Intrinsic thermal vibrations of suspended doubly clamped single-wall carbon nanotubes

We report the observation of thermally driven mechanical vibrations of suspended doubly clamped carbon nanotubes, grown by chemical vapor deposition (CVD). Several experimental procedures are used to suspend carbon nanotubes. The vibration is observed as a blurring in images taken with a scanning electron microscope. The measured vibration amplitudes are compared with a model based on linear continuum mechanics.Comment: pdf including figures, see: http://www.unibas.ch/phys-meso/Research/Papers/2003/NT-Thermal-Vibrations.pd

SATURN D6.5 - Final Report

The objective of the SATURN (Strategic Allocation of Traffic Using Redistribution in the Network) project is to make novel and credible use of market-based demand-management mechanisms to redistribute air traffic in the European airspace. This reduces congestion and saves the airspace users operational costs. The project is motivated by frequent demand and capacity imbalances in the European airspace network, which are forecast to continue in the near future. The present and foreseen ways of dealing with such imbalances mainly concern strategic and tactical capacity-side interventions, such as resectorisation and opening of more sectors to deal with excess demand. These are followed by tactical demand management measures, if needed. As a result, not only do substantial costs arise, but airspace users are also typically left with no choice but to comply with imposed air traffic flow management measures. The project shows how economic signals could be given to airspace users and air navigation service providers (ANSPs) to improve capacity-demand balancing, airspace design and usage, and what the benefits would be of a centralised planner compared with those of decentralised maximisation of self interests (by the ANSPs and/or airspace users)

Redox Reactions on Anodised or Passivated Metals

The simple redox reactions on anodised or passivated metal (Al, Fe, Zn) were investigated by the current-potential method. The redox systems were chosen so that the electrochemical reaction was practically under the control of the diffusion in the electrolyte in case of unhindered charge transfer in the solid phase and on the contact electrode/electrolyte. Measurements were performed in a wider potential range, but on the previously anodised or passivated metal, in which case the potential range investigated was within the limits corresponding to low equivalent corrosion currents for the pure supporting electrolyte. In all the investigated cases the phenomena were observed, showing that the electron structure of the solid phase and possible potential barriers of the metal/phase layer/solution system had a predominant influence

Bi-Signature optical spectroscopy for online fault detection in electrical machines

A novel bi-signature optical spectroscopy for fault detection in electrical machines is presented. The combined use of long period grating (LPG) and two fibre Bragg gratings (FBG1 and FBG2) is implemented to discriminate between vibration and temperature sensitivity in the detection of machine faults. With LPG having higher sensitivity to temperature compared to both FBGs, machine faults are detected through spectral analysis of both signatures; and the optimal detection signature for each fault is consequently analysed. This novel technique utilises the principle of a shift in the wavelengths of the gratings to determine the kind of fault present in an electrical machine as the signature spectroscopy reveals varying amount of Bragg wavelength shifts for various fault types. The use of FBG sensing for fault detection in electrical machines has the potential of revolutionising non-intrusive real-time condition monitoring of future industrial machines with high reliability due to zero electromagnetic interference (EMI) as well as significant low cost of fibre-optic sensors

Renormalization-group running of the cosmological constant and the fate of the universe

For a generic quantum field theory we study the role played by the renormalization-group (RG) running of the cosmological constant (CC) in determining the ultimate fate of the universe. We consider the running of the CC of generic origin (the vacuum energy of quantum fields and the potential energy of classical fields), with the RG scale proportional to the (total energy density$\rm{)^{1/4}}$ as the most obvious identification. Starting from the present-era values for cosmological parameters we demonstrate how the running can easily provide a negative cosmological constant, thereby changing the fate of the universe, at the same time rendering compatibility with critical string theory. We also briefly discuss the recent past in our scenario.Comment: 9 pages, 7 figures, revtex4; version to appear in PR

Enhanced photocatalytic degradation of RO16 dye using Ag modified ZnO nanopowders prepared by the solvothermal method

In this work, Zn(CH3 COO)(2) 2 H-2 O with AgNO3 content from 0 to 6 mol% was solvothermally treated at 120 C for 18 h in the presence of poly(vinyl pyrrolidone), ethylene glycol and sodium hydroxide. The structural , microstructural and photocatalytic properties of the unmodified and Ag modified ZnO powders have been investigated by the XRPD, FESEM, TEM, UV-vis, Raman and BET techniques. The Ag modified samples consist of ZnO nanocrystals and metallic Ag on the surface. The average crystallite size of all samples was about 20 nm. The FESEM revealed the uniformity in size and approximately spherical shape of ZnO nanopar-ticles. The BET data suggest that all prepared samples are mesoporous. All prepared samples showed higher photocatalytic efficiency in the degradation of the Reactive Orange 16 (RO16) azo dye than the commercial ZnO. In addition, Ag modified ZnO powders, especially those with 1.5 and 0.75 mol% of Ag, were more efficient than the unmodified one

Possible Superconducting State up to 210 K in the new Composition of Y-Ba-Cu-O

We have observed the zero resistance state up to 210 K in the mixed system of nominal composition Yj.2BaOSCu04-prepared under simultaneous action oi pulsed electric field up to 30 kV/cm and uniaxial force of 180 kN. The onset of the decrease of the resistance at 281 K in the repeated cycles and preliminary data diamagnetism are understood by us as a possible superconductivity event related to a particular composition

Environmental Education in Serbian Primary Schools: Challenges and Changes in Curriculum, Pedagogy, and Teacher Training

The protection of human health and the preservation of the environment are topics that form anintegral part of the primary school curriculum in Serbia. However, research studies have shown thatstudents do not have enough knowledge to contribute to the development of a healthy lifestyle andenvironmental awareness. The latest changes in school policy and curricula confirm that the relevanceof environmental education has been recognized, but changes in school practice are yet to come. Thisarticle discusses the challenges encountered in the implementation of the intended curriculum andoffers suggestions for changes to the curriculum, pedagogy, and teacher training in order to enhanceenvironmental educationThis is the peer-reviewd version of the artivle: Stanišić, Jelena, и Slavica Maksić. 2014. „Environmental Education in Serbian Primary Schools: Challenges and Changes in Curriculum, Pedagogy, and Teacher Training“. Journal of Environmental Education 45(2):118–31. doi: 10.1080/00958964.2013.829019.Related to published version: [ http://ipir.ipisr.org.rs/handle/123456789/240