1,721,002 research outputs found
Misure di precisione della velocità del suono per la determinazione delle proprietà termodinamiche in acqua pura nel campo di temperatura (274 ̧394) K e per pressioni tra 0,1 MPa e 90 MPa
No full textDeterminazione delle proprietà elastiche dei materiali solidi utilizzando un metodo acustico
No full textA new method to calculate the thermodynamical properties of liquids from accurate speed-of-sound measurements
No full textThermodynamic properties of acetone calculated from accurate experimental speed-of-sound measurements at low temperatures and high pressures
No full textA recursive equation method for the determination of density and heat capacity: Comparison between isentropic and isothermal integration paths
No full textCalcolo delle proprietà termodinamiche dei fluidi: il nuovo metodo delle equazioni ricorsive (REM)
No full textA novel application of Recursive Equation Method for determining thermodynamic properties of single phase fluids from density and speed-of-sound measurements
No full textIn this work, the authors suggest a preliminary numerical calculation which allows to determine the constant pressure specific heat capacity, starting from density and speed-of-sound experimental values, as input data.
This method is a variant of the well characterized Recursive Equation Method (REM) [1] and permits to develop empirical equations of state for single phase fluids. In particular, the isobaric specific heat capacity has been obtained, in a wide range of temperatures and pressures, for pure water, n-nonane, n-undecane, and rapeseed oil methyl ester. The results have been compared with those available in the literature, when it was possible. Moreover, the typical uncertainty of heat capacity has been estimated to be in the order of 1.5%; however it has been shown that it can be improved when proper distributions of the experimental points are available
Experimental speed-of-sound measurements of pure fatty acids methyl ester, mineral diesel and blends in a wide range of temperature and for pressures up to 300 MPa
No full textThe variety of biofuels, which was put on the market in recent years, requires a great improvement of existing thermodynamic characterization methods and, eventually, the development of new ones. A deep understanding of the chemico-physical properties of biofuels will help to identify appropriate utilization areas, to improve the efficiency, to reduce the impact on climatic changes through greenhouse gas emission control, and to reduce the dependency on fossil energy.
This work focuses on accurate experimental speed-of-sound measurements of first-generation liquid biofuels, made from renewable sources, which are commonly utilized in existing compression ignition engines, of mineral diesel, and of blends. The fluids under test were rapeseed oil methyl ester (in the following referred as B100-RME), soybean oil methyl ester (B100-SME), blends with 5% of rapeseed oil methyl ester (B5-RME) or 5% of soybean oil methyl ester (B5-SME), blends with 10% of biofuels (B10-RME and B10-SME) in mineral diesel and pure mineral diesel.
Accurate speed-of-sound results were obtained by means of a double reflector pulse-echo technique, in the temperature range from 273.15 K to 353.15 K and over a wide pressure range (from atmospheric pressure up to 300 MPa). The overall uncertainty for speed-of-sound values was estimated to be less than 0.3% over the whole investigated thermodynamical range
Determinazione delle proprietà elastiche di solidi omogenei e non omogenei da misure accurate di velocità del suono
No full textSpeed of Sound Results in 2,3,3,3-Tetrafluoropropene (R-1234yf) and trans-1,3,3,3-Tetrafluoropropene (R-1234ze(E)) in the Temperature Range of (260 to 360) K
No full textSpeed of sound measurements in high purity samples of two novel candidate refrigerants, 2,3,3,3-tetrafluoropropene (R-1234yf) and trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)), are reported along five isotherms in the temperature range of (260 to 360) K and for pressures up to 10 MPa. The experimental technique is based on a double-reflector pulse-echo overlap method. The acoustic path lengths were obtained by a comparison with measurements in pure water carried out at atmospheric conditions. The speed of sound experimental results are characterized by an overall estimated uncertainty of less than of 0.1 %
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