1,721,084 research outputs found
Influenza degli strati riflettenti superficiali sui carichi termici delle pareti vetrate
No full text
La nuova stazione di misura di proprietà termofisiche dell'Istituto di Energetica dell'Università di Perugia (Rapp. 1, C.N.R., P.F.Edilizia)
No full text
Abstract. The Shrine of the Alamo and its Roof: History and Past Strategies of Recovering
No full textExperimental Determination of the Thermophysical Properties of Water-Xylitol Mixtures
No full textIn the last few years many new refrigerant-absorbent pairs have been proposed for used in heat transformers. Water-Xylitol mixtures are examined in the present paper. The experimental work on water-xylitol mixtures consists of measuring pressure-temperature-concentration data at saturation conditions to trace the whole P-T-X chart. In addition, the specific heat and kinematic viscosity are measured at various concentrations and temperatures. Measurements of specific heat are effected by means of a heat flux calorimeter in the range of temperatures between 313 and 373 K and in the range of concentrations between pure water and saturated solutions. Measurements of viscosity are obtained by means of an Ubbelohde viscosimeter, in the range of temperatures between 273 and 353 K and in the range of concentrations between pure water and saturation. The results from the P-T-X chart verify that the maximum attainable temperature difference between external fluids connected with the engine would be within the range of 5-10 K. Thus, it is concluded that water-xylitol solutions are not suitable for applications in the field of heat transformers and absorption machines
Emissioni da impianti di cogenerazione di differenti tipologie: trattamenti per il disinquinamento, riferimenti legislativi
No full text
Una semplice e affidabile tecnica di misura della portata d'aria ricircolata nei mobiletti locali
No full textAn Active Control Device for Electric Power Plant
No full textThe large electric power generators are powered by diesel engines which produce very high noise levels, usually attenuated by passive mufflers systems, installed along the engines exhaust channels. In this paper, a new active noise control device is proposed, designed to be used in addition to the common passive mufflers ssystems, in order to achive a more elevated attenuation of noise. The device is made up by a box, which contains two power loudspeakers fed by a control circuit, that generates an electrical signal, teh spectral features of which are derived by picking up the electricity produced by the power generator. The acoustic signal emitted by the loudspeakers has the same shape but opposite phase of the signal produced by the engine. The two signals interfere across the final section of the engine exhaust pipe. The device has been installed on a power generator of a telephone exchange station: a noise reduction of about 20 dB was obtained. Furthermore, the mostly attenuated frequency range is 40-200 Hz, where the common passive mufflers systems show a very low efficiency
- …
