9,785 research outputs found
Obscured clusters. II. GLIMPSE-C02 - A new metal rich globular cluster in the Milky Way
The estimated total number of Milky Way globulars is 160+-20. The question of
whether there are any more undiscovered globular clusters in the Milky Way is
particularly relevant with advances in near and mid-IR instrumentation. This
investigation is a part of a long-term project to search the inner Milky Way
for hidden star clusters and to study them in detail. GLIMPSE-C02 (G02) is one
of these objects, situated near the Galactic plane (l=14.129deg, b=-0.644deg).
Our analysis is based on SOFI/NTT JHKs imaging and low resolution (R~1400)
spectroscopy of three bright cluster red giants in the K atmospheric window. We
derived the metal abundance by analysis of these spectra and from the slope of
the RGB. The cluster is deeply embedded in dust and undergoes a mean reddening
of Av~24.8+-3 mag. The distance to the object is D=4.6+-0.7kpc. The metal
abundance of G02 is [Fe/H](H96)=-0.33+-0.14 and [Fe/H](CG)=-0.16+-0.12 using
different scales. The best fit to the radial surface brightness profile with a
single-mass King's model yields a core radius rc=0.70 arcmin (0.9pc), tidal
radius rt=15 arcmin (20pc), and central oncentration c=1.33. We demonstrate
that G02 is new Milky Way globular cluster, among the most metal rich globular
clusters in the Galaxy. The object is physically located at the inner edge of
the thin disk and the transition region with the bulge, and also falls in the
zone of the "missing" globulars toward the central region of the Milky Way.Comment: 5 pages, 6 figures, accepted for publication in Astronomy and
Astrophysic
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Molecular dynamics simulation of plane poiseuille flow in nanochannels
This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.This paper presents new techniques and results of simulating microflows in plane channels by the molecular dynamics (MD) method. Mass forces and thermostat are not used in these techniques. The flows are simulated by both hard-sphere molecules and molecules with the Lennard-Jones intermolecular potential. Flow at a given fluid flow rate is implemented. In this case, the initial shock profile is transformed to a parabolic type profile. However, unlike in ordinary Poiseuille flows, a slip effect is recorded on the channel walls. It is shown that, in a nanochannel, a linear pressure gradient occurs. Fluid structuring is studied. The effects of fluid density, accommodation coefficients, and channel dimensions on flow properties are investigated.This work was supported in part by the Russian Foundation for Basic Researches (grant No. 07-08-00164) and by the grant of
the President of the Russian Federation for
Support of Leading Scientific Schools (project no. NSh-454.2008.1)
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Self-diffusion and viscosity coefficient of fluids in nanochannels
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Fluid viscosity and molecular diffusion in nanochannels were studied by molecular dynamics simulation. Transport processes in a plane channel, a channel of rectangular cross-section, and in porous media were investigated. The channel height was varied from 2 to 50 nm. The interaction between molecules was simulated using the hard sphere (HS) and the Lennard-Jones (LJ) intermolecular potentials. The porous matrix was modeled by cubic packing of spheres of the same radius, and the packing density and the grain size were varied. The dependence of the transport coefficients on the fluid density and channel characteristics (channel height, channel aspect ratio, porosity of the porous medium, accommodation coefficients, etc.) was investigated.Russian Foundation for Basic Research (Grant
No. 10-01-00074) and the Federal Special
Program âScientific and scientific-pedagogical personnel of innovative Russia in 2009-2013â (projects No. P230 and No. 14.740.11.0579, No. 14.740.11.0103)
Variance fluctuations in nonstationary time series: a comparative study of music genres
An important problem in physics concerns the analysis of audio time series
generated by transduced acoustic phenomena. Here, we develop a new method to
quantify the scaling properties of the local variance of nonstationary time
series. We apply this technique to analyze audio signals obtained from selected
genres of music. We find quantitative differences in the correlation properties
of high art music, popular music, and dance music. We discuss the relevance of
these objective findings in relation to the subjective experience of music.Comment: 13 pages, 4 fig
Electron wave functions on in a static magnetic field of arbitrary direction
A basis set expansion is performed to find the eigenvalues and wave functions
for an electron on a toroidal surface subject to a constant magnetic
field in an arbitrary direction. The evolution of several low-lying states as a
function of field strength and field orientation is reported, and a procedure
to extend the results to include two-body Coulomb matrix elements on is
presented.Comment: 18 pages, 6 figure
Inventions of Scientists, Engineers and Specialists From Different Countries in the Area of Nanotechnologies. Part II
The article provides an abstract review of patents. The results of creative activity of scientists, engineers and specialists, including inventions in the field of nanotechnology and nanomaterials, being implemented, allow achieving a significant effect in construction, housing and community services, and related sectors of the economy. For example, the invention «Method for liquidphase synthesis of nanostructured ceramic material in the CeO2âSm2O3 system to create a solid oxide fuel cell» can contribute to the active development of alternative, hydrogen energy. Fuel cells have a wide range of applications â from batteries in portable electronic devices to large-scale power generation and autonomous use (for example, in remote areas). Power plants based on fuel cells are almost twice as economical as traditional ones. Their efficiency can reach 85%, and the amount of harmful emissions is almost 100 times lower due to the lack of direct chemical contact of the fuel with the oxidizer. The specialists can also be interested in the following inventions in the area of nanotechnologies: method of increasing the tensile strength of fiber composites by means of preliminary modification of carbon fibers with carbon nanotubes and molecules containing amino groups; preparation method of pure silver nanowires; towards safe and sustainable innovation in nanotechnology; method of distribution of carbon-based nanoparticles in the production of nanocomposite unidirectional thermoplastic tapes; device for reducing the impact of vibration and shock effects on the performance of technological equipment; high-density three-dimensional electrically conductive micro- and mesoporous material based on carbon nanotubes and / or low-layer graphenes and a method for its preparation; nanotechnology as a viable alternative for the removal of antimicrobial resistance determinants from discharged municipal effluents and associated watersheds; and others
Spontaneous breaking of superconformal invariance in (2+1)D supersymmetric Chern-Simons-matter theories in the large N limit
In this work it is studied the spontaneous breaking of superconformal and
gauge invariances in the Abelian N=1,2 three-dimensional supersymmetric
Chern-Simons-matter theories in a large N limit. It is computed the K\"ahlerian
effective superpotential at subleading order and shown that the
Coleman-Weinberg mechanism is the responsible for the dynamical generation of a
mass scale in the N=1 model. This effect appears due to two-loop diagrams that
are logarithmic divergent. In particular, the Coleman-Weinberg mechanism fails
when we lift the N=1 to N=2 Supersymmetric Chern-Simons-Matter model, like what
happens in a perturbative expansion in the coupling constants.Comment: 10 pages, 2 figures, PLB versio
Inventions in the Area of Nanomaterials and Nanotechnologies. Part II
Introduction. Advanced technologies impress peopleâs imagination demonstrating the latest achievements (materials, methods, systems, technologies, devices etc.) that dramatically change the world. This, first of all, concerns nanotechnological inventions designed by scientists, engineers and specialists from different countries. Main part. The article provides an abstract overview of inventions of scientists, engineers and specialists from different countries: Germany, Russia, USA, et al. The results of the creative activity of scientists, engineers and specialists, including inventions in the field of nanotechnology and nanomaterials allow, when introduced to industry, achieving a significant effect in construction, housing and communal services, and related sectors of the economy. For example, the task resolved by the invention «A composition on the basis of oxide nanostructures to provide surface with superhydrophobic properties», means to design a new method of obtaining materials with superhydrophobic properties which possess improved performance and functional characteristics which can be applied in various areas: power engineering, electronics, machine-building, construction, ship-building, aviation, aerospace and food industries. The feature of the invention is that the surfaces demonstrate superhydrophobic properties and, as a result of that, their applying allows protecting metal structures, such as power lines, frame structures, roofs, from ice formation and dirtying. The technical result is possible due to the use of composition on the basis of oxide nanostructures to provide surface with superhydrophobic properties. The composition contains tetraethoxysilane and tetraisopropyl titanate as structure-forming agents, hexamethyldisilazane as hydrophobic element, isopropyl alcohol as dissolvent, non-spheric nanocrystal titanium dioxide with particle size from 10 to 50 nm as a grow accelerator of anisotropic structures to provide specified roughness of the surface. The specialist can be also interested in the following inventions in the area of nanotechnologies: a composite heat-conducting material on the basis of nanoliquid, a nanocomposite material on the basis of potassium titanate, a method of obtaining of nanodispersed powders, hybrid supercondenser on the basis of nanosized nickel hydroxide, etc. Conclusion. One of the most challenging tasks the economy of every country faces is to increase industrial competitiveness through technological upgrade. From the side of the state and companies the principal object to control in this process are the people and enterprises dealing with introduction of inventions and new technologie
Inventions of Scientists, Engineers and Specialists from Different Countries in the Area of Nanotechnologies. Part IV
Introduction. Advanced technologies impress people\u27s imagination demonstrating the latest achievements (materials, methods, systems, technologies, devices etc.) that dramatically change the world. This, first of all, concerns nanotechnological inventions designed by scientists, engineers and specialists from different countries. Main part. The paper briefly reviews inventions made by scientists, engineers and specialists from different countries: Russia, USA, China, Belarus, Great Britain, Vietnam, Denmark, the Kyrgyz Republic. The application of the results of scientists\u27, engineers\u27 and specialists\u27 investigations, including inventions in the area of nanotechnology and nanomaterials allow achieving significant efficiency in construction, house and communal service, related sectors of economy. For example, the invention A method to modify concrete with complex additive which includes hydrothermal nanoparticles SiO2 and multi-layer carbon nanotubes refers to methods of modifying concrete by introducing combination of nanoparticles with high specific surface into concrete mixture and can be used in production of precast and monolithic parts and structures of buildings and facilities of different purpose. This method of nanomodifying concrete makes it possible to achieve increased mechanical characteristics of concrete: compressive strength (25-77% at the age of 28 days) and bending strength, resistance to damage, Young\u27s mod of elasticity and shearing modulus, density (up to 10%), accelerated hardening at the early age and rate of strength development, decreased water absorbtion ability and improved indicators of porous structure (pore size and pore differential size uniformity), decreased total capillary porosity, increased frost resistance. The specialists can also be interested in the following nanotechnological inventions: a method to obtain polycrystalline diamond films; phase change materials for building construction: an overview of nano-/microencapsulation, solar collector of transpiration type; a method to obtain composition for antimicrobic coating on the basis of silver sulphide associates with molecules of methylene blue; broadband electromagnetic absorbing coating; a method to produce dry building mixtures; self-organizing nanostructures and separation membrane including aquaporin water channels and the methods to produce and use them; a method to obtain nanocrystalline titanium dioxide with anatase structure, etc. Conclusion. One of the most challenging tasks the economy of every country face is to increase industrial competitiveness through technological upgrade. From the side of the state and companies the principal object to control in this process are the people and enterprises dealing with introduction of inventions and new technologies
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