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[en] This study presents the investigation of the vibration effect on CHF. The experiments condition was under atmospheric pressure at vertical heated annulus channel. The experiments for dynamic response of the heater section without vibration excitation were carried out at mass flux of 50 kg/m2/s and 400 kg/m2/s. Vibration amplitude was increased at the ONB point during boiling process and the reason of the vibration increase is expected as the results of the flow regime change from subcooled region to bubbly region. CHF experiments with and without mechanical vibration were performed at mass flux of 115 kg/m2/s and 215 kg/m2/s. Totally 162 data of CHF with vibration were gained and CHF was increased by mechanical vibration maximum 13.4 % at the mass flux of 115 kg/m2/s and 16.4 % at the mass flux of 215 kg/m2/s. The maximum CHF enhancement condition was at 30 Hz vibration frequency and 0.5 mm vibration amplitude. The dominant parameter of vibration which was effective on CHF enhancement was vibration amplitude and the reason of the CHF increase is expected as the increase of the liquid film thickness by increase of deposition of liquid droplet on to the film. Vibration was effective not only heat transfer enhancement but also CHF enhancement. Therefore, FIV could be important parameter in CHF enhancement and must be investigated further more
[en] After a contribution of the minister of Ecology and Sustainable Development, a first round table discussed the role of renewable energies in heat production. Then, after a contribution of the minister of Industry, a second round table discussed the role of biofuels. A contribution focuses on innovative sectors and on niche sectors. The third round table discussed the roles of wind and hydraulic energies. The first day is completed by contributions of other ministers (Research and new technologies). Three round tables were held on the second day on the question of risk management, on the solutions regarding wastes, and on the role of nuclear energy in the future, each round table being followed by a debate.
[en] This publication first proposes an overview of the situation of heat networks in social housing. It proposes a synthesis of a locally performed survey. It discusses the competitiveness of urban heating in terms of taxing, of comparison between fuel and heat, of calculation of recoverable costs, of lack of commitment of commissioner, and of hot water production. It comments the situation of the heat distribution public service: relationships between actors, service continuity, price fairness, transparency and simplicity, issue of individualisation, and other aspects. The last part addresses the issue of environmental quality in terms of energy management, energy efficiency, and renewable energy sources.
[en] This parliamentary report first proposes an overview of the evolution of hydrocarbon prices with a brief history since 1930, and a focus on the rather strong increase which has been noticed during the last three years. Reasons for the increase of crude oil price and oil by-product prices are notably discussed. The authors then analyse perspectives of price evolution on the medium term and on the long term. They discuss factors which may influence prices from the supply side as well as from the demand side. They propose and comment scenarios of price evolution. Then, they discuss the impact of oil price increase on the world economy: characteristics of this third oil shock, reasons for its limited but not negligible impact, simulation of the impact of oil price increase by using the Nemesis macro-economic model. The next part addresses possible actions by public authorities with a discussion of risks related to a sustained increase of oil price, possible actions on markets, on oil supply, and on oil demand. Some recommendations are finally stated.
[en] While indicating some key figures and proposing data graphs, this publication describes which energy we consume and what we do with it, and outlines that our energy consumption is increasing every day, that this increase is mainly due to transports, and that only industry has made savings. It describes how we can manage our energy-related expenses (at home, by changing transport habits, in the industry). The next part addresses the evolution towards a sustainable development: struggle against greenhouse effect, a difficult world context, French commitment for the Kyoto protocol. The situation of fossil energies (oil, gas, coal) is then addressed (consumptions in different sectors, shares in the energy consumption in the world and in France). The next part addresses renewable energies (hydraulic, biomass, solar and wind energies) by commenting their share in energy production, how they are adapted to different needs, their costs, their development in overseas territories, and their perspective of development. Nuclear energy is the next topic: its stakes, it high share in electric power production in France, the associated risks which must be managed and monitored, the waste issue. Questions addressed by the different events of the debate on energy are finally indicated.
[en] This book should be considered as a pool of information concerning two basic aspects of nuclear physics: the existence of elementary particles and the possibility of releasing huge amounts of energy. The implications of these 2 aspects are reviewed and parted into 12 chapters: 1) basic nuclear physics, 2) nuclear models and stability of nuclei, 3) nuclear matter exploration, 4) electro-weak interactions, quarks and leptons, 5) radioactivity and its applications, 6) fission, 7) nuclear reactors, 8) fusion, 9) elements of nuclear astrophysics, 10) data about energy, 11) low dose irradiations and 12) nuclear proliferation and safeguards.
[en] The first document reports a study which aimed at providing some new elements regarding the sensitivity of future trajectories of greenhouse gas emissions to various mechanisms or hypotheses of prospective modes, by using the Imaclim-R hybrid model developed at the CIRED. This document reports a complete diagnosis of the state-of-the-art of emission scenarios and of models used to produce them, the further development of the Imaclim-R model, and some sensitivity tests performed with this model. A second document proposes a synthetic presentation of the GICC Programme in 2004 which addressed the conciliation between environmental constraints and national development policies in developing countries, and which aimed as assessing the implementation potential of strategies related to climate policies and development. It notably reports some case studies on the use of biomass energy in Brazil, and the use of coal in India.
[en] As a crucial test for ‘how real are composite ferimons (CF's)’ we have examined the spin states for even-fraction Landau level fillings in the exact diagonalization of finite fractional quantum Hall (FQH) system and those in the CF picture. This is an extension of our recent numerical study for spinless fermions, where a remarkable correspondence in the low-lying excitation spectrum has been found between finite FQH systems and the free CF's in zero magnetic field. The question includes whether the even-fraction states are (fully or partially) spin-polarized or unpolarized. We have shown that both of (i) the total spin and the total angular momentum of the finite FQH system and (ii) spin-resolved low-lying excitation spectra are explained surprisingly well by the CF's in zero magnetic field with Hund(exchange)-coupling of spins.
[en] The author studies dynamics of linked moveable nanoparticles coupled to electron transport, using molecular dynamics and Monte Carlo method. The nanoparticles are found to vibrate periodically and/or quasi-periodically, from the power spectra of the nanoparticle vibrations. The simulation indicates possible transitions between the periodic and quasi-periodic vibrations, which owes to frequency locking and electron tunneling uncorrelated to the nanoparticle motion. These transitions are expected to be a new mechanism which causes random telegraph noise in the current in an array of conductive nanoparticles.
SummaryA robust scheme of moiré interferometry for real-time observation of thermal deformations was developed. It was implemented with a convection-type heating/cooling environmental chamber, which produced rapid temperature control. Vibrations caused by the environmental chamber were circumvented by rigid links that connected the specimen to the moiré interferometer rather than supporting the specimen by the chamber. The result was exceptionally stable fringes. The system was utilized to document temperature-dependent behavior of a PBGA package assembly.