before the formation of the main break-up region. In the two-dimensional variable geometry air-blast atomizer, it is shown that the air flow is responsible for the formation of large, ordered, and small chaotic 'cell' structures.

Wollastonite Carbonation in Water-Bearing Supercritical CO2: Effects of Particle Size.

Science.gov (United States)

Min, Yujia; Li, Qingyun; Voltolini, Marco; Kneafsey, Timothy; Jun, Young-Shin

2017-11-07

The performance of geologic CO 2 sequestration (GCS) can be affected by CO 2 mineralization and changes in the permeability of geologic formations resulting from interactions between water-bearing supercritical CO 2 (scCO 2 ) and silicates in reservoir rocks. However, without an understanding of the size effects, the findings in previous studies using nanometer- or micrometer-size particles cannot be applied to the bulk rock in field sites. In this study, we report the effects of particle sizes on the carbonation of wollastonite (CaSiO 3 ) at 60 °C and 100 bar in water-bearing scCO 2 . After normalization by the surface area, the thickness of the reacted wollastonite layer on the surfaces was independent of particle sizes. After 20 h, the reaction was not controlled by the kinetics of surface reactions but by the diffusion of water-bearing scCO 2 across the product layer on wollastonite surfaces. Among the products of reaction, amorphous silica, rather than calcite, covered the wollastonite surface and acted as a diffusion barrier to water-bearing scCO 2 . The product layer was not highly porous, with a specific surface area 10 times smaller than that of the altered amorphous silica formed at the wollastonite surface in aqueous solution. These findings can help us evaluate the impacts of mineral carbonation in water-bearing scCO 2 .

Industrial Implementation of Environmentally Friendly Nanometal Electroplating Process for Chromium and Copper Beryllium Replacement using Low Cost Pulse Current Power Supplies

Science.gov (United States)

2014-09-10

FINAL REPORT Industrial Implementation of Environmentally Friendly Nanometal Electroplating Process for Chromium and Copper Beryllium...35 3.2 Phase II – Development/Verification that Nanotechnology Based Electroplating Process to Replace EHC/Cu-Be Processes are Compatible With...36 3.3 Phase III – Development of 200kW Power Supply and Compatible Nanostructured Electroplating Processed for Commercialization

Design and synthesis of guest-host nanostructures to enhance ionic conductivity across nanocomposite membranes

Science.gov (United States)

Hu, Michael Z [Knoxville, TN; Kosacki, Igor [Oak Ridge, TN

2010-01-05

An ion conducting membrane has a matrix including an ordered array of hollow channels and a nanocrystalline electrolyte contained within at least some or all of the channels. The channels have opposed open ends, and a channel width of 1000 nanometers or less, preferably 60 nanometers or less, and most preferably 10 nanometers or less. The channels may be aligned perpendicular to the matrix surface, and the length of the channels may be 10 nanometers to 1000 micrometers. The electrolyte has grain sizes of 100 nanometers or less, and preferably grain sizes of 1 to 50 nanometers. The electrolyte may include grains with a part of the grain boundaries aligned with inner walls of the channels to form a straight oriented grain-wall interface or the electrolyte may be a single crystal. In one form, the electrolyte conducts oxygen ions, the matrix is silica, and the electrolyte is yttrium doped zirconia.

Shape distortion and dimensional precision in tungsten heavy alloy liquid phase sintering

International Nuclear Information System (INIS)

Wuwen Yi; German, R.M.; Lu, P.K.

2001-01-01

Microstructure effects on densification and shape distortion in liquid phase sintering of tungsten heavy alloy were investigated. Microstructure parameters such as the solid volume fraction, dihedral angle, initial porosity, and pore size were varied to measure densification and distortion behavior during LPS using W-Ni-Cu alloys. Green compacts were formed using ethylene-bis-stearamide as a pore-forming agent with the amount of polymer controlling the initial porosity. Different initial pore sizes were generated by varying the polymer particle size. Dihedral angle was varied by changing the Ni:Cu ratio in the alloys. Finally, the solid volume fraction was adjusted via the tungsten content. Distortion was quantified using profiles determined with a coordinate measuring machine to calculate a distortion parameter. Sintering results showed that solid volume fraction and dihedral angle are the dominant factors on densification and distortion during liquid phase sintering. Distortion decreases with increasing solid volume fraction and dihedral angle, while initial porosity and pore size have no observable effect on distortion at nearly full densification. Various strategies emerge to improve distortion control in liquid phase sintering. (author)

In vivo MR imaging of nanometer magnetically labeled bone marrow stromal cells transplanted via portal vein in rat liver

International Nuclear Information System (INIS)

Wang Ping; Wang Jianhua; Yan Zhiping; Hu Meiyu; Xu Pengju; Zhou Meiling; Ya Fuhua; Fan Sheung-tat; Luk John-m

2006-01-01

Objective: To evaluate in vivo magnetic resonance imaging with a conventional 1.5-T system for tracking of intra-portal vein transplantation nanometer magnetically labeled BMSCs in rat liver. Methods: BMSCs were isolated from 5 SD rats bone marrow with the density gradient centrifugation method. Then BMSCs were labeled with nanometer superpara-magnetic iron oxide and transfection agent. Cell labeling efficiency was assessed with determination of the percentage of Peris Prussian blue stain. Then BMSCs transplanted into normal rats' livers via portal vein. The receipts were divided into 5 groups ,including sham control,2 h ,3 d,7 d and 2 w after transplantation. Follow-up serial T 1 WI,T 2 WI and T 2 * -weighted gradient- echo MR imaging were performed at 1.5 T MRI system. MR imaging findings were compared with histology. Results: Cell labeling efficiency was more than 95% by Perls Prussian blue stain. After transplantation of labeled BMSCs via portal vein, liver's had diffuse granular signal intensity appearance in T 2 * WI MRI. Cells were detected for up to 2 w in receipts' liver's. At histologic analysis, signal intensity loss correlated with iron-loaded cells. Conclusion: MR imaging could aid in monitoring of magnetically labeled BMSCs administered via portal vein in vivo. (authors)

Study of shale reservoir nanometer-sized pores in Member 1 of Shahejie Formation in JX area, Liaozhong sag

Science.gov (United States)

Cheng, Yong; Zhang, Yu; Wen, Yiming

2018-02-01

The microscopic pore structure is the key of the shale reservoir study; however, traditional Scanning Electron Microscopy (SEM) methods cannot identify the irregular morphology caused by mechanical polishing. In this work, Scanning Electron Microscopy combined argon ion polishing technology was taken to study the characteristics of shale reservoir pores of Member 1 of Shahejie Formation (E3s1) located in JX1-1 area of Liaozhong Sag. The results show that pores between clay platelets, intraplatelet pores within clay aggregates and organic-matter pores are very rich in the area and with good pore connectivity, so these types of pores are of great significance for oil-gas exporation. Pores between clay platelets are formed by directional or semi-directional contact between edge and surface, edge and edge or surface and surface of laminated clay minerals, whose shapes are linear, mesh, and irregular with the size of 500 nm to 5 μm. The intraplatelet pores within clay aggregates are formed in the process of the transformation and compaction of clay minerals, whose shapes are usually linear with the width of 30 to 500 nm and the length of 2 to 50 μm. The organic-matter pores are from the process of the conversion from organic matters to the hydrocarbon under thermal evolution, whose shapes are gneissic, irregular, pitted and elliptical with the size of 100 nm to 2 μm. This study is of certain guiding significance to selecting target zones, evaluating resource potential and exploring & developing of shale gas in this region.

Cell size, genome size and the dominance of Angiosperms

Science.gov (United States)

Simonin, K. A.; Roddy, A. B.

2016-12-01

Angiosperms are capable of maintaining the highest rates of photosynthetic gas exchange of all land plants. High rates of photosynthesis depends mechanistically both on efficiently transporting water to the sites of evaporation in the leaf and on regulating the loss of that water to the atmosphere as CO2 diffuses into the leaf. Angiosperm leaves are unique in their ability to sustain high fluxes of liquid and vapor phase water transport due to high vein densities and numerous, small stomata. Despite the ubiquity of studies characterizing the anatomical and physiological adaptations that enable angiosperms to maintain high rates of photosynthesis, the underlying mechanism explaining why they have been able to develop such high leaf vein densities, and such small and abundant stomata, is still incomplete. Here we ask whether the scaling of genome size and cell size places a fundamental constraint on the photosynthetic metabolism of land plants, and whether genome downsizing among the angiosperms directly contributed to their greater potential and realized primary productivity relative to the other major groups of terrestrial plants. Using previously published data we show that a single relationship can predict guard cell size from genome size across the major groups of terrestrial land plants (e.g. angiosperms, conifers, cycads and ferns). Similarly, a strong positive correlation exists between genome size and both stomatal density and vein density that together ultimately constrains maximum potential (gs, max) and operational stomatal conductance (gs, op). Further the difference in the slopes describing the covariation between genome size and both gs, max and gs, op suggests that genome downsizing brings gs, op closer to gs, max. Taken together the data presented here suggests that the smaller genomes of angiosperms allow their final cell sizes to vary more widely and respond more directly to environmental conditions and in doing so bring operational photosynthetic

Enzymatic Degradation of Dynasan 114 SLN - Effect of Surfactants and Particle Size

International Nuclear Information System (INIS)

Olbrich, Carsten; Kayser, Oliver; Mueller, Rainer Helmut