Système d'aide à la décision pour le choix des investissements et la hiérarchisation du renouvellement des installations de gaz à usage collectif

National audienc

Measurement of tree volume by means of non-metric 35mm photography and photogrammetric approach

Forest Mensuration employs certain measurement principles to obtain quantifiable information about the forest for sustainable decision making.  In this paper, a photogrammetric alternative employing 35mm non-metric photography has been suggested and used in the preparation of a Standard Volume Table (SVT) for Forest Mensuration. The forester is afforded volume information about trees in less time and at lower cost, without sacrificing accuracy. Comparisons are made between the photogrammetric and traditional methods used by foresters in measuring tree-volume.  From the three methods – use of the Spiegel Relaskop, measuring tape on felled tree, and the photogrammetric technique developed in this work, volumes were determined using the Huber formula and a regression equation. The use of measuring tape on felled tree to determine tree volume has been known to provide the most reliable volumetric determinations and commonly serves as a standard for such measurements. Results from the photogrammetric technique compared very well with those obtained using measuring tape on felled tree indicating that , photogrammetric technique herein devised proves a more effective means for deriving Tree Volume Tables, if factors like speed, cost, and convenience are considered. &nbsp

[Effects of acoustic treatment of a dialysis room on the quality of life of patients]

International audienceThe impairment of quality of life experienced by patients treated with chronic hemodialysis results from many factors, including the care environment. Current regulations have significantly improved reception and treatment conditions for patients, but perhaps insufficient attention has been paid to the noise nuisance associated with dialysis equipment. We therefore found it useful to conduct a study on acoustic parameters in the dialysis room, and to evaluate the effects on perceived quality of life of an acoustic treatment intended to reduce the level of ambient noise. After measurements carried out under standard conditions, adapted noise absorption (devices panels and trellis) were installed in a treatment room of 8 posts hosting 32 volunteer patients, and their effects evaluated by a quality of life questionnaire administered 3 times (before, at the end of one week, and after the removal of the devices), each patient being his own witness. Measurements of ambient noise during dialysis periods and numerical modeling of the room were performed in parallel in order to search for correlations between the subjective changes expressed by the patients and the quantitative noise criteria. The results show that such devices can significantly reduce the perceived acoustic discomfort and their consequences (headaches), and suggest that these improvements are due to the frequential homogenization of the reverberation time in the room and the reduction of the low frequency components induced by the different sources of noise identified

IEA SHC Task 42 / ECES Annex 29 - A Simple Tool for the Economic Evaluation of Thermal Energy Storages

ACTInternational audienceWithin the framework of IEA SHC Task 42 / ECES Annex 29, a simple tool for the economic evaluation of thermal energy storages has been developed and tested on various existing storages. On that account, the storage capacity costs (costs per installed storage capacity) of thermal energy storages have been evaluated via a Top-down and a Bottom-up approach. The Top-down approach follows the assumption that the costs of energy supplied by the storage should not exceed the costs of energy from the market. The maximum acceptable storage capacity costs depend on the interest rate assigned to the capital costs, the intended payback period of the user class (e.g. industry or building), the reference energy costs, and the annual number of storage cycles. The Bottom-up approach focuses on the realised storage capacity costs of existing storages. The economic evaluation via Top-down and Bottom-up approach is a valuable tool to make a rough estimate of the economic viability of an energy storage for a specific application. An important finding is that the annual number of storage cycles has the largest influence on the cost effectiveness. At present and with respect to the investigated storages, seasonal heat storage is only economical via large sensible hot water storages. Contrary, if the annual number of storage cycles is sufficiently high, all thermal energy storage technologies can become competitive. \textcopyright 2016 The Authors