Search results for "Heat capacity"
showing 10 items of 90 documents
Specific Heat and Transport Functions of Water
2020
Numerous water characteristics are essentially ascribed to its peculiarity to form stronghydrogen bonds that become progressively more stable on decreasing the temperature. However, thestructural and dynamical implications of the molecular rearrangement are still subject of debate andintense studies. In this work, we observe that the thermodynamic characteristics of liquid water arestrictly connected to its dynamic characteristics. In particular, we compare the thermal behaviourof the isobaric specific heat of water, measured in different confinement conditions at atmosphericpressure (and evaluated by means of theoretical studies) with its configurational contribution obtainedfrom the value…
PCM thermal storage design in buildings: Experimental studies and applications to solaria in cold climates
2017
Abstract As energy availability and demand often do not match, thermal energy storage plays a crucial role to take advantage of solar radiation in buildings: in particular, latent heat storage via phase-change material is particularly attractive due to its ability to provide high energy storage density. This paper analyzes the performance of a building-integrated thermal storage system to increase the energy performances of solaria in a cold climate. A wall opposing a highly glazed facade (south oriented) is used as thermal storage with phase change materials embedded in the wall. The study is based on both experimental and simulation studies. The concept considered is particularly suited t…
Thermal characterization of insulating materials
2018
Abstract The strict energy saving standards are based on the declared values of the materials, i.e. U-value, thermal conductivity or thermal capacity. To this end, proper knowledge of the thermophysical properties of the wall components is needed, especially with regard to new lightweight technologies that are being used in building construction/refurbishment, under the dynamic conditions of the Mediterranean climate, where one of most important parameters of building materials is their heat capacity because of the influence of solar radiation energy. With this regard, the actual heat capacity value, obtained in laboratory tests, is typically quite different from the nominal one. So, this p…
Determination of the Soret coefficient of magnetic particles in a ferrofluid from the steady and unsteady part of the separation curve
2004
Experiments on the particle separation in a vertical thermodiffusion column are used to investigate the separation (Soret effect) in ferrofluids. The use of a two-sectional column with internal walls of low thermal capacity allows analyzing the initial part of the unsteady separation curves as well as the steady state regime. The Soret coefficient calculated from the measurements of the separation dynamics agrees well with the one found from the steady separation limit reached in long-time experiments especially if the solutal buoyancy is low.
Heat Capacity and entanglement
2012
Starting from a recent result on thermodynamic equilibrium of quantum systems, a connection between thermal properties, originating from Gibbs state probabilistic structure, and quantum correlations is discussed as a consequence of entanglement monogamy. As an example, a simple two-qubit system is analyzed, allowing for an expression of such a connection as an explicit function linking heat capacity to a measure of bipartite entanglement.
Density, Speed of Sound, and Refractive Index of 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate with Acetone, Methyl Acetate, and Ethyl Acetat…
2009
Densities, speeds of sound, and refractive indices of the binary mixtures of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][triflate]) with acetone, methyl acetate, and ethyl acetate were experimentally measured over the whole range of compositions at T = (278.15 to 328.15) K and a pressure of 0.1 MPa. From these experimental data, excess molar volumes, excess isentropic compressibilities, molar refractions, and deviations in refractive indices have been calculated and fitted to an extended version of the Redlich−Kister equation, which takes into account the dependence on composition and temperature simultaneously. The Prigogine−Flory−Patterson theory has been used to specula…
Lanthanoid single-ion magnets based on polyoxometalates with a 5-fold symmetry: The series [LnP5W30O110]12– (Ln3+ = Tb, Dy, Ho, Er, Tm, and Yb)
2012
A robust, stable and processable family of mononuclear lanthanoid complexes based on polyoxometalates (POMs) that exhibit single-molecule magnetic behavior is described here. Preyssler polyanions of general formula [LnP 5W 30O 110] 12- (Ln 3+ = Tb, Dy, Ho, Er, Tm, and Yb) have been characterized with static and dynamic magnetic measurements and heat capacity experiments. For the Dy and Ho derivatives, slow relaxation of the magnetization has been found. A simple interpretation of these properties is achieved by using crystal field theory. © 2012 American Chemical Society.
LOCAL-MOMENT AND ITINERANT ANTIFERROMAGNETISM IN THE HEAVY-FERMION SYSTEM CE(CU1-XNIX)2GE2
1992
Elastic and inelastic neutron-scattering studies on the system Ce(Cu1−xNix)2Ge2 are reported. These measurements are complemented by measurements of the magnetic susceptibility, high-field magnetization, heat capacity, thermal expansion, electrical resistivity and thermopower. The results reveal an interesting T-x phase diagram consisting of two different antiferromagnetic phases for x 0.5. Further experimental evidence for different types of antiferromagnetic ordering derives from a line-shape analysis of the quasielastic neutron-scattering intensity, from magnetization and thermopower experiments.
Heat-capacity anomaly due to spin reorientation and thermodynamic functions of ErFeO3 and TmFeO3
2001
Abstract Heat capacities of orthoferrites, ErFeO 3 and TmFeO 3 , have been measured below room temperature by adiabatic calorimetry. A broad but definite anomaly due to the spin reorientation phenomenon was successfully detected in the expected temperature range (ca. 90 K). The results are compared with a vast anomaly reported for YbFeO 3 . The temperature dependence of the electric quadrupole splitting of the Fe nuclear levels was determined by Mossbauer spectroscopy through the spin reorientation. A heat capacity anomaly centered at 3.60 K due to the magnetic ordering of Er 3+ ions was clearly detected. Some Schottky anomalies were resolved and energy splittings involved were roughly esti…
First-principles comparative study of perfect and defective CsPbX3 (X = Br, I) crystals
2020
We thank R. Merkle for numerous fruitful discussions and G. Siegle for experimental assistance. This study was partly supported by the M-ERA-NET project SunToChem (EK). Calculations were performed using computational facilities of St. Petersburg State University and Max Planck Institute for Solid State Research. Open Access funding provided by the Max Planck Society.